xref: /freebsd/usr.sbin/daemon/daemon.c (revision d056fa046c6a91b90cd98165face0e42a33a5173)
1 /*-
2  * Copyright (c) 1999 Berkeley Software Design, Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1. Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2. Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  * 3. Berkeley Software Design Inc's name may not be used to endorse or
13  *    promote products derived from this software without specific prior
14  *    written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  *	From BSDI: daemon.c,v 1.2 1996/08/15 01:11:09 jch Exp
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include <sys/param.h>
35 
36 #include <err.h>
37 #include <errno.h>
38 #include <libutil.h>
39 #include <stdio.h>
40 #include <stdlib.h>
41 #include <unistd.h>
42 
43 static void usage(void);
44 
45 int
46 main(int argc, char *argv[])
47 {
48 	struct pidfh *pfh;
49 	int ch, nochdir, noclose, errcode;
50 	const char *pidfile;
51 	pid_t otherpid;
52 
53 	nochdir = noclose = 1;
54 	pidfile = NULL;
55 	while ((ch = getopt(argc, argv, "-cfp:")) != -1) {
56 		switch (ch) {
57 		case 'c':
58 			nochdir = 0;
59 			break;
60 		case 'f':
61 			noclose = 0;
62 			break;
63 		case 'p':
64 			pidfile = optarg;
65 			break;
66 		default:
67 			usage();
68 		}
69 	}
70 	argc -= optind;
71 	argv += optind;
72 
73 	if (argc == 0)
74 		usage();
75 	/*
76 	 * Try to open the pidfile before calling daemon(3),
77 	 * to be able to report the error intelligently
78 	 */
79 	if (pidfile) {
80 		pfh = pidfile_open(pidfile, 0600, &otherpid);
81 		if (pfh == NULL) {
82 			if (errno == EEXIST) {
83 				errx(3, "process already running, pid: %d",
84 				    otherpid);
85 			}
86 			err(2, "pidfile ``%s''", pidfile);
87 		}
88 	}
89 
90 	if (daemon(nochdir, noclose) == -1)
91 		err(1, NULL);
92 
93 	/* Now that we are the child, write out the pid */
94 	if (pidfile)
95 		pidfile_write(pfh);
96 
97 	execvp(argv[0], argv);
98 
99 	/*
100 	 * execvp() failed -- unlink pidfile if any, and
101 	 * report the error
102 	 */
103 	errcode = errno; /* Preserve errcode -- unlink may reset it */
104 	if (pidfile)
105 		pidfile_remove(pfh);
106 
107 	/* The child is now running, so the exit status doesn't matter. */
108 	errc(1, errcode, "%s", argv[0]);
109 }
110 
111 static void
112 usage(void)
113 {
114 	(void)fprintf(stderr,
115 	    "usage: daemon [-cf] [-p pidfile] command arguments ...\n");
116 	exit(1);
117 }
118