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object: fix OBJ_PROP_LINK_UNREF_ON_RELEASE ambivalence

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A link property can be set during creation, with
object_property_add_link() and later with object_property_set_link().

add_link() doesn't add a reference to the target object, while
set_link() does.

Furthemore, OBJ_PROP_LINK_UNREF_ON_RELEASE flags, set during add_link,
says whether a reference must be released when the property is destroyed.
This can lead to leaks if the property was later set_link(), as the
added reference is never released.

Instead, rename OBJ_PROP_LINK_UNREF_ON_RELEASE to OBJ_PROP_LINK_STRONG
and use that has an indication on how the link handle reference
management in set_link().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-id: 20180531195119.22021-3-marcandre.lureau@redhat.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Marc-André Lureau 2018-05-31 21:51:17 +02:00 • committed by Gerd Hoffmann
parent f3d58385a6
commit 265b578c58
17 changed files with 32 additions and 24 deletions
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12
include/qom/object.h
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@ -1103,6 +1103,11 @@ char *object_property_get_str(Object *obj, const char *name,
* @errp: returns an error if this function fails
*
* Writes an object's canonical path to a property.
*
* If the link property was created with
* <code>OBJ_PROP_LINK_STRONG</code> bit, the old target object is
* unreferenced, and a reference is added to the new target object.
*
*/
void object_property_set_link(Object *obj, Object *value,
const char *name, Error **errp);
@ -1394,7 +1399,7 @@ void object_property_add_child(Object *obj, const char *name,
typedef enum {
/* Unref the link pointer when the property is deleted */
OBJ_PROP_LINK_UNREF_ON_RELEASE = 0x1,
OBJ_PROP_LINK_STRONG = 0x1,
} ObjectPropertyLinkFlags;
/**
@ -1432,8 +1437,9 @@ void object_property_allow_set_link(const Object *, const char *,
* link property. The reference count for <code>*@child</code> is
* managed by the property from after the function returns till the
* property is deleted with object_property_del(). If the
* <code>@flags</code> <code>OBJ_PROP_LINK_UNREF_ON_RELEASE</code> bit is set,
* the reference count is decremented when the property is deleted.
* <code>@flags</code> <code>OBJ_PROP_LINK_STRONG</code> bit is set,
* the reference count is decremented when the property is deleted or
* modified.
*/
void object_property_add_link(Object *obj, const char *name,
const char *type, Object **child,