#!/bin/bash
#random random keyfile generator

ARGS=6
E_BADARGS=85		


if [ $# -ne "$ARGS" ]
then
	echo
	echo "Usage: `basename $0` [keyfile_name] [extension] [amount] {bytes} {min-count} {max-count}"
#	echo "Notice: [sudo apt-get install randomsound] before use"
	echo "uses dd with /dev/urandom"
	echo	
	echo "Example: `basename $0` picture jpg 10 1024 512 4096"
	echo "--will make directory named picture_10"
	echo "--with 10 keyfiles named picture1.jpg to picture10.jpg"
	echo "--keyfile size will be random between .52MB & 4.19MB"
	echo	
	exit $E_BADARGS
fi

filename=$1
extension=$2
amount=$3
bytes=$4
count_min=$5
count_max=$6


echo
#echo "Restarting entropy with randomsound (doesn't always have the best entropy from startup)"
#sudo /etc/init.d/randomsound restart

mkdir "$filename"_"$amount"

maxsize=`echo "$bytes*$count_max*.000001" | bc`
minsize=`echo "$bytes*$count_min*.000001" | bc`
echo
echo "MIN: $minsize""MB"" MAX: $maxsize""MB"

for a in `seq $amount`
do
	echo
	entropy1=`cat /proc/sys/kernel/random/entropy_avail`
	echo -n "Making $filename$a.$extension with entropy of:$entropy1"

	number=0
	FLOOR=$count_min	
	RANGE=$count_max
	
	#initialize random number range
	while [ "$number" -le $FLOOR ]
		do
			SEED=$(head -1 /dev/urandom | od -N 1 | awk '{ print $2 }')
			RANDOM=$SEED
			number=$RANDOM	
			let "number %= $RANGE" # Scales $number down within $RANGE.
		done

	currentfilesize=`echo "$bytes*$number*.000001" | bc`    #helpful for large ones
	
	echo " will be $currentfilesize""MB"
	echo "dd if=/dev/urandom of=./"$filename"_"$amount"/"$filename""$a"."$extension" bs=$bytes count=$number"
	
	dd if=/dev/urandom of=./"$filename"_"$amount"/"$filename""$a"."$extension" bs=$bytes count=$number
	
	entropy2=`cat /proc/sys/kernel/random/entropy_avail`
	totale=`echo "$entropy1-$entropy2" | bc`
	
#	echo ".:: Pausing to generate more entropy ($totale used $entropy2 left) ::."
#	sleep 3	
	
	echo
done

echo "Made $a keyfile(s) in /""$filename""_""$amount"
echo

exit 0