Getting a custom package into a new system early in the install process

[Ross Boylan <rossboylan@stanfordalumni.org>]

I have a customized package, adduser, that I want to get into new VM's
early in the wheezy installation process.  In particular, it must
happen before installing the "debian basic system tools" (DBST
hereafter) recommended when the installer gets to task selection.  The
modified adduser tweaks the UID/GID assignments and the DBST
installation creates some of those incorrectly.


The rest of this message gives some approaches I've thought of and
problems with each.

My first thought was that I could point the installer at the host
machine and have a thin cache there that would use my adduser if asked
for that, and otherwise forward requests to somewhere else. But the
closest thing I've found is that I could set up an alternate
repository with the package.(1)  Unfortunately, debootstrap only can
use one repository
(https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=762222).

At task selection the regular apt mechanisms may be in use, in which
case adding repositories to sources.list would work.  How could I
intervene to modify the sources.list in time?

Alternately I could take an installer disk image and modify it. I've
been using netinst, which I don't think has many (any?) regular debs
on it, as opposed to udebs.  Perhaps I should try some fatter image
and tweak the archive.

It's also possible that if I skipped even the base packages at the
task step things would be OK.  I know that if I debootstrap a system
and avoid installing extras the result is OK (i.e., not IDs allocated
in a way that conflicts with my desired scheme). But it's not clear
how I could install those packages later; the list of tasks under
aptitude does not include a "base packages" task.  Maybe it's all
"essential" packages?

Thanks for any help.

Ross Boylan

(1) And presenting a merged view of a synthetic repository with one
package replaced would be tricky, because various master files would
need to be different from upstream to avoid security problems with the
modified package.