mirror of
https://github.com/python/cpython.git
synced 2024-12-12 03:04:15 +08:00
e4f41deccf
To make sure there is no issue with code that is both Python 2 and 3 compatible, there are no plans to remove the module any sooner than Python 4 (unless the community moves to Python 3 solidly before then).
112 lines
3.7 KiB
Python
112 lines
3.7 KiB
Python
"""This test checks for correct fork() behavior.
|
|
"""
|
|
|
|
import _imp as imp
|
|
import os
|
|
import signal
|
|
import sys
|
|
import time
|
|
|
|
from test.fork_wait import ForkWait
|
|
from test.support import (run_unittest, reap_children, get_attribute,
|
|
import_module, verbose)
|
|
|
|
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_threaded_import_lock_fork(self):
|
|
"""Check fork() in main thread works while a subthread is doing an import"""
|
|
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:
|
|
# PyOS_BeforeFork should have waited for the import to complete
|
|
# before forking, so the child can recreate the import lock
|
|
# correctly, but also won't see a partially initialised module
|
|
if not pid:
|
|
m = __import__(fake_module_name)
|
|
if m == complete_module:
|
|
os._exit(0)
|
|
else:
|
|
if verbose > 1:
|
|
print("Child encountered partial module")
|
|
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_nested_import_lock_fork(self):
|
|
"""Check fork() in main thread works while the main thread is doing an import"""
|
|
# Issue 9573: this used to trigger RuntimeError in the child process
|
|
def fork_with_import_lock(level):
|
|
release = 0
|
|
in_child = False
|
|
try:
|
|
try:
|
|
for i in range(level):
|
|
imp.acquire_lock()
|
|
release += 1
|
|
pid = os.fork()
|
|
in_child = not pid
|
|
finally:
|
|
for i in range(release):
|
|
imp.release_lock()
|
|
except RuntimeError:
|
|
if in_child:
|
|
if verbose > 1:
|
|
print("RuntimeError in child")
|
|
os._exit(1)
|
|
raise
|
|
if in_child:
|
|
os._exit(0)
|
|
self.wait_impl(pid)
|
|
|
|
# Check this works with various levels of nested
|
|
# import in the main thread
|
|
for level in range(5):
|
|
fork_with_import_lock(level)
|
|
|
|
|
|
def test_main():
|
|
run_unittest(ForkTest)
|
|
reap_children()
|
|
|
|
if __name__ == "__main__":
|
|
test_main()
|