This allows to limit units to machines that run on a certain firmware
type. For device tree defined machines checking against the machine's
compatible is also possible.
See https://bugzilla.redhat.com/show_bug.cgi?id=1893417 for the back story:
the fallback hostname matters a lot in certain environments. Right now the only
way to configure the fallback hostname is by recompiling systemd, which is
obviously problematic in case when the fallback hostname shall differ between
different editions of the same distro that share a single compiled rpm.
By making this overridable through an envvar, we're providing an escape hatch
without making this a top-level api. Later on a way to set this through
os-release is added, but I think the approach with the variable is still
useful. It it very convenient for testing, or to override settings only in a
particular service, etc.
This updates the docs about using fdisk/gdisk to make partitions with the right
partition type UUID as defined in the discoverable partitions spec.
Improve wording/grammar/formatting, and reflect that gdisk supports this as
well nowadays; see https://www.rodsbooks.com/gdisk/revisions.html
The wiki was slightly stale, and almost all the information there
was already present in the man page. I moved the remaing part (discussion)
into the man page and adjusted all links to point to the man page instead.
daemon(7) has a some examples of packaging scriptlets… I don't think it fits
there very well. Most likely they should be moved to systemd.preset(5) or maybe
even removed, but I'm leaving that for later.
Very old versions of meson did not include the subdirectory name in the
target name, so we started adding various "top-level" custom targets in
subdirectories. This was nice because the main meson.build file wasn't
as cluttered. But then meson started including the subdir name in the
target name. So let's move the definition to the root so we can have all
targets named uniformly.
While it's perfectly possible today to completely rely on mkosi for
building and testing systemd, to get code completion and other IDE
niceties to work properly, it's still necessary to build systemd
locally.
Recently, mkosi gained the ability to allow external programs to
communicate with the build script. We can use this feature to run
the clangd language server in the mkosi build image via a custom
build script to provide IDE features in editors without requiring
developers to build systemd on the host or install any of systemd's
build dependencies locally.
This commit adds the necessary information on how to set this up
to HACKING.md.
