#!/bin/sh
#
# Wed Apr 30 11:02:23 CEST 2008, anleo
#

### Configuration {

# Mail recipient
RECIPIENT=andrea@cyberz.org

# How often a mail will be sent (in seconds) when tape change is needed
MAILNOTIFY=14400

# Log file
LOGFILE=/tmp/mtx.log

# Polling time when waiting for tape operations
TAPEDELAY=5

# Bacula console program
CONSOLE=/opt/csw/sbin/bconsole

# MT command
MT=/usr/bin/mt

# GNU Grep
GREP=/usr/sfw/bin/ggrep

# Changer status file
STATUS=/opt/csw/etc/bacula/mail-changer._TAPE_.status

# Space separated volumes list
VOLUMES=/opt/csw/etc/bacula/mail-changer._TAPE_.volumes

# Bsmtp
BSMTP=/opt/csw/sbin/bsmtp

# Email address
FROM="Bacula <bacula@nas.cyberz.org>"

### } End of configuration

# Variables from command line
TAPEDRIVE="$4"
COMMAND="$2"
SLOT="$3"
CVOLUME="$4"

DRIVEID=`basename $TAPEDRIVE`
STATUS=`echo $STATUS | sed s@_TAPE_@$DRIVEID@`;
VOLUMES=`echo $VOLUMES | sed s@_TAPE_@$DRIVEID@`;

if [ ! -f $STATUS ]; then
	echo 0 > $STATUS
fi

if [ ! -r $VOLUMES ]; then
	echo unable to read volume list, aborting

	exit 2
fi

VOLUMES=`cat $VOLUMES`;

NSLOT=`echo $VOLUMES | wc -w | awk '{ print $1 }'`

log() {
	echo `date`: $* >> $LOGFILE
}

volume() {
	if [ $1 -eq 0 -o $1 -gt $NSLOT ]; then
		echo '<new>'
	else
		echo $VOLUMES | awk '{ print $'$1' }';
	fi
}

readvolume() {
	log reading tape volume

	LABELTMPFILE=/tmp/`basename $0`.label.$$.tmp

	$MT -f $TAPEDRIVE rewind >/dev/null 2>&1

	dd if=$TAPEDRIVE of=$LABELTMPFILE bs=256k count=1 2>/dev/null

	VOL="`dd if=$LABELTMPFILE bs=1 skip=93 count=14 2>/dev/null`"

	rm -f $LABELTMPFILE

	log volume \"$VOL\" is loaded

	$MT -f $TAPEDRIVE rewind >/dev/null 2>&1

	echo $VOL
}

notify() {
	$BSMTP -h localhost -f "$FROM" -s "$1" $RECIPIENT
}

log command line '(pid '$$'):' $0 $*

log variables dump: tape $TAPEDRIVE, command $COMMAND, slot $SLOT, volume "$CVOLUME"

case "$COMMAND" in 
unload)
	log tape unload request

	if $MT -f $TAPEDRIVE status >/dev/null 2>&1; then
		if [ ! -f /tmp/noeject ]; then
			$MT -f $TAPEDRIVE offline
		fi

		echo 0 > $STATUS
	fi
	;;
	
load)
	if [ $SLOT -eq "0`cat $STATUS`" ]; then
		log slot already loaded

		exit 0
	fi

	log tape load request for slot $SLOT '('"`volume $SLOT`"')'

	STIME=`perl -e 'print time;'`

	# Number of mails sent so far
	NMAIL=0

	while :; do
		NOW=`perl -e 'print time;'`

		ELAPSED=`echo $NOW-$STIME-$NMAIL*$MAILNOTIFY | bc`

		log waiting for volume "`volume $SLOT`"...

		$MT -f $TAPEDRIVE status 2>&1 | grep -i offline >/dev/null

		if [ $? = 1 ]; then
			log tape has been loaded

			MVOLUME="`readvolume`";

			if [ "$MVOLUME" = "`volume $SLOT`" -o "`volume $SLOT`" = '<new>' ]; then
				log got expected volume "`volume $SLOT`", returning
		
				echo "Volume `volume $SLOT` (slot $SLOT) has been loaded" | notify "Bacula tape load confirmation";

				break;
			else
				log got unexpected volume "$MVOLUME", expecting "`volume $SLOT`"

				echo "Please load volume `volume $SLOT` (slot $SLOT). Current tape $MVOLUME has been offlined" | notify "Bacula tape change request (`volume $SLOT` required)";

				if [ ! -f /tmp/noeject ]; then
					$MT -f $TAPEDRIVE offline >/dev/null 2>&1
				fi

				NMAIL=`echo $NMAIL+1 | bc`
			fi
		else
			# tape is still offline (not tape loaded)

			if [ "$ELAPSED" -ge 0 ]; then
				log feel like sending email, elapsed is $ELAPSED

				echo "Please load volume `volume $SLOT` (slot $SLOT)" | notify "Bacula tape change request (`volume $SLOT` required)";

				NMAIL=`echo $NMAIL+1 | bc`
			fi
		fi

		sleep $TAPEDELAY
	done

	echo $SLOT > $STATUS

	;;

loaded)
	log is slot $SLOT loaded\?

	if [ "0`cat $STATUS`" -gt 0 ]; then
		log loaded slot is `cat $STATUS` 

		echo `cat $STATUS`;
	else
		log nothing loaded

		echo 0;
	fi
	;;

list)
	bash -c "echo {1..$NSLOT}"
	;;

volumes)
	for I in $VOLUMES; do
		echo $I
	done | awk '{ print NR":"$0 }'
	;;

slots)
	echo $VOLUMES | wc -w | awk '{ print $1 }'
	;;

*)
	log unknown command $COMMAND

	exit 1
esac

exit 0