Make sure optarg is set before calling parse().

iptc/xtables.py

@@ -337,6 +337,9 @@ def _parse(self, module, argv, inv, flags, entry, ptr):
     # Dispatch arguments to the appropriate parse function, based upon the
     # extension's choice of API.
     def parse_target(self, argv, invert, t, fw, ptr):
+        _optarg.value = argv[1]
+        _optind.value = 2
+
         if not t.x6_options or not t.x6_parse: # old API
             self._parse(t, argv, invert, t.tflags, fw, ptr)
             return
@@ -346,9 +349,6 @@ def parse_target(self, argv, invert, t, fw, ptr):
         if not entry:
             raise XTablesError("%s does not know parameter" % (t.name, argv[0]))
 
-        _optarg.value = argv[1]
-        _optind.value = 2
-
         cb = xt_option_call()
         cb.entry = ct.pointer(entry)
         cb.arg      = _optarg
@@ -368,6 +368,9 @@ def parse_target(self, argv, invert, t, fw, ptr):
     # Dispatch arguments to the appropriate parse function, based upon the
     # extension's choice of API.
     def parse_match(self, argv, invert, m, fw, ptr):
+        _optarg.value = argv[1]
+        _optind.value = 2
+
         if not m.x6_options or not m.x6_parse: # old API
             self._parse(m, argv, invert, m.mflags, fw, ptr)
             return
@@ -377,9 +380,6 @@ def parse_match(self, argv, invert, m, fw, ptr):
         if not entry:
             raise XTablesError("%s does not know parameter" % (m.name, argv[0]))
 
-        _optarg.value = argv[1]
-        _optind.value = 2
-
         cb = xt_option_call()
         cb.entry = ct.pointer(entry)
         cb.arg      = _optarg