xref: /dragonfly/usr.sbin/daemon/daemon.c (revision 678e8cc6)
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  */
31 
32 #include <sys/types.h>
33 
34 #include <err.h>
35 #include <errno.h>
36 #include <stdio.h>
37 #include <stdlib.h>
38 #include <unistd.h>
39 
40 static void usage(void);
41 
42 int
43 main(int argc, char *argv[])
44 {
45 	int ch, nochdir, noclose, errcode;
46 	FILE *pidf;
47 	const char *pidfile;
48 
49 	nochdir = noclose = 1;
50 	pidfile = NULL;
51 	pidf = NULL;
52 	while ((ch = getopt(argc, argv, "cfp:")) != -1) {
53 		switch (ch) {
54 		case 'c':
55 			nochdir = 0;
56 			break;
57 		case 'f':
58 			noclose = 0;
59 			break;
60 		case 'p':
61 			pidfile = optarg;
62 			break;
63 		case '?':
64 		default:
65 			usage();
66 		}
67 	}
68 	argc -= optind;
69 	argv += optind;
70 
71 	if (argc == 0)
72 		usage();
73 
74 	/*
75 	 * Try to open the pidfile before calling daemon(3),
76 	 * to be able to report the error intelligently
77 	 */
78 	if (pidfile) {
79 		pidf = fopen(pidfile, "w");
80 		if (pidf == NULL)
81 			err(1, "pidfile ``%s''", pidfile);
82 	}
83 
84 	if (daemon(nochdir, noclose) == -1)
85 		err(1, "daemon failed");
86 
87 	/* Now that we are the child, write out the pid */
88 	if (pidfile) {
89 		fprintf(pidf, "%ld\n", (long)getpid());
90 		fclose(pidf);
91 	}
92 
93 	execvp(argv[0], argv);
94 
95 	/*
96 	 * execvp() failed -- unlink pidfile if any, and
97 	 * report the error
98 	 */
99 	errcode = errno; /* Preserve errcode -- unlink may reset it */
100 	if (pidfile)
101 		unlink(pidfile);
102 
103 	/* The child is now running, so the exit status doesn't matter. */
104 	errc(1, errcode, "%s", argv[0]);
105 }
106 
107 static void
108 usage(void)
109 {
110 	fprintf(stderr, "usage: daemon [-cf] [-p pidfile] command arguments ...\n");
111 	exit(1);
112 }
113