#!/bin/bash

if mount | grep -q "on / type aufs"; then
    cat <<EOF >&2
WARNING: Generation of wic images will fail!

Your docker host setup uses broken aufs as storage driver. Adjust the docker
configuration to use a driver (overlay, overlay2, devicemapper). You may also
need to update the host distribution (e.g. Debian Jessie -> Stretch).

EOF
fi

USER_ID=${USER_ID:-30000}

if [ $USER_ID == 0 ]; then
	# We shall run everything as root
	mkdir -p /builder

	cd /builder
	if [ -n "$1" ]; then
		exec "$@"
	else
		exec bash
	fi
else
	if ! id $USER_ID >/dev/null 2>&1; then
		# Create a non-root user that will perform the actual build
		useradd --uid $USER_ID --create-home --home-dir /builder builder
	fi

	cd /builder
	if [ -n "$1" ]; then
		exec gosu builder "$@"
	else
		exec gosu builder bash
	fi
fi