#!/bin/sh
# vim:set filetype=sh:

set -e

: "${LIBDIR:=$PREFIX/lib}"
. "$LIBDIR/tiny-cloud/common"

if [ -z "$MDEV" ] || [ -z "$ACTION" ]; then
	log crit "MDEV or ACTION undefined, aborting"
fi

IFACE_CFG=/etc/network/interfaces

ip() {
	local v=-4 lev=info
	if [ "$1" = '-4' ] || [ "$1" = '-6' ]; then
		v="$1"
		shift
	fi
	local op="$2"

	[ "$op" = show ] && lev=debug
	if /sbin/ip "$v" "$@" || [ -n "$FAIL_OK" ]; then
		log "$lev" "OK: ip $v $*"
	else
		log err "FAIL: ip $v $*"
	fi
}

interface_up() {
	log info "Bringing up $MDEV"
	# umask so udhcpc PID file isn't non-owner writeable
	(umask 0022 && ifup "$MDEV")
}

cleanup_interface() {
	local v pref rtable="${MDEV#eth}"
	let rtable+=10000

	log info "Cleaning up $MDEV"

	# kill related udhcpc, don't panic if it's not there
	kill "$(cat "/run/udhcpc.$MDEV.pid")" || true

	# tidy up /run/ifstate, if it exists
	[ -f /run/ifstate ] && sed -i -e "/^$MDEV=/d" /run/ifstate
	rm -f /run/ifstate."$MDEV".lock

	# remove related rules
	for v in 4 6; do
		for pref in $(ip -"$v" rule show table "$rtable" | cut -d: -f1); do
			ip -"$v" rule del pref "$pref"
		done
	done
}

is_networking_started() { service networking status -q 2>/dev/null; }

log info "STARTING: $ACTION $MDEV"

if exec 200>>"$IFACE_CFG"; then
	if flock 200; then
		case $ACTION in
			add|"")
				assemble-interfaces
				is_networking_started && interface_up
				;;
			remove)
				assemble-interfaces
				is_networking_started && cleanup_interface
				;;
			*)
				log err "Unknown action '$ACTION'"
				exit 1
				;;
		esac
	else
		log err "Unable to flock $IFACE_CFG"
		exit 1
	fi
else
	log err "Unable to assign fd 200 to flock $IFACE_CFG"
	exit 1
fi

log info "FINISHED: $ACTION $MDEV"