daemon.c revision 149424 
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 149424 2005-08-24 17:24:39Z pjd $");
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
43static void usage(void);
44
45int
46main(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
111static void
112usage(void)
113{
114	(void)fprintf(stderr,
115	    "usage: daemon [-cf] [-p pidfile] command arguments ...\n");
116	exit(1);
117}
118