This is far from ideal: we end up with 2 extra X11 servers (the Xvfb and Xnest running inside it) and performance is not going to be great. But this is fairly easy to add, so why not?

Server must tell the clients that it supports this mode (==it has Xnest installed and this is enabled in config). Then on app start we run Xnest and use the old port probing code to launch the real app against the Xnest display. (not going to do pre-launch mode for this - not worth it)

Should be a pretty straight forward swap. No reason to use yet another network library (raw sockets in this case)

We should probably watch the output of the Xvnc process like we do for NX. Looks like we can detect if the session is connected or not: vncext: Listening for VNC connections on port 16064 Means no need to test using a wait_for_socket. Connections: accepted: 127.0.0.1::51920 Means we can remove the need for the client to set the CONNECTED status. Connections: closed: 127.0.0.1::51920 (Clean disconnection) As above for AVAILABLE.

Log Xvnc output to file ~/.Xvnc/:DISPLAY.log

Note: the code has only been tested with tigervnc...