bitbake: bitbake-worker: Gracefully handle SIGTERM

Currently if bitbake-worker handles a SIGTERM, it leaves the child
processes to complete or hang. It shouldn't do this so hook the SIGTERM
event and gracefully shutdown any children.

(Bitbake rev: 551406f3f9ee94de09d2da6e16fea054c6dbfdb7)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/bin/bitbake-worker

@@ -242,6 +242,14 @@ class BitbakeWorker(object):
         self.build_pids = {}
         self.build_pipes = {}
     
+        signal.signal(signal.SIGTERM, self.sigterm_exception)
+
+    def sigterm_exception(self, signum, stackframe):
+        bb.warn("Worker recieved SIGTERM, shutting down...")
+        self.handle_finishnow(None)
+        signal.signal(signal.SIGTERM, signal.SIG_DFL)
+        os.kill(os.getpid(), signal.SIGTERM)
+
     def serve(self):        
         while True:
             (ready, _, _) = select.select([self.input] + [i.input for i in self.build_pipes.values()], [] , [], 1)