monitor = true;
}
-/* If a pidfile has been configured and that pidfile already exists and is
- * locked by a running process, returns the pid of the running process.
- * Otherwise, returns 0. */
-static pid_t
-already_running(void)
-{
- pid_t pid = 0;
- if (pidfile) {
- int fd = open(pidfile, O_RDWR);
- if (fd >= 0) {
- struct flock lck;
- lck.l_type = F_WRLCK;
- lck.l_whence = SEEK_SET;
- lck.l_start = 0;
- lck.l_len = 0;
- if (fcntl(fd, F_GETLK, &lck) != -1 && lck.l_type != F_UNLCK) {
- pid = lck.l_pid;
- }
- close(fd);
- }
- }
- return pid;
-}
-
/* If a locked pidfile exists, issue a warning message and, unless
* ignore_existing_pidfile() has been called, terminate the program. */
void
die_if_already_running(void)
{
- pid_t pid = already_running();
- if (pid) {
+ pid_t pid;
+ if (!pidfile) {
+ return;
+ }
+ pid = read_pidfile_if_exists(pidfile);
+ if (pid > 0) {
if (!overwrite_pidfile) {
VLOG_ERR("%s: %s already running as pid %ld, aborting",
get_pidfile(), program_name, (long int) pid);
ovs_rundir(), program_name);
}
-/* Opens and reads a PID from 'pidfile'. Returns the nonnegative PID if
- * successful, otherwise a negative errno value. */
-pid_t
-read_pidfile(const char *pidfile)
+static pid_t
+read_pidfile__(const char *pidfile, bool must_exist)
{
char line[128];
struct flock lck;
file = fopen(pidfile, "r");
if (!file) {
+ if (errno == ENOENT && !must_exist) {
+ return 0;
+ }
error = errno;
VLOG_WARN("%s: open: %s", pidfile, strerror(error));
goto error;
}
return -error;
}
+
+/* Opens and reads a PID from 'pidfile'. Returns the positive PID if
+ * successful, otherwise a negative errno value. */
+pid_t
+read_pidfile(const char *pidfile)
+{
+ return read_pidfile__(pidfile, true);
+}
+
+
+/* Opens and reads a PID from 'pidfile', if it exists. Returns 0 if 'pidfile'
+ * doesn't exist, the positive PID if successful, otherwise a negative errno
+ * value. */
+pid_t
+read_pidfile_if_exists(const char *pidfile)
+{
+ return read_pidfile__(pidfile, false);
+}