2 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
43 static int _pidfile_remove(struct pidfh *pfh, int freeit);
46 pidfile_verify(struct pidfh *pfh)
51 if (pfh == NULL || pfh->pf_fd == -1)
54 * Check remembered descriptor.
56 if (fstat(pfh->pf_fd, &sb) == -1)
58 if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
64 pidfile_read(const char *path, pid_t *pidptr)
66 char buf[16], *endptr;
69 fd = open(path, O_RDONLY);
73 i = read(fd, buf, sizeof(buf) - 1);
74 error = errno; /* Remember errno in case close() wants to change it. */
80 *pidptr = strtol(buf, &endptr, 10);
81 if (endptr != &buf[i])
88 pidfile_open(const char *path, mode_t mode, pid_t *pidptr)
94 pfh = malloc(sizeof(*pfh));
99 snprintf(pfh->pf_path, sizeof(pfh->pf_path), "/var/run/%s.pid",
102 strlcpy(pfh->pf_path, path, sizeof(pfh->pf_path));
104 if (strlen(pfh->pf_path) == sizeof(pfh->pf_path) - 1) {
106 errno = ENAMETOOLONG;
111 * Open the PID file and obtain exclusive lock.
112 * We truncate PID file here only to remove old PID immediatelly,
113 * PID file will be truncated again in pidfile_write(), so
114 * pidfile_write() can be called multiple times.
116 fd = open(pfh->pf_path,
117 O_WRONLY | O_CREAT | O_EXLOCK | O_TRUNC | O_NONBLOCK, mode);
119 if (errno == EWOULDBLOCK && pidptr != NULL) {
120 errno = pidfile_read(pfh->pf_path, pidptr);
128 * Remember file information, so in pidfile_write() we are sure we write
129 * to the proper descriptor.
131 if (fstat(fd, &sb) == -1) {
133 unlink(pfh->pf_path);
141 pfh->pf_dev = sb.st_dev;
142 pfh->pf_ino = sb.st_ino;
148 pidfile_write(struct pidfh *pfh)
155 * Check remembered descriptor, so we don't overwrite some other
156 * file if pidfile was closed and descriptor reused.
158 errno = pidfile_verify(pfh);
161 * Don't close descriptor, because we are not sure if it's ours.
168 * Truncate PID file, so multiple calls of pidfile_write() are allowed.
170 if (ftruncate(fd, 0) == -1) {
172 _pidfile_remove(pfh, 0);
177 snprintf(pidstr, sizeof(pidstr), "%u", getpid());
178 if (write(fd, pidstr, strlen(pidstr)) != (ssize_t)strlen(pidstr)) {
180 _pidfile_remove(pfh, 0);
189 pidfile_close(struct pidfh *pfh)
193 error = pidfile_verify(pfh);
199 if (close(pfh->pf_fd) == -1)
210 _pidfile_remove(struct pidfh *pfh, int freeit)
214 error = pidfile_verify(pfh);
220 if (unlink(pfh->pf_path) == -1)
222 if (flock(pfh->pf_fd, LOCK_UN) == -1) {
226 if (close(pfh->pf_fd) == -1) {
242 pidfile_remove(struct pidfh *pfh)
245 return (_pidfile_remove(pfh, 1));