2 * This file is part of DisOrder.
3 * Copyright (C) 2004, 2005, 2007, 2008 Richard Kettlewell
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.
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.
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
20 /** @file server/daemonize.c
21 * @brief Go into background
24 #include "disorder-server.h"
26 /** @brief Go into background
27 * @param tag Message tag, or NULL
28 * @param fac Logging facility
29 * @param pidfile Where to store PID, or NULL
31 * Become a daemon. stdout/stderr are lost and DisOrder's logging is
32 * redirected to syslog. It is assumed that there are no FDs beyond 2
35 void daemonize(const char *tag, int fac, const char *pidfile) {
40 D(("daemonize tag=%s fac=%d pidfile=%s",
41 tag ? tag : "NULL", fac, pidfile ? pidfile : "NULL"));
42 /* make sure that FDs 0, 1, 2 all at least exist (and get a
45 if((dn = open("/dev/null", O_RDWR, 0)) < 0)
46 fatal(errno, "error opening /dev/null");
50 /* Parent process. Wait for the first child to finish, then
51 * return to the caller. */
53 while((r = waitpid(pid, &w, 0)) == -1 && errno == EINTR)
55 if(r < 0) fatal(errno, "error calling waitpid");
56 if(w) error(0, "subprocess exited with wait status %#x", (unsigned)w);
59 /* First child process. This will be the session leader, and will
61 D(("first child pid=%lu", (unsigned long)getpid()));
62 if(setsid() < 0) fatal(errno, "error calling setsid");
63 /* we'll log to syslog */
64 openlog(tag, LOG_PID, fac);
65 log_default = &log_syslog;
66 /* stdin/out/err we lose */
74 /* second child. Write a pidfile if someone wanted it. */
75 D(("second child pid=%lu", (unsigned long)getpid()));
77 if(!(fp = fopen(pidfile, "w"))
78 || fprintf(fp, "%lu\n", (unsigned long)getpid()) < 0
80 fatal(errno, "error creating %s", pidfile);