[2/2] grub-btrfs: New package

  This kind of grub addon will extend the grub boot menu by a additional
submenu where a BTRFS snapshot can be selected to directly use as root
volume and boot into it.

The grub-btrfsd daemon is using inotify(tools) to watch the snapshot directory for
new or deleted snapshots and calls grub-mkconfig to adjust the snapshot grub submenu

Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
---
 config/rootfiles/common/grub-btrfs         | 14 ++++
 config/rootfiles/common/x86_64/initscripts |  4 ++
 lfs/grub-btrfs                             | 79 ++++++++++++++++++++++
 lfs/initscripts                            |  3 +
 make.sh                                    |  1 +
 src/initscripts/system/grub-btrfsd         | 61 +++++++++++++++++
 6 files changed, 162 insertions(+)
 create mode 100644 config/rootfiles/common/grub-btrfs
 create mode 100644 lfs/grub-btrfs
 create mode 100644 src/initscripts/system/grub-btrfsd
  

Hello,

> On 24 Mar 2024, at 12:39, Stefan Schantl <stefan.schantl@ipfire.org> wrote:
> 
> This kind of grub addon will extend the grub boot menu by a additional
> submenu where a BTRFS snapshot can be selected to directly use as root
> volume and boot into it.
> 
> The grub-btrfsd daemon is using inotify(tools) to watch the snapshot directory for
> new or deleted snapshots and calls grub-mkconfig to adjust the snapshot grub submenu
> 
> Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>
> ---
> config/rootfiles/common/grub-btrfs         | 14 ++++
> config/rootfiles/common/x86_64/initscripts |  4 ++
> lfs/grub-btrfs                             | 79 ++++++++++++++++++++++
> lfs/initscripts                            |  3 +
> make.sh                                    |  1 +
> src/initscripts/system/grub-btrfsd         | 61 +++++++++++++++++
> 6 files changed, 162 insertions(+)
> create mode 100644 config/rootfiles/common/grub-btrfs
> create mode 100644 lfs/grub-btrfs
> create mode 100644 src/initscripts/system/grub-btrfsd
> 
> diff --git a/config/rootfiles/common/grub-btrfs b/config/rootfiles/common/grub-btrfs
> new file mode 100644
> index 000000000..a612af065
> --- /dev/null
> +++ b/config/rootfiles/common/grub-btrfs
> @@ -0,0 +1,14 @@
> +boot/grub/grubenv
> +etc/default/grub-btrfs
> +etc/default/grub-btrfs/config
> +etc/grub.d/41_snapshots-btrfs
> +usr/bin/grub-btrfsd
> +#usr/lib/systemd/system/grub-btrfsd.service
> +#usr/share/doc/grub-btrfs
> +#usr/share/doc/grub-btrfs/README.md
> +#usr/share/doc/grub-btrfs/initramfs-overlayfs.md
> +#usr/share/licenses
> +#usr/share/licenses/grub-btrfs
> +#usr/share/licenses/grub-btrfs/LICENSE
> +#usr/share/man/man8/grub-btrfs.8.bz2
> +#usr/share/man/man8/grub-btrfsd.8.bz2
> diff --git a/config/rootfiles/common/x86_64/initscripts b/config/rootfiles/common/x86_64/initscripts
> index a5e1596fb..2d6fa85dc 100644
> --- a/config/rootfiles/common/x86_64/initscripts
> +++ b/config/rootfiles/common/x86_64/initscripts
> @@ -26,6 +26,7 @@ etc/rc.d/init.d/firewall
> etc/rc.d/init.d/firstsetup
> etc/rc.d/init.d/fsresize
> etc/rc.d/init.d/functions
> +etc/rc.d/init.d/grub-btrfsd
> etc/rc.d/init.d/halt
> etc/rc.d/init.d/ipsec
> etc/rc.d/init.d/leds
> @@ -92,6 +93,7 @@ etc/rc.d/init.d/vnstat
> etc/rc.d/init.d/waitdrives
> etc/rc.d/init.d/wlanclient
> #etc/rc.d/rc0.d
> +etc/rc.d/rc0.d/K01grub-btrfsd
> #etc/rc.d/rc0.d/K01imspetor
> #etc/rc.d/rc0.d/K01motion
> #etc/rc.d/rc0.d/K01vdradmin
> @@ -135,10 +137,12 @@ etc/rc.d/rc3.d/S32apache
> etc/rc.d/rc3.d/S40fcron
> etc/rc.d/rc3.d/S98rc.local
> #etc/rc.d/rc3.d/S98sslh
> +etc/rc.d/rc3.d/S99grub-btrfsd
> #etc/rc.d/rc3.d/S99imspetor
> #etc/rc.d/rc3.d/S99motion
> #etc/rc.d/rc3.d/S99vdradmin
> #etc/rc.d/rc6.d
> +etc/rc.d/rc6.d/K01grub-btrfsd
> #etc/rc.d/rc6.d/K01imspetor
> #etc/rc.d/rc6.d/K01motion
> #etc/rc.d/rc6.d/K01vdradmin
> diff --git a/lfs/grub-btrfs b/lfs/grub-btrfs
> new file mode 100644
> index 000000000..8dc0c4f3e
> --- /dev/null
> +++ b/lfs/grub-btrfs
> @@ -0,0 +1,79 @@
> +###############################################################################
> +#                                                                             #
> +# IPFire.org - A linux based firewall                                         #
> +# Copyright (C) 2007-2023  IPFire Team  <info@ipfire.org>                     #
> +#                                                                             #
> +# This program is free software: you can redistribute it and/or modify        #
> +# it under the terms of the GNU General Public License as published by        #
> +# the Free Software Foundation, either version 3 of the License, or           #
> +# (at your option) any later version.                                         #
> +#                                                                             #
> +# This program is distributed in the hope that it will be useful,             #
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
> +# GNU General Public License for more details.                                #
> +#                                                                             #
> +# You should have received a copy of the GNU General Public License           #
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
> +#                                                                             #
> +###############################################################################
> +
> +###############################################################################
> +# Definitions
> +###############################################################################
> +
> +include Config
> +
> +VER        = 4.13
> +
> +THISAPP    = grub-btrfs-$(VER)
> +DL_FILE    = $(THISAPP).tar.gz
> +DL_FROM    = $(URL_IPFIRE)
> +DIR_APP    = $(DIR_SRC)/$(THISAPP)
> +TARGET     = $(DIR_INFO)/$(THISAPP)
> +
> +###############################################################################
> +# Top-level Rules
> +###############################################################################
> +
> +objects = $(DL_FILE)
> +
> +$(DL_FILE) = $(DL_FROM)/$(DL_FILE)
> +
> +$(DL_FILE)_BLAKE2 = e2f11a0a8282e3ec8ff8223e3bad70b5d5c5e81b4d740a1bf3554db412dbe48a8a0f216f4e6c65ae1d11c01a27b8b92bae9b470c60d2389505ce089511536e1a
> +
> +install : $(TARGET)
> +
> +check : $(patsubst %,$(DIR_CHK)/%,$(objects))
> +
> +download :$(patsubst %,$(DIR_DL)/%,$(objects))
> +
> +b2 : $(subst %,%_BLAKE2,$(objects))
> +
> +dist:
> + @$(PAK)
> +
> +###############################################################################
> +# Downloading, checking, b2sum
> +###############################################################################
> +
> +$(patsubst %,$(DIR_CHK)/%,$(objects)) :
> + @$(CHECK)
> +
> +$(patsubst %,$(DIR_DL)/%,$(objects)) :
> + @$(LOAD)
> +
> +$(subst %,%_BLAKE2,$(objects)) :
> + @$(B2SUM)
> +
> +###############################################################################
> +# Installation Details
> +###############################################################################
> +
> +$(TARGET) : $(patsubst %,$(DIR_DL)/%,$(objects))
> + @$(PREBUILD)
> + @rm -rf $(DIR_APP) && cd $(DIR_SRC) && tar axf $(DIR_DL)/$(DL_FILE)
> + $(UPDATE_AUTOMAKE)
> + cd $(DIR_APP) && make install
> + @rm -rf $(DIR_APP)
> + @$(POSTBUILD)
> diff --git a/lfs/initscripts b/lfs/initscripts
> index e078632ab..4d67ee0c4 100644
> --- a/lfs/initscripts
> +++ b/lfs/initscripts
> @@ -91,6 +91,7 @@ $(TARGET) :
> install -v -m 755 $$i /etc/rc.d/helper/; \
> done
> 
> + ln -sf ../init.d/grub-btrfsd /etc/rc.d/rc0.d/K01grub-btrfsd
> ln -sf ../init.d/imspetor /etc/rc.d/rc0.d/K01imspetor
> ln -sf ../init.d/motion /etc/rc.d/rc0.d/K01motion
> ln -sf ../init.d/vdradmin /etc/rc.d/rc0.d/K01vdradmin
> @@ -132,10 +133,12 @@ $(TARGET) :
> ln -sf ../init.d/fcron /etc/rc.d/rc3.d/S40fcron
> ln -sf ../../sysconfig/rc.local /etc/rc.d/rc3.d/S98rc.local
> ln -sf ../init.d/sslh /etc/rc.d/rc3.d/S98sslh
> + ln -sf ../init.d/grub-btrfsd /etc/rc.d/rc3.d/S99grub-btrfsd
> ln -sf ../init.d/imspetor /etc/rc.d/rc3.d/S99imspetor
> ln -sf ../init.d/motion /etc/rc.d/rc3.d/S99motion
> ln -sf ../init.d/vdradmin /etc/rc.d/rc3.d/S99vdradmin
> 
> + ln -sf ../init.d/grub-btrfsd /etc/rc.d/rc6.d/K01grub-btrfsd
> ln -sf ../init.d/imspetor /etc/rc.d/rc6.d/K01imspetor
> ln -sf ../init.d/motion /etc/rc.d/rc6.d/K01motion
> ln -sf ../init.d/vdradmin /etc/rc.d/rc6.d/K01vdradmin
> diff --git a/make.sh b/make.sh
> index 1834b927a..adc03f4e6 100755
> --- a/make.sh
> +++ b/make.sh
> @@ -1714,6 +1714,7 @@ buildipfire() {
>   lfsmake2 wsdd
>   lfsmake2 btrfs-progs
>   lfsmake2 inotify-tools
> +  lfsmake2 grub-btrfs
> 
>   # Kernelbuild ... current we have no platform that need
>   # multi kernel builds so KCFG is empty
> diff --git a/src/initscripts/system/grub-btrfsd b/src/initscripts/system/grub-btrfsd
> new file mode 100644
> index 000000000..dc5e32ad4
> --- /dev/null
> +++ b/src/initscripts/system/grub-btrfsd
> @@ -0,0 +1,61 @@
> +#!/bin/sh
> +###############################################################################
> +#                                                                             #
> +# IPFire.org - A linux based firewall                                         #
> +# Copyright (C) 2007-2024  IPFire Team  <info@ipfire.org>                     #
> +#                                                                             #
> +# This program is free software: you can redistribute it and/or modify        #
> +# it under the terms of the GNU General Public License as published by        #
> +# the Free Software Foundation, either version 3 of the License, or           #
> +# (at your option) any later version.                                         #
> +#                                                                             #
> +# This program is distributed in the hope that it will be useful,             #
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
> +# GNU General Public License for more details.                                #
> +#                                                                             #
> +# You should have received a copy of the GNU General Public License           #
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
> +#                                                                             #
> +###############################################################################
> +
> +. /etc/sysconfig/rc
> +. ${rc_functions}
> +
> +SNAPSHOTDIR="/.snapshots"
> +PIDFILE="/run/grub-btrfsd.pid"
> +
> +root_is_btrfs() {
> +    [ "$(stat -f --format="%T" /)" == "btrfs" ] || return 1
> +
> +    return 0
> +}

I think we should have this function available in the “functions” file as I can see other things needing this, too.

Recently I have been touching a lot of code that had the same functionality implemented several times (at least two, sometimes even three or four times) which causes many problems. So I would like to be more strict in what we accept in the code so that things don’t become even messier than they are now. Not that this function here is the biggest problem, but I have been put in a really bad mood about a lot of OpenVPN and web UI code…

I think we can even solve this a lot smarter. Can we have the function simply return the filesystem type of the root filesystem? You can then write code like this:

case “$(root_fs_type)” in
  btrfs)
    …
    ;;
esac

If there is any necessity to deal with other filesystem the case could match something else, too without introducing another function for another filesystem.

I think this could already become handy when deprecating reiserfs.

This would become absolute gold if you would accept the mountpoint so that we can even check for other filesystems as they might use reiferfs, too.

Best,
-Michael

> +
> +case "$1" in
> +        start)
> + root_is_btrfs || exit 0
> +
> + boot_mesg "Starting Grub/Btrfs snapshot manager..."
> + loadproc -b -p "$PIDFILE" /usr/bin/grub-btrfsd --syslog "$SNAPSHOTDIR"
> +
> + # Store the gained PID to the defined pidfile
> + echo "$!" > "$PIDFILE"

loadproc should do this automatically already. If not, then something is broken.

It is also enough to define PIDFILE globally as loadproc/killproc etc. will automatically use it.

> + ;;
> +
> + stop)
> + boot_mesg "Stopping grub-btrfsd..."
> + killproc -p "$PIDFILE" /usr/bin/grub-btrfsd
> + sleep 1;
> + ;;
> +
> + restart)
> + $0 stop
> + sleep 2
> + $0 start
> + ;;
> +
> + *)
> + echo "Usage: $0 {start|stop|restart}"
> + exit 1
> + ;;
> +esac
> -- 
> 2.39.2
>