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 #pragma ident "%Z%%M% %I% %E% SMI"
30
31 /* NFS server */
32
33 #include <sys/param.h>
34 #include <sys/types.h>
35 #include <errno.h>
36 #include <stdio.h>
37 #include <stdio_ext.h>
38 #include <stdlib.h>
39 #include <signal.h>
40 #include <unistd.h>
41 #include <sys/wait.h>
42 #include <sys/stat.h>
43 #include <fcntl.h>
44 #include <libscf.h>
45
46 /*
47 * The parent never returns from this function. It sits
48 * and waits for the child to send status on whether it
49 * loaded or not.
50 *
51 * We do not close down the standard file descriptors until
52 * we know the child is going to run.
53 */
54 int
daemonize_init(void)55 daemonize_init(void)
56 {
57 int status, pfds[2];
58 sigset_t set, oset;
59 pid_t pid;
60
61 /*
62 * Block all signals prior to the fork and leave them blocked in the
63 * parent so we don't get in a situation where the parent gets SIGINT
64 * and returns non-zero exit status and the child is actually running.
65 * In the child, restore the signal mask once we've done our setsid().
66 */
67 (void) sigfillset(&set);
68 (void) sigdelset(&set, SIGABRT);
69 (void) sigprocmask(SIG_BLOCK, &set, &oset);
70
71 /*
72 * We need to do this before we open the pipe - it makes things
73 * easier in the long run.
74 */
75 closefrom(STDERR_FILENO + 1);
76
77 if (pipe(pfds) == -1) {
78 fprintf(stderr, "failed to create pipe for daemonize");
79 exit(SMF_EXIT_ERR_FATAL);
80 }
81
82 if ((pid = fork()) == -1) {
83 fprintf(stderr, "failed to fork into background");
84 exit(SMF_EXIT_ERR_FATAL);
85 }
86
87 if (pid != 0) {
88 (void) close(pfds[1]);
89
90 if (read(pfds[0], &status, sizeof (status)) == sizeof (status))
91 exit(status);
92
93 if (waitpid(pid, &status, 0) == pid && WIFEXITED(status))
94 exit(WEXITSTATUS(status));
95
96 exit(SMF_EXIT_ERR_FATAL);
97 }
98
99 /*
100 * All child from here on...
101 */
102 (void) setsid();
103 (void) sigprocmask(SIG_SETMASK, &oset, NULL);
104 (void) close(pfds[0]);
105
106 return (pfds[1]);
107 }
108
109 /*
110 * We are only a daemon if the file descriptor is valid.
111 */
112 void
daemonize_fini(int fd)113 daemonize_fini(int fd)
114 {
115 int status = 0;
116
117 if (fd != -1) {
118 (void) write(fd, &status, sizeof (status));
119
120 (void) close(fd);
121
122 if ((fd = open("/dev/null", O_RDWR)) >= 0) {
123 (void) fcntl(fd, F_DUP2FD, STDIN_FILENO);
124 (void) fcntl(fd, F_DUP2FD, STDOUT_FILENO);
125 (void) fcntl(fd, F_DUP2FD, STDERR_FILENO);
126 (void) close(fd);
127 }
128 }
129 }
130