libubus: preserve the received message buffer for incoming invoke calls

Set ctx->msgbuf.data to NULL during the call. If ctx->msgbuf is needed
during the call, a new buffer will be allocated. If not,
ctx->msgbuf.data is restored to the previous value afterwards

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

diff --git a/libubus-obj.c b/libubus-obj.c
index ef104620d3b9edba3d4be56f85b7b6d9e7797fe9..8bc83dc62cfd163f32702ebc13605d9067400259 100644 (file)
--- a/libubus-obj.c
+++ b/libubus-obj.c
@@ -99,6 +99,7 @@ void __hidden ubus_process_obj_msg(struct ubus_context *ctx, struct ubus_msghdr_
        struct blob_attr **attrbuf;
        struct ubus_object *obj;
        uint32_t objid;
+       void *prev_data = NULL;
 
        attrbuf = ubus_parse_msg(buf->data);
        if (!attrbuf[UBUS_ATTR_OBJID])
@@ -120,7 +121,20 @@ void __hidden ubus_process_obj_msg(struct ubus_context *ctx, struct ubus_msghdr_
        default:
                return;
        }
+
+       if (buf == &ctx->msgbuf) {
+               prev_data = buf->data;
+               buf->data = NULL;
+       }
+
        cb(ctx, hdr, obj, attrbuf);
+
+       if (prev_data) {
+               if (buf->data)
+                       free(prev_data);
+               else
+                       buf->data = prev_data;
+       }
 }
 
 static void ubus_add_object_cb(struct ubus_request *req, int type, struct blob_attr *msg)