Marc-André Lureau <marcandre.lur...@redhat.com> writes:
> Since commit ad739706bbadee49, user_creatable_add_type() expects to be
> given a qdict. However, if object-add is called without props, you reach
> the assert: "qemu/qom/object_interfaces.c:115: user_creatable_add_type:
> Assertion `qdict' failed.", because the qdict isn't created in this
> case (it's optional).
>
> Furthermore, qmp_input_visitor_new() is not meant to be called without a
> dict, and a further commit will assert in this situation.
>
> If none given, create an empty qdict in qmp to avoid the
> user_creatable_add_type() assert(qdict).
>
> Signed-off-by: Marc-André Lureau <marcandre.lur...@redhat.com>
> ---
> qmp.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/qmp.c b/qmp.c
> index 6733463..8078038 100644
> --- a/qmp.c
> +++ b/qmp.c
> @@ -665,7 +665,7 @@ void qmp_add_client(const char *protocol, const char
> *fdname,
> void qmp_object_add(const char *type, const char *id,
> bool has_props, QObject *props, Error **errp)
> {
> - const QDict *pdict = NULL;
> + QDict *pdict;
> Visitor *v;
> Object *obj;
>
> @@ -675,14 +675,19 @@ void qmp_object_add(const char *type, const char *id,
> error_setg(errp, QERR_INVALID_PARAMETER_TYPE, "props", "dict");
> return;
> }
> + } else {
> + pdict = qdict_new();
> }
>
> - v = qmp_input_visitor_new(props, true);
> + v = qmp_input_visitor_new(QOBJECT(pdict), true);
> obj = user_creatable_add_type(type, id, pdict, v, errp);
> visit_free(v);
> if (obj) {
> object_unref(obj);
> }
> + if (!props) {
> + qobject_decref(QOBJECT(pdict));
> + }
> }
>
> void qmp_object_del(const char *id, Error **errp)
The reference counting here is needlessly complex.
Case props != NULL:
* The caller holds a reference to props
* pdict = qobject_to_qdict(props) is a weak reference (not counted)
Case props == NULL:
* pdict = qdict_new() is a counted reference
* When it goes out of scope, we need to decrement the reference count.
I recommend to avoid the dual nature of pdict, by converting the weak
reference into a strong one, then decrement the reference count
unconditionally:
if (props) {
pdict = qobject_to_qdict(props);
if (!pdict) {
error_setg(errp, QERR_INVALID_PARAMETER_TYPE, "props", "dict");
return;
}
QINCREF(pdict);
} else {
pdict = qdict_new();
}
v = qmp_input_visitor_new(QOBJECT(pdict), true);
obj = user_creatable_add_type(type, id, pdict, v, errp);
visit_free(v);
if (obj) {
object_unref(obj);
}
QDECREF(pdict);
