python: Fix errors for Database.lookup()

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

src/python/database.c

@@ -199,18 +199,21 @@ static PyObject* Database_lookup(DatabaseObject* self, PyObject* args) {
 		loc_network_unref(network);
 
 		return obj;
+	}
 
 	// Nothing found
-	} else if (r == 1) {
+	if (!errno)
 		Py_RETURN_NONE;
 
-	// Invalid input
-	} else if (r == -EINVAL) {
-		PyErr_Format(PyExc_ValueError, "Invalid IP address: %s", address);
-		return NULL;
+	// Handle any errors
+	switch (errno) {
+		case EINVAL:
+			PyErr_Format(PyExc_ValueError, "Invalid IP address: %s", address);
+
+		default:
+			PyErr_SetFromErrno(PyExc_OSError);
 	}
 
-	// Unexpected error
 	return NULL;
 }