Re: Have RESOLVE_* flags superseded AT_* flags for new syscalls?

Christian Brauner
2020-03-02T12:55:38Z

On Mon, Mar 02, 2020 at 01:42:50PM +0100, Florian Weimer wrote:
> * Christian Brauner:
>
> > One difference to openat() is that openat2() doesn't silently ignore
> > unknown flags. But I'm not sure that would matter for iplementing
> > openat() via openat2() since there are no flags that openat() knows about
> > that openat2() doesn't know about afaict. So the only risks would be
> > programs that accidently have a bit set that isn't used yet.
>
> Will there be any new flags for openat in the future? If not, we can
> just use a constant mask in an openat2-based implementation of openat.

From past experiences with other syscalls I would expect that any new
features would only be available through openat2().
The way I see it in general is that a revised version of a syscall
basically deprecates the old syscall _wrt to new features_, i.e. new
features will only be available through the revised version unless there
are very strong reasons to also allow it in the old version (security
bug or whatever).
(But I don't want to be presumptuous here and pretend I can make any
definiteve statement. Ultimately it's up to the community, I guess. :))

Christian