qom: Change object_get_canonical_path_component() not to malloc

object_get_canonical_path_component() returns a malloced copy of a
property name on success, null on failure.

19 of its 25 callers immediately free the returned copy.

Change object_get_canonical_path_component() to return the property
name directly.  Since modifying the name would be wrong, adjust the
return type to const char *.

Drop the free from the 19 callers become simpler, add the g_strdup()
to the other six.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200714160202.3121879-4-armbru@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Li Qiang <liq3ea@gmail.com>

2 files changed, 7 insertions, 11 deletions

diff --git a/qom/object.c b/qom/object.c
index 76f5f75239..00fdf89b3b 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -1931,7 +1931,7 @@ object_property_add_const_link(Object *obj, const char *name,
                                 NULL, OBJ_PROP_LINK_DIRECT);
 }
 
-char *object_get_canonical_path_component(const Object *obj)
+const char *object_get_canonical_path_component(const Object *obj)
 {
     ObjectProperty *prop = NULL;
     GHashTableIter iter;
@@ -1947,7 +1947,7 @@ char *object_get_canonical_path_component(const Object *obj)
         }
 
         if (prop->opaque == obj) {
-            return g_strdup(prop->name);
+            return prop->name;
         }
     }
 
@@ -1966,7 +1966,7 @@ char *object_get_canonical_path(const Object *obj)
     }
 
     do {
-        char *component = object_get_canonical_path_component(obj);
+        const char *component = object_get_canonical_path_component(obj);
 
         if (!component) {
             /* A canonical path must be complete, so discard what was
@@ -1978,7 +1978,6 @@ char *object_get_canonical_path(const Object *obj)
 
         newpath = g_strdup_printf("/%s%s", component, path ? path : "");
         g_free(path);
-        g_free(component);
         path = newpath;
         obj = obj->parent;
     } while (obj != root);
diff --git a/qom/qom-hmp-cmds.c b/qom/qom-hmp-cmds.c
index aaacadacca..4032c96089 100644
--- a/qom/qom-hmp-cmds.c
+++ b/qom/qom-hmp-cmds.c
@@ -96,10 +96,8 @@ static void print_qom_composition(Monitor *mon, Object *obj, int indent);
 
 static int qom_composition_compare(const void *a, const void *b, void *ignore)
 {
-    g_autofree char *ac = object_get_canonical_path_component(a);
-    g_autofree char *bc = object_get_canonical_path_component(b);
-
-    return g_strcmp0(ac, bc);
+    return g_strcmp0(object_get_canonical_path_component(a),
+                     object_get_canonical_path_component(b));
 }
 
 static int insert_qom_composition_child(Object *obj, void *opaque)
@@ -112,18 +110,17 @@ static int insert_qom_composition_child(Object *obj, void *opaque)
 
 static void print_qom_composition(Monitor *mon, Object *obj, int indent)
 {
-    char *name;
+    const char *name;
     GQueue children;
     Object *child;
 
     if (obj == object_get_root()) {
-        name = g_strdup("");
+        name = "";
     } else {
         name = object_get_canonical_path_component(obj);
     }
     monitor_printf(mon, "%*s/%s (%s)\n", indent, "", name,
                    object_get_typename(obj));
-    g_free(name);
 
     g_queue_init(&children);
     object_child_foreach(obj, insert_qom_composition_child, &children);