#!/bin/bash
#
# /bin/sh isn't always compatible so use /bin/bash
#
# Bacula interface to mtx autoloader
#
#  $Id$
#
#  If you set in your Device resource
#
#  Changer Command = "path-to-this-script/mtx-changer  %c %o %S %a %d"
#    you will have the following input to this script:
#
#  mtx-changer "changer-device" "command" "slot" "archive-device" "drive-index"
#                  $1              $2       $3        $4               $5
#
#  for example:
#
#  mtx-changer /dev/sg0 load 1 /dev/nst0 0 (on a Linux system)
#
#  If you need to an offline, refer to the drive as $4
#    e.g.   mt -f $4 offline
#
#  Many changers need an offline after the unload. Also many
#   changers need a sleep 60 after the mtx load.
#
#  N.B. If you change the script, take care to return either 
#   the mtx exit code or a 0. If the script exits with a non-zero
#   exit code, Bacula will assume the request failed.
#

# Sun sed/awk etc are not sufficient, working versions are in /usr/xpg4/bin
export PATH="/usr/local/bin:/usr/sfw/bin:/usr/xpg4/bin:/usr/bin"

MTX=mtx

TMPDIR=/tmp

make_temp_file() 
{
  TMPFILE=`mktemp ${TMPDIR}/mtx$1.XXXXXXXXXX 2> /dev/null`
  if test $? -ne 0 || test x${TMPFILE} = x; then
     TMPFILE="${TMPDIR}/mtx$1.$$"
     if test -f ${TMPFILE}; then
        echo "ERROR: Temp file security problem on: ${TMPFILE}"
        exit 1
     fi
  fi
}




#
# The purpose of this function to wait a maximum 
#   time for the drive. It will
#   return as soon as the drive is ready, or after
#   waiting a maximum of 180 seconds.
# Note, this is very system dependent, so if you are
#   not running on Linux, you will probably need to
#   re-write it.
#
# If you have a FreeBSD system, you might want to change
#  the $(seq 180) to $(jot 180) -- tip from Brian McDonald
#
wait_for_drive() {
  for i in $(seq 180); do   # Wait max 180 seconds
    if ( mt -f $1 status | grep 0x0 ) >/dev/null 2>&1; then
      #echo "Device $1 READY"
      break
    fi
    #echo "Device $1 - not ready, retry ${i}..."
    sleep 1
  done
}


if test $# -lt 2 ; then
  echo "usage: mtx-changer ctl-device command slot archive-device drive"
  echo "  Insufficient number of arguments arguments given."
  echo "  Mimimum usage is first two arguments ..."
  exit 1
fi

# Setup arguments
ctl=$1
cmd="$2"
slot=$3
device=$4
# If drive not given, default to 0
if test $# = 5 ; then
  drive=$5
else
  drive=0
fi

#
# Check for special cases where only 2 arguments are needed, 
#  all others are a minimum of 3
case $cmd in
   loaded)
     ;;
   unload)
     ;;
   list)
     ;;
   slots)
     ;;
   *)
     if test $# -lt 3; then
        echo "usage: mtx-changer ctl-device command slot archive-device drive"
        echo "  Insufficient number of arguments arguments given."
        echo "  Mimimum usage is first three arguments ..."
        exit 1
     fi
     ;;
esac


case $cmd in 
   unload)
#     echo "Doing mtx -f $ctl unload $slot $drive"
#
# enable the following line if you need to eject the cartridge
      #mt -f $device offline
      mt -f $device rewoffl
      if test x$slot = x; then
         ${MTX} -f $ctl unload
      else
         ${MTX} -f $ctl unload $slot $drive
      fi
      ;;

   load)
#     echo "Doing mtx -f $ctl load $slot $drive"
      ${MTX} -f $ctl load $slot $drive
      rtn=$?
#
# Increase the sleep time if you have a slow device
# or remove the sleep and add the following:
      #sleep 15
      wait_for_drive $device
      exit $rtn
      ;;

   list) 
#     echo "Requested list"
      # Some tape changers lose track of their inventory (well, mine does) so 
      # do one before trying to get a status out of it.
      ${MTX} -f $ctl inventory
      ${MTX} -f $ctl status | grep " *Storage Element [0-9]*:.*Full" | awk "{print \$3 \$4}" | sed "s/Full *\(:VolumeTag=\)*//"
# Comment out the previous line and add a line here
# to print "fake" barcodes.
#
# If you have a VXA PacketLoader and the above does not work, try
#  turning it off and enabling the following line.
#     ${MTX} -f $ctl status | grep " *Storage Element [0-9]*:.*Full" | sed "s/*Storage Element //" | sed "s/Full :VolumeTag=//"
      ;;

   loaded)
      make_temp_file
      ${MTX} -f $ctl status >${TMPFILE}
      rtn=$?
      cat ${TMPFILE} | grep "^Data Transfer Element $drive:Full" | awk "{print \$7}"
      cat ${TMPFILE} | grep "^Data Transfer Element $drive:Empty" | awk "{print 0}"
      rm -f ${TMPFILE}
      exit $rtn
      ;;

   slots)
#     echo "Request slots"
      ${MTX} -f $ctl status | grep " *Storage Changer" | awk "{print \$5}"
      ;;
esac