#!/bin/sh

#
# Copyright (c) 2016 SUSE LINUX GmbH, Nuernberg, Germany.
# Released under the GNU General Public License version 2.
#

let FORCE=0
DEVPARM=""

usage(){
  echo "Usage: ${0} [ -f ] devno|busid"
  echo "	-f	Force unformatting for DASD volumes in the CMS device range of 19x."
  echo "	devno	The \"plain\" device number of the volume, e.g. 3184."
  echo "	busid	The full specification of the volume, e.g., 0.0.3184."
}

ARCH="$(/usr/bin/uname -m)"
if [ "${ARCH}" != "s390x" ] && [ "${ARCH}" != "s390" ]; then
  echo "This script is only useful on IBM mainframes."
  exit 1
fi

############################################################
# Parse the parameters from the command line
#
ARGS=$(getopt -a --options f -n "killcdl" -- "$@")
if [ $? -ne 0 ]; then
  usage
  exit 3
fi

eval set -- "${ARGS}"
for ARG; do
	case "${ARG}" in
		-f) FORCE=1
		    shift 1
		    ;;
		--) shift 1
		    ;;
		[0-9a-fA-F]*) if [ ! -z "${DEVPARM}" ]; then
				echo "More than one parameter specified."
				usage
				exit 4
			      fi
			      DEVPARM=${1}
			      shift 1
			      ;;
		*) echo "That looks invalid"
		   usage
		   exit 5
		   ;;
        esac
done

if [ -z "${DEVPARM}" ]; then
  echo "You must specify the device number of the DASD volume to be unformatted."
  usage
  exit 6
fi

DEVNO=$(echo "${DEVPARM}" | tr A-Z a-z)

# Validate the device number or busid provided
set -- $(IFS='.'; echo ${DEVNO})
let NUMPARMS=${#}
if [ ${NUMPARMS} -ne 1 ] && [ ${NUMPARMS} -ne 3 ]; then
  echo "You have not specified the device number in a recognizable format."
  echo "It must either be the plain device number, e.g., 0123, or in"
  echo "so-called busid format, e.g., 0.0.0123"
  exit 7
fi

# Just a device number, SIMPLE=1. A busid, SIMPLE=0
SIMPLE=0
if [ ${NUMPARMS} -eq 1 ]; then
  let SIMPLE=1
  let FIRST=0
  let FIRSTLEN=1
  let SECOND=0
  let SECONDLEN=1
  DEVNO="${1}"
  let DEVNOLEN=${#1}
else FIRST="${1}"
     let FIRSTLEN=${#FIRST}
     SECOND="${2}"
     let SECONDLEN=${#SECOND}
     DEVNO="${3}"
     let DEVNOLEN=${#3}
fi

if [ ${FIRSTLEN} -ne 1 ] || [ ${SECONDLEN} -ne 1 ]; then
  echo "The first and second fields of the busid may only be one digit long."
  exit 8
fi

if [ ${DEVNOLEN} -gt 4 ]; then
  echo "The device number may only be 4 digits long."
  exit 9
fi

if [ ${DEVNOLEN} -lt 4 ]; then
  DEVNO=$(echo "0000${DEVNO}" | rev | cut -c1-4 | rev)
fi

BUSID="${FIRST}.${SECOND}.${DEVNO}"

if [ ! -h /sys/bus/ccw/devices/${BUSID} ]; then
  echo "Busid ${BUSID} was not found."
  /usr/sbin/cio_ignore -i ${BUSID} > /dev/null
  if [ $? -eq 0 ]; then
    echo "That device is in the cio_ignore list."
    echo "Please remove it with \"cio_ignore -r ${BUSID}\" before trying again."
  fi
  exit 10
fi

case ${DEVNO:0:3} in
	019)	if grep -q "version = FF" /proc/cpuinfo 2>/dev/null; then
		  echo "That looks like a CMS disk."
		  if [ ${FORCE} -eq 0 ]; then
		    echo "Specify the -f option to force the operation."
		    exit 11
		  fi
		  echo "But you specified -f so we'll kill it anyway."
		fi
		;;
esac

read ORIG_ONLINE_STATUS < /sys/bus/ccw/devices/${BUSID}/online

DISCIPLINE="none"
if [ -r /sys/bus/ccw/devices/${BUSID}/discipline ]; then
  # We have to bring the device online before the kernel will fill in
  # the value for discipline.
  if [ ${ORIG_ONLINE_STATUS} -eq 0 ]; then
    /usr/sbin/chccwdev -e ${BUSID}
    /usr/sbin/udevadm settle
  fi

  read STATUS < /sys/bus/ccw/devices/${BUSID}/status
  if [ "${STATUS}" == "unformatted" ]; then
    echo "DASD device ${BUSID} is already in an unformatted state."
    if [ ${ORIG_ONLINE_STATUS} -eq 0 ]; then
      /usr/sbin/chccwdev -d -s ${BUSID}
      /usr/sbin/udevadm settle
    fi
    exit 0
  fi

  read DISCIPLINE < /sys/bus/ccw/devices/${BUSID}/discipline 
else read CU_TYPE < /sys/bus/ccw/devices/${BUSID}/cutype
     read DEV_TYPE < /sys/bus/ccw/devices/${BUSID}/devtype
     case "${CU_TYPE}" in
	3990/*|2105/*|2107/*|1750/*|9343/*)
		DISCIPLINE=ECKD
		;;
	3880/*)
		case "${DEV_TYPE}" in
			3390/*)
				DISCIPLINE=ECKD
				;;
		esac
		;;
     esac
fi

if [ "${DISCIPLINE}" != "ECKD" ]; then
  echo "This script only works on ECKD DASD."
  if [ ${ORIG_ONLINE_STATUS} -eq 0 ]; then
    /usr/sbin/chccwdev -d -s ${BUSID}
  fi
  exit 12
fi

read STATUS < /sys/bus/ccw/devices/${BUSID}/online
if [ ${STATUS} -eq 1 ]; then
  if [ ! -h /dev/disk/by-path/ccw-${BUSID} ]; then
    echo "The udev-generated symbolic link in /dev/disk/by-path was not found."
    exit 13
  fi

  /usr/sbin/chccwdev -d -s ${BUSID}
  /usr/sbin/udevadm settle

  read STATUS < /sys/bus/ccw/devices/${BUSID}/online
  if [ ${STATUS} -ne 0 ]; then
    echo "Device number ${DEVNO} didn't go offline. Unable to continue."
    exit 14
  fi
fi

/usr/sbin/chccwdev -a raw_track_access=1 -e ${BUSID}
/usr/sbin/udevadm settle

read STATUS < /sys/bus/ccw/devices/${BUSID}/online
if [ ${STATUS} -ne 1 ]; then
  echo "Unable to bring ${DEVNO} online. Unable to continue."
  exit 15
fi

# After this point, we will kill the formatting on the device
perl -e 'for ($h=0;$h<2;$h++){printf "\0\0\0%c\0\0\0\x8%s",$h,(("\0"x8).("\xff"x8).("\0"x65512))}' | dd bs=65536 count=2 oflag=direct of=/dev/disk/by-path/ccw-${BUSID} >/dev/null 2>&1

if [ "$?" -ne 0 ]; then
  echo "The writing of the null record 0 failed."
  exit 16
fi

echo "Setting ${BUSID} back offline with raw track access disabled."
/usr/sbin/chccwdev -d -s -a raw_track_access=0 ${BUSID}
/usr/sbin/udevadm settle

if [ ${ORIG_ONLINE_STATUS} -eq 1 ]; then
  /usr/sbin/chccwdev -e ${BUSID}
  /usr/sbin/udevadm settle
fi