daemon.c revision 129983 
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: head/usr.sbin/daemon/daemon.c 129983 2004-06-02 06:48:13Z phk $");
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
42static void usage(void);
43
44int
45main(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
106static void
107usage(void)
108{
109	(void)fprintf(stderr,
110	    "usage: daemon [-cf] [-p pidfile] command arguments ...\n");
111	exit(1);
112}
113