The BSDs will likely never work

[Earnestly]

Due to my design choice of coupling the tty number to Xorg's vt argument and DISPLAY value it may mean neither OpenBSD or FreeBSD will ever work.

The reason for this seems to be due to how FreeBSD and OpenBSD won't let the Xorg server take over an active tty. Instead it generates a cryptic error message telling us that (EE) Unrecognized option: vt0.

Additionally OpenBSD will not let users run ps -o tty= $$ so this approach isn't viable to start with either.

There are a few potential solutions to this, some which seem to be mutually exclusive between platforms.

• The first, and easiest solution for FreeBSD and OpenBSD is to simply not specify the vt argument and let the Xorg server select one that is available. Unfortunately this doesn't work on Linux (when using rootless Xorg servers thanks to systemd-logind).
• The second is to unconditionally increment the vt argument based on the tty number we get. However this is not a reliable heuristic as the second tty may also be used under FreeBSD which lands us back at square one.
• Start using platform detection.

None of these are going to be viable. Instead FreeBSD and OpenBSD would probably take advantage of /etc/ttys which appears to offer a better approach to managing Xorg servers anyway. For OpenBSD specifically they also have xenodm(1) as well.