This file is indexed.

/etc/grub.d/20_linux_xen is in grub-common 2.02~beta2-36ubuntu3.

This file is owned by root:root, with mode 0o755.

The actual contents of the file can be viewed below.

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#! /bin/sh
set -e

# grub-mkconfig helper script.
# Copyright (C) 2006,2007,2008,2009,2010  Free Software Foundation, Inc.
#
# GRUB is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# GRUB is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GRUB.  If not, see <http://www.gnu.org/licenses/>.

prefix="/usr"
exec_prefix="/usr"
datarootdir="/usr/share"

. "${datarootdir}/grub/grub-mkconfig_lib"

export TEXTDOMAIN=grub
export TEXTDOMAINDIR="${datarootdir}/locale"

CLASS="--class gnu-linux --class gnu --class os --class xen"
SUPPORTED_INITS="sysvinit:/lib/sysvinit/init systemd:/lib/systemd/systemd upstart:/sbin/upstart"

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|LC_ALL=C sed 's,[^[:alnum:]_],_,g') ${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/"`
    # We can't cope with devices loop-mounted from files here.
    case ${GRUB_DEVICE} in
      /dev/*) ;;
      *) exit 0 ;;
    esac
  ;;
esac

if [ "x${GRUB_DEVICE_UUID}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
    || ! test -e "/dev/disk/by-uuid/${GRUB_DEVICE_UUID}" \
    || uses_abstraction "${GRUB_DEVICE}" lvm; then
  LINUX_ROOT_DEVICE=${GRUB_DEVICE}
else
  LINUX_ROOT_DEVICE=UUID=${GRUB_DEVICE_UUID}
fi

# Allow overriding GRUB_CMDLINE_LINUX and GRUB_CMDLINE_LINUX_DEFAULT.
if [ "${GRUB_CMDLINE_LINUX_XEN_REPLACE}" ]; then
  GRUB_CMDLINE_LINUX="${GRUB_CMDLINE_LINUX_XEN_REPLACE}"
fi
if [ "${GRUB_CMDLINE_LINUX_XEN_REPLACE_DEFAULT}" ]; then
  GRUB_CMDLINE_LINUX_DEFAULT="${GRUB_CMDLINE_LINUX_XEN_REPLACE_DEFAULT}"
fi

case x"$GRUB_FS" in
    xbtrfs)
	rootsubvol="`make_system_path_relative_to_its_root /`"
	rootsubvol="${rootsubvol#/}"
	if [ "x${rootsubvol}" != x ]; then
	    GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol} ${GRUB_CMDLINE_LINUX}"
	fi;;
    xzfs)
	rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null || true`
	bootfs="`make_system_path_relative_to_its_root / | sed -e "s,@$,,"`"
	LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs}"
	;;
esac

title_correction_code=

linux_entry ()
{
  os="$1"
  version="$2"
  xen_version="$3"
  type="$4"
  args="$5"
  xen_args="$6"
  if [ -z "$boot_device_id" ]; then
      boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
  fi
  if [ x$type != xsimple ] ; then
      if [ x$type = xrecovery ] ; then
	  title="$(gettext_printf "%s, with Xen %s and Linux %s (%s)" "${os}" "${xen_version}" "${version}" "$(gettext "${GRUB_RECOVERY_TITLE}")")"
      elif [ "${type#init-}" != "$type" ] ; then
	  title="$(gettext_printf "%s, with Xen %s and Linux %s (%s)" "${os}" "${xen_version}" "${version}" "${type#init-}")"
      else
	  title="$(gettext_printf "%s, with Xen %s and Linux %s" "${os}" "${xen_version}" "${version}")"
      fi
      replacement_title="$(echo "Advanced options for ${OS}" | sed 's,>,>>,g')>$(echo "$title" | sed 's,>,>>,g')"
      if [ x"Xen ${xen_version}>$title" = x"$GRUB_ACTUAL_DEFAULT" ]; then
         quoted="$(echo "$GRUB_ACTUAL_DEFAULT" | grub_quote)"
         title_correction_code="${title_correction_code}if [ \"x\$default\" = '$quoted' ]; then default='$(echo "$replacement_title" | grub_quote)'; fi;"
         grub_warn "$(gettext_printf "Please don't use old title \`%s' for GRUB_DEFAULT, use \`%s' (for versions before 2.00) or \`%s' (for 2.00 or later)" "$GRUB_ACTUAL_DEFAULT" "$replacement_title" "gnulinux-advanced-$boot_device_id>gnulinux-$version-$type-$boot_device_id")"
      fi
      echo "menuentry '$(echo "$title" | grub_quote)' ${CLASS} \$menuentry_id_option 'xen-gnulinux-$version-$type-$boot_device_id' {" | sed "s/^/$submenu_indentation/"
  else
      title="$(gettext_printf "%s, with Xen hypervisor" "${os}")"
      echo "menuentry '$(echo "$title" | grub_quote)' ${CLASS} \$menuentry_id_option 'xen-gnulinux-simple-$boot_device_id' {" | sed "s/^/$submenu_indentation/"
  fi
  if [ x$type != xrecovery ] ; then
      save_default_entry | grub_add_tab | sed "s/^/$submenu_indentation/"
  fi

  if [ -z "${prepare_boot_cache}" ]; then
    prepare_boot_cache="$(prepare_grub_to_access_device ${GRUB_DEVICE_BOOT} | grub_add_tab)"
  fi
  printf '%s\n' "${prepare_boot_cache}" | sed "s/^/$submenu_indentation/"
  xmessage="$(gettext_printf "Loading Xen %s ..." ${xen_version})"
  lmessage="$(gettext_printf "Loading Linux %s ..." ${version})"
  sed "s/^/$submenu_indentation/" << EOF
	echo	'$(echo "$xmessage" | grub_quote)'
        if [ "\$grub_platform" = "pc" -o "\$grub_platform" = "" ]; then
            xen_rm_opts=
        else
            xen_rm_opts="no-real-mode edd=off"
        fi
	multiboot	${rel_xen_dirname}/${xen_basename} placeholder ${xen_args} \${xen_rm_opts}
	echo	'$(echo "$lmessage" | grub_quote)'
	module	${rel_dirname}/${basename} placeholder root=${linux_root_device_thisversion} ro ${args}
EOF
  if test -n "${initrd}" ; then
    # TRANSLATORS: ramdisk isn't identifier. Should be translated.
    message="$(gettext_printf "Loading initial ramdisk ...")"
    sed "s/^/$submenu_indentation/" << EOF
	echo	'$(echo "$message" | grub_quote)'
	module	--nounzip   ${rel_dirname}/${initrd}
EOF
  fi
  sed "s/^/$submenu_indentation/" << EOF
}
EOF
}

linux_list=`for i in /boot/vmlinu[xz]-* /vmlinu[xz]-* /boot/kernel-*; do
    if grub_file_is_not_garbage "$i"; then
    	basename=$(basename $i)
	version=$(echo $basename | sed -e "s,^[^0-9]*-,,g")
	dirname=$(dirname $i)
	config=
	for j in "${dirname}/config-${version}" "${dirname}/config-${alt_version}" "/etc/kernels/kernel-config-${version}" ; do
	    if test -e "${j}" ; then
		config="${j}"
		break
	    fi
	done
        if (grep -qx "CONFIG_XEN_DOM0=y" "${config}" 2> /dev/null || grep -qx "CONFIG_XEN_PRIVILEGED_GUEST=y" "${config}" 2> /dev/null); then echo -n "$i " ; fi
    fi
    done`
if [ "x${linux_list}" = "x" ] ; then
    exit 0
fi

file_is_not_sym () {
    case "$1" in
	*/xen-syms-*)
	    return 1;;
	*)
	    return 0;;
    esac
}

xen_list=`for i in /boot/xen*; do
        if grub_file_is_not_garbage "$i" && file_is_not_sym "$i" ; then echo -n "$i " ; fi
      done`
prepare_boot_cache=
boot_device_id=

title_correction_code=

machine=`uname -m`

case "$machine" in
    i?86) GENKERNEL_ARCH="x86" ;;
    mips|mips64) GENKERNEL_ARCH="mips" ;;
    mipsel|mips64el) GENKERNEL_ARCH="mipsel" ;;
    arm*) GENKERNEL_ARCH="arm" ;;
    *) GENKERNEL_ARCH="$machine" ;;
esac

# Extra indentation to add to menu entries in a submenu. We're not in a submenu
# yet, so it's empty. In a submenu it will be equal to '\t' (one tab).
submenu_indentation=""

is_top_level=true

while [ "x${xen_list}" != "x" ] ; do
    list="${linux_list}"
    current_xen=`version_find_latest $xen_list`
    xen_basename=`basename ${current_xen}`
    xen_dirname=`dirname ${current_xen}`
    rel_xen_dirname=`make_system_path_relative_to_its_root $xen_dirname`
    xen_version=`echo $xen_basename | sed -e "s,.gz$,,g;s,^xen-,,g"`
    if [ -z "$boot_device_id" ]; then
	boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
    fi
    if [ "x$is_top_level" != xtrue ]; then
	echo "	submenu '$(gettext_printf "Xen hypervisor, version %s" "${xen_version}" | grub_quote)' \$menuentry_id_option 'xen-hypervisor-$xen_version-$boot_device_id' {"
    fi
    while [ "x$list" != "x" ] ; do
	linux=`version_find_latest $list`
	gettext_printf "Found linux image: %s\n" "$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"`
	alt_version=`echo $version | sed -e "s,\.old$,,g"`
	linux_root_device_thisversion="${LINUX_ROOT_DEVICE}"

	initrd=
	for i in "initrd.img-${version}" "initrd-${version}.img" "initrd-${version}.gz" \
	   "initrd-${version}" "initramfs-${version}.img" \
	   "initrd.img-${alt_version}" "initrd-${alt_version}.img" \
	   "initrd-${alt_version}" "initramfs-${alt_version}.img" \
	   "initramfs-genkernel-${version}" \
	   "initramfs-genkernel-${alt_version}" \
	   "initramfs-genkernel-${GENKERNEL_ARCH}-${version}" \
	   "initramfs-genkernel-${GENKERNEL_ARCH}-${alt_version}" ; do
	    if test -e "${dirname}/${i}" ; then
		initrd="$i"
		break
	    fi
	done
	if test -n "${initrd}" ; then
	    gettext_printf "Found initrd image: %s\n" "${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

	if [ "x$is_top_level" = xtrue ] && [ "x${GRUB_DISABLE_SUBMENU}" != xy ]; then
	    linux_entry "${OS}" "${version}" "${xen_version}" simple \
		"${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}" "${GRUB_CMDLINE_XEN} ${GRUB_CMDLINE_XEN_DEFAULT}"

	    submenu_indentation="$grub_tab$grub_tab"
    
	    if [ -z "$boot_device_id" ]; then
		boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
	    fi
            # TRANSLATORS: %s is replaced with an OS name
	    echo "submenu '$(gettext_printf "Advanced options for %s (with Xen hypervisor)" "${OS}" | grub_quote)' \$menuentry_id_option 'gnulinux-advanced-$boot_device_id' {"
	echo "	submenu '$(gettext_printf "Xen hypervisor, version %s" "${xen_version}" | grub_quote)' \$menuentry_id_option 'xen-hypervisor-$xen_version-$boot_device_id' {"
	   is_top_level=false
	fi

	linux_entry "${OS}" "${version}" "${xen_version}" advanced \
	    "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}" "${GRUB_CMDLINE_XEN} ${GRUB_CMDLINE_XEN_DEFAULT}"
	for supported_init in ${SUPPORTED_INITS}; do
	    init_path="${supported_init#*:}"
	    if [ -x "${init_path}" ] && [ "$(readlink -f /sbin/init)" != "${init_path}" ]; then
		linux_entry "${OS}" "${version}" "${xen_version}" "init-${supported_init%%:*}" \
		    "${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT} init=${init_path}" "${GRUB_CMDLINE_XEN} ${GRUB_CMDLINE_XEN_DEFAULT}"

	    fi
	done
	if [ "x${GRUB_DISABLE_RECOVERY}" != "xtrue" ]; then
	    linux_entry "${OS}" "${version}" "${xen_version}" recovery \
		"single ${GRUB_CMDLINE_LINUX}" "${GRUB_CMDLINE_XEN}"
	fi

	list=`echo $list | tr ' ' '\n' | fgrep -vx "$linux" | tr '\n' ' '`
    done
    if [ x"$is_top_level" != xtrue ]; then
	echo '	}'
    fi
    xen_list=`echo $xen_list | tr ' ' '\n' | fgrep -vx "$current_xen" | tr '\n' ' '`
done

# If at least one kernel was found, then we need to
# add a closing '}' for the submenu command.
if [ x"$is_top_level" != xtrue ]; then
  echo '}'
fi

echo "$title_correction_code"