Re: backward compatibility: how far can it reasonably go?

[Brad Spencer <brad%anduin.eldar.org@localhost>]

Jason Thorpe <thorpej%me.com@localhost> writes:

>> On Dec 8, 2021, at 10:52 AM, Greg A. Woods <woods%planix.ca@localhost> wrote:
>> 
>> That's one bullet I've dodged entirely already since my oldest systems
>> are running netbsd-5 stable.  (Though in theory isn't there supposed to
>> be COMPAT support for SA?)
>
> int
> compat_60_sys_sa_register(lwp_t *l,
>         const struct compat_60_sys_sa_register_args *uap,
>         register_t *retval)
> {
>         return sys_nosys(l, uap, retval);
> }
>
> SA is one of those things that's REALLY hard to provide compatibility for.
>
> -- thorpej


Ya, that...  I remember a diff that is probably sitting in a mailing
list message somewhere that provided an emulation I think at the lib
layer for this.  However, in the case I mentioned, the lack of support
was not a show stopper.  It really was the only thing that caused any
problems at all.  Even a 7.x kernel, as an initial test, booted with a
4.x userland didn't really have any real trouble in that it ran all of
the /etc/rc stuff mostly just fine and I could log in.  I would suspect
that going from 5.x forward would not be just too much of a problem.



-- 
Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org