#!/bin/bash
#
# Simple script implementing a temperature dependent fan speed control
# Supported Linux kernel versions: 2.6.5 and later
#
# Version 0.70
#
# Usage: fancontrol [CONFIGFILE]
#
# Dependencies:
#   bash, egrep, sed, cut, sleep, readlink, lm_sensors :)
#
# Please send any questions, comments or success stories to
# marius.reiner@hdev.de
# Thanks!
#
# For configuration instructions and warnings please see fancontrol.txt, which
# can be found in the doc/ directory or at the website mentioned above.
#
#
#    Copyright 2003 Marius Reiner <marius.reiner@hdev.de>
#    Copyright (C) 2007-2009 Jean Delvare <khali@linux-fr.org>
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
#    MA 02110-1301 USA.
#
#

PIDFILE="/var/run/fancontrol.pid"

#DEBUG=1
MAX=255

function LoadConfig
{
	local fcvcount fcv

	echo "Loading configuration from $1 ..."
	if [ ! -r "$1" ]
	then
		echo "Error: Can't read configuration file" >&2
		exit 1
	fi

	# grep configuration from file
	INTERVAL=`egrep '^INTERVAL=.*$' $1 | sed -e 's/INTERVAL=//g'`
	DEVPATH=`egrep '^DEVPATH=.*$' $1 | sed -e 's/DEVPATH= *//g'`
	DEVNAME=`egrep '^DEVNAME=.*$' $1 | sed -e 's/DEVNAME= *//g'`
	FCTEMPS=`egrep '^FCTEMPS=.*$' $1 | sed -e 's/FCTEMPS=//g'`
	MINTEMP=`egrep '^MINTEMP=.*$' $1 | sed -e 's/MINTEMP=//g'`
	MAXTEMP=`egrep '^MAXTEMP=.*$' $1 | sed -e 's/MAXTEMP=//g'`
	MINSTART=`egrep '^MINSTART=.*$' $1 | sed -e 's/MINSTART=//g'`
	MINSTOP=`egrep '^MINSTOP=.*$' $1 | sed -e 's/MINSTOP=//g'`
	# optional settings:
	FCFANS=`egrep '^FCFANS=.*$' $1 | sed -e 's/FCFANS=//g'`
	MINPWM=`egrep '^MINPWM=.*$' $1 | sed -e 's/MINPWM=//g'`
	MAXPWM=`egrep '^MAXPWM=.*$' $1 | sed -e 's/MAXPWM=//g'`
	THYST=`egrep '^THYST=.*$' $1 | sed -e 's/THYST=//g'`
	echo 
	# Check whether all mandatory settings are set
	if [[ -z ${INTERVAL} || -z ${FCTEMPS} || -z ${MINTEMP} || -z ${MAXTEMP} || -z ${MINSTART} || -z ${MINSTOP} ]]
	then
		echo "Some mandatory settings missing, please check your config file!" >&2
		exit 1
	fi
	if [ "$INTERVAL" -le 0 ]
	then
		echo "Error in configuration file:" >&2
		echo "INTERVAL must be at least 1" >&2
		exit 1
	fi

	# write settings to arrays for easier use and print them
	echo
	echo "Common settings:"
	echo "  INTERVAL=$INTERVAL"

	let fcvcount=0
	for fcv in $FCTEMPS
	do
		if ! echo $fcv | egrep -q '='
		then
			echo "Error in configuration file:" >&2
			echo "FCTEMPS value is improperly formatted" >&2
			exit 1
		fi

		AFCPWM[$fcvcount]=`echo $fcv |cut -d'=' -f1`
		AFCTEMP[$fcvcount]=`echo $fcv |cut -d'=' -f2`
		AFCFAN[$fcvcount]=`echo $FCFANS |sed -e 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		AFCFANFAULT[$fcvcount]=`echo "${AFCFAN[$fcvcount]}" |sed -e 's/input/fault/g'`
		AFCMINTEMP[$fcvcount]=`echo $MINTEMP |sed -e 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		AFCMAXTEMP[$fcvcount]=`echo $MAXTEMP |sed -e 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		AFCMINSTART[$fcvcount]=`echo $MINSTART |sed -e 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		AFCMINSTOP[$fcvcount]=`echo $MINSTOP |sed -e 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		AFCMINPWM[$fcvcount]=`echo $MINPWM |sed -e 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		[ -z "${AFCMINPWM[$fcvcount]}" ] && AFCMINPWM[$fcvcount]=0
		AFCMAXPWM[$fcvcount]=`echo $MAXPWM |sed -e 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		[ -z "${AFCMAXPWM[$fcvcount]}" ] && AFCMAXPWM[$fcvcount]=255
		AFCTHYST[$fcvcount]=`echo $THYST |sed -e 's/ /\n/g' |egrep "${AFCPWM[$fcvcount]}" |cut -d'=' -f2`
		[ -z "${AFCTHYST[$fcvcount]}" ] && AFCTHYST[$fcvcount]=0

		# verify the validity of the settings
		if [ "${AFCMINTEMP[$fcvcount]}" -ge "${AFCMAXTEMP[$fcvcount]}" ]
		then
			echo "Error in configuration file (${AFCPWM[$fcvcount]}):" >&2
			echo "MINTEMP must be less than MAXTEMP" >&2
			exit 1
		fi
		if [ "${AFCMAXPWM[$fcvcount]}" -gt 255 ]
		then
			echo "Error in configuration file (${AFCPWM[$fcvcount]}):" >&2
			echo "MAXPWM must be at most 255" >&2
			exit 1
		fi
		if [ "${AFCMINSTOP[$fcvcount]}" -ge "${AFCMAXPWM[$fcvcount]}" ]
		then
			echo "Error in configuration file (${AFCPWM[$fcvcount]}):" >&2
			echo "MINSTOP must be less than MAXPWM" >&2
			exit 1
		fi
		if [ "${AFCMINSTOP[$fcvcount]}" -lt "${AFCMINPWM[$fcvcount]}" ]
		then
			echo "Error in configuration file (${AFCPWM[$fcvcount]}):" >&2
			echo "MINSTOP must be greater than or equal to MINPWM" >&2
			exit 1
		fi
		if [ "${AFCMINPWM[$fcvcount]}" -lt 0 ]
		then
			echo "Error in configuration file (${AFCPWM[$fcvcount]}):" >&2
			echo "MINPWM must be at least 0" >&2
			exit 1
		fi

		echo
		echo "Settings for ${AFCPWM[$fcvcount]}:"
		echo "  Depends on ${AFCTEMP[$fcvcount]}"
		echo "  Controls ${AFCFAN[$fcvcount]}"
		echo "  MINTEMP=${AFCMINTEMP[$fcvcount]}"
		echo "  MAXTEMP=${AFCMAXTEMP[$fcvcount]}"
		echo "  MINSTART=${AFCMINSTART[$fcvcount]}"
		echo "  MINSTOP=${AFCMINSTOP[$fcvcount]}"
		echo "  MINPWM=${AFCMINPWM[$fcvcount]}"
		echo "  MAXPWM=${AFCMAXPWM[$fcvcount]}"
		echo "  THYST=${AFCTHYST[$fcvcount]}"
		let fcvcount=fcvcount+1
	done
	echo
}

function CheckFanFault()
{
	let fancount=0
	while (( $fancount < ${#AFCFANFAULT[@]} )) # go through all fan fault.
	do
		fault=`cat ${AFCFANFAULT[$fancount]}`
		if [[ "$fault" == "1" ]]
		then
			return 1 # fan fault detected
		fi
		let fancount=$fancount+1
	done
	return 0
}

function DevicePath()
{
	if [ -h "$1/device" ]
	then
		readlink -f "$1/device" | sed -e 's/^\/sys\///'
	fi
}

function DeviceName()
{
	if [ -r "$1/name" ]
	then
		cat "$1/name" | sed -e 's/[[:space:]=]/_/g'
	elif [ -r "$1/device/name" ]
	then
		cat "$1/device/name" | sed -e 's/[[:space:]=]/_/g'
	fi
}

function ValidateDevices()
{
	local OLD_DEVPATH="$1" OLD_DEVNAME="$2" outdated=0
	local entry device name path

	for entry in $OLD_DEVPATH
	do
		device=`echo "$entry" | sed -e 's/=[^=]*$//'`
		path=`echo "$entry" | sed -e 's/^[^=]*=//'`

		if [ "`DevicePath "$device"`" != "$path" ]
		then
			echo "Device path of $device has changed" >&2
			outdated=1
		fi
	done

	for entry in $OLD_DEVNAME
	do
		device=`echo "$entry" | sed -e 's/=[^=]*$//'`
		name=`echo "$entry" | sed -e 's/^[^=]*=//'`

		if [ "`DeviceName "$device"`" != "$name" ]
		then
			echo "Device name of $device has changed" >&2
			outdated=1
		fi
	done

	return $outdated
}

# Check that all referenced sysfs files exist
function CheckFiles
{
	local outdated=0 fcvcount pwmo tsen fan

	let fcvcount=0
	while (( $fcvcount < ${#AFCPWM[@]} )) # go through all pwm outputs
	do
		pwmo=${AFCPWM[$fcvcount]}
		if [ ! -w $pwmo ]
		then
			echo "Error: file $pwmo doesn't exist" >&2
			outdated=1
		fi
		let fcvcount=$fcvcount+1
	done

	let fcvcount=0
	while (( $fcvcount < ${#AFCTEMP[@]} )) # go through all temp inputs
	do
		tsen=${AFCTEMP[$fcvcount]}
		if [ ! -r $tsen ]
		then
			echo "Error: file $tsen doesn't exist" >&2
			outdated=1
		fi
		let fcvcount=$fcvcount+1
	done

	let fcvcount=0
	while (( $fcvcount < ${#AFCFAN[@]} )) # go through all fan inputs
	do
		# A given PWM output can control several fans
		for fan in $(echo ${AFCFAN[$fcvcount]} | sed -e 's/+/ /')
		do
			if [ ! -r $fan ]
			then
				echo "Error: file $fan doesn't exist" >&2
				outdated=1
			fi
		done
		let fcvcount=$fcvcount+1
	done

	if [ $outdated -eq 1 ]
	then
		echo >&2
		echo "At least one referenced file is missing. Either some required kernel" >&2
		echo "modules haven't been loaded, or your configuration file is outdated." >&2
		echo "In the latter case, you should run pwmconfig again." >&2
	fi

	return $outdated
}

if [ "$1" == "--check" ]
then
	if [ -f "$2" ]
	then
		LoadConfig $2
	else
		LoadConfig /etc/fancontrol
	fi
	exit 0
fi

if [ -f "$1" ]
then
	LoadConfig $1
else
	LoadConfig /etc/fancontrol
fi

# Detect path to sensors
if echo "${AFCPWM[0]}" | egrep -q '^/'
then
	DIR=/
elif echo "${AFCPWM[0]}" | egrep -q '^hwmon[0-9]'
then
	DIR=/sys/class/hwmon
elif echo "${AFCPWM[0]}" | egrep -q '^[1-9]*[0-9]-[0-9abcdef]{4}'
then
	DIR=/sys/bus/i2c/devices
else
	echo "$0: Invalid path to sensors" >&2
	exit 1
fi

if [ ! -d $DIR ]
then
	echo $0: 'No sensors found! (did you load the necessary modules?)' >&2
	exit 1
fi
cd $DIR

# Check for configuration change
# if [ "$DIR" != "/" ] && [ -z "$DEVPATH" -o -z "$DEVNAME" ]
# then
#    echo "Configuration is too old, please run pwmconfig again" >&2
# 	 exit 1
# fi

if [ "$DIR" = "/" -a -n "$DEVPATH" ]
then
	echo "Unneeded DEVPATH with absolute device paths" >&2
	exit 1
fi
if ! ValidateDevices "$DEVPATH" "$DEVNAME"
then
	echo "Configuration appears to be outdated, please run pwmconfig again" >&2
	exit 1
fi
CheckFiles || exit 1

if [ -f "$PIDFILE" ]
then
	echo "File $PIDFILE exists, is fancontrol already running?" >&2
	exit 1
fi
echo $$ > "$PIDFILE"

# $1 = pwm file name
function pwmdisable()
{
	local ENABLE=${1}_enable

	# No enable file? Just set to max
	if [ ! -f $ENABLE ]
	then
		echo $MAX > $1
		return 0
	fi

	# Try pwmN_enable=0
	echo 0 > $ENABLE 2> /dev/null
	if [ `cat $ENABLE` -eq 0 ]
	then
		# Success
		echo $MAX > $1
		return 0
	fi

	# It didn't work, try pwmN_enable=1 pwmN=255
	echo 1 > $ENABLE 2> /dev/null
	echo $MAX > $1
	if [ `cat $ENABLE` -eq 1 -a `cat $1` -ge 190 ]
	then
		# Success
		return 0
	fi

	# Nothing worked
	echo "$ENABLE stuck to" `cat $ENABLE` >&2
	return 1
}

# $1 = pwm file name
function pwmenable()
{
	local ENABLE=${1}_enable

	if [ -f $ENABLE ]
	then
		echo 1 > $ENABLE 2> /dev/null
		if [ $? -ne 0 ]
		then
			return 1
		fi
	fi
	echo $MAX > $1
}

function restorefans()
{
	local status=$1 fcvcount pwmo

	echo 'Aborting, restoring fans...'
	let fcvcount=0
	while (( $fcvcount < ${#AFCPWM[@]} )) # go through all pwm outputs
	do
		pwmo=${AFCPWM[$fcvcount]}
		pwmdisable $pwmo
		let fcvcount=$fcvcount+1
	done
	echo 'Verify fans have returned to full speed'
	rm -f "$PIDFILE"
	exit $status
}

trap 'restorefans 0' SIGQUIT SIGTERM
trap 'restorefans 1' SIGHUP SIGINT

function upperBound
{
    # $1: temperature
    # $2: Tmin
    # $3: Tmax
    # $4: MinPWM
    # $5: MaxPWM
    # $6 Thyst
    # upper_bound = (temperature-Tmin+2) * (MaxPWM-MinPWM)/(Tmax-Tmin)+MinPWM
    let a="($1-$2+$6)*($5-$4)/($3-$2)+$4"
    up_b=$a
}
function lowerBound
{
    # $1: temperature
    # $2: Tmin
    # $3: Tmax
    # $4: MinPWM
    # $5: MaxPWM
    # $6 Thyst
    # lower_bound = (temperature-Tmin) *(MaxPWM-MinPWM)/(Tmax-Tmin)+MinPWM
    let a="($1-$2)*($5-$4)/($3-$2)+$4"
    lw_b=$a
}

# main function
function UpdateFanSpeeds
{
	local fcvcount
	local pwmo tsens fan mint maxt minsa minso minpwm maxpwm tHyst
	local tval pwmpval fanval min_fanval one_fan one_fanval
	local -i pwmval

	let fcvcount=0
	while (( $fcvcount < ${#AFCPWM[@]} )) # go through all pwm outputs
	do
		#hopefully shorter vars will improve readability:
		pwmo=${AFCPWM[$fcvcount]}
		tsens=${AFCTEMP[$fcvcount]}
		fan=${AFCFAN[$fcvcount]}
		let mint="${AFCMINTEMP[$fcvcount]}*1000"
		let maxt="${AFCMAXTEMP[$fcvcount]}*1000"
		minsa=${AFCMINSTART[$fcvcount]}
		minso=${AFCMINSTOP[$fcvcount]}
		minpwm=${AFCMINPWM[$fcvcount]}
		maxpwm=${AFCMAXPWM[$fcvcount]}
		let tHyst="${AFCTHYST[$fcvcount]}*1000"

		#if some fan fault detected all pwm=100%
		CheckFanFault
		if [ $? -ne 0 ]
		then
			echo $MAX > $pwmo
			let fcvcount=$fcvcount+1
			continue			
		fi	

		read tval < ${tsens}
		if [ $? -ne 0 ]
		then
			echo "Error reading temperature from $DIR/$tsens"
			restorefans 1
		fi

		read pwmpval < ${pwmo}
		if [ $? -ne 0 ]
		then
			echo "Error reading PWM value from $DIR/$pwmo"
			restorefans 1
		fi

		# If fanspeed-sensor output shall be used, do it
		if [[ -n ${fan} ]]
		then
			min_fanval=100000
			fanval=
			# A given PWM output can control several fans
			for one_fan in $(echo $fan | sed -e 's/+/ /')
			do
				read one_fanval < ${one_fan}
				if [ $? -ne 0 ]
				then
					echo "Error reading Fan value from $DIR/$one_fan" >&2
					restorefans 1
				fi

				# Remember the minimum, it only matters if it is 0
				if [ $one_fanval -lt $min_fanval ]
				then
					min_fanval=$one_fanval
				fi

				if [ -z "$fanval" ]
				then
					fanval=$one_fanval
				else
					fanval="$fanval/$one_fanval"
				fi
			done
		else
			fanval=1  # set it to a non zero value, so the rest of the script still works
		fi

		# debug info
		if [ "$DEBUG" != "" ]
		then
			echo "pwmo=$pwmo"
			echo "tsens=$tsens"
			echo "fan=$fan"
			echo "mint=$mint"
			echo "maxt=$maxt"
			echo "minsa=$minsa"
			echo "minso=$minso"
			echo "minpwm=$minpwm"
			echo "maxpwm=$maxpwm"
			echo "tval=$tval"
			echo "pwmpval=$pwmpval"
			echo "fanval=$fanval"
			echo "min_fanval=$min_fanval"
			echo "tHyst=$tHyst"
		fi
		pwmval=$pwmpval
		if (( $tval+$tHyst <= $mint ))
			then pwmval=$minpwm # below min temp, use defined min pwm
		elif (( $tval >= $maxt ))
			then pwmval=$maxpwm # over max temp, use defined max pwm
		elif (( $tval+$tHyst >= $maxt )) && (( $pwmpval == $maxpwm ))
			then pwmval=$maxpwm
		else
			# calculate the new value from temperature and settings
			# pwmval="(${tval}-${mint})*(${maxpwm}-${minso})/(${maxt}-${mint})+${minso}
			lowerBound ${tval} ${mint} ${maxt} ${minpwm} ${maxpwm} ${tHyst}
			lb=$lw_b
			upperBound ${tval} ${mint} ${maxt} ${minpwm} ${maxpwm} ${tHyst}
			ub=$up_b

			if [ "$DEBUG" != "" ]
			then
				echo "old pwm=$pwmval lw_b=$lw_b up_b=$up_b"
			fi

			if [[ "$pwmval" -gt "$ub" ]]
			then
				pwmval=$ub
			else
				if [[ "$pwmval" -lt "$lb" ]]
				then
						pwmval=$lb
				fi
			fi

			if [ $pwmpval -eq 0 -o $min_fanval -eq 0 ]
			then # if fan was stopped start it using a safe value
				echo $minsa > $pwmo
				# Sleep while still handling signals
				sleep 1 &
				wait $!
			fi
		fi
		echo $pwmval > $pwmo # write new value to pwm output
		if [ $? -ne 0 ]
		then
			echo "Error writing PWM value to $DIR/$pwmo" >&2
			restorefans 1
		fi
		if [ "$DEBUG" != "" ]
		then
			echo "new pwmval=$pwmval"
		fi
		let fcvcount=$fcvcount+1
	done
}

echo 'Enabling PWM on fans...'
let fcvcount=0
while (( $fcvcount < ${#AFCPWM[@]} )) # go through all pwm outputs
do
	pwmo=${AFCPWM[$fcvcount]}
	pwmenable $pwmo
	if [ $? -ne 0 ]
	then
		echo "Error enabling PWM on $DIR/$pwmo" >&2
		restorefans 1
	fi
	let fcvcount=$fcvcount+1
done

echo 'Starting automatic fan control...'

# main loop calling the main function at specified intervals
while true
do
	UpdateFanSpeeds
	# Sleep while still handling signals
	sleep $INTERVAL &
	wait $!
done