#!/bin/bash
set -euo pipefail
[[ -r /run/fds/network/interfaces ]] || exit 0
mapfile -t interfaces < /run/fds/network/interfaces
for interface in "${interfaces[@]}"; do
    [[ $interface =~ ^[a-zA-Z0-9][a-zA-Z0-9_.-]{0,14}$ ]]
    if [[ -e /sys/class/net/$interface ]]; then
        ip link set dev "$interface" down || [[ ! -e /sys/class/net/$interface ]]
    fi
done
: > /run/fds/resolv.conf