tuned: new option --pid, -P to write PID file

If used without argument as --pid or -P the tuned will write the PID file even
if running in foreground. The PID file is always written if running as daemon.

If used with argument as --pid FILE or -P FILE, the PID will be written to
FILE. This is also applicable for daemon.

Signed-off-by: Jaroslav Škarvada <jskarvad@redhat.com>

tuned.py

@@ -36,7 +36,8 @@ if __name__ == "__main__":
 	parser = argparse.ArgumentParser(description = "Daemon for monitoring and adaptive tuning of system devices.")
 	parser.add_argument("--daemon", "-d", action = "store_true", help = "run on background")
 	parser.add_argument("--debug", "-D", action = "store_true", help = "show/log debugging messages")
-	parser.add_argument("--log", "-l", nargs = "?", const = consts.LOG_FILENAME, help = "log to file, default file: " + consts.LOG_FILENAME)
+	parser.add_argument("--log", "-l", nargs = "?", const = consts.LOG_FILE, help = "log to file, default file: " + consts.LOG_FILE)
+	parser.add_argument("--pid", "-P", nargs = "?", const = consts.PID_FILE, help = "write PID file, default file: " + consts.PID_FILE)
 	parser.add_argument("--no-dbus", action = "store_true", help = "do not attach to DBus")
 	parser.add_argument("--profile", "-p", action = "store", type=str, metavar = "name", help = "tuning profile to be activated")
 	parser.add_argument('--version', "-v", action = "version", version = "%%(prog)s %s.%s.%s" % (ver.TUNED_VERSION_MAJOR, ver.TUNED_VERSION_MINOR, ver.TUNED_VERSION_PATCH))
@@ -53,7 +54,7 @@ if __name__ == "__main__":
 	try:
 		if args.daemon:
 			if args.log is None:
-				args.log = consts.LOG_FILENAME
+				args.log = consts.LOG_FILE
 			log.switch_to_file(args.log)
 		else:
 			if args.log is not None:
@@ -65,7 +66,12 @@ if __name__ == "__main__":
 			app.attach_to_dbus(consts.DBUS_BUS, consts.DBUS_OBJECT, consts.DBUS_INTERFACE)
 
 		if args.daemon:
-			app.daemonize()
+			if args.pid is None:
+				args.pid = consts.PID_FILE
+			app.daemonize(args.pid)
+		else:
+			if args.pid is not None:
+				app.write_pid_file(args.pid)
 		app.run()
 
 	except tuned.exceptions.TunedException as exception:

tuned/consts.py

@@ -9,6 +9,6 @@ LOAD_DIRECTORIES = ["/usr/lib/tuned", "/etc/tuned"]
 # number of backups
 LOG_FILE_COUNT = 2
 LOG_FILE_MAXBYTES = 100*1000
-LOG_FILENAME = "/var/log/tuned/tuned.log"
+LOG_FILE = "/var/log/tuned/tuned.log"
 PID_FILE = "/run/tuned/tuned.pid"
 SYSTEM_RELEASE_FILE = "/etc/system-release-cpe"

tuned/daemon/application.py

@@ -64,7 +64,7 @@ class Application(object):
 		some uninteresting data into the pipe.
 		"""
 		os.close(child_out_fd)
-		(read_ready, drop, drop) = select.select([parent_in_fd], [], [], DAEMONIZE_PARENT_TIMEOUT)
+		(read_ready, drop, drop) = select.select([parent_in_fd], [], [], consts.DAEMONIZE_PARENT_TIMEOUT)
 
 		if len(read_ready) != 1:
 			os.close(parent_in_fd)
@@ -79,8 +79,8 @@ class Application(object):
 		if response != ("%c" % True):
 			raise TunedException("Cannot daemonize, child process reports failure.")
 
-	def _write_pid_file(self):
-		self._pid_file = PID_FILE
+	def write_pid_file(self, pid_file = consts.PID_FILE):
+		self._pid_file = pid_file
 		self._delete_pid_file()
 		try:
 			dir_name = os.path.dirname(self._pid_file)
@@ -100,7 +100,7 @@ class Application(object):
 			except OSError as error:
 				log.warning("cannot remove existing PID file %s, %s" % (self._pid_file, str(error)))
 
-	def _daemonize_child(self, parent_in_fd, child_out_fd):
+	def _daemonize_child(self, pid_file, parent_in_fd, child_out_fd):
 		"""
 		Finishes daemonizing process, writes a PID file and signalizes to the parent
 		that the initialization is complete.
@@ -128,13 +128,13 @@ class Application(object):
 		os.dup2(so.fileno(), sys.stdout.fileno())
 		os.dup2(se.fileno(), sys.stderr.fileno())
 
-		self._write_pid_file()
+		self.write_pid_file(pid_file)
 
 		log.debug("successfully daemonized")
 		os.write(child_out_fd, "%c" % True)
 		os.close(child_out_fd)
 
-	def daemonize(self):
+	def daemonize(self, pid_file = consts.PID_FILE):
 		"""
 		Daemonizes the application. In case of failure, TunedException is raised
 		in the parent process. If the operation is successfull, the main process
@@ -153,7 +153,7 @@ class Application(object):
 				self._daemonize_parent(*parent_child_fds)
 				sys.exit(0)
 			else:
-				self._daemonize_child(*parent_child_fds)
+				self._daemonize_child(pid_file, *parent_child_fds)
 		except:
 			# pass exceptions only into parent process
 			if child_pid > 0:

tuned/logs.py

@@ -51,7 +51,7 @@ class TunedLogger(logging.getLoggerClass()):
 		self.remove_all_handlers()
 		self.addHandler(self._console_handler)
 
-	def switch_to_file(self, filename = consts.LOG_FILENAME):
+	def switch_to_file(self, filename = consts.LOG_FILE):
 		self._setup_file_handler(filename)
 		self.remove_all_handlers()
 		self.addHandler(self._file_handler)