Fix indentation

My IDE was set up incorrectly. Convert all tab indentation to space.
Fix #116 (#118 )
2026-03-04 21:15:02 +08:00 · 2020-10-22 07:07:30 +02:00 · 2020-10-21 19:14:05 +02:00 · 2020-10-15 16:27:32 +02:00 · 2020-10-14 15:29:50 +02:00 · 2020-10-14 15:17:07 +02:00
10 changed files with 769 additions and 281 deletions
--- a/699
+++ b/699
@@ -1,295 +1,542 @@
 #! /usr/bin/env bash
 #
 #
-#################################################################################################################################################
-# Written by: Antynea																#
-#																		#
-# Purpose: Include btrfs snapshots at boot options (grub-menu).												#
-#																		#
-# What this script does:															#
-# - Automatically List snapshots existing on root partition (btrfs).										#
-# - Automatically Detect if "/boot" is in separate partition.											#
-# - Automatically Detect kernel, initramfs and intel microcode in "/boot" directory on snapshots. (For custon name, see below.)			#
-# - Automatically Create corresponding "menuentry" in grub.cfg , which ensures a very easy rollback.						#
-#																		#
-# How to use it:																#
-# - Add this lines to /etc/default/grub:													#
-#																		#
-# * GRUB_BTRFS_SUBMENUNAME="ArchLinux Snapshots" 												#
-#	(Name menu appearing in grub.)	 													#
-# * GRUB_BTRFS_PREFIXENTRY="Snapshot:"        		   											#
-#	(Add a name ahead your snapshots entries.) 												#
-# * GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="true"													#
-#	(Show full path snapshot or only name)													#
-# * GRUB_BTRFS_TITLE_FORMAT="p/d/n"														#
-#	(Custom title, shows/hides p"prefix" d"date" n"name" in grub-menu, separator "/", custom order available)				#
-# * GRUB_BTRFS_NKERNEL=("vmlinuz-linux") 		 											#
-#	(Use only if you have custom kernel name or auto-detect failed.)									#
-# * GRUB_BTRFS_NINIT=("initramfs-linux.img" "initramfs-linux-fallback.img")									#
-#	(Use only if you have custom initramfs name or auto-detect failed.)									#
-# * GRUB_BTRFS_INTEL_UCODE=("intel-ucode.img") 													#
-#	(Use only if you have custom intel-ucode or auto-detect failed.)									#
-#																		#
-# - Generate grub.cfg (on Archlinux use grub-mkconfig -o /boot/grub/grub.cfg)									#
-#																		#
-# - grub-btrfs automatically generates snapshots entries.											#
-# - You will see it appear different entries (e.g : Snapshot: [2014-02-12 11:24:37] my snapshot name overkill)					#
-#																		#
-#																		#
-# To do:																	#
-#																		#													#
-#	* Display name of microcode in menuentry when available											#
-#																		#
-#################################################################################################################################################
+# Written by: Antynea
+# BTC donation address: 1Lbvz244WA8xbpHek9W2Y12cakM6rDe5Rt
+# Github: https://github.com/Antynea/grub-btrfs
+#
+# Purpose:
+#   Improves Grub by adding "btrfs snapshots" to the Grub menu.
+#   You can start your system on a "snapshot" from the Grub menu.
+#   Supports manual snapshots, snapper ...
+#   Warning : booting on read-only snapshots can be tricky
+#   (Read about it, https://github.com/Antynea/grub-btrfs#warning-booting-on-read-only-snapshots-can-be-tricky)
+#
+# What this script does:
+# - Automatically List snapshots existing on root partition (btrfs).
+# - Automatically Detect if "/boot" is in separate partition.
+# - Automatically Detect kernel, initramfs and intel microcode in "/boot" directory on snapshots.
+# - Automatically Create corresponding "menuentry" in grub.cfg
+# - Automatically detect snapper and use snapper's snapshot description if available.
+# - Automatically generate grub.cfg if you use the provided systemd service.
+#
+# Installation:
+# - Run `make install` or look into Makefile for instructions on where to put each file.
+#
+# Customization:
+#  Refer to config for the list of available options and their default values.
+#  Place your configurations to /etc/default/grub-btrfs/config.
+#
+# Automatically update Grub
+#  If you would like Grub to automatically update when a snapshots is made or deleted:
+#  - Use systemctl start/enable grub-btrfs.path
+#  - grub-btrfs.path automatically (re)generates grub.cfg when a modification appears in /.snapshots folder (by default).
+#  - If your snapshots aren't mounted in /.snapshots, you must modify the watch folder using systemctl edit grub-btrfs.path
+#  - See https://github.com/Antynea/grub-btrfs#automatically-update-grub
+#
+# Special thanks for assistance and contributions:
+# - My friends
+# - All contributors on Github
+#

 set -e

-#prefix="/usr"
-#exec_prefix="${prefix}"
+prefix="/usr"
+exec_prefix="/usr"
 datarootdir="/usr/share"
-#datadir="${datarootdir}"
 sysconfdir="/etc"
+grub_btrfs_config="${sysconfdir}/default/grub-btrfs/config"

-. "${datarootdir}/grub/grub-mkconfig_lib"
+[[ -f "$grub_btrfs_config" ]] && . "$grub_btrfs_config"
+. "$datarootdir/grub/grub-mkconfig_lib"
 . "${sysconfdir}/default/grub"

-######################################
-### Variables in /etc/default/grub ###
-######################################
-## Choice of method
-choise_of_method=${GRUB_BTRFS_METHOD:-"1"}
+### Variables in /etc/default/grub-btrfs/config
+## Disable Grub-btrfs (default=active)
+[[ "${GRUB_BTRFS_DISABLE:-"false"}" == "true" ]] && exit 0
 ## Submenu name
-submenuname=${GRUB_BTRFS_SUBMENUNAME:-"ArchLinux Snapshots"}
+distro=$(awk -F "=" '/^NAME=/ {gsub(/"/, "", $2); print $2}' /etc/os-release)
+submenuname=${GRUB_BTRFS_SUBMENUNAME:-"${distro:-Linux} snapshots"}
 ## Prefix entry
 prefixentry=${GRUB_BTRFS_PREFIXENTRY:-"Snapshot:"}
-## Show full path snapshot or only name
-path_snapshot=${GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT:-"true"}
-## Title format
-title_format=${GRUB_BTRFS_TITLE_FORMAT:-"p/d/n"}
-## Kernel(s) name(s)
-nkernel=("${GRUB_BTRFS_NKERNEL[@]}")
-## Initramfs name(s)
-ninit=("${GRUB_BTRFS_NINIT[@]}")
-## Microcode(s) name(s)
-microcode=("${GRUB_BTRFS_INTEL_UCODE[@]}")
+## Limit snapshots to show in the Grub menu
+limit_snap_show="${GRUB_BTRFS_LIMIT:-50}"
+## How to sort snapshots list
+btrfssubvolsort=(--sort="${GRUB_BTRFS_SUBVOLUME_SORT:-"-rootid"}")
+## Snapper's config name
+snapper_config=${GRUB_BTRFS_SNAPPER_CONFIG:-"root"}
+## Customize GRUB directory, where "grub.cfg" file is saved
+grub_directory=${GRUB_BTRFS_GRUB_DIRNAME:-"/boot/grub"}
+## Customize BOOT directory, where kernels/initrams/microcode is saved.
+boot_directory=${GRUB_BTRFS_BOOT_DIRNAME:-"/boot"}
+## Password protection management for submenu
+# Protection support for submenu (--unrestricted)
+case "${GRUB_BTRFS_DISABLE_PROTECTION_SUBMENU:-"false"}" in
+    true)   unrestricted_access_submenu="--unrestricted ";;
+    *)      unrestricted_access_submenu=""
+esac
+# Authorized users (--users foo,bar)
+if [ ! -z "${GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS}" ] ; then
+    protection_authorized_users="--users ${GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS} "
+fi

-########################
-### variables script ###
-########################
-## Internationalization (default : english)
-export TEXTDOMAIN=grub-btrfs-git
-export TEXTDOMAINDIR="/usr/share/locale"
-## hints string
-hs_boot=$(${grub_probe} --target="hints_string" "/boot" 2>/dev/null)
-## UUID of the boot partition
-boot_uuid=$(${grub_probe} --target="fs_uuid" "/boot" 2>/dev/null)
-## Type filesystem of boot partition
-boot_fs=$(${grub_probe} --target="fs" "/boot" 2>/dev/null)
-## UUID of the root partition
-root_uuid=$(${grub_probe} "/" --target="fs_uuid" 2>/dev/null)
+### variables script
+## Probe info "Boot partition"
+# Boot device
+boot_device=$(${grub_probe} --target=device ${boot_directory})
+# hints string
+boot_hs=$(${grub_probe} --device ${boot_device} --target="hints_string" 2>/dev/null)
+# UUID of the boot partition
+boot_uuid=$(${grub_probe} --device ${boot_device} --target="fs_uuid" 2>/dev/null)
+# Type filesystem of boot partition
+boot_fs=$(${grub_probe} --device ${boot_device} --target="fs" 2>/dev/null)
+## Probe info "Root partition"
+# Type filesystem of root partition
+root_fs=$(${grub_probe} --target="fs" / 2>/dev/null)
+# Root device
+root_device=$(${grub_probe} --target=device /)
+# UUID of the root partition
+root_uuid=$(${grub_probe} --device ${root_device} --target="fs_uuid" 2>/dev/null)
 ## Parameters passed to the kernel
 kernel_parameters="$GRUB_CMDLINE_LINUX $GRUB_CMDLINE_LINUX_DEFAULT"
 ## Mount point location
-gbgmp="/tmp/gbgmp"
+gbgmp=$(mktemp -d)
 ## Class for theme
 CLASS="--class snapshots --class gnu-linux --class gnu --class os"
 ## save IFS
 oldIFS=$IFS
-## boot_dir (auto-detect if /boot is separate partition or not)
-boot_dir()
-{
-	boot_dir="$gbgmp/$snap_dir_name/boot"
-	[[ "$root_uuid" != "$boot_uuid" ]] && boot_dir="/boot"
-	echo "$boot_dir"
+## Detect uuid requirement (lvm,btrfs...)
+check_uuid_required() {
+if [ "x${root_uuid}" = "x" ] || [ "x${GRUB_DISABLE_LINUX_UUID}" = "xtrue" ] \
+    || ! test -e "/dev/disk/by-uuid/${root_uuid}" \
+    || ( test -e "${root_device}" && uses_abstraction "${root_device}" lvm ); then
+    LINUX_ROOT_DEVICE=${root_device}
+else
+    LINUX_ROOT_DEVICE=UUID=${root_uuid}
+fi
 }

+### Error Handling
+print_error()
+{
+    local arg="$@"
+    local nothing_to_do="If you think an error has occurred , please file a bug report at \" https://github.com/Antynea/grub-btrfs \"\nNothing to do. Abort.\n"
+    printf "${arg}\n${nothing_to_do}" >&2 ;
+    exit 0
+}

-##############
-### Script ###
-##############
+test_btrfs()
+{
+    [[ "$root_fs" != "btrfs" ]] && print_error "Root partition isn't a btrfs filesystem.\nThis script only supports snapshots of the btrfs filesystem."
+    set +e
+    type btrfs >/dev/null 2>&1
+    if [[ $? -ne 0 ]]; then
+        print_error "Unable to retrieve info from btrfs filesystem, make sure you have btrfs-progs on your system."
+    fi
+    set -e
+}

-### BEGIN auto detect ###
+### Script
+## Create entry
+entry()
+{
+echo "$@" >> "$grub_directory/grub-btrfs.cfg"
+}

 ## menu entries
-snapshots_entry()
+make_menu_entries()
 {
 ## \" required for snap,kernels,init,microcode with space in their name
-	echo "	submenu '"${title_menu[*]}"' {
-		submenu '---> "${title_menu[*]}" <---' { echo }
-	"
-	for k in "${name_kernel[@]}"; do
-		for i in "${name_initramfs[@]}"; do
-			for u in "${name_microcode[@]}"; do
-			echo "\
-		menuentry '"${k}" & "${i}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid'{
-			$(save_default_entry)
-			if [ x\$feature_all_video_module = xy ]; then
-				insmod all_video
-			fi
-			set gfxpayload=keep
-			insmod ${boot_fs}
-			if [ x\$feature_platform_search_hint = xy ]; then
-				search --no-floppy --fs-uuid  --set=root ${hs_boot} ${boot_uuid}
-			else
-				search --no-floppy --fs-uuid  --set=root ${boot_uuid}
-			fi
-			echo 'Loading Snapshot: "${snap_date_time}" "${snap_dir_name}"'
-			echo 'Loading Kernel: "${k}" ...'
-			linux \"${boot_dir_real_path}/"${k}"\" root=UUID=${root_uuid} rw rootflags=subvol=\""${snap_dir_name}"\" ${kernel_parameters}\
-			"
-			if [ -f "$(boot_dir)"/"${u}" ] ; then
-				echo "\
-			echo 'Loading Microcode & Initramfs: "${u}" "${i}" ...'
-			initrd \"${boot_dir_real_path}/"${u}"\" \"/"${snap_dir_name}"/boot/"${i}"\""
-			else
-				echo "\
-			echo 'Loading Initramfs: "${i}" ...'
-			initrd \"${boot_dir_real_path}/"${i}"\""
-			fi
-		echo "		}"
-			done
-		done
-	done
-	echo "	}"
+    entry "submenu '$title_menu' {
+    submenu '---> $title_menu <---' { echo }"
+    for k in "${name_kernel[@]}"; do
+        [[ ! -f "${boot_dir}"/"${k}" ]] && continue;
+        kversion=${k#*"-"}
+        for i in "${name_initramfs[@]}"; do
+            prefix_i=${i%%"-"*}
+            suffix_i=${i#*"-"}
+            alt_suffix_i=${i##*"-"}
+            if   [ "${kversion}" = "${suffix_i}" ];                 then i="${i}";
+            elif [ "${kversion}.img" = "${suffix_i}" ];             then i="${i}";
+            elif [ "${kversion}-fallback.img" = "${suffix_i}" ];    then i="${i}";
+            elif [ "${kversion}.gz" = "${suffix_i}" ];              then i="${i}";
+            else continue ;
+            fi
+            for u in "${name_microcode[@]}"; do
+                if [[ "${name_microcode}" != "x" ]] ; then
+                    entry "
+    menuentry '"${k}" & "${i}" & "${u}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid' {"
+                else
+                    entry "
+    menuentry '"${k}" & "${i}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid' {"
+                fi
+                entry "\
+        if [ x\$feature_all_video_module = xy ]; then
+        insmod all_video
+        fi
+        set gfxpayload=keep
+        insmod ${boot_fs}
+        if [ x\$feature_platform_search_hint = xy ]; then
+            search --no-floppy --fs-uuid  --set=root ${boot_hs} ${boot_uuid}
+        else
+            search --no-floppy --fs-uuid  --set=root ${boot_uuid}
+        fi
+        echo 'Loading Snapshot: "${snap_date_time}" "${snap_dir_name}"'
+        echo 'Loading Kernel: "${k}" ...'
+        linux \"${boot_dir_root_grub}/"${k}"\" root="${LINUX_ROOT_DEVICE}" rw ${kernel_parameters} rootflags=subvol=\""${snap_dir_name}"\""
+                if [[ "${name_microcode}" != "x" ]] ; then
+                    entry "\
+        echo 'Loading Microcode & Initramfs: "${u}" "${i}" ...'
+        initrd \"${boot_dir_root_grub}/"${u}"\" \"${boot_dir_root_grub}/"${i}"\""
+                else
+                    entry "\
+        echo 'Loading Initramfs: "${i}" ...'
+        initrd \"${boot_dir_root_grub}/"${i}"\""
+                fi
+                entry "    }"
+                count_warning_menuentries=$((1+$count_warning_menuentries))
+            done
+        done
+    done
+    entry  "}"
+}
+
+## Trim a string from leading and trailing whitespaces
+trim() {
+    local var="$*"
+    var="${var#"${var%%[![:space:]]*}"}"
+    var="${var%"${var##*[![:space:]]}"}"
+    echo -n "$var"
 }

 ## List of snapshots on filesystem
 snapshot_list()
 {
-	for snap in $(btrfs subvolume list -sa /); do
-		IFS=$oldIFS
-		snap=($snap)
-		local snap_path_name=${snap[@]:13:${#snap[@]}}
-		# Discard deleted snapshots
-		if [ "$snap_path_name" = "DELETED" ]; then continue; fi
-		[[ ${snap_path_name%%"/"*} == "<FS_TREE>" ]] && snap_path_name=${snap_path_name#*"/"}
-		echo ${snap[@]:10:2} ${snap_path_name}
-	done
+    # Query info from snapper if it is installed
+    type snapper >/dev/null 2>&1
+    if [ $? -eq 0 ]; then
+        if [ -s "/etc/snapper/configs/$snapper_config" ]; then
+            printf "Info: snapper detected, using config '$snapper_config'\n" >&2
+            local snapper_ids=($(snapper --no-dbus -t 0 -c "$snapper_config" list --disable-used-space | tail -n +3 | cut -d'|' -f 1))
+            local snapper_types=($(snapper --no-dbus -t 0 -c "$snapper_config" list --disable-used-space | tail -n +3 | cut -d'|' -f 2))
+
+            IFS=$'\n'
+            local snapper_descriptions=($(snapper --no-dbus -t 0 -c "$snapper_config" list --disable-used-space | tail -n +3 | rev | cut -d'|' -f 2 | rev))
+        else
+            printf "Warning: snapper detected but config '$snapper_config' does not exist\n" >&2
+        fi
+    fi
+
+    IFS=$'\n'
+
+    # Parse btrfs snapshots
+    local entries=()
+    local ids=()
+    local max_entry_length=0
+    for snap in $(btrfs subvolume list -sa "${btrfssubvolsort}" /); do
+        IFS=$oldIFS
+        snap=($snap)
+        local snap_path_name=${snap[@]:13:${#snap[@]}}
+
+        # Discard deleted snapshots
+        if [ "$snap_path_name" = "DELETED" ]; then continue; fi
+        [[ ${snap_path_name%%"/"*} == "<FS_TREE>" ]] && snap_path_name=${snap_path_name#*"/"}
+
+        # ignore specific path during run "grub-mkconfig"
+        if [ ! -z "${GRUB_BTRFS_IGNORE_SPECIFIC_PATH}" ] ; then
+            for isp in ${GRUB_BTRFS_IGNORE_SPECIFIC_PATH[@]} ; do
+                [[ "${snap_path_name}" == "${isp}" ]] && continue 2;
+            done
+        fi
+        if [ ! -z "${GRUB_BTRFS_IGNORE_PREFIX_PATH}" ] ; then
+            for isp in ${GRUB_BTRFS_IGNORE_PREFIX_PATH[@]} ; do
+                [[ "${snap_path_name}" == "${isp}"/* ]] && continue 2;
+            done
+        fi
+
+        # detect if /boot directory exists
+        [[ ! -d "$gbgmp/$snap_path_name/boot" ]] && continue;
+
+        local id="${snap_path_name//[!0-9]}" # brutal way to get id: remove everything non-numeric
+        ids+=("$id")
+
+        local entry="${snap[@]:10:2} | ${snap_path_name}"
+        entries+=("$entry")
+
+        # Find max length of a snapshot entry, needed for pretty formatting
+        local length="${#entry}"
+        [[ "$length" -gt "$max_entry_length" ]] && max_entry_length=$length
+    done
+
+    # Find max length of a snapshot type, needed for pretty formatting
+    local max_type_length=0
+    for id in "${ids[@]}"; do
+        for j in "${!snapper_ids[@]}"; do
+            local snapper_id="${snapper_ids[$j]//[[:space:]]/}"
+            if [[ "$snapper_id" == "$id" ]]; then
+                local snapper_type=$(trim "${snapper_types[$j]}")
+                local length="${#snapper_type}"
+                [[ "$length" -gt "$max_type_length" ]] && max_type_length=$length
+            fi
+        done
+    done
+
+    for i in "${!entries[@]}"; do
+        local id="${ids[$i]}"
+        local entry="${entries[$i]}"
+        for j in "${!snapper_ids[@]}"; do
+            local snapper_id="${snapper_ids[$j]//[[:space:]]/}"
+            # remove other non numeric characters
+            snapper_id="${snapper_id//\*/}"
+            snapper_id="${snapper_id//\+/}"
+            snapper_id="${snapper_id//-/}"
+            if [[ "$snapper_id" == "$id" ]]; then
+                local snapper_type=$(trim "${snapper_types[$j]}")
+                local snapper_description=$(trim "${snapper_descriptions[$j]}")
+                printf -v entry "%-${max_entry_length}s | %-${max_type_length}s | %s" "$entry" "$snapper_type" "$snapper_description"
+                break
+            fi
+        done
+        echo "$entry"
+    done
+
+    IFS=$oldIFS
 }

 ## Detect kernels in "/boot"
 detect_kernel()
 {
-	## Arch original kernel (auto-detect)
-	for akernel in "$(boot_dir)"/vmlinuz-* ; do 
-		list_kernel+=("$akernel")
-	done
+    list_kernel=()
+    # Original kernel (auto-detect)
+    for okernel in  "${boot_dir}"/vmlinuz-* \
+                    "${boot_dir}"/vmlinux-* \
+                    "${boot_dir}"/kernel-* ; do
+        [[ ! -f "${okernel}" ]] && continue;
+        list_kernel+=("$okernel")
+    done

-	## Custom name kernel in GRUB_BTRFS_NKERNEL
-	if [ ! -z "${nkernel}" ] ; then
-		for ckernel in "${nkernel[@]}" ; do
-			[[ ! -f /"$(boot_dir)"/"${ckernel}" ]] && continue;
-			list_kernel+=("$ckernel")
-		done
-	fi
+    # Custom name kernel in GRUB_BTRFS_NKERNEL
+    if [ ! -z "${GRUB_BTRFS_NKERNEL}" ] ; then
+        for ckernel in "${boot_dir}/${GRUB_BTRFS_NKERNEL[@]}" ; do
+            [[ ! -f "${ckernel}" ]] && continue;
+            list_kernel+=("$ckernel")
+        done
+    fi
 }

 ## Detect initramfs in "/boot"
 detect_initramfs()
 {
-	## Arch original initramfs (auto-detect)
-	for ainitramfs in "$(boot_dir)"/initramfs-* ; do 
-		list_initramfs+=("$ainitramfs")
-	done
-	
-	## Custom name initramfs in GRUB_BTRFS_NINIT
-	if [ ! -z "$ninit" ] ; then
-		for cinitramfs in "${ninit[@]}" ; do
-			[[ ! -f /"$(boot_dir)"/"${cinitramfs}" ]] && continue;
-			list_initramfs+=("$cinitramfs")
-		done
-	fi
+    list_initramfs=()
+    # Original initramfs (auto-detect)
+    for oinitramfs in   "${boot_dir}"/initrd.img-* \
+                        "${boot_dir}"/initrd-*.img \
+                        "${boot_dir}"/initrd-*.gz \
+                        "${boot_dir}"/initramfs-*.img \
+                        "${boot_dir}"/initramfs-*.gz ; do
+        [[ ! -f "${oinitramfs}" ]] && continue;
+        list_initramfs+=("$oinitramfs")
+    done
+
+    # Custom name initramfs in GRUB_BTRFS_NINIT
+    if [ ! -z "${GRUB_BTRFS_NINIT}" ] ; then
+        for cinitramfs in "${boot_dir}/${GRUB_BTRFS_NINIT[@]}" ; do
+            [[ ! -f "${cinitramfs}" ]] && continue;
+            list_initramfs+=("$cinitramfs")
+        done
+    fi
 }

 ## Detect microcode in "/boot"
 detect_microcode()
 {
-	## Arch original intel microcode
-	for aucode in "$(boot_dir)"/intel-ucode.img ; do
-		list_ucode+=("$aucode")
-	done
+    list_ucode=()
+    # Original intel/amd microcode (auto-detect)
+    # See "https://www.gnu.org/software/grub/manual/grub/html_node/Simple-configuration.html"
+    for oiucode in  "${boot_dir}"/intel-uc.img \
+                    "${boot_dir}"/intel-ucode.img \
+                    "${boot_dir}"/amd-uc.img \
+                    "${boot_dir}"/amd-ucode.img \
+                    "${boot_dir}"/early_ucode.cpio \
+                    "${boot_dir}"/microcode.cpio; do
+        [[ ! -f "${oiucode}" ]] && continue;
+        list_ucode+=("$oiucode")
+    done

-	## Custom name microcode in GRUB_BTRFS_INTEL_UCODE
-	if [ ! -z "$microcode" ] ; then
-		for cucode in "${microcode[@]}" ; do
-			[[ ! -f /"$(boot_dir)"/"${cucode}" ]] && continue
-			list_ucode+=("$cucode")
-		done
-	fi
+    # Custom name microcode in GRUB_BTRFS_CUSTOM_MICROCODE
+    if [ ! -z "${GRUB_BTRFS_CUSTOM_MICROCODE}" ] ; then
+        for cucode in "${boot_dir}/${GRUB_BTRFS_CUSTOM_MICROCODE[@]}" ; do
+            [[ ! -f "${cucode}" ]] && continue
+            list_ucode+=("$cucode")
+        done
+    fi
+    if [ -z "${list_ucode}" ]; then list_ucode=(x); fi
 }

 ## Show full path snapshot or only name
 path_snapshot()
 {
-	case "${path_snapshot}" in
-		true) name_snapshot=("${snap_dir_name}");;
-		*) name_snapshot=("${snap_dir_name#*"/"}")
-	esac
+    case "${GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT:-"true"}" in
+        true) name_snapshot=("${snap_full_name}");;
+        *)    name_snapshot=("${snap_full_name#*"/"}")
+    esac
 }

-
 ## Title format in grub-menu
 title_format()
 {
-	case "${title_format}" in
-		p/d/n) 	title_menu=("${prefixentry}" "${snap_date_time}" "${name_snapshot}");;
-		p/n/d) 	title_menu=("${prefixentry}" "${snap_dir_name}" "${snap_date_time}");;
-		p/d) 	title_menu=("${prefixentry}" "${snap_date_time}");;
-		p/n) 	title_menu=("${prefixentry}" "${snap_dir_name}");;
-		d/n) 	title_menu=("${snap_date_time}" "${snap_dir_name}");;
-		n/d) 	title_menu=("${snap_dir_name}" "${snap_date_time}");;
-		p) 	title_menu=("${prefixentry}");;
-		d)	title_menu=("${snap_date_time}");;
-		n)	title_menu=("${snap_dir_name}");;
-		*)	gettext_printf $"# Warning: GRUB_BTRFS_TITLE_FORMAT=${title_format}, syntax error \n" >&2
-	esac
+    case "${GRUB_BTRFS_TITLE_FORMAT:-"p/d/n"}" in
+        p/n/d)  title_menu="${prefixentry} ${name_snapshot} ${snap_date_time}";;
+        p/d)    title_menu="${prefixentry} ${snap_date_time}";;
+        p/n)    title_menu="${prefixentry} ${name_snapshot}";;
+        d/n)    title_menu="${snap_date_time} ${name_snapshot}";;
+        n/d)    title_menu="${name_snapshot} ${snap_date_time}";;
+        p)      title_menu="${prefixentry}";;
+        d)      title_menu="${snap_date_time}";;
+        n)      title_menu="${name_snapshot}";;
+        *)      title_menu="${prefixentry} ${snap_date_time} ${name_snapshot}"
+    esac
 }

 ## List of kernels, initramfs and microcode in snapshots
-list_kernels_initramfs()
+boot_bounded()
 {
-	IFS=$'\n'
-	for item in $(snapshot_list); do
-		IFS=$oldIFS
-		item=($item)
-		snap_dir_name=${item[@]:2:${#item[@]}}
-		[[ ! -d "$gbgmp/$snap_dir_name/boot" ]] && continue;
-		snap_date_time=${item[@]:0:2}
-		gettext_printf $"# Found Snapshot: %s\n" "${snap_date_time} ${snap_dir_name}" >&2 ;
-		unset list_kernel
-		detect_kernel
-		name_kernel=("${list_kernel[@]##*"/"}")
-		# echo "kernel = ${name_kernel[*]}"
-		unset list_initramfs
-		detect_initramfs
-		name_initramfs=("${list_initramfs[@]##*"/"}")
-		# echo "initramfs = ${name_initramfs[*]}"
-		unset list_ucode
-		detect_microcode
-		name_microcode=("${list_ucode[@]##*"/"}")
-		# echo "ucode = ${name_microcode[*]}"
-		boot_dir_real_path="$(make_system_path_relative_to_its_root "$(boot_dir)")"
-		## Create menu entries
-		# name snpashot
-		path_snapshot
-		# title menu custom
-		title_format
-		# echo "${title_menu[*]}"
-		snapshots_entry
-	done
-	IFS=$oldIFS
+    # Initialize menu entries
+    IFS=$'\n'
+    for item in $(snapshot_list); do
+        [[ ${limit_snap_show} -le 0 ]] && break; # fix: limit_snap_show=0
+        IFS=$oldIFS
+        snap_full_name="$(echo "$item" | cut -d'|' -f2-)" # do not trim it to keep nice formatting
+        snap_dir_name="$(echo "$item" | cut -d'|' -f2)"
+        snap_dir_name="$(trim "$snap_dir_name")"
+        snap_date_time="$(echo "$item" | cut -d' ' -f1-2)"
+        snap_date_time="$(trim "$snap_date_time")"
+        
+        boot_dir="$gbgmp/$snap_dir_name$boot_directory"
+        # Kernel (Original + custom kernel)
+        detect_kernel
+        if [ -z "${list_kernel}" ]; then continue; fi
+        name_kernel=("${list_kernel[@]##*"/"}")
+        # Initramfs (Original + custom initramfs)
+        detect_initramfs
+        if [ -z "${list_initramfs}" ]; then continue; fi
+        name_initramfs=("${list_initramfs[@]##*"/"}")
+        # microcode (auto-detect + custom microcode)
+        detect_microcode
+        name_microcode=("${list_ucode[@]##*"/"}")
+        # show snapshot found during run "grub-mkconfig"
+        if [[ "${GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND:-"true"}" = "true" ]]; then
+            printf "Found snapshot: %s\n" "$item" >&2 ;
+        fi
+        # Show full path snapshot or only name
+        path_snapshot
+        # Title format in grub-menu
+        title_format
+        # convert /boot directory to root of GRUB (e.g /boot become /)
+        boot_dir_root_grub="$(make_system_path_relative_to_its_root "${boot_dir}")"
+        # Make menuentries
+        make_menu_entries
+        ### Limit snapshots found during run "grub-mkconfig"
+        count_limit_snap=$((1+$count_limit_snap))
+        [[ $count_limit_snap -ge $limit_snap_show ]] && break;
+        # Limit generation of menuentries if exceeds 250
+        # [[ $count_warning_menuentries -ge 250 ]] && break;
+    done
+    IFS=$oldIFS
 }
-### END auto detect ###
+boot_separate()
+{
+    boot_dir="${boot_directory}"
+    # convert /boot directory to root of GRUB (e.g /boot become /)
+    boot_dir_root_grub="$(make_system_path_relative_to_its_root "${boot_dir}")"

-### Choice of method ###
-if [ ${choise_of_method} = "1" ] ; then 
-	gettext_printf "###### - Grub-btrfs: Auto-detect - ######\n" >&2 ;
-	[[ ! -d $gbgmp ]] && mkdir -p $gbgmp
-	mount -o subvolid=0 /dev/disk/by-uuid/$root_uuid $gbgmp/
-	echo "submenu '${submenuname}' {"
-	list_kernels_initramfs ;
-	echo "}"
-	umount $gbgmp
-	gettext_printf "###### - Grub-btrfs: Auto-detect - ######\n" >&2 ;
+    # Kernel (Original + custom kernel)
+    detect_kernel
+    if [ -z "${list_kernel}" ]; then print_error "Kernels not found."; fi
+    name_kernel=("${list_kernel[@]##*"/"}")
+    # Initramfs (Original + custom initramfs)
+    detect_initramfs
+    if [ -z "${list_initramfs}" ]; then print_error "Initramfs not found."; fi
+    name_initramfs=("${list_initramfs[@]##*"/"}")
+    # microcode (auto-detect + custom microcode)
+    detect_microcode
+    name_microcode=("${list_ucode[@]##*"/"}")
+
+    # Initialize menu entries
+    IFS=$'\n'
+    for item in $(snapshot_list); do
+        [[ ${limit_snap_show} -le 0 ]] && break; # fix: limit_snap_show=0
+        IFS=$oldIFS
+        snap_full_name="$(echo "$item" | cut -d'|' -f2-)" # do not trim it to keep nice formatting
+        snap_dir_name="$(echo "$item" | cut -d'|' -f2)"
+        snap_dir_name="$(trim "$snap_dir_name")"
+        snap_date_time="$(echo "$item" | cut -d' ' -f1-2)"
+        snap_date_time="$(trim "$snap_date_time")"
+        # show snapshot found during run "grub-mkconfig"
+        if [[ "${GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND:-"true"}" = "true" ]]; then
+            printf "Found snapshot: %s\n" "$item" >&2 ;
+        fi
+        # Show full path snapshot or only name
+        path_snapshot
+        # Title format in grub-menu
+        title_format
+        # Make menuentries
+        make_menu_entries
+        # Limit snapshots found during run "grub-mkconfig"
+        count_limit_snap=$((1+$count_limit_snap))
+        [[ $count_limit_snap -ge $limit_snap_show ]] && break;
+        # Limit generation of menuentries if exceeds 250
+        # [[ $count_warning_menuentries -ge 250 ]] && break;
+    done
+    IFS=$oldIFS
+}
+
+### Start
+printf "Detecting snapshots ...\n" >&2 ;
+# Only support btrfs snapshots
+test_btrfs
+# Delete existing config
+#rm -f --preserve-root "$grub_directory/grub-btrfs.cfg"
+> "$grub_directory/grub-btrfs.cfg"
+# Create mount point then mounting
+[[ ! -d $gbgmp ]] && mkdir -p $gbgmp
+mount -o subvolid=5 /dev/disk/by-uuid/$root_uuid $gbgmp/
+# Count menuentries
+count_warning_menuentries=0
+# Count snapshots
+count_limit_snap=0
+# detect uuid requirement
+check_uuid_required
+# Detects if /boot is a separate partition
+if [[ "${GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION:-"false"}" == "true" ]]; then
+    printf "Info: Override boot partition detection : enable \n" >&2 ;
+    boot_separate
+else
+    if [[ "$root_uuid" != "$boot_uuid" ]]; then
+        printf "Info: Separate boot partition detected \n" >&2 ;
+        boot_separate
+    else
+        printf "Info: Separate boot partition not detected \n" >&2 ;
+        boot_bounded
+    fi
 fi
-### End choice of method ###
+# unmounting mount point
+umount $gbgmp
+# Show warn, menuentries exceeds 250 entries
+[[ $count_warning_menuentries -ge 250 ]] && printf "Generated ${count_warning_menuentries} total GRUB entries. You might experience issues loading snapshots menu in GRUB.\n" >&2 ;
+# printf "menuentries = $count_warning_menuentries \n" >&2 ;
+# Show total found snapshots
+if [[ "${GRUB_BTRFS_SHOW_TOTAL_SNAPSHOTS_FOUND:-"true"}" = "true" && ! -z "${count_limit_snap}" && "${count_limit_snap}" != "0" ]]; then
+    printf "Found ${count_limit_snap} snapshot(s)\n" >&2 ;
+fi
+# if no snapshot found, exit
+if [[ "${count_limit_snap}" = "0" || -z "${count_limit_snap}" ]]; then
+    print_error "No snapshots found."
+fi
+# Make a submenu in GRUB (grub.cfg)
+cat << EOF
+submenu '${submenuname}' ${protection_authorized_users}${unrestricted_access_submenu}{
+    configfile "\${prefix}/grub-btrfs.cfg"
+}
+EOF
+### End
--- a/31
+++ b/31
@@ -0,0 +1,31 @@
+PKGNAME ?= grub-btrfs
+PREFIX ?= /usr
+
+SHARE_DIR = $(DESTDIR)$(PREFIX)/share
+LIB_DIR = $(DESTDIR)$(PREFIX)/lib
+
+.PHONY: install
+
+install:
+	@install -Dm755 -t "$(DESTDIR)/etc/grub.d/" 41_snapshots-btrfs
+	@install -Dm644 -t "$(DESTDIR)/etc/default/grub-btrfs/" config
+	@install -Dm644 -t "$(LIB_DIR)/systemd/system/" grub-btrfs.service
+	@install -Dm644 -t "$(LIB_DIR)/systemd/system/" grub-btrfs.path
+	@install -Dm644 -t "$(SHARE_DIR)/licenses/$(PKGNAME)/" LICENSE
+	@install -Dm644 "initramfs/Arch Linux/overlay_snap_ro-install" "$(LIB_DIR)/initcpio/install/grub-btrfs-overlayfs"	# Arch Linux only
+	@install -Dm644 "initramfs/Arch Linux/overlay_snap_ro-install" "$(LIB_DIR)/initcpio/install/grub-btrfs-overlayfs"	# Arch Linux only
+	@install -Dm644 -t "$(SHARE_DIR)/doc/$(PKGNAME)/" README.md
+	@install -Dm644 "initramfs/readme.md" "$(SHARE_DIR)/doc/$(PKGNAME)/initramfs-overlayfs.md"
+
+uninstall:
+	rm -f "$(DESTDIR)/etc/grub.d/41_snapshots-btrfs"
+	rm -f "$(DESTDIR)/etc/default/grub-btrfs/config"
+	rm -f "$(LIB_DIR)/systemd/system/grub-btrfs.service"
+	rm -f "$(LIB_DIR)/systemd/system/grub-btrfs.path"
+	rm -f "$(SHARE_DIR)/licenses/$(PKGNAME)/LICENSE"
+	rm -f "$(DESTDIR)/boot/grub/grub-btrfs.cfg"
+	rm -f "$(LIB_DIR)/initcpio/install/grub-btrfs-overlayfs" # Arch Linux only
+	rm -f "$(LIB_DIR)/initcpio/hooks/grub-btrfs-overlayfs" # Arch Linux only
+	rm -rf "$(SHARE_DIR)/doc/$(PKGNAME)/" README.md
+	rm -rf "$(SHARE_DIR)/doc/$(PKGNAME)/initramfs-overlayfs.md"
+	rmdir --ignore-fail-on-non-empty "$(DESTDIR)/etc/default/grub-btrfs"
--- a/README.md
+++ b/README.md
@@ -1,73 +1,75 @@
-[![GitHub release](https://img.shields.io/github/release/Antynea/grub-btrfs.svg)](https://github.com/Antynea/grub-btrfs)
-  
-### grub-btrfs
+[![GitHub release](https://img.shields.io/github/release/Antynea/grub-btrfs.svg)](https://github.com/Antynea/grub-btrfs/releases)
+![](https://img.shields.io/github/license/Antynea/grub-btrfs.svg)

+## grub-btrfs

-This is a version 1.xx of grub-btrfs
+This is a version 4.xx of grub-btrfs
+##### BTC donation address: `1Lbvz244WA8xbpHek9W2Y12cakM6rDe5Rt`
+##
+### Description
+Improves Grub by adding "btrfs snapshots" to the Grub menu.

-#### Description
+You can start your system on a "snapshot" from the Grub menu.  
+Supports manual snapshots, snapper, timeshift ...

-grub-btrfs, Include btrfs snapshots at boot options. (grub menu)
+##### Warning: booting on read-only snapshots can be tricky

-#### What does grub-btrfs v1.xx do :
+If you choose to do it, `/var/log` or even `/var` must be on a separate subvolume.  
+Otherwise, make sure your snapshots are writeable.  
+See [this ticket](https://github.com/Antynea/grub-btrfs/issues/92) for more info.

-Simple rollback using snapshots you made previously.
+This project includes its own solution.  
+Refer to the [documentation](https://github.com/Antynea/grub-btrfs/blob/master/initramfs/readme.md).

+##
+### What does grub-btrfs v4.xx do :
 * Automatically List snapshots existing on root partition (btrfs).
-
 * Automatically Detect if "/boot" is in separate partition.
+* Automatically Detect kernel, initramfs and intel/amd microcode in "/boot" directory on snapshots.
+* Automatically Create corresponding "menuentry" in `grub.cfg`
+* Automatically detect snapper and use snapper's snapshot description if available.
+* Automatically generate `grub.cfg` if you use the provided systemd service.

-* Automatically Detect kernel, initramfs and intel microcode in "/boot" directory on snapshots. (For custon name, see below.)
+##
+### Installation :
+#### Arch Linux

-* Automatically Create corresponding "menuentry" in grub.cfg , which ensures a very easy rollback.
+```
+pacman -S grub-btrfs
+```

+#### Manual

-#### How to use it:
+* Run `make install` or look into Makefile for instructions on where to put each file.

-Add this lines to /etc/default/grub:
+NOTE: Generate your Grub menu after installation for the changes to take effect.  
+On Arch Linux use `grub-mkconfig -o /boot/grub/grub.cfg`.

-* GRUB_BTRFS_SUBMENUNAME="ArchLinux Snapshots"
+##
+### Customization:

-	(Name menu appearing in grub.)
+You have the possibility to modify many parameters in `/etc/default/grub-btrfs/config`.  
+See [config file](https://github.com/Antynea/grub-btrfs/blob/master/config) for more information.

-* GRUB_BTRFS_PREFIXENTRY="Snapshot:"
+##
+### Automatically update grub
+If you would like Grub to automatically update when a snapshot is made or deleted:
+* Use `systemctl start/enable grub-btrfs.path`.
+* `grub-btrfs.path` automatically (re)generates `grub.cfg` when a modification appears in `/.snapshots` folder (by default).
+* If your snapshots aren't mounted in `/.snapshots`, you must modify the watch folder using `systemctl edit grub-btrfs.path`.  
+	* For example: Timeshift mount its snapshots in `/run/timeshift/backup/timeshift-btrfs/snapshots` folder.

-	(Add a name ahead your snapshots entries.)
-	
-* GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="true"
-	
-	(Show full path snapshot or only name)
-	
-* GRUB_BTRFS_TITLE_FORMAT="p/d/n"
-
- 	(Custom title, shows/hides p"prefix" d"date" n"name" in grub-menu, separator "/", custom order available)
-
-* GRUB_BTRFS_NKERNEL=("vmlinuz-linux")
-
-	(Use only if you have custom kernel name or auto-detect failed.)
-
-* GRUB_BTRFS_NINIT=("initramfs-linux.img" "initramfs-linux-fallback.img")
-
-	(Use only if you have custom initramfs name or auto-detect failed.)
-
-* GRUB_BTRFS_INTEL_UCODE=("intel-ucode.img")
-
-	(Use only if you have custom intel-ucode or auto-detect failed.)
-
-
-
-Generate grub.cfg (on Archlinux use grub-mkconfig -o /boot/grub/grub.cfg )
-
-grub-btrfs automatically generates snapshots entries.
-
-You will see it appear differents entries (e.g : Snapshot: [2014-02-12 11:24:37] my snapshot name overkill )
-
-
-#### TO DO
-
-* Display name of microcode in menuentry when available
-
-
-
-## discussion
-Pour les francophones : https://forums.archlinux.fr/viewtopic.php?f=18&t=17177
+		Use `systemctl edit grub-btrfs.path`.
+		Then wrote:
+		```
+		[Path]
+		PathModified=/run/timeshift/backup/timeshift-btrfs/snapshots
+		```
+		and finally save.
+	* You can view your change to `systemctl cat grub-btrfs.path`.
+	* To revert change use `systemctl revert grub-btrfs.path`.
+##
+### Special thanks for assistance and contributions
+* [maximbaz](https://github.com/maximbaz)
+* [All contributors](https://github.com/Antynea/grub-btrfs/graphs/contributors)
+##
--- a/111
+++ b/111
@@ -0,0 +1,111 @@
+#!/usr/bin/env bash
+
+# Disable grub-btrfs.
+# Default: "false"
+#GRUB_BTRFS_DISABLE="true"
+
+# Name appearing in the Grub menu.
+# Default: "Use distribution information from /etc/os-release."
+#GRUB_BTRFS_SUBMENUNAME="Arch Linux snapshots"
+
+# Add a name ahead your snapshots entries in the Grub menu.
+# Default: "Snapshot:"
+#GRUB_BTRFS_PREFIXENTRY="Snapshot:"
+
+# Show full path snapshot or only name in the Grub menu, weird reaction with snapper.
+# Default: "true"
+#GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="false"
+
+# Custom title.
+# shows/hides p"prefix" d"date" n"name" in the Grub menu, separator "/", custom order available.
+# Default: "p/d/n"
+#GRUB_BTRFS_TITLE_FORMAT="p/d/n"
+
+# Limit the number of snapshots populated in the GRUB menu.
+# Default: "50"
+#GRUB_BTRFS_LIMIT="50"
+
+# Sort the found subvolumes by "ogeneration" or "generation" or "path" or "rootid".
+# # See Sorting section to https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-subvolume#SUBCOMMAND
+# "-rootid" means list snapshot by new ones first.
+# Default: "-rootid"
+#GRUB_BTRFS_SUBVOLUME_SORT="+ogen,-gen,path,rootid"
+
+# Show snapshots found during run "grub-mkconfig"
+# Default: "true"
+#GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND="false"
+
+# Show Total of snapshots found during run "grub-mkconfig"
+# Default: "true"
+#GRUB_BTRFS_SHOW_TOTAL_SNAPSHOTS_FOUND="true"
+
+# By default, "grub-btrfs" automatically detects most existing kernels.
+# If you have one or more custom kernels, you can add them here.
+# Default: ("")
+#GRUB_BTRFS_NKERNEL=("kernel-custom" "vmlinux-custom")
+
+# By default, "grub-btrfs" automatically detects most existing initramfs.
+# If you have one or more custom initramfs, you can add them here.
+# Default: ("")
+#GRUB_BTRFS_NINIT=("initramfs-custom.img" "initrd-custom.img" "otherinit-custom.gz")
+
+# By default, "grub-btrfs" automatically detects most existing microcodes.
+# If you have one or more custom microcodes, you can add them here.
+# Default: ("")
+#GRUB_BTRFS_CUSTOM_MICROCODE=("custom-ucode.img" "custom-uc.img "custom_ucode.cpio")
+
+# Ignore specific path during run "grub-mkconfig".
+# Only exact paths are ignored.
+# e.g : if `specific path` = @, only `@` snapshot will be ignored.
+# Default: ("@")
+GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@")
+
+# Ignore prefix path during run "grub-mkconfig".
+# Any path starting with the specified string will be ignored.
+# e.g : if `prefix path` = @, all snapshots beginning with "@/..." will be ignored.
+# Default: ("var/lib/docker" "@var/lib/docker" "@/var/lib/docker")
+GRUB_BTRFS_IGNORE_PREFIX_PATH=("var/lib/docker" "@var/lib/docker" "@/var/lib/docker")
+
+# By default "grub-btrfs" automatically detects your boot partition,
+# either located at the system root or on a separate partition,
+# but cannot detect if it is in a subvolume.
+# Change to "true" if you have a boot partition in a different subvolume.
+# Default: "false"
+#GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION="true"
+
+# Location of the folder containing the "grub.cfg" file.
+# Use by grub-btrfs to save the file "grub-btrfs.cfg".
+# Might be grub2 on some systems.
+# For example, on Fedora with EFI : "/boot/efi/EFI/fedora"
+# Default: "/boot/grub"
+#GRUB_BTRFS_GRUB_DIRNAME="/boot/grub2"
+
+# Location of kernels/initramfs/microcode.
+# Use by "grub-btrfs" to detect the boot partition and the location of kernels/initrafms/microcodes.
+# Default: "/boot"
+#GRUB_BTRFS_BOOT_DIRNAME="/boot"
+
+# Name/path of grub-mkconfig, use by "grub-btrfs.service"
+# Might be 'grub2-mkconfig' on some systems
+# For example, on Fedora : "/sbin/grub2-mkconfig"
+# Default: /usr/bin/grub-mkconfig
+#GRUB_BTRFS_MKCONFIG=/usr/bin/grub2-mkconfig
+
+# Snapper
+# Snapper's config name to use
+# Default: "root"
+#GRUB_BTRFS_SNAPPER_CONFIG="root"
+
+# Password protection management for submenu,snapshots
+# Refer to the Grub documentation https://www.gnu.org/software/grub/manual/grub/grub.html#Authentication-and-authorisation
+# and this comment https://github.com/Antynea/grub-btrfs/issues/95#issuecomment-682295660
+#
+# Add authorized usernames separate by comma (foo,bar)
+# When Grub's password protection is enabled, the superuser is authorized by default, it isn't necessary to add it
+# Default: ""
+#GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS="foo,bar"
+#
+# Disable authentication support for submenu of Grub-btrfs only (--unrestricted)
+# doesn't work if GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS isn't empty
+# Default: "false"
+#GRUB_BTRFS_DISABLE_PROTECTION_SUBMENU="true"
--- a/grub-btrfs.path
+++ b/grub-btrfs.path
@@ -0,0 +1,8 @@
+[Unit]
+Description=Monitors for new snapshots
+
+[Path]
+PathModified=/.snapshots
+
+[Install]
+WantedBy=multi-user.target
--- a/grub-btrfs.service
+++ b/grub-btrfs.service
@@ -0,0 +1,11 @@
+[Unit]
+Description=Regenerate grub-btrfs.cfg
+
+[Service]
+Type=oneshot
+# Set the possible paths for `grub-mkconfig`
+Environment="PATH=/sbin:/bin:/usr/sbin:/usr/bin"
+# Load environment variables from the configuration
+EnvironmentFile=/etc/default/grub-btrfs/config
+# Regenerate just '/boot/grub/grub-btrfs.cfg' if it exists and is not empty, else regenerate the whole grub menu
+ExecStart=/bin/bash -c 'if [ -s "${GRUB_BTRFS_DIRNAME:-/boot/grub}/grub-btrfs.cfg" ]; then /etc/grub.d/41_snapshots-btrfs; else ${GRUB_BTRFS_MKCONFIG:-/usr/bin/grub-mkconfig} -o ${GRUB_BTRFS_DIRNAME:-/boot/grub}/grub.cfg; fi' 
--- a/Linux/overlay_snap_ro-hook
+++ b/Linux/overlay_snap_ro-hook
@@ -0,0 +1,15 @@
+#!/usr/bin/ash
+
+run_latehook() {
+	local root_mnt="/new_root"
+	local current_dev=$(resolve_device "$root"); # resolve devices for blkid
+	if [[ $(blkid "${current_dev}" -s TYPE -o value) = "btrfs" ]] && [[ $(btrfs property get ${root_mnt} ro) != "ro=false" ]]; then # run only on a read only snapshot
+		local lower_dir=$(mktemp -d -p /)
+		local ram_dir=$(mktemp -d -p /)
+		mount --move ${root_mnt} ${lower_dir} # move new_root to lower_dir
+		mount -t tmpfs cowspace ${ram_dir}  #meuh!!! space, you can't test !
+		mkdir -p ${ram_dir}/upper
+		mkdir -p ${ram_dir}/work
+		mount -t overlay -o lowerdir=${lower_dir},upperdir=${ram_dir}/upper,workdir=${ram_dir}/work rootfs ${root_mnt}
+	fi
+}
--- a/Linux/overlay_snap_ro-install
+++ b/Linux/overlay_snap_ro-install
@@ -0,0 +1,18 @@
+#!/bin/bash
+
+build() {
+    add_module btrfs
+    add_module overlay
+    add_binary btrfs
+    add_binary btrfsck
+    add_binary blkid
+    add_runscript
+}
+
+help() {
+    cat <<HELPEOF
+This hook uses overlayfs to boot on a read only snapshot.
+HELPEOF
+}
+
+# vim: set ft=sh ts=4 sw=4 et:
--- a/initramfs/readme.md
+++ b/initramfs/readme.md
@@ -0,0 +1,45 @@
+### Description :
+
+Booting on a snapshot in read-only mode can be tricky.  
+An elegant way is to boot this snapshot using overlayfs (included in the kernel ≥ 3.18).
+
+Using overlayfs, the booted snapshot will behave like a live-cd in non-persistent mode.  
+The snapshot will not be modified, the system will be able to boot correctly, because a writeable folder will be included in the ram.  
+(no more problems due to `/var` not open for writing)
+
+Any changes in this system thus started will be lost when the system is rebooted/shutdown.
+
+To do this, it is necessary to modify the initramfs.  
+This means that any snapshot that does not include this modified initramfs will not be able to benefit from it.  
+(except for separate boot partitions)
+#
+### Installation :
+#### Arch Linux
+1.
+`Pacman -S grub-btrfs`  
+Or if you use git  
+copy the `overlay_snap_ro-install` file to `/etc/initcpio/install/grub-btrfs-overlayfs`  
+copy the `overlay_snap_ro-hook` file to `/etc/initcpio/hooks/grub-btrfs-overlayfs`  
+You must rename the files. (I did it above)
+
+For example :  
+`overlay_snap_ro-install` to `grub-btrfs-overlayfs`  
+`overlay_snap_ro-hook` to `grub-btrfs-overlayfs`  
+Keep in mind that the files must have exactly the same name to ensure a match.
+
+2.
+Edit the file `/etc/mkinitcpio.conf`  
+Added hook `grub-btrfs-overlayfs` at the end of the line `HOOKS`.
+
+For example :  
+`HOOKS=(base udev autodetect modconf block filesystems keyboard fsck grub-btrfs-overlayfs)`  
+You notice that the name of the `hook` must match the name of the 2 installed files. (don't forget it)
+
+3.
+Re-generate your initramfs  
+`mkinitcpio -P` (option -P means, all preset present in `/etc/mkinitcpio.d`)
+
+#### Other distribution
+Refer to your distribution's documentation  
+or contribute to this project to add a paragraph.
+#
--- a/localisation/fr/grub-btrfs-git.mo
+++ b/localisation/fr/grub-btrfs-git.mo