Launch an application in another X-session as non-root

Question

How to start an X server as root with a session of non-root application?

Should be something like

xinit 'su -c openbox user' -- :1

but working :)

Answer 1

Try

su -c 'startx openbox -- :1' user

Edit: Also try running

X :1 &
su -c 'DISPLAY=:1 openbox &' user

Answer 2

It seems to be that the only way is to create temporary .xinitrc file. Here's the script:

#!/usr/bin/env bash

username="$USER"
let xdisplay=${DISPLAY:1}+1

# Temporary xinitrc
temp_xinit="$(tempfile -p '.xinit' -s 'rc')" || exit
trap "rm -f -- '$temp_xinit'" EXIT

# Launch X
echo "sudo -u $username $@" > "$temp_xinit"
sudo xinit "$temp_xinit" -- :$xdisplay

Example usage:

$ Xnew.sh /usr/local/games/braid [..options...]