unit_file_exists() currently does not follow symlinks, as it is
mainly used to test whether the unit (of any install state)
has been seen under search dirs. However, in ssh-generator
we should search for and honor whatever the distro ships,
which might be an alias or linked externally.
The immediate impulse for this change is the fedora scriptlet which called:
/usr/lib/systemd/systemd-update-helper install-system-units cryptsetup-pre.target cryptsetup.target getty@.service ... system-systemd\x2dcryptsetup.slice system-systemd\x2dveritysetup.slice ...
which called
systemctl preset cryptsetup-pre.target cryptsetup.target getty@.service ... system-systemd\x2dcryptsetup.slice system-systemd\x2dveritysetup.slice ...
which threw an error that system-systemdx2dcryptsetup.slice does not exist
and did nothing at all. (The backslash is consumed by the shell.)
The obvious fix here is to figure out more levels of escaping… But we should
do something more robust in such cases.
If we fail in processing of a single unit, let preset all continue processing
units, report the failure through 'changes'. At the end, return failure. In
general, for operations which operate on a list of units specified by the user,
fail the whole operation if any of the individual operations failed. The only
operation where we don't do this is 'preset-all'.
$ SYSTEMD_LOG_LEVEL=debug build/systemctl --root=/ preset asdf1.servie asdf2.path; echo $?
Cannot find unit asdf1.servie.service.
Cannot find unit asdf2.path.
Failed to preset unit: Unit asdf1.servie.service does not exist
Failed to preset unit: Unit asdf2.path does not exist
1
While at it, fix double logging in the manager: dump_unit_changes() already
logs about errors, so the manager should only log on success.
This partially reverts a4f0e0da35. The
intent was good, we gather the errors, but we have no mechanism to
propagate the result, so the gathered result was ignored. In 'changes'
we can only report errors for specific units. If reading of the
directory fails, we might just as well report the error immediately.
This isn't great, but it's better then ignoring the errors. In practice,
failing halfway in this manner is unlikely, since it'd mean that the fs
is corrupted or something like that. We might as well return immediately
on such catastrophic errors.
In recent Fedora, preset-all fails:
[ 155s] Failed to preset unit: File '/buildroot/etc/systemd/user/dbus.service'
already exists and is a symlink to /usr/lib/systemd/user/dbus-broker.service
[ 155s] ‣ "systemctl --root=/buildroot --global preset-all" returned non-zero exit code 1.
Strictly speaking, this is an error in configuration. The presets specify that
both dbus-broker.service and dbus-daemon.service shall be enabled and they both
claim the 'dbus.service' alias. But this kind of error is very easy to make.
Failing the preset operation is too harsh, since in most cases the system will
work fine without an alias and changes in unrelated components can cause the
conflict.
Let's reuse the same logic that was added in
ad5fdd3912: when enabling the unit through
'preset' or 'preset-all', print the message, but suppress the error. When
enabling through 'enable', fail the operation.
We might be operating with a newer systemctl on an image with older
systemd and thus without an initrd-preset directory. Before
4a8c395167, we would use the system
presets, let's make sure we keep doing that if we're operating on an
image without initrd presets.
Follow up for 4a8c395167.
Currently, when running "systemctl preset-all --root=xxx" in mkosi
to enable/disable units for initrds, the system presets are used.
The problem with this approach is that the system presets are written
for the system, and that is not necessarily ideal for an initrd, but we
still want to use the same packages in the initrd that we install in the
system, so let's introduce a separate directory for initrd presets which
is used to pick up preset files from when we detect that we're configuring
an initrd (by looking for /etc/initrd-release).
We also introduce a systemd preset file for the initrd, which is based on
the system one, except with all the stuff unnecessary for the initrd removed.
Otherwise, the result may point to outside of the root directory.
This also sets CONF_FILES_REGULAR and CONF_FILES_FILTER_MASKED, as the
callers will call fopen() or friends for the result, thus the enumerated
results must be non-empty regular files.
Admittedly, some of our glyphs _are_ special, e.g. "O=" for SPECIAL_GLYPH_TOUCH ;)
But we don't need this in the name. The very long names make some invocations
very wordy, e.g. special_glyph(SPECIAL_GLYPH_SLIGHTLY_UNHAPPY_SMILEY).
Also, I want to add GLYPH_SPACE, which is not special at all.
We so far collected most unexpected errors from install_changes_add()
and propagated them – but for some invocations we forgot to do that. Add
that, and take care we only propagated unexpected errors (i.e. ENOMEM
and such), but treat expected errors as before.
Follow-up for 5163c9b1e5
Currently, install_info_apply() only updates r if it's 0,
meaning that if one of the earlier install_info_symlink_alias/wants()
calls returns > 0, errors generated by later calls will be discarded.
Fix that.
If a symlink is leftover, still allow cleaning it up via 'disable'. This
happens when a unit is stopped and removed, but not disabled, and a reload
has already happened. At that point, cleaning up the old symlinks becomes
impossible through the APIs, and needs to be done manually. Always allow
cleaning up symlinks, if they exist, by only erroring out if there is an
OOM.
Follow-up for f31f10a620
Firstly, if we encounter an error when iterating over the directory, gather
the error but continue. This is unlikely to happen, but if it happens, then
it doesn't seem very useful to break the preset processing at a random
point. If we can't process a unit — too bad, but since we already might
have processed some units earlier, we might as well try to process the
remaining ones.
Secondly, add missing error codes for units that are in a bad state to the
exclusion list. Those, we report them in the changes list, but consider the
whole operation a success. (-ETXTBSY and -ENOLINK were missing.)
Thirdly, add a message generator for -ENOLINK.
Fixes https://github.com/systemd/systemd/issues/21224.
Currently, if a unit file is enabled from outside of the search path,
and that unit has an alias, then the symlink ends up pointing outside of
the search path too. For example:
$ cat /tmp/a.service
[Service]
ExecStart=sleep infinity
[Install]
Alias=b.service
WantedBy=multi-user.target
$ systemctl enable /tmp/a.service
Created symlink /etc/systemd/system/a.service → /tmp/a.service.
Created symlink /etc/systemd/system/b.service → /tmp/a.service.
Created symlink /etc/systemd/system/multi-user.target.wants/a.service → /tmp/a.service.
This then means the alias is treated as a separate unit:
$ systemctl start a.service
$ sudo systemctl status a
● a.service
Loaded: loaded (/etc/systemd/system/a.service; enabled; preset: enabled)
Active: active (running) since Fri 2024-03-15 15:17:49 EDT; 9s ago
Main PID: 769593 (sleep)
Tasks: 1 (limit: 18898)
Memory: 220.0K
CPU: 5ms
CGroup: /system.slice/a.service
└─769593 sleep infinity
Mar 15 15:17:49 six systemd[1]: Started a.service.
$ sudo systemctl status b
○ b.service
Loaded: loaded (/etc/systemd/system/b.service; alias)
Active: inactive (dead)
To fix this, make sure the alias uses a target that is inside the search
path. Since the unit file itself is outside of the search path, a
symlink inside the search path will have been created already. Hence,
just point the alias symlink to that recently created symlink.
On ppc64el with gcc 13.2 on Ubuntu 24.04:
3s In file included from ../src/basic/macro.h:386,
483s from ../src/basic/alloc-util.h:10,
483s from ../src/shared/install.c:12:
483s ../src/shared/install.c: In function ‘install_changes_dump’:
483s ../src/shared/install.c:432:64: error: ‘%s’ directive argument is null [-Werror=format-overflow=]
483s 432 | err = log_error_errno(changes[i].type, "Failed to %s unit, unit %s does not exist.",
483s | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
483s ../src/shared/install.c:432:75: note: format string is defined here
483s 432 | err = log_error_errno(changes[i].type, "Failed to %s unit, unit %s does not exist.",
Mike Yuan
Zbigniew Jędrzejewski-Szmek
Yu Watanabe
Daan De Meyer
Lennart Poettering
Luca Boccassi
Nick Rosbrook