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: src/lib/libutil/pidfile.c,v 1.9 2008/10/20 17:41:08 des Exp $
29 #include <sys/param.h>
45 static int _pidfile_remove(struct pidfh *pfh, int freeit);
48 pidfile_verify(struct pidfh *pfh)
52 if (pfh == NULL || pfh->pf_fd == -1)
55 * Check remembered descriptor.
57 if (fstat(pfh->pf_fd, &sb) == -1)
59 if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
65 pidfile_read(const char *path, pid_t *pidptr)
67 char buf[16], *endptr;
70 fd = open(path, O_RDONLY);
74 i = read(fd, buf, sizeof(buf) - 1);
75 error = errno; /* Remember errno in case close() wants to change it. */
83 *pidptr = strtol(buf, &endptr, 10);
84 if (endptr != &buf[i])
91 pidfile_open(const char *path, mode_t mode, pid_t *pidptr)
95 int error, fd, len, count;
98 pfh = malloc(sizeof(*pfh));
103 len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
104 "/var/run/%s.pid", getprogname());
106 len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
108 if (len >= (int)sizeof(pfh->pf_path)) {
110 errno = ENAMETOOLONG;
115 * Open the PID file and obtain exclusive lock.
116 * We truncate PID file here only to remove old PID immediatelly,
117 * PID file will be truncated again in pidfile_write(), so
118 * pidfile_write() can be called multiple times.
120 fd = flopen(pfh->pf_path,
121 O_WRONLY | O_CREAT | O_TRUNC | O_NONBLOCK, mode);
125 rqtp.tv_nsec = 5000000;
126 if (errno == EWOULDBLOCK && pidptr != NULL) {
128 errno = pidfile_read(pfh->pf_path, pidptr);
131 else if (errno == EAGAIN) {
142 * Remember file information, so in pidfile_write() we are sure we write
143 * to the proper descriptor.
145 if (fstat(fd, &sb) == -1) {
147 unlink(pfh->pf_path);
155 pfh->pf_dev = sb.st_dev;
156 pfh->pf_ino = sb.st_ino;
162 pidfile_write(struct pidfh *pfh)
168 * Check remembered descriptor, so we don't overwrite some other
169 * file if pidfile was closed and descriptor reused.
171 errno = pidfile_verify(pfh);
174 * Don't close descriptor, because we are not sure if it's ours.
181 * Truncate PID file, so multiple calls of pidfile_write() are allowed.
183 if (ftruncate(fd, 0) == -1) {
185 _pidfile_remove(pfh, 0);
190 snprintf(pidstr, sizeof(pidstr), "%u", getpid());
191 if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
193 _pidfile_remove(pfh, 0);
202 pidfile_close(struct pidfh *pfh)
206 error = pidfile_verify(pfh);
212 if (close(pfh->pf_fd) == -1)
223 _pidfile_remove(struct pidfh *pfh, int freeit)
227 error = pidfile_verify(pfh);
233 if (unlink(pfh->pf_path) == -1)
235 if (close(pfh->pf_fd) == -1) {
251 pidfile_remove(struct pidfh *pfh)
254 return (_pidfile_remove(pfh, 1));