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.
It turns out most possible symlinks are invalid, because the type has to match,
and template units can only be linked to template units.
I'm not sure if the existing code made the same checks consistently. At least
I don't see the same rules expressed in a single place.
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.
This file was testing a mix of functions from src/core/load-fragment.c and some
from src/shared/install.c. Let's name it more appropriately. I want to add
tests for the new unit-file.c too.
So far, we'd use hashmap_free_free to free both keys and values along with
the hashmap. I think it's better to make this more encapsulated: in this variant
the way contents are freed can be decided when the hashmap is created, and
users of the hashmap can always use hashmap_free.
This could already be done by calling unit_name_is_*(), but if we don't know
if the argument is a valid unit name, it is more convenient to have a single
function which returns the type or possibly an error if the unit name is not
valid.
The values in the enum are sorted "by length". Not really important, but it
seems more natural to me.
Similar variables had differing names: unit, path, unit_path. We also
have file system paths in surrounding code. Let's make this easier for
the reader and use "dbus_path" consistently.
It had two users, but it is just a very thin wrapper around
unit_file_find_dropin_paths(), so using it seems more complicated than directly
invoking unit_file_find_dropin_paths() twice.
The description of Alias= wasn't incorrect, but it sounded like Alias= creates
a different type of dependency, while it's just a glorified way to create
symlinks. Also recommend 'preset' in addition to 'enable'.
Describe .wants/.requires dirs as equals, without implying that the [Install]
section can only be used for .wants.
The text was partially out of date (systemd-networkd.service now creates as
alias in /etc, not /usr/lib, let's just not say anything about the full path).
The commit
"util: Do not clear parent mount flags when setting up namespaces"
introduced a statvfs call read the flags of the original mount
and have them applied to the bind mount.
This has two problems:
(1) The mount flags returned by statvfs(2) do not match the flags
accepted by mount(2). For example, the value 4096 means ST_RELATIME
when returned by statvfs(2), but means MS_BIND when passed to mount(2).
(2) A call to statvfs blocks indefinitely when ran against a disconnected
network drive ( https://github.com/systemd/systemd/issues/12667 ).
We already use libmount to parse `/proc/self/mountinfo` but did not use the
mount flag information from there. This patch changes that to use the mount
flags parsed by libmount instead of calling statvfs. Only if getting the
flags through libmount fails we call statvfs.
Fixes https://github.com/systemd/systemd/issues/12667
without using -type f, the logs print an error such as:
E: E: modprobe: FATAL: Module asymmetric_keys not found in directory /lib/modules/4.15.0-54-generic
while this doesn't appear to cause problems, it can be extremely
distracting when trying to debug real failures.
Almost all tests were manually mounting/unmounting $TESTDIR/root
from the loopback image; this moves all that into test-functions
so the test setup functions are simplier.
Also add test_setup_cleanup() function, to cleanup what is mounted
by create_empty_image_rootdir()
