Terminate preforked process if the parent terminates abruptly

waflib/extras/prefork.py

@@ -25,7 +25,7 @@ To use::
 The servers and the build process are using a shared nonce to prevent undesirable external connections.
 """
 
-import os, re, socket, threading, sys, subprocess, time, atexit, traceback, random
+import os, re, socket, threading, sys, subprocess, time, atexit, traceback, random, signal
 try:
 	import SocketServer
 except ImportError:
@@ -157,6 +157,23 @@ def create_server(conn, cls):
 	SHARED_KEY = os.environ['SHARED_KEY']
 	os.environ['SHARED_KEY'] = ''
 
+	ppid = int(os.environ['PREFORKPID'])
+	def reap():
+		if os.sep != '/':
+			os.waitpid(ppid, 0)
+		else:
+			while 1:
+				try:
+					os.kill(ppid, 0)
+				except OSError:
+					break
+				else:
+					time.sleep(1)
+		os.kill(os.getpid(), signal.SIGKILL)
+	t = threading.Thread(target=reap)
+	t.setDaemon(True)
+	t.start()
+
 	SocketServer.TCPServer.allow_reuse_address = True
 	server = SocketServer.TCPServer(conn, req)
 	#server.timeout = 6000 # seconds
@@ -338,6 +355,8 @@ else:
 		except KeyError:
 			key = "".join([chr(random.SystemRandom().randint(40, 126)) for x in range(20)])
 			os.environ['SHARED_KEY'] = ctx.SHARED_KEY = key
+
+		os.environ['PREFORKPID'] = str(os.getpid())
 		return key
 
 	def init_servers(ctx, maxval):
@@ -357,6 +376,9 @@ else:
 					time.sleep(0.01)
 			if not conn:
 				raise ValueError('Could not start the server!')
+			if srv.poll() is not None:
+				Logs.warn('Looks like it it not our server process - concurrent builds are unsupported at this stage')
+				raise ValueError('Could not start the server')
 			CONNS.append(conn)
 
 	def init_smp(self):

waflib/extras/preforkjava.py

@@ -2,6 +2,8 @@
 # encoding: utf-8
 # Thomas Nagy, 2015 (ita)
 
+# TODO: have the child process terminate if the parent is killed abruptly
+
 import os, re, socket, threading, sys, subprocess, time, atexit, traceback, random
 try:
 	import SocketServer
@@ -187,6 +189,7 @@ if 1:
 		except KeyError:
 			key = "".join([chr(random.SystemRandom().randint(40, 126)) for x in range(20)])
 			os.environ['SHARED_KEY'] = ctx.SHARED_KEY = key
+		os.environ['PREFORKPID'] = str(os.getpid())
 		return key
 
 	def init_servers(ctx, maxval):

waflib/extras/preforkunix.py

@@ -19,7 +19,7 @@ To use::
         more code
 """
 
-import os, re, socket, threading, sys, subprocess, atexit, traceback
+import os, re, socket, threading, sys, subprocess, atexit, traceback, signal, time
 try:
 	from queue import Queue
 except ImportError:
@@ -136,9 +136,25 @@ if 1:
 
 	def make_conn(bld):
 		child_socket, parent_socket = socket.socketpair(socket.AF_UNIX)
+		ppid = os.getpid()
 		pid = os.fork()
 		if pid == 0:
 			parent_socket.close()
+
+			# if the parent crashes, try to exit cleanly
+			def reap():
+				while 1:
+					try:
+						os.kill(ppid, 0)
+					except OSError:
+						break
+					else:
+						time.sleep(1)
+				os.kill(os.getpid(), signal.SIGKILL)
+			t = threading.Thread(target=reap)
+			t.setDaemon(True)
+			t.start()
+
 			# write to child_socket only
 			try:
 				while 1: