pidfile.c revision 1.9 
1/*	$OpenBSD: pidfile.c,v 1.9 2013/10/01 16:47:42 millert 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 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33#include <sys/param.h>
34#include <errno.h>
35#include <paths.h>
36#include <stdio.h>
37#include <stdlib.h>
38#include <unistd.h>
39#include <util.h>
40
41static char *pidfile_path;
42static pid_t pidfile_pid;
43
44static void pidfile_cleanup(void);
45
46extern char *__progname;
47
48int
49pidfile(const char *basename)
50{
51	int save_errno;
52	pid_t pid;
53	FILE *f;
54
55	if (basename == NULL)
56		basename = __progname;
57
58	if (pidfile_path != NULL) {
59		free(pidfile_path);
60		pidfile_path = NULL;
61	}
62
63	/* _PATH_VARRUN includes trailing / */
64	(void) asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename);
65	if (pidfile_path == NULL)
66		return (-1);
67
68	if ((f = fopen(pidfile_path, "w")) == NULL) {
69		save_errno = errno;
70		free(pidfile_path);
71		pidfile_path = NULL;
72		errno = save_errno;
73		return (-1);
74	}
75
76	pid = getpid();
77	if (fprintf(f, "%ld\n", (long)pid) <= 0 || fflush(f) != 0) {
78		save_errno = errno;
79		(void) fclose(f);
80		(void) unlink(pidfile_path);
81		free(pidfile_path);
82		pidfile_path = NULL;
83		errno = save_errno;
84		return (-1);
85	}
86	(void) fclose(f);
87
88	pidfile_pid = pid;
89	if (atexit(pidfile_cleanup) < 0) {
90		save_errno = errno;
91		(void) unlink(pidfile_path);
92		free(pidfile_path);
93		pidfile_path = NULL;
94		pidfile_pid = 0;
95		errno = save_errno;
96		return (-1);
97	}
98
99	return (0);
100}
101
102static void
103pidfile_cleanup(void)
104{
105
106	if (pidfile_path != NULL && pidfile_pid == getpid())
107		(void) unlink(pidfile_path);
108}
109