Em Mon, 30 Oct 2017 23:18:08 +0100
Daniel Scheller <d.scheller.oss@xxxxxxxxx> escreveu:
> From: Daniel Scheller <d.scheller@xxxxxxx>
>
> Fixes: d73dcf0cdb95 ("media: dvb_frontend: cleanup ioctl handling logic")
>
> The mentioned commit cleaned up the ioctl handling, but caused an issue
> with the DVBv3 when they're not defined in a frontend's fe_ops: When a
> userspace application checks for existence and success of a fe_ops with ie.
>
> if (!ioctl(fd, FE_READ_BER, &val))
>
> this will not report failure anymore since in dvb_frontend_handle_ioctl(),
> err is unitialised and thus zero, and "case FE_READ_BER" (and the
> following) doesn't care about the case that fe_op isn't set by the frontend
> driver. So, success is always reported while the value at the passed ptr
> isn't updated. This breaks userspace applications relying on v3 stats.
>
> Fix this by initialising err to -EOPNOTSUPP like it was before the commit.
> This only affects (and fixes) the DVBv3 stat ioctls, every other handled
> ioctl sets err to a proper return value.
>
> Signed-off-by: Daniel Scheller <d.scheller@xxxxxxx>
> ---
> Discovered and tested with TVHeadend (current GIT master HEAD) which does
> fallback to DVBv3 stats inquiry when v5 is absent.
>
> drivers/media/dvb-core/dvb_frontend.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c
> index daaf969719e4..cc64fa38a1df 100644
> --- a/drivers/media/dvb-core/dvb_frontend.c
> +++ b/drivers/media/dvb-core/dvb_frontend.c
> @@ -2113,6 +2113,8 @@ static int dvb_frontend_handle_ioctl(struct file *file,
>
> dev_dbg(fe->dvb->device, "%s:\n", __func__);
>
> + err = -EOPNOTSUPP;
> +
This patch is incomplete and will cause troubles with DVBv5. The
right fix is:
https://patchwork.linuxtv.org/patch/45277/
Could you please test reply to its tread with a tested-by if it passes
on your tests?
Thanks,
Mauro
