Don't try to show top level drop-in for non-existent units or when trying to
instantiate non-instantiated units:
$ systemctl cat nonexistent@.service
Assertion 'name' failed at src/shared/dropin.c:143, function unit_file_find_dirs(). Aborting.
$ systemctl cat systemd-journald@.service
Assertion 'name' failed at src/shared/dropin.c:143, function unit_file_find_dirs(). Aborting.
Discussed in #13743, the -.service semantic conflicts with the
existing root mount and slice names, making this feature not
uniformly extensible to all types. Change the name to be
<type>.d instead.
Updating to this format also extends the top-level dropin to
unit types.
This reworks how we load units from disk. Instead of chasing symlinks every
time we are asked to load a unit by name, we slurp all symlinks from disk
and build two hashmaps:
1. from unit name to either alias target, or fragment on disk
(if an alias, we put just the target name in the hashmap, if a fragment
we put an absolute path, so we can distinguish both).
2. from a unit name to all aliases
Reading all this data can be pretty costly (40 ms) on my machine, so we keep it
around for reuse.
The advantage is that we can reliably know what all the aliases of a given unit
are. This means we can reliably load dropins under all names. This fixes#11972.
I adjusted the tests to pass. I don't think the behaviour makes much sense,
even if we ignore the issue with "lazy loading" of aliases. E.g. in the
last section, the fact that dropins for yup@.service and yup@3.service are
not loaded seems to be a plain old bug.
We had all kinds of indentation: 2 sp, 3 sp, 4 sp, 8 sp, and mixed.
4 sp was the most common, in particular the majority of scripts under test/
used that. Let's standarize on 4 sp, because many commandlines are long and
there's a lot of nesting, and with 8sp indentation less stuff fits. 4 sp
also seems to be the default indentation, so this will make it less likely
that people will mess up if they don't load the editor config. (I think people
often use vi, and vi has no support to load project-wide configuration
automatically. We distribute a .vimrc file, but it is not loaded by default,
and even the instructions in it seem to discourage its use for security
reasons.)
Also remove the few vim config lines that were left. We should either have them
on all files, or none.
Also remove some strange stuff like '#!/bin/env bash', yikes.
[zj: tests assertions adjusted to the different logic in which masking
of a dependency through one name, does not forbid the dependency
being added through another name.]
