Re: strscpy

Le 29/05/2020 à 20:49, Maxime Villard a écrit :
> Le 29/05/2020 à 20:36, matthew green a écrit :
>>>>> I would want to keep the difference minimal between the two. I think
>>>>> that the
>>>>> version that returns -1 is nice and addresses the concern. What do you
>>>>> think?
>>>>
>>>> Personally I have got no strong opinion. I would change "size > INT_MAX"
>>>> to "size > SSIZE_MAX".
>>>>
>>>> Returning -1 instead of -EINVAL and -E2BIG is good, as there few users
>>>> who check return value at all, and if so, they check whether it is less
>>>> than 0.
>>>
>>> I have updated my patch:
>>>
>>>     https://m00nbsd.net/garbage/libkern/strscpy.diff
>>>
>>> We simply return -1. Will commit soon unless there is valid objection.
>>
>> i strongly object.
>>
>> please don't commit more dual-return value APIs.
>>
>> kre's point about it is 100% valid.  they're extremely
>> dangerous.
> 
> I have still not seen any valid technical reason why they are "dangerous".
> Now they're suddenly "extremely dangerous", but you fail to explain how.
> 
>> i spent a couple of months tracking down a
>> mismatch between linux and netbsd errno values that
>> happens because linux APIs regularly return "-errno",
>> and we (bsd generally, not just netbsd) have avoided
>> that idiom in most places by design.
> 
> You did notice that I am _not_ returning a negative errno, right?
> 
> This is an anecdote about Linux-to-BSD mishaps, caused by Linux using
> negative errnos. I could easily quote you a hundred BSD-to-BSD mishaps
> I've seen in imported subsystems and drivers.
> 
> Maxime

PS: and I will still move forward unless I hear a valid technical
objection.