Re: [PATCH man 1/1] TIOCLINUX.2const: Document TIOCL_SETSEL selection modes

["Günther Noack" <gnoack3000@gmail.com>]

Hi!

Thanks for the review!

On Sun, Feb 23, 2025 at 08:35:16AM -0800, Jared Finder wrote:
> On 2025-02-23 01:13, Günther Noack wrote:
> > diff --git a/man/man2const/TIOCLINUX.2const
> > b/man/man2const/TIOCLINUX.2const
> > index c0acdd0ea..27758584e 100644
> > --- a/man/man2const/TIOCLINUX.2const
> > +++ b/man/man2const/TIOCLINUX.2const
> > @@ -65,11 +65,49 @@ are the ending
> >  column and row.
> >  (Upper left corner is row=column=1.)
> >  .I sel_mode
> > -is 0 for character-by-character selection,
> > -1 for word-by-word selection,
> > -or 2 for line-by-line selection.
> > -The indicated screen characters are highlighted and saved
> > -in a kernel buffer.
> > +may be one of the following operations:
> > +.RS
> > +.TP
> > +.B TIOCL_SELCHAR
> > +Select character-by-character.
> > +The indicated screen characters are highlighted
> > +and saved in a kernel buffer.
> > +.TP
> > +.B TIOCL_SELWORD
> > +Select word-by-word.
> > +The indicated screen characters are highlighted
> > +and saved in a kernel buffer.
> > +.TP
> > +.B TIOCL_SELLINE
> > +Select line-by-line.
> > +The indicated screen characters are highlighted
> > +and saved in a kernel buffer.
> > +.TP
> > +.B TIOCL_SELPOINTER
> > +Show the pointer at position
> > +.RI ( xe ", " ye ).
> > +.TP
> 
> Wouldn't it be appropriate to call out here that this specific code is not
> intended to be protected by CAP_SYS_ADMIN?

Yes, it would, and that's the intention and what this change is
preparing for.  This commit describes the "selection modes" (without
touching on the CAP_SYS_ADMIN topic) and a follow-up commit should
move the CAP_SYS_ADMIN remark into the sections for the individual
selection modes.

I intentionally postponed the CAP_SYS_ADMIN part of the change until
the time when the semantics are finalized in the kernel, because I did
not want to risk calling the slightly broken intermediate logic to
anyone's attention (where TIOCL_SELMOUSEREPORT requires CAP_SYS_ADMIN,
but only as long as one of the lower four bits of the sel_mode are
set) - that behavior was unintentional and I don't want to promote
that further than necessary. ;-)

So yes, I'll send another small patch once we have a fix on the kernel
side which is merged.

–Günther