#! /bin/sh
# (c) Copyright 2012 Fabio Erculiani <lxnay@sabayon.org>
# Licensed under terms of GPLv2

export LC_ALL=C

# Expected env variables:
# PATHS_TO_REMOVE = ";" separated list of paths to rm -rf
# PATHS_TO_EMPTY = ";" separated list of paths to rm -rf (keeping the dir)
# RELEASE_STRING
# RELEASE_VERSION
# RELEASE_DESC
# RELEASE_FILE

if [ ${#} -ne 4 ]; then
	echo "usage: ${0} <path to regular file containing the image> <size in Mb> <source boot files dir> <source chroot>"
	exit 1
fi

FILE="${1}"
SIZE="${2}"
BOOT_DIR="${3}"
CHROOT_DIR="${4}"

cleanup_loopbacks() {
	sync
	sync
	sleep 5
	sync
	[[ -n "${tmp_dir}" ]] && { umount "${tmp_dir}" &> /dev/null; rmdir "${tmp_dir}" &> /dev/null; }
	sleep 1
	[[ -n "${vfat_part}" ]] && losetup -d "${vfat_part}" 2> /dev/null
	[[ -n "${ext_part}" ]] && losetup -d "${ext_part}" 2> /dev/null
	[[ -n "${DRIVE}" ]] && losetup -d "${DRIVE}" 2> /dev/null
}
trap "cleanup_loopbacks" 1 2 3 6 9 14 15 EXIT

# Erase the file
echo "Generating the empty image file at ${FILE}"
dd if=/dev/zero of="${FILE}" bs=1024000 count="${SIZE}"
[[ "$?" != "0" ]] && exit 1

DRIVE=$(losetup -f "${FILE}" --show 2> /dev/null)
if [ -z "${DRIVE}" ]; then
	echo "Cannot execute losetup for $FILE"
	exit 1
fi

echo "Configured the loopback partition at ${DRIVE}"

# Calculate size using fdisk
SIZE=$(fdisk -l "${DRIVE}" | grep Disk | grep bytes | awk '{print $5}')
CYLINDERS=$((SIZE/255/63/512))
# Magic first partition size, given 9 cylinders below
MAGICSIZE="73995264"
STARTOFFSET="32256"

echo "Disk size    : ${SIZE} bytes"
echo "Disk cyls    : ${CYLINDERS}"
echo "Magic size   : ${MAGICSIZE} bytes (boot part size)"
echo "Start offset : ${STARTOFFSET} bytes"

# this will create a first partition that is 73995264 bytes long
# Starts at sect 63, ends at sect 144584, each sector is 512bytes
# In fact it creates 9 cyls
{
echo ,9,0x0C,*
echo ,,,-
} | sfdisk -D -H 255 -S 63 -C $CYLINDERS $DRIVE

sleep 2

# The second partiton will start at block 144585, get the end block
ENDBLOCK=$(fdisk -l "${DRIVE}" | grep "${DRIVE}p2" | awk '{print $3}')
EXTSIZE=$(((ENDBLOCK - 144585) * 512))
# Get other two loopback devices first
EXTOFFSET=$((STARTOFFSET + MAGICSIZE))

echo "ExtFS size   : ${EXTSIZE} bytes"
echo "ExtFS offset : ${EXTOFFSET} bytes"

# Get other two loopback devices first
vfat_part=$(losetup -f --offset "${STARTOFFSET}" --sizelimit "${MAGICSIZE}" "${FILE}" --show 2> /dev/null)
if [ -z "${vfat_part}" ]; then
	echo "Cannot setup the vfat partition loopback"
	exit 1
fi


ext_part=$(losetup -f --offset "${EXTOFFSET}" --sizelimit "${EXTSIZE}" "${FILE}" --show 2> /dev/null)
if [ -z "${ext_part}" ]; then
	echo "Cannot setup the ext3 partition loopback"
	exit 1
fi

echo "VFAT Partiton at   : ${vfat_part}"
echo "ExtFS Partition at : ${ext_part}"

# Format vfat
echo "Formatting VFAT ${vfat_part}..."
mkfs.vfat -n "boot" -F 32 "${vfat_part}" || exit 1

# Format extfs
echo "Formatting ExtFS ${ext_part}..."
mkfs.ext3 -L "Sabayon" "${ext_part}" || exit 1

tmp_dir=$(mktemp -d)
if [[ -z "${tmp_dir}" ]]; then
	echo "Cannot create temporary dir"
	exit 1
fi
chmod 755 "${tmp_dir}" || exit 1

sleep 2
sync

echo "Setting up the boot directory content, mounting on ${tmp_dir}"
mount "${vfat_part}" "${tmp_dir}"
cp -R "${BOOT_DIR}"/* "${tmp_dir}"/ || exit 1
umount "${tmp_dir}" || exit 1

echo "Setting up the extfs directory content, mounting on ${tmp_dir}"
mount "${ext_part}" "${tmp_dir}"
rsync -a -H -A -X --delete-during "${CHROOT_DIR}"/ "${tmp_dir}"/ || exit 1

# work out paths to empty and paths to remove
oldifs="${IFS}"
IFS=";"
if [ -n "${PATHS_TO_REMOVE}" ]; then
	for path in "${tmp_dir}"/${PATHS_TO_REMOVE}; do
		if [ -e "${path}" ]; then
			echo "Removing: ${path}"
			rm -rf "${path}"
		fi
	done
fi
if [ -n "${PATHS_TO_EMPTY}" ]; then
	for path in "${tmp_dir}"/${PATHS_TO_EMPTY}; do
		if [ -d "${path}" ]; then
			echo "Emptying: ${path}"
			rm -rf "${path}"/*
		fi
	done
fi
IFS="${oldifs}"

if [ -n "${RELEASE_FILE}" ]; then
	release_file="${tmp_dir}"/"${RELEASE_FILE}"
	release_dir=$(dirname "${release_file}")
	[[ ! -d "${release_dir}" ]] && { mkdir -p "${release_dir}" || exit 1; }
	echo "${RELEASE_STRING} ${RELEASE_VERSION} ${RELEASE_DESC}" > "${release_file}"
fi

umount "${tmp_dir}" || exit 1

cleanup_loopbacks
echo "Your MMC image \"${FILE}\" is ready"