Re: [PATCH v2 09/15] softmmu/qdev-monitor: add error handling in qdev_set_id

[Kevin Wolf <kwolf@redhat.com>]

Am 13.10.2021 um 23:37 hat Eric Blake geschrieben:
> On Wed, Oct 13, 2021 at 03:10:38PM +0200, Damien Hedde wrote:
> > > > @@ -691,7 +703,13 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
> > > >           }
> > > >       }
> > > > -    qdev_set_id(dev, g_strdup(qemu_opts_id(opts)));
> > > > +    /*
> > > > +     * set dev's parent and register its id.
> > > > +     * If it fails it means the id is already taken.
> > > > +     */
> > > > +    if (!qdev_set_id(dev, g_strdup(qemu_opts_id(opts)), errp)) {
> > > > +        goto err_del_dev;
> > > 
> > > ...nor on this, which means the g_strdup() leaks on failure.
> > > 
> > 
> > Since we strdup the id just before calling qdev_set_id.
> > Maybe we should do the the strdup in qdev_set_id (and free things on error
> > there too). It seems simplier than freeing things on the callee side just in
> > case of an error.
> 
> Indeed.  If we expected qdev_set_id() to be passed something that it
> can later free, we would have used 'char *'; but because we used
> 'const char *' for that parameter, it really does make more sense for
> the callers to pass in any string and for qdev_set_id() to do the
> necessary strdup()ing, as well as clean up on error.

Since this seems to be the only thing in the series that needs to be
addressed, I'll do the minimal fix while applying (adding g_free() to
the error path in qemu_opts_id()) and then we can clean up on top.

Kevin