2005-03-10 08:14:03 +01:00
|
|
|
/*
|
|
|
|
* fork_process.c
|
2005-10-15 04:49:52 +02:00
|
|
|
* A simple wrapper on top of fork(). This does not handle the
|
|
|
|
* EXEC_BACKEND case; it might be extended to do so, but it would be
|
|
|
|
* considerably more complex.
|
2005-03-10 08:14:03 +01:00
|
|
|
*
|
|
|
|
* Copyright (c) 1996-2005, PostgreSQL Global Development Group
|
|
|
|
*
|
|
|
|
* IDENTIFICATION
|
2006-01-05 04:01:38 +01:00
|
|
|
* $PostgreSQL: pgsql/src/backend/postmaster/fork_process.c,v 1.5 2006/01/05 03:01:35 momjian Exp $
|
2005-03-10 08:14:03 +01:00
|
|
|
*/
|
|
|
|
#include "postgres.h"
|
|
|
|
#include "postmaster/fork_process.h"
|
|
|
|
|
2005-03-14 00:27:38 +01:00
|
|
|
#include <time.h>
|
|
|
|
#include <sys/time.h>
|
2005-03-10 08:14:03 +01:00
|
|
|
#include <unistd.h>
|
|
|
|
|
2005-03-16 01:02:39 +01:00
|
|
|
#ifndef WIN32
|
2005-03-10 08:14:03 +01:00
|
|
|
/*
|
|
|
|
* Wrapper for fork(). Return values are the same as those for fork():
|
|
|
|
* -1 if the fork failed, 0 in the child process, and the PID of the
|
|
|
|
* child in the parent process.
|
|
|
|
*/
|
|
|
|
pid_t
|
|
|
|
fork_process(void)
|
|
|
|
{
|
2005-10-15 04:49:52 +02:00
|
|
|
pid_t result;
|
|
|
|
|
2005-03-10 08:14:03 +01:00
|
|
|
#ifdef LINUX_PROFILE
|
|
|
|
struct itimerval prof_itimer;
|
|
|
|
#endif
|
|
|
|
|
|
|
|
/*
|
2005-10-15 04:49:52 +02:00
|
|
|
* 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.
|
2005-03-10 08:14:03 +01:00
|
|
|
*/
|
|
|
|
fflush(stdout);
|
|
|
|
fflush(stderr);
|
|
|
|
|
|
|
|
#ifdef LINUX_PROFILE
|
2005-10-15 04:49:52 +02:00
|
|
|
|
2005-03-10 08:14:03 +01:00
|
|
|
/*
|
2005-10-15 04:49:52 +02:00
|
|
|
* 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.
|
2005-03-10 08:14:03 +01:00
|
|
|
*/
|
|
|
|
getitimer(ITIMER_PROF, &prof_itimer);
|
|
|
|
#endif
|
|
|
|
|
|
|
|
result = fork();
|
2006-01-05 04:01:38 +01:00
|
|
|
if (result == 0)
|
2005-03-10 08:14:03 +01:00
|
|
|
{
|
|
|
|
/* fork succeeded, in child */
|
|
|
|
#ifdef LINUX_PROFILE
|
|
|
|
setitimer(ITIMER_PROF, &prof_itimer, NULL);
|
|
|
|
#endif
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
return result;
|
|
|
|
}
|
2005-10-15 04:49:52 +02:00
|
|
|
|
|
|
|
#endif /* ! WIN32 */
|