From 5945c2f8496cab51b64ed9bd35d494dc04b8e5a6 Mon Sep 17 00:00:00 2001
From: Andrey Borzenkov <arvidjaar@gmail.com>
Date: Mon, 6 May 2013 22:13:34 +0400
Subject: [PATCH]     Reimplement grub-reboot to not depend on saved_entry. Use
 next_entry     variable for one time boot menu entry.

---
 ChangeLog                |  5 +++++
 util/grub-reboot.in      | 17 ++++++-----------
 util/grub-set-default.in |  1 +
 util/grub.d/00_header.in | 14 +++++++++++++-
 4 files changed, 25 insertions(+), 12 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b79c57ae6..16c54048c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2013-05-06  Andrey Borzenkov <arvidjaar@gmail.com>
+
+	Reimplement grub-reboot to not depend on saved_entry. Use next_entry
+	variable for one time boot menu entry.
+
 2013-05-05  Bean  <bean123ch@gmail.com>
 
 	* grub-core/commands/testspeed.c: New command testspeed.
diff --git a/util/grub-reboot.in b/util/grub-reboot.in
index 1a91d369a..d132e4f30 100644
--- a/util/grub-reboot.in
+++ b/util/grub-reboot.in
@@ -46,8 +46,6 @@ export TEXTDOMAINDIR="@localedir@"
 usage () {
     gettext_printf "Usage: %s [OPTION] MENU_ENTRY\n" "$self"
     gettext "Set the default boot menu entry for GRUB, for the next boot only."; echo
-    gettext_printf "This requires setting GRUB_DEFAULT=saved in %s/default/grub.\n" "$sysconfdir"
-    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="$(gettext_printf "expect GRUB images under the directory DIR/%s instead of the %s directory" "@grubdirname@" "$grubdir")"
@@ -129,17 +127,14 @@ fi
 
 grubdir=`echo "${bootdir}/@grubdirname@" | sed 's,//*,/,g'`
 
-prev_saved_entry=`$grub_editenv ${grubdir}/grubenv list | sed -n 's/^saved_entry=//p'`
+# Restore saved_entry if it was set by previous version
+prev_saved_entry=`$grub_editenv ${grubdir}/grubenv list | sed -n 's/^prev_saved_entry=//p'`
 if [ "$prev_saved_entry" ]; then
-    $grub_editenv ${grubdir}/grubenv set prev_saved_entry="$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
+    $grub_editenv ${grubdir}/grubenv set saved_entry="$prev_saved_entry"
+    $grub_editenv ${grubdir}/grubenv unset prev_saved_entry
 fi
-$grub_editenv ${grubdir}/grubenv set saved_entry="$entry"
+
+$grub_editenv ${grubdir}/grubenv set next_entry="$entry"
 
 # Bye.
 exit 0
diff --git a/util/grub-set-default.in b/util/grub-set-default.in
index ea18da14f..d607318ed 100644
--- a/util/grub-set-default.in
+++ b/util/grub-set-default.in
@@ -130,6 +130,7 @@ fi
 grubdir=`echo "${bootdir}/@grubdirname@" | sed 's,//*,/,g'`
 
 $grub_editenv ${grubdir}/grubenv unset prev_saved_entry
+$grub_editenv ${grubdir}/grubenv unset next_entry
 $grub_editenv ${grubdir}/grubenv set saved_entry="$entry"
 
 # Bye.
diff --git a/util/grub.d/00_header.in b/util/grub.d/00_header.in
index 3da5d123f..2c4bb0a6f 100644
--- a/util/grub.d/00_header.in
+++ b/util/grub.d/00_header.in
@@ -51,13 +51,25 @@ if [ "x$GRUB_BUTTON_CMOS_ADDRESS" != "x" ]; then
     cat <<EOF
 if cmostest $GRUB_BUTTON_CMOS_ADDRESS ; then
    set default="${GRUB_DEFAULT_BUTTON}"
+elif [ "\${next_entry}" ] ; then
+   set default="\${next_entry}"
+   set next_entry=
+   save_env next_entry
+   set boot_once=true
 else
    set default="${GRUB_DEFAULT}"
 fi
 EOF
 else
     cat <<EOF
-set default="${GRUB_DEFAULT}"
+if [ "\${next_entry}" ] ; then
+   set default="\${next_entry}"
+   set next_entry=
+   save_env next_entry
+   set boot_once=true
+else
+   set default="${GRUB_DEFAULT}"
+fi
 EOF
 fi
 cat <<EOF