| """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() |
