When xfrout is launched, check whether the socket file is being used by one...

When xfrout is launched, check whether the socket file is being used by one running xfrout process, if it is, exit from python. If the file isn't a socket file or nobody is listening, it will be removed. If it can't be removed, exit from python.

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@2091 e5f2f494-b856-4b98-b285-d166d9295462

ChangeLog

+  52.   [func]      zhanglikun
+	bin/xfrout: When xfrout is launched, check whether the
+	socket file is being used by one running xfrout process, 
+	if it is, exit from python.	If the file isn't a socket file 
+	or nobody is listening, it will be removed. If it can't 
+	be removed, exit from python.
+	(Trac #151, svn r2084)
+
 bind10-devel-20100602 released on June 2, 2010
 
   51.   [build]         jelte

src/bin/xfrout/tests/xfrout_test.py

@@ -278,6 +278,70 @@ class TestUnixSockServer(unittest.TestCase):
         self.unix.decrease_transfers_counter()
         self.assertEqual(count - 1, self.unix._transfers_counter)
 
+    def _remove_file(self, sock_file):
+        try:
+            os.remove(sock_file)
+        except OSError:
+            pass
+ 
+    def test_sock_file_in_use_file_exist(self):
+        sock_file = 'temp.sock.file'
+        self._remove_file(sock_file)
+        self.assertFalse(self.unix._sock_file_in_use(sock_file))
+        self.assertFalse(os.path.exists(sock_file))
+
+    def test_sock_file_in_use_file_not_exist(self):
+        self.assertFalse(self.unix._sock_file_in_use('temp.sock.file'))
+
+    def _start_unix_sock_server(self, sock_file):
+        serv = ThreadingUnixStreamServer(sock_file, BaseRequestHandler)
+        serv_thread = threading.Thread(target=serv.serve_forever)
+        serv_thread.setDaemon(True)
+        serv_thread.start()
+
+    def test_sock_file_in_use(self):
+        sock_file = 'temp.sock.file'
+        self._remove_file(sock_file)
+        self.assertFalse(self.unix._sock_file_in_use(sock_file))
+        self._start_unix_sock_server(sock_file)
+
+        old_stdout = sys.stdout
+        sys.stdout = open(os.devnull, 'w')
+        self.assertTrue(self.unix._sock_file_in_use(sock_file))
+        sys.stdout = old_stdout
+
+    def test_remove_unused_sock_file_in_use(self):
+        sock_file = 'temp.sock.file'
+        self._remove_file(sock_file)
+        self.assertFalse(self.unix._sock_file_in_use(sock_file))
+        self._start_unix_sock_server(sock_file)
+        old_stdout = sys.stdout
+        sys.stdout = open(os.devnull, 'w')
+        try:
+            self.unix._remove_unused_sock_file(sock_file)
+        except SystemExit:
+            pass
+        else:
+            # This should never happen
+            self.assertTrue(False)
+
+        sys.stdout = old_stdout
+
+    def test_remove_unused_sock_file_dir(self):
+        import tempfile
+        dir_name = tempfile.mkdtemp()
+        old_stdout = sys.stdout
+        sys.stdout = open(os.devnull, 'w')
+        try:
+            self.unix._remove_unused_sock_file(dir_name)
+        except SystemExit:
+            pass
+        else:
+            # This should never happen
+            self.assertTrue(False)
+
+        sys.stdout = old_stdout
+        os.rmdir(dir_name)
 
 if __name__== "__main__":
     unittest.main()

src/bin/xfrout/xfrout.py.in

@@ -28,6 +28,7 @@ import os
 from isc.config.ccsession import *
 from isc.cc import SessionError
 import socket
+import errno
 from optparse import OptionParser, OptionValueError
 try:
     from bind10_xfr import *
@@ -57,7 +58,13 @@ class XfroutSession(BaseRequestHandler):
     def handle(self):
         fd = recv_fd(self.request.fileno())
         if fd < 0:
-            raise XfroutException("failed to receive the FD for XFR connection")
+            # This may happen when one xfrout process try to connect to
+            # xfrout unix socket server, to check whether there is another
+            # xfrout running. 
+            print("[b10-xfrout] Failed to receive the FD for XFR connection, "
+                  "maybe because another xfrout process was started.")
+            return
+
         data_len = self.request.recv(2)
         msg_len = struct.unpack('!H', data_len)[0]
         msgdata = self.request.recv(msg_len)
@@ -277,18 +284,44 @@ class UnixSockServer(ThreadingUnixStreamServer):
     '''The unix domain socket server which accept xfr query sent from auth server.'''
 
     def __init__(self, sock_file, handle_class, shutdown_event, config_data):
-        try:
-            os.unlink(sock_file)
-        except:
-            pass
- 
+        self._remove_unused_sock_file(sock_file)
         self._sock_file = sock_file
         ThreadingUnixStreamServer.__init__(self, sock_file, handle_class)
         self._lock = threading.Lock()
         self._transfers_counter = 0
         self._shutdown_event = shutdown_event
         self.update_config_data(config_data)
-    
+
+    def _remove_unused_sock_file(self, sock_file):
+        '''Try to remove the socket file. If the file is being used 
+        by one running xfrout process, exit from python. 
+        If it's not a socket file or nobody is listening
+        , it will be removed. If it can't be removed, exit from python. '''
+        if self._sock_file_in_use(sock_file):
+            print("[b10-xfrout] Fail to start xfrout process, unix socket" 
+                  " file '%s' is being used by another xfrout process" % sock_file)
+            sys.exit(0)
+        else:
+            if not os.path.exists(sock_file):
+                return
+
+            try:
+                os.unlink(sock_file)
+            except OSError as err:
+                print('[b10-xfrout] Fail to remove file ' + sock_file, err)
+                sys.exit(0)
+   
+    def _sock_file_in_use(self, sock_file):
+        '''Check whether the socket file 'sock_file' exists and 
+        is being used by one running xfrout process. If it is, 
+        return True, or else return False. '''
+        try:
+            sock = socket.socket(socket.AF_UNIX)
+            sock.connect(sock_file)
+        except socket.error as err:
+            return False
+        else:
+            return True 
 
     def shutdown(self):
         ThreadingUnixStreamServer.shutdown(self)