Re: kernfs: Prefer strscpy over strlcpy calls

From: Azeem Shaikh
Date: Wed May 10 2023 - 16:48:42 EST

> Absolutely not.
> This makes the whole exercise pointless.
> The reason to use strscpy() is to *avoid* doing the strlen() on the
> source, and limit things to the limited size.
> If you need to do the strlen(), then use strlcpy(). It's a broken
> interface, but creating this kind of horror wrapper that does the same
> thing as strlcpy() is worse than just using the regular version.
> So the strscpy() conversion should *only* be done if the caller
> doesn't care about the difference in return values (or done *together*
> with changing the caller to use the nicer strscpy() return value).
> It's also worth noting that 'strscpy()' not only returns a negative
> error value when the string doesn't fit - it will also possibly do the
> copy one word at a time, and may write extra zeroes at the end of the
> destination (all within the given size, of course).
> So strscpy() is _different_ from strlcpy(), and the conversion should
> not be done unless those differences are ok.

Thanks Linus, that helps clarify a lot. I traced the usage of these
functions across the kernel and plan to do direct replacement only
where it's safe (see thread here:
Let me know if that works for you.