When used in a package installation script, we want to invoke systemd-sysusers
before that package is installed (so it can contain files owned by the newly
created user), so the configuration to use is specified on the command
line. This should be a copy of the configuration that will be installed as
/usr/lib/sysusers.d/package.conf. We still want to obey any overrides in
/etc/sysusers.d or /run/sysusers.d in the usual fashion. Otherwise, we'd get a
different result when systemd-sysusers is run with a copy of the new config on
the command line and when systemd-sysusers is run at boot after package
instalation. In the second case any files in /etc or /run have higher priority,
so the same should happen when the configuration is given on the command line.
More generally, we want the behaviour in this special case to be as close to
the case where the file is finally on disk as possible, so we have to read all
configuration files, since they all might contain overrides and additional
configuration that matters. Even files that have lower priority might specify
additional groups for the user we are creating. Thus, we need to read all
configuration, but insert our new configuration somewhere with the right
priority.
If --target=/path/to/file.conf is given on the command line, we gather the list
of files, and pretend that the command-line config is read from
/path/to/file.conf (doesn't matter if the file on disk actually exists or
not). All package scripts should use this option to obtain consistent and
idempotent behaviour.
The corner case when --target= is specified and there are no positional
arguments is disallowed.
v1:
- version with --config-name=
v2:
- disallow --config-name= and no positional args
v3:
- remove --config-name=
v4:
- add --target= and rework the code completely
v5:
- fix argcounting bug and add example in man page
v6:
- rename --target to --replace
If the configuration is included in a script, this is more convient.
I thought it would be possible to use this for rpm scriptlets with
'%pre -p systemd-sysuser "..."', but apparently there is no way to pass
arguments to the executable ($1 is used for the package installation count).
But this functionality seems generally useful, e.g. for testing and one-off
scripts, so let's keep it.
There's a slight change in behaviour when files are given on the command line:
if we cannot parse them, error out instead of ignoring the failure. When trying
to parse all configuration files, we don't want to fail even if some config
files are broken, but when parsing a list of items specified explicitly, we
should.
v2:
- rename --direct to --inline
This is the first error message when running unprivileged, and the message is
unspecific, so let's at least add some logging at debug level to make this less
confusing.
The function `strv_join_quoted()` is now not used, and has a bug
in the buffer size calculation when the strings needs to escaped,
as reported in #8056.
So, let's remove the function.
Closes#8056.
On Debian/Ubuntu systems the default passwd/group files use a
slightly strange mapping. E.g. in passwd:
```
man:x:6:12::/var/cache/man:/sbin/nologin
```
and in group:
```
disk:x:6:
man:x:12:
```
This is not supported in systemd-sysusers right now because
sysusers will not re-use an existing uid/gid in its normal
mode of operation. Unfortunately this reuse is needed to
replicate the default Debian/Ubuntu users/groups.
This commit enforces reuse when the "uid:gid" syntax is used
to fix this.
I also added a test that replicates the Debian base-passwd
passwd/group file to ensure things are ok.
Technically, `data` is a sequence of bytes without a trailing zero,
so the use of `memcmp` seems to be logical here. Besides, this helps get
around a bug that makes `asan` report the false positive mentioned in
#8052.
Closes#8052.
