#!/bin/bash
# (c) Steve Parker, http://steve-parker.org/
# 19th March 2010
# Licensed under the GPL Version 2

# wrapper for dd to act like Solaris' mkfile utility.
# mkfile adds "-n" (create empty file) and "-v" (verbose) which I can't
# be bothered to implement. However, I have added "-b" to specify a blocksize,
# and "-q" to be quiet

function usage()
{
  echo "Usage: mkfile [ -i infile ] [ -q ] [-b blocksize ] size[k|m|g] filename"
  echo "Blocksize is 512 bytes by default."
  exit 2
}

function humanreadable ()
{
multiplier=1
case $1 in
  *b)	multiplier=1		;;
  *k)	multiplier=1024		;;
  *m)	multiplier=1048576 	;;
  *g) 	multiplier=1073741824	;;
esac
numeric=`echo $1 | tr -d 'k'|tr -d 'm'|tr -d 'g'|tr -d 'b'`
expr $numeric \* $multiplier
}

# mkfile uses 512 byte blocks by default - so shall we.
bs=512
quiet=0
INFILE=/dev/zero

while getopts 'i:b:q?' argv
do
  case $argv in
	b) bs=$OPTARG		;;
	b) INFILE=$OPTARG	;;
	q) quiet=1		;;
	\?) usage		;;
	*) usage		;;
  esac
done

for i in `seq 2 ${OPTIND}`
do
  shift
done

if [ -z "$1" ]; then
  echo "ERROR: No size specificed"
fi
if [ -z "$2" ]; then
  echo "ERROR: No filename specificed"
fi
if [ "$#" -ne "2" ]; then
  usage
fi

SIZE=`humanreadable $1`
FILENAME="$2"

BS=`humanreadable $bs`

COUNT=`expr $SIZE / $BS`
CHECK=`expr $COUNT \* $BS`
if [ "$CHECK" -ne "$SIZE" ]; then 
  echo "Warning: Due to the blocksize requested, the file created will be `expr $COUNT \* $BS` bytes and not $SIZE bytes"
fi

echo -en "Creating $SIZE byte file $FILENAME...."

dd if=$INFILE bs=$BS count=$COUNT of="$FILENAME" 2>/dev/null
ddresult=$?
if [ "$quiet" -ne "1" ]; then
  # We all know that you're goint to do this next - let's do it for you:
  if [ "$ddresult" -eq "0" ]; then
    echo "Finished:"
  else
    echo "An error occurred. dd returned code $ddresult."
  fi
  ls -l "$FILENAME" && ls -lh "$FILENAME"
fi

exit  $ddresult