#! /bin/sh
#
# Set a default boot entry for GRUB, for the next boot only.
# Copyright (C) 2004,2009  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/>.

# Initialize some variables.
prefix=/usr
exec_prefix=/usr
bindir=${exec_prefix}/bin
sbindir=${exec_prefix}/sbin
sysconfdir="/etc"
PACKAGE_NAME=GRUB
PACKAGE_VERSION=2.12-1ubuntu7.3
datarootdir="/usr/share"
datadir="${datarootdir}"
if [ "x$pkgdatadir" = x ]; then
    pkgdatadir="${datadir}/grub"
fi

self=`basename $0`

grub_editenv=${bindir}/grub-editenv
grub_probe=${sbindir}/grub-probe
rootdir=
bootdir=
grubdir=`echo "/boot/grub" | sed 's,//*,/,g'`

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

. "${pkgdatadir}/grub-mkconfig_lib"

# Usage: usage
# Print the usage.
usage () {
    gettext_printf "Usage: %s [OPTION] MENU_ENTRY\n" "$self"
    gettext "Set the default boot menu entry for GRUB, for the next boot only."; echo
    print_option_help "-h, --help" "$(gettext "print this message and exit")"
    print_option_help "-V, --version" "$(gettext "print the version information and exit")"
    dirmsg="$(gettext_printf "expect GRUB images under the directory DIR/%s instead of the %s directory" "grub" "$grubdir")"
    print_option_help "--boot-directory=$(gettext "DIR")" "$dirmsg"
    echo
    gettext "MENU_ENTRY is a number, a menu item title or a menu item identifier. Please note that menu items in
submenus or sub-submenus require specifying the submenu components and then the
menu item component. The titles should be separated using the greater-than
character (>) with no extra spaces. Depending on your shell some characters including > may need escaping. More information about this is available
in the GRUB Manual in the section about the 'default' command. "; echo
    echo
    gettext "NOTE: In cases where GRUB cannot write to the environment block, such as when it is stored on an MDRAID or LVM device, the chosen boot menu entry will remain the default even after reboot. "; echo
    echo
    gettext "Report bugs to <bug-grub@gnu.org>."; echo
}

argument () {
  opt=$1
  shift

  if test $# -eq 0; then
      gettext_printf "%s: option requires an argument -- \`%s'\n" "$self" "$opt" 1>&2
      exit 1
  fi
  echo $1
}

# Check the arguments.
while test $# -gt 0
do
    option=$1
    shift

    case "$option" in
    -h | --help)
	usage
	exit 0 ;;
    -V | --version)
	echo "$self (${PACKAGE_NAME}) ${PACKAGE_VERSION}"
	exit 0 ;;

# Accept for compatibility
    --root-directory)
	rootdir=`argument $option "$@"`; shift ;;
    --root-directory=*)
	rootdir=`echo "$option" | sed 's/--root-directory=//'` ;;

    --boot-directory)
    bootdir=`argument $option "$@"`; shift;;
    --boot-directory=*)
    bootdir=`echo "$option" | sed 's/--boot-directory=//'` ;;

    -*)
	gettext_printf "Unrecognized option \`%s'\n" "$option" 1>&2
	usage
	exit 1
	;;
    *)
	if test "x$entry" != x; then
	    gettext "More than one menu entry?" 1>&2
	    echo >&2
	    usage
	    exit 1
	fi
	entry="${option}" ;;
    esac
done

if test "x$entry" = x; then
    gettext "Menu entry not specified." 1>&2
    echo >&2
    usage
    exit 1
fi

if [ -z "$bootdir" ]; then
    # Default bootdir if bootdir not initialized.
    bootdir=/boot

    if [ -n "$rootdir" ] ; then
        # Initialize bootdir if rootdir was initialized.
        bootdir=${rootdir}/boot
    fi
fi

grubdir=`echo "${bootdir}/grub" | sed 's,//*,/,g'`

abstractions=`$grub_probe --target=abstraction ${grubdir}/grubenv`
for abstraction in $abstractions; do
    case "$abstraction" in
	diskfilter | lvm)
	    gettext_printf "\nWARNING: Detected GRUB environment block on $abstraction device\n"
	    gettext_printf "%s will remain the default boot entry until manually cleared with:\n" "${entry}"
	    gettext_printf "    grub-editenv ${grubdir}/grubenv unset next_entry\n\n"
	    break
	    ;;
    esac
done

# Restore saved_entry if it was set by previous version
prev_saved_entry=`$grub_editenv ${grubdir}/grubenv list | sed -n 's/^prev_saved_entry=//p'`
if [ "$prev_saved_entry" ]; then
    $grub_editenv ${grubdir}/grubenv set saved_entry="$prev_saved_entry"
    $grub_editenv ${grubdir}/grubenv unset prev_saved_entry
fi

$grub_editenv ${grubdir}/grubenv set next_entry="$entry"

# Bye.
exit 0