Make 'grub-mkconfig' command name configurable (#56)

* Make 'grub-mkconfig' command name configurable

- Use 'grub-mkconfig' as the default
- Note that some systems use 'grub2-mkconfig'
- Update 10-update_grub.conf to use the configurable grub directory name
- Refactor the systemd commands for clarity and to avoid duplicate regeneration on first run

* Update check_uuid_required() to work for partial regeneration of the GRUB menu

10-update_grub.conf

@@ -1,2 +1,7 @@
 [Service]
-ExecStartPost=/usr/sbin/grub-mkconfig -o /boot/grub/grub.cfg
+# Set the possible paths for `grub-mkconfig`
+Environment="PATH=/sbin:/bin:/usr/sbin:/usr/bin"
+# Load environment variables from the configuration
+EnvironmentFile=/etc/grub.d/41_snapshots-btrfs_config
+# Regenerate just '/boot/grub/grub-btrfs.cfg' if it exists, else regenerate the whole grub menu
+ExecStartPost=/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'

41_snapshots-btrfs

@@ -5,7 +5,7 @@
 # Written by: Antynea
 # BTC donation address: 1Lbvz244WA8xbpHek9W2Y12cakM6rDe5Rt
 # Github: https://github.com/Antynea/grub-btrfs
-#                                                                                                                                                                       #
+#
 # Purpose: Include btrfs snapshots at boot options (grub-menu).
 #
 # What this script does:
@@ -20,7 +20,7 @@
 # - Refer 41_snapshots-btrfs_config for the list of available options and their default values.
 # - Place your configurations to either /etc/grub.d/41_snapshots-btrfs_config or /etc/default/grub.
 #
-# - Generate grub.cfg (on Arch Linux use grub-mkconfig -o /boot/grub/grub.cfg)
+# - Generate grub.cfg (on Arch Linux use grub-mkconfig -o /boot/$grub_directory/grub.cfg)
 #
 # - grub-btrfs automatically generates snapshots entries.
 # - You will see it appear different entries (e.g : Snapshot: [2014-02-12 11:24:37] my snapshot name overkill)
@@ -83,8 +83,12 @@ show_snap_found=${GRUB_BTRFS_SHOW_SNAPSHOTS_FOUND:-"true"}
 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'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"}
 
 ########################
 ### variables script ###
@@ -92,14 +96,20 @@ snapper_config=${GRUB_BTRFS_SNAPPER_CONFIG:-"root"}
 ## Internationalization (default : english)
 export TEXTDOMAIN=grub-btrfs-git
 export TEXTDOMAINDIR="/usr/share/locale"
-## hints string
-hs_boot=$(${grub_probe} --target="hints_string" "/boot" 2>/dev/null)
-## UUID of the boot partition
-boot_uuid=$(${grub_probe} --target="fs_uuid" "/boot" 2>/dev/null)
-## Type filesystem of boot partition
+## Probe info "Boot partition"
+# Boot device
+boot_device=$(${grub_probe} --target=device "/boot")
+# hints string
+boot_hs=$(${grub_probe} --device "${boot_device}" --target="hints_string" 2>/dev/null)
+# UUID of the boot partition
+boot_uuid=$(${grub_probe} --device "${boot_device}" --target="fs_uuid" 2>/dev/null)
+# Type filesystem of boot partition
 boot_fs=$(${grub_probe} --target="fs" "/boot" 2>/dev/null)
-## UUID of the root partition
-root_uuid=$(${grub_probe} "/" --target="fs_uuid" 2>/dev/null)
+## Probe info "Root partition"
+# Root device
+root_device=$(${grub_probe} --target=device "/")
+# UUID of the root partition
+root_uuid=$(${grub_probe} --device "${root_device}" --target="fs_uuid" 2>/dev/null)
 ## Parameters passed to the kernel
 kernel_parameters="$GRUB_CMDLINE_LINUX $GRUB_CMDLINE_LINUX_DEFAULT"
 ## Mount point location
@@ -108,6 +118,16 @@ gbgmp=$(mktemp -d)
 CLASS="--class snapshots --class gnu-linux --class gnu --class os"
 ## save IFS
 oldIFS=$IFS
+## Detect uuid requirement (lvm,btrfs...)
+check_uuid_required() {
+if [ "x${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
+}
 
 
 ######################
@@ -137,10 +157,10 @@ test_btrfs()
 
 ## Create entry
 entry()	{
-echo "$@" >> "/boot/grub/grub-btrfs.cfg"
+echo "$@" >> "/boot/$grub_directory/grub-btrfs.cfg"
 # local arg="$@"
-# echo "${arg}" >> "/boot/grub/grub-btrfs.cfg"
-# cat << EOF >> "/boot/grub/grub-btrfs.cfg"
+# echo "${arg}" >> "/boot/$grub_directory/grub-btrfs.cfg"
+# cat << EOF >> "/boot/$grub_directory/grub-btrfs.cfg"
 # ${arg}
 # EOF
 }
@@ -179,13 +199,13 @@ make_menu_entries()
 		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}
+			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=UUID=${root_uuid} rw rootflags=subvol=\""${snap_dir_name}"\" ${kernel_parameters}"
+		linux \"${boot_dir_root_grub}/"${k}"\" root="${LINUX_ROOT_DEVICE}" rw rootflags=subvol=\""${snap_dir_name}"\" ${kernel_parameters}"
 				if [[ -f "${boot_dir}"/"${u}" && "${i}" != "${prefix_i}-${kversion}-${alt_suffix_i}" ]] ; then
 					entry "\
 		echo 'Loading Microcode & Initramfs: "${u}" "${i}" ...'
@@ -482,8 +502,8 @@ printf "###### - Grub-btrfs: Snapshot detection started - ######\n" >&2 ;
 # if btrfs prog isn't installed, exit
 test_btrfs
 # Delete existing config
-#rm -f --preserve-root "/boot/grub/grub-btrfs.cfg"
-> "/boot/grub/grub-btrfs.cfg"
+#rm -f --preserve-root "/boot/$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 $gbgmp/
@@ -491,13 +511,20 @@ mount -o subvolid=5 /dev/disk/by-uuid/$root_uuid $gbgmp/
 count_warning_menuentries=0
 # Count snapshots
 count_limit_snap=0
+# detect uuid requirement
+check_uuid_required
 # Detects if /boot is a separate partition
-if [[ "$root_uuid" != "$boot_uuid" ]]; then
-	printf "# Info: Separate boot partition detected \n" >&2 ;
+if [[ "$override_boot_partition_detection" == "true" ]]; then
+	printf "# Info: Override boot partition detection : enable \n" >&2 ;
 	boot_separate
 	else
-	printf "# Info: Separate boot partition not detected \n" >&2 ;
-	boot_bounded
+	if [[ "$root_uuid" != "$boot_uuid" ]]; then
+		printf "# Info: Separate boot partition detected \n" >&2 ;
+		boot_separate
+		else
+		printf "# Info: Separate boot partition not detected \n" >&2 ;
+		boot_bounded
+	fi
 fi
 # unmounting mount point
 umount $gbgmp
@@ -512,7 +539,7 @@ fi
 if [[ "${count_limit_snap}" = "0" || -z "${count_limit_snap}" ]]; then
 	print_error "No snapshots found."
 fi
-root_grub="$(make_system_path_relative_to_its_root /boot/grub)"
+root_grub="$(make_system_path_relative_to_its_root /boot/$grub_directory)"
 # Make a submenu in GRUB (grub.cfg)
 cat << EOF
 submenu '${submenuname}' {

41_snapshots-btrfs_config

@@ -14,3 +14,6 @@
 # GRUB_BTRFS_IGNORE_SPECIFIC_PATH=("var/lib/docker")                         # Ignore specific path during run "grub-mkconfig"
 # GRUB_BTRFS_SNAPPER_CONFIG="root"                                           # Snapper's config name to use
 # GRUB_BTRFS_DISABLE="false"                                                 # Disable Grub-btrfs
+# GRUB_BTRFS_DIRNAME=grub                                                    # Might be grub2 on some systems ex. /boot/grub2/...
+# 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                                          # Might be 'grub2-mkconfig' on some systems

README.md

@@ -86,6 +86,16 @@ Add this lines to /etc/default/grub:
 
 	(Disable grub-btrfs)
 
+* GRUB_BTRFS_DIRNAME="grub"
+
+	(Name of the grub folder on /boot/)
+
+* 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; this is 'grub2-mkconfig' on some systems)
 
 Generate grub.cfg (on Arch linux use grub-mkconfig -o /boot/grub/grub.cfg )
 
@@ -100,6 +110,8 @@ If you would like grub to automatically update when Snapper timeline snapshots a
 - `/etc/systemd/system/snapper-timeline.service.d/`
 - `/etc/systemd/system/snapper-cleanup.service.d/`
 
+Or copy `grub-btrfs.path` and `grub-btrfs.service` to `/etc/systemd/system/`
+
 Once the configuration files are in place, `systemctl daemon-reload` should be run to reload the units and make the changes active.
 
 ##

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/grub.d/41_snapshots-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'