qom: Fix invalid error check in property_get_str()

When a function returns a null pointer on error and only on error, you
can do

    if (!foo(foos, errp)) {
        ... handle error ...
    }

instead of the more cumbersome

    Error *err = NULL;

    if (!foo(foos, &err)) {
        error_propagate(errp, err);
        ... handle error ...
    }

A StringProperty's getter, however, may return null on success!  We
then fail to call visit_type_str().

Screwed up in 6a146eb, v1.1.

Fails tests/qom-test in my current, heavily hacked QAPI branch.  No
reproducer for master known (but I didn't look hard).

Cc: Anthony Liguori <anthony@codemonkey.ws>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Andreas Färber <afaerber@suse.de>
This commit is contained in:
Markus Armbruster 2015-08-25 20:00:46 +02:00 committed by Andreas Färber
parent 4715d42efe
commit e1c8237df5

View File

@ -1612,12 +1612,16 @@ static void property_get_str(Object *obj, Visitor *v, void *opaque,
{
StringProperty *prop = opaque;
char *value;
Error *err = NULL;
value = prop->get(obj, errp);
if (value) {
visit_type_str(v, &value, name, errp);
g_free(value);
value = prop->get(obj, &err);
if (err) {
error_propagate(errp, err);
return;
}
visit_type_str(v, &value, name, errp);
g_free(value);
}
static void property_set_str(Object *obj, Visitor *v, void *opaque,