#!/bin/bash
#set -x
#
# block-iscsimple - 2014-07-01-000 - Thierry Jaouen <thierry@tjaouen.fr>
#
# Based on: block-iscsi - 2009 Keith Herron <keith@backdrift.org>
#
# Simple iscsi connector for Xen :
#   - Faster
#   - No multipath (I don't known what it is)
#   - Accept different "Lun" (see syntax below)
#   - login/logout only when necessary
#
# Note: This script does NOT depends on a block-iscsimple.conf file
#       located in the same directory.
#       This optionnal file contains an array of available iSCSI target IPs
#
# Syntaxe:
# Only iscsi:
#   iscsimple:{lunX@}iqn.....
# With Raid-1 support:
#   iscsimple:{lunX@}iqn+<NAME>
#
# <NAME> is define in the file block-iscsimple-tab.conf 
#   <NAME> <DEVICE>
#
# Examples:
#   iscsimple:iqn.2014-06.fr.thierry-jaouen:share-sn-0001+test_raid
#
#  In the "block-iscsimple-tab.conf" file, you have got:
#   test_raid     /dev/vg0/my-disk
#

NAME=$( basename "$0" )

dir=$(dirname "$0")

. "$dir/block-common.sh"

# Log which mode we are in
logger -t "$NAME" "*** Beginning device ${command} ***"

# Fetch the param we specify in the domu config file

PARAMS=`xenstore_read "${XENBUS_PATH}/params"`

# This is a RAID1 "LABEL" ?
RAID1_NAME=$( echo "${PARAMS}" | sed -n -e 's/^.\++\([-_0-9a-zA-Z]\+\)$/\1/Ip' )

if [ -n "${RAID1_NAME}" ]; then
  # NAME+IQN

  TAB_FILE="$dir/$NAME-tab.conf"

  if [ ! -r "${TAB_FILE}" ] ; then
    logger -t "$NAME" "File ${TAB_FILE} required."
  fi

  # Check for mdadm
  if ! [ -x "$( which mdadm )" ]; then
    logger -t "$NAME" "No mdadm utility - install mdadm for RAID-1 support."
    exit 1
  fi

  ISCSI_PARAM=$( echo "${PARAMS}" | awk -F'+' '{ print $1 }' )

  DEVICE_PARAM=$( awk -F' ' '/^'"${RAID1_NAME}"'\s+/ { print $2 }' "${TAB_FILE}" | head -1 )

  if [ -z "${DEVICE_PARAM}" ]; then
    logger -t "$NAME" "No device found in ${TAB_FILE}"
  fi

  if [ -z "${ISCSI_PARAM}" ] || [[ "${ISCSI_PARAM}" = MISSING* ]]; then
    # No ISCSI drive
    ISCSI_PARAM=''
  fi
  if [[ "${DEVICE_PARAM}" = MISSING* ]]; then
    # No local device
    DEVICE_PARAM=''
  fi
  if [ -z "${ISCSI_PARAM}" ] && [ -z "${DEVICE_PARAM}" ]; then
    logger -t "$NAME" "No drive for starting RAID-1"
    exit 1
  fi

else
  # IQN simple
  ISCSI_PARAM="${PARAMS}"
fi

if [ -n "${ISCSI_PARAM}" ]; then

  # Check for iscsiadm
  if ! [ -x "$( which iscsiadm )" ]; then
    logger -t "$NAME" "No iscsiadm utility - install open-iscsi."
    exit 1
  fi

  if [ -r "$dir/${NAME}.conf" ]; then
    . "$dir/${NAME}.conf"
  
    # We define portal IP in order to support new luns which don't yet have
    # /var/lib/iscsi/node entrys yet, not dynamic but avoids manual discovery 
    #
  
    for PORTAL in ${PORTALS[@]}; do
      logger -t "$NAME" `iscsiadm -m discovery -t st -p "${PORTAL}"`
    done
  fi

  # ISCSI_PARAM=IQN.... or ISCSI_PARAM=LunXXX@IQN....
  # Example: iqn.2014-06.fr.thierry-jaouen:partage1-sn-1234
  #          Lun0@iqn.2014-06.fr.thierry-jaouen:partage1-sn-1234
  
  # If exists, extract "Lun" number
  
  IQN_LUN=$( echo "$ISCSI_PARAM" | sed -n -e 's/^lun\([0-9]\+\)@iqn\..\+$/\1/Ip' )
  
  if [ -n "$IQN_LUN" ]; then
    IQN=$( echo "$ISCSI_PARAM" | sed -n -e 's/^lun[0-9]\+@\(iqn\..\+\)$/\1/Ip' )
  else
    IQN_LUN="0"
    IQN=$ISCSI_PARAM
  fi
  
fi

if [ -n "${RAID1_NAME}" ]; then
  logger -t "$NAME" "RAID1:${RAID1_NAME} IQN:${IQN} LUN:${IQN_LUN} DEVICE:${DEVICE_PARAM}"
else
  logger -t "$NAME" "IQN:${IQN} LUN:${IQN_LUN}"
fi

if [ -n "${ISCSI_PARAM}" ]; then
  # Using the iscsi node directory we can determine the ip and port of 
  # our iscsi target on a lun by lun basis
  #
  [ -d /var/lib/iscsi/nodes ] && NODES_DIR=/var/lib/iscsi/nodes
  [ -d /etc/iscsi/nodes ] && NODES_DIR=/etc/iscsi/nodes
  
  if [ -z "${NODES_DIR}" ]; then
    logger -t "$NAME" "Do not know where iscsi node directory is located"
    exit 1
  fi
  
  if IPPORT=$( ls "${NODES_DIR}/${IQN}/" ) ; then
    IP=$( echo "${IPPORT}" | cut -d , -f 1 )
    PORT=$( echo "${IPPORT}" | cut -d , -f 2 )
  fi
  
  if [ -z "${IP}" ] || [ -z "${PORT}" ]; then
    logger -t "$NAME" "iscsi node not found. Try 'discovery' with iscsiadm"
    exit 1
  fi
  
  logger -t "$NAME" "TARGET: ${IP}:${PORT}"
fi

# -----------------------------------------------------

# This is called by each command to determine which device to use
#

function guess_md_dev
{
  MD_DEV=''

  if MD_DEV=$( readlink --canonicalize-existing "/dev/md/${RAID1_NAME}" ) ; then
    if [ -e "${MD_DEV}" ]; then
      logger -t "$NAME" "md device: ${MD_DEV}"
    else
      MD_DEV=''
    fi
  fi
}

function assemble_md
{
  MD_DEV_PREEXIST=1
  guess_md_dev

  if [ -z "${MD_DEV}" ]; then
    MD_DEV_PREEXIST=0
    if mdadm --quiet --build "/dev/md/${RAID1_NAME}" --level=1 --raid-devices=2 $@ ; then
      guess_md_dev
    fi
  fi
}

function guess_iscsi_dev
{
   # Now we determine which /dev/sd* device belongs to the iqn

   SCSI_DEV=''

   if SCSI_DEV=$( readlink --canonicalize-existing "/dev/disk/by-path/ip-${IP}:${PORT}-iscsi-${IQN}-lun-${IQN_LUN}" ) ; then
     if [ -e "${SCSI_DEV}" ]; then
       logger -t "$NAME" "scsi device: ${SCSI_DEV}"
     else
       SCSI_DEV=''
     fi
   fi
}

function add_iscsi
{
  for i in 0 0.25 0.5 1 0 1 1
  do
    guess_iscsi_dev

    if [ -n "${SCSI_DEV}" ]; then
      logger -t "$NAME" "adding device: ${SCSI_DEV}"
      # keep a list of added device...
      echo "${SCSI_DEV}" >> "${DEVLIST}"
      break
    fi

    if [ "$i" = "0" ]; then
      if RESULT=$( iscsiadm -m node -T "${IQN}" -p "${IP}:${PORT}" --login 2>&1 ) ; then
        echo "$RESULT" | logger -t "$NAME"
        sleep 0.25
      else
        ERR_CODE=$?
        echo "$RESULT" | logger -t "$NAME"
        logger -t "$NAME" "Abort with iscsiadm error: $ERR_CODE"
        break
      fi
    else
      sleep $i
    fi

  done
}

function remove_iscsi
{
  if [ -e "${SCSI_DEV}" ]; then
    logger -t "$NAME" "flushing buffers on ${SCSI_DEV}"
    blockdev --flushbufs "${SCSI_DEV}"

    # remove this device from the list...
    sed -i -e "\%^${SCSI_DEV}\$%d" "${DEVLIST}"

    if [ ! -s "${DEVLIST}" ]; then
      # the list is empty: we can logout
      logger -t "$NAME" "attempting logout of ${IQN} on ${IP}:${PORT}"
      iscsiadm -m node -T "${IQN}" -p "${IP}:${PORT}" --logout 2>&1 | logger -t "$NAME"
      rm -f "${DEVLIST}"
    fi
  fi
}

# -----------------------------------------------------

WORKDIR="/var/run/xen-hotplug/${NAME}/${IQN}"
LOCKFILE="${WORKDIR}/lock"
DEVLIST="${WORKDIR}/dev.list"

[ -d "${WORKDIR}" ] || mkdir -p "${WORKDIR}" >/dev/null 2>&1

lockfile -1 -l 10 -s 0 "${LOCKFILE}" || exit 1

# TRAP --------
trap "rm -f \"${LOCKFILE}\"" 0
# -------------

case $command in

   add)

     if [ -n "${RAID1_NAME}" ]; then

       if [ -n "${ISCSI_PARAM}" ]; then
         # Not "MISSING"...

         # Login to the target
         logger -t "$NAME" "logging in to ${IQN} on ${IP}:${PORT}"
  
         add_iscsi
  
         if [ -n "${SCSI_DEV}" ]; then
           logger -t "$NAME" "md: assemble ..."

           assemble_md "missing" "--write-mostly" "${SCSI_DEV}"

           if [ -n "${MD_DEV}" ]; then
             ERR=0

             if [ $MD_DEV_PREEXIST -ne 0 ] ; then
               logger -t "$NAME" "Device $MD_DEV already create. Continue."
             elif [ -n "${DEVICE_PARAM}" ] ; then
               # Ajouter le disk local
               logger -t "$NAME" "Adding ${DEVICE_PARAM} ..."
	       if ! mdadm --quiet "${MD_DEV}" --add "${DEVICE_PARAM}" ; then
                 ERR=$(( ERR+1 ))
               fi
	     fi

             if [ $ERR -eq 0 ]; then
	       logger -t "$NAME" "$command complete. Dev: ${MD_DEV}"
               write_dev "${MD_DEV}"
               exit 0
             fi

             logger -t "$NAME" "Abort $MD_DEV"

             mdadm --quiet --stop "${MD_DEV}"
           fi

           remove_iscsi

         else 
           logger -t "$NAME" "No device"
         fi

       else
         logger -t "$NAME" "md: assemble ..."

	 assemble_md "${DEVICE_PARAM}" "missing"

         if [ -n "${MD_DEV}" ]; then
           # OK
	   logger -t "$NAME" "$command complete. Dev: ${MD_DEV}"
           write_dev "${MD_DEV}"
           exit 0
         fi

       fi

     else
       # Login to the target
       logger -t "$NAME" "logging in to ${IQN} on ${IP}:${PORT}"
  
       add_iscsi
  
       if [ -n "${SCSI_DEV}" ]; then
	 logger -t "$NAME" "$command complete. Dev: ${SCSI_DEV}"
         write_dev "${SCSI_DEV}"
         exit 0
       else
         logger -t "$NAME" "No device"
       fi
       
     fi

     exit 1
   ;;

   remove)

     if [ -n "${RAID1_NAME}" ]; then
           
       guess_md_dev

       if [ ! -n "${MD_DEV}" ]; then
         logger -t "$NAME" "No device found for ${RAID1_NAME}"
         exit 1
       else
         if mdadm --quiet --stop "${MD_DEV}" ; then
           if [ -n "${ISCSI_PARAM}" ]; then
             guess_iscsi_dev
             remove_iscsi
           fi
         fi
       fi
     else
       guess_iscsi_dev
       remove_iscsi
     fi

   ;;

esac

# -----------------------------------------------------
# EOF