xref: /dragonfly/usr.sbin/daemon/daemon.c (revision 6e278935)
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  * $FreeBSD: src/usr.sbin/daemon/daemon.c,v 1.1.2.1 2002/08/28 17:25:54 sheldonh Exp $
30  * $DragonFly: src/usr.sbin/daemon/daemon.c,v 1.4 2004/12/21 23:30:57 liamfoy Exp $
31  */
32 
33 #include <sys/types.h>
34 
35 #include <err.h>
36 #include <errno.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <unistd.h>
40 
41 static void usage(void);
42 
43 int
44 main(int argc, char *argv[])
45 {
46 	int ch, nochdir, noclose, errcode;
47 	FILE *pidf;
48 	const char *pidfile;
49 
50 	nochdir = noclose = 1;
51 	pidfile = NULL;
52 	pidf = 0;
53 	while ((ch = getopt(argc, argv, "cfp:")) != -1) {
54 		switch (ch) {
55 		case 'c':
56 			nochdir = 0;
57 			break;
58 		case 'f':
59 			noclose = 0;
60 			break;
61 		case 'p':
62 			pidfile = optarg;
63 			break;
64 		case '?':
65 		default:
66 			usage();
67 		}
68 	}
69 	argc -= optind;
70 	argv += optind;
71 
72 	if (argc == 0)
73 		usage();
74 
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 		pidf = fopen(pidfile, "w");
81 		if (pidf == NULL)
82 			err(1, "pidfile ``%s''", pidfile);
83 	}
84 
85 	if (daemon(nochdir, noclose) == -1)
86 		err(1, "daemon failed");
87 
88 	/* Now that we are the child, write out the pid */
89 	if (pidfile) {
90 		fprintf(pidf, "%ld\n", (long)getpid());
91 		fclose(pidf);
92 	}
93 
94 	execvp(argv[0], argv);
95 
96 	/*
97 	 * execvp() failed -- unlink pidfile if any, and
98 	 * report the error
99 	 */
100 	errcode = errno; /* Preserve errcode -- unlink may reset it */
101 	if (pidfile)
102 		unlink(pidfile);
103 
104 	/* The child is now running, so the exit status doesn't matter. */
105 	errc(1, errcode, "%s", argv[0]);
106 }
107 
108 static void
109 usage(void)
110 {
111 	fprintf(stderr, "usage: daemon [-cf] [-p pidfile] command arguments ...\n");
112 	exit(1);
113 }
114