[Rpm-maint] rpm --chroot and glibc/nscd

[Michael Schroeder]

On Tue, May 17, 2011 at 04:27:08PM +0300, Panu Matilainen wrote:
> Did you try talking to glibc developers about this? Just asking so I 
> wont bother them again if they already told you to keep the pieces or 
> something to that effect...

Not really. I was never successful when proposing something to
Ulrich Drepper, so I didn't dare this time ;-)
Also, I needed a fix for the old SUSE versions, so it didn't make
much sense to ask for some new functionality.

But I agree that support in glibc would be much better than this
hack. Note that you have to both delete the ncsd connection and
flush the nss setup.

> >The patch also
> >- fixes the cache usage. lastUnameLen/lastGnameLen were never
> >   set, so the code *always* did a getpwuid/gid call!
> >- renames lastU/GnameLen to lastU/GnameAlloced in
> >   rpmugU/Gname, so that it is consistent with the
> >   rpmugU/Gid function.
> >
> >Even if you do not want the safe_lookup() part, having a
> >rpmugChroot() function that calls endpwent()/endgrent() and
> >drops the local caches if a chroot is done seems like a
> >good idea.
> 
> Hmm, wouldn't it suffice to just store the rpmChrootDone() state in 
> rpmug and flush the caches etc when the chroot_done state has changed 
> between calls?

Yes, that was actually how I coded it earlier. I then simplified
it a bit -- how often is the chroot state changed?

> Other than that, will apply at least the other bits, I'll mull over the 
> safe_lookup() a bit (perhaps a bit academic but it might break if the 
> chrooted version is configured to use something else than files for user 
> information, but then it probably doesn't work now either due to glibc 
> remembering that stuff).

Yes, that's why it is better to tell glibc to re-read the nss
setup. OTOH it probably doesn't make much sense if glibc does
ldap lookups in the chroot or something like that.

Cheers,
  Michael.

-- 
Michael Schroeder                                   mls at suse.de
SUSE LINUX Products GmbH,  GF Jeff Hawn, HRB 16746 AG Nuernberg
main(_){while(_=~getchar())putchar(~_-1/(~(_|32)/13*2-11)*13);}