Re: Status of revivesa

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Sat, Sep 27, 2008 at 02:13:47PM +0200, Quentin Garnier wrote:
> > [...]
> > My "perfect world" solution would be to make the sysenter-compatible 
> > reshuffling an option and make COMPAT_30_PTHREAD or some such another 
> > option, and make the two incompatible. That way an admin can clearly 
> > select which way to go. If either were a default, I'd make the sysenter 
> > one default. :-)
> 
> I see two issues with that (though I'd really like to use that
> solution):
> 
>   - there may be 3rd party application that play the same naughty games
>     as the old libpthread, e.g. by storing a ucontext at some point and
>     re-using it later.  I think of interpreted languages that can be
>     compiled for faster execution.  COMPAT_30_PTHREAD would introduce a
>     very weird failure case.
> 
>   - if we ever decide to make a libci686 and load it through ld.so.conf
>     games, COMPAT_30_NETBSD will become a real burden.

This second case can be easily handled: add a sysctl to see if it's a
COMPAT_30_NETBSD kernel and don't load libci686 in this case.

> 
> The first point is not so bad;  I don't even have any evidence such a
> bad application exists (but wandering around pkgsrc you see scary stuff
> though).  As for the second one, it won't apply to 5.0 anyway, so we're
> safe for a while, and we might have a way out later (for instance, if we
> are to ever bump libc, we could bury SA again).

It would also be an issue only if you want to mix 3.0 and 4.0 userlands,
as I see it.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--