EventLoop._do_poll: tweak EINTR handling

Silently handle EINTR, which is normal when we have received a signal
such as SIGINT. Also, raise StopIteration in order to break out of our
current iteration and respond appropriately to the signal as soon as
possible.

diff --git a/pym/portage/util/_eventloop/EventLoop.py b/pym/portage/util/_eventloop/EventLoop.py
index 6c6a1b75da7c4a6bfc0ace98d85f469ba8010a84..37839ab2d85dbdbef08a8273be135862c20ad1a4 100644 (file)
--- a/pym/portage/util/_eventloop/EventLoop.py
+++ b/pym/portage/util/_eventloop/EventLoop.py
@@ -1,6 +1,7 @@
 # Copyright 1999-2012 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
+import errno
 import logging
 import select
 import time
@@ -100,24 +101,23 @@ class EventLoop(object):
                        raise StopIteration(
                                "timeout is None and there are no poll() event handlers")
 
-               # The following error is known to occur with Linux kernel versions
-               # less than 2.6.24:
-               #
-               #   select.error: (4, 'Interrupted system call')
-               #
-               # This error has been observed after a SIGSTOP, followed by SIGCONT.
-               # Treat it similar to EAGAIN if timeout is None, otherwise just return
-               # without any events.
                while True:
                        try:
                                self._poll_event_queue.extend(self._poll_obj.poll(timeout))
                                break
                        except select.error as e:
-                               writemsg_level("\n!!! select error: %s\n" % (e,),
-                                       level=logging.ERROR, noiselevel=-1)
+                               # Silently handle EINTR, which is normal when we have
+                               # received a signal such as SIGINT.
+                               if not (e.args and e.args[0] == errno.EINTR):
+                                       writemsg_level("\n!!! select error: %s\n" % (e,),
+                                               level=logging.ERROR, noiselevel=-1)
                                del e
-                               if timeout is not None:
-                                       break
+
+                               # This typically means that we've received a SIGINT, so
+                               # raise StopIteration in order to break out of our current
+                               # iteration and respond appropriately to the signal as soon
+                               # as possible.
+                               raise StopIteration("interrupted")
 
        def _next_poll_event(self, timeout=None):
                """
@@ -170,7 +170,8 @@ class EventLoop(object):
                        except StopIteration:
                                # This could happen if there are no IO event handlers
                                # after _poll() calls _run_timeouts(), due to them
-                               # being removed by timeout or idle callbacks.
+                               # being removed by timeout or idle callbacks. It can
+                               # also be triggered by EINTR which is caused by signals.
                                events_handled += 1
 
                try: