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 *path, mode_t mode, pid_t *pidptr)
107 int error, fd, dirfd, dirlen, filenamelen, count;
108 struct timespec rqtp;
109 cap_rights_t caprights;
111 pfh = malloc(sizeof(*pfh));
116 dirlen = snprintf(pfh->pf_dir, sizeof(pfh->pf_dir),
118 filenamelen = snprintf(pfh->pf_filename,
119 sizeof(pfh->pf_filename), "%s.pid", getprogname());
121 dirlen = snprintf(pfh->pf_dir, sizeof(pfh->pf_dir),
123 filenamelen = snprintf(pfh->pf_filename,
124 sizeof(pfh->pf_filename), "%s", path);
126 dirname(pfh->pf_dir);
127 basename(pfh->pf_filename);
130 if (dirlen >= (int)sizeof(pfh->pf_dir) ||
131 filenamelen >= (int)sizeof(pfh->pf_filename)) {
133 errno = ENAMETOOLONG;
137 dirfd = open(pfh->pf_dir, O_CLOEXEC | O_DIRECTORY | O_NONBLOCK);
146 * Open the PID file and obtain exclusive lock.
147 * We truncate PID file here only to remove old PID immediately,
148 * PID file will be truncated again in pidfile_write(), so
149 * pidfile_write() can be called multiple times.
151 fd = flopenat(dirfd, pfh->pf_filename,
152 O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NONBLOCK, mode);
154 if (errno == EWOULDBLOCK) {
155 if (pidptr == NULL) {
160 rqtp.tv_nsec = 5000000;
162 errno = pidfile_read(dirfd,
163 pfh->pf_filename, pidptr);
164 if (errno != EAGAIN || --count == 0)
170 if (errno == 0 || errno == EAGAIN)
182 * Remember file information, so in pidfile_write() we are sure we write
183 * to the proper descriptor.
185 if (fstat(fd, &sb) == -1) {
189 if (cap_rights_limit(dirfd,
190 cap_rights_init(&caprights, CAP_UNLINKAT)) < 0 && errno != ENOSYS) {
194 if (cap_rights_limit(fd, cap_rights_init(&caprights, CAP_PWRITE,
195 CAP_FSTAT, CAP_FTRUNCATE)) < 0 &&
200 pfh->pf_dirfd = dirfd;
202 pfh->pf_dev = sb.st_dev;
203 pfh->pf_ino = sb.st_ino;
209 unlinkat(dirfd, pfh->pf_filename, 0);
218 pidfile_write(struct pidfh *pfh)
224 * Check remembered descriptor, so we don't overwrite some other
225 * file if pidfile was closed and descriptor reused.
227 errno = pidfile_verify(pfh);
230 * Don't close descriptor, because we are not sure if it's ours.
237 * Truncate PID file, so multiple calls of pidfile_write() are allowed.
239 if (ftruncate(fd, 0) == -1) {
241 _pidfile_remove(pfh, 0);
246 snprintf(pidstr, sizeof(pidstr), "%u", getpid());
247 if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
249 _pidfile_remove(pfh, 0);
258 pidfile_close(struct pidfh *pfh)
262 error = pidfile_verify(pfh);
268 if (close(pfh->pf_fd) == -1)
270 if (close(pfh->pf_dirfd) == -1 && error == 0)
282 _pidfile_remove(struct pidfh *pfh, int freeit)
286 error = pidfile_verify(pfh);
292 if (unlinkat(pfh->pf_dirfd, pfh->pf_filename, 0) == -1)
294 if (close(pfh->pf_fd) == -1 && error == 0)
296 if (close(pfh->pf_dirfd) == -1 && error == 0)
310 pidfile_remove(struct pidfh *pfh)
313 return (_pidfile_remove(pfh, 1));
317 pidfile_fileno(const struct pidfh *pfh)
320 if (pfh == NULL || pfh->pf_fd == -1) {