qom: allow creating an alias of a child<> property

Child properties must be unique.  Fix this problem by
turning their aliases into links.

The resolve function that forwards to the target property
does not have any knowledge of the target property's type,
so it works fine.

Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/qom/object.c b/qom/object.c
index 7a892ef4a6..f49335f0cf 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1607,22 +1607,32 @@ void object_property_add_alias(Object *obj, const char *name,
     AliasProperty *prop;
     ObjectProperty *op;
     ObjectProperty *target_prop;
+    gchar *prop_type;
 
     target_prop = object_property_find(target_obj, target_name, errp);
     if (!target_prop) {
         return;
     }
 
+    if (object_property_is_child(target_prop)) {
+        prop_type = g_strdup_printf("link%s",
+                                    target_prop->type + strlen("child"));
+    } else {
+        prop_type = g_strdup(target_prop->type);
+    }
+
     prop = g_malloc(sizeof(*prop));
     prop->target_obj = target_obj;
     prop->target_name = target_name;
 
-    op = object_property_add(obj, name, target_prop->type,
+    op = object_property_add(obj, name, prop_type,
                              property_get_alias,
                              property_set_alias,
                              property_release_alias,
                              prop, errp);
     op->resolve = property_resolve_alias;
+
+    g_free(prop_type);
 }
 
 static void object_instance_init(Object *obj)