460b9539 |
1 | /* |
2 | * This file is part of DisOrder. |
3 | * Copyright (C) 2004, 2005 Richard Kettlewell |
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 | */ |
20 | |
21 | #include <config.h> |
22 | |
23 | #include <fcntl.h> |
24 | #include <unistd.h> |
25 | #include <stdio.h> |
26 | #include <errno.h> |
27 | #include <sys/wait.h> |
28 | #include <syslog.h> |
29 | |
30 | #include "daemonize.h" |
31 | #include "syscalls.h" |
32 | #include "log.h" |
33 | |
34 | void daemonize(const char *tag, int fac, const char *pidfile) { |
35 | pid_t pid, r; |
36 | int w, dn; |
37 | FILE *fp; |
38 | |
39 | D(("daemonize tag=%s fac=%d pidfile=%s", |
40 | tag ? tag : "NULL", fac, pidfile ? pidfile : "NULL")); |
41 | /* make sure that FDs 0, 1, 2 all at least exist (and get a |
42 | * /dev/null) */ |
43 | do { |
44 | if((dn = open("/dev/null", O_RDWR, 0)) < 0) |
45 | fatal(errno, "error opening /dev/null"); |
46 | } while(dn < 3); |
47 | pid = xfork(); |
48 | if(pid) { |
49 | /* Parent process. Wait for the first child to finish, then |
50 | * return to the caller. */ |
51 | exitfn = _exit; |
52 | while((r = waitpid(pid, &w, 0)) == -1 && errno == EINTR) |
53 | ; |
54 | if(r < 0) fatal(errno, "error calling waitpid"); |
55 | if(w) error(0, "subprocess exited with wait status %#x", (unsigned)w); |
56 | _exit(0); |
57 | } |
58 | /* First child process. This will be the session leader, and will |
59 | * be transient. */ |
60 | D(("first child pid=%lu", (unsigned long)getpid())); |
61 | if(setsid() < 0) fatal(errno, "error calling setsid"); |
62 | /* we'll log to syslog */ |
63 | openlog(tag, LOG_PID, fac); |
64 | log_default = &log_syslog; |
65 | /* stdin/out/err we lose */ |
66 | xdup2(dn, 0); |
67 | xdup2(dn, 1); |
68 | xdup2(dn, 2); |
69 | xclose(dn); |
70 | pid = xfork(); |
71 | if(pid) |
72 | _exit(0); |
73 | /* second child. Write a pidfile if someone wanted it. */ |
74 | D(("second child pid=%lu", (unsigned long)getpid())); |
75 | if(pidfile) { |
76 | if(!(fp = fopen(pidfile, "w")) |
77 | || fprintf(fp, "%lu\n", (unsigned long)getpid()) < 0 |
78 | || fclose(fp) < 0) |
79 | fatal(errno, "error creating %s", pidfile); |
80 | } |
81 | } |
82 | |
83 | /* |
84 | Local Variables: |
85 | c-basic-offset:2 |
86 | comment-column:40 |
87 | End: |
88 | */ |