mirror of https://github.com/postgres/postgres
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.REL8_1_STABLE
Neil Conway
21 years ago
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e829f82223
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164adc4d39
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/*
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* fork_process.c |
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* A simple wrapper on top of fork(). This does not handle the |
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* EXEC_BACKEND case; it might be extended to do so, but it would be |
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* considerably more complex. |
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* |
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* Copyright (c) 1996-2005, PostgreSQL Global Development Group |
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* |
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* IDENTIFICATION |
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* $PostgreSQL: pgsql/src/backend/postmaster/fork_process.c,v 1.1 2005/03/10 07:14:03 neilc Exp $ |
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*/ |
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#include "postgres.h" |
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#include "postmaster/fork_process.h" |
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#include <unistd.h> |
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/*
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* Wrapper for fork(). Return values are the same as those for fork(): |
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* -1 if the fork failed, 0 in the child process, and the PID of the |
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* child in the parent process. |
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*/ |
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pid_t |
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fork_process(void) |
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{ |
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pid_t result; |
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#ifdef LINUX_PROFILE |
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struct itimerval prof_itimer; |
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#endif |
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/*
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* Flush stdio channels just before fork, to avoid double-output |
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* problems. Ideally we'd use fflush(NULL) here, but there are still a |
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* few non-ANSI stdio libraries out there (like SunOS 4.1.x) that |
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* coredump if we do. Presently stdout and stderr are the only stdio |
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* output channels used by the postmaster, so fflush'ing them should |
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* be sufficient. |
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*/ |
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fflush(stdout); |
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fflush(stderr); |
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#ifdef LINUX_PROFILE |
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/*
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* Linux's fork() resets the profiling timer in the child process. If |
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* we want to profile child processes then we need to save and restore |
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* the timer setting. This is a waste of time if not profiling, |
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* however, so only do it if commanded by specific -DLINUX_PROFILE |
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* switch. |
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*/ |
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getitimer(ITIMER_PROF, &prof_itimer); |
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#endif |
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#ifdef __BEOS__ |
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/* Specific beos actions before backend startup */ |
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beos_before_backend_startup(); |
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#endif |
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result = fork(); |
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if (result == (pid_t) -1) |
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{ |
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/* fork failed */ |
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#ifdef __BEOS__ |
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/* Specific beos backend startup actions */ |
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beos_backend_startup_failed(); |
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#endif |
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} |
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else if (result == 0) |
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{ |
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/* fork succeeded, in child */ |
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#ifdef LINUX_PROFILE |
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setitimer(ITIMER_PROF, &prof_itimer, NULL); |
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#endif |
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#ifdef __BEOS__ |
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/* Specific beos backend startup actions */ |
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beos_backend_startup(); |
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#endif |
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} |
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return result; |
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} |
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@ -0,0 +1,8 @@ |
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#ifndef FORK_PROCESS_H |
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#define FORK_PROCESS_H |
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#include "postgres.h" |
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extern pid_t fork_process(void); |
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#endif /* ! FORK_PROCESS_H */ |
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