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
26 * $FreeBSD: head/lib/libutil/pidfile.c 255007 2013-08-28 21:10:37Z jilles $
29 #include <sys/param.h>
44 char pf_path[MAXPATHLEN + 1];
49 static int _pidfile_remove(struct pidfh *pfh, int freeit);
52 pidfile_verify(const struct pidfh *pfh)
56 if (pfh == NULL || pfh->pf_fd == -1)
59 * Check remembered descriptor.
61 if (fstat(pfh->pf_fd, &sb) == -1)
63 if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
69 pidfile_read(const char *path, pid_t *pidptr)
71 char buf[16], *endptr;
74 fd = open(path, O_RDONLY | O_CLOEXEC);
78 i = read(fd, buf, sizeof(buf) - 1);
79 error = errno; /* Remember errno in case close() wants to change it. */
87 *pidptr = strtol(buf, &endptr, 10);
88 if (endptr != &buf[i])
95 pidfile_open(const char *path, mode_t mode, pid_t *pidptr)
99 int error, fd, len, count;
100 struct timespec rqtp;
102 pfh = malloc(sizeof(*pfh));
107 len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
108 "/var/run/%s.pid", getprogname());
110 len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
112 if (len >= (int)sizeof(pfh->pf_path)) {
114 errno = ENAMETOOLONG;
119 * Open the PID file and obtain exclusive lock.
120 * We truncate PID file here only to remove old PID immediatelly,
121 * PID file will be truncated again in pidfile_write(), so
122 * pidfile_write() can be called multiple times.
124 fd = flopen(pfh->pf_path,
125 O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NONBLOCK, mode);
127 if (errno == EWOULDBLOCK) {
128 if (pidptr == NULL) {
133 rqtp.tv_nsec = 5000000;
135 errno = pidfile_read(pfh->pf_path,
137 if (errno != EAGAIN || --count == 0)
143 if (errno == 0 || errno == EAGAIN)
152 * Remember file information, so in pidfile_write() we are sure we write
153 * to the proper descriptor.
155 if (fstat(fd, &sb) == -1) {
157 unlink(pfh->pf_path);
165 pfh->pf_dev = sb.st_dev;
166 pfh->pf_ino = sb.st_ino;
172 pidfile_write(struct pidfh *pfh)
178 * Check remembered descriptor, so we don't overwrite some other
179 * file if pidfile was closed and descriptor reused.
181 errno = pidfile_verify(pfh);
184 * Don't close descriptor, because we are not sure if it's ours.
191 * Truncate PID file, so multiple calls of pidfile_write() are allowed.
193 if (ftruncate(fd, 0) == -1) {
195 _pidfile_remove(pfh, 0);
200 snprintf(pidstr, sizeof(pidstr), "%u", getpid());
201 if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
203 _pidfile_remove(pfh, 0);
212 pidfile_close(struct pidfh *pfh)
216 error = pidfile_verify(pfh);
222 if (close(pfh->pf_fd) == -1)
233 _pidfile_remove(struct pidfh *pfh, int freeit)
237 error = pidfile_verify(pfh);
243 if (unlink(pfh->pf_path) == -1)
245 if (close(pfh->pf_fd) == -1) {
261 pidfile_remove(struct pidfh *pfh)
264 return (_pidfile_remove(pfh, 1));
268 pidfile_fileno(const struct pidfh *pfh)
271 if (pfh == NULL || pfh->pf_fd == -1) {