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Diffstat (limited to '')
| -rw-r--r-- | src/backend/libpq/pqcomm.c | 1976 |
1 files changed, 1976 insertions, 0 deletions
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c new file mode 100644 index 0000000..75392a8 --- /dev/null +++ b/src/backend/libpq/pqcomm.c @@ -0,0 +1,1976 @@ +/*------------------------------------------------------------------------- + * + * pqcomm.c + * Communication functions between the Frontend and the Backend + * + * These routines handle the low-level details of communication between + * frontend and backend. They just shove data across the communication + * channel, and are ignorant of the semantics of the data. + * + * To emit an outgoing message, use the routines in pqformat.c to construct + * the message in a buffer and then emit it in one call to pq_putmessage. + * There are no functions to send raw bytes or partial messages; this + * ensures that the channel will not be clogged by an incomplete message if + * execution is aborted by ereport(ERROR) partway through the message. + * + * At one time, libpq was shared between frontend and backend, but now + * the backend's "backend/libpq" is quite separate from "interfaces/libpq". + * All that remains is similarities of names to trap the unwary... + * + * Portions Copyright (c) 1996-2022, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/backend/libpq/pqcomm.c + * + *------------------------------------------------------------------------- + */ + +/*------------------------ + * INTERFACE ROUTINES + * + * setup/teardown: + * StreamServerPort - Open postmaster's server port + * StreamConnection - Create new connection with client + * StreamClose - Close a client/backend connection + * TouchSocketFiles - Protect socket files against /tmp cleaners + * pq_init - initialize libpq at backend startup + * socket_comm_reset - reset libpq during error recovery + * socket_close - shutdown libpq at backend exit + * + * low-level I/O: + * pq_getbytes - get a known number of bytes from connection + * pq_getmessage - get a message with length word from connection + * pq_getbyte - get next byte from connection + * pq_peekbyte - peek at next byte from connection + * pq_flush - flush pending output + * pq_flush_if_writable - flush pending output if writable without blocking + * pq_getbyte_if_available - get a byte if available without blocking + * + * message-level I/O + * pq_putmessage - send a normal message (suppressed in COPY OUT mode) + * pq_putmessage_noblock - buffer a normal message (suppressed in COPY OUT) + * + *------------------------ + */ +#include "postgres.h" + +#ifdef HAVE_POLL_H +#include <poll.h> +#endif +#include <signal.h> +#include <fcntl.h> +#include <grp.h> +#include <unistd.h> +#include <sys/file.h> +#include <sys/socket.h> +#include <sys/stat.h> +#include <sys/time.h> +#include <netdb.h> +#include <netinet/in.h> +#ifdef HAVE_NETINET_TCP_H +#include <netinet/tcp.h> +#endif +#include <utime.h> +#ifdef _MSC_VER /* mstcpip.h is missing on mingw */ +#include <mstcpip.h> +#endif + +#include "common/ip.h" +#include "libpq/libpq.h" +#include "miscadmin.h" +#include "port/pg_bswap.h" +#include "storage/ipc.h" +#include "utils/guc.h" +#include "utils/memutils.h" + +/* + * Cope with the various platform-specific ways to spell TCP keepalive socket + * options. This doesn't cover Windows, which as usual does its own thing. + */ +#if defined(TCP_KEEPIDLE) +/* TCP_KEEPIDLE is the name of this option on Linux and *BSD */ +#define PG_TCP_KEEPALIVE_IDLE TCP_KEEPIDLE +#define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPIDLE" +#elif defined(TCP_KEEPALIVE_THRESHOLD) +/* TCP_KEEPALIVE_THRESHOLD is the name of this option on Solaris >= 11 */ +#define PG_TCP_KEEPALIVE_IDLE TCP_KEEPALIVE_THRESHOLD +#define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPALIVE_THRESHOLD" +#elif defined(TCP_KEEPALIVE) && defined(__darwin__) +/* TCP_KEEPALIVE is the name of this option on macOS */ +/* Caution: Solaris has this symbol but it means something different */ +#define PG_TCP_KEEPALIVE_IDLE TCP_KEEPALIVE +#define PG_TCP_KEEPALIVE_IDLE_STR "TCP_KEEPALIVE" +#endif + +/* + * Configuration options + */ +int Unix_socket_permissions; +char *Unix_socket_group; + +/* Where the Unix socket files are (list of palloc'd strings) */ +static List *sock_paths = NIL; + +/* + * Buffers for low-level I/O. + * + * The receive buffer is fixed size. Send buffer is usually 8k, but can be + * enlarged by pq_putmessage_noblock() if the message doesn't fit otherwise. + */ + +#define PQ_SEND_BUFFER_SIZE 8192 +#define PQ_RECV_BUFFER_SIZE 8192 + +static char *PqSendBuffer; +static int PqSendBufferSize; /* Size send buffer */ +static int PqSendPointer; /* Next index to store a byte in PqSendBuffer */ +static int PqSendStart; /* Next index to send a byte in PqSendBuffer */ + +static char PqRecvBuffer[PQ_RECV_BUFFER_SIZE]; +static int PqRecvPointer; /* Next index to read a byte from PqRecvBuffer */ +static int PqRecvLength; /* End of data available in PqRecvBuffer */ + +/* + * Message status + */ +static bool PqCommBusy; /* busy sending data to the client */ +static bool PqCommReadingMsg; /* in the middle of reading a message */ + + +/* Internal functions */ +static void socket_comm_reset(void); +static void socket_close(int code, Datum arg); +static void socket_set_nonblocking(bool nonblocking); +static int socket_flush(void); +static int socket_flush_if_writable(void); +static bool socket_is_send_pending(void); +static int socket_putmessage(char msgtype, const char *s, size_t len); +static void socket_putmessage_noblock(char msgtype, const char *s, size_t len); +static int internal_putbytes(const char *s, size_t len); +static int internal_flush(void); + +#ifdef HAVE_UNIX_SOCKETS +static int Lock_AF_UNIX(const char *unixSocketDir, const char *unixSocketPath); +static int Setup_AF_UNIX(const char *sock_path); +#endif /* HAVE_UNIX_SOCKETS */ + +static const PQcommMethods PqCommSocketMethods = { + socket_comm_reset, + socket_flush, + socket_flush_if_writable, + socket_is_send_pending, + socket_putmessage, + socket_putmessage_noblock +}; + +const PQcommMethods *PqCommMethods = &PqCommSocketMethods; + +WaitEventSet *FeBeWaitSet; + + +/* -------------------------------- + * pq_init - initialize libpq at backend startup + * -------------------------------- + */ +void +pq_init(void) +{ + int socket_pos PG_USED_FOR_ASSERTS_ONLY; + int latch_pos PG_USED_FOR_ASSERTS_ONLY; + + /* initialize state variables */ + PqSendBufferSize = PQ_SEND_BUFFER_SIZE; + PqSendBuffer = MemoryContextAlloc(TopMemoryContext, PqSendBufferSize); + PqSendPointer = PqSendStart = PqRecvPointer = PqRecvLength = 0; + PqCommBusy = false; + PqCommReadingMsg = false; + + /* set up process-exit hook to close the socket */ + on_proc_exit(socket_close, 0); + + /* + * In backends (as soon as forked) we operate the underlying socket in + * nonblocking mode and use latches to implement blocking semantics if + * needed. That allows us to provide safely interruptible reads and + * writes. + * + * Use COMMERROR on failure, because ERROR would try to send the error to + * the client, which might require changing the mode again, leading to + * infinite recursion. + */ +#ifndef WIN32 + if (!pg_set_noblock(MyProcPort->sock)) + ereport(COMMERROR, + (errmsg("could not set socket to nonblocking mode: %m"))); +#endif + + FeBeWaitSet = CreateWaitEventSet(TopMemoryContext, FeBeWaitSetNEvents); + socket_pos = AddWaitEventToSet(FeBeWaitSet, WL_SOCKET_WRITEABLE, + MyProcPort->sock, NULL, NULL); + latch_pos = AddWaitEventToSet(FeBeWaitSet, WL_LATCH_SET, PGINVALID_SOCKET, + MyLatch, NULL); + AddWaitEventToSet(FeBeWaitSet, WL_POSTMASTER_DEATH, PGINVALID_SOCKET, + NULL, NULL); + + /* + * The event positions match the order we added them, but let's sanity + * check them to be sure. + */ + Assert(socket_pos == FeBeWaitSetSocketPos); + Assert(latch_pos == FeBeWaitSetLatchPos); +} + +/* -------------------------------- + * socket_comm_reset - reset libpq during error recovery + * + * This is called from error recovery at the outer idle loop. It's + * just to get us out of trouble if we somehow manage to elog() from + * inside a pqcomm.c routine (which ideally will never happen, but...) + * -------------------------------- + */ +static void +socket_comm_reset(void) +{ + /* Do not throw away pending data, but do reset the busy flag */ + PqCommBusy = false; +} + +/* -------------------------------- + * socket_close - shutdown libpq at backend exit + * + * This is the one pg_on_exit_callback in place during BackendInitialize(). + * That function's unusual signal handling constrains that this callback be + * safe to run at any instant. + * -------------------------------- + */ +static void +socket_close(int code, Datum arg) +{ + /* Nothing to do in a standalone backend, where MyProcPort is NULL. */ + if (MyProcPort != NULL) + { +#ifdef ENABLE_GSS + /* + * Shutdown GSSAPI layer. This section does nothing when interrupting + * BackendInitialize(), because pg_GSS_recvauth() makes first use of + * "ctx" and "cred". + * + * Note that we don't bother to free MyProcPort->gss, since we're + * about to exit anyway. + */ + if (MyProcPort->gss) + { + OM_uint32 min_s; + + if (MyProcPort->gss->ctx != GSS_C_NO_CONTEXT) + gss_delete_sec_context(&min_s, &MyProcPort->gss->ctx, NULL); + + if (MyProcPort->gss->cred != GSS_C_NO_CREDENTIAL) + gss_release_cred(&min_s, &MyProcPort->gss->cred); + } +#endif /* ENABLE_GSS */ + + /* + * Cleanly shut down SSL layer. Nowhere else does a postmaster child + * call this, so this is safe when interrupting BackendInitialize(). + */ + secure_close(MyProcPort); + + /* + * Formerly we did an explicit close() here, but it seems better to + * leave the socket open until the process dies. This allows clients + * to perform a "synchronous close" if they care --- wait till the + * transport layer reports connection closure, and you can be sure the + * backend has exited. + * + * We do set sock to PGINVALID_SOCKET to prevent any further I/O, + * though. + */ + MyProcPort->sock = PGINVALID_SOCKET; + } +} + + + +/* + * Streams -- wrapper around Unix socket system calls + * + * + * Stream functions are used for vanilla TCP connection protocol. + */ + + +/* + * StreamServerPort -- open a "listening" port to accept connections. + * + * family should be AF_UNIX or AF_UNSPEC; portNumber is the port number. + * For AF_UNIX ports, hostName should be NULL and unixSocketDir must be + * specified. For TCP ports, hostName is either NULL for all interfaces or + * the interface to listen on, and unixSocketDir is ignored (can be NULL). + * + * Successfully opened sockets are added to the ListenSocket[] array (of + * length MaxListen), at the first position that isn't PGINVALID_SOCKET. + * + * RETURNS: STATUS_OK or STATUS_ERROR + */ + +int +StreamServerPort(int family, const char *hostName, unsigned short portNumber, + const char *unixSocketDir, + pgsocket ListenSocket[], int MaxListen) +{ + pgsocket fd; + int err; + int maxconn; + int ret; + char portNumberStr[32]; + const char *familyDesc; + char familyDescBuf[64]; + const char *addrDesc; + char addrBuf[NI_MAXHOST]; + char *service; + struct addrinfo *addrs = NULL, + *addr; + struct addrinfo hint; + int listen_index = 0; + int added = 0; + +#ifdef HAVE_UNIX_SOCKETS + char unixSocketPath[MAXPGPATH]; +#endif +#if !defined(WIN32) || defined(IPV6_V6ONLY) + int one = 1; +#endif + + /* Initialize hint structure */ + MemSet(&hint, 0, sizeof(hint)); + hint.ai_family = family; + hint.ai_flags = AI_PASSIVE; + hint.ai_socktype = SOCK_STREAM; + +#ifdef HAVE_UNIX_SOCKETS + if (family == AF_UNIX) + { + /* + * Create unixSocketPath from portNumber and unixSocketDir and lock + * that file path + */ + UNIXSOCK_PATH(unixSocketPath, portNumber, unixSocketDir); + if (strlen(unixSocketPath) >= UNIXSOCK_PATH_BUFLEN) + { + ereport(LOG, + (errmsg("Unix-domain socket path \"%s\" is too long (maximum %d bytes)", + unixSocketPath, + (int) (UNIXSOCK_PATH_BUFLEN - 1)))); + return STATUS_ERROR; + } + if (Lock_AF_UNIX(unixSocketDir, unixSocketPath) != STATUS_OK) + return STATUS_ERROR; + service = unixSocketPath; + } + else +#endif /* HAVE_UNIX_SOCKETS */ + { + snprintf(portNumberStr, sizeof(portNumberStr), "%d", portNumber); + service = portNumberStr; + } + + ret = pg_getaddrinfo_all(hostName, service, &hint, &addrs); + if (ret || !addrs) + { + if (hostName) + ereport(LOG, + (errmsg("could not translate host name \"%s\", service \"%s\" to address: %s", + hostName, service, gai_strerror(ret)))); + else + ereport(LOG, + (errmsg("could not translate service \"%s\" to address: %s", + service, gai_strerror(ret)))); + if (addrs) + pg_freeaddrinfo_all(hint.ai_family, addrs); + return STATUS_ERROR; + } + + for (addr = addrs; addr; addr = addr->ai_next) + { + if (family != AF_UNIX && addr->ai_family == AF_UNIX) + { + /* + * Only set up a unix domain socket when they really asked for it. + * The service/port is different in that case. + */ + continue; + } + + /* See if there is still room to add 1 more socket. */ + for (; listen_index < MaxListen; listen_index++) + { + if (ListenSocket[listen_index] == PGINVALID_SOCKET) + break; + } + if (listen_index >= MaxListen) + { + ereport(LOG, + (errmsg("could not bind to all requested addresses: MAXLISTEN (%d) exceeded", + MaxListen))); + break; + } + + /* set up address family name for log messages */ + switch (addr->ai_family) + { + case AF_INET: + familyDesc = _("IPv4"); + break; +#ifdef HAVE_IPV6 + case AF_INET6: + familyDesc = _("IPv6"); + break; +#endif +#ifdef HAVE_UNIX_SOCKETS + case AF_UNIX: + familyDesc = _("Unix"); + break; +#endif + default: + snprintf(familyDescBuf, sizeof(familyDescBuf), + _("unrecognized address family %d"), + addr->ai_family); + familyDesc = familyDescBuf; + break; + } + + /* set up text form of address for log messages */ +#ifdef HAVE_UNIX_SOCKETS + if (addr->ai_family == AF_UNIX) + addrDesc = unixSocketPath; + else +#endif + { + pg_getnameinfo_all((const struct sockaddr_storage *) addr->ai_addr, + addr->ai_addrlen, + addrBuf, sizeof(addrBuf), + NULL, 0, + NI_NUMERICHOST); + addrDesc = addrBuf; + } + + if ((fd = socket(addr->ai_family, SOCK_STREAM, 0)) == PGINVALID_SOCKET) + { + ereport(LOG, + (errcode_for_socket_access(), + /* translator: first %s is IPv4, IPv6, or Unix */ + errmsg("could not create %s socket for address \"%s\": %m", + familyDesc, addrDesc))); + continue; + } + +#ifndef WIN32 + + /* + * Without the SO_REUSEADDR flag, a new postmaster can't be started + * right away after a stop or crash, giving "address already in use" + * error on TCP ports. + * + * On win32, however, this behavior only happens if the + * SO_EXCLUSIVEADDRUSE is set. With SO_REUSEADDR, win32 allows + * multiple servers to listen on the same address, resulting in + * unpredictable behavior. With no flags at all, win32 behaves as Unix + * with SO_REUSEADDR. + */ + if (addr->ai_family != AF_UNIX) + { + if ((setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, + (char *) &one, sizeof(one))) == -1) + { + ereport(LOG, + (errcode_for_socket_access(), + /* translator: third %s is IPv4, IPv6, or Unix */ + errmsg("%s(%s) failed for %s address \"%s\": %m", + "setsockopt", "SO_REUSEADDR", + familyDesc, addrDesc))); + closesocket(fd); + continue; + } + } +#endif + +#ifdef IPV6_V6ONLY + if (addr->ai_family == AF_INET6) + { + if (setsockopt(fd, IPPROTO_IPV6, IPV6_V6ONLY, + (char *) &one, sizeof(one)) == -1) + { + ereport(LOG, + (errcode_for_socket_access(), + /* translator: third %s is IPv4, IPv6, or Unix */ + errmsg("%s(%s) failed for %s address \"%s\": %m", + "setsockopt", "IPV6_V6ONLY", + familyDesc, addrDesc))); + closesocket(fd); + continue; + } + } +#endif + + /* + * Note: This might fail on some OS's, like Linux older than + * 2.4.21-pre3, that don't have the IPV6_V6ONLY socket option, and map + * ipv4 addresses to ipv6. It will show ::ffff:ipv4 for all ipv4 + * connections. + */ + err = bind(fd, addr->ai_addr, addr->ai_addrlen); + if (err < 0) + { + int saved_errno = errno; + + ereport(LOG, + (errcode_for_socket_access(), + /* translator: first %s is IPv4, IPv6, or Unix */ + errmsg("could not bind %s address \"%s\": %m", + familyDesc, addrDesc), + saved_errno == EADDRINUSE ? + (addr->ai_family == AF_UNIX ? + errhint("Is another postmaster already running on port %d?", + (int) portNumber) : + errhint("Is another postmaster already running on port %d?" + " If not, wait a few seconds and retry.", + (int) portNumber)) : 0)); + closesocket(fd); + continue; + } + +#ifdef HAVE_UNIX_SOCKETS + if (addr->ai_family == AF_UNIX) + { + if (Setup_AF_UNIX(service) != STATUS_OK) + { + closesocket(fd); + break; + } + } +#endif + + /* + * Select appropriate accept-queue length limit. PG_SOMAXCONN is only + * intended to provide a clamp on the request on platforms where an + * overly large request provokes a kernel error (are there any?). + */ + maxconn = MaxBackends * 2; + if (maxconn > PG_SOMAXCONN) + maxconn = PG_SOMAXCONN; + + err = listen(fd, maxconn); + if (err < 0) + { + ereport(LOG, + (errcode_for_socket_access(), + /* translator: first %s is IPv4, IPv6, or Unix */ + errmsg("could not listen on %s address \"%s\": %m", + familyDesc, addrDesc))); + closesocket(fd); + continue; + } + +#ifdef HAVE_UNIX_SOCKETS + if (addr->ai_family == AF_UNIX) + ereport(LOG, + (errmsg("listening on Unix socket \"%s\"", + addrDesc))); + else +#endif + ereport(LOG, + /* translator: first %s is IPv4 or IPv6 */ + (errmsg("listening on %s address \"%s\", port %d", + familyDesc, addrDesc, (int) portNumber))); + + ListenSocket[listen_index] = fd; + added++; + } + + pg_freeaddrinfo_all(hint.ai_family, addrs); + + if (!added) + return STATUS_ERROR; + + return STATUS_OK; +} + + +#ifdef HAVE_UNIX_SOCKETS + +/* + * Lock_AF_UNIX -- configure unix socket file path + */ +static int +Lock_AF_UNIX(const char *unixSocketDir, const char *unixSocketPath) +{ + /* no lock file for abstract sockets */ + if (unixSocketPath[0] == '@') + return STATUS_OK; + + /* + * Grab an interlock file associated with the socket file. + * + * Note: there are two reasons for using a socket lock file, rather than + * trying to interlock directly on the socket itself. First, it's a lot + * more portable, and second, it lets us remove any pre-existing socket + * file without race conditions. + */ + CreateSocketLockFile(unixSocketPath, true, unixSocketDir); + + /* + * Once we have the interlock, we can safely delete any pre-existing + * socket file to avoid failure at bind() time. + */ + (void) unlink(unixSocketPath); + + /* + * Remember socket file pathnames for later maintenance. + */ + sock_paths = lappend(sock_paths, pstrdup(unixSocketPath)); + + return STATUS_OK; +} + + +/* + * Setup_AF_UNIX -- configure unix socket permissions + */ +static int +Setup_AF_UNIX(const char *sock_path) +{ + /* no file system permissions for abstract sockets */ + if (sock_path[0] == '@') + return STATUS_OK; + + /* + * Fix socket ownership/permission if requested. Note we must do this + * before we listen() to avoid a window where unwanted connections could + * get accepted. + */ + Assert(Unix_socket_group); + if (Unix_socket_group[0] != '\0') + { +#ifdef WIN32 + elog(WARNING, "configuration item unix_socket_group is not supported on this platform"); +#else + char *endptr; + unsigned long val; + gid_t gid; + + val = strtoul(Unix_socket_group, &endptr, 10); + if (*endptr == '\0') + { /* numeric group id */ + gid = val; + } + else + { /* convert group name to id */ + struct group *gr; + + gr = getgrnam(Unix_socket_group); + if (!gr) + { + ereport(LOG, + (errmsg("group \"%s\" does not exist", + Unix_socket_group))); + return STATUS_ERROR; + } + gid = gr->gr_gid; + } + if (chown(sock_path, -1, gid) == -1) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not set group of file \"%s\": %m", + sock_path))); + return STATUS_ERROR; + } +#endif + } + + if (chmod(sock_path, Unix_socket_permissions) == -1) + { + ereport(LOG, + (errcode_for_file_access(), + errmsg("could not set permissions of file \"%s\": %m", + sock_path))); + return STATUS_ERROR; + } + return STATUS_OK; +} +#endif /* HAVE_UNIX_SOCKETS */ + + +/* + * StreamConnection -- create a new connection with client using + * server port. Set port->sock to the FD of the new connection. + * + * ASSUME: that this doesn't need to be non-blocking because + * the Postmaster uses select() to tell when the socket is ready for + * accept(). + * + * RETURNS: STATUS_OK or STATUS_ERROR + */ +int +StreamConnection(pgsocket server_fd, Port *port) +{ + /* accept connection and fill in the client (remote) address */ + port->raddr.salen = sizeof(port->raddr.addr); + if ((port->sock = accept(server_fd, + (struct sockaddr *) &port->raddr.addr, + &port->raddr.salen)) == PGINVALID_SOCKET) + { + ereport(LOG, + (errcode_for_socket_access(), + errmsg("could not accept new connection: %m"))); + + /* + * If accept() fails then postmaster.c will still see the server + * socket as read-ready, and will immediately try again. To avoid + * uselessly sucking lots of CPU, delay a bit before trying again. + * (The most likely reason for failure is being out of kernel file + * table slots; we can do little except hope some will get freed up.) + */ + pg_usleep(100000L); /* wait 0.1 sec */ + return STATUS_ERROR; + } + + /* fill in the server (local) address */ + port->laddr.salen = sizeof(port->laddr.addr); + if (getsockname(port->sock, + (struct sockaddr *) &port->laddr.addr, + &port->laddr.salen) < 0) + { + ereport(LOG, + (errmsg("%s() failed: %m", "getsockname"))); + return STATUS_ERROR; + } + + /* select NODELAY and KEEPALIVE options if it's a TCP connection */ + if (port->laddr.addr.ss_family != AF_UNIX) + { + int on; +#ifdef WIN32 + int oldopt; + int optlen; + int newopt; +#endif + +#ifdef TCP_NODELAY + on = 1; + if (setsockopt(port->sock, IPPROTO_TCP, TCP_NODELAY, + (char *) &on, sizeof(on)) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "setsockopt", "TCP_NODELAY"))); + return STATUS_ERROR; + } +#endif + on = 1; + if (setsockopt(port->sock, SOL_SOCKET, SO_KEEPALIVE, + (char *) &on, sizeof(on)) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "setsockopt", "SO_KEEPALIVE"))); + return STATUS_ERROR; + } + +#ifdef WIN32 + + /* + * This is a Win32 socket optimization. The OS send buffer should be + * large enough to send the whole Postgres send buffer in one go, or + * performance suffers. The Postgres send buffer can be enlarged if a + * very large message needs to be sent, but we won't attempt to + * enlarge the OS buffer if that happens, so somewhat arbitrarily + * ensure that the OS buffer is at least PQ_SEND_BUFFER_SIZE * 4. + * (That's 32kB with the current default). + * + * The default OS buffer size used to be 8kB in earlier Windows + * versions, but was raised to 64kB in Windows 2012. So it shouldn't + * be necessary to change it in later versions anymore. Changing it + * unnecessarily can even reduce performance, because setting + * SO_SNDBUF in the application disables the "dynamic send buffering" + * feature that was introduced in Windows 7. So before fiddling with + * SO_SNDBUF, check if the current buffer size is already large enough + * and only increase it if necessary. + * + * See https://support.microsoft.com/kb/823764/EN-US/ and + * https://msdn.microsoft.com/en-us/library/bb736549%28v=vs.85%29.aspx + */ + optlen = sizeof(oldopt); + if (getsockopt(port->sock, SOL_SOCKET, SO_SNDBUF, (char *) &oldopt, + &optlen) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "getsockopt", "SO_SNDBUF"))); + return STATUS_ERROR; + } + newopt = PQ_SEND_BUFFER_SIZE * 4; + if (oldopt < newopt) + { + if (setsockopt(port->sock, SOL_SOCKET, SO_SNDBUF, (char *) &newopt, + sizeof(newopt)) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "setsockopt", "SO_SNDBUF"))); + return STATUS_ERROR; + } + } +#endif + + /* + * Also apply the current keepalive parameters. If we fail to set a + * parameter, don't error out, because these aren't universally + * supported. (Note: you might think we need to reset the GUC + * variables to 0 in such a case, but it's not necessary because the + * show hooks for these variables report the truth anyway.) + */ + (void) pq_setkeepalivesidle(tcp_keepalives_idle, port); + (void) pq_setkeepalivesinterval(tcp_keepalives_interval, port); + (void) pq_setkeepalivescount(tcp_keepalives_count, port); + (void) pq_settcpusertimeout(tcp_user_timeout, port); + } + + return STATUS_OK; +} + +/* + * StreamClose -- close a client/backend connection + * + * NOTE: this is NOT used to terminate a session; it is just used to release + * the file descriptor in a process that should no longer have the socket + * open. (For example, the postmaster calls this after passing ownership + * of the connection to a child process.) It is expected that someone else + * still has the socket open. So, we only want to close the descriptor, + * we do NOT want to send anything to the far end. + */ +void +StreamClose(pgsocket sock) +{ + closesocket(sock); +} + +/* + * TouchSocketFiles -- mark socket files as recently accessed + * + * This routine should be called every so often to ensure that the socket + * files have a recent mod date (ordinary operations on sockets usually won't + * change the mod date). That saves them from being removed by + * overenthusiastic /tmp-directory-cleaner daemons. (Another reason we should + * never have put the socket file in /tmp...) + */ +void +TouchSocketFiles(void) +{ + ListCell *l; + + /* Loop through all created sockets... */ + foreach(l, sock_paths) + { + char *sock_path = (char *) lfirst(l); + + /* Ignore errors; there's no point in complaining */ + (void) utime(sock_path, NULL); + } +} + +/* + * RemoveSocketFiles -- unlink socket files at postmaster shutdown + */ +void +RemoveSocketFiles(void) +{ + ListCell *l; + + /* Loop through all created sockets... */ + foreach(l, sock_paths) + { + char *sock_path = (char *) lfirst(l); + + /* Ignore any error. */ + (void) unlink(sock_path); + } + /* Since we're about to exit, no need to reclaim storage */ + sock_paths = NIL; +} + + +/* -------------------------------- + * Low-level I/O routines begin here. + * + * These routines communicate with a frontend client across a connection + * already established by the preceding routines. + * -------------------------------- + */ + +/* -------------------------------- + * socket_set_nonblocking - set socket blocking/non-blocking + * + * Sets the socket non-blocking if nonblocking is true, or sets it + * blocking otherwise. + * -------------------------------- + */ +static void +socket_set_nonblocking(bool nonblocking) +{ + if (MyProcPort == NULL) + ereport(ERROR, + (errcode(ERRCODE_CONNECTION_DOES_NOT_EXIST), + errmsg("there is no client connection"))); + + MyProcPort->noblock = nonblocking; +} + +/* -------------------------------- + * pq_recvbuf - load some bytes into the input buffer + * + * returns 0 if OK, EOF if trouble + * -------------------------------- + */ +static int +pq_recvbuf(void) +{ + if (PqRecvPointer > 0) + { + if (PqRecvLength > PqRecvPointer) + { + /* still some unread data, left-justify it in the buffer */ + memmove(PqRecvBuffer, PqRecvBuffer + PqRecvPointer, + PqRecvLength - PqRecvPointer); + PqRecvLength -= PqRecvPointer; + PqRecvPointer = 0; + } + else + PqRecvLength = PqRecvPointer = 0; + } + + /* Ensure that we're in blocking mode */ + socket_set_nonblocking(false); + + /* Can fill buffer from PqRecvLength and upwards */ + for (;;) + { + int r; + + r = secure_read(MyProcPort, PqRecvBuffer + PqRecvLength, + PQ_RECV_BUFFER_SIZE - PqRecvLength); + + if (r < 0) + { + if (errno == EINTR) + continue; /* Ok if interrupted */ + + /* + * Careful: an ereport() that tries to write to the client would + * cause recursion to here, leading to stack overflow and core + * dump! This message must go *only* to the postmaster log. + */ + ereport(COMMERROR, + (errcode_for_socket_access(), + errmsg("could not receive data from client: %m"))); + return EOF; + } + if (r == 0) + { + /* + * EOF detected. We used to write a log message here, but it's + * better to expect the ultimate caller to do that. + */ + return EOF; + } + /* r contains number of bytes read, so just incr length */ + PqRecvLength += r; + return 0; + } +} + +/* -------------------------------- + * pq_getbyte - get a single byte from connection, or return EOF + * -------------------------------- + */ +int +pq_getbyte(void) +{ + Assert(PqCommReadingMsg); + + while (PqRecvPointer >= PqRecvLength) + { + if (pq_recvbuf()) /* If nothing in buffer, then recv some */ + return EOF; /* Failed to recv data */ + } + return (unsigned char) PqRecvBuffer[PqRecvPointer++]; +} + +/* -------------------------------- + * pq_peekbyte - peek at next byte from connection + * + * Same as pq_getbyte() except we don't advance the pointer. + * -------------------------------- + */ +int +pq_peekbyte(void) +{ + Assert(PqCommReadingMsg); + + while (PqRecvPointer >= PqRecvLength) + { + if (pq_recvbuf()) /* If nothing in buffer, then recv some */ + return EOF; /* Failed to recv data */ + } + return (unsigned char) PqRecvBuffer[PqRecvPointer]; +} + +/* -------------------------------- + * pq_getbyte_if_available - get a single byte from connection, + * if available + * + * The received byte is stored in *c. Returns 1 if a byte was read, + * 0 if no data was available, or EOF if trouble. + * -------------------------------- + */ +int +pq_getbyte_if_available(unsigned char *c) +{ + int r; + + Assert(PqCommReadingMsg); + + if (PqRecvPointer < PqRecvLength) + { + *c = PqRecvBuffer[PqRecvPointer++]; + return 1; + } + + /* Put the socket into non-blocking mode */ + socket_set_nonblocking(true); + + r = secure_read(MyProcPort, c, 1); + if (r < 0) + { + /* + * Ok if no data available without blocking or interrupted (though + * EINTR really shouldn't happen with a non-blocking socket). Report + * other errors. + */ + if (errno == EAGAIN || errno == EWOULDBLOCK || errno == EINTR) + r = 0; + else + { + /* + * Careful: an ereport() that tries to write to the client would + * cause recursion to here, leading to stack overflow and core + * dump! This message must go *only* to the postmaster log. + */ + ereport(COMMERROR, + (errcode_for_socket_access(), + errmsg("could not receive data from client: %m"))); + r = EOF; + } + } + else if (r == 0) + { + /* EOF detected */ + r = EOF; + } + + return r; +} + +/* -------------------------------- + * pq_getbytes - get a known number of bytes from connection + * + * returns 0 if OK, EOF if trouble + * -------------------------------- + */ +int +pq_getbytes(char *s, size_t len) +{ + size_t amount; + + Assert(PqCommReadingMsg); + + while (len > 0) + { + while (PqRecvPointer >= PqRecvLength) + { + if (pq_recvbuf()) /* If nothing in buffer, then recv some */ + return EOF; /* Failed to recv data */ + } + amount = PqRecvLength - PqRecvPointer; + if (amount > len) + amount = len; + memcpy(s, PqRecvBuffer + PqRecvPointer, amount); + PqRecvPointer += amount; + s += amount; + len -= amount; + } + return 0; +} + +/* -------------------------------- + * pq_discardbytes - throw away a known number of bytes + * + * same as pq_getbytes except we do not copy the data to anyplace. + * this is used for resynchronizing after read errors. + * + * returns 0 if OK, EOF if trouble + * -------------------------------- + */ +static int +pq_discardbytes(size_t len) +{ + size_t amount; + + Assert(PqCommReadingMsg); + + while (len > 0) + { + while (PqRecvPointer >= PqRecvLength) + { + if (pq_recvbuf()) /* If nothing in buffer, then recv some */ + return EOF; /* Failed to recv data */ + } + amount = PqRecvLength - PqRecvPointer; + if (amount > len) + amount = len; + PqRecvPointer += amount; + len -= amount; + } + return 0; +} + +/* -------------------------------- + * pq_buffer_has_data - is any buffered data available to read? + * + * This will *not* attempt to read more data. + * -------------------------------- + */ +bool +pq_buffer_has_data(void) +{ + return (PqRecvPointer < PqRecvLength); +} + + +/* -------------------------------- + * pq_startmsgread - begin reading a message from the client. + * + * This must be called before any of the pq_get* functions. + * -------------------------------- + */ +void +pq_startmsgread(void) +{ + /* + * There shouldn't be a read active already, but let's check just to be + * sure. + */ + if (PqCommReadingMsg) + ereport(FATAL, + (errcode(ERRCODE_PROTOCOL_VIOLATION), + errmsg("terminating connection because protocol synchronization was lost"))); + + PqCommReadingMsg = true; +} + + +/* -------------------------------- + * pq_endmsgread - finish reading message. + * + * This must be called after reading a message with pq_getbytes() + * and friends, to indicate that we have read the whole message. + * pq_getmessage() does this implicitly. + * -------------------------------- + */ +void +pq_endmsgread(void) +{ + Assert(PqCommReadingMsg); + + PqCommReadingMsg = false; +} + +/* -------------------------------- + * pq_is_reading_msg - are we currently reading a message? + * + * This is used in error recovery at the outer idle loop to detect if we have + * lost protocol sync, and need to terminate the connection. pq_startmsgread() + * will check for that too, but it's nicer to detect it earlier. + * -------------------------------- + */ +bool +pq_is_reading_msg(void) +{ + return PqCommReadingMsg; +} + +/* -------------------------------- + * pq_getmessage - get a message with length word from connection + * + * The return value is placed in an expansible StringInfo, which has + * already been initialized by the caller. + * Only the message body is placed in the StringInfo; the length word + * is removed. Also, s->cursor is initialized to zero for convenience + * in scanning the message contents. + * + * maxlen is the upper limit on the length of the + * message we are willing to accept. We abort the connection (by + * returning EOF) if client tries to send more than that. + * + * returns 0 if OK, EOF if trouble + * -------------------------------- + */ +int +pq_getmessage(StringInfo s, int maxlen) +{ + int32 len; + + Assert(PqCommReadingMsg); + + resetStringInfo(s); + + /* Read message length word */ + if (pq_getbytes((char *) &len, 4) == EOF) + { + ereport(COMMERROR, + (errcode(ERRCODE_PROTOCOL_VIOLATION), + errmsg("unexpected EOF within message length word"))); + return EOF; + } + + len = pg_ntoh32(len); + + if (len < 4 || len > maxlen) + { + ereport(COMMERROR, + (errcode(ERRCODE_PROTOCOL_VIOLATION), + errmsg("invalid message length"))); + return EOF; + } + + len -= 4; /* discount length itself */ + + if (len > 0) + { + /* + * Allocate space for message. If we run out of room (ridiculously + * large message), we will elog(ERROR), but we want to discard the + * message body so as not to lose communication sync. + */ + PG_TRY(); + { + enlargeStringInfo(s, len); + } + PG_CATCH(); + { + if (pq_discardbytes(len) == EOF) + ereport(COMMERROR, + (errcode(ERRCODE_PROTOCOL_VIOLATION), + errmsg("incomplete message from client"))); + + /* we discarded the rest of the message so we're back in sync. */ + PqCommReadingMsg = false; + PG_RE_THROW(); + } + PG_END_TRY(); + + /* And grab the message */ + if (pq_getbytes(s->data, len) == EOF) + { + ereport(COMMERROR, + (errcode(ERRCODE_PROTOCOL_VIOLATION), + errmsg("incomplete message from client"))); + return EOF; + } + s->len = len; + /* Place a trailing null per StringInfo convention */ + s->data[len] = '\0'; + } + + /* finished reading the message. */ + PqCommReadingMsg = false; + + return 0; +} + + +static int +internal_putbytes(const char *s, size_t len) +{ + size_t amount; + + while (len > 0) + { + /* If buffer is full, then flush it out */ + if (PqSendPointer >= PqSendBufferSize) + { + socket_set_nonblocking(false); + if (internal_flush()) + return EOF; + } + amount = PqSendBufferSize - PqSendPointer; + if (amount > len) + amount = len; + memcpy(PqSendBuffer + PqSendPointer, s, amount); + PqSendPointer += amount; + s += amount; + len -= amount; + } + return 0; +} + +/* -------------------------------- + * socket_flush - flush pending output + * + * returns 0 if OK, EOF if trouble + * -------------------------------- + */ +static int +socket_flush(void) +{ + int res; + + /* No-op if reentrant call */ + if (PqCommBusy) + return 0; + PqCommBusy = true; + socket_set_nonblocking(false); + res = internal_flush(); + PqCommBusy = false; + return res; +} + +/* -------------------------------- + * internal_flush - flush pending output + * + * Returns 0 if OK (meaning everything was sent, or operation would block + * and the socket is in non-blocking mode), or EOF if trouble. + * -------------------------------- + */ +static int +internal_flush(void) +{ + static int last_reported_send_errno = 0; + + char *bufptr = PqSendBuffer + PqSendStart; + char *bufend = PqSendBuffer + PqSendPointer; + + while (bufptr < bufend) + { + int r; + + r = secure_write(MyProcPort, bufptr, bufend - bufptr); + + if (r <= 0) + { + if (errno == EINTR) + continue; /* Ok if we were interrupted */ + + /* + * Ok if no data writable without blocking, and the socket is in + * non-blocking mode. + */ + if (errno == EAGAIN || + errno == EWOULDBLOCK) + { + return 0; + } + + /* + * Careful: an ereport() that tries to write to the client would + * cause recursion to here, leading to stack overflow and core + * dump! This message must go *only* to the postmaster log. + * + * If a client disconnects while we're in the midst of output, we + * might write quite a bit of data before we get to a safe query + * abort point. So, suppress duplicate log messages. + */ + if (errno != last_reported_send_errno) + { + last_reported_send_errno = errno; + ereport(COMMERROR, + (errcode_for_socket_access(), + errmsg("could not send data to client: %m"))); + } + + /* + * We drop the buffered data anyway so that processing can + * continue, even though we'll probably quit soon. We also set a + * flag that'll cause the next CHECK_FOR_INTERRUPTS to terminate + * the connection. + */ + PqSendStart = PqSendPointer = 0; + ClientConnectionLost = 1; + InterruptPending = 1; + return EOF; + } + + last_reported_send_errno = 0; /* reset after any successful send */ + bufptr += r; + PqSendStart += r; + } + + PqSendStart = PqSendPointer = 0; + return 0; +} + +/* -------------------------------- + * pq_flush_if_writable - flush pending output if writable without blocking + * + * Returns 0 if OK, or EOF if trouble. + * -------------------------------- + */ +static int +socket_flush_if_writable(void) +{ + int res; + + /* Quick exit if nothing to do */ + if (PqSendPointer == PqSendStart) + return 0; + + /* No-op if reentrant call */ + if (PqCommBusy) + return 0; + + /* Temporarily put the socket into non-blocking mode */ + socket_set_nonblocking(true); + + PqCommBusy = true; + res = internal_flush(); + PqCommBusy = false; + return res; +} + +/* -------------------------------- + * socket_is_send_pending - is there any pending data in the output buffer? + * -------------------------------- + */ +static bool +socket_is_send_pending(void) +{ + return (PqSendStart < PqSendPointer); +} + +/* -------------------------------- + * Message-level I/O routines begin here. + * -------------------------------- + */ + + +/* -------------------------------- + * socket_putmessage - send a normal message (suppressed in COPY OUT mode) + * + * msgtype is a message type code to place before the message body. + * + * len is the length of the message body data at *s. A message length + * word (equal to len+4 because it counts itself too) is inserted by this + * routine. + * + * We suppress messages generated while pqcomm.c is busy. This + * avoids any possibility of messages being inserted within other + * messages. The only known trouble case arises if SIGQUIT occurs + * during a pqcomm.c routine --- quickdie() will try to send a warning + * message, and the most reasonable approach seems to be to drop it. + * + * returns 0 if OK, EOF if trouble + * -------------------------------- + */ +static int +socket_putmessage(char msgtype, const char *s, size_t len) +{ + uint32 n32; + + Assert(msgtype != 0); + + if (PqCommBusy) + return 0; + PqCommBusy = true; + if (internal_putbytes(&msgtype, 1)) + goto fail; + + n32 = pg_hton32((uint32) (len + 4)); + if (internal_putbytes((char *) &n32, 4)) + goto fail; + + if (internal_putbytes(s, len)) + goto fail; + PqCommBusy = false; + return 0; + +fail: + PqCommBusy = false; + return EOF; +} + +/* -------------------------------- + * pq_putmessage_noblock - like pq_putmessage, but never blocks + * + * If the output buffer is too small to hold the message, the buffer + * is enlarged. + */ +static void +socket_putmessage_noblock(char msgtype, const char *s, size_t len) +{ + int res PG_USED_FOR_ASSERTS_ONLY; + int required; + + /* + * Ensure we have enough space in the output buffer for the message header + * as well as the message itself. + */ + required = PqSendPointer + 1 + 4 + len; + if (required > PqSendBufferSize) + { + PqSendBuffer = repalloc(PqSendBuffer, required); + PqSendBufferSize = required; + } + res = pq_putmessage(msgtype, s, len); + Assert(res == 0); /* should not fail when the message fits in + * buffer */ +} + +/* -------------------------------- + * pq_putmessage_v2 - send a message in protocol version 2 + * + * msgtype is a message type code to place before the message body. + * + * We no longer support protocol version 2, but we have kept this + * function so that if a client tries to connect with protocol version 2, + * as a courtesy we can still send the "unsupported protocol version" + * error to the client in the old format. + * + * Like in pq_putmessage(), we suppress messages generated while + * pqcomm.c is busy. + * + * returns 0 if OK, EOF if trouble + * -------------------------------- + */ +int +pq_putmessage_v2(char msgtype, const char *s, size_t len) +{ + Assert(msgtype != 0); + + if (PqCommBusy) + return 0; + PqCommBusy = true; + if (internal_putbytes(&msgtype, 1)) + goto fail; + + if (internal_putbytes(s, len)) + goto fail; + PqCommBusy = false; + return 0; + +fail: + PqCommBusy = false; + return EOF; +} + +/* + * Support for TCP Keepalive parameters + */ + +/* + * On Windows, we need to set both idle and interval at the same time. + * We also cannot reset them to the default (setting to zero will + * actually set them to zero, not default), therefore we fallback to + * the out-of-the-box default instead. + */ +#if defined(WIN32) && defined(SIO_KEEPALIVE_VALS) +static int +pq_setkeepaliveswin32(Port *port, int idle, int interval) +{ + struct tcp_keepalive ka; + DWORD retsize; + + if (idle <= 0) + idle = 2 * 60 * 60; /* default = 2 hours */ + if (interval <= 0) + interval = 1; /* default = 1 second */ + + ka.onoff = 1; + ka.keepalivetime = idle * 1000; + ka.keepaliveinterval = interval * 1000; + + if (WSAIoctl(port->sock, + SIO_KEEPALIVE_VALS, + (LPVOID) &ka, + sizeof(ka), + NULL, + 0, + &retsize, + NULL, + NULL) + != 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: error code %d", + "WSAIoctl", "SIO_KEEPALIVE_VALS", WSAGetLastError()))); + return STATUS_ERROR; + } + if (port->keepalives_idle != idle) + port->keepalives_idle = idle; + if (port->keepalives_interval != interval) + port->keepalives_interval = interval; + return STATUS_OK; +} +#endif + +int +pq_getkeepalivesidle(Port *port) +{ +#if defined(PG_TCP_KEEPALIVE_IDLE) || defined(SIO_KEEPALIVE_VALS) + if (port == NULL || port->laddr.addr.ss_family == AF_UNIX) + return 0; + + if (port->keepalives_idle != 0) + return port->keepalives_idle; + + if (port->default_keepalives_idle == 0) + { +#ifndef WIN32 + socklen_t size = sizeof(port->default_keepalives_idle); + + if (getsockopt(port->sock, IPPROTO_TCP, PG_TCP_KEEPALIVE_IDLE, + (char *) &port->default_keepalives_idle, + &size) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "getsockopt", PG_TCP_KEEPALIVE_IDLE_STR))); + port->default_keepalives_idle = -1; /* don't know */ + } +#else /* WIN32 */ + /* We can't get the defaults on Windows, so return "don't know" */ + port->default_keepalives_idle = -1; +#endif /* WIN32 */ + } + + return port->default_keepalives_idle; +#else + return 0; +#endif +} + +int +pq_setkeepalivesidle(int idle, Port *port) +{ + if (port == NULL || port->laddr.addr.ss_family == AF_UNIX) + return STATUS_OK; + +/* check SIO_KEEPALIVE_VALS here, not just WIN32, as some toolchains lack it */ +#if defined(PG_TCP_KEEPALIVE_IDLE) || defined(SIO_KEEPALIVE_VALS) + if (idle == port->keepalives_idle) + return STATUS_OK; + +#ifndef WIN32 + if (port->default_keepalives_idle <= 0) + { + if (pq_getkeepalivesidle(port) < 0) + { + if (idle == 0) + return STATUS_OK; /* default is set but unknown */ + else + return STATUS_ERROR; + } + } + + if (idle == 0) + idle = port->default_keepalives_idle; + + if (setsockopt(port->sock, IPPROTO_TCP, PG_TCP_KEEPALIVE_IDLE, + (char *) &idle, sizeof(idle)) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "setsockopt", PG_TCP_KEEPALIVE_IDLE_STR))); + return STATUS_ERROR; + } + + port->keepalives_idle = idle; +#else /* WIN32 */ + return pq_setkeepaliveswin32(port, idle, port->keepalives_interval); +#endif +#else + if (idle != 0) + { + ereport(LOG, + (errmsg("setting the keepalive idle time is not supported"))); + return STATUS_ERROR; + } +#endif + + return STATUS_OK; +} + +int +pq_getkeepalivesinterval(Port *port) +{ +#if defined(TCP_KEEPINTVL) || defined(SIO_KEEPALIVE_VALS) + if (port == NULL || port->laddr.addr.ss_family == AF_UNIX) + return 0; + + if (port->keepalives_interval != 0) + return port->keepalives_interval; + + if (port->default_keepalives_interval == 0) + { +#ifndef WIN32 + socklen_t size = sizeof(port->default_keepalives_interval); + + if (getsockopt(port->sock, IPPROTO_TCP, TCP_KEEPINTVL, + (char *) &port->default_keepalives_interval, + &size) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "getsockopt", "TCP_KEEPINTVL"))); + port->default_keepalives_interval = -1; /* don't know */ + } +#else + /* We can't get the defaults on Windows, so return "don't know" */ + port->default_keepalives_interval = -1; +#endif /* WIN32 */ + } + + return port->default_keepalives_interval; +#else + return 0; +#endif +} + +int +pq_setkeepalivesinterval(int interval, Port *port) +{ + if (port == NULL || port->laddr.addr.ss_family == AF_UNIX) + return STATUS_OK; + +#if defined(TCP_KEEPINTVL) || defined(SIO_KEEPALIVE_VALS) + if (interval == port->keepalives_interval) + return STATUS_OK; + +#ifndef WIN32 + if (port->default_keepalives_interval <= 0) + { + if (pq_getkeepalivesinterval(port) < 0) + { + if (interval == 0) + return STATUS_OK; /* default is set but unknown */ + else + return STATUS_ERROR; + } + } + + if (interval == 0) + interval = port->default_keepalives_interval; + + if (setsockopt(port->sock, IPPROTO_TCP, TCP_KEEPINTVL, + (char *) &interval, sizeof(interval)) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "setsockopt", "TCP_KEEPINTVL"))); + return STATUS_ERROR; + } + + port->keepalives_interval = interval; +#else /* WIN32 */ + return pq_setkeepaliveswin32(port, port->keepalives_idle, interval); +#endif +#else + if (interval != 0) + { + ereport(LOG, + (errmsg("%s(%s) not supported", "setsockopt", "TCP_KEEPINTVL"))); + return STATUS_ERROR; + } +#endif + + return STATUS_OK; +} + +int +pq_getkeepalivescount(Port *port) +{ +#ifdef TCP_KEEPCNT + if (port == NULL || port->laddr.addr.ss_family == AF_UNIX) + return 0; + + if (port->keepalives_count != 0) + return port->keepalives_count; + + if (port->default_keepalives_count == 0) + { + socklen_t size = sizeof(port->default_keepalives_count); + + if (getsockopt(port->sock, IPPROTO_TCP, TCP_KEEPCNT, + (char *) &port->default_keepalives_count, + &size) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "getsockopt", "TCP_KEEPCNT"))); + port->default_keepalives_count = -1; /* don't know */ + } + } + + return port->default_keepalives_count; +#else + return 0; +#endif +} + +int +pq_setkeepalivescount(int count, Port *port) +{ + if (port == NULL || port->laddr.addr.ss_family == AF_UNIX) + return STATUS_OK; + +#ifdef TCP_KEEPCNT + if (count == port->keepalives_count) + return STATUS_OK; + + if (port->default_keepalives_count <= 0) + { + if (pq_getkeepalivescount(port) < 0) + { + if (count == 0) + return STATUS_OK; /* default is set but unknown */ + else + return STATUS_ERROR; + } + } + + if (count == 0) + count = port->default_keepalives_count; + + if (setsockopt(port->sock, IPPROTO_TCP, TCP_KEEPCNT, + (char *) &count, sizeof(count)) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "setsockopt", "TCP_KEEPCNT"))); + return STATUS_ERROR; + } + + port->keepalives_count = count; +#else + if (count != 0) + { + ereport(LOG, + (errmsg("%s(%s) not supported", "setsockopt", "TCP_KEEPCNT"))); + return STATUS_ERROR; + } +#endif + + return STATUS_OK; +} + +int +pq_gettcpusertimeout(Port *port) +{ +#ifdef TCP_USER_TIMEOUT + if (port == NULL || port->laddr.addr.ss_family == AF_UNIX) + return 0; + + if (port->tcp_user_timeout != 0) + return port->tcp_user_timeout; + + if (port->default_tcp_user_timeout == 0) + { + socklen_t size = sizeof(port->default_tcp_user_timeout); + + if (getsockopt(port->sock, IPPROTO_TCP, TCP_USER_TIMEOUT, + (char *) &port->default_tcp_user_timeout, + &size) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "getsockopt", "TCP_USER_TIMEOUT"))); + port->default_tcp_user_timeout = -1; /* don't know */ + } + } + + return port->default_tcp_user_timeout; +#else + return 0; +#endif +} + +int +pq_settcpusertimeout(int timeout, Port *port) +{ + if (port == NULL || port->laddr.addr.ss_family == AF_UNIX) + return STATUS_OK; + +#ifdef TCP_USER_TIMEOUT + if (timeout == port->tcp_user_timeout) + return STATUS_OK; + + if (port->default_tcp_user_timeout <= 0) + { + if (pq_gettcpusertimeout(port) < 0) + { + if (timeout == 0) + return STATUS_OK; /* default is set but unknown */ + else + return STATUS_ERROR; + } + } + + if (timeout == 0) + timeout = port->default_tcp_user_timeout; + + if (setsockopt(port->sock, IPPROTO_TCP, TCP_USER_TIMEOUT, + (char *) &timeout, sizeof(timeout)) < 0) + { + ereport(LOG, + (errmsg("%s(%s) failed: %m", "setsockopt", "TCP_USER_TIMEOUT"))); + return STATUS_ERROR; + } + + port->tcp_user_timeout = timeout; +#else + if (timeout != 0) + { + ereport(LOG, + (errmsg("%s(%s) not supported", "setsockopt", "TCP_USER_TIMEOUT"))); + return STATUS_ERROR; + } +#endif + + return STATUS_OK; +} + +/* + * Check if the client is still connected. + */ +bool +pq_check_connection(void) +{ + WaitEvent events[FeBeWaitSetNEvents]; + int rc; + + /* + * It's OK to modify the socket event filter without restoring, because + * all FeBeWaitSet socket wait sites do the same. + */ + ModifyWaitEvent(FeBeWaitSet, FeBeWaitSetSocketPos, WL_SOCKET_CLOSED, NULL); + +retry: + rc = WaitEventSetWait(FeBeWaitSet, 0, events, lengthof(events), 0); + for (int i = 0; i < rc; ++i) + { + if (events[i].events & WL_SOCKET_CLOSED) + return false; + if (events[i].events & WL_LATCH_SET) + { + /* + * A latch event might be preventing other events from being + * reported. Reset it and poll again. No need to restore it + * because no code should expect latches to survive across + * CHECK_FOR_INTERRUPTS(). + */ + ResetLatch(MyLatch); + goto retry; + } + } + + return true; +} |