2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
33 #include <sys/capsicum.h>
51 char pf_dir[MAXPATHLEN + 1];
52 char pf_filename[MAXPATHLEN + 1];
57 static int _pidfile_remove(struct pidfh *pfh, int freeit);
60 pidfile_verify(const struct pidfh *pfh)
64 if (pfh == NULL || pfh->pf_fd == -1)
67 * Check remembered descriptor.
69 if (fstat(pfh->pf_fd, &sb) == -1)
71 if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
77 pidfile_read(int dirfd, const char *filename, pid_t *pidptr)
79 char buf[16], *endptr;
82 fd = openat(dirfd, filename, O_RDONLY | O_CLOEXEC);
86 i = read(fd, buf, sizeof(buf) - 1);
87 error = errno; /* Remember errno in case close() wants to change it. */
95 *pidptr = strtol(buf, &endptr, 10);
96 if (endptr != &buf[i])
103 pidfile_open(const char *pathp, mode_t mode, pid_t *pidptr)
105 char path[MAXPATHLEN];
108 int error, fd, dirfd, dirlen, filenamelen, count;
109 struct timespec rqtp;
110 cap_rights_t caprights;
112 pfh = malloc(sizeof(*pfh));
117 dirlen = snprintf(pfh->pf_dir, sizeof(pfh->pf_dir),
119 filenamelen = snprintf(pfh->pf_filename,
120 sizeof(pfh->pf_filename), "%s.pid", getprogname());
122 if (strlcpy(path, pathp, sizeof(path)) >= sizeof(path)) {
124 errno = ENAMETOOLONG;
127 dirlen = strlcpy(pfh->pf_dir, dirname(path),
128 sizeof(pfh->pf_dir));
129 (void)strlcpy(path, pathp, sizeof(path));
130 filenamelen = strlcpy(pfh->pf_filename, basename(path),
131 sizeof(pfh->pf_filename));
134 if (dirlen >= (int)sizeof(pfh->pf_dir) ||
135 filenamelen >= (int)sizeof(pfh->pf_filename)) {
137 errno = ENAMETOOLONG;
141 dirfd = open(pfh->pf_dir, O_CLOEXEC | O_DIRECTORY | O_NONBLOCK);
150 * Open the PID file and obtain exclusive lock.
151 * We truncate PID file here only to remove old PID immediately,
152 * PID file will be truncated again in pidfile_write(), so
153 * pidfile_write() can be called multiple times.
155 fd = flopenat(dirfd, pfh->pf_filename,
156 O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NONBLOCK, mode);
158 if (errno == EWOULDBLOCK) {
159 if (pidptr == NULL) {
164 rqtp.tv_nsec = 5000000;
166 errno = pidfile_read(dirfd,
167 pfh->pf_filename, pidptr);
168 if (errno != EAGAIN || --count == 0)
174 if (errno == 0 || errno == EAGAIN)
186 * Remember file information, so in pidfile_write() we are sure we write
187 * to the proper descriptor.
189 if (fstat(fd, &sb) == -1) {
193 if (cap_rights_limit(dirfd,
194 cap_rights_init(&caprights, CAP_UNLINKAT)) < 0 && errno != ENOSYS) {
198 if (cap_rights_limit(fd, cap_rights_init(&caprights, CAP_PWRITE,
199 CAP_FSTAT, CAP_FTRUNCATE, CAP_EVENT)) < 0 &&
204 pfh->pf_dirfd = dirfd;
206 pfh->pf_dev = sb.st_dev;
207 pfh->pf_ino = sb.st_ino;
213 unlinkat(dirfd, pfh->pf_filename, 0);
222 pidfile_write(struct pidfh *pfh)
228 * Check remembered descriptor, so we don't overwrite some other
229 * file if pidfile was closed and descriptor reused.
231 errno = pidfile_verify(pfh);
234 * Don't close descriptor, because we are not sure if it's ours.
241 * Truncate PID file, so multiple calls of pidfile_write() are allowed.
243 if (ftruncate(fd, 0) == -1) {
245 _pidfile_remove(pfh, 0);
250 snprintf(pidstr, sizeof(pidstr), "%u", getpid());
251 if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
253 _pidfile_remove(pfh, 0);
262 pidfile_close(struct pidfh *pfh)
266 error = pidfile_verify(pfh);
272 if (close(pfh->pf_fd) == -1)
274 if (close(pfh->pf_dirfd) == -1 && error == 0)
286 _pidfile_remove(struct pidfh *pfh, int freeit)
290 error = pidfile_verify(pfh);
296 if (funlinkat(pfh->pf_dirfd, pfh->pf_filename, pfh->pf_fd, 0) == -1) {
297 if (errno == EDEADLK)
301 if (close(pfh->pf_fd) == -1 && error == 0)
303 if (close(pfh->pf_dirfd) == -1 && error == 0)
317 pidfile_remove(struct pidfh *pfh)
320 return (_pidfile_remove(pfh, 1));
324 pidfile_fileno(const struct pidfh *pfh)
327 if (pfh == NULL || pfh->pf_fd == -1) {