RF: _rebindSignal helper to centralize assignment of new signal handlers + minor PEP8ing

fail2ban/server/server.py

@@ -87,6 +87,11 @@ class Server:
 		logSys.debug("Caught signal %d. Flushing logs" % signum)
 		self.flushLogs()
 
+	def _rebindSignal(self, s, new):
+		"""Bind new signal handler while storing old one in _prev_signals"""
+		self.__prev_signals[s] = signal.getsignal(s)
+		signal.signal(s, new)
+
 	def start(self, sock, pidfile, force=False, conf={}):
 		# First set the mask to only allow access to owner
 		os.umask(0077)
@@ -120,9 +125,10 @@ class Server:
 
 		# Install signal handlers
 		if _thread_name() == '_MainThread':
-			for s in (signal.SIGTERM, signal.SIGINT, signal.SIGUSR1):
+			for s in (signal.SIGTERM, signal.SIGINT):
-				self.__prev_signals[s] = signal.getsignal(s)
+				self._rebindSignal(s, self.__sigTERMhandler)
-				signal.signal(s, self.__sigTERMhandler if s != signal.SIGUSR1 else self.__sigUSR1handler)
+			self._rebindSignal(signal.SIGUSR1, self.__sigUSR1handler)
+
 		# Ensure unhandled exceptions are logged
 		sys.excepthook = excepthook
 
@@ -501,7 +507,7 @@ class Server:
 			hdlr.setFormatter(formatter)
 			logger.addHandler(hdlr)
 			# Does not display this message at startup.
-			if not self.__logTarget is None:
+			if self.__logTarget is not None:
 				logSys.info("Start Fail2ban v%s", version.version)
 				logSys.info(
 					"Changed logging target to %s for Fail2ban v%s"
@@ -588,9 +594,7 @@ class Server:
 		# We need to set this in the parent process, so it gets inherited by the
 		# child process, and this makes sure that it is effect even if the parent
 		# terminates quickly.
-		for s in (signal.SIGHUP,):
+		self._rebindSignal(signal.SIGHUP, signal.SIG_IGN)
-			self.__prev_signals[s] = signal.getsignal(s)
-			signal.signal(s, signal.SIG_IGN)
 
 		try:
 			# Fork a child process so the parent can exit.  This will return control