#!/bin/bash
# Syntax:   filldisk [quiet|verbose]<Enter>
#
# This applet fills the disk with files containing a repeating string.
# It has two purposes: overwrite any existing deleted files, making undelete
# difficult (a _good_ idea for the security-anal), and actually writing to 
# the majority of the empty blocks on the disk, giving the drives a chance to 
# exercise their block checking ability.  It does not completely fill the 
# drive; it leaves 1-2M at the end of the regular data space, never touches
# the space reserved for root, and doesn't write to space already containing
# files.
# It currently only fills the partition which contains FILLDIR.
#
# The idea came from Richard Johnson (root@chaos.analogic.com); thanks Richard!
#
# This applet is copyright 1998 by William Stearns (wstearns@pobox.com).  It 
# is released under the GNU Public License.  Contact the author if you do not 
# have a copy of this license.

#The following is the name of a directory that will hold the temporary fill 
#files.  It must _NOT_ exist.  It must be an absolute directory (i.e. starting
#with "/".  If either of the above conditions are not met, this applet will 
#not run.
FILLDIR="/root/slackspacefilldir"	
#The following should be a 63 byte string.
FILLSTRING="SECURITY        SECURITY        SECURITY        SECURITY       "
# for ref, "0        1         2         3         4         5         6   "
# 63 bytes="123456789012345678901234567890123456789012345678901234567890123"


case `echo ${1} | tr A-Z a-z` in
help|--help)
	echo Syntax: ${0} [quiet\|verbose\|help]
	echo This program fills the available space on the disk containing
	echo your home directory, then frees the space up again.
	echo \"quiet\" mode only outputs errors.  \"--\" can be used in front
	echo of any of the options.
	echo Copyright 1998 William Stearns, released under the GNU public
	echo license.  Contact the author at wstearns@pobox.com if you 
	echo do not have a copy of this.
	echo
	exit
	;;
quiet|--quiet)		VERBOSE=NO					;;
verbose|--verbose)	VERBOSE=YES					;;
*)			VERBOSE=YES					;;
esac

cd ~

if [ -e ${FILLDIR} ]; then
	echo \"${FILLDIR}\" already exists.  This program will not continue
	echo as this directory of file may hold something you wish to keep.
	echo if you wish to continue, please remove it by hand and rerun 
	echo ${0} ${1} .
	exit
fi
if [ "`echo ${1} | cut -b 1`" != "/" ]; then
	echo \"${FILLDIR}\" does not start with a \"/\".  ${0} needs an 
	echo absolute path for its temporary directory.  Please edit
	echo ${0} and enter a different directory name in the FILLDIR line,
	echo and rerun ${0} ${1} .
	exit
fi

if [ ${VERBOSE} = "YES" ]; then
	echo Creating fill directory.
fi
mkdir ${FILLDIR}

cd ${FILLDIR}
if [ ${VERBOSE} = "YES" ]; then
	echo creating base 1 megabyte file
fi
COUNT=0
rm -f 1MEG
touch 1MEG
while [ ${COUNT} -lt 1024 ]; do
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	echo "${FILLSTRING}" >>1MEG
	COUNT=$[${COUNT}+1]
done

if [ ${VERBOSE} = "YES" ]; then
	echo filling drive
fi
COUNT=2
while [ `df ~/${FILLDIR} | grep -v '^Filesystem' | awk '{print $4}'` -gt 2048 ]; do
	cp 1MEG 1MEG.${COUNT}
	COUNT=$[${COUNT}+1]
done
if [ ${VERBOSE} = "YES" ]; then
	echo $[${COUNT}-1] 1-megabyte files were written.
	df
fi

if [ ${VERBOSE} = "YES" ]; then
	echo removing files
fi
cd ..
rm -f ${FILLDIR}/*
rmdir ${FILLDIR} 
if [ ${VERBOSE} = "YES" ]; then
	echo done
	df
fi