1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include "lint.h"
28 #include "file64.h"
29 #include "mtlib.h"
30
31 #include <stdio.h>
32 #include <stdlib.h>
33 #include <unistd.h>
34 #include <fcntl.h>
35
36 #include "stdiom.h"
37
38 /*
39 * Use fork/setsid/fork to go into background and permanently remove
40 * controlling terminal.
41 */
42 int
daemon(int nochdir,int noclose)43 daemon(int nochdir, int noclose)
44 {
45 int retv, fd;
46
47 /*
48 * By the first fork+setsid, we disconnect from our current controlling
49 * terminal and become a session group leader.
50 */
51 retv = fork();
52 if (retv == -1)
53 return (-1);
54 if (retv != 0)
55 _exit(EXIT_SUCCESS);
56 if (setsid() == -1)
57 return (-1);
58 /*
59 * By forking again without calling setsid again, we make certain
60 * that we are not the session group leader and can never reacquire
61 * a controlling terminal.
62 */
63 retv = fork();
64 if (retv == -1)
65 return (-1);
66 if (retv != 0)
67 _exit(EXIT_SUCCESS);
68
69 if (nochdir == 0)
70 (void) chdir("/");
71
72 if (noclose == 0) {
73 /*
74 * Missing the PRIV_FILE_READ privilege may be one of the
75 * reasons that prevent the opening of /dev/null to succeed.
76 */
77 if ((fd = open("/dev/null", O_RDWR)) == -1)
78 return (-1);
79
80 /*
81 * Also, if any of the descriptor redirects fails we should
82 * return with error to signal to the caller that his request
83 * cannot be fulfilled properly. It is up to the caller to
84 * do the cleanup.
85 */
86 if ((fd != STDIN_FILENO) && (dup2(fd, STDIN_FILENO) < 0)) {
87 (void) close(fd);
88 return (-1);
89 }
90 if ((fd != STDOUT_FILENO) && (dup2(fd, STDOUT_FILENO) < 0)) {
91 (void) close(fd);
92 return (-1);
93 }
94 if ((fd != STDERR_FILENO) && (dup2(fd, STDERR_FILENO) < 0)) {
95 (void) close(fd);
96 return (-1);
97 }
98
99 if (fd > STDERR_FILENO)
100 (void) close(fd);
101 }
102 return (0);
103 }
104