meta-security/recipes-core/initrdscripts/initramfs-framework-dm/dmverity

#!/bin/sh

dmverity_enabled() {
    return 0
}

dmverity_run() {
    DATA_SIZE="__not_set__"
    DATA_BLOCK_SIZE="__not_set__"
    ROOT_HASH="__not_set__"

    . /usr/share/misc/dm-verity.env

    C=0
    delay=${bootparam_rootdelay:-1}
    timeout=${bootparam_roottimeout:-5}
    RDEV="$(realpath /dev/disk/by-partuuid/${bootparam_root#PARTUUID=})"
    while [ ! -b "${RDEV}" ]; do
        if [ $(( $C * $delay )) -gt $timeout ]; then
            fatal "Root device resolution failed"
            exit 1
        fi

        case "${bootparam_root}" in
            ID=*)
                RDEV="$(realpath /dev/disk/by-id/${bootparam_root#ID=})"
                ;;
            LABEL=*)
                RDEV="$(realpath /dev/disk/by-label/${bootparam_root#LABEL=})"
                ;;
            PARTLABEL=*)
                RDEV="$(realpath /dev/disk/by-partlabel/${bootparam_root#PARTLABEL=})"
                ;;
            PARTUUID=*)
                RDEV="$(realpath /dev/disk/by-partuuid/${bootparam_root#PARTUUID=})"
                ;;
            PATH=*)
                RDEV="$(realpath /dev/disk/by-path/${bootparam_root#PATH=})"
                ;;
            UUID=*)
                RDEV="$(realpath /dev/disk/by-uuid/${bootparam_root#UUID=})"
                ;;
            *)
                RDEV="${bootparam_root}"
        esac
        debug "Sleeping for $delay second(s) to wait root to settle..."
        sleep $delay
        C=$(( $C + 1 ))

    done

    veritysetup \
        --data-block-size=${DATA_BLOCK_SIZE} \
        --hash-offset=${DATA_SIZE} \
        create rootfs \
        ${RDEV} \
        ${RDEV} \
        ${ROOT_HASH}

    mount \
        -o ro \
        /dev/mapper/rootfs \
        ${ROOTFS_DIR} || exit 2
}