Merge branch '1.17' into 2.0

dev-requirements.txt

@@ -1,8 +1,8 @@
 # Older junk
 tox>=1.4,<1.5
 # For newer tasks like building Sphinx docs.
-invoke>=0.11.1,<2.0
-invocations>=0.11.0,<2.0
+invoke>=0.13,<2.0
+invocations>=0.13,<2.0
 sphinx>=1.1.3,<2.0
 alabaster>=0.7.5,<2.0
 releases>=1.1.0,<2.0

paramiko/buffered_pipe.py

@@ -70,11 +70,20 @@ def set_event(self, event):
         
         :param threading.Event event: the event to set/clear
         """
-        self._event = event
-        if len(self._buffer) > 0:
-            event.set()
-        else:
-            event.clear()
+        self._lock.acquire()
+        try:
+            self._event = event
+            # Make sure the event starts in `set` state if we appear to already
+            # be closed; otherwise, if we start in `clear` state & are closed,
+            # nothing will ever call `.feed` and the event (& OS pipe, if we're
+            # wrapping one - see `Channel.fileno`) will permanently stay in
+            # `clear`, causing deadlock if e.g. `select`ed upon.
+            if self._closed or len(self._buffer) > 0:
+                event.set()
+            else:
+                event.clear()
+        finally:
+            self._lock.release()
 
     def feed(self, data):
         """

sites/www/changelog.rst

@@ -2,6 +2,13 @@
 Changelog
 =========
 
+* :bug:`537` Fix a bug in `BufferedPipe.set_event
+  <paramiko.buffered_pipe.BufferedPipe.set_event>` which could cause
+  deadlocks/hangs when one uses `select.select` against
+  `~paramiko.channel.Channel` objects (or otherwise calls `Channel.fileno
+  <paramiko.channel.Channel.fileno>` after the channel has closed). Thanks to
+  Przemysław Strzelczak for the report & reproduction case, and to Krzysztof
+  Rusek for the fix.
 * :release:`2.0.0 <2016-04-28>`
 * :release:`1.17.0 <2016-04-28>`
 * :release:`1.16.1 <2016-04-28>`

tasks.py

@@ -2,7 +2,7 @@
 from os.path import join
 from shutil import rmtree, copytree
 
-from invoke import Collection, ctask as task
+from invoke import Collection, task
 from invocations.docs import docs, www, sites
 from invocations.packaging import publish
 

tests/test_transport.py

@@ -828,3 +828,21 @@ def read_message(self):
                           hostkey=public_host_key,
                           username='slowdive',
                           password='pygmalion')
+
+    def test_M_select_after_close(self):
+        """
+        verify that select works when a channel is already closed.
+        """
+        self.setup_test_server()
+        chan = self.tc.open_session()
+        chan.invoke_shell()
+        schan = self.ts.accept(1.0)
+        schan.close()
+
+        # give client a moment to receive close notification
+        time.sleep(0.1)
+
+        r, w, e = select.select([chan], [], [], 0.1)
+        self.assertEqual([chan], r)
+        self.assertEqual([], w)
+        self.assertEqual([], e)