1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993 The Regents of the University of California.
5 * Copyright (c) 2017 Mariusz Zaborski <oshogbo@FreeBSD.org>
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include "namespace.h"
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <paths.h>
37 #include <stdlib.h>
38 #include <signal.h>
39 #include <unistd.h>
40 #include "un-namespace.h"
41 #include "libc_private.h"
42
43 int
daemonfd(int chdirfd,int nullfd)44 daemonfd(int chdirfd, int nullfd)
45 {
46 struct sigaction osa, sa;
47 pid_t newgrp;
48 int oerrno;
49 int osa_ok;
50
51 /* A SIGHUP may be thrown when the parent exits below. */
52 sigemptyset(&sa.sa_mask);
53 sa.sa_handler = SIG_IGN;
54 sa.sa_flags = 0;
55 osa_ok = __libc_sigaction(SIGHUP, &sa, &osa);
56
57 switch (fork()) {
58 case -1:
59 return (-1);
60 case 0:
61 break;
62 default:
63 /*
64 * A fine point: _exit(0), not exit(0), to avoid triggering
65 * atexit(3) processing
66 */
67 _exit(0);
68 }
69
70 newgrp = setsid();
71 oerrno = errno;
72 if (osa_ok != -1)
73 __libc_sigaction(SIGHUP, &osa, NULL);
74
75 if (newgrp == -1) {
76 errno = oerrno;
77 return (-1);
78 }
79
80 if (chdirfd != -1)
81 (void)fchdir(chdirfd);
82
83 if (nullfd != -1) {
84 (void)_dup2(nullfd, STDIN_FILENO);
85 (void)_dup2(nullfd, STDOUT_FILENO);
86 (void)_dup2(nullfd, STDERR_FILENO);
87 }
88 return (0);
89 }
90
91 int
daemon(int nochdir,int noclose)92 daemon(int nochdir, int noclose)
93 {
94 int chdirfd, nullfd, ret;
95
96 if (!noclose)
97 nullfd = _open(_PATH_DEVNULL, O_RDWR, 0);
98 else
99 nullfd = -1;
100
101 if (!nochdir)
102 chdirfd = _open("/", O_EXEC);
103 else
104 chdirfd = -1;
105
106 ret = daemonfd(chdirfd, nullfd);
107
108 if (chdirfd != -1)
109 _close(chdirfd);
110
111 if (nullfd > 2)
112 _close(nullfd);
113
114 return (ret);
115 }
116