Re: [PATCH] seq_buf: Introduce DECLARE_SEQ_BUF and seq_buf_cstr()

[Kees Cook <keescook@chromium.org>]

On Thu, Oct 26, 2023 at 01:38:50PM -0400, Steven Rostedt wrote:
> On Thu, 26 Oct 2023 10:07:28 -0700
> Kees Cook <keescook@chromium.org> wrote:
> 
> > Solve two ergonomic issues with struct seq_buf:
> 
> "ergonomic"? Does it cause carpal tunnel? ;-)
> 
> > 
> > 1) Too much boilerplate is required to initialize:
> > 
> > 	struct seq_buf s;
> > 	char buf[32];
> > 
> > 	seq_buf_init(s, buf, sizeof(buf));
> > 
> > Instead, we can build this directly on the stack. Provide
> > DECLARE_SEQ_BUF() macro to do this:
> > 
> > 	DECLARE_SEQ_BUF(s, 32);
> > 
> > 2) %NUL termination is fragile and requires 2 steps to get a valid
> >    C String (and is a layering violation exposing the "internals" of
> >    seq_buf):
> > 
> > 	seq_buf_terminate(s);
> > 	do_something(s->buffer);
> > 
> > Instead, we can just return s->buffer direction after terminating it
> > in refactored seq_buf_terminate(), now known as seq_buf_cstr():
> > 
> > 	do_soemthing(seq_buf_cstr(s));
> 
> Do we really need to call it _cstr? Why not just have seq_buf_str() ?
> 
> I mean, this is C, do we need to state that in the name too?

I'm fine either way. I did that just to make the distinction between our
length-managed string of characters interface (seq_buf), and the
%NUL-terminated string of characters (traditionally called "C String" in
other languages). And it was still shorter than "seq_buf_terminate(s);
s->buffer" ;)

> BTW, I'm perfectly fine with this change, just the naming I have issues
> with.

Cool; thanks for looking at it!

-- 
Kees Cook