2 * SPDX-License-Identifier: BSD-2-Clause
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/param.h>
30 #include <sys/types.h>
31 #include <sys/capsicum.h>
50 char pf_dir[MAXPATHLEN + 1];
51 char pf_filename[MAXPATHLEN + 1];
56 static int _pidfile_remove(struct pidfh *pfh, int freeit);
59 pidfile_verify(const struct pidfh *pfh)
63 if (pfh == NULL || pfh->pf_fd == -1)
66 * Check remembered descriptor.
68 if (fstat(pfh->pf_fd, &sb) == -1)
70 if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
76 pidfile_read_impl(int dirfd, const char *filename, pid_t *pidptr)
78 char buf[16], *endptr;
81 fd = openat(dirfd, filename, O_RDONLY | O_CLOEXEC);
85 i = read(fd, buf, sizeof(buf) - 1);
86 error = errno; /* Remember errno in case close() wants to change it. */
94 *pidptr = strtol(buf, &endptr, 10);
95 if (endptr != &buf[i])
102 pidfile_read(int dirfd, const char *filename, pid_t *pidptr)
104 struct timespec rqtp;
109 rqtp.tv_nsec = 5000000;
111 errno = pidfile_read_impl(dirfd, filename, pidptr);
112 if (errno != EAGAIN || --count == 0)
122 pidfile_open(const char *pathp, mode_t mode, pid_t *pidptr)
124 char path[MAXPATHLEN];
127 int error, fd, dirfd, dirlen, filenamelen;
128 cap_rights_t caprights;
130 pfh = malloc(sizeof(*pfh));
135 dirlen = snprintf(pfh->pf_dir, sizeof(pfh->pf_dir),
137 filenamelen = snprintf(pfh->pf_filename,
138 sizeof(pfh->pf_filename), "%s.pid", getprogname());
140 if (strlcpy(path, pathp, sizeof(path)) >= sizeof(path)) {
142 errno = ENAMETOOLONG;
145 dirlen = strlcpy(pfh->pf_dir, dirname(path),
146 sizeof(pfh->pf_dir));
147 (void)strlcpy(path, pathp, sizeof(path));
148 filenamelen = strlcpy(pfh->pf_filename, basename(path),
149 sizeof(pfh->pf_filename));
152 if (dirlen >= (int)sizeof(pfh->pf_dir) ||
153 filenamelen >= (int)sizeof(pfh->pf_filename)) {
155 errno = ENAMETOOLONG;
159 dirfd = open(pfh->pf_dir, O_CLOEXEC | O_DIRECTORY | O_NONBLOCK);
168 * Open the PID file and obtain exclusive lock.
169 * We truncate PID file here only to remove old PID immediately,
170 * PID file will be truncated again in pidfile_write(), so
171 * pidfile_write() can be called multiple times.
173 fd = flopenat(dirfd, pfh->pf_filename,
174 O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC | O_NONBLOCK, mode);
176 if (errno == EWOULDBLOCK) {
177 if (pidptr == NULL) {
180 errno = pidfile_read(dirfd,
181 pfh->pf_filename, pidptr);
182 if (errno == 0 || errno == EAGAIN)
194 * Remember file information, so in pidfile_write() we are sure we write
195 * to the proper descriptor.
197 if (fstat(fd, &sb) == -1) {
201 if (cap_rights_limit(dirfd,
202 cap_rights_init(&caprights, CAP_UNLINKAT)) < 0 && errno != ENOSYS) {
206 if (cap_rights_limit(fd, cap_rights_init(&caprights, CAP_PWRITE,
207 CAP_FSTAT, CAP_FTRUNCATE, CAP_EVENT)) < 0 &&
212 pfh->pf_dirfd = dirfd;
214 pfh->pf_dev = sb.st_dev;
215 pfh->pf_ino = sb.st_ino;
221 unlinkat(dirfd, pfh->pf_filename, 0);
230 pidfile_write(struct pidfh *pfh)
236 * Check remembered descriptor, so we don't overwrite some other
237 * file if pidfile was closed and descriptor reused.
239 errno = pidfile_verify(pfh);
242 * Don't close descriptor, because we are not sure if it's ours.
249 * Truncate PID file, so multiple calls of pidfile_write() are allowed.
251 if (ftruncate(fd, 0) == -1) {
253 _pidfile_remove(pfh, 0);
258 snprintf(pidstr, sizeof(pidstr), "%u", getpid());
259 if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
261 _pidfile_remove(pfh, 0);
270 pidfile_close(struct pidfh *pfh)
274 error = pidfile_verify(pfh);
280 if (close(pfh->pf_fd) == -1)
282 if (close(pfh->pf_dirfd) == -1 && error == 0)
294 _pidfile_remove(struct pidfh *pfh, int freeit)
298 error = pidfile_verify(pfh);
304 if (funlinkat(pfh->pf_dirfd, pfh->pf_filename, pfh->pf_fd, 0) == -1) {
305 if (errno == EDEADLK)
309 if (close(pfh->pf_fd) == -1 && error == 0)
311 if (close(pfh->pf_dirfd) == -1 && error == 0)
325 pidfile_remove(struct pidfh *pfh)
328 return (_pidfile_remove(pfh, 1));
332 pidfile_fileno(const struct pidfh *pfh)
335 if (pfh == NULL || pfh->pf_fd == -1) {
343 pidfile_signal(const char *pathp, int sig, pid_t *pidptr)
348 fd = flopenat(AT_FDCWD, pathp,
349 O_RDONLY | O_CLOEXEC | O_NONBLOCK);
352 * The file exists but is not locked,
353 * so the daemon is dead. Nothing to do.
359 if (errno != EWOULDBLOCK) {
362 errno = pidfile_read(AT_FDCWD, pathp, &pid);
366 * Refuse to send broadcast or group signals, this has
367 * happened due to the bugs in pidfile(3).