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# Test the signal module
from test.test_support import verbose, TestSkipped, TestFailed, vereq
import signal
import os, sys, time
if sys.platform[:3] in ('win', 'os2') or sys.platform=='riscos':
raise TestSkipped, "Can't test signal on %s" % sys.platform
MAX_DURATION = 20 # Entire test should last at most 20 sec.
if verbose:
x = '-x'
else:
x = '+x'
pid = os.getpid()
if verbose:
print("test runner's pid is", pid)
# Shell script that will send us asynchronous signals
script = """
(
set %(x)s
sleep 2
kill -HUP %(pid)d
sleep 2
kill -USR1 %(pid)d
sleep 2
kill -USR2 %(pid)d
) &
""" % vars()
a_called = b_called = False
def handlerA(*args):
global a_called
a_called = True
if verbose:
print("handlerA invoked", args)
class HandlerBCalled(Exception):
pass
def handlerB(*args):
global b_called
b_called = True
if verbose:
print("handlerB invoked", args)
raise HandlerBCalled, args
# Set up a child to send signals to us (the parent) after waiting long
# enough to receive the alarm. It seems we miss the alarm for some
# reason. This will hopefully stop the hangs on Tru64/Alpha.
# Alas, it doesn't. Tru64 appears to miss all the signals at times, or
# seemingly random subsets of them, and nothing done in force_test_exit
# so far has actually helped.
def force_test_exit():
# Sigh, both imports seem necessary to avoid errors.
import os
fork_pid = os.fork()
if fork_pid:
# In parent.
return fork_pid
# In child.
import os, time
try:
# Wait 5 seconds longer than the expected alarm to give enough
# time for the normal sequence of events to occur. This is
# just a stop-gap to try to prevent the test from hanging.
time.sleep(MAX_DURATION + 5)
print(' child should not have to kill parent', file=sys.__stdout__)
for signame in "SIGHUP", "SIGUSR1", "SIGUSR2", "SIGALRM":
os.kill(pid, getattr(signal, signame))
print(" child sent", signame, "to", pid, file=sys.__stdout__)
time.sleep(1)
finally:
os._exit(0)
# Install handlers.
hup = signal.signal(signal.SIGHUP, handlerA)
usr1 = signal.signal(signal.SIGUSR1, handlerB)
usr2 = signal.signal(signal.SIGUSR2, signal.SIG_IGN)
alrm = signal.signal(signal.SIGALRM, signal.default_int_handler)
try:
signal.alarm(MAX_DURATION)
vereq(signal.getsignal(signal.SIGHUP), handlerA)
vereq(signal.getsignal(signal.SIGUSR1), handlerB)
vereq(signal.getsignal(signal.SIGUSR2), signal.SIG_IGN)
vereq(signal.getsignal(signal.SIGALRM), signal.default_int_handler)
# Try to ensure this test exits even if there is some problem with alarm.
# Tru64/Alpha often hangs and is ultimately killed by the buildbot.
fork_pid = force_test_exit()
try:
signal.getsignal(4242)
raise TestFailed('expected ValueError for invalid signal # to '
'getsignal()')
except ValueError:
pass
try:
signal.signal(4242, handlerB)
raise TestFailed('expected ValueError for invalid signal # to '
'signal()')
except ValueError:
pass
try:
signal.signal(signal.SIGUSR1, None)
raise TestFailed('expected TypeError for non-callable')
except TypeError:
pass
# Launch an external script to send us signals.
# We expect the external script to:
# send HUP, which invokes handlerA to set a_called
# send USR1, which invokes handlerB to set b_called and raise
# HandlerBCalled
# send USR2, which is ignored
#
# Then we expect the alarm to go off, and its handler raises
# KeyboardInterrupt, finally getting us out of the loop.
os.system(script)
try:
print("starting pause() loop...")
while 1:
try:
if verbose:
print("call pause()...")
signal.pause()
if verbose:
print("pause() returned")
except HandlerBCalled:
if verbose:
print("HandlerBCalled exception caught")
except KeyboardInterrupt:
if verbose:
print("KeyboardInterrupt (the alarm() went off)")
if not a_called:
print('HandlerA not called')
if not b_called:
print('HandlerB not called')
finally:
# Forcibly kill the child we created to ping us if there was a test error.
try:
# Make sure we don't kill ourself if there was a fork error.
if fork_pid > 0:
os.kill(fork_pid, signal.SIGKILL)
except:
# If the child killed us, it has probably exited. Killing a
# non-existent process will raise an error which we don't care about.
pass
# Restore handlers.
signal.alarm(0) # cancel alarm in case we died early
signal.signal(signal.SIGHUP, hup)
signal.signal(signal.SIGUSR1, usr1)
signal.signal(signal.SIGUSR2, usr2)
signal.signal(signal.SIGALRM, alrm)
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