LCOV - code coverage report
Current view: top level - src/backend/utils/init - miscinit.c (source / functions) Hit Total Coverage
Test: PostgreSQL 19devel Lines: 365 460 79.3 %
Date: 2025-10-14 16:18:16 Functions: 48 51 94.1 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * miscinit.c
       4             :  *    miscellaneous initialization support stuff
       5             :  *
       6             :  * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994, Regents of the University of California
       8             :  *
       9             :  *
      10             :  * IDENTIFICATION
      11             :  *    src/backend/utils/init/miscinit.c
      12             :  *
      13             :  *-------------------------------------------------------------------------
      14             :  */
      15             : #include "postgres.h"
      16             : 
      17             : #include <sys/param.h>
      18             : #include <signal.h>
      19             : #include <time.h>
      20             : #include <sys/file.h>
      21             : #include <sys/stat.h>
      22             : #include <sys/time.h>
      23             : #include <fcntl.h>
      24             : #include <unistd.h>
      25             : #include <grp.h>
      26             : #include <pwd.h>
      27             : #include <netinet/in.h>
      28             : #include <arpa/inet.h>
      29             : #include <utime.h>
      30             : 
      31             : #include "access/htup_details.h"
      32             : #include "access/parallel.h"
      33             : #include "catalog/pg_authid.h"
      34             : #include "common/file_perm.h"
      35             : #include "libpq/libpq.h"
      36             : #include "libpq/pqsignal.h"
      37             : #include "mb/pg_wchar.h"
      38             : #include "miscadmin.h"
      39             : #include "pgstat.h"
      40             : #include "postmaster/autovacuum.h"
      41             : #include "postmaster/interrupt.h"
      42             : #include "postmaster/postmaster.h"
      43             : #include "replication/slotsync.h"
      44             : #include "storage/fd.h"
      45             : #include "storage/ipc.h"
      46             : #include "storage/latch.h"
      47             : #include "storage/pg_shmem.h"
      48             : #include "storage/pmsignal.h"
      49             : #include "storage/proc.h"
      50             : #include "storage/procarray.h"
      51             : #include "utils/builtins.h"
      52             : #include "utils/guc.h"
      53             : #include "utils/inval.h"
      54             : #include "utils/memutils.h"
      55             : #include "utils/pidfile.h"
      56             : #include "utils/syscache.h"
      57             : #include "utils/varlena.h"
      58             : 
      59             : 
      60             : #define DIRECTORY_LOCK_FILE     "postmaster.pid"
      61             : 
      62             : ProcessingMode Mode = InitProcessing;
      63             : 
      64             : BackendType MyBackendType;
      65             : 
      66             : /* List of lock files to be removed at proc exit */
      67             : static List *lock_files = NIL;
      68             : 
      69             : static Latch LocalLatchData;
      70             : 
      71             : /* ----------------------------------------------------------------
      72             :  *      ignoring system indexes support stuff
      73             :  *
      74             :  * NOTE: "ignoring system indexes" means we do not use the system indexes
      75             :  * for lookups (either in hardwired catalog accesses or in planner-generated
      76             :  * plans).  We do, however, still update the indexes when a catalog
      77             :  * modification is made.
      78             :  * ----------------------------------------------------------------
      79             :  */
      80             : 
      81             : bool        IgnoreSystemIndexes = false;
      82             : 
      83             : 
      84             : /* ----------------------------------------------------------------
      85             :  *  common process startup code
      86             :  * ----------------------------------------------------------------
      87             :  */
      88             : 
      89             : /*
      90             :  * Initialize the basic environment for a postmaster child
      91             :  *
      92             :  * Should be called as early as possible after the child's startup. However,
      93             :  * on EXEC_BACKEND builds it does need to be after read_backend_variables().
      94             :  */
      95             : void
      96       45180 : InitPostmasterChild(void)
      97             : {
      98       45180 :     IsUnderPostmaster = true;   /* we are a postmaster subprocess now */
      99             : 
     100             :     /*
     101             :      * Start our win32 signal implementation. This has to be done after we
     102             :      * read the backend variables, because we need to pick up the signal pipe
     103             :      * from the parent process.
     104             :      */
     105             : #ifdef WIN32
     106             :     pgwin32_signal_initialize();
     107             : #endif
     108             : 
     109       45180 :     InitProcessGlobals();
     110             : 
     111             :     /*
     112             :      * make sure stderr is in binary mode before anything can possibly be
     113             :      * written to it, in case it's actually the syslogger pipe, so the pipe
     114             :      * chunking protocol isn't disturbed. Non-logpipe data gets translated on
     115             :      * redirection (e.g. via pg_ctl -l) anyway.
     116             :      */
     117             : #ifdef WIN32
     118             :     _setmode(fileno(stderr), _O_BINARY);
     119             : #endif
     120             : 
     121             :     /* We don't want the postmaster's proc_exit() handlers */
     122       45180 :     on_exit_reset();
     123             : 
     124             :     /* In EXEC_BACKEND case we will not have inherited BlockSig etc values */
     125             : #ifdef EXEC_BACKEND
     126             :     pqinitmask();
     127             : #endif
     128             : 
     129             :     /* Initialize process-local latch support */
     130       45180 :     InitializeWaitEventSupport();
     131       45180 :     InitProcessLocalLatch();
     132       45180 :     InitializeLatchWaitSet();
     133             : 
     134             :     /*
     135             :      * If possible, make this process a group leader, so that the postmaster
     136             :      * can signal any child processes too. Not all processes will have
     137             :      * children, but for consistency we make all postmaster child processes do
     138             :      * this.
     139             :      */
     140             : #ifdef HAVE_SETSID
     141       45180 :     if (setsid() < 0)
     142           0 :         elog(FATAL, "setsid() failed: %m");
     143             : #endif
     144             : 
     145             :     /*
     146             :      * Every postmaster child process is expected to respond promptly to
     147             :      * SIGQUIT at all times.  Therefore we centrally remove SIGQUIT from
     148             :      * BlockSig and install a suitable signal handler.  (Client-facing
     149             :      * processes may choose to replace this default choice of handler with
     150             :      * quickdie().)  All other blockable signals remain blocked for now.
     151             :      */
     152       45180 :     pqsignal(SIGQUIT, SignalHandlerForCrashExit);
     153             : 
     154       45180 :     sigdelset(&BlockSig, SIGQUIT);
     155       45180 :     sigprocmask(SIG_SETMASK, &BlockSig, NULL);
     156             : 
     157             :     /* Request a signal if the postmaster dies, if possible. */
     158       45180 :     PostmasterDeathSignalInit();
     159             : 
     160             :     /* Don't give the pipe to subprograms that we execute. */
     161             : #ifndef WIN32
     162       45180 :     if (fcntl(postmaster_alive_fds[POSTMASTER_FD_WATCH], F_SETFD, FD_CLOEXEC) < 0)
     163           0 :         ereport(FATAL,
     164             :                 (errcode_for_socket_access(),
     165             :                  errmsg_internal("could not set postmaster death monitoring pipe to FD_CLOEXEC mode: %m")));
     166             : #endif
     167       45180 : }
     168             : 
     169             : /*
     170             :  * Initialize the basic environment for a standalone process.
     171             :  *
     172             :  * argv0 has to be suitable to find the program's executable.
     173             :  */
     174             : void
     175         492 : InitStandaloneProcess(const char *argv0)
     176             : {
     177             :     Assert(!IsPostmasterEnvironment);
     178             : 
     179         492 :     MyBackendType = B_STANDALONE_BACKEND;
     180             : 
     181             :     /*
     182             :      * Start our win32 signal implementation
     183             :      */
     184             : #ifdef WIN32
     185             :     pgwin32_signal_initialize();
     186             : #endif
     187             : 
     188         492 :     InitProcessGlobals();
     189             : 
     190             :     /* Initialize process-local latch support */
     191         492 :     InitializeWaitEventSupport();
     192         492 :     InitProcessLocalLatch();
     193         492 :     InitializeLatchWaitSet();
     194             : 
     195             :     /*
     196             :      * For consistency with InitPostmasterChild, initialize signal mask here.
     197             :      * But we don't unblock SIGQUIT or provide a default handler for it.
     198             :      */
     199         492 :     pqinitmask();
     200         492 :     sigprocmask(SIG_SETMASK, &BlockSig, NULL);
     201             : 
     202             :     /* Compute paths, no postmaster to inherit from */
     203         492 :     if (my_exec_path[0] == '\0')
     204             :     {
     205         492 :         if (find_my_exec(argv0, my_exec_path) < 0)
     206           0 :             elog(FATAL, "%s: could not locate my own executable path",
     207             :                  argv0);
     208             :     }
     209             : 
     210         492 :     if (pkglib_path[0] == '\0')
     211         492 :         get_pkglib_path(my_exec_path, pkglib_path);
     212         492 : }
     213             : 
     214             : void
     215       44680 : SwitchToSharedLatch(void)
     216             : {
     217             :     Assert(MyLatch == &LocalLatchData);
     218             :     Assert(MyProc != NULL);
     219             : 
     220       44680 :     MyLatch = &MyProc->procLatch;
     221             : 
     222       44680 :     if (FeBeWaitSet)
     223       26116 :         ModifyWaitEvent(FeBeWaitSet, FeBeWaitSetLatchPos, WL_LATCH_SET,
     224             :                         MyLatch);
     225             : 
     226             :     /*
     227             :      * Set the shared latch as the local one might have been set. This
     228             :      * shouldn't normally be necessary as code is supposed to check the
     229             :      * condition before waiting for the latch, but a bit care can't hurt.
     230             :      */
     231       44680 :     SetLatch(MyLatch);
     232       44680 : }
     233             : 
     234             : void
     235       47436 : InitProcessLocalLatch(void)
     236             : {
     237       47436 :     MyLatch = &LocalLatchData;
     238       47436 :     InitLatch(MyLatch);
     239       47436 : }
     240             : 
     241             : void
     242       44680 : SwitchBackToLocalLatch(void)
     243             : {
     244             :     Assert(MyLatch != &LocalLatchData);
     245             :     Assert(MyProc != NULL && MyLatch == &MyProc->procLatch);
     246             : 
     247       44680 :     MyLatch = &LocalLatchData;
     248             : 
     249       44680 :     if (FeBeWaitSet)
     250       26116 :         ModifyWaitEvent(FeBeWaitSet, FeBeWaitSetLatchPos, WL_LATCH_SET,
     251             :                         MyLatch);
     252             : 
     253       44680 :     SetLatch(MyLatch);
     254       44680 : }
     255             : 
     256             : /*
     257             :  * Return a human-readable string representation of a BackendType.
     258             :  *
     259             :  * The string is not localized here, but we mark the strings for translation
     260             :  * so that callers can invoke _() on the result.
     261             :  */
     262             : const char *
     263     1652926 : GetBackendTypeDesc(BackendType backendType)
     264             : {
     265     1652926 :     const char *backendDesc = gettext_noop("unknown process type");
     266             : 
     267     1652926 :     switch (backendType)
     268             :     {
     269             : #define PG_PROCTYPE(bktype, description, main_func, shmem_attach)   \
     270             :         case bktype: backendDesc = description; break;
     271             : #include "postmaster/proctypelist.h"
     272             : #undef PG_PROCTYPE
     273             :     }
     274     1652926 :     return backendDesc;
     275             : }
     276             : 
     277             : /* ----------------------------------------------------------------
     278             :  *              database path / name support stuff
     279             :  * ----------------------------------------------------------------
     280             :  */
     281             : 
     282             : void
     283       33328 : SetDatabasePath(const char *path)
     284             : {
     285             :     /* This should happen only once per process */
     286             :     Assert(!DatabasePath);
     287       33328 :     DatabasePath = MemoryContextStrdup(TopMemoryContext, path);
     288       33328 : }
     289             : 
     290             : /*
     291             :  * Validate the proposed data directory.
     292             :  *
     293             :  * Also initialize file and directory create modes and mode mask.
     294             :  */
     295             : void
     296        2192 : checkDataDir(void)
     297             : {
     298             :     struct stat stat_buf;
     299             : 
     300             :     Assert(DataDir);
     301             : 
     302        2192 :     if (stat(DataDir, &stat_buf) != 0)
     303             :     {
     304           0 :         if (errno == ENOENT)
     305           0 :             ereport(FATAL,
     306             :                     (errcode_for_file_access(),
     307             :                      errmsg("data directory \"%s\" does not exist",
     308             :                             DataDir)));
     309             :         else
     310           0 :             ereport(FATAL,
     311             :                     (errcode_for_file_access(),
     312             :                      errmsg("could not read permissions of directory \"%s\": %m",
     313             :                             DataDir)));
     314             :     }
     315             : 
     316             :     /* eventual chdir would fail anyway, but let's test ... */
     317        2192 :     if (!S_ISDIR(stat_buf.st_mode))
     318           0 :         ereport(FATAL,
     319             :                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
     320             :                  errmsg("specified data directory \"%s\" is not a directory",
     321             :                         DataDir)));
     322             : 
     323             :     /*
     324             :      * Check that the directory belongs to my userid; if not, reject.
     325             :      *
     326             :      * This check is an essential part of the interlock that prevents two
     327             :      * postmasters from starting in the same directory (see CreateLockFile()).
     328             :      * Do not remove or weaken it.
     329             :      *
     330             :      * XXX can we safely enable this check on Windows?
     331             :      */
     332             : #if !defined(WIN32) && !defined(__CYGWIN__)
     333        2192 :     if (stat_buf.st_uid != geteuid())
     334           0 :         ereport(FATAL,
     335             :                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
     336             :                  errmsg("data directory \"%s\" has wrong ownership",
     337             :                         DataDir),
     338             :                  errhint("The server must be started by the user that owns the data directory.")));
     339             : #endif
     340             : 
     341             :     /*
     342             :      * Check if the directory has correct permissions.  If not, reject.
     343             :      *
     344             :      * Only two possible modes are allowed, 0700 and 0750.  The latter mode
     345             :      * indicates that group read/execute should be allowed on all newly
     346             :      * created files and directories.
     347             :      *
     348             :      * XXX temporarily suppress check when on Windows, because there may not
     349             :      * be proper support for Unix-y file permissions.  Need to think of a
     350             :      * reasonable check to apply on Windows.
     351             :      */
     352             : #if !defined(WIN32) && !defined(__CYGWIN__)
     353        2192 :     if (stat_buf.st_mode & PG_MODE_MASK_GROUP)
     354           0 :         ereport(FATAL,
     355             :                 (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
     356             :                  errmsg("data directory \"%s\" has invalid permissions",
     357             :                         DataDir),
     358             :                  errdetail("Permissions should be u=rwx (0700) or u=rwx,g=rx (0750).")));
     359             : #endif
     360             : 
     361             :     /*
     362             :      * Reset creation modes and mask based on the mode of the data directory.
     363             :      *
     364             :      * The mask was set earlier in startup to disallow group permissions on
     365             :      * newly created files and directories.  However, if group read/execute
     366             :      * are present on the data directory then modify the create modes and mask
     367             :      * to allow group read/execute on newly created files and directories and
     368             :      * set the data_directory_mode GUC.
     369             :      *
     370             :      * Suppress when on Windows, because there may not be proper support for
     371             :      * Unix-y file permissions.
     372             :      */
     373             : #if !defined(WIN32) && !defined(__CYGWIN__)
     374        2192 :     SetDataDirectoryCreatePerm(stat_buf.st_mode);
     375             : 
     376        2192 :     umask(pg_mode_mask);
     377        2192 :     data_directory_mode = pg_dir_create_mode;
     378             : #endif
     379             : 
     380             :     /* Check for PG_VERSION */
     381        2192 :     ValidatePgVersion(DataDir);
     382        2192 : }
     383             : 
     384             : /*
     385             :  * Set data directory, but make sure it's an absolute path.  Use this,
     386             :  * never set DataDir directly.
     387             :  */
     388             : void
     389        2204 : SetDataDir(const char *dir)
     390             : {
     391             :     char       *new;
     392             : 
     393             :     Assert(dir);
     394             : 
     395             :     /* If presented path is relative, convert to absolute */
     396        2204 :     new = make_absolute_path(dir);
     397             : 
     398        2204 :     free(DataDir);
     399        2204 :     DataDir = new;
     400        2204 : }
     401             : 
     402             : /*
     403             :  * Change working directory to DataDir.  Most of the postmaster and backend
     404             :  * code assumes that we are in DataDir so it can use relative paths to access
     405             :  * stuff in and under the data directory.  For convenience during path
     406             :  * setup, however, we don't force the chdir to occur during SetDataDir.
     407             :  */
     408             : void
     409        2192 : ChangeToDataDir(void)
     410             : {
     411             :     Assert(DataDir);
     412             : 
     413        2192 :     if (chdir(DataDir) < 0)
     414           0 :         ereport(FATAL,
     415             :                 (errcode_for_file_access(),
     416             :                  errmsg("could not change directory to \"%s\": %m",
     417             :                         DataDir)));
     418        2192 : }
     419             : 
     420             : 
     421             : /* ----------------------------------------------------------------
     422             :  *  User ID state
     423             :  *
     424             :  * We have to track several different values associated with the concept
     425             :  * of "user ID".
     426             :  *
     427             :  * AuthenticatedUserId is determined at connection start and never changes.
     428             :  *
     429             :  * SessionUserId is initially the same as AuthenticatedUserId, but can be
     430             :  * changed by SET SESSION AUTHORIZATION (if AuthenticatedUserId is a
     431             :  * superuser).  This is the ID reported by the SESSION_USER SQL function.
     432             :  *
     433             :  * OuterUserId is the current user ID in effect at the "outer level" (outside
     434             :  * any transaction or function).  This is initially the same as SessionUserId,
     435             :  * but can be changed by SET ROLE to any role that SessionUserId is a
     436             :  * member of.  (XXX rename to something like CurrentRoleId?)
     437             :  *
     438             :  * CurrentUserId is the current effective user ID; this is the one to use
     439             :  * for all normal permissions-checking purposes.  At outer level this will
     440             :  * be the same as OuterUserId, but it changes during calls to SECURITY
     441             :  * DEFINER functions, as well as locally in some specialized commands.
     442             :  *
     443             :  * SecurityRestrictionContext holds flags indicating reason(s) for changing
     444             :  * CurrentUserId.  In some cases we need to lock down operations that are
     445             :  * not directly controlled by privilege settings, and this provides a
     446             :  * convenient way to do it.
     447             :  * ----------------------------------------------------------------
     448             :  */
     449             : static Oid  AuthenticatedUserId = InvalidOid;
     450             : static Oid  SessionUserId = InvalidOid;
     451             : static Oid  OuterUserId = InvalidOid;
     452             : static Oid  CurrentUserId = InvalidOid;
     453             : static const char *SystemUser = NULL;
     454             : 
     455             : /* We also have to remember the superuser state of the session user */
     456             : static bool SessionUserIsSuperuser = false;
     457             : 
     458             : static int  SecurityRestrictionContext = 0;
     459             : 
     460             : /* We also remember if a SET ROLE is currently active */
     461             : static bool SetRoleIsActive = false;
     462             : 
     463             : /*
     464             :  * GetUserId - get the current effective user ID.
     465             :  *
     466             :  * Note: there's no SetUserId() anymore; use SetUserIdAndSecContext().
     467             :  */
     468             : Oid
     469    13746456 : GetUserId(void)
     470             : {
     471             :     Assert(OidIsValid(CurrentUserId));
     472    13746456 :     return CurrentUserId;
     473             : }
     474             : 
     475             : 
     476             : /*
     477             :  * GetOuterUserId/SetOuterUserId - get/set the outer-level user ID.
     478             :  */
     479             : Oid
     480        1562 : GetOuterUserId(void)
     481             : {
     482             :     Assert(OidIsValid(OuterUserId));
     483        1562 :     return OuterUserId;
     484             : }
     485             : 
     486             : 
     487             : static void
     488       84474 : SetOuterUserId(Oid userid, bool is_superuser)
     489             : {
     490             :     Assert(SecurityRestrictionContext == 0);
     491             :     Assert(OidIsValid(userid));
     492       84474 :     OuterUserId = userid;
     493             : 
     494             :     /* We force the effective user ID to match, too */
     495       84474 :     CurrentUserId = userid;
     496             : 
     497             :     /* Also update the is_superuser GUC to match OuterUserId's property */
     498       84474 :     SetConfigOption("is_superuser",
     499             :                     is_superuser ? "on" : "off",
     500             :                     PGC_INTERNAL, PGC_S_DYNAMIC_DEFAULT);
     501       84474 : }
     502             : 
     503             : 
     504             : /*
     505             :  * GetSessionUserId/SetSessionUserId - get/set the session user ID.
     506             :  */
     507             : Oid
     508       70774 : GetSessionUserId(void)
     509             : {
     510             :     Assert(OidIsValid(SessionUserId));
     511       70774 :     return SessionUserId;
     512             : }
     513             : 
     514             : bool
     515        3668 : GetSessionUserIsSuperuser(void)
     516             : {
     517             :     Assert(OidIsValid(SessionUserId));
     518        3668 :     return SessionUserIsSuperuser;
     519             : }
     520             : 
     521             : static void
     522       41404 : SetSessionUserId(Oid userid, bool is_superuser)
     523             : {
     524             :     Assert(SecurityRestrictionContext == 0);
     525             :     Assert(OidIsValid(userid));
     526       41404 :     SessionUserId = userid;
     527       41404 :     SessionUserIsSuperuser = is_superuser;
     528       41404 : }
     529             : 
     530             : /*
     531             :  * Return the system user representing the authenticated identity.
     532             :  * It is defined in InitializeSystemUser() as auth_method:authn_id.
     533             :  */
     534             : const char *
     535          44 : GetSystemUser(void)
     536             : {
     537          44 :     return SystemUser;
     538             : }
     539             : 
     540             : /*
     541             :  * GetAuthenticatedUserId/SetAuthenticatedUserId - get/set the authenticated
     542             :  * user ID
     543             :  */
     544             : Oid
     545       33128 : GetAuthenticatedUserId(void)
     546             : {
     547             :     Assert(OidIsValid(AuthenticatedUserId));
     548       33128 :     return AuthenticatedUserId;
     549             : }
     550             : 
     551             : void
     552       29772 : SetAuthenticatedUserId(Oid userid)
     553             : {
     554             :     Assert(OidIsValid(userid));
     555             : 
     556             :     /* call only once */
     557             :     Assert(!OidIsValid(AuthenticatedUserId));
     558             : 
     559       29772 :     AuthenticatedUserId = userid;
     560             : 
     561             :     /* Also mark our PGPROC entry with the authenticated user id */
     562             :     /* (We assume this is an atomic store so no lock is needed) */
     563       29772 :     MyProc->roleId = userid;
     564       29772 : }
     565             : 
     566             : 
     567             : /*
     568             :  * GetUserIdAndSecContext/SetUserIdAndSecContext - get/set the current user ID
     569             :  * and the SecurityRestrictionContext flags.
     570             :  *
     571             :  * Currently there are three valid bits in SecurityRestrictionContext:
     572             :  *
     573             :  * SECURITY_LOCAL_USERID_CHANGE indicates that we are inside an operation
     574             :  * that is temporarily changing CurrentUserId via these functions.  This is
     575             :  * needed to indicate that the actual value of CurrentUserId is not in sync
     576             :  * with guc.c's internal state, so SET ROLE has to be disallowed.
     577             :  *
     578             :  * SECURITY_RESTRICTED_OPERATION indicates that we are inside an operation
     579             :  * that does not wish to trust called user-defined functions at all.  The
     580             :  * policy is to use this before operations, e.g. autovacuum and REINDEX, that
     581             :  * enumerate relations of a database or schema and run functions associated
     582             :  * with each found relation.  The relation owner is the new user ID.  Set this
     583             :  * as soon as possible after locking the relation.  Restore the old user ID as
     584             :  * late as possible before closing the relation; restoring it shortly after
     585             :  * close is also tolerable.  If a command has both relation-enumerating and
     586             :  * non-enumerating modes, e.g. ANALYZE, both modes set this bit.  This bit
     587             :  * prevents not only SET ROLE, but various other changes of session state that
     588             :  * normally is unprotected but might possibly be used to subvert the calling
     589             :  * session later.  An example is replacing an existing prepared statement with
     590             :  * new code, which will then be executed with the outer session's permissions
     591             :  * when the prepared statement is next used.  These restrictions are fairly
     592             :  * draconian, but the functions called in relation-enumerating operations are
     593             :  * really supposed to be side-effect-free anyway.
     594             :  *
     595             :  * SECURITY_NOFORCE_RLS indicates that we are inside an operation which should
     596             :  * ignore the FORCE ROW LEVEL SECURITY per-table indication.  This is used to
     597             :  * ensure that FORCE RLS does not mistakenly break referential integrity
     598             :  * checks.  Note that this is intentionally only checked when running as the
     599             :  * owner of the table (which should always be the case for referential
     600             :  * integrity checks).
     601             :  *
     602             :  * Unlike GetUserId, GetUserIdAndSecContext does *not* Assert that the current
     603             :  * value of CurrentUserId is valid; nor does SetUserIdAndSecContext require
     604             :  * the new value to be valid.  In fact, these routines had better not
     605             :  * ever throw any kind of error.  This is because they are used by
     606             :  * StartTransaction and AbortTransaction to save/restore the settings,
     607             :  * and during the first transaction within a backend, the value to be saved
     608             :  * and perhaps restored is indeed invalid.  We have to be able to get
     609             :  * through AbortTransaction without asserting in case InitPostgres fails.
     610             :  */
     611             : void
     612     1859150 : GetUserIdAndSecContext(Oid *userid, int *sec_context)
     613             : {
     614     1859150 :     *userid = CurrentUserId;
     615     1859150 :     *sec_context = SecurityRestrictionContext;
     616     1859150 : }
     617             : 
     618             : void
     619     1509258 : SetUserIdAndSecContext(Oid userid, int sec_context)
     620             : {
     621     1509258 :     CurrentUserId = userid;
     622     1509258 :     SecurityRestrictionContext = sec_context;
     623     1509258 : }
     624             : 
     625             : 
     626             : /*
     627             :  * InLocalUserIdChange - are we inside a local change of CurrentUserId?
     628             :  */
     629             : bool
     630       68004 : InLocalUserIdChange(void)
     631             : {
     632       68004 :     return (SecurityRestrictionContext & SECURITY_LOCAL_USERID_CHANGE) != 0;
     633             : }
     634             : 
     635             : /*
     636             :  * InSecurityRestrictedOperation - are we inside a security-restricted command?
     637             :  */
     638             : bool
     639       80322 : InSecurityRestrictedOperation(void)
     640             : {
     641       80322 :     return (SecurityRestrictionContext & SECURITY_RESTRICTED_OPERATION) != 0;
     642             : }
     643             : 
     644             : /*
     645             :  * InNoForceRLSOperation - are we ignoring FORCE ROW LEVEL SECURITY ?
     646             :  */
     647             : bool
     648         264 : InNoForceRLSOperation(void)
     649             : {
     650         264 :     return (SecurityRestrictionContext & SECURITY_NOFORCE_RLS) != 0;
     651             : }
     652             : 
     653             : 
     654             : /*
     655             :  * These are obsolete versions of Get/SetUserIdAndSecContext that are
     656             :  * only provided for bug-compatibility with some rather dubious code in
     657             :  * pljava.  We allow the userid to be set, but only when not inside a
     658             :  * security restriction context.
     659             :  */
     660             : void
     661           0 : GetUserIdAndContext(Oid *userid, bool *sec_def_context)
     662             : {
     663           0 :     *userid = CurrentUserId;
     664           0 :     *sec_def_context = InLocalUserIdChange();
     665           0 : }
     666             : 
     667             : void
     668           0 : SetUserIdAndContext(Oid userid, bool sec_def_context)
     669             : {
     670             :     /* We throw the same error SET ROLE would. */
     671           0 :     if (InSecurityRestrictedOperation())
     672           0 :         ereport(ERROR,
     673             :                 (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
     674             :                  errmsg("cannot set parameter \"%s\" within security-restricted operation",
     675             :                         "role")));
     676           0 :     CurrentUserId = userid;
     677           0 :     if (sec_def_context)
     678           0 :         SecurityRestrictionContext |= SECURITY_LOCAL_USERID_CHANGE;
     679             :     else
     680           0 :         SecurityRestrictionContext &= ~SECURITY_LOCAL_USERID_CHANGE;
     681           0 : }
     682             : 
     683             : 
     684             : /*
     685             :  * Check whether specified role has explicit REPLICATION privilege
     686             :  */
     687             : bool
     688        3472 : has_rolreplication(Oid roleid)
     689             : {
     690        3472 :     bool        result = false;
     691             :     HeapTuple   utup;
     692             : 
     693             :     /* Superusers bypass all permission checking. */
     694        3472 :     if (superuser_arg(roleid))
     695        3362 :         return true;
     696             : 
     697         110 :     utup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(roleid));
     698         110 :     if (HeapTupleIsValid(utup))
     699             :     {
     700         110 :         result = ((Form_pg_authid) GETSTRUCT(utup))->rolreplication;
     701         110 :         ReleaseSysCache(utup);
     702             :     }
     703         110 :     return result;
     704             : }
     705             : 
     706             : /*
     707             :  * Initialize user identity during normal backend startup
     708             :  */
     709             : void
     710       29776 : InitializeSessionUserId(const char *rolename, Oid roleid,
     711             :                         bool bypass_login_check)
     712             : {
     713             :     HeapTuple   roleTup;
     714             :     Form_pg_authid rform;
     715             :     char       *rname;
     716             :     bool        is_superuser;
     717             : 
     718             :     /*
     719             :      * In a parallel worker, we don't have to do anything here.
     720             :      * ParallelWorkerMain already set our output variables, and we aren't
     721             :      * going to enforce either rolcanlogin or rolconnlimit.  Furthermore, we
     722             :      * don't really want to perform a catalog lookup for the role: we don't
     723             :      * want to fail if it's been dropped.
     724             :      */
     725       29776 :     if (InitializingParallelWorker)
     726             :     {
     727             :         Assert(bypass_login_check);
     728        2752 :         return;
     729             :     }
     730             : 
     731             :     /*
     732             :      * Don't do scans if we're bootstrapping, none of the system catalogs
     733             :      * exist yet, and they should be owned by postgres anyway.
     734             :      */
     735             :     Assert(!IsBootstrapProcessingMode());
     736             : 
     737             :     /*
     738             :      * Make sure syscache entries are flushed for recent catalog changes. This
     739             :      * allows us to find roles that were created on-the-fly during
     740             :      * authentication.
     741             :      */
     742       27024 :     AcceptInvalidationMessages();
     743             : 
     744             :     /*
     745             :      * Look up the role, either by name if that's given or by OID if not.
     746             :      */
     747       27024 :     if (rolename != NULL)
     748             :     {
     749       25984 :         roleTup = SearchSysCache1(AUTHNAME, PointerGetDatum(rolename));
     750       25984 :         if (!HeapTupleIsValid(roleTup))
     751           4 :             ereport(FATAL,
     752             :                     (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
     753             :                      errmsg("role \"%s\" does not exist", rolename)));
     754             :     }
     755             :     else
     756             :     {
     757        1040 :         roleTup = SearchSysCache1(AUTHOID, ObjectIdGetDatum(roleid));
     758        1040 :         if (!HeapTupleIsValid(roleTup))
     759           0 :             ereport(FATAL,
     760             :                     (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
     761             :                      errmsg("role with OID %u does not exist", roleid)));
     762             :     }
     763             : 
     764       27020 :     rform = (Form_pg_authid) GETSTRUCT(roleTup);
     765       27020 :     roleid = rform->oid;
     766       27020 :     rname = NameStr(rform->rolname);
     767       27020 :     is_superuser = rform->rolsuper;
     768             : 
     769       27020 :     SetAuthenticatedUserId(roleid);
     770             : 
     771             :     /*
     772             :      * Set SessionUserId and related variables, including "role", via the GUC
     773             :      * mechanisms.
     774             :      *
     775             :      * Note: ideally we would use PGC_S_DYNAMIC_DEFAULT here, so that
     776             :      * session_authorization could subsequently be changed from
     777             :      * pg_db_role_setting entries.  Instead, session_authorization in
     778             :      * pg_db_role_setting has no effect.  Changing that would require solving
     779             :      * two problems:
     780             :      *
     781             :      * 1. If pg_db_role_setting has values for both session_authorization and
     782             :      * role, we could not be sure which order those would be applied in, and
     783             :      * it would matter.
     784             :      *
     785             :      * 2. Sites may have years-old session_authorization entries.  There's not
     786             :      * been any particular reason to remove them.  Ending the dormancy of
     787             :      * those entries could seriously change application behavior, so only a
     788             :      * major release should do that.
     789             :      */
     790       27020 :     SetConfigOption("session_authorization", rname,
     791             :                     PGC_BACKEND, PGC_S_OVERRIDE);
     792             : 
     793             :     /*
     794             :      * These next checks are not enforced when in standalone mode, so that
     795             :      * there is a way to recover from sillinesses like "UPDATE pg_authid SET
     796             :      * rolcanlogin = false;".
     797             :      */
     798       27020 :     if (IsUnderPostmaster)
     799             :     {
     800             :         /*
     801             :          * Is role allowed to login at all?  (But background workers can
     802             :          * override this by setting bypass_login_check.)
     803             :          */
     804       27020 :         if (!bypass_login_check && !rform->rolcanlogin)
     805           6 :             ereport(FATAL,
     806             :                     (errcode(ERRCODE_INVALID_AUTHORIZATION_SPECIFICATION),
     807             :                      errmsg("role \"%s\" is not permitted to log in",
     808             :                             rname)));
     809             : 
     810             :         /*
     811             :          * Check connection limit for this role.  We enforce the limit only
     812             :          * for regular backends, since other process types have their own
     813             :          * PGPROC pools.
     814             :          *
     815             :          * There is a race condition here --- we create our PGPROC before
     816             :          * checking for other PGPROCs.  If two backends did this at about the
     817             :          * same time, they might both think they were over the limit, while
     818             :          * ideally one should succeed and one fail.  Getting that to work
     819             :          * exactly seems more trouble than it is worth, however; instead we
     820             :          * just document that the connection limit is approximate.
     821             :          */
     822       27014 :         if (rform->rolconnlimit >= 0 &&
     823           0 :             AmRegularBackendProcess() &&
     824           0 :             !is_superuser &&
     825           0 :             CountUserBackends(roleid) > rform->rolconnlimit)
     826           0 :             ereport(FATAL,
     827             :                     (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
     828             :                      errmsg("too many connections for role \"%s\"",
     829             :                             rname)));
     830             :     }
     831             : 
     832       27014 :     ReleaseSysCache(roleTup);
     833             : }
     834             : 
     835             : 
     836             : /*
     837             :  * Initialize user identity during special backend startup
     838             :  */
     839             : void
     840        5366 : InitializeSessionUserIdStandalone(void)
     841             : {
     842             :     /*
     843             :      * This function should only be called in single-user mode, in autovacuum
     844             :      * workers, in slot sync worker and in background workers.
     845             :      */
     846             :     Assert(!IsUnderPostmaster || AmAutoVacuumWorkerProcess() ||
     847             :            AmLogicalSlotSyncWorkerProcess() || AmBackgroundWorkerProcess());
     848             : 
     849             :     /* call only once */
     850             :     Assert(!OidIsValid(AuthenticatedUserId));
     851             : 
     852        5366 :     AuthenticatedUserId = BOOTSTRAP_SUPERUSERID;
     853             : 
     854             :     /*
     855             :      * XXX Ideally we'd do this via SetConfigOption("session_authorization"),
     856             :      * but we lack the role name needed to do that, and we can't fetch it
     857             :      * because one reason for this special case is to be able to start up even
     858             :      * if something's happened to the BOOTSTRAP_SUPERUSERID's pg_authid row.
     859             :      * Since we don't set the GUC itself, C code will see the value as NULL,
     860             :      * and current_setting() will report an empty string within this session.
     861             :      */
     862        5366 :     SetSessionAuthorization(BOOTSTRAP_SUPERUSERID, true);
     863             : 
     864             :     /* We could do SetConfigOption("role"), but let's be consistent */
     865        5366 :     SetCurrentRoleId(InvalidOid, false);
     866        5366 : }
     867             : 
     868             : /*
     869             :  * Initialize the system user.
     870             :  *
     871             :  * This is built as auth_method:authn_id.
     872             :  */
     873             : void
     874         252 : InitializeSystemUser(const char *authn_id, const char *auth_method)
     875             : {
     876             :     char       *system_user;
     877             : 
     878             :     /* call only once */
     879             :     Assert(SystemUser == NULL);
     880             : 
     881             :     /*
     882             :      * InitializeSystemUser should be called only when authn_id is not NULL,
     883             :      * meaning that auth_method is valid.
     884             :      */
     885             :     Assert(authn_id != NULL);
     886             : 
     887         252 :     system_user = psprintf("%s:%s", auth_method, authn_id);
     888             : 
     889             :     /* Store SystemUser in long-lived storage */
     890         252 :     SystemUser = MemoryContextStrdup(TopMemoryContext, system_user);
     891         252 :     pfree(system_user);
     892         252 : }
     893             : 
     894             : /*
     895             :  * SQL-function SYSTEM_USER
     896             :  */
     897             : Datum
     898          44 : system_user(PG_FUNCTION_ARGS)
     899             : {
     900          44 :     const char *sysuser = GetSystemUser();
     901             : 
     902          44 :     if (sysuser)
     903          22 :         PG_RETURN_DATUM(CStringGetTextDatum(sysuser));
     904             :     else
     905          22 :         PG_RETURN_NULL();
     906             : }
     907             : 
     908             : /*
     909             :  * Change session auth ID while running
     910             :  *
     911             :  * The SQL standard says that SET SESSION AUTHORIZATION implies SET ROLE NONE.
     912             :  * We mechanize that at higher levels not here, because this is the GUC
     913             :  * assign hook for "session_authorization", and it must be commutative with
     914             :  * SetCurrentRoleId (the hook for "role") because guc.c provides no guarantees
     915             :  * which will run first during cases such as transaction rollback.  Therefore,
     916             :  * we update derived state (OuterUserId/CurrentUserId/is_superuser) only if
     917             :  * !SetRoleIsActive.
     918             :  */
     919             : void
     920       41404 : SetSessionAuthorization(Oid userid, bool is_superuser)
     921             : {
     922       41404 :     SetSessionUserId(userid, is_superuser);
     923             : 
     924       41404 :     if (!SetRoleIsActive)
     925       41336 :         SetOuterUserId(userid, is_superuser);
     926       41404 : }
     927             : 
     928             : /*
     929             :  * Report current role id
     930             :  *      This follows the semantics of SET ROLE, ie return the outer-level ID
     931             :  *      not the current effective ID, and return InvalidOid when the setting
     932             :  *      is logically SET ROLE NONE.
     933             :  */
     934             : Oid
     935         988 : GetCurrentRoleId(void)
     936             : {
     937         988 :     if (SetRoleIsActive)
     938          60 :         return OuterUserId;
     939             :     else
     940         928 :         return InvalidOid;
     941             : }
     942             : 
     943             : /*
     944             :  * Change Role ID while running (SET ROLE)
     945             :  *
     946             :  * If roleid is InvalidOid, we are doing SET ROLE NONE: revert to the
     947             :  * session user authorization.  In this case the is_superuser argument
     948             :  * is ignored.
     949             :  *
     950             :  * When roleid is not InvalidOid, the caller must have checked whether
     951             :  * the session user has permission to become that role.  (We cannot check
     952             :  * here because this routine must be able to execute in a failed transaction
     953             :  * to restore a prior value of the ROLE GUC variable.)
     954             :  */
     955             : void
     956       45394 : SetCurrentRoleId(Oid roleid, bool is_superuser)
     957             : {
     958             :     /*
     959             :      * Get correct info if it's SET ROLE NONE
     960             :      *
     961             :      * If SessionUserId hasn't been set yet, do nothing beyond updating
     962             :      * SetRoleIsActive --- the eventual SetSessionAuthorization call will
     963             :      * update the derived state.  This is needed since we will get called
     964             :      * during GUC initialization.
     965             :      */
     966       45394 :     if (!OidIsValid(roleid))
     967             :     {
     968       44360 :         SetRoleIsActive = false;
     969             : 
     970       44360 :         if (!OidIsValid(SessionUserId))
     971        2256 :             return;
     972             : 
     973       42104 :         roleid = SessionUserId;
     974       42104 :         is_superuser = SessionUserIsSuperuser;
     975             :     }
     976             :     else
     977        1034 :         SetRoleIsActive = true;
     978             : 
     979       43138 :     SetOuterUserId(roleid, is_superuser);
     980             : }
     981             : 
     982             : 
     983             : /*
     984             :  * Get user name from user oid, returns NULL for nonexistent roleid if noerr
     985             :  * is true.
     986             :  */
     987             : char *
     988       21352 : GetUserNameFromId(Oid roleid, bool noerr)
     989             : {
     990             :     HeapTuple   tuple;
     991             :     char       *result;
     992             : 
     993       21352 :     tuple = SearchSysCache1(AUTHOID, ObjectIdGetDatum(roleid));
     994       21352 :     if (!HeapTupleIsValid(tuple))
     995             :     {
     996          18 :         if (!noerr)
     997           0 :             ereport(ERROR,
     998             :                     (errcode(ERRCODE_UNDEFINED_OBJECT),
     999             :                      errmsg("invalid role OID: %u", roleid)));
    1000          18 :         result = NULL;
    1001             :     }
    1002             :     else
    1003             :     {
    1004       21334 :         result = pstrdup(NameStr(((Form_pg_authid) GETSTRUCT(tuple))->rolname));
    1005       21334 :         ReleaseSysCache(tuple);
    1006             :     }
    1007       21352 :     return result;
    1008             : }
    1009             : 
    1010             : /* ------------------------------------------------------------------------
    1011             :  *              Client connection state shared with parallel workers
    1012             :  *
    1013             :  * ClientConnectionInfo contains pieces of information about the client that
    1014             :  * need to be synced to parallel workers when they initialize.
    1015             :  *-------------------------------------------------------------------------
    1016             :  */
    1017             : 
    1018             : ClientConnectionInfo MyClientConnectionInfo;
    1019             : 
    1020             : /*
    1021             :  * Intermediate representation of ClientConnectionInfo for easier
    1022             :  * serialization.  Variable-length fields are allocated right after this
    1023             :  * header.
    1024             :  */
    1025             : typedef struct SerializedClientConnectionInfo
    1026             : {
    1027             :     int32       authn_id_len;   /* strlen(authn_id), or -1 if NULL */
    1028             :     UserAuth    auth_method;
    1029             : } SerializedClientConnectionInfo;
    1030             : 
    1031             : /*
    1032             :  * Calculate the space needed to serialize MyClientConnectionInfo.
    1033             :  */
    1034             : Size
    1035         916 : EstimateClientConnectionInfoSpace(void)
    1036             : {
    1037         916 :     Size        size = 0;
    1038             : 
    1039         916 :     size = add_size(size, sizeof(SerializedClientConnectionInfo));
    1040             : 
    1041         916 :     if (MyClientConnectionInfo.authn_id)
    1042           2 :         size = add_size(size, strlen(MyClientConnectionInfo.authn_id) + 1);
    1043             : 
    1044         916 :     return size;
    1045             : }
    1046             : 
    1047             : /*
    1048             :  * Serialize MyClientConnectionInfo for use by parallel workers.
    1049             :  */
    1050             : void
    1051         916 : SerializeClientConnectionInfo(Size maxsize PG_USED_FOR_ASSERTS_ONLY,
    1052             :                               char *start_address)
    1053             : {
    1054         916 :     SerializedClientConnectionInfo serialized = {0};
    1055             : 
    1056         916 :     serialized.authn_id_len = -1;
    1057         916 :     serialized.auth_method = MyClientConnectionInfo.auth_method;
    1058             : 
    1059         916 :     if (MyClientConnectionInfo.authn_id)
    1060           2 :         serialized.authn_id_len = strlen(MyClientConnectionInfo.authn_id);
    1061             : 
    1062             :     /* Copy serialized representation to buffer */
    1063             :     Assert(maxsize >= sizeof(serialized));
    1064         916 :     memcpy(start_address, &serialized, sizeof(serialized));
    1065             : 
    1066         916 :     maxsize -= sizeof(serialized);
    1067         916 :     start_address += sizeof(serialized);
    1068             : 
    1069             :     /* Copy authn_id into the space after the struct */
    1070         916 :     if (serialized.authn_id_len >= 0)
    1071             :     {
    1072             :         Assert(maxsize >= (serialized.authn_id_len + 1));
    1073           2 :         memcpy(start_address,
    1074           2 :                MyClientConnectionInfo.authn_id,
    1075             :         /* include the NULL terminator to ease deserialization */
    1076           2 :                serialized.authn_id_len + 1);
    1077             :     }
    1078         916 : }
    1079             : 
    1080             : /*
    1081             :  * Restore MyClientConnectionInfo from its serialized representation.
    1082             :  */
    1083             : void
    1084        2752 : RestoreClientConnectionInfo(char *conninfo)
    1085             : {
    1086             :     SerializedClientConnectionInfo serialized;
    1087             : 
    1088        2752 :     memcpy(&serialized, conninfo, sizeof(serialized));
    1089             : 
    1090             :     /* Copy the fields back into place */
    1091        2752 :     MyClientConnectionInfo.authn_id = NULL;
    1092        2752 :     MyClientConnectionInfo.auth_method = serialized.auth_method;
    1093             : 
    1094        2752 :     if (serialized.authn_id_len >= 0)
    1095             :     {
    1096             :         char       *authn_id;
    1097             : 
    1098           4 :         authn_id = conninfo + sizeof(serialized);
    1099           4 :         MyClientConnectionInfo.authn_id = MemoryContextStrdup(TopMemoryContext,
    1100             :                                                               authn_id);
    1101             :     }
    1102        2752 : }
    1103             : 
    1104             : 
    1105             : /*-------------------------------------------------------------------------
    1106             :  *              Interlock-file support
    1107             :  *
    1108             :  * These routines are used to create both a data-directory lockfile
    1109             :  * ($DATADIR/postmaster.pid) and Unix-socket-file lockfiles ($SOCKFILE.lock).
    1110             :  * Both kinds of files contain the same info initially, although we can add
    1111             :  * more information to a data-directory lockfile after it's created, using
    1112             :  * AddToDataDirLockFile().  See pidfile.h for documentation of the contents
    1113             :  * of these lockfiles.
    1114             :  *
    1115             :  * On successful lockfile creation, a proc_exit callback to remove the
    1116             :  * lockfile is automatically created.
    1117             :  *-------------------------------------------------------------------------
    1118             :  */
    1119             : 
    1120             : /*
    1121             :  * proc_exit callback to remove lockfiles.
    1122             :  */
    1123             : static void
    1124        2186 : UnlinkLockFiles(int status, Datum arg)
    1125             : {
    1126             :     ListCell   *l;
    1127             : 
    1128        6102 :     foreach(l, lock_files)
    1129             :     {
    1130        3916 :         char       *curfile = (char *) lfirst(l);
    1131             : 
    1132        3916 :         unlink(curfile);
    1133             :         /* Should we complain if the unlink fails? */
    1134             :     }
    1135             :     /* Since we're about to exit, no need to reclaim storage */
    1136             : 
    1137             :     /*
    1138             :      * Lock file removal should always be the last externally visible action
    1139             :      * of a postmaster or standalone backend, while we won't come here at all
    1140             :      * when exiting postmaster child processes.  Therefore, this is a good
    1141             :      * place to log completion of shutdown.  We could alternatively teach
    1142             :      * proc_exit() to do it, but that seems uglier.  In a standalone backend,
    1143             :      * use NOTICE elevel to be less chatty.
    1144             :      */
    1145        2186 :     ereport(IsPostmasterEnvironment ? LOG : NOTICE,
    1146             :             (errmsg("database system is shut down")));
    1147        2186 : }
    1148             : 
    1149             : /*
    1150             :  * Create a lockfile.
    1151             :  *
    1152             :  * filename is the path name of the lockfile to create.
    1153             :  * amPostmaster is used to determine how to encode the output PID.
    1154             :  * socketDir is the Unix socket directory path to include (possibly empty).
    1155             :  * isDDLock and refName are used to determine what error message to produce.
    1156             :  */
    1157             : static void
    1158        3922 : CreateLockFile(const char *filename, bool amPostmaster,
    1159             :                const char *socketDir,
    1160             :                bool isDDLock, const char *refName)
    1161             : {
    1162             :     int         fd;
    1163             :     char        buffer[MAXPGPATH * 2 + 256];
    1164             :     int         ntries;
    1165             :     int         len;
    1166             :     int         encoded_pid;
    1167             :     pid_t       other_pid;
    1168             :     pid_t       my_pid,
    1169             :                 my_p_pid,
    1170             :                 my_gp_pid;
    1171             :     const char *envvar;
    1172             : 
    1173             :     /*
    1174             :      * If the PID in the lockfile is our own PID or our parent's or
    1175             :      * grandparent's PID, then the file must be stale (probably left over from
    1176             :      * a previous system boot cycle).  We need to check this because of the
    1177             :      * likelihood that a reboot will assign exactly the same PID as we had in
    1178             :      * the previous reboot, or one that's only one or two counts larger and
    1179             :      * hence the lockfile's PID now refers to an ancestor shell process.  We
    1180             :      * allow pg_ctl to pass down its parent shell PID (our grandparent PID)
    1181             :      * via the environment variable PG_GRANDPARENT_PID; this is so that
    1182             :      * launching the postmaster via pg_ctl can be just as reliable as
    1183             :      * launching it directly.  There is no provision for detecting
    1184             :      * further-removed ancestor processes, but if the init script is written
    1185             :      * carefully then all but the immediate parent shell will be root-owned
    1186             :      * processes and so the kill test will fail with EPERM.  Note that we
    1187             :      * cannot get a false negative this way, because an existing postmaster
    1188             :      * would surely never launch a competing postmaster or pg_ctl process
    1189             :      * directly.
    1190             :      */
    1191        3922 :     my_pid = getpid();
    1192             : 
    1193             : #ifndef WIN32
    1194        3922 :     my_p_pid = getppid();
    1195             : #else
    1196             : 
    1197             :     /*
    1198             :      * Windows hasn't got getppid(), but doesn't need it since it's not using
    1199             :      * real kill() either...
    1200             :      */
    1201             :     my_p_pid = 0;
    1202             : #endif
    1203             : 
    1204        3922 :     envvar = getenv("PG_GRANDPARENT_PID");
    1205        3922 :     if (envvar)
    1206        3098 :         my_gp_pid = atoi(envvar);
    1207             :     else
    1208         824 :         my_gp_pid = 0;
    1209             : 
    1210             :     /*
    1211             :      * We need a loop here because of race conditions.  But don't loop forever
    1212             :      * (for example, a non-writable $PGDATA directory might cause a failure
    1213             :      * that won't go away).  100 tries seems like plenty.
    1214             :      */
    1215        3922 :     for (ntries = 0;; ntries++)
    1216             :     {
    1217             :         /*
    1218             :          * Try to create the lock file --- O_EXCL makes this atomic.
    1219             :          *
    1220             :          * Think not to make the file protection weaker than 0600/0640.  See
    1221             :          * comments below.
    1222             :          */
    1223        3928 :         fd = open(filename, O_RDWR | O_CREAT | O_EXCL, pg_file_create_mode);
    1224        3928 :         if (fd >= 0)
    1225        3916 :             break;              /* Success; exit the retry loop */
    1226             : 
    1227             :         /*
    1228             :          * Couldn't create the pid file. Probably it already exists.
    1229             :          */
    1230          12 :         if ((errno != EEXIST && errno != EACCES) || ntries > 100)
    1231           0 :             ereport(FATAL,
    1232             :                     (errcode_for_file_access(),
    1233             :                      errmsg("could not create lock file \"%s\": %m",
    1234             :                             filename)));
    1235             : 
    1236             :         /*
    1237             :          * Read the file to get the old owner's PID.  Note race condition
    1238             :          * here: file might have been deleted since we tried to create it.
    1239             :          */
    1240          12 :         fd = open(filename, O_RDONLY, pg_file_create_mode);
    1241          12 :         if (fd < 0)
    1242             :         {
    1243           0 :             if (errno == ENOENT)
    1244           0 :                 continue;       /* race condition; try again */
    1245           0 :             ereport(FATAL,
    1246             :                     (errcode_for_file_access(),
    1247             :                      errmsg("could not open lock file \"%s\": %m",
    1248             :                             filename)));
    1249             :         }
    1250          12 :         pgstat_report_wait_start(WAIT_EVENT_LOCK_FILE_CREATE_READ);
    1251          12 :         if ((len = read(fd, buffer, sizeof(buffer) - 1)) < 0)
    1252           0 :             ereport(FATAL,
    1253             :                     (errcode_for_file_access(),
    1254             :                      errmsg("could not read lock file \"%s\": %m",
    1255             :                             filename)));
    1256          12 :         pgstat_report_wait_end();
    1257          12 :         close(fd);
    1258             : 
    1259          12 :         if (len == 0)
    1260             :         {
    1261           0 :             ereport(FATAL,
    1262             :                     (errcode(ERRCODE_LOCK_FILE_EXISTS),
    1263             :                      errmsg("lock file \"%s\" is empty", filename),
    1264             :                      errhint("Either another server is starting, or the lock file is the remnant of a previous server startup crash.")));
    1265             :         }
    1266             : 
    1267          12 :         buffer[len] = '\0';
    1268          12 :         encoded_pid = atoi(buffer);
    1269             : 
    1270             :         /* if pid < 0, the pid is for postgres, not postmaster */
    1271          12 :         other_pid = (pid_t) (encoded_pid < 0 ? -encoded_pid : encoded_pid);
    1272             : 
    1273          12 :         if (other_pid <= 0)
    1274           0 :             elog(FATAL, "bogus data in lock file \"%s\": \"%s\"",
    1275             :                  filename, buffer);
    1276             : 
    1277             :         /*
    1278             :          * Check to see if the other process still exists
    1279             :          *
    1280             :          * Per discussion above, my_pid, my_p_pid, and my_gp_pid can be
    1281             :          * ignored as false matches.
    1282             :          *
    1283             :          * Normally kill() will fail with ESRCH if the given PID doesn't
    1284             :          * exist.
    1285             :          *
    1286             :          * We can treat the EPERM-error case as okay because that error
    1287             :          * implies that the existing process has a different userid than we
    1288             :          * do, which means it cannot be a competing postmaster.  A postmaster
    1289             :          * cannot successfully attach to a data directory owned by a userid
    1290             :          * other than its own, as enforced in checkDataDir(). Also, since we
    1291             :          * create the lockfiles mode 0600/0640, we'd have failed above if the
    1292             :          * lockfile belonged to another userid --- which means that whatever
    1293             :          * process kill() is reporting about isn't the one that made the
    1294             :          * lockfile.  (NOTE: this last consideration is the only one that
    1295             :          * keeps us from blowing away a Unix socket file belonging to an
    1296             :          * instance of Postgres being run by someone else, at least on
    1297             :          * machines where /tmp hasn't got a stickybit.)
    1298             :          */
    1299          12 :         if (other_pid != my_pid && other_pid != my_p_pid &&
    1300             :             other_pid != my_gp_pid)
    1301             :         {
    1302          12 :             if (kill(other_pid, 0) == 0 ||
    1303           8 :                 (errno != ESRCH && errno != EPERM))
    1304             :             {
    1305             :                 /* lockfile belongs to a live process */
    1306           4 :                 ereport(FATAL,
    1307             :                         (errcode(ERRCODE_LOCK_FILE_EXISTS),
    1308             :                          errmsg("lock file \"%s\" already exists",
    1309             :                                 filename),
    1310             :                          isDDLock ?
    1311             :                          (encoded_pid < 0 ?
    1312             :                           errhint("Is another postgres (PID %d) running in data directory \"%s\"?",
    1313             :                                   (int) other_pid, refName) :
    1314             :                           errhint("Is another postmaster (PID %d) running in data directory \"%s\"?",
    1315             :                                   (int) other_pid, refName)) :
    1316             :                          (encoded_pid < 0 ?
    1317             :                           errhint("Is another postgres (PID %d) using socket file \"%s\"?",
    1318             :                                   (int) other_pid, refName) :
    1319             :                           errhint("Is another postmaster (PID %d) using socket file \"%s\"?",
    1320             :                                   (int) other_pid, refName))));
    1321             :             }
    1322             :         }
    1323             : 
    1324             :         /*
    1325             :          * No, the creating process did not exist.  However, it could be that
    1326             :          * the postmaster crashed (or more likely was kill -9'd by a clueless
    1327             :          * admin) but has left orphan backends behind.  Check for this by
    1328             :          * looking to see if there is an associated shmem segment that is
    1329             :          * still in use.
    1330             :          *
    1331             :          * Note: because postmaster.pid is written in multiple steps, we might
    1332             :          * not find the shmem ID values in it; we can't treat that as an
    1333             :          * error.
    1334             :          */
    1335           8 :         if (isDDLock)
    1336             :         {
    1337           4 :             char       *ptr = buffer;
    1338             :             unsigned long id1,
    1339             :                         id2;
    1340             :             int         lineno;
    1341             : 
    1342          28 :             for (lineno = 1; lineno < LOCK_FILE_LINE_SHMEM_KEY; lineno++)
    1343             :             {
    1344          24 :                 if ((ptr = strchr(ptr, '\n')) == NULL)
    1345           0 :                     break;
    1346          24 :                 ptr++;
    1347             :             }
    1348             : 
    1349           4 :             if (ptr != NULL &&
    1350           4 :                 sscanf(ptr, "%lu %lu", &id1, &id2) == 2)
    1351             :             {
    1352           4 :                 if (PGSharedMemoryIsInUse(id1, id2))
    1353           2 :                     ereport(FATAL,
    1354             :                             (errcode(ERRCODE_LOCK_FILE_EXISTS),
    1355             :                              errmsg("pre-existing shared memory block (key %lu, ID %lu) is still in use",
    1356             :                                     id1, id2),
    1357             :                              errhint("Terminate any old server processes associated with data directory \"%s\".",
    1358             :                                      refName)));
    1359             :             }
    1360             :         }
    1361             : 
    1362             :         /*
    1363             :          * Looks like nobody's home.  Unlink the file and try again to create
    1364             :          * it.  Need a loop because of possible race condition against other
    1365             :          * would-be creators.
    1366             :          */
    1367           6 :         if (unlink(filename) < 0)
    1368           0 :             ereport(FATAL,
    1369             :                     (errcode_for_file_access(),
    1370             :                      errmsg("could not remove old lock file \"%s\": %m",
    1371             :                             filename),
    1372             :                      errhint("The file seems accidentally left over, but "
    1373             :                              "it could not be removed. Please remove the file "
    1374             :                              "by hand and try again.")));
    1375             :     }
    1376             : 
    1377             :     /*
    1378             :      * Successfully created the file, now fill it.  See comment in pidfile.h
    1379             :      * about the contents.  Note that we write the same first five lines into
    1380             :      * both datadir and socket lockfiles; although more stuff may get added to
    1381             :      * the datadir lockfile later.
    1382             :      */
    1383        3916 :     snprintf(buffer, sizeof(buffer), "%d\n%s\n" INT64_FORMAT "\n%d\n%s\n",
    1384             :              amPostmaster ? (int) my_pid : -((int) my_pid),
    1385             :              DataDir,
    1386             :              MyStartTime,
    1387             :              PostPortNumber,
    1388             :              socketDir);
    1389             : 
    1390             :     /*
    1391             :      * In a standalone backend, the next line (LOCK_FILE_LINE_LISTEN_ADDR)
    1392             :      * will never receive data, so fill it in as empty now.
    1393             :      */
    1394        3916 :     if (isDDLock && !amPostmaster)
    1395         440 :         strlcat(buffer, "\n", sizeof(buffer));
    1396             : 
    1397        3916 :     errno = 0;
    1398        3916 :     pgstat_report_wait_start(WAIT_EVENT_LOCK_FILE_CREATE_WRITE);
    1399        3916 :     if (write(fd, buffer, strlen(buffer)) != strlen(buffer))
    1400             :     {
    1401           0 :         int         save_errno = errno;
    1402             : 
    1403           0 :         close(fd);
    1404           0 :         unlink(filename);
    1405             :         /* if write didn't set errno, assume problem is no disk space */
    1406           0 :         errno = save_errno ? save_errno : ENOSPC;
    1407           0 :         ereport(FATAL,
    1408             :                 (errcode_for_file_access(),
    1409             :                  errmsg("could not write lock file \"%s\": %m", filename)));
    1410             :     }
    1411        3916 :     pgstat_report_wait_end();
    1412             : 
    1413        3916 :     pgstat_report_wait_start(WAIT_EVENT_LOCK_FILE_CREATE_SYNC);
    1414        3916 :     if (pg_fsync(fd) != 0)
    1415             :     {
    1416           0 :         int         save_errno = errno;
    1417             : 
    1418           0 :         close(fd);
    1419           0 :         unlink(filename);
    1420           0 :         errno = save_errno;
    1421           0 :         ereport(FATAL,
    1422             :                 (errcode_for_file_access(),
    1423             :                  errmsg("could not write lock file \"%s\": %m", filename)));
    1424             :     }
    1425        3916 :     pgstat_report_wait_end();
    1426        3916 :     if (close(fd) != 0)
    1427             :     {
    1428           0 :         int         save_errno = errno;
    1429             : 
    1430           0 :         unlink(filename);
    1431           0 :         errno = save_errno;
    1432           0 :         ereport(FATAL,
    1433             :                 (errcode_for_file_access(),
    1434             :                  errmsg("could not write lock file \"%s\": %m", filename)));
    1435             :     }
    1436             : 
    1437             :     /*
    1438             :      * Arrange to unlink the lock file(s) at proc_exit.  If this is the first
    1439             :      * one, set up the on_proc_exit function to do it; then add this lock file
    1440             :      * to the list of files to unlink.
    1441             :      */
    1442        3916 :     if (lock_files == NIL)
    1443        2186 :         on_proc_exit(UnlinkLockFiles, 0);
    1444             : 
    1445             :     /*
    1446             :      * Use lcons so that the lock files are unlinked in reverse order of
    1447             :      * creation; this is critical!
    1448             :      */
    1449        3916 :     lock_files = lcons(pstrdup(filename), lock_files);
    1450        3916 : }
    1451             : 
    1452             : /*
    1453             :  * Create the data directory lockfile.
    1454             :  *
    1455             :  * When this is called, we must have already switched the working
    1456             :  * directory to DataDir, so we can just use a relative path.  This
    1457             :  * helps ensure that we are locking the directory we should be.
    1458             :  *
    1459             :  * Note that the socket directory path line is initially written as empty.
    1460             :  * postmaster.c will rewrite it upon creating the first Unix socket.
    1461             :  */
    1462             : void
    1463        2192 : CreateDataDirLockFile(bool amPostmaster)
    1464             : {
    1465        2192 :     CreateLockFile(DIRECTORY_LOCK_FILE, amPostmaster, "", true, DataDir);
    1466        2186 : }
    1467             : 
    1468             : /*
    1469             :  * Create a lockfile for the specified Unix socket file.
    1470             :  */
    1471             : void
    1472        1730 : CreateSocketLockFile(const char *socketfile, bool amPostmaster,
    1473             :                      const char *socketDir)
    1474             : {
    1475             :     char        lockfile[MAXPGPATH];
    1476             : 
    1477        1730 :     snprintf(lockfile, sizeof(lockfile), "%s.lock", socketfile);
    1478        1730 :     CreateLockFile(lockfile, amPostmaster, socketDir, false, socketfile);
    1479        1730 : }
    1480             : 
    1481             : /*
    1482             :  * TouchSocketLockFiles -- mark socket lock files as recently accessed
    1483             :  *
    1484             :  * This routine should be called every so often to ensure that the socket
    1485             :  * lock files have a recent mod or access date.  That saves them
    1486             :  * from being removed by overenthusiastic /tmp-directory-cleaner daemons.
    1487             :  * (Another reason we should never have put the socket file in /tmp...)
    1488             :  */
    1489             : void
    1490           0 : TouchSocketLockFiles(void)
    1491             : {
    1492             :     ListCell   *l;
    1493             : 
    1494           0 :     foreach(l, lock_files)
    1495             :     {
    1496           0 :         char       *socketLockFile = (char *) lfirst(l);
    1497             : 
    1498             :         /* No need to touch the data directory lock file, we trust */
    1499           0 :         if (strcmp(socketLockFile, DIRECTORY_LOCK_FILE) == 0)
    1500           0 :             continue;
    1501             : 
    1502             :         /* we just ignore any error here */
    1503           0 :         (void) utime(socketLockFile, NULL);
    1504             :     }
    1505           0 : }
    1506             : 
    1507             : 
    1508             : /*
    1509             :  * Add (or replace) a line in the data directory lock file.
    1510             :  * The given string should not include a trailing newline.
    1511             :  *
    1512             :  * Note: because we don't truncate the file, if we were to rewrite a line
    1513             :  * with less data than it had before, there would be garbage after the last
    1514             :  * line.  While we could fix that by adding a truncate call, that would make
    1515             :  * the file update non-atomic, which we'd rather avoid.  Therefore, callers
    1516             :  * should endeavor never to shorten a line once it's been written.
    1517             :  */
    1518             : void
    1519       10932 : AddToDataDirLockFile(int target_line, const char *str)
    1520             : {
    1521             :     int         fd;
    1522             :     int         len;
    1523             :     int         lineno;
    1524             :     char       *srcptr;
    1525             :     char       *destptr;
    1526             :     char        srcbuffer[BLCKSZ];
    1527             :     char        destbuffer[BLCKSZ];
    1528             : 
    1529       10932 :     fd = open(DIRECTORY_LOCK_FILE, O_RDWR | PG_BINARY, 0);
    1530       10932 :     if (fd < 0)
    1531             :     {
    1532           0 :         ereport(LOG,
    1533             :                 (errcode_for_file_access(),
    1534             :                  errmsg("could not open file \"%s\": %m",
    1535             :                         DIRECTORY_LOCK_FILE)));
    1536           0 :         return;
    1537             :     }
    1538       10932 :     pgstat_report_wait_start(WAIT_EVENT_LOCK_FILE_ADDTODATADIR_READ);
    1539       10932 :     len = read(fd, srcbuffer, sizeof(srcbuffer) - 1);
    1540       10932 :     pgstat_report_wait_end();
    1541       10932 :     if (len < 0)
    1542             :     {
    1543           0 :         ereport(LOG,
    1544             :                 (errcode_for_file_access(),
    1545             :                  errmsg("could not read from file \"%s\": %m",
    1546             :                         DIRECTORY_LOCK_FILE)));
    1547           0 :         close(fd);
    1548           0 :         return;
    1549             :     }
    1550       10932 :     srcbuffer[len] = '\0';
    1551             : 
    1552             :     /*
    1553             :      * Advance over lines we are not supposed to rewrite, then copy them to
    1554             :      * destbuffer.
    1555             :      */
    1556       10932 :     srcptr = srcbuffer;
    1557       74890 :     for (lineno = 1; lineno < target_line; lineno++)
    1558             :     {
    1559       65690 :         char       *eol = strchr(srcptr, '\n');
    1560             : 
    1561       65690 :         if (eol == NULL)
    1562        1732 :             break;              /* not enough lines in file yet */
    1563       63958 :         srcptr = eol + 1;
    1564             :     }
    1565       10932 :     memcpy(destbuffer, srcbuffer, srcptr - srcbuffer);
    1566       10932 :     destptr = destbuffer + (srcptr - srcbuffer);
    1567             : 
    1568             :     /*
    1569             :      * Fill in any missing lines before the target line, in case lines are
    1570             :      * added to the file out of order.
    1571             :      */
    1572       12664 :     for (; lineno < target_line; lineno++)
    1573             :     {
    1574        1732 :         if (destptr < destbuffer + sizeof(destbuffer))
    1575        1732 :             *destptr++ = '\n';
    1576             :     }
    1577             : 
    1578             :     /*
    1579             :      * Write or rewrite the target line.
    1580             :      */
    1581       10932 :     snprintf(destptr, destbuffer + sizeof(destbuffer) - destptr, "%s\n", str);
    1582       10932 :     destptr += strlen(destptr);
    1583             : 
    1584             :     /*
    1585             :      * If there are more lines in the old file, append them to destbuffer.
    1586             :      */
    1587       10932 :     if ((srcptr = strchr(srcptr, '\n')) != NULL)
    1588             :     {
    1589        7030 :         srcptr++;
    1590        7030 :         snprintf(destptr, destbuffer + sizeof(destbuffer) - destptr, "%s",
    1591             :                  srcptr);
    1592             :     }
    1593             : 
    1594             :     /*
    1595             :      * And rewrite the data.  Since we write in a single kernel call, this
    1596             :      * update should appear atomic to onlookers.
    1597             :      */
    1598       10932 :     len = strlen(destbuffer);
    1599       10932 :     errno = 0;
    1600       10932 :     pgstat_report_wait_start(WAIT_EVENT_LOCK_FILE_ADDTODATADIR_WRITE);
    1601       10932 :     if (pg_pwrite(fd, destbuffer, len, 0) != len)
    1602             :     {
    1603           0 :         pgstat_report_wait_end();
    1604             :         /* if write didn't set errno, assume problem is no disk space */
    1605           0 :         if (errno == 0)
    1606           0 :             errno = ENOSPC;
    1607           0 :         ereport(LOG,
    1608             :                 (errcode_for_file_access(),
    1609             :                  errmsg("could not write to file \"%s\": %m",
    1610             :                         DIRECTORY_LOCK_FILE)));
    1611           0 :         close(fd);
    1612           0 :         return;
    1613             :     }
    1614       10932 :     pgstat_report_wait_end();
    1615       10932 :     pgstat_report_wait_start(WAIT_EVENT_LOCK_FILE_ADDTODATADIR_SYNC);
    1616       10932 :     if (pg_fsync(fd) != 0)
    1617             :     {
    1618           0 :         ereport(LOG,
    1619             :                 (errcode_for_file_access(),
    1620             :                  errmsg("could not write to file \"%s\": %m",
    1621             :                         DIRECTORY_LOCK_FILE)));
    1622             :     }
    1623       10932 :     pgstat_report_wait_end();
    1624       10932 :     if (close(fd) != 0)
    1625             :     {
    1626           0 :         ereport(LOG,
    1627             :                 (errcode_for_file_access(),
    1628             :                  errmsg("could not write to file \"%s\": %m",
    1629             :                         DIRECTORY_LOCK_FILE)));
    1630             :     }
    1631             : }
    1632             : 
    1633             : 
    1634             : /*
    1635             :  * Recheck that the data directory lock file still exists with expected
    1636             :  * content.  Return true if the lock file appears OK, false if it isn't.
    1637             :  *
    1638             :  * We call this periodically in the postmaster.  The idea is that if the
    1639             :  * lock file has been removed or replaced by another postmaster, we should
    1640             :  * do a panic database shutdown.  Therefore, we should return true if there
    1641             :  * is any doubt: we do not want to cause a panic shutdown unnecessarily.
    1642             :  * Transient failures like EINTR or ENFILE should not cause us to fail.
    1643             :  * (If there really is something wrong, we'll detect it on a future recheck.)
    1644             :  */
    1645             : bool
    1646          62 : RecheckDataDirLockFile(void)
    1647             : {
    1648             :     int         fd;
    1649             :     int         len;
    1650             :     long        file_pid;
    1651             :     char        buffer[BLCKSZ];
    1652             : 
    1653          62 :     fd = open(DIRECTORY_LOCK_FILE, O_RDWR | PG_BINARY, 0);
    1654          62 :     if (fd < 0)
    1655             :     {
    1656             :         /*
    1657             :          * There are many foreseeable false-positive error conditions.  For
    1658             :          * safety, fail only on enumerated clearly-something-is-wrong
    1659             :          * conditions.
    1660             :          */
    1661           0 :         switch (errno)
    1662             :         {
    1663           0 :             case ENOENT:
    1664             :             case ENOTDIR:
    1665             :                 /* disaster */
    1666           0 :                 ereport(LOG,
    1667             :                         (errcode_for_file_access(),
    1668             :                          errmsg("could not open file \"%s\": %m",
    1669             :                                 DIRECTORY_LOCK_FILE)));
    1670           0 :                 return false;
    1671           0 :             default:
    1672             :                 /* non-fatal, at least for now */
    1673           0 :                 ereport(LOG,
    1674             :                         (errcode_for_file_access(),
    1675             :                          errmsg("could not open file \"%s\": %m; continuing anyway",
    1676             :                                 DIRECTORY_LOCK_FILE)));
    1677           0 :                 return true;
    1678             :         }
    1679             :     }
    1680          62 :     pgstat_report_wait_start(WAIT_EVENT_LOCK_FILE_RECHECKDATADIR_READ);
    1681          62 :     len = read(fd, buffer, sizeof(buffer) - 1);
    1682          62 :     pgstat_report_wait_end();
    1683          62 :     if (len < 0)
    1684             :     {
    1685           0 :         ereport(LOG,
    1686             :                 (errcode_for_file_access(),
    1687             :                  errmsg("could not read from file \"%s\": %m",
    1688             :                         DIRECTORY_LOCK_FILE)));
    1689           0 :         close(fd);
    1690           0 :         return true;            /* treat read failure as nonfatal */
    1691             :     }
    1692          62 :     buffer[len] = '\0';
    1693          62 :     close(fd);
    1694          62 :     file_pid = atol(buffer);
    1695          62 :     if (file_pid == getpid())
    1696          62 :         return true;            /* all is well */
    1697             : 
    1698             :     /* Trouble: someone's overwritten the lock file */
    1699           0 :     ereport(LOG,
    1700             :             (errmsg("lock file \"%s\" contains wrong PID: %ld instead of %ld",
    1701             :                     DIRECTORY_LOCK_FILE, file_pid, (long) getpid())));
    1702           0 :     return false;
    1703             : }
    1704             : 
    1705             : 
    1706             : /*-------------------------------------------------------------------------
    1707             :  *              Version checking support
    1708             :  *-------------------------------------------------------------------------
    1709             :  */
    1710             : 
    1711             : /*
    1712             :  * Determine whether the PG_VERSION file in directory `path' indicates
    1713             :  * a data version compatible with the version of this program.
    1714             :  *
    1715             :  * If compatible, return. Otherwise, ereport(FATAL).
    1716             :  */
    1717             : void
    1718       35420 : ValidatePgVersion(const char *path)
    1719             : {
    1720             :     char        full_path[MAXPGPATH];
    1721             :     FILE       *file;
    1722             :     int         ret;
    1723             :     long        file_major;
    1724             :     long        my_major;
    1725             :     char       *endptr;
    1726             :     char        file_version_string[64];
    1727       35420 :     const char *my_version_string = PG_VERSION;
    1728             : 
    1729       35420 :     my_major = strtol(my_version_string, &endptr, 10);
    1730             : 
    1731       35420 :     snprintf(full_path, sizeof(full_path), "%s/PG_VERSION", path);
    1732             : 
    1733       35420 :     file = AllocateFile(full_path, "r");
    1734       35420 :     if (!file)
    1735             :     {
    1736           0 :         if (errno == ENOENT)
    1737           0 :             ereport(FATAL,
    1738             :                     (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    1739             :                      errmsg("\"%s\" is not a valid data directory",
    1740             :                             path),
    1741             :                      errdetail("File \"%s\" is missing.", full_path)));
    1742             :         else
    1743           0 :             ereport(FATAL,
    1744             :                     (errcode_for_file_access(),
    1745             :                      errmsg("could not open file \"%s\": %m", full_path)));
    1746             :     }
    1747             : 
    1748       35420 :     file_version_string[0] = '\0';
    1749       35420 :     ret = fscanf(file, "%63s", file_version_string);
    1750       35420 :     file_major = strtol(file_version_string, &endptr, 10);
    1751             : 
    1752       35420 :     if (ret != 1 || endptr == file_version_string)
    1753           0 :         ereport(FATAL,
    1754             :                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    1755             :                  errmsg("\"%s\" is not a valid data directory",
    1756             :                         path),
    1757             :                  errdetail("File \"%s\" does not contain valid data.",
    1758             :                            full_path),
    1759             :                  errhint("You might need to initdb.")));
    1760             : 
    1761       35420 :     FreeFile(file);
    1762             : 
    1763       35420 :     if (my_major != file_major)
    1764           0 :         ereport(FATAL,
    1765             :                 (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
    1766             :                  errmsg("database files are incompatible with server"),
    1767             :                  errdetail("The data directory was initialized by PostgreSQL version %s, "
    1768             :                            "which is not compatible with this version %s.",
    1769             :                            file_version_string, my_version_string)));
    1770       35420 : }
    1771             : 
    1772             : /*-------------------------------------------------------------------------
    1773             :  *              Library preload support
    1774             :  *-------------------------------------------------------------------------
    1775             :  */
    1776             : 
    1777             : /*
    1778             :  * GUC variables: lists of library names to be preloaded at postmaster
    1779             :  * start and at backend start
    1780             :  */
    1781             : char       *session_preload_libraries_string = NULL;
    1782             : char       *shared_preload_libraries_string = NULL;
    1783             : char       *local_preload_libraries_string = NULL;
    1784             : 
    1785             : /* Flag telling that we are loading shared_preload_libraries */
    1786             : bool        process_shared_preload_libraries_in_progress = false;
    1787             : bool        process_shared_preload_libraries_done = false;
    1788             : 
    1789             : shmem_request_hook_type shmem_request_hook = NULL;
    1790             : bool        process_shmem_requests_in_progress = false;
    1791             : 
    1792             : /*
    1793             :  * load the shared libraries listed in 'libraries'
    1794             :  *
    1795             :  * 'gucname': name of GUC variable, for error reports
    1796             :  * 'restricted': if true, force libraries to be in $libdir/plugins/
    1797             :  */
    1798             : static void
    1799       49422 : load_libraries(const char *libraries, const char *gucname, bool restricted)
    1800             : {
    1801             :     char       *rawstring;
    1802             :     List       *elemlist;
    1803             :     ListCell   *l;
    1804             : 
    1805       49422 :     if (libraries == NULL || libraries[0] == '\0')
    1806       49342 :         return;                 /* nothing to do */
    1807             : 
    1808             :     /* Need a modifiable copy of string */
    1809          80 :     rawstring = pstrdup(libraries);
    1810             : 
    1811             :     /* Parse string into list of filename paths */
    1812          80 :     if (!SplitDirectoriesString(rawstring, ',', &elemlist))
    1813             :     {
    1814             :         /* syntax error in list */
    1815           0 :         list_free_deep(elemlist);
    1816           0 :         pfree(rawstring);
    1817           0 :         ereport(LOG,
    1818             :                 (errcode(ERRCODE_SYNTAX_ERROR),
    1819             :                  errmsg("invalid list syntax in parameter \"%s\"",
    1820             :                         gucname)));
    1821           0 :         return;
    1822             :     }
    1823             : 
    1824         162 :     foreach(l, elemlist)
    1825             :     {
    1826             :         /* Note that filename was already canonicalized */
    1827          82 :         char       *filename = (char *) lfirst(l);
    1828          82 :         char       *expanded = NULL;
    1829             : 
    1830             :         /* If restricting, insert $libdir/plugins if not mentioned already */
    1831          82 :         if (restricted && first_dir_separator(filename) == NULL)
    1832             :         {
    1833           0 :             expanded = psprintf("$libdir/plugins/%s", filename);
    1834           0 :             filename = expanded;
    1835             :         }
    1836          82 :         load_file(filename, restricted);
    1837          82 :         ereport(DEBUG1,
    1838             :                 (errmsg_internal("loaded library \"%s\"", filename)));
    1839          82 :         if (expanded)
    1840           0 :             pfree(expanded);
    1841             :     }
    1842             : 
    1843          80 :     list_free_deep(elemlist);
    1844          80 :     pfree(rawstring);
    1845             : }
    1846             : 
    1847             : /*
    1848             :  * process any libraries that should be preloaded at postmaster start
    1849             :  */
    1850             : void
    1851        1886 : process_shared_preload_libraries(void)
    1852             : {
    1853        1886 :     process_shared_preload_libraries_in_progress = true;
    1854        1886 :     load_libraries(shared_preload_libraries_string,
    1855             :                    "shared_preload_libraries",
    1856             :                    false);
    1857        1886 :     process_shared_preload_libraries_in_progress = false;
    1858        1886 :     process_shared_preload_libraries_done = true;
    1859        1886 : }
    1860             : 
    1861             : /*
    1862             :  * process any libraries that should be preloaded at backend start
    1863             :  */
    1864             : void
    1865       23768 : process_session_preload_libraries(void)
    1866             : {
    1867       23768 :     load_libraries(session_preload_libraries_string,
    1868             :                    "session_preload_libraries",
    1869             :                    false);
    1870       23768 :     load_libraries(local_preload_libraries_string,
    1871             :                    "local_preload_libraries",
    1872             :                    true);
    1873       23768 : }
    1874             : 
    1875             : /*
    1876             :  * process any shared memory requests from preloaded libraries
    1877             :  */
    1878             : void
    1879        1876 : process_shmem_requests(void)
    1880             : {
    1881        1876 :     process_shmem_requests_in_progress = true;
    1882        1876 :     if (shmem_request_hook)
    1883          32 :         shmem_request_hook();
    1884        1876 :     process_shmem_requests_in_progress = false;
    1885        1876 : }
    1886             : 
    1887             : void
    1888        3650 : pg_bindtextdomain(const char *domain)
    1889             : {
    1890             : #ifdef ENABLE_NLS
    1891        3650 :     if (my_exec_path[0] != '\0')
    1892             :     {
    1893             :         char        locale_path[MAXPGPATH];
    1894             : 
    1895        3650 :         get_locale_path(my_exec_path, locale_path);
    1896        3650 :         bindtextdomain(domain, locale_path);
    1897        3650 :         pg_bind_textdomain_codeset(domain);
    1898             :     }
    1899             : #endif
    1900        3650 : }

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