Do not send TERM signal to a process that has already been waited on

re6st/tunnel.py

@@ -86,8 +86,8 @@ class Connection(object):
     def close(self):
         try:
             self.process.stop()
-        except (AttributeError, OSError):
-            pass # we already polled an exited process
+        except AttributeError:
+            pass
 
     def refresh(self):
         # Check that the connection is alive

re6st/utils.py

@@ -156,10 +156,11 @@ class Popen(subprocess.Popen):
             self.returncode = -1
 
     def stop(self):
-        if self.pid:
+        if self.pid and self.returncode is None:
             self.terminate()
             t = threading.Timer(5, self.kill)
             t.start()
+            # PY3: use waitid(WNOWAIT) and call self.poll() after t.cancel()
             r = self.wait()
             t.cancel()
             return r