#
# backupninja handler to do incremental backups using
# rsync and hardlinks, based on
#
#   http://www.mikerubel.org/computers/rsync_snapshots/
#
# feedback: rhatto at riseup.net | gpl
#
# config file options
# -------------------
#
#   [general]
#   log = rsync log file
#   partition = partition where the backup lives
#   fsck = set to 1 if fsck should run on $partition after the backup is made
#   read_only = set to 1 if $partition is mounted read-only
#   mountpoint = backup partition mountpoint or backup main folder
#   backupdir = folder relative do $mountpoint where the backup should be stored
#   days = number of backup increments (min = 5)
#   lockfile = lockfile to be kept during backup execution
#
#   [source]
#   include = include folder on backup
#   exclude = exclude folder on backup
#   from = local or remote
#   ssh = ssh command line (remote only)
#   rsync = rsync command line
#
#   [services]
#   initscripts = absolute path where scripts are located
#   service = script name to be stoped at the begining of the backup and started at its end
#

setsection general
getconf log /var/log/backupninja-rub.log
getconf partition
getconf fsck
getconf read_only
getconf mountpoint
getconf backupdir
getconf rotate
getconf days
getconf lockfile

setsection source
getconf from local
getconf rsync "rsync -av --delete"
getconf ssh ssh
getconf user
getconf host
getconf include
getconf exclude

setsection services
getconf initscripts
getconf service

backupdir="$mountpoint/$backupdir"

if [ ! -d "$backupdir" ]; then 
  error "Backupdir $backupdir does not exist"
  exit 1
fi

if [ -z "$days" ]; then
  keep="4"
else
  keep="`echo $days - 1 | bc -l`"
fi

if [ ! -z "$lockfile" ]; then
  touch $lockfile || warning "Could not create lockfile $lockfile"
fi

for path in $exclude; do
  EXCLUDES="$EXCLUDES --exclude=$path"
done

if [ ! -z "$service" ]; then
  for daemon in $service; do
    info "Stopping service $daemon..."
    $initscripts/$daemon stop
  done
fi

function rotate {

  # please use an absolute path

  if [[ "$2" < 4 ]]; then
    error "Rotate: minimum of 4 rotations"
    exit 1
  fi

  if [ -d $1.$2 ]; then
    mv $1.$2 $1.tmp
  fi

  for ((n=`echo "$2 - 1" | bc`; n >= 0; n--)); do
    if [ -d $1.$n ]; then
      dest=`echo "$n + 1" | bc`
      mv $1.$n $1.$dest
      touch $1.$dest
    fi
  done

  if [ -d $1.tmp ]; then
    mv $1.tmp $1.0
  fi

  if [ -d $1.1 ]; then
    cp -alf $1.1/. $1.0
  fi

}

echo "Starting backup at `date`" >> $log

if [ "$read_only" == "1" ] || [ "$read_only" == "yes" ]; then
  if [ -d "$mountpoint" ]; then
    mount -o remount,rw $mountpoint
    if (($?)); then
      error "Could not mount $mountpoint"
      exit 1
    fi
  fi
fi

for SECTION in $include; do

  section="`basename $SECTION`"

  if [ ! -d "$backupdir/$SECTION/$section.0" ]; then
    mkdir -p $backupdir/$SECTION/$section.0
  fi
 
  info "Rotating $backupdir/$SECTION/$section..."
  echo "Rotating $backupdir/$SECTION/$section..." >> $log
  rotate $backupdir/$SECTION/$section $keep
  info "Syncing $SECTION on $backupdir/$SECTION/$section.0..."

  if [ "$from" == "local" ]; then
    $rsync $EXCLUDES /$SECTION/ $backupdir/$SECTION/$section.0/ >> $log
    if [ "$?" != "0" ];
      error "Rsync error when trying to transfer $SECTION"
    fi
  elif [ "$from" == "remote" ]; then
    if [ -z "$user" ] || [ -z "$host" ]; then
      error "Config file error: either user or host was not specified"
      exit 1
    else
      $rsync $EXCLUDES -e "$ssh" $user@$host:/$SECTION/ $backupdir/$SECTION/$section.0 >> $log
      if [ "$?" != "0' ];
        error "Rsync error when trying to transfer $SECTION"
      fi
    fi
  else
    error "Invalid source $from"
    exit 1
  fi

  touch $backupdir/$SECTION/$section.0

done

if [ "$read_only" == "1" ] || [ "$read_only" == "yes" ]; then
  mount -o remount,ro $mountpoint
fi

if [ "$fsck" == "1" ] || [ "$fsck" == "yes" ]; then
  umount $mountpoint
  if (($?)); then
    warning "Could not umount $mountpoint to run fsck"
  else
    fsck -v -y $partition >> $log
    mount $mountpoint
  fi
fi

if [ ! -z "$service" ]; then
  for daemon in $service; do
    info "Starting service $daemon..."
    $initscripts/$daemon start
  done
fi

if [ ! -z "$lockfile" ]; then
  rm $lockfile || warning "Could not remove lockfile $lockfile"
fi

echo "Finnishing backup at `date`" >> $log