build_image

#!/bin/bash
IMAGE_SIZE=$((4*1024*1024)) #4 megabytes
KERNEL="poseidon.sys"
IMAGE="PoseidonOS.img"
MBOOT=/usr/share/syslinux/mboot.c32

function fail() {
	echo "$1";
	exit 1;
}

function prereq() {
	local c x
	if [ "$1" = "f" ]; then c=stat;x=file; else c=which;x=program; fi
	if [ -z "$3" ]; then
		$c "$2" &>/dev/null || fail "$x $2 not found"
	else
		$c "$2" &>/dev/null || fail "$x $2 (from package $3) not found"
	fi
}

prereq x mkfs.vfat dosfstools
prereq x mcopy mtools
prereq x syslinux
prereq f "$MBOOT" syslinx

rm -f "$IMAGE"

echo "create image"
dd if=/dev/zero of="$IMAGE" bs=4k count=$((IMAGE_SIZE/4096)) 2> /dev/null

echo "format image"
mkfs.vfat "$IMAGE" || fail "could not format $IMAGE"

echo "copy kernel"
mcopy -i "$IMAGE" ../kernel/"$KERNEL" ::/

echo "copy mboot"
mcopy -i "$IMAGE" "$MBOOT"  ::/

#create syslinux.cfg
echo "DEFAULT PoseidonOS
LABEL PoseidonOS
	SAY Now booting $KERNEL
	KERNEL mboot.c32
	APPEND $KERNEL" | mcopy -i "$IMAGE" - ::syslinux.cfg

echo "install syslinux"
syslinux -i "$IMAGE" || fail "unable to install syslinux to $IMAGE"