path: root/builder/modules.d/dnbd3-rootfs/hooks/prepare-root-partition.sh

#!/usr/bin/env bash
# region imports
source '/usr/lib/rebash/core.sh'
core.import '/usr/lib/openslx/tools.sh'
core.import exceptions
core.import utils
core.import logging
type emergency_shell >/dev/null 2>&1 || source /lib/dracut-lib.sh
# endregion
exceptions.try
{
source /etc/openslx
logging.set_commands_level debug
logging.set_level debug
[[ "$SLX_LOG_FILE_PATH" == "" ]] && SLX_LOG_FILE_PATH=/var/log/openslx
logging.set_log_file "$SLX_LOG_FILE_PATH"

# region find writable partition
# support comma-separated list of identifiers
IFS_backup="$IFS"
IFS=','
for identifier in $SLX_WRITABLE_DEVICE_IDENTIFIER; do
  if [[ "$identifier" != '' ]] &&
    persistent_device="$(
      tools.find_block_device "$identifier" '' \
        "$SLX_WRITABLE_DEVICE_IDENTIFIER_TIMEOUT_IN_SECONDS")"; then
    break
  fi
  persistent_device=
done
IFS="$IFS_backup"

if [ -z "$persistent_device" ]; then
    logging.warn "Failed to find unique device with identifiers" \
        "\"${SLX_WRITABLE_DEVICE_IDENTIFIER}\"; matched devices:" \
        "\"${persistent_device}\""
fi

if [ -n "$SLX_WRITABLE_DEVICE_STORAGE_FILE_PATH" ] && [ -n "$persistent_device" ]; then
    persistent_mountpoint=/mnt/slx_writable_device
    storage_file_path="${persistent_mountpoint}/$SLX_WRITABLE_DEVICE_STORAGE_FILE_PATH"
    ! mkdir --parents "$(dirname "$storage_file_path")"
    if ! mount --type auto "$persistent_device" "$persistent_mountpoint"; then
        logging.warn "Failed to mount $persistent_device, checking filesystem."
        ! $SLX_WRITABLE_DEVICE_STORAGE_FILESYSTEM_CHECK_COMMAND \
            "$persistent_device"
        if ! mount --type auto "$persistent_device" "$persistent_mountpoint"; then
            logging.warn "Mounting $persistent_device, still failing," \
                "creating new filesystem on device"
            $SLX_WRITABLE_DEVICE_STORAGE_FILESYSTEM_CREATE_COMMAND \
                "$persistent_device"
        fi
        if ! mount --type auto "$persistent_device" "$persistent_mountpoint"; then
            logging.warn "Mounting $persistent_device, still failing," \
                "giving up, and using ramdisk"
            persistent_device=""
        fi
    fi
    if [ -n "$persistent_device" ]; then
        if [ ! -e "$storage_file_path" ]; then
            # Create a sparse file.
            dd of="$storage_file_path" bs=1M \
                seek="$SLX_WRITABLE_DEVICE_STORAGE_MAXIMUM_FILE_SIZE_IN_MB" count=0
        fi
        persistent_device="$(losetup --find)"
        losetup "$persistent_device" "$storage_file_path"
    fi
fi

# "P" for persistent storage, "N" for not persistent (affects dmsetup call,
# see scripts/device-add-write-layer.sh)
persistent='N'
if [ -n "$persistent_device" ]; then
    writable_device="$persistent_device"
    if [ "$SLX_WRITABLE_DEVICE_PERSISTENT" = "yes" ]; then
        persistent='P'
    fi
else
    ramdisk_size_in_kb="$SLX_RAMDISK_SIZE_IN_KB"
    if [ "$ramdisk_size_in_kb" = '' ]; then
        ramdisk_size_in_kb="$(awk '/MemTotal/ {print $2}' /proc/meminfo)"
    fi
    # NOTE: If the kernel modul "brd" is compiled into current kernel we can't
    # configure ram disk size dynamically. In this case it have to be
    # configured via kernel command line: "brd.rd_size=SITE_IN_KILOBYTE"
    # statically:
    #! rmmod brd 2>/dev/null
    #modprobe brd max_part=1 rd_size="$ramdisk_size_in_kb"
    #writable_device='/dev/ram0'
    ramdisk_location="$(mktemp)"
    dd of="$ramdisk_location" seek="$ramdisk_size_in_kb" count=0 1>/dev/null
    writable_device="$(losetup --find)"
    losetup "$writable_device" "$ramdisk_location"
fi
# endregion
# region connect dnbd3
IFS_backup="$IFS"
IFS=","
return_code=1
for host in ${SLX_DNBD3_SERVERS}; do
    logging.info "Trying host \"$host\"."
    if systemd-preserve-process-marker dnbd3-client --host "$host" --image \
        "${SLX_DNBD3_IMAGE}" --device "$SLX_DNBD3_DEVICE" \
        --rid "$SLX_DNBD3_RID"; then
        return_code=0
        break
    fi
done
IFS="$IFS_backup"

if [[ $return_code != 0 ]]; then
    logging.warn "Failed to connect \"${SLX_DNBD3_IMAGE}\" (revision" \
        "\"$SLX_DNBD3_RID\") from one of \"$SLX_DNBD3_SERVERS\" to" \
        "\"$SLX_DNBD3_DEVICE\"."
    exit 1
fi
# endregion
# region scan partitions
if [ "$SLX_LOG_FILE_PATH" != "" ]; then
    read_only_device="$(container-unpack-xmount "$SLX_DNBD3_DEVICE" \
        2>>"$SLX_LOG_FILE_PATH")"
else
    read_only_device="$(container-unpack-xmount "$SLX_DNBD3_DEVICE")"
fi


# Fail fast if no device could be determined.
[ -z "$read_only_device" ] && exit 1
# endregion
# region find read-only partition
if [ -z "$SLX_SYSTEM_PARTITION_PREPARATION_SCRIPT" ]; then
    if [ -z "$SLX_SYSTEM_PARTITION_IDENTIFIER" ]; then
        # if empty use whole device
        read_only_partition="$read_only_device"
        true
    else
        read_only_partition="$(tools.find_block_device \
            "$SLX_SYSTEM_PARTITION_IDENTIFIER" "$read_only_device")"
    fi
else
    eval "$SLX_SYSTEM_PARTITION_PREPARATION_SCRIPT"
fi
if [[ ! $? || -z "$read_only_partition" ]]; then
    logging.error "Failed to find unique device with identifier" \
        "\"${SLX_SYSTEM_PARTITION_IDENTIFIER}\"; matched devices:" \
        "\"${read_only_partition}\""
    exit 1
fi
# endregion

logging.info "Using read-only partition: $read_only_partition"
logging.info "Using writable device $writable_device, persistency: $persistent"

# combine devices with device mapper
device-add-write-layer "root" "$read_only_partition" "$writable_device" \
    "$persistent"

}
exceptions.catch
{
    logging.error "$exceptions_last_traceback"
    emergency_shell "error in ${BASH_SOURCE[0]}"
}
# region vim modline

# vim: set tabstop=4 shiftwidth=4 expandtab:
# vim: foldmethod=marker foldmarker=region,endregion:

# endregion