dumpfs.sh

#!/bin/sh

die() {
   echo "$*" >&2
   exit 1
}

#
# Determine dump level based on what day it is:
#
#       0: Yearly (Jan 1)
#       1: Monthly (FMAMJJASOND 1)
#     2-8: Sunday -> Saturday
#       9: UNUSED (user checkpoint)
#
default_level() {
   # First get the desired incremental dump
   DUMP_LEVEL=$(expr `date +%w` + 2)

   # Monthly backups happen on the first of each month
   if test `date +%-d` = 1; then
      DUMP_LEVEL=1
      # Yearly backups occur on the first of January.
      if test `date +%-m` = 1; then
         DUMP_LEVEL=0
      fi
   fi

   echo $DUMP_LEVEL
}

#
# For each backup, create the file that will be the gzip'd dump of the
# filesystem, change the permissions to disallow reading, and then dump the
# filesystem into it with an inline gzip
#

dump_filesystem() {
   MOUNTPOINT=$1
   DEVICE=`mount | awk '{if($3 == "'${MOUNTPOINT}'") {gsub( /[^\/]*\//, "", $1 ); print $1} }'`
   DUMP="$path/dump_${DEVICE}.gz"
   echo "Backup of ${MOUNTPOINT} (${DEVICE})"
   touch $DUMP.tmp
   chmod 400 $DUMP.tmp
   /sbin/dump -${LEVEL}uLf - /dev/${DEVICE} | gzip -c > $DUMP.tmp
   mv $DUMP.tmp $DUMP
}

fl=`date '+%Y-%m-%d'`
host=`hostname -s`
path="/backup/dumpfs/${host}/${fl}"
PROG_NAME=`basename "$0"`

LEVEL=`default_level`
while getopts l: OPTION; do
   case ${OPTION} in
      l)
         LEVEL=${OPTARG}
         ;;
      \?)
         echo "Usage ${PROG_NAME} [-l dump_level]" >&2
         exit 2
         ;;
   esac
done

# If there is already a backup in this location, abort
if [ -f $path/COMPLETE ]; then
   DONE_LEVEL=`cat $path/LEVEL`
   die "A level $DONE_LEVEL backup is already present for today."
fi

echo "Performing a level ${LEVEL} dump"

# Make sure something is mounted to the backup directory
if { mount | grep -q /backup; }; then
  echo "Found /backup filesystem."
else
  mount /backup || \
     die "No filesystem mounted to /backup"
  echo "Mounted /backup"
fi

# Make the directory to store this backup
mkdir -p "$path"

# Indicate the level of the dump.
echo ${LEVEL} > $path/LEVEL

# Collect filesystems to be dumped
DUMPS=`grep -Ev '^\s*#' /etc/fstab | awk '{ if( $5 > 0 ) { print $5, $2 } }' | sort -n | awk '{print $2}'`
for fs in $DUMPS; do
   dump_filesystem $fs
done

# Indicate that we successfully completed the dumps
touch $path/COMPLETE