#!/bin/ksh


# Define the MKBOOT_ISOLINUX and/or MKBOOT_MENUC32 environment variables to override their default
# locations. 

ISOLINUX=${MKBOOT_ISOLINUX:-/usr/share/syslinux/isolinux.bin}
MENUC32=${MKBOOT_MENUC32:-/usr/share/syslinux/menu.c32}

#### END of configuration section.

export TARGET="/tmp/makebootcd.$$"

function cleanup
{ 
  rm -rf $TARGET
  exit 1
}

function execute
{
  $*
  if [[ $? -ne 0 ]]
  then
    echo "Command '$*' ended in an error" 1>&2
	cleanup
  fi 
}

trap "cleanup" 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 

function printHelp 
{
  (
    echo $*
	echo ""
    echo "Usage: makebootiso <xmlspec> <outputIso>" 
	echo ""
	echo "  Takes an xml specification of one or more systems to boot"
	echo "  and creates an output ISO image that can be put onto a USB or CD/DVD"
	echo "  for booting a system using isolinux."
	echo ""
	echo "  Example: "
	echo "    # create the iso"
	echo "    makebootiso example/boot.xml boot.iso"
	echo "    # copy to USB "
	echo "    dd if=boot.iso of=/dev/sda bs=10M "
	echo ""
	echo "  The XML file consists of two parts:"
	echo "  Part 1 describes a number of kernel/initrd pairs identified "
	echo "  by symbolic short names for use by isolinux."
	echo "  Part 2 describes the systems to boot. For each system to boot"
	echo "  a short label and longer one line description are specified,"
	echo "  together with a reference to kernel/initrd pair from part 1"
	echo "  in addition, the root directory and kernel options are specified"
	echo ""
	echo "  The benefits of this tool over direct isolinux use are: "
	echo "  - allows use of long names in the input making it easier to "
	echo "    maintain the iso images. The short names required by isolinux"
	echo "    are a maintenance problem"
	echo "  - reduction of duplication. In many cases the same kernel/initrd"
	echo "    pair is used for different setups. This avoids duplication that"
	echo "    would occur in a isolinux.cfg file"
	echo "  - reduction of errors. It is almost foolproof. If you have the "
	echo "    kernel, initrd image, root diractory, and kernel options then"
	echo "    you can boot a system. Much less error prone than direct isolinux"
	echo "    use."
	echo ""
	echo "  Cavaets:"
	echo "  This tool only exposes the bare minimum of what isolinux can do."
	echo "  However, it is really helpful for solving technical problems by"
	echo "  making it very easy to create a bootable USB or CD/DVD."
	echo ""
	echo "  Credits:"
	echo "  Thanks to the isolinux community for providing the excellent"
	echo "  isolinux tools"
  ) 1>&2
  exit 1
}

if [[ $# -ne 2 ]]
then
  printHelp
fi

XML="$1"
if [[ ! -f "$XML" || ! -r "$XML" ]]
then
  printHelp "'$XML' not found or not readable"
fi

OUTPUT="$2"

# validate the input

XSD_DIR=$( dirname $0 )/../xsd
XSD_BOOT=$XSD_DIR/bootspec.xsd

execute xmllint --noout --schema $XSD_BOOT $XML

#TARGET=target
export CONTENT=$TARGET/content
rm -rf $TARGET
mkdir -p $TARGET
mkdir -p $CONTENT

XSLDIR=$( dirname $0 )/../xsl
XSL_ISOLINUX=$XSLDIR/isolinux.xsl
XSL_GENKERNELS=$XSLDIR/genkernels.xsl

# copy isolinux files.

execute cp $ISOLINUX $CONTENT
execute cp $MENUC32 $CONTENT

# generate isolinux.cfg

execute xsltproc $XSL_ISOLINUX $XML > $CONTENT/isolinux.cfg


# generate the script to ciopy kernel and initrd

execute xsltproc --stringparam curdir $( dirname $XML ) $XSL_GENKERNELS $XML > $TARGET/genkernel.sh
execute chmod 755 $TARGET/genkernel.sh
execute $TARGET/genkernel.sh


( 
  cd "$CONTENT"
  execute mkisofs -o ../boot.iso -b isolinux.bin  -c boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table $( find . -type f )
  isohybrid ../boot.iso
)

execute cp $TARGET/boot.iso "$OUTPUT" 

echo "Image is on '$OUTPUT'"


rm -rf $TARGET