glibc/misc/daemon.c

 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)
31static 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
43int
44daemon(nochdir, noclose)
45        int nochdir, noclose;
46{
47        int fd;
48
49        switch (__fork()) {
50        case -1:
51                return (-1);
52        case 0:
53                break;
54        default:
55                _exit(0);
56        }
57
58        if (__setsid() == -1)
59                return (-1);
60
61        if (!nochdir)
62                (void)__chdir("/");
63
64        if (!noclose) {
65                struct stat64 st;
66
67                if ((fd = open_not_cancel(_PATH_DEVNULL, O_RDWR, 0)) != -1
68                    && (__builtin_expect (__fxstat64 (_STAT_VER, fd, &st), 0)
69                        == 0)) {
70                        if (__builtin_expect (S_ISCHR (st.st_mode), 1) != 0
71#if defined DEV_NULL_MAJOR && defined DEV_NULL_MINOR
72                            && (st.st_rdev
73                                == makedev (DEV_NULL_MAJOR, DEV_NULL_MINOR))
74#endif
75                            ) {
76                                (void)__dup2(fd, STDIN_FILENO);
77                                (void)__dup2(fd, STDOUT_FILENO);
78                                (void)__dup2(fd, STDERR_FILENO);
79                                if (fd > 2)
80                                        (void)__close (fd);
81                        } else {
82                                /* We must set an errno value since no
83                                   function call actually failed.  */
84                                close_not_cancel_no_status (fd);
85                                __set_errno (ENODEV);
86                                return -1;
87                        }
88                } else {
89                        close_not_cancel_no_status (fd);
90                        return -1;
91                }
92        }
93        return (0);
94}
95