From 1d57374114dadd83bb8428dfa841312568ef3cc4 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 6 Mar 2003 03:16:55 +0000
Subject: [PATCH] Use poll(2) in preference to select(2), if available. This
solves problems in applications that may have a large number of files open,
such that libpq's socket number exceeds the range supported by fd_set. From
Chris Brown.
---
configure | 7 +-
configure.in | 6 +-
src/include/pg_config.h.in | 17 ++-
src/interfaces/libpq/fe-misc.c | 262 ++++++++++++++++++---------------
4 files changed, 167 insertions(+), 125 deletions(-)
diff --git a/configure b/configure
index edc6b5ac87e..4c1b6b1782a 100755
--- a/configure
+++ b/configure
@@ -6888,7 +6888,9 @@ done
-for ac_header in crypt.h dld.h endian.h fp_class.h getopt.h ieeefp.h pwd.h sys/ipc.h sys/pstat.h sys/select.h sys/sem.h sys/socket.h sys/shm.h sys/un.h termios.h utime.h kernel/OS.h kernel/image.h SupportDefs.h
+
+
+for ac_header in crypt.h dld.h endian.h fp_class.h getopt.h ieeefp.h poll.h pwd.h sys/ipc.h sys/poll.h sys/pstat.h sys/select.h sys/sem.h sys/socket.h sys/shm.h sys/un.h termios.h utime.h kernel/OS.h kernel/image.h SupportDefs.h
do
as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
if eval "test \"\${$as_ac_Header+set}\" = set"; then
@@ -10175,7 +10177,8 @@ test $ac_cv_func_memcmp_working = no && LIBOBJS="$LIBOBJS memcmp.$ac_objext"
-for ac_func in cbrt fcvt getpeereid memmove pstat setproctitle setsid sigprocmask sysconf waitpid dlopen fdatasync utime utimes
+
+for ac_func in cbrt dlopen fcvt fdatasync getpeereid memmove poll pstat setproctitle setsid sigprocmask sysconf utime utimes waitpid
do
as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
echo "$as_me:$LINENO: checking for $ac_func" >&5
diff --git a/configure.in b/configure.in
index 77a63434aa4..a79e0107e3b 100644
--- a/configure.in
+++ b/configure.in
@@ -1,5 +1,5 @@
dnl Process this file with autoconf to produce a configure script.
-dnl $Header: /cvsroot/pgsql/configure.in,v 1.237 2003/02/19 04:04:04 momjian Exp $
+dnl $Header: /cvsroot/pgsql/configure.in,v 1.238 2003/03/06 03:16:55 tgl Exp $
dnl
dnl Developers, please strive to achieve this order:
dnl
@@ -675,7 +675,7 @@ fi
##
dnl sys/socket.h is required by AC_FUNC_ACCEPT_ARGTYPES
-AC_CHECK_HEADERS([crypt.h dld.h endian.h fp_class.h getopt.h ieeefp.h pwd.h sys/ipc.h sys/pstat.h sys/select.h sys/sem.h sys/socket.h sys/shm.h sys/un.h termios.h utime.h kernel/OS.h kernel/image.h SupportDefs.h])
+AC_CHECK_HEADERS([crypt.h dld.h endian.h fp_class.h getopt.h ieeefp.h poll.h pwd.h sys/ipc.h sys/poll.h sys/pstat.h sys/select.h sys/sem.h sys/socket.h sys/shm.h sys/un.h termios.h utime.h kernel/OS.h kernel/image.h SupportDefs.h])
# At least on IRIX, cpp test for netinet/tcp.h will fail unless
# netinet/in.h is included first.
@@ -786,7 +786,7 @@ PGAC_FUNC_GETTIMEOFDAY_1ARG
# SunOS doesn't handle negative byte comparisons properly with +/- return
AC_FUNC_MEMCMP
-AC_CHECK_FUNCS([cbrt fcvt getpeereid memmove pstat setproctitle setsid sigprocmask sysconf waitpid dlopen fdatasync utime utimes])
+AC_CHECK_FUNCS([cbrt dlopen fcvt fdatasync getpeereid memmove poll pstat setproctitle setsid sigprocmask sysconf utime utimes waitpid])
AC_CHECK_DECLS(fdatasync, [], [], [#include <unistd.h>])
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index 50960bdfd12..3c8e0b5d507 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -8,7 +8,7 @@
* or in pg_config.h afterwards. Of course, if you edit pg_config.h, then your
* changes will be overwritten the next time you run configure.
*
- * $Id: pg_config.h.in,v 1.40 2003/02/19 04:04:04 momjian Exp $
+ * $Id: pg_config.h.in,v 1.41 2003/03/06 03:16:55 tgl Exp $
*/
#ifndef PG_CONFIG_H
@@ -341,6 +341,12 @@
/* Set to 1 if you have <ieeefp.h> */
#undef HAVE_IEEEFP_H
+/* Set to 1 if you have <poll.h> */
+#undef HAVE_POLL_H
+
+/* Set to 1 if you have <sys/poll.h> */
+#undef HAVE_SYS_POLL_H
+
/* Set to 1 if you have <netinet/tcp.h> */
#undef HAVE_NETINET_TCP_H
@@ -649,6 +655,12 @@
/* Define if you have on_exit() */
#undef HAVE_ON_EXIT
+/* Define if you have syslog() */
+#undef HAVE_SYSLOG
+
+/* Define if you have poll() */
+#undef HAVE_POLL
+
/* Define if the corresponding types are defined in standard headers */
#undef HAVE_INT8
#undef HAVE_UINT8
@@ -656,9 +668,6 @@
#undef HAVE_UINT64
#undef HAVE_SIG_ATOMIC_T
-/* Define if you have syslog() */
-#undef HAVE_SYSLOG
-
/* Define exactly one of these symbols to select semaphore implementation */
#undef USE_NAMED_POSIX_SEMAPHORES
#undef USE_UNNAMED_POSIX_SEMAPHORES
diff --git a/src/interfaces/libpq/fe-misc.c b/src/interfaces/libpq/fe-misc.c
index 2ae1c2630b6..ad99e5de15a 100644
--- a/src/interfaces/libpq/fe-misc.c
+++ b/src/interfaces/libpq/fe-misc.c
@@ -25,7 +25,7 @@
*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-misc.c,v 1.86 2003/01/07 22:23:17 tgl Exp $
+ * $Header: /cvsroot/pgsql/src/interfaces/libpq/fe-misc.c,v 1.87 2003/03/06 03:16:55 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -43,6 +43,12 @@
#include <sys/time.h>
#endif
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#endif
+#ifdef HAVE_SYS_POLL_H
+#include <sys/poll.h>
+#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
@@ -55,6 +61,9 @@
#define DONOTICE(conn,message) \
((*(conn)->noticeHook) ((conn)->noticeArg, (message)))
+static int pqSocketCheck(PGconn *conn, int forRead, int forWrite,
+ time_t end_time);
+static int pqSocketPoll(int sock, int forRead, int forWrite, time_t end_time);
static int pqPutBytes(const char *s, size_t nbytes, PGconn *conn);
@@ -358,40 +367,7 @@ pqPutInt(int value, size_t bytes, PGconn *conn)
int
pqReadReady(PGconn *conn)
{
- fd_set input_mask;
- struct timeval timeout;
-
- if (!conn || conn->sock < 0)
- return -1;
-
-/* JAB: Check for SSL library buffering read bytes */
-#ifdef USE_SSL
- if (conn->ssl && SSL_pending(conn->ssl) > 0)
- {
- /* short-circuit the select */
- return 1;
- }
-#endif
-
-retry1:
- FD_ZERO(&input_mask);
- FD_SET(conn->sock, &input_mask);
- timeout.tv_sec = 0;
- timeout.tv_usec = 0;
- if (select(conn->sock + 1, &input_mask, (fd_set *) NULL, (fd_set *) NULL,
- &timeout) < 0)
- {
- if (SOCK_ERRNO == EINTR)
- /* Interrupted system call - we'll just try again */
- goto retry1;
-
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("select() failed: %s\n"),
- SOCK_STRERROR(SOCK_ERRNO));
- return -1;
- }
-
- return FD_ISSET(conn->sock, &input_mask) ? 1 : 0;
+ return pqSocketCheck(conn, 1, 0, (time_t) 0);
}
/*
@@ -401,30 +377,7 @@ retry1:
int
pqWriteReady(PGconn *conn)
{
- fd_set input_mask;
- struct timeval timeout;
-
- if (!conn || conn->sock < 0)
- return -1;
-
-retry2:
- FD_ZERO(&input_mask);
- FD_SET(conn->sock, &input_mask);
- timeout.tv_sec = 0;
- timeout.tv_usec = 0;
- if (select(conn->sock + 1, (fd_set *) NULL, &input_mask, (fd_set *) NULL,
- &timeout) < 0)
- {
- if (SOCK_ERRNO == EINTR)
- /* Interrupted system call - we'll just try again */
- goto retry2;
-
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("select() failed: %s\n"),
- SOCK_STRERROR(SOCK_ERRNO));
- return -1;
- }
- return FD_ISSET(conn->sock, &input_mask) ? 1 : 0;
+ return pqSocketCheck(conn, 0, 1, (time_t) 0);
}
/* ----------
@@ -785,90 +738,166 @@ pqWait(int forRead, int forWrite, PGconn *conn)
/*
* pqWaitTimed: wait, but not past finish_time.
*
- * If finish_time is exceeded then we return failure (EOF). This is different
- * from the response for a kernel exception (return 0) because we don't want
- * the caller to try to read/write in that case.
+ * If finish_time is exceeded then we return failure (EOF). This is like
+ * the response for a kernel exception because we don't want the caller
+ * to try to read/write in that case.
*
* finish_time = ((time_t) -1) disables the wait limit.
*/
int
pqWaitTimed(int forRead, int forWrite, PGconn *conn, time_t finish_time)
{
- fd_set input_mask;
- fd_set output_mask;
- fd_set except_mask;
- struct timeval tmp_timeout;
- struct timeval *ptmp_timeout = NULL;
- int selresult;
+ int result;
- if (conn->sock < 0)
+ result = pqSocketCheck(conn, forRead, forWrite, finish_time);
+
+ if (result < 0)
+ return EOF; /* errorMessage is already set */
+
+ if (result == 0)
{
printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("connection not open\n"));
+ libpq_gettext("timeout expired\n"));
return EOF;
}
+ return 0;
+}
+
+/*
+ * Checks a socket, using poll or select, for data to be read, written,
+ * or both. Returns >0 if one or more conditions are met, 0 if it timed
+ * out, -1 if an error occurred.
+ * If SSL is in use, the SSL buffer is checked prior to checking the socket
+ * for read data directly.
+ */
+static int
+pqSocketCheck(PGconn *conn, int forRead, int forWrite, time_t end_time)
+{
+ int result;
+
+ if (!conn)
+ return -1;
+ if (conn->sock < 0)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("socket not open\n"));
+ return -1;
+ }
+
/* JAB: Check for SSL library buffering read bytes */
#ifdef USE_SSL
if (forRead && conn->ssl && SSL_pending(conn->ssl) > 0)
{
/* short-circuit the select */
- return 0;
+ return 1;
}
#endif
- if (forRead || forWrite)
+ /* We will retry as long as we get EINTR */
+ do
{
-retry5:
- FD_ZERO(&input_mask);
- FD_ZERO(&output_mask);
- FD_ZERO(&except_mask);
- if (forRead)
- FD_SET(conn->sock, &input_mask);
- if (forWrite)
- FD_SET(conn->sock, &output_mask);
- FD_SET(conn->sock, &except_mask);
-
- if (finish_time != ((time_t) -1))
- {
- /*
- * Set up delay. Assume caller incremented finish_time
- * so that we can error out as soon as time() passes it.
- * Note we will recalculate delay each time through the loop.
- */
- time_t now = time(NULL);
-
- if (finish_time > now)
- tmp_timeout.tv_sec = finish_time - now;
- else
- tmp_timeout.tv_sec = 0;
- tmp_timeout.tv_usec = 0;
- ptmp_timeout = &tmp_timeout;
- }
+ result = pqSocketPoll(conn->sock, forRead, forWrite, end_time);
+ }
+ while (result < 0 && SOCK_ERRNO == EINTR);
- selresult = select(conn->sock + 1, &input_mask, &output_mask,
- &except_mask, ptmp_timeout);
- if (selresult < 0)
- {
- if (SOCK_ERRNO == EINTR)
- goto retry5;
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("select() failed: %s\n"),
- SOCK_STRERROR(SOCK_ERRNO));
- return EOF;
- }
- if (selresult == 0)
- {
- printfPQExpBuffer(&conn->errorMessage,
- libpq_gettext("timeout expired\n"));
- return EOF;
- }
+ if (result < 0)
+ {
+ printfPQExpBuffer(&conn->errorMessage,
+ libpq_gettext("select() failed: %s\n"),
+ SOCK_STRERROR(SOCK_ERRNO));
}
- return 0;
+ return result;
}
+/*
+ * Check a file descriptor for read and/or write data, possibly waiting.
+ * If neither forRead nor forWrite are set, immediately return a timeout
+ * condition (without waiting). Return >0 if condition is met, 0
+ * if a timeout occurred, -1 if an error or interrupt occurred.
+ * Timeout is infinite if end_time is -1. Timeout is immediate (no blocking)
+ * if end_time is 0 (or indeed, any time before now).
+ */
+static int
+pqSocketPoll(int sock, int forRead, int forWrite, time_t end_time)
+{
+ /* We use poll(2) if available, otherwise select(2) */
+#ifdef HAVE_POLL
+ struct pollfd input_fd;
+ int timeout_ms;
+
+ input_fd.fd = sock;
+ input_fd.events = 0;
+ input_fd.revents = 0;
+
+ if (forRead)
+ input_fd.events |= POLLIN;
+ if (forWrite)
+ input_fd.events |= POLLOUT;
+ if (!input_fd.events)
+ return 0;
+
+ /* Compute appropriate timeout interval */
+ if (end_time == ((time_t) -1))
+ {
+ timeout_ms = -1;
+ }
+ else
+ {
+ time_t now = time(NULL);
+
+ if (end_time > now)
+ timeout_ms = (end_time - now) * 1000;
+ else
+ timeout_ms = 0;
+ }
+
+ return poll(&input_fd, 1, timeout_ms);
+
+#else /* !HAVE_POLL */
+
+ fd_set input_mask;
+ fd_set output_mask;
+ fd_set except_mask;
+ struct timeval timeout;
+ struct timeval *ptr_timeout;
+
+ if (!forRead && !forWrite)
+ return 0;
+
+ FD_ZERO(&input_mask);
+ FD_ZERO(&output_mask);
+ FD_ZERO(&except_mask);
+ if (forRead)
+ FD_SET(sock, &input_mask);
+ if (forWrite)
+ FD_SET(sock, &output_mask);
+ FD_SET(sock, &except_mask);
+
+ /* Compute appropriate timeout interval */
+ if (end_time == ((time_t) -1))
+ {
+ ptr_timeout = NULL;
+ }
+ else
+ {
+ time_t now = time(NULL);
+
+ if (end_time > now)
+ timeout.tv_sec = end_time - now;
+ else
+ timeout.tv_sec = 0;
+ timeout.tv_usec = 0;
+ ptr_timeout = &timeout;
+ }
+
+ return select(sock + 1, &input_mask, &output_mask,
+ &except_mask, ptr_timeout);
+#endif /* HAVE_POLL */
+}
+
/*
* A couple of "miscellaneous" multibyte related functions. They used
@@ -902,6 +931,7 @@ PQenv2encoding(void)
#ifdef ENABLE_NLS
+
char *
libpq_gettext(const char *msgid)
{
--
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