#!/bin/ash

wait_for_iface() {
	local DEVICE=$1
	local TIMEOUT=10
	local state laststate current relax
	local want=
	local ret=1 # error
	[ -n "$2" ] && TIMEOUT="$2"
	echo -n "Waiting ${TIMEOUT}s for interface $DEVICE: "
	TIMEOUT="$(( TIMEOUT * 2 ))"
	# Some systems don't have operstate. Seems to be hardware dependent
	[ -e "/sys/class/net/${DEVICE}/operstate" ] || sleep 1
	[ -e "/sys/class/net/${DEVICE}/operstate" ] && want="up"
	[ -e "/sys/class/net/${DEVICE}/carrier" ] && want="${want}1"
	if [ -n "$want" ]; then
		relax=$(( TIMEOUT / 3 ))
		[ "$relax" -lt 8 ] && relax=8
		current=0
		while true; do
			# check linkstate
			state="$( cat "/sys/class/net/${DEVICE}/operstate" 2> /dev/null )"
			state="${state}$( cat "/sys/class/net/${DEVICE}/carrier" 2> /dev/null )"
			[ "$state" != "$laststate" ] && echo -n "[$state]"
			laststate="$state"
			if [ "$state" = "$want" ]; then
				ret=0
				break
			fi
			if [ "$current" -gt "$relax" ] && [ "$state" = "unknown1" ]; then
				echo -n "better than nothing"
				ret=0
				break
			fi
			current=$(( current + 1 )) # don't wait forever, the pcnet iface of vmware will never be "up" although it's working
			if [ "$current" -ge "$TIMEOUT" ];then
				echo -n "TIMEOUT"
				break
			fi
			# else
			echo -n "."
			usleep 500000
		done
	else
		# we really don't have a operstate .. then just wait a sec and hope for the best.
		sleep 1
		echo -n "... no operstate or carrier, let's hope for the best..."
	fi
	echo
	return "$ret"
}
true