On 13. Aug 2025, at 13:42, Petr Pavlu wrote:
> On 8/13/25 11:33 AM, Thorsten Blum wrote:
>> On 13. Aug 2025, at 10:59, Petr Pavlu wrote:
>>> Since the code already calculated the length of val and that it fits
>>> into kps->string, is there any advantage (or disadvantage) to using
>>> strscpy() over memcpy()?
>>
>> strscpy() guarantees that the destination buffer 'kps->string' is always
>> NUL-terminated, even if the source 'val' is not. memcpy() just copies
>> the bytes as they are.
>>
>> If it were guaranteed that 'val' is always NUL-terminated, memcpy()
>> would be fine too, but since param_set_copystring() is exported, we
>> probably can't make that assumption.
>
> The function param_set_copystring() checks using
> 'strnlen(val, kps->maxlen) == kps->maxlen' if val contains NUL in the
> first kps->maxlen bytes. It can use memcpy() instead of strscpy() to
> avoid repeating this work.
I see, and yes
memcpy(kps->string, val, len + 1);
would then be slightly more efficient because strscpy() would just
recompute the length before calling memcpy() internally.
I'll submit a v2.
Thanks,
Thorsten
