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 * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /* LINTLIBRARY */
27 /* PROTOLIB1 */
28
29 /* NFS server */
30
31 #include <sys/param.h>
32 #include <sys/types.h>
33 #include <errno.h>
34 #include <stdio.h>
35 #include <stdio_ext.h>
36 #include <stdlib.h>
37 #include <signal.h>
38 #include <unistd.h>
39 #include <sys/wait.h>
40 #include <sys/stat.h>
41 #include <fcntl.h>
42 #include <libscf.h>
43
44 /*
45 * The parent never returns from this function. It sits
46 * and waits for the child to send status on whether it
47 * loaded or not.
48 *
49 * We do not close down the standard file descriptors until
50 * we know the child is going to run.
51 */
52 int
daemonize_init(void)53 daemonize_init(void)
54 {
55 int status, pfds[2];
56 sigset_t set, oset;
57 pid_t pid;
58
59 /*
60 * Block all signals prior to the fork and leave them blocked in the
61 * parent so we don't get in a situation where the parent gets SIGINT
62 * and returns non-zero exit status and the child is actually running.
63 * In the child, restore the signal mask once we've done our setsid().
64 */
65 (void) sigfillset(&set);
66 (void) sigdelset(&set, SIGABRT);
67 (void) sigprocmask(SIG_BLOCK, &set, &oset);
68
69 /*
70 * We need to do this before we open the pipe - it makes things
71 * easier in the long run.
72 */
73 closefrom(STDERR_FILENO + 1);
74
75 if (pipe(pfds) == -1) {
76 fprintf(stderr, "failed to create pipe for daemonize");
77 exit(SMF_EXIT_ERR_FATAL);
78 }
79
80 if ((pid = fork()) == -1) {
81 fprintf(stderr, "failed to fork into background");
82 exit(SMF_EXIT_ERR_FATAL);
83 }
84
85 if (pid != 0) {
86 (void) close(pfds[1]);
87
88 if (read(pfds[0], &status, sizeof (status)) == sizeof (status))
89 exit(status);
90
91 if (waitpid(pid, &status, 0) == pid && WIFEXITED(status))
92 exit(WEXITSTATUS(status));
93
94 exit(SMF_EXIT_ERR_FATAL);
95 }
96
97 /*
98 * All child from here on...
99 */
100 (void) setsid();
101 (void) sigprocmask(SIG_SETMASK, &oset, NULL);
102 (void) close(pfds[0]);
103
104 return (pfds[1]);
105 }
106
107 /*
108 * We are only a daemon if the file descriptor is valid.
109 */
110 void
daemonize_fini(int fd)111 daemonize_fini(int fd)
112 {
113 int status = 0;
114
115 if (fd != -1) {
116 (void) write(fd, &status, sizeof (status));
117
118 (void) close(fd);
119
120 if ((fd = open("/dev/null", O_RDWR)) >= 0) {
121 (void) fcntl(fd, F_DUP2FD, STDIN_FILENO);
122 (void) fcntl(fd, F_DUP2FD, STDOUT_FILENO);
123 (void) fcntl(fd, F_DUP2FD, STDERR_FILENO);
124 (void) close(fd);
125 }
126 }
127 }
128