We hardcode the path the initrd uses to prepare the final mount point at
so many places, let's also imply it in "systemctl switch-root" if not
specified.
This adds the fallback both to systemctl and to PID 1 (this is because
both to — different – checks on the path).
Normally we queue initrd-switch-root.target/isolate, which pulls in the
service via Wants= in the .target unit file. But if the service is instead
started directly, there may be nothing pulling in the target. Let's make
sure that the reference exists.
The block is reordered and split to have:
1. description + documentation
2. (optionally) conditions
3. all the dependencies
I think it's easier to read the units this way.
Also, the Conflicts+Before is seperated out to separate lines.
The ordering dependency is "fake", because it could just as well be
After=, we are adding it to force ordering wrt. shutdown.target, and
it plays a different role than the other Before=, which are about a
real ordering on boot.
This makes things a bit simpler and the build a bit faster, because we don't
have to rewrite files to do the trivial substitution. @rootbindir@ is always in
our internal $PATH that we use for non-absolute paths, so there should be no
functional change.
This will:
* mount all configured filesystems (typically the rootfs on /sysroot)
* reload the configuration to pick up anything from the mounted fs (typically
/sysroot/etc/fstab)
* mount any newly configured filesystems (typically /usr on /sysroot/usr, if
applicable)
* shut-down and clean-up any daemons running in the initramfs (typically udevd)
* switch-root to /sysroot and start the real init
For an example of what files should be included in an initramfs based on this
see
<https://mailman.archlinux.org/pipermail/arch-projects/2013-February/003628.html>.
Cc: Harald Hoyer <harald.hoyer@gmail.com>
Cc: Dave Reisner <d@falconindy.com>
