pidfile.c revision 1.3 
1/*	$OpenBSD: pidfile.c,v 1.3 2002/01/02 10:22:18 mpech 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#if defined(LIBC_SCCS) && !defined(lint)
41static const char rcsid[] = "$OpenBSD: pidfile.c,v 1.3 2002/01/02 10:22:18 mpech Exp $";
42#endif /* LIBC_SCCS and not lint */
43
44#include <sys/param.h>
45#include <errno.h>
46#include <paths.h>
47#include <stdio.h>
48#include <stdlib.h>
49#include <unistd.h>
50#include <util.h>
51
52static char *pidfile_path;
53static pid_t pidfile_pid;
54
55static void pidfile_cleanup(void);
56
57extern char *__progname;
58
59int
60pidfile(const char *basename)
61{
62	FILE *f;
63	int save_errno;
64	pid_t pid;
65
66	if (basename == NULL)
67		basename = __progname;
68
69	if (pidfile_path != NULL) {
70		free(pidfile_path);
71		pidfile_path = NULL;
72	}
73
74	/* _PATH_VARRUN includes trailing / */
75	(void) asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename);
76	if (pidfile_path == NULL)
77		return (-1);
78
79	if ((f = fopen(pidfile_path, "w")) == NULL) {
80		save_errno = errno;
81		free(pidfile_path);
82		pidfile_path = NULL;
83		errno = save_errno;
84		return (-1);
85	}
86
87	pid = getpid();
88	if (fprintf(f, "%d\n", pid) <= 0 || fclose(f) != 0) {
89		save_errno = errno;
90		(void) unlink(pidfile_path);
91		free(pidfile_path);
92		pidfile_path = NULL;
93		errno = save_errno;
94		return (-1);
95	}
96
97	pidfile_pid = pid;
98	(void) atexit(pidfile_cleanup);
99
100	return (0);
101}
102
103static void
104pidfile_cleanup(void)
105{
106
107	if (pidfile_path != NULL && pidfile_pid == getpid())
108		(void) unlink(pidfile_path);
109}
110