From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Peter Jones <pjones@redhat.com>
Date: Fri, 9 Dec 2016 15:40:29 -0500
Subject: [PATCH] Add BLS support to grub-mkconfig

GRUB now has BootLoaderSpec support, the user can choose to use this by
setting GRUB_ENABLE_BLSCFG to true in /etc/default/grub. On this setup,
the boot menu entries are not added to the grub.cfg, instead BLS config
files are parsed by blscfg command and the entries created dynamically.

A 10_linux_bls grub.d snippet to generate menu entries from BLS files
is also added that can be used on platforms where the bootloader doesn't
have BLS support and only can parse a normal grub configuration file.

Portions of the 10_linux_bls were taken from the ostree-grub-generator
script that's included in the OSTree project.

Fixes to support multi-devices and generate a BLS section even if no
kernels are found in the boot directory were proposed by Yclept Nemo
and Tom Gundersen respectively.

Signed-off-by: Peter Jones <pjones@redhat.com>
[javierm: remove outdated URL for BLS document]
Signed-off-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Robbie Harwood <rharwood@redhat.com>
---
 util/grub-mkconfig.8      |   4 +
 util/grub-mkconfig.in     |   9 +-
 util/grub-mkconfig_lib.in |  22 +++-
 util/grub.d/10_linux.in   | 222 +++++++++++++++++++++++++++++++++++++-
 4 files changed, 251 insertions(+), 6 deletions(-)

diff --git a/util/grub-mkconfig.8 b/util/grub-mkconfig.8
index a2d1f57..434fa4d 100644
--- a/util/grub-mkconfig.8
+++ b/util/grub-mkconfig.8
@@ -13,5 +13,9 @@
 \fB--output\fR=\fIFILE\fR
 Write generated output to \fIFILE\fR.
 
+.TP
+\fB--no-grubenv-update\fR
+Do not update variables in the grubenv file.
+
 .SH SEE ALSO
 .BR "info grub"
diff --git a/util/grub-mkconfig.in b/util/grub-mkconfig.in
index f939872..212bbcf 100644
--- a/util/grub-mkconfig.in
+++ b/util/grub-mkconfig.in
@@ -50,6 +50,8 @@ grub_get_kernel_settings="${sbindir}/@grub_get_kernel_settings@"
 export TEXTDOMAIN=@PACKAGE@
 export TEXTDOMAINDIR="@localedir@"
 
+export GRUB_GRUBENV_UPDATE="yes"
+
 . "${pkgdatadir}/grub-mkconfig_lib"
 
 # Usage: usage
@@ -59,6 +61,7 @@ usage () {
     gettext "Generate a grub config file"; echo
     echo
     print_option_help "-o, --output=$(gettext FILE)" "$(gettext "output generated config to FILE [default=stdout]")"
+    print_option_help "--no-grubenv-update" "$(gettext "do not update variables in the grubenv file")"
     print_option_help "-h, --help" "$(gettext "print this message and exit")"
     print_option_help "-V, --version" "$(gettext "print the version information and exit")"
     echo
@@ -94,6 +97,9 @@ do
     --output=*)
 	grub_cfg=`echo "$option" | sed 's/--output=//'`
 	;;
+    --no-grubenv-update)
+	GRUB_GRUBENV_UPDATE="no"
+	;;
     -*)
 	gettext_printf "Unrecognized option \`%s'\n" "$option" 1>&2
 	usage
@@ -305,7 +311,8 @@ export GRUB_DEFAULT \
   GRUB_DISABLE_SUBMENU \
   SUSE_BTRFS_SNAPSHOT_BOOTING \
   SUSE_CMDLINE_XENEFI \
-  SUSE_REMOVE_LINUX_ROOT_PARAM
+  SUSE_REMOVE_LINUX_ROOT_PARAM \
+  GRUB_ENABLE_BLSCFG
 
 if test "x${grub_cfg}" != "x"; then
   rm -f "${grub_cfg}.new"
diff --git a/util/grub-mkconfig_lib.in b/util/grub-mkconfig_lib.in
index 22fb766..5db4337 100644
--- a/util/grub-mkconfig_lib.in
+++ b/util/grub-mkconfig_lib.in
@@ -30,6 +30,9 @@ fi
 if test "x$grub_file" = x; then
   grub_file="${bindir}/@grub_file@"
 fi
+if test "x$grub_editenv" = x; then
+  grub_editenv="${bindir}/@grub_editenv@"
+fi
 if test "x$grub_mkrelpath" = x; then
   grub_mkrelpath="${bindir}/@grub_mkrelpath@"
 fi
@@ -123,8 +126,19 @@ EOF
   fi
 }
 
+prepare_grub_to_access_device_with_variable ()
+{
+  device_variable="$1"
+  shift
+  prepare_grub_to_access_device "$@"
+  unset "device_variable"
+}
+
 prepare_grub_to_access_device ()
 {
+  if [ -z "$device_variable" ]; then
+    device_variable="root"
+  fi
   old_ifs="$IFS"
   IFS='
 '
@@ -159,18 +173,18 @@ prepare_grub_to_access_device ()
   # otherwise set root as per value in device.map.
   fs_hint="`"${grub_probe}" --device $@ --target=compatibility_hint`"
   if [ "x$fs_hint" != x ]; then
-    echo "set root='$fs_hint'"
+    echo "set ${device_variable}='$fs_hint'"
   fi
   if [ "x${GRUB_DISABLE_UUID}" != "xtrue" ] && fs_uuid="`"${grub_probe}" --device $@ --target=fs_uuid 2> /dev/null`" ; then
     hints="`"${grub_probe}" --device $@ --target=hints_string 2> /dev/null`" || hints=
     if [ "x$hints" != x ]; then
       echo "if [ x\$feature_platform_search_hint = xy ]; then"
-      echo "  search --no-floppy --fs-uuid --set=root ${hints} ${fs_uuid}"
+      echo "  search --no-floppy --fs-uuid --set=${device_variable} ${hints} ${fs_uuid}"
       echo "else"
-      echo "  search --no-floppy --fs-uuid --set=root ${fs_uuid}"
+      echo "  search --no-floppy --fs-uuid --set=${device_variable} ${fs_uuid}"
       echo "fi"
     else
-      echo "search --no-floppy --fs-uuid --set=root ${fs_uuid}"
+      echo "search --no-floppy --fs-uuid --set=${device_variable} ${fs_uuid}"
     fi
   fi
   IFS="$old_ifs"
diff --git a/util/grub.d/10_linux.in b/util/grub.d/10_linux.in
index 467accb..af09e65 100644
--- a/util/grub.d/10_linux.in
+++ b/util/grub.d/10_linux.in
@@ -88,6 +88,223 @@ case x"$GRUB_FS" in
 	;;
 esac
 
+populate_header_warn()
+{
+if [ "x${BLS_POPULATE_MENU}" = "xtrue" ]; then
+  bls_parser="10_linux script"
+else
+  bls_parser="blscfg command"
+fi
+cat <<EOF
+
+# This section was generated by a script. Do not modify the generated file - all changes
+# will be lost the next time file is regenerated. Instead edit the BootLoaderSpec files.
+#
+# The $bls_parser parses the BootLoaderSpec files stored in /boot/loader/entries and
+# populates the boot menu. Please refer to the Boot Loader Specification documentation
+# for the files format: https://systemd.io/BOOT_LOADER_SPECIFICATION/.
+
+EOF
+}
+
+read_config()
+{
+    config_file=${1}
+    title=""
+    initrd=""
+    options=""
+    linux=""
+    grub_arg=""
+
+    while read -r line
+    do
+        record=$(echo ${line} | cut -f 1 -d ' ')
+        value=$(echo ${line} | cut -s -f2- -d ' ')
+        case "${record}" in
+            "title")
+                title=${value}
+                ;;
+            "initrd")
+                initrd=${value}
+                ;;
+            "linux")
+                linux=${value}
+                ;;
+            "options")
+                options=${value}
+                ;;
+            "grub_arg")
+                grub_arg=${value}
+                ;;
+        esac
+    done < ${config_file}
+}
+
+blsdir="/boot/loader/entries"
+
+get_sorted_bls()
+{
+    if ! [ -d "${blsdir}" ] || ! [ -e /etc/machine-id ]; then
+        return
+    fi
+
+    read machine_id < /etc/machine-id
+    if [ -z "${machine_id}" ]; then
+        return
+    fi
+
+    local IFS=$'\n'
+
+    files=($(for bls in ${blsdir}/${machine_id}-*.conf; do
+        if ! [[ -e "${bls}" ]] ; then
+            continue
+        fi
+        bls="${bls%.conf}"
+        bls="${bls##*/}"
+        echo "${bls}"
+    done | ${kernel_sort} 2>/dev/null | tac)) || :
+
+    echo "${files[@]}"
+}
+
+update_bls_cmdline()
+{
+    local cmdline="root=${LINUX_ROOT_DEVICE} ro ${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}"
+    local -a files=($(get_sorted_bls))
+
+    for bls in "${files[@]}"; do
+        local options="${cmdline}"
+        if [ -z "${bls##*debug*}" ]; then
+            options="${options} ${GRUB_CMDLINE_LINUX_DEBUG}"
+        fi
+        options="$(echo "${options}" | sed -e 's/\//\\\//g')"
+        sed -i -e "s/^options.*/options ${options}/" "${blsdir}/${bls}.conf"
+    done
+}
+
+populate_menu()
+{
+    local -a files=($(get_sorted_bls))
+
+    gettext_printf "Generating boot entries from BLS files...\n" >&2
+
+    for bls in "${files[@]}"; do
+        read_config "${blsdir}/${bls}.conf"
+
+        menu="${menu}menuentry '${title}' ${grub_arg} --id=${bls} {\n"
+        menu="${menu}\t linux ${linux} ${options}\n"
+        if [ -n "${initrd}" ] ; then
+            menu="${menu}\t initrd ${boot_prefix}${initrd}\n"
+        fi
+        menu="${menu}}\n\n"
+    done
+    # The printf command seems to be more reliable across shells for special character (\n, \t) evaluation
+    printf "$menu"
+}
+
+# Make BLS the default if GRUB_ENABLE_BLSCFG was not set and grubby is not installed.
+if [ -z "${GRUB_ENABLE_BLSCFG}" ] && [ -z "$(which new-kernel-pkg 2> /dev/null)" ]; then
+	  GRUB_ENABLE_BLSCFG="true"
+fi
+
+if [ "x${GRUB_ENABLE_BLSCFG}" = "xtrue" ]; then
+  if [ x$dirname = x/ ]; then
+    if [ -z "${prepare_root_cache}" ]; then
+      prepare_grub_to_access_device ${GRUB_DEVICE}
+    fi
+  else
+    if [ -z "${prepare_boot_cache}" ]; then
+      prepare_grub_to_access_device ${GRUB_DEVICE_BOOT}
+    fi
+  fi
+
+  if [ -d /sys/firmware/efi ]; then
+      bootefi_device="`${grub_probe} --target=device /boot/efi/`"
+      prepare_grub_to_access_device_with_variable boot ${bootefi_device}
+  else
+      boot_device="`${grub_probe} --target=device /boot/`"
+      prepare_grub_to_access_device_with_variable boot ${boot_device}
+  fi
+
+  arch="$(uname -m)"
+  if [ "x${arch}" = "xppc64le" ] && [ -d /sys/firmware/opal ]; then
+
+      BLS_POPULATE_MENU="true"
+      petitboot_path="/sys/firmware/devicetree/base/ibm,firmware-versions/petitboot"
+
+      if test -e ${petitboot_path}; then
+          read -r -d '' petitboot_version < ${petitboot_path}
+          petitboot_version="$(echo ${petitboot_version//v})"
+
+	  if test -n ${petitboot_version}; then
+              major_version="$(echo ${petitboot_version} | cut -d . -f1)"
+              minor_version="$(echo ${petitboot_version} | cut -d . -f2)"
+
+              re='^[0-9]+$'
+              if [[ $major_version =~ $re ]] && [[ $minor_version =~ $re ]] &&
+                 ([[ ${major_version} -gt 1 ]] ||
+                  [[ ${major_version} -eq 1 &&
+                     ${minor_version} -ge 8  ]]); then
+                  BLS_POPULATE_MENU="false"
+              fi
+          fi
+      fi
+  fi
+
+  populate_header_warn
+
+  cat << EOF
+# The kernelopts variable should be defined in the grubenv file. But to ensure that menu
+# entries populated from BootLoaderSpec files that use this variable work correctly even
+# without a grubenv file, define a fallback kernelopts variable if this has not been set.
+#
+# The kernelopts variable in the grubenv file can be modified using the grubby tool or by
+# executing the grub2-mkconfig tool. For the latter, the values of the GRUB_CMDLINE_LINUX
+# and GRUB_CMDLINE_LINUX_DEFAULT options from /etc/default/grub file are used to set both
+# the kernelopts variable in the grubenv file and the fallback kernelopts variable.
+if [ -z "\${kernelopts}" ]; then
+  set kernelopts="root=${LINUX_ROOT_DEVICE} ro ${GRUB_CMDLINE_LINUX} ${GRUB_CMDLINE_LINUX_DEFAULT}"
+fi
+EOF
+
+  update_bls_cmdline
+
+  if [ "x${BLS_POPULATE_MENU}" = "xtrue" ]; then
+      populate_menu
+  else
+      cat << EOF
+
+insmod blscfg
+blscfg
+EOF
+  fi
+
+  if [ "x${GRUB_GRUBENV_UPDATE}" = "xyes" ]; then
+      blsdir="/boot/loader/entries"
+      [ -d "${blsdir}" ] && GRUB_BLS_FS="$(${grub_probe} --target=fs ${blsdir})"
+      if [ "x${GRUB_BLS_FS}" = "xbtrfs" ] || [ "x${GRUB_BLS_FS}" = "xzfs" ]; then
+          blsdir=$(make_system_path_relative_to_its_root "${blsdir}")
+          if [ "x${blsdir}" != "x/loader/entries" ] && [ "x${blsdir}" != "x/boot/loader/entries" ]; then
+              ${grub_editenv} - set blsdir="${blsdir}"
+          fi
+      fi
+
+      if [ -n "${GRUB_EARLY_INITRD_LINUX_CUSTOM}" ]; then
+          ${grub_editenv} - set early_initrd="${GRUB_EARLY_INITRD_LINUX_CUSTOM}"
+      fi
+
+      if [ -n "${GRUB_DEFAULT_DTB}" ]; then
+          ${grub_editenv} - set devicetree="${GRUB_DEFAULT_DTB}"
+      fi
+
+      if [ -n "${GRUB_SAVEDEFAULT}" ]; then
+           ${grub_editenv} - set save_default="${GRUB_SAVEDEFAULT}"
+      fi
+  fi
+
+  exit 0
+fi
+
 mktitle ()
 {
   local title_type
@@ -152,6 +369,7 @@ linux_entry ()
   if [ -z "$boot_device_id" ]; then
       boot_device_id="$(grub_get_device_id "${GRUB_DEVICE}")"
   fi
+
   if [ x$type != xsimple ] ; then
       title=$(mktitle "$type" "$version")
       if [ x"$title" = x"$GRUB_ACTUAL_DEFAULT" ] || [ x"Previous Linux versions>$title" = x"$GRUB_ACTUAL_DEFAULT" ]; then
@@ -373,7 +591,9 @@ for linux in ${reverse_sorted_list}; do
     for i in ${initrd}; do
       initrd_display="${initrd_display} ${dirname}/${i}"
     done
-    gettext_printf "Found initrd image: %s\n" "$(echo $initrd_display)" >&2
+    if [ "x${GRUB_ENABLE_BLSCFG}" != "xtrue" ]; then
+      gettext_printf "Found initrd image: %s\n" "$(echo $initrd_display)" >&2
+    fi
   fi
 
   config=
-- 
2.43.0