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/*
* fork_process.c
* 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.
*
* Copyright (c) 1996-2005, PostgreSQL Global Development Group
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/fork_process.c,v 1.1 2005/03/10 07:14:03 neilc Exp $
*/
#include "postgres.h"
#include "postmaster/fork_process.h"
#include <unistd.h>
/*
* 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)
{
pid_t result;
#ifdef LINUX_PROFILE
struct itimerval prof_itimer;
#endif
/*
* 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 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
result = fork();
if (result == (pid_t) -1)
{
/* fork failed */
#ifdef __BEOS__
/* Specific beos backend startup actions */
beos_backend_startup_failed();
#endif
}
else if (result == 0)
{
/* fork succeeded, in child */
#ifdef LINUX_PROFILE
setitimer(ITIMER_PROF, &prof_itimer, NULL);
#endif
#ifdef __BEOS__
/* Specific beos backend startup actions */
beos_backend_startup();
#endif
}
return result;
}
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