qubes-installer-qubes-os/anaconda/data/systemd/anaconda-generator

#!/bin/bash
# anaconda-generator: generate services needed for anaconda operation

# set up dirs
systemd_dir=/lib/systemd/system
target_dir=$systemd_dir/anaconda.target.wants
mkdir -p $target_dir

# create symlink anaconda.target.wants/SERVICE@TTY.service
service_on_tty() {
    local service="$1" tty="$2"
    local service_instance="${service/@.service/@$tty.service}"
    ln -sf $systemd_dir/$service $target_dir/$service_instance
}

# find the real tty for /dev/console
tty="console"
while [ -f /sys/class/tty/$tty/active ]; do
    tty=$(< /sys/class/tty/$tty/active)
    tty=${tty##* } # last item in the list
done
consoletty="$tty"

# put anaconda's tmux session on the console
service_on_tty anaconda-tmux@.service $consoletty

# put a shell on the first virtualization console we find
for tty in hvc0 hvc1 xvc0 hvsi0 hvsi1 hvsi2; do
    [ "$tty" = "$consoletty" ] && continue
    if [ -d /sys/class/tty/$tty ]; then
        service_on_tty anaconda-shell@.service $tty
    fi
done