[PATCH] rfkill: return ENOTTY on invalid ioctl

[PATCH] rfkill: return ENOTTY on invalid ioctl

[Thomas Weißschuh]

For unknown ioctls the correct error is
ENOTTY "Inappropriate ioctl for device".

ENOSYS as returned before should only be used to indicate that a syscall
is not available at all.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 net/rfkill/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/rfkill/core.c b/net/rfkill/core.c
index 14cc8fe8584b..c3feb4f49d09 100644
--- a/net/rfkill/core.c
+++ b/net/rfkill/core.c
@@ -1351,11 +1351,11 @@ static long rfkill_fop_ioctl(struct file *file, unsigned int cmd,
 			     unsigned long arg)
 {
 	struct rfkill_data *data = file->private_data;
-	int ret = -ENOSYS;
+	int ret = -ENOTTY;
 	u32 size;
 
 	if (_IOC_TYPE(cmd) != RFKILL_IOC_MAGIC)
-		return -ENOSYS;
+		return -ENOTTY;
 
 	mutex_lock(&data->mtx);
 	switch (_IOC_NR(cmd)) {

---
base-commit: 7d461b291e65938f15f56fe58da2303b07578a76
change-id: 20231101-rfkill-ioctl-enosys-00a2bb0a4ab1

Best regards,
-- 
Thomas Weißschuh <linux@weissschuh.net>

Re: [PATCH] rfkill: return ENOTTY on invalid ioctl

[Przemek Kitszel]

On 11/1/23 20:41, Thomas Weißschuh wrote:
> For unknown ioctls the correct error is
> ENOTTY "Inappropriate ioctl for device".

For sure!

I would like to learn more of why this is not an UAPI breaking change?

> 
> ENOSYS as returned before should only be used to indicate that a syscall
> is not available at all.
> 
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> ---
>   net/rfkill/core.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/rfkill/core.c b/net/rfkill/core.c
> index 14cc8fe8584b..c3feb4f49d09 100644
> --- a/net/rfkill/core.c
> +++ b/net/rfkill/core.c
> @@ -1351,11 +1351,11 @@ static long rfkill_fop_ioctl(struct file *file, unsigned int cmd,
>   			     unsigned long arg)
>   {
>   	struct rfkill_data *data = file->private_data;
> -	int ret = -ENOSYS;
> +	int ret = -ENOTTY;
>   	u32 size;
>   
>   	if (_IOC_TYPE(cmd) != RFKILL_IOC_MAGIC)
> -		return -ENOSYS;
> +		return -ENOTTY;
>   
>   	mutex_lock(&data->mtx);
>   	switch (_IOC_NR(cmd)) {
> 
> ---
> base-commit: 7d461b291e65938f15f56fe58da2303b07578a76
> change-id: 20231101-rfkill-ioctl-enosys-00a2bb0a4ab1
> 
> Best regards,

Re: [PATCH] rfkill: return ENOTTY on invalid ioctl

[Thomas Weißschuh]

Hi!

On 2023-11-02 09:57:45+0100, Przemek Kitszel wrote:
> On 11/1/23 20:41, Thomas Weißschuh wrote:
> > For unknown ioctls the correct error is
> > ENOTTY "Inappropriate ioctl for device".
> 
> For sure!
> 
> I would like to learn more of why this is not an UAPI breaking change?

"break" would mean that some user application worked correctly before
but does not do so anymore with this change.

This seems highly unlikely and I was not able to find such an
application via Debian code search.

In general I did *not* mark this change for stable so if some
application would indeed break it gets detected before the patch hits
a release.

> > 
> > ENOSYS as returned before should only be used to indicate that a syscall
> > is not available at all.
> > 
> > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> > ---
> >   net/rfkill/core.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/net/rfkill/core.c b/net/rfkill/core.c
> > index 14cc8fe8584b..c3feb4f49d09 100644
> > --- a/net/rfkill/core.c
> > +++ b/net/rfkill/core.c
> > @@ -1351,11 +1351,11 @@ static long rfkill_fop_ioctl(struct file *file, unsigned int cmd,
> >   			     unsigned long arg)
> >   {
> >   	struct rfkill_data *data = file->private_data;
> > -	int ret = -ENOSYS;
> > +	int ret = -ENOTTY;
> >   	u32 size;
> >   	if (_IOC_TYPE(cmd) != RFKILL_IOC_MAGIC)
> > -		return -ENOSYS;
> > +		return -ENOTTY;
> >   	mutex_lock(&data->mtx);
> >   	switch (_IOC_NR(cmd)) {
> > 
> > ---
> > base-commit: 7d461b291e65938f15f56fe58da2303b07578a76
> > change-id: 20231101-rfkill-ioctl-enosys-00a2bb0a4ab1
> > 
> > Best regards,
> 

Re: [PATCH] rfkill: return ENOTTY on invalid ioctl

[Przemek Kitszel]

On 11/2/23 20:14, Thomas Weißschuh wrote:
> Hi!
> 
> On 2023-11-02 09:57:45+0100, Przemek Kitszel wrote:
>> On 11/1/23 20:41, Thomas Weißschuh wrote:
>>> For unknown ioctls the correct error is
>>> ENOTTY "Inappropriate ioctl for device".
>>
>> For sure!
>>
>> I would like to learn more of why this is not an UAPI breaking change?
> 
> "break" would mean that some user application worked correctly before
> but does not do so anymore with this change.
> 
> This seems highly unlikely and I was not able to find such an
> application via Debian code search.
> 
> In general I did *not* mark this change for stable so if some
> application would indeed break it gets detected before the patch hits
> a release.
> 
>>>
>>> ENOSYS as returned before should only be used to indicate that a syscall
>>> is not available at all.
>>>
>>> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
>>> ---
>>>    net/rfkill/core.c | 4 ++--
>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/net/rfkill/core.c b/net/rfkill/core.c
>>> index 14cc8fe8584b..c3feb4f49d09 100644
>>> --- a/net/rfkill/core.c
>>> +++ b/net/rfkill/core.c
>>> @@ -1351,11 +1351,11 @@ static long rfkill_fop_ioctl(struct file *file, unsigned int cmd,
>>>    			     unsigned long arg)
>>>    {
>>>    	struct rfkill_data *data = file->private_data;
>>> -	int ret = -ENOSYS;
>>> +	int ret = -ENOTTY;
>>>    	u32 size;
>>>    	if (_IOC_TYPE(cmd) != RFKILL_IOC_MAGIC)
>>> -		return -ENOSYS;
>>> +		return -ENOTTY;
>>>    	mutex_lock(&data->mtx);
>>>    	switch (_IOC_NR(cmd)) {
>>>
>>> ---
>>> base-commit: 7d461b291e65938f15f56fe58da2303b07578a76
>>> change-id: 20231101-rfkill-ioctl-enosys-00a2bb0a4ab1
>>>
>>> Best regards,
>>

Thanks!

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>