#!/bin/sh
#
# Bacula interface to mtx autoloader
#
#  $Id: mtx-changer.in 5002 2007-06-09 09:25:27Z kerns $
#
#  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:
#
#  So Bacula will always call with all the following arguments, even though
#    in come cases, not all are used.
#
#  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)
# 
#  will request to load the first cartidge into drive 0, where
#   the SCSI control channel is /dev/sg0, and the read/write device
#   is /dev/nst0.
#
#  The commands are:
#      Command		  Function
#      unload		  unload a given slot
#      load		  load a given slot
#      loaded		  which slot is loaded?
#      list		  list Volume names (requires barcode reader)
#      slots		  how many slots total?
#
#  Slots are numbered from 1 ...
#  Drives are numbered from 0 ...
#
#
#  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.
#

MTX=mtx

# mt status output
# SunOS     No Additional Sense
# FreeBSD   Current Driver State: at rest.
# Linux     ONLINE

OS=`uname`
case ${OS} in
  SunOS)
    ready="No Additional Sense"
    ;;
  FreeBSD)
    ready="Current Driver State: at rest."
    ;;
  *)
    ready="ONLINE"
  ;;
esac

#
# log whats done
#
# to turn on logging, uncomment the following line
#touch /var/db/bacula/mtx.log
#
dbgfile="/var/db/bacula/mtx.log"
debug() {
    if test -f $dbgfile; then
	echo "`date +\"%Y%m%d-%H:%M:%S\"` $*" >> $dbgfile
    fi
}


#
# Create a temporary file
#
make_temp_file() {
  TMPFILE=`mktemp /var/db/bacula/mtx.XXXXXXXXXX`
  if test x${TMPFILE} = x; then
     TMPFILE="/var/db/bacula/mtx.$$"
     if test -f ${TMPFILE}; then
	echo "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 300 seconds.
# Note, this is very system dependent, so if you are
#   not running on Linux, you will probably need to
#   re-write it, or at least change the grep target.
#   We've attempted to get the appropriate OS grep targets
#   in the code at the top of this script.
#
wait_for_drive() {
  i=0 
  while [ $i -le 300 ]; do  # Wait max 300 seconds
    if mt -f $1 status | grep ${ready}	>/dev/null 2>&1; then
      break
    fi
    debug "Device $1 - not ready, retrying..."
    sleep 1
    i=`expr $i + 1`
  done
}

# check parameter count on commandline
#
check_parm_count() {
    pCount=$1
    pCountNeed=$2
    if test $pCount -lt $pCountNeed; then
	echo "usage: mtx-changer ctl-device command [slot archive-device drive-index]"
	echo "	Insufficient number of arguments given."
	if test $pCount -lt 2; then
	    echo "  Mimimum usage is first two arguments ..."
	else
	    echo "  Command expected $pCountNeed arguments"
	fi
	exit 1
    fi
}

# Check for special cases where only 2 arguments are needed, 
#  all others are a minimum of 5
#
case $2 in
    list)
	check_parm_count $# 2
	;;
    slots)
	check_parm_count $# 2
	;;
    *)
	check_parm_count $# 5
	;;
esac


# Setup arguments
ctl=$1
cmd="$2"
slot=$3
device=$4
drive=$5

debug "Parms: $ctl $cmd $slot $device $drive"

case $cmd in 
   unload)
      debug "Doing mtx -f $ctl unload $slot $drive"
#
# enable the following line if you need to eject the cartridge
#     mt -f $device offline
#     sleep 10
      ${MTX} -f $ctl unload $slot $drive
      ;;

   load)
      debug "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) 
      debug "Doing mtx -f $ctl -- to list volumes"
      make_temp_file
# Enable the following if you are using barcodes and need an inventory
#     ${MTX} -f $ctl inventory
      ${MTX} -f $ctl status >${TMPFILE}
      rtn=$?
      cat ${TMPFILE} | grep " Storage Element [0-9]*:.*Full" | awk "{print \$3 \$4}" | sed "s/Full *\(:VolumeTag=\)*//"
#
# If you have a VXA PacketLoader and the above does not work, try
#  turning it off and enabling the following line.
#     cat ${TMPFILE} | grep " *Storage Element [0-9]*:.*Full" | sed "s/ Storage Element //" | sed "s/Full :VolumeTag=//"
#
      cat ${TMPFILE} | grep "^Data Transfer Element [0-9]*:Full (Storage Element [0-9]" | awk '{printf "%s:%s\n",$7,$10}'
      rm -f ${TMPFILE} >/dev/null 2>&1
      exit $rtn
      ;;

   loaded)
      debug "Doing mtx -f $ctl $drive -- to find what is 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} >/dev/null 2>&1
      exit $rtn
      ;;

   slots)
      debug "Doing mtx -f $ctl -- to get count of slots"
      ${MTX} -f $ctl status | grep " *Storage Changer" | awk "{print \$5}"
      ;;
esac
