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
36int
37daemon(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