daemon.c revision 1.10 
1/*	$NetBSD: daemon.c,v 1.10 2012/06/25 22:32:43 abs Exp $	*/
2
3/*-
4 * Copyright (c) 1990, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33#if defined(LIBC_SCCS) && !defined(lint)
34#if 0
35static char sccsid[] = "@(#)daemon.c	8.1 (Berkeley) 6/4/93";
36#else
37__RCSID("$NetBSD: daemon.c,v 1.10 2012/06/25 22:32:43 abs Exp $");
38#endif
39#endif /* LIBC_SCCS and not lint */
40
41#include "namespace.h"
42#include <fcntl.h>
43#include <paths.h>
44#include <stdlib.h>
45#include <unistd.h>
46
47#ifdef __weak_alias
48__weak_alias(daemon,_daemon)
49#endif
50
51int
52daemon(int nochdir, int noclose)
53{
54	int fd;
55
56	switch (fork()) {
57	case -1:
58		return (-1);
59	case 0:
60		break;
61	default:
62		_exit(0);
63	}
64
65	if (setsid() == -1)
66		return (-1);
67
68	if (!nochdir)
69		(void)chdir("/");
70
71	if (!noclose && (fd = open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
72		(void)dup2(fd, STDIN_FILENO);
73		(void)dup2(fd, STDOUT_FILENO);
74		(void)dup2(fd, STDERR_FILENO);
75		if (fd > STDERR_FILENO)
76			(void)close(fd);
77	}
78	return (0);
79}
80