#!/bin/bash
#
# dasdstat - Tool to print DASD statistics data as formatted table
#
# Copyright IBM Corp. 2011, 2017
#
# s390-tools is free software; you can redistribute it and/or modify
# it under the terms of the MIT license. See LICENSE for details.
#

function print_usage() {
	cat <<-EOD
Usage: $CMD <options> [<statistic>]

<options> ::=
        -e|--enable
                Enable the statistics.
        -d|--disable
                Disable the statistics.
        -r|--reset
                Reset the statistics.
        -i|--directory <directory>
                Specify the directory in which the statistics can be found.
        -h|--help
                Print this text and exit.
        -l|--long
                Print more detailed information, e.g differentiate between
                read and write requests.
        -c|--columns <number>
                Format the output in a table with the given number of columns.
        -w|--column-width <width>
                Set the minimum width of the columns in the output table.
        -V|--verbose
                Print more verbose information.
        -v|--version
                Show tools and command version.

<statistic>
        Limit operation to one or more statistic.
	EOD
}

function print_version()
{
	echo "$CMD: version %S390_TOOLS_VERSION%"
	echo "Copyright IBM Corp. 2011, 2017"
}

function unset_known_variables() {
	unset start_time
	unset total_requests
	unset total_sectors
	unset total_pav
	unset total_hpf
	unset histogram_sectors
	unset histogram_io_times
	unset histogram_io_times_weighted
	unset histogram_time_build_to_ssch
	unset histogram_time_ssch_to_irq
	unset histogram_time_ssch_to_irq_weighted
	unset histogram_time_irq_to_end
	unset histogram_ccw_queue_length
	unset total_read_requests
	unset total_read_sectors
	unset total_read_pav
	unset total_read_hpf
	unset histogram_read_sectors
	unset histogram_read_times
	unset histogram_read_time_build_to_ssch
	unset histogram_read_time_ssch_to_irq
	unset histogram_read_time_irq_to_end
	unset histogram_read_ccw_queue_length
}

function print_array()
{
	local width=$1
	shift
	local linebreak=$1
	shift
	local i=1
	for element in $*
	do
		printf "%${width}s" $element
		(( 0 == i++ % linebreak )) && printf "\n"
	done
	# add an extra line break if we do not already have one
	(( 0 != (i - 1) % linebreak )) && printf "\n"
}

function subtract_array()
{
	local -a a=( $1 )
	local -a b=( $2 )
	local -a c
	local i
	local cnt=${#a[@]}
	for (( i = 0 ; i < cnt ; i++ ))
	do
		(( c[i] = a[i] - b[i] ))
	done
	echo -n ${c[*]}
}

function print_line()
{
	local i
	for (( i = 0 ; i < $1 ; i++ ))
	do
		echo -n '-'
	done
	echo
}

HEADERSEXP=" __<4    ___8    __16    __32    __64    _128    _256    _512 \
             __1k    __2k    __4k    __8k    _16k    _32k    _64k    128k \
             _256    _512    __1M    __2M    __4M    __8M    _16M    _32M \
             _64M    128M    256M    512M    __1G    __2G    __4G    _>4G"

HEADERSLIN=" ___0    ___1    ___2    ___3    ___4    ___5    ___6    ___7 \
             ___8    ___9    __10    __11    __12    __13    __14    __15 \
             __16    __17    __18    __19    __20    __21    __22    __23 \
             __24    __25    __26    __27    __28    __29    __30    __31"


function print_format_standard()
{
	local converted_time=$(date -d @$start_time)
	# all numbers in the histograms below are smaller or equal to the
	# total_requests. So we use that number to determine the column width.
	local width=${#total_requests}
	(( width++ ))
	(( width < 5 )) && width=5

	if [[ -n $COLUMN_WIDTH ]] && [[ $width -lt $COLUMN_WIDTH ]]
	then
		width=$COLUMN_WIDTH
	fi

	local linebreak=$NUMBER_COLUMNS
	local statname="$1"
	local tablewidth
	(( tablewidth = width * linebreak ))

	# Note: This function does not print the histogram_io_times_weighted
	#       and histogram_time_ssch_to_irq_weighted because the interpretation
	#       of these histograms is not intuitive and may lead to confusion.
	print_line $tablewidth
	printf "statistics data for statistic: %s\n" "$statname"
	printf "start time of data collection: %s\n\n" "$converted_time"

	printf "%d dasd I/O requests\n" ${total_requests[*]}
	printf "with %u sectors(512B each)\n" ${total_sectors[*]}
	printf "%d requests used a PAV alias device\n" ${total_pav[*]}
	printf "%d requests used HPF\n" ${total_hpf[*]}
	print_array $width $linebreak $HEADERSEXP
	printf "Histogram of sizes (512B secs)\n"
	print_array $width $linebreak ${histogram_sectors[*]}
	printf "Histogram of I/O times (microseconds)\n"
	print_array $width $linebreak ${histogram_io_times[*]}
	printf "Histogram of I/O time till ssch\n"
	print_array $width $linebreak ${histogram_time_build_to_ssch[*]}
	printf "Histogram of I/O time between ssch and irq\n"
	print_array $width $linebreak ${histogram_time_ssch_to_irq[*]}
	printf "Histogram of I/O time between irq and end\n"
	print_array $width $linebreak ${histogram_time_irq_to_end[*]}
	printf "# of req in chanq at enqueuing (0..31) \n"
	print_array $width $linebreak $HEADERSLIN
	print_array $width $linebreak ${histogram_ccw_queue_length[*]}

	if [[ $OUTPUT == "short" ]]
	then
		print_line $tablewidth
		return
	fi

	printf "\n%d dasd I/O read requests\n" ${total_read_requests[*]}
	printf "with %u sectors(512B each)\n" ${total_read_sectors[*]}
	printf "%d requests used a PAV alias device\n" ${total_read_pav[*]}
	printf "%d requests used HPF\n" ${total_read_hpf[*]}
	print_array $width $linebreak $HEADERSEXP
	printf "Histogram of sizes (512B secs)\n"
	print_array $width $linebreak ${histogram_read_sectors[*]}
	printf "Histogram of I/O times (microseconds)\n"
	print_array $width $linebreak ${histogram_read_times[*]}
	printf "Histogram of I/O time till ssch\n"
	print_array $width $linebreak ${histogram_read_time_build_to_ssch[*]}
	printf "Histogram of I/O time between ssch and irq\n"
	print_array $width $linebreak ${histogram_read_time_ssch_to_irq[*]}
	printf "Histogram of I/O time between irq and end\n"
	print_array $width $linebreak ${histogram_read_time_irq_to_end[*]}
	printf "# of req in chanq at enqueuing (0..31) \n"
	print_array $width $linebreak $HEADERSLIN
	print_array $width $linebreak ${histogram_read_ccw_queue_length[*]}

	printf "\n%d dasd I/O write requests\n" $(( total_requests[0] - total_read_requests[0] ))
	printf "with %u sectors(512B each)\n" $(( total_sectors[0] - total_read_sectors[0] ))
	printf "%d requests used a PAV alias device\n" $(( total_pav[0] - total_read_pav[0] ))
	printf "%d requests used HPF\n" $(( total_hpf[0] - total_read_hpf[0] ))
	print_array $width $linebreak $HEADERSEXP
	printf "Histogram of sizes (512B secs)\n"
	print_array $width $linebreak $(subtract_array "${histogram_sectors[*]}" "${histogram_read_sectors[*]}")
	printf "Histogram of I/O times (microseconds)\n"
	print_array $width $linebreak $(subtract_array "${histogram_io_times[*]}" "${histogram_read_times[*]}")
	printf "Histogram of I/O time till ssch\n"
	print_array $width $linebreak $(subtract_array "${histogram_time_build_to_ssch[*]}" "${histogram_read_time_build_to_ssch[*]}")
	printf "Histogram of I/O time between ssch and irq\n"
	print_array $width $linebreak $(subtract_array "${histogram_time_ssch_to_irq[*]}" "${histogram_read_time_ssch_to_irq[*]}")
	printf "Histogram of I/O time between irq and end\n"
	print_array $width $linebreak $(subtract_array "${histogram_time_irq_to_end[*]}" "${histogram_read_time_irq_to_end[*]}")
	printf "# of req in chanq at enqueuing (0..31) \n"
	print_array $width $linebreak $HEADERSLIN
	print_array $width $linebreak $(subtract_array "${histogram_ccw_queue_length[*]}" "${histogram_read_ccw_queue_length[*]}")

	print_line $tablewidth
}

function read_stat_data() {
	local file="$1"

	while read -d ' ' token
	do
		read -a $token
	done < <(cat $file) #avoid inconsistent data due to multiple reads/seeks

	# differentiate I/O error from disabled statistic
	if [[ -n $total_requests ]] || [[ "$token" == "disabled" ]]
	then
		return 0
	else
		return 1
	fi
}

function print_stat() {
	myfile="$1"
	if [[ ! -f "$myfile" ]]
	then
		print_line 80
		echo "$CMD: Statistic \"$myfile\" does not exist" >&2
		print_line 80
		echo
		return
	fi
	unset_known_variables
	if read_stat_data "$myfile"
	then
		if [[ -z "$total_requests" ]]
		then
			if [[ "$VERBOSE" == "true" ]]
			then
				print_line 80
				echo "statistics \"$f\" are disabled"
				print_line 80
				echo
			fi
		else
			print_format_standard $f
			echo
		fi
	else
		print_line 80
		echo "$CMD: Could not read statistic \"$myfile\" " >&2
		print_line 80
		echo
	fi
}

function enable_stat() {
	myfile="$1"
	if [[ ! -f "$myfile" ]]
	then
		echo "$CMD: Statistic \"$myfile\" does not exist" >&2
		return
	fi
	if echo on > "$myfile"
	then
		echo "enable statistic \"$myfile\""
	else
		echo "$CMD: Failed to enable statistic \"$myfile\"" >&2
	fi
}

function disable_stat() {
	myfile="$1"
	if [[ ! -f "$myfile" ]]
	then
		echo "$CMD: Statistic \"$myfile\" does not exist" >&2
		return
	fi
	if echo off > "$myfile"
	then
		echo "disable statistic \"$myfile\""
	else
		echo "$CMD: Failed to disable statistic \"$myfile\""
	fi
}

function reset_stat() {
	myfile="$1"
	if [[ ! -f "$myfile" ]]
	then
		echo "$CMD: Statistic \"$myfile\" does not exist" >&2
		return
	fi
	if echo reset > "$myfile"
	then
		echo "reset statistic \"$myfile\""
	else
		echo "$CMD: Failed to reset statistic \"$myfile\"" >&2
	fi
}

function verbose_msg() {
	if [[ "$VERBOSE" == "true" ]]
	then
		echo "$*"
	fi
}


# Evaluating command line options
CMD=$(basename $0)
DASD_STATISTICS_DIR=""
ALLFILES=""
VERBOSE=false
OUTPUT="short"
NUMBER_COLUMNS=16
COLUMN_WIDTH=
ACTION="print"
while [ $# -gt 0 ]; do
	case $1 in
	--help|-h)
		print_usage
		exit 0
		;;
	--enable|-e)
		ACTION="enable"
		;;
	--disable|-d)
		ACTION="disable"
		;;
	--reset|-r)
		ACTION="reset"
		;;
	--directory|-i)
		DASD_STATISTICS_DIR="$2"
		shift
		if [[ ! -d $DASD_STATISTICS_DIR ]]
		then
			echo "$CMD: $DASD_STATISTICS_DIR is not a directory" >&2
			exit 1
		fi
		;;
	--long|-l)
		OUTPUT="extended"
		;;
	--columns|-c)
		NUMBER_COLUMNS="$2"
		if [[ ! "$NUMBER_COLUMNS" -gt 0 ]]
		then
			echo "$CMD: $NUMBER_COLUMNS is not a positive integer number" >&2
			exit 1
		fi
		shift
		;;
	--column-width|-w)
		COLUMN_WIDTH="$2"
		if [[ ! "$COLUMN_WIDTH" -gt 0 ]]
		then
			echo "$CMD: $COLUMN_WIDTH is not a positive integer number" >&2
			exit 1
		fi
		shift
		;;
	--verbose|-V)
		VERBOSE=true
		;;
	--version|-v)
		print_version
		exit 0
		;;
	-*)
		echo "$CMD: Invalid option $1" >&2
		echo "Try '$CMD --help' for more information." >&2
		exit 1
		;;
	*)
		ALLFILES="$ALLFILES $1"
		;;
	esac
	shift
done

# if no directory is given on command line, find dasd directory in debugfs
if [[ "$DASD_STATISTICS_DIR" == "" ]]
then
	while read -a mntentries
	do
		if [[ "${mntentries[2]}" == "debugfs" ]]
		then
			DASD_STATISTICS_DIR="${mntentries[1]}"
			verbose_msg "found debugfs mount point $DASD_STATISTICS_DIR"
			break;
		fi
	done < /etc/mtab
	if [[ "$DASD_STATISTICS_DIR" == "" ]]
	then
		echo "$CMD: No debugfs mount point found" >&2
		exit 1
	fi
	DASD_STATISTICS_DIR="$DASD_STATISTICS_DIR/dasd"
	if [[ ! -d "$DASD_STATISTICS_DIR" ]]
	then
		echo "$CMD: Default DASD debugfs directory $DASD_STATISTICS_DIR does not exist" >&2
		exit 1
	fi
fi

# look for directories that contain statistics
if [[ "$ALLFILES" == "" ]]
then
	ALLFILES=$(ls -x $DASD_STATISTICS_DIR)
	explicitstats="false"
else
	explicitstats="true"
fi
ALLSTATS=""
for f in $ALLFILES
do
	if [[ -f "$DASD_STATISTICS_DIR/$f/statistics" ]]
	then
		ALLSTATS="$ALLSTATS $f"
	elif [[ $explicitstats == "true" ]]
	then
		echo "$CMD: No statistics found for $f" >&2
	fi
done

verbose_msg "found the following statistics in directory $DASD_STATISTICS_DIR:"
verbose_msg "$ALLSTATS"

# execute the required operation
for f in $ALLSTATS
do
	case $ACTION in
	"enable")
		enable_stat "$DASD_STATISTICS_DIR/$f/statistics"
		;;
	"disable")
		disable_stat "$DASD_STATISTICS_DIR/$f/statistics"
		;;
	"reset")
		reset_stat "$DASD_STATISTICS_DIR/$f/statistics"
		;;
	"print")
		print_stat "$DASD_STATISTICS_DIR/$f/statistics"
		;;
	*)
		echo "error"
		exit 1
		;;
	esac
done