The `set-root-password` command sets up an alternate mount namespace
with a writable `/etc` directory and then runs `passwd` in it. This
allows `passwd` to create its lock files and backup files, without
requiring that the real `/etc` to be mutable. After `passwd` finishes
and has updated its private copy of `/etc/shadow`, the script rewrites
the real one with its contents.
In order for users to be able to log in locally or via SSH without an
authorized key, they will need to have passwords set in `/etc/shadow`.
We do not really want to make all of `/etc` writable, so we will store
the actual `shadow` file on the persistent data volume, in a separate
Btrfs subvolume, and then bind-mount it at `/etc/shadow`.
While this makes `/etc/shadow` mutable, it does not actually let the
`passwd` program modify it. This is because `passwd` creates lock files
and backup files in `/etc`. We will ultimately need a wrapper to
"trick" `passwd` into modifying `/etc/shadow`, without making the whole
`/etc` directory mutable.
Apparently, BusyBox's `cp` does NOT copy SELinux contexts when the `-a`
argument is specified. This differs from GNU coreutils's `cp`, and
explains why the files copied from the rootfs image to the persistent
storage volume were not being labelled correctly. The `-c` argument is
required.
Now that files are labelled correctly when they are copied, the step to
run `restorecon` is no longer necessary.
In effort to support different builds of Aimee OS using the same
scripts, without necessarily having to fork this repository, the build
system now supports a `CONFIGDIR` setting. When this variable is set,
files defining the target environment, such as the lists of packages to
install, the kernel configuration, the Portage configuration, etc. are
found in the path it specifes.
The reference build, for the Home Assistant Yellow board, is configured
in the `yellow` directory. To build it, run:
```sh
CONFIGDIR=yellow ./vm-build.sh
```
Dustin