248 lines
10 KiB
Python
248 lines
10 KiB
Python
"""PyUnit testing that threads honor our signal semantics"""
|
|
|
|
import unittest
|
|
import signal
|
|
import os
|
|
import sys
|
|
from test import support
|
|
import _thread as thread
|
|
import time
|
|
|
|
if (sys.platform[:3] == 'win'):
|
|
raise unittest.SkipTest("Can't test signal on %s" % sys.platform)
|
|
|
|
process_pid = os.getpid()
|
|
signalled_all=thread.allocate_lock()
|
|
|
|
USING_PTHREAD_COND = (sys.thread_info.name == 'pthread'
|
|
and sys.thread_info.lock == 'mutex+cond')
|
|
|
|
def registerSignals(for_usr1, for_usr2, for_alrm):
|
|
usr1 = signal.signal(signal.SIGUSR1, for_usr1)
|
|
usr2 = signal.signal(signal.SIGUSR2, for_usr2)
|
|
alrm = signal.signal(signal.SIGALRM, for_alrm)
|
|
return usr1, usr2, alrm
|
|
|
|
|
|
# The signal handler. Just note that the signal occurred and
|
|
# from who.
|
|
def handle_signals(sig,frame):
|
|
signal_blackboard[sig]['tripped'] += 1
|
|
signal_blackboard[sig]['tripped_by'] = thread.get_ident()
|
|
|
|
# a function that will be spawned as a separate thread.
|
|
def send_signals():
|
|
os.kill(process_pid, signal.SIGUSR1)
|
|
os.kill(process_pid, signal.SIGUSR2)
|
|
signalled_all.release()
|
|
|
|
class ThreadSignals(unittest.TestCase):
|
|
|
|
def test_signals(self):
|
|
with support.wait_threads_exit():
|
|
# Test signal handling semantics of threads.
|
|
# We spawn a thread, have the thread send two signals, and
|
|
# wait for it to finish. Check that we got both signals
|
|
# and that they were run by the main thread.
|
|
signalled_all.acquire()
|
|
self.spawnSignallingThread()
|
|
signalled_all.acquire()
|
|
|
|
# the signals that we asked the kernel to send
|
|
# will come back, but we don't know when.
|
|
# (it might even be after the thread exits
|
|
# and might be out of order.) If we haven't seen
|
|
# the signals yet, send yet another signal and
|
|
# wait for it return.
|
|
if signal_blackboard[signal.SIGUSR1]['tripped'] == 0 \
|
|
or signal_blackboard[signal.SIGUSR2]['tripped'] == 0:
|
|
try:
|
|
signal.alarm(1)
|
|
signal.pause()
|
|
finally:
|
|
signal.alarm(0)
|
|
|
|
self.assertEqual( signal_blackboard[signal.SIGUSR1]['tripped'], 1)
|
|
self.assertEqual( signal_blackboard[signal.SIGUSR1]['tripped_by'],
|
|
thread.get_ident())
|
|
self.assertEqual( signal_blackboard[signal.SIGUSR2]['tripped'], 1)
|
|
self.assertEqual( signal_blackboard[signal.SIGUSR2]['tripped_by'],
|
|
thread.get_ident())
|
|
signalled_all.release()
|
|
|
|
def spawnSignallingThread(self):
|
|
thread.start_new_thread(send_signals, ())
|
|
|
|
def alarm_interrupt(self, sig, frame):
|
|
raise KeyboardInterrupt
|
|
|
|
@unittest.skipIf(USING_PTHREAD_COND,
|
|
'POSIX condition variables cannot be interrupted')
|
|
@unittest.skipIf(sys.platform.startswith('linux') and
|
|
not sys.thread_info.version,
|
|
'Issue 34004: musl does not allow interruption of locks '
|
|
'by signals.')
|
|
# Issue #20564: sem_timedwait() cannot be interrupted on OpenBSD
|
|
@unittest.skipIf(sys.platform.startswith('openbsd'),
|
|
'lock cannot be interrupted on OpenBSD')
|
|
def test_lock_acquire_interruption(self):
|
|
# Mimic receiving a SIGINT (KeyboardInterrupt) with SIGALRM while stuck
|
|
# in a deadlock.
|
|
# XXX this test can fail when the legacy (non-semaphore) implementation
|
|
# of locks is used in thread_pthread.h, see issue #11223.
|
|
oldalrm = signal.signal(signal.SIGALRM, self.alarm_interrupt)
|
|
try:
|
|
lock = thread.allocate_lock()
|
|
lock.acquire()
|
|
signal.alarm(1)
|
|
t1 = time.monotonic()
|
|
self.assertRaises(KeyboardInterrupt, lock.acquire, timeout=5)
|
|
dt = time.monotonic() - t1
|
|
# Checking that KeyboardInterrupt was raised is not sufficient.
|
|
# We want to assert that lock.acquire() was interrupted because
|
|
# of the signal, not that the signal handler was called immediately
|
|
# after timeout return of lock.acquire() (which can fool assertRaises).
|
|
self.assertLess(dt, 3.0)
|
|
finally:
|
|
signal.alarm(0)
|
|
signal.signal(signal.SIGALRM, oldalrm)
|
|
|
|
@unittest.skipIf(USING_PTHREAD_COND,
|
|
'POSIX condition variables cannot be interrupted')
|
|
@unittest.skipIf(sys.platform.startswith('linux') and
|
|
not sys.thread_info.version,
|
|
'Issue 34004: musl does not allow interruption of locks '
|
|
'by signals.')
|
|
# Issue #20564: sem_timedwait() cannot be interrupted on OpenBSD
|
|
@unittest.skipIf(sys.platform.startswith('openbsd'),
|
|
'lock cannot be interrupted on OpenBSD')
|
|
def test_rlock_acquire_interruption(self):
|
|
# Mimic receiving a SIGINT (KeyboardInterrupt) with SIGALRM while stuck
|
|
# in a deadlock.
|
|
# XXX this test can fail when the legacy (non-semaphore) implementation
|
|
# of locks is used in thread_pthread.h, see issue #11223.
|
|
oldalrm = signal.signal(signal.SIGALRM, self.alarm_interrupt)
|
|
try:
|
|
rlock = thread.RLock()
|
|
# For reentrant locks, the initial acquisition must be in another
|
|
# thread.
|
|
def other_thread():
|
|
rlock.acquire()
|
|
|
|
with support.wait_threads_exit():
|
|
thread.start_new_thread(other_thread, ())
|
|
# Wait until we can't acquire it without blocking...
|
|
while rlock.acquire(blocking=False):
|
|
rlock.release()
|
|
time.sleep(0.01)
|
|
signal.alarm(1)
|
|
t1 = time.monotonic()
|
|
self.assertRaises(KeyboardInterrupt, rlock.acquire, timeout=5)
|
|
dt = time.monotonic() - t1
|
|
# See rationale above in test_lock_acquire_interruption
|
|
self.assertLess(dt, 3.0)
|
|
finally:
|
|
signal.alarm(0)
|
|
signal.signal(signal.SIGALRM, oldalrm)
|
|
|
|
def acquire_retries_on_intr(self, lock):
|
|
self.sig_recvd = False
|
|
def my_handler(signal, frame):
|
|
self.sig_recvd = True
|
|
|
|
old_handler = signal.signal(signal.SIGUSR1, my_handler)
|
|
try:
|
|
def other_thread():
|
|
# Acquire the lock in a non-main thread, so this test works for
|
|
# RLocks.
|
|
lock.acquire()
|
|
# Wait until the main thread is blocked in the lock acquire, and
|
|
# then wake it up with this.
|
|
time.sleep(0.5)
|
|
os.kill(process_pid, signal.SIGUSR1)
|
|
# Let the main thread take the interrupt, handle it, and retry
|
|
# the lock acquisition. Then we'll let it run.
|
|
time.sleep(0.5)
|
|
lock.release()
|
|
|
|
with support.wait_threads_exit():
|
|
thread.start_new_thread(other_thread, ())
|
|
# Wait until we can't acquire it without blocking...
|
|
while lock.acquire(blocking=False):
|
|
lock.release()
|
|
time.sleep(0.01)
|
|
result = lock.acquire() # Block while we receive a signal.
|
|
self.assertTrue(self.sig_recvd)
|
|
self.assertTrue(result)
|
|
finally:
|
|
signal.signal(signal.SIGUSR1, old_handler)
|
|
|
|
def test_lock_acquire_retries_on_intr(self):
|
|
self.acquire_retries_on_intr(thread.allocate_lock())
|
|
|
|
def test_rlock_acquire_retries_on_intr(self):
|
|
self.acquire_retries_on_intr(thread.RLock())
|
|
|
|
def test_interrupted_timed_acquire(self):
|
|
# Test to make sure we recompute lock acquisition timeouts when we
|
|
# receive a signal. Check this by repeatedly interrupting a lock
|
|
# acquire in the main thread, and make sure that the lock acquire times
|
|
# out after the right amount of time.
|
|
# NOTE: this test only behaves as expected if C signals get delivered
|
|
# to the main thread. Otherwise lock.acquire() itself doesn't get
|
|
# interrupted and the test trivially succeeds.
|
|
self.start = None
|
|
self.end = None
|
|
self.sigs_recvd = 0
|
|
done = thread.allocate_lock()
|
|
done.acquire()
|
|
lock = thread.allocate_lock()
|
|
lock.acquire()
|
|
def my_handler(signum, frame):
|
|
self.sigs_recvd += 1
|
|
old_handler = signal.signal(signal.SIGUSR1, my_handler)
|
|
try:
|
|
def timed_acquire():
|
|
self.start = time.monotonic()
|
|
lock.acquire(timeout=0.5)
|
|
self.end = time.monotonic()
|
|
def send_signals():
|
|
for _ in range(40):
|
|
time.sleep(0.02)
|
|
os.kill(process_pid, signal.SIGUSR1)
|
|
done.release()
|
|
|
|
with support.wait_threads_exit():
|
|
# Send the signals from the non-main thread, since the main thread
|
|
# is the only one that can process signals.
|
|
thread.start_new_thread(send_signals, ())
|
|
timed_acquire()
|
|
# Wait for thread to finish
|
|
done.acquire()
|
|
# This allows for some timing and scheduling imprecision
|
|
self.assertLess(self.end - self.start, 2.0)
|
|
self.assertGreater(self.end - self.start, 0.3)
|
|
# If the signal is received several times before PyErr_CheckSignals()
|
|
# is called, the handler will get called less than 40 times. Just
|
|
# check it's been called at least once.
|
|
self.assertGreater(self.sigs_recvd, 0)
|
|
finally:
|
|
signal.signal(signal.SIGUSR1, old_handler)
|
|
|
|
|
|
def test_main():
|
|
global signal_blackboard
|
|
|
|
signal_blackboard = { signal.SIGUSR1 : {'tripped': 0, 'tripped_by': 0 },
|
|
signal.SIGUSR2 : {'tripped': 0, 'tripped_by': 0 },
|
|
signal.SIGALRM : {'tripped': 0, 'tripped_by': 0 } }
|
|
|
|
oldsigs = registerSignals(handle_signals, handle_signals, handle_signals)
|
|
try:
|
|
support.run_unittest(ThreadSignals)
|
|
finally:
|
|
registerSignals(*oldsigs)
|
|
|
|
if __name__ == '__main__':
|
|
test_main()
|