Add threadframe and TracebackUtils.py so we can get tracebacks of dbus deadlocks

sugar/Makefile.am

@@ -8,6 +8,7 @@ sugar_PYTHON =				\
 	env.py				\
 	logger.py			\
 	setup.py			\
+	TracebackUtils.py	\
 	util.py
 
 EXTRA_DIST = __uninstalled__.py

sugar/TracebackUtils.py

@@ -0,0 +1,37 @@
+import sys
+import traceback
+import os
+import signal
+
+haveThreadframe = True
+try:
+	import threadframe
+except ImportError:
+	haveThreadframe = False
+
+class TracebackHelper(object):
+	def __init__(self):
+		fname = "%s-%d" % (os.path.basename(sys.argv[0]), os.getpid())
+		self._fpath = os.path.join("/tmp", fname)
+		print "Tracebacks will be written to %s on SIGUSR1" % self._fpath
+		signal.signal(signal.SIGUSR1, self._handler)
+
+	def __del__(self):
+		try:
+			os.remove(self._fpath)
+		except OSError:
+			pass
+
+	def _handler(self, signum, pframe):
+		f = open(self._fpath, "a")
+		if not haveThreadframe:
+			f.write("Threadframe not installed.  No traceback available.\n")
+		else:
+			frames = threadframe.dict()
+			for thread_id, frame in frames.iteritems():
+				f.write(('-' * 79) + '\n')
+				f.write('[Thread %s] %d' % (thread_id, sys.getrefcount(frame)) + '\n')
+				traceback.print_stack(frame, limit=None, file=f)
+				f.write("\n")
+		f.write('\n')
+		f.close()