LCOV - code coverage report
Current view: top level - src/backend/libpq - pqcomm.c (source / functions) Hit Total Coverage
Test: PostgreSQL 19devel Lines: 341 551 61.9 %
Date: 2025-08-17 01:17:32 Functions: 43 47 91.5 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * pqcomm.c
       4             :  *    Communication functions between the Frontend and the Backend
       5             :  *
       6             :  * These routines handle the low-level details of communication between
       7             :  * frontend and backend.  They just shove data across the communication
       8             :  * channel, and are ignorant of the semantics of the data.
       9             :  *
      10             :  * To emit an outgoing message, use the routines in pqformat.c to construct
      11             :  * the message in a buffer and then emit it in one call to pq_putmessage.
      12             :  * There are no functions to send raw bytes or partial messages; this
      13             :  * ensures that the channel will not be clogged by an incomplete message if
      14             :  * execution is aborted by ereport(ERROR) partway through the message.
      15             :  *
      16             :  * At one time, libpq was shared between frontend and backend, but now
      17             :  * the backend's "backend/libpq" is quite separate from "interfaces/libpq".
      18             :  * All that remains is similarities of names to trap the unwary...
      19             :  *
      20             :  * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
      21             :  * Portions Copyright (c) 1994, Regents of the University of California
      22             :  *
      23             :  *  src/backend/libpq/pqcomm.c
      24             :  *
      25             :  *-------------------------------------------------------------------------
      26             :  */
      27             : 
      28             : /*------------------------
      29             :  * INTERFACE ROUTINES
      30             :  *
      31             :  * setup/teardown:
      32             :  *      ListenServerPort    - Open postmaster's server port
      33             :  *      AcceptConnection    - Accept new connection with client
      34             :  *      TouchSocketFiles    - Protect socket files against /tmp cleaners
      35             :  *      pq_init             - initialize libpq at backend startup
      36             :  *      socket_comm_reset   - reset libpq during error recovery
      37             :  *      socket_close        - shutdown libpq at backend exit
      38             :  *
      39             :  * low-level I/O:
      40             :  *      pq_getbytes     - get a known number of bytes from connection
      41             :  *      pq_getmessage   - get a message with length word from connection
      42             :  *      pq_getbyte      - get next byte from connection
      43             :  *      pq_peekbyte     - peek at next byte from connection
      44             :  *      pq_flush        - flush pending output
      45             :  *      pq_flush_if_writable - flush pending output if writable without blocking
      46             :  *      pq_getbyte_if_available - get a byte if available without blocking
      47             :  *
      48             :  * message-level I/O
      49             :  *      pq_putmessage   - send a normal message (suppressed in COPY OUT mode)
      50             :  *      pq_putmessage_noblock - buffer a normal message (suppressed in COPY OUT)
      51             :  *
      52             :  *------------------------
      53             :  */
      54             : #include "postgres.h"
      55             : 
      56             : #ifdef HAVE_POLL_H
      57             : #include <poll.h>
      58             : #endif
      59             : #include <signal.h>
      60             : #include <fcntl.h>
      61             : #include <grp.h>
      62             : #include <unistd.h>
      63             : #include <sys/file.h>
      64             : #include <sys/socket.h>
      65             : #include <sys/stat.h>
      66             : #include <sys/time.h>
      67             : #include <netdb.h>
      68             : #include <netinet/in.h>
      69             : #include <netinet/tcp.h>
      70             : #include <utime.h>
      71             : #ifdef WIN32
      72             : #include <mstcpip.h>
      73             : #endif
      74             : 
      75             : #include "common/ip.h"
      76             : #include "libpq/libpq.h"
      77             : #include "miscadmin.h"
      78             : #include "port/pg_bswap.h"
      79             : #include "postmaster/postmaster.h"
      80             : #include "storage/ipc.h"
      81             : #include "utils/guc_hooks.h"
      82             : #include "utils/memutils.h"
      83             : 
      84             : /*
      85             :  * Cope with the various platform-specific ways to spell TCP keepalive socket
      86             :  * options.  This doesn't cover Windows, which as usual does its own thing.
      87             :  */
      88             : #if defined(TCP_KEEPIDLE)
      89             : /* TCP_KEEPIDLE is the name of this option on Linux and *BSD */
      90             : #define PG_TCP_KEEPALIVE_IDLE TCP_KEEPIDLE
      91             : #define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPIDLE"
      92             : #elif defined(TCP_KEEPALIVE_THRESHOLD)
      93             : /* TCP_KEEPALIVE_THRESHOLD is the name of this option on Solaris >= 11 */
      94             : #define PG_TCP_KEEPALIVE_IDLE TCP_KEEPALIVE_THRESHOLD
      95             : #define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPALIVE_THRESHOLD"
      96             : #elif defined(TCP_KEEPALIVE) && defined(__darwin__)
      97             : /* TCP_KEEPALIVE is the name of this option on macOS */
      98             : /* Caution: Solaris has this symbol but it means something different */
      99             : #define PG_TCP_KEEPALIVE_IDLE TCP_KEEPALIVE
     100             : #define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPALIVE"
     101             : #endif
     102             : 
     103             : /*
     104             :  * Configuration options
     105             :  */
     106             : int         Unix_socket_permissions;
     107             : char       *Unix_socket_group;
     108             : 
     109             : /* Where the Unix socket files are (list of palloc'd strings) */
     110             : static List *sock_paths = NIL;
     111             : 
     112             : /*
     113             :  * Buffers for low-level I/O.
     114             :  *
     115             :  * The receive buffer is fixed size. Send buffer is usually 8k, but can be
     116             :  * enlarged by pq_putmessage_noblock() if the message doesn't fit otherwise.
     117             :  */
     118             : 
     119             : #define PQ_SEND_BUFFER_SIZE 8192
     120             : #define PQ_RECV_BUFFER_SIZE 8192
     121             : 
     122             : static char *PqSendBuffer;
     123             : static int  PqSendBufferSize;   /* Size send buffer */
     124             : static size_t PqSendPointer;    /* Next index to store a byte in PqSendBuffer */
     125             : static size_t PqSendStart;      /* Next index to send a byte in PqSendBuffer */
     126             : 
     127             : static char PqRecvBuffer[PQ_RECV_BUFFER_SIZE];
     128             : static int  PqRecvPointer;      /* Next index to read a byte from PqRecvBuffer */
     129             : static int  PqRecvLength;       /* End of data available in PqRecvBuffer */
     130             : 
     131             : /*
     132             :  * Message status
     133             :  */
     134             : static bool PqCommBusy;         /* busy sending data to the client */
     135             : static bool PqCommReadingMsg;   /* in the middle of reading a message */
     136             : 
     137             : 
     138             : /* Internal functions */
     139             : static void socket_comm_reset(void);
     140             : static void socket_close(int code, Datum arg);
     141             : static void socket_set_nonblocking(bool nonblocking);
     142             : static int  socket_flush(void);
     143             : static int  socket_flush_if_writable(void);
     144             : static bool socket_is_send_pending(void);
     145             : static int  socket_putmessage(char msgtype, const char *s, size_t len);
     146             : static void socket_putmessage_noblock(char msgtype, const char *s, size_t len);
     147             : static inline int internal_putbytes(const void *b, size_t len);
     148             : static inline int internal_flush(void);
     149             : static pg_noinline int internal_flush_buffer(const char *buf, size_t *start,
     150             :                                              size_t *end);
     151             : 
     152             : static int  Lock_AF_UNIX(const char *unixSocketDir, const char *unixSocketPath);
     153             : static int  Setup_AF_UNIX(const char *sock_path);
     154             : 
     155             : static const PQcommMethods PqCommSocketMethods = {
     156             :     .comm_reset = socket_comm_reset,
     157             :     .flush = socket_flush,
     158             :     .flush_if_writable = socket_flush_if_writable,
     159             :     .is_send_pending = socket_is_send_pending,
     160             :     .putmessage = socket_putmessage,
     161             :     .putmessage_noblock = socket_putmessage_noblock
     162             : };
     163             : 
     164             : const PQcommMethods *PqCommMethods = &PqCommSocketMethods;
     165             : 
     166             : WaitEventSet *FeBeWaitSet;
     167             : 
     168             : 
     169             : /* --------------------------------
     170             :  *      pq_init - initialize libpq at backend startup
     171             :  * --------------------------------
     172             :  */
     173             : Port *
     174       25980 : pq_init(ClientSocket *client_sock)
     175             : {
     176             :     Port       *port;
     177             :     int         socket_pos PG_USED_FOR_ASSERTS_ONLY;
     178             :     int         latch_pos PG_USED_FOR_ASSERTS_ONLY;
     179             : 
     180             :     /* allocate the Port struct and copy the ClientSocket contents to it */
     181       25980 :     port = palloc0(sizeof(Port));
     182       25980 :     port->sock = client_sock->sock;
     183       25980 :     memcpy(&port->raddr.addr, &client_sock->raddr.addr, client_sock->raddr.salen);
     184       25980 :     port->raddr.salen = client_sock->raddr.salen;
     185             : 
     186             :     /* fill in the server (local) address */
     187       25980 :     port->laddr.salen = sizeof(port->laddr.addr);
     188       25980 :     if (getsockname(port->sock,
     189       25980 :                     (struct sockaddr *) &port->laddr.addr,
     190             :                     &port->laddr.salen) < 0)
     191             :     {
     192           0 :         ereport(FATAL,
     193             :                 (errmsg("%s() failed: %m", "getsockname")));
     194             :     }
     195             : 
     196             :     /* select NODELAY and KEEPALIVE options if it's a TCP connection */
     197       25980 :     if (port->laddr.addr.ss_family != AF_UNIX)
     198             :     {
     199             :         int         on;
     200             : #ifdef WIN32
     201             :         int         oldopt;
     202             :         int         optlen;
     203             :         int         newopt;
     204             : #endif
     205             : 
     206             : #ifdef  TCP_NODELAY
     207         578 :         on = 1;
     208         578 :         if (setsockopt(port->sock, IPPROTO_TCP, TCP_NODELAY,
     209             :                        (char *) &on, sizeof(on)) < 0)
     210             :         {
     211           0 :             ereport(FATAL,
     212             :                     (errmsg("%s(%s) failed: %m", "setsockopt", "TCP_NODELAY")));
     213             :         }
     214             : #endif
     215         578 :         on = 1;
     216         578 :         if (setsockopt(port->sock, SOL_SOCKET, SO_KEEPALIVE,
     217             :                        (char *) &on, sizeof(on)) < 0)
     218             :         {
     219           0 :             ereport(FATAL,
     220             :                     (errmsg("%s(%s) failed: %m", "setsockopt", "SO_KEEPALIVE")));
     221             :         }
     222             : 
     223             : #ifdef WIN32
     224             : 
     225             :         /*
     226             :          * This is a Win32 socket optimization.  The OS send buffer should be
     227             :          * large enough to send the whole Postgres send buffer in one go, or
     228             :          * performance suffers.  The Postgres send buffer can be enlarged if a
     229             :          * very large message needs to be sent, but we won't attempt to
     230             :          * enlarge the OS buffer if that happens, so somewhat arbitrarily
     231             :          * ensure that the OS buffer is at least PQ_SEND_BUFFER_SIZE * 4.
     232             :          * (That's 32kB with the current default).
     233             :          *
     234             :          * The default OS buffer size used to be 8kB in earlier Windows
     235             :          * versions, but was raised to 64kB in Windows 2012.  So it shouldn't
     236             :          * be necessary to change it in later versions anymore.  Changing it
     237             :          * unnecessarily can even reduce performance, because setting
     238             :          * SO_SNDBUF in the application disables the "dynamic send buffering"
     239             :          * feature that was introduced in Windows 7.  So before fiddling with
     240             :          * SO_SNDBUF, check if the current buffer size is already large enough
     241             :          * and only increase it if necessary.
     242             :          *
     243             :          * See https://support.microsoft.com/kb/823764/EN-US/ and
     244             :          * https://msdn.microsoft.com/en-us/library/bb736549%28v=vs.85%29.aspx
     245             :          */
     246             :         optlen = sizeof(oldopt);
     247             :         if (getsockopt(port->sock, SOL_SOCKET, SO_SNDBUF, (char *) &oldopt,
     248             :                        &optlen) < 0)
     249             :         {
     250             :             ereport(FATAL,
     251             :                     (errmsg("%s(%s) failed: %m", "getsockopt", "SO_SNDBUF")));
     252             :         }
     253             :         newopt = PQ_SEND_BUFFER_SIZE * 4;
     254             :         if (oldopt < newopt)
     255             :         {
     256             :             if (setsockopt(port->sock, SOL_SOCKET, SO_SNDBUF, (char *) &newopt,
     257             :                            sizeof(newopt)) < 0)
     258             :             {
     259             :                 ereport(FATAL,
     260             :                         (errmsg("%s(%s) failed: %m", "setsockopt", "SO_SNDBUF")));
     261             :             }
     262             :         }
     263             : #endif
     264             : 
     265             :         /*
     266             :          * Also apply the current keepalive parameters.  If we fail to set a
     267             :          * parameter, don't error out, because these aren't universally
     268             :          * supported.  (Note: you might think we need to reset the GUC
     269             :          * variables to 0 in such a case, but it's not necessary because the
     270             :          * show hooks for these variables report the truth anyway.)
     271             :          */
     272         578 :         (void) pq_setkeepalivesidle(tcp_keepalives_idle, port);
     273         578 :         (void) pq_setkeepalivesinterval(tcp_keepalives_interval, port);
     274         578 :         (void) pq_setkeepalivescount(tcp_keepalives_count, port);
     275         578 :         (void) pq_settcpusertimeout(tcp_user_timeout, port);
     276             :     }
     277             : 
     278             :     /* initialize state variables */
     279       25980 :     PqSendBufferSize = PQ_SEND_BUFFER_SIZE;
     280       25980 :     PqSendBuffer = MemoryContextAlloc(TopMemoryContext, PqSendBufferSize);
     281       25980 :     PqSendPointer = PqSendStart = PqRecvPointer = PqRecvLength = 0;
     282       25980 :     PqCommBusy = false;
     283       25980 :     PqCommReadingMsg = false;
     284             : 
     285             :     /* set up process-exit hook to close the socket */
     286       25980 :     on_proc_exit(socket_close, 0);
     287             : 
     288             :     /*
     289             :      * In backends (as soon as forked) we operate the underlying socket in
     290             :      * nonblocking mode and use latches to implement blocking semantics if
     291             :      * needed. That allows us to provide safely interruptible reads and
     292             :      * writes.
     293             :      */
     294             : #ifndef WIN32
     295       25980 :     if (!pg_set_noblock(port->sock))
     296           0 :         ereport(FATAL,
     297             :                 (errmsg("could not set socket to nonblocking mode: %m")));
     298             : #endif
     299             : 
     300             : #ifndef WIN32
     301             : 
     302             :     /* Don't give the socket to any subprograms we execute. */
     303       25980 :     if (fcntl(port->sock, F_SETFD, FD_CLOEXEC) < 0)
     304           0 :         elog(FATAL, "fcntl(F_SETFD) failed on socket: %m");
     305             : #endif
     306             : 
     307       25980 :     FeBeWaitSet = CreateWaitEventSet(NULL, FeBeWaitSetNEvents);
     308       25980 :     socket_pos = AddWaitEventToSet(FeBeWaitSet, WL_SOCKET_WRITEABLE,
     309             :                                    port->sock, NULL, NULL);
     310       25980 :     latch_pos = AddWaitEventToSet(FeBeWaitSet, WL_LATCH_SET, PGINVALID_SOCKET,
     311             :                                   MyLatch, NULL);
     312       25980 :     AddWaitEventToSet(FeBeWaitSet, WL_POSTMASTER_DEATH, PGINVALID_SOCKET,
     313             :                       NULL, NULL);
     314             : 
     315             :     /*
     316             :      * The event positions match the order we added them, but let's sanity
     317             :      * check them to be sure.
     318             :      */
     319             :     Assert(socket_pos == FeBeWaitSetSocketPos);
     320             :     Assert(latch_pos == FeBeWaitSetLatchPos);
     321             : 
     322       25980 :     return port;
     323             : }
     324             : 
     325             : /* --------------------------------
     326             :  *      socket_comm_reset - reset libpq during error recovery
     327             :  *
     328             :  * This is called from error recovery at the outer idle loop.  It's
     329             :  * just to get us out of trouble if we somehow manage to elog() from
     330             :  * inside a pqcomm.c routine (which ideally will never happen, but...)
     331             :  * --------------------------------
     332             :  */
     333             : static void
     334       43460 : socket_comm_reset(void)
     335             : {
     336             :     /* Do not throw away pending data, but do reset the busy flag */
     337       43460 :     PqCommBusy = false;
     338       43460 : }
     339             : 
     340             : /* --------------------------------
     341             :  *      socket_close - shutdown libpq at backend exit
     342             :  *
     343             :  * This is the one pg_on_exit_callback in place during BackendInitialize().
     344             :  * That function's unusual signal handling constrains that this callback be
     345             :  * safe to run at any instant.
     346             :  * --------------------------------
     347             :  */
     348             : static void
     349       25980 : socket_close(int code, Datum arg)
     350             : {
     351             :     /* Nothing to do in a standalone backend, where MyProcPort is NULL. */
     352       25980 :     if (MyProcPort != NULL)
     353             :     {
     354             : #ifdef ENABLE_GSS
     355             :         /*
     356             :          * Shutdown GSSAPI layer.  This section does nothing when interrupting
     357             :          * BackendInitialize(), because pg_GSS_recvauth() makes first use of
     358             :          * "ctx" and "cred".
     359             :          *
     360             :          * Note that we don't bother to free MyProcPort->gss, since we're
     361             :          * about to exit anyway.
     362             :          */
     363             :         if (MyProcPort->gss)
     364             :         {
     365             :             OM_uint32   min_s;
     366             : 
     367             :             if (MyProcPort->gss->ctx != GSS_C_NO_CONTEXT)
     368             :                 gss_delete_sec_context(&min_s, &MyProcPort->gss->ctx, NULL);
     369             : 
     370             :             if (MyProcPort->gss->cred != GSS_C_NO_CREDENTIAL)
     371             :                 gss_release_cred(&min_s, &MyProcPort->gss->cred);
     372             :         }
     373             : #endif                          /* ENABLE_GSS */
     374             : 
     375             :         /*
     376             :          * Cleanly shut down SSL layer.  Nowhere else does a postmaster child
     377             :          * call this, so this is safe when interrupting BackendInitialize().
     378             :          */
     379       25980 :         secure_close(MyProcPort);
     380             : 
     381             :         /*
     382             :          * Formerly we did an explicit close() here, but it seems better to
     383             :          * leave the socket open until the process dies.  This allows clients
     384             :          * to perform a "synchronous close" if they care --- wait till the
     385             :          * transport layer reports connection closure, and you can be sure the
     386             :          * backend has exited.
     387             :          *
     388             :          * We do set sock to PGINVALID_SOCKET to prevent any further I/O,
     389             :          * though.
     390             :          */
     391       25980 :         MyProcPort->sock = PGINVALID_SOCKET;
     392             :     }
     393       25980 : }
     394             : 
     395             : 
     396             : 
     397             : /* --------------------------------
     398             :  * Postmaster functions to handle sockets.
     399             :  * --------------------------------
     400             :  */
     401             : 
     402             : /*
     403             :  * ListenServerPort -- open a "listening" port to accept connections.
     404             :  *
     405             :  * family should be AF_UNIX or AF_UNSPEC; portNumber is the port number.
     406             :  * For AF_UNIX ports, hostName should be NULL and unixSocketDir must be
     407             :  * specified.  For TCP ports, hostName is either NULL for all interfaces or
     408             :  * the interface to listen on, and unixSocketDir is ignored (can be NULL).
     409             :  *
     410             :  * Successfully opened sockets are appended to the ListenSockets[] array.  On
     411             :  * entry, *NumListenSockets holds the number of elements currently in the
     412             :  * array, and it is updated to reflect the opened sockets.  MaxListen is the
     413             :  * allocated size of the array.
     414             :  *
     415             :  * RETURNS: STATUS_OK or STATUS_ERROR
     416             :  */
     417             : int
     418        1756 : ListenServerPort(int family, const char *hostName, unsigned short portNumber,
     419             :                  const char *unixSocketDir,
     420             :                  pgsocket ListenSockets[], int *NumListenSockets, int MaxListen)
     421             : {
     422             :     pgsocket    fd;
     423             :     int         err;
     424             :     int         maxconn;
     425             :     int         ret;
     426             :     char        portNumberStr[32];
     427             :     const char *familyDesc;
     428             :     char        familyDescBuf[64];
     429             :     const char *addrDesc;
     430             :     char        addrBuf[NI_MAXHOST];
     431             :     char       *service;
     432        1756 :     struct addrinfo *addrs = NULL,
     433             :                *addr;
     434             :     struct addrinfo hint;
     435        1756 :     int         added = 0;
     436             :     char        unixSocketPath[MAXPGPATH];
     437             : #if !defined(WIN32) || defined(IPV6_V6ONLY)
     438        1756 :     int         one = 1;
     439             : #endif
     440             : 
     441             :     /* Initialize hint structure */
     442       12292 :     MemSet(&hint, 0, sizeof(hint));
     443        1756 :     hint.ai_family = family;
     444        1756 :     hint.ai_flags = AI_PASSIVE;
     445        1756 :     hint.ai_socktype = SOCK_STREAM;
     446             : 
     447        1756 :     if (family == AF_UNIX)
     448             :     {
     449             :         /*
     450             :          * Create unixSocketPath from portNumber and unixSocketDir and lock
     451             :          * that file path
     452             :          */
     453        1698 :         UNIXSOCK_PATH(unixSocketPath, portNumber, unixSocketDir);
     454        1698 :         if (strlen(unixSocketPath) >= UNIXSOCK_PATH_BUFLEN)
     455             :         {
     456           0 :             ereport(LOG,
     457             :                     (errmsg("Unix-domain socket path \"%s\" is too long (maximum %d bytes)",
     458             :                             unixSocketPath,
     459             :                             (int) (UNIXSOCK_PATH_BUFLEN - 1))));
     460           0 :             return STATUS_ERROR;
     461             :         }
     462        1698 :         if (Lock_AF_UNIX(unixSocketDir, unixSocketPath) != STATUS_OK)
     463           0 :             return STATUS_ERROR;
     464        1698 :         service = unixSocketPath;
     465             :     }
     466             :     else
     467             :     {
     468          58 :         snprintf(portNumberStr, sizeof(portNumberStr), "%d", portNumber);
     469          58 :         service = portNumberStr;
     470             :     }
     471             : 
     472        1756 :     ret = pg_getaddrinfo_all(hostName, service, &hint, &addrs);
     473        1756 :     if (ret || !addrs)
     474             :     {
     475           0 :         if (hostName)
     476           0 :             ereport(LOG,
     477             :                     (errmsg("could not translate host name \"%s\", service \"%s\" to address: %s",
     478             :                             hostName, service, gai_strerror(ret))));
     479             :         else
     480           0 :             ereport(LOG,
     481             :                     (errmsg("could not translate service \"%s\" to address: %s",
     482             :                             service, gai_strerror(ret))));
     483           0 :         if (addrs)
     484           0 :             pg_freeaddrinfo_all(hint.ai_family, addrs);
     485           0 :         return STATUS_ERROR;
     486             :     }
     487             : 
     488        3514 :     for (addr = addrs; addr; addr = addr->ai_next)
     489             :     {
     490        1758 :         if (family != AF_UNIX && addr->ai_family == AF_UNIX)
     491             :         {
     492             :             /*
     493             :              * Only set up a unix domain socket when they really asked for it.
     494             :              * The service/port is different in that case.
     495             :              */
     496           0 :             continue;
     497             :         }
     498             : 
     499             :         /* See if there is still room to add 1 more socket. */
     500        1758 :         if (*NumListenSockets == MaxListen)
     501             :         {
     502           0 :             ereport(LOG,
     503             :                     (errmsg("could not bind to all requested addresses: MAXLISTEN (%d) exceeded",
     504             :                             MaxListen)));
     505           0 :             break;
     506             :         }
     507             : 
     508             :         /* set up address family name for log messages */
     509        1758 :         switch (addr->ai_family)
     510             :         {
     511          58 :             case AF_INET:
     512          58 :                 familyDesc = _("IPv4");
     513          58 :                 break;
     514           2 :             case AF_INET6:
     515           2 :                 familyDesc = _("IPv6");
     516           2 :                 break;
     517        1698 :             case AF_UNIX:
     518        1698 :                 familyDesc = _("Unix");
     519        1698 :                 break;
     520           0 :             default:
     521           0 :                 snprintf(familyDescBuf, sizeof(familyDescBuf),
     522           0 :                          _("unrecognized address family %d"),
     523             :                          addr->ai_family);
     524           0 :                 familyDesc = familyDescBuf;
     525           0 :                 break;
     526             :         }
     527             : 
     528             :         /* set up text form of address for log messages */
     529        1758 :         if (addr->ai_family == AF_UNIX)
     530        1698 :             addrDesc = unixSocketPath;
     531             :         else
     532             :         {
     533          60 :             pg_getnameinfo_all((const struct sockaddr_storage *) addr->ai_addr,
     534          60 :                                addr->ai_addrlen,
     535             :                                addrBuf, sizeof(addrBuf),
     536             :                                NULL, 0,
     537             :                                NI_NUMERICHOST);
     538          60 :             addrDesc = addrBuf;
     539             :         }
     540             : 
     541        1758 :         if ((fd = socket(addr->ai_family, SOCK_STREAM, 0)) == PGINVALID_SOCKET)
     542             :         {
     543           0 :             ereport(LOG,
     544             :                     (errcode_for_socket_access(),
     545             :             /* translator: first %s is IPv4, IPv6, or Unix */
     546             :                      errmsg("could not create %s socket for address \"%s\": %m",
     547             :                             familyDesc, addrDesc)));
     548           0 :             continue;
     549             :         }
     550             : 
     551             : #ifndef WIN32
     552             :         /* Don't give the listen socket to any subprograms we execute. */
     553        1758 :         if (fcntl(fd, F_SETFD, FD_CLOEXEC) < 0)
     554           0 :             elog(FATAL, "fcntl(F_SETFD) failed on socket: %m");
     555             : 
     556             :         /*
     557             :          * Without the SO_REUSEADDR flag, a new postmaster can't be started
     558             :          * right away after a stop or crash, giving "address already in use"
     559             :          * error on TCP ports.
     560             :          *
     561             :          * On win32, however, this behavior only happens if the
     562             :          * SO_EXCLUSIVEADDRUSE is set. With SO_REUSEADDR, win32 allows
     563             :          * multiple servers to listen on the same address, resulting in
     564             :          * unpredictable behavior. With no flags at all, win32 behaves as Unix
     565             :          * with SO_REUSEADDR.
     566             :          */
     567        1758 :         if (addr->ai_family != AF_UNIX)
     568             :         {
     569          60 :             if ((setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
     570             :                             (char *) &one, sizeof(one))) == -1)
     571             :             {
     572           0 :                 ereport(LOG,
     573             :                         (errcode_for_socket_access(),
     574             :                 /* translator: third %s is IPv4 or IPv6 */
     575             :                          errmsg("%s(%s) failed for %s address \"%s\": %m",
     576             :                                 "setsockopt", "SO_REUSEADDR",
     577             :                                 familyDesc, addrDesc)));
     578           0 :                 closesocket(fd);
     579           0 :                 continue;
     580             :             }
     581             :         }
     582             : #endif
     583             : 
     584             : #ifdef IPV6_V6ONLY
     585        1758 :         if (addr->ai_family == AF_INET6)
     586             :         {
     587           2 :             if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY,
     588             :                            (char *) &one, sizeof(one)) == -1)
     589             :             {
     590           0 :                 ereport(LOG,
     591             :                         (errcode_for_socket_access(),
     592             :                 /* translator: third %s is IPv6 */
     593             :                          errmsg("%s(%s) failed for %s address \"%s\": %m",
     594             :                                 "setsockopt", "IPV6_V6ONLY",
     595             :                                 familyDesc, addrDesc)));
     596           0 :                 closesocket(fd);
     597           0 :                 continue;
     598             :             }
     599             :         }
     600             : #endif
     601             : 
     602             :         /*
     603             :          * Note: This might fail on some OS's, like Linux older than
     604             :          * 2.4.21-pre3, that don't have the IPV6_V6ONLY socket option, and map
     605             :          * ipv4 addresses to ipv6.  It will show ::ffff:ipv4 for all ipv4
     606             :          * connections.
     607             :          */
     608        1758 :         err = bind(fd, addr->ai_addr, addr->ai_addrlen);
     609        1758 :         if (err < 0)
     610           0 :         {
     611           0 :             int         saved_errno = errno;
     612             : 
     613           0 :             ereport(LOG,
     614             :                     (errcode_for_socket_access(),
     615             :             /* translator: first %s is IPv4, IPv6, or Unix */
     616             :                      errmsg("could not bind %s address \"%s\": %m",
     617             :                             familyDesc, addrDesc),
     618             :                      saved_errno == EADDRINUSE ?
     619             :                      (addr->ai_family == AF_UNIX ?
     620             :                       errhint("Is another postmaster already running on port %d?",
     621             :                               (int) portNumber) :
     622             :                       errhint("Is another postmaster already running on port %d?"
     623             :                               " If not, wait a few seconds and retry.",
     624             :                               (int) portNumber)) : 0));
     625           0 :             closesocket(fd);
     626           0 :             continue;
     627             :         }
     628             : 
     629        1758 :         if (addr->ai_family == AF_UNIX)
     630             :         {
     631        1698 :             if (Setup_AF_UNIX(service) != STATUS_OK)
     632             :             {
     633           0 :                 closesocket(fd);
     634           0 :                 break;
     635             :             }
     636             :         }
     637             : 
     638             :         /*
     639             :          * Select appropriate accept-queue length limit.  It seems reasonable
     640             :          * to use a value similar to the maximum number of child processes
     641             :          * that the postmaster will permit.
     642             :          */
     643        1758 :         maxconn = MaxConnections * 2;
     644             : 
     645        1758 :         err = listen(fd, maxconn);
     646        1758 :         if (err < 0)
     647             :         {
     648           0 :             ereport(LOG,
     649             :                     (errcode_for_socket_access(),
     650             :             /* translator: first %s is IPv4, IPv6, or Unix */
     651             :                      errmsg("could not listen on %s address \"%s\": %m",
     652             :                             familyDesc, addrDesc)));
     653           0 :             closesocket(fd);
     654           0 :             continue;
     655             :         }
     656             : 
     657        1758 :         if (addr->ai_family == AF_UNIX)
     658        1698 :             ereport(LOG,
     659             :                     (errmsg("listening on Unix socket \"%s\"",
     660             :                             addrDesc)));
     661             :         else
     662          60 :             ereport(LOG,
     663             :             /* translator: first %s is IPv4 or IPv6 */
     664             :                     (errmsg("listening on %s address \"%s\", port %d",
     665             :                             familyDesc, addrDesc, (int) portNumber)));
     666             : 
     667        1758 :         ListenSockets[*NumListenSockets] = fd;
     668        1758 :         (*NumListenSockets)++;
     669        1758 :         added++;
     670             :     }
     671             : 
     672        1756 :     pg_freeaddrinfo_all(hint.ai_family, addrs);
     673             : 
     674        1756 :     if (!added)
     675           0 :         return STATUS_ERROR;
     676             : 
     677        1756 :     return STATUS_OK;
     678             : }
     679             : 
     680             : 
     681             : /*
     682             :  * Lock_AF_UNIX -- configure unix socket file path
     683             :  */
     684             : static int
     685        1698 : Lock_AF_UNIX(const char *unixSocketDir, const char *unixSocketPath)
     686             : {
     687             :     /* no lock file for abstract sockets */
     688        1698 :     if (unixSocketPath[0] == '@')
     689           0 :         return STATUS_OK;
     690             : 
     691             :     /*
     692             :      * Grab an interlock file associated with the socket file.
     693             :      *
     694             :      * Note: there are two reasons for using a socket lock file, rather than
     695             :      * trying to interlock directly on the socket itself.  First, it's a lot
     696             :      * more portable, and second, it lets us remove any pre-existing socket
     697             :      * file without race conditions.
     698             :      */
     699        1698 :     CreateSocketLockFile(unixSocketPath, true, unixSocketDir);
     700             : 
     701             :     /*
     702             :      * Once we have the interlock, we can safely delete any pre-existing
     703             :      * socket file to avoid failure at bind() time.
     704             :      */
     705        1698 :     (void) unlink(unixSocketPath);
     706             : 
     707             :     /*
     708             :      * Remember socket file pathnames for later maintenance.
     709             :      */
     710        1698 :     sock_paths = lappend(sock_paths, pstrdup(unixSocketPath));
     711             : 
     712        1698 :     return STATUS_OK;
     713             : }
     714             : 
     715             : 
     716             : /*
     717             :  * Setup_AF_UNIX -- configure unix socket permissions
     718             :  */
     719             : static int
     720        1698 : Setup_AF_UNIX(const char *sock_path)
     721             : {
     722             :     /* no file system permissions for abstract sockets */
     723        1698 :     if (sock_path[0] == '@')
     724           0 :         return STATUS_OK;
     725             : 
     726             :     /*
     727             :      * Fix socket ownership/permission if requested.  Note we must do this
     728             :      * before we listen() to avoid a window where unwanted connections could
     729             :      * get accepted.
     730             :      */
     731             :     Assert(Unix_socket_group);
     732        1698 :     if (Unix_socket_group[0] != '\0')
     733             :     {
     734             : #ifdef WIN32
     735             :         elog(WARNING, "configuration item \"unix_socket_group\" is not supported on this platform");
     736             : #else
     737             :         char       *endptr;
     738             :         unsigned long val;
     739             :         gid_t       gid;
     740             : 
     741           0 :         val = strtoul(Unix_socket_group, &endptr, 10);
     742           0 :         if (*endptr == '\0')
     743             :         {                       /* numeric group id */
     744           0 :             gid = val;
     745             :         }
     746             :         else
     747             :         {                       /* convert group name to id */
     748             :             struct group *gr;
     749             : 
     750           0 :             gr = getgrnam(Unix_socket_group);
     751           0 :             if (!gr)
     752             :             {
     753           0 :                 ereport(LOG,
     754             :                         (errmsg("group \"%s\" does not exist",
     755             :                                 Unix_socket_group)));
     756           0 :                 return STATUS_ERROR;
     757             :             }
     758           0 :             gid = gr->gr_gid;
     759             :         }
     760           0 :         if (chown(sock_path, -1, gid) == -1)
     761             :         {
     762           0 :             ereport(LOG,
     763             :                     (errcode_for_file_access(),
     764             :                      errmsg("could not set group of file \"%s\": %m",
     765             :                             sock_path)));
     766           0 :             return STATUS_ERROR;
     767             :         }
     768             : #endif
     769             :     }
     770             : 
     771        1698 :     if (chmod(sock_path, Unix_socket_permissions) == -1)
     772             :     {
     773           0 :         ereport(LOG,
     774             :                 (errcode_for_file_access(),
     775             :                  errmsg("could not set permissions of file \"%s\": %m",
     776             :                         sock_path)));
     777           0 :         return STATUS_ERROR;
     778             :     }
     779        1698 :     return STATUS_OK;
     780             : }
     781             : 
     782             : 
     783             : /*
     784             :  * AcceptConnection -- accept a new connection with client using
     785             :  *      server port.  Fills *client_sock with the FD and endpoint info
     786             :  *      of the new connection.
     787             :  *
     788             :  * ASSUME: that this doesn't need to be non-blocking because
     789             :  *      the Postmaster waits for the socket to be ready to accept().
     790             :  *
     791             :  * RETURNS: STATUS_OK or STATUS_ERROR
     792             :  */
     793             : int
     794       26706 : AcceptConnection(pgsocket server_fd, ClientSocket *client_sock)
     795             : {
     796             :     /* accept connection and fill in the client (remote) address */
     797       26706 :     client_sock->raddr.salen = sizeof(client_sock->raddr.addr);
     798       26706 :     if ((client_sock->sock = accept(server_fd,
     799       26706 :                                     (struct sockaddr *) &client_sock->raddr.addr,
     800             :                                     &client_sock->raddr.salen)) == PGINVALID_SOCKET)
     801             :     {
     802           0 :         ereport(LOG,
     803             :                 (errcode_for_socket_access(),
     804             :                  errmsg("could not accept new connection: %m")));
     805             : 
     806             :         /*
     807             :          * If accept() fails then postmaster.c will still see the server
     808             :          * socket as read-ready, and will immediately try again.  To avoid
     809             :          * uselessly sucking lots of CPU, delay a bit before trying again.
     810             :          * (The most likely reason for failure is being out of kernel file
     811             :          * table slots; we can do little except hope some will get freed up.)
     812             :          */
     813           0 :         pg_usleep(100000L);     /* wait 0.1 sec */
     814           0 :         return STATUS_ERROR;
     815             :     }
     816             : 
     817       26706 :     return STATUS_OK;
     818             : }
     819             : 
     820             : /*
     821             :  * TouchSocketFiles -- mark socket files as recently accessed
     822             :  *
     823             :  * This routine should be called every so often to ensure that the socket
     824             :  * files have a recent mod date (ordinary operations on sockets usually won't
     825             :  * change the mod date).  That saves them from being removed by
     826             :  * overenthusiastic /tmp-directory-cleaner daemons.  (Another reason we should
     827             :  * never have put the socket file in /tmp...)
     828             :  */
     829             : void
     830           0 : TouchSocketFiles(void)
     831             : {
     832             :     ListCell   *l;
     833             : 
     834             :     /* Loop through all created sockets... */
     835           0 :     foreach(l, sock_paths)
     836             :     {
     837           0 :         char       *sock_path = (char *) lfirst(l);
     838             : 
     839             :         /* Ignore errors; there's no point in complaining */
     840           0 :         (void) utime(sock_path, NULL);
     841             :     }
     842           0 : }
     843             : 
     844             : /*
     845             :  * RemoveSocketFiles -- unlink socket files at postmaster shutdown
     846             :  */
     847             : void
     848        1700 : RemoveSocketFiles(void)
     849             : {
     850             :     ListCell   *l;
     851             : 
     852             :     /* Loop through all created sockets... */
     853        3398 :     foreach(l, sock_paths)
     854             :     {
     855        1698 :         char       *sock_path = (char *) lfirst(l);
     856             : 
     857             :         /* Ignore any error. */
     858        1698 :         (void) unlink(sock_path);
     859             :     }
     860             :     /* Since we're about to exit, no need to reclaim storage */
     861        1700 : }
     862             : 
     863             : 
     864             : /* --------------------------------
     865             :  * Low-level I/O routines begin here.
     866             :  *
     867             :  * These routines communicate with a frontend client across a connection
     868             :  * already established by the preceding routines.
     869             :  * --------------------------------
     870             :  */
     871             : 
     872             : /* --------------------------------
     873             :  *            socket_set_nonblocking - set socket blocking/non-blocking
     874             :  *
     875             :  * Sets the socket non-blocking if nonblocking is true, or sets it
     876             :  * blocking otherwise.
     877             :  * --------------------------------
     878             :  */
     879             : static void
     880     6323910 : socket_set_nonblocking(bool nonblocking)
     881             : {
     882     6323910 :     if (MyProcPort == NULL)
     883           0 :         ereport(ERROR,
     884             :                 (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST),
     885             :                  errmsg("there is no client connection")));
     886             : 
     887     6323910 :     MyProcPort->noblock = nonblocking;
     888     6323910 : }
     889             : 
     890             : /* --------------------------------
     891             :  *      pq_recvbuf - load some bytes into the input buffer
     892             :  *
     893             :  *      returns 0 if OK, EOF if trouble
     894             :  * --------------------------------
     895             :  */
     896             : static int
     897      730522 : pq_recvbuf(void)
     898             : {
     899      730522 :     if (PqRecvPointer > 0)
     900             :     {
     901      704542 :         if (PqRecvLength > PqRecvPointer)
     902             :         {
     903             :             /* still some unread data, left-justify it in the buffer */
     904           0 :             memmove(PqRecvBuffer, PqRecvBuffer + PqRecvPointer,
     905           0 :                     PqRecvLength - PqRecvPointer);
     906           0 :             PqRecvLength -= PqRecvPointer;
     907           0 :             PqRecvPointer = 0;
     908             :         }
     909             :         else
     910      704542 :             PqRecvLength = PqRecvPointer = 0;
     911             :     }
     912             : 
     913             :     /* Ensure that we're in blocking mode */
     914      730522 :     socket_set_nonblocking(false);
     915             : 
     916             :     /* Can fill buffer from PqRecvLength and upwards */
     917             :     for (;;)
     918           0 :     {
     919             :         int         r;
     920             : 
     921      730522 :         errno = 0;
     922             : 
     923     1460968 :         r = secure_read(MyProcPort, PqRecvBuffer + PqRecvLength,
     924      730522 :                         PQ_RECV_BUFFER_SIZE - PqRecvLength);
     925             : 
     926      730446 :         if (r < 0)
     927             :         {
     928           2 :             if (errno == EINTR)
     929           0 :                 continue;       /* Ok if interrupted */
     930             : 
     931             :             /*
     932             :              * Careful: an ereport() that tries to write to the client would
     933             :              * cause recursion to here, leading to stack overflow and core
     934             :              * dump!  This message must go *only* to the postmaster log.
     935             :              *
     936             :              * If errno is zero, assume it's EOF and let the caller complain.
     937             :              */
     938           2 :             if (errno != 0)
     939           2 :                 ereport(COMMERROR,
     940             :                         (errcode_for_socket_access(),
     941             :                          errmsg("could not receive data from client: %m")));
     942           2 :             return EOF;
     943             :         }
     944      730444 :         if (r == 0)
     945             :         {
     946             :             /*
     947             :              * EOF detected.  We used to write a log message here, but it's
     948             :              * better to expect the ultimate caller to do that.
     949             :              */
     950         160 :             return EOF;
     951             :         }
     952             :         /* r contains number of bytes read, so just incr length */
     953      730284 :         PqRecvLength += r;
     954      730284 :         return 0;
     955             :     }
     956             : }
     957             : 
     958             : /* --------------------------------
     959             :  *      pq_getbyte  - get a single byte from connection, or return EOF
     960             :  * --------------------------------
     961             :  */
     962             : int
     963     1116096 : pq_getbyte(void)
     964             : {
     965             :     Assert(PqCommReadingMsg);
     966             : 
     967     1752076 :     while (PqRecvPointer >= PqRecvLength)
     968             :     {
     969      636184 :         if (pq_recvbuf())       /* If nothing in buffer, then recv some */
     970         128 :             return EOF;         /* Failed to recv data */
     971             :     }
     972     1115892 :     return (unsigned char) PqRecvBuffer[PqRecvPointer++];
     973             : }
     974             : 
     975             : /* --------------------------------
     976             :  *      pq_peekbyte     - peek at next byte from connection
     977             :  *
     978             :  *   Same as pq_getbyte() except we don't advance the pointer.
     979             :  * --------------------------------
     980             :  */
     981             : int
     982       25980 : pq_peekbyte(void)
     983             : {
     984             :     Assert(PqCommReadingMsg);
     985             : 
     986       51956 :     while (PqRecvPointer >= PqRecvLength)
     987             :     {
     988       25980 :         if (pq_recvbuf())       /* If nothing in buffer, then recv some */
     989           4 :             return EOF;         /* Failed to recv data */
     990             :     }
     991       25976 :     return (unsigned char) PqRecvBuffer[PqRecvPointer];
     992             : }
     993             : 
     994             : /* --------------------------------
     995             :  *      pq_getbyte_if_available - get a single byte from connection,
     996             :  *          if available
     997             :  *
     998             :  * The received byte is stored in *c. Returns 1 if a byte was read,
     999             :  * 0 if no data was available, or EOF if trouble.
    1000             :  * --------------------------------
    1001             :  */
    1002             : int
    1003     3606958 : pq_getbyte_if_available(unsigned char *c)
    1004             : {
    1005             :     int         r;
    1006             : 
    1007             :     Assert(PqCommReadingMsg);
    1008             : 
    1009     3606958 :     if (PqRecvPointer < PqRecvLength)
    1010             :     {
    1011      119458 :         *c = PqRecvBuffer[PqRecvPointer++];
    1012      119458 :         return 1;
    1013             :     }
    1014             : 
    1015             :     /* Put the socket into non-blocking mode */
    1016     3487500 :     socket_set_nonblocking(true);
    1017             : 
    1018     3487500 :     errno = 0;
    1019             : 
    1020     3487500 :     r = secure_read(MyProcPort, c, 1);
    1021     3487500 :     if (r < 0)
    1022             :     {
    1023             :         /*
    1024             :          * Ok if no data available without blocking or interrupted (though
    1025             :          * EINTR really shouldn't happen with a non-blocking socket). Report
    1026             :          * other errors.
    1027             :          */
    1028     3422158 :         if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR)
    1029     3422150 :             r = 0;
    1030             :         else
    1031             :         {
    1032             :             /*
    1033             :              * Careful: an ereport() that tries to write to the client would
    1034             :              * cause recursion to here, leading to stack overflow and core
    1035             :              * dump!  This message must go *only* to the postmaster log.
    1036             :              *
    1037             :              * If errno is zero, assume it's EOF and let the caller complain.
    1038             :              */
    1039           8 :             if (errno != 0)
    1040           8 :                 ereport(COMMERROR,
    1041             :                         (errcode_for_socket_access(),
    1042             :                          errmsg("could not receive data from client: %m")));
    1043           8 :             r = EOF;
    1044             :         }
    1045             :     }
    1046       65342 :     else if (r == 0)
    1047             :     {
    1048             :         /* EOF detected */
    1049          20 :         r = EOF;
    1050             :     }
    1051             : 
    1052     3487500 :     return r;
    1053             : }
    1054             : 
    1055             : /* --------------------------------
    1056             :  *      pq_getbytes     - get a known number of bytes from connection
    1057             :  *
    1058             :  *      returns 0 if OK, EOF if trouble
    1059             :  * --------------------------------
    1060             :  */
    1061             : int
    1062     2630878 : pq_getbytes(void *b, size_t len)
    1063             : {
    1064     2630878 :     char       *s = b;
    1065             :     size_t      amount;
    1066             : 
    1067             :     Assert(PqCommReadingMsg);
    1068             : 
    1069     5264240 :     while (len > 0)
    1070             :     {
    1071     2701720 :         while (PqRecvPointer >= PqRecvLength)
    1072             :         {
    1073       68358 :             if (pq_recvbuf())   /* If nothing in buffer, then recv some */
    1074          30 :                 return EOF;     /* Failed to recv data */
    1075             :         }
    1076     2633362 :         amount = PqRecvLength - PqRecvPointer;
    1077     2633362 :         if (amount > len)
    1078     1903204 :             amount = len;
    1079     2633362 :         memcpy(s, PqRecvBuffer + PqRecvPointer, amount);
    1080     2633362 :         PqRecvPointer += amount;
    1081     2633362 :         s += amount;
    1082     2633362 :         len -= amount;
    1083             :     }
    1084     2630848 :     return 0;
    1085             : }
    1086             : 
    1087             : /* --------------------------------
    1088             :  *      pq_discardbytes     - throw away a known number of bytes
    1089             :  *
    1090             :  *      same as pq_getbytes except we do not copy the data to anyplace.
    1091             :  *      this is used for resynchronizing after read errors.
    1092             :  *
    1093             :  *      returns 0 if OK, EOF if trouble
    1094             :  * --------------------------------
    1095             :  */
    1096             : static int
    1097           0 : pq_discardbytes(size_t len)
    1098             : {
    1099             :     size_t      amount;
    1100             : 
    1101             :     Assert(PqCommReadingMsg);
    1102             : 
    1103           0 :     while (len > 0)
    1104             :     {
    1105           0 :         while (PqRecvPointer >= PqRecvLength)
    1106             :         {
    1107           0 :             if (pq_recvbuf())   /* If nothing in buffer, then recv some */
    1108           0 :                 return EOF;     /* Failed to recv data */
    1109             :         }
    1110           0 :         amount = PqRecvLength - PqRecvPointer;
    1111           0 :         if (amount > len)
    1112           0 :             amount = len;
    1113           0 :         PqRecvPointer += amount;
    1114           0 :         len -= amount;
    1115             :     }
    1116           0 :     return 0;
    1117             : }
    1118             : 
    1119             : /* --------------------------------
    1120             :  *      pq_buffer_remaining_data    - return number of bytes in receive buffer
    1121             :  *
    1122             :  * This will *not* attempt to read more data. And reading up to that number of
    1123             :  * bytes should not cause reading any more data either.
    1124             :  * --------------------------------
    1125             :  */
    1126             : ssize_t
    1127         754 : pq_buffer_remaining_data(void)
    1128             : {
    1129             :     Assert(PqRecvLength >= PqRecvPointer);
    1130         754 :     return (PqRecvLength - PqRecvPointer);
    1131             : }
    1132             : 
    1133             : 
    1134             : /* --------------------------------
    1135             :  *      pq_startmsgread - begin reading a message from the client.
    1136             :  *
    1137             :  *      This must be called before any of the pq_get* functions.
    1138             :  * --------------------------------
    1139             :  */
    1140             : void
    1141     4775514 : pq_startmsgread(void)
    1142             : {
    1143             :     /*
    1144             :      * There shouldn't be a read active already, but let's check just to be
    1145             :      * sure.
    1146             :      */
    1147     4775514 :     if (PqCommReadingMsg)
    1148           0 :         ereport(FATAL,
    1149             :                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
    1150             :                  errmsg("terminating connection because protocol synchronization was lost")));
    1151             : 
    1152     4775514 :     PqCommReadingMsg = true;
    1153     4775514 : }
    1154             : 
    1155             : 
    1156             : /* --------------------------------
    1157             :  *      pq_endmsgread   - finish reading message.
    1158             :  *
    1159             :  *      This must be called after reading a message with pq_getbytes()
    1160             :  *      and friends, to indicate that we have read the whole message.
    1161             :  *      pq_getmessage() does this implicitly.
    1162             :  * --------------------------------
    1163             :  */
    1164             : void
    1165     3474580 : pq_endmsgread(void)
    1166             : {
    1167             :     Assert(PqCommReadingMsg);
    1168             : 
    1169     3474580 :     PqCommReadingMsg = false;
    1170     3474580 : }
    1171             : 
    1172             : /* --------------------------------
    1173             :  *      pq_is_reading_msg - are we currently reading a message?
    1174             :  *
    1175             :  * This is used in error recovery at the outer idle loop to detect if we have
    1176             :  * lost protocol sync, and need to terminate the connection. pq_startmsgread()
    1177             :  * will check for that too, but it's nicer to detect it earlier.
    1178             :  * --------------------------------
    1179             :  */
    1180             : bool
    1181       43460 : pq_is_reading_msg(void)
    1182             : {
    1183       43460 :     return PqCommReadingMsg;
    1184             : }
    1185             : 
    1186             : /* --------------------------------
    1187             :  *      pq_getmessage   - get a message with length word from connection
    1188             :  *
    1189             :  *      The return value is placed in an expansible StringInfo, which has
    1190             :  *      already been initialized by the caller.
    1191             :  *      Only the message body is placed in the StringInfo; the length word
    1192             :  *      is removed.  Also, s->cursor is initialized to zero for convenience
    1193             :  *      in scanning the message contents.
    1194             :  *
    1195             :  *      maxlen is the upper limit on the length of the
    1196             :  *      message we are willing to accept.  We abort the connection (by
    1197             :  *      returning EOF) if client tries to send more than that.
    1198             :  *
    1199             :  *      returns 0 if OK, EOF if trouble
    1200             :  * --------------------------------
    1201             :  */
    1202             : int
    1203     1300668 : pq_getmessage(StringInfo s, int maxlen)
    1204             : {
    1205             :     int32       len;
    1206             : 
    1207             :     Assert(PqCommReadingMsg);
    1208             : 
    1209     1300668 :     resetStringInfo(s);
    1210             : 
    1211             :     /* Read message length word */
    1212     1300668 :     if (pq_getbytes(&len, 4) == EOF)
    1213             :     {
    1214           0 :         ereport(COMMERROR,
    1215             :                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
    1216             :                  errmsg("unexpected EOF within message length word")));
    1217           0 :         return EOF;
    1218             :     }
    1219             : 
    1220     1300668 :     len = pg_ntoh32(len);
    1221             : 
    1222     1300668 :     if (len < 4 || len > maxlen)
    1223             :     {
    1224           0 :         ereport(COMMERROR,
    1225             :                 (errcode(ERRCODE_PROTOCOL_VIOLATION),
    1226             :                  errmsg("invalid message length")));
    1227           0 :         return EOF;
    1228             :     }
    1229             : 
    1230     1300668 :     len -= 4;                   /* discount length itself */
    1231             : 
    1232     1300668 :     if (len > 0)
    1233             :     {
    1234             :         /*
    1235             :          * Allocate space for message.  If we run out of room (ridiculously
    1236             :          * large message), we will elog(ERROR), but we want to discard the
    1237             :          * message body so as not to lose communication sync.
    1238             :          */
    1239     1250842 :         PG_TRY();
    1240             :         {
    1241     1250842 :             enlargeStringInfo(s, len);
    1242             :         }
    1243           0 :         PG_CATCH();
    1244             :         {
    1245           0 :             if (pq_discardbytes(len) == EOF)
    1246           0 :                 ereport(COMMERROR,
    1247             :                         (errcode(ERRCODE_PROTOCOL_VIOLATION),
    1248             :                          errmsg("incomplete message from client")));
    1249             : 
    1250             :             /* we discarded the rest of the message so we're back in sync. */
    1251           0 :             PqCommReadingMsg = false;
    1252           0 :             PG_RE_THROW();
    1253             :         }
    1254     1250842 :         PG_END_TRY();
    1255             : 
    1256             :         /* And grab the message */
    1257     1250842 :         if (pq_getbytes(s->data, len) == EOF)
    1258             :         {
    1259           0 :             ereport(COMMERROR,
    1260             :                     (errcode(ERRCODE_PROTOCOL_VIOLATION),
    1261             :                      errmsg("incomplete message from client")));
    1262           0 :             return EOF;
    1263             :         }
    1264     1250842 :         s->len = len;
    1265             :         /* Place a trailing null per StringInfo convention */
    1266     1250842 :         s->data[len] = '\0';
    1267             :     }
    1268             : 
    1269             :     /* finished reading the message. */
    1270     1300668 :     PqCommReadingMsg = false;
    1271             : 
    1272     1300668 :     return 0;
    1273             : }
    1274             : 
    1275             : 
    1276             : static inline int
    1277    41972418 : internal_putbytes(const void *b, size_t len)
    1278             : {
    1279    41972418 :     const char *s = b;
    1280             : 
    1281    84283788 :     while (len > 0)
    1282             :     {
    1283             :         /* If buffer is full, then flush it out */
    1284    42311378 :         if (PqSendPointer >= PqSendBufferSize)
    1285             :         {
    1286      399262 :             socket_set_nonblocking(false);
    1287      399262 :             if (internal_flush())
    1288           8 :                 return EOF;
    1289             :         }
    1290             : 
    1291             :         /*
    1292             :          * If the buffer is empty and data length is larger than the buffer
    1293             :          * size, send it without buffering.  Otherwise, copy as much data as
    1294             :          * possible into the buffer.
    1295             :          */
    1296    42311370 :         if (len >= PqSendBufferSize && PqSendStart == PqSendPointer)
    1297      222456 :         {
    1298      222456 :             size_t      start = 0;
    1299             : 
    1300      222456 :             socket_set_nonblocking(false);
    1301      222456 :             if (internal_flush_buffer(s, &start, &len))
    1302           0 :                 return EOF;
    1303             :         }
    1304             :         else
    1305             :         {
    1306    42088914 :             size_t      amount = PqSendBufferSize - PqSendPointer;
    1307             : 
    1308    42088914 :             if (amount > len)
    1309    41506958 :                 amount = len;
    1310    42088914 :             memcpy(PqSendBuffer + PqSendPointer, s, amount);
    1311    42088914 :             PqSendPointer += amount;
    1312    42088914 :             s += amount;
    1313    42088914 :             len -= amount;
    1314             :         }
    1315             :     }
    1316             : 
    1317    41972410 :     return 0;
    1318             : }
    1319             : 
    1320             : /* --------------------------------
    1321             :  *      socket_flush        - flush pending output
    1322             :  *
    1323             :  *      returns 0 if OK, EOF if trouble
    1324             :  * --------------------------------
    1325             :  */
    1326             : static int
    1327      838240 : socket_flush(void)
    1328             : {
    1329             :     int         res;
    1330             : 
    1331             :     /* No-op if reentrant call */
    1332      838240 :     if (PqCommBusy)
    1333           0 :         return 0;
    1334      838240 :     PqCommBusy = true;
    1335      838240 :     socket_set_nonblocking(false);
    1336      838240 :     res = internal_flush();
    1337      838240 :     PqCommBusy = false;
    1338      838240 :     return res;
    1339             : }
    1340             : 
    1341             : /* --------------------------------
    1342             :  *      internal_flush - flush pending output
    1343             :  *
    1344             :  * Returns 0 if OK (meaning everything was sent, or operation would block
    1345             :  * and the socket is in non-blocking mode), or EOF if trouble.
    1346             :  * --------------------------------
    1347             :  */
    1348             : static inline int
    1349     1883432 : internal_flush(void)
    1350             : {
    1351     1883432 :     return internal_flush_buffer(PqSendBuffer, &PqSendStart, &PqSendPointer);
    1352             : }
    1353             : 
    1354             : /* --------------------------------
    1355             :  *      internal_flush_buffer - flush the given buffer content
    1356             :  *
    1357             :  * Returns 0 if OK (meaning everything was sent, or operation would block
    1358             :  * and the socket is in non-blocking mode), or EOF if trouble.
    1359             :  * --------------------------------
    1360             :  */
    1361             : static pg_noinline int
    1362     2105888 : internal_flush_buffer(const char *buf, size_t *start, size_t *end)
    1363             : {
    1364             :     static int  last_reported_send_errno = 0;
    1365             : 
    1366     2105888 :     const char *bufptr = buf + *start;
    1367     2105888 :     const char *bufend = buf + *end;
    1368             : 
    1369     4172842 :     while (bufptr < bufend)
    1370             :     {
    1371             :         int         r;
    1372             : 
    1373     2137298 :         r = secure_write(MyProcPort, bufptr, bufend - bufptr);
    1374             : 
    1375     2137298 :         if (r <= 0)
    1376             :         {
    1377       70344 :             if (errno == EINTR)
    1378           0 :                 continue;       /* Ok if we were interrupted */
    1379             : 
    1380             :             /*
    1381             :              * Ok if no data writable without blocking, and the socket is in
    1382             :              * non-blocking mode.
    1383             :              */
    1384       70344 :             if (errno == EAGAIN ||
    1385          84 :                 errno == EWOULDBLOCK)
    1386             :             {
    1387       70260 :                 return 0;
    1388             :             }
    1389             : 
    1390             :             /*
    1391             :              * Careful: an ereport() that tries to write to the client would
    1392             :              * cause recursion to here, leading to stack overflow and core
    1393             :              * dump!  This message must go *only* to the postmaster log.
    1394             :              *
    1395             :              * If a client disconnects while we're in the midst of output, we
    1396             :              * might write quite a bit of data before we get to a safe query
    1397             :              * abort point.  So, suppress duplicate log messages.
    1398             :              */
    1399          84 :             if (errno != last_reported_send_errno)
    1400             :             {
    1401          82 :                 last_reported_send_errno = errno;
    1402          82 :                 ereport(COMMERROR,
    1403             :                         (errcode_for_socket_access(),
    1404             :                          errmsg("could not send data to client: %m")));
    1405             :             }
    1406             : 
    1407             :             /*
    1408             :              * We drop the buffered data anyway so that processing can
    1409             :              * continue, even though we'll probably quit soon. We also set a
    1410             :              * flag that'll cause the next CHECK_FOR_INTERRUPTS to terminate
    1411             :              * the connection.
    1412             :              */
    1413          84 :             *start = *end = 0;
    1414          84 :             ClientConnectionLost = 1;
    1415          84 :             InterruptPending = 1;
    1416          84 :             return EOF;
    1417             :         }
    1418             : 
    1419     2066954 :         last_reported_send_errno = 0;   /* reset after any successful send */
    1420     2066954 :         bufptr += r;
    1421     2066954 :         *start += r;
    1422             :     }
    1423             : 
    1424     2035544 :     *start = *end = 0;
    1425     2035544 :     return 0;
    1426             : }
    1427             : 
    1428             : /* --------------------------------
    1429             :  *      pq_flush_if_writable - flush pending output if writable without blocking
    1430             :  *
    1431             :  * Returns 0 if OK, or EOF if trouble.
    1432             :  * --------------------------------
    1433             :  */
    1434             : static int
    1435     3778762 : socket_flush_if_writable(void)
    1436             : {
    1437             :     int         res;
    1438             : 
    1439             :     /* Quick exit if nothing to do */
    1440     3778762 :     if (PqSendPointer == PqSendStart)
    1441     3132832 :         return 0;
    1442             : 
    1443             :     /* No-op if reentrant call */
    1444      645930 :     if (PqCommBusy)
    1445           0 :         return 0;
    1446             : 
    1447             :     /* Temporarily put the socket into non-blocking mode */
    1448      645930 :     socket_set_nonblocking(true);
    1449             : 
    1450      645930 :     PqCommBusy = true;
    1451      645930 :     res = internal_flush();
    1452      645930 :     PqCommBusy = false;
    1453      645930 :     return res;
    1454             : }
    1455             : 
    1456             : /* --------------------------------
    1457             :  *  socket_is_send_pending  - is there any pending data in the output buffer?
    1458             :  * --------------------------------
    1459             :  */
    1460             : static bool
    1461     8734098 : socket_is_send_pending(void)
    1462             : {
    1463     8734098 :     return (PqSendStart < PqSendPointer);
    1464             : }
    1465             : 
    1466             : /* --------------------------------
    1467             :  * Message-level I/O routines begin here.
    1468             :  * --------------------------------
    1469             :  */
    1470             : 
    1471             : 
    1472             : /* --------------------------------
    1473             :  *      socket_putmessage - send a normal message (suppressed in COPY OUT mode)
    1474             :  *
    1475             :  *      msgtype is a message type code to place before the message body.
    1476             :  *
    1477             :  *      len is the length of the message body data at *s.  A message length
    1478             :  *      word (equal to len+4 because it counts itself too) is inserted by this
    1479             :  *      routine.
    1480             :  *
    1481             :  *      We suppress messages generated while pqcomm.c is busy.  This
    1482             :  *      avoids any possibility of messages being inserted within other
    1483             :  *      messages.  The only known trouble case arises if SIGQUIT occurs
    1484             :  *      during a pqcomm.c routine --- quickdie() will try to send a warning
    1485             :  *      message, and the most reasonable approach seems to be to drop it.
    1486             :  *
    1487             :  *      returns 0 if OK, EOF if trouble
    1488             :  * --------------------------------
    1489             :  */
    1490             : static int
    1491    13990806 : socket_putmessage(char msgtype, const char *s, size_t len)
    1492             : {
    1493             :     uint32      n32;
    1494             : 
    1495             :     Assert(msgtype != 0);
    1496             : 
    1497    13990806 :     if (PqCommBusy)
    1498           0 :         return 0;
    1499    13990806 :     PqCommBusy = true;
    1500    13990806 :     if (internal_putbytes(&msgtype, 1))
    1501           0 :         goto fail;
    1502             : 
    1503    13990806 :     n32 = pg_hton32((uint32) (len + 4));
    1504    13990806 :     if (internal_putbytes(&n32, 4))
    1505           0 :         goto fail;
    1506             : 
    1507    13990806 :     if (internal_putbytes(s, len))
    1508           8 :         goto fail;
    1509    13990798 :     PqCommBusy = false;
    1510    13990798 :     return 0;
    1511             : 
    1512           8 : fail:
    1513           8 :     PqCommBusy = false;
    1514           8 :     return EOF;
    1515             : }
    1516             : 
    1517             : /* --------------------------------
    1518             :  *      pq_putmessage_noblock   - like pq_putmessage, but never blocks
    1519             :  *
    1520             :  *      If the output buffer is too small to hold the message, the buffer
    1521             :  *      is enlarged.
    1522             :  */
    1523             : static void
    1524      575412 : socket_putmessage_noblock(char msgtype, const char *s, size_t len)
    1525             : {
    1526             :     int         res PG_USED_FOR_ASSERTS_ONLY;
    1527             :     int         required;
    1528             : 
    1529             :     /*
    1530             :      * Ensure we have enough space in the output buffer for the message header
    1531             :      * as well as the message itself.
    1532             :      */
    1533      575412 :     required = PqSendPointer + 1 + 4 + len;
    1534      575412 :     if (required > PqSendBufferSize)
    1535             :     {
    1536         950 :         PqSendBuffer = repalloc(PqSendBuffer, required);
    1537         950 :         PqSendBufferSize = required;
    1538             :     }
    1539      575412 :     res = pq_putmessage(msgtype, s, len);
    1540             :     Assert(res == 0);           /* should not fail when the message fits in
    1541             :                                  * buffer */
    1542      575412 : }
    1543             : 
    1544             : /* --------------------------------
    1545             :  *      pq_putmessage_v2 - send a message in protocol version 2
    1546             :  *
    1547             :  *      msgtype is a message type code to place before the message body.
    1548             :  *
    1549             :  *      We no longer support protocol version 2, but we have kept this
    1550             :  *      function so that if a client tries to connect with protocol version 2,
    1551             :  *      as a courtesy we can still send the "unsupported protocol version"
    1552             :  *      error to the client in the old format.
    1553             :  *
    1554             :  *      Like in pq_putmessage(), we suppress messages generated while
    1555             :  *      pqcomm.c is busy.
    1556             :  *
    1557             :  *      returns 0 if OK, EOF if trouble
    1558             :  * --------------------------------
    1559             :  */
    1560             : int
    1561           0 : pq_putmessage_v2(char msgtype, const char *s, size_t len)
    1562             : {
    1563             :     Assert(msgtype != 0);
    1564             : 
    1565           0 :     if (PqCommBusy)
    1566           0 :         return 0;
    1567           0 :     PqCommBusy = true;
    1568           0 :     if (internal_putbytes(&msgtype, 1))
    1569           0 :         goto fail;
    1570             : 
    1571           0 :     if (internal_putbytes(s, len))
    1572           0 :         goto fail;
    1573           0 :     PqCommBusy = false;
    1574           0 :     return 0;
    1575             : 
    1576           0 : fail:
    1577           0 :     PqCommBusy = false;
    1578           0 :     return EOF;
    1579             : }
    1580             : 
    1581             : /*
    1582             :  * Support for TCP Keepalive parameters
    1583             :  */
    1584             : 
    1585             : /*
    1586             :  * On Windows, we need to set both idle and interval at the same time.
    1587             :  * We also cannot reset them to the default (setting to zero will
    1588             :  * actually set them to zero, not default), therefore we fallback to
    1589             :  * the out-of-the-box default instead.
    1590             :  */
    1591             : #if defined(WIN32) && defined(SIO_KEEPALIVE_VALS)
    1592             : static int
    1593             : pq_setkeepaliveswin32(Port *port, int idle, int interval)
    1594             : {
    1595             :     struct tcp_keepalive ka;
    1596             :     DWORD       retsize;
    1597             : 
    1598             :     if (idle <= 0)
    1599             :         idle = 2 * 60 * 60;     /* default = 2 hours */
    1600             :     if (interval <= 0)
    1601             :         interval = 1;           /* default = 1 second */
    1602             : 
    1603             :     ka.onoff = 1;
    1604             :     ka.keepalivetime = idle * 1000;
    1605             :     ka.keepaliveinterval = interval * 1000;
    1606             : 
    1607             :     if (WSAIoctl(port->sock,
    1608             :                  SIO_KEEPALIVE_VALS,
    1609             :                  (LPVOID) &ka,
    1610             :                  sizeof(ka),
    1611             :                  NULL,
    1612             :                  0,
    1613             :                  &retsize,
    1614             :                  NULL,
    1615             :                  NULL)
    1616             :         != 0)
    1617             :     {
    1618             :         ereport(LOG,
    1619             :                 (errmsg("%s(%s) failed: error code %d",
    1620             :                         "WSAIoctl", "SIO_KEEPALIVE_VALS", WSAGetLastError())));
    1621             :         return STATUS_ERROR;
    1622             :     }
    1623             :     if (port->keepalives_idle != idle)
    1624             :         port->keepalives_idle = idle;
    1625             :     if (port->keepalives_interval != interval)
    1626             :         port->keepalives_interval = interval;
    1627             :     return STATUS_OK;
    1628             : }
    1629             : #endif
    1630             : 
    1631             : int
    1632        3450 : pq_getkeepalivesidle(Port *port)
    1633             : {
    1634             : #if defined(PG_TCP_KEEPALIVE_IDLE) || defined(SIO_KEEPALIVE_VALS)
    1635        3450 :     if (port == NULL || port->laddr.addr.ss_family == AF_UNIX)
    1636        3450 :         return 0;
    1637             : 
    1638           0 :     if (port->keepalives_idle != 0)
    1639           0 :         return port->keepalives_idle;
    1640             : 
    1641           0 :     if (port->default_keepalives_idle == 0)
    1642             :     {
    1643             : #ifndef WIN32
    1644           0 :         socklen_t   size = sizeof(port->default_keepalives_idle);
    1645             : 
    1646           0 :         if (getsockopt(port->sock, IPPROTO_TCP, PG_TCP_KEEPALIVE_IDLE,
    1647           0 :                        (char *) &port->default_keepalives_idle,
    1648             :                        &size) < 0)
    1649             :         {
    1650           0 :             ereport(LOG,
    1651             :                     (errmsg("%s(%s) failed: %m", "getsockopt", PG_TCP_KEEPALIVE_IDLE_STR)));
    1652           0 :             port->default_keepalives_idle = -1; /* don't know */
    1653             :         }
    1654             : #else                           /* WIN32 */
    1655             :         /* We can't get the defaults on Windows, so return "don't know" */
    1656             :         port->default_keepalives_idle = -1;
    1657             : #endif                          /* WIN32 */
    1658             :     }
    1659             : 
    1660           0 :     return port->default_keepalives_idle;
    1661             : #else
    1662             :     return 0;
    1663             : #endif
    1664             : }
    1665             : 
    1666             : int
    1667        2782 : pq_setkeepalivesidle(int idle, Port *port)
    1668             : {
    1669        2782 :     if (port == NULL || port->laddr.addr.ss_family == AF_UNIX)
    1670        2204 :         return STATUS_OK;
    1671             : 
    1672             : /* check SIO_KEEPALIVE_VALS here, not just WIN32, as some toolchains lack it */
    1673             : #if defined(PG_TCP_KEEPALIVE_IDLE) || defined(SIO_KEEPALIVE_VALS)
    1674         578 :     if (idle == port->keepalives_idle)
    1675         578 :         return STATUS_OK;
    1676             : 
    1677             : #ifndef WIN32
    1678           0 :     if (port->default_keepalives_idle <= 0)
    1679             :     {
    1680           0 :         if (pq_getkeepalivesidle(port) < 0)
    1681             :         {
    1682           0 :             if (idle == 0)
    1683           0 :                 return STATUS_OK;   /* default is set but unknown */
    1684             :             else
    1685           0 :                 return STATUS_ERROR;
    1686             :         }
    1687             :     }
    1688             : 
    1689           0 :     if (idle == 0)
    1690           0 :         idle = port->default_keepalives_idle;
    1691             : 
    1692           0 :     if (setsockopt(port->sock, IPPROTO_TCP, PG_TCP_KEEPALIVE_IDLE,
    1693             :                    (char *) &idle, sizeof(idle)) < 0)
    1694             :     {
    1695           0 :         ereport(LOG,
    1696             :                 (errmsg("%s(%s) failed: %m", "setsockopt", PG_TCP_KEEPALIVE_IDLE_STR)));
    1697           0 :         return STATUS_ERROR;
    1698             :     }
    1699             : 
    1700           0 :     port->keepalives_idle = idle;
    1701             : #else                           /* WIN32 */
    1702             :     return pq_setkeepaliveswin32(port, idle, port->keepalives_interval);
    1703             : #endif
    1704             : #else
    1705             :     if (idle != 0)
    1706             :     {
    1707             :         ereport(LOG,
    1708             :                 (errmsg("setting the keepalive idle time is not supported")));
    1709             :         return STATUS_ERROR;
    1710             :     }
    1711             : #endif
    1712             : 
    1713           0 :     return STATUS_OK;
    1714             : }
    1715             : 
    1716             : int
    1717        3450 : pq_getkeepalivesinterval(Port *port)
    1718             : {
    1719             : #if defined(TCP_KEEPINTVL) || defined(SIO_KEEPALIVE_VALS)
    1720        3450 :     if (port == NULL || port->laddr.addr.ss_family == AF_UNIX)
    1721        3450 :         return 0;
    1722             : 
    1723           0 :     if (port->keepalives_interval != 0)
    1724           0 :         return port->keepalives_interval;
    1725             : 
    1726           0 :     if (port->default_keepalives_interval == 0)
    1727             :     {
    1728             : #ifndef WIN32
    1729           0 :         socklen_t   size = sizeof(port->default_keepalives_interval);
    1730             : 
    1731           0 :         if (getsockopt(port->sock, IPPROTO_TCP, TCP_KEEPINTVL,
    1732           0 :                        (char *) &port->default_keepalives_interval,
    1733             :                        &size) < 0)
    1734             :         {
    1735           0 :             ereport(LOG,
    1736             :                     (errmsg("%s(%s) failed: %m", "getsockopt", "TCP_KEEPINTVL")));
    1737           0 :             port->default_keepalives_interval = -1; /* don't know */
    1738             :         }
    1739             : #else
    1740             :         /* We can't get the defaults on Windows, so return "don't know" */
    1741             :         port->default_keepalives_interval = -1;
    1742             : #endif                          /* WIN32 */
    1743             :     }
    1744             : 
    1745           0 :     return port->default_keepalives_interval;
    1746             : #else
    1747             :     return 0;
    1748             : #endif
    1749             : }
    1750             : 
    1751             : int
    1752        2782 : pq_setkeepalivesinterval(int interval, Port *port)
    1753             : {
    1754        2782 :     if (port == NULL || port->laddr.addr.ss_family == AF_UNIX)
    1755        2204 :         return STATUS_OK;
    1756             : 
    1757             : #if defined(TCP_KEEPINTVL) || defined(SIO_KEEPALIVE_VALS)
    1758         578 :     if (interval == port->keepalives_interval)
    1759         578 :         return STATUS_OK;
    1760             : 
    1761             : #ifndef WIN32
    1762           0 :     if (port->default_keepalives_interval <= 0)
    1763             :     {
    1764           0 :         if (pq_getkeepalivesinterval(port) < 0)
    1765             :         {
    1766           0 :             if (interval == 0)
    1767           0 :                 return STATUS_OK;   /* default is set but unknown */
    1768             :             else
    1769           0 :                 return STATUS_ERROR;
    1770             :         }
    1771             :     }
    1772             : 
    1773           0 :     if (interval == 0)
    1774           0 :         interval = port->default_keepalives_interval;
    1775             : 
    1776           0 :     if (setsockopt(port->sock, IPPROTO_TCP, TCP_KEEPINTVL,
    1777             :                    (char *) &interval, sizeof(interval)) < 0)
    1778             :     {
    1779           0 :         ereport(LOG,
    1780             :                 (errmsg("%s(%s) failed: %m", "setsockopt", "TCP_KEEPINTVL")));
    1781           0 :         return STATUS_ERROR;
    1782             :     }
    1783             : 
    1784           0 :     port->keepalives_interval = interval;
    1785             : #else                           /* WIN32 */
    1786             :     return pq_setkeepaliveswin32(port, port->keepalives_idle, interval);
    1787             : #endif
    1788             : #else
    1789             :     if (interval != 0)
    1790             :     {
    1791             :         ereport(LOG,
    1792             :                 (errmsg("%s(%s) not supported", "setsockopt", "TCP_KEEPINTVL")));
    1793             :         return STATUS_ERROR;
    1794             :     }
    1795             : #endif
    1796             : 
    1797           0 :     return STATUS_OK;
    1798             : }
    1799             : 
    1800             : int
    1801        3450 : pq_getkeepalivescount(Port *port)
    1802             : {
    1803             : #ifdef TCP_KEEPCNT
    1804        3450 :     if (port == NULL || port->laddr.addr.ss_family == AF_UNIX)
    1805        3450 :         return 0;
    1806             : 
    1807           0 :     if (port->keepalives_count != 0)
    1808           0 :         return port->keepalives_count;
    1809             : 
    1810           0 :     if (port->default_keepalives_count == 0)
    1811             :     {
    1812           0 :         socklen_t   size = sizeof(port->default_keepalives_count);
    1813             : 
    1814           0 :         if (getsockopt(port->sock, IPPROTO_TCP, TCP_KEEPCNT,
    1815           0 :                        (char *) &port->default_keepalives_count,
    1816             :                        &size) < 0)
    1817             :         {
    1818           0 :             ereport(LOG,
    1819             :                     (errmsg("%s(%s) failed: %m", "getsockopt", "TCP_KEEPCNT")));
    1820           0 :             port->default_keepalives_count = -1; /* don't know */
    1821             :         }
    1822             :     }
    1823             : 
    1824           0 :     return port->default_keepalives_count;
    1825             : #else
    1826             :     return 0;
    1827             : #endif
    1828             : }
    1829             : 
    1830             : int
    1831        2782 : pq_setkeepalivescount(int count, Port *port)
    1832             : {
    1833        2782 :     if (port == NULL || port->laddr.addr.ss_family == AF_UNIX)
    1834        2204 :         return STATUS_OK;
    1835             : 
    1836             : #ifdef TCP_KEEPCNT
    1837         578 :     if (count == port->keepalives_count)
    1838         578 :         return STATUS_OK;
    1839             : 
    1840           0 :     if (port->default_keepalives_count <= 0)
    1841             :     {
    1842           0 :         if (pq_getkeepalivescount(port) < 0)
    1843             :         {
    1844           0 :             if (count == 0)
    1845           0 :                 return STATUS_OK;   /* default is set but unknown */
    1846             :             else
    1847           0 :                 return STATUS_ERROR;
    1848             :         }
    1849             :     }
    1850             : 
    1851           0 :     if (count == 0)
    1852           0 :         count = port->default_keepalives_count;
    1853             : 
    1854           0 :     if (setsockopt(port->sock, IPPROTO_TCP, TCP_KEEPCNT,
    1855             :                    (char *) &count, sizeof(count)) < 0)
    1856             :     {
    1857           0 :         ereport(LOG,
    1858             :                 (errmsg("%s(%s) failed: %m", "setsockopt", "TCP_KEEPCNT")));
    1859           0 :         return STATUS_ERROR;
    1860             :     }
    1861             : 
    1862           0 :     port->keepalives_count = count;
    1863             : #else
    1864             :     if (count != 0)
    1865             :     {
    1866             :         ereport(LOG,
    1867             :                 (errmsg("%s(%s) not supported", "setsockopt", "TCP_KEEPCNT")));
    1868             :         return STATUS_ERROR;
    1869             :     }
    1870             : #endif
    1871             : 
    1872           0 :     return STATUS_OK;
    1873             : }
    1874             : 
    1875             : int
    1876        3450 : pq_gettcpusertimeout(Port *port)
    1877             : {
    1878             : #ifdef TCP_USER_TIMEOUT
    1879        3450 :     if (port == NULL || port->laddr.addr.ss_family == AF_UNIX)
    1880        3450 :         return 0;
    1881             : 
    1882           0 :     if (port->tcp_user_timeout != 0)
    1883           0 :         return port->tcp_user_timeout;
    1884             : 
    1885           0 :     if (port->default_tcp_user_timeout == 0)
    1886             :     {
    1887           0 :         socklen_t   size = sizeof(port->default_tcp_user_timeout);
    1888             : 
    1889           0 :         if (getsockopt(port->sock, IPPROTO_TCP, TCP_USER_TIMEOUT,
    1890           0 :                        (char *) &port->default_tcp_user_timeout,
    1891             :                        &size) < 0)
    1892             :         {
    1893           0 :             ereport(LOG,
    1894             :                     (errmsg("%s(%s) failed: %m", "getsockopt", "TCP_USER_TIMEOUT")));
    1895           0 :             port->default_tcp_user_timeout = -1; /* don't know */
    1896             :         }
    1897             :     }
    1898             : 
    1899           0 :     return port->default_tcp_user_timeout;
    1900             : #else
    1901             :     return 0;
    1902             : #endif
    1903             : }
    1904             : 
    1905             : int
    1906        2782 : pq_settcpusertimeout(int timeout, Port *port)
    1907             : {
    1908        2782 :     if (port == NULL || port->laddr.addr.ss_family == AF_UNIX)
    1909        2204 :         return STATUS_OK;
    1910             : 
    1911             : #ifdef TCP_USER_TIMEOUT
    1912         578 :     if (timeout == port->tcp_user_timeout)
    1913         578 :         return STATUS_OK;
    1914             : 
    1915           0 :     if (port->default_tcp_user_timeout <= 0)
    1916             :     {
    1917           0 :         if (pq_gettcpusertimeout(port) < 0)
    1918             :         {
    1919           0 :             if (timeout == 0)
    1920           0 :                 return STATUS_OK;   /* default is set but unknown */
    1921             :             else
    1922           0 :                 return STATUS_ERROR;
    1923             :         }
    1924             :     }
    1925             : 
    1926           0 :     if (timeout == 0)
    1927           0 :         timeout = port->default_tcp_user_timeout;
    1928             : 
    1929           0 :     if (setsockopt(port->sock, IPPROTO_TCP, TCP_USER_TIMEOUT,
    1930             :                    (char *) &timeout, sizeof(timeout)) < 0)
    1931             :     {
    1932           0 :         ereport(LOG,
    1933             :                 (errmsg("%s(%s) failed: %m", "setsockopt", "TCP_USER_TIMEOUT")));
    1934           0 :         return STATUS_ERROR;
    1935             :     }
    1936             : 
    1937           0 :     port->tcp_user_timeout = timeout;
    1938             : #else
    1939             :     if (timeout != 0)
    1940             :     {
    1941             :         ereport(LOG,
    1942             :                 (errmsg("%s(%s) not supported", "setsockopt", "TCP_USER_TIMEOUT")));
    1943             :         return STATUS_ERROR;
    1944             :     }
    1945             : #endif
    1946             : 
    1947           0 :     return STATUS_OK;
    1948             : }
    1949             : 
    1950             : /*
    1951             :  * GUC assign_hook for tcp_keepalives_idle
    1952             :  */
    1953             : void
    1954        2204 : assign_tcp_keepalives_idle(int newval, void *extra)
    1955             : {
    1956             :     /*
    1957             :      * The kernel API provides no way to test a value without setting it; and
    1958             :      * once we set it we might fail to unset it.  So there seems little point
    1959             :      * in fully implementing the check-then-assign GUC API for these
    1960             :      * variables.  Instead we just do the assignment on demand.
    1961             :      * pq_setkeepalivesidle reports any problems via ereport(LOG).
    1962             :      *
    1963             :      * This approach means that the GUC value might have little to do with the
    1964             :      * actual kernel value, so we use a show_hook that retrieves the kernel
    1965             :      * value rather than trusting GUC's copy.
    1966             :      */
    1967        2204 :     (void) pq_setkeepalivesidle(newval, MyProcPort);
    1968        2204 : }
    1969             : 
    1970             : /*
    1971             :  * GUC show_hook for tcp_keepalives_idle
    1972             :  */
    1973             : const char *
    1974        3450 : show_tcp_keepalives_idle(void)
    1975             : {
    1976             :     /* See comments in assign_tcp_keepalives_idle */
    1977             :     static char nbuf[16];
    1978             : 
    1979        3450 :     snprintf(nbuf, sizeof(nbuf), "%d", pq_getkeepalivesidle(MyProcPort));
    1980        3450 :     return nbuf;
    1981             : }
    1982             : 
    1983             : /*
    1984             :  * GUC assign_hook for tcp_keepalives_interval
    1985             :  */
    1986             : void
    1987        2204 : assign_tcp_keepalives_interval(int newval, void *extra)
    1988             : {
    1989             :     /* See comments in assign_tcp_keepalives_idle */
    1990        2204 :     (void) pq_setkeepalivesinterval(newval, MyProcPort);
    1991        2204 : }
    1992             : 
    1993             : /*
    1994             :  * GUC show_hook for tcp_keepalives_interval
    1995             :  */
    1996             : const char *
    1997        3450 : show_tcp_keepalives_interval(void)
    1998             : {
    1999             :     /* See comments in assign_tcp_keepalives_idle */
    2000             :     static char nbuf[16];
    2001             : 
    2002        3450 :     snprintf(nbuf, sizeof(nbuf), "%d", pq_getkeepalivesinterval(MyProcPort));
    2003        3450 :     return nbuf;
    2004             : }
    2005             : 
    2006             : /*
    2007             :  * GUC assign_hook for tcp_keepalives_count
    2008             :  */
    2009             : void
    2010        2204 : assign_tcp_keepalives_count(int newval, void *extra)
    2011             : {
    2012             :     /* See comments in assign_tcp_keepalives_idle */
    2013        2204 :     (void) pq_setkeepalivescount(newval, MyProcPort);
    2014        2204 : }
    2015             : 
    2016             : /*
    2017             :  * GUC show_hook for tcp_keepalives_count
    2018             :  */
    2019             : const char *
    2020        3450 : show_tcp_keepalives_count(void)
    2021             : {
    2022             :     /* See comments in assign_tcp_keepalives_idle */
    2023             :     static char nbuf[16];
    2024             : 
    2025        3450 :     snprintf(nbuf, sizeof(nbuf), "%d", pq_getkeepalivescount(MyProcPort));
    2026        3450 :     return nbuf;
    2027             : }
    2028             : 
    2029             : /*
    2030             :  * GUC assign_hook for tcp_user_timeout
    2031             :  */
    2032             : void
    2033        2204 : assign_tcp_user_timeout(int newval, void *extra)
    2034             : {
    2035             :     /* See comments in assign_tcp_keepalives_idle */
    2036        2204 :     (void) pq_settcpusertimeout(newval, MyProcPort);
    2037        2204 : }
    2038             : 
    2039             : /*
    2040             :  * GUC show_hook for tcp_user_timeout
    2041             :  */
    2042             : const char *
    2043        3450 : show_tcp_user_timeout(void)
    2044             : {
    2045             :     /* See comments in assign_tcp_keepalives_idle */
    2046             :     static char nbuf[16];
    2047             : 
    2048        3450 :     snprintf(nbuf, sizeof(nbuf), "%d", pq_gettcpusertimeout(MyProcPort));
    2049        3450 :     return nbuf;
    2050             : }
    2051             : 
    2052             : /*
    2053             :  * Check if the client is still connected.
    2054             :  */
    2055             : bool
    2056           0 : pq_check_connection(void)
    2057             : {
    2058             :     WaitEvent   events[FeBeWaitSetNEvents];
    2059             :     int         rc;
    2060             : 
    2061             :     /*
    2062             :      * It's OK to modify the socket event filter without restoring, because
    2063             :      * all FeBeWaitSet socket wait sites do the same.
    2064             :      */
    2065           0 :     ModifyWaitEvent(FeBeWaitSet, FeBeWaitSetSocketPos, WL_SOCKET_CLOSED, NULL);
    2066             : 
    2067           0 : retry:
    2068           0 :     rc = WaitEventSetWait(FeBeWaitSet, 0, events, lengthof(events), 0);
    2069           0 :     for (int i = 0; i < rc; ++i)
    2070             :     {
    2071           0 :         if (events[i].events & WL_SOCKET_CLOSED)
    2072           0 :             return false;
    2073           0 :         if (events[i].events & WL_LATCH_SET)
    2074             :         {
    2075             :             /*
    2076             :              * A latch event might be preventing other events from being
    2077             :              * reported.  Reset it and poll again.  No need to restore it
    2078             :              * because no code should expect latches to survive across
    2079             :              * CHECK_FOR_INTERRUPTS().
    2080             :              */
    2081           0 :             ResetLatch(MyLatch);
    2082           0 :             goto retry;
    2083             :         }
    2084             :     }
    2085             : 
    2086           0 :     return true;
    2087             : }

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