| """This test checks for correct fork() behavior. | |
| """ | |
| import imp | |
| import os | |
| import signal | |
| import sys | |
| import time | |
| from test.fork_wait import ForkWait | |
| from test.test_support import run_unittest, reap_children, get_attribute, import_module | |
| threading = import_module('threading') | |
| #Skip test if fork does not exist. | |
| get_attribute(os, 'fork') | |
| class ForkTest(ForkWait): | |
| def wait_impl(self, cpid): | |
| for i in range(10): | |
| # waitpid() shouldn't hang, but some of the buildbots seem to hang | |
| # in the forking tests. This is an attempt to fix the problem. | |
| spid, status = os.waitpid(cpid, os.WNOHANG) | |
| if spid == cpid: | |
| break | |
| time.sleep(1.0) | |
| self.assertEqual(spid, cpid) | |
| self.assertEqual(status, 0, "cause = %d, exit = %d" % (status&0xff, status>>8)) | |
| def test_import_lock_fork(self): | |
| import_started = threading.Event() | |
| fake_module_name = "fake test module" | |
| partial_module = "partial" | |
| complete_module = "complete" | |
| def importer(): | |
| imp.acquire_lock() | |
| sys.modules[fake_module_name] = partial_module | |
| import_started.set() | |
| time.sleep(0.01) # Give the other thread time to try and acquire. | |
| sys.modules[fake_module_name] = complete_module | |
| imp.release_lock() | |
| t = threading.Thread(target=importer) | |
| t.start() | |
| import_started.wait() | |
| pid = os.fork() | |
| try: | |
| if not pid: | |
| m = __import__(fake_module_name) | |
| if m == complete_module: | |
| os._exit(0) | |
| else: | |
| os._exit(1) | |
| else: | |
| t.join() | |
| # Exitcode 1 means the child got a partial module (bad.) No | |
| # exitcode (but a hang, which manifests as 'got pid 0') | |
| # means the child deadlocked (also bad.) | |
| self.wait_impl(pid) | |
| finally: | |
| try: | |
| os.kill(pid, signal.SIGKILL) | |
| except OSError: | |
| pass | |
| def test_main(): | |
| run_unittest(ForkTest) | |
| reap_children() | |
| if __name__ == "__main__": | |
| test_main() |