sync-be

#!/bin/sh
#
# SPDX-License-Identifier: BSD-2-Clause
#
# Copyright (c) 2022 Klara Inc.
# Copyright (c) 2022 Rob Wing <rob.wing@klarasystems.com>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.

if [ -z "$1" -o -z "$2" ]; then
    echo "usage: $(basename $0) <new_bootenv> <bootenv_config>"
    exit 1
fi

BENAME=$1
BECONF=$2
OLDMP=
NEWMP=
UDATE=`date -u +%Y%m%d-%H%M`

[ "${BECONF#/}" = "${BECONF}" ] && \
    BECONF="$(pwd)/${BECONF}"

if [ ! -f "$BECONF" ]; then
    echo "error: $BECONF is not a file, exiting"
    exit 1
fi

echo "using config file: $BECONF"

sync() {
    _pwd=$(pwd)

    cd $OLDMP
    egrep -v '^#' $BECONF | while read glob; do

        # force relative paths from config file
        glob=${glob#/}
        find $glob -quit 2> /dev/null || continue

        for file in $glob; do
            # overwrite directory in the new boot environment
            if [ -d "$file" ] && [ -d $NEWMP/$file ]; then
                if ! rm -rf $NEWMP/$file; then
                    echo "error: unable to remove $NEWMP/$file, exiting.."
                    exit 1
                fi
            elif [ -f "$file" ]; then
                # make sure directory exists where file is being installed
                dir=$(dirname $NEWMP/$file)
                [ ! -d "$dir" ] && mkdir -p $dir
            fi

            echo "copying $file to $NEWMP/$file"
            if ! cp -vfa $file $NEWMP/$file; then
                echo "error: failed to copy, exiting!"
                exit 1
            fi
        done

    done;

    cd ${_pwd}
}

cleanup() {
    umount $NEWMP
    rmdir $NEWMP
}

# use the dataset that is being booted from
ROOTFS=`mount -p | awk '$2 == "/" && $3 == "zfs" { print $1 }'`
if [ -z "$ROOTFS" ]; then
    echo "error: zfs is not on root"
    exit 1
fi

# sanity check between booted root fs and bootfs
zpool="${ROOTFS%%/*}"
BOOTFS=`zpool get -H -o value bootfs ${zpool}| awk '$0 != "-" { print $0 }'`
if [ "$ROOTFS" != "$BOOTFS" ]; then
    echo "WARNING:  ZFS on rootfs doesn't match bootfs, continuing.."
    echo "          bootfs=$BOOTFS, rootfs=$ROOTFS"
fi


BEPATH="$(dirname $ROOTFS)/$BENAME"
if ! zfs recv -Fuv $BEPATH; then
    echo "error: zfs receive failed, exiting!"
    exit 1
fi

OLDMP="/"
NEWMP=`mktemp -d -t klara`
if [ $? -ne 0 ]; then
    echo "error: failed to create temporary mountpoint"
    exit 1
fi

if ! mount -t zfs $BEPATH $NEWMP; then
    echo "error: failed to mount $BEPATH at $NEWMP"
    exit 1
fi

if ! sync; then
    cleanup
fi

if ! zfs snapshot $BOOTFS@syncbe:$UDATE; then
    echo "error: failed to create $BOOTFS@syncbe:$UDATE snapshot"
    exit 1
fi

if ! zfs snapshot $BEPATH@syncbe:$UDATE; then
    echo "error: failed to create $BEPATH@syncbe:$UDATE snapshot"
    exit 1
fi

if ! zfsbootcfg "zfs:$BEPATH:"; then
    echo "error: setting $BEPATH for nextboot failed"
else
    echo "ready for reboot!"
fi

cleanup