#!/bin/bash

# This script does backups of the files in /, /boot, and /opt, using
# rsync into time-specific directories, using hard links to the previous
# directory to reduce space.

#### Configuration: Edit the next few lines to set this script up.
# BUILDEXCLUDE: Full path the the build.exclude script that creates the
#   exclude list for rsync.
# CHECKMOUNT: Full path the the isbakmounted script that verifies the
#   backup drive is mounted
# MOUNTDIR: The backup drive to mount (IP:DIR).
# BACKUPDIR: Your mount point for the backup drive.
# OPTEXCLUDEDIR: Backup drive relative to your /opt. For instance, if you
#   mount your backup drive at /opt/backups, enter backups here.
# ROOTDIR: Subdirectory of BACKUPDIR where you store / (root) backups.
# BOOTDIR: Subdirectory of BACKUPDIR where you store /boot backups.
# OPTDIR: Subdirectory of BACKUPDIR where you store /opt backups.
BUILDEXCLUDE=/YOURSCRIPTDIR/build.exclude
CHECKMOUNT=/YOURSCRIPTDIR/is.bak.mounted
MOUNTDIR="YOURIPADDRESS:YOURNFSDIR"
BACKUPDIR=/opt/WHEREYOUMOUNTIT
OPTEXCLUDEDIR=WHEREYOUMOUNTIT
ROOTDIR=rootbackups
BOOTDIR=bootbackups
OPTDIR=optbackups
#### End of configuration

DATESTR=`date '+%Y-%m-%d-h%Hm%Ms%S'`

# Mount backup drive and verify it is mounted.
echo Mounting backup drive $BACKUPDIR
mount $MOUNTDIR $BACKUPDIR
if !(`$CHECKMOUNT`)
then
    echo "Backup drive is not mounted or dir is missing, aborting backup"
    umount $BACKUPDIR
    exit 1
fi

# Actually run the backups.

# Find the previous backup directory, if any, for hard links.
ROOTPREV=`ls -drt $BACKUPDIR/$ROOTDIR/root-* | tail -1`
BOOTPREV=`ls -drt $BACKUPDIR/$BOOTDIR/boot-* | tail -1`
OPTPREV=`ls -drt $BACKUPDIR/$OPTDIR/opt-* | tail -1`
if [ $ROOTPREV ]
then
  if (test -d $ROOTPREV)
  then
    echo Found previous root backup at $ROOTPREV
    ROOTPREV="--link-dest=$ROOTPREV"
  fi
fi

if [ $BOOTPREV ]
then
  if (test -d $BOOTPREV)
  then
    echo Found previous boot backup at $BOOTPREV
    BOOTPREV="--link-dest=$BOOTPREV"
  fi
fi

if [ $OPTPREV ]
then
  if (test -d $OPTPREV)
  then
    echo Found previous opt backup at $OPTPREV
    OPTPREV="--link-dest=$OPTPREV"
  fi
fi

# Make the exclude list for rsync.
$BUILDEXCLUDE /tmp/exclude_bu.list

# Create the target directories.
echo Making new backup directories $DATESTR
NEWROOTDIR=$BACKUPDIR/$ROOTDIR/root-$DATESTR
NEWBOOTDIR=$BACKUPDIR/$BOOTDIR/boot-$DATESTR
NEWOPTDIR=$BACKUPDIR/$OPTDIR/opt-$DATESTR
mkdir $NEWROOTDIR
mkdir $NEWBOOTDIR
mkdir $NEWOPTDIR

# Run the rsyncs.
echo `/bin/df | /bin/grep $BACKUPDIR`
echo Starting rsync for root
/usr/bin/rsync -a --delete $ROOTPREV --exclude-from=/tmp/exclude_bu.list / $NEWROOTDIR/
echo `/bin/df | /bin/grep $BACKUPDIR`
echo Starting rsync for boot
/usr/bin/rsync -a --delete $BOOTPREV /boot/ $NEWBOOTDIR/
echo `/bin/df | /bin/grep $BACKUPDIR`
echo Starting rsync for opt
/usr/bin/rsync -a --delete $OPTPREV --exclude=$OPTEXCLUDEDIR  /opt/ $NEWOPTDIR/
echo `/bin/df | /bin/grep $BACKUPDIR`

# Unmount backup dir, after waiting a short time to let the file system
# calm down.
echo Waiting 20 seconds...
sleep 20s
echo Unmounting file system $BACKUPDIR
umount $BACKUPDIR