Create /etc/subuid and /etc/subguid ranges based on (uid+1) * 100_000

[ermo]

Currently, the existing qol-assist implementation will give all users on a system get the same subuid and subgid ranges:

$ cat /etc/subuid
ermo:1000000:65536
lfs:1000000:65536
root:1000000:65536

$ cat /etc/subgid
ermo:1000000:65536
lfs:1000000:65536
root:1000000:65536

According to this page, user name spaces create mapping tables that look like this:

Host UID	UserNS UID
1000	0
1_000_000	1
1_000_001	2
...	...
1_065_535	65536

Note how Host UIDs with the above files would imply that both namespaces owned/started by ermo and lfs users would nessarily share Host UIDs and Host GIDs with the above mapping tables; i.e. UserNS UID 1 in containers would all be owned by Host UID 1_000_000 on the system.

IFF the above is the correct interpretation, THEN it might make sense to update the qol-assist logic to instead adopt the following logic for creating user:starting_host_uid:range triplets:

If we define starting_host_uid = (UID+1) * 100_000, (if we assume that ermo is UID/GID 1000, lfs is UID/GID 1004 and root is UID/GID = 1) then we get the following, automagically generated /etc/subuid and /etc/subgid file contents:

$ cat /etc/subuid
ermo:10010000:65536
lfs:10050000:65536
root:100000:65536

$ cat /etc/subgid
ermo:10010000:65536
lfs:10040000:65536
root:100000:65536

[joebonrichie]

The actual logic should be:

We'll need the SUB_GID_MIN, SUB_GID_MAX, and, SUB_GID_COUNT variables from the login.defs file.

e.g.

SUB_GID_MIN		   100000
SUB_GID_MAX		600100000
SUB_GID_COUNT		    65536

If /etc/subgid is empty then it should be user:SUB_GID_MIN:SUB_GID_COUNT

If /etc/subgid file is pre-populated with user(s) the next user added should be should be the maximum gid present in the file + SUB_GID_COUNT.

e.g.

$ cat /etc/subgid
temp7:100000:65536
temp8:165536:65536

for new-user it should be 165536 + 65536, resulting in

$ cat /etc/subgid
temp7:100000:65536
temp8:165536:65536
new-user:231072:65536

The exact same applies to the /etc/subuid file