Commit | Line | Data |
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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 | 46 | void 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 | /* | |
96 | Local Variables: | |
97 | c-basic-offset:2 | |
98 | comment-column:40 | |
99 | End: | |
100 | */ |