Remove XSESSION_COMMAND from Me2Me script

remoting/tools/me2me_virtual_host.py

 #!/usr/bin/python
 # 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.
 
 # Virtual Me2Me implementation.  This script runs and manages the processes
 # required for a Virtual Me2Me desktop, which are: X server, X desktop
 # session, and Host process.
 # This script is intended to run continuously as a background daemon
 # process, running under an ordinary (non-root) user account.
 
 import atexit
 import errno
 import getpass
 import hashlib
 import json
 import logging
 import optparse
 import os
 import signal
 import socket
 import subprocess
 import sys
 import tempfile
 import time
 import uuid
 
-# By default this script will try to determine the most appropriate X session
-# command for the system.  To use a specific session instead, set this variable
-# to the executable filename, or a list containing the executable and any
-# arguments, for example:
-# XSESSION_COMMAND = "/usr/bin/gnome-session-fallback"
-# XSESSION_COMMAND = ["/usr/bin/gnome-session", "--session=ubuntu-2d"]
-XSESSION_COMMAND = None
-
 LOG_FILE_ENV_VAR = "CHROME_REMOTE_DESKTOP_LOG_FILE"
 
 # This script has a sensible default for the initial and maximum desktop size,
 # which can be overridden either on the command-line, or via a comma-separated
 # list of sizes in this environment variable.
 DEFAULT_SIZES_ENV_VAR = "CHROME_REMOTE_DESKTOP_DEFAULT_DESKTOP_SIZES"
 
 # By default, provide a relatively small size to handle the case where resize-
 # to-client is disabled, and a much larger size to support clients with large
 # or mulitple monitors. These defaults can be overridden in ~/.profile.
@@ skipping 302 matching lines @@
 
     devnull.close()
 
   def _launch_x_session(self):
     # Start desktop session
     # The /dev/null input redirection is necessary to prevent the X session
     # reading from stdin.  If this code runs as a shell background job in a
     # terminal, any reading from stdin causes the job to be suspended.
     # Daemonization would solve this problem by separating the process from the
     # controlling terminal.
-    logging.info("Launching X session: %s" % XSESSION_COMMAND)
-    self.session_proc = subprocess.Popen(XSESSION_COMMAND,
+    xsession_command = choose_x_session()
+    if xsession_command is None:
+      raise Exception("Unable to choose suitable X session command.")
+
+    logging.info("Launching X session: %s" % xsession_command)
+    self.session_proc = subprocess.Popen(xsession_command,
                                          stdin=open(os.devnull, "r"),
                                          cwd=HOME_DIR,
                                          env=self.child_env)
     if not self.session_proc.pid:
       raise Exception("Could not start X session")
 
   def launch_session(self, x_args):
     self._init_child_env()
     self._setup_pulseaudio()
     self._launch_x_server(x_args)
@@ skipping 94 matching lines @@
 
     This is called on process termination.
     """
     if self.created:
       os.remove(self.filename)
 
 
 def choose_x_session():
   """Chooses the most appropriate X session command for this system.
 
-  If XSESSION_COMMAND is already set, its value is returned directly.
-  Otherwise, a session is chosen for this system.
-
   Returns:
     A string containing the command to run, or a list of strings containing
     the executable program and its arguments, which is suitable for passing as
     the first parameter of subprocess.Popen().  If a suitable session cannot
     be found, returns None.
   """
-  if XSESSION_COMMAND is not None:
-    return XSESSION_COMMAND
-
   # If the session wrapper script (see below) is given a specific session as an
   # argument (such as ubuntu-2d on Ubuntu 12.04), the wrapper will run that
   # session instead of looking for custom .xsession files in the home directory.
   # So it's necessary to test for these files here.
   XSESSION_FILES = [
     "~/.chrome-remote-desktop-session",
     "~/.xsession",
     "~/.Xsession" ]
   for startup_file in XSESSION_FILES:
     startup_file = os.path.expanduser(startup_file)
@@ skipping 364 matching lines @@
 
       # Enforce minimum desktop size, as a sanity-check.  The limit of 100 will
       # detect typos of 2 instead of 3 digits.
       if width < 100 or height < 100:
         raise ValueError
     except ValueError:
       parser.error("Width and height should be 100 pixels or greater")
 
     sizes.append((width, height))
 
-  # Determine the command-line to run the user's preferred X environment.
-  global XSESSION_COMMAND
-  XSESSION_COMMAND = choose_x_session()
-  if XSESSION_COMMAND is None:
-    print >> sys.stderr, "Unable to choose suitable X session command."
-    return 1
-
-  if "--session=ubuntu-2d" in XSESSION_COMMAND:
-    print >> sys.stderr, (
-      "The Unity 2D desktop session will be used.\n"
-      "If you encounter problems with this choice of desktop, please install\n"
-      "the gnome-session-fallback package, and restart this script.\n")
-
   # Register an exit handler to clean up session process and the PID file.
   atexit.register(cleanup)
 
   # Load the initial host configuration.
   host_config = Config(options.config)
   if (not host_config.load()):
     print >> sys.stderr, "Failed to load " + config_filename
     return 1
 
   # Register handler to re-load the configuration in response to signals.
@@ skipping 157 matching lines @@
         host_config.clear_auth()
         host_config.clear_host_info()
         host_config.save()
         return 0
 
 
 if __name__ == "__main__":
   logging.basicConfig(level=logging.DEBUG,
                       format="%(asctime)s:%(levelname)s:%(message)s")
   sys.exit(main())