xref: /freebsd/usr.sbin/daemon/daemon.c (revision cf02bf2407cb217c99cc82f78b7a2e7f0703c9ee)
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/types.h>
35 
36 #include <err.h>
37 #include <errno.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 #include <unistd.h>
41 
42 static void usage(void);
43 
44 int
45 main(int argc, char *argv[])
46 {
47 	int ch, nochdir, noclose, errcode;
48 	FILE *pidf;
49 	const char *pidfile;
50 
51 	nochdir = noclose = 1;
52 	pidfile = NULL;
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 		default:
65 			usage();
66 		}
67 	}
68 	argc -= optind;
69 	argv += optind;
70 
71 	if (argc == 0)
72 		usage();
73 	/*
74 	 * Try to open the pidfile before calling daemon(3),
75 	 * to be able to report the error intelligently
76 	 */
77 	if (pidfile) {
78 		pidf = fopen(pidfile, "w");
79 		if (pidf == NULL)
80 			err(2, "pidfile ``%s''", pidfile);
81 	}
82 
83 	if (daemon(nochdir, noclose) == -1)
84 		err(1, NULL);
85 
86 	/* Now that we are the child, write out the pid */
87 	if (pidfile) {
88 		fprintf(pidf, "%lu\n", (unsigned long)getpid());
89 		fclose(pidf);
90 	}
91 
92 	execvp(argv[0], argv);
93 
94 	/*
95 	 * execvp() failed -- unlink pidfile if any, and
96 	 * report the error
97 	 */
98 	errcode = errno; /* Preserve errcode -- unlink may reset it */
99 	if (pidfile)
100 		unlink(pidfile);
101 
102 	/* The child is now running, so the exit status doesn't matter. */
103 	errc(1, errcode, "%s", argv[0]);
104 }
105 
106 static void
107 usage(void)
108 {
109 	(void)fprintf(stderr,
110 	    "usage: daemon [-cf] [-p pidfile] command arguments ...\n");
111 	exit(1);
112 }
113