Re: [PATCH can-utils v2 1/3] headers: use include/linux only for Linux kernel headers

[Oliver Hartkopp <socketcan@hartkopp.net>]

On 13.01.2014 08:20, Uwe Kleine-König wrote:
> Hello Oliver,
> 
> On Mon, Jan 13, 2014 at 07:23:55AM +0100, Oliver Hartkopp wrote:
>> On 12.01.2014 22:24, Uwe Kleine-König wrote:
>>
>>>  - use __kernel_sa_family_t instead of sa_family_t which requires
>>>    <linux/socket.h from Linux 3.1 or later. Unfortunately this makes
>>>    can-utils FTBFS on e.g. Debian squeeze. If this is an issue this
>>>    could be fixed by adding something like:
>>
>> This was exactly the idea to have a separate set of include files to make sure
>> the 'newest and greatest' tools can be build even on 2.6.24 environments where
>> there was no SocketCAN in mainline Linux.
> Hmm, the newest and greatest tools are unusable if your kernel doesn't
> also include the newest and greatest SocketCAN stuff.

Features that are not available in the kernel come back with an error.
But there's no reason not to have the latest can-utils with bug fixes and
functional enhancements for older kernels, right?

> And then it is
> easy to also have updated kernel headers, isn't it? Well, anyhow I just
> found a system here at pengutronix with old enough kernel headers, so I
> will do a fix.

ok. tnx.

>  
>> And e.g. this
>>
>>>  #include <linux/can.h>
>>> -#include <linux/can/isotp.h>
>>> +#include "isotp.h"
>>>  #include <linux/if_tun.h>
>>
>> should be avoided too.
> Why?

When isotp hits the kernel, there's no need to adapt all userland programs.

I don't think the current idea was that bad.
AFAIK the iproute2 package has a similar approach and contains always updated
kernel headers to be able to build even on older systems.


Best regards,
Oliver