#! /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.
transform="@program_transform_name@"

prefix=@prefix@
exec_prefix=@exec_prefix@
bindir=@bindir@
PACKAGE_NAME=@PACKAGE_NAME@
PACKAGE_VERSION=@PACKAGE_VERSION@

self=`basename $0`

grub_editenv=${bindir}/`echo grub-editenv | sed ${transform}`
rootdir=

# Usage: usage
# Print the usage.
usage () {
    cat <<EOF
Usage: $self [OPTION] entry
Set the default boot entry for GRUB, for the next boot only.

  -h, --help              print this message and exit
  -v, --version           print the version information and exit
  --root-directory=DIR    expect GRUB images under the directory DIR
                          instead of the root directory

ENTRY is a number or a menu item title.

Report bugs to <bug-grub@gnu.org>.
EOF
}

# Check the arguments.
for option in "$@"; do
    case "$option" in
    -h | --help)
	usage
	exit 0 ;;
    -v | --version)
	echo "$self (${PACKAGE_NAME}) ${PACKAGE_VERSION}"
	exit 0 ;;
    --root-directory=*)
	rootdir=`echo "$option" | sed 's/--root-directory=//'` ;;
    -*)
	echo "Unrecognized option \`$option'" 1>&2
	usage
	exit 1
	;;
    *)
	if test "x$entry" != x; then
	    echo "More than one entry?" 1>&2
	    usage
	    exit 1
	fi
	entry="${option}" ;;
    esac
done

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

# Initialize these directories here, since ROOTDIR was initialized.
case "$host_os" in
netbsd* | openbsd*)
    # Because /boot is used for the boot block in NetBSD and OpenBSD, use /grub
    # instead of /boot/grub.
    grub_prefix=`echo /grub | sed ${transform}`
    bootdir=${rootdir}
    ;;
*)
    # Use /boot/grub by default.
    bootdir=${rootdir}/boot
    ;;
esac

grubdir=${bootdir}/`echo grub | sed ${transform}`

prev_saved_entry=`$grub_editenv ${grubdir}/grubenv list | sed -n 's/^saved_entry=//p'`
if [ "$prev_saved_entry" ]; then
    $grub_editenv ${grubdir}/grubenv set prev_saved_entry="$prev_saved_entry"
else
    # We need some non-empty value for prev_saved_entry so that GRUB will
    # recognise that grub-reboot has been used and restore the previous
    # saved entry. "0" is the same as an empty value, i.e. the first menu
    # entry.
    $grub_editenv ${grubdir}/grubenv set prev_saved_entry=0
fi
$grub_editenv ${grubdir}/grubenv set saved_entry="$entry"

# Bye.
exit 0