PEP 475: handle EINTR in the signal module

[vstinner]

BPO	23715
Nosy	@vstinner
Files	sigtimedwait_eintr.patch signal_eintr.patch

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2015-03-20.12:10:39.245>
created_at = <Date 2015-03-20.01:13:29.026>
labels = []
title = 'PEP 475: handle EINTR in the signal module'
updated_at = <Date 2015-03-27.13:36:01.527>
user = 'https://github.com/vstinner'

bugs.python.org fields:

activity = <Date 2015-03-27.13:36:01.527>
actor = 'python-dev'
assignee = 'none'
closed = True
closed_date = <Date 2015-03-20.12:10:39.245>
closer = 'vstinner'
components = []
creation = <Date 2015-03-20.01:13:29.026>
creator = 'vstinner'
dependencies = []
files = ['38583', '38588']
hgrepos = []
issue_num = 23715
keywords = ['patch']
message_count = 8.0
messages = ['238595', '238596', '238620', '238651', '238656', '238659', '238663', '239403']
nosy_count = 2.0
nosy_names = ['vstinner', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue23715'
versions = ['Python 3.5']

[vstinner]

Attached patch changes signal.sigtimedwait() to retry if sigtimedwait() failed with EINTR and the signal handler didn't raise an exception.

[vstinner]

It looks like signal.sigwaitinfo() can also fail with InterruptedError. It should also be modified.

[vstinner]

signal_eintr.py: More complete patch, modify also signal.sigwaitinfo().

--

I don't think that other signal functions need to be modified to handle EINTR.

POSIX manual pages:

• "The pthread_sigmask() function shall not return an error code of [EINTR]."
• "The pthread_kill() function shall not return an error code of [EINTR]."

pause() fails with EINTR when it receives a signal, but signal.pause() doesn't raise InterruptedError in this case, it only returns None, because we expect a signal.

I tested: signal.sigwait([]) doesn't fail with EINTR with a signal is received. No need to modify this function.

On Linux, signal.set_wakeup_fd() doesn't fail with InterruptedError.

[python-dev]

New changeset 33a6e2587aad by Victor Stinner in branch 'default':
Issue bpo-23715: signal.sigwaitinfo() and signal.sigtimedwait() are now retried
https://hg.python.org/cpython/rev/33a6e2587aad

[python-dev]

New changeset 8f9925a02fe7 by Victor Stinner in branch 'default':
Issue bpo-23715: Enhance test.script_helper to investigate test_eintr failure
https://hg.python.org/cpython/rev/8f9925a02fe7

[python-dev]

New changeset 79aed09a9fa5 by Victor Stinner in branch 'default':
Issue bpo-23715: Fix test_eintr, skip tests on signal.sigwaitinfo() and
https://hg.python.org/cpython/rev/79aed09a9fa5

[python-dev]

New changeset ed8c2a4a6d3d by Victor Stinner in branch 'default':
Issue bpo-23715: Fix test_script_helper
https://hg.python.org/cpython/rev/ed8c2a4a6d3d

[python-dev]

New changeset 35bc15fa4930 by Victor Stinner in branch 'default':
Issue bpo-23715: Fix test_sigtimedwait() of test_eintr
https://hg.python.org/cpython/rev/35bc15fa4930