Make host port availability detection more robust.

Previously, it only detected ports that were bound to *, localhost or
127.0.0.1. This detects ports bound to any interface. I noticed this
while investigating 294878, and it could certainly be a source of
flake, but I don't think it's the main one.

BUG=294878

Review URL: https://codereview.chromium.org/634803002

Cr-Original-Commit-Position: refs/heads/master@{#299379}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: da7e64810f0305512cd20f0301c2ac1b21d8bc70

android/pylib/chrome_test_server_spawner.py

@@ -64,17 +64,14 @@ def _WaitUntil(predicate, max_attempts=5):
   return False
 
 
-def _CheckPortStatus(port, expected_status):
-  """Returns True if port has expected_status.
+def _CheckPortAvailable(port):
+  """Returns True if |port| is available."""
+  return _WaitUntil(lambda: ports.IsHostPortAvailable(port))
 
-  Args:
-    port: the port number.
-    expected_status: boolean of expected status.
 
-  Returns:
-    Returns True if the status is expected. Otherwise returns False.
-  """
-  return _WaitUntil(lambda: ports.IsHostPortUsed(port) == expected_status)
+def _CheckPortNotAvailable(port):
+  """Returns True if |port| is not available."""
+  return _WaitUntil(lambda: not ports.IsHostPortAvailable(port))
 
 
 def _CheckDevicePortStatus(device, port):
@@ -167,7 +164,7 @@ class TestServerThread(threading.Thread):
     port_json = json.loads(port_json)
     if port_json.has_key('port') and isinstance(port_json['port'], int):
       self.host_port = port_json['port']
-      return _CheckPortStatus(self.host_port, True)
+      return _CheckPortNotAvailable(self.host_port)
     logging.error('Failed to get port information from the server data.')
     return False
 
@@ -236,7 +233,7 @@ class TestServerThread(threading.Thread):
       if self.pipe_out:
         self.is_ready = self._WaitToStartAndGetPortFromTestServer()
       else:
-        self.is_ready = _CheckPortStatus(self.host_port, True)
+        self.is_ready = _CheckPortNotAvailable(self.host_port)
     if self.is_ready:
       Forwarder.Map([(0, self.host_port)], self.device, self.tool)
       # Check whether the forwarder is ready on the device.
@@ -346,7 +343,7 @@ class SpawningServerRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):
     logging.info('Handling request to kill a test server on port: %d.', port)
     self.server.test_server_instance.Stop()
     # Make sure the status of test server is correct before sending response.
-    if _CheckPortStatus(port, False):
+    if _CheckPortAvailable(port):
       self._SendResponse(200, 'OK', {}, 'killed')
       logging.info('Test server on port %d is killed', port)
     else:

android/pylib/ports.py

@@ -9,11 +9,9 @@ import fcntl
 import httplib
 import logging
 import os
-import re
 import socket
 import traceback
 
-from pylib import cmd_helper
 from pylib import constants
 
 
@@ -57,7 +55,7 @@ def AllocateTestServerPort():
     with open(constants.TEST_SERVER_PORT_FILE, 'r+') as fp:
       port = int(fp.read())
       ports_tried.append(port)
-      while IsHostPortUsed(port):
+      while not IsHostPortAvailable(port):
         port += 1
         ports_tried.append(port)
       if (port > constants.TEST_SERVER_PORT_LAST or
@@ -67,7 +65,7 @@ def AllocateTestServerPort():
         fp.seek(0, os.SEEK_SET)
         fp.write('%d' % (port + 1))
   except Exception as e:
-    logging.info(e)
+    logging.error(e)
   finally:
     if fp_lock:
       fcntl.flock(fp_lock, fcntl.LOCK_UN)
@@ -80,25 +78,23 @@ def AllocateTestServerPort():
   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.
+def IsHostPortAvailable(host_port):
+  """Checks whether the specified host port is available.
 
   Args:
-    host_port: Port on host we want to check.
+    host_port: Port on host to check.
 
   Returns:
-    True if the port on host is already used, otherwise returns False.
+    True if the port on host is available, 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])):
+  s = socket.socket()
+  try:
+    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+    s.bind(('', host_port))
+    s.close()
     return True
-  return False
+  except socket.error:
+    return False
 
 
 def IsDevicePortUsed(device, device_port, state=''):