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 * Derived from FreeBSD head/lib/libutil/pidfile.c r231938
29 #include <sys/param.h>
46 char pf_path[MAXPATHLEN + 1];
51 static int _pidfile_remove(struct pidfh *pfh, int freeit);
54 pidfile_verify(const struct pidfh *pfh)
58 if (pfh == NULL || pfh->pf_fd == -1)
61 * Check remembered descriptor.
63 if (fstat(pfh->pf_fd, &sb) == -1)
65 if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
71 pidfile_read(const char *path, pid_t *pidptr)
73 char buf[16], *endptr;
76 fd = open(path, O_RDONLY);
80 i = read(fd, buf, sizeof(buf) - 1);
81 error = errno; /* Remember errno in case close() wants to change it. */
89 *pidptr = strtol(buf, &endptr, 10);
90 if (endptr != &buf[i])
97 pidfile_open(const char *path, mode_t mode, pid_t *pidptr)
101 int error, fd, len, count;
102 struct timespec rqtp;
110 pfh = malloc(sizeof(*pfh));
114 len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
116 if (len >= (int)sizeof(pfh->pf_path)) {
118 errno = ENAMETOOLONG;
123 * Open the PID file and obtain exclusive lock.
124 * We truncate PID file here only to remove old PID immediatelly,
125 * PID file will be truncated again in pidfile_write(), so
126 * pidfile_write() can be called multiple times.
128 fd = flopen(pfh->pf_path,
130 O_WRONLY | O_CREAT | O_TRUNC | O_NONBLOCK | O_CLOEXEC, mode);
132 O_WRONLY | O_CREAT | O_TRUNC | O_NONBLOCK, mode);
135 if (errno == EWOULDBLOCK && pidptr != NULL) {
138 rqtp.tv_nsec = 5000000;
140 errno = pidfile_read(pfh->pf_path, pidptr);
141 if (errno != EAGAIN || --count == 0)
147 if (errno == 0 || errno == EAGAIN)
155 if (fcntl(fd, F_SETFD, FD_CLOEXEC) == -1) {
157 unlink(pfh->pf_path);
166 * Remember file information, so in pidfile_write() we are sure we write
167 * to the proper descriptor.
169 if (fstat(fd, &sb) == -1) {
171 unlink(pfh->pf_path);
179 pfh->pf_dev = sb.st_dev;
180 pfh->pf_ino = sb.st_ino;
186 pidfile_write(struct pidfh *pfh)
192 * Check remembered descriptor, so we don't overwrite some other
193 * file if pidfile was closed and descriptor reused.
195 errno = pidfile_verify(pfh);
198 * Don't close descriptor, because we are not sure if it's ours.
205 * Truncate PID file, so multiple calls of pidfile_write() are allowed.
207 if (ftruncate(fd, 0) == -1) {
209 _pidfile_remove(pfh, 0);
214 snprintf(pidstr, sizeof(pidstr), "%u", getpid());
215 if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
217 _pidfile_remove(pfh, 0);
226 pidfile_close(struct pidfh *pfh)
230 error = pidfile_verify(pfh);
236 if (close(pfh->pf_fd) == -1)
247 _pidfile_remove(struct pidfh *pfh, int freeit)
251 error = pidfile_verify(pfh);
257 if (unlink(pfh->pf_path) == -1)
259 if (close(pfh->pf_fd) == -1) {
275 pidfile_remove(struct pidfh *pfh)
278 return (_pidfile_remove(pfh, 1));
283 pidfile_fileno(const struct pidfh *pfh)
286 if (pfh == NULL || pfh->pf_fd == -1) {