Make IsHostPortUsed() handle ports bound by foreign UIDs.

build/android/pylib/ports.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Functions that deal with local and device ports."""
 
 import contextlib
 import fcntl
 import httplib
 import logging
 import os
-import re
 import socket
 import traceback
 
 import cmd_helper
 import constants
 
 
 # The following two methods are used to allocate the port source for various
 # types of test servers. Because some net-related tests can be run on shards at
 # same time, it's important to have a mechanism to allocate the port
@@ skipping 53 matching lines @@
     logging.info('Allocate port %d for test server.', port)
   else:
     logging.error('Could not allocate port for test server. '
                   'List of ports tried: %s', str(ports_tried))
   return port
 
 
 def IsHostPortUsed(host_port):
   """Checks whether the specified host port is used or not.
 
-  Uses -n -P to inhibit the conversion of host/port numbers to host/port names.
-
   Args:
     host_port: Port on host we want to check.
 
   Returns:
     True if the port on host is already used, otherwise returns False.
   """
-  port_info = '(\*)|(127\.0\.0\.1)|(localhost):%d' % host_port
-  # TODO(jnd): Find a better way to filter the port. Note that connecting to the
-  # socket and closing it would leave it in the TIME_WAIT state. Setting
-  # SO_LINGER on it and then closing it makes the Python HTTP server crash.
-  re_port = re.compile(port_info, re.MULTILINE)
-  if re_port.search(cmd_helper.GetCmdOutput(['lsof', '-nPi:%d' % host_port])):
+  try:
+    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    sock.connect(('127.0.0.1', host_port))
     return True
-  return False
+  except socket.error as error:
+    return False
+  finally:
+    sock.close()
 
 
 def IsDevicePortUsed(adb, device_port, state=''):
   """Checks whether the specified device port is used or not.
 
   Args:
     adb: Instance of AndroidCommands for talking to the device.
     device_port: Port on device we want to check.
     state: String of the specified state. Default is empty string, which
            means any state.
@@ skipping 55 matching lines @@
         client_error = ('Bad response: %s %s version %s\n  ' %
                         (r.status, r.reason, r.version) +
                         '\n  '.join([': '.join(h) for h in r.getheaders()]))
     except (httplib.HTTPException, socket.error) as e:
       # Probably too quick connecting: try again.
       exception_error_msgs = traceback.format_exception_only(type(e), e)
       if exception_error_msgs:
         client_error = ''.join(exception_error_msgs)
   # Only returns last client_error.
   return (False, client_error or 'Timeout')