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Refactor fork()-related code. We need to do various housekeeping tasks

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before we can invoke fork() -- flush stdio buffers, save and restore the
profiling timer on Linux with LINUX_PROFILE, and handle BeOS stuff. This
patch moves that code into a single function, fork_process(), instead of
duplicating it at the various callsites of fork().

This patch doesn't address the EXEC_BACKEND case; there is room for
further cleanup there.
This commit is contained in:
Neil Conway
2005-03-10 07:14:03 +00:00
parent e829f82223
commit 164adc4d39
7 changed files with 108 additions and 151 deletions
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120
src/backend/postmaster/postmaster.c
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@@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.445 2005/02/22 04:36:36 momjian Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.446 2005/03/10 07:14:03 neilc Exp $
*
* NOTES
*
@@ -92,6 +92,8 @@
#include <DNSServiceDiscovery/DNSServiceDiscovery.h>
#endif
#include "access/xlog.h"
#include "bootstrap/bootstrap.h"
#include "catalog/pg_control.h"
#include "catalog/pg_database.h"
#include "commands/async.h"
@@ -103,23 +105,22 @@
#include "libpq/pqsignal.h"
#include "miscadmin.h"
#include "nodes/nodes.h"
#include "postmaster/postmaster.h"
#include "pgstat.h"
#include "postmaster/fork_process.h"
#include "postmaster/pgarch.h"
#include "postmaster/postmaster.h"
#include "postmaster/syslogger.h"
#include "storage/bufmgr.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/pg_shmem.h"
#include "storage/pmsignal.h"
#include "storage/proc.h"
#include "storage/bufmgr.h"
#include "access/xlog.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/guc.h"
#include "utils/memutils.h"
#include "utils/ps_status.h"
#include "bootstrap/bootstrap.h"
#include "pgstat.h"
#ifdef EXEC_BACKEND
#include "storage/spin.h"
@@ -1008,16 +1009,7 @@ pmdaemonize(void)
int i;
pid_t pid;
#ifdef LINUX_PROFILE
struct itimerval prof_itimer;
#endif
#ifdef LINUX_PROFILE
/* see comments in BackendStartup */
getitimer(ITIMER_PROF, &prof_itimer);
#endif
pid = fork();
pid = fork_process();
if (pid == (pid_t) -1)
{
write_stderr("%s: could not fork background process: %s\n",
@@ -1030,10 +1022,6 @@ pmdaemonize(void)
_exit(0);
}
#ifdef LINUX_PROFILE
setitimer(ITIMER_PROF, &prof_itimer, NULL);
#endif
MyProcPid = PostmasterPid = getpid(); /* reset PID vars to child */
/* GH: If there's no setsid(), we hopefully don't need silent mode.
@@ -2382,10 +2370,6 @@ BackendStartup(Port *port)
Backend *bn; /* for backend cleanup */
pid_t pid;
#ifdef LINUX_PROFILE
struct itimerval prof_itimer;
#endif
/*
* Compute the cancel key that will be assigned to this backend. The
* backend will have its own copy in the forked-off process' value of
@@ -2409,54 +2393,13 @@ BackendStartup(Port *port)
/* Pass down canAcceptConnections state (kluge for EXEC_BACKEND case) */
port->canAcceptConnections = canAcceptConnections();
/*
* Flush stdio channels just before fork, to avoid double-output
* problems. Ideally we'd use fflush(NULL) here, but there are still a
* few non-ANSI stdio libraries out there (like SunOS 4.1.x) that
* coredump if we do. Presently stdout and stderr are the only stdio
* output channels used by the postmaster, so fflush'ing them should
* be sufficient.
*/
fflush(stdout);
fflush(stderr);
#ifdef EXEC_BACKEND
pid = backend_forkexec(port);
#else /* !EXEC_BACKEND */
#ifdef LINUX_PROFILE
/*
* Linux's fork() resets the profiling timer in the child process. If
* we want to profile child processes then we need to save and restore
* the timer setting. This is a waste of time if not profiling,
* however, so only do it if commanded by specific -DLINUX_PROFILE
* switch.
*/
getitimer(ITIMER_PROF, &prof_itimer);
#endif
#ifdef __BEOS__
/* Specific beos actions before backend startup */
beos_before_backend_startup();
#endif
pid = fork();
pid = fork_process();
if (pid == 0) /* child */
{
#ifdef LINUX_PROFILE
setitimer(ITIMER_PROF, &prof_itimer, NULL);
#endif
#ifdef __BEOS__
/* Specific beos backend startup actions */
beos_backend_startup();
#endif
free(bn);
proc_exit(BackendRun(port));
}
#endif /* EXEC_BACKEND */
@@ -2466,10 +2409,6 @@ BackendStartup(Port *port)
/* in parent, fork failed */
int save_errno = errno;
#ifdef __BEOS__
/* Specific beos backend startup actions */
beos_backend_startup_failed();
#endif
free(bn);
errno = save_errno;
ereport(LOG,
@@ -2945,7 +2884,7 @@ internal_forkexec(int argc, char *argv[], Port *port)
argv[2] = tmpfilename;
/* Fire off execv in child */
if ((pid = fork()) == 0)
if ((pid = fork_process()) == 0)
{
if (execv(postgres_exec_path, argv) < 0)
{
@@ -3465,10 +3404,6 @@ StartChildProcess(int xlop)
int ac = 0;
char xlbuf[32];
#ifdef LINUX_PROFILE
struct itimerval prof_itimer;
#endif
/*
* Set up command-line arguments for subprocess
*/
@@ -3488,41 +3423,13 @@ StartChildProcess(int xlop)
av[ac] = NULL;
Assert(ac < lengthof(av));
/*
* Flush stdio channels (see comments in BackendStartup)
*/
fflush(stdout);
fflush(stderr);
#ifdef EXEC_BACKEND
pid = postmaster_forkexec(ac, av);
#else /* !EXEC_BACKEND */
#ifdef LINUX_PROFILE
/* see comments in BackendStartup */
getitimer(ITIMER_PROF, &prof_itimer);
#endif
#ifdef __BEOS__
/* Specific beos actions before backend startup */
beos_before_backend_startup();
#endif
pid = fork();
pid = fork_process();
if (pid == 0) /* child */
{
#ifdef LINUX_PROFILE
setitimer(ITIMER_PROF, &prof_itimer, NULL);
#endif
#ifdef __BEOS__
/* Specific beos actions after backend startup */
beos_backend_startup();
#endif
IsUnderPostmaster = true; /* we are a postmaster subprocess
* now */
@@ -3546,11 +3453,6 @@ StartChildProcess(int xlop)
{
/* in parent, fork failed */
int save_errno = errno;
#ifdef __BEOS__
/* Specific beos actions before backend startup */
beos_backend_startup_failed();
#endif
errno = save_errno;
switch (xlop)
{