pidfile.c revision 1.11 
1/*	$OpenBSD: pidfile.c,v 1.11 2015/06/03 02:24:36 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/types.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	if (asprintf(&pidfile_path, "%s%s.pid", _PATH_VARRUN, basename) == -1)
65		return (-1);
66
67	if ((f = fopen(pidfile_path, "w")) == NULL) {
68		save_errno = errno;
69		free(pidfile_path);
70		pidfile_path = NULL;
71		errno = save_errno;
72		return (-1);
73	}
74
75	pid = getpid();
76	if (fprintf(f, "%ld\n", (long)pid) <= 0 || fflush(f) != 0) {
77		save_errno = errno;
78		(void) fclose(f);
79		(void) unlink(pidfile_path);
80		free(pidfile_path);
81		pidfile_path = NULL;
82		errno = save_errno;
83		return (-1);
84	}
85	(void) fclose(f);
86
87	pidfile_pid = pid;
88	if (atexit(pidfile_cleanup) < 0) {
89		save_errno = errno;
90		(void) unlink(pidfile_path);
91		free(pidfile_path);
92		pidfile_path = NULL;
93		pidfile_pid = 0;
94		errno = save_errno;
95		return (-1);
96	}
97
98	return (0);
99}
100
101static void
102pidfile_cleanup(void)
103{
104
105	if (pidfile_path != NULL && pidfile_pid == getpid())
106		(void) unlink(pidfile_path);
107}
108