automaton: raise on Windows WAIT_FAILED

scapy/automaton.py

@@ -95,69 +95,76 @@ def select_objects(inputs, remain):
     events_to_inputs = []
     created = []
     results = set()
-    for i in inputs:
-        fno = i.fileno()
-        if fno < 0:
-            # Special case: On Windows, we consider that an object that returns
-            # a negative fileno (impossible), is always readable. This is used
-            # in very few places but important (e.g. PcapReader), where we have
-            # no valid fileno (and will stop on EOFError).
-            results.add(i)
-            remain = 0
-            continue
-        if getattr(i, "__selectable_force_select__", False):
-            # Native socket.socket object. We would normally use select.select.
-            evt = ctypes.windll.ws2_32.WSACreateEvent()
-            created.append(evt)
-            res = ctypes.windll.ws2_32.WSAEventSelect(
-                ctypes.c_void_p(fno),
-                evt,
-                FD_READ
-            )
-            if res == 0:
-                # Was a socket
-                event = evt
+    try:
+        for i in inputs:
+            fno = i.fileno()
+            if fno < 0:
+                # Special case: On Windows, we consider that an object that returns
+                # a negative fileno (impossible), is always readable. This is used
+                # in very few places but important (e.g. PcapReader), where we have
+                # no valid fileno (and will stop on EOFError).
+                results.add(i)
+                remain = 0
+                continue
+            if getattr(i, "__selectable_force_select__", False):
+                # Native socket.socket object. We would normally use select.select.
+                evt = ctypes.windll.ws2_32.WSACreateEvent()
+                created.append(evt)
+                res = ctypes.windll.ws2_32.WSAEventSelect(
+                    ctypes.c_void_p(fno),
+                    evt,
+                    FD_READ
+                )
+                if res == 0:
+                    # Was a socket
+                    event = evt
+                else:
+                    # Fallback to normal event
+                    event = fno
             else:
-                # Fallback to normal event
                 event = fno
-        else:
-            event = fno
-        events.append(event)
-        events_to_inputs.append(i)
-    if events:
-        # 0xFFFFFFFF = INFINITE
-        remainms = int(remain * 1000 if remain is not None else 0xFFFFFFFF)
-        if len(events) == 1:
-            res = ctypes.windll.kernel32.WaitForSingleObject(
-                ctypes.c_void_p(events[0]),
-                remainms
-            )
-        else:
-            # Sadly, the only way to emulate select() is to first check
-            # if any object is available using WaitForMultipleObjects
-            # then poll the others.
-            res = ctypes.windll.kernel32.WaitForMultipleObjects(
-                len(events),
-                (ctypes.c_void_p * len(events))(
-                    *events
-                ),
-                False,
-                remainms
-            )
-        if res != 0xFFFFFFFF and res != 0x00000102:  # Failed or Timeout
-            results.add(events_to_inputs[res])
-            if len(events) > 1:
-                # Now poll the others, if any
-                for i, evt in enumerate(events):
-                    res = ctypes.windll.kernel32.WaitForSingleObject(
-                        ctypes.c_void_p(evt),
-                        0  # poll: don't wait
-                    )
-                    if res == 0:
-                        results.add(events_to_inputs[i])
-    # Cleanup created events, if any
-    for evt in created:
-        ctypes.windll.ws2_32.WSACloseEvent(evt)
+            events.append(event)
+            events_to_inputs.append(i)
+        if events:
+            # 0xFFFFFFFF = INFINITE
+            remainms = int(remain * 1000 if remain is not None else 0xFFFFFFFF)
+            if len(events) == 1:
+                res = ctypes.windll.kernel32.WaitForSingleObject(
+                    ctypes.c_void_p(events[0]),
+                    remainms
+                )
+            else:
+                # Sadly, the only way to emulate select() is to first check
+                # if any object is available using WaitForMultipleObjects
+                # then poll the others.
+                res = ctypes.windll.kernel32.WaitForMultipleObjects(
+                    len(events),
+                    (ctypes.c_void_p * len(events))(
+                        *events
+                    ),
+                    False,
+                    remainms
+                )
+            # ctypes' default signed c_int restype returns WAIT_FAILED as -1.
+            if res == -1 or res == 0xFFFFFFFF:
+                raise ctypes.WinError()
+            if res != 0x00000102:  # Timeout
+                results.add(events_to_inputs[res])
+                if len(events) > 1:
+                    # Now poll the others, if any
+                    for i, evt in enumerate(events):
+                        res = ctypes.windll.kernel32.WaitForSingleObject(
+                            ctypes.c_void_p(evt),
+                            0  # poll: don't wait
+                        )
+                        if res == -1 or res == 0xFFFFFFFF:
+                            raise ctypes.WinError()
+                        if res == 0:
+                            results.add(events_to_inputs[i])
+    finally:
+        # Cleanup created events, if any
+        for evt in created:
+            ctypes.windll.ws2_32.WSACloseEvent(evt)
     return list(results)