| /* |
| * 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) 1996-2009, PostgreSQL Global Development Group |
| * |
| * IDENTIFICATION |
| * $PostgreSQL: pgsql/src/backend/postmaster/fork_process.c,v 1.9 2009/01/01 17:23:46 momjian Exp $ |
| */ |
| #include "postgres.h" |
| #include "postmaster/fork_process.h" |
| |
| #include <time.h> |
| #include <sys/time.h> |
| #include <unistd.h> |
| #ifdef USE_SSL |
| #include <openssl/rand.h> |
| #endif |
| |
| #ifndef WIN32 |
| /* |
| * 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 |
| |
| result = fork(); |
| if (result == 0) |
| { |
| /* fork succeeded, in child */ |
| #ifdef LINUX_PROFILE |
| setitimer(ITIMER_PROF, &prof_itimer, NULL); |
| #endif |
| |
| /* |
| * Make sure processes do not share OpenSSL randomness state. |
| */ |
| #ifdef USE_SSL |
| RAND_cleanup(); |
| #endif |
| |
| } |
| |
| return result; |
| } |
| |
| #endif /* ! WIN32 */ |