Re: [gentoo-dev] Managing etc/* in an embbeded system

[Jason Zaman]

On Wed, Jul 22, 2015 at 01:20:10PM +0000, Joakim Tjernlund wrote:
> On Wed, 2015-07-22 at 14:30 +0200, Michał Górny wrote:
> >
> > Joakim Tjernlund <joakim.tjernlund@×××××××××.se> napisał:
> >
> > > We got an embedded gentoo system where we need to manage many conf
> > > files under /etc that we have
> > > modified and should be under our control when an SW upgrade is
> > > performed.
> > >
> > > Cloning every ebuild where we have modified its conf file(s) under /etc
> > > feels awkward so
> > > I am looking for some other way to do this automatically during SW
> > > upgrade and I figured
> > > this can not be an unique problem for us, so I wonder how other people
> > > have solved this problem?
> > > Our customers will not use emerge directly and we will provide binary
> > > pkgs.
> > >
> > > Any ideas welcome :)
> > >
> > > Jocke
> >
> > Maybe post-phase hooks would help you. Not around a PC right now but I think they're described in portage.5.
> > Long story short, you create per-package env files in /etc/portage/env (you can pin them generically or to a
> > specific version, or package spec via package.env) and declare post_src_install() where you add your custom
> > config files atop the package.
> >
>
> hmm, that sounds interesting but I don't quite get what to do, you think I should copy over /etc/inittab after
> it has been installed by sys-apps/sysvinit with my own version(which is stored where?)
>
> This gave me an idea though:
> In /etc/portage/env/install-mask.conf I add
>   INSTALL_MASK="${INSTALL_MASK} /etc/inittab /etc/xxx"
> then in /etc/portage/package.env/install-mask
>   sys-apps/sysvinit install-mask.conf
>   sys-apps/xxx install-mask.conf
>   ...
> (Can I do this from my own custom profile instead? how?)
>
> This should prevent sys-apps/sysvinit to install conf files I want to manage, right?
>
> Then I create my own new ebuild holding all config files I have changed myself.

Or you can put a script in /etc/portage/hooks/install/, it will get run
after src_install() during generation of VDB and all that, you could
probably move everything from /etc/ to /etc-orig/ then all packages will
be have things set there, then put your own files in /etc and you can
always refer to /etc-orig/ or even use overlayfs or something to mount
your files on top so they cover the package ones.

-- Jason