On 02/09/18 12:46, Sakari Ailus wrote:
> Hi Hans,
>
> On Thu, Feb 08, 2018 at 09:36:44AM +0100, Hans Verkuil wrote:
>> If the subdev did not define any controls, then return -ENOTTY if
>> userspace attempts to call these ioctls.
>>
>> The control framework functions will return -EINVAL, not -ENOTTY if
>> vfh->ctrl_handler is NULL.
>>
>> Several of these framework functions are also called directly from
>> drivers, so I don't want to change the error code there.
>>
>> Found with vimc and v4l2-compliance.
>>
>> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
>
> Thanks for the patch.
>
> If the handler is NULL, can there be support for the IOCTL at all? I.e.
> should the missing handler as such result in returning -ENOTTY from these
> functions instead of -EINVAL?
I didn't dare change the control framework. Some of these v4l2_... functions
are called by drivers and I didn't want to analyze them all. If these
functions were only called by v4l2-ioctl.c and v4l2-subdev.c, then I'd have
changed it in v4l2-ctrls.c, but that's not the case.
It would be a useful project to replace all calls from drivers to these
functions (they really shouldn't be used by drivers), but that is out-of-scope
of this patch.
Regards,
Hans
>
>> ---
>> drivers/media/v4l2-core/v4l2-subdev.c | 16 ++++++++++++++++
>> 1 file changed, 16 insertions(+)
>>
>> diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
>> index 43fefa73e0a3..be7a19272614 100644
>> --- a/drivers/media/v4l2-core/v4l2-subdev.c
>> +++ b/drivers/media/v4l2-core/v4l2-subdev.c
>> @@ -187,27 +187,43 @@ static long subdev_do_ioctl(struct file *file, unsigned int cmd, void *arg)
>>
>> switch (cmd) {
>> case VIDIOC_QUERYCTRL:
>> + if (!vfh->ctrl_handler)
>> + return -ENOTTY;
>> return v4l2_queryctrl(vfh->ctrl_handler, arg);
>>
>> case VIDIOC_QUERY_EXT_CTRL:
>> + if (!vfh->ctrl_handler)
>> + return -ENOTTY;
>> return v4l2_query_ext_ctrl(vfh->ctrl_handler, arg);
>>
>> case VIDIOC_QUERYMENU:
>> + if (!vfh->ctrl_handler)
>> + return -ENOTTY;
>> return v4l2_querymenu(vfh->ctrl_handler, arg);
>>
>> case VIDIOC_G_CTRL:
>> + if (!vfh->ctrl_handler)
>> + return -ENOTTY;
>> return v4l2_g_ctrl(vfh->ctrl_handler, arg);
>>
>> case VIDIOC_S_CTRL:
>> + if (!vfh->ctrl_handler)
>> + return -ENOTTY;
>> return v4l2_s_ctrl(vfh, vfh->ctrl_handler, arg);
>>
>> case VIDIOC_G_EXT_CTRLS:
>> + if (!vfh->ctrl_handler)
>> + return -ENOTTY;
>> return v4l2_g_ext_ctrls(vfh->ctrl_handler, arg);
>>
>> case VIDIOC_S_EXT_CTRLS:
>> + if (!vfh->ctrl_handler)
>> + return -ENOTTY;
>> return v4l2_s_ext_ctrls(vfh, vfh->ctrl_handler, arg);
>>
>> case VIDIOC_TRY_EXT_CTRLS:
>> + if (!vfh->ctrl_handler)
>> + return -ENOTTY;
>> return v4l2_try_ext_ctrls(vfh->ctrl_handler, arg);
>>
>> case VIDIOC_DQEVENT:
>
