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 3 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU 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, see <http://www.gnu.org/licenses/>.
18 /** @file server/daemonize.c
19 * @brief Go into background
22 #include "disorder-server.h"
24 /** @brief Go into background
25 * @param tag Message tag, or NULL
26 * @param fac Logging facility
27 * @param pidfile Where to store PID, or NULL
29 * Become a daemon. stdout/stderr are lost and DisOrder's logging is
30 * redirected to syslog. It is assumed that there are no FDs beyond 2
33 void daemonize(const char *tag, int fac, const char *pidfile) {
38 D(("daemonize tag=%s fac=%d pidfile=%s",
39 tag ? tag : "NULL", fac, pidfile ? pidfile : "NULL"));
40 /* make sure that FDs 0, 1, 2 all at least exist (and get a
43 if((dn = open("/dev/null", O_RDWR, 0)) < 0)
44 disorder_fatal(errno, "error opening /dev/null");
48 /* Parent process. Wait for the first child to finish, then
49 * return to the caller. */
51 while((r = waitpid(pid, &w, 0)) == -1 && errno == EINTR)
53 if(r < 0) disorder_fatal(errno, "error calling waitpid");
55 disorder_error(0, "subprocess exited with wait status %#x", (unsigned)w);
58 /* First child process. This will be the session leader, and will
60 D(("first child pid=%lu", (unsigned long)getpid()));
62 disorder_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 disorder_fatal(errno, "error creating %s", pidfile);