[systemd-devel] DynamicUser shared by service instances

[sqwishy]

Hi.

I was looking at how dynamic users are implemented and noticed that instances seem to
share one dynamic user within their service. In the example below, I have an attached
portable service with StateDirectory=derp-%i

    # ls -dn /var/lib/private/derp-{foo,bar}
    drwxr-xr-x 2 64000 64000 4096 Sep  2 17:59 /var/lib/private/derp-bar/
    drwxr-xr-x 2 63000 63000 4096 Sep  2 17:59 /var/lib/private/derp-foo/

    # systemctl start f30-derp@{foo,bar}

    # ls -dn /var/lib/private/derp-{foo,bar}
    drwxr-xr-x 2 63000 63000 4096 Sep  2 17:59 /var/lib/private/derp-bar/
    drwxr-xr-x 2 63000 63000 4096 Sep  2 17:59 /var/lib/private/derp-foo/

    # ls -l /run/systemd/dynamic-uid/
    total 4
    -rw------- 1 root root 9 Sep  2 18:12 63000
    lrwxrwxrwx 1 root root 8 Sep  2 18:12 direct:63000 -> f30-derp
    lrwxrwxrwx 1 root root 5 Sep  2 18:12 direct:f30-derp -> 63000

Normally the state directories are created under the same owner, I set different owners
explicitly to see that the second instance's directory is chowned.

I guess I'm wondering if this behaviour is intentional? I found it surprising but that
might just be me.