LCOV - code coverage report
Current view: top level - src/backend/postmaster - postmaster.c (source / functions) Hit Total Coverage
Test: PostgreSQL 12beta2 Lines: 1042 1428 73.0 %
Date: 2019-06-19 16:07:09 Functions: 48 54 88.9 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * postmaster.c
       4             :  *    This program acts as a clearing house for requests to the
       5             :  *    POSTGRES system.  Frontend programs send a startup message
       6             :  *    to the Postmaster and the postmaster uses the info in the
       7             :  *    message to setup a backend process.
       8             :  *
       9             :  *    The postmaster also manages system-wide operations such as
      10             :  *    startup and shutdown. The postmaster itself doesn't do those
      11             :  *    operations, mind you --- it just forks off a subprocess to do them
      12             :  *    at the right times.  It also takes care of resetting the system
      13             :  *    if a backend crashes.
      14             :  *
      15             :  *    The postmaster process creates the shared memory and semaphore
      16             :  *    pools during startup, but as a rule does not touch them itself.
      17             :  *    In particular, it is not a member of the PGPROC array of backends
      18             :  *    and so it cannot participate in lock-manager operations.  Keeping
      19             :  *    the postmaster away from shared memory operations makes it simpler
      20             :  *    and more reliable.  The postmaster is almost always able to recover
      21             :  *    from crashes of individual backends by resetting shared memory;
      22             :  *    if it did much with shared memory then it would be prone to crashing
      23             :  *    along with the backends.
      24             :  *
      25             :  *    When a request message is received, we now fork() immediately.
      26             :  *    The child process performs authentication of the request, and
      27             :  *    then becomes a backend if successful.  This allows the auth code
      28             :  *    to be written in a simple single-threaded style (as opposed to the
      29             :  *    crufty "poor man's multitasking" code that used to be needed).
      30             :  *    More importantly, it ensures that blockages in non-multithreaded
      31             :  *    libraries like SSL or PAM cannot cause denial of service to other
      32             :  *    clients.
      33             :  *
      34             :  *
      35             :  * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
      36             :  * Portions Copyright (c) 1994, Regents of the University of California
      37             :  *
      38             :  *
      39             :  * IDENTIFICATION
      40             :  *    src/backend/postmaster/postmaster.c
      41             :  *
      42             :  * NOTES
      43             :  *
      44             :  * Initialization:
      45             :  *      The Postmaster sets up shared memory data structures
      46             :  *      for the backends.
      47             :  *
      48             :  * Synchronization:
      49             :  *      The Postmaster shares memory with the backends but should avoid
      50             :  *      touching shared memory, so as not to become stuck if a crashing
      51             :  *      backend screws up locks or shared memory.  Likewise, the Postmaster
      52             :  *      should never block on messages from frontend clients.
      53             :  *
      54             :  * Garbage Collection:
      55             :  *      The Postmaster cleans up after backends if they have an emergency
      56             :  *      exit and/or core dump.
      57             :  *
      58             :  * Error Reporting:
      59             :  *      Use write_stderr() only for reporting "interactive" errors
      60             :  *      (essentially, bogus arguments on the command line).  Once the
      61             :  *      postmaster is launched, use ereport().
      62             :  *
      63             :  *-------------------------------------------------------------------------
      64             :  */
      65             : 
      66             : #include "postgres.h"
      67             : 
      68             : #include <unistd.h>
      69             : #include <signal.h>
      70             : #include <time.h>
      71             : #include <sys/wait.h>
      72             : #include <ctype.h>
      73             : #include <sys/stat.h>
      74             : #include <sys/socket.h>
      75             : #include <fcntl.h>
      76             : #include <sys/param.h>
      77             : #include <netdb.h>
      78             : #include <limits.h>
      79             : 
      80             : #ifdef HAVE_SYS_SELECT_H
      81             : #include <sys/select.h>
      82             : #endif
      83             : 
      84             : #ifdef USE_BONJOUR
      85             : #include <dns_sd.h>
      86             : #endif
      87             : 
      88             : #ifdef USE_SYSTEMD
      89             : #include <systemd/sd-daemon.h>
      90             : #endif
      91             : 
      92             : #ifdef HAVE_PTHREAD_IS_THREADED_NP
      93             : #include <pthread.h>
      94             : #endif
      95             : 
      96             : #include "access/transam.h"
      97             : #include "access/xlog.h"
      98             : #include "bootstrap/bootstrap.h"
      99             : #include "catalog/pg_control.h"
     100             : #include "common/file_perm.h"
     101             : #include "common/ip.h"
     102             : #include "common/string.h"
     103             : #include "lib/ilist.h"
     104             : #include "libpq/auth.h"
     105             : #include "libpq/libpq.h"
     106             : #include "libpq/pqformat.h"
     107             : #include "libpq/pqsignal.h"
     108             : #include "miscadmin.h"
     109             : #include "pg_getopt.h"
     110             : #include "pgstat.h"
     111             : #include "port/pg_bswap.h"
     112             : #include "postmaster/autovacuum.h"
     113             : #include "postmaster/bgworker_internals.h"
     114             : #include "postmaster/fork_process.h"
     115             : #include "postmaster/pgarch.h"
     116             : #include "postmaster/postmaster.h"
     117             : #include "postmaster/syslogger.h"
     118             : #include "replication/logicallauncher.h"
     119             : #include "replication/walsender.h"
     120             : #include "storage/fd.h"
     121             : #include "storage/ipc.h"
     122             : #include "storage/pg_shmem.h"
     123             : #include "storage/pmsignal.h"
     124             : #include "storage/proc.h"
     125             : #include "tcop/tcopprot.h"
     126             : #include "utils/builtins.h"
     127             : #include "utils/datetime.h"
     128             : #include "utils/memutils.h"
     129             : #include "utils/pidfile.h"
     130             : #include "utils/ps_status.h"
     131             : #include "utils/timeout.h"
     132             : #include "utils/timestamp.h"
     133             : #include "utils/varlena.h"
     134             : 
     135             : #ifdef EXEC_BACKEND
     136             : #include "storage/spin.h"
     137             : #endif
     138             : 
     139             : 
     140             : /*
     141             :  * Possible types of a backend. Beyond being the possible bkend_type values in
     142             :  * struct bkend, these are OR-able request flag bits for SignalSomeChildren()
     143             :  * and CountChildren().
     144             :  */
     145             : #define BACKEND_TYPE_NORMAL     0x0001  /* normal backend */
     146             : #define BACKEND_TYPE_AUTOVAC    0x0002  /* autovacuum worker process */
     147             : #define BACKEND_TYPE_WALSND     0x0004  /* walsender process */
     148             : #define BACKEND_TYPE_BGWORKER   0x0008  /* bgworker process */
     149             : #define BACKEND_TYPE_ALL        0x000F  /* OR of all the above */
     150             : 
     151             : #define BACKEND_TYPE_WORKER     (BACKEND_TYPE_AUTOVAC | BACKEND_TYPE_BGWORKER)
     152             : 
     153             : /*
     154             :  * List of active backends (or child processes anyway; we don't actually
     155             :  * know whether a given child has become a backend or is still in the
     156             :  * authorization phase).  This is used mainly to keep track of how many
     157             :  * children we have and send them appropriate signals when necessary.
     158             :  *
     159             :  * "Special" children such as the startup, bgwriter and autovacuum launcher
     160             :  * tasks are not in this list.  Autovacuum worker and walsender are in it.
     161             :  * Also, "dead_end" children are in it: these are children launched just for
     162             :  * the purpose of sending a friendly rejection message to a would-be client.
     163             :  * We must track them because they are attached to shared memory, but we know
     164             :  * they will never become live backends.  dead_end children are not assigned a
     165             :  * PMChildSlot.
     166             :  *
     167             :  * Background workers are in this list, too.
     168             :  */
     169             : typedef struct bkend
     170             : {
     171             :     pid_t       pid;            /* process id of backend */
     172             :     int32       cancel_key;     /* cancel key for cancels for this backend */
     173             :     int         child_slot;     /* PMChildSlot for this backend, if any */
     174             : 
     175             :     /*
     176             :      * Flavor of backend or auxiliary process.  Note that BACKEND_TYPE_WALSND
     177             :      * backends initially announce themselves as BACKEND_TYPE_NORMAL, so if
     178             :      * bkend_type is normal, you should check for a recent transition.
     179             :      */
     180             :     int         bkend_type;
     181             :     bool        dead_end;       /* is it going to send an error and quit? */
     182             :     bool        bgworker_notify;    /* gets bgworker start/stop notifications */
     183             :     dlist_node  elem;           /* list link in BackendList */
     184             : } Backend;
     185             : 
     186             : static dlist_head BackendList = DLIST_STATIC_INIT(BackendList);
     187             : 
     188             : #ifdef EXEC_BACKEND
     189             : static Backend *ShmemBackendArray;
     190             : #endif
     191             : 
     192             : BackgroundWorker *MyBgworkerEntry = NULL;
     193             : 
     194             : 
     195             : 
     196             : /* The socket number we are listening for connections on */
     197             : int         PostPortNumber;
     198             : 
     199             : /* The directory names for Unix socket(s) */
     200             : char       *Unix_socket_directories;
     201             : 
     202             : /* The TCP listen address(es) */
     203             : char       *ListenAddresses;
     204             : 
     205             : /*
     206             :  * ReservedBackends is the number of backends reserved for superuser use.
     207             :  * This number is taken out of the pool size given by MaxConnections so
     208             :  * number of backend slots available to non-superusers is
     209             :  * (MaxConnections - ReservedBackends).  Note what this really means is
     210             :  * "if there are <= ReservedBackends connections available, only superusers
     211             :  * can make new connections" --- pre-existing superuser connections don't
     212             :  * count against the limit.
     213             :  */
     214             : int         ReservedBackends;
     215             : 
     216             : /* The socket(s) we're listening to. */
     217             : #define MAXLISTEN   64
     218             : static pgsocket ListenSocket[MAXLISTEN];
     219             : 
     220             : /*
     221             :  * Set by the -o option
     222             :  */
     223             : static char ExtraOptions[MAXPGPATH];
     224             : 
     225             : /*
     226             :  * These globals control the behavior of the postmaster in case some
     227             :  * backend dumps core.  Normally, it kills all peers of the dead backend
     228             :  * and reinitializes shared memory.  By specifying -s or -n, we can have
     229             :  * the postmaster stop (rather than kill) peers and not reinitialize
     230             :  * shared data structures.  (Reinit is currently dead code, though.)
     231             :  */
     232             : static bool Reinit = true;
     233             : static int  SendStop = false;
     234             : 
     235             : /* still more option variables */
     236             : bool        EnableSSL = false;
     237             : 
     238             : int         PreAuthDelay = 0;
     239             : int         AuthenticationTimeout = 60;
     240             : 
     241             : bool        log_hostname;       /* for ps display and logging */
     242             : bool        Log_connections = false;
     243             : bool        Db_user_namespace = false;
     244             : 
     245             : bool        enable_bonjour = false;
     246             : char       *bonjour_name;
     247             : bool        restart_after_crash = true;
     248             : 
     249             : /* PIDs of special child processes; 0 when not running */
     250             : static pid_t StartupPID = 0,
     251             :             BgWriterPID = 0,
     252             :             CheckpointerPID = 0,
     253             :             WalWriterPID = 0,
     254             :             WalReceiverPID = 0,
     255             :             AutoVacPID = 0,
     256             :             PgArchPID = 0,
     257             :             PgStatPID = 0,
     258             :             SysLoggerPID = 0;
     259             : 
     260             : /* Startup process's status */
     261             : typedef enum
     262             : {
     263             :     STARTUP_NOT_RUNNING,
     264             :     STARTUP_RUNNING,
     265             :     STARTUP_SIGNALED,           /* we sent it a SIGQUIT or SIGKILL */
     266             :     STARTUP_CRASHED
     267             : } StartupStatusEnum;
     268             : 
     269             : static StartupStatusEnum StartupStatus = STARTUP_NOT_RUNNING;
     270             : 
     271             : /* Startup/shutdown state */
     272             : #define         NoShutdown      0
     273             : #define         SmartShutdown   1
     274             : #define         FastShutdown    2
     275             : #define         ImmediateShutdown   3
     276             : 
     277             : static int  Shutdown = NoShutdown;
     278             : 
     279             : static bool FatalError = false; /* T if recovering from backend crash */
     280             : 
     281             : /*
     282             :  * We use a simple state machine to control startup, shutdown, and
     283             :  * crash recovery (which is rather like shutdown followed by startup).
     284             :  *
     285             :  * After doing all the postmaster initialization work, we enter PM_STARTUP
     286             :  * state and the startup process is launched. The startup process begins by
     287             :  * reading the control file and other preliminary initialization steps.
     288             :  * In a normal startup, or after crash recovery, the startup process exits
     289             :  * with exit code 0 and we switch to PM_RUN state.  However, archive recovery
     290             :  * is handled specially since it takes much longer and we would like to support
     291             :  * hot standby during archive recovery.
     292             :  *
     293             :  * When the startup process is ready to start archive recovery, it signals the
     294             :  * postmaster, and we switch to PM_RECOVERY state. The background writer and
     295             :  * checkpointer are launched, while the startup process continues applying WAL.
     296             :  * If Hot Standby is enabled, then, after reaching a consistent point in WAL
     297             :  * redo, startup process signals us again, and we switch to PM_HOT_STANDBY
     298             :  * state and begin accepting connections to perform read-only queries.  When
     299             :  * archive recovery is finished, the startup process exits with exit code 0
     300             :  * and we switch to PM_RUN state.
     301             :  *
     302             :  * Normal child backends can only be launched when we are in PM_RUN or
     303             :  * PM_HOT_STANDBY state.  (We also allow launch of normal
     304             :  * child backends in PM_WAIT_BACKUP state, but only for superusers.)
     305             :  * In other states we handle connection requests by launching "dead_end"
     306             :  * child processes, which will simply send the client an error message and
     307             :  * quit.  (We track these in the BackendList so that we can know when they
     308             :  * are all gone; this is important because they're still connected to shared
     309             :  * memory, and would interfere with an attempt to destroy the shmem segment,
     310             :  * possibly leading to SHMALL failure when we try to make a new one.)
     311             :  * In PM_WAIT_DEAD_END state we are waiting for all the dead_end children
     312             :  * to drain out of the system, and therefore stop accepting connection
     313             :  * requests at all until the last existing child has quit (which hopefully
     314             :  * will not be very long).
     315             :  *
     316             :  * Notice that this state variable does not distinguish *why* we entered
     317             :  * states later than PM_RUN --- Shutdown and FatalError must be consulted
     318             :  * to find that out.  FatalError is never true in PM_RECOVERY_* or PM_RUN
     319             :  * states, nor in PM_SHUTDOWN states (because we don't enter those states
     320             :  * when trying to recover from a crash).  It can be true in PM_STARTUP state,
     321             :  * because we don't clear it until we've successfully started WAL redo.
     322             :  */
     323             : typedef enum
     324             : {
     325             :     PM_INIT,                    /* postmaster starting */
     326             :     PM_STARTUP,                 /* waiting for startup subprocess */
     327             :     PM_RECOVERY,                /* in archive recovery mode */
     328             :     PM_HOT_STANDBY,             /* in hot standby mode */
     329             :     PM_RUN,                     /* normal "database is alive" state */
     330             :     PM_WAIT_BACKUP,             /* waiting for online backup mode to end */
     331             :     PM_WAIT_READONLY,           /* waiting for read only backends to exit */
     332             :     PM_WAIT_BACKENDS,           /* waiting for live backends to exit */
     333             :     PM_SHUTDOWN,                /* waiting for checkpointer to do shutdown
     334             :                                  * ckpt */
     335             :     PM_SHUTDOWN_2,              /* waiting for archiver and walsenders to
     336             :                                  * finish */
     337             :     PM_WAIT_DEAD_END,           /* waiting for dead_end children to exit */
     338             :     PM_NO_CHILDREN              /* all important children have exited */
     339             : } PMState;
     340             : 
     341             : static PMState pmState = PM_INIT;
     342             : 
     343             : /* Start time of SIGKILL timeout during immediate shutdown or child crash */
     344             : /* Zero means timeout is not running */
     345             : static time_t AbortStartTime = 0;
     346             : 
     347             : /* Length of said timeout */
     348             : #define SIGKILL_CHILDREN_AFTER_SECS     5
     349             : 
     350             : static bool ReachedNormalRunning = false;   /* T if we've reached PM_RUN */
     351             : 
     352             : bool        ClientAuthInProgress = false;   /* T during new-client
     353             :                                              * authentication */
     354             : 
     355             : bool        redirection_done = false;   /* stderr redirected for syslogger? */
     356             : 
     357             : /* received START_AUTOVAC_LAUNCHER signal */
     358             : static volatile sig_atomic_t start_autovac_launcher = false;
     359             : 
     360             : /* the launcher needs to be signalled to communicate some condition */
     361             : static volatile bool avlauncher_needs_signal = false;
     362             : 
     363             : /* received START_WALRECEIVER signal */
     364             : static volatile sig_atomic_t WalReceiverRequested = false;
     365             : 
     366             : /* set when there's a worker that needs to be started up */
     367             : static volatile bool StartWorkerNeeded = true;
     368             : static volatile bool HaveCrashedWorker = false;
     369             : 
     370             : #ifdef USE_SSL
     371             : /* Set when and if SSL has been initialized properly */
     372             : static bool LoadedSSL = false;
     373             : #endif
     374             : 
     375             : #ifdef USE_BONJOUR
     376             : static DNSServiceRef bonjour_sdref = NULL;
     377             : #endif
     378             : 
     379             : /*
     380             :  * postmaster.c - function prototypes
     381             :  */
     382             : static void CloseServerPorts(int status, Datum arg);
     383             : static void unlink_external_pid_file(int status, Datum arg);
     384             : static void getInstallationPaths(const char *argv0);
     385             : static void checkControlFile(void);
     386             : static Port *ConnCreate(int serverFd);
     387             : static void ConnFree(Port *port);
     388             : static void reset_shared(int port);
     389             : static void SIGHUP_handler(SIGNAL_ARGS);
     390             : static void pmdie(SIGNAL_ARGS);
     391             : static void reaper(SIGNAL_ARGS);
     392             : static void sigusr1_handler(SIGNAL_ARGS);
     393             : static void startup_die(SIGNAL_ARGS);
     394             : static void dummy_handler(SIGNAL_ARGS);
     395             : static void StartupPacketTimeoutHandler(void);
     396             : static void CleanupBackend(int pid, int exitstatus);
     397             : static bool CleanupBackgroundWorker(int pid, int exitstatus);
     398             : static void HandleChildCrash(int pid, int exitstatus, const char *procname);
     399             : static void LogChildExit(int lev, const char *procname,
     400             :                          int pid, int exitstatus);
     401             : static void PostmasterStateMachine(void);
     402             : static void BackendInitialize(Port *port);
     403             : static void BackendRun(Port *port) pg_attribute_noreturn();
     404             : static void ExitPostmaster(int status) pg_attribute_noreturn();
     405             : static int  ServerLoop(void);
     406             : static int  BackendStartup(Port *port);
     407             : static int  ProcessStartupPacket(Port *port, bool secure_done);
     408             : static void SendNegotiateProtocolVersion(List *unrecognized_protocol_options);
     409             : static void processCancelRequest(Port *port, void *pkt);
     410             : static int  initMasks(fd_set *rmask);
     411             : static void report_fork_failure_to_client(Port *port, int errnum);
     412             : static CAC_state canAcceptConnections(void);
     413             : static bool RandomCancelKey(int32 *cancel_key);
     414             : static void signal_child(pid_t pid, int signal);
     415             : static bool SignalSomeChildren(int signal, int targets);
     416             : static void TerminateChildren(int signal);
     417             : 
     418             : #define SignalChildren(sig)            SignalSomeChildren(sig, BACKEND_TYPE_ALL)
     419             : 
     420             : static int  CountChildren(int target);
     421             : static bool assign_backendlist_entry(RegisteredBgWorker *rw);
     422             : static void maybe_start_bgworkers(void);
     423             : static bool CreateOptsFile(int argc, char *argv[], char *fullprogname);
     424             : static pid_t StartChildProcess(AuxProcType type);
     425             : static void StartAutovacuumWorker(void);
     426             : static void MaybeStartWalReceiver(void);
     427             : static void InitPostmasterDeathWatchHandle(void);
     428             : 
     429             : /*
     430             :  * Archiver is allowed to start up at the current postmaster state?
     431             :  *
     432             :  * If WAL archiving is enabled always, we are allowed to start archiver
     433             :  * even during recovery.
     434             :  */
     435             : #define PgArchStartupAllowed()  \
     436             :     ((XLogArchivingActive() && pmState == PM_RUN) ||    \
     437             :      (XLogArchivingAlways() &&  \
     438             :       (pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY)))
     439             : 
     440             : #ifdef EXEC_BACKEND
     441             : 
     442             : #ifdef WIN32
     443             : #define WNOHANG 0               /* ignored, so any integer value will do */
     444             : 
     445             : static pid_t waitpid(pid_t pid, int *exitstatus, int options);
     446             : static void WINAPI pgwin32_deadchild_callback(PVOID lpParameter, BOOLEAN TimerOrWaitFired);
     447             : 
     448             : static HANDLE win32ChildQueue;
     449             : 
     450             : typedef struct
     451             : {
     452             :     HANDLE      waitHandle;
     453             :     HANDLE      procHandle;
     454             :     DWORD       procId;
     455             : } win32_deadchild_waitinfo;
     456             : #endif                          /* WIN32 */
     457             : 
     458             : static pid_t backend_forkexec(Port *port);
     459             : static pid_t internal_forkexec(int argc, char *argv[], Port *port);
     460             : 
     461             : /* Type for a socket that can be inherited to a client process */
     462             : #ifdef WIN32
     463             : typedef struct
     464             : {
     465             :     SOCKET      origsocket;     /* Original socket value, or PGINVALID_SOCKET
     466             :                                  * if not a socket */
     467             :     WSAPROTOCOL_INFO wsainfo;
     468             : } InheritableSocket;
     469             : #else
     470             : typedef int InheritableSocket;
     471             : #endif
     472             : 
     473             : /*
     474             :  * Structure contains all variables passed to exec:ed backends
     475             :  */
     476             : typedef struct
     477             : {
     478             :     Port        port;
     479             :     InheritableSocket portsocket;
     480             :     char        DataDir[MAXPGPATH];
     481             :     pgsocket    ListenSocket[MAXLISTEN];
     482             :     int32       MyCancelKey;
     483             :     int         MyPMChildSlot;
     484             : #ifndef WIN32
     485             :     unsigned long UsedShmemSegID;
     486             : #else
     487             :     void       *ShmemProtectiveRegion;
     488             :     HANDLE      UsedShmemSegID;
     489             : #endif
     490             :     void       *UsedShmemSegAddr;
     491             :     slock_t    *ShmemLock;
     492             :     VariableCache ShmemVariableCache;
     493             :     Backend    *ShmemBackendArray;
     494             : #ifndef HAVE_SPINLOCKS
     495             :     PGSemaphore *SpinlockSemaArray;
     496             : #endif
     497             :     int         NamedLWLockTrancheRequests;
     498             :     NamedLWLockTranche *NamedLWLockTrancheArray;
     499             :     LWLockPadded *MainLWLockArray;
     500             :     slock_t    *ProcStructLock;
     501             :     PROC_HDR   *ProcGlobal;
     502             :     PGPROC     *AuxiliaryProcs;
     503             :     PGPROC     *PreparedXactProcs;
     504             :     PMSignalData *PMSignalState;
     505             :     InheritableSocket pgStatSock;
     506             :     pid_t       PostmasterPid;
     507             :     TimestampTz PgStartTime;
     508             :     TimestampTz PgReloadTime;
     509             :     pg_time_t   first_syslogger_file_time;
     510             :     bool        redirection_done;
     511             :     bool        IsBinaryUpgrade;
     512             :     int         max_safe_fds;
     513             :     int         MaxBackends;
     514             : #ifdef WIN32
     515             :     HANDLE      PostmasterHandle;
     516             :     HANDLE      initial_signal_pipe;
     517             :     HANDLE      syslogPipe[2];
     518             : #else
     519             :     int         postmaster_alive_fds[2];
     520             :     int         syslogPipe[2];
     521             : #endif
     522             :     char        my_exec_path[MAXPGPATH];
     523             :     char        pkglib_path[MAXPGPATH];
     524             :     char        ExtraOptions[MAXPGPATH];
     525             : } BackendParameters;
     526             : 
     527             : static void read_backend_variables(char *id, Port *port);
     528             : static void restore_backend_variables(BackendParameters *param, Port *port);
     529             : 
     530             : #ifndef WIN32
     531             : static bool save_backend_variables(BackendParameters *param, Port *port);
     532             : #else
     533             : static bool save_backend_variables(BackendParameters *param, Port *port,
     534             :                                    HANDLE childProcess, pid_t childPid);
     535             : #endif
     536             : 
     537             : static void ShmemBackendArrayAdd(Backend *bn);
     538             : static void ShmemBackendArrayRemove(Backend *bn);
     539             : #endif                          /* EXEC_BACKEND */
     540             : 
     541             : #define StartupDataBase()       StartChildProcess(StartupProcess)
     542             : #define StartBackgroundWriter() StartChildProcess(BgWriterProcess)
     543             : #define StartCheckpointer()     StartChildProcess(CheckpointerProcess)
     544             : #define StartWalWriter()        StartChildProcess(WalWriterProcess)
     545             : #define StartWalReceiver()      StartChildProcess(WalReceiverProcess)
     546             : 
     547             : /* Macros to check exit status of a child process */
     548             : #define EXIT_STATUS_0(st)  ((st) == 0)
     549             : #define EXIT_STATUS_1(st)  (WIFEXITED(st) && WEXITSTATUS(st) == 1)
     550             : #define EXIT_STATUS_3(st)  (WIFEXITED(st) && WEXITSTATUS(st) == 3)
     551             : 
     552             : #ifndef WIN32
     553             : /*
     554             :  * File descriptors for pipe used to monitor if postmaster is alive.
     555             :  * First is POSTMASTER_FD_WATCH, second is POSTMASTER_FD_OWN.
     556             :  */
     557             : int         postmaster_alive_fds[2] = {-1, -1};
     558             : #else
     559             : /* Process handle of postmaster used for the same purpose on Windows */
     560             : HANDLE      PostmasterHandle;
     561             : #endif
     562             : 
     563             : /*
     564             :  * Postmaster main entry point
     565             :  */
     566             : void
     567         580 : PostmasterMain(int argc, char *argv[])
     568             : {
     569             :     int         opt;
     570             :     int         status;
     571         580 :     char       *userDoption = NULL;
     572         580 :     bool        listen_addr_saved = false;
     573             :     int         i;
     574         580 :     char       *output_config_variable = NULL;
     575             : 
     576         580 :     InitProcessGlobals();
     577             : 
     578         580 :     PostmasterPid = MyProcPid;
     579             : 
     580         580 :     IsPostmasterEnvironment = true;
     581             : 
     582             :     /*
     583             :      * We should not be creating any files or directories before we check the
     584             :      * data directory (see checkDataDir()), but just in case set the umask to
     585             :      * the most restrictive (owner-only) permissions.
     586             :      *
     587             :      * checkDataDir() will reset the umask based on the data directory
     588             :      * permissions.
     589             :      */
     590         580 :     umask(PG_MODE_MASK_OWNER);
     591             : 
     592             :     /*
     593             :      * By default, palloc() requests in the postmaster will be allocated in
     594             :      * the PostmasterContext, which is space that can be recycled by backends.
     595             :      * Allocated data that needs to be available to backends should be
     596             :      * allocated in TopMemoryContext.
     597             :      */
     598         580 :     PostmasterContext = AllocSetContextCreate(TopMemoryContext,
     599             :                                               "Postmaster",
     600             :                                               ALLOCSET_DEFAULT_SIZES);
     601         580 :     MemoryContextSwitchTo(PostmasterContext);
     602             : 
     603             :     /* Initialize paths to installation files */
     604         580 :     getInstallationPaths(argv[0]);
     605             : 
     606             :     /*
     607             :      * Set up signal handlers for the postmaster process.
     608             :      *
     609             :      * In the postmaster, we want to install non-ignored handlers *without*
     610             :      * SA_RESTART.  This is because they'll be blocked at all times except
     611             :      * when ServerLoop is waiting for something to happen, and during that
     612             :      * window, we want signals to exit the select(2) wait so that ServerLoop
     613             :      * can respond if anything interesting happened.  On some platforms,
     614             :      * signals marked SA_RESTART would not cause the select() wait to end.
     615             :      * Child processes will generally want SA_RESTART, but we expect them to
     616             :      * set up their own handlers before unblocking signals.
     617             :      *
     618             :      * CAUTION: when changing this list, check for side-effects on the signal
     619             :      * handling setup of child processes.  See tcop/postgres.c,
     620             :      * bootstrap/bootstrap.c, postmaster/bgwriter.c, postmaster/walwriter.c,
     621             :      * postmaster/autovacuum.c, postmaster/pgarch.c, postmaster/pgstat.c,
     622             :      * postmaster/syslogger.c, postmaster/bgworker.c and
     623             :      * postmaster/checkpointer.c.
     624             :      */
     625         580 :     pqinitmask();
     626         580 :     PG_SETMASK(&BlockSig);
     627             : 
     628         580 :     pqsignal_no_restart(SIGHUP, SIGHUP_handler);    /* reread config file and
     629             :                                                      * have children do same */
     630         580 :     pqsignal_no_restart(SIGINT, pmdie); /* send SIGTERM and shut down */
     631         580 :     pqsignal_no_restart(SIGQUIT, pmdie);    /* send SIGQUIT and die */
     632         580 :     pqsignal_no_restart(SIGTERM, pmdie);    /* wait for children and shut down */
     633         580 :     pqsignal(SIGALRM, SIG_IGN); /* ignored */
     634         580 :     pqsignal(SIGPIPE, SIG_IGN); /* ignored */
     635         580 :     pqsignal_no_restart(SIGUSR1, sigusr1_handler);  /* message from child
     636             :                                                      * process */
     637         580 :     pqsignal_no_restart(SIGUSR2, dummy_handler);    /* unused, reserve for
     638             :                                                      * children */
     639         580 :     pqsignal_no_restart(SIGCHLD, reaper);   /* handle child termination */
     640             : 
     641             :     /*
     642             :      * No other place in Postgres should touch SIGTTIN/SIGTTOU handling.  We
     643             :      * ignore those signals in a postmaster environment, so that there is no
     644             :      * risk of a child process freezing up due to writing to stderr.  But for
     645             :      * a standalone backend, their default handling is reasonable.  Hence, all
     646             :      * child processes should just allow the inherited settings to stand.
     647             :      */
     648             : #ifdef SIGTTIN
     649         580 :     pqsignal(SIGTTIN, SIG_IGN); /* ignored */
     650             : #endif
     651             : #ifdef SIGTTOU
     652         580 :     pqsignal(SIGTTOU, SIG_IGN); /* ignored */
     653             : #endif
     654             : 
     655             :     /* ignore SIGXFSZ, so that ulimit violations work like disk full */
     656             : #ifdef SIGXFSZ
     657         580 :     pqsignal(SIGXFSZ, SIG_IGN); /* ignored */
     658             : #endif
     659             : 
     660             :     /*
     661             :      * Options setup
     662             :      */
     663         580 :     InitializeGUCOptions();
     664             : 
     665         580 :     opterr = 1;
     666             : 
     667             :     /*
     668             :      * Parse command-line options.  CAUTION: keep this in sync with
     669             :      * tcop/postgres.c (the option sets should not conflict) and with the
     670             :      * common help() function in main/main.c.
     671             :      */
     672        2602 :     while ((opt = getopt(argc, argv, "B:bc:C:D:d:EeFf:h:ijk:lN:nOo:Pp:r:S:sTt:W:-:")) != -1)
     673             :     {
     674        1442 :         switch (opt)
     675             :         {
     676             :             case 'B':
     677           0 :                 SetConfigOption("shared_buffers", optarg, PGC_POSTMASTER, PGC_S_ARGV);
     678           0 :                 break;
     679             : 
     680             :             case 'b':
     681             :                 /* Undocumented flag used for binary upgrades */
     682           8 :                 IsBinaryUpgrade = true;
     683           8 :                 break;
     684             : 
     685             :             case 'C':
     686           0 :                 output_config_variable = strdup(optarg);
     687           0 :                 break;
     688             : 
     689             :             case 'D':
     690         576 :                 userDoption = strdup(optarg);
     691         576 :                 break;
     692             : 
     693             :             case 'd':
     694           0 :                 set_debug_options(atoi(optarg), PGC_POSTMASTER, PGC_S_ARGV);
     695           0 :                 break;
     696             : 
     697             :             case 'E':
     698           0 :                 SetConfigOption("log_statement", "all", PGC_POSTMASTER, PGC_S_ARGV);
     699           0 :                 break;
     700             : 
     701             :             case 'e':
     702           0 :                 SetConfigOption("datestyle", "euro", PGC_POSTMASTER, PGC_S_ARGV);
     703           0 :                 break;
     704             : 
     705             :             case 'F':
     706         128 :                 SetConfigOption("fsync", "false", PGC_POSTMASTER, PGC_S_ARGV);
     707         128 :                 break;
     708             : 
     709             :             case 'f':
     710           0 :                 if (!set_plan_disabling_options(optarg, PGC_POSTMASTER, PGC_S_ARGV))
     711             :                 {
     712           0 :                     write_stderr("%s: invalid argument for option -f: \"%s\"\n",
     713             :                                  progname, optarg);
     714           0 :                     ExitPostmaster(1);
     715             :                 }
     716           0 :                 break;
     717             : 
     718             :             case 'h':
     719           0 :                 SetConfigOption("listen_addresses", optarg, PGC_POSTMASTER, PGC_S_ARGV);
     720           0 :                 break;
     721             : 
     722             :             case 'i':
     723           0 :                 SetConfigOption("listen_addresses", "*", PGC_POSTMASTER, PGC_S_ARGV);
     724           0 :                 break;
     725             : 
     726             :             case 'j':
     727             :                 /* only used by interactive backend */
     728           0 :                 break;
     729             : 
     730             :             case 'k':
     731         128 :                 SetConfigOption("unix_socket_directories", optarg, PGC_POSTMASTER, PGC_S_ARGV);
     732         128 :                 break;
     733             : 
     734             :             case 'l':
     735           0 :                 SetConfigOption("ssl", "true", PGC_POSTMASTER, PGC_S_ARGV);
     736           0 :                 break;
     737             : 
     738             :             case 'N':
     739           0 :                 SetConfigOption("max_connections", optarg, PGC_POSTMASTER, PGC_S_ARGV);
     740           0 :                 break;
     741             : 
     742             :             case 'n':
     743             :                 /* Don't reinit shared mem after abnormal exit */
     744           0 :                 Reinit = false;
     745           0 :                 break;
     746             : 
     747             :             case 'O':
     748           0 :                 SetConfigOption("allow_system_table_mods", "true", PGC_POSTMASTER, PGC_S_ARGV);
     749           0 :                 break;
     750             : 
     751             :             case 'o':
     752             :                 /* Other options to pass to the backend on the command line */
     753           0 :                 snprintf(ExtraOptions + strlen(ExtraOptions),
     754           0 :                          sizeof(ExtraOptions) - strlen(ExtraOptions),
     755             :                          " %s", optarg);
     756           0 :                 break;
     757             : 
     758             :             case 'P':
     759           0 :                 SetConfigOption("ignore_system_indexes", "true", PGC_POSTMASTER, PGC_S_ARGV);
     760           0 :                 break;
     761             : 
     762             :             case 'p':
     763           8 :                 SetConfigOption("port", optarg, PGC_POSTMASTER, PGC_S_ARGV);
     764           8 :                 break;
     765             : 
     766             :             case 'r':
     767             :                 /* only used by single-user backend */
     768           0 :                 break;
     769             : 
     770             :             case 'S':
     771           0 :                 SetConfigOption("work_mem", optarg, PGC_POSTMASTER, PGC_S_ARGV);
     772           0 :                 break;
     773             : 
     774             :             case 's':
     775           0 :                 SetConfigOption("log_statement_stats", "true", PGC_POSTMASTER, PGC_S_ARGV);
     776           0 :                 break;
     777             : 
     778             :             case 'T':
     779             : 
     780             :                 /*
     781             :                  * In the event that some backend dumps core, send SIGSTOP,
     782             :                  * rather than SIGQUIT, to all its peers.  This lets the wily
     783             :                  * post_hacker collect core dumps from everyone.
     784             :                  */
     785           0 :                 SendStop = true;
     786           0 :                 break;
     787             : 
     788             :             case 't':
     789             :                 {
     790           0 :                     const char *tmp = get_stats_option_name(optarg);
     791             : 
     792           0 :                     if (tmp)
     793             :                     {
     794           0 :                         SetConfigOption(tmp, "true", PGC_POSTMASTER, PGC_S_ARGV);
     795             :                     }
     796             :                     else
     797             :                     {
     798           0 :                         write_stderr("%s: invalid argument for option -t: \"%s\"\n",
     799             :                                      progname, optarg);
     800           0 :                         ExitPostmaster(1);
     801             :                     }
     802           0 :                     break;
     803             :                 }
     804             : 
     805             :             case 'W':
     806           0 :                 SetConfigOption("post_auth_delay", optarg, PGC_POSTMASTER, PGC_S_ARGV);
     807           0 :                 break;
     808             : 
     809             :             case 'c':
     810             :             case '-':
     811             :                 {
     812             :                     char       *name,
     813             :                                *value;
     814             : 
     815         594 :                     ParseLongOption(optarg, &name, &value);
     816         594 :                     if (!value)
     817             :                     {
     818           0 :                         if (opt == '-')
     819           0 :                             ereport(ERROR,
     820             :                                     (errcode(ERRCODE_SYNTAX_ERROR),
     821             :                                      errmsg("--%s requires a value",
     822             :                                             optarg)));
     823             :                         else
     824           0 :                             ereport(ERROR,
     825             :                                     (errcode(ERRCODE_SYNTAX_ERROR),
     826             :                                      errmsg("-c %s requires a value",
     827             :                                             optarg)));
     828             :                     }
     829             : 
     830         594 :                     SetConfigOption(name, value, PGC_POSTMASTER, PGC_S_ARGV);
     831         594 :                     free(name);
     832         594 :                     if (value)
     833         594 :                         free(value);
     834         594 :                     break;
     835             :                 }
     836             : 
     837             :             default:
     838           0 :                 write_stderr("Try \"%s --help\" for more information.\n",
     839             :                              progname);
     840           0 :                 ExitPostmaster(1);
     841             :         }
     842             :     }
     843             : 
     844             :     /*
     845             :      * Postmaster accepts no non-option switch arguments.
     846             :      */
     847         580 :     if (optind < argc)
     848             :     {
     849           0 :         write_stderr("%s: invalid argument: \"%s\"\n",
     850           0 :                      progname, argv[optind]);
     851           0 :         write_stderr("Try \"%s --help\" for more information.\n",
     852             :                      progname);
     853           0 :         ExitPostmaster(1);
     854             :     }
     855             : 
     856             :     /*
     857             :      * Locate the proper configuration files and data directory, and read
     858             :      * postgresql.conf for the first time.
     859             :      */
     860         580 :     if (!SelectConfigFiles(userDoption, progname))
     861           0 :         ExitPostmaster(2);
     862             : 
     863         578 :     if (output_config_variable != NULL)
     864             :     {
     865             :         /*
     866             :          * "-C guc" was specified, so print GUC's value and exit.  No extra
     867             :          * permission check is needed because the user is reading inside the
     868             :          * data dir.
     869             :          */
     870           0 :         const char *config_val = GetConfigOption(output_config_variable,
     871             :                                                  false, false);
     872             : 
     873           0 :         puts(config_val ? config_val : "");
     874           0 :         ExitPostmaster(0);
     875             :     }
     876             : 
     877             :     /* Verify that DataDir looks reasonable */
     878         578 :     checkDataDir();
     879             : 
     880             :     /* Check that pg_control exists */
     881         578 :     checkControlFile();
     882             : 
     883             :     /* And switch working directory into it */
     884         578 :     ChangeToDataDir();
     885             : 
     886             :     /*
     887             :      * Check for invalid combinations of GUC settings.
     888             :      */
     889         578 :     if (ReservedBackends >= MaxConnections)
     890             :     {
     891           0 :         write_stderr("%s: superuser_reserved_connections (%d) must be less than max_connections (%d)\n",
     892             :                      progname,
     893             :                      ReservedBackends, MaxConnections);
     894           0 :         ExitPostmaster(1);
     895             :     }
     896         578 :     if (XLogArchiveMode > ARCHIVE_MODE_OFF && wal_level == WAL_LEVEL_MINIMAL)
     897           0 :         ereport(ERROR,
     898             :                 (errmsg("WAL archival cannot be enabled when wal_level is \"minimal\"")));
     899         578 :     if (max_wal_senders > 0 && wal_level == WAL_LEVEL_MINIMAL)
     900           0 :         ereport(ERROR,
     901             :                 (errmsg("WAL streaming (max_wal_senders > 0) requires wal_level \"replica\" or \"logical\"")));
     902             : 
     903             :     /*
     904             :      * Other one-time internal sanity checks can go here, if they are fast.
     905             :      * (Put any slow processing further down, after postmaster.pid creation.)
     906             :      */
     907         578 :     if (!CheckDateTokenTables())
     908             :     {
     909           0 :         write_stderr("%s: invalid datetoken tables, please fix\n", progname);
     910           0 :         ExitPostmaster(1);
     911             :     }
     912             : 
     913             :     /*
     914             :      * Now that we are done processing the postmaster arguments, reset
     915             :      * getopt(3) library so that it will work correctly in subprocesses.
     916             :      */
     917         578 :     optind = 1;
     918             : #ifdef HAVE_INT_OPTRESET
     919             :     optreset = 1;               /* some systems need this too */
     920             : #endif
     921             : 
     922             :     /* For debugging: display postmaster environment */
     923             :     {
     924             :         extern char **environ;
     925             :         char      **p;
     926             : 
     927         578 :         ereport(DEBUG3,
     928             :                 (errmsg_internal("%s: PostmasterMain: initial environment dump:",
     929             :                                  progname)));
     930         578 :         ereport(DEBUG3,
     931             :                 (errmsg_internal("-----------------------------------------")));
     932       20388 :         for (p = environ; *p; ++p)
     933       19810 :             ereport(DEBUG3,
     934             :                     (errmsg_internal("\t%s", *p)));
     935         578 :         ereport(DEBUG3,
     936             :                 (errmsg_internal("-----------------------------------------")));
     937             :     }
     938             : 
     939             :     /*
     940             :      * Create lockfile for data directory.
     941             :      *
     942             :      * We want to do this before we try to grab the input sockets, because the
     943             :      * data directory interlock is more reliable than the socket-file
     944             :      * interlock (thanks to whoever decided to put socket files in /tmp :-().
     945             :      * For the same reason, it's best to grab the TCP socket(s) before the
     946             :      * Unix socket(s).
     947             :      *
     948             :      * Also note that this internally sets up the on_proc_exit function that
     949             :      * is responsible for removing both data directory and socket lockfiles;
     950             :      * so it must happen before opening sockets so that at exit, the socket
     951             :      * lockfiles go away after CloseServerPorts runs.
     952             :      */
     953         578 :     CreateDataDirLockFile(true);
     954             : 
     955             :     /*
     956             :      * Read the control file (for error checking and config info).
     957             :      *
     958             :      * Since we verify the control file's CRC, this has a useful side effect
     959             :      * on machines where we need a run-time test for CRC support instructions.
     960             :      * The postmaster will do the test once at startup, and then its child
     961             :      * processes will inherit the correct function pointer and not need to
     962             :      * repeat the test.
     963             :      */
     964         576 :     LocalProcessControlFile(false);
     965             : 
     966             :     /*
     967             :      * Initialize SSL library, if specified.
     968             :      */
     969             : #ifdef USE_SSL
     970         576 :     if (EnableSSL)
     971             :     {
     972          20 :         (void) secure_initialize(true);
     973          18 :         LoadedSSL = true;
     974             :     }
     975             : #endif
     976             : 
     977             :     /*
     978             :      * Register the apply launcher.  Since it registers a background worker,
     979             :      * it needs to be called before InitializeMaxBackends(), and it's probably
     980             :      * a good idea to call it before any modules had chance to take the
     981             :      * background worker slots.
     982             :      */
     983         574 :     ApplyLauncherRegister();
     984             : 
     985             :     /*
     986             :      * process any libraries that should be preloaded at postmaster start
     987             :      */
     988         574 :     process_shared_preload_libraries();
     989             : 
     990             :     /*
     991             :      * Now that loadable modules have had their chance to register background
     992             :      * workers, calculate MaxBackends.
     993             :      */
     994         574 :     InitializeMaxBackends();
     995             : 
     996             :     /* Report server startup in log */
     997         574 :     ereport(LOG,
     998             :             (errmsg("starting %s", PG_VERSION_STR)));
     999             : 
    1000             :     /*
    1001             :      * Establish input sockets.
    1002             :      *
    1003             :      * First, mark them all closed, and set up an on_proc_exit function that's
    1004             :      * charged with closing the sockets again at postmaster shutdown.
    1005             :      */
    1006       37310 :     for (i = 0; i < MAXLISTEN; i++)
    1007       36736 :         ListenSocket[i] = PGINVALID_SOCKET;
    1008             : 
    1009         574 :     on_proc_exit(CloseServerPorts, 0);
    1010             : 
    1011         574 :     if (ListenAddresses)
    1012             :     {
    1013             :         char       *rawstring;
    1014             :         List       *elemlist;
    1015             :         ListCell   *l;
    1016         574 :         int         success = 0;
    1017             : 
    1018             :         /* Need a modifiable copy of ListenAddresses */
    1019         574 :         rawstring = pstrdup(ListenAddresses);
    1020             : 
    1021             :         /* Parse string into list of hostnames */
    1022         574 :         if (!SplitIdentifierString(rawstring, ',', &elemlist))
    1023             :         {
    1024             :             /* syntax error in list */
    1025           0 :             ereport(FATAL,
    1026             :                     (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    1027             :                      errmsg("invalid list syntax in parameter \"%s\"",
    1028             :                             "listen_addresses")));
    1029             :         }
    1030             : 
    1031         598 :         foreach(l, elemlist)
    1032             :         {
    1033          24 :             char       *curhost = (char *) lfirst(l);
    1034             : 
    1035          24 :             if (strcmp(curhost, "*") == 0)
    1036           0 :                 status = StreamServerPort(AF_UNSPEC, NULL,
    1037           0 :                                           (unsigned short) PostPortNumber,
    1038             :                                           NULL,
    1039             :                                           ListenSocket, MAXLISTEN);
    1040             :             else
    1041          24 :                 status = StreamServerPort(AF_UNSPEC, curhost,
    1042          24 :                                           (unsigned short) PostPortNumber,
    1043             :                                           NULL,
    1044             :                                           ListenSocket, MAXLISTEN);
    1045             : 
    1046          24 :             if (status == STATUS_OK)
    1047             :             {
    1048          24 :                 success++;
    1049             :                 /* record the first successful host addr in lockfile */
    1050          24 :                 if (!listen_addr_saved)
    1051             :                 {
    1052          24 :                     AddToDataDirLockFile(LOCK_FILE_LINE_LISTEN_ADDR, curhost);
    1053          24 :                     listen_addr_saved = true;
    1054             :                 }
    1055             :             }
    1056             :             else
    1057           0 :                 ereport(WARNING,
    1058             :                         (errmsg("could not create listen socket for \"%s\"",
    1059             :                                 curhost)));
    1060             :         }
    1061             : 
    1062         574 :         if (!success && elemlist != NIL)
    1063           0 :             ereport(FATAL,
    1064             :                     (errmsg("could not create any TCP/IP sockets")));
    1065             : 
    1066         574 :         list_free(elemlist);
    1067         574 :         pfree(rawstring);
    1068             :     }
    1069             : 
    1070             : #ifdef USE_BONJOUR
    1071             :     /* Register for Bonjour only if we opened TCP socket(s) */
    1072             :     if (enable_bonjour && ListenSocket[0] != PGINVALID_SOCKET)
    1073             :     {
    1074             :         DNSServiceErrorType err;
    1075             : 
    1076             :         /*
    1077             :          * We pass 0 for interface_index, which will result in registering on
    1078             :          * all "applicable" interfaces.  It's not entirely clear from the
    1079             :          * DNS-SD docs whether this would be appropriate if we have bound to
    1080             :          * just a subset of the available network interfaces.
    1081             :          */
    1082             :         err = DNSServiceRegister(&bonjour_sdref,
    1083             :                                  0,
    1084             :                                  0,
    1085             :                                  bonjour_name,
    1086             :                                  "_postgresql._tcp.",
    1087             :                                  NULL,
    1088             :                                  NULL,
    1089             :                                  pg_hton16(PostPortNumber),
    1090             :                                  0,
    1091             :                                  NULL,
    1092             :                                  NULL,
    1093             :                                  NULL);
    1094             :         if (err != kDNSServiceErr_NoError)
    1095             :             elog(LOG, "DNSServiceRegister() failed: error code %ld",
    1096             :                  (long) err);
    1097             : 
    1098             :         /*
    1099             :          * We don't bother to read the mDNS daemon's reply, and we expect that
    1100             :          * it will automatically terminate our registration when the socket is
    1101             :          * closed at postmaster termination.  So there's nothing more to be
    1102             :          * done here.  However, the bonjour_sdref is kept around so that
    1103             :          * forked children can close their copies of the socket.
    1104             :          */
    1105             :     }
    1106             : #endif
    1107             : 
    1108             : #ifdef HAVE_UNIX_SOCKETS
    1109         574 :     if (Unix_socket_directories)
    1110             :     {
    1111             :         char       *rawstring;
    1112             :         List       *elemlist;
    1113             :         ListCell   *l;
    1114         574 :         int         success = 0;
    1115             : 
    1116             :         /* Need a modifiable copy of Unix_socket_directories */
    1117         574 :         rawstring = pstrdup(Unix_socket_directories);
    1118             : 
    1119             :         /* Parse string into list of directories */
    1120         574 :         if (!SplitDirectoriesString(rawstring, ',', &elemlist))
    1121             :         {
    1122             :             /* syntax error in list */
    1123           0 :             ereport(FATAL,
    1124             :                     (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    1125             :                      errmsg("invalid list syntax in parameter \"%s\"",
    1126             :                             "unix_socket_directories")));
    1127             :         }
    1128             : 
    1129        1146 :         foreach(l, elemlist)
    1130             :         {
    1131         572 :             char       *socketdir = (char *) lfirst(l);
    1132             : 
    1133         572 :             status = StreamServerPort(AF_UNIX, NULL,
    1134         572 :                                       (unsigned short) PostPortNumber,
    1135             :                                       socketdir,
    1136             :                                       ListenSocket, MAXLISTEN);
    1137             : 
    1138         572 :             if (status == STATUS_OK)
    1139             :             {
    1140         572 :                 success++;
    1141             :                 /* record the first successful Unix socket in lockfile */
    1142         572 :                 if (success == 1)
    1143         572 :                     AddToDataDirLockFile(LOCK_FILE_LINE_SOCKET_DIR, socketdir);
    1144             :             }
    1145             :             else
    1146           0 :                 ereport(WARNING,
    1147             :                         (errmsg("could not create Unix-domain socket in directory \"%s\"",
    1148             :                                 socketdir)));
    1149             :         }
    1150             : 
    1151         574 :         if (!success && elemlist != NIL)
    1152           0 :             ereport(FATAL,
    1153             :                     (errmsg("could not create any Unix-domain sockets")));
    1154             : 
    1155         574 :         list_free_deep(elemlist);
    1156         574 :         pfree(rawstring);
    1157             :     }
    1158             : #endif
    1159             : 
    1160             :     /*
    1161             :      * check that we have some socket to listen on
    1162             :      */
    1163         574 :     if (ListenSocket[0] == PGINVALID_SOCKET)
    1164           0 :         ereport(FATAL,
    1165             :                 (errmsg("no socket created for listening")));
    1166             : 
    1167             :     /*
    1168             :      * If no valid TCP ports, write an empty line for listen address,
    1169             :      * indicating the Unix socket must be used.  Note that this line is not
    1170             :      * added to the lock file until there is a socket backing it.
    1171             :      */
    1172         574 :     if (!listen_addr_saved)
    1173         550 :         AddToDataDirLockFile(LOCK_FILE_LINE_LISTEN_ADDR, "");
    1174             : 
    1175             :     /*
    1176             :      * Set up shared memory and semaphores.
    1177             :      */
    1178         574 :     reset_shared(PostPortNumber);
    1179             : 
    1180             :     /*
    1181             :      * Estimate number of openable files.  This must happen after setting up
    1182             :      * semaphores, because on some platforms semaphores count as open files.
    1183             :      */
    1184         572 :     set_max_safe_fds();
    1185             : 
    1186             :     /*
    1187             :      * Set reference point for stack-depth checking.
    1188             :      */
    1189         572 :     set_stack_base();
    1190             : 
    1191             :     /*
    1192             :      * Initialize pipe (or process handle on Windows) that allows children to
    1193             :      * wake up from sleep on postmaster death.
    1194             :      */
    1195         572 :     InitPostmasterDeathWatchHandle();
    1196             : 
    1197             : #ifdef WIN32
    1198             : 
    1199             :     /*
    1200             :      * Initialize I/O completion port used to deliver list of dead children.
    1201             :      */
    1202             :     win32ChildQueue = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 1);
    1203             :     if (win32ChildQueue == NULL)
    1204             :         ereport(FATAL,
    1205             :                 (errmsg("could not create I/O completion port for child queue")));
    1206             : #endif
    1207             : 
    1208             :     /*
    1209             :      * Record postmaster options.  We delay this till now to avoid recording
    1210             :      * bogus options (eg, NBuffers too high for available memory).
    1211             :      */
    1212         572 :     if (!CreateOptsFile(argc, argv, my_exec_path))
    1213           0 :         ExitPostmaster(1);
    1214             : 
    1215             : #ifdef EXEC_BACKEND
    1216             :     /* Write out nondefault GUC settings for child processes to use */
    1217             :     write_nondefault_variables(PGC_POSTMASTER);
    1218             : #endif
    1219             : 
    1220             :     /*
    1221             :      * Write the external PID file if requested
    1222             :      */
    1223         572 :     if (external_pid_file)
    1224             :     {
    1225           0 :         FILE       *fpidfile = fopen(external_pid_file, "w");
    1226             : 
    1227           0 :         if (fpidfile)
    1228             :         {
    1229           0 :             fprintf(fpidfile, "%d\n", MyProcPid);
    1230           0 :             fclose(fpidfile);
    1231             : 
    1232             :             /* Make PID file world readable */
    1233           0 :             if (chmod(external_pid_file, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH) != 0)
    1234           0 :                 write_stderr("%s: could not change permissions of external PID file \"%s\": %s\n",
    1235           0 :                              progname, external_pid_file, strerror(errno));
    1236             :         }
    1237             :         else
    1238           0 :             write_stderr("%s: could not write external PID file \"%s\": %s\n",
    1239           0 :                          progname, external_pid_file, strerror(errno));
    1240             : 
    1241           0 :         on_proc_exit(unlink_external_pid_file, 0);
    1242             :     }
    1243             : 
    1244             :     /*
    1245             :      * Remove old temporary files.  At this point there can be no other
    1246             :      * Postgres processes running in this directory, so this should be safe.
    1247             :      */
    1248         572 :     RemovePgTempFiles();
    1249             : 
    1250             :     /*
    1251             :      * Forcibly remove the files signaling a standby promotion request.
    1252             :      * Otherwise, the existence of those files triggers a promotion too early,
    1253             :      * whether a user wants that or not.
    1254             :      *
    1255             :      * This removal of files is usually unnecessary because they can exist
    1256             :      * only during a few moments during a standby promotion. However there is
    1257             :      * a race condition: if pg_ctl promote is executed and creates the files
    1258             :      * during a promotion, the files can stay around even after the server is
    1259             :      * brought up to new master. Then, if new standby starts by using the
    1260             :      * backup taken from that master, the files can exist at the server
    1261             :      * startup and should be removed in order to avoid an unexpected
    1262             :      * promotion.
    1263             :      *
    1264             :      * Note that promotion signal files need to be removed before the startup
    1265             :      * process is invoked. Because, after that, they can be used by
    1266             :      * postmaster's SIGUSR1 signal handler.
    1267             :      */
    1268         572 :     RemovePromoteSignalFiles();
    1269             : 
    1270             :     /* Do the same for logrotate signal file */
    1271         572 :     RemoveLogrotateSignalFiles();
    1272             : 
    1273             :     /* Remove any outdated file holding the current log filenames. */
    1274         572 :     if (unlink(LOG_METAINFO_DATAFILE) < 0 && errno != ENOENT)
    1275           0 :         ereport(LOG,
    1276             :                 (errcode_for_file_access(),
    1277             :                  errmsg("could not remove file \"%s\": %m",
    1278             :                         LOG_METAINFO_DATAFILE)));
    1279             : 
    1280             :     /*
    1281             :      * If enabled, start up syslogger collection subprocess
    1282             :      */
    1283         572 :     SysLoggerPID = SysLogger_Start();
    1284             : 
    1285             :     /*
    1286             :      * Reset whereToSendOutput from DestDebug (its starting state) to
    1287             :      * DestNone. This stops ereport from sending log messages to stderr unless
    1288             :      * Log_destination permits.  We don't do this until the postmaster is
    1289             :      * fully launched, since startup failures may as well be reported to
    1290             :      * stderr.
    1291             :      *
    1292             :      * If we are in fact disabling logging to stderr, first emit a log message
    1293             :      * saying so, to provide a breadcrumb trail for users who may not remember
    1294             :      * that their logging is configured to go somewhere else.
    1295             :      */
    1296         572 :     if (!(Log_destination & LOG_DESTINATION_STDERR))
    1297           0 :         ereport(LOG,
    1298             :                 (errmsg("ending log output to stderr"),
    1299             :                  errhint("Future log output will go to log destination \"%s\".",
    1300             :                          Log_destination_string)));
    1301             : 
    1302         572 :     whereToSendOutput = DestNone;
    1303             : 
    1304             :     /*
    1305             :      * Initialize stats collection subsystem (this does NOT start the
    1306             :      * collector process!)
    1307             :      */
    1308         572 :     pgstat_init();
    1309             : 
    1310             :     /*
    1311             :      * Initialize the autovacuum subsystem (again, no process start yet)
    1312             :      */
    1313         572 :     autovac_init();
    1314             : 
    1315             :     /*
    1316             :      * Load configuration files for client authentication.
    1317             :      */
    1318         572 :     if (!load_hba())
    1319             :     {
    1320             :         /*
    1321             :          * It makes no sense to continue if we fail to load the HBA file,
    1322             :          * since there is no way to connect to the database in this case.
    1323             :          */
    1324           0 :         ereport(FATAL,
    1325             :                 (errmsg("could not load pg_hba.conf")));
    1326             :     }
    1327         572 :     if (!load_ident())
    1328             :     {
    1329             :         /*
    1330             :          * We can start up without the IDENT file, although it means that you
    1331             :          * cannot log in using any of the authentication methods that need a
    1332             :          * user name mapping. load_ident() already logged the details of error
    1333             :          * to the log.
    1334             :          */
    1335             :     }
    1336             : 
    1337             : #ifdef HAVE_PTHREAD_IS_THREADED_NP
    1338             : 
    1339             :     /*
    1340             :      * On macOS, libintl replaces setlocale() with a version that calls
    1341             :      * CFLocaleCopyCurrent() when its second argument is "" and every relevant
    1342             :      * environment variable is unset or empty.  CFLocaleCopyCurrent() makes
    1343             :      * the process multithreaded.  The postmaster calls sigprocmask() and
    1344             :      * calls fork() without an immediate exec(), both of which have undefined
    1345             :      * behavior in a multithreaded program.  A multithreaded postmaster is the
    1346             :      * normal case on Windows, which offers neither fork() nor sigprocmask().
    1347             :      */
    1348             :     if (pthread_is_threaded_np() != 0)
    1349             :         ereport(FATAL,
    1350             :                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
    1351             :                  errmsg("postmaster became multithreaded during startup"),
    1352             :                  errhint("Set the LC_ALL environment variable to a valid locale.")));
    1353             : #endif
    1354             : 
    1355             :     /*
    1356             :      * Remember postmaster startup time
    1357             :      */
    1358         572 :     PgStartTime = GetCurrentTimestamp();
    1359             : 
    1360             :     /*
    1361             :      * Report postmaster status in the postmaster.pid file, to allow pg_ctl to
    1362             :      * see what's happening.
    1363             :      */
    1364         572 :     AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STARTING);
    1365             : 
    1366             :     /*
    1367             :      * We're ready to rock and roll...
    1368             :      */
    1369         572 :     StartupPID = StartupDataBase();
    1370             :     Assert(StartupPID != 0);
    1371         572 :     StartupStatus = STARTUP_RUNNING;
    1372         572 :     pmState = PM_STARTUP;
    1373             : 
    1374             :     /* Some workers may be scheduled to start now */
    1375         572 :     maybe_start_bgworkers();
    1376             : 
    1377         572 :     status = ServerLoop();
    1378             : 
    1379             :     /*
    1380             :      * ServerLoop probably shouldn't ever return, but if it does, close down.
    1381             :      */
    1382           0 :     ExitPostmaster(status != STATUS_OK);
    1383             : 
    1384             :     abort();                    /* not reached */
    1385             : }
    1386             : 
    1387             : 
    1388             : /*
    1389             :  * on_proc_exit callback to close server's listen sockets
    1390             :  */
    1391             : static void
    1392         570 : CloseServerPorts(int status, Datum arg)
    1393             : {
    1394             :     int         i;
    1395             : 
    1396             :     /*
    1397             :      * First, explicitly close all the socket FDs.  We used to just let this
    1398             :      * happen implicitly at postmaster exit, but it's better to close them
    1399             :      * before we remove the postmaster.pid lockfile; otherwise there's a race
    1400             :      * condition if a new postmaster wants to re-use the TCP port number.
    1401             :      */
    1402       37050 :     for (i = 0; i < MAXLISTEN; i++)
    1403             :     {
    1404       36480 :         if (ListenSocket[i] != PGINVALID_SOCKET)
    1405             :         {
    1406         594 :             StreamClose(ListenSocket[i]);
    1407         594 :             ListenSocket[i] = PGINVALID_SOCKET;
    1408             :         }
    1409             :     }
    1410             : 
    1411             :     /*
    1412             :      * Next, remove any filesystem entries for Unix sockets.  To avoid race
    1413             :      * conditions against incoming postmasters, this must happen after closing
    1414             :      * the sockets and before removing lock files.
    1415             :      */
    1416         570 :     RemoveSocketFiles();
    1417             : 
    1418             :     /*
    1419             :      * We don't do anything about socket lock files here; those will be
    1420             :      * removed in a later on_proc_exit callback.
    1421             :      */
    1422         570 : }
    1423             : 
    1424             : /*
    1425             :  * on_proc_exit callback to delete external_pid_file
    1426             :  */
    1427             : static void
    1428           0 : unlink_external_pid_file(int status, Datum arg)
    1429             : {
    1430           0 :     if (external_pid_file)
    1431           0 :         unlink(external_pid_file);
    1432           0 : }
    1433             : 
    1434             : 
    1435             : /*
    1436             :  * Compute and check the directory paths to files that are part of the
    1437             :  * installation (as deduced from the postgres executable's own location)
    1438             :  */
    1439             : static void
    1440         580 : getInstallationPaths(const char *argv0)
    1441             : {
    1442             :     DIR        *pdir;
    1443             : 
    1444             :     /* Locate the postgres executable itself */
    1445         580 :     if (find_my_exec(argv0, my_exec_path) < 0)
    1446           0 :         elog(FATAL, "%s: could not locate my own executable path", argv0);
    1447             : 
    1448             : #ifdef EXEC_BACKEND
    1449             :     /* Locate executable backend before we change working directory */
    1450             :     if (find_other_exec(argv0, "postgres", PG_BACKEND_VERSIONSTR,
    1451             :                         postgres_exec_path) < 0)
    1452             :         ereport(FATAL,
    1453             :                 (errmsg("%s: could not locate matching postgres executable",
    1454             :                         argv0)));
    1455             : #endif
    1456             : 
    1457             :     /*
    1458             :      * Locate the pkglib directory --- this has to be set early in case we try
    1459             :      * to load any modules from it in response to postgresql.conf entries.
    1460             :      */
    1461         580 :     get_pkglib_path(my_exec_path, pkglib_path);
    1462             : 
    1463             :     /*
    1464             :      * Verify that there's a readable directory there; otherwise the Postgres
    1465             :      * installation is incomplete or corrupt.  (A typical cause of this
    1466             :      * failure is that the postgres executable has been moved or hardlinked to
    1467             :      * some directory that's not a sibling of the installation lib/
    1468             :      * directory.)
    1469             :      */
    1470         580 :     pdir = AllocateDir(pkglib_path);
    1471         580 :     if (pdir == NULL)
    1472           0 :         ereport(ERROR,
    1473             :                 (errcode_for_file_access(),
    1474             :                  errmsg("could not open directory \"%s\": %m",
    1475             :                         pkglib_path),
    1476             :                  errhint("This may indicate an incomplete PostgreSQL installation, or that the file \"%s\" has been moved away from its proper location.",
    1477             :                          my_exec_path)));
    1478         580 :     FreeDir(pdir);
    1479             : 
    1480             :     /*
    1481             :      * XXX is it worth similarly checking the share/ directory?  If the lib/
    1482             :      * directory is there, then share/ probably is too.
    1483             :      */
    1484         580 : }
    1485             : 
    1486             : /*
    1487             :  * Check that pg_control exists in the correct location in the data directory.
    1488             :  *
    1489             :  * No attempt is made to validate the contents of pg_control here.  This is
    1490             :  * just a sanity check to see if we are looking at a real data directory.
    1491             :  */
    1492             : static void
    1493         578 : checkControlFile(void)
    1494             : {
    1495             :     char        path[MAXPGPATH];
    1496             :     FILE       *fp;
    1497             : 
    1498         578 :     snprintf(path, sizeof(path), "%s/global/pg_control", DataDir);
    1499             : 
    1500         578 :     fp = AllocateFile(path, PG_BINARY_R);
    1501         578 :     if (fp == NULL)
    1502             :     {
    1503           0 :         write_stderr("%s: could not find the database system\n"
    1504             :                      "Expected to find it in the directory \"%s\",\n"
    1505             :                      "but could not open file \"%s\": %s\n",
    1506           0 :                      progname, DataDir, path, strerror(errno));
    1507           0 :         ExitPostmaster(2);
    1508             :     }
    1509         578 :     FreeFile(fp);
    1510         578 : }
    1511             : 
    1512             : /*
    1513             :  * Determine how long should we let ServerLoop sleep.
    1514             :  *
    1515             :  * In normal conditions we wait at most one minute, to ensure that the other
    1516             :  * background tasks handled by ServerLoop get done even when no requests are
    1517             :  * arriving.  However, if there are background workers waiting to be started,
    1518             :  * we don't actually sleep so that they are quickly serviced.  Other exception
    1519             :  * cases are as shown in the code.
    1520             :  */
    1521             : static void
    1522       16628 : DetermineSleepTime(struct timeval *timeout)
    1523             : {
    1524       16628 :     TimestampTz next_wakeup = 0;
    1525             : 
    1526             :     /*
    1527             :      * Normal case: either there are no background workers at all, or we're in
    1528             :      * a shutdown sequence (during which we ignore bgworkers altogether).
    1529             :      */
    1530       30732 :     if (Shutdown > NoShutdown ||
    1531       28208 :         (!StartWorkerNeeded && !HaveCrashedWorker))
    1532             :     {
    1533       16628 :         if (AbortStartTime != 0)
    1534             :         {
    1535             :             /* time left to abort; clamp to 0 in case it already expired */
    1536         496 :             timeout->tv_sec = SIGKILL_CHILDREN_AFTER_SECS -
    1537         496 :                 (time(NULL) - AbortStartTime);
    1538         496 :             timeout->tv_sec = Max(timeout->tv_sec, 0);
    1539         496 :             timeout->tv_usec = 0;
    1540             :         }
    1541             :         else
    1542             :         {
    1543       16132 :             timeout->tv_sec = 60;
    1544       16132 :             timeout->tv_usec = 0;
    1545             :         }
    1546       16628 :         return;
    1547             :     }
    1548             : 
    1549           0 :     if (StartWorkerNeeded)
    1550             :     {
    1551           0 :         timeout->tv_sec = 0;
    1552           0 :         timeout->tv_usec = 0;
    1553           0 :         return;
    1554             :     }
    1555             : 
    1556           0 :     if (HaveCrashedWorker)
    1557             :     {
    1558             :         slist_mutable_iter siter;
    1559             : 
    1560             :         /*
    1561             :          * When there are crashed bgworkers, we sleep just long enough that
    1562             :          * they are restarted when they request to be.  Scan the list to
    1563             :          * determine the minimum of all wakeup times according to most recent
    1564             :          * crash time and requested restart interval.
    1565             :          */
    1566           0 :         slist_foreach_modify(siter, &BackgroundWorkerList)
    1567             :         {
    1568             :             RegisteredBgWorker *rw;
    1569             :             TimestampTz this_wakeup;
    1570             : 
    1571           0 :             rw = slist_container(RegisteredBgWorker, rw_lnode, siter.cur);
    1572             : 
    1573           0 :             if (rw->rw_crashed_at == 0)
    1574           0 :                 continue;
    1575             : 
    1576           0 :             if (rw->rw_worker.bgw_restart_time == BGW_NEVER_RESTART
    1577           0 :                 || rw->rw_terminate)
    1578             :             {
    1579           0 :                 ForgetBackgroundWorker(&siter);
    1580           0 :                 continue;
    1581             :             }
    1582             : 
    1583           0 :             this_wakeup = TimestampTzPlusMilliseconds(rw->rw_crashed_at,
    1584             :                                                       1000L * rw->rw_worker.bgw_restart_time);
    1585           0 :             if (next_wakeup == 0 || this_wakeup < next_wakeup)
    1586           0 :                 next_wakeup = this_wakeup;
    1587             :         }
    1588             :     }
    1589             : 
    1590           0 :     if (next_wakeup != 0)
    1591             :     {
    1592             :         long        secs;
    1593             :         int         microsecs;
    1594             : 
    1595           0 :         TimestampDifference(GetCurrentTimestamp(), next_wakeup,
    1596             :                             &secs, &microsecs);
    1597           0 :         timeout->tv_sec = secs;
    1598           0 :         timeout->tv_usec = microsecs;
    1599             : 
    1600             :         /* Ensure we don't exceed one minute */
    1601           0 :         if (timeout->tv_sec > 60)
    1602             :         {
    1603           0 :             timeout->tv_sec = 60;
    1604           0 :             timeout->tv_usec = 0;
    1605             :         }
    1606             :     }
    1607             :     else
    1608             :     {
    1609           0 :         timeout->tv_sec = 60;
    1610           0 :         timeout->tv_usec = 0;
    1611             :     }
    1612             : }
    1613             : 
    1614             : /*
    1615             :  * Main idle loop of postmaster
    1616             :  *
    1617             :  * NB: Needs to be called with signals blocked
    1618             :  */
    1619             : static int
    1620         572 : ServerLoop(void)
    1621             : {
    1622             :     fd_set      readmask;
    1623             :     int         nSockets;
    1624             :     time_t      last_lockfile_recheck_time,
    1625             :                 last_touch_time;
    1626             : 
    1627         572 :     last_lockfile_recheck_time = last_touch_time = time(NULL);
    1628             : 
    1629         572 :     nSockets = initMasks(&readmask);
    1630             : 
    1631             :     for (;;)
    1632       16616 :     {
    1633             :         fd_set      rmask;
    1634             :         int         selres;
    1635             :         time_t      now;
    1636             : 
    1637             :         /*
    1638             :          * Wait for a connection request to arrive.
    1639             :          *
    1640             :          * We block all signals except while sleeping. That makes it safe for
    1641             :          * signal handlers, which again block all signals while executing, to
    1642             :          * do nontrivial work.
    1643             :          *
    1644             :          * If we are in PM_WAIT_DEAD_END state, then we don't want to accept
    1645             :          * any new connections, so we don't call select(), and just sleep.
    1646             :          */
    1647       17188 :         memcpy((char *) &rmask, (char *) &readmask, sizeof(fd_set));
    1648             : 
    1649       17188 :         if (pmState == PM_WAIT_DEAD_END)
    1650             :         {
    1651         560 :             PG_SETMASK(&UnBlockSig);
    1652             : 
    1653         560 :             pg_usleep(100000L); /* 100 msec seems reasonable */
    1654          18 :             selres = 0;
    1655             : 
    1656          18 :             PG_SETMASK(&BlockSig);
    1657             :         }
    1658             :         else
    1659             :         {
    1660             :             /* must set timeout each time; some OSes change it! */
    1661             :             struct timeval timeout;
    1662             : 
    1663             :             /* Needs to run with blocked signals! */
    1664       16628 :             DetermineSleepTime(&timeout);
    1665             : 
    1666       16628 :             PG_SETMASK(&UnBlockSig);
    1667             : 
    1668       16628 :             selres = select(nSockets, &rmask, NULL, NULL, &timeout);
    1669             : 
    1670       16600 :             PG_SETMASK(&BlockSig);
    1671             :         }
    1672             : 
    1673             :         /* Now check the select() result */
    1674       16618 :         if (selres < 0)
    1675             :         {
    1676        9730 :             if (errno != EINTR && errno != EWOULDBLOCK)
    1677             :             {
    1678           0 :                 ereport(LOG,
    1679             :                         (errcode_for_socket_access(),
    1680             :                          errmsg("select() failed in postmaster: %m")));
    1681           0 :                 return STATUS_ERROR;
    1682             :             }
    1683             :         }
    1684             : 
    1685             :         /*
    1686             :          * New connection pending on any of our sockets? If so, fork a child
    1687             :          * process to deal with it.
    1688             :          */
    1689       16618 :         if (selres > 0)
    1690             :         {
    1691             :             int         i;
    1692             : 
    1693       14128 :             for (i = 0; i < MAXLISTEN; i++)
    1694             :             {
    1695       14128 :                 if (ListenSocket[i] == PGINVALID_SOCKET)
    1696        6868 :                     break;
    1697        7260 :                 if (FD_ISSET(ListenSocket[i], &rmask))
    1698             :                 {
    1699             :                     Port       *port;
    1700             : 
    1701        6870 :                     port = ConnCreate(ListenSocket[i]);
    1702        6870 :                     if (port)
    1703             :                     {
    1704        6870 :                         BackendStartup(port);
    1705             : 
    1706             :                         /*
    1707             :                          * We no longer need the open socket or port structure
    1708             :                          * in this process
    1709             :                          */
    1710        6868 :                         StreamClose(port->sock);
    1711        6868 :                         ConnFree(port);
    1712             :                     }
    1713             :                 }
    1714             :             }
    1715             :         }
    1716             : 
    1717             :         /* If we have lost the log collector, try to start a new one */
    1718       16616 :         if (SysLoggerPID == 0 && Logging_collector)
    1719           0 :             SysLoggerPID = SysLogger_Start();
    1720             : 
    1721             :         /*
    1722             :          * If no background writer process is running, and we are not in a
    1723             :          * state that prevents it, start one.  It doesn't matter if this
    1724             :          * fails, we'll just try again later.  Likewise for the checkpointer.
    1725             :          */
    1726       20634 :         if (pmState == PM_RUN || pmState == PM_RECOVERY ||
    1727        4018 :             pmState == PM_HOT_STANDBY)
    1728             :         {
    1729       13416 :             if (CheckpointerPID == 0)
    1730           0 :                 CheckpointerPID = StartCheckpointer();
    1731       13416 :             if (BgWriterPID == 0)
    1732           0 :                 BgWriterPID = StartBackgroundWriter();
    1733             :         }
    1734             : 
    1735             :         /*
    1736             :          * Likewise, if we have lost the walwriter process, try to start a new
    1737             :          * one.  But this is needed only in normal operation (else we cannot
    1738             :          * be writing any new WAL).
    1739             :          */
    1740       16616 :         if (WalWriterPID == 0 && pmState == PM_RUN)
    1741           0 :             WalWriterPID = StartWalWriter();
    1742             : 
    1743             :         /*
    1744             :          * If we have lost the autovacuum launcher, try to start a new one. We
    1745             :          * don't want autovacuum to run in binary upgrade mode because
    1746             :          * autovacuum might update relfrozenxid for empty tables before the
    1747             :          * physical files are put in place.
    1748             :          */
    1749       19430 :         if (!IsBinaryUpgrade && AutoVacPID == 0 &&
    1750        5628 :             (AutoVacuumingActive() || start_autovac_launcher) &&
    1751        2586 :             pmState == PM_RUN)
    1752             :         {
    1753           0 :             AutoVacPID = StartAutoVacLauncher();
    1754           0 :             if (AutoVacPID != 0)
    1755           0 :                 start_autovac_launcher = false; /* signal processed */
    1756             :         }
    1757             : 
    1758             :         /* If we have lost the stats collector, try to start a new one */
    1759       16744 :         if (PgStatPID == 0 &&
    1760         256 :             (pmState == PM_RUN || pmState == PM_HOT_STANDBY))
    1761           0 :             PgStatPID = pgstat_start();
    1762             : 
    1763             :         /* If we have lost the archiver, try to start a new one. */
    1764       16616 :         if (PgArchPID == 0 && PgArchStartupAllowed())
    1765           0 :             PgArchPID = pgarch_start();
    1766             : 
    1767             :         /* If we need to signal the autovacuum launcher, do so now */
    1768       16616 :         if (avlauncher_needs_signal)
    1769             :         {
    1770           0 :             avlauncher_needs_signal = false;
    1771           0 :             if (AutoVacPID != 0)
    1772           0 :                 kill(AutoVacPID, SIGUSR2);
    1773             :         }
    1774             : 
    1775             :         /* If we need to start a WAL receiver, try to do that now */
    1776       16616 :         if (WalReceiverRequested)
    1777         152 :             MaybeStartWalReceiver();
    1778             : 
    1779             :         /* Get other worker processes running, if needed */
    1780       16616 :         if (StartWorkerNeeded || HaveCrashedWorker)
    1781        3070 :             maybe_start_bgworkers();
    1782             : 
    1783             : #ifdef HAVE_PTHREAD_IS_THREADED_NP
    1784             : 
    1785             :         /*
    1786             :          * With assertions enabled, check regularly for appearance of
    1787             :          * additional threads.  All builds check at start and exit.
    1788             :          */
    1789             :         Assert(pthread_is_threaded_np() == 0);
    1790             : #endif
    1791             : 
    1792             :         /*
    1793             :          * Lastly, check to see if it's time to do some things that we don't
    1794             :          * want to do every single time through the loop, because they're a
    1795             :          * bit expensive.  Note that there's up to a minute of slop in when
    1796             :          * these tasks will be performed, since DetermineSleepTime() will let
    1797             :          * us sleep at most that long; except for SIGKILL timeout which has
    1798             :          * special-case logic there.
    1799             :          */
    1800       16616 :         now = time(NULL);
    1801             : 
    1802             :         /*
    1803             :          * If we already sent SIGQUIT to children and they are slow to shut
    1804             :          * down, it's time to send them SIGKILL.  This doesn't happen
    1805             :          * normally, but under certain conditions backends can get stuck while
    1806             :          * shutting down.  This is a last measure to get them unwedged.
    1807             :          *
    1808             :          * Note we also do this during recovery from a process crash.
    1809             :          */
    1810       17324 :         if ((Shutdown >= ImmediateShutdown || (FatalError && !SendStop)) &&
    1811        1408 :             AbortStartTime != 0 &&
    1812         700 :             (now - AbortStartTime) >= SIGKILL_CHILDREN_AFTER_SECS)
    1813             :         {
    1814             :             /* We were gentle with them before. Not anymore */
    1815           0 :             TerminateChildren(SIGKILL);
    1816             :             /* reset flag so we don't SIGKILL again */
    1817           0 :             AbortStartTime = 0;
    1818             :         }
    1819             : 
    1820             :         /*
    1821             :          * Once a minute, verify that postmaster.pid hasn't been removed or
    1822             :          * overwritten.  If it has, we force a shutdown.  This avoids having
    1823             :          * postmasters and child processes hanging around after their database
    1824             :          * is gone, and maybe causing problems if a new database cluster is
    1825             :          * created in the same place.  It also provides some protection
    1826             :          * against a DBA foolishly removing postmaster.pid and manually
    1827             :          * starting a new postmaster.  Data corruption is likely to ensue from
    1828             :          * that anyway, but we can minimize the damage by aborting ASAP.
    1829             :          */
    1830       16616 :         if (now - last_lockfile_recheck_time >= 1 * SECS_PER_MINUTE)
    1831             :         {
    1832          10 :             if (!RecheckDataDirLockFile())
    1833             :             {
    1834           0 :                 ereport(LOG,
    1835             :                         (errmsg("performing immediate shutdown because data directory lock file is invalid")));
    1836           0 :                 kill(MyProcPid, SIGQUIT);
    1837             :             }
    1838          10 :             last_lockfile_recheck_time = now;
    1839             :         }
    1840             : 
    1841             :         /*
    1842             :          * Touch Unix socket and lock files every 58 minutes, to ensure that
    1843             :          * they are not removed by overzealous /tmp-cleaning tasks.  We assume
    1844             :          * no one runs cleaners with cutoff times of less than an hour ...
    1845             :          */
    1846       16616 :         if (now - last_touch_time >= 58 * SECS_PER_MINUTE)
    1847             :         {
    1848           0 :             TouchSocketFiles();
    1849           0 :             TouchSocketLockFiles();
    1850           0 :             last_touch_time = now;
    1851             :         }
    1852             :     }
    1853             : }
    1854             : 
    1855             : /*
    1856             :  * Initialise the masks for select() for the ports we are listening on.
    1857             :  * Return the number of sockets to listen on.
    1858             :  */
    1859             : static int
    1860         572 : initMasks(fd_set *rmask)
    1861             : {
    1862         572 :     int         maxsock = -1;
    1863             :     int         i;
    1864             : 
    1865         572 :     FD_ZERO(rmask);
    1866             : 
    1867        1168 :     for (i = 0; i < MAXLISTEN; i++)
    1868             :     {
    1869        1168 :         int         fd = ListenSocket[i];
    1870             : 
    1871        1168 :         if (fd == PGINVALID_SOCKET)
    1872         572 :             break;
    1873         596 :         FD_SET(fd, rmask);
    1874             : 
    1875         596 :         if (fd > maxsock)
    1876         596 :             maxsock = fd;
    1877             :     }
    1878             : 
    1879         572 :     return maxsock + 1;
    1880             : }
    1881             : 
    1882             : 
    1883             : /*
    1884             :  * Read a client's startup packet and do something according to it.
    1885             :  *
    1886             :  * Returns STATUS_OK or STATUS_ERROR, or might call ereport(FATAL) and
    1887             :  * not return at all.
    1888             :  *
    1889             :  * (Note that ereport(FATAL) stuff is sent to the client, so only use it
    1890             :  * if that's what you want.  Return STATUS_ERROR if you don't want to
    1891             :  * send anything to the client, which would typically be appropriate
    1892             :  * if we detect a communications failure.)
    1893             :  *
    1894             :  * Set secure_done when negotiation of an encrypted layer (currently, TLS or
    1895             :  * GSSAPI) is already completed.
    1896             :  */
    1897             : static int
    1898        7114 : ProcessStartupPacket(Port *port, bool secure_done)
    1899             : {
    1900             :     int32       len;
    1901             :     void       *buf;
    1902             :     ProtocolVersion proto;
    1903             :     MemoryContext oldcontext;
    1904             : 
    1905        7114 :     pq_startmsgread();
    1906             : 
    1907             :     /*
    1908             :      * Grab the first byte of the length word separately, so that we can tell
    1909             :      * whether we have no data at all or an incomplete packet.  (This might
    1910             :      * sound inefficient, but it's not really, because of buffering in
    1911             :      * pqcomm.c.)
    1912             :      */
    1913        7114 :     if (pq_getbytes((char *) &len, 1) == EOF)
    1914             :     {
    1915             :         /*
    1916             :          * If we get no data at all, don't clutter the log with a complaint;
    1917             :          * such cases often occur for legitimate reasons.  An example is that
    1918             :          * we might be here after responding to NEGOTIATE_SSL_CODE, and if the
    1919             :          * client didn't like our response, it'll probably just drop the
    1920             :          * connection.  Service-monitoring software also often just opens and
    1921             :          * closes a connection without sending anything.  (So do port
    1922             :          * scanners, which may be less benign, but it's not really our job to
    1923             :          * notice those.)
    1924             :          */
    1925          12 :         return STATUS_ERROR;
    1926             :     }
    1927             : 
    1928        7102 :     if (pq_getbytes(((char *) &len) + 1, 3) == EOF)
    1929             :     {
    1930             :         /* Got a partial length word, so bleat about that */
    1931           0 :         if (!secure_done)
    1932           0 :             ereport(COMMERROR,
    1933             :                     (errcode(ERRCODE_PROTOCOL_VIOLATION),
    1934             :                      errmsg("incomplete startup packet")));
    1935           0 :         return STATUS_ERROR;
    1936             :     }
    1937             : 
    1938        7102 :     len = pg_ntoh32(len);
    1939        7102 :     len -= 4;
    1940             : 
    1941       14204 :     if (len < (int32) sizeof(ProtocolVersion) ||
    1942        7102 :         len > MAX_STARTUP_PACKET_LENGTH)
    1943             :     {
    1944           0 :         ereport(COMMERROR,
    1945             :                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
    1946             :                  errmsg("invalid length of startup packet")));
    1947           0 :         return STATUS_ERROR;
    1948             :     }
    1949             : 
    1950             :     /*
    1951             :      * Allocate at least the size of an old-style startup packet, plus one
    1952             :      * extra byte, and make sure all are zeroes.  This ensures we will have
    1953             :      * null termination of all strings, in both fixed- and variable-length
    1954             :      * packet layouts.
    1955             :      */
    1956        7102 :     if (len <= (int32) sizeof(StartupPacket))
    1957        7102 :         buf = palloc0(sizeof(StartupPacket) + 1);
    1958             :     else
    1959           0 :         buf = palloc0(len + 1);
    1960             : 
    1961        7102 :     if (pq_getbytes(buf, len) == EOF)
    1962             :     {
    1963           0 :         ereport(COMMERROR,
    1964             :                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
    1965             :                  errmsg("incomplete startup packet")));
    1966           0 :         return STATUS_ERROR;
    1967             :     }
    1968        7102 :     pq_endmsgread();
    1969             : 
    1970             :     /*
    1971             :      * The first field is either a protocol version number or a special
    1972             :      * request code.
    1973             :      */
    1974        7102 :     port->proto = proto = pg_ntoh32(*((ProtocolVersion *) buf));
    1975             : 
    1976        7102 :     if (proto == CANCEL_REQUEST_CODE)
    1977             :     {
    1978           2 :         processCancelRequest(port, buf);
    1979             :         /* Not really an error, but we don't want to proceed further */
    1980           2 :         return STATUS_ERROR;
    1981             :     }
    1982             : 
    1983        7100 :     if (proto == NEGOTIATE_SSL_CODE && !secure_done)
    1984             :     {
    1985             :         char        SSLok;
    1986             : 
    1987             : #ifdef USE_SSL
    1988             :         /* No SSL when disabled or on Unix sockets */
    1989         378 :         if (!LoadedSSL || IS_AF_UNIX(port->laddr.addr.ss_family))
    1990         294 :             SSLok = 'N';
    1991             :         else
    1992          84 :             SSLok = 'S';        /* Support for SSL */
    1993             : #else
    1994             :         SSLok = 'N';            /* No support for SSL */
    1995             : #endif
    1996             : 
    1997             : retry1:
    1998         378 :         if (send(port->sock, &SSLok, 1, 0) != 1)
    1999             :         {
    2000           0 :             if (errno == EINTR)
    2001           0 :                 goto retry1;    /* if interrupted, just retry */
    2002           0 :             ereport(COMMERROR,
    2003             :                     (errcode_for_socket_access(),
    2004             :                      errmsg("failed to send SSL negotiation response: %m")));
    2005           0 :             return STATUS_ERROR;    /* close the connection */
    2006             :         }
    2007             : 
    2008             : #ifdef USE_SSL
    2009         378 :         if (SSLok == 'S' && secure_open_server(port) == -1)
    2010          20 :             return STATUS_ERROR;
    2011             : #endif
    2012             :         /* regular startup packet, cancel, etc packet should follow... */
    2013             :         /* but not another SSL negotiation request */
    2014         358 :         return ProcessStartupPacket(port, true);
    2015             :     }
    2016        6722 :     else if (proto == NEGOTIATE_GSS_CODE && !secure_done)
    2017             :     {
    2018           0 :         char        GSSok = 'N';
    2019             : #ifdef ENABLE_GSS
    2020             :         /* No GSSAPI encryption when on Unix socket */
    2021             :         if (!IS_AF_UNIX(port->laddr.addr.ss_family))
    2022             :             GSSok = 'G';
    2023             : #endif
    2024             : 
    2025           0 :         while (send(port->sock, &GSSok, 1, 0) != 1)
    2026             :         {
    2027           0 :             if (errno == EINTR)
    2028           0 :                 continue;
    2029           0 :             ereport(COMMERROR,
    2030             :                     (errcode_for_socket_access(),
    2031             :                      errmsg("failed to send GSSAPI negotiation response: %m")));
    2032           0 :             return STATUS_ERROR;    /* close the connection */
    2033             :         }
    2034             : 
    2035             : #ifdef ENABLE_GSS
    2036             :         if (GSSok == 'G' && secure_open_gssapi(port) == -1)
    2037             :             return STATUS_ERROR;
    2038             : #endif
    2039             :         /* Won't ever see more than one negotiation request */
    2040           0 :         return ProcessStartupPacket(port, true);
    2041             :     }
    2042             : 
    2043             :     /* Could add additional special packet types here */
    2044             : 
    2045             :     /*
    2046             :      * Set FrontendProtocol now so that ereport() knows what format to send if
    2047             :      * we fail during startup.
    2048             :      */
    2049        6722 :     FrontendProtocol = proto;
    2050             : 
    2051             :     /* Check that the major protocol version is in range. */
    2052       13444 :     if (PG_PROTOCOL_MAJOR(proto) < PG_PROTOCOL_MAJOR(PG_PROTOCOL_EARLIEST) ||
    2053        6722 :         PG_PROTOCOL_MAJOR(proto) > PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST))
    2054           0 :         ereport(FATAL,
    2055             :                 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
    2056             :                  errmsg("unsupported frontend protocol %u.%u: server supports %u.0 to %u.%u",
    2057             :                         PG_PROTOCOL_MAJOR(proto), PG_PROTOCOL_MINOR(proto),
    2058             :                         PG_PROTOCOL_MAJOR(PG_PROTOCOL_EARLIEST),
    2059             :                         PG_PROTOCOL_MAJOR(PG_PROTOCOL_LATEST),
    2060             :                         PG_PROTOCOL_MINOR(PG_PROTOCOL_LATEST))));
    2061             : 
    2062             :     /*
    2063             :      * Now fetch parameters out of startup packet and save them into the Port
    2064             :      * structure.  All data structures attached to the Port struct must be
    2065             :      * allocated in TopMemoryContext so that they will remain available in a
    2066             :      * running backend (even after PostmasterContext is destroyed).  We need
    2067             :      * not worry about leaking this storage on failure, since we aren't in the
    2068             :      * postmaster process anymore.
    2069             :      */
    2070        6722 :     oldcontext = MemoryContextSwitchTo(TopMemoryContext);
    2071             : 
    2072        6722 :     if (PG_PROTOCOL_MAJOR(proto) >= 3)
    2073             :     {
    2074        6722 :         int32       offset = sizeof(ProtocolVersion);
    2075        6722 :         List       *unrecognized_protocol_options = NIL;
    2076             : 
    2077             :         /*
    2078             :          * Scan packet body for name/option pairs.  We can assume any string
    2079             :          * beginning within the packet body is null-terminated, thanks to
    2080             :          * zeroing extra byte above.
    2081             :          */
    2082        6722 :         port->guc_options = NIL;
    2083             : 
    2084       44532 :         while (offset < len)
    2085             :         {
    2086       37810 :             char       *nameptr = ((char *) buf) + offset;
    2087             :             int32       valoffset;
    2088             :             char       *valptr;
    2089             : 
    2090       37810 :             if (*nameptr == '\0')
    2091        6722 :                 break;          /* found packet terminator */
    2092       31088 :             valoffset = offset + strlen(nameptr) + 1;
    2093       31088 :             if (valoffset >= len)
    2094           0 :                 break;          /* missing value, will complain below */
    2095       31088 :             valptr = ((char *) buf) + valoffset;
    2096             : 
    2097       31088 :             if (strcmp(nameptr, "database") == 0)
    2098        6722 :                 port->database_name = pstrdup(valptr);
    2099       24366 :             else if (strcmp(nameptr, "user") == 0)
    2100        6722 :                 port->user_name = pstrdup(valptr);
    2101       17644 :             else if (strcmp(nameptr, "options") == 0)
    2102        3318 :                 port->cmdline_options = pstrdup(valptr);
    2103       14326 :             else if (strcmp(nameptr, "replication") == 0)
    2104             :             {
    2105             :                 /*
    2106             :                  * Due to backward compatibility concerns the replication
    2107             :                  * parameter is a hybrid beast which allows the value to be
    2108             :                  * either boolean or the string 'database'. The latter
    2109             :                  * connects to a specific database which is e.g. required for
    2110             :                  * logical decoding while.
    2111             :                  */
    2112         474 :                 if (strcmp(valptr, "database") == 0)
    2113             :                 {
    2114         180 :                     am_walsender = true;
    2115         180 :                     am_db_walsender = true;
    2116             :                 }
    2117         294 :                 else if (!parse_bool(valptr, &am_walsender))
    2118           0 :                     ereport(FATAL,
    2119             :                             (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    2120             :                              errmsg("invalid value for parameter \"%s\": \"%s\"",
    2121             :                                     "replication",
    2122             :                                     valptr),
    2123             :                              errhint("Valid values are: \"false\", 0, \"true\", 1, \"database\".")));
    2124             :             }
    2125       13852 :             else if (strncmp(nameptr, "_pq_.", 5) == 0)
    2126             :             {
    2127             :                 /*
    2128             :                  * Any option beginning with _pq_. is reserved for use as a
    2129             :                  * protocol-level option, but at present no such options are
    2130             :                  * defined.
    2131             :                  */
    2132           0 :                 unrecognized_protocol_options =
    2133           0 :                     lappend(unrecognized_protocol_options, pstrdup(nameptr));
    2134             :             }
    2135             :             else
    2136             :             {
    2137             :                 /* Assume it's a generic GUC option */
    2138       13852 :                 port->guc_options = lappend(port->guc_options,
    2139       13852 :                                             pstrdup(nameptr));
    2140       13852 :                 port->guc_options = lappend(port->guc_options,
    2141       13852 :                                             pstrdup(valptr));
    2142             : 
    2143             :                 /*
    2144             :                  * Copy application_name to port if we come across it.  This
    2145             :                  * is done so we can log the application_name in the
    2146             :                  * connection authorization message.  Note that the GUC would
    2147             :                  * be used but we haven't gone through GUC setup yet.
    2148             :                  */
    2149       13852 :                 if (strcmp(nameptr, "application_name") == 0)
    2150             :                 {
    2151        6634 :                     char       *tmp_app_name = pstrdup(valptr);
    2152             : 
    2153        6634 :                     pg_clean_ascii(tmp_app_name);
    2154             : 
    2155        6634 :                     port->application_name = tmp_app_name;
    2156             :                 }
    2157             :             }
    2158       31088 :             offset = valoffset + strlen(valptr) + 1;
    2159             :         }
    2160             : 
    2161             :         /*
    2162             :          * If we didn't find a packet terminator exactly at the end of the
    2163             :          * given packet length, complain.
    2164             :          */
    2165        6722 :         if (offset != len - 1)
    2166           0 :             ereport(FATAL,
    2167             :                     (errcode(ERRCODE_PROTOCOL_VIOLATION),
    2168             :                      errmsg("invalid startup packet layout: expected terminator as last byte")));
    2169             : 
    2170             :         /*
    2171             :          * If the client requested a newer protocol version or if the client
    2172             :          * requested any protocol options we didn't recognize, let them know
    2173             :          * the newest minor protocol version we do support and the names of
    2174             :          * any unrecognized options.
    2175             :          */
    2176        6722 :         if (PG_PROTOCOL_MINOR(proto) > PG_PROTOCOL_MINOR(PG_PROTOCOL_LATEST) ||
    2177             :             unrecognized_protocol_options != NIL)
    2178           0 :             SendNegotiateProtocolVersion(unrecognized_protocol_options);
    2179             :     }
    2180             :     else
    2181             :     {
    2182             :         /*
    2183             :          * Get the parameters from the old-style, fixed-width-fields startup
    2184             :          * packet as C strings.  The packet destination was cleared first so a
    2185             :          * short packet has zeros silently added.  We have to be prepared to
    2186             :          * truncate the pstrdup result for oversize fields, though.
    2187             :          */
    2188           0 :         StartupPacket *packet = (StartupPacket *) buf;
    2189             : 
    2190           0 :         port->database_name = pstrdup(packet->database);
    2191           0 :         if (strlen(port->database_name) > sizeof(packet->database))
    2192           0 :             port->database_name[sizeof(packet->database)] = '\0';
    2193           0 :         port->user_name = pstrdup(packet->user);
    2194           0 :         if (strlen(port->user_name) > sizeof(packet->user))
    2195           0 :             port->user_name[sizeof(packet->user)] = '\0';
    2196           0 :         port->cmdline_options = pstrdup(packet->options);
    2197           0 :         if (strlen(port->cmdline_options) > sizeof(packet->options))
    2198           0 :             port->cmdline_options[sizeof(packet->options)] = '\0';
    2199           0 :         port->guc_options = NIL;
    2200             :     }
    2201             : 
    2202             :     /* Check a user name was given. */
    2203        6722 :     if (port->user_name == NULL || port->user_name[0] == '\0')
    2204           0 :         ereport(FATAL,
    2205             :                 (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
    2206             :                  errmsg("no PostgreSQL user name specified in startup packet")));
    2207             : 
    2208             :     /* The database defaults to the user name. */
    2209        6722 :     if (port->database_name == NULL || port->database_name[0] == '\0')
    2210           0 :         port->database_name = pstrdup(port->user_name);
    2211             : 
    2212        6722 :     if (Db_user_namespace)
    2213             :     {
    2214             :         /*
    2215             :          * If user@, it is a global user, remove '@'. We only want to do this
    2216             :          * if there is an '@' at the end and no earlier in the user string or
    2217             :          * they may fake as a local user of another database attaching to this
    2218             :          * database.
    2219             :          */
    2220           0 :         if (strchr(port->user_name, '@') ==
    2221           0 :             port->user_name + strlen(port->user_name) - 1)
    2222           0 :             *strchr(port->user_name, '@') = '\0';
    2223             :         else
    2224             :         {
    2225             :             /* Append '@' and dbname */
    2226           0 :             port->user_name = psprintf("%s@%s", port->user_name, port->database_name);
    2227             :         }
    2228             :     }
    2229             : 
    2230             :     /*
    2231             :      * Truncate given database and user names to length of a Postgres name.
    2232             :      * This avoids lookup failures when overlength names are given.
    2233             :      */
    2234        6722 :     if (strlen(port->database_name) >= NAMEDATALEN)
    2235           0 :         port->database_name[NAMEDATALEN - 1] = '\0';
    2236        6722 :     if (strlen(port->user_name) >= NAMEDATALEN)
    2237           0 :         port->user_name[NAMEDATALEN - 1] = '\0';
    2238             : 
    2239             :     /*
    2240             :      * Normal walsender backends, e.g. for streaming replication, are not
    2241             :      * connected to a particular database. But walsenders used for logical
    2242             :      * replication need to connect to a specific database. We allow streaming
    2243             :      * replication commands to be issued even if connected to a database as it
    2244             :      * can make sense to first make a basebackup and then stream changes
    2245             :      * starting from that.
    2246             :      */
    2247        6722 :     if (am_walsender && !am_db_walsender)
    2248         294 :         port->database_name[0] = '\0';
    2249             : 
    2250             :     /*
    2251             :      * Done putting stuff in TopMemoryContext.
    2252             :      */
    2253        6722 :     MemoryContextSwitchTo(oldcontext);
    2254             : 
    2255             :     /*
    2256             :      * If we're going to reject the connection due to database state, say so
    2257             :      * now instead of wasting cycles on an authentication exchange. (This also
    2258             :      * allows a pg_ping utility to be written.)
    2259             :      */
    2260        6722 :     switch (port->canAcceptConnections)
    2261             :     {
    2262             :         case CAC_STARTUP:
    2263          76 :             ereport(FATAL,
    2264             :                     (errcode(ERRCODE_CANNOT_CONNECT_NOW),
    2265             :                      errmsg("the database system is starting up")));
    2266             :             break;
    2267             :         case CAC_SHUTDOWN:
    2268           0 :             ereport(FATAL,
    2269             :                     (errcode(ERRCODE_CANNOT_CONNECT_NOW),
    2270             :                      errmsg("the database system is shutting down")));
    2271             :             break;
    2272             :         case CAC_RECOVERY:
    2273           4 :             ereport(FATAL,
    2274             :                     (errcode(ERRCODE_CANNOT_CONNECT_NOW),
    2275             :                      errmsg("the database system is in recovery mode")));
    2276             :             break;
    2277             :         case CAC_TOOMANY:
    2278           0 :             ereport(FATAL,
    2279             :                     (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
    2280             :                      errmsg("sorry, too many clients already")));
    2281             :             break;
    2282             :         case CAC_WAITBACKUP:
    2283             :             /* OK for now, will check in InitPostgres */
    2284           0 :             break;
    2285             :         case CAC_OK:
    2286        6642 :             break;
    2287             :     }
    2288             : 
    2289        6642 :     return STATUS_OK;
    2290             : }
    2291             : 
    2292             : /*
    2293             :  * Send a NegotiateProtocolVersion to the client.  This lets the client know
    2294             :  * that they have requested a newer minor protocol version than we are able
    2295             :  * to speak.  We'll speak the highest version we know about; the client can,
    2296             :  * of course, abandon the connection if that's a problem.
    2297             :  *
    2298             :  * We also include in the response a list of protocol options we didn't
    2299             :  * understand.  This allows clients to include optional parameters that might
    2300             :  * be present either in newer protocol versions or third-party protocol
    2301             :  * extensions without fear of having to reconnect if those options are not
    2302             :  * understood, while at the same time making certain that the client is aware
    2303             :  * of which options were actually accepted.
    2304             :  */
    2305             : static void
    2306           0 : SendNegotiateProtocolVersion(List *unrecognized_protocol_options)
    2307             : {
    2308             :     StringInfoData buf;
    2309             :     ListCell   *lc;
    2310             : 
    2311           0 :     pq_beginmessage(&buf, 'v'); /* NegotiateProtocolVersion */
    2312           0 :     pq_sendint32(&buf, PG_PROTOCOL_LATEST);
    2313           0 :     pq_sendint32(&buf, list_length(unrecognized_protocol_options));
    2314           0 :     foreach(lc, unrecognized_protocol_options)
    2315           0 :         pq_sendstring(&buf, lfirst(lc));
    2316           0 :     pq_endmessage(&buf);
    2317             : 
    2318             :     /* no need to flush, some other message will follow */
    2319           0 : }
    2320             : 
    2321             : /*
    2322             :  * The client has sent a cancel request packet, not a normal
    2323             :  * start-a-new-connection packet.  Perform the necessary processing.
    2324             :  * Nothing is sent back to the client.
    2325             :  */
    2326             : static void
    2327           2 : processCancelRequest(Port *port, void *pkt)
    2328             : {
    2329           2 :     CancelRequestPacket *canc = (CancelRequestPacket *) pkt;
    2330             :     int         backendPID;
    2331             :     int32       cancelAuthCode;
    2332             :     Backend    *bp;
    2333             : 
    2334             : #ifndef EXEC_BACKEND
    2335             :     dlist_iter  iter;
    2336             : #else
    2337             :     int         i;
    2338             : #endif
    2339             : 
    2340           2 :     backendPID = (int) pg_ntoh32(canc->backendPID);
    2341           2 :     cancelAuthCode = (int32) pg_ntoh32(canc->cancelAuthCode);
    2342             : 
    2343             :     /*
    2344             :      * See if we have a matching backend.  In the EXEC_BACKEND case, we can no
    2345             :      * longer access the postmaster's own backend list, and must rely on the
    2346             :      * duplicate array in shared memory.
    2347             :      */
    2348             : #ifndef EXEC_BACKEND
    2349           2 :     dlist_foreach(iter, &BackendList)
    2350             :     {
    2351           2 :         bp = dlist_container(Backend, elem, iter.cur);
    2352             : #else
    2353             :     for (i = MaxLivePostmasterChildren() - 1; i >= 0; i--)
    2354             :     {
    2355             :         bp = (Backend *) &ShmemBackendArray[i];
    2356             : #endif
    2357           2 :         if (bp->pid == backendPID)
    2358             :         {
    2359           2 :             if (bp->cancel_key == cancelAuthCode)
    2360             :             {
    2361             :                 /* Found a match; signal that backend to cancel current op */
    2362           2 :                 ereport(DEBUG2,
    2363             :                         (errmsg_internal("processing cancel request: sending SIGINT to process %d",
    2364             :                                          backendPID)));
    2365           2 :                 signal_child(bp->pid, SIGINT);
    2366             :             }
    2367             :             else
    2368             :                 /* Right PID, wrong key: no way, Jose */
    2369           0 :                 ereport(LOG,
    2370             :                         (errmsg("wrong key in cancel request for process %d",
    2371             :                                 backendPID)));
    2372           2 :             return;
    2373             :         }
    2374             : #ifndef EXEC_BACKEND            /* make GNU Emacs 26.1 see brace balance */
    2375             :     }
    2376             : #else
    2377             :     }
    2378             : #endif
    2379             : 
    2380             :     /* No matching backend */
    2381           0 :     ereport(LOG,
    2382             :             (errmsg("PID %d in cancel request did not match any process",
    2383             :                     backendPID)));
    2384             : }
    2385             : 
    2386             : /*
    2387             :  * canAcceptConnections --- check to see if database state allows connections.
    2388             :  */
    2389             : static CAC_state
    2390        6930 : canAcceptConnections(void)
    2391             : {
    2392        6930 :     CAC_state   result = CAC_OK;
    2393             : 
    2394             :     /*
    2395             :      * Can't start backends when in startup/shutdown/inconsistent recovery
    2396             :      * state.
    2397             :      *
    2398             :      * In state PM_WAIT_BACKUP only superusers can connect (this must be
    2399             :      * allowed so that a superuser can end online backup mode); we return
    2400             :      * CAC_WAITBACKUP code to indicate that this must be checked later. Note
    2401             :      * that neither CAC_OK nor CAC_WAITBACKUP can safely be returned until we
    2402             :      * have checked for too many children.
    2403             :      */
    2404        6930 :     if (pmState != PM_RUN)
    2405             :     {
    2406         326 :         if (pmState == PM_WAIT_BACKUP)
    2407           0 :             result = CAC_WAITBACKUP;    /* allow superusers only */
    2408         326 :         else if (Shutdown > NoShutdown)
    2409           0 :             return CAC_SHUTDOWN;    /* shutdown is pending */
    2410         648 :         else if (!FatalError &&
    2411         568 :                  (pmState == PM_STARTUP ||
    2412         246 :                   pmState == PM_RECOVERY))
    2413          76 :             return CAC_STARTUP; /* normal startup */
    2414         496 :         else if (!FatalError &&
    2415         246 :                  pmState == PM_HOT_STANDBY)
    2416         246 :             result = CAC_OK;    /* connection OK during hot standby */
    2417             :         else
    2418           4 :             return CAC_RECOVERY;    /* else must be crash recovery */
    2419             :     }
    2420             : 
    2421             :     /*
    2422             :      * Don't start too many children.
    2423             :      *
    2424             :      * We allow more connections than we can have backends here because some
    2425             :      * might still be authenticating; they might fail auth, or some existing
    2426             :      * backend might exit before the auth cycle is completed. The exact
    2427             :      * MaxBackends limit is enforced when a new backend tries to join the
    2428             :      * shared-inval backend array.
    2429             :      *
    2430             :      * The limit here must match the sizes of the per-child-process arrays;
    2431             :      * see comments for MaxLivePostmasterChildren().
    2432             :      */
    2433        6850 :     if (CountChildren(BACKEND_TYPE_ALL) >= MaxLivePostmasterChildren())
    2434           0 :         result = CAC_TOOMANY;
    2435             : 
    2436        6850 :     return result;
    2437             : }
    2438             : 
    2439             : 
    2440             : /*
    2441             :  * ConnCreate -- create a local connection data structure
    2442             :  *
    2443             :  * Returns NULL on failure, other than out-of-memory which is fatal.
    2444             :  */
    2445             : static Port *
    2446        6870 : ConnCreate(int serverFd)
    2447             : {
    2448             :     Port       *port;
    2449             : 
    2450        6870 :     if (!(port = (Port *) calloc(1, sizeof(Port))))
    2451             :     {
    2452           0 :         ereport(LOG,
    2453             :                 (errcode(ERRCODE_OUT_OF_MEMORY),
    2454             :                  errmsg("out of memory")));
    2455           0 :         ExitPostmaster(1);
    2456             :     }
    2457             : 
    2458        6870 :     if (StreamConnection(serverFd, port) != STATUS_OK)
    2459             :     {
    2460           0 :         if (port->sock != PGINVALID_SOCKET)
    2461           0 :             StreamClose(port->sock);
    2462           0 :         ConnFree(port);
    2463           0 :         return NULL;
    2464             :     }
    2465             : 
    2466             :     /*
    2467             :      * Allocate GSSAPI specific state struct
    2468             :      */
    2469             : #ifndef EXEC_BACKEND
    2470             : #if defined(ENABLE_GSS) || defined(ENABLE_SSPI)
    2471             :     port->gss = (pg_gssinfo *) calloc(1, sizeof(pg_gssinfo));
    2472             :     if (!port->gss)
    2473             :     {
    2474             :         ereport(LOG,
    2475             :                 (errcode(ERRCODE_OUT_OF_MEMORY),
    2476             :                  errmsg("out of memory")));
    2477             :         ExitPostmaster(1);
    2478             :     }
    2479             : #endif
    2480             : #endif
    2481             : 
    2482        6870 :     return port;
    2483             : }
    2484             : 
    2485             : 
    2486             : /*
    2487             :  * ConnFree -- free a local connection data structure
    2488             :  */
    2489             : static void
    2490        6868 : ConnFree(Port *conn)
    2491             : {
    2492             : #ifdef USE_SSL
    2493        6868 :     secure_close(conn);
    2494             : #endif
    2495        6868 :     if (conn->gss)
    2496           0 :         free(conn->gss);
    2497        6868 :     free(conn);
    2498        6868 : }
    2499             : 
    2500             : 
    2501             : /*
    2502             :  * ClosePostmasterPorts -- close all the postmaster's open sockets
    2503             :  *
    2504             :  * This is called during child process startup to release file descriptors
    2505             :  * that are not needed by that child process.  The postmaster still has
    2506             :  * them open, of course.
    2507             :  *
    2508             :  * Note: we pass am_syslogger as a boolean because we don't want to set
    2509             :  * the global variable yet when this is called.
    2510             :  */
    2511             : void
    2512       11714 : ClosePostmasterPorts(bool am_syslogger)
    2513             : {
    2514             :     int         i;
    2515             : 
    2516             : #ifndef WIN32
    2517             : 
    2518             :     /*
    2519             :      * Close the write end of postmaster death watch pipe. It's important to
    2520             :      * do this as early as possible, so that if postmaster dies, others won't
    2521             :      * think that it's still running because we're holding the pipe open.
    2522             :      */
    2523       11714 :     if (close(postmaster_alive_fds[POSTMASTER_FD_OWN]))
    2524           0 :         ereport(FATAL,
    2525             :                 (errcode_for_file_access(),
    2526             :                  errmsg_internal("could not close postmaster death monitoring pipe in child process: %m")));
    2527       11714 :     postmaster_alive_fds[POSTMASTER_FD_OWN] = -1;
    2528             : #endif
    2529             : 
    2530             :     /* Close the listen sockets */
    2531      761410 :     for (i = 0; i < MAXLISTEN; i++)
    2532             :     {
    2533      749696 :         if (ListenSocket[i] != PGINVALID_SOCKET)
    2534             :         {
    2535       12246 :             StreamClose(ListenSocket[i]);
    2536       12246 :             ListenSocket[i] = PGINVALID_SOCKET;
    2537             :         }
    2538             :     }
    2539             : 
    2540             :     /* If using syslogger, close the read side of the pipe */
    2541       11714 :     if (!am_syslogger)
    2542             :     {
    2543             : #ifndef WIN32
    2544       11712 :         if (syslogPipe[0] >= 0)
    2545          18 :             close(syslogPipe[0]);
    2546       11712 :         syslogPipe[0] = -1;
    2547             : #else
    2548             :         if (syslogPipe[0])
    2549             :             CloseHandle(syslogPipe[0]);
    2550             :         syslogPipe[0] = 0;
    2551             : #endif
    2552             :     }
    2553             : 
    2554             : #ifdef USE_BONJOUR
    2555             :     /* If using Bonjour, close the connection to the mDNS daemon */
    2556             :     if (bonjour_sdref)
    2557             :         close(DNSServiceRefSockFD(bonjour_sdref));
    2558             : #endif
    2559       11714 : }
    2560             : 
    2561             : 
    2562             : /*
    2563             :  * InitProcessGlobals -- set MyProcPid, MyStartTime[stamp], random seeds
    2564             :  *
    2565             :  * Called early in the postmaster and every backend.
    2566             :  */
    2567             : void
    2568       13568 : InitProcessGlobals(void)
    2569             : {
    2570             :     unsigned int rseed;
    2571             : 
    2572       13568 :     MyProcPid = getpid();
    2573       13568 :     MyStartTimestamp = GetCurrentTimestamp();
    2574       13568 :     MyStartTime = timestamptz_to_time_t(MyStartTimestamp);
    2575             : 
    2576             :     /*
    2577             :      * Set a different seed for random() in every process.  We want something
    2578             :      * unpredictable, so if possible, use high-quality random bits for the
    2579             :      * seed.  Otherwise, fall back to a seed based on timestamp and PID.
    2580             :      */
    2581       13568 :     if (!pg_strong_random(&rseed, sizeof(rseed)))
    2582             :     {
    2583             :         /*
    2584             :          * Since PIDs and timestamps tend to change more frequently in their
    2585             :          * least significant bits, shift the timestamp left to allow a larger
    2586             :          * total number of seeds in a given time period.  Since that would
    2587             :          * leave only 20 bits of the timestamp that cycle every ~1 second,
    2588             :          * also mix in some higher bits.
    2589             :          */
    2590           0 :         rseed = ((uint64) MyProcPid) ^
    2591           0 :             ((uint64) MyStartTimestamp << 12) ^
    2592           0 :             ((uint64) MyStartTimestamp >> 20);
    2593             :     }
    2594       13568 :     srandom(rseed);
    2595       13568 : }
    2596             : 
    2597             : 
    2598             : /*
    2599             :  * reset_shared -- reset shared memory and semaphores
    2600             :  */
    2601             : static void
    2602         578 : reset_shared(int port)
    2603             : {
    2604             :     /*
    2605             :      * Create or re-create shared memory and semaphores.
    2606             :      *
    2607             :      * Note: in each "cycle of life" we will normally assign the same IPC keys
    2608             :      * (if using SysV shmem and/or semas), since the port number is used to
    2609             :      * determine IPC keys.  This helps ensure that we will clean up dead IPC
    2610             :      * objects if the postmaster crashes and is restarted.
    2611             :      */
    2612         578 :     CreateSharedMemoryAndSemaphores(port);
    2613         576 : }
    2614             : 
    2615             : 
    2616             : /*
    2617             :  * SIGHUP -- reread config files, and tell children to do same
    2618             :  */
    2619             : static void
    2620          48 : SIGHUP_handler(SIGNAL_ARGS)
    2621             : {
    2622          48 :     int         save_errno = errno;
    2623             : 
    2624          48 :     PG_SETMASK(&BlockSig);
    2625             : 
    2626          48 :     if (Shutdown <= SmartShutdown)
    2627             :     {
    2628          48 :         ereport(LOG,
    2629             :                 (errmsg("received SIGHUP, reloading configuration files")));
    2630          48 :         ProcessConfigFile(PGC_SIGHUP);
    2631          48 :         SignalChildren(SIGHUP);
    2632          48 :         if (StartupPID != 0)
    2633          10 :             signal_child(StartupPID, SIGHUP);
    2634          48 :         if (BgWriterPID != 0)
    2635          48 :             signal_child(BgWriterPID, SIGHUP);
    2636          48 :         if (CheckpointerPID != 0)
    2637          48 :             signal_child(CheckpointerPID, SIGHUP);
    2638          48 :         if (WalWriterPID != 0)
    2639          38 :             signal_child(WalWriterPID, SIGHUP);
    2640          48 :         if (WalReceiverPID != 0)
    2641          10 :             signal_child(WalReceiverPID, SIGHUP);
    2642          48 :         if (AutoVacPID != 0)
    2643          38 :             signal_child(AutoVacPID, SIGHUP);
    2644          48 :         if (PgArchPID != 0)
    2645           0 :             signal_child(PgArchPID, SIGHUP);
    2646          48 :         if (SysLoggerPID != 0)
    2647           0 :             signal_child(SysLoggerPID, SIGHUP);
    2648          48 :         if (PgStatPID != 0)
    2649          48 :             signal_child(PgStatPID, SIGHUP);
    2650             : 
    2651             :         /* Reload authentication config files too */
    2652          48 :         if (!load_hba())
    2653           0 :             ereport(LOG,
    2654             :             /* translator: %s is a configuration file */
    2655             :                     (errmsg("%s was not reloaded", "pg_hba.conf")));
    2656             : 
    2657          48 :         if (!load_ident())
    2658           0 :             ereport(LOG,
    2659             :                     (errmsg("%s was not reloaded", "pg_ident.conf")));
    2660             : 
    2661             : #ifdef USE_SSL
    2662             :         /* Reload SSL configuration as well */
    2663          48 :         if (EnableSSL)
    2664             :         {
    2665           0 :             if (secure_initialize(false) == 0)
    2666           0 :                 LoadedSSL = true;
    2667             :             else
    2668           0 :                 ereport(LOG,
    2669             :                         (errmsg("SSL configuration was not reloaded")));
    2670             :         }
    2671             :         else
    2672             :         {
    2673          48 :             secure_destroy();
    2674          48 :             LoadedSSL = false;
    2675             :         }
    2676             : #endif
    2677             : 
    2678             : #ifdef EXEC_BACKEND
    2679             :         /* Update the starting-point file for future children */
    2680             :         write_nondefault_variables(PGC_SIGHUP);
    2681             : #endif
    2682             :     }
    2683             : 
    2684          48 :     PG_SETMASK(&UnBlockSig);
    2685             : 
    2686          48 :     errno = save_errno;
    2687          48 : }
    2688             : 
    2689             : 
    2690             : /*
    2691             :  * pmdie -- signal handler for processing various postmaster signals.
    2692             :  */
    2693             : static void
    2694         568 : pmdie(SIGNAL_ARGS)
    2695             : {
    2696         568 :     int         save_errno = errno;
    2697             : 
    2698         568 :     PG_SETMASK(&BlockSig);
    2699             : 
    2700         568 :     ereport(DEBUG2,
    2701             :             (errmsg_internal("postmaster received signal %d",
    2702             :                              postgres_signal_arg)));
    2703             : 
    2704         568 :     switch (postgres_signal_arg)
    2705             :     {
    2706             :         case SIGTERM:
    2707             : 
    2708             :             /*
    2709             :              * Smart Shutdown:
    2710             :              *
    2711             :              * Wait for children to end their work, then shut down.
    2712             :              */
    2713           8 :             if (Shutdown >= SmartShutdown)
    2714           0 :                 break;
    2715           8 :             Shutdown = SmartShutdown;
    2716           8 :             ereport(LOG,
    2717             :                     (errmsg("received smart shutdown request")));
    2718             : 
    2719             :             /* Report status */
    2720           8 :             AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STOPPING);
    2721             : #ifdef USE_SYSTEMD
    2722             :             sd_notify(0, "STOPPING=1");
    2723             : #endif
    2724             : 
    2725           8 :             if (pmState == PM_RUN || pmState == PM_RECOVERY ||
    2726           0 :                 pmState == PM_HOT_STANDBY || pmState == PM_STARTUP)
    2727             :             {
    2728             :                 /* autovac workers are told to shut down immediately */
    2729             :                 /* and bgworkers too; does this need tweaking? */
    2730           8 :                 SignalSomeChildren(SIGTERM,
    2731             :                                    BACKEND_TYPE_AUTOVAC | BACKEND_TYPE_BGWORKER);
    2732             :                 /* and the autovac launcher too */
    2733           8 :                 if (AutoVacPID != 0)
    2734           0 :                     signal_child(AutoVacPID, SIGTERM);
    2735             :                 /* and the bgwriter too */
    2736           8 :                 if (BgWriterPID != 0)
    2737           8 :                     signal_child(BgWriterPID, SIGTERM);
    2738             :                 /* and the walwriter too */
    2739           8 :                 if (WalWriterPID != 0)
    2740           8 :                     signal_child(WalWriterPID, SIGTERM);
    2741             : 
    2742             :                 /*
    2743             :                  * If we're in recovery, we can't kill the startup process
    2744             :                  * right away, because at present doing so does not release
    2745             :                  * its locks.  We might want to change this in a future
    2746             :                  * release.  For the time being, the PM_WAIT_READONLY state
    2747             :                  * indicates that we're waiting for the regular (read only)
    2748             :                  * backends to die off; once they do, we'll kill the startup
    2749             :                  * and walreceiver processes.
    2750             :                  */
    2751          16 :                 pmState = (pmState == PM_RUN) ?
    2752           8 :                     PM_WAIT_BACKUP : PM_WAIT_READONLY;
    2753             :             }
    2754             : 
    2755             :             /*
    2756             :              * Now wait for online backup mode to end and backends to exit. If
    2757             :              * that is already the case, PostmasterStateMachine will take the
    2758             :              * next step.
    2759             :              */
    2760           8 :             PostmasterStateMachine();
    2761           8 :             break;
    2762             : 
    2763             :         case SIGINT:
    2764             : 
    2765             :             /*
    2766             :              * Fast Shutdown:
    2767             :              *
    2768             :              * Abort all children with SIGTERM (rollback active transactions
    2769             :              * and exit) and shut down when they are gone.
    2770             :              */
    2771         368 :             if (Shutdown >= FastShutdown)
    2772           0 :                 break;
    2773         368 :             Shutdown = FastShutdown;
    2774         368 :             ereport(LOG,
    2775             :                     (errmsg("received fast shutdown request")));
    2776             : 
    2777             :             /* Report status */
    2778         368 :             AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STOPPING);
    2779             : #ifdef USE_SYSTEMD
    2780             :             sd_notify(0, "STOPPING=1");
    2781             : #endif
    2782             : 
    2783         368 :             if (StartupPID != 0)
    2784          22 :                 signal_child(StartupPID, SIGTERM);
    2785         368 :             if (BgWriterPID != 0)
    2786         368 :                 signal_child(BgWriterPID, SIGTERM);
    2787         368 :             if (WalReceiverPID != 0)
    2788          18 :                 signal_child(WalReceiverPID, SIGTERM);
    2789         368 :             if (pmState == PM_STARTUP || pmState == PM_RECOVERY)
    2790             :             {
    2791           0 :                 SignalSomeChildren(SIGTERM, BACKEND_TYPE_BGWORKER);
    2792             : 
    2793             :                 /*
    2794             :                  * Only startup, bgwriter, walreceiver, possibly bgworkers,
    2795             :                  * and/or checkpointer should be active in this state; we just
    2796             :                  * signaled the first four, and we don't want to kill
    2797             :                  * checkpointer yet.
    2798             :                  */
    2799           0 :                 pmState = PM_WAIT_BACKENDS;
    2800             :             }
    2801         390 :             else if (pmState == PM_RUN ||
    2802          44 :                      pmState == PM_WAIT_BACKUP ||
    2803          44 :                      pmState == PM_WAIT_READONLY ||
    2804          44 :                      pmState == PM_WAIT_BACKENDS ||
    2805          22 :                      pmState == PM_HOT_STANDBY)
    2806             :             {
    2807         368 :                 ereport(LOG,
    2808             :                         (errmsg("aborting any active transactions")));
    2809             :                 /* shut down all backends and workers */
    2810         368 :                 SignalSomeChildren(SIGTERM,
    2811             :                                    BACKEND_TYPE_NORMAL | BACKEND_TYPE_AUTOVAC |
    2812             :                                    BACKEND_TYPE_BGWORKER);
    2813             :                 /* and the autovac launcher too */
    2814         368 :                 if (AutoVacPID != 0)
    2815         342 :                     signal_child(AutoVacPID, SIGTERM);
    2816             :                 /* and the walwriter too */
    2817         368 :                 if (WalWriterPID != 0)
    2818         346 :                     signal_child(WalWriterPID, SIGTERM);
    2819         368 :                 pmState = PM_WAIT_BACKENDS;
    2820             :             }
    2821             : 
    2822             :             /*
    2823             :              * Now wait for backends to exit.  If there are none,
    2824             :              * PostmasterStateMachine will take the next step.
    2825             :              */
    2826         368 :             PostmasterStateMachine();
    2827         368 :             break;
    2828             : 
    2829             :         case SIGQUIT:
    2830             : 
    2831             :             /*
    2832             :              * Immediate Shutdown:
    2833             :              *
    2834             :              * abort all children with SIGQUIT, wait for them to exit,
    2835             :              * terminate remaining ones with SIGKILL, then exit without
    2836             :              * attempt to properly shut down the data base system.
    2837             :              */
    2838         192 :             if (Shutdown >= ImmediateShutdown)
    2839           0 :                 break;
    2840         192 :             Shutdown = ImmediateShutdown;
    2841         192 :             ereport(LOG,
    2842             :                     (errmsg("received immediate shutdown request")));
    2843             : 
    2844             :             /* Report status */
    2845         192 :             AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STOPPING);
    2846             : #ifdef USE_SYSTEMD
    2847             :             sd_notify(0, "STOPPING=1");
    2848             : #endif
    2849             : 
    2850         192 :             TerminateChildren(SIGQUIT);
    2851         192 :             pmState = PM_WAIT_BACKENDS;
    2852             : 
    2853             :             /* set stopwatch for them to die */
    2854         192 :             AbortStartTime = time(NULL);
    2855             : 
    2856             :             /*
    2857             :              * Now wait for backends to exit.  If there are none,
    2858             :              * PostmasterStateMachine will take the next step.
    2859             :              */
    2860         192 :             PostmasterStateMachine();
    2861         192 :             break;
    2862             :     }
    2863             : 
    2864         568 :     PG_SETMASK(&UnBlockSig);
    2865             : 
    2866         568 :     errno = save_errno;
    2867         568 : }
    2868             : 
    2869             : /*
    2870             :  * Reaper -- signal handler to cleanup after a child process dies.
    2871             :  */
    2872             : static void
    2873       11464 : reaper(SIGNAL_ARGS)
    2874             : {
    2875       11464 :     int         save_errno = errno;
    2876             :     int         pid;            /* process id of dead child process */
    2877             :     int         exitstatus;     /* its exit status */
    2878             : 
    2879       11464 :     PG_SETMASK(&BlockSig);
    2880             : 
    2881       11464 :     ereport(DEBUG4,
    2882             :             (errmsg_internal("reaping dead processes")));
    2883             : 
    2884       35602 :     while ((pid = waitpid(-1, &exitstatus, WNOHANG)) > 0)
    2885             :     {
    2886             :         /*
    2887             :          * Check if this child was a startup process.
    2888             :          */
    2889       12676 :         if (pid == StartupPID)
    2890             :         {
    2891         576 :             StartupPID = 0;
    2892             : 
    2893             :             /*
    2894             :              * Startup process exited in response to a shutdown request (or it
    2895             :              * completed normally regardless of the shutdown request).
    2896             :              */
    2897         654 :             if (Shutdown > NoShutdown &&
    2898         156 :                 (EXIT_STATUS_0(exitstatus) || EXIT_STATUS_1(exitstatus)))
    2899             :             {
    2900          22 :                 StartupStatus = STARTUP_NOT_RUNNING;
    2901          22 :                 pmState = PM_WAIT_BACKENDS;
    2902             :                 /* PostmasterStateMachine logic does the rest */
    2903          22 :                 continue;
    2904             :             }
    2905             : 
    2906         554 :             if (EXIT_STATUS_3(exitstatus))
    2907             :             {
    2908           0 :                 ereport(LOG,
    2909             :                         (errmsg("shutdown at recovery target")));
    2910           0 :                 StartupStatus = STARTUP_NOT_RUNNING;
    2911           0 :                 Shutdown = SmartShutdown;
    2912           0 :                 TerminateChildren(SIGTERM);
    2913           0 :                 pmState = PM_WAIT_BACKENDS;
    2914             :                 /* PostmasterStateMachine logic does the rest */
    2915           0 :                 continue;
    2916             :             }
    2917             : 
    2918             :             /*
    2919             :              * Unexpected exit of startup process (including FATAL exit)
    2920             :              * during PM_STARTUP is treated as catastrophic. There are no
    2921             :              * other processes running yet, so we can just exit.
    2922             :              */
    2923         554 :             if (pmState == PM_STARTUP && !EXIT_STATUS_0(exitstatus))
    2924             :             {
    2925           0 :                 LogChildExit(LOG, _("startup process"),
    2926             :                              pid, exitstatus);
    2927           0 :                 ereport(LOG,
    2928             :                         (errmsg("aborting startup due to startup process failure")));
    2929           0 :                 ExitPostmaster(1);
    2930             :             }
    2931             : 
    2932             :             /*
    2933             :              * After PM_STARTUP, any unexpected exit (including FATAL exit) of
    2934             :              * the startup process is catastrophic, so kill other children,
    2935             :              * and set StartupStatus so we don't try to reinitialize after
    2936             :              * they're gone.  Exception: if StartupStatus is STARTUP_SIGNALED,
    2937             :              * then we previously sent the startup process a SIGQUIT; so
    2938             :              * that's probably the reason it died, and we do want to try to
    2939             :              * restart in that case.
    2940             :              */
    2941         554 :             if (!EXIT_STATUS_0(exitstatus))
    2942             :             {
    2943          56 :                 if (StartupStatus == STARTUP_SIGNALED)
    2944          56 :                     StartupStatus = STARTUP_NOT_RUNNING;
    2945             :                 else
    2946           0 :                     StartupStatus = STARTUP_CRASHED;
    2947          56 :                 HandleChildCrash(pid, exitstatus,
    2948          56 :                                  _("startup process"));
    2949          56 :                 continue;
    2950             :             }
    2951             : 
    2952             :             /*
    2953             :              * Startup succeeded, commence normal operations
    2954             :              */
    2955         498 :             StartupStatus = STARTUP_NOT_RUNNING;
    2956         498 :             FatalError = false;
    2957             :             Assert(AbortStartTime == 0);
    2958         498 :             ReachedNormalRunning = true;
    2959         498 :             pmState = PM_RUN;
    2960             : 
    2961             :             /*
    2962             :              * Crank up the background tasks, if we didn't do that already
    2963             :              * when we entered consistent recovery state.  It doesn't matter
    2964             :              * if this fails, we'll just try again later.
    2965             :              */
    2966         498 :             if (CheckpointerPID == 0)
    2967         456 :                 CheckpointerPID = StartCheckpointer();
    2968         498 :             if (BgWriterPID == 0)
    2969         456 :                 BgWriterPID = StartBackgroundWriter();
    2970         498 :             if (WalWriterPID == 0)
    2971         498 :                 WalWriterPID = StartWalWriter();
    2972             : 
    2973             :             /*
    2974             :              * Likewise, start other special children as needed.  In a restart
    2975             :              * situation, some of them may be alive already.
    2976             :              */
    2977         498 :             if (!IsBinaryUpgrade && AutoVacuumingActive() && AutoVacPID == 0)
    2978         480 :                 AutoVacPID = StartAutoVacLauncher();
    2979         498 :             if (PgArchStartupAllowed() && PgArchPID == 0)
    2980          10 :                 PgArchPID = pgarch_start();
    2981         498 :             if (PgStatPID == 0)
    2982         456 :                 PgStatPID = pgstat_start();
    2983             : 
    2984             :             /* workers may be scheduled to start now */
    2985         498 :             maybe_start_bgworkers();
    2986             : 
    2987             :             /* at this point we are really open for business */
    2988         496 :             ereport(LOG,
    2989             :                     (errmsg("database system is ready to accept connections")));
    2990             : 
    2991             :             /* Report status */
    2992         496 :             AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_READY);
    2993             : #ifdef USE_SYSTEMD
    2994             :             sd_notify(0, "READY=1");
    2995             : #endif
    2996             : 
    2997         496 :             continue;
    2998             :         }
    2999             : 
    3000             :         /*
    3001             :          * Was it the bgwriter?  Normal exit can be ignored; we'll start a new
    3002             :          * one at the next iteration of the postmaster's main loop, if
    3003             :          * necessary.  Any other exit condition is treated as a crash.
    3004             :          */
    3005       12100 :         if (pid == BgWriterPID)
    3006             :         {
    3007         572 :             BgWriterPID = 0;
    3008         572 :             if (!EXIT_STATUS_0(exitstatus))
    3009         196 :                 HandleChildCrash(pid, exitstatus,
    3010         196 :                                  _("background writer process"));
    3011         572 :             continue;
    3012             :         }
    3013             : 
    3014             :         /*
    3015             :          * Was it the checkpointer?
    3016             :          */
    3017       11528 :         if (pid == CheckpointerPID)
    3018             :         {
    3019         572 :             CheckpointerPID = 0;
    3020         572 :             if (EXIT_STATUS_0(exitstatus) && pmState == PM_SHUTDOWN)
    3021             :             {
    3022             :                 /*
    3023             :                  * OK, we saw normal exit of the checkpointer after it's been
    3024             :                  * told to shut down.  We expect that it wrote a shutdown
    3025             :                  * checkpoint.  (If for some reason it didn't, recovery will
    3026             :                  * occur on next postmaster start.)
    3027             :                  *
    3028             :                  * At this point we should have no normal backend children
    3029             :                  * left (else we'd not be in PM_SHUTDOWN state) but we might
    3030             :                  * have dead_end children to wait for.
    3031             :                  *
    3032             :                  * If we have an archiver subprocess, tell it to do a last
    3033             :                  * archive cycle and quit. Likewise, if we have walsender
    3034             :                  * processes, tell them to send any remaining WAL and quit.
    3035             :                  */
    3036             :                 Assert(Shutdown > NoShutdown);
    3037             : 
    3038             :                 /* Waken archiver for the last time */
    3039         376 :                 if (PgArchPID != 0)
    3040           0 :                     signal_child(PgArchPID, SIGUSR2);
    3041             : 
    3042             :                 /*
    3043             :                  * Waken walsenders for the last time. No regular backends
    3044             :                  * should be around anymore.
    3045             :                  */
    3046         376 :                 SignalChildren(SIGUSR2);
    3047             : 
    3048         376 :                 pmState = PM_SHUTDOWN_2;
    3049             : 
    3050             :                 /*
    3051             :                  * We can also shut down the stats collector now; there's
    3052             :                  * nothing left for it to do.
    3053             :                  */
    3054         752 :                 if (PgStatPID != 0)
    3055         376 :                     signal_child(PgStatPID, SIGQUIT);
    3056             :             }
    3057             :             else
    3058             :             {
    3059             :                 /*
    3060             :                  * Any unexpected exit of the checkpointer (including FATAL
    3061             :                  * exit) is treated as a crash.
    3062             :                  */
    3063         196 :                 HandleChildCrash(pid, exitstatus,
    3064         196 :                                  _("checkpointer process"));
    3065             :             }
    3066             : 
    3067         572 :             continue;
    3068             :         }
    3069             : 
    3070             :         /*
    3071             :          * Was it the wal writer?  Normal exit can be ignored; we'll start a
    3072             :          * new one at the next iteration of the postmaster's main loop, if
    3073             :          * necessary.  Any other exit condition is treated as a crash.
    3074             :          */
    3075       10956 :         if (pid == WalWriterPID)
    3076             :         {
    3077         494 :             WalWriterPID = 0;
    3078         494 :             if (!EXIT_STATUS_0(exitstatus))
    3079         140 :                 HandleChildCrash(pid, exitstatus,
    3080         140 :                                  _("WAL writer process"));
    3081         494 :             continue;
    3082             :         }
    3083             : 
    3084             :         /*
    3085             :          * Was it the wal receiver?  If exit status is zero (normal) or one
    3086             :          * (FATAL exit), we assume everything is all right just like normal
    3087             :          * backends.  (If we need a new wal receiver, we'll start one at the
    3088             :          * next iteration of the postmaster's main loop.)
    3089             :          */
    3090       10462 :         if (pid == WalReceiverPID)
    3091             :         {
    3092         204 :             WalReceiverPID = 0;
    3093         204 :             if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
    3094          20 :                 HandleChildCrash(pid, exitstatus,
    3095          20 :                                  _("WAL receiver process"));
    3096         204 :             continue;
    3097             :         }
    3098             : 
    3099             :         /*
    3100             :          * Was it the autovacuum launcher?  Normal exit can be ignored; we'll
    3101             :          * start a new one at the next iteration of the postmaster's main
    3102             :          * loop, if necessary.  Any other exit condition is treated as a
    3103             :          * crash.
    3104             :          */
    3105       10258 :         if (pid == AutoVacPID)
    3106             :         {
    3107         476 :             AutoVacPID = 0;
    3108         476 :             if (!EXIT_STATUS_0(exitstatus))
    3109         134 :                 HandleChildCrash(pid, exitstatus,
    3110         134 :                                  _("autovacuum launcher process"));
    3111         476 :             continue;
    3112             :         }
    3113             : 
    3114             :         /*
    3115             :          * Was it the archiver?  If so, just try to start a new one; no need
    3116             :          * to force reset of the rest of the system.  (If fail, we'll try
    3117             :          * again in future cycles of the main loop.).  Unless we were waiting
    3118             :          * for it to shut down; don't restart it in that case, and
    3119             :          * PostmasterStateMachine() will advance to the next shutdown step.
    3120             :          */
    3121        9782 :         if (pid == PgArchPID)
    3122             :         {
    3123          10 :             PgArchPID = 0;
    3124          10 :             if (!EXIT_STATUS_0(exitstatus))
    3125          10 :                 LogChildExit(LOG, _("archiver process"),
    3126             :                              pid, exitstatus);
    3127          10 :             if (PgArchStartupAllowed())
    3128           0 :                 PgArchPID = pgarch_start();
    3129          10 :             continue;
    3130             :         }
    3131             : 
    3132             :         /*
    3133             :          * Was it the statistics collector?  If so, just try to start a new
    3134             :          * one; no need to force reset of the rest of the system.  (If fail,
    3135             :          * we'll try again in future cycles of the main loop.)
    3136             :          */
    3137        9772 :         if (pid == PgStatPID)
    3138             :         {
    3139         572 :             PgStatPID = 0;
    3140         572 :             if (!EXIT_STATUS_0(exitstatus))
    3141           0 :                 LogChildExit(LOG, _("statistics collector process"),
    3142             :                              pid, exitstatus);
    3143         572 :             if (pmState == PM_RUN || pmState == PM_HOT_STANDBY)
    3144           0 :                 PgStatPID = pgstat_start();
    3145         572 :             continue;
    3146             :         }
    3147             : 
    3148             :         /* Was it the system logger?  If so, try to start a new one */
    3149        9200 :         if (pid == SysLoggerPID)
    3150             :         {
    3151           0 :             SysLoggerPID = 0;
    3152             :             /* for safety's sake, launch new logger *first* */
    3153           0 :             SysLoggerPID = SysLogger_Start();
    3154           0 :             if (!EXIT_STATUS_0(exitstatus))
    3155           0 :                 LogChildExit(LOG, _("system logger process"),
    3156             :                              pid, exitstatus);
    3157           0 :             continue;
    3158             :         }
    3159             : 
    3160             :         /* Was it one of our background workers? */
    3161        9200 :         if (CleanupBackgroundWorker(pid, exitstatus))
    3162             :         {
    3163             :             /* have it be restarted */
    3164        2276 :             HaveCrashedWorker = true;
    3165        2276 :             continue;
    3166             :         }
    3167             : 
    3168             :         /*
    3169             :          * Else do standard backend child cleanup.
    3170             :          */
    3171        6924 :         CleanupBackend(pid, exitstatus);
    3172             :     }                           /* loop over pending child-death reports */
    3173             : 
    3174             :     /*
    3175             :      * After cleaning out the SIGCHLD queue, see if we have any state changes
    3176             :      * or actions to make.
    3177             :      */
    3178       11462 :     PostmasterStateMachine();
    3179             : 
    3180             :     /* Done with signal handler */
    3181       10894 :     PG_SETMASK(&UnBlockSig);
    3182             : 
    3183       10894 :     errno = save_errno;
    3184       10894 : }
    3185             : 
    3186             : /*
    3187             :  * Scan the bgworkers list and see if the given PID (which has just stopped
    3188             :  * or crashed) is in it.  Handle its shutdown if so, and return true.  If not a
    3189             :  * bgworker, return false.
    3190             :  *
    3191             :  * This is heavily based on CleanupBackend.  One important difference is that
    3192             :  * we don't know yet that the dying process is a bgworker, so we must be silent
    3193             :  * until we're sure it is.
    3194             :  */
    3195             : static bool
    3196        9200 : CleanupBackgroundWorker(int pid,
    3197             :                         int exitstatus) /* child's exit status */
    3198             : {
    3199             :     char        namebuf[MAXPGPATH];
    3200             :     slist_mutable_iter iter;
    3201             : 
    3202       18520 :     slist_foreach_modify(iter, &BackgroundWorkerList)
    3203             :     {
    3204             :         RegisteredBgWorker *rw;
    3205             : 
    3206       10398 :         rw = slist_container(RegisteredBgWorker, rw_lnode, iter.cur);
    3207             : 
    3208       10398 :         if (rw->rw_pid != pid)
    3209        8122 :             continue;
    3210             : 
    3211             : #ifdef WIN32
    3212             :         /* see CleanupBackend */
    3213             :         if (exitstatus == ERROR_WAIT_NO_CHILDREN)
    3214             :             exitstatus = 0;
    3215             : #endif
    3216             : 
    3217        2276 :         snprintf(namebuf, MAXPGPATH, _("background worker \"%s\""),
    3218        2276 :                  rw->rw_worker.bgw_type);
    3219             : 
    3220             : 
    3221        2276 :         if (!EXIT_STATUS_0(exitstatus))
    3222             :         {
    3223             :             /* Record timestamp, so we know when to restart the worker. */
    3224         562 :             rw->rw_crashed_at = GetCurrentTimestamp();
    3225             :         }
    3226             :         else
    3227             :         {
    3228             :             /* Zero exit status means terminate */
    3229        1714 :             rw->rw_crashed_at = 0;
    3230        1714 :             rw->rw_terminate = true;
    3231             :         }
    3232             : 
    3233             :         /*
    3234             :          * Additionally, for shared-memory-connected workers, just like a
    3235             :          * backend, any exit status other than 0 or 1 is considered a crash
    3236             :          * and causes a system-wide restart.
    3237             :          */
    3238        2276 :         if ((rw->rw_worker.bgw_flags & BGWORKER_SHMEM_ACCESS) != 0)
    3239             :         {
    3240        2276 :             if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
    3241             :             {
    3242         140 :                 HandleChildCrash(pid, exitstatus, namebuf);
    3243         140 :                 return true;
    3244             :             }
    3245             :         }
    3246             : 
    3247             :         /*
    3248             :          * We must release the postmaster child slot whether this worker is
    3249             :          * connected to shared memory or not, but we only treat it as a crash
    3250             :          * if it is in fact connected.
    3251             :          */
    3252        2136 :         if (!ReleasePostmasterChildSlot(rw->rw_child_slot) &&
    3253           0 :             (rw->rw_worker.bgw_flags & BGWORKER_SHMEM_ACCESS) != 0)
    3254             :         {
    3255           0 :             HandleChildCrash(pid, exitstatus, namebuf);
    3256           0 :             return true;
    3257             :         }
    3258             : 
    3259             :         /* Get it out of the BackendList and clear out remaining data */
    3260        2136 :         dlist_delete(&rw->rw_backend->elem);
    3261             : #ifdef EXEC_BACKEND
    3262             :         ShmemBackendArrayRemove(rw->rw_backend);
    3263             : #endif
    3264             : 
    3265             :         /*
    3266             :          * It's possible that this background worker started some OTHER
    3267             :          * background worker and asked to be notified when that worker started
    3268             :          * or stopped.  If so, cancel any notifications destined for the
    3269             :          * now-dead backend.
    3270             :          */
    3271        2136 :         if (rw->rw_backend->bgworker_notify)
    3272          48 :             BackgroundWorkerStopNotifications(rw->rw_pid);
    3273        2136 :         free(rw->rw_backend);
    3274        2136 :         rw->rw_backend = NULL;
    3275        2136 :         rw->rw_pid = 0;
    3276        2136 :         rw->rw_child_slot = 0;
    3277        2136 :         ReportBackgroundWorkerExit(&iter);  /* report child death */
    3278             : 
    3279        2136 :         LogChildExit(EXIT_STATUS_0(exitstatus) ? DEBUG1 : LOG,
    3280             :                      namebuf, pid, exitstatus);
    3281             : 
    3282        2136 :         return true;
    3283             :     }
    3284             : 
    3285        6924 :     return false;
    3286             : }
    3287             : 
    3288             : /*
    3289             :  * CleanupBackend -- cleanup after terminated backend.
    3290             :  *
    3291             :  * Remove all local state associated with backend.
    3292             :  *
    3293             :  * If you change this, see also CleanupBackgroundWorker.
    3294             :  */
    3295             : static void
    3296        6924 : CleanupBackend(int pid,
    3297             :                int exitstatus)  /* child's exit status. */
    3298             : {
    3299             :     dlist_mutable_iter iter;
    3300             : 
    3301        6924 :     LogChildExit(DEBUG2, _("server process"), pid, exitstatus);
    3302             : 
    3303             :     /*
    3304             :      * If a backend dies in an ugly way then we must signal all other backends
    3305             :      * to quickdie.  If exit status is zero (normal) or one (FATAL exit), we
    3306             :      * assume everything is all right and proceed to remove the backend from
    3307             :      * the active backend list.
    3308             :      */
    3309             : 
    3310             : #ifdef WIN32
    3311             : 
    3312             :     /*
    3313             :      * On win32, also treat ERROR_WAIT_NO_CHILDREN (128) as nonfatal case,
    3314             :      * since that sometimes happens under load when the process fails to start
    3315             :      * properly (long before it starts using shared memory). Microsoft reports
    3316             :      * it is related to mutex failure:
    3317             :      * http://archives.postgresql.org/pgsql-hackers/2010-09/msg00790.php
    3318             :      */
    3319             :     if (exitstatus == ERROR_WAIT_NO_CHILDREN)
    3320             :     {
    3321             :         LogChildExit(LOG, _("server process"), pid, exitstatus);
    3322             :         exitstatus = 0;
    3323             :     }
    3324             : #endif
    3325             : 
    3326        6924 :     if (!EXIT_STATUS_0(exitstatus) && !EXIT_STATUS_1(exitstatus))
    3327             :     {
    3328         120 :         HandleChildCrash(pid, exitstatus, _("server process"));
    3329         120 :         return;
    3330             :     }
    3331             : 
    3332       15396 :     dlist_foreach_modify(iter, &BackendList)
    3333             :     {
    3334       15396 :         Backend    *bp = dlist_container(Backend, elem, iter.cur);
    3335             : 
    3336       15396 :         if (bp->pid == pid)
    3337             :         {
    3338        6804 :             if (!bp->dead_end)
    3339             :             {
    3340        6724 :                 if (!ReleasePostmasterChildSlot(bp->child_slot))
    3341             :                 {
    3342             :                     /*
    3343             :                      * Uh-oh, the child failed to clean itself up.  Treat as a
    3344             :                      * crash after all.
    3345             :                      */
    3346           0 :                     HandleChildCrash(pid, exitstatus, _("server process"));
    3347           0 :                     return;
    3348             :                 }
    3349             : #ifdef EXEC_BACKEND
    3350             :                 ShmemBackendArrayRemove(bp);
    3351             : #endif
    3352             :             }
    3353        6804 :             if (bp->bgworker_notify)
    3354             :             {
    3355             :                 /*
    3356             :                  * This backend may have been slated to receive SIGUSR1 when
    3357             :                  * some background worker started or stopped.  Cancel those
    3358             :                  * notifications, as we don't want to signal PIDs that are not
    3359             :                  * PostgreSQL backends.  This gets skipped in the (probably
    3360             :                  * very common) case where the backend has never requested any
    3361             :                  * such notifications.
    3362             :                  */
    3363          40 :                 BackgroundWorkerStopNotifications(bp->pid);
    3364             :             }
    3365        6804 :             dlist_delete(iter.cur);
    3366        6804 :             free(bp);
    3367        6804 :             break;
    3368             :         }
    3369             :     }
    3370             : }
    3371             : 
    3372             : /*
    3373             :  * HandleChildCrash -- cleanup after failed backend, bgwriter, checkpointer,
    3374             :  * walwriter, autovacuum, or background worker.
    3375             :  *
    3376             :  * The objectives here are to clean up our local state about the child
    3377             :  * process, and to signal all other remaining children to quickdie.
    3378             :  */
    3379             : static void
    3380        1002 : HandleChildCrash(int pid, int exitstatus, const char *procname)
    3381             : {
    3382             :     dlist_mutable_iter iter;
    3383             :     slist_iter  siter;
    3384             :     Backend    *bp;
    3385             :     bool        take_action;
    3386             : 
    3387             :     /*
    3388             :      * We only log messages and send signals if this is the first process
    3389             :      * crash and we're not doing an immediate shutdown; otherwise, we're only
    3390             :      * here to update postmaster's idea of live processes.  If we have already
    3391             :      * signalled children, nonzero exit status is to be expected, so don't
    3392             :      * clutter log.
    3393             :      */
    3394        1002 :     take_action = !FatalError && Shutdown != ImmediateShutdown;
    3395             : 
    3396        1002 :     if (take_action)
    3397             :     {
    3398           4 :         LogChildExit(LOG, procname, pid, exitstatus);
    3399           4 :         ereport(LOG,
    3400             :                 (errmsg("terminating any other active server processes")));
    3401             :     }
    3402             : 
    3403             :     /* Process background workers. */
    3404        2004 :     slist_foreach(siter, &BackgroundWorkerList)
    3405             :     {
    3406             :         RegisteredBgWorker *rw;
    3407             : 
    3408        1002 :         rw = slist_container(RegisteredBgWorker, rw_lnode, siter.cur);
    3409        1002 :         if (rw->rw_pid == 0)
    3410         452 :             continue;           /* not running */
    3411         550 :         if (rw->rw_pid == pid)
    3412             :         {
    3413             :             /*
    3414             :              * Found entry for freshly-dead worker, so remove it.
    3415             :              */
    3416         140 :             (void) ReleasePostmasterChildSlot(rw->rw_child_slot);
    3417         140 :             dlist_delete(&rw->rw_backend->elem);
    3418             : #ifdef EXEC_BACKEND
    3419             :             ShmemBackendArrayRemove(rw->rw_backend);
    3420             : #endif
    3421         140 :             free(rw->rw_backend);
    3422         140 :             rw->rw_backend = NULL;
    3423         140 :             rw->rw_pid = 0;
    3424         140 :             rw->rw_child_slot = 0;
    3425             :             /* don't reset crashed_at */
    3426             :             /* don't report child stop, either */
    3427             :             /* Keep looping so we can signal remaining workers */
    3428             :         }
    3429             :         else
    3430             :         {
    3431             :             /*
    3432             :              * This worker is still alive.  Unless we did so already, tell it
    3433             :              * to commit hara-kiri.
    3434             :              *
    3435             :              * SIGQUIT is the special signal that says exit without proc_exit
    3436             :              * and let the user know what's going on. But if SendStop is set
    3437             :              * (-s on command line), then we send SIGSTOP instead, so that we
    3438             :              * can get core dumps from all backends by hand.
    3439             :              */
    3440         410 :             if (take_action)
    3441             :             {
    3442           4 :                 ereport(DEBUG2,
    3443             :                         (errmsg_internal("sending %s to process %d",
    3444             :                                          (SendStop ? "SIGSTOP" : "SIGQUIT"),
    3445             :                                          (int) rw->rw_pid)));
    3446           4 :                 signal_child(rw->rw_pid, (SendStop ? SIGSTOP : SIGQUIT));
    3447             :             }
    3448             :         }
    3449             :     }
    3450             : 
    3451             :     /* Process regular backends */
    3452        2070 :     dlist_foreach_modify(iter, &BackendList)
    3453             :     {
    3454        1068 :         bp = dlist_container(Backend, elem, iter.cur);
    3455             : 
    3456        1068 :         if (bp->pid == pid)
    3457             :         {
    3458             :             /*
    3459             :              * Found entry for freshly-dead backend, so remove it.
    3460             :              */
    3461         120 :             if (!bp->dead_end)
    3462             :             {
    3463         120 :                 (void) ReleasePostmasterChildSlot(bp->child_slot);
    3464             : #ifdef EXEC_BACKEND
    3465             :                 ShmemBackendArrayRemove(bp);
    3466             : #endif
    3467             :             }
    3468         120 :             dlist_delete(iter.cur);
    3469         120 :             free(bp);
    3470             :             /* Keep looping so we can signal remaining backends */
    3471             :         }
    3472             :         else
    3473             :         {
    3474             :             /*
    3475             :              * This backend is still alive.  Unless we did so already, tell it
    3476             :              * to commit hara-kiri.
    3477             :              *
    3478             :              * SIGQUIT is the special signal that says exit without proc_exit
    3479             :              * and let the user know what's going on. But if SendStop is set
    3480             :              * (-s on command line), then we send SIGSTOP instead, so that we
    3481             :              * can get core dumps from all backends by hand.
    3482             :              *
    3483             :              * We could exclude dead_end children here, but at least in the
    3484             :              * SIGSTOP case it seems better to include them.
    3485             :              *
    3486             :              * Background workers were already processed above; ignore them
    3487             :              * here.
    3488             :              */
    3489         948 :             if (bp->bkend_type == BACKEND_TYPE_BGWORKER)
    3490         410 :                 continue;
    3491             : 
    3492         538 :             if (take_action)
    3493             :             {
    3494           4 :                 ereport(DEBUG2,
    3495             :                         (errmsg_internal("sending %s to process %d",
    3496             :                                          (SendStop ? "SIGSTOP" : "SIGQUIT"),
    3497             :                                          (int) bp->pid)));
    3498           4 :                 signal_child(bp->pid, (SendStop ? SIGSTOP : SIGQUIT));
    3499             :             }
    3500             :         }
    3501             :     }
    3502             : 
    3503             :     /* Take care of the startup process too */
    3504        1002 :     if (pid == StartupPID)
    3505             :     {
    3506           0 :         StartupPID = 0;
    3507           0 :         StartupStatus = STARTUP_CRASHED;
    3508             :     }
    3509        1002 :     else if (StartupPID != 0 && take_action)
    3510             :     {
    3511           0 :         ereport(DEBUG2,
    3512             :                 (errmsg_internal("sending %s to process %d",
    3513             :                                  (SendStop ? "SIGSTOP" : "SIGQUIT"),
    3514             :                                  (int) StartupPID)));
    3515           0 :         signal_child(StartupPID, (SendStop ? SIGSTOP : SIGQUIT));
    3516           0 :         StartupStatus = STARTUP_SIGNALED;
    3517             :     }
    3518             : 
    3519             :     /* Take care of the bgwriter too */
    3520        1002 :     if (pid == BgWriterPID)
    3521           0 :         BgWriterPID = 0;
    3522        1002 :     else if (BgWriterPID != 0 && take_action)
    3523             :     {
    3524           4 :         ereport(DEBUG2,
    3525             :                 (errmsg_internal("sending %s to process %d",
    3526             :                                  (SendStop ? "SIGSTOP" : "SIGQUIT"),
    3527             :                                  (int) BgWriterPID)));
    3528           4 :         signal_child(BgWriterPID, (SendStop ? SIGSTOP : SIGQUIT));
    3529             :     }
    3530             : 
    3531             :     /* Take care of the checkpointer too */
    3532        1002 :     if (pid == CheckpointerPID)
    3533           0 :         CheckpointerPID = 0;
    3534        1002 :     else if (CheckpointerPID != 0 && take_action)
    3535             :     {
    3536           4 :         ereport(DEBUG2,
    3537             :                 (errmsg_internal("sending %s to process %d",
    3538             :                                  (SendStop ? "SIGSTOP" : "SIGQUIT"),
    3539             :                                  (int) CheckpointerPID)));
    3540           4 :         signal_child(CheckpointerPID, (SendStop ? SIGSTOP : SIGQUIT));
    3541             :     }
    3542             : 
    3543             :     /* Take care of the walwriter too */
    3544        1002 :     if (pid == WalWriterPID)
    3545           0 :         WalWriterPID = 0;
    3546        1002 :     else if (WalWriterPID != 0 && take_action)
    3547             :     {
    3548           4 :         ereport(DEBUG2,
    3549             :                 (errmsg_internal("sending %s to process %d",
    3550             :                                  (SendStop ? "SIGSTOP" : "SIGQUIT"),
    3551             :                                  (int) WalWriterPID)));
    3552           4 :         signal_child(WalWriterPID, (SendStop ? SIGSTOP : SIGQUIT));
    3553             :     }
    3554             : 
    3555             :     /* Take care of the walreceiver too */
    3556        1002 :     if (pid == WalReceiverPID)
    3557           0 :         WalReceiverPID = 0;
    3558        1002 :     else if (WalReceiverPID != 0 && take_action)
    3559             :     {
    3560           0 :         ereport(DEBUG2,
    3561             :                 (errmsg_internal("sending %s to process %d",
    3562             :                                  (SendStop ? "SIGSTOP" : "SIGQUIT"),
    3563             :                                  (int) WalReceiverPID)));
    3564           0 :         signal_child(WalReceiverPID, (SendStop ? SIGSTOP : SIGQUIT));
    3565             :     }
    3566             : 
    3567             :     /* Take care of the autovacuum launcher too */
    3568        1002 :     if (pid == AutoVacPID)
    3569           0 :         AutoVacPID = 0;
    3570        1002 :     else if (AutoVacPID != 0 && take_action)
    3571             :     {
    3572           4 :         ereport(DEBUG2,
    3573             :                 (errmsg_internal("sending %s to process %d",
    3574             :                                  (SendStop ? "SIGSTOP" : "SIGQUIT"),
    3575             :                                  (int) AutoVacPID)));
    3576           4 :         signal_child(AutoVacPID, (SendStop ? SIGSTOP : SIGQUIT));
    3577             :     }
    3578             : 
    3579             :     /*
    3580             :      * Force a power-cycle of the pgarch process too.  (This isn't absolutely
    3581             :      * necessary, but it seems like a good idea for robustness, and it
    3582             :      * simplifies the state-machine logic in the case where a shutdown request
    3583             :      * arrives during crash processing.)
    3584             :      */
    3585        1002 :     if (PgArchPID != 0 && take_action)
    3586             :     {
    3587           0 :         ereport(DEBUG2,
    3588             :                 (errmsg_internal("sending %s to process %d",
    3589             :                                  "SIGQUIT",
    3590             :                                  (int) PgArchPID)));
    3591           0 :         signal_child(PgArchPID, SIGQUIT);
    3592             :     }
    3593             : 
    3594             :     /*
    3595             :      * Force a power-cycle of the pgstat process too.  (This isn't absolutely
    3596             :      * necessary, but it seems like a good idea for robustness, and it
    3597             :      * simplifies the state-machine logic in the case where a shutdown request
    3598             :      * arrives during crash processing.)
    3599             :      */
    3600        1002 :     if (PgStatPID != 0 && take_action)
    3601             :     {
    3602           4 :         ereport(DEBUG2,
    3603             :                 (errmsg_internal("sending %s to process %d",
    3604             :                                  "SIGQUIT",
    3605             :                                  (int) PgStatPID)));
    3606           4 :         signal_child(PgStatPID, SIGQUIT);
    3607           4 :         allow_immediate_pgstat_restart();
    3608             :     }
    3609             : 
    3610             :     /* We do NOT restart the syslogger */
    3611             : 
    3612        1002 :     if (Shutdown != ImmediateShutdown)
    3613          28 :         FatalError = true;
    3614             : 
    3615             :     /* We now transit into a state of waiting for children to die */
    3616        2004 :     if (pmState == PM_RECOVERY ||
    3617        2004 :         pmState == PM_HOT_STANDBY ||
    3618        2000 :         pmState == PM_RUN ||
    3619        1996 :         pmState == PM_WAIT_BACKUP ||
    3620        1996 :         pmState == PM_WAIT_READONLY ||
    3621         998 :         pmState == PM_SHUTDOWN)
    3622           4 :         pmState = PM_WAIT_BACKENDS;
    3623             : 
    3624             :     /*
    3625             :      * .. and if this doesn't happen quickly enough, now the clock is ticking
    3626             :      * for us to kill them without mercy.
    3627             :      */
    3628        1002 :     if (AbortStartTime == 0)
    3629           4 :         AbortStartTime = time(NULL);
    3630        1002 : }
    3631             : 
    3632             : /*
    3633             :  * Log the death of a child process.
    3634             :  */
    3635             : static void
    3636        9074 : LogChildExit(int lev, const char *procname, int pid, int exitstatus)
    3637             : {
    3638             :     /*
    3639             :      * size of activity_buffer is arbitrary, but set equal to default
    3640             :      * track_activity_query_size
    3641             :      */
    3642             :     char        activity_buffer[1024];
    3643        9074 :     const char *activity = NULL;
    3644             : 
    3645        9074 :     if (!EXIT_STATUS_0(exitstatus))
    3646         722 :         activity = pgstat_get_crashed_backend_activity(pid,
    3647             :                                                        activity_buffer,
    3648             :                                                        sizeof(activity_buffer));
    3649             : 
    3650        9074 :     if (WIFEXITED(exitstatus))
    3651        9070 :         ereport(lev,
    3652             : 
    3653             :         /*------
    3654             :           translator: %s is a noun phrase describing a child process, such as
    3655             :           "server process" */
    3656             :                 (errmsg("%s (PID %d) exited with exit code %d",
    3657             :                         procname, pid, WEXITSTATUS(exitstatus)),
    3658             :                  activity ? errdetail("Failed process was running: %s", activity) : 0));
    3659           4 :     else if (WIFSIGNALED(exitstatus))
    3660             :     {
    3661             : #if defined(WIN32)
    3662             :         ereport(lev,
    3663             : 
    3664             :         /*------
    3665             :           translator: %s is a noun phrase describing a child process, such as
    3666             :           "server process" */
    3667             :                 (errmsg("%s (PID %d) was terminated by exception 0x%X",
    3668             :                         procname, pid, WTERMSIG(exitstatus)),
    3669             :                  errhint("See C include file \"ntstatus.h\" for a description of the hexadecimal value."),
    3670             :                  activity ? errdetail("Failed process was running: %s", activity) : 0));
    3671             : #else
    3672           4 :         ereport(lev,
    3673             : 
    3674             :         /*------
    3675             :           translator: %s is a noun phrase describing a child process, such as
    3676             :           "server process" */
    3677             :                 (errmsg("%s (PID %d) was terminated by signal %d: %s",
    3678             :                         procname, pid, WTERMSIG(exitstatus),
    3679             :                         pg_strsignal(WTERMSIG(exitstatus))),
    3680             :                  activity ? errdetail("Failed process was running: %s", activity) : 0));
    3681             : #endif
    3682             :     }
    3683             :     else
    3684           0 :         ereport(lev,
    3685             : 
    3686             :         /*------
    3687             :           translator: %s is a noun phrase describing a child process, such as
    3688             :           "server process" */
    3689             :                 (errmsg("%s (PID %d) exited with unrecognized status %d",
    3690             :                         procname, pid, exitstatus),
    3691             :                  activity ? errdetail("Failed process was running: %s", activity) : 0));
    3692        9074 : }
    3693             : 
    3694             : /*
    3695             :  * Advance the postmaster's state machine and take actions as appropriate
    3696             :  *
    3697             :  * This is common code for pmdie(), reaper() and sigusr1_handler(), which
    3698             :  * receive the signals that might mean we need to change state.
    3699             :  */
    3700             : static void
    3701       12538 : PostmasterStateMachine(void)
    3702             : {
    3703       12538 :     if (pmState == PM_WAIT_BACKUP)
    3704             :     {
    3705             :         /*
    3706             :          * PM_WAIT_BACKUP state ends when online backup mode is not active.
    3707             :          */
    3708           8 :         if (!BackupInProgress())
    3709           8 :             pmState = PM_WAIT_BACKENDS;
    3710             :     }
    3711             : 
    3712       12538 :     if (pmState == PM_WAIT_READONLY)
    3713             :     {
    3714             :         /*
    3715             :          * PM_WAIT_READONLY state ends when we have no regular backends that
    3716             :          * have been started during recovery.  We kill the startup and
    3717             :          * walreceiver processes and transition to PM_WAIT_BACKENDS.  Ideally,
    3718             :          * we might like to kill these processes first and then wait for
    3719             :          * backends to die off, but that doesn't work at present because
    3720             :          * killing the startup process doesn't release its locks.
    3721             :          */
    3722           0 :         if (CountChildren(BACKEND_TYPE_NORMAL) == 0)
    3723             :         {
    3724           0 :             if (StartupPID != 0)
    3725           0 :                 signal_child(StartupPID, SIGTERM);
    3726           0 :             if (WalReceiverPID != 0)
    3727           0 :                 signal_child(WalReceiverPID, SIGTERM);
    3728           0 :             pmState = PM_WAIT_BACKENDS;
    3729             :         }
    3730             :     }
    3731             : 
    3732             :     /*
    3733             :      * If we are in a state-machine state that implies waiting for backends to
    3734             :      * exit, see if they're all gone, and change state if so.
    3735             :      */
    3736       12538 :     if (pmState == PM_WAIT_BACKENDS)
    3737             :     {
    3738             :         /*
    3739             :          * PM_WAIT_BACKENDS state ends when we have no regular backends
    3740             :          * (including autovac workers), no bgworkers (including unconnected
    3741             :          * ones), and no walwriter, autovac launcher or bgwriter.  If we are
    3742             :          * doing crash recovery or an immediate shutdown then we expect the
    3743             :          * checkpointer to exit as well, otherwise not. The archiver, stats,
    3744             :          * and syslogger processes are disregarded since they are not
    3745             :          * connected to shared memory; we also disregard dead_end children
    3746             :          * here. Walsenders are also disregarded, they will be terminated
    3747             :          * later after writing the checkpoint record, like the archiver
    3748             :          * process.
    3749             :          */
    3750        3970 :         if (CountChildren(BACKEND_TYPE_NORMAL | BACKEND_TYPE_WORKER) == 0 &&
    3751        2348 :             StartupPID == 0 &&
    3752        2236 :             WalReceiverPID == 0 &&
    3753        1992 :             BgWriterPID == 0 &&
    3754        1498 :             (CheckpointerPID == 0 ||
    3755        2074 :              (!FatalError && Shutdown < ImmediateShutdown)) &&
    3756        1536 :             WalWriterPID == 0 &&
    3757         690 :             AutoVacPID == 0)
    3758             :         {
    3759         572 :             if (Shutdown >= ImmediateShutdown || FatalError)
    3760             :             {
    3761             :                 /*
    3762             :                  * Start waiting for dead_end children to die.  This state
    3763             :                  * change causes ServerLoop to stop creating new ones.
    3764             :                  */
    3765         196 :                 pmState = PM_WAIT_DEAD_END;
    3766             : 
    3767             :                 /*
    3768             :                  * We already SIGQUIT'd the archiver and stats processes, if
    3769             :                  * any, when we started immediate shutdown or entered
    3770             :                  * FatalError state.
    3771             :                  */
    3772             :             }
    3773             :             else
    3774             :             {
    3775             :                 /*
    3776             :                  * If we get here, we are proceeding with normal shutdown. All
    3777             :                  * the regular children are gone, and it's time to tell the
    3778             :                  * checkpointer to do a shutdown checkpoint.
    3779             :                  */
    3780             :                 Assert(Shutdown > NoShutdown);
    3781             :                 /* Start the checkpointer if not running */
    3782         376 :                 if (CheckpointerPID == 0)
    3783           0 :                     CheckpointerPID = StartCheckpointer();
    3784             :                 /* And tell it to shut down */
    3785         376 :                 if (CheckpointerPID != 0)
    3786             :                 {
    3787         376 :                     signal_child(CheckpointerPID, SIGUSR2);
    3788         376 :                     pmState = PM_SHUTDOWN;
    3789             :                 }
    3790             :                 else
    3791             :                 {
    3792             :                     /*
    3793             :                      * If we failed to fork a checkpointer, just shut down.
    3794             :                      * Any required cleanup will happen at next restart. We
    3795             :                      * set FatalError so that an "abnormal shutdown" message
    3796             :                      * gets logged when we exit.
    3797             :                      */
    3798           0 :                     FatalError = true;
    3799           0 :                     pmState = PM_WAIT_DEAD_END;
    3800             : 
    3801             :                     /* Kill the walsenders, archiver and stats collector too */
    3802           0 :                     SignalChildren(SIGQUIT);
    3803           0 :                     if (PgArchPID != 0)
    3804           0 :                         signal_child(PgArchPID, SIGQUIT);
    3805           0 :                     if (PgStatPID != 0)
    3806           0 :                         signal_child(PgStatPID, SIGQUIT);
    3807             :                 }
    3808             :             }
    3809             :         }
    3810             :     }
    3811             : 
    3812       12538 :     if (pmState == PM_SHUTDOWN_2)
    3813             :     {
    3814             :         /*
    3815             :          * PM_SHUTDOWN_2 state ends when there's no other children than
    3816             :          * dead_end children left. There shouldn't be any regular backends
    3817             :          * left by now anyway; what we're really waiting for is walsenders and
    3818             :          * archiver.
    3819             :          */
    3820         432 :         if (PgArchPID == 0 && CountChildren(BACKEND_TYPE_ALL) == 0)
    3821             :         {
    3822         376 :             pmState = PM_WAIT_DEAD_END;
    3823             :         }
    3824             :     }
    3825             : 
    3826       12538 :     if (pmState == PM_WAIT_DEAD_END)
    3827             :     {
    3828             :         /*
    3829             :          * PM_WAIT_DEAD_END state ends when the BackendList is entirely empty
    3830             :          * (ie, no dead_end children remain), and the archiver and stats
    3831             :          * collector are gone too.
    3832             :          *
    3833             :          * The reason we wait for those two is to protect them against a new
    3834             :          * postmaster starting conflicting subprocesses; this isn't an
    3835             :          * ironclad protection, but it at least helps in the
    3836             :          * shutdown-and-immediately-restart scenario.  Note that they have
    3837             :          * already been sent appropriate shutdown signals, either during a
    3838             :          * normal state transition leading up to PM_WAIT_DEAD_END, or during
    3839             :          * FatalError processing.
    3840             :          */
    3841        2274 :         if (dlist_is_empty(&BackendList) &&
    3842        2260 :             PgArchPID == 0 && PgStatPID == 0)
    3843             :         {
    3844             :             /* These other guys should be dead already */
    3845             :             Assert(StartupPID == 0);
    3846             :             Assert(WalReceiverPID == 0);
    3847             :             Assert(BgWriterPID == 0);
    3848             :             Assert(CheckpointerPID == 0);
    3849             :             Assert(WalWriterPID == 0);
    3850             :             Assert(AutoVacPID == 0);
    3851             :             /* syslogger is not considered here */
    3852         572 :             pmState = PM_NO_CHILDREN;
    3853             :         }
    3854             :     }
    3855             : 
    3856             :     /*
    3857             :      * If we've been told to shut down, we exit as soon as there are no
    3858             :      * remaining children.  If there was a crash, cleanup will occur at the
    3859             :      * next startup.  (Before PostgreSQL 8.3, we tried to recover from the
    3860             :      * crash before exiting, but that seems unwise if we are quitting because
    3861             :      * we got SIGTERM from init --- there may well not be time for recovery
    3862             :      * before init decides to SIGKILL us.)
    3863             :      *
    3864             :      * Note that the syslogger continues to run.  It will exit when it sees
    3865             :      * EOF on its input pipe, which happens when there are no more upstream
    3866             :      * processes.
    3867             :      */
    3868       12538 :     if (Shutdown > NoShutdown && pmState == PM_NO_CHILDREN)
    3869             :     {
    3870         568 :         if (FatalError)
    3871             :         {
    3872           0 :             ereport(LOG, (errmsg("abnormal database system shutdown")));
    3873           0 :             ExitPostmaster(1);
    3874             :         }
    3875             :         else
    3876             :         {
    3877             :             /*
    3878             :              * Terminate exclusive backup mode to avoid recovery after a clean
    3879             :              * fast shutdown.  Since an exclusive backup can only be taken
    3880             :              * during normal running (and not, for example, while running
    3881             :              * under Hot Standby) it only makes sense to do this if we reached
    3882             :              * normal running. If we're still in recovery, the backup file is
    3883             :              * one we're recovering *from*, and we must keep it around so that
    3884             :              * recovery restarts from the right place.
    3885             :              */
    3886         568 :             if (ReachedNormalRunning)
    3887         490 :                 CancelBackup();
    3888             : 
    3889             :             /* Normal exit from the postmaster is here */
    3890         568 :             ExitPostmaster(0);
    3891             :         }
    3892             :     }
    3893             : 
    3894             :     /*
    3895             :      * If the startup process failed, or the user does not want an automatic
    3896             :      * restart after backend crashes, wait for all non-syslogger children to
    3897             :      * exit, and then exit postmaster.  We don't try to reinitialize when the
    3898             :      * startup process fails, because more than likely it will just fail again
    3899             :      * and we will keep trying forever.
    3900             :      */
    3901       11974 :     if (pmState == PM_NO_CHILDREN &&
    3902           8 :         (StartupStatus == STARTUP_CRASHED || !restart_after_crash))
    3903           0 :         ExitPostmaster(1);
    3904             : 
    3905             :     /*
    3906             :      * If we need to recover from a crash, wait for all non-syslogger children
    3907             :      * to exit, then reset shmem and StartupDataBase.
    3908             :      */
    3909       11970 :     if (FatalError && pmState == PM_NO_CHILDREN)
    3910             :     {
    3911           4 :         ereport(LOG,
    3912             :                 (errmsg("all server processes terminated; reinitializing")));
    3913             : 
    3914             :         /* allow background workers to immediately restart */
    3915           4 :         ResetBackgroundWorkerCrashTimes();
    3916             : 
    3917           4 :         shmem_exit(1);
    3918             : 
    3919             :         /* re-read control file into local memory */
    3920           4 :         LocalProcessControlFile(true);
    3921             : 
    3922           4 :         reset_shared(PostPortNumber);
    3923             : 
    3924           4 :         StartupPID = StartupDataBase();
    3925             :         Assert(StartupPID != 0);
    3926           4 :         StartupStatus = STARTUP_RUNNING;
    3927           4 :         pmState = PM_STARTUP;
    3928             :         /* crash recovery started, reset SIGKILL flag */
    3929           4 :         AbortStartTime = 0;
    3930             :     }
    3931       11970 : }
    3932             : 
    3933             : 
    3934             : /*
    3935             :  * Send a signal to a postmaster child process
    3936             :  *
    3937             :  * On systems that have setsid(), each child process sets itself up as a
    3938             :  * process group leader.  For signals that are generally interpreted in the
    3939             :  * appropriate fashion, we signal the entire process group not just the
    3940             :  * direct child process.  This allows us to, for example, SIGQUIT a blocked
    3941             :  * archive_recovery script, or SIGINT a script being run by a backend via
    3942             :  * system().
    3943             :  *
    3944             :  * There is a race condition for recently-forked children: they might not
    3945             :  * have executed setsid() yet.  So we signal the child directly as well as
    3946             :  * the group.  We assume such a child will handle the signal before trying
    3947             :  * to spawn any grandchild processes.  We also assume that signaling the
    3948             :  * child twice will not cause any problems.
    3949             :  */
    3950             : static void
    3951        4146 : signal_child(pid_t pid, int signal)
    3952             : {
    3953        4146 :     if (kill(pid, signal) < 0)
    3954           0 :         elog(DEBUG3, "kill(%ld,%d) failed: %m", (long) pid, signal);
    3955             : #ifdef HAVE_SETSID
    3956        4146 :     switch (signal)
    3957             :     {
    3958             :         case SIGINT:
    3959             :         case SIGTERM:
    3960             :         case SIGQUIT:
    3961             :         case SIGSTOP:
    3962             :         case SIGKILL:
    3963        3280 :             if (kill(-pid, signal) < 0)
    3964           8 :                 elog(DEBUG3, "kill(%ld,%d) failed: %m", (long) (-pid), signal);
    3965        3280 :             break;
    3966             :         default:
    3967         866 :             break;
    3968             :     }
    3969             : #endif
    3970        4146 : }
    3971             : 
    3972             : /*
    3973             :  * Send a signal to the targeted children (but NOT special children;
    3974             :  * dead_end children are never signaled, either).
    3975             :  */
    3976             : static bool
    3977         992 : SignalSomeChildren(int signal, int target)
    3978             : {
    3979             :     dlist_iter  iter;
    3980         992 :     bool        signaled = false;
    3981             : 
    3982        2048 :     dlist_foreach(iter, &BackendList)
    3983             :     {
    3984        1056 :         Backend    *bp = dlist_container(Backend, elem, iter.cur);
    3985             : 
    3986        1056 :         if (bp->dead_end)
    3987           0 :             continue;
    3988             : 
    3989             :         /*
    3990             :          * Since target == BACKEND_TYPE_ALL is the most common case, we test
    3991             :          * it first and avoid touching shared memory for every child.
    3992             :          */
    3993        1056 :         if (target != BACKEND_TYPE_ALL)
    3994             :         {
    3995             :             /*
    3996             :              * Assign bkend_type for any recently announced WAL Sender
    3997             :              * processes.
    3998             :              */
    3999         874 :             if (bp->bkend_type == BACKEND_TYPE_NORMAL &&
    4000         248 :                 IsPostmasterChildWalSender(bp->child_slot))
    4001          34 :                 bp->bkend_type = BACKEND_TYPE_WALSND;
    4002             : 
    4003         626 :             if (!(target & bp->bkend_type))
    4004          42 :                 continue;
    4005             :         }
    4006             : 
    4007        1014 :         ereport(DEBUG4,
    4008             :                 (errmsg_internal("sending signal %d to process %d",
    4009             :                                  signal, (int) bp->pid)));
    4010        1014 :         signal_child(bp->pid, signal);
    4011        1014 :         signaled = true;
    4012             :     }
    4013         992 :     return signaled;
    4014             : }
    4015             : 
    4016             : /*
    4017             :  * Send a termination signal to children.  This considers all of our children
    4018             :  * processes, except syslogger and dead_end backends.
    4019             :  */
    4020             : static void
    4021         192 : TerminateChildren(int signal)
    4022             : {
    4023         192 :     SignalChildren(signal);
    4024         192 :     if (StartupPID != 0)
    4025             :     {
    4026          56 :         signal_child(StartupPID, signal);
    4027          56 :         if (signal == SIGQUIT || signal == SIGKILL)
    4028          56 :             StartupStatus = STARTUP_SIGNALED;
    4029             :     }
    4030         192 :     if (BgWriterPID != 0)
    4031         192 :         signal_child(BgWriterPID, signal);
    4032         192 :     if (CheckpointerPID != 0)
    4033         192 :         signal_child(CheckpointerPID, signal);
    4034         192 :     if (WalWriterPID != 0)
    4035         136 :         signal_child(WalWriterPID, signal);
    4036         192 :     if (WalReceiverPID != 0)
    4037          20 :         signal_child(WalReceiverPID, signal);
    4038         192 :     if (AutoVacPID != 0)
    4039         130 :         signal_child(AutoVacPID, signal);
    4040         192 :     if (PgArchPID != 0)
    4041          10 :         signal_child(PgArchPID, signal);
    4042         192 :     if (PgStatPID != 0)
    4043         192 :         signal_child(PgStatPID, signal);
    4044         192 : }
    4045             : 
    4046             : /*
    4047             :  * BackendStartup -- start backend process
    4048             :  *
    4049             :  * returns: STATUS_ERROR if the fork failed, STATUS_OK otherwise.
    4050             :  *
    4051             :  * Note: if you change this code, also consider StartAutovacuumWorker.
    4052             :  */
    4053             : static int
    4054        6870 : BackendStartup(Port *port)
    4055             : {
    4056             :     Backend    *bn;             /* for backend cleanup */
    4057             :     pid_t       pid;
    4058             : 
    4059             :     /*
    4060             :      * Create backend data structure.  Better before the fork() so we can
    4061             :      * handle failure cleanly.
    4062             :      */
    4063        6870 :     bn = (Backend *) malloc(sizeof(Backend));
    4064        6870 :     if (!bn)
    4065             :     {
    4066           0 :         ereport(LOG,
    4067             :                 (errcode(ERRCODE_OUT_OF_MEMORY),
    4068             :                  errmsg("out of memory")));
    4069           0 :         return STATUS_ERROR;
    4070             :     }
    4071             : 
    4072             :     /*
    4073             :      * Compute the cancel key that will be assigned to this backend. The
    4074             :      * backend will have its own copy in the forked-off process' value of
    4075             :      * MyCancelKey, so that it can transmit the key to the frontend.
    4076             :      */
    4077        6870 :     if (!RandomCancelKey(&MyCancelKey))
    4078             :     {
    4079           0 :         free(bn);
    4080           0 :         ereport(LOG,
    4081             :                 (errcode(ERRCODE_INTERNAL_ERROR),
    4082             :                  errmsg("could not generate random cancel key")));
    4083           0 :         return STATUS_ERROR;
    4084             :     }
    4085             : 
    4086        6870 :     bn->cancel_key = MyCancelKey;
    4087             : 
    4088             :     /* Pass down canAcceptConnections state */
    4089        6870 :     port->canAcceptConnections = canAcceptConnections();
    4090        6950 :     bn->dead_end = (port->canAcceptConnections != CAC_OK &&
    4091          80 :                     port->canAcceptConnections != CAC_WAITBACKUP);
    4092             : 
    4093             :     /*
    4094             :      * Unless it's a dead_end child, assign it a child slot number
    4095             :      */
    4096        6870 :     if (!bn->dead_end)
    4097        6790 :         bn->child_slot = MyPMChildSlot = AssignPostmasterChildSlot();
    4098             :     else
    4099          80 :         bn->child_slot = 0;
    4100             : 
    4101             :     /* Hasn't asked to be notified about any bgworkers yet */
    4102        6870 :     bn->bgworker_notify = false;
    4103             : 
    4104             : #ifdef EXEC_BACKEND
    4105             :     pid = backend_forkexec(port);
    4106             : #else                           /* !EXEC_BACKEND */
    4107        6870 :     pid = fork_process();
    4108       13626 :     if (pid == 0)               /* child */
    4109             :     {
    4110        6758 :         free(bn);
    4111             : 
    4112             :         /* Detangle from postmaster */
    4113        6758 :         InitPostmasterChild();
    4114             : 
    4115             :         /* Close the postmaster's sockets */
    4116        6758 :         ClosePostmasterPorts(false);
    4117             : 
    4118             :         /* Perform additional initialization and collect startup packet */
    4119        6758 :         BackendInitialize(port);
    4120             : 
    4121             :         /* And run the backend */
    4122        6642 :         BackendRun(port);
    4123             :     }
    4124             : #endif                          /* EXEC_BACKEND */
    4125             : 
    4126        6868 :     if (pid < 0)
    4127             :     {
    4128             :         /* in parent, fork failed */
    4129           0 :         int         save_errno = errno;
    4130             : 
    4131           0 :         if (!bn->dead_end)
    4132           0 :             (void) ReleasePostmasterChildSlot(bn->child_slot);
    4133           0 :         free(bn);
    4134           0 :         errno = save_errno;
    4135           0 :         ereport(LOG,
    4136             :                 (errmsg("could not fork new process for connection: %m")));
    4137           0 :         report_fork_failure_to_client(port, save_errno);
    4138           0 :         return STATUS_ERROR;
    4139             :     }
    4140             : 
    4141             :     /* in parent, successful fork */
    4142        6868 :     ereport(DEBUG2,
    4143             :             (errmsg_internal("forked new backend, pid=%d socket=%d",
    4144             :                              (int) pid, (int) port->sock)));
    4145             : 
    4146             :     /*
    4147             :      * Everything's been successful, it's safe to add this backend to our list
    4148             :      * of backends.
    4149             :      */
    4150        6868 :     bn->pid = pid;
    4151        6868 :     bn->bkend_type = BACKEND_TYPE_NORMAL;    /* Can change later to WALSND */
    4152        6868 :     dlist_push_head(&BackendList, &bn->elem);
    4153             : 
    4154             : #ifdef EXEC_BACKEND
    4155             :     if (!bn->dead_end)
    4156             :         ShmemBackendArrayAdd(bn);
    4157             : #endif
    4158             : 
    4159        6868 :     return STATUS_OK;
    4160             : }
    4161             : 
    4162             : /*
    4163             :  * Try to report backend fork() failure to client before we close the
    4164             :  * connection.  Since we do not care to risk blocking the postmaster on
    4165             :  * this connection, we set the connection to non-blocking and try only once.
    4166             :  *
    4167             :  * This is grungy special-purpose code; we cannot use backend libpq since
    4168             :  * it's not up and running.
    4169             :  */
    4170             : static void
    4171           0 : report_fork_failure_to_client(Port *port, int errnum)
    4172             : {
    4173             :     char        buffer[1000];
    4174             :     int         rc;
    4175             : 
    4176             :     /* Format the error message packet (always V2 protocol) */
    4177           0 :     snprintf(buffer, sizeof(buffer), "E%s%s\n",
    4178             :              _("could not fork new process for connection: "),
    4179             :              strerror(errnum));
    4180             : 
    4181             :     /* Set port to non-blocking.  Don't do send() if this fails */
    4182           0 :     if (!pg_set_noblock(port->sock))
    4183           0 :         return;
    4184             : 
    4185             :     /* We'll retry after EINTR, but ignore all other failures */
    4186             :     do
    4187             :     {
    4188           0 :         rc = send(port->sock, buffer, strlen(buffer) + 1, 0);
    4189           0 :     } while (rc < 0 && errno == EINTR);
    4190             : }
    4191             : 
    4192             : 
    4193             : /*
    4194             :  * BackendInitialize -- initialize an interactive (postmaster-child)
    4195             :  *              backend process, and collect the client's startup packet.
    4196             :  *
    4197             :  * returns: nothing.  Will not return at all if there's any failure.
    4198             :  *
    4199             :  * Note: this code does not depend on having any access to shared memory.
    4200             :  * In the EXEC_BACKEND case, we are physically attached to shared memory
    4201             :  * but have not yet set up most of our local pointers to shmem structures.
    4202             :  */
    4203             : static void
    4204        6758 : BackendInitialize(Port *port)
    4205             : {
    4206             :     int         status;
    4207             :     int         ret;
    4208             :     char        remote_host[NI_MAXHOST];
    4209             :     char        remote_port[NI_MAXSERV];
    4210             :     char        remote_ps_data[NI_MAXHOST];
    4211             : 
    4212             :     /* Save port etc. for ps status */
    4213        6758 :     MyProcPort = port;
    4214             : 
    4215             :     /*
    4216             :      * PreAuthDelay is a debugging aid for investigating problems in the
    4217             :      * authentication cycle: it can be set in postgresql.conf to allow time to
    4218             :      * attach to the newly-forked backend with a debugger.  (See also
    4219             :      * PostAuthDelay, which we allow clients to pass through PGOPTIONS, but it
    4220             :      * is not honored until after authentication.)
    4221             :      */
    4222        6758 :     if (PreAuthDelay > 0)
    4223           0 :         pg_usleep(PreAuthDelay * 1000000L);
    4224             : 
    4225             :     /* This flag will remain set until InitPostgres finishes authentication */
    4226        6758 :     ClientAuthInProgress = true;    /* limit visibility of log messages */
    4227             : 
    4228             :     /* set these to empty in case they are needed before we set them up */
    4229        6758 :     port->remote_host = "";
    4230        6758 :     port->remote_port = "";
    4231             : 
    4232             :     /*
    4233             :      * Initialize libpq and enable reporting of ereport errors to the client.
    4234             :      * Must do this now because authentication uses libpq to send messages.
    4235             :      */
    4236        6758 :     pq_init();                  /* initialize libpq to talk to client */
    4237        6758 :     whereToSendOutput = DestRemote; /* now safe to ereport to client */
    4238             : 
    4239             :     /*
    4240             :      * We arrange for a simple exit(1) if we receive SIGTERM or SIGQUIT or
    4241             :      * timeout while trying to collect the startup packet.  Otherwise the
    4242             :      * postmaster cannot shutdown the database FAST or IMMED cleanly if a
    4243             :      * buggy client fails to send the packet promptly.  XXX it follows that
    4244             :      * the remainder of this function must tolerate losing control at any
    4245             :      * instant.  Likewise, any pg_on_exit_callback registered before or during
    4246             :      * this function must be prepared to execute at any instant between here
    4247             :      * and the end of this function.  Furthermore, affected callbacks execute
    4248             :      * partially or not at all when a second exit-inducing signal arrives
    4249             :      * after proc_exit_prepare() decrements on_proc_exit_index.  (Thanks to
    4250             :      * that mechanic, callbacks need not anticipate more than one call.)  This
    4251             :      * is fragile; it ought to instead follow the norm of handling interrupts
    4252             :      * at selected, safe opportunities.
    4253             :      */
    4254        6758 :     pqsignal(SIGTERM, startup_die);
    4255        6758 :     pqsignal(SIGQUIT, startup_die);
    4256        6758 :     InitializeTimeouts();       /* establishes SIGALRM handler */
    4257        6758 :     PG_SETMASK(&StartupBlockSig);
    4258             : 
    4259             :     /*
    4260             :      * Get the remote host name and port for logging and status display.
    4261             :      */
    4262        6756 :     remote_host[0] = '\0';
    4263        6756 :     remote_port[0] = '\0';
    4264        6756 :     if ((ret = pg_getnameinfo_all(&port->raddr.addr, port->raddr.salen,
    4265             :                                   remote_host, sizeof(remote_host),
    4266             :                                   remote_port, sizeof(remote_port),
    4267             :                                   (log_hostname ? 0 : NI_NUMERICHOST) | NI_NUMERICSERV)) != 0)
    4268           0 :         ereport(WARNING,
    4269             :                 (errmsg_internal("pg_getnameinfo_all() failed: %s",
    4270             :                                  gai_strerror(ret))));
    4271        6756 :     if (remote_port[0] == '\0')
    4272        6374 :         snprintf(remote_ps_data, sizeof(remote_ps_data), "%s", remote_host);
    4273             :     else
    4274         382 :         snprintf(remote_ps_data, sizeof(remote_ps_data), "%s(%s)", remote_host, remote_port);
    4275             : 
    4276             :     /*
    4277             :      * Save remote_host and remote_port in port structure (after this, they
    4278             :      * will appear in log_line_prefix data for log messages).
    4279             :      */
    4280        6756 :     port->remote_host = strdup(remote_host);
    4281        6756 :     port->remote_port = strdup(remote_port);
    4282             : 
    4283             :     /* And now we can issue the Log_connections message, if wanted */
    4284        6756 :     if (Log_connections)
    4285             :     {
    4286         106 :         if (remote_port[0])
    4287          86 :             ereport(LOG,
    4288             :                     (errmsg("connection received: host=%s port=%s",
    4289             :                             remote_host,
    4290             :                             remote_port)));
    4291             :         else
    4292          20 :             ereport(LOG,
    4293             :                     (errmsg("connection received: host=%s",
    4294             :                             remote_host)));
    4295             :     }
    4296             : 
    4297             :     /*
    4298             :      * If we did a reverse lookup to name, we might as well save the results
    4299             :      * rather than possibly repeating the lookup during authentication.
    4300             :      *
    4301             :      * Note that we don't want to specify NI_NAMEREQD above, because then we'd
    4302             :      * get nothing useful for a client without an rDNS entry.  Therefore, we
    4303             :      * must check whether we got a numeric IPv4 or IPv6 address, and not save
    4304             :      * it into remote_hostname if so.  (This test is conservative and might
    4305             :      * sometimes classify a hostname as numeric, but an error in that
    4306             :      * direction is safe; it only results in a possible extra lookup.)
    4307             :      */
    4308        6756 :     if (log_hostname &&
    4309          86 :         ret == 0 &&
    4310         172 :         strspn(remote_host, "0123456789.") < strlen(remote_host) &&
    4311          86 :         strspn(remote_host, "0123456789ABCDEFabcdef:") < strlen(remote_host))
    4312          86 :         port->remote_hostname = strdup(remote_host);
    4313             : 
    4314             :     /*
    4315             :      * Ready to begin client interaction.  We will give up and exit(1) after a
    4316             :      * time delay, so that a broken client can't hog a connection
    4317             :      * indefinitely.  PreAuthDelay and any DNS interactions above don't count
    4318             :      * against the time limit.
    4319             :      *
    4320             :      * Note: AuthenticationTimeout is applied here while waiting for the
    4321             :      * startup packet, and then again in InitPostgres for the duration of any
    4322             :      * authentication operations.  So a hostile client could tie up the
    4323             :      * process for nearly twice AuthenticationTimeout before we kick him off.
    4324             :      *
    4325             :      * Note: because PostgresMain will call InitializeTimeouts again, the
    4326             :      * registration of STARTUP_PACKET_TIMEOUT will be lost.  This is okay
    4327             :      * since we never use it again after this function.
    4328             :      */
    4329        6756 :     RegisterTimeout(STARTUP_PACKET_TIMEOUT, StartupPacketTimeoutHandler);
    4330        6756 :     enable_timeout_after(STARTUP_PACKET_TIMEOUT, AuthenticationTimeout * 1000);
    4331             : 
    4332             :     /*
    4333             :      * Receive the startup packet (which might turn out to be a cancel request
    4334             :      * packet).
    4335             :      */
    4336        6756 :     status = ProcessStartupPacket(port, false);
    4337             : 
    4338             :     /*
    4339             :      * Stop here if it was bad or a cancel packet.  ProcessStartupPacket
    4340             :      * already did any appropriate error reporting.
    4341             :      */
    4342        6676 :     if (status != STATUS_OK)
    4343          34 :         proc_exit(0);
    4344             : 
    4345             :     /*
    4346             :      * Now that we have the user and database name, we can set the process
    4347             :      * title for ps.  It's good to do this as early as possible in startup.
    4348             :      *
    4349             :      * For a walsender, the ps display is set in the following form:
    4350             :      *
    4351             :      * postgres: walsender <user> <host> <activity>
    4352             :      *
    4353             :      * To achieve that, we pass "walsender" as username and username as dbname
    4354             :      * to init_ps_display(). XXX: should add a new variant of
    4355             :      * init_ps_display() to avoid abusing the parameters like this.
    4356             :      */
    4357        6642 :     if (am_walsender)
    4358         466 :         init_ps_display(pgstat_get_backend_desc(B_WAL_SENDER), port->user_name, remote_ps_data,
    4359         466 :                         update_process_title ? "authentication" : "");
    4360             :     else
    4361        6176 :         init_ps_display(port->user_name, port->database_name, remote_ps_data,
    4362        6176 :                         update_process_title ? "authentication" : "");
    4363             : 
    4364             :     /*
    4365             :      * Disable the timeout, and prevent SIGTERM/SIGQUIT again.
    4366             :      */
    4367        6642 :     disable_timeout(STARTUP_PACKET_TIMEOUT, false);
    4368        6642 :     PG_SETMASK(&BlockSig);
    4369        6642 : }
    4370             : 
    4371             : 
    4372             : /*
    4373             :  * BackendRun -- set up the backend's argument list and invoke PostgresMain()
    4374             :  *
    4375             :  * returns:
    4376             :  *      Shouldn't return at all.
    4377             :  *      If PostgresMain() fails, return status.
    4378             :  */
    4379             : static void
    4380        6642 : BackendRun(Port *port)
    4381             : {
    4382             :     char      **av;
    4383             :     int         maxac;
    4384             :     int         ac;
    4385             :     int         i;
    4386             : 
    4387             :     /*
    4388             :      * Now, build the argv vector that will be given to PostgresMain.
    4389             :      *
    4390             :      * The maximum possible number of commandline arguments that could come
    4391             :      * from ExtraOptions is (strlen(ExtraOptions) + 1) / 2; see
    4392             :      * pg_split_opts().
    4393             :      */
    4394        6642 :     maxac = 2;                  /* for fixed args supplied below */
    4395        6642 :     maxac += (strlen(ExtraOptions) + 1) / 2;
    4396             : 
    4397        6642 :     av = (char **) MemoryContextAlloc(TopMemoryContext,
    4398             :                                       maxac * sizeof(char *));
    4399        6642 :     ac = 0;
    4400             : 
    4401        6642 :     av[ac++] = "postgres";
    4402             : 
    4403             :     /*
    4404             :      * Pass any backend switches specified with -o on the postmaster's own
    4405             :      * command line.  We assume these are secure.
    4406             :      */
    4407        6642 :     pg_split_opts(av, &ac, ExtraOptions);
    4408             : 
    4409        6642 :     av[ac] = NULL;
    4410             : 
    4411             :     Assert(ac < maxac);
    4412             : 
    4413             :     /*
    4414             :      * Debug: print arguments being passed to backend
    4415             :      */
    4416        6642 :     ereport(DEBUG3,
    4417             :             (errmsg_internal("%s child[%d]: starting with (",
    4418             :                              progname, (int) getpid())));
    4419       13284 :     for (i = 0; i < ac; ++i)
    4420        6642 :         ereport(DEBUG3,
    4421             :                 (errmsg_internal("\t%s", av[i])));
    4422        6642 :     ereport(DEBUG3,
    4423             :             (errmsg_internal(")")));
    4424             : 
    4425             :     /*
    4426             :      * Make sure we aren't in PostmasterContext anymore.  (We can't delete it
    4427             :      * just yet, though, because InitPostgres will need the HBA data.)
    4428             :      */
    4429        6642 :     MemoryContextSwitchTo(TopMemoryContext);
    4430             : 
    4431        6642 :     PostgresMain(ac, av, port->database_name, port->user_name);
    4432             : }
    4433             : 
    4434             : 
    4435             : #ifdef EXEC_BACKEND
    4436             : 
    4437             : /*
    4438             :  * postmaster_forkexec -- fork and exec a postmaster subprocess
    4439             :  *
    4440             :  * The caller must have set up the argv array already, except for argv[2]
    4441             :  * which will be filled with the name of the temp variable file.
    4442             :  *
    4443             :  * Returns the child process PID, or -1 on fork failure (a suitable error
    4444             :  * message has been logged on failure).
    4445             :  *
    4446             :  * All uses of this routine will dispatch to SubPostmasterMain in the
    4447             :  * child process.
    4448             :  */
    4449             : pid_t
    4450             : postmaster_forkexec(int argc, char *argv[])
    4451             : {
    4452             :     Port        port;
    4453             : 
    4454             :     /* This entry point passes dummy values for the Port variables */
    4455             :     memset(&port, 0, sizeof(port));
    4456             :     return internal_forkexec(argc, argv, &port);
    4457             : }
    4458             : 
    4459             : /*
    4460             :  * backend_forkexec -- fork/exec off a backend process
    4461             :  *
    4462             :  * Some operating systems (WIN32) don't have fork() so we have to simulate
    4463             :  * it by storing parameters that need to be passed to the child and
    4464             :  * then create a new child process.
    4465             :  *
    4466             :  * returns the pid of the fork/exec'd process, or -1 on failure
    4467             :  */
    4468             : static pid_t
    4469             : backend_forkexec(Port *port)
    4470             : {
    4471             :     char       *av[4];
    4472             :     int         ac = 0;
    4473             : 
    4474             :     av[ac++] = "postgres";
    4475             :     av[ac++] = "--forkbackend";
    4476             :     av[ac++] = NULL;            /* filled in by internal_forkexec */
    4477             : 
    4478             :     av[ac] = NULL;
    4479             :     Assert(ac < lengthof(av));
    4480             : 
    4481             :     return internal_forkexec(ac, av, port);
    4482             : }
    4483             : 
    4484             : #ifndef WIN32
    4485             : 
    4486             : /*
    4487             :  * internal_forkexec non-win32 implementation
    4488             :  *
    4489             :  * - writes out backend variables to the parameter file
    4490             :  * - fork():s, and then exec():s the child process
    4491             :  */
    4492             : static pid_t
    4493             : internal_forkexec(int argc, char *argv[], Port *port)
    4494             : {
    4495             :     static unsigned long tmpBackendFileNum = 0;
    4496             :     pid_t       pid;
    4497             :     char        tmpfilename[MAXPGPATH];
    4498             :     BackendParameters param;
    4499             :     FILE       *fp;
    4500             : 
    4501             :     if (!save_backend_variables(&param, port))
    4502             :         return -1;              /* log made by save_backend_variables */
    4503             : 
    4504             :     /* Calculate name for temp file */
    4505             :     snprintf(tmpfilename, MAXPGPATH, "%s/%s.backend_var.%d.%lu",
    4506             :              PG_TEMP_FILES_DIR, PG_TEMP_FILE_PREFIX,
    4507             :              MyProcPid, ++tmpBackendFileNum);
    4508             : 
    4509             :     /* Open file */
    4510             :     fp = AllocateFile(tmpfilename, PG_BINARY_W);
    4511             :     if (!fp)
    4512             :     {
    4513             :         /*
    4514             :          * As in OpenTemporaryFileInTablespace, try to make the temp-file
    4515             :          * directory, ignoring errors.
    4516             :          */
    4517             :         (void) MakePGDirectory(PG_TEMP_FILES_DIR);
    4518             : 
    4519             :         fp = AllocateFile(tmpfilename, PG_BINARY_W);
    4520             :         if (!fp)
    4521             :         {
    4522             :             ereport(LOG,
    4523             :                     (errcode_for_file_access(),
    4524             :                      errmsg("could not create file \"%s\": %m",
    4525             :                             tmpfilename)));
    4526             :             return -1;
    4527             :         }
    4528             :     }
    4529             : 
    4530             :     if (fwrite(&param, sizeof(param), 1, fp) != 1)
    4531             :     {
    4532             :         ereport(LOG,
    4533             :                 (errcode_for_file_access(),
    4534             :                  errmsg("could not write to file \"%s\": %m", tmpfilename)));
    4535             :         FreeFile(fp);
    4536             :         return -1;
    4537             :     }
    4538             : 
    4539             :     /* Release file */
    4540             :     if (FreeFile(fp))
    4541             :     {
    4542             :         ereport(LOG,
    4543             :                 (errcode_for_file_access(),
    4544             :                  errmsg("could not write to file \"%s\": %m", tmpfilename)));
    4545             :         return -1;
    4546             :     }
    4547             : 
    4548             :     /* Make sure caller set up argv properly */
    4549             :     Assert(argc >= 3);
    4550             :     Assert(argv[argc] == NULL);
    4551             :     Assert(strncmp(argv[1], "--fork", 6) == 0);
    4552             :     Assert(argv[2] == NULL);
    4553             : 
    4554             :     /* Insert temp file name after --fork argument */
    4555             :     argv[2] = tmpfilename;
    4556             : 
    4557             :     /* Fire off execv in child */
    4558             :     if ((pid = fork_process()) == 0)
    4559             :     {
    4560             :         if (execv(postgres_exec_path, argv) < 0)
    4561             :         {
    4562             :             ereport(LOG,
    4563             :                     (errmsg("could not execute server process \"%s\": %m",
    4564             :                             postgres_exec_path)));
    4565             :             /* We're already in the child process here, can't return */
    4566             :             exit(1);
    4567             :         }
    4568             :     }
    4569             : 
    4570             :     return pid;                 /* Parent returns pid, or -1 on fork failure */
    4571             : }
    4572             : #else                           /* WIN32 */
    4573             : 
    4574             : /*
    4575             :  * internal_forkexec win32 implementation
    4576             :  *
    4577             :  * - starts backend using CreateProcess(), in suspended state
    4578             :  * - writes out backend variables to the parameter file
    4579             :  *  - during this, duplicates handles and sockets required for
    4580             :  *    inheritance into the new process
    4581             :  * - resumes execution of the new process once the backend parameter
    4582             :  *   file is complete.
    4583             :  */
    4584             : static pid_t
    4585             : internal_forkexec(int argc, char *argv[], Port *port)
    4586             : {
    4587             :     int         retry_count = 0;
    4588             :     STARTUPINFO si;
    4589             :     PROCESS_INFORMATION pi;
    4590             :     int         i;
    4591             :     int         j;
    4592             :     char        cmdLine[MAXPGPATH * 2];
    4593             :     HANDLE      paramHandle;
    4594             :     BackendParameters *param;
    4595             :     SECURITY_ATTRIBUTES sa;
    4596             :     char        paramHandleStr[32];
    4597             :     win32_deadchild_waitinfo *childinfo;
    4598             : 
    4599             :     /* Make sure caller set up argv properly */
    4600             :     Assert(argc >= 3);
    4601             :     Assert(argv[argc] == NULL);
    4602             :     Assert(strncmp(argv[1], "--fork", 6) == 0);
    4603             :     Assert(argv[2] == NULL);
    4604             : 
    4605             :     /* Resume here if we need to retry */
    4606             : retry:
    4607             : 
    4608             :     /* Set up shared memory for parameter passing */
    4609             :     ZeroMemory(&sa, sizeof(sa));
    4610             :     sa.nLength = sizeof(sa);
    4611             :     sa.bInheritHandle = TRUE;
    4612             :     paramHandle = CreateFileMapping(INVALID_HANDLE_VALUE,
    4613             :                                     &sa,
    4614             :                                     PAGE_READWRITE,
    4615             :                                     0,
    4616             :                                     sizeof(BackendParameters),
    4617             :                                     NULL);
    4618             :     if (paramHandle == INVALID_HANDLE_VALUE)
    4619             :     {
    4620             :         elog(LOG, "could not create backend parameter file mapping: error code %lu",
    4621             :              GetLastError());
    4622             :         return -1;
    4623             :     }
    4624             : 
    4625             :     param = MapViewOfFile(paramHandle, FILE_MAP_WRITE, 0, 0, sizeof(BackendParameters));
    4626             :     if (!param)
    4627             :     {
    4628             :         elog(LOG, "could not map backend parameter memory: error code %lu",
    4629             :              GetLastError());
    4630             :         CloseHandle(paramHandle);
    4631             :         return -1;
    4632             :     }
    4633             : 
    4634             :     /* Insert temp file name after --fork argument */
    4635             : #ifdef _WIN64
    4636             :     sprintf(paramHandleStr, "%llu", (LONG_PTR) paramHandle);
    4637             : #else
    4638             :     sprintf(paramHandleStr, "%lu", (DWORD) paramHandle);
    4639             : #endif
    4640             :     argv[2] = paramHandleStr;
    4641             : 
    4642             :     /* Format the cmd line */
    4643             :     cmdLine[sizeof(cmdLine) - 1] = '\0';
    4644             :     cmdLine[sizeof(cmdLine) - 2] = '\0';
    4645             :     snprintf(cmdLine, sizeof(cmdLine) - 1, "\"%s\"", postgres_exec_path);
    4646             :     i = 0;
    4647             :     while (argv[++i] != NULL)
    4648             :     {
    4649             :         j = strlen(cmdLine);
    4650             :         snprintf(cmdLine + j, sizeof(cmdLine) - 1 - j, " \"%s\"", argv[i]);
    4651             :     }
    4652             :     if (cmdLine[sizeof(cmdLine) - 2] != '\0')
    4653             :     {
    4654             :         elog(LOG, "subprocess command line too long");
    4655             :         return -1;
    4656             :     }
    4657             : 
    4658             :     memset(&pi, 0, sizeof(pi));
    4659             :     memset(&si, 0, sizeof(si));
    4660             :     si.cb = sizeof(si);
    4661             : 
    4662             :     /*
    4663             :      * Create the subprocess in a suspended state. This will be resumed later,
    4664             :      * once we have written out the parameter file.
    4665             :      */
    4666             :     if (!CreateProcess(NULL, cmdLine, NULL, NULL, TRUE, CREATE_SUSPENDED,
    4667             :                        NULL, NULL, &si, &pi))
    4668             :     {
    4669             :         elog(LOG, "CreateProcess call failed: %m (error code %lu)",
    4670             :              GetLastError());
    4671             :         return -1;
    4672             :     }
    4673             : 
    4674             :     if (!save_backend_variables(param, port, pi.hProcess, pi.dwProcessId))
    4675             :     {
    4676             :         /*
    4677             :          * log made by save_backend_variables, but we have to clean up the
    4678             :          * mess with the half-started process
    4679             :          */
    4680             :         if (!TerminateProcess(pi.hProcess, 255))
    4681             :             ereport(LOG,
    4682             :                     (errmsg_internal("could not terminate unstarted process: error code %lu",
    4683             :                                      GetLastError())));
    4684             :         CloseHandle(pi.hProcess);
    4685             :         CloseHandle(pi.hThread);
    4686             :         return -1;              /* log made by save_backend_variables */
    4687             :     }
    4688             : 
    4689             :     /* Drop the parameter shared memory that is now inherited to the backend */
    4690             :     if (!UnmapViewOfFile(param))
    4691             :         elog(LOG, "could not unmap view of backend parameter file: error code %lu",
    4692             :              GetLastError());
    4693             :     if (!CloseHandle(paramHandle))
    4694             :         elog(LOG, "could not close handle to backend parameter file: error code %lu",
    4695             :              GetLastError());
    4696             : 
    4697             :     /*
    4698             :      * Reserve the memory region used by our main shared memory segment before
    4699             :      * we resume the child process.  Normally this should succeed, but if ASLR
    4700             :      * is active then it might sometimes fail due to the stack or heap having
    4701             :      * gotten mapped into that range.  In that case, just terminate the
    4702             :      * process and retry.
    4703             :      */
    4704             :     if (!pgwin32_ReserveSharedMemoryRegion(pi.hProcess))
    4705             :     {
    4706             :         /* pgwin32_ReserveSharedMemoryRegion already made a log entry */
    4707             :         if (!TerminateProcess(pi.hProcess, 255))
    4708             :             ereport(LOG,
    4709             :                     (errmsg_internal("could not terminate process that failed to reserve memory: error code %lu",
    4710             :                                      GetLastError())));
    4711             :         CloseHandle(pi.hProcess);
    4712             :         CloseHandle(pi.hThread);
    4713             :         if (++retry_count < 100)
    4714             :             goto retry;
    4715             :         ereport(LOG,
    4716             :                 (errmsg("giving up after too many tries to reserve shared memory"),
    4717             :                  errhint("This might be caused by ASLR or antivirus software.")));
    4718             :         return -1;
    4719             :     }
    4720             : 
    4721             :     /*
    4722             :      * Now that the backend variables are written out, we start the child
    4723             :      * thread so it can start initializing while we set up the rest of the
    4724             :      * parent state.
    4725             :      */
    4726             :     if (ResumeThread(pi.hThread) == -1)
    4727             :     {
    4728             :         if (!TerminateProcess(pi.hProcess, 255))
    4729             :         {
    4730             :             ereport(LOG,
    4731             :                     (errmsg_internal("could not terminate unstartable process: error code %lu",
    4732             :                                      GetLastError())));
    4733             :             CloseHandle(pi.hProcess);
    4734             :             CloseHandle(pi.hThread);
    4735             :             return -1;
    4736             :         }
    4737             :         CloseHandle(pi.hProcess);
    4738             :         CloseHandle(pi.hThread);
    4739             :         ereport(LOG,
    4740             :                 (errmsg_internal("could not resume thread of unstarted process: error code %lu",
    4741             :                                  GetLastError())));
    4742             :         return -1;
    4743             :     }
    4744             : 
    4745             :     /*
    4746             :      * Queue a waiter to signal when this child dies. The wait will be handled
    4747             :      * automatically by an operating system thread pool.
    4748             :      *
    4749             :      * Note: use malloc instead of palloc, since it needs to be thread-safe.
    4750             :      * Struct will be free():d from the callback function that runs on a
    4751             :      * different thread.
    4752             :      */
    4753             :     childinfo = malloc(sizeof(win32_deadchild_waitinfo));
    4754             :     if (!childinfo)
    4755             :         ereport(FATAL,
    4756             :                 (errcode(ERRCODE_OUT_OF_MEMORY),
    4757             :                  errmsg("out of memory")));
    4758             : 
    4759             :     childinfo->procHandle = pi.hProcess;
    4760             :     childinfo->procId = pi.dwProcessId;
    4761             : 
    4762             :     if (!RegisterWaitForSingleObject(&childinfo->waitHandle,
    4763             :                                      pi.hProcess,
    4764             :                                      pgwin32_deadchild_callback,
    4765             :                                      childinfo,
    4766             :                                      INFINITE,
    4767             :                                      WT_EXECUTEONLYONCE | WT_EXECUTEINWAITTHREAD))
    4768             :         ereport(FATAL,
    4769             :                 (errmsg_internal("could not register process for wait: error code %lu",
    4770             :                                  GetLastError())));
    4771             : 
    4772             :     /* Don't close pi.hProcess here - the wait thread needs access to it */
    4773             : 
    4774             :     CloseHandle(pi.hThread);
    4775             : 
    4776             :     return pi.dwProcessId;
    4777             : }
    4778             : #endif                          /* WIN32 */
    4779             : 
    4780             : 
    4781             : /*
    4782             :  * SubPostmasterMain -- Get the fork/exec'd process into a state equivalent
    4783             :  *          to what it would be if we'd simply forked on Unix, and then
    4784             :  *          dispatch to the appropriate place.
    4785             :  *
    4786             :  * The first two command line arguments are expected to be "--forkFOO"
    4787             :  * (where FOO indicates which postmaster child we are to become), and
    4788             :  * the name of a variables file that we can read to load data that would
    4789             :  * have been inherited by fork() on Unix.  Remaining arguments go to the
    4790             :  * subprocess FooMain() routine.
    4791             :  */
    4792             : void
    4793             : SubPostmasterMain(int argc, char *argv[])
    4794             : {
    4795             :     Port        port;
    4796             : 
    4797             :     /* In EXEC_BACKEND case we will not have inherited these settings */
    4798             :     IsPostmasterEnvironment = true;
    4799             :     whereToSendOutput = DestNone;
    4800             : 
    4801             :     /* Setup as postmaster child */
    4802             :     InitPostmasterChild();
    4803             : 
    4804             :     /* Setup essential subsystems (to ensure elog() behaves sanely) */
    4805             :     InitializeGUCOptions();
    4806             : 
    4807             :     /* Check we got appropriate args */
    4808             :     if (argc < 3)
    4809             :         elog(FATAL, "invalid subpostmaster invocation");
    4810             : 
    4811             :     /* Read in the variables file */
    4812             :     memset(&port, 0, sizeof(Port));
    4813             :     read_backend_variables(argv[2], &port);
    4814             : 
    4815             :     /* Close the postmaster's sockets (as soon as we know them) */
    4816             :     ClosePostmasterPorts(strcmp(argv[1], "--forklog") == 0);
    4817             : 
    4818             :     /*
    4819             :      * Set reference point for stack-depth checking
    4820             :      */
    4821             :     set_stack_base();
    4822             : 
    4823             :     /*
    4824             :      * Set up memory area for GSS information. Mirrors the code in ConnCreate
    4825             :      * for the non-exec case.
    4826             :      */
    4827             : #if defined(ENABLE_GSS) || defined(ENABLE_SSPI)
    4828             :     port.gss = (pg_gssinfo *) calloc(1, sizeof(pg_gssinfo));
    4829             :     if (!port.gss)
    4830             :         ereport(FATAL,
    4831             :                 (errcode(ERRCODE_OUT_OF_MEMORY),
    4832             :                  errmsg("out of memory")));
    4833             : #endif
    4834             : 
    4835             :     /*
    4836             :      * If appropriate, physically re-attach to shared memory segment. We want
    4837             :      * to do this before going any further to ensure that we can attach at the
    4838             :      * same address the postmaster used.  On the other hand, if we choose not
    4839             :      * to re-attach, we may have other cleanup to do.
    4840             :      *
    4841             :      * If testing EXEC_BACKEND on Linux, you should run this as root before
    4842             :      * starting the postmaster:
    4843             :      *
    4844             :      * echo 0 >/proc/sys/kernel/randomize_va_space
    4845             :      *
    4846             :      * This prevents using randomized stack and code addresses that cause the
    4847             :      * child process's memory map to be different from the parent's, making it
    4848             :      * sometimes impossible to attach to shared memory at the desired address.
    4849             :      * Return the setting to its old value (usually '1' or '2') when finished.
    4850             :      */
    4851             :     if (strcmp(argv[1], "--forkbackend") == 0 ||
    4852             :         strcmp(argv[1], "--forkavlauncher") == 0 ||
    4853             :         strcmp(argv[1], "--forkavworker") == 0 ||
    4854             :         strcmp(argv[1], "--forkboot") == 0 ||
    4855             :         strncmp(argv[1], "--forkbgworker=", 15) == 0)
    4856             :         PGSharedMemoryReAttach();
    4857             :     else
    4858             :         PGSharedMemoryNoReAttach();
    4859             : 
    4860             :     /* autovacuum needs this set before calling InitProcess */
    4861             :     if (strcmp(argv[1], "--forkavlauncher") == 0)
    4862             :         AutovacuumLauncherIAm();
    4863             :     if (strcmp(argv[1], "--forkavworker") == 0)
    4864             :         AutovacuumWorkerIAm();
    4865             : 
    4866             :     /*
    4867             :      * Start our win32 signal implementation. This has to be done after we
    4868             :      * read the backend variables, because we need to pick up the signal pipe
    4869             :      * from the parent process.
    4870             :      */
    4871             : #ifdef WIN32
    4872             :     pgwin32_signal_initialize();
    4873             : #endif
    4874             : 
    4875             :     /* In EXEC_BACKEND case we will not have inherited these settings */
    4876             :     pqinitmask();
    4877             :     PG_SETMASK(&BlockSig);
    4878             : 
    4879             :     /* Read in remaining GUC variables */
    4880             :     read_nondefault_variables();
    4881             : 
    4882             :     /*
    4883             :      * Check that the data directory looks valid, which will also check the
    4884             :      * privileges on the data directory and update our umask and file/group
    4885             :      * variables for creating files later.  Note: this should really be done
    4886             :      * before we create any files or directories.
    4887             :      */
    4888             :     checkDataDir();
    4889             : 
    4890             :     /*
    4891             :      * (re-)read control file, as it contains config. The postmaster will
    4892             :      * already have read this, but this process doesn't know about that.
    4893             :      */
    4894             :     LocalProcessControlFile(false);
    4895             : 
    4896             :     /*
    4897             :      * Reload any libraries that were preloaded by the postmaster.  Since we
    4898             :      * exec'd this process, those libraries didn't come along with us; but we
    4899             :      * should load them into all child processes to be consistent with the
    4900             :      * non-EXEC_BACKEND behavior.
    4901             :      */
    4902             :     process_shared_preload_libraries();
    4903             : 
    4904             :     /* Run backend or appropriate child */
    4905             :     if (strcmp(argv[1], "--forkbackend") == 0)
    4906             :     {
    4907             :         Assert(argc == 3);      /* shouldn't be any more args */
    4908             : 
    4909             :         /*
    4910             :          * Need to reinitialize the SSL library in the backend, since the
    4911             :          * context structures contain function pointers and cannot be passed
    4912             :          * through the parameter file.
    4913             :          *
    4914             :          * If for some reason reload fails (maybe the user installed broken
    4915             :          * key files), soldier on without SSL; that's better than all
    4916             :          * connections becoming impossible.
    4917             :          *
    4918             :          * XXX should we do this in all child processes?  For the moment it's
    4919             :          * enough to do it in backend children.
    4920             :          */
    4921             : #ifdef USE_SSL
    4922             :         if (EnableSSL)
    4923             :         {
    4924             :             if (secure_initialize(false) == 0)
    4925             :                 LoadedSSL = true;
    4926             :             else
    4927             :                 ereport(LOG,
    4928             :                         (errmsg("SSL configuration could not be loaded in child process")));
    4929             :         }
    4930             : #endif
    4931             : 
    4932             :         /*
    4933             :          * Perform additional initialization and collect startup packet.
    4934             :          *
    4935             :          * We want to do this before InitProcess() for a couple of reasons: 1.
    4936             :          * so that we aren't eating up a PGPROC slot while waiting on the
    4937             :          * client. 2. so that if InitProcess() fails due to being out of
    4938             :          * PGPROC slots, we have already initialized libpq and are able to
    4939             :          * report the error to the client.
    4940             :          */
    4941             :         BackendInitialize(&port);
    4942             : 
    4943             :         /* Restore basic shared memory pointers */
    4944             :         InitShmemAccess(UsedShmemSegAddr);
    4945             : 
    4946             :         /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
    4947             :         InitProcess();
    4948             : 
    4949             :         /* Attach process to shared data structures */
    4950             :         CreateSharedMemoryAndSemaphores(0);
    4951             : 
    4952             :         /* And run the backend */
    4953             :         BackendRun(&port);      /* does not return */
    4954             :     }
    4955             :     if (strcmp(argv[1], "--forkboot") == 0)
    4956             :     {
    4957             :         /* Restore basic shared memory pointers */
    4958             :         InitShmemAccess(UsedShmemSegAddr);
    4959             : 
    4960             :         /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
    4961             :         InitAuxiliaryProcess();
    4962             : 
    4963             :         /* Attach process to shared data structures */
    4964             :         CreateSharedMemoryAndSemaphores(0);
    4965             : 
    4966             :         AuxiliaryProcessMain(argc - 2, argv + 2);   /* does not return */
    4967             :     }
    4968             :     if (strcmp(argv[1], "--forkavlauncher") == 0)
    4969             :     {
    4970             :         /* Restore basic shared memory pointers */
    4971             :         InitShmemAccess(UsedShmemSegAddr);
    4972             : 
    4973             :         /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
    4974             :         InitProcess();
    4975             : 
    4976             :         /* Attach process to shared data structures */
    4977             :         CreateSharedMemoryAndSemaphores(0);
    4978             : 
    4979             :         AutoVacLauncherMain(argc - 2, argv + 2);    /* does not return */
    4980             :     }
    4981             :     if (strcmp(argv[1], "--forkavworker") == 0)
    4982             :     {
    4983             :         /* Restore basic shared memory pointers */
    4984             :         InitShmemAccess(UsedShmemSegAddr);
    4985             : 
    4986             :         /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
    4987             :         InitProcess();
    4988             : 
    4989             :         /* Attach process to shared data structures */
    4990             :         CreateSharedMemoryAndSemaphores(0);
    4991             : 
    4992             :         AutoVacWorkerMain(argc - 2, argv + 2);  /* does not return */
    4993             :     }
    4994             :     if (strncmp(argv[1], "--forkbgworker=", 15) == 0)
    4995             :     {
    4996             :         int         shmem_slot;
    4997             : 
    4998             :         /* do this as early as possible; in particular, before InitProcess() */
    4999             :         IsBackgroundWorker = true;
    5000             : 
    5001             :         /* Restore basic shared memory pointers */
    5002             :         InitShmemAccess(UsedShmemSegAddr);
    5003             : 
    5004             :         /* Need a PGPROC to run CreateSharedMemoryAndSemaphores */
    5005             :         InitProcess();
    5006             : 
    5007             :         /* Attach process to shared data structures */
    5008             :         CreateSharedMemoryAndSemaphores(0);
    5009             : 
    5010             :         /* Fetch MyBgworkerEntry from shared memory */
    5011             :         shmem_slot = atoi(argv[1] + 15);
    5012             :         MyBgworkerEntry = BackgroundWorkerEntry(shmem_slot);
    5013             : 
    5014             :         StartBackgroundWorker();
    5015             :     }
    5016             :     if (strcmp(argv[1], "--forkarch") == 0)
    5017             :     {
    5018             :         /* Do not want to attach to shared memory */
    5019             : 
    5020             :         PgArchiverMain(argc, argv); /* does not return */
    5021             :     }
    5022             :     if (strcmp(argv[1], "--forkcol") == 0)
    5023             :     {
    5024             :         /* Do not want to attach to shared memory */
    5025             : 
    5026             :         PgstatCollectorMain(argc, argv);    /* does not return */
    5027             :     }
    5028             :     if (strcmp(argv[1], "--forklog") == 0)
    5029             :     {
    5030             :         /* Do not want to attach to shared memory */
    5031             : 
    5032             :         SysLoggerMain(argc, argv);  /* does not return */
    5033             :     }
    5034             : 
    5035             :     abort();                    /* shouldn't get here */
    5036             : }
    5037             : #endif                          /* EXEC_BACKEND */
    5038             : 
    5039             : 
    5040             : /*
    5041             :  * ExitPostmaster -- cleanup
    5042             :  *
    5043             :  * Do NOT call exit() directly --- always go through here!
    5044             :  */
    5045             : static void
    5046         568 : ExitPostmaster(int status)
    5047             : {
    5048             : #ifdef HAVE_PTHREAD_IS_THREADED_NP
    5049             : 
    5050             :     /*
    5051             :      * There is no known cause for a postmaster to become multithreaded after
    5052             :      * startup.  Recheck to account for the possibility of unknown causes.
    5053             :      * This message uses LOG level, because an unclean shutdown at this point
    5054             :      * would usually not look much different from a clean shutdown.
    5055             :      */
    5056             :     if (pthread_is_threaded_np() != 0)
    5057             :         ereport(LOG,
    5058             :                 (errcode(ERRCODE_INTERNAL_ERROR),
    5059             :                  errmsg_internal("postmaster became multithreaded"),
    5060             :                  errdetail("Please report this to <pgsql-bugs@lists.postgresql.org>.")));
    5061             : #endif
    5062             : 
    5063             :     /* should cleanup shared memory and kill all backends */
    5064             : 
    5065             :     /*
    5066             :      * Not sure of the semantics here.  When the Postmaster dies, should the
    5067             :      * backends all be killed? probably not.
    5068             :      *
    5069             :      * MUST     -- vadim 05-10-1999
    5070             :      */
    5071             : 
    5072         568 :     proc_exit(status);
    5073             : }
    5074             : 
    5075             : /*
    5076             :  * sigusr1_handler - handle signal conditions from child processes
    5077             :  */
    5078             : static void
    5079        1850 : sigusr1_handler(SIGNAL_ARGS)
    5080             : {
    5081        1850 :     int         save_errno = errno;
    5082             : 
    5083        1850 :     PG_SETMASK(&BlockSig);
    5084             : 
    5085             :     /* Process background worker state change. */
    5086        1850 :     if (CheckPostmasterSignal(PMSIGNAL_BACKGROUND_WORKER_CHANGE))
    5087             :     {
    5088         870 :         BackgroundWorkerStateChange();
    5089         870 :         StartWorkerNeeded = true;
    5090             :     }
    5091             : 
    5092             :     /*
    5093             :      * RECOVERY_STARTED and BEGIN_HOT_STANDBY signals are ignored in
    5094             :      * unexpected states. If the startup process quickly starts up, completes
    5095             :      * recovery, exits, we might process the death of the startup process
    5096             :      * first. We don't want to go back to recovery in that case.
    5097             :      */
    5098        1970 :     if (CheckPostmasterSignal(PMSIGNAL_RECOVERY_STARTED) &&
    5099         240 :         pmState == PM_STARTUP && Shutdown == NoShutdown)
    5100             :     {
    5101             :         /* WAL redo has started. We're out of reinitialization. */
    5102         120 :         FatalError = false;
    5103             :         Assert(AbortStartTime == 0);
    5104             : 
    5105             :         /*
    5106             :          * Crank up the background tasks.  It doesn't matter if this fails,
    5107             :          * we'll just try again later.
    5108             :          */
    5109             :         Assert(CheckpointerPID == 0);
    5110         120 :         CheckpointerPID = StartCheckpointer();
    5111             :         Assert(BgWriterPID == 0);
    5112         120 :         BgWriterPID = StartBackgroundWriter();
    5113             : 
    5114             :         /*
    5115             :          * Start the archiver if we're responsible for (re-)archiving received
    5116             :          * files.
    5117             :          */
    5118             :         Assert(PgArchPID == 0);
    5119         120 :         if (XLogArchivingAlways())
    5120           0 :             PgArchPID = pgarch_start();
    5121             : 
    5122             :         /*
    5123             :          * If we aren't planning to enter hot standby mode later, treat
    5124             :          * RECOVERY_STARTED as meaning we're out of startup, and report status
    5125             :          * accordingly.
    5126             :          */
    5127         120 :         if (!EnableHotStandby)
    5128             :         {
    5129           0 :             AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_STANDBY);
    5130             : #ifdef USE_SYSTEMD
    5131             :             sd_notify(0, "READY=1");
    5132             : #endif
    5133             :         }
    5134             : 
    5135         120 :         pmState = PM_RECOVERY;
    5136             :     }
    5137        1970 :     if (CheckPostmasterSignal(PMSIGNAL_BEGIN_HOT_STANDBY) &&
    5138         240 :         pmState == PM_RECOVERY && Shutdown == NoShutdown)
    5139             :     {
    5140             :         /*
    5141             :          * Likewise, start other special children as needed.
    5142             :          */
    5143             :         Assert(PgStatPID == 0);
    5144         120 :         PgStatPID = pgstat_start();
    5145             : 
    5146         120 :         ereport(LOG,
    5147             :                 (errmsg("database system is ready to accept read only connections")));
    5148             : 
    5149             :         /* Report status */
    5150         120 :         AddToDataDirLockFile(LOCK_FILE_LINE_PM_STATUS, PM_STATUS_READY);
    5151             : #ifdef USE_SYSTEMD
    5152             :         sd_notify(0, "READY=1");
    5153             : #endif
    5154             : 
    5155         120 :         pmState = PM_HOT_STANDBY;
    5156             :         /* Some workers may be scheduled to start now */
    5157         120 :         StartWorkerNeeded = true;
    5158             :     }
    5159             : 
    5160        1850 :     if (StartWorkerNeeded || HaveCrashedWorker)
    5161         998 :         maybe_start_bgworkers();
    5162             : 
    5163        1876 :     if (CheckPostmasterSignal(PMSIGNAL_WAKEN_ARCHIVER) &&
    5164          26 :         PgArchPID != 0)
    5165             :     {
    5166             :         /*
    5167             :          * Send SIGUSR1 to archiver process, to wake it up and begin archiving
    5168             :          * next WAL file.
    5169             :          */
    5170          22 :         signal_child(PgArchPID, SIGUSR1);
    5171             :     }
    5172             : 
    5173             :     /* Tell syslogger to rotate logfile if requested */
    5174        1850 :     if (SysLoggerPID != 0)
    5175             :     {
    5176           2 :         if (CheckLogrotateSignal())
    5177             :         {
    5178           2 :             signal_child(SysLoggerPID, SIGUSR1);
    5179           2 :             RemoveLogrotateSignalFiles();
    5180             :         }
    5181           0 :         else if (CheckPostmasterSignal(PMSIGNAL_ROTATE_LOGFILE))
    5182             :         {
    5183           0 :             signal_child(SysLoggerPID, SIGUSR1);
    5184             :         }
    5185             :     }
    5186             : 
    5187        1856 :     if (CheckPostmasterSignal(PMSIGNAL_START_AUTOVAC_LAUNCHER) &&
    5188           6 :         Shutdown == NoShutdown)
    5189             :     {
    5190             :         /*
    5191             :          * Start one iteration of the autovacuum daemon, even if autovacuuming
    5192             :          * is nominally not enabled.  This is so we can have an active defense
    5193             :          * against transaction ID wraparound.  We set a flag for the main loop
    5194             :          * to do it rather than trying to do it here --- this is because the
    5195             :          * autovac process itself may send the signal, and we want to handle
    5196             :          * that by launching another iteration as soon as the current one
    5197             :          * completes.
    5198             :          */
    5199           6 :         start_autovac_launcher = true;
    5200             :     }
    5201             : 
    5202        1910 :     if (CheckPostmasterSignal(PMSIGNAL_START_AUTOVAC_WORKER) &&
    5203          60 :         Shutdown == NoShutdown)
    5204             :     {
    5205             :         /* The autovacuum launcher wants us to start a worker process. */
    5206          60 :         StartAutovacuumWorker();
    5207             :     }
    5208             : 
    5209        1850 :     if (CheckPostmasterSignal(PMSIGNAL_START_WALRECEIVER))
    5210             :     {
    5211             :         /* Startup Process wants us to start the walreceiver process. */
    5212             :         /* Start immediately if possible, else remember request for later. */
    5213         208 :         WalReceiverRequested = true;
    5214         208 :         MaybeStartWalReceiver();
    5215             :     }
    5216             : 
    5217             :     /*
    5218             :      * Try to advance postmaster's state machine, if a child requests it.
    5219             :      *
    5220             :      * Be careful about the order of this action relative to sigusr1_handler's
    5221             :      * other actions.  Generally, this should be after other actions, in case
    5222             :      * they have effects PostmasterStateMachine would need to know about.
    5223             :      * However, we should do it before the CheckPromoteSignal step, which
    5224             :      * cannot have any (immediate) effect on the state machine, but does
    5225             :      * depend on what state we're in now.
    5226             :      */
    5227        1850 :     if (CheckPostmasterSignal(PMSIGNAL_ADVANCE_STATE_MACHINE))
    5228             :     {
    5229         508 :         PostmasterStateMachine();
    5230             :     }
    5231             : 
    5232        2250 :     if (StartupPID != 0 &&
    5233        1176 :         (pmState == PM_STARTUP || pmState == PM_RECOVERY ||
    5234         782 :          pmState == PM_HOT_STANDBY || pmState == PM_WAIT_READONLY) &&
    5235         396 :         CheckPromoteSignal())
    5236             :     {
    5237             :         /* Tell startup process to finish recovery */
    5238          46 :         signal_child(StartupPID, SIGUSR2);
    5239             :     }
    5240             : 
    5241        1850 :     PG_SETMASK(&UnBlockSig);
    5242             : 
    5243        1850 :     errno = save_errno;
    5244        1850 : }
    5245             : 
    5246             : /*
    5247             :  * SIGTERM or SIGQUIT while processing startup packet.
    5248             :  * Clean up and exit(1).
    5249             :  *
    5250             :  * XXX: possible future improvement: try to send a message indicating
    5251             :  * why we are disconnecting.  Problem is to be sure we don't block while
    5252             :  * doing so, nor mess up SSL initialization.  In practice, if the client
    5253             :  * has wedged here, it probably couldn't do anything with the message anyway.
    5254             :  */
    5255             : static void
    5256           2 : startup_die(SIGNAL_ARGS)
    5257             : {
    5258           2 :     proc_exit(1);
    5259             : }
    5260             : 
    5261             : /*
    5262             :  * Dummy signal handler
    5263             :  *
    5264             :  * We use this for signals that we don't actually use in the postmaster,
    5265             :  * but we do use in backends.  If we were to SIG_IGN such signals in the
    5266             :  * postmaster, then a newly started backend might drop a signal that arrives
    5267             :  * before it's able to reconfigure its signal processing.  (See notes in
    5268             :  * tcop/postgres.c.)
    5269             :  */
    5270             : static void
    5271           0 : dummy_handler(SIGNAL_ARGS)
    5272             : {
    5273           0 : }
    5274             : 
    5275             : /*
    5276             :  * Timeout while processing startup packet.
    5277             :  * As for startup_die(), we clean up and exit(1).
    5278             :  */
    5279             : static void
    5280           0 : StartupPacketTimeoutHandler(void)
    5281             : {
    5282           0 :     proc_exit(1);
    5283             : }
    5284             : 
    5285             : 
    5286             : /*
    5287             :  * Generate a random cancel key.
    5288             :  */
    5289             : static bool
    5290        9210 : RandomCancelKey(int32 *cancel_key)
    5291             : {
    5292        9210 :     return pg_strong_random(cancel_key, sizeof(int32));
    5293             : }
    5294             : 
    5295             : /*
    5296             :  * Count up number of child processes of specified types (dead_end children
    5297             :  * are always excluded).
    5298             :  */
    5299             : static int
    5300       10032 : CountChildren(int target)
    5301             : {
    5302             :     dlist_iter  iter;
    5303       10032 :     int         cnt = 0;
    5304             : 
    5305       31498 :     dlist_foreach(iter, &BackendList)
    5306             :     {
    5307       21466 :         Backend    *bp = dlist_container(Backend, elem, iter.cur);
    5308             : 
    5309       21466 :         if (bp->dead_end)
    5310           0 :             continue;
    5311             : 
    5312             :         /*
    5313             :          * Since target == BACKEND_TYPE_ALL is the most common case, we test
    5314             :          * it first and avoid touching shared memory for every child.
    5315             :          */
    5316       21466 :         if (target != BACKEND_TYPE_ALL)
    5317             :         {
    5318             :             /*
    5319             :              * Assign bkend_type for any recently announced WAL Sender
    5320             :              * processes.
    5321             :              */
    5322        2924 :             if (bp->bkend_type == BACKEND_TYPE_NORMAL &&
    5323         640 :                 IsPostmasterChildWalSender(bp->child_slot))
    5324          42 :                 bp->bkend_type = BACKEND_TYPE_WALSND;
    5325             : 
    5326        2284 :             if (!(target & bp->bkend_type))
    5327         274 :                 continue;
    5328             :         }
    5329             : 
    5330       21192 :         cnt++;
    5331             :     }
    5332       10032 :     return cnt;
    5333             : }
    5334             : 
    5335             : 
    5336             : /*
    5337             :  * StartChildProcess -- start an auxiliary process for the postmaster
    5338             :  *
    5339             :  * "type" determines what kind of child will be started.  All child types
    5340             :  * initially go to AuxiliaryProcessMain, which will handle common setup.
    5341             :  *
    5342             :  * Return value of StartChildProcess is subprocess' PID, or 0 if failed
    5343             :  * to start subprocess.
    5344             :  */
    5345             : static pid_t
    5346        2430 : StartChildProcess(AuxProcType type)
    5347             : {
    5348             :     pid_t       pid;
    5349             :     char       *av[10];
    5350        2430 :     int         ac = 0;
    5351             :     char        typebuf[32];
    5352             : 
    5353             :     /*
    5354             :      * Set up command-line arguments for subprocess
    5355             :      */
    5356        2430 :     av[ac++] = "postgres";
    5357             : 
    5358             : #ifdef EXEC_BACKEND
    5359             :     av[ac++] = "--forkboot";
    5360             :     av[ac++] = NULL;            /* filled in by postmaster_forkexec */
    5361             : #endif
    5362             : 
    5363        2430 :     snprintf(typebuf, sizeof(typebuf), "-x%d", type);
    5364        2430 :     av[ac++] = typebuf;
    5365             : 
    5366        2430 :     av[ac] = NULL;
    5367             :     Assert(ac < lengthof(av));
    5368             : 
    5369             : #ifdef EXEC_BACKEND
    5370             :     pid = postmaster_forkexec(ac, av);
    5371             : #else                           /* !EXEC_BACKEND */
    5372        2430 :     pid = fork_process();
    5373             : 
    5374        4252 :     if (pid == 0)               /* child */
    5375             :     {
    5376        1822 :         InitPostmasterChild();
    5377             : 
    5378             :         /* Close the postmaster's sockets */
    5379        1822 :         ClosePostmasterPorts(false);
    5380             : 
    5381             :         /* Release postmaster's working memory context */
    5382        1822 :         MemoryContextSwitchTo(TopMemoryContext);
    5383        1822 :         MemoryContextDelete(PostmasterContext);
    5384        1822 :         PostmasterContext = NULL;
    5385             : 
    5386        1822 :         AuxiliaryProcessMain(ac, av);
    5387             :         ExitPostmaster(0);
    5388             :     }
    5389             : #endif                          /* EXEC_BACKEND */
    5390             : 
    5391        2430 :     if (pid < 0)
    5392             :     {
    5393             :         /* in parent, fork failed */
    5394           0 :         int         save_errno = errno;
    5395             : 
    5396           0 :         errno = save_errno;
    5397           0 :         switch (type)
    5398             :         {
    5399             :             case StartupProcess:
    5400           0 :                 ereport(LOG,
    5401             :                         (errmsg("could not fork startup process: %m")));
    5402           0 :                 break;
    5403             :             case BgWriterProcess:
    5404           0 :                 ereport(LOG,
    5405             :                         (errmsg("could not fork background writer process: %m")));
    5406           0 :                 break;
    5407             :             case CheckpointerProcess:
    5408           0 :                 ereport(LOG,
    5409             :                         (errmsg("could not fork checkpointer process: %m")));
    5410           0 :                 break;
    5411             :             case WalWriterProcess:
    5412           0 :                 ereport(LOG,
    5413             :                         (errmsg("could not fork WAL writer process: %m")));
    5414           0 :                 break;
    5415             :             case WalReceiverProcess:
    5416           0 :                 ereport(LOG,
    5417             :                         (errmsg("could not fork WAL receiver process: %m")));
    5418           0 :                 break;
    5419             :             default:
    5420           0 :                 ereport(LOG,
    5421             :                         (errmsg("could not fork process: %m")));
    5422           0 :                 break;
    5423             :         }
    5424             : 
    5425             :         /*
    5426             :          * fork failure is fatal during startup, but there's no need to choke
    5427             :          * immediately if starting other child types fails.
    5428             :          */
    5429           0 :         if (type == StartupProcess)
    5430           0 :             ExitPostmaster(1);
    5431           0 :         return 0;
    5432             :     }
    5433             : 
    5434             :     /*
    5435             :      * in parent, successful fork
    5436             :      */
    5437        2430 :     return pid;
    5438             : }
    5439             : 
    5440             : /*
    5441             :  * StartAutovacuumWorker
    5442             :  *      Start an autovac worker process.
    5443             :  *
    5444             :  * This function is here because it enters the resulting PID into the
    5445             :  * postmaster's private backends list.
    5446             :  *
    5447             :  * NB -- this code very roughly matches BackendStartup.
    5448             :  */
    5449             : static void
    5450          60 : StartAutovacuumWorker(void)
    5451             : {
    5452             :     Backend    *bn;
    5453             : 
    5454             :     /*
    5455             :      * If not in condition to run a process, don't try, but handle it like a
    5456             :      * fork failure.  This does not normally happen, since the signal is only
    5457             :      * supposed to be sent by autovacuum launcher when it's OK to do it, but
    5458             :      * we have to check to avoid race-condition problems during DB state
    5459             :      * changes.
    5460             :      */
    5461          60 :     if (canAcceptConnections() == CAC_OK)
    5462             :     {
    5463             :         /*
    5464             :          * Compute the cancel key that will be assigned to this session. We
    5465             :          * probably don't need cancel keys for autovac workers, but we'd
    5466             :          * better have something random in the field to prevent unfriendly
    5467             :          * people from sending cancels to them.
    5468             :          */
    5469          60 :         if (!RandomCancelKey(&MyCancelKey))
    5470             :         {
    5471           0 :             ereport(LOG,
    5472             :                     (errcode(ERRCODE_INTERNAL_ERROR),
    5473             :                      errmsg("could not generate random cancel key")));
    5474           0 :             return;
    5475             :         }
    5476             : 
    5477          60 :         bn = (Backend *) malloc(sizeof(Backend));
    5478          60 :         if (bn)
    5479             :         {
    5480          60 :             bn->cancel_key = MyCancelKey;
    5481             : 
    5482             :             /* Autovac workers are not dead_end and need a child slot */
    5483          60 :             bn->dead_end = false;
    5484          60 :             bn->child_slot = MyPMChildSlot = AssignPostmasterChildSlot();
    5485          60 :             bn->bgworker_notify = false;
    5486             : 
    5487          60 :             bn->pid = StartAutoVacWorker();
    5488          60 :             if (bn->pid > 0)
    5489             :             {
    5490          60 :                 bn->bkend_type = BACKEND_TYPE_AUTOVAC;
    5491          60 :                 dlist_push_head(&BackendList, &bn->elem);
    5492             : #ifdef EXEC_BACKEND
    5493             :                 ShmemBackendArrayAdd(bn);
    5494             : #endif
    5495             :                 /* all OK */
    5496          60 :                 return;
    5497             :             }
    5498             : 
    5499             :             /*
    5500             :              * fork failed, fall through to report -- actual error message was
    5501             :              * logged by StartAutoVacWorker
    5502             :              */
    5503           0 :             (void) ReleasePostmasterChildSlot(bn->child_slot);
    5504           0 :             free(bn);
    5505             :         }
    5506             :         else
    5507           0 :             ereport(LOG,
    5508             :                     (errcode(ERRCODE_OUT_OF_MEMORY),
    5509             :                      errmsg("out of memory")));
    5510             :     }
    5511             : 
    5512             :     /*
    5513             :      * Report the failure to the launcher, if it's running.  (If it's not, we
    5514             :      * might not even be connected to shared memory, so don't try to call
    5515             :      * AutoVacWorkerFailed.)  Note that we also need to signal it so that it
    5516             :      * responds to the condition, but we don't do that here, instead waiting
    5517             :      * for ServerLoop to do it.  This way we avoid a ping-pong signalling in
    5518             :      * quick succession between the autovac launcher and postmaster in case
    5519             :      * things get ugly.
    5520             :      */
    5521           0 :     if (AutoVacPID != 0)
    5522             :     {
    5523           0 :         AutoVacWorkerFailed();
    5524           0 :         avlauncher_needs_signal = true;
    5525             :     }
    5526             : }
    5527             : 
    5528             : /*
    5529             :  * MaybeStartWalReceiver
    5530             :  *      Start the WAL receiver process, if not running and our state allows.
    5531             :  *
    5532             :  * Note: if WalReceiverPID is already nonzero, it might seem that we should
    5533             :  * clear WalReceiverRequested.  However, there's a race condition if the
    5534             :  * walreceiver terminates and the startup process immediately requests a new
    5535             :  * one: it's quite possible to get the signal for the request before reaping
    5536             :  * the dead walreceiver process.  Better to risk launching an extra
    5537             :  * walreceiver than to miss launching one we need.  (The walreceiver code
    5538             :  * has logic to recognize that it should go away if not needed.)
    5539             :  */
    5540             : static void
    5541         360 : MaybeStartWalReceiver(void)
    5542             : {
    5543         584 :     if (WalReceiverPID == 0 &&
    5544         666 :         (pmState == PM_STARTUP || pmState == PM_RECOVERY ||
    5545         442 :          pmState == PM_HOT_STANDBY || pmState == PM_WAIT_READONLY) &&
    5546         204 :         Shutdown == NoShutdown)
    5547             :     {
    5548         204 :         WalReceiverPID = StartWalReceiver();
    5549         204 :         if (WalReceiverPID != 0)
    5550         204 :             WalReceiverRequested = false;
    5551             :         /* else leave the flag set, so we'll try again later */
    5552             :     }
    5553         360 : }
    5554             : 
    5555             : 
    5556             : /*
    5557             :  * Create the opts file
    5558             :  */
    5559             : static bool
    5560         572 : CreateOptsFile(int argc, char *argv[], char *fullprogname)
    5561             : {
    5562             :     FILE       *fp;
    5563             :     int         i;
    5564             : 
    5565             : #define OPTS_FILE   "postmaster.opts"
    5566             : 
    5567         572 :     if ((fp = fopen(OPTS_FILE, "w")) == NULL)
    5568             :     {
    5569           0 :         elog(LOG, "could not create file \"%s\": %m", OPTS_FILE);
    5570           0 :         return false;
    5571             :     }
    5572             : 
    5573         572 :     fprintf(fp, "%s", fullprogname);
    5574        2876 :     for (i = 1; i < argc; i++)
    5575        2304 :         fprintf(fp, " \"%s\"", argv[i]);
    5576         572 :     fputs("\n", fp);
    5577             : 
    5578         572 :     if (fclose(fp))
    5579             :     {
    5580           0 :         elog(LOG, "could not write file \"%s\": %m", OPTS_FILE);
    5581           0 :         return false;
    5582             :     }
    5583             : 
    5584         572 :     return true;
    5585             : }
    5586             : 
    5587             : 
    5588             : /*
    5589             :  * MaxLivePostmasterChildren
    5590             :  *
    5591             :  * This reports the number of entries needed in per-child-process arrays
    5592             :  * (the PMChildFlags array, and if EXEC_BACKEND the ShmemBackendArray).
    5593             :  * These arrays include regular backends, autovac workers, walsenders
    5594             :  * and background workers, but not special children nor dead_end children.
    5595             :  * This allows the arrays to have a fixed maximum size, to wit the same
    5596             :  * too-many-children limit enforced by canAcceptConnections().  The exact value
    5597             :  * isn't too critical as long as it's more than MaxBackends.
    5598             :  */
    5599             : int
    5600       14246 : MaxLivePostmasterChildren(void)
    5601             : {
    5602       28492 :     return 2 * (MaxConnections + autovacuum_max_workers + 1 +
    5603       14246 :                 max_wal_senders + max_worker_processes);
    5604             : }
    5605             : 
    5606             : /*
    5607             :  * Connect background worker to a database.
    5608             :  */
    5609             : void
    5610         364 : BackgroundWorkerInitializeConnection(const char *dbname, const char *username, uint32 flags)
    5611             : {
    5612         364 :     BackgroundWorker *worker = MyBgworkerEntry;
    5613             : 
    5614             :     /* XXX is this the right errcode? */
    5615         364 :     if (!(worker->bgw_flags & BGWORKER_BACKEND_DATABASE_CONNECTION))
    5616           0 :         ereport(FATAL,
    5617             :                 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
    5618             :                  errmsg("database connection requirement not indicated during registration")));
    5619             : 
    5620         364 :     InitPostgres(dbname, InvalidOid, username, InvalidOid, NULL, (flags & BGWORKER_BYPASS_ALLOWCONN) != 0);
    5621             : 
    5622             :     /* it had better not gotten out of "init" mode yet */
    5623         360 :     if (!IsInitProcessingMode())
    5624           0 :         ereport(ERROR,
    5625             :                 (errmsg("invalid processing mode in background worker")));
    5626         360 :     SetProcessingMode(NormalProcessing);
    5627         360 : }
    5628             : 
    5629             : /*
    5630             :  * Connect background worker to a database using OIDs.
    5631             :  */
    5632             : void
    5633        1762 : BackgroundWorkerInitializeConnectionByOid(Oid dboid, Oid useroid, uint32 flags)
    5634             : {
    5635        1762 :     BackgroundWorker *worker = MyBgworkerEntry;
    5636             : 
    5637             :     /* XXX is this the right errcode? */
    5638        1762 :     if (!(worker->bgw_flags & BGWORKER_BACKEND_DATABASE_CONNECTION))
    5639           0 :         ereport(FATAL,
    5640             :                 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
    5641             :                  errmsg("database connection requirement not indicated during registration")));
    5642             : 
    5643        1762 :     InitPostgres(NULL, dboid, NULL, useroid, NULL, (flags & BGWORKER_BYPASS_ALLOWCONN) != 0);
    5644             : 
    5645             :     /* it had better not gotten out of "init" mode yet */
    5646        1762 :     if (!IsInitProcessingMode())
    5647           0 :         ereport(ERROR,
    5648             :                 (errmsg("invalid processing mode in background worker")));
    5649        1762 :     SetProcessingMode(NormalProcessing);
    5650        1762 : }
    5651             : 
    5652             : /*
    5653             :  * Block/unblock signals in a background worker
    5654             :  */
    5655             : void
    5656           0 : BackgroundWorkerBlockSignals(void)
    5657             : {
    5658           0 :     PG_SETMASK(&BlockSig);
    5659           0 : }
    5660             : 
    5661             : void
    5662        2140 : BackgroundWorkerUnblockSignals(void)
    5663             : {
    5664        2140 :     PG_SETMASK(&UnBlockSig);
    5665        2140 : }
    5666             : 
    5667             : #ifdef EXEC_BACKEND
    5668             : static pid_t
    5669             : bgworker_forkexec(int shmem_slot)
    5670             : {
    5671             :     char       *av[10];
    5672             :     int         ac = 0;
    5673             :     char        forkav[MAXPGPATH];
    5674             : 
    5675             :     snprintf(forkav, MAXPGPATH, "--forkbgworker=%d", shmem_slot);
    5676             : 
    5677             :     av[ac++] = "postgres";
    5678             :     av[ac++] = forkav;
    5679             :     av[ac++] = NULL;            /* filled in by postmaster_forkexec */
    5680             :     av[ac] = NULL;
    5681             : 
    5682             :     Assert(ac < lengthof(av));
    5683             : 
    5684             :     return postmaster_forkexec(ac, av);
    5685             : }
    5686             : #endif
    5687             : 
    5688             : /*
    5689             :  * Start a new bgworker.
    5690             :  * Starting time conditions must have been checked already.
    5691             :  *
    5692             :  * Returns true on success, false on failure.
    5693             :  * In either case, update the RegisteredBgWorker's state appropriately.
    5694             :  *
    5695             :  * This code is heavily based on autovacuum.c, q.v.
    5696             :  */
    5697             : static bool
    5698        2280 : do_start_bgworker(RegisteredBgWorker *rw)
    5699             : {
    5700             :     pid_t       worker_pid;
    5701             : 
    5702             :     Assert(rw->rw_pid == 0);
    5703             : 
    5704             :     /*
    5705             :      * Allocate and assign the Backend element.  Note we must do this before
    5706             :      * forking, so that we can handle out of memory properly.
    5707             :      *
    5708             :      * Treat failure as though the worker had crashed.  That way, the
    5709             :      * postmaster will wait a bit before attempting to start it again; if it
    5710             :      * tried again right away, most likely it'd find itself repeating the
    5711             :      * out-of-memory or fork failure condition.
    5712             :      */
    5713        2280 :     if (!assign_backendlist_entry(rw))
    5714             :     {
    5715           0 :         rw->rw_crashed_at = GetCurrentTimestamp();
    5716           0 :         return false;
    5717             :     }
    5718             : 
    5719        2280 :     ereport(DEBUG1,
    5720             :             (errmsg("starting background worker process \"%s\"",
    5721             :                     rw->rw_worker.bgw_name)));
    5722             : 
    5723             : #ifdef EXEC_BACKEND
    5724             :     switch ((worker_pid = bgworker_forkexec(rw->rw_shmem_slot)))
    5725             : #else
    5726        2280 :     switch ((worker_pid = fork_process()))
    5727             : #endif
    5728             :     {
    5729             :         case -1:
    5730             :             /* in postmaster, fork failed ... */
    5731           0 :             ereport(LOG,
    5732             :                     (errmsg("could not fork worker process: %m")));
    5733             :             /* undo what assign_backendlist_entry did */
    5734           0 :             ReleasePostmasterChildSlot(rw->rw_child_slot);
    5735           0 :             rw->rw_child_slot = 0;
    5736           0 :             free(rw->rw_backend);
    5737           0 :             rw->rw_backend = NULL;
    5738             :             /* mark entry as crashed, so we'll try again later */
    5739           0 :             rw->rw_crashed_at = GetCurrentTimestamp();
    5740           0 :             break;
    5741             : 
    5742             : #ifndef EXEC_BACKEND
    5743             :         case 0:
    5744             :             /* in postmaster child ... */
    5745        2140 :             InitPostmasterChild();
    5746             : 
    5747             :             /* Close the postmaster's sockets */
    5748        2140 :             ClosePostmasterPorts(false);
    5749             : 
    5750             :             /*
    5751             :              * Before blowing away PostmasterContext, save this bgworker's
    5752             :              * data where it can find it.
    5753             :              */
    5754        2140 :             MyBgworkerEntry = (BackgroundWorker *)
    5755        2140 :                 MemoryContextAlloc(TopMemoryContext, sizeof(BackgroundWorker));
    5756        2140 :             memcpy(MyBgworkerEntry, &rw->rw_worker, sizeof(BackgroundWorker));
    5757             : 
    5758             :             /* Release postmaster's working memory context */
    5759        2140 :             MemoryContextSwitchTo(TopMemoryContext);
    5760        2140 :             MemoryContextDelete(PostmasterContext);
    5761        2140 :             PostmasterContext = NULL;
    5762             : 
    5763        2140 :             StartBackgroundWorker();
    5764             : 
    5765             :             exit(1);            /* should not get here */
    5766             :             break;
    5767             : #endif
    5768             :         default:
    5769             :             /* in postmaster, fork successful ... */
    5770        2278 :             rw->rw_pid = worker_pid;
    5771        2278 :             rw->rw_backend->pid = rw->rw_pid;
    5772        2278 :             ReportBackgroundWorkerPID(rw);
    5773             :             /* add new worker to lists of backends */
    5774        2278 :             dlist_push_head(&BackendList, &rw->rw_backend->elem);
    5775             : #ifdef EXEC_BACKEND
    5776             :             ShmemBackendArrayAdd(rw->rw_backend);
    5777             : #endif
    5778        2278 :             return true;
    5779             :     }
    5780             : 
    5781           0 :     return false;
    5782             : }
    5783             : 
    5784             : /*
    5785             :  * Does the current postmaster state require starting a worker with the
    5786             :  * specified start_time?
    5787             :  */
    5788             : static bool
    5789        2976 : bgworker_should_start_now(BgWorkerStartTime start_time)
    5790             : {
    5791        2976 :     switch (pmState)
    5792             :     {
    5793             :         case PM_NO_CHILDREN:
    5794             :         case PM_WAIT_DEAD_END:
    5795             :         case PM_SHUTDOWN_2:
    5796             :         case PM_SHUTDOWN:
    5797             :         case PM_WAIT_BACKENDS:
    5798             :         case PM_WAIT_READONLY:
    5799             :         case PM_WAIT_BACKUP:
    5800           0 :             break;
    5801             : 
    5802             :         case PM_RUN:
    5803        2280 :             if (start_time == BgWorkerStart_RecoveryFinished)
    5804         624 :                 return true;
    5805             :             /* fall through */
    5806             : 
    5807             :         case PM_HOT_STANDBY:
    5808        1776 :             if (start_time == BgWorkerStart_ConsistentState)
    5809        1656 :                 return true;
    5810             :             /* fall through */
    5811             : 
    5812             :         case PM_RECOVERY:
    5813             :         case PM_STARTUP:
    5814             :         case PM_INIT:
    5815         696 :             if (start_time == BgWorkerStart_PostmasterStart)
    5816           0 :                 return true;
    5817             :             /* fall through */
    5818             : 
    5819             :     }
    5820             : 
    5821         696 :     return false;
    5822             : }
    5823             : 
    5824             : /*
    5825             :  * Allocate the Backend struct for a connected background worker, but don't
    5826             :  * add it to the list of backends just yet.
    5827             :  *
    5828             :  * On failure, return false without changing any worker state.
    5829             :  *
    5830             :  * Some info from the Backend is copied into the passed rw.
    5831             :  */
    5832             : static bool
    5833        2280 : assign_backendlist_entry(RegisteredBgWorker *rw)
    5834             : {
    5835             :     Backend    *bn;
    5836             : 
    5837             :     /*
    5838             :      * Compute the cancel key that will be assigned to this session. We
    5839             :      * probably don't need cancel keys for background workers, but we'd better
    5840             :      * have something random in the field to prevent unfriendly people from
    5841             :      * sending cancels to them.
    5842             :      */
    5843        2280 :     if (!RandomCancelKey(&MyCancelKey))
    5844             :     {
    5845           0 :         ereport(LOG,
    5846             :                 (errcode(ERRCODE_INTERNAL_ERROR),
    5847             :                  errmsg("could not generate random cancel key")));
    5848           0 :         return false;
    5849             :     }
    5850             : 
    5851        2280 :     bn = malloc(sizeof(Backend));
    5852        2280 :     if (bn == NULL)
    5853             :     {
    5854           0 :         ereport(LOG,
    5855             :                 (errcode(ERRCODE_OUT_OF_MEMORY),
    5856             :                  errmsg("out of memory")));
    5857           0 :         return false;
    5858             :     }
    5859             : 
    5860        2280 :     bn->cancel_key = MyCancelKey;
    5861        2280 :     bn->child_slot = MyPMChildSlot = AssignPostmasterChildSlot();
    5862        2280 :     bn->bkend_type = BACKEND_TYPE_BGWORKER;
    5863        2280 :     bn->dead_end = false;
    5864        2280 :     bn->bgworker_notify = false;
    5865             : 
    5866        2280 :     rw->rw_backend = bn;
    5867        2280 :     rw->rw_child_slot = bn->child_slot;
    5868             : 
    5869        2280 :     return true;
    5870             : }
    5871             : 
    5872             : /*
    5873             :  * If the time is right, start background worker(s).
    5874             :  *
    5875             :  * As a side effect, the bgworker control variables are set or reset
    5876             :  * depending on whether more workers may need to be started.
    5877             :  *
    5878             :  * We limit the number of workers started per call, to avoid consuming the
    5879             :  * postmaster's attention for too long when many such requests are pending.
    5880             :  * As long as StartWorkerNeeded is true, ServerLoop will not block and will
    5881             :  * call this function again after dealing with any other issues.
    5882             :  */
    5883             : static void
    5884        5138 : maybe_start_bgworkers(void)
    5885             : {
    5886             : #define MAX_BGWORKERS_TO_LAUNCH 100
    5887        5138 :     int         num_launched = 0;
    5888        5138 :     TimestampTz now = 0;
    5889             :     slist_mutable_iter iter;
    5890             : 
    5891             :     /*
    5892             :      * During crash recovery, we have no need to be called until the state
    5893             :      * transition out of recovery.
    5894             :      */
    5895        5138 :     if (FatalError)
    5896             :     {
    5897           4 :         StartWorkerNeeded = false;
    5898           4 :         HaveCrashedWorker = false;
    5899           8 :         return;
    5900             :     }
    5901             : 
    5902             :     /* Don't need to be called again unless we find a reason for it below */
    5903        5134 :     StartWorkerNeeded = false;
    5904        5134 :     HaveCrashedWorker = false;
    5905             : 
    5906       14078 :     slist_foreach_modify(iter, &BackgroundWorkerList)
    5907             :     {
    5908             :         RegisteredBgWorker *rw;
    5909             : 
    5910        8946 :         rw = slist_container(RegisteredBgWorker, rw_lnode, iter.cur);
    5911             : 
    5912             :         /* ignore if already running */
    5913        8946 :         if (rw->rw_pid != 0)
    5914        4462 :             continue;
    5915             : 
    5916             :         /* if marked for death, clean up and remove from list */
    5917        4484 :         if (rw->rw_terminate)
    5918             :         {
    5919           0 :             ForgetBackgroundWorker(&iter);
    5920           0 :             continue;
    5921             :         }
    5922             : 
    5923             :         /*
    5924             :          * If this worker has crashed previously, maybe it needs to be
    5925             :          * restarted (unless on registration it specified it doesn't want to
    5926             :          * be restarted at all).  Check how long ago did a crash last happen.
    5927             :          * If the last crash is too recent, don't start it right away; let it
    5928             :          * be restarted once enough time has passed.
    5929             :          */
    5930        4484 :         if (rw->rw_crashed_at != 0)
    5931             :         {
    5932        1508 :             if (rw->rw_worker.bgw_restart_time == BGW_NEVER_RESTART)
    5933             :             {
    5934             :                 int         notify_pid;
    5935             : 
    5936           0 :                 notify_pid = rw->rw_worker.bgw_notify_pid;
    5937             : 
    5938           0 :                 ForgetBackgroundWorker(&iter);
    5939             : 
    5940             :                 /* Report worker is gone now. */
    5941           0 :                 if (notify_pid != 0)
    5942           0 :                     kill(notify_pid, SIGUSR1);
    5943             : 
    5944           0 :                 continue;
    5945             :             }
    5946             : 
    5947             :             /* read system time only when needed */
    5948        1508 :             if (now == 0)
    5949        1508 :                 now = GetCurrentTimestamp();
    5950             : 
    5951        1508 :             if (!TimestampDifferenceExceeds(rw->rw_crashed_at, now,
    5952        1508 :                                             rw->rw_worker.bgw_restart_time * 1000))
    5953             :             {
    5954             :                 /* Set flag to remember that we have workers to start later */
    5955        1508 :                 HaveCrashedWorker = true;
    5956        1508 :                 continue;
    5957             :             }
    5958             :         }
    5959             : 
    5960        2976 :         if (bgworker_should_start_now(rw->rw_worker.bgw_start_time))
    5961             :         {
    5962             :             /* reset crash time before trying to start worker */
    5963        2280 :             rw->rw_crashed_at = 0;
    5964             : 
    5965             :             /*
    5966             :              * Try to start the worker.
    5967             :              *
    5968             :              * On failure, give up processing workers for now, but set
    5969             :              * StartWorkerNeeded so we'll come back here on the next iteration
    5970             :              * of ServerLoop to try again.  (We don't want to wait, because
    5971             :              * there might be additional ready-to-run workers.)  We could set
    5972             :              * HaveCrashedWorker as well, since this worker is now marked
    5973             :              * crashed, but there's no need because the next run of this
    5974             :              * function will do that.
    5975             :              */
    5976        2280 :             if (!do_start_bgworker(rw))
    5977             :             {
    5978           0 :                 StartWorkerNeeded = true;
    5979           0 :                 return;
    5980             :             }
    5981             : 
    5982             :             /*
    5983             :              * If we've launched as many workers as allowed, quit, but have
    5984             :              * ServerLoop call us again to look for additional ready-to-run
    5985             :              * workers.  There might not be any, but we'll find out the next
    5986             :              * time we run.
    5987             :              */
    5988        2278 :             if (++num_launched >= MAX_BGWORKERS_TO_LAUNCH)
    5989             :             {
    5990           0 :                 StartWorkerNeeded = true;
    5991           0 :                 return;
    5992             :             }
    5993             :         }
    5994             :     }
    5995             : }
    5996             : 
    5997             : /*
    5998             :  * When a backend asks to be notified about worker state changes, we
    5999             :  * set a flag in its backend entry.  The background worker machinery needs
    6000             :  * to know when such backends exit.
    6001             :  */
    6002             : bool
    6003        1778 : PostmasterMarkPIDForWorkerNotify(int pid)
    6004             : {
    6005             :     dlist_iter  iter;
    6006             :     Backend    *bp;
    6007             : 
    6008        2876 :     dlist_foreach(iter, &BackendList)
    6009             :     {
    6010        2876 :         bp = dlist_container(Backend, elem, iter.cur);
    6011        2876 :         if (bp->pid == pid)
    6012             :         {
    6013        1778 :             bp->bgworker_notify = true;
    6014        1778 :             return true;
    6015             :         }
    6016             :     }
    6017           0 :     return false;
    6018             : }
    6019             : 
    6020             : #ifdef EXEC_BACKEND
    6021             : 
    6022             : /*
    6023             :  * The following need to be available to the save/restore_backend_variables
    6024             :  * functions.  They are marked NON_EXEC_STATIC in their home modules.
    6025             :  */
    6026             : extern slock_t *ShmemLock;
    6027             : extern slock_t *ProcStructLock;
    6028             : extern PGPROC *AuxiliaryProcs;
    6029             : extern PMSignalData *PMSignalState;
    6030             : extern pgsocket pgStatSock;
    6031             : extern pg_time_t first_syslogger_file_time;
    6032             : 
    6033             : #ifndef WIN32
    6034             : #define write_inheritable_socket(dest, src, childpid) ((*(dest) = (src)), true)
    6035             : #define read_inheritable_socket(dest, src) (*(dest) = *(src))
    6036             : #else
    6037             : static bool write_duplicated_handle(HANDLE *dest, HANDLE src, HANDLE child);
    6038             : static bool write_inheritable_socket(InheritableSocket *dest, SOCKET src,
    6039             :                                      pid_t childPid);
    6040             : static void read_inheritable_socket(SOCKET *dest, InheritableSocket *src);
    6041             : #endif
    6042             : 
    6043             : 
    6044             : /* Save critical backend variables into the BackendParameters struct */
    6045             : #ifndef WIN32
    6046             : static bool
    6047             : save_backend_variables(BackendParameters *param, Port *port)
    6048             : #else
    6049             : static bool
    6050             : save_backend_variables(BackendParameters *param, Port *port,
    6051             :                        HANDLE childProcess, pid_t childPid)
    6052             : #endif
    6053             : {
    6054             :     memcpy(&param->port, port, sizeof(Port));
    6055             :     if (!write_inheritable_socket(&param->portsocket, port->sock, childPid))
    6056             :         return false;
    6057             : 
    6058             :     strlcpy(param->DataDir, DataDir, MAXPGPATH);
    6059             : 
    6060             :     memcpy(&param->ListenSocket, &ListenSocket, sizeof(ListenSocket));
    6061             : 
    6062             :     param->MyCancelKey = MyCancelKey;
    6063             :     param->MyPMChildSlot = MyPMChildSlot;
    6064             : 
    6065             : #ifdef WIN32
    6066             :     param->ShmemProtectiveRegion = ShmemProtectiveRegion;
    6067             : #endif
    6068             :     param->UsedShmemSegID = UsedShmemSegID;
    6069             :     param->UsedShmemSegAddr = UsedShmemSegAddr;
    6070             : 
    6071             :     param->ShmemLock = ShmemLock;
    6072             :     param->ShmemVariableCache = ShmemVariableCache;
    6073             :     param->ShmemBackendArray = ShmemBackendArray;
    6074             : 
    6075             : #ifndef HAVE_SPINLOCKS
    6076             :     param->SpinlockSemaArray = SpinlockSemaArray;
    6077             : #endif
    6078             :     param->NamedLWLockTrancheRequests = NamedLWLockTrancheRequests;
    6079             :     param->NamedLWLockTrancheArray = NamedLWLockTrancheArray;
    6080             :     param->MainLWLockArray = MainLWLockArray;
    6081             :     param->ProcStructLock = ProcStructLock;
    6082             :     param->ProcGlobal = ProcGlobal;
    6083             :     param->AuxiliaryProcs = AuxiliaryProcs;
    6084             :     param->PreparedXactProcs = PreparedXactProcs;
    6085             :     param->PMSignalState = PMSignalState;
    6086             :     if (!write_inheritable_socket(&param->pgStatSock, pgStatSock, childPid))
    6087             :         return false;
    6088             : 
    6089             :     param->PostmasterPid = PostmasterPid;
    6090             :     param->PgStartTime = PgStartTime;
    6091             :     param->PgReloadTime = PgReloadTime;
    6092             :     param->first_syslogger_file_time = first_syslogger_file_time;
    6093             : 
    6094             :     param->redirection_done = redirection_done;
    6095             :     param->IsBinaryUpgrade = IsBinaryUpgrade;
    6096             :     param->max_safe_fds = max_safe_fds;
    6097             : 
    6098             :     param->MaxBackends = MaxBackends;
    6099             : 
    6100             : #ifdef WIN32
    6101             :     param->PostmasterHandle = PostmasterHandle;
    6102             :     if (!write_duplicated_handle(&param->initial_signal_pipe,
    6103             :                                  pgwin32_create_signal_listener(childPid),
    6104             :                                  childProcess))
    6105             :         return false;
    6106             : #else
    6107             :     memcpy(&param->postmaster_alive_fds, &postmaster_alive_fds,
    6108             :            sizeof(postmaster_alive_fds));
    6109             : #endif
    6110             : 
    6111             :     memcpy(&param->syslogPipe, &syslogPipe, sizeof(syslogPipe));
    6112             : 
    6113             :     strlcpy(param->my_exec_path, my_exec_path, MAXPGPATH);
    6114             : 
    6115             :     strlcpy(param->pkglib_path, pkglib_path, MAXPGPATH);
    6116             : 
    6117             :     strlcpy(param->ExtraOptions, ExtraOptions, MAXPGPATH);
    6118             : 
    6119             :     return true;
    6120             : }
    6121             : 
    6122             : 
    6123             : #ifdef WIN32
    6124             : /*
    6125             :  * Duplicate a handle for usage in a child process, and write the child
    6126             :  * process instance of the handle to the parameter file.
    6127             :  */
    6128             : static bool
    6129             : write_duplicated_handle(HANDLE *dest, HANDLE src, HANDLE childProcess)
    6130             : {
    6131             :     HANDLE      hChild = INVALID_HANDLE_VALUE;
    6132             : 
    6133             :     if (!DuplicateHandle(GetCurrentProcess(),
    6134             :                          src,
    6135             :                          childProcess,
    6136             :                          &hChild,
    6137             :                          0,
    6138             :                          TRUE,
    6139             :                          DUPLICATE_CLOSE_SOURCE | DUPLICATE_SAME_ACCESS))
    6140             :     {
    6141             :         ereport(LOG,
    6142             :                 (errmsg_internal("could not duplicate handle to be written to backend parameter file: error code %lu",
    6143             :                                  GetLastError())));
    6144             :         return false;
    6145             :     }
    6146             : 
    6147             :     *dest = hChild;
    6148             :     return true;
    6149             : }
    6150             : 
    6151             : /*
    6152             :  * Duplicate a socket for usage in a child process, and write the resulting
    6153             :  * structure to the parameter file.
    6154             :  * This is required because a number of LSPs (Layered Service Providers) very
    6155             :  * common on Windows (antivirus, firewalls, download managers etc) break
    6156             :  * straight socket inheritance.
    6157             :  */
    6158             : static bool
    6159             : write_inheritable_socket(InheritableSocket *dest, SOCKET src, pid_t childpid)
    6160             : {
    6161             :     dest->origsocket = src;
    6162             :     if (src != 0 && src != PGINVALID_SOCKET)
    6163             :     {
    6164             :         /* Actual socket */
    6165             :         if (WSADuplicateSocket(src, childpid, &dest->wsainfo) != 0)
    6166             :         {
    6167             :             ereport(LOG,
    6168             :                     (errmsg("could not duplicate socket %d for use in backend: error code %d",
    6169             :                             (int) src, WSAGetLastError())));
    6170             :             return false;
    6171             :         }
    6172             :     }
    6173             :     return true;
    6174             : }
    6175             : 
    6176             : /*
    6177             :  * Read a duplicate socket structure back, and get the socket descriptor.
    6178             :  */
    6179             : static void
    6180             : read_inheritable_socket(SOCKET *dest, InheritableSocket *src)
    6181             : {
    6182             :     SOCKET      s;
    6183             : 
    6184             :     if (src->origsocket == PGINVALID_SOCKET || src->origsocket == 0)
    6185             :     {
    6186             :         /* Not a real socket! */
    6187             :         *dest = src->origsocket;
    6188             :     }
    6189             :     else
    6190             :     {
    6191             :         /* Actual socket, so create from structure */
    6192             :         s = WSASocket(FROM_PROTOCOL_INFO,
    6193             :                       FROM_PROTOCOL_INFO,
    6194             :                       FROM_PROTOCOL_INFO,
    6195             :                       &src->wsainfo,
    6196             :                       0,
    6197             :                       0);
    6198             :         if (s == INVALID_SOCKET)
    6199             :         {
    6200             :             write_stderr("could not create inherited socket: error code %d\n",
    6201             :                          WSAGetLastError());
    6202             :             exit(1);
    6203             :         }
    6204             :         *dest = s;
    6205             : 
    6206             :         /*
    6207             :          * To make sure we don't get two references to the same socket, close
    6208             :          * the original one. (This would happen when inheritance actually
    6209             :          * works..
    6210             :          */
    6211             :         closesocket(src->origsocket);
    6212             :     }
    6213             : }
    6214             : #endif
    6215             : 
    6216             : static void
    6217             : read_backend_variables(char *id, Port *port)
    6218             : {
    6219             :     BackendParameters param;
    6220             : 
    6221             : #ifndef WIN32
    6222             :     /* Non-win32 implementation reads from file */
    6223             :     FILE       *fp;
    6224             : 
    6225             :     /* Open file */
    6226             :     fp = AllocateFile(id, PG_BINARY_R);
    6227             :     if (!fp)
    6228             :     {
    6229             :         write_stderr("could not open backend variables file \"%s\": %s\n",
    6230             :                      id, strerror(errno));
    6231             :         exit(1);
    6232             :     }
    6233             : 
    6234             :     if (fread(&param, sizeof(param), 1, fp) != 1)
    6235             :     {
    6236             :         write_stderr("could not read from backend variables file \"%s\": %s\n",
    6237             :                      id, strerror(errno));
    6238             :         exit(1);
    6239             :     }
    6240             : 
    6241             :     /* Release file */
    6242             :     FreeFile(fp);
    6243             :     if (unlink(id) != 0)
    6244             :     {
    6245             :         write_stderr("could not remove file \"%s\": %s\n",
    6246             :                      id, strerror(errno));
    6247             :         exit(1);
    6248             :     }
    6249             : #else
    6250             :     /* Win32 version uses mapped file */
    6251             :     HANDLE      paramHandle;
    6252             :     BackendParameters *paramp;
    6253             : 
    6254             : #ifdef _WIN64
    6255             :     paramHandle = (HANDLE) _atoi64(id);
    6256             : #else
    6257             :     paramHandle = (HANDLE) atol(id);
    6258             : #endif
    6259             :     paramp = MapViewOfFile(paramHandle, FILE_MAP_READ, 0, 0, 0);
    6260             :     if (!paramp)
    6261             :     {
    6262             :         write_stderr("could not map view of backend variables: error code %lu\n",
    6263             :                      GetLastError());
    6264             :         exit(1);
    6265             :     }
    6266             : 
    6267             :     memcpy(&param, paramp, sizeof(BackendParameters));
    6268             : 
    6269             :     if (!UnmapViewOfFile(paramp))
    6270             :     {
    6271             :         write_stderr("could not unmap view of backend variables: error code %lu\n",
    6272             :                      GetLastError());
    6273             :         exit(1);
    6274             :     }
    6275             : 
    6276             :     if (!CloseHandle(paramHandle))
    6277             :     {
    6278             :         write_stderr("could not close handle to backend parameter variables: error code %lu\n",
    6279             :                      GetLastError());
    6280             :         exit(1);
    6281             :     }
    6282             : #endif
    6283             : 
    6284             :     restore_backend_variables(&param, port);
    6285             : }
    6286             : 
    6287             : /* Restore critical backend variables from the BackendParameters struct */
    6288             : static void
    6289             : restore_backend_variables(BackendParameters *param, Port *port)
    6290             : {
    6291             :     memcpy(port, &param->port, sizeof(Port));
    6292             :     read_inheritable_socket(&port->sock, &param->portsocket);
    6293             : 
    6294             :     SetDataDir(param->DataDir);
    6295             : 
    6296             :     memcpy(&ListenSocket, &param->ListenSocket, sizeof(ListenSocket));
    6297             : 
    6298             :     MyCancelKey = param->MyCancelKey;
    6299             :     MyPMChildSlot = param->MyPMChildSlot;
    6300             : 
    6301             : #ifdef WIN32
    6302             :     ShmemProtectiveRegion = param->ShmemProtectiveRegion;
    6303             : #endif
    6304             :     UsedShmemSegID = param->UsedShmemSegID;
    6305             :     UsedShmemSegAddr = param->UsedShmemSegAddr;
    6306             : 
    6307             :     ShmemLock = param->ShmemLock;
    6308             :     ShmemVariableCache = param->ShmemVariableCache;
    6309             :     ShmemBackendArray = param->ShmemBackendArray;
    6310             : 
    6311             : #ifndef HAVE_SPINLOCKS
    6312             :     SpinlockSemaArray = param->SpinlockSemaArray;
    6313             : #endif
    6314             :     NamedLWLockTrancheRequests = param->NamedLWLockTrancheRequests;
    6315             :     NamedLWLockTrancheArray = param->NamedLWLockTrancheArray;
    6316             :     MainLWLockArray = param->MainLWLockArray;
    6317             :     ProcStructLock = param->ProcStructLock;
    6318             :     ProcGlobal = param->ProcGlobal;
    6319             :     AuxiliaryProcs = param->AuxiliaryProcs;
    6320             :     PreparedXactProcs = param->PreparedXactProcs;
    6321             :     PMSignalState = param->PMSignalState;
    6322             :     read_inheritable_socket(&pgStatSock, &param->pgStatSock);
    6323             : 
    6324             :     PostmasterPid = param->PostmasterPid;
    6325             :     PgStartTime = param->PgStartTime;
    6326             :     PgReloadTime = param->PgReloadTime;
    6327             :     first_syslogger_file_time = param->first_syslogger_file_time;
    6328             : 
    6329             :     redirection_done = param->redirection_done;
    6330             :     IsBinaryUpgrade = param->IsBinaryUpgrade;
    6331             :     max_safe_fds = param->max_safe_fds;
    6332             : 
    6333             :     MaxBackends = param->MaxBackends;
    6334             : 
    6335             : #ifdef WIN32
    6336             :     PostmasterHandle = param->PostmasterHandle;
    6337             :     pgwin32_initial_signal_pipe = param->initial_signal_pipe;
    6338             : #else
    6339             :     memcpy(&postmaster_alive_fds, &param->postmaster_alive_fds,
    6340             :            sizeof(postmaster_alive_fds));
    6341             : #endif
    6342             : 
    6343             :     memcpy(&syslogPipe, &param->syslogPipe, sizeof(syslogPipe));
    6344             : 
    6345             :     strlcpy(my_exec_path, param->my_exec_path, MAXPGPATH);
    6346             : 
    6347             :     strlcpy(pkglib_path, param->pkglib_path, MAXPGPATH);
    6348             : 
    6349             :     strlcpy(ExtraOptions, param->ExtraOptions, MAXPGPATH);
    6350             : }
    6351             : 
    6352             : 
    6353             : Size
    6354             : ShmemBackendArraySize(void)
    6355             : {
    6356             :     return mul_size(MaxLivePostmasterChildren(), sizeof(Backend));
    6357             : }
    6358             : 
    6359             : void
    6360             : ShmemBackendArrayAllocation(void)
    6361             : {
    6362             :     Size        size = ShmemBackendArraySize();
    6363             : 
    6364             :     ShmemBackendArray = (Backend *) ShmemAlloc(size);
    6365             :     /* Mark all slots as empty */
    6366             :     memset(ShmemBackendArray, 0, size);
    6367             : }
    6368             : 
    6369             : static void
    6370             : ShmemBackendArrayAdd(Backend *bn)
    6371             : {
    6372             :     /* The array slot corresponding to my PMChildSlot should be free */
    6373             :     int         i = bn->child_slot - 1;
    6374             : 
    6375             :     Assert(ShmemBackendArray[i].pid == 0);
    6376             :     ShmemBackendArray[i] = *bn;
    6377             : }
    6378             : 
    6379             : static void
    6380             : ShmemBackendArrayRemove(Backend *bn)
    6381             : {
    6382             :     int         i = bn->child_slot - 1;
    6383             : 
    6384             :     Assert(ShmemBackendArray[i].pid == bn->pid);
    6385             :     /* Mark the slot as empty */
    6386             :     ShmemBackendArray[i].pid = 0;
    6387             : }
    6388             : #endif                          /* EXEC_BACKEND */
    6389             : 
    6390             : 
    6391             : #ifdef WIN32
    6392             : 
    6393             : /*
    6394             :  * Subset implementation of waitpid() for Windows.  We assume pid is -1
    6395             :  * (that is, check all child processes) and options is WNOHANG (don't wait).
    6396             :  */
    6397             : static pid_t
    6398             : waitpid(pid_t pid, int *exitstatus, int options)
    6399             : {
    6400             :     DWORD       dwd;
    6401             :     ULONG_PTR   key;
    6402             :     OVERLAPPED *ovl;
    6403             : 
    6404             :     /*
    6405             :      * Check if there are any dead children. If there are, return the pid of
    6406             :      * the first one that died.
    6407             :      */
    6408             :     if (GetQueuedCompletionStatus(win32ChildQueue, &dwd, &key, &ovl, 0))
    6409             :     {
    6410             :         *exitstatus = (int) key;
    6411             :         return dwd;
    6412             :     }
    6413             : 
    6414             :     return -1;
    6415             : }
    6416             : 
    6417             : /*
    6418             :  * Note! Code below executes on a thread pool! All operations must
    6419             :  * be thread safe! Note that elog() and friends must *not* be used.
    6420             :  */
    6421             : static void WINAPI
    6422             : pgwin32_deadchild_callback(PVOID lpParameter, BOOLEAN TimerOrWaitFired)
    6423             : {
    6424             :     win32_deadchild_waitinfo *childinfo = (win32_deadchild_waitinfo *) lpParameter;
    6425             :     DWORD       exitcode;
    6426             : 
    6427             :     if (TimerOrWaitFired)
    6428             :         return;                 /* timeout. Should never happen, since we use
    6429             :                                  * INFINITE as timeout value. */
    6430             : 
    6431             :     /*
    6432             :      * Remove handle from wait - required even though it's set to wait only
    6433             :      * once
    6434             :      */
    6435             :     UnregisterWaitEx(childinfo->waitHandle, NULL);
    6436             : 
    6437             :     if (!GetExitCodeProcess(childinfo->procHandle, &exitcode))
    6438             :     {
    6439             :         /*
    6440             :          * Should never happen. Inform user and set a fixed exitcode.
    6441             :          */
    6442             :         write_stderr("could not read exit code for process\n");
    6443             :         exitcode = 255;
    6444             :     }
    6445             : 
    6446             :     if (!PostQueuedCompletionStatus(win32ChildQueue, childinfo->procId, (ULONG_PTR) exitcode, NULL))
    6447             :         write_stderr("could not post child completion status\n");
    6448             : 
    6449             :     /*
    6450             :      * Handle is per-process, so we close it here instead of in the
    6451             :      * originating thread
    6452             :      */
    6453             :     CloseHandle(childinfo->procHandle);
    6454             : 
    6455             :     /*
    6456             :      * Free struct that was allocated before the call to
    6457             :      * RegisterWaitForSingleObject()
    6458             :      */
    6459             :     free(childinfo);
    6460             : 
    6461             :     /* Queue SIGCHLD signal */
    6462             :     pg_queue_signal(SIGCHLD);
    6463             : }
    6464             : #endif                          /* WIN32 */
    6465             : 
    6466             : /*
    6467             :  * Initialize one and only handle for monitoring postmaster death.
    6468             :  *
    6469             :  * Called once in the postmaster, so that child processes can subsequently
    6470             :  * monitor if their parent is dead.
    6471             :  */
    6472             : static void
    6473         572 : InitPostmasterDeathWatchHandle(void)
    6474             : {
    6475             : #ifndef WIN32
    6476             : 
    6477             :     /*
    6478             :      * Create a pipe. Postmaster holds the write end of the pipe open
    6479             :      * (POSTMASTER_FD_OWN), and children hold the read end. Children can pass
    6480             :      * the read file descriptor to select() to wake up in case postmaster
    6481             :      * dies, or check for postmaster death with a (read() == 0). Children must
    6482             :      * close the write end as soon as possible after forking, because EOF
    6483             :      * won't be signaled in the read end until all processes have closed the
    6484             :      * write fd. That is taken care of in ClosePostmasterPorts().
    6485             :      */
    6486             :     Assert(MyProcPid == PostmasterPid);
    6487         572 :     if (pipe(postmaster_alive_fds) < 0)
    6488           0 :         ereport(FATAL,
    6489             :                 (errcode_for_file_access(),
    6490             :                  errmsg_internal("could not create pipe to monitor postmaster death: %m")));
    6491             : 
    6492             :     /*
    6493             :      * Set O_NONBLOCK to allow testing for the fd's presence with a read()
    6494             :      * call.
    6495             :      */
    6496         572 :     if (fcntl(postmaster_alive_fds[POSTMASTER_FD_WATCH], F_SETFL, O_NONBLOCK) == -1)
    6497           0 :         ereport(FATAL,
    6498             :                 (errcode_for_socket_access(),
    6499             :                  errmsg_internal("could not set postmaster death monitoring pipe to nonblocking mode: %m")));
    6500             : #else
    6501             : 
    6502             :     /*
    6503             :      * On Windows, we use a process handle for the same purpose.
    6504             :      */
    6505             :     if (DuplicateHandle(GetCurrentProcess(),
    6506             :                         GetCurrentProcess(),
    6507             :                         GetCurrentProcess(),
    6508             :                         &PostmasterHandle,
    6509             :                         0,
    6510             :                         TRUE,
    6511             :                         DUPLICATE_SAME_ACCESS) == 0)
    6512             :         ereport(FATAL,
    6513             :                 (errmsg_internal("could not duplicate postmaster handle: error code %lu",
    6514             :                                  GetLastError())));
    6515             : #endif                          /* WIN32 */
    6516         572 : }

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