libubus: fix ubus_invoke() to return err in case ubus_start_request() fails

Seems the UBUS_MAX_MSGLEN is ignored by ubus_invoke(),
and then segfault happens.

This issue is present before this set of patches.

diff --git a/libubus-req.c b/libubus-req.c
index f24f033..8475dc9 100644 (file)
--- a/libubus-req.c
+++ b/libubus-req.c
@@ -224,8 +224,12 @@ int ubus_invoke(struct ubus_context *ctx, uint32_t obj, const char *method,
                int timeout)
 {
        struct ubus_request req;
+       int rc;
+
+       rc = ubus_invoke_async(ctx, obj, method, msg, &req);
+       if (rc)
+               return rc;
 
-       ubus_invoke_async(ctx, obj, method, msg, &req);
        req.data_cb = cb;
        req.priv = priv;
        return ubus_complete_request(ctx, &req, timeout);