Clean code

Clean indentation/leading/trailing space

41_snapshots-btrfs

@@ -1,76 +1,66 @@
 #! /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="Arch Linux snapshots" 												#
-#	(Name appearing in the Grub menu.)													#
-# * GRUB_BTRFS_PREFIXENTRY="Snapshot:"        		   											#
-#	(Add a name ahead your snapshots entries in the Grub menu.) 										#
-# * GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="true"													#
-#	(Show full path snapshot or only name in the Grub menu)											#
-# * GRUB_BTRFS_TITLE_FORMAT="p/d/n"														#
-#	(Custom title, shows/hides p"prefix" d"date" n"name" in the Grub menu, separator "/", custom order available)				#
-# * GRUB_BTRFS_LIMIT="100"															#
-#	(Limit the number of snapshots populated in the GRUB menu.)										#
-# * GRUB_BTRFS_SUBVOLUME_SORT="descending"													#
-#	(Sort the found subvolumes by newest first ("descending") or oldest first ("ascending").						#
-#	If "ascending" is chosen then the $GRUB_BTRFS_LIMIT oldest subvolumes will populate the menu.)						#
-# * GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND="true"													#
-#	(Show snapshots found during run "grub-mkconfig")											#
-# * GRUB_BTRFS_SHOW_TOTAL_SNAPSHOTS_FOUND="true"												#
-#	(Show Total of snapshots found during run "grub-mkconfig")										#
-# * 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.)		    							#
-# * GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker" "nosnapshot")										#
-#	(Ignore specific path during run "grub-mkconfig")											#
-# * GRUB_BTRFS_CREATE_ONLY_HARMONIZED_ENTRIES="false"												#
-#	(Create entries with matching version number instead of all possible combinations of kernel and initramfs)				#
-#																		#
-# - Generate grub.cfg (on Arch Linux 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:																	#
-#																		#
-#	* Snapper support ....															#
-#																		#
-#################################################################################################################################################
+#########################################################################################################################################################################
+# 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
+#   (If you choose to do it, /var/log must be on a separate subvolume.Otherwise, make sure your snapshots are writeable.)
+#
+# 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:
+# - Mount your subvolume which contains snapshots to /.snapshots
+# - Use systemctl start/enable grub-btrfs.path
+#  grub-btrfs.path will automatically (re)generate grub.cfg when a modification appear in /.snapshots
+#
+# 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 ###
-######################################
+###################################################
+### Variables in /etc/default/grub-btrfs/config ###
+###################################################
+## Disable Grub-btrfs (default=active)
+grub_btrfs_disable=${GRUB_BTRFS_DISABLE:-"false"}
+[[ "${grub_btrfs_disable}" == "true" ]] && exit 0
 ## Submenu name
-submenuname=${GRUB_BTRFS_SUBMENUNAME:-"Arch Linux snapshots"}
+distro=$(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
@@ -82,39 +72,53 @@ nkernel=("${GRUB_BTRFS_NKERNEL[@]}")
 ## Initramfs name(s)
 ninit=("${GRUB_BTRFS_NINIT[@]}")
 ## Microcode(s) name(s)
-microcode=("${GRUB_BTRFS_INTEL_UCODE[@]}")
-## Limit to show in the Grub menu
-limit_snap_show="${GRUB_BTRFS_LIMIT:-100}"
+microcode=("${GRUB_BTRFS_CUSTOM_MICROCODE[@]}")
+## Limit snapshots to show in the Grub menu
+limit_snap_show="${GRUB_BTRFS_LIMIT:-50}"
 ## How to sort snapshots list
-snap_list_sort=${GRUB_BTRFS_SUBVOLUME_SORT:-"descending"}
-case "${snap_list_sort}" in
-    ascending)          btrfssubvolsort=("--sort=+rootid");;
-    *)                  btrfssubvolsort=("--sort=-rootid")
-esac
+btrfssubvolsort=(--sort="${GRUB_BTRFS_SUBVOLUME_SORT:-"-rootid"}")
 ## Show snapshots found during run "grub-mkconfig"
 show_snap_found=${GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND:-"true"}
 ## Show Total of snapshots found during run "grub-mkconfig"
 show_total_snap_found=${GRUB_BTRFS_SHOW_TOTAL_SNAPSHOTS_FOUND:-"true"}
 ## Ignore specific path during run "grub-mkconfig"
 ignore_specific_path=("${GRUB_BTRFS_IGNORE_SPECIFIC_PATH[@]}")
-## create only entries with harmonized version numbers
-harmonized_entries=${GRUB_BTRFS_CREATE_ONLY_HARMONIZED_ENTRIES:-"false"}
-
+## Snapper's config name
+snapper_config=${GRUB_BTRFS_SNAPPER_CONFIG:-"root"}
+## Override boot partition detection
+override_boot_partition_detection=${GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION:-"false"}
+## Customize GRUB directory
+grub_directory=${GRUB_BTRFS_DIRNAME:-"grub"}
+## Password protection management for submenu
+# Protection support for submenu (--unrestricted)
+unrestricted_access_submenu=${GRUB_BTRFS_DISABLE_PROTECTION_SUBMENU:-"false"}
+case "${unrestricted_access_submenu}" in
+	true)	unrestricted_access_submenu="--unrestricted ";;
+	*)		unrestricted_access_submenu=""
+esac
+# Authorized users (--users foo,bar)
+protection_authorized_users=${GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS}
+if [ ! -z "${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)
+## Probe info "Boot partition"
+# Boot device
+boot_device=$(${grub_probe} --target=device /boot)
+# 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 ${boot_device} --target="fs_uuid" 2>/dev/null)
+# Type filesystem of boot partition
+boot_fs=$(${grub_probe} --target="fs" /boot 2>/dev/null)
+## Probe info "Root partition"
+# Root device
+root_device=$(${grub_probe} --target=device /)
+# UUID of the root partition
+root_uuid=$(${grub_probe} --device ${root_device} --target="fs_uuid" 2>/dev/null)
 ## Parameters passed to the kernel
 kernel_parameters="$GRUB_CMDLINE_LINUX $GRUB_CMDLINE_LINUX_DEFAULT"
 ## Mount point location
@@ -123,123 +127,110 @@ gbgmp=$(mktemp -d)
 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
+}
+
+test_btrfs()
+{
+	set +e
+	type btrfs >/dev/null 2>&1
+	if [[ $? -ne 0 ]]; then
+		print_error "This script only supports snapshots of the btrfs filesystem, make sure you have btrfs-progs on your system."
+	fi
+	set -e
+}
+
 ##############
 ### Script ###
 ##############
 
-### BEGIN auto detect ###
+
+## Create entry
+entry()	{
+echo "$@" >> "/boot/$grub_directory/grub-btrfs.cfg"
+# local arg="$@"
+# echo "${arg}" >> "/boot/$grub_directory/grub-btrfs.cfg"
+# cat << EOF >> "/boot/$grub_directory/grub-btrfs.cfg"
+# ${arg}
+# EOF
+}
 
 ## menu entries
-snapshots_entry()
+make_menu_entries()
 {
 ## \" required for snap,kernels,init,microcode with space in their name
-	echo "	submenu '$title_menu' {
-		submenu '---> $title_menu <---' { echo }
-	"
+	entry "submenu '$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 [ -f "$(boot_dir)"/"${u}" ] ; then
-				echo "\
-		menuentry '"${k}" & "${i}" & "${u}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid'{"
-			else 
-				echo "\
-		menuentry '"${k}" & "${i}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid'{"
-			fi
-			echo "\
-			$(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}/"${u}"\" \"${boot_dir_real_path}/"${i}"\""
-			else
-				echo "\
-			echo 'Loading Initramfs: "${i}" ...'
-			initrd \"${boot_dir_real_path}/"${i}"\""
-			fi
-		echo "		}"
+				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
-	echo "	}"
-}
-
-harmonized_snapshots_entry()
-{
-## \" 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
-		version=${k#vmlinuz-}
-		i=""
-		if [ -f "$(boot_dir)"/initramfs-"${version}".img ]; then
-			i=initramfs-${version}.img
-		else
-			if [ -f "$(boot_dir)"/initrd.img-"${version}" ]; then
-				i=initrd.img-${version}
-			fi
-		fi
-		for u in "${name_microcode[@]}"; do
-			if [ -f "$(boot_dir)"/"${u}" ] ; then
-				echo "\
-		menuentry '"${k}" & "${i}" & "${u}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid'{"
-			else 
-				echo "\
-		menuentry '"${k}" & "${i}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid'{"
-			fi
-			echo "\
-			$(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)"/"${i}" ] ; then
-				if [ -f "$(boot_dir)"/"${u}" ] ; then
-					echo "\
-			echo 'Loading Microcode & Initramfs: "${u}" "${i}" ...'
-			initrd \"${boot_dir_real_path}/"${u}"\" \"${boot_dir_real_path}/"${i}"\""
-				else
-					echo "\
-			echo 'Loading Initramfs: "${i}" ...'
-			initrd \"${boot_dir_real_path}/"${i}"\""
-				fi
-			fi
-			echo "		}"
-		done
-	done
-	echo "	}"
+	entry  "}"
 }
 
 ## Trim a string from leading and trailing whitespaces
@@ -255,12 +246,17 @@ snapshot_list()
 {
 	# Query info from snapper if it is installed
 	type snapper >/dev/null 2>&1
-	if [[ $? -eq 0 ]]; then
-		local snapper_ids=($(snapper -t 0 list -a | tail -n +3 | cut -d'|' -f 2))
-		local snapper_types=($(snapper -t 0 list -a | tail -n +3 | cut -d'|' -f 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 -t 0 list -a | tail -n +3 | cut -d'|' -f 7))
+			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=$'\n'
@@ -273,10 +269,22 @@ snapshot_list()
 		IFS=$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 "${ignore_specific_path}" ] ; then
+			[[ "${snap_path_name}" == "@" ]] && continue 2;
+			for isp in ${ignore_specific_path[@]} ; do
+				[[ "${snap_path_name}" == "${isp}" || "${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")
 
@@ -306,6 +314,10 @@ snapshot_list()
 		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]}")
@@ -322,15 +334,19 @@ snapshot_list()
 ## Detect kernels in "/boot"
 detect_kernel()
 {
-	## Arch original kernel (auto-detect)
-	for akernel in "$(boot_dir)"/vmlinuz-* ; do 
-		list_kernel+=("$akernel")
+	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
+	# Custom name kernel in GRUB_BTRFS_NKERNEL
 	if [ ! -z "${nkernel}" ] ; then
-		for ckernel in "${nkernel[@]}" ; do
-			[[ ! -f /"$(boot_dir)"/"${ckernel}" ]] && continue;
+		for ckernel in "${boot_dir}/${nkernel[@]}" ; do
+			[[ ! -f "${ckernel}" ]] && continue;
 			list_kernel+=("$ckernel")
 		done
 	fi
@@ -339,15 +355,21 @@ detect_kernel()
 ## Detect initramfs in "/boot"
 detect_initramfs()
 {
-	## Arch original initramfs (auto-detect)
-	for ainitramfs in "$(boot_dir)"/initramfs-* ; do 
-		list_initramfs+=("$ainitramfs")
+	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+=("$oinitramfs")
 	done
-	
-	## Custom name initramfs in GRUB_BTRFS_NINIT
+
+	# Custom name initramfs in GRUB_BTRFS_NINIT
 	if [ ! -z "$ninit" ] ; then
-		for cinitramfs in "${ninit[@]}" ; do
-			[[ ! -f /"$(boot_dir)"/"${cinitramfs}" ]] && continue;
+		for cinitramfs in "${boot_dir}/${ninit[@]}" ; do
+			[[ ! -f "${cinitramfs}" ]] && continue;
 			list_initramfs+=("$cinitramfs")
 		done
 	fi
@@ -356,18 +378,27 @@ detect_initramfs()
 ## Detect microcode in "/boot"
 detect_microcode()
 {
-	## Arch original intel microcode
-	for aucode in "$(boot_dir)"/intel-ucode.img ; do
-		list_ucode+=("$aucode")
+	list_ucode=()
+	# Original intel/amd microcode (auto-detect)
+	# See "https://www.gnu.org/software/grub/manual/grub/html_node/Simple-configuration.html"
+	for oiucode in  "${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
+	# Custom name microcode in GRUB_BTRFS_INTEL_UCODE
 	if [ ! -z "$microcode" ] ; then
-		for cucode in "${microcode[@]}" ; do
-			[[ ! -f /"$(boot_dir)"/"${cucode}" ]] && continue
+		for cucode in "${boot_dir}/${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
@@ -383,103 +414,161 @@ path_snapshot()
 title_format()
 {
 	case "${title_format}" in
-		p/d/n) 	title_menu="${prefixentry} ${snap_date_time} ${name_snapshot}";;
 		p/n/d) 	title_menu="${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}";;
-		*)	gettext_printf $"# Warning: GRUB_BTRFS_TITLE_FORMAT=${title_format}, syntax error \n" >&2
+		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()
 {
+	# Initialize menu entries
 	IFS=$'\n'
-	count_limit_snap=0
 	for item in $(snapshot_list); do
-		### fix: limit_snap_show=0
+		# fix: limit_snap_show=0
 		[[ ${limit_snap_show} -le 0 ]] && break;
 		IFS=$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")"
-
-		### ignore specific path during run "grub-mkconfig"
-		if [ ! -z "${ignore_specific_path}" ] ; then
-			for isp in ${ignore_specific_path[@]} ; do
-				[[ "${gbgmp}"/"${snap_dir_name}" == "${gbgmp}"/"${isp}"/* ]] && continue 2;
-			done
-		fi
-		### detect if /boot directory exists
-		[[ ! -d "$gbgmp/$snap_dir_name/boot" ]] && continue;
-		### show snapshot found during run "grub-mkconfig"
 		snap_date_time="$(echo "$item" | cut -d' ' -f1-2)"
 		snap_date_time="$(trim "$snap_date_time")"
-		if [[ "${show_snap_found}" = "true" ]]; then
-		gettext_printf $"# Found snapshot: %s\n" "$item" >&2 ;
-		fi
-		### Kernel (auto-detect + custom kernel)
-		unset list_kernel
+		
+		boot_dir="$gbgmp/$snap_dir_name/boot"
+		# Kernel (Original + custom kernel)
 		detect_kernel
+		if [ -z "${list_kernel}" ]; then continue; fi
 		name_kernel=("${list_kernel[@]##*"/"}")
-		# echo "kernel = ${name_kernel[*]}"
-		if [[ "${harmonized_entries}" != "true" ]]; then
-			### Initramfs (autodetect + custom initramfs)
-			unset list_initramfs
-			detect_initramfs
-			name_initramfs=("${list_initramfs[@]##*"/"}")
-			# echo "initramfs = ${name_initramfs[*]}"
-		fi
-		### microcode (auto-detect + custom microcode)
-		unset list_ucode
+		# Initramfs (Original + custom initramfs)
+		detect_initramfs
+		if [ -z "${list_initramfs}" ]; then continue; fi
+		name_initramfs=("${list_initramfs[@]##*"/"}")
+		# microcode (auto-detect + custom microcode)
 		detect_microcode
 		name_microcode=("${list_ucode[@]##*"/"}")
-		# echo "ucode = ${name_microcode[*]}"
-		### real path to boot
-		boot_dir_real_path="$(make_system_path_relative_to_its_root "$(boot_dir)")"
-		### Create menu entries
-		## name snapshot
-		path_snapshot
-		## title menu custom
-		title_format
-		# echo "${title_menu}"
-		if [[ "${harmonized_entries}" = "false" ]]; then
-			snapshots_entry
-		else
-			harmonized_snapshots_entry
+		# show snapshot found during run "grub-mkconfig"
+		if [[ "${show_snap_found}" = "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 $limit_snap_show ]] && break;
+		count_limit_snap=$((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
+}
+boot_separate()
+{
+	boot_dir="/boot"
+	# convert /boot directory to root of GRUB (e.g /boot become /)
+	boot_dir_root_grub="$(make_system_path_relative_to_its_root "${boot_dir}")"
+
+	# 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
+		# fix: limit_snap_show=0
+		[[ ${limit_snap_show} -le 0 ]] && break;
+		IFS=$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 [[ "${show_snap_found}" = "true" ]]; then
+		printf "Found snapshot: %s\n" "$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
 }
-### END auto detect ###
 
 ### Start ###
-	gettext_printf "###### - Grub-btrfs: Auto-detect Start - ######\n" >&2 ;
-	### create mount point and mounts
-	[[ ! -d $gbgmp ]] && mkdir -p $gbgmp
-	mount -o subvolid=5 /dev/disk/by-uuid/$root_uuid $gbgmp/
-	### Create a menu in grub
-	echo "submenu '${submenuname}' {"
-	list_kernels_initramfs ;
-	## show total found snapshots
-	if [[ "${show_total_snap_found}" = "true" ]]; then
-	gettext_printf "# Found ${count_limit_snap} snapshot(s)\n" >&2 ;
+printf "Detecting snapshots ...\n" >&2 ;
+# if btrfs prog isn't installed, exit
+test_btrfs
+# Delete existing config
+#rm -f --preserve-root "/boot/$grub_directory/grub-btrfs.cfg"
+> "/boot/$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 $gbgmp/
+# Count menuentries
+count_warning_menuentries=0
+# Count snapshots
+count_limit_snap=0
+# detect uuid requirement
+check_uuid_required
+# Detects if /boot is a separate partition
+if [[ "$override_boot_partition_detection" == "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
-	## if no snapshot found, show a warning 
-	if [[ "${count_limit_snap}" = "0" ]]; then
-		echo " submenu '---> "No snapshot found : Press ESC to return previous menu" <---' { echo } ";
-		gettext_printf "# No snapshot found \n# make sure you have at least one snapshot \n# or please file a bug report at \"https://github.com/Antynea/grub-btrfs\"\n" >&2 ;
-	fi
-	echo "}"
-	## unmount mount point
-	umount $gbgmp
-	gettext_printf "###### - Grub-btrfs: Auto-detect End   - ######\n" >&2 ;
+fi
+# 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 = $count_warning_menuentries \n" >&2 ;
+# Show total found snapshots
+if [[ "${show_total_snap_found}" = "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 ###

Makefile

@@ -0,0 +1,23 @@
+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
+
+uninstall:
+	rm -f "$(DESTDIR)/etc/grub.d/41_snapshots-btrfs"
+	rm -f "$(DESTDIR)/etc/default/grub-btrfs/config"
+	rmdir --ignore-fail-on-non-empty "$(DESTDIR)/etc/default/grub-btrfs"
+	rm -f "$(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"

README.md

@@ -1,99 +1,169 @@
-[![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)
 
-This is a version 2.xx of grub-btrfs
+## grub-btrfs
 
-#### Description
+This is a version 4.xx of grub-btrfs
+##### BTC donation address: `1Lbvz244WA8xbpHek9W2Y12cakM6rDe5Rt`
+##
+### Description
+Improves Grub by adding "btrfs snapshots" to the Grub menu.
 
-grub-btrfs, Include btrfs snapshots at boot options. (grub menu)
+You can start your system on a "snapshot" from the Grub menu.
 
-#### What does grub-btrfs v2.xx do :
+Supports manual snapshots, snapper, timeshift ...
 
-Simple rollback using snapshots you made previously.
+##### Warning: booting on read-only snapshots can be tricky
 
+If you choose to do it, `/var/log` 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.
+
+### 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 microcode in "/boot" directory on snapshots. (For custom name, see below.)
-
-* Automatically Create corresponding "menuentry" in grub.cfg , which ensures a very easy rollback.
-
+* 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.
+##
+### Installation :
+#### Arch Linux
 
+```
+pacman -S grub-btrfs
+```
 
-#### How to use it:
+### Manual
 
-Add this lines to /etc/default/grub:
+* Run `make install` or look into Makefile for instructions on where to put each file.
+
+NOTE: Generate your Grub menu after installation for the changes to take effect.
+
+On Arch Linux use `grub-mkconfig -o /boot/grub/grub.cfg`.
+
+##
+### Customization:
+
+You have the possibility to modify many parameters in `/etc/default/grub-btrfs/config`.
 
 * GRUB_BTRFS_SUBMENUNAME="Arch Linux Snapshots"
 
-	(Name menu appearing in grub.)
+	Name appearing in the Grub menu. Use distribution information from /etc/os-release by default.
 
 * GRUB_BTRFS_PREFIXENTRY="Snapshot:"
 
-	(Add a name ahead your snapshots entries.)
+	Add a name ahead your snapshots entries in the Grub menu.
 	
 * GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="true"
 	
-	(Show full path snapshot or only name, weird reaction with snapper)
+	Show full path snapshot or only name in the Grub menu, weird reaction with snapper.
 	
 * GRUB_BTRFS_TITLE_FORMAT="p/d/n"
 
- 	(Custom title, shows/hides p"prefix" d"date" n"name" in grub-menu, separator "/", custom order available)
+ 	Custom title, shows/hides p"prefix" d"date" n"name" in the Grub menu, separator "/", custom order available.
 
-* GRUB_BTRFS_NKERNEL=("vmlinuz-linux")
+* GRUB_BTRFS_LIMIT="50"
 
-	(Use only if you have a custom kernel name or auto-detect failed.)
+	Limit the number of snapshots populated in the GRUB menu.
 
-* GRUB_BTRFS_NINIT=("initramfs-linux.img" "initramfs-linux-fallback.img")
+* GRUB_BTRFS_SUBVOLUME_SORT="+ogen,-gen,path,rootid"
 
-	(Use only if you have a 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.)
-
-* GRUB_BTRFS_LIMIT="100"
-
-	(Limit the number of snapshots populated in the GRUB menu.)
-
-* GRUB_BTRFS_SUBVOLUME_SORT="descending"
-
-	(Sort the found subvolumes by newest first ("descending") or oldest first ("ascending"). 
-	If "ascending" is chosen then the $GRUB_BTRFS_LIMIT oldest
-	subvolumes will populate the menu.)
+	Sort the found subvolumes by "ogeneration" or "generation" or "path" or "rootid".
+	
+	Default: "-rootid" means list snapshot by new ones first
+	
+	See [Sorting section](https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-subvolume#SUBCOMMAND)
 
 * GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND="true"
 	
-	(Show snapshots found during run "grub-mkconfig") 
+	Show snapshots found during run "grub-mkconfig".
 	
 * GRUB_BTRFS_SHOW_TOTAL_SNAPSHOTS_FOUND="true"
 	
-	(Show Total number of snapshots found during run "grub-mkconfig")
+	Show Total number of snapshots found during run "grub-mkconfig".
 
-* GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker" "nosnapshot")
+* GRUB_BTRFS_NKERNEL=("kernel-custom")
 
-	(Ignore specific path during run "grub-mkconfig")
+	Use it only if you have a custom kernel name
 
-* GRUB_BTRFS_CREATE_ONLY_HARMONIZED_ENTRIES="false"
+* GRUB_BTRFS_NINIT=("initramfs-custom.img" "initrd.img-custom")
 
-	(Create entries with matching version number instead of all possible combinations of kernel and initramfs, very useful with debian-like distributions)
+	Use it only if you have a custom initramfs name.
+
+* GRUB_BTRFS_CUSTOM_MICROCODE=("intel-ucode.img")
+
+	Use it only if you have custom microcode.
+
+* GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker")
+
+	Ignore specific path during run "grub-mkconfig".
+	
+	For example: 
+	
+	If path is a directory `# Found Snapshot: 2016-03-31 10:24:41` **var/lib/docker/btrfs/subvolumes/...**
+	
+	use : `GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker")`
+	
+	If path is a subvolume : `# Found Snapshot: 2016-03-31 10:24:41` **@var/lib/docker/btrfs/subvolumes/...**
+	
+	use : `GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@var/lib/docker")`
+	
+	You can combine them
+	
+	use : `GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@var/lib/docker" "var/lib/docker")`
 
 
+* GRUB_BTRFS_SNAPPER_CONFIG="root"													
 
-Generate grub.cfg (on Arch linux use grub-mkconfig -o /boot/grub/grub.cfg )
+	Snapper's config name to use.
 
-grub-btrfs automatically generates snapshots entries.
+* GRUB_BTRFS_DISABLE="false"
 
-You will see it appear differents entries (e.g : Snapshot: 2018-01-03 15:08:41  @test1 )
+	Disable grub-btrfs.
 
+* GRUB_BTRFS_DIRNAME="grub"
 
-#### TO DO
+	Name of the grub folder in `/boot/`, might be grub2 on some distributions.
 
-* don't hesitate to ask for improvements
+* GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION="false"
 
+	Change to "true" if you have a boot partition in a different subvolume.
 
-## discussion
-Pour les francophones : https://forums.archlinux.fr/viewtopic.php?f=18&t=17177
+* GRUB_BTRFS_MKCONFIG=grub-mkconfig
+
+	Name or path of the 'grub-mkconfig' executable; might be 'grub2-mkconfig' on some distributions.
+	
+- Password protection management for submenu (refer to the [Grub documentation](https://www.gnu.org/software/grub/manual/grub/grub.html#Authentication-and-authorisation))
+
+	- GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS=""
+
+		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
+		
+	- GRUB_BTRFS_DISABLE_PROTECTION_SUBMENU="false"
+
+		Disable authentication support for submenu of Grub-btrfs only (--unrestricted)
+	
+		doesn't work if `GRUB_BTRFS_PROTECTION_AUTHORIZED_USERS` isn't empty
+
+##
+### Automatically update grub
+If you would like Grub to automatically update when a snapshot is made or deleted:
+* Mount your subvolume which contains snapshots to `/.snapshots`
+* Use `systemctl start/enable grub-btrfs.path`
+* `grub-btrfs.path` automatically (re)generates `grub.cfg` when a modification appears in `/.snapshots`
+##
+### Special thanks for assistance and contributions
+* [maximbaz](https://github.com/maximbaz)
+* [crossroads1112](https://github.com/crossroads1112)
+* [penetal](https://github.com/penetal)
+* [wesbarnett](https://github.com/wesbarnett)
+* [Psykar](https://github.com/Psykar)
+* [anyc](https://github.com/anyc)
+* [daftaupe](https://github.com/daftaupe)
+* [N-Parsons](https://github.com/N-Parsons)
+##

config

@@ -0,0 +1,88 @@
+#!/usr/bin/env bash
+
+# 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
+# Default: "true"
+#GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="true"
+
+# 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"
+# Default: "-rootid"
+# See Sorting section to https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-subvolume#SUBCOMMAND
+#GRUB_BTRFS_SUBVOLUME_SORT="+ogen,-gen,path,rootid"
+
+# Show snapshots found during run "grub-mkconfig"
+# Default: "true"
+#GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND="true"
+
+# Show Total of snapshots found during run "grub-mkconfig"
+# Default: "true"
+#GRUB_BTRFS_SHOW_TOTAL_SNAPSHOTS_FOUND="true"
+
+# Use only if you have custom kernel name
+# Default:
+#GRUB_BTRFS_NKERNEL=("vmlinuz-linux")
+
+# Use only if you have custom initramfs name
+# Default:
+#GRUB_BTRFS_NINIT=("initramfs-linux.img" "initramfs-linux-fallback.img")
+
+# Use only if you have custom microcode
+# Default:
+#GRUB_BTRFS_CUSTOM_MICROCODE=("intel-ucode.img")
+
+# Ignore specific path during run "grub-mkconfig".
+# If path is a directory, # Found Snapshot: 2016-03-31 10:24:41 var/lib/docker/btrfs/subvolumes/...
+# use : GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker");
+# If path is a subvolume, # Found Snapshot: 2016-03-31 10:24:41 @var/lib/docker/btrfs/subvolumes/...
+# use : GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@var/lib/docker");
+# You can combine them
+# use : GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@var/lib/docker" "var/lib/docker")
+# Default: 
+GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker" "@var/lib/docker")
+
+# Snapper's config name to use
+# Default: "root"
+#GRUB_BTRFS_SNAPPER_CONFIG="root"
+
+# Disable Grub-btrfs
+# Default: "false"
+#GRUB_BTRFS_DISABLE="false"
+
+# Change to "true" if you have a boot partition in a different subvolume
+# Default: "false"
+#GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION="false"
+
+# Might be grub2 on some systems ex. /boot/grub2/...
+# Default: "grub"
+#GRUB_BTRFS_DIRNAME="grub"
+
+# Might be 'grub2-mkconfig' on some systems
+# Default: /usr/bin/grub-mkconfig
+#GRUB_BTRFS_MKCONFIG=/usr/bin/grub2-mkconfig
+
+## Password protection management for submenu,snapshots
+# 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=""
+#
+# 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="false"

grub-btrfs.path

@@ -0,0 +1,8 @@
+[Unit]
+Description=Monitors for new snapshots
+
+[Path]
+PathModified=/.snapshots
+
+[Install]
+WantedBy=multi-user.target

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 "/boot/${GRUB_BTRFS_DIRNAME:-grub}/grub-btrfs.cfg" ]; then /etc/grub.d/41_snapshots-btrfs; else ${GRUB_BTRFS_MKCONFIG:-/usr/bin/grub-mkconfig} -o /boot/${GRUB_BTRFS_DIRNAME:-grub}/grub.cfg; fi'