From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Wed, 6 Jun 2018 08:44:11 +0200
Subject: [PATCH] Add auto-hide menu support

On single-os systems we do not want to show the menu, unless something
went wrong with the previous boot, in which case the user may need the
menu to debug/fix the problem.

This commit adds a new grub.d/00_menu_auto_hide file which emits a
config snippet implementing this. I've chosen to do this in a separate
grub.d file because chances of this going upstream are small and this way
it will be easier to rebase.

Since auto-hiding the menu requires detecting the previous boot was ok,
we get fastboot support (where we don't check for a key at all) for free
so this commit also adds support for this.

The new config-file code uses the following variables:

menu_auto_hide     Set this to "1" to activate the new auto-hide feature
                   Set this to "2" to auto-hide the menu even when multiple
                   operating systems are installed. Note the menu will still
                   auto show after booting an other os as that won't set
                   boot_success.
menu_show_once     Set this to "1" to force showing the menu once.
boot_success       The OS sets this to "1" to indicate a successful boot.
boot_indeterminate The OS increments this integer when rebooting after e.g.
                   installing updates or a selinux relabel.
fastboot           If set to "1" and the conditions for auto-hiding the menu
                   are met, the menu is not shown and all checks for keypresses
                   are skipped, booting the default immediately.

30_os-prober.in changes somewhat inspired by:
https://git.launchpad.net/~ubuntu-core-dev/grub/+git/ubuntu/tree/debian/patches/quick_boot.patch

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
 Makefile.util.def                |  6 +++++
 util/grub.d/01_menu_auto_hide.in | 48 ++++++++++++++++++++++++++++++++++++++++
 util/grub.d/30_os-prober.in      | 18 +++++++++++++++
 3 files changed, 72 insertions(+)
 create mode 100644 util/grub.d/01_menu_auto_hide.in

diff --git a/Makefile.util.def b/Makefile.util.def
index bda9fd1211..cb8e3c3270 100644
--- a/Makefile.util.def
+++ b/Makefile.util.def
@@ -458,6 +458,12 @@ script = {
   installdir = grubconf;
 };
 
+script = {
+  name = '01_menu_auto_hide';
+  common = util/grub.d/01_menu_auto_hide.in;
+  installdir = grubconf;
+};
+
 script = {
   name = '01_users';
   common = util/grub.d/01_users.in;
diff --git a/util/grub.d/01_menu_auto_hide.in b/util/grub.d/01_menu_auto_hide.in
new file mode 100644
index 0000000000..ad175870a5
--- /dev/null
+++ b/util/grub.d/01_menu_auto_hide.in
@@ -0,0 +1,48 @@
+#! /bin/sh
+
+# Disable / skip generating menu-auto-hide config parts on serial terminals
+for x in ${GRUB_TERMINAL_INPUT} ${GRUB_TERMINAL_OUTPUT}; do
+  case "$x" in
+    serial*)
+      exit 0
+      ;;
+  esac
+done
+
+cat << EOF
+if [ "\${boot_success}" = "1" -o "\${boot_indeterminate}" = "1" ]; then
+  set last_boot_ok=1
+else
+  set last_boot_ok=0
+fi
+
+# Reset boot_indeterminate after a successful boot
+if [ "\${boot_success}" = "1" ] ; then
+  set boot_indeterminate=0
+# Avoid boot_indeterminate causing the menu to be hidden more then once
+elif [ "\${boot_indeterminate}" = "1" ]; then
+  set boot_indeterminate=2
+fi
+set boot_success=0
+save_env boot_success boot_indeterminate
+
+if [ x\$feature_timeout_style = xy ] ; then
+  if [ "\${menu_show_once}" ]; then
+    unset menu_show_once
+    save_env menu_show_once
+    set timeout_style=menu
+    set timeout=60
+  elif [ "\${menu_auto_hide}" -a "\${last_boot_ok}" = "1" ]; then
+    set orig_timeout_style=\${timeout_style}
+    set orig_timeout=\${timeout}
+    if [ "\${fastboot}" = "1" ]; then
+      # timeout_style=menu + timeout=0 avoids the countdown code keypress check
+      set timeout_style=menu
+      set timeout=0
+    else
+      set timeout_style=hidden
+      set timeout=1
+    fi
+  fi
+fi
+EOF
diff --git a/util/grub.d/30_os-prober.in b/util/grub.d/30_os-prober.in
index 4b27bd2015..3c9431cfcf 100644
--- a/util/grub.d/30_os-prober.in
+++ b/util/grub.d/30_os-prober.in
@@ -42,6 +42,7 @@ if [ -z "${OSPROBED}" ] ; then
 fi
 
 osx_entry() {
+    found_other_os=1
     # TRANSLATORS: it refers on the OS residing on device %s
     onstr="$(gettext_printf "(on %s)" "${DEVICE}")"
     hints=""
@@ -102,6 +103,7 @@ for OS in ${OSPROBED} ; do
 
   case ${BOOT} in
     chain)
+      found_other_os=1
 
 	  onstr="$(gettext_printf "(on %s)" "${DEVICE}")"
       cat << EOF
@@ -132,6 +134,7 @@ EOF
 EOF
     ;;
     efi)
+      found_other_os=1
 
 	EFIPATH=${DEVICE#*@}
 	DEVICE=${DEVICE%@*}
@@ -176,6 +179,7 @@ EOF
 	  LINITRD="${LINITRD#/boot}"
 	fi
 
+        found_other_os=1
 	onstr="$(gettext_printf "(on %s)" "${DEVICE}")"
 	recovery_params="$(echo "${LPARAMS}" | grep single)" || true
 	counter=1
@@ -257,6 +261,7 @@ EOF
       done
     ;;
     hurd)
+      found_other_os=1
       onstr="$(gettext_printf "(on %s)" "${DEVICE}")"
       cat << EOF
 menuentry '$(echo "${LONGNAME} $onstr" | grub_quote)' --class hurd --class gnu --class os \$menuentry_id_option 'osprober-gnuhurd-/boot/gnumach.gz-false-$(grub_get_device_id "${DEVICE}")' {
@@ -283,6 +288,7 @@ EOF
 EOF
     ;;
     minix)
+      found_other_os=1
 	  cat << EOF
 menuentry "${LONGNAME} (on ${DEVICE}, Multiboot)" {
 EOF
@@ -299,3 +305,15 @@ EOF
     ;;
   esac
 done
+
+# We override the results of the menu_auto_hide code here, this is a bit ugly,
+# but grub-mkconfig writes out the file linearly, so this is the only way
+if [ "${found_other_os}" = "1" ]; then
+  cat << EOF
+# Other OS found, undo autohiding of menu unless menu_auto_hide=2
+if [ "\${orig_timeout_style}" -a "\${menu_auto_hide}" != "2" ]; then
+  set timeout_style=\${orig_timeout_style}
+  set timeout=\${orig_timeout}
+fi
+EOF
+fi