#!/bin/bash
#
# Simple script implementing a temperature dependent fan speed control
#
# Version 0.67
#
# Usage: fancontrol [CONFIGFILE]
#
# Dependencies:
#   bash, egrep, sed, cut, sleep, 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) 2007-2008 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

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

declare -i pwmval

function LoadConfig {
	echo "Loading configuration from $1 ..."
	# grep configuration from file
	INTERVAL=`egrep '^INTERVAL=.*$' $1 | sed -e 's/INTERVAL=//g'`
	FCTEMPS=`egrep '^FCTEMPS=.*$' $1 | sed -e 's/FCTEMPS=//g'`
	MINTEMP=`egrep '^MINTEMP=.*$' $1 | sed -e 's/MINTEMP=//g'`
	MAXTEMP=`egrep '^MAXTEMP=.*$' $1 | sed -e 's/MAXTEMP=//g'`
	MINSTART=`egrep '^MINSTART=.*$' $1 | sed -e 's/MINSTART=//g'`
	MINSTOP=`egrep '^MINSTOP=.*$' $1 | sed -e 's/MINSTOP=//g'`
	# optional settings:
	FCFANS=`egrep '^FCFANS=.*$' $1 | sed -e 's/FCFANS=//g'`
	MINPWM=`egrep '^MINPWM=.*$' $1 | sed -e 's/MINPWM=//g'`
	MAXPWM=`egrep '^MAXPWM=.*$' $1 | sed -e 's/MAXPWM=//g'`

	# Check whether all mandatory settings are set
	if [[ -z ${INTERVAL} || -z ${FCTEMPS} || -z ${MINTEMP} || -z ${MAXTEMP} || -z ${MINSTART} || -z ${MINSTOP} ]]
	then
		echo "Some mandatory settings missing, please check your config file!"
		exit 1
	fi
	if [ "$INTERVAL" -le 0 ]
	then
		echo "Error in configuration file:"
		echo "INTERVAL must be at least 1"
		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:"
			echo "FCTEMPS value is improperly formatted"
			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[$fcvcount]}" |cut -d'=' -f2`
		AFCMINTEMP[$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

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

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

DIR=/proc/sys/dev/sensors
if [ ! -d $DIR ]
then
	# For Linux 2.6, detect if config file uses the hwmon class or not yet
	if echo "${AFCPWM[0]}" | egrep -q '^hwmon[0-9]'
	then
		SDIR=/sys/class/hwmon
	else
		SDIR=/sys/bus/i2c/devices
	fi

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

# $1 = pwm file name
function pwmdisable()
{
	if [ -n "$SYSFS" ]
	then
		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
			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
	else
		echo $MAX 0 > $1
	fi
}

# $1 = pwm file name
function pwmenable()
{
	if [ "$SYSFS" = "1" ]
	then
		ENABLE=${1}_enable
		if [ -f $ENABLE ]
		then
			echo 1 > $ENABLE 2> /dev/null
			if [ $? -ne 0 ]
			then
				return 1
			fi
		fi
		echo $MAX > $1
	else
		echo $MAX 1 > $1
	fi
}

function restorefans()
{
	local status=$1
	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

# main function
function UpdateFanSpeeds {
	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[$fcvcount]}
		mint=${AFCMINTEMP[$fcvcount]}
		maxt=${AFCMAXTEMP[$fcvcount]}
		minsa=${AFCMINSTART[$fcvcount]}
		minso=${AFCMINSTOP[$fcvcount]}
		minpwm=${AFCMINPWM[$fcvcount]}
		maxpwm=${AFCMAXPWM[$fcvcount]}

		read tval < ${tsens}
		if [ $? -ne 0 ]
		then
			echo "Error reading temperature from $DIR/$tsens"
			restorefans 1
		fi
		if [ "$SYSFS" = "1" ]
		then
			let tval="($tval+500)/1000"
		else
			tval=`echo ${tval} | cut -d' ' -f3 | cut -d'.' -f1`
		fi

		read pwmpval < ${pwmo}
		if [ $? -ne 0 ]
		then
			echo "Error reading PWM value from $DIR/$pwmo"
			restorefans 1
		fi
		if [ "$SYSFS" != "1" ]
		then
			pwmpval=`echo ${pwmpval} | cut -d' ' -f1`
		fi

		# If fanspeed-sensor output shall be used, do it
		if [[ -n ${fan} ]]
		then
			read fanval < ${fan}
			if [ $? -ne 0 ]
			then
				echo "Error reading Fan value from $DIR/$fan"
				restorefans 1
			fi
			if [ "$SYSFS" != "1" ]
			then
				fanval=`echo ${fanval} | cut -d' ' -f2`
			fi
		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"
		fi

		if (( $tval <= $mint ))
		  then pwmval=$minpwm # below min temp, use defined min pwm
		elif (( $tval >= $maxt ))
		  then pwmval=$maxpwm # over max temp, use defined max pwm
		else
		  # calculate the new value from temperature and settings
		  pwmval="(${tval}-${mint})*(${maxpwm}-${minso})/(${maxt}-${mint})+${minso}"
		  if [ $pwmpval -eq 0 -o $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"
			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"
		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