xref: /freebsd/lib/libc/gen/daemon.c (revision e4e9813eb92cd7c4d4b819a8fbed5cbd3d92f5d8)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)daemon.c	8.1 (Berkeley) 6/4/93";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include "namespace.h"
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <paths.h>
44 #include <stdlib.h>
45 #include <signal.h>
46 #include <unistd.h>
47 #include "un-namespace.h"
48 
49 int
50 daemon(nochdir, noclose)
51 	int nochdir, noclose;
52 {
53 	struct sigaction osa, sa;
54 	int fd;
55 	pid_t newgrp;
56 	int oerrno;
57 	int osa_ok;
58 
59 	/* A SIGHUP may be thrown when the parent exits below. */
60 	sigemptyset(&sa.sa_mask);
61 	sa.sa_handler = SIG_IGN;
62 	sa.sa_flags = 0;
63 	osa_ok = _sigaction(SIGHUP, &sa, &osa);
64 
65 	switch (fork()) {
66 	case -1:
67 		return (-1);
68 	case 0:
69 		break;
70 	default:
71 		_exit(0);
72 	}
73 
74 	newgrp = setsid();
75 	oerrno = errno;
76 	if (osa_ok != -1)
77 		_sigaction(SIGHUP, &osa, NULL);
78 
79 	if (newgrp == -1) {
80 		errno = oerrno;
81 		return (-1);
82 	}
83 
84 	if (!nochdir)
85 		(void)chdir("/");
86 
87 	if (!noclose && (fd = _open(_PATH_DEVNULL, O_RDWR, 0)) != -1) {
88 		(void)_dup2(fd, STDIN_FILENO);
89 		(void)_dup2(fd, STDOUT_FILENO);
90 		(void)_dup2(fd, STDERR_FILENO);
91 		if (fd > 2)
92 			(void)_close(fd);
93 	}
94 	return (0);
95 }
96