Add systemwide session file for Chromoting

remoting/host/linux/linux_me2me_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.
@@ skipping 38 matching lines @@
 if IS_INSTALLED:
   HOST_BINARY_NAME = "chrome-remote-desktop-host"
 else:
   HOST_BINARY_NAME = "remoting_me2me_host"
 
 CHROME_REMOTING_GROUP_NAME = "chrome-remote-desktop"
 
 HOME_DIR = os.environ["HOME"]
 CONFIG_DIR = os.path.join(HOME_DIR, ".config/chrome-remote-desktop")
 SESSION_FILE_PATH = os.path.join(HOME_DIR, ".chrome-remote-desktop-session")
+SYSTEM_SESSION_FILE_PATH = "/etc/chrome-remote-desktop-session"
 
 X_LOCK_FILE_TEMPLATE = "/tmp/.X%d-lock"
 FIRST_X_DISPLAY_NUMBER = 20
 
 # Amount of time to wait between relaunching processes.
 SHORT_BACKOFF_TIME = 5
 LONG_BACKOFF_TIME = 60
 
 # How long a process must run in order not to be counted against the restart
 # thresholds.
 MINIMUM_PROCESS_LIFETIME = 60
 
 # Thresholds for switching from fast- to slow-restart and for giving up
 # trying to restart entirely.
 SHORT_BACKOFF_THRESHOLD = 5
 MAX_LAUNCH_FAILURES = SHORT_BACKOFF_THRESHOLD + 10
 
 # Globals needed by the atexit cleanup() handler.
 g_desktops = []
 g_host_hash = hashlib.md5(socket.gethostname()).hexdigest()
 
 def is_supported_platform():
   # Always assume that the system is supported if the config directory or
   # session file exist.
-  if os.path.isdir(CONFIG_DIR) or os.path.isfile(SESSION_FILE_PATH):
+  if (os.path.isdir(CONFIG_DIR) or os.path.isfile(SESSION_FILE_PATH) or
+      os.path.isfile(SYSTEM_SESSION_FILE_PATH)):
     return True
 
   # The host has been tested only on Ubuntu.
   distribution = platform.linux_distribution()
   return (distribution[0]).lower() == 'ubuntu'
 
 class Config:
   def __init__(self, path):
     self.path = path
     self.data = {}
@@ skipping 429 matching lines @@
 
 def choose_x_session():
   """Chooses the most appropriate X session command 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 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 = [
     SESSION_FILE_PATH,
-    "~/.xsession",
-    "~/.Xsession" ]
+    SYSTEM_SESSION_FILE_PATH ]
   for startup_file in XSESSION_FILES:
     startup_file = os.path.expanduser(startup_file)
     if os.path.exists(startup_file):
       # Use the same logic that a Debian system typically uses with ~/.xsession
       # (see /etc/X11/Xsession.d/50x11-common_determine-startup), to determine
       # exactly how to run this file.
       if os.access(startup_file, os.X_OK):
         # "/bin/sh -c" is smart about how to execute the session script and
         # works in cases where plain exec() fails (for example, if the file is
         # marked executable, but is a plain script with no shebang line).
@@ skipping 659 matching lines @@
         else:
           logging.info("Host exited with status %s." % os.WEXITSTATUS(status))
       elif os.WIFSIGNALED(status):
         logging.info("Host terminated by signal %s." % os.WTERMSIG(status))
 
 
 if __name__ == "__main__":
   logging.basicConfig(level=logging.DEBUG,
                       format="%(asctime)s:%(levelname)s:%(message)s")
   sys.exit(main())