Linux Chromoting: Explicitly kill all child processes on termination.

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 762 matching lines @@
   # Close the temporary file-descriptors.
   os.close(devnull_fd)
   os.close(log_fd)
 
 
 def cleanup():
   logging.info("Cleanup.")
 
   global g_desktops
   for desktop in g_desktops:
-    if desktop.x_proc:
-      logging.info("Terminating Xvfb")
-      desktop.x_proc.terminate()
+    for proc, name in [(desktop.x_proc, "Xvfb"),
+                       (desktop.session_proc, "session"),
+                       (desktop.host_proc, "host")]:
+      if proc is not None:
+        logging.info("Terminating " + name)
+        try:
+          psutil_proc = psutil.Process(proc.pid)
+          psutil_proc.terminate()
+
+          # Use a short timeout, to avoid delaying service shutdown if the
+          # process refuses to die for some reason.
+          psutil_proc.wait(timeout=10)

[rmsousa, 2014/10/10 00:50:27]

This will serialize the process terminations on this wait. Could we send SIGTERM
to the 3 first, then psutil.wait_procs on all 3 at once, then send sigkill to
the ones that are left?

[Lambros, 2014/10/10 01:12:15]

Nice idea, but probably too complicated to be worthwhile. Most of the time, this
should be quick anyway.

+        except psutil.TimeoutExpired:
+          logging.error("Timed out - sending SIGKILL")
+          psutil_proc.kill()
+        except psutil.Error:
+          logging.error("Error terminating process")
+
   g_desktops = []
   if ParentProcessLogger.instance():
     ParentProcessLogger.instance().release_parent()
 
 class SignalHandler:
   """Reload the config file on SIGHUP. Since we pass the configuration to the
   host processes via stdin, they can't reload it, so terminate them. They will
   be relaunched automatically with the new config."""
 
   def __init__(self, host_config):
@@ skipping 441 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())