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  * 4. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  */
29 
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static char sccsid[] = "@(#)daemon.c	8.1 (Berkeley) 6/4/93";
32 #endif /* LIBC_SCCS and not lint */
33 
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <paths.h>
37 #include <unistd.h>
38 #include <sys/stat.h>
39 
40 #include <device-nrs.h>
41 #include <not-cancel.h>
42 
43 int
daemon(int nochdir,int noclose)44 daemon (int nochdir, int noclose)
45 {
46 	int fd;
47 
48 	switch (__fork()) {
49 	case -1:
50 		return (-1);
51 	case 0:
52 		break;
53 	default:
54 		_exit(0);
55 	}
56 
57 	if (__setsid() == -1)
58 		return (-1);
59 
60 	if (!nochdir)
61 		(void)__chdir("/");
62 
63 	if (!noclose) {
64 		struct stat64 st;
65 
66 		if ((fd = __open_nocancel(_PATH_DEVNULL, O_RDWR, 0)) != -1
67 		    && (__builtin_expect (__fstat64 (fd, &st), 0)
68 			== 0)) {
69 			if (__builtin_expect (S_ISCHR (st.st_mode), 1) != 0
70 #if defined DEV_NULL_MAJOR && defined DEV_NULL_MINOR
71 			    && (st.st_rdev
72 				== makedev (DEV_NULL_MAJOR, DEV_NULL_MINOR))
73 #endif
74 			    ) {
75 				(void)__dup2(fd, STDIN_FILENO);
76 				(void)__dup2(fd, STDOUT_FILENO);
77 				(void)__dup2(fd, STDERR_FILENO);
78 				if (fd > 2)
79 					(void)__close (fd);
80 			} else {
81 				/* We must set an errno value since no
82 				   function call actually failed.  */
83 				__close_nocancel_nostatus (fd);
84 				__set_errno (ENODEV);
85 				return -1;
86 			}
87 		} else {
88 			__close_nocancel_nostatus (fd);
89 			return -1;
90 		}
91 	}
92 	return (0);
93 }
94