diff options
| -rw-r--r-- | Lib/test/test_signal.py | 93 | ||||
| -rw-r--r-- | Misc/NEWS | 3 | ||||
| -rw-r--r-- | Modules/signalmodule.c | 5 | ||||
| -rw-r--r-- | Python/pythonrun.c | 4 |
4 files changed, 87 insertions, 18 deletions
diff --git a/Lib/test/test_signal.py b/Lib/test/test_signal.py index a7c030e..6463f8e 100644 --- a/Lib/test/test_signal.py +++ b/Lib/test/test_signal.py @@ -255,48 +255,105 @@ class WakeupSignalTests(unittest.TestCase): class SiginterruptTest(unittest.TestCase): signum = signal.SIGUSR1 - def readpipe_interrupted(self, cb): + + def setUp(self): + """Install a no-op signal handler that can be set to allow + interrupts or not, and arrange for the original signal handler to be + re-installed when the test is finished. + """ + oldhandler = signal.signal(self.signum, lambda x,y: None) + self.addCleanup(signal.signal, self.signum, oldhandler) + + def readpipe_interrupted(self): + """Perform a read during which a signal will arrive. Return True if the + read is interrupted by the signal and raises an exception. Return False + if it returns normally. + """ + # Create a pipe that can be used for the read. Also clean it up + # when the test is over, since nothing else will (but see below for + # the write end). r, w = os.pipe() + self.addCleanup(os.close, r) + + # Create another process which can send a signal to this one to try + # to interrupt the read. ppid = os.getpid() pid = os.fork() - oldhandler = signal.signal(self.signum, lambda x,y: None) - cb() - if pid==0: - # child code: sleep, kill, sleep. and then exit, - # which closes the pipe from which the parent process reads + if pid == 0: + # Child code: sleep to give the parent enough time to enter the + # read() call (there's a race here, but it's really tricky to + # eliminate it); then signal the parent process. Also, sleep + # again to make it likely that the signal is delivered to the + # parent process before the child exits. If the child exits + # first, the write end of the pipe will be closed and the test + # is invalid. try: time.sleep(0.2) os.kill(ppid, self.signum) time.sleep(0.2) finally: + # No matter what, just exit as fast as possible now. exit_subprocess() - - try: + else: + # Parent code. + # Make sure the child is eventually reaped, else it'll be a + # zombie for the rest of the test suite run. + self.addCleanup(os.waitpid, pid, 0) + + # Close the write end of the pipe. The child has a copy, so + # it's not really closed until the child exits. We need it to + # close when the child exits so that in the non-interrupt case + # the read eventually completes, otherwise we could just close + # it *after* the test. os.close(w) + # Try the read and report whether it is interrupted or not to + # the caller. try: - d=os.read(r, 1) + d = os.read(r, 1) return False except OSError as err: if err.errno != errno.EINTR: raise return True - finally: - signal.signal(self.signum, oldhandler) - os.waitpid(pid, 0) def test_without_siginterrupt(self): - i=self.readpipe_interrupted(lambda: None) - self.assertEquals(i, True) + """If a signal handler is installed and siginterrupt is not called + at all, when that signal arrives, it interrupts a syscall that's in + progress. + """ + i = self.readpipe_interrupted() + self.assertTrue(i) + # Arrival of the signal shouldn't have changed anything. + i = self.readpipe_interrupted() + self.assertTrue(i) def test_siginterrupt_on(self): - i=self.readpipe_interrupted(lambda: signal.siginterrupt(self.signum, 1)) - self.assertEquals(i, True) + """If a signal handler is installed and siginterrupt is called with + a true value for the second argument, when that signal arrives, it + interrupts a syscall that's in progress. + """ + signal.siginterrupt(self.signum, 1) + i = self.readpipe_interrupted() + self.assertTrue(i) + # Arrival of the signal shouldn't have changed anything. + i = self.readpipe_interrupted() + self.assertTrue(i) def test_siginterrupt_off(self): - i=self.readpipe_interrupted(lambda: signal.siginterrupt(self.signum, 0)) - self.assertEquals(i, False) + """If a signal handler is installed and siginterrupt is called with + a false value for the second argument, when that signal arrives, it + does not interrupt a syscall that's in progress. + """ + signal.siginterrupt(self.signum, 0) + i = self.readpipe_interrupted() + self.assertFalse(i) + # Arrival of the signal shouldn't have changed anything. + i = self.readpipe_interrupted() + self.assertFalse(i) + + class ItimerTest(unittest.TestCase): def setUp(self): @@ -397,6 +397,9 @@ Library - Issue #4687: Fix accuracy of garbage collection runtimes displayed with gc.DEBUG_STATS. +- Issue #8354: The siginterrupt setting is now preserved for all signals, + not just SIGCHLD. + - Issue #7192: webbrowser.get("firefox") now wors on Mac OS X, as does webbrowser.get("safari"). diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c index 0039777..6437cb4 100644 --- a/Modules/signalmodule.c +++ b/Modules/signalmodule.c @@ -198,7 +198,12 @@ signal_handler(int sig_num) return; } #endif +#ifndef HAVE_SIGACTION + /* If the handler was not set up with sigaction, reinstall it. See + * Python/pythonrun.c for the implementation of PyOS_setsig which + * makes this true. See also issue8354. */ PyOS_setsig(sig_num, signal_handler); +#endif } diff --git a/Python/pythonrun.c b/Python/pythonrun.c index 225d178..05a10c6 100644 --- a/Python/pythonrun.c +++ b/Python/pythonrun.c @@ -2254,6 +2254,10 @@ PyOS_sighandler_t PyOS_setsig(int sig, PyOS_sighandler_t handler) { #ifdef HAVE_SIGACTION + /* Some code in Modules/signalmodule.c depends on sigaction() being + * used here if HAVE_SIGACTION is defined. Fix that if this code + * changes to invalidate that assumption. + */ struct sigaction context, ocontext; context.sa_handler = handler; sigemptyset(&context.sa_mask); |