Re: [gentoo-dev] Requirements for UID/GID management

[Patrick McLean <chutzpah@gentoo.org>]

On Fri, 27 Jan 2017 14:53:18 -0500
Rich Freeman <rich0@gentoo.org> wrote:

> On Fri, Jan 27, 2017 at 2:35 PM, Michael Orlitzky <mjo@gentoo.org>
> wrote:
> > On 01/27/2017 01:52 PM, Rich Freeman wrote:  
> >>
> >> This doesn't really seem like a problem though.  Just have a table
> >> somewhere (wiki?) to track who is using what UID/GID and encode
> >> those defaults into the ebuild that creates those users.
> >>  
> >
> > It should be possible to have two different users with the same UID
> > in the tree, just like we can have two different packages that
> > install the same file. Eventually somebody will notice a file
> > collision, and then we add a blocker per usual.
> >  
> 
> I'm not saying we can't have random assignment for things where it
> doesn't matter, or fall back to random assignment, but it seems rather
> silly to go to all the trouble to have blockers when it would be just
> as easy to not have a conflict in the first place.  Now, if we have
> some longstanding issue from the past that might be another matter,
> but what's wrong with just picking an unused ID (again, for stuff that
> needs it)?
> 
> Telling users that they can't have postfix and apache on the same box
> because nobody can be bothered to pick IDs that don't collide seems
> like an arbitrary imposition.  Sometimes upstream creates conflicts
> that are just hard to work around (same SONAME, different ABI or even
> API, and so on).  And if we were talking about some binary-only
> upstream package that relies on hardcoded UIDs I guess blockers might
> be our only option, and users will just have to be happy that we're
> able to support it at all.  However, we shouldn't be the ones creating
> these kinds of conflicts.
> 

I don't think we need to have stable UIDs/GIDs in the "normal" case of
standalone users with a single Gentoo system at home. The people who
need predictable UIDs/GIDs are the "enterprise" users or the home users
who use things such as NFS. I work for a company that uses Gentoo, we
have a bunch of workarounds to make sure that UIDs and GIDs are
stable. To make something to solve our problem (and I suspect everyone
else who cares about this), it would be sufficient to have a mechanism
to override the default random assignment with a fixed UID/GID.
Possibly some file in /etc/portage or in the profile (or both) that
allows one to configure what UID/GID a user will get when the user is
being created. One advantage of this is that user.eclass could be
modified to support it, so we don't have to wait for a new EAPI before
taking advantage of it.