[PATCH v3 1/1] os: added the -upstart option for Upstart's signaling method.

[Oliver McFadden]

This is very similar to the RunFromSmartParent (implicit) option, except
we do not send the signal to our parent process, but our own process
instead, and that signal is SIGSTOP, not SIGUSR1.

Upstart will detect this, realize that we are ready to accept clients
now, send us SIGCONT and move our job status from SPAWNED to RUNNING.

Signed-off-by: Oliver McFadden <oliver.mcfadden at nokia.com>
---
v3: resend patch because it seems to have been idle for some time...
    - changed kill(getpid()) to raise().

 include/opaque.h |    1 +
 os/connection.c  |    5 +++++
 os/utils.c       |    5 +++++
 3 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/include/opaque.h b/include/opaque.h
index b3c7c70..f8c0000 100644
--- a/include/opaque.h
+++ b/include/opaque.h
@@ -55,6 +55,7 @@ extern _X_EXPORT int defaultBackingStore;
 extern _X_EXPORT Bool disableBackingStore;
 extern _X_EXPORT Bool enableBackingStore;
 extern _X_EXPORT Bool PartialNetwork;
+extern _X_EXPORT Bool RunFromUpstart;
 #ifndef NOLOGOHACK
 extern _X_EXPORT int logoScreenSaver;
 #endif
diff --git a/os/connection.c b/os/connection.c
index c143fb6..53f7f8c 100644
--- a/os/connection.c
+++ b/os/connection.c
@@ -146,6 +146,8 @@ Bool NewOutputPending;		/* not yet attempted to write some new output */
 Bool AnyClientsWriteBlocked;	/* true if some client blocked on write */
 
 static Bool RunFromSmartParent;	/* send SIGUSR1 to parent process */
+Bool RunFromUpstart;		/* send SIGSTOP to our own process;
+				   Upstart will send SIGCONT back. */
 Bool PartialNetwork;	/* continue even if unable to bind all addrs */
 static Pid_t ParentProcess;
 
@@ -357,6 +359,9 @@ NotifyParentProcess(void)
 	    kill (ParentProcess, SIGUSR1);
 	}
     }
+    if (RunFromUpstart) {
+	raise (SIGSTOP);
+    }
 #endif
 }
 
diff --git a/os/utils.c b/os/utils.c
index 51455cc..f176af4 100644
--- a/os/utils.c
+++ b/os/utils.c
@@ -527,6 +527,7 @@ void UseMsg(void)
 #endif
     ErrorF("-dumbSched             Disable smart scheduling, enable old behavior\n");
     ErrorF("-schedInterval int     Set scheduler interval in msec\n");
+    ErrorF("-upstart               Enable support for Upstart's signaling method\n");
     ErrorF("+extension name        Enable extension\n");
     ErrorF("-extension name        Disable extension\n");
 #ifdef XDMCP
@@ -922,6 +923,10 @@ ProcessCommandLine(int argc, char *argv[])
 	    else
 		UseMsg ();
 	}
+	else if ( strcmp( argv[i], "-upstart") == 0)
+	{
+	    RunFromUpstart = TRUE;
+	}
 	else if ( strcmp( argv[i], "+extension") == 0)
 	{
 	    if (++i < argc)
-- 
1.7.1.245.g7c42e