For units which are aliases of other units, reporting preset status as
"enabled" is rather misleading. For example, dbus.service is an alias of
dbus-broker.service. In list-unit-files we'd show both as "enabled". In
particular, systemctl preset ignores aliases, so showing any preset status at
all is always going to be misleading. Let's introduce a new state "alias" and
use that for all aliases.
I was trying to avoid adding a new state, to keep compatibility with previous
behaviour, but for alias unit files it simply doesn't seem very useful to show
any of the existing states. It seems that the clearly showing that those are
aliases for other units will be easiest to understand for users.
When doing list-unit-files with --root, we would re-read the preset
list for every unit. This uses a cache to only do it once. The time
for list-unit-files goes down by about ~30%.
unit_file_query_preset() is also called from src/core/. This patch does not
touch that path, since the saving there are smaller, since preset status is
only read on demand over dbus, and caching would be more complicated.
If we have a template unit template@.service, it should be allowed to specify a
dependency on a unit without an instance, bar@.service. When the unit is created,
the instance will be propagated into the target, so template@inst.service will
depend on bar@inst.service.
This commit changes unit_dependency_name_compatible(), which makes the manager
accept links like that, and unit_file_verify_alias(), so that the installation
function will agree to create a symlink like that, and finally the tests are
adjusted to pass.
It might be needed to follow symlinks more deeply when we're looking for
enablement symlinks pointing to the removed service.
Let's consider the case where service 'old' is being renamed 'new' (will happen
most likely during package upgrade). Before the service is going to be renamed,
there's the following enablement symlink:
/etc/systemd/system/multi-user.target.wants/old.service -> /usr/lib/systemd/system/old.service
In order to rename 'old' into 'new' and transparently restart the service, the
old name is still provided as a 'static' alias for the new service. This should
also help keeping backward compatibilities since the old name might still be
embedded in unit files, scripts, generators and such.
Hence after the package is upgraded, the following symlinks including the
enablement symlink are present:
/usr/lib/systemd/system/old.service -> new.service
/etc/systemd/system/multi-user.target.wants/old.service -> /usr/lib/systemd/system/old.service
If later the user decides to disable the service, we should figure out that the
enablement symlink (which still has the old name) is actually referring to 'new'
(indirectly) even if it points to the alias.
This mostly reuses existing checkers used by pid1, so handling of aliases
should be consistent. Hopefully, with the test it'll be clearer what it
happening.
Support for .wants/.requires "aliases" is restored. Those are still used in the
wild quite a bit, so we need to support them.
See https://github.com/systemd/systemd/pull/13119 for a discussion of aliases
with an instance that point to a different template: this is allowed.
It turns out that this is not necessary. When we try to resolve alias@inst, we
first check alias@inst, and if that is not found, fall back to alias@. Since we
already created a symlink for alias@, we will find that and the result will be
the same.
Ideally, we would want to report this over back over dbus. But that is pretty hard,
because the unitfile parsing logic doesn't provide any feedback.
systemd-analyze verify also doesn't notice the issue, because it doesn't look
at the [Install] section at all. Let's print a message in the logs at least.
As in the previous commit, ignoring unkown sections means users may be confused
easily. It is better to warn about misspellt section names.
In this case, we are using a separate item table, so we'd ignore all those
sections anyway, so we could list them with out the minus prefixes and the
effect would be the same. But I think it's clearer to prefix them.
It is currently possible to override the DefaultInstance via drop-ins but
not remove it completely. Allow to do that by specifying an empty
DefaultInstance=
prefix_root() is equivalent to path_join() in almost all ways, hence
let's remove it.
There are subtle differences though: prefix_root() will try shorten
multiple "/" before and after the prefix. path_join() doesn't do that.
This means prefix_root() might return a string shorter than both its
inputs combined, while path_join() never does that. I like the
path_join() semantics better, hence I think dropping prefix_root() is
totally OK. In the end the strings generated by both functon should
always be identical in terms of path_equal() if not streq().
This leaves prefix_roota() in place. Ideally we'd have path_joina(), but
I don't think we can reasonably implement that as a macro. or maybe we
can? (if so, sounds like something for a later PR)
Also add in a few missing OOM checks
Since switching to extract_first_word with no flags for parsing
unit names in 4c9565eea5, escape
characters will be stripped from escaped unit names such as
"mnt-persistent\x2dvolume.mount" resulting in the unit not being
configured as defined. Preserve escape characters again for
compatibility with existing preset definitions.
Coverity says:
> Pointer to local outside scope (RETURN_LOCAL)9.
> use_invalid: Using dirs, which points to an out-of-scope temporary variable of type char const *[5].
And indeed, the switch statement forms a scope. Let's use an if to
avoid creating a scope.
This has been irritating me for quite a while: let's prefix these enum
values with a common prefix, like we do for almost all other enums.
No change in behaviour, just some renaming.
In #10583, a unit file lives in ~/.config/systemd/user, and
'systemctl --runtime --user mask' is used to create a symlink in /run.
This symlink has lower priority than the config file, so
'systemctl --user' will happily load the unit file, and does't care about
the symlink at all.
But when asked if the unit is enabled, we'd look for all symlinks, find the
symlink in the runtime directory, and report that the unit is runtime-enabled.
In this particular case the fact that the symlink points at /dev/null, creates
additional confusion, but it doesn't really matter: *any* symlink (or regular
file) that is lower in the priority order is "covered" by the unit fragment,
and should be ignored.
Fixes#10583.
The name argument in UnitFileInstallInfo (i->name) should always be a unit
file name, so the conditional always takes the 'else' branch.
The only call chain that links to find_symlinks_fd() is unit_file_lookup_state
→ find_symlinks_in_scope → find_symlinks → find_symlinks_fd. But
unit_file_lookup_state calls unit_name_is_valid(name), and then name is used
to construct the UnitFileInstallInfo object in install_info_discover, which just
uses the name it was given.
fdopen doesn't accept "e", it's ignored. Let's not mislead people into
believing that it actually sets O_CLOEXEC.
From `man 3 fdopen`:
> e (since glibc 2.7):
> Open the file with the O_CLOEXEC flag. See open(2) for more information. This flag is ignored for fdopen()
As mentioned by @jlebon in #11131.
Zbigniew Jędrzejewski-Szmek