capture OSErrors while receiving data (hardbyte#87)

umlaeute · hardbyte · commit 192d730ee58f · 2016-10-19T14:46:00.000+11:00
Handle OSErrors while receiving data off socketcan native. Both sock.recv() and select.select(sock) throw errors when the device to which the socket is bound goes down. This makes the notifier thread survive such a condition (and bail out on the log) Closes: hardbyte#86
diff --git a/can/interfaces/socketcan_native.py b/can/interfaces/socketcan_native.py
@@ -278,6 +278,10 @@ def capturePacket(sock):
     except socket.timeout:
         log.debug('Captured no data, socket read timed out.')
         return None
+    except OSError:
+        # something bad happened (e.g. the interface went down)
+        log.exception("Captured no data.")
+        return None
 
     can_id, can_dlc, data = dissect_can_frame(cf)
     log.debug('Received: can_id=%x, can_dlc=%x, data=%s', can_id, can_dlc, data)
@@ -335,11 +339,17 @@ def shutdown(self):
         self.socket.close()
 
     def recv(self, timeout=None):
+        data_ready = True
+        try:
+            if timeout is not None:
+                data_ready = len(select.select([self.socket], [], [], timeout)[0]) > 0
+        except OSError:
+            # something bad happened (e.g. the interface went down)
+            log.exception("Error while waiting for timeout")
+            return None
 
-        if timeout is None or len(select.select([self.socket],
-                                                [], [], timeout)[0]) > 0:
+        if data_ready:
             packet = capturePacket(self.socket)
-
             # The capturePacket function can return None if
             # self.socket.settimeout has been called.
             if packet is None:
