CHROMIUM: build tools: Allow parallel use of cros_image_to_target.py

This change addresses a defect which prevents simultaneous use of
'cros_image_to_target.py'.

The issue is that the default invocation will always use the same port
number of HTTP communication.  This change, with default parameters,
will now start at the same port number, but will now instead iterate
through a number of ports (the number of ports is set to 10).

If no available port can be found, the script will fail with an
appropriate message.

If the user specifies a specific port, then only that port number will
be used; if the port is not available, the script will fail with an
approrpriate message.

BUG=chromium-os:17558
TEST=Uploaded two images simultaneously to different boards.

Change-Id: Icbbea12468fd766897daeecb0b7f1d3929f52a1c
Signed-off-by: Taylor Hutt <thutt@chromium.org>
Reviewed-on: http://gerrit.chromium.org/gerrit/4110
Reviewed-by: Paul Stewart <pstew@chromium.org>
Reviewed-by: Terry Lambert <tlambert@chromium.org>

bin/cros_image_to_target.py

@@ -1,6 +1,6 @@
 #!/usr/bin/python
 #
-# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Copyright (c) 2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -267,7 +267,7 @@ class CrosEnv(object):
       return None
     return self.ParseShVars(lsb_release)
 
-  def CreateServer(self, port, update_file, stateful_file):
+  def CreateServer(self, ports, update_file, stateful_file):
     """Start the devserver clone."""
 
     PingUpdateResponse.Setup(self.GetHash(update_file),
@@ -283,8 +283,15 @@ class CrosEnv(object):
                            FileUpdateResponse(stateful_file,
                                               verbose=self.verbose,
                                               have_pv=self.have_pv))
-
+    for port in ports:
-    self.http_server = BaseHTTPServer.HTTPServer(('', port), UpdateHandler)
+      try:
+        self.http_server = BaseHTTPServer.HTTPServer(('', port),
+                                                     UpdateHandler)
+        return port
+      except :
+        # NOP.  Select next port.
+        continue
+      return None
 
   def StartServer(self):
     self.Info('Starting http server')
@@ -564,6 +571,14 @@ class ChildFinished(Exception):
           self.status = 255
         raise self
 
+def MakePortList(user_supplied_port):
+  range_start = 8081
+  port_list = []
+  if user_supplied_port is not None:
+    range_length = 1
+  else:
+    range_length = 10
+  return range(range_start, range_start + range_length, 1)
 
 def main(argv):
   usage = 'usage: %prog [options]'
@@ -577,7 +592,7 @@ def main(argv):
                     help='Source image to install')
   parser.add_option('--image-name', dest='image_name',
                     help='Filename within image directory to load')
-  parser.add_option('--port', dest='port', default=8081, type='int',
+  parser.add_option('--port', dest='port', type='int',
                     help='TCP port to serve from and tunnel through')
   parser.add_option('--remote', dest='remote', default=None,
                     help='Remote device-under-test IP address')
@@ -677,7 +692,10 @@ def main(argv):
       not cros_env.BuildStateful(image_file, image_directory, stateful_file)):
     cros_env.Fatal()
 
-  cros_env.CreateServer(options.port, update_file, stateful_file)
+  port = cros_env.CreateServer(MakePortList(options.port),
+                               update_file, stateful_file)
+  if port is None:
+    cros_env.Fatal('Unable to find a port for CreateServer.')
 
   exit_status = 1
   if options.server_only:
@@ -690,7 +708,7 @@ def main(argv):
     else:
       try:
         time.sleep(SERVER_STARTUP_WAIT)
-        if cros_env.StartClient(options.port):
+        if cros_env.StartClient(port):
           exit_status = 0
       except KeyboardInterrupt:
         cros_env.Error('Client Exiting on Control-C')