#! /bin/sh -e

if [ -f /usr/lib/grub/grub-mkconfig_lib ]; then
  . /usr/lib/grub/grub-mkconfig_lib
else
  # no grub file, so we notify and exit gracefully
  echo "Cannot find grub config file, exiting." >&2
  exit 0
fi

XEN_HYPERVISOR_CMDLINE="dom0_mem=512M"
XEN_LINUX_CMDLINE="console=tty0"

if [ -f /etc/default/grub ]; then
  . /etc/default/grub
fi

CLASS="--class gnu-linux --class gnu --class os"

if [ "x${GRUB_DISTRIBUTOR}" = "x" ] ; then
  OS=GNU/Linux
else
  OS="${GRUB_DISTRIBUTOR} GNU/Linux"
  CLASS="--class $(echo ${GRUB_DISTRIBUTOR} | tr '[A-Z]' '[a-z]' | cut -d' ' -f1) ${CLASS}"
fi

# loop-AES arranges things so that /dev/loop/X can be our root device, but
# the initrds that Linux uses don't like that.
case ${GRUB_DEVICE} in
  /dev/loop/*|/dev/loop[0-9])
    GRUB_DEVICE=`losetup ${GRUB_DEVICE} | sed -e "s/^[^(]*(\([^)]\+\)).*/\1/"`
  ;;
esac

if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
    || [ "`grub-probe -t abstraction --device ${GRUB_DEVICE} | sed -e 's,.*\(lvm\).*,\1,'`" = "lvm"  ] ; then
  LINUX_ROOT_DEVICE=${GRUB_DEVICE}
else
  LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
fi

xen_entry ()
{
  os="$1"
  xen_version="$2"
  version="$3"
  xen_args="$4"
  args="$5"
  recovery="$6"
  printf "menuentry '%s Xen %s, with Linux %s%s' --class xen ${CLASS} {\n" \
	  "${os}" "${xen_version}" "${version}" "${recovery}"
  save_default_entry | sed -e "s/^/\t/"

  if [ -z "${prepare_boot_cache}" ]; then
    prepare_boot_cache="$(prepare_grub_to_access_device ${GRUB_DEVICE_BOOT} | sed -e "s/^/\t/")"
  fi
  printf '%s\n' "${prepare_boot_cache}"
  cat << EOF
	echo '$(printf "Loading Xen hypervisor %s ..." ${xen_version})'
	multiboot ${rel_dirname}/${xen_basename} ${xen_args}
	echo $(printf "$(gettext "Loading Linux %s kernel ...")" ${version})
	module ${rel_dirname}/${basename} root=${linux_root_device_thisversion} ro ${args}
EOF
  if test -n "${initrd}" ; then
    cat << EOF
	echo "Loading initial ramdisk ..."
	module ${rel_dirname}/${initrd}
EOF
  fi
  cat << EOF
}
EOF
}

xen_list=`for i in /boot/xen-*.gz; do
       if grub_file_is_not_garbage "$i" && ! test -h "$i"; then echo -n "$i "; fi
done`
prepare_boot_cache=

while [ "x$xen_list" != "x" ] ; do
  xen=`version_find_latest $xen_list`
  echo "Found Xen hypervisor image: $xen" >&2
  xen_basename=`basename $xen`
  xen_dirname=`dirname $xen`
  rel_xen_dirname=`make_system_path_relative_to_its_root $xen_dirname`
  xen_version=`echo $xen_basename | sed -e "s,^[^0-9]*-,,g" | sed -e "s,.gz,,g"`
  alt_xen_version=`echo $xen_version | sed -e "s,\.old$,,g"`
  xen_configfiles=`grep -l 'CONFIG_XEN_PRIVILEGED_GUEST=y' /boot/config-*`

  for i in $xen_configfiles ; do
    i=`echo $i | sed -e "s,/boot/config-,/boot/vmlinuz-,g"`;
    if grub_file_is_not_garbage "$i"; then
      list="$list $i";
    fi
  done

  while [ "x$list" != "x" ] ; do
    linux=`version_find_latest $list`
    echo "Found linux image: $linux" >&2
    basename=`basename $linux`
    dirname=`dirname $linux`
    rel_dirname=`make_system_path_relative_to_its_root $dirname`
    version=`echo $basename | sed -e "s,^[^0-9]*-,,g"`
    linux_root_device_thisversion="${LINUX_ROOT_DEVICE}"
    initrd=

    for i in "initrd.img-${version}"; do
       if test -e "${dirname}/${i}" ; then
         initrd="$i"
         break
       fi
    done
    if test -n "${initrd}" ; then
      echo "Found initrd image: ${dirname}/${initrd}" >&2
    else
      # "UUID=" magic is parsed by initrds.  Since there's no initrd, it can't work here.
      linux_root_device_thisversion=${GRUB_DEVICE}
    fi

    xen_entry "${OS}" "${xen_version}" "${version}" \
	"${XEN_HYPERVISOR_CMDLINE}" "${GRUB_CMDLINE_LINUX_DEFAULT}"
    if [ "x${GRUB_DISABLE_LINUX_RECOVERY}" != "xtrue" ]; then
	xen_entry "${OS}" "${xen_version}" "${version}" \
	    "${XEN_HYPERVISOR_CMDLINE}" "single ${GRUB_CMDLINE_LINUX_DEFAULT}" \
	    " (recovery mode)"
    fi

    list=`echo $list | tr ' ' '\n' | grep -vx $linux | tr '\n' ' '`
  done

  xen_list=`echo $xen_list | tr ' ' '\n' | grep -vx $xen | tr '\n' ' '`
done