Shouldn't gerror_to_dbus_error_message check for both DBUS_GERROR and DBUS_GERROR_REMOTE_EXCEPTION?

[Marcel Tünnissen]

Hi,

I am looking at a crash that occurs sometimes in our code.
It is caused by a call to dbus_message_new_error from
gerror_to_dbus_error_message

In the call the second parameter error_name becomes NULL.

This is obtained through a call to dbus_g_error_get_name
Apparently the function requires both DBUS_GERROR and
DBUS_GERROR_REMOTE_EXCEPTION.
As a reference:
/**
 * dbus_g_error_get_name:
 * @error: the #GError given from the remote method
 * @name: the D-BUS error name
 * @msg: the D-BUS error detailed message
 *
 * This function may only be invoked on a #GError returned from an
 * invocation of a remote method, e.g. via dbus_g_proxy_end_call.
 * Moreover, you must ensure that the error's domain is #DBUS_GERROR,
 * and the code is #DBUS_GERROR_REMOTE_EXCEPTION.
 *
 * Returns: the D-BUS name for a remote exception.
 */
const char *
dbus_g_error_get_name (GError *error)
{
  g_return_val_if_fail (error != NULL, NULL);
  g_return_val_if_fail (error->domain == DBUS_GERROR, NULL);
  g_return_val_if_fail (error->code == DBUS_GERROR_REMOTE_EXCEPTION, NULL);

  return error->message + strlen (error->message) + 1;
}

However the calling function only checks for DBUS_GERROR.
The call to dbus_g_error_get_name from
gerror_to_dbus_error_message
looks like:

DBusMessage *
gerror_to_dbus_error_message (const DBusGObjectInfo *object_info,
			      DBusMessage     *message,
			      GError          *error)
{
  DBusMessage *reply;

  if (!error)
    {
      char *error_msg;

      error_msg = g_strdup_printf ("Method invoked for %s returned FALSE
but did not set error", dbus_message_get_member (message));
      reply = dbus_message_new_error (message,
"org.freedesktop.DBus.GLib.ErrorError", error_msg);
      g_free (error_msg);
    }
  else
    {
      if (error->domain == DBUS_GERROR)
       reply = dbus_message_new_error (message,
                                   dbus_g_error_get_name (error),
                                   error->message);
      else
       {
         char *error_name;
         error_name = gerror_domaincode_to_dbus_error_name (object_info,

dbus_message_get_interface (message),
                                                      error->domain,
error->code);
         reply = dbus_message_new_error (message, error_name,
error->message);
         g_free (error_name);
       }
    }
  return reply;
}

It seems to me that the single check for error->domain == DBUS_GERROR
isn't sufficient.

Should this check for error->code == DBUS_GERROR_REMOTE_EXCEPTION as well?
So that gerror_domaincode_to_dbus_error_name is called to retrieve the
error_name?

Best Regards
Marcel Tünnissen


-- 
Marcel Tünnissen,
Axis Communications AB
Emdalavägen 14, SE-223 69 LUND, SWEDEN
Phone: +46 (0)46 272 2448
       +46 (0)729 890 369
Email: marcel.tunnissen at axis.com,
WWW: http://www.axis.com