Adds a new config variable "GRUB_BTRFS_ROOTFLAGS" (#133)

Script:

Improves the rootflags option in the kernel command line:
- Remove "rw" flag.
- Parse fstab mountoptions and add them to rootflags:
Adds functionality to read in  snapshot specific mount flags
from the respective fstab and uses them in combination with the new 
config option, while the latter is prioritized.
Both places can, but don't need to define mount flags. If either of them
doesn't, it will simply not be taken into account.

Config file:

Adds a new config variable "GRUB_BTRFS_ROOTFLAGS":
- The new variable is used to include user-defined rootflags in the 
kernel command line of generated snapshot bootmenu entries.
See config file for more infos.

41_snapshots-btrfs

@@ -1,7 +1,6 @@
 #! /usr/bin/env bash
 #
 #
-#########################################################################################################################################################################
 # Written by: Antynea
 # BTC donation address: 1Lbvz244WA8xbpHek9W2Y12cakM6rDe5Rt
 # Github: https://github.com/Antynea/grub-btrfs
@@ -10,7 +9,8 @@
 #   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 : it isn't recommended to start on read-only snapshot
+#   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).
@@ -29,15 +29,15 @@
 #
 # 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
-# - Use systemctl start/enable grub-btrfs.path
+#  - grub-btrfs.path automatically (re)generates grub.cfg when a modification appears in /.snapshots folder (by default).
-#  grub-btrfs.path will automatically (re)generate grub.cfg when a modification appear in /.snapshots
+#  - 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
 
@@ -51,63 +51,48 @@ grub_btrfs_config="${sysconfdir}/default/grub-btrfs/config"
 . "$datarootdir/grub/grub-mkconfig_lib"
 . "${sysconfdir}/default/grub"
 
-###################################################
+### Variables in /etc/default/grub-btrfs/config
-### Variables in /etc/default/grub-btrfs/config ###
-###################################################
 ## Disable Grub-btrfs (default=active)
-grub_btrfs_disable=${GRUB_BTRFS_DISABLE:-"false"}
+[[ "${GRUB_BTRFS_DISABLE:-"false"}" == "true" ]] && exit 0
-[[ "${grub_btrfs_disable}" == "true" ]] && exit 0
 ## Submenu name
-submenuname=${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
-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
-snap_list_sort=${GRUB_BTRFS_SUBVOLUME_SORT:-"descending"}
+btrfssubvolsort=(--sort="${GRUB_BTRFS_SUBVOLUME_SORT:-"-rootid"}")
-case "${snap_list_sort}" in
-    ascending)          btrfssubvolsort=("--sort=+rootid");;
-    *)                  btrfssubvolsort=("--sort=-rootid")
-esac
-## Show snapshots found during run "grub-mkconfig"
-show_snap_found=${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[@]}")
 ## Snapper's config name
 snapper_config=${GRUB_BTRFS_SNAPPER_CONFIG:-"root"}
-## Override boot partition detection
+## Customize GRUB directory, where "grub.cfg" file is saved
-override_boot_partition_detection=${GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION:-"false"}
+grub_directory=${GRUB_BTRFS_GRUB_DIRNAME:-"/boot/grub"}
-## Customize GRUB directory
+## Customize BOOT directory, where kernels/initrams/microcode is saved.
-grub_directory=${GRUB_BTRFS_DIRNAME:-"grub"}
+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
-### variables script ###
-########################
-## Internationalization (default : english)
-export TEXTDOMAIN=grub-btrfs-git
-export TEXTDOMAINDIR="/usr/share/locale"
 ## Probe info "Boot partition"
 # Boot device
-boot_device=$(${grub_probe} --target=device /boot)
+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 ${boot_device} --target="fs_uuid" 2>/dev/null)
 # Type filesystem of boot partition
-boot_fs=$(${grub_probe} --target="fs" /boot 2>/dev/null)
+boot_fs=$(${grub_probe} --device ${boot_device} --target="fs" 2>/dev/null)
 ## Probe info "Root partition"
+# Type filesystem of root partition
+root_fs=$(${grub_probe} --target="fs" / 2>/dev/null)
 # Root device
 root_device=$(${grub_probe} --target=device /)
 # UUID of the root partition
@@ -125,391 +110,405 @@ check_uuid_required() {
 if [ "x${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=${root_device}
+    LINUX_ROOT_DEVICE=${root_device}
 else
-  LINUX_ROOT_DEVICE=UUID=${root_uuid}
+    LINUX_ROOT_DEVICE=UUID=${root_uuid}
 fi
 }
+## Detect rootflags
+detect_rootflags()
+{
+    local fstabflags=$(grep -oE '^\s*[^#][[:graph:]]+\s+/\s+btrfs\s+[[:graph:]]+' "${gbgmp}/${snap_dir_name}/etc/fstab" \
+                        | sed -E 's/^.*[[:space:]]([[:graph:]]+)$/\1/;s/,?subvol(id)?=[^,$]+//g;s/^,//')
+    rootflags="rootflags=${fstabflags:+$fstabflags,}${GRUB_BTRFS_ROOTFLAGS:+$GRUB_BTRFS_ROOTFLAGS,}"
+}
 
-
+### Error Handling
-######################
-### Error Handling ###
-######################
 print_error()
 {
-	local arg="$@"
+    local arg="$@"
-	local nothing_to_do="If you think an error has occurred , please file a bug report at \" https://github.com/Antynea/grub-btrfs \"\n# Nothing to do. Abort.\n###### - Grub-btrfs: Snapshot detection ended   - ######\n"
+    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# ${nothing_to_do}" >&2 ;
+    printf "${arg}\n${nothing_to_do}" >&2 ;
-	exit 0
+    exit 0
 }
 
 test_btrfs()
 {
-	set +e
+    [[ "$root_fs" != "btrfs" ]] && print_error "Root partition isn't a btrfs filesystem.\nThis script only supports snapshots of the btrfs filesystem."
-	type btrfs >/dev/null 2>&1
+    set +e
-	if [[ $? -ne 0 ]]; then
+    type btrfs >/dev/null 2>&1
-		print_error "This script only supports snapshots of the btrfs filesystem, make sure you have btrfs-progs on your system."
+    if [[ $? -ne 0 ]]; then
-	fi
+        print_error "Unable to retrieve info from btrfs filesystem, make sure you have btrfs-progs on your system."
-	set -e
+    fi
+    set -e
 }
-##############
-### Script ###
-##############
-
 
+### Script
 ## Create entry
-entry()	{
+entry()
-echo "$@" >> "/boot/$grub_directory/grub-btrfs.cfg"
+{
-# local arg="$@"
+echo "$@" >> "$grub_directory/grub-btrfs.cfg"
-# echo "${arg}" >> "/boot/$grub_directory/grub-btrfs.cfg"
-# cat << EOF >> "/boot/$grub_directory/grub-btrfs.cfg"
-# ${arg}
-# EOF
 }
 
 ## menu entries
 make_menu_entries()
 {
 ## \" required for snap,kernels,init,microcode with space in their name
-	entry "submenu '$title_menu' {
+    entry "submenu '$title_menu' {
-	submenu '---> $title_menu <---' { echo }"
+    submenu '---> $title_menu <---' { echo }"
-	for k in "${name_kernel[@]}"; do
+    for k in "${name_kernel[@]}"; do
-		[[ ! -f "${boot_dir}"/"${k}" ]] && continue;
+        [[ ! -f "${boot_dir}"/"${k}" ]] && continue;
-		kversion=${k#*"-"}
+        kversion=${k#*"-"}
-		for i in "${name_initramfs[@]}"; do
+        for i in "${name_initramfs[@]}"; do
-			prefix_i=${i%%"-"*}
+            prefix_i=${i%%"-"*}
-			suffix_i=${i#*"-"}
+            suffix_i=${i#*"-"}
-         	alt_suffix_i=${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="${i}";
-			else 	continue ;
+            else continue ;
-			fi
+            fi
-			for u in "${name_microcode[@]}"; do
+            for u in "${name_microcode[@]}"; do
-				if [[ -f "${boot_dir}"/"${u}" && "${i}" != "${prefix_i}-${kversion}-${alt_suffix_i}" ]] ; then
+                if [[ "${name_microcode}" != "x" ]] ; then
-				entry "
+                    entry "
-	menuentry '"${k}" & "${i}" & "${u}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid'{"
+    menuentry '"${k}" & "${i}" & "${u}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid' {"
-				else
+                else
-				entry "
+                    entry "
-	menuentry '"${k}" & "${i}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid'{"
+    menuentry '"${k}" & "${i}"' ${CLASS} "\$menuentry_id_option" 'gnulinux-snapshots-$boot_uuid' {"
-				fi
+                fi
-				entry "\
+                entry "\
-		if [ x\$feature_all_video_module = xy ]; then
+        if [ x\$feature_all_video_module = xy ]; then
-		insmod all_video
+        insmod all_video
-		fi
+        fi
-		set gfxpayload=keep
+        set gfxpayload=keep
-		insmod ${boot_fs}
+        insmod ${boot_fs}
-		if [ x\$feature_platform_search_hint = xy ]; then
+        if [ x\$feature_platform_search_hint = xy ]; then
-			search --no-floppy --fs-uuid  --set=root ${boot_hs} ${boot_uuid}
+            search --no-floppy --fs-uuid  --set=root ${boot_hs} ${boot_uuid}
-		else
+        else
-			search --no-floppy --fs-uuid  --set=root ${boot_uuid}
+            search --no-floppy --fs-uuid  --set=root ${boot_uuid}
-		fi
+        fi
-		echo 'Loading Snapshot: "${snap_date_time}" "${snap_dir_name}"'
+        echo 'Loading Snapshot: "${snap_date_time}" "${snap_dir_name}"'
-		echo 'Loading Kernel: "${k}" ...'
+        echo 'Loading Kernel: "${k}" ...'
-		linux \"${boot_dir_root_grub}/"${k}"\" root="${LINUX_ROOT_DEVICE}" rw rootflags=subvol=\""${snap_dir_name}"\" ${kernel_parameters}"
+        linux \"${boot_dir_root_grub}/"${k}"\" root="${LINUX_ROOT_DEVICE}" ${kernel_parameters} ${rootflags}subvol=\""${snap_dir_name}"\""
-				if [[ -f "${boot_dir}"/"${u}" && "${i}" != "${prefix_i}-${kversion}-${alt_suffix_i}" ]] ; then
+                if [[ "${name_microcode}" != "x" ]] ; then
-					entry "\
+                    entry "\
-		echo 'Loading Microcode & Initramfs: "${u}" "${i}" ...'
+        echo 'Loading Microcode & Initramfs: "${u}" "${i}" ...'
-		initrd \"${boot_dir_root_grub}/"${u}"\" \"${boot_dir_root_grub}/"${i}"\""
+        initrd \"${boot_dir_root_grub}/"${u}"\" \"${boot_dir_root_grub}/"${i}"\""
-				else
+                else
-					entry "\
+                    entry "\
-		echo 'Loading Initramfs: "${i}" ...'
+        echo 'Loading Initramfs: "${i}" ...'
-		initrd \"${boot_dir_root_grub}/"${i}"\""
+        initrd \"${boot_dir_root_grub}/"${i}"\""
-				fi
+                fi
-	entry "	}"
+                entry "    }"
-				count_warning_menuentries=$((1+$count_warning_menuentries))
+                count_warning_menuentries=$((1+$count_warning_menuentries))
-			done
+            done
-		done
+        done
-	done
+    done
-	entry  "}"
+    entry  "}"
 }
 
 ## Trim a string from leading and trailing whitespaces
 trim() {
-	local var="$*"
+    local var="$*"
-	var="${var#"${var%%[![:space:]]*}"}"
+    var="${var#"${var%%[![:space:]]*}"}"
-	var="${var%"${var##*[![:space:]]}"}"
+    var="${var%"${var##*[![:space:]]}"}"
-	echo -n "$var"
+    echo -n "$var"
 }
 
 ## List of snapshots on filesystem
 snapshot_list()
 {
-	# Query info from snapper if it is installed
+    # Query info from snapper if it is installed
-	type snapper >/dev/null 2>&1
+    type snapper >/dev/null 2>&1
-	if [[ $? -eq 0 ]]; then
+    if [ $? -eq 0 ]; then
-		local snapper_ids=($(snapper --no-dbus -t 0 -c "$snapper_config" list | tail -n +3 | cut -d'|' -f 1))
+        if [ -s "/etc/snapper/configs/$snapper_config" ]; then
-		local snapper_types=($(snapper --no-dbus -t 0 -c "$snapper_config" list | tail -n +3 | cut -d'|' -f 2))
+            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=$'\n'
+            IFS=$'\n'
-		local snapper_descriptions=($(snapper --no-dbus -t 0 -c "$snapper_config" list | tail -n +3 | rev | cut -d'|' -f 2 | rev))
+            local snapper_descriptions=($(snapper --no-dbus -t 0 -c "$snapper_config" list --disable-used-space | tail -n +3 | rev | cut -d'|' -f 2 | rev))
-	fi
+        else
+            printf "Warning: snapper detected but config '$snapper_config' does not exist\n" >&2
+        fi
+    fi
 
-	IFS=$'\n'
+    IFS=$'\n'
 
-	# Parse btrfs snapshots
+    # Parse btrfs snapshots
-	local entries=()
+    local entries=()
-	local ids=()
+    local ids=()
-	local max_entry_length=0
+    local max_entry_length=0
-	for snap in $(btrfs subvolume list -sa "${btrfssubvolsort}" /); do
+    for snap in $(btrfs subvolume list -sa "${btrfssubvolsort}" /); do
-		IFS=$oldIFS
+        IFS=$oldIFS
-		snap=($snap)
+        snap=($snap)
-		local snap_path_name=${snap[@]:13:${#snap[@]}}
+        local snap_path_name=${snap[@]:13:${#snap[@]}}
 
-		# Discard deleted snapshots
+        # Discard deleted snapshots
-		if [ "$snap_path_name" = "DELETED" ]; then continue; fi
+        if [ "$snap_path_name" = "DELETED" ]; then continue; fi
-		[[ ${snap_path_name%%"/"*} == "<FS_TREE>" ]] && snap_path_name=${snap_path_name#*"/"}
+        [[ ${snap_path_name%%"/"*} == "<FS_TREE>" ]] && snap_path_name=${snap_path_name#*"/"}
 
-		# ignore specific path during run "grub-mkconfig"
+        # ignore specific path during run "grub-mkconfig"
-		if [ ! -z "${ignore_specific_path}" ] ; then
+        if [ ! -z "${GRUB_BTRFS_IGNORE_SPECIFIC_PATH}" ] ; then
-			for isp in ${ignore_specific_path[@]} ; do
+            for isp in ${GRUB_BTRFS_IGNORE_SPECIFIC_PATH[@]} ; do
-				[[ "${snap_path_name}" == "${isp}"/* ]] && continue 2;
+                [[ "${snap_path_name}" == "${isp}" ]] && continue 2;
-			done
+            done
-		fi
+        fi
+        if [ ! -z "${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
+        # detect if /boot directory exists
-		[[ ! -d "$gbgmp/$snap_path_name/boot" ]] && continue;
+        [[ ! -d "$gbgmp/$snap_path_name/boot" ]] && continue;
 
-		local id="${snap_path_name//[!0-9]}" # brutal way to get id: remove everything non-numeric
+        local id="${snap_path_name//[!0-9]}" # brutal way to get id: remove everything non-numeric
-		ids+=("$id")
+        ids+=("$id")
 
-		local entry="${snap[@]:10:2} | ${snap_path_name}"
+        local entry="${snap[@]:10:2} | ${snap_path_name}"
-		entries+=("$entry")
+        entries+=("$entry")
 
-		# Find max length of a snapshot entry, needed for pretty formatting
+        # Find max length of a snapshot entry, needed for pretty formatting
-		local length="${#entry}"
+        local length="${#entry}"
-		[[ "$length" -gt "$max_entry_length" ]] && max_entry_length=$length
+        [[ "$length" -gt "$max_entry_length" ]] && max_entry_length=$length
-	done
+    done
 
-	# Find max length of a snapshot type, needed for pretty formatting
+    # Find max length of a snapshot type, needed for pretty formatting
-	local max_type_length=0
+    local max_type_length=0
-	for id in "${ids[@]}"; do
+    for id in "${ids[@]}"; do
-		for j in "${!snapper_ids[@]}"; do
+        for j in "${!snapper_ids[@]}"; do
-			local snapper_id="${snapper_ids[$j]//[[:space:]]/}"
+            local snapper_id="${snapper_ids[$j]//[[:space:]]/}"
-			if [[ "$snapper_id" == "$id" ]]; then
+            if [[ "$snapper_id" == "$id" ]]; then
-				local snapper_type=$(trim "${snapper_types[$j]}")
+                local snapper_type=$(trim "${snapper_types[$j]}")
-				local length="${#snapper_type}"
+                local length="${#snapper_type}"
-				[[ "$length" -gt "$max_type_length" ]] && max_type_length=$length
+                [[ "$length" -gt "$max_type_length" ]] && max_type_length=$length
-			fi
+            fi
-		done
+        done
-	done
+    done
 
-	for i in "${!entries[@]}"; do
+    for i in "${!entries[@]}"; do
-		local id="${ids[$i]}"
+        local id="${ids[$i]}"
-		local entry="${entries[$i]}"
+        local entry="${entries[$i]}"
-		for j in "${!snapper_ids[@]}"; do
+        for j in "${!snapper_ids[@]}"; do
-			local snapper_id="${snapper_ids[$j]//[[:space:]]/}"
+            local snapper_id="${snapper_ids[$j]//[[:space:]]/}"
-			# remove other non numeric characters
+            # remove other non numeric characters
-			snapper_id="${snapper_id//\*/}"
+            snapper_id="${snapper_id//\*/}"
-			snapper_id="${snapper_id//\+/}"
+            snapper_id="${snapper_id//\+/}"
-			snapper_id="${snapper_id//-/}"
+            snapper_id="${snapper_id//-/}"
-			if [[ "$snapper_id" == "$id" ]]; then
+            if [[ "$snapper_id" == "$id" ]]; then
-				local snapper_type=$(trim "${snapper_types[$j]}")
+                local snapper_type=$(trim "${snapper_types[$j]}")
-				local snapper_description=$(trim "${snapper_descriptions[$j]}")
+                local snapper_description=$(trim "${snapper_descriptions[$j]}")
-				printf -v entry "%-${max_entry_length}s | %-${max_type_length}s | %s" "$entry" "$snapper_type" "$snapper_description"
+                printf -v entry "%-${max_entry_length}s | %-${max_type_length}s | %s" "$entry" "$snapper_type" "$snapper_description"
-				break
+                break
-			fi
+            fi
-		done
+        done
-		echo "$entry"
+        echo "$entry"
-	done
+    done
 
-	IFS=$oldIFS
+    IFS=$oldIFS
 }
 
 ## Detect kernels in "/boot"
 detect_kernel()
 {
-	list_kernel=()
+    list_kernel=()
-	# Original kernel (auto-detect)
+    # Original kernel (auto-detect)
-	for okernel in	"${boot_dir}"/vmlinuz-* \
+    for okernel in  "${boot_dir}"/vmlinuz-* \
-			"${boot_dir}"/vmlinux-* \
+                    "${boot_dir}"/vmlinux-* \
-			"${boot_dir}"/kernel-* ; do
+                    "${boot_dir}"/kernel-* ; do
-		[[ ! -f "${okernel}" ]] && continue;
+        [[ ! -f "${okernel}" ]] && continue;
-		list_kernel+=("$okernel")
+        list_kernel+=("$okernel")
-	done
+    done
 
-	# Custom name kernel in GRUB_BTRFS_NKERNEL
+    # Custom name kernel in GRUB_BTRFS_NKERNEL
-	if [ ! -z "${nkernel}" ] ; then
+    if [ ! -z "${GRUB_BTRFS_NKERNEL}" ] ; then
-		for ckernel in "${boot_dir}/${nkernel[@]}" ; do
+        for ckernel in "${boot_dir}/${GRUB_BTRFS_NKERNEL[@]}" ; do
-			[[ ! -f "${ckernel}" ]] && continue;
+            [[ ! -f "${ckernel}" ]] && continue;
-			list_kernel+=("$ckernel")
+            list_kernel+=("$ckernel")
-		done
+        done
-	fi
+    fi
 }
 
 ## Detect initramfs in "/boot"
 detect_initramfs()
 {
-	list_initramfs=()
+    list_initramfs=()
-	# Original initramfs (auto-detect)
+    # Original initramfs (auto-detect)
-	for oinitramfs in	"${boot_dir}"/initrd.img-* \
+    for oinitramfs in   "${boot_dir}"/initrd.img-* \
-				"${boot_dir}"/initrd-*.img \
+                        "${boot_dir}"/initrd-*.img \
-				"${boot_dir}"/initrd-*.gz \
+                        "${boot_dir}"/initrd-*.gz \
-				"${boot_dir}"/initramfs-*.img \
+                        "${boot_dir}"/initramfs-*.img \
-				"${boot_dir}"/initramfs-*.gz ; do
+                        "${boot_dir}"/initramfs-*.gz ; do
-		[[ ! -f "${oinitramfs}" ]] && continue;
+        [[ ! -f "${oinitramfs}" ]] && continue;
-		list_initramfs+=("$oinitramfs")
+        list_initramfs+=("$oinitramfs")
-	done
+    done
 
-	# Custom name initramfs in GRUB_BTRFS_NINIT
+    # Custom name initramfs in GRUB_BTRFS_NINIT
-	if [ ! -z "$ninit" ] ; then
+    if [ ! -z "${GRUB_BTRFS_NINIT}" ] ; then
-		for cinitramfs in "${boot_dir}/${ninit[@]}" ; do
+        for cinitramfs in "${boot_dir}/${GRUB_BTRFS_NINIT[@]}" ; do
-			[[ ! -f "${cinitramfs}" ]] && continue;
+            [[ ! -f "${cinitramfs}" ]] && continue;
-			list_initramfs+=("$cinitramfs")
+            list_initramfs+=("$cinitramfs")
-		done
+        done
-	fi
+    fi
 }
 
 ## Detect microcode in "/boot"
 detect_microcode()
 {
-	list_ucode=()
+    list_ucode=()
-	# Original intel microcode
+    # Original intel/amd microcode (auto-detect)
-	for oiucode in "${boot_dir}"/intel-ucode.img ; do
+    # See "https://www.gnu.org/software/grub/manual/grub/html_node/Simple-configuration.html"
-		[[ ! -f "${oiucode}" ]] && continue;
+    for oiucode in  "${boot_dir}"/intel-uc.img \
-		list_ucode+=("$oiucode")
+                    "${boot_dir}"/intel-ucode.img \
-	done
+                    "${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_CUSTOM_MICROCODE
-	if [ ! -z "$microcode" ] ; then
+    if [ ! -z "${GRUB_BTRFS_CUSTOM_MICROCODE}" ] ; then
-		for cucode in "${boot_dir}/${microcode[@]}" ; do
+        for cucode in "${boot_dir}/${GRUB_BTRFS_CUSTOM_MICROCODE[@]}" ; do
-			[[ ! -f "${cucode}" ]] && continue
+            [[ ! -f "${cucode}" ]] && continue
-			list_ucode+=("$cucode")
+            list_ucode+=("$cucode")
-		done
+        done
-	fi
+    fi
-	if [ -z "${list_ucode}" ]; then list_ucode=(x); fi
+    if [ -z "${list_ucode}" ]; then list_ucode=(x); fi
 }
 
 ## Show full path snapshot or only name
 path_snapshot()
 {
-	case "${path_snapshot}" in
+    case "${GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT:-"true"}" in
-		true) name_snapshot=("${snap_full_name}");;
+        true) name_snapshot=("${snap_full_name}");;
-		*) name_snapshot=("${snap_full_name#*"/"}")
+        *)    name_snapshot=("${snap_full_name#*"/"}")
-	esac
+    esac
 }
 
 ## Title format in grub-menu
 title_format()
 {
-	case "${title_format}" in
+    case "${GRUB_BTRFS_TITLE_FORMAT:-"p/d/n"}" in
-		p/n/d) 	title_menu="${prefixentry} ${name_snapshot} ${snap_date_time}";;
+        p/n/d)  title_menu="${prefixentry} ${name_snapshot} ${snap_date_time}";;
-		p/d) 	title_menu="${prefixentry} ${snap_date_time}";;
+        p/d)    title_menu="${prefixentry} ${snap_date_time}";;
-		p/n) 	title_menu="${prefixentry} ${name_snapshot}";;
+        p/n)    title_menu="${prefixentry} ${name_snapshot}";;
-		d/n) 	title_menu="${snap_date_time} ${name_snapshot}";;
+        d/n)    title_menu="${snap_date_time} ${name_snapshot}";;
-		n/d) 	title_menu="${name_snapshot} ${snap_date_time}";;
+        n/d)    title_menu="${name_snapshot} ${snap_date_time}";;
-		p) 		title_menu="${prefixentry}";;
+        p)      title_menu="${prefixentry}";;
-		d)		title_menu="${snap_date_time}";;
+        d)      title_menu="${snap_date_time}";;
-		n)		title_menu="${name_snapshot}";;
+        n)      title_menu="${name_snapshot}";;
-		*)		title_menu="${prefixentry} ${snap_date_time} ${name_snapshot}"
+        *)      title_menu="${prefixentry} ${snap_date_time} ${name_snapshot}"
-	esac
+    esac
 }
 
 ## List of kernels, initramfs and microcode in snapshots
 boot_bounded()
 {
-	# Initialize menu entries
+    # Initialize menu entries
-	IFS=$'\n'
+    IFS=$'\n'
-	for item in $(snapshot_list); do
+    for item in $(snapshot_list); do
-		# fix: limit_snap_show=0
+        [[ ${limit_snap_show} -le 0 ]] && break; # fix: limit_snap_show=0
-		[[ ${limit_snap_show} -le 0 ]] && break;
+        IFS=$oldIFS
-		IFS=$oldIFS
+        snap_full_name="$(echo "$item" | cut -d'|' -f2-)" # do not trim it to keep nice formatting
-		snap_full_name="$(echo "$item" | cut -d'|' -f2-)" # do not trim it to keep nice formatting
+        snap_dir_name="$(echo "$item" | cut -d'|' -f2)"
-		snap_dir_name="$(echo "$item" | cut -d'|' -f2)"
+        snap_dir_name="$(trim "$snap_dir_name")"
-		snap_dir_name="$(trim "$snap_dir_name")"
+        snap_date_time="$(echo "$item" | cut -d' ' -f1-2)"
-		snap_date_time="$(echo "$item" | cut -d' ' -f1-2)"
+        snap_date_time="$(trim "$snap_date_time")"
-		snap_date_time="$(trim "$snap_date_time")"
+        
-
+        boot_dir="$gbgmp/$snap_dir_name$boot_directory"
-		boot_dir="$gbgmp/$snap_dir_name/boot"
+        # Kernel (Original + custom kernel)
-		# Kernel (Original + custom kernel)
+        detect_kernel
-		detect_kernel
+        if [ -z "${list_kernel}" ]; then continue; fi
-		if [ -z "${list_kernel}" ]; then continue; fi
+        name_kernel=("${list_kernel[@]##*"/"}")
-		name_kernel=("${list_kernel[@]##*"/"}")
+        # Detect rootflags
-		# Initramfs (Original + custom initramfs)
+        detect_rootflags
-		detect_initramfs
+        # Initramfs (Original + custom initramfs)
-		if [ -z "${list_initramfs}" ]; then continue; fi
+        detect_initramfs
-		name_initramfs=("${list_initramfs[@]##*"/"}")
+        if [ -z "${list_initramfs}" ]; then continue; fi
-		# microcode (intel-ucode + custom microcode)
+        name_initramfs=("${list_initramfs[@]##*"/"}")
-		detect_microcode
+        # microcode (auto-detect + custom microcode)
-		name_microcode=("${list_ucode[@]##*"/"}")
+        detect_microcode
-		# show snapshot found during run "grub-mkconfig"
+        name_microcode=("${list_ucode[@]##*"/"}")
-		if [[ "${show_snap_found}" = "true" ]]; then
+        # show snapshot found during run "grub-mkconfig"
-		printf $"# Found snapshot: %s\n" "$item" >&2 ;
+        if [[ "${GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND:-"true"}" = "true" ]]; then
-		fi
+            printf "Found snapshot: %s\n" "$item" >&2 ;
-		# Show full path snapshot or only name
+        fi
-		path_snapshot
+        # Show full path snapshot or only name
-		# Title format in grub-menu
+        path_snapshot
-		title_format
+        # Title format in grub-menu
-		# convert /boot directory to root of GRUB (e.g /boot become /)
+        title_format
-		boot_dir_root_grub="$(make_system_path_relative_to_its_root "${boot_dir}")"
+        # convert /boot directory to root of GRUB (e.g /boot become /)
-		# Make menuentries
+        boot_dir_root_grub="$(make_system_path_relative_to_its_root "${boot_dir}")"
-		make_menu_entries
+        # Make menuentries
-		### Limit snapshots found during run "grub-mkconfig"
+        make_menu_entries
-	        count_limit_snap=$((1+$count_limit_snap))
+        ### Limit snapshots found during run "grub-mkconfig"
-	        [[ $count_limit_snap -ge $limit_snap_show ]] && break;
+        count_limit_snap=$((1+$count_limit_snap))
-		# Limit generation of menuentries if exceeds 250
+        [[ $count_limit_snap -ge $limit_snap_show ]] && break;
-		# [[ $count_warning_menuentries -ge 250 ]] && break;
+        # Limit generation of menuentries if exceeds 250
-	done
+        # [[ $count_warning_menuentries -ge 250 ]] && break;
-	IFS=$oldIFS
+    done
+    IFS=$oldIFS
 }
 boot_separate()
 {
-	boot_dir="/boot"
+    boot_dir="${boot_directory}"
-	# convert /boot directory to root of GRUB (e.g /boot become /)
+    # convert /boot directory to root of GRUB (e.g /boot become /)
-	boot_dir_root_grub="$(make_system_path_relative_to_its_root "${boot_dir}")"
+    boot_dir_root_grub="$(make_system_path_relative_to_its_root "${boot_dir}")"
 
-	# Kernel (Original + custom kernel)
+    # Kernel (Original + custom kernel)
-	detect_kernel
+    detect_kernel
-	if [ -z "${list_kernel}" ]; then print_error "Kernels not found."; fi
+    if [ -z "${list_kernel}" ]; then print_error "Kernels not found."; fi
-	name_kernel=("${list_kernel[@]##*"/"}")
+    name_kernel=("${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[@]##*"/"}")
 
-	# Initramfs (Original + custom initramfs)
+    # Initialize menu entries
-	detect_initramfs
+    IFS=$'\n'
-	if [ -z "${list_initramfs}" ]; then print_error "Initramfs not found."; fi
+    for item in $(snapshot_list); do
-	name_initramfs=("${list_initramfs[@]##*"/"}")
+        [[ ${limit_snap_show} -le 0 ]] && break; # fix: limit_snap_show=0
-
+        IFS=$oldIFS
-	# microcode (auto-detect + custom microcode)
+        snap_full_name="$(echo "$item" | cut -d'|' -f2-)" # do not trim it to keep nice formatting
-	detect_microcode
+        snap_dir_name="$(echo "$item" | cut -d'|' -f2)"
-	name_microcode=("${list_ucode[@]##*"/"}")
+        snap_dir_name="$(trim "$snap_dir_name")"
-
+        snap_date_time="$(echo "$item" | cut -d' ' -f1-2)"
-	# Initialize menu entries
+        snap_date_time="$(trim "$snap_date_time")"
-	IFS=$'\n'
+        # Detect rootflags
-	for item in $(snapshot_list); do
+        detect_rootflags
-		# fix: limit_snap_show=0
+        # show snapshot found during run "grub-mkconfig"
-		[[ ${limit_snap_show} -le 0 ]] && break;
+        if [[ "${GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND:-"true"}" = "true" ]]; then
-		IFS=$oldIFS
+            printf "Found snapshot: %s\n" "$item" >&2 ;
-		snap_full_name="$(echo "$item" | cut -d'|' -f2-)" # do not trim it to keep nice formatting
+        fi
-		snap_dir_name="$(echo "$item" | cut -d'|' -f2)"
+        # Show full path snapshot or only name
-		snap_dir_name="$(trim "$snap_dir_name")"
+        path_snapshot
-		snap_date_time="$(echo "$item" | cut -d' ' -f1-2)"
+        # Title format in grub-menu
-		snap_date_time="$(trim "$snap_date_time")"
+        title_format
-		# show snapshot found during run "grub-mkconfig"
+        # Make menuentries
-		if [[ "${show_snap_found}" = "true" ]]; then
+        make_menu_entries
-		printf $"# Found snapshot: %s\n" "$item" >&2 ;
+        # Limit snapshots found during run "grub-mkconfig"
-		fi
+        count_limit_snap=$((1+$count_limit_snap))
-		# Show full path snapshot or only name
+        [[ $count_limit_snap -ge $limit_snap_show ]] && break;
-		path_snapshot
+        # Limit generation of menuentries if exceeds 250
-		# Title format in grub-menu
+        # [[ $count_warning_menuentries -ge 250 ]] && break;
-		title_format
+    done
-		# Make menuentries
+    IFS=$oldIFS
-		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 ###
+### Start
-printf "###### - Grub-btrfs: Snapshot detection started - ######\n" >&2 ;
+printf "Detecting snapshots ...\n" >&2 ;
-# if btrfs prog isn't installed, exit
+# Only support btrfs snapshots
 test_btrfs
 # Delete existing config
-#rm -f --preserve-root "/boot/$grub_directory/grub-btrfs.cfg"
+#rm -f --preserve-root "$grub_directory/grub-btrfs.cfg"
-> "/boot/$grub_directory/grub-btrfs.cfg"
+> "$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 $gbgmp/
@@ -520,37 +519,35 @@ count_limit_snap=0
 # detect uuid requirement
 check_uuid_required
 # Detects if /boot is a separate partition
-if [[ "$override_boot_partition_detection" == "true" ]]; then
+if [[ "${GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION:-"false"}" == "true" ]]; then
-	printf "# Info: Override boot partition detection : enable \n" >&2 ;
+    printf "Info: Override boot partition detection : enable \n" >&2 ;
-	boot_separate
+    boot_separate
-	else
+else
-	if [[ "$root_uuid" != "$boot_uuid" ]]; then
+    if [[ "$root_uuid" != "$boot_uuid" ]]; then
-		printf "# Info: Separate boot partition detected \n" >&2 ;
+        printf "Info: Separate boot partition detected \n" >&2 ;
-		boot_separate
+        boot_separate
-		else
+    else
-		printf "# Info: Separate boot partition not detected \n" >&2 ;
+        printf "Info: Separate boot partition not detected \n" >&2 ;
-		boot_bounded
+        boot_bounded
-	fi
+    fi
 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 ;
+[[ $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 ;
+# 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
+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 ;
+    printf "Found ${count_limit_snap} snapshot(s)\n" >&2 ;
 fi
 # if no snapshot found, exit
 if [[ "${count_limit_snap}" = "0" || -z "${count_limit_snap}" ]]; then
-	print_error "No snapshots found."
+    print_error "No snapshots found."
 fi
-root_grub="$(make_system_path_relative_to_its_root /boot/$grub_directory)"
 # Make a submenu in GRUB (grub.cfg)
 cat << EOF
-submenu '${submenuname}' {
+submenu '${submenuname}' ${protection_authorized_users}${unrestricted_access_submenu}{
-	configfile "\${prefix}/grub-btrfs.cfg"
+    configfile "\${prefix}/grub-btrfs.cfg"
 }
 EOF
-printf "###### - Grub-btrfs: Snapshot detection ended   - ######\n" >&2 ;
+### End
-### End ###

Makefile

@@ -4,7 +4,7 @@ PREFIX ?= /usr
 SHARE_DIR = $(DESTDIR)$(PREFIX)/share
 LIB_DIR = $(DESTDIR)$(PREFIX)/lib
 
-.PHONY: install
+.PHONY: install uninstall help
 
 install:
 	@install -Dm755 -t "$(DESTDIR)/etc/grub.d/" 41_snapshots-btrfs
@@ -12,3 +12,49 @@ install:
 	@install -Dm644 -t "$(LIB_DIR)/systemd/system/" grub-btrfs.service
 	@install -Dm644 -t "$(LIB_DIR)/systemd/system/" grub-btrfs.path
 	@install -Dm644 -t "$(SHARE_DIR)/licenses/$(PKGNAME)/" LICENSE
+	@# Arch Linux like distros only :
+	@if command -V mkinitcpio >/dev/null 2>&1; then \
+		install -Dm644 "initramfs/Arch Linux/overlay_snap_ro-install" "$(LIB_DIR)/initcpio/install/grub-btrfs-overlayfs"; \
+		install -Dm644 "initramfs/Arch Linux/overlay_snap_ro-hook" "$(LIB_DIR)/initcpio/hooks/grub-btrfs-overlayfs"; \
+	 fi
+	@install -Dm644 -t "$(SHARE_DIR)/doc/$(PKGNAME)/" README.md
+	@install -Dm644 "initramfs/readme.md" "$(SHARE_DIR)/doc/$(PKGNAME)/initramfs-overlayfs.md"
+
+uninstall:
+	@grub_dirname="$$(grep -oP '^[[:space:]]*GRUB_BTRFS_GRUB_DIRNAME=\K.*' "$(DESTDIR)/etc/default/grub-btrfs/config" | sed "s|\s*#.*||;s|(\s*\(.\+\)\s*)|\1|;s|['\"]||g")"; \
+	 rm -f "$${grub_dirname:-/boot/grub}/grub-btrfs.cfg"
+	@rm -f "$(DESTDIR)/etc/default/grub-btrfs/config"
+	@rm -f "$(DESTDIR)/etc/grub.d/41_snapshots-btrfs"
+	@rm -f "$(LIB_DIR)/systemd/system/grub-btrfs.service"
+	@rm -f "$(LIB_DIR)/systemd/system/grub-btrfs.path"
+	@rm -f "$(LIB_DIR)/initcpio/install/grub-btrfs-overlayfs"
+	@rm -f "$(LIB_DIR)/initcpio/hooks/grub-btrfs-overlayfs"
+	@# Arch Linux unlike distros only :
+	@if ! command -V mkinitcpio >/dev/null 2>&1; then \
+		rmdir --ignore-fail-on-non-empty "$(LIB_DIR)/initcpio/install" || :; \
+		rmdir --ignore-fail-on-non-empty "$(LIB_DIR)/initcpio/hooks" || :; \
+		rmdir --ignore-fail-on-non-empty "$(LIB_DIR)/initcpio" || :; \
+	 fi
+	@rm -f "$(SHARE_DIR)/doc/$(PKGNAME)/README.md"
+	@rm -f "$(SHARE_DIR)/doc/$(PKGNAME)/initramfs-overlayfs.md"
+	@rm -f "$(SHARE_DIR)/licenses/$(PKGNAME)/LICENSE"
+	@rmdir --ignore-fail-on-non-empty "$(SHARE_DIR)/doc/$(PKGNAME)/" || :
+	@rmdir --ignore-fail-on-non-empty "$(SHARE_DIR)/licenses/$(PKGNAME)/" || :
+	@rmdir --ignore-fail-on-non-empty "$(DESTDIR)/etc/default/grub-btrfs" || :
+
+help:
+	@echo
+	@echo "Usage: $(MAKE) [ <parameter>=<value> ... ] [ <action> ]"
+	@echo
+	@echo "  actions: install"
+	@echo "           uninstall"
+	@echo "           help"
+	@echo
+	@echo "  parameters | description                    | defaults"
+	@echo "  -----------+--------------------------------+----------------------------"
+	@echo "  DESTDIR    | install destination            | <unset>"
+	@echo "  PREFIX     | system tree prefix             | '/usr'"
+	@echo "  SHARE_DIR  | shared data location           | '\$$(DESTDIR)\$$(PREFIX)/share'"
+	@echo "  LIB_DIR    | system libraries location      | '\$$(DESTDIR)\$$(PREFIX)/lib'"
+	@echo "  PKGNAME    | name of the ditributed package | 'grub-btrfs'"
+	@echo

README.md

@@ -9,19 +9,27 @@ This is a version 4.xx of grub-btrfs
 ### Description
 Improves Grub by adding "btrfs snapshots" to the Grub menu.
 
-You can start your system on a "snapshot" from the Grub menu.
+You can start your system on a "snapshot" from the Grub menu.  
-
 Supports manual snapshots, snapper, timeshift ...
 
-##### Warning : it isn't recommended to start on read-only snapshot
+##### Warning: booting on read-only snapshots can be tricky
+
+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.
+
+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 microcode in "/boot" directory on snapshots.
+* 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
@@ -30,120 +38,42 @@ Supports manual snapshots, snapper, timeshift ...
 pacman -S grub-btrfs
 ```
 
-### Manual
+#### Manual
 
 * 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.
+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`.
+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_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, weird reaction with snapper.
-	
-* 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="50"
-
-	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 number of snapshots found during run "grub-mkconfig".
-
-* GRUB_BTRFS_NKERNEL=("kernel-custom")
-
-	Use it only if you have a custom kernel name
-
-* GRUB_BTRFS_NINIT=("initramfs-custom.img" "initrd.img-custom")
-
-	Use it only if you have a custom initramfs name.
-
-* GRUB_BTRFS_INTEL_UCODE=("intel-ucode.img")
-
-	Use it only if you have custom intel-ucode.
-
-* 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"													
-
-	Snapper's config name to use.
-
-* GRUB_BTRFS_DISABLE="false"
-
-	Disable grub-btrfs.
-
-* GRUB_BTRFS_DIRNAME="grub"
-
-	Name of the grub folder in `/boot/`, might be grub2 on some distributions.
-
-* GRUB_BTRFS_OVERRIDE_BOOT_PARTITION_DETECTION="false"
-
-	Change to "true" if you have a boot partition in a different subvolume.
-
-* GRUB_BTRFS_MKCONFIG=grub-mkconfig
-
-	Name or path of the 'grub-mkconfig' executable; might be 'grub2-mkconfig' on some distributions.
-	
 ##
 ### Automatically update grub
-If you would like Grub to automatically update when a snapshots is made or deleted:
+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`.
-* Use `systemctl start/enable grub-btrfs.path`
+* `grub-btrfs.path` automatically (re)generates `grub.cfg` when a modification appears in `/.snapshots` folder (by default).
-* `grub-btrfs.path` automatically (re)generate `grub.cfg` when a modification appear in `/.snapshots`
+* 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.
+
+		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`.
+##### Warning:
+by default, `grub-mkconfig` command is used.  
+Might be `grub2-mkconfig` on some systems (Fedora ...).   
+Edit `GRUB_BTRFS_MKCONFIG` variable in `/etc/default/grub-btrfs/config` file to reflect this.
 ##
 ### Special thanks for assistance and contributions
 * [maximbaz](https://github.com/maximbaz)
-* [crossroads1112](https://github.com/crossroads1112)
+* [All contributors](https://github.com/Antynea/grub-btrfs/graphs/contributors)
-* [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

@@ -1,76 +1,122 @@
 #!/usr/bin/env bash
 
-# Name appearing in the Grub menu
+# Disable grub-btrfs.
-# Default: "Arch Linux snapshots"
+# 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
+# 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
+# Show full path snapshot or only name in the Grub menu, weird reaction with snapper.
 # Default: "true"
-#GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="true"
+#GRUB_BTRFS_DISPLAY_PATH_SNAPSHOT="false"
 
-# Custom title
+# Custom title.
-# shows/hides p"prefix" d"date" n"name" in the Grub menu, separator "/", custom order available
+# 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
+# Limit the number of snapshots populated in the GRUB menu.
 # Default: "50"
 #GRUB_BTRFS_LIMIT="50"
 
-# Sort the found subvolumes by newest first ("descending") or oldest first ("ascending") and show $GRUB_BTRFS_LIMIT first entries.
+# Sort the found subvolumes by "ogeneration" or "generation" or "path" or "rootid".
-# Default: "descending"
+# # See Sorting section to https://btrfs.wiki.kernel.org/index.php/Manpage/btrfs-subvolume#SUBCOMMAND
-#GRUB_BTRFS_SUBVOLUME_SORT="descending"
+# "-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="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"
 
-# Use only if you have custom kernel name
+# By default, "grub-btrfs" automatically detects most existing kernels.
-# Default:
+# If you have one or more custom kernels, you can add them here.
-#GRUB_BTRFS_NKERNEL=("vmlinuz-linux")
+# Default: ("")
+#GRUB_BTRFS_NKERNEL=("kernel-custom" "vmlinux-custom")
 
-# Use only if you have custom initramfs name
+# By default, "grub-btrfs" automatically detects most existing initramfs.
-# Default:
+# If you have one or more custom initramfs, you can add them here.
-#GRUB_BTRFS_NINIT=("initramfs-linux.img" "initramfs-linux-fallback.img")
+# Default: ("")
+#GRUB_BTRFS_NINIT=("initramfs-custom.img" "initrd-custom.img" "otherinit-custom.gz")
 
-# Use only if you have custom intel-ucode
+# By default, "grub-btrfs" automatically detects most existing microcodes.
-# Default:
+# If you have one or more custom microcodes, you can add them here.
-#GRUB_BTRFS_INTEL_UCODE=("intel-ucode.img")
+# Default: ("")
+#GRUB_BTRFS_CUSTOM_MICROCODE=("custom-ucode.img" "custom-uc.img "custom_ucode.cpio")
+
+# Comma seperated mount options to be used when booting a snapshot.
+# They can be defined here as well as in the "/" line inside the respective snapshots'
+# "/etc/fstab" files.  Mount options found in both places are combined, and this variable
+# takes priority over `fstab` entries.
+# NB: Do NOT include "subvol=..." or "subvolid=..." here.
+# Default: ""
+#GRUB_BTRFS_ROOTFLAGS="space_cache,commit=10,norecovery"
 
 # 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/...
+# Only exact paths are ignored.
-# use : GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker");
+# e.g : if `specific path` = @, only `@` snapshot will be ignored.
-# If path is a subvolume, # Found Snapshot: 2016-03-31 10:24:41 @var/lib/docker/btrfs/subvolumes/...
+# Default: ("@")
-# use : GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@var/lib/docker");
+GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("@")
-# 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")
 
+# 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 command, use by "grub-btrfs.service"
+# Might be 'grub2-mkconfig' on some systems (Fedora ...)
+# Default paths are /sbin:/bin:/usr/sbin:/usr/bin,
+# if your path is missing, report it on the upstream project.
+# For example, on Fedora : "/sbin/grub2-mkconfig"
+# You can use only name or full path.
+# Default: grub-mkconfig
+#GRUB_BTRFS_MKCONFIG=/usr/bin/grub2-mkconfig
+
+# Snapper
 # Snapper's config name to use
 # Default: "root"
 #GRUB_BTRFS_SNAPPER_CONFIG="root"
 
-# Disable Grub-btrfs
+# 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="false"
+#GRUB_BTRFS_DISABLE_PROTECTION_SUBMENU="true"
-
-# 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

grub-btrfs.service

@@ -8,4 +8,4 @@ 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'
+ExecStart=bash -c 'if [ -s "${GRUB_BTRFS_GRUB_DIRNAME:-/boot/grub}/grub-btrfs.cfg" ]; then /etc/grub.d/41_snapshots-btrfs; else ${GRUB_BTRFS_MKCONFIG:-grub-mkconfig} -o ${GRUB_BTRFS_GRUB_DIRNAME:-/boot/grub}/grub.cfg; fi' 

initramfs/Arch 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
+}

initramfs/Arch 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:

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.
+#