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);
+}
global _monitor
_monitor = True
-def _already_running():
- """If a pidfile has been configured and that pidfile already exists and is
- locked by a running process, returns True. Otherwise, returns False."""
- if _pidfile is not None:
- try:
- file = open(_pidfile, "r+")
- try:
- try:
- fcntl.lockf(file, fcntl.LOCK_EX | fcntl.LOCK_NB)
- except IOError, e:
- if e.errno in [errno.EACCES, errno.EAGAIN]:
- return True
- logging.error("error locking %s (%s)"
- % (_pidfile, os.strerror(e.errno)))
- return False
- finally:
- # This releases the lock, which we don't really want.
- file.close()
- except IOError, e:
- if e.errno == errno.ENOENT:
- return False
- logging.error("error opening %s (%s)"
- % (_pidfile, os.strerror(e.errno)))
- return False
-
def die_if_already_running():
"""If a locked pidfile exists, issue a warning message and, unless
ignore_existing_pidfile() has been called, terminate the program."""
- if _already_running():
+ if _pidfile is None:
+ return
+ pid = read_pidfile_if_exists(_pidfile)
+ if pid > 0:
if not _overwrite_pidfile:
- msg = "%s: already running" % _pidfile
+ msg = "%s: already running as pid %d" % (_pidfile, pid)
logging.error("%s, aborting" % msg)
sys.stderr.write("%s\n" % msg)
sys.exit(1)
--overwrite-pidfile with --pidfile, start even if already running
""" % (ovs.dirs.RUNDIR, ovs.util.PROGRAM_NAME))
-def read_pidfile(pidfile):
- """Opens and reads a PID from 'pidfile'. Returns the nonnegative PID if
- successful, otherwise a negative errno value."""
+def __read_pidfile(pidfile, must_exist):
if _pidfile_dev is not None:
try:
s = os.stat(pidfile)
try:
file = open(pidfile, "r")
except IOError, e:
+ if e.errno == errno.ENOENT and not must_exist:
+ return 0
logging.warning("%s: open: %s" % (pidfile, os.strerror(e.errno)))
return -e.errno
except IOError:
pass
+def read_pidfile(pidfile):
+ """Opens and reads a PID from 'pidfile'. Returns the positive PID if
+ successful, otherwise a negative errno value."""
+ return __read_pidfile(pidfile, True)
+
+def read_pidfile_if_exists(pidfile):
+ """Opens and reads a PID from 'pidfile'. Returns 0 if 'pidfile' does not
+ exist, the positive PID if successful, otherwise a negative errno value."""
+ return __read_pidfile(pidfile, False)
+
# XXX Python's getopt does not support options with optional arguments, so we
# have to separate --pidfile (with no argument) from --pidfile-name (with an
# argument). Need to write our own getopt I guess.