[gdm] Make gdm-session-worker exit cleanly

[Ray Strode <halfline src gnome org>]

commit 187180220ff6179419a2333c0cb1d57818f28854
Author: João Paulo Rechi Vita <jprvita endlessm com>
Date:   Fri Jul 10 12:52:04 2015 -0400

    Make gdm-session-worker exit cleanly
    
    Calling gdm_session_stop_conversation() in gdm_launch_environment_stop()
    sends a SIGTERM to gdm-session-worker without waiting for it to die. The
    next step is calling gdm_session_close() to close the session, which
    stops all conversations of that session object, sending a 2nd SIGTERM to
    gdm-session-worker, this time waiting on its PID.
    
    On gdm-session-worker side, the first SIGTERM is caught by
    on_shutdown_signal(), its custom SIGTERM handler, which quits the
    mainloop and unrefs the worker object. Quiting the mainloop replaces the
    custom SIGTERM handler with the system default one (exit immediately).
    During the worker object class finalization gdm-session-worker may
    receive the 2nd SIGTERM, which leads to its immediate termination,
    without waiting for its children, which in turn leads to the main gdm
    process exit.
    
    Since systemd relies on the SIGCHLD from the main gdm process to tell
    when the service has stopped, this behavior breaks any unit that has a
    Conflicts=gdm.service entry and relies on the X server not being around
    when it is started.
    
    This commit removes the call to gdm_session_stop_conversation() in
    gdm_launch_environment_stop() and leaves it to be stopped in
    gdm_session_close().
    
    [endlessm/eos-shell#4921]
    
    https://bugzilla.gnome.org/show_bug.cgi?id=752388

 daemon/gdm-launch-environment.c |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/daemon/gdm-launch-environment.c b/daemon/gdm-launch-environment.c
index ec29d90..1beceea 100644
--- a/daemon/gdm-launch-environment.c
+++ b/daemon/gdm-launch-environment.c
@@ -422,7 +422,6 @@ gdm_launch_environment_stop (GdmLaunchEnvironment *launch_environment)
         }
 
         if (launch_environment->priv->session != NULL) {
-                gdm_session_stop_conversation (launch_environment->priv->session, "gdm-launch-environment");
                 gdm_session_close (launch_environment->priv->session);
 
                 g_clear_object (&launch_environment->priv->session);