#!/bin/bash

###
 # Copyright (C) 2001  Eugenio Diaz <getnito@yahoo.com>
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions
 # are met:
 #
 # 1. Redistributions of source code must retain the above copyright
 #    notice, this list of conditions and the following disclaimer.
 # 2. Redistributions in binary form must reproduce the above
 #    copyright notice, this list of conditions and the following
 #    disclaimer in the documentation and/or other materials provided
 #    with the distribution.
 # 3. Neither the name of the University nor the names of its
 #    contributors may be used to endorse or promote products derived
 #    from this software without specific prior written permission.
 #
 # THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS''
 # AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 # TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 # PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS
 # OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 # USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 # ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 # OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 # SUCH DAMAGE.
 #
 ##
 #
 # This script will redirect the backup directory to implement desired
 # backup schedules.
 #
 # We will use just a seven day format where we just move a link that
 # represents the backup directory, to point to the day of the week.
 ##


#
# Configuration Parameters
#

if [ "$1" = "monthly" ]; then
   REALDIR="monthly"
else
   REALDIR=`date +%A`
fi

BACKUPPART=${BACKUPPART:-"/backup"}
BACKUPDIR=${BACKUPDIR:-"current"}

echo "### Start of Backup Rotation ###"
echo "Using backup partition: $BACKUPPART"

echo -n "Remounting backup partition read-write ... "
if ( mount $BACKUPPART -o remount,rw &> /dev/null ) then
   echo "done."
else
   echo "failure!"
   echo "There were problems remounting $BACKUPPART in read-write mode!"
   echo "Rotation not made!"
   echo "### End of Backup Rotation ###"
   exit 1
fi

echo -n "Checking that no directory named \"$BACKUPDIR\" exists ... "
if [ -d $BACKUPPART/$BACKUPDIR -a ! -L $BACKUPPART/$BACKUPDIR ]; then
   echo "failure!"
   echo "Directory \"$BACKUPDIR\" exists. Can't create link!"
   echo "Rotation not made!"

   echo -n "Remounting backup partition read-only ... "
   if ( mount $BACKUPPART -o remount,ro &> /dev/null ) then
      echo "done."
   else
      echo "failure!"
      echo "There were problems remounting $BACKUPPART in read-only mode!"
      echo "### End of Backup Rotation ###"
      exit 1
   fi
   echo "### End of Backup Rotation ###"
   exit 1
else
   echo "done."
fi

cd $BACKUPPART

echo -n "Creating link: $BACKUPDIR --> $REALDIR ... "
if ( ln -snf $REALDIR $BACKUPDIR &> /dev/null ) then
   echo "done."
else
   echo "failure!"
   echo "There were problems creating link!"
   echo "Rotation not made!"

   echo -n "Remounting backup partition read-only ... "
   if ( mount $BACKUPPART -o remount,ro &> /dev/null ) then
      echo "done."
   else
      echo "failure!"
      echo "There were problems remounting $BACKUPPART in read-only mode!"
      echo "### End of Backup Rotation ###"
      exit 1
   fi
   echo "### End of Backup Rotation ###"
   exit 1
fi

echo -n "Remounting backup partition read-only ... "
if ( mount $BACKUPPART -o remount,ro &> /dev/null ) then
   echo "done."
else
   echo "failure!"
   echo "There were problems remounting $BACKUPPART in read-only mode!"
   echo "### End of Backup Rotation ###"
   exit 1
fi
echo "### End of Backup Rotation ###"

## end of script