Re: [Minios-devel] [UNIKRAFT PATCH] lib/vfscore: sys_ioctl() - Fix build with nolibc

[Costin Lupu <costin.lup@xxxxxxxxx>]

On 9/11/19 6:27 PM, Sharan Santhanam wrote:
> 
> On 9/11/19 3:38 PM, Costin Lupu wrote:
>> Hi Sharan,
>>
>> On 9/11/19 3:56 PM, Sharan Santhanam wrote:
>>> Hello Costin,
>>>
>>> The fix seems fine. Please find the question inline.
>>>
>>> Thanks & Regards
>>>
>>> Sharan
>>>
>>> On 9/11/19 1:56 PM, Costin Lupu wrote:
>>>> Commit 3dcccd04 introduced handling of FIOCLEX and FIONCLEX requests.
>>>> However,
>>>> these flags are not defined in nolibc.
>>>>
>>>> Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
>>>> ---
>>>>    lib/nolibc/include/sys/ioctl.h | 0
>>> Why do we introduce a empty file? In newlib we introduces a header
>>> imported from musl.
>>>
>> I didn't get that completely, does it build on your side? Do you get any
>> errors/warnings?
> No, but I guess with a review process you do clarify why you made
> certain choices.
>>
>>> Why don't we use the same file here?
>> This is an open question. The thing is that newlib itself seems to be a
>> poor choice if we do copy so much code from musl. Now getting back to
>> nolibc, if we do add more and more code from musl then we can simply get
>> rid of it too and use musl instead. In conclusion, I fail to see why we
>> should copy code to nolibc instead using musl directly.
> But in this case we are introducing the FIONCLEX and FIOCLEX within the
> core Unikraft and it is expected to work with nolibc. Instead of adding
> #ifdef it would be better to make it feature complete.

Now why would you say it is expected to work with nolibc? The two flags
are actually related with close-on-exec logic. Why would any app running
on top of Unikraft and which would not use a libc implementation need to
call exec() since this is not possible? Besides this, there is no exec()
function in nolibc.

Cheers,
Costin

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