#!/bin/bash 
# ---------------------------------------
# Variablen

IDENT="srv02"
DATUM=`date "+%Y-%m-%d_%H"`
IDSTRING=${IDENT}-${DATUM}
TAPE="/dev/nst0"
TEMP="/tmp"
LOGDIR="/var/log/backup"
LOGFILE="$LOGDIR/${IDSTRING}.log"
TAPESTATUS="$LOGDIR/tapestatus-$DATUM.log"
BACKOUT="$TEMP/backout"
BACKERR="$TEMP/backerr"

hasError=""

COMMAND="/bin/tar"
OPTIONS="--create --verbose --one-file-system \
	 --gzip --file=$TAPE --totals \
         --blocking-factor=128"
#         --ignore-failed-read --blocking-factor=128"

# FILESYSTEME="/etc /doesnot-exist /root"
FILESYSTEME="/etc /root"

MUTT="/usr/bin/mutt"
LOGGER="/usr/bin/logger"
ADMINMAIL=backup-admin@myprovider.dot

# ---------------------------------------
# Funktionen

initialize () {
   if [ ! -d $LOGDIR ]; then
      mkdir -p $LOGDIR
   fi
   : > $TAPESTATUS
   : > $LOGFILE
   : > $BACKOUT
   : > $BACKERR

}

logme () {
   DATUM=`date "+%Y-%m-%d %H:%M"`
   echo -e "$DATUM  $1" >> $LOGFILE 
   
}

preBackup () {
   logme "+ preBackup: start"

   # -- hier können Tasks vor der Sicherung ausgeführt werden,
   # -- etwa der Dump einer Datenbank oder einen Dienst anhalten
   
   logme "- preBackup: finished"
}

postBackup() {
   logme "+ postBackup: start"

   # -- Aufräumarbeiten nach einer Sicherung
   # -- z.B. Dienste  wieder starten

   logme "- postBackup: finished"
}


# === MAIN ==============================

initialize

# ---------------------------------------
#  vor dem Backup

preBackup

logme "+ check tape status"

mt -f $TAPE status 1>> $TAPESTATUS 2>&1 || hasError="FirstStatus "
mt -f $TAPE rewind 1>> $TAPESTATUS 2>&1 || hasError="${hasError}Rewind "

if grep WR_PROT $TAPESTATUS > /dev/null
then
   hasError="${hasError}WriteProtect "
fi

if [ "$hasError" == "" ]; then
   logme "- check tape status: ok"
else
   logme "- check tape status: errors on: $hasError"
fi

# ---------------------------------------
#  Sicherung

# debug
echo "|$hasError|"

if [ "$hasError" == "" ]; then

   logme "+ starting backups"

   for filesys in $FILESYSTEME; do

      logme "+-> next backup: $filesys"

      $COMMAND $OPTIONS -C $filesys . \
         1>> $BACKOUT 2>> $BACKERR || hasError="${hasError} [$filesys]"

   done

   if [ "$hasError" == "" ]; then
      logme "- backups done"
   else
      logme "- backups done: errors on: $hasError"
      hasError="$hasError FILESYS "
   fi

else
   logme "!!! tape error, no backup done"
fi

# -- debug
echo "|$hasError|"

# ---------------------------------------
#  Nach dem Backup

lastError=""

logme "+ unload tape"
mt -f $TAPE status 1>> $TAPESTATUS 2>&1 || lastError="LastStatus "
mt -f $TAPE rewoff 1>> $TAPESTATUS 2>&1 || lastError="${lastError}Unload "

if [ "$lastError" == "" ]; then
   logme "- unload tape: done"
else
   logme "- unload tape: errors: $lastError"
   hasError="${hasError} $lastError"
fi

# -- debug
echo "|$hasError|"

postBackup

# ---------------------------------------
# Logfile komprimieren

zcat $BACKOUT >> $LOGFILE
gzip -9 $LOGFILE

# ---------------------------------------
# Infomail senden

if [ "$hasError" == "" ]; then
   $MUTT -x -s "$IDSTRING backup done, OK" $ADMINMAIL < $LOGFILE
else
   ATTACH=""
   case "$hasError" in
   *FirstStatus*)
      SUBJECT="$IDSTRING backup ERROR: no tape available"
      ;;
   *Rewind*)
      SUBJECT="$IDSTRING backup ERROR: could not rewind tape"
      ;;
   *WriteProtect*)
      SUBJECT="$IDSTRING backup ERROR: tape is write protected"
      ;;
   *FILESYS*)
      SUBJECT="$IDSTRING backup ERROR: error with filesystems"
      gzip -f -9 $BACKOUT
      ATTACH="-a $BACKOUT.gz"
      ;;
   *LastStatus*)
      SUBJECT="$IDSTRING backup done, ERROR: last status problem, suspect"
      ;;
   *Unload*)
      SUBJECT="$IDSTRING backup done, ERROR: could not unload tape"
      ;;
   *)
      SUBJECT="$IDSTRING backup ERROR: unknown error"
      ;;
   esac

   $MUTT -x -a $TAPESTATUS -a $BACKERR $ATTACH -s "$SUBJECT" $ADMINMAIL < $LOGFILE
   # -- syslog Eintrag erzeugen

   $LOGGER "$SUBJECT"

fi