Merge branch '1.17' into 2.0

5 files changed, 42 insertions, 8 deletions

diff --git a/dev-requirements.txt b/dev-requirements.txt
index 0c1fc020..2547fb5f 100644
--- a/dev-requirements.txt
+++ b/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
diff --git a/paramiko/buffered_pipe.py b/paramiko/buffered_pipe.py
index d5fe164e..605f51e9 100644
--- a/paramiko/buffered_pipe.py
+++ b/paramiko/buffered_pipe.py
@@ -70,11 +70,20 @@ class BufferedPipe (object):
         
         :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):
         """
diff --git a/sites/www/changelog.rst b/sites/www/changelog.rst
index c5aeb48e..df818b47 100644
--- a/sites/www/changelog.rst
+++ b/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>`
diff --git a/tasks.py b/tasks.py
index 9e8c56d2..90ee758c 100644
--- a/tasks.py
+++ b/tasks.py
@@ -2,7 +2,7 @@ from os import mkdir
 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
 
diff --git a/tests/test_transport.py b/tests/test_transport.py
index 5069e5b0..d81ad8f3 100644
--- a/tests/test_transport.py
+++ b/tests/test_transport.py
@@ -828,3 +828,21 @@ class TransportTest(unittest.TestCase):
                           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)