1# Copyright 2016 The Android Open Source Project 2# 3# Licensed under the Apache License, Version 2.0 (the "License"); 4# you may not use this file except in compliance with the License. 5# You may obtain a copy of the License at 6# 7# http://www.apache.org/licenses/LICENSE-2.0 8# 9# Unless required by applicable law or agreed to in writing, software 10# distributed under the License is distributed on an "AS IS" BASIS, 11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12# See the License for the specific language governing permissions and 13# limitations under the License. 14 15"""Signal related functionality.""" 16 17import os 18import signal 19import sys 20 21_path = os.path.realpath(__file__ + '/../..') 22if sys.path[0] != _path: 23 sys.path.insert(0, _path) 24del _path 25 26 27def relay_signal(handler, signum, frame): 28 """Notify a listener returned from getsignal of receipt of a signal. 29 30 Returns: 31 True if it was relayed to the target, False otherwise. 32 False in particular occurs if the target isn't relayable. 33 """ 34 if handler in (None, signal.SIG_IGN): 35 return True 36 if handler == signal.SIG_DFL: 37 # This scenario is a fairly painful to handle fully, thus we just 38 # state we couldn't handle it and leave it to client code. 39 return False 40 handler(signum, frame) 41 return True 42