#!/bin/bash

WIPE_UNIT=./unit-wipe
FILE=./wipe_localfile
FILE_RAND=./wipe_random_localfile
MB_BYTES=$((1024*1024))
DEVSIZEMB=8
DEVSIZE=$((DEVSIZEMB*$MB_BYTES))

HASH_EMPTY=2daeb1f36095b44b318410b3f4e8b5d989dcc7bb023d1426c492dab0a3053e74

function cleanup() {
	rm -f $FILE $FILE_RAND 2> /dev/null
	sleep 1
	rmmod scsi_debug >/dev/null 2>&1
}

function fail()
{
	if [ -n "$1" ] ; then echo "FAIL $1" ; else echo "FAIL" ; fi
	echo "FAILED backtrace:"
	while caller $frame; do ((frame++)); done
	cleanup
	exit 100
}

function skip()
{
	echo "TEST SKIPPED: $1"
	cleanup
	exit 77
}

function add_device()
{
	rmmod scsi_debug >/dev/null 2>&1
	if [ -d /sys/module/scsi_debug ] ; then
		skip "Cannot use scsi_debug module (in use or compiled-in)."
	fi
	modprobe scsi_debug dev_size_mb=$DEVSIZEMB num_tgts=1 delay=0 >/dev/null 2>&1
	if [ $? -ne 0 ] ; then
		skip "This kernel seems to not support proper scsi_debug module."
	fi
	grep -q scsi_debug /sys/block/*/device/model || sleep 2
	DEV=$(grep -l -e scsi_debug /sys/block/*/device/model | cut -f4 -d /)
	DEV="/dev/$DEV"
	[ -b $DEV ] || fail "Cannot find $DEV."
}

function check_hash() # $1 dev, $2 hash
{
	local HASH=$(sha256sum $1 | cut -d' ' -f 1)
	[ $HASH == "$2" ]
}

function init_hash_dd() # $1 dev, $dev orig
{
	dd if=/dev/urandom of=$2 bs=1M count=$DEVSIZEMB conv=notrunc 2> /dev/null
	dd if=$2 of=$1 bs=1M conv=notrunc 2> /dev/null
	HASH_0=$(sha256sum $1 | cut -d' ' -f 1)
	# second MB wiped
	dd if=/dev/zero of=$1 bs=1M seek=1 count=1 conv=notrunc 2> /dev/null
	HASH_1=$(sha256sum $1 | cut -d' ' -f 1)
	# 4,5,6 MB wiped
	dd if=/dev/zero of=$1 bs=1M seek=4 count=3 conv=notrunc 2> /dev/null
	HASH_2=$(sha256sum $1 | cut -d' ' -f 1)
	dd if=$2 of=$1 bs=1M conv=notrunc 2> /dev/null
}

function add_file()
{
	dd if=/dev/zero of=$FILE      bs=1M count=$DEVSIZEMB 2> /dev/null || fail
	dd if=/dev/zero of=$FILE_RAND bs=1M count=$DEVSIZEMB 2> /dev/null || fail
	check_hash $FILE $HASH_EMPTY || fail
	check_hash $FILE_RAND $HASH_EMPTY || fail
	dd if=$FILE of=/dev/null bs=4096 count=1 iflag=direct >/dev/null 2>&1 || FILE_NODIO=1
}

function test_wipe_full() # $1 dev, $2 block size, [$3 flags]
{
	# wipe random and back to zero
	$WIPE_UNIT $1 random 0 $DEVSIZE $2 $3 || fail
	check_hash $1 $HASH_EMPTY && fail "Failed random wipe"
	$WIPE_UNIT $1 zero 0 $DEVSIZE $2 $3 || fail
	check_hash $1 $HASH_EMPTY || fail "Failed zero wipe"
}

# wipe MB blocks, with zero, random and special and back to original
function test_wipe_blocks() # $1 dev $2 block sizem [$3 flags]
{
	init_hash_dd $1 $FILE_RAND
	check_hash $1 $HASH_0 || fail

	$WIPE_UNIT $1 zero    $((1*$MB_BYTES)) $((1*$MB_BYTES)) $2 $3 || fail
	check_hash $1 $HASH_1 || fail
	$WIPE_UNIT $1 random  $((1*$MB_BYTES)) $((1*$MB_BYTES)) $2 $3 || fail
	check_hash $1 $HASH_1 && fail
	$WIPE_UNIT $1 special $((1*$MB_BYTES)) $((1*$MB_BYTES)) $2 $3 || fail
	check_hash $1 $HASH_1 && fail
	$WIPE_UNIT $1 zero    $((1*$MB_BYTES)) $((1*$MB_BYTES)) $2 $3 || fail
	check_hash $1 $HASH_1 || fail

	$WIPE_UNIT $1 zero    $((4*$MB_BYTES)) $((3*$MB_BYTES)) $2 $3 || fail
	check_hash $1 $HASH_2 || fail
	$WIPE_UNIT $1 random  $((4*$MB_BYTES)) $((3*$MB_BYTES)) $2 $3 || fail
	check_hash $1 $HASH_2 && fail
	$WIPE_UNIT $1 special $((4*$MB_BYTES)) $((3*$MB_BYTES)) $2 $3 || fail
	check_hash $1 $HASH_2 && fail
	$WIPE_UNIT $1 zero    $((4*$MB_BYTES)) $((3*$MB_BYTES)) $2 $3 || fail
	check_hash $1 $HASH_2 || fail
}

test -x $WIPE_UNIT || skip "Run \"make `basename $WIPE_UNIT`\" first"

cleanup
add_file

echo -n "[1] Wipe full file "
for bs in 0 $MB_BYTES $((4*$MB_BYTES)); do
	if [ -n "$FILE_NODIO" ]; then
		echo -n [$bs/DIO N/A]
	else
		echo -n [$bs/DIO]
		test_wipe_full $FILE $bs
	fi
	echo -n [$bs]
	test_wipe_full $FILE $bs no-dio
done
echo "[OK]"

echo -n "[2] Wipe blocks in file "
for bs in 0 $MB_BYTES $((4*$MB_BYTES)); do
	if [ -n "$FILE_NODIO" ]; then
		echo -n [$bs/DIO N/A]
	else
		echo -n [$bs/DIO]
		test_wipe_blocks $FILE $bs
	fi
	echo -n [$bs]
	test_wipe_blocks $FILE $bs no-dio
done
echo "[OK]"

[ $(id -u) -eq 0 ] || {
	echo "WARNING: You must be root to run remaining tests."
	cleanup
	exit 0
}

add_device

echo -n "[3] Wipe full block device "
for bs in 0 $MB_BYTES $((4*$MB_BYTES)); do
	echo -n [$bs/DIO]
	test_wipe_full $DEV $bs
	echo -n [$bs]
	test_wipe_full $DEV $bs no-dio
done
echo "[OK]"

echo -n "[4] Wipe blocks in block device "
for bs in 0 $MB_BYTES $((4*$MB_BYTES)); do
	echo -n [$bs/DIO]
	test_wipe_blocks $DEV $bs
	echo -n [$bs]
	test_wipe_blocks $DEV $bs no-dio
done
echo "[OK]"

cleanup