[Piuparts-devel] Bug#1018893: support for unshare in some form

[Helmut Grohne]

Hi Johannes,

On Mon, Sep 05, 2022 at 07:52:13AM +0200, Johannes Schauer Marin Rodrigues wrote:
> I just uploaded mmdebstrap 1.2.0 which adds a few more --skip options. The ones
> that might be useful here are:
> 
>  - --skip=chroot/mount      -- don't mount anything
>  - --skip=chroot/mount/proc -- only don't mount /proc
>  - --skip=chroot/mount/sys  -- only don't mount /sys
> 
> Maybe this makes implementing this easier?

While that may make the combination simpler, the extra copy involved
here is making things inefficient. Why would piuparts need two temporary
chroots? It should just be using the one mmdebstrap prepared and be
happy with that. So I do think we need a new piuparts option that
explains how --existing-chroot should work:
 * Copy the chroot as a template.
 * Actually use it directly.

While we often want the former, in this case, we want the latter.
Without an extra option, piuparts will be unable to tell those two cases
apart and always use it as a template.

Helmut