pidfile.c revision 1.7 
1/*	$OpenBSD: pidfile.c,v 1.7 2005/08/02 21:46:23 espie Exp $	*/
2/*	$NetBSD: pidfile.c,v 1.4 2001/02/19 22:43:42 cgd Exp $	*/
3
4/*-
5 * Copyright (c) 1999 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Jason R. Thorpe.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 *    notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in the
18 *    documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 *    must display the following acknowledgement:
21 *        This product includes software developed by the NetBSD
22 *        Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 *    contributors may be used to endorse or promote products derived
25 *    from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40#include <sys/param.h>
41#include <errno.h>
42#include <paths.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <unistd.h>
46#include <util.h>
47
48static char *pidfile_path;
49static pid_t pidfile_pid;
50
51static void pidfile_cleanup(void);
52
53extern char *__progname;
54
55int
56pidfile(const char *basename)
57{
58	int save_errno;
59	pid_t pid;
60	FILE *f;
61
62	if (basename == NULL)
63		basename = __progname;
64
65	if (pidfile_path != NULL) {
66		free(pidfile_path);
67		pidfile_path = NULL;
68	}
69
70	/* _PATH_VARRUN includes trailing / */
71	(void) asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename);
72	if (pidfile_path == NULL)
73		return (-1);
74
75	if ((f = fopen(pidfile_path, "w")) == NULL) {
76		save_errno = errno;
77		free(pidfile_path);
78		pidfile_path = NULL;
79		errno = save_errno;
80		return (-1);
81	}
82
83	pid = getpid();
84	if (fprintf(f, "%ld\n", (long)pid) <= 0 || fclose(f) != 0) {
85		save_errno = errno;
86		(void) unlink(pidfile_path);
87		free(pidfile_path);
88		pidfile_path = NULL;
89		errno = save_errno;
90		return (-1);
91	}
92
93	pidfile_pid = pid;
94	if (atexit(pidfile_cleanup) < 0) {
95		save_errno = errno;
96		(void) unlink(pidfile_path);
97		free(pidfile_path);
98		pidfile_path = NULL;
99		pidfile_pid = 0;
100		errno = save_errno;
101		return (-1);
102	}
103
104	return (0);
105}
106
107static void
108pidfile_cleanup(void)
109{
110
111	if (pidfile_path != NULL && pidfile_pid == getpid())
112		(void) unlink(pidfile_path);
113}
114