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

[Markus Armbruster <armbru@redhat.com>]

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?