Also, even if login.defs are not present, don't start allocating at 1, but at
SYSTEM_UID_MIN.
Fixes#9769.
The test is adjusted. Actually, it was busted before, because sysusers would
never use SYSTEM_GID_MIN, so if SYSTEM_GID_MIN was different than
SYSTEM_UID_MIN, the tests would fail. On all "normal" systems the two are
equal, so we didn't notice. Since sysusers now always uses the minimum of the
two, we only need to substitute one value.
We don't (and shouldn't I think) look at them when determining the type of the
user, but they should be used during user/group allocation. (For example, an
admin may specify SYS_UID_MIN==200 to allow statically numbered users that are
shared with other systems in the range 1–199.)
It makes little sense to make the boundary between systemd and user guids
configurable. Nevertheless, a completely fixed compile-time define is not
enough in two scenarios:
- the systemd_uid_max boundary has moved over time. The default used to be
500 for a long time. Systems which are upgraded over time might have users
in the wrong range, but changing existing systems is complicated and
expensive (offline disks, backups, remote systems, read-only media, etc.)
- systems are used in a heterogenous enviornment, where some vendors pick
one value and others another.
So let's make this boundary overridable using /etc/login.defs.
Fixes#3855, #10184.
User records have the realname/gecos fields, groups never had that, but
it would really be useful to have it, hence let's add it with similar
semantics.
We enforce the same syntax as for GECOS, since it's better to start with
strict rules and losen them later instead of the opposite.
We'd like to use it for FIDO2 tokens too, and the concept is entirely
generic, hence let's just reuse the field, but rename it. Read the old
name for compatibility, and treat the old name and the new name as
identical for most purposes.
We make this entirely independent of the regular discard field, i.e. the
one that controls discard behaviour when the home directory is online.
Not all combinations make a ridiculous amount of sense, but most do.
Specifically:
online-discard = yes, offline-discard = yes
→ Discard when activating explicitly, and during runtime using
the "discard" mount option, and discard explicitly when logging
out again.
online-discard = no, offline-discard = yes
→ The new default: when logging in allocate the full backing
store, and use no discard while active. When loging out discard
everything. This provides nice behaviour: we take minimal storage
when offline but provide allocation guarantees while online.
online-discard = no, offline-discard = no
→ Never, ever discard, always operate with fully allocated
backing store. The extra safe mode.
Zbigniew Jędrzejewski-Szmek