chiark / gitweb /
split out dcgi_get_cookie
[disorder] / server / daemonize.c
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460b9539 1/*
2 * This file is part of DisOrder.
5aff007d 3 * Copyright (C) 2004, 2005, 2007, 2008 Richard Kettlewell
460b9539 4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
18 * USA
19 */
0590cedc
RK
20/** @file server/daemonize.c
21 * @brief Go into background
22 */
460b9539 23
24#include <config.h>
25
26#include <fcntl.h>
27#include <unistd.h>
28#include <stdio.h>
29#include <errno.h>
30#include <sys/wait.h>
31#include <syslog.h>
32
33#include "daemonize.h"
34#include "syscalls.h"
35#include "log.h"
36
0590cedc
RK
37/** @brief Go into background
38 * @param tag Message tag, or NULL
39 * @param fac Logging facility
40 * @param pidfile Where to store PID, or NULL
41 *
42 * Become a daemon. stdout/stderr are lost and DisOrder's logging is
43 * redirected to syslog. It is assumed that there are no FDs beyond 2
44 * that need closing.
45 */
460b9539 46void daemonize(const char *tag, int fac, const char *pidfile) {
47 pid_t pid, r;
48 int w, dn;
49 FILE *fp;
50
51 D(("daemonize tag=%s fac=%d pidfile=%s",
52 tag ? tag : "NULL", fac, pidfile ? pidfile : "NULL"));
53 /* make sure that FDs 0, 1, 2 all at least exist (and get a
54 * /dev/null) */
55 do {
56 if((dn = open("/dev/null", O_RDWR, 0)) < 0)
57 fatal(errno, "error opening /dev/null");
58 } while(dn < 3);
59 pid = xfork();
60 if(pid) {
61 /* Parent process. Wait for the first child to finish, then
62 * return to the caller. */
63 exitfn = _exit;
64 while((r = waitpid(pid, &w, 0)) == -1 && errno == EINTR)
65 ;
66 if(r < 0) fatal(errno, "error calling waitpid");
67 if(w) error(0, "subprocess exited with wait status %#x", (unsigned)w);
68 _exit(0);
69 }
70 /* First child process. This will be the session leader, and will
71 * be transient. */
72 D(("first child pid=%lu", (unsigned long)getpid()));
73 if(setsid() < 0) fatal(errno, "error calling setsid");
74 /* we'll log to syslog */
75 openlog(tag, LOG_PID, fac);
76 log_default = &log_syslog;
77 /* stdin/out/err we lose */
78 xdup2(dn, 0);
79 xdup2(dn, 1);
80 xdup2(dn, 2);
81 xclose(dn);
82 pid = xfork();
83 if(pid)
84 _exit(0);
85 /* second child. Write a pidfile if someone wanted it. */
86 D(("second child pid=%lu", (unsigned long)getpid()));
87 if(pidfile) {
88 if(!(fp = fopen(pidfile, "w"))
89 || fprintf(fp, "%lu\n", (unsigned long)getpid()) < 0
90 || fclose(fp) < 0)
91 fatal(errno, "error creating %s", pidfile);
92 }
93}
94
95/*
96Local Variables:
97c-basic-offset:2
98comment-column:40
99End:
100*/