Re: [TRIVIAL] kstrdup

From: Linus Torvalds (torvalds@transmeta.com)
Date: Fri Apr 18 2003 - 13:00:02 EST


On Fri, 18 Apr 2003, Jeff Garzik wrote:
> Linus Torvalds wrote:
> > On Fri, 18 Apr 2003, Jeff Garzik wrote:
> >
> >>You should save the strlen result to a temp var, and then s/strcpy/memcpy/
> >
> > No, you should just not do this. I don't see the point.
>
> strcpy has a test for each byte of its contents, and memcpy doesn't.
> Why search 's' for NULL twice?

No, my point is that kstrdup() _itself_ just shouldn't be done. I don't
see it as being worthy of kernel support. Most of the kernel string data
structures are NOT random zero-ended strings anyway: they are either
strictly limited in some ways ("ends in '\0', but limited to PATH_MAX), or
they are explicitly sized ("struct qstr").

I don't much personally like C strings. Explicit lengths tend to have a
lot of advantages, and while a lot of the standard C infrastructure is for
zero-ended strings, they do end up being even worse in the kernel than in
user space (think buffer overflows and limited allocations in general).

                        Linus

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