def do_fork_and_wait():
# just fork a child process and wait it
pid = os.fork()
if pid > 0:
support.wait_process(pid, exitcode=50)
else:
os._exit(50)
def test_forkinthread(self):
pid = None
def fork_thread(read_fd, write_fd):
nonlocal pid
# fork in a thread
pid = os.fork()
if pid:
# parent process
return
# child process
try:
os.close(read_fd)
os.write(write_fd, b"OK")
finally:
os._exit(0)
with support.wait_threads_exit():
thread.start_new_thread(fork_thread, (self.read_fd, self.write_fd))
self.assertEqual(os.read(self.read_fd, 2), b"OK")
os.close(self.write_fd)
self.assertIsNotNone(pid)
support.wait_process(pid, exitcode=0)
def test_fork(self):
# check that tracemalloc is still working after fork
pid = os.fork()
if not pid:
# child
exitcode = 1
try:
exitcode = self.fork_child()
finally:
os._exit(exitcode)
else:
support.wait_process(pid, exitcode=0)
def test_mac_ver_with_fork(self):
# Issue7895: platform.mac_ver() crashes when using fork without exec
#
# This test checks that the fix for that issue works.
#
pid = os.fork()
if pid == 0:
# child
info = platform.mac_ver()
os._exit(0)
else:
# parent
support.wait_process(pid, exitcode=0)
def test_is_alive_after_fork(self):
# Try hard to trigger #18418: is_alive() could sometimes be True on
# threads that vanished after a fork.
old_interval = sys.getswitchinterval()
self.addCleanup(sys.setswitchinterval, old_interval)
# Make the bug more likely to manifest.
test.support.setswitchinterval(1e-6)
for i in range(20):
t = threading.Thread(target=lambda: None)
t.start()
pid = os.fork()
if pid == 0:
os._exit(11 if t.is_alive() else 10)
else:
t.join()
support.wait_process(pid, exitcode=10)
def testIssue8621(self):
# On at least some versions of OSX self.uuid.uuid4 generates
# the same sequence of UUIDs in the parent and any
# children started using fork.
fds = os.pipe()
pid = os.fork()
if pid == 0:
os.close(fds[0])
value = self.uuid.uuid4()
os.write(fds[1], value.hex.encode('latin-1'))
os._exit(0)
else:
os.close(fds[1])
self.addCleanup(os.close, fds[0])
parent_value = self.uuid.uuid4().hex
support.wait_process(pid, exitcode=0)
child_value = os.read(fds[0], 100).decode('latin-1')
self.assertNotEqual(parent_value, child_value)
def test_after_fork(self):
# Test the global Random instance gets reseeded in child
r, w = os.pipe()
pid = os.fork()
if pid == 0:
# child process
try:
val = random.getrandbits(128)
with open(w, "w") as f:
f.write(str(val))
finally:
os._exit(0)
else:
# parent process
os.close(w)
val = random.getrandbits(128)
with open(r, "r") as f:
child_val = eval(f.read())
self.assertNotEqual(val, child_val)
support.wait_process(pid, exitcode=0)
def test_clear_threads_states_after_fork(self):
# Issue #17094: check that threads states are cleared after fork()
# start a bunch of threads
threads = []
for i in range(16):
t = threading.Thread(target=lambda: time.sleep(0.3))
threads.append(t)
t.start()
pid = os.fork()
if pid == 0:
# check that threads states have been cleared
if len(sys._current_frames()) == 1:
os._exit(51)
else:
os._exit(52)
else:
support.wait_process(pid, exitcode=51)
for t in threads:
t.join()
def wait_impl(self, cpid):
support.wait_process(cpid, exitcode=0)
