Disable Me2Me host controls on unsupported Linux systems.

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.
@@ skipping 34 matching lines @@
 
 IS_INSTALLED = (os.path.basename(sys.argv[0]) != 'me2me_virtual_host.py')
 
 if IS_INSTALLED:
   HOST_BINARY_NAME = "chrome-remote-desktop-host"
 else:
   HOST_BINARY_NAME = "remoting_me2me_host"
 
 CHROME_REMOTING_GROUP_NAME = "chrome-remote-desktop"
 
-CONFIG_DIR = os.path.expanduser("~/.config/chrome-remote-desktop")
 HOME_DIR = os.environ["HOME"]
+CONFIG_DIR = HOME_DIR + "/.config/chrome-remote-desktop"
+SESSION_FILE_PATH = HOME_DIR + "/.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 load_lsb_release_file():
+  result = {}
+  try:
+    for line in open('/etc/lsb-release').readlines():
+      parts = (line.split('#', 2)[0]).split('=', 2)
+      if len(parts) == 2:
+        result[parts[0].strip()] = parts[1].strip()
+  except IOError as e:
+    logging.error('Failed to load /etc/lsb-release: ' + str(e))
+  return result
+
+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):
+    return True
+
+  # Currently the host supports only Goobuntu.
+  # TODO(sergeyu): Try other versions of Ubuntu and enable them here.
+  lsb_release = load_lsb_release_file()
+  return (lsb_release.has_key('GOOGLE_CODENAME') and
+      lsb_release['GOOGLE_CODENAME'] == 'precise')
+
 class Config:
   def __init__(self, path):
     self.path = path
     self.data = {}
     self.changed = False
 
   def load(self):
     """Loads the config from file.
 
     Raises:
@@ skipping 407 matching lines @@
     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 = [
-    "~/.chrome-remote-desktop-session",
+    SESSION_FILE_PATH,
     "~/.xsession",
     "~/.Xsession" ]
   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
@@ skipping 379 matching lines @@
                     "available (if the Xvfb server supports this).")
   parser.add_option("-f", "--foreground", dest="foreground", default=False,
                     action="store_true",
                     help="Don't run as a background daemon.")
   parser.add_option("", "--start", dest="start", default=False,
                     action="store_true",
                     help="Start the host.")
   parser.add_option("-k", "--stop", dest="stop", default=False,
                     action="store_true",
                     help="Stop the daemon currently running.")
+  parser.add_option("", "--get-status", dest="get_status", default=False,
+                    action="store_true",
+                    help="Prints host status")
   parser.add_option("", "--check-running", dest="check_running", default=False,
                     action="store_true",
                     help="Return 0 if the daemon is running, or 1 otherwise.")
   parser.add_option("", "--config", dest="config", action="store",
                     help="Use the specified configuration file.")
   parser.add_option("", "--reload", dest="reload", default=False,
                     action="store_true",
                     help="Signal currently running host to reload the config.")
   parser.add_option("", "--add-user", dest="add_user", default=False,
                     action="store_true",
                     help="Add current user to the chrome-remote-desktop group.")
   parser.add_option("", "--host-version", dest="host_version", default=False,
                     action="store_true",
                     help="Prints version of the host.")
   (options, args) = parser.parse_args()
 
   # Determine the filename of the host configuration and PID files.
   if not options.config:
     options.config = os.path.join(CONFIG_DIR, "host#%s.json" % g_host_hash)
 
   # Check for a modal command-line option (start, stop, etc.)
+
+  if options.get_status:
+    pid = get_daemon_pid()
+    if pid != 0:
+      print "STARTED"
+    elif is_supported_platform():
+      print "STOPPED"
+    else:
+      print "NOT_IMPLEMENTED"
+    return 0
+
+  # TODO(sergeyu): Remove --check-running once NPAPI plugin and NM host are
+  # updated to always use get-status flag instead.
   if options.check_running:
     pid = get_daemon_pid()
     return 0 if pid != 0 else 1
 
   if options.stop:
     pid = get_daemon_pid()
     if pid == 0:
       print "The daemon is not currently running"
     else:
       print "Killing process %s" % pid
@@ skipping 225 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())