diff --git a/pyudev/_util.py b/pyudev/_util.py index 266b161..3ce82b2 100644 --- a/pyudev/_util.py +++ b/pyudev/_util.py @@ -32,6 +32,7 @@ import os import sys import stat +import errno if sys.version_info[0] == 2: @@ -141,3 +142,37 @@ def get_device_type(filename): return 'block' else: raise ValueError('not a device file: {0!r}'.format(filename)) + + +def eintr_retry_call(func, *args, **kwargs): + """ + Handle interruptions to an interruptible system call. + + Run an interruptible system call in a loop and retry if it raises EINTR. + The signal calls that may raise EINTR prior to Python 3.5 are listed in + PEP 0475. Any calls to these functions must be wrapped in eintr_retry_call + in order to handle EINTR returns in older versions of Python. + + This function is safe to use under Python 3.5 and newer since the wrapped + function will simply return without raising EINTR. + + This function is based on _eintr_retry_call in python's subprocess.py. + """ + + # select.error inherits from Exception instead of OSError in Python 2 + import select + + while True: + try: + return func(*args, **kwargs) + except (OSError, IOError, select.error) as e: + # If this is not an IOError or OSError, it's the old select.error + # type, which means that the errno is only accessible via subscript + if isinstance(e, (OSError, IOError)): + error_code = e.errno + else: + error_code = e.args[0] + + if error_code == errno.EINTR: + continue + raise diff --git a/pyudev/monitor.py b/pyudev/monitor.py index b1eb71c..d87dc2c 100644 --- a/pyudev/monitor.py +++ b/pyudev/monitor.py @@ -36,7 +36,7 @@ import select from threading import Thread from contextlib import closing -from pyudev._util import ensure_byte_string, ensure_unicode_string, reraise +from pyudev._util import ensure_byte_string, ensure_unicode_string, reraise, eintr_retry_call from pyudev.core import Device @@ -328,7 +328,7 @@ class Monitor(object): with closing(select.epoll()) as notifier: notifier.register(self, select.EPOLLIN) while True: - events = notifier.poll() + events = eintr_retry_call(notifier.poll) for event in events: yield self.receive_device() @@ -399,7 +399,7 @@ class MonitorObserver(Thread): # and on the monitor notifier.register(self.monitor, select.EPOLLIN) while True: - for fd, _ in notifier.poll(): + for fd, _ in eintr_retry_call(notifier.poll): if fd == self._stop_event_source: # in case of a stop event, close our pipe side, and # return from the thread