Restore fake TTY

entrypoint.sh

@@ -130,6 +130,9 @@ sed -i '/Section\s\+"Monitor"/a\    Option         "DPMS" "False"' /etc/X11/xorg
 # Prevent interference between GPUs, add this to the host or other containers running Xorg as well
 echo -e "Section \"ServerFlags\"\n    Option         \"DontVTSwitch\" \"True\"\n    Option         \"DontZap\" \"True\"\n    Option         \"AllowMouseOpenFail\" \"True\"\n    Option         \"AutoAddGPU\" \"False\"\nEndSection" | tee -a /etc/X11/xorg.conf > /dev/null
 
+# Real sudo (sudo-root) is required in Ubuntu 20.04 but not newer Ubuntu, this symbolic link enables running Xorg inside a container with `-sharevts`
+ln -snf /dev/ptmx /dev/tty7 || sudo-root ln -snf /dev/ptmx /dev/tty7 || echo 'Failed to create /dev/tty7 device'
+
 # Run Xorg server with required extensions
 /usr/lib/xorg/Xorg "${DISPLAY}" vt7 -noreset -novtswitch -sharevts -nolisten "tcp" -ac -dpi "${DISPLAY_DPI}" +extension "COMPOSITE" +extension "DAMAGE" +extension "GLX" +extension "RANDR" +extension "RENDER" +extension "MIT-SHM" +extension "XFIXES" +extension "XTEST" &