Improve shutdown splash screen reliability

Right now the splash screen and rc script are
racing with each other so you occasionally see a few
shutdown messages before plymouth is up.

This commit ensures proper synchronization between prefdm,
plymouthd, and the rc script.

It does this by

1) fully stopping prefdm before letting rc start
2) fully starting plymouth before letting rc start
3) if prefdm is running (e.g. runlevel 5), waiting until it
   is fully stopped before starting plymouthd
4) if prefdm is not running (e.g. runlevel 3), starting
   plymouthd right away

One bit of complication in this commit is the "splash
manager".  It's a layer of indirection needed to handle the
conditional mentioned in 3) and 4).

There's no way within an upstart job file to say "start
after the prefdm "stopped" event only if prefdm is not already
stopped". We really need this to effectively happen, though,
because if prefdm isn't in the process of stopping (because
it was never started in the first place), it will never emit
the stopped event and blocking for an event that never comes
mean shutdown would never start.

The splash manager checks if prefdm is already running and
uses that information to emit an appropriate event that the
plymouth-shutdown job can key of off.

Note, one implication of 4) is we are showing plymouth when
shutting down from runlevel 3 now.  This is a change in
behavior, but makes sense, since we show plymouth when
starting up into runlevel 3.

3 files changed, 28 insertions, 14 deletions

diff --git a/init/plymouth-shutdown.conf b/init/plymouth-shutdown.conf
index e251286f..49010848 100644
--- a/init/plymouth-shutdown.conf
+++ b/init/plymouth-shutdown.conf
@@ -3,23 +3,14 @@
 # This service triggers plymouth to put up a splash
 # when leaving runlevel 5.
 
-start on stopped prefdm 
-task
+start on (splash-request IMMEDIATE=1) or (splash-request and stopped prefdm)
 
+task
 console output
 script
-        set $(runlevel || true)
-        if [ "$2" != "0" ] && [ "$2" != "6" ]; then
-		exit 0
-        fi
-
-        /sbin/plymouthd --mode=shutdown || exit 1
+        /sbin/plymouthd --mode="$MODE" || exit 1
         /bin/plymouth --sysinit
         /bin/plymouth --show-splash
-        if [ "$2" = "0" ]; then
-                /bin/plymouth message --text="Shutting down..."
-        elif [ "$2" = "6" ]; then
-                /bin/plymouth message --text="Restarting..."
-        fi
+        /bin/plymouth message --text="$MESSAGE"
 end script
 
diff --git a/init/prefdm.conf b/init/prefdm.conf
index d47356c7..701b8065 100644
--- a/init/prefdm.conf
+++ b/init/prefdm.conf
@@ -4,7 +4,7 @@
 
 start on stopped rc RUNLEVEL=5
 
-stop on runlevel [!5]
+stop on starting rc RUNLEVEL=[!5]
 
 console output
 respawn
diff --git a/init/splash-manager.conf b/init/splash-manager.conf
new file mode 100644
index 00000000..8e3299cf
--- /dev/null
+++ b/init/splash-manager.conf
@@ -0,0 +1,23 @@
+# splash-manager - requests splash screen
+#
+# This service emits a splash-request event when
+# its time to put up the plymouth splash
+
+start on starting rc RUNLEVEL=[06]
+task
+
+console output
+script
+        if [ "$RUNLEVEL" = "0" ]; then
+                MESSAGE=$"Shutting down..."
+        elif [ "$RUNLEVEL" = "6" ]; then
+                MESSAGE=$"Restarting..."
+        fi
+	initctl status prefdm 2>/dev/null > /tmp/cowcow
+        if cat /tmp/cowcow | grep -q stop/waiting; then
+                initctl emit splash-request IMMEDIATE=1 MODE=shutdown MESSAGE="$MESSAGE"
+        else
+                initctl emit splash-request MODE=shutdown MESSAGE="$MESSAGE"
+        fi
+end script
+