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#!/bin/sh
# leds
#
# utilities to manipulate the settings of the system leds
#

# Debian hack to avoid needing to include the while functions file.
machine(){
	echo nslu2
}
	
#
# led_set led-dir off|on|slow|fast|panic|blink|flash|user|*
#  set the given LED (expressed as a directory) to the 
#  given status.  USER_LED may be set to indicate how to
#  handle the 'user' setting.
led_user_default(){
	case "$(machine)" in
	nslu2)	echo -n "cpu-idle";;
	*)	echo -n "cpu";;
	esac
}
#
led_set(){
	local setting
	# expect led-dir state
	if test -d "$1"
	then
		setting="$2"
		case "$setting" in
		user)	if test -n "$USER_LED"
			then
				setting="$USER_LED"
			else
				setting="$(led_user_default)"
			fi;;
		esac

		case "$setting" in
		off|on)		echo -n none

				case "$setting" in
				on)	echo -n 255;;
				off)	echo -n 0;;
				esac >"$1/brightness";;

		slow|fast|panic|blink|flash)
				echo -n timer

				case "$setting" in
				flash)	echo -n 60;;
				blink)	echo -n 540;;
				slow)	echo -n 500;;
				fast)	echo -n 1500;;
				panic)	echo -n 3000;;
				esac >"$1/delay_on"

				case "$setting" in
				flash)	echo -n 540;;
				blink)	echo -n 60;;
				slow)	echo -n 500;;
				fast)	echo -n 1500;;
				panic)	echo -n 3000;;
				esac >"$1/delay_off";;

		cpu-idle)	echo -n cpu
				# these settings work well on NSLU2
				echo -n on >"$1/idle"
				echo -n flash >"$1/active";;

		*)		echo -n "$setting";;
		esac >"$1/trigger"
	else
		echo "leds: $1: no such directory" >&2
		return 1
	fi
}

#
# sysled [boot] system|user|singleuser|shutdown [error|panic|*]
#  set the system LEDs to indicate the given boot state, the function
#  will temporarily mount sysfs is necessary (using /mnt)
#
# the cases for two LEDs (ready+status)
sysled_readystatus(){
	local ready status
	# expect dir [boot](system|user) [error|panic]
	case "$3" in
	error)	ready=fast;	status=off;;
	panic)	ready=fast;	status=fast;;
	*)	case "$2" in
		bootsystem)	ready=slow;	status=slow;;
		system)		ready=on;	status=on;;
		bootuser)	ready=on;	status=slow;;
		user)		ready=user;	status=off;;
		bootsingleuser)	ready=on;	status=slow;;
		singleuser)	ready=user;	status=user;;
		bootshutdown)	ready=on;	status=slow;;
		shutdown)	ready=slow;	status=on;;
		esac;;
	esac

	led_set "$1/ready" "$ready"
	led_set "$1/status" "$status"
}
#
# the cases for one LED (just ready)
sysled_ready(){
	local ready
	# expect dir [boot](system|user) [error|panic]
	case "$3" in
	error)	ready=fast;;
	panic)	ready=panic;;
	*)	case "$2" in
		bootsystem)	ready=flash;;
		system)		ready=blink;;
		bootuser)	ready=slow;;
		user)		ready=user;;
		bootsingleuser)	ready=flash;;
		singleuser)	ready=blink;;
		bootshutdown)	ready=slow;;
		shutdown)	ready=blink;;
		esac;;
	esac

	led_set "$1/ready" "$ready"
}
#
sysled(){
	local mp st boot isst
	mp=/sys
	st=1
	boot=

	# validate arguments
	if test "$1" = boot
	then
		shift
		boot=boot
	fi
	case "$1" in
	system|user|singleuser|shutdown) :;;
	*)	echo "sysled: unknown option '$1'" >&2
		echo " usage: sysled [boot] system|user|singleuser|shutdown [error|panic|*]" >&2
		return 1;;
	esac

	if test ! -d "$mp/class/leds" && mount -t sysfs sysfs /mnt
	then
		mp=/mnt
	fi
	#
	# check for the 'ready' LED - otherwise do nothing
	if test -d "$mp/class/leds/ready"
	then
		if test -d "$mp/class/leds/status"
		then
			sysled_readystatus "$mp/class/leds" $boot"$@"
		else
			sysled_ready "$mp/class/leds" $boot"$@"
		fi
	fi
	#
	# clean up
	test "$mp" = /mnt && umount /mnt
	return "$st"
}

#
# beep {arguments}
#  emit a beep
#  does nothing if there is no beep executable, is very
#  quiet in the presence of errors
beep(){
	local arg
	arg=
	test "$1" = beep && shift
	if test -x /bin/beep
	then
		test -c /dev/buzzer && arg="-e /dev/buzzer"
		/bin/beep $arg "$@" 2>/dev/null
	fi
	return 0
}

#
# leds_help
#  be helpful
# leds <led> off|on|slow|fast|panic|blink|flash|user|*
# leds [boot] system|user|singleuser|shutdown [error|panic|*]
leds_help(){
	echo "leds: change the setting of the LEDs" >&2
	echo " usage:" >&2
	echo "  leds [boot] system|user|singleuser|shutdown [error|panic|*]" >&2
	echo "    set leds during system boot to indicate a particular boot" >&2
	echo "    state.  'boot' means that the system is transitioning to" >&2
	echo "    the new state.  'error' or 'panic' means a (potentially)" >&2
	echo "    recoverable error or an unrecoverable error ('panic') has" >&2
	echo "    occured." >&2
	echo "  <led> off|on|slow|fast|panic|blink|flash|user|cpu|cpu-idle" >&2
	echo "    set the named led to the given display, an arbitrary led" >&2
	echo "    trigger may be given.  'user' will use the default specified" >&2
	echo "    in USER_LED from /etc/default/rcS, if not specified a cpu" >&2
	echo "    activity setting appropriate to the machine is selected" >&2
	echo "  beep {args}" >&2
	echo "    if possible cause the machine to emit a beep" >&2
}

#
# the real command, if required
case "$1" in
boot|system|user|singleuser|shutdown)
	sysled "$@";;

beep)	beep "$@";;

""|-*)	leds_help;;
help)	leds_help;;

leds)	# just load the functions
	;;

*)	led_set /sys/class/leds/"$@"
esac