Dacav.org, screw up & restore

This post marks the beginning of a new era!  OK, maybe
that's a bit of an overstatement.  But yeah, I've
finally registered a domain for this machine.

Obviously I had to modify the configuration of certain
parts of the system in order to reflect the
registration.  This boiled down to updating the host
name in the provisioning system.

Regarding said provisioning system: it is a very simple
tool I've constructed from scratch.  The basic
principle is the same as ansible (that is,
idem-powerful actions), although it does not rely on
Python, or any other dependency besides what is already
available on a vanilla target operating system
(FreeBSD).  It simply leverages SSH and the POSIX
shell.

As any not-invented-here-syndrome byproducts, it has
some obvious downsides.  Most notably: (1) it is
tailored for one target system, and (2) it is not as
tested as popular products such as Ansible.

The second point is interesting in that it might be
seen as a disservice, but it helps a lot in gaining
experience.  Obviously I don't care much if the site is
down for a while: my salary and life do NOT depend on
it.  I'm here to maximize the FUN.

Speaking of screwing up, since the remote file copying
mechanism relies on tar(1), the reconfiguration turned
out to mess with file permissions, which is why the
system stopped to work for every non-root user.

I found some inspiration on this thread[1].  I've used
mtree(1) against BSD.root.dist[2] to find and repair
the base system path that I damaged.  Some of the
broken permissions turned out to be under /usr/local/,
for which I had no mtree(1) specification.

Everything was correctly restored by:

- Carefully removing /usr/local and /var/db/pkg

- Re-running the setup script

- Exercising the back-up restoration

The next thing is to put toghether a mtree(1)
specification for the parts touched by the setup
scripts.

.[1] https://forums.freebsd.org/threads/users-not-in-wheel-group-cannot-log-in-anymore.62491/
.[2] https://cgit.freebsd.org/src/plain/etc/mtree/BSD.root.dist