#!/bin/bash
#
# Copyright 2012 Hewlett-Packard Development Company, L.P.
# All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
#
# This script generates iso image from the given kernel and ramdisk

SCRIPTNAME=`basename $0`
TMP_BUILD_DIR="/tmp/$SCRIPTNAME.$$"
QEMU_IMG="/usr/bin/qemu-img"
MKISOFS="/usr/bin/mkisofs"


function show_options() {

    echo "Usage: ${SCRIPTNAME} [options]"
    echo
    echo "Options:"

    echo "    -o output filename "
    echo "    -i initrd "
    echo "    -k kernel "
}

function cleanup() {

    v_print "Cleaning up.."
    rm -rf $TMP_BUILD_DIR
}

function err_print() {
    echo "ERROR: $@" 1>&2;
}

function v_print() {

    echo "$*"
}


# Parse command line options
ARGS=`getopt -o "o:i:k:" -l "output,initrd,kernel:" \
      -n "$SCRIPTNAME" -- "$@"`
if [ $? -ne 0 ];
then
        exit 1
fi

eval set -- "$ARGS"

while true ; do
    case "$1" in
        -o) OUTPUT_FILENAME=$2; shift 2 ;;
        -i) INITRD=$2; shift 2 ;;
        -k) KERNEL=$2; shift 2 ;;
        # *)  show_options ; exit 1 ;;
        --) shift; break ;;
    esac
done

# Verify whether kernel, initrd, and the image file is present
if [ -z "$OUTPUT_FILENAME" ]; then
    err_print "Output filename not provided."
    show_options
    exit 1
fi

if [ -z "$INITRD" ]; then
    err_print "Initrd not provided."
    show_options
    exit 1
fi

if [ -z "$KERNEL" ]; then
    err_print "Kernel not provided."
    show_options
    exit 1
fi

# Create a temporary build directory for holiding the contents of iso
TMP_IMAGE_DIR="$TMP_BUILD_DIR/image"
v_print "Creating temporary directory $TMP_IMAGE_DIR"
mkdir -p "$TMP_IMAGE_DIR"

# Copy isolinux bin to the isolinux directory
mkdir -p "$TMP_IMAGE_DIR/isolinux"
v_print "Copying isolinux.bin"
cp /usr/lib/syslinux/isolinux.bin "$TMP_IMAGE_DIR/isolinux"

# Copy initrd, kernel
v_print "Copying kernel to $TMP_IMAGE_DIR/vmlinuz"
cp $KERNEL "$TMP_IMAGE_DIR/vmlinuz"
if [ $? -ne 0 ]; then
    err_print "Failed to copy $KERNEL to $TMP_IMAGE_DIR"
    cleanup
    exit 1
fi

v_print "Copying initrd to $TMP_IMAGE_DIR/initrd"
cp $INITRD "$TMP_IMAGE_DIR/initrd"
if [ $? -ne 0 ]; then
    err_print "Failed to copy $INITRD to $TMP_IMAGE_DIR"
    cleanup
    exit 1
fi

# Generate isolinux.cfg for default booting
v_print "Generating isolinux.cfg"
echo "\
DEFAULT install
LABEL install
    menu label "Install image"
    kernel /vmlinuz
    append initrd=/initrd boot_method=vmedia --
TIMEOUT 5
PROMPT 0 " > "$TMP_IMAGE_DIR/isolinux/isolinux.cfg"

# Convert relative path output filename to absolute path
echo $OUTPUT_FILENAME | grep -q '^/'
if [ $? -ne 0 ]; then
    OUTPUT_FILENAME="$PWD/$OUTPUT_FILENAME"
fi

# Create the ISO
v_print "Generating the ISO"
cd $TMP_IMAGE_DIR && $MKISOFS -r -V "INSTALL_IMAGE" -cache-inodes -J -l -b isolinux/isolinux.bin  -no-emul-boot -boot-load-size 4 -boot-info-table -o $OUTPUT_FILENAME .

# Cleanup
cleanup