Re: [PATCH 4/4] libvduse: Check the return value of some ioctls

[Yongji Xie]

On Wed, Jun 29, 2022 at 5:41 PM Markus Armbruster <armbru@redhat.com> wrote:
>
> Xie Yongji <xieyongji@bytedance.com> writes:
>
> > Coverity pointed out (CID 1490222, 1490227) that we called
> > ioctl somewhere without checking the return value. This
> > patch fixes these issues.
> >
> > Fixes: Coverity CID 1490222, 1490227
> > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > ---
> >  subprojects/libvduse/libvduse.c | 10 ++++++++--
> >  1 file changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/subprojects/libvduse/libvduse.c 
> > b/subprojects/libvduse/libvduse.c
> > index 1a5981445c..bf7302c60a 100644
> > --- a/subprojects/libvduse/libvduse.c
> > +++ b/subprojects/libvduse/libvduse.c
> > @@ -947,7 +947,10 @@ static void vduse_queue_disable(VduseVirtq *vq)
> >
> >      eventfd.index = vq->index;
> >      eventfd.fd = VDUSE_EVENTFD_DEASSIGN;
> > -    ioctl(dev->fd, VDUSE_VQ_SETUP_KICKFD, &eventfd);
> > +    if (ioctl(dev->fd, VDUSE_VQ_SETUP_KICKFD, &eventfd)) {
> > +        fprintf(stderr, "Failed to disable eventfd for vq[%d]: %s\n",
> > +                vq->index, strerror(errno));
> > +    }
> >      close(vq->fd);
> >
> >      assert(vq->inuse == 0);
> > @@ -1337,7 +1340,10 @@ VduseDev *vduse_dev_create(const char *name, 
> > uint32_t device_id,
> >
> >      return dev;
> >  err:
> > -    ioctl(ctrl_fd, VDUSE_DESTROY_DEV, name);
> > +    if (ioctl(ctrl_fd, VDUSE_DESTROY_DEV, name)) {
> > +        fprintf(stderr, "Failed to destroy vduse device %s: %s\n",
> > +                name, strerror(errno));
> > +    }
> >  err_dev:
> >      close(ctrl_fd);
> >  err_ctrl:
>
> Both errors are during cleanup that can't fail.  The program continues
> as if they didn't happen.  Does the user need to know?
>

So I printed some error messages. I didn't find any other good way to
notify the users.

Thanks,
Yongji