--- /dev/null
+/*-
+ * Copyright (c) 2005 Pawel Jakub Dawidek <pjd@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "pidfile.h"
+#include "flopen.h"
+
+#include <sys/cdefs.h>
+#include <sys/file.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <time.h>
+#include <err.h>
+#include <errno.h>
+
+static int _pidfile_remove(struct pidfh *pfh, int freeit);
+
+static int
+pidfile_verify(struct pidfh *pfh)
+{
+ struct stat sb;
+
+ if (pfh == NULL || pfh->pf_fd == -1)
+ return (EINVAL);
+ /*
+ * Check remembered descriptor.
+ */
+ if (fstat(pfh->pf_fd, &sb) == -1)
+ return (errno);
+ if (sb.st_dev != pfh->pf_dev || sb.st_ino != pfh->pf_ino)
+ return (EINVAL);
+ return (0);
+}
+
+static int
+pidfile_read(const char *path, pid_t *pidptr)
+{
+ char buf[16], *endptr;
+ int error, fd, i;
+
+ fd = open(path, O_RDONLY);
+ if (fd == -1)
+ return (errno);
+
+ i = read(fd, buf, sizeof(buf) - 1);
+ error = errno; /* Remember errno in case close() wants to change it. */
+ close(fd);
+ if (i == -1)
+ return (error);
+ else if (i == 0)
+ return (EAGAIN);
+ buf[i] = '\0';
+
+ *pidptr = strtol(buf, &endptr, 10);
+ if (endptr != &buf[i])
+ return (EINVAL);
+
+ return (0);
+}
+
+struct pidfh *
+pidfile_open(const char *path, mode_t mode, pid_t *pidptr)
+{
+ struct pidfh *pfh;
+ struct stat sb;
+ int error, fd, len, count;
+ struct timespec rqtp;
+
+ pfh = malloc(sizeof(*pfh));
+ if (pfh == NULL)
+ return (NULL);
+
+ if (path == NULL)
+ len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
+ "/var/run/%s.pid", getprogname());
+ else
+ len = snprintf(pfh->pf_path, sizeof(pfh->pf_path),
+ "%s", path);
+ if (len >= (int)sizeof(pfh->pf_path)) {
+ free(pfh);
+ errno = ENAMETOOLONG;
+ return (NULL);
+ }
+
+ /*
+ * Open the PID file and obtain exclusive lock.
+ * We truncate PID file here only to remove old PID immediatelly,
+ * PID file will be truncated again in pidfile_write(), so
+ * pidfile_write() can be called multiple times.
+ */
+ fd = flopen(pfh->pf_path,
+ O_WRONLY | O_CREAT | O_TRUNC | O_NONBLOCK, mode);
+ if (fd == -1) {
+ count = 0;
+ rqtp.tv_sec = 0;
+ rqtp.tv_nsec = 5000000;
+ if (errno == EWOULDBLOCK && pidptr != NULL) {
+ again:
+ errno = pidfile_read(pfh->pf_path, pidptr);
+ if (errno == 0)
+ errno = EEXIST;
+ else if (errno == EAGAIN) {
+ if (++count <= 3) {
+ nanosleep(&rqtp, 0);
+ goto again;
+ }
+ }
+ }
+ free(pfh);
+ return (NULL);
+ }
+ /*
+ * Remember file information, so in pidfile_write() we are sure we write
+ * to the proper descriptor.
+ */
+ if (fstat(fd, &sb) == -1) {
+ error = errno;
+ unlink(pfh->pf_path);
+ close(fd);
+ free(pfh);
+ errno = error;
+ return (NULL);
+ }
+
+ pfh->pf_fd = fd;
+ pfh->pf_dev = sb.st_dev;
+ pfh->pf_ino = sb.st_ino;
+
+ return (pfh);
+}
+
+int
+pidfile_write(struct pidfh *pfh)
+{
+ char pidstr[16];
+ int error, fd;
+
+ /*
+ * Check remembered descriptor, so we don't overwrite some other
+ * file if pidfile was closed and descriptor reused.
+ */
+ errno = pidfile_verify(pfh);
+ if (errno != 0) {
+ /*
+ * Don't close descriptor, because we are not sure if it's ours.
+ */
+ return (-1);
+ }
+ fd = pfh->pf_fd;
+
+ /*
+ * Truncate PID file, so multiple calls of pidfile_write() are allowed.
+ */
+ if (ftruncate(fd, 0) == -1) {
+ error = errno;
+ _pidfile_remove(pfh, 0);
+ errno = error;
+ return (-1);
+ }
+
+ snprintf(pidstr, sizeof(pidstr), "%u", getpid());
+ if (pwrite(fd, pidstr, strlen(pidstr), 0) != (ssize_t)strlen(pidstr)) {
+ error = errno;
+ _pidfile_remove(pfh, 0);
+ errno = error;
+ return (-1);
+ }
+
+ return (0);
+}
+
+int
+pidfile_close(struct pidfh *pfh)
+{
+ int error;
+
+ error = pidfile_verify(pfh);
+ if (error != 0) {
+ errno = error;
+ return (-1);
+ }
+
+ if (close(pfh->pf_fd) == -1)
+ error = errno;
+ free(pfh);
+ if (error != 0) {
+ errno = error;
+ return (-1);
+ }
+ return (0);
+}
+
+static int
+_pidfile_remove(struct pidfh *pfh, int freeit)
+{
+ int error;
+
+ error = pidfile_verify(pfh);
+ if (error != 0) {
+ errno = error;
+ return (-1);
+ }
+
+ if (unlink(pfh->pf_path) == -1)
+ error = errno;
+ if (flock(pfh->pf_fd, LOCK_UN) == -1) {
+ if (error == 0)
+ error = errno;
+ }
+ if (close(pfh->pf_fd) == -1) {
+ if (error == 0)
+ error = errno;
+ }
+ if (freeit)
+ free(pfh);
+ else
+ pfh->pf_fd = -1;
+ if (error != 0) {
+ errno = error;
+ return (-1);
+ }
+ return (0);
+}
+
+int
+pidfile_remove(struct pidfh *pfh)
+{
+
+ return (_pidfile_remove(pfh, 1));
+}
projects / daemon.git / blobdiff