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postgresql/src/backend/libpq/pqcomm.c

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/*-------------------------------------------------------------------------
*
* 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) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* src/backend/libpq/pqcomm.c
*
*-------------------------------------------------------------------------
*/
/*------------------------
* INTERFACE ROUTINES
*
* setup/teardown:
* ListenServerPort - Open postmaster's server port
* AcceptConnection - Accept new connection with client
* 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>
#include <netinet/tcp.h>
#include <utime.h>
#ifdef WIN32
#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_hooks.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 size_t PqSendPointer; /* Next index to store a byte in PqSendBuffer */
static size_t 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 inline int internal_putbytes(const char *s, size_t len);
static inline int internal_flush(void);
static pg_noinline int internal_flush_buffer(const char *buf, size_t *start,
size_t *end);
static int Lock_AF_UNIX(const char *unixSocketDir, const char *unixSocketPath);
static int Setup_AF_UNIX(const char *sock_path);
static const PQcommMethods PqCommSocketMethods = {
.comm_reset = socket_comm_reset,
.flush = socket_flush,
.flush_if_writable = socket_flush_if_writable,
.is_send_pending = socket_is_send_pending,
.putmessage = socket_putmessage,
.putmessage_noblock = socket_putmessage_noblock
};
const PQcommMethods *PqCommMethods = &PqCommSocketMethods;
WaitEventSet *FeBeWaitSet;
/* --------------------------------
* pq_init - initialize libpq at backend startup
* --------------------------------
*/
Port *
pq_init(ClientSocket *client_sock)
{
Port *port;
int socket_pos PG_USED_FOR_ASSERTS_ONLY;
int latch_pos PG_USED_FOR_ASSERTS_ONLY;
/* allocate the Port struct and copy the ClientSocket contents to it */
port = palloc0(sizeof(Port));
port->sock = client_sock->sock;
memcpy(&port->raddr.addr, &client_sock->raddr.addr, client_sock->raddr.salen);
port->raddr.salen = client_sock->raddr.salen;
/* 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(FATAL,
(errmsg("%s() failed: %m", "getsockname")));
}
/* 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(FATAL,
(errmsg("%s(%s) failed: %m", "setsockopt", "TCP_NODELAY")));
}
#endif
on = 1;
if (setsockopt(port->sock, SOL_SOCKET, SO_KEEPALIVE,
(char *) &on, sizeof(on)) < 0)
{
ereport(FATAL,
(errmsg("%s(%s) failed: %m", "setsockopt", "SO_KEEPALIVE")));
}
#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(FATAL,
(errmsg("%s(%s) failed: %m", "getsockopt", "SO_SNDBUF")));
}
newopt = PQ_SEND_BUFFER_SIZE * 4;
if (oldopt < newopt)
{
if (setsockopt(port->sock, SOL_SOCKET, SO_SNDBUF, (char *) &newopt,
sizeof(newopt)) < 0)
{
ereport(FATAL,
(errmsg("%s(%s) failed: %m", "setsockopt", "SO_SNDBUF")));
}
}
#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);
}
/* 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.
*/
#ifndef WIN32
if (!pg_set_noblock(port->sock))
ereport(FATAL,
(errmsg("could not set socket to nonblocking mode: %m")));
#endif
#ifndef WIN32
/* Don't give the socket to any subprograms we execute. */
if (fcntl(port->sock, F_SETFD, FD_CLOEXEC) < 0)
elog(FATAL, "fcntl(F_SETFD) failed on socket: %m");
#endif
FeBeWaitSet = CreateWaitEventSet(NULL, FeBeWaitSetNEvents);
socket_pos = AddWaitEventToSet(FeBeWaitSet, WL_SOCKET_WRITEABLE,
port->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);
return port;
}
/* --------------------------------
* 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;
}
}
/* --------------------------------
* Postmaster functions to handle sockets.
* --------------------------------
*/
/*
* ListenServerPort -- 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 appended to the ListenSockets[] array. On
* entry, *NumListenSockets holds the number of elements currently in the
* array, and it is updated to reflect the opened sockets. MaxListen is the
* allocated size of the array.
*
* RETURNS: STATUS_OK or STATUS_ERROR
*/
int
ListenServerPort(int family, const char *hostName, unsigned short portNumber,
const char *unixSocketDir,
pgsocket ListenSockets[], int *NumListenSockets, 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 added = 0;
char unixSocketPath[MAXPGPATH];
#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;
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
{
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. */
if (*NumListenSockets == 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;
case AF_INET6:
familyDesc = _("IPv6");
break;
case AF_UNIX:
familyDesc = _("Unix");
break;
default:
snprintf(familyDescBuf, sizeof(familyDescBuf),
_("unrecognized address family %d"),
addr->ai_family);
familyDesc = familyDescBuf;
break;
}
/* set up text form of address for log messages */
if (addr->ai_family == AF_UNIX)
addrDesc = unixSocketPath;
else
{
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
/* Don't give the listen socket to any subprograms we execute. */
if (fcntl(fd, F_SETFD, FD_CLOEXEC) < 0)
elog(FATAL, "fcntl(F_SETFD) failed on socket: %m");
/*
* 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;
}
if (addr->ai_family == AF_UNIX)
{
if (Setup_AF_UNIX(service) != STATUS_OK)
{
closesocket(fd);
break;
}
}
/*
* Select appropriate accept-queue length limit. It seems reasonable
* to use a value similar to the maximum number of child processes
* that the postmaster will permit.
*/
maxconn = MaxConnections * 2;
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;
}
if (addr->ai_family == AF_UNIX)
ereport(LOG,
(errmsg("listening on Unix socket \"%s\"",
addrDesc)));
else
ereport(LOG,
/* translator: first %s is IPv4 or IPv6 */
(errmsg("listening on %s address \"%s\", port %d",
familyDesc, addrDesc, (int) portNumber)));
ListenSockets[*NumListenSockets] = fd;
(*NumListenSockets)++;
added++;
}
pg_freeaddrinfo_all(hint.ai_family, addrs);
if (!added)
return STATUS_ERROR;
return STATUS_OK;
}
/*
* 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;
}
/*
* AcceptConnection -- accept a new connection with client using
* server port. Fills *client_sock with the FD and endpoint info
* of the new connection.
*
* ASSUME: that this doesn't need to be non-blocking because
* the Postmaster waits for the socket to be ready to accept().
*
* RETURNS: STATUS_OK or STATUS_ERROR
*/
int
AcceptConnection(pgsocket server_fd, ClientSocket *client_sock)
{
/* accept connection and fill in the client (remote) address */
client_sock->raddr.salen = sizeof(client_sock->raddr.addr);
if ((client_sock->sock = accept(server_fd,
(struct sockaddr *) &client_sock->raddr.addr,
&client_sock->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;
}
return STATUS_OK;
}
/*
* 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;
errno = 0;
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.
*
* If errno is zero, assume it's EOF and let the caller complain.
*/
if (errno != 0)
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);
errno = 0;
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.
*
* If errno is zero, assume it's EOF and let the caller complain.
*/
if (errno != 0)
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_remaining_data - return number of bytes in receive buffer
*
* This will *not* attempt to read more data. And reading up to that number of
* bytes should not cause reading any more data either.
* --------------------------------
*/
ssize_t
pq_buffer_remaining_data(void)
{
Assert(PqRecvLength >= PqRecvPointer);
return (PqRecvLength - PqRecvPointer);
}
/* --------------------------------
* 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 inline int
internal_putbytes(const char *s, size_t len)
{
while (len > 0)
{
/* If buffer is full, then flush it out */
if (PqSendPointer >= PqSendBufferSize)
{
socket_set_nonblocking(false);
if (internal_flush())
return EOF;
}
/*
* If the buffer is empty and data length is larger than the buffer
* size, send it without buffering. Otherwise, copy as much data as
* possible into the buffer.
*/
if (len >= PqSendBufferSize && PqSendStart == PqSendPointer)
{
size_t start = 0;
socket_set_nonblocking(false);
if (internal_flush_buffer(s, &start, &len))
return EOF;
}
else
{
size_t 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 inline int
internal_flush(void)
{
return internal_flush_buffer(PqSendBuffer, &PqSendStart, &PqSendPointer);
}
/* --------------------------------
* internal_flush_buffer - flush the given buffer content
*
* 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 pg_noinline int
internal_flush_buffer(const char *buf, size_t *start, size_t *end)
{
static int last_reported_send_errno = 0;
const char *bufptr = buf + *start;
const char *bufend = buf + *end;
while (bufptr < bufend)
{
int r;
r = secure_write(MyProcPort, (char *) 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.
*/
*start = *end = 0;
ClientConnectionLost = 1;
InterruptPending = 1;
return EOF;
}
last_reported_send_errno = 0; /* reset after any successful send */
bufptr += r;
*start += r;
}
*start = *end = 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;
}
/*
* GUC assign_hook for tcp_keepalives_idle
*/
void
assign_tcp_keepalives_idle(int newval, void *extra)
{
/*
* The kernel API provides no way to test a value without setting it; and
* once we set it we might fail to unset it. So there seems little point
* in fully implementing the check-then-assign GUC API for these
* variables. Instead we just do the assignment on demand.
* pq_setkeepalivesidle reports any problems via ereport(LOG).
*
* This approach means that the GUC value might have little to do with the
* actual kernel value, so we use a show_hook that retrieves the kernel
* value rather than trusting GUC's copy.
*/
(void) pq_setkeepalivesidle(newval, MyProcPort);
}
/*
* GUC show_hook for tcp_keepalives_idle
*/
const char *
show_tcp_keepalives_idle(void)
{
/* See comments in assign_tcp_keepalives_idle */
static char nbuf[16];
snprintf(nbuf, sizeof(nbuf), "%d", pq_getkeepalivesidle(MyProcPort));
return nbuf;
}
/*
* GUC assign_hook for tcp_keepalives_interval
*/
void
assign_tcp_keepalives_interval(int newval, void *extra)
{
/* See comments in assign_tcp_keepalives_idle */
(void) pq_setkeepalivesinterval(newval, MyProcPort);
}
/*
* GUC show_hook for tcp_keepalives_interval
*/
const char *
show_tcp_keepalives_interval(void)
{
/* See comments in assign_tcp_keepalives_idle */
static char nbuf[16];
snprintf(nbuf, sizeof(nbuf), "%d", pq_getkeepalivesinterval(MyProcPort));
return nbuf;
}
/*
* GUC assign_hook for tcp_keepalives_count
*/
void
assign_tcp_keepalives_count(int newval, void *extra)
{
/* See comments in assign_tcp_keepalives_idle */
(void) pq_setkeepalivescount(newval, MyProcPort);
}
/*
* GUC show_hook for tcp_keepalives_count
*/
const char *
show_tcp_keepalives_count(void)
{
/* See comments in assign_tcp_keepalives_idle */
static char nbuf[16];
snprintf(nbuf, sizeof(nbuf), "%d", pq_getkeepalivescount(MyProcPort));
return nbuf;
}
/*
* GUC assign_hook for tcp_user_timeout
*/
void
assign_tcp_user_timeout(int newval, void *extra)
{
/* See comments in assign_tcp_keepalives_idle */
(void) pq_settcpusertimeout(newval, MyProcPort);
}
/*
* GUC show_hook for tcp_user_timeout
*/
const char *
show_tcp_user_timeout(void)
{
/* See comments in assign_tcp_keepalives_idle */
static char nbuf[16];
snprintf(nbuf, sizeof(nbuf), "%d", pq_gettcpusertimeout(MyProcPort));
return nbuf;
}
/*
* 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;
}
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