1 /* $OpenBSD: daemon.c,v 1.8 2021/10/24 21:24:20 deraadt Exp $ */
2 /*-
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31 #include <fcntl.h>
32 #include <paths.h>
33 #include <unistd.h>
34 #include <stdlib.h>
35
36 int
daemon(int nochdir,int noclose)37 daemon(int nochdir, int noclose)
38 {
39 int fd;
40
41 switch (fork()) {
42 case -1:
43 return (-1);
44 case 0:
45 break;
46 default:
47 _exit(0);
48 }
49
50 if (setsid() == -1)
51 return (-1);
52
53 if (!nochdir)
54 (void)chdir("/");
55
56 if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR)) != -1) {
57 (void)dup2(fd, STDIN_FILENO);
58 (void)dup2(fd, STDOUT_FILENO);
59 (void)dup2(fd, STDERR_FILENO);
60 if (fd > 2)
61 (void)close(fd);
62 }
63 return (0);
64 }
65