qom: Add object_get_container()

Add a helper to fetch a root container (under object_get_root()).  Sanity
check on the type of the object.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-ID: <20241121192202.4155849-12-peterx@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

qom/object.c

@@ -1751,6 +1751,16 @@ static Object *object_root_initialize(void)
     return root;
 }
 
+Object *object_get_container(const char *name)
+{
+    Object *container;
+
+    container = object_resolve_path_component(object_get_root(), name);
+    assert(object_dynamic_cast(container, TYPE_CONTAINER));
+
+    return container;
+}
+
 Object *object_get_root(void)
 {
     static Object *root;