greenio: fix fd double close; Thanks to Antonio Cuni

https://github.com/eventlet/eventlet/issues/219

eventlet/greenio/py2.py

@@ -143,7 +143,9 @@ class _SocketDuckForFd(object):
             raise
 
     def _mark_as_closed(self):
+        current = self._closed
         self._closed = True
+        return current
 
     @property
     def _sock(self):
@@ -201,8 +203,10 @@ class _SocketDuckForFd(object):
         self._close()
 
     def _close(self):
+        was_closed = self._mark_as_closed()
+        if was_closed:
+            return
         notify_close(self._fileno)
-        self._mark_as_closed()
         try:
             os.close(self._fileno)
         except:

eventlet/greenio/py3.py

@@ -127,8 +127,8 @@ class GreenFileIO(_OriginalIOBase):
 
     def close(self):
         if not self._closed:
-            _original_os.close(self._fileno)
             self._closed = True
+            _original_os.close(self._fileno)
         notify_close(self._fileno)
         for method in [
                 'fileno', 'flush', 'isatty', 'next', 'read', 'readinto',

tests/greenio_test.py

@@ -15,10 +15,7 @@ from eventlet import event, greenio, debug
 from eventlet.hubs import get_hub
 from eventlet.green import select, socket, time, ssl
 from eventlet.support import capture_stderr, get_errno, six
-from tests import (
+import tests
-    LimitedTestCase, main,
-    skip_with_pyevent, skipped, skip_if, skip_on_windows,
-)
 
 
 if six.PY3:
@@ -58,7 +55,7 @@ def using_kqueue_hub(_f):
         return False
 
 
-class TestGreenSocket(LimitedTestCase):
+class TestGreenSocket(tests.LimitedTestCase):
     def assertWriteToClosedFileRaises(self, fd):
         if sys.version_info[0] < 3:
             # 2.x socket._fileobjects are odd: writes don't check
@@ -481,7 +478,7 @@ class TestGreenSocket(LimitedTestCase):
         server.close()
         client.close()
 
-    @skip_with_pyevent
+    @tests.skip_with_pyevent
     def test_raised_multiple_readers(self):
         debug.hub_prevent_multiple_readers(True)
 
@@ -503,9 +500,9 @@ class TestGreenSocket(LimitedTestCase):
         s.sendall(b'b')
         a.wait()
 
-    @skip_with_pyevent
+    @tests.skip_with_pyevent
-    @skip_if(using_epoll_hub)
+    @tests.skip_if(using_epoll_hub)
-    @skip_if(using_kqueue_hub)
+    @tests.skip_if(using_kqueue_hub)
     def test_closure(self):
         def spam_to_me(address):
             sock = eventlet.connect(address)
@@ -655,8 +652,8 @@ def test_get_fileno_of_a_socket_with_fileno_returning_wrong_type_fails():
         assert False, 'Expected TypeError not raised'
 
 
-class TestGreenPipe(LimitedTestCase):
+class TestGreenPipe(tests.LimitedTestCase):
-    @skip_on_windows
+    @tests.skip_on_windows
     def setUp(self):
         super(self.__class__, self).setUp()
         self.tempdir = tempfile.mkdtemp('_green_pipe_test')
@@ -768,10 +765,10 @@ class TestGreenPipe(LimitedTestCase):
         self.assertEqual(f.tell(), 9)
 
 
-class TestGreenIoLong(LimitedTestCase):
+class TestGreenIoLong(tests.LimitedTestCase):
     TEST_TIMEOUT = 10  # the test here might take a while depending on the OS
 
-    @skip_with_pyevent
+    @tests.skip_with_pyevent
     def test_multiple_readers(self, clibufsize=False):
         debug.hub_prevent_multiple_readers(False)
         recvsize = 2 * min_buf_size()
@@ -824,21 +821,21 @@ class TestGreenIoLong(LimitedTestCase):
         assert len(results2) > 0
         debug.hub_prevent_multiple_readers()
 
-    @skipped  # by rdw because it fails but it's not clear how to make it pass
+    @tests.skipped  # by rdw because it fails but it's not clear how to make it pass
-    @skip_with_pyevent
+    @tests.skip_with_pyevent
     def test_multiple_readers2(self):
         self.test_multiple_readers(clibufsize=True)
 
 
-class TestGreenIoStarvation(LimitedTestCase):
+class TestGreenIoStarvation(tests.LimitedTestCase):
     # fixme: this doesn't succeed, because of eventlet's predetermined
     # ordering.  two processes, one with server, one with client eventlets
     # might be more reliable?
 
     TEST_TIMEOUT = 300  # the test here might take a while depending on the OS
 
-    @skipped  # by rdw, because it fails but it's not clear how to make it pass
+    @tests.skipped  # by rdw, because it fails but it's not clear how to make it pass
-    @skip_with_pyevent
+    @tests.skip_with_pyevent
     def test_server_starvation(self, sendloops=15):
         recvsize = 2 * min_buf_size()
         sendsize = 10000 * recvsize
@@ -955,5 +952,5 @@ def test_socket_del_fails_gracefully_when_not_fully_initialized():
     assert err.getvalue() == ''
 
 
-if __name__ == '__main__':
+def test_double_close_219():
-    main()
+    tests.run_isolated('greenio_double_close_219.py')

tests/isolated/greenio_double_close_219.py

@@ -0,0 +1,22 @@
+__test__ = False
+
+
+def main():
+    import eventlet
+    eventlet.monkey_patch()
+    import subprocess
+    import gc
+
+    p = subprocess.Popen(['ls'], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    # the following line creates a _SocketDuckForFd(3) and .close()s it, but the
+    # object has not been collected by the GC yet
+    p.communicate()
+
+    f = open('/dev/null', 'rb')    # f.fileno() == 3
+    gc.collect() # this calls the __del__ of _SocketDuckForFd(3), close()ing it again
+
+    f.close() # OSError, because the fd 3 has already been closed
+    print('pass')
+
+if __name__ == '__main__':
+    main()