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Merged revisions 81016 via svnmerge from 

svn+ssh://pythondev@svn.python.org/python/branches/py3k

................
  r81016 | jean-paul.calderone | 2010-05-08 23:18:57 -0400 (Sat, 08 May 2010) | 9 lines

  Merged revisions 81007 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r81007 | jean-paul.calderone | 2010-05-08 16:06:02 -0400 (Sat, 08 May 2010) | 1 line

    Skip signal handler re-installation if it is not necessary.  Issue 8354.
  ........
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This commit is contained in:
Jean-Paul Calderone 2010-05-09 03:25:16 +00:00
parent f7c8902de2
commit 9c39bc7265
4 changed files with 86 additions and 17 deletions
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87
Lib/test/test_signal.py
View File

@ -255,26 +255,61 @@ 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
# 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()
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)
try:
# 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)
return False
@ -282,21 +317,43 @@ class SiginterruptTest(unittest.TestCase):
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):

3
Misc/NEWS
View File

@ -73,6 +73,9 @@ 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 #8464: tarfile no longer creates files with execute permissions set
when mode="w|" is used.

5
Modules/signalmodule.c
View File

@ -192,7 +192,12 @@ 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
}

4
Python/pythonrun.c
View File

@ -2237,6 +2237,10 @@ 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);