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

On Thu, Oct 26, 2023 at 01:38:50PM -0400, Steven Rostedt wrote:

On Thu, 26 Oct 2023 10:07:28 -0700
Kees Cook [off-list ref] wrote:

quoted

Solve two ergonomic issues with struct seq_buf:

"ergonomic"? Does it cause carpal tunnel? ;-)

quoted

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