#!/bin/bash

# Create a bootable harddisk (or compact flash) image from
# a partition definition given from command line
#
# (C) 2006 Pengutronix
#


Usage() {
cat <<-EOF

Usage: `basename "$0"` OPTIONS <svn rep>

    -h              this help
    -m <stage1>     path to grub stage1
    -n <stafe2>     path to grub stage2
    -o <hdimg file> resulting hd image
    -i <img file>   filesystem image
    -p <def>       partition definition (can be given multiple times)
    
    A partition definition has the form
    start_sector:end_sector:partition_type:[imagefile]
EOF
}

# usage: pad from to blocks
#        cat $from to $to and pad the output to $blocks * 512 bytes
pad() {
	from="$1"
	to="$2"
	blocks="$3"

	if [ ! -f "$from" ]; then
		echo "$from does not exist"
		exit 1
	fi

	fromsize=$(stat --printf "%s" "$from")

	if [ $(($fromsize)) -gt $(($blocks * 512)) ]; then
		echo "warning: $from truncated. Need $fromsize bytes, but have only $(($blocks * 512))!"
	fi

	cat $from /dev/zero | dd bs=512 count=$(($blocks)) >> "$to" 2>/dev/null
}


partcount=0

while getopts "hm:n:o:p:" OPT
do
    case "$OPT" in
        h)  Usage
	    exit 1
            ;;
	m)  STAGE1="$OPTARG"
	    ;;
	n)  STAGE2="$OPTARG"
	    ;;
	o)  IMAGEFILE="$OPTARG"
	    ;;
	p)  partcount=$(($partcount + 1))
	    PART[$partcount]="$OPTARG"
	    ;;
    esac
done

if [ "$partcount" == 0 ]; then
	echo "need at least one partition definition"
	exit 1
fi

if [ "$partcount" -gt 4 ]; then
	echo "a maximum of four partitions is allowed"
	exit 1
fi

if [ -z "$IMAGEFILE" ]; then
	echo "no output image file given"
	exit 1
fi

IMAGETMP=$(mktemp)

# get the first 446 bytes of grub stage1 or from /dev/zero
if [ -n "$STAGE1" ]; then
	echo "using stage1 file $STAGE1"
	if [ ! -r "$STAGE1" ]; then
		echo "cannot open stage1 file $STAGE1"
		exit 1
	fi

	dd if="$STAGE1" bs=446 count=1 > $IMAGEFILE 2>/dev/null
else
	dd if=/dev/zero bs=446 count=1 > $IMAGEFILE 2>/dev/null
fi

# add offset to first partition and fill it with grub stage2 if given
offset=$(( $(echo ${PART[1]} | awk -F: '{print $1}') - 1))
if [ -n "$STAGE2" ]; then
	echo "using stage2 file $STAGE2"
	if [ ! -r "$STAGE2" ]; then
		echo "cannot open stage2 file $STAGE2"
		exit 1
	fi
	pad "$STAGE2" "$IMAGETMP" $(($offset))
else
	cat /dev/zero | dd bs=512 count=$offset > "$IMAGETMP" 2>/dev/null
fi

# append the partitions

# mark the first partition bootable
extraarg="-c"

for i in $(seq 4); do
	pstart=$(( $(echo ${PART[$i]} | awk -F: '{print $1}') ))
	pend=$(( $(echo ${PART[$i]} | awk -F: '{print $2}') ))
	ptype=$(( $(echo ${PART[$i]} | awk -F: '{print $3}') ))
	pimage=$(echo ${PART[$i]} | awk -F: '{print $4}')
	psize=$(($pend - $pstart + 1))
		
	if [ $i -gt $partcount ]; then
		psize=0
	fi

	echo "Generating partition $i (start=$pstart, size=$psize type=$ptype)"

	# add 0x55aa magic to last partition in table
	if [ $i == 4 ]; then
		extraarg="-m"
	fi

	genpart $extraarg -b $pstart -s $psize -t $ptype >> $IMAGEFILE

	if [ -n "$pimage" ]; then
		echo "Initializing partition $i with $pimage"
		pad "$pimage" "$IMAGETMP" $(($psize))
	fi

	extraarg=""
done

cat $IMAGETMP >> $IMAGEFILE
rm -f $IMAGETMP