ISO/archiso/initcpio/hooks/archiso

# args: source, newroot, mountpoint
_mnt_fs() {
    local img="${1}"
    local newroot="${2}"
    local mnt="${3}"
    local img_fullname="${img##*/}";
    local img_name="${img_fullname%%.*}"
    local dm_snap_name="${dm_snap_prefix}_${img_name}"
    local ro_dev ro_dev_size rw_dev

    ro_dev=$(losetup --find --show --read-only "${img}")
    echo ${ro_dev} >> /run/archiso/used_block_devices
    ro_dev_size=$(blockdev --getsz ${ro_dev})
    if [[ "${cowfile_size}" == "100" ]]; then
        rw_dev_size=${ro_dev_size}
    else
        # size calculation done in this way to avoid integer overflow when ro_dev_size is > 10.2G
        rw_dev_size=$((ro_dev_size/100*cowfile_size))
    fi

    if [[ "${cow_persistent}" == "P" ]]; then
        if [[ -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow" ]]; then
            msg ":: Found '/run/archiso/cowspace/${cow_directory}/${img_name}.cow', using as persistent."
        else
            msg ":: Creating '/run/archiso/cowspace/${cow_directory}/${img_name}.cow' as persistent."
            dd of="/run/archiso/cowspace/${cow_directory}/${img_name}.cow" count=0 seek=${rw_dev_size} &> /dev/null
        fi
    else
        if [[ -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow" ]]; then
            msg ":: Found '/run/archiso/cowspace/${cow_directory}/${img_name}.cow' but non-persistent requested, removing."
            rm -f "/run/archiso/cowspace/${cow_directory}/${img_name}.cow"
        fi
        msg ":: Creating '/run/archiso/cowspace/${cow_directory}/${img_name}.cow' as non-persistent."
        dd of="/run/archiso/cowspace/${cow_directory}/${img_name}.cow" count=0 seek=${rw_dev_size} &> /dev/null
    fi

    rw_dev=$(losetup --find --show "/run/archiso/cowspace/${cow_directory}/${img_name}.cow")
    echo ${rw_dev} >> /run/archiso/used_block_devices

    echo "0 ${ro_dev_size} snapshot ${ro_dev} ${rw_dev} ${cow_persistent} 8" | dmsetup create ${dm_snap_name}

    _mnt_dev "/dev/mapper/${dm_snap_name}" "${newroot}${mnt}" "-w"
    echo $(readlink -f /dev/mapper/${dm_snap_name}) >> /run/archiso/used_block_devices
}

# args: /path/to/image_file, mountpoint
_mnt_sfs() {
    local img="${1}"
    local mnt="${2}"
    local img_fullname="${img##*/}"
    local sfs_dev

    if [[ "${copytoram}" == "y" ]]; then
        msg -n ":: Copying squashfs image to RAM..."
        if ! cp "${img}" "/run/archiso/copytoram/${img_fullname}" ; then
            echo "ERROR: while copy '${img}' to '/run/archiso/copytoram/${img_fullname}'"
            launch_interactive_shell
        fi
        img="/run/archiso/copytoram/${img_fullname}"
        msg "done."
    fi
    sfs_dev=$(losetup --find --show --read-only "${img}")
    echo ${sfs_dev} >> /run/archiso/used_block_devices
    _mnt_dev "${sfs_dev}" "${mnt}" "-r"
}

# args: device, mountpoint, flags
_mnt_dev() {
    local dev="${1}"
    local mnt="${2}"
    local flg="${3}"

    mkdir -p "${mnt}"

    msg ":: Mounting '${dev}' to '${mnt}'"

    while ! poll_device "${dev}" 30; do
        echo "ERROR: '${dev}' device did not show up after 30 seconds..."
        echo "   Falling back to interactive prompt"
        echo "   You can try to fix the problem manually, log out when you are finished"
        launch_interactive_shell
    done

    if mount "${flg}" "${dev}" "${mnt}"; then
        msg ":: Device '${dev}' mounted successfully."
    else
        echo "ERROR; Failed to mount '${dev}'"
        echo "   Falling back to interactive prompt"
        echo "   You can try to fix the problem manually, log out when you are finished"
        launch_interactive_shell
    fi
}

_verify_checksum() {
    local _status
    cd "/run/archiso/bootmnt/${archisobasedir}"
    md5sum -c checksum.${arch}.md5 > /tmp/checksum.${arch}.log 2>&1
    _status=$?
    cd "${OLDPWD}"
    return ${_status}
}

run_hook() {
    arch="$(uname -m)"
    [[ -z "${cowspace_size}" ]] && cowspace_size="75%"
    [[ -z "${copytoram_size}" ]] && copytoram_size="75%"
    [[ -z "${archisobasedir}" ]] && archisobasedir="arch"
    [[ -z "${dm_snap_prefix}" ]] && dm_snap_prefix="arch"
    [[ -z "${archisodevice}" ]] && archisodevice="/dev/disk/by-label/${archisolabel}"
    if [[ -z "${cowfile_size}" ]]; then
        cowfile_size="100"
    else
        cowfile_size=${cowfile_size/%}
    fi

    if [[ -n "${cow_label}" ]]; then
        cow_device="/dev/disk/by-label/${cow_label}"
        [[ -z "${cow_persistent}" ]] && cow_persistent="P"
    elif [[ -n "${cow_device}" ]]; then
        [[ -z "${cow_persistent}" ]] && cow_persistent="P"
    else
        cow_persistent="N"
    fi

    [[ -z "${cow_directory}" ]] && cow_directory="persistent_${archisolabel}/${arch}"

    # set mount handler for archiso
    mount_handler="archiso_mount_handler"
}

# This function is called normally from init script, but it can be called
# as chain from other mount handlers.
# args: /path/to/newroot
archiso_mount_handler() {
    local newroot="${1}"

    if ! mountpoint -q "/run/archiso/bootmnt"; then
        _mnt_dev "${archisodevice}" "/run/archiso/bootmnt" "-r"
        if [[ "${copytoram}" != "y" ]]; then
            echo $(readlink -f ${archisodevice}) >> /run/archiso/used_block_devices
        fi
    fi

    if [[ "${checksum}" == "y" ]]; then
        if [[ -f "/run/archiso/bootmnt/${archisobasedir}/checksum.${arch}.md5" ]]; then
            msg -n ":: Self-test requested, please wait..."
            if _verify_checksum; then
                msg "done. Checksum is OK, continue booting."
            else
                echo "ERROR: one or more files are corrupted"
                echo "see /tmp/checksum.${arch}.log for details"
                launch_interactive_shell
            fi
        else
            echo "ERROR: checksum=y option specified but checksum.${arch}.md5 not found"
            launch_interactive_shell
        fi
    fi

    if [[ "${copytoram}" == "y" ]]; then
        msg ":: Mounting /run/archiso/copytoram (tmpfs) filesystem, size=${copytoram_size}"
        mkdir -p /run/archiso/copytoram
        mount -t tmpfs -o "size=${copytoram_size}",mode=0755 copytoram /run/archiso/copytoram
    fi

    if [[ -n "${cow_device}" ]]; then
        _mnt_dev "${cow_device}" "/run/archiso/cowspace" "-r"
        echo $(readlink -f ${cow_device}) >> /run/archiso/used_block_devices
        mount -o remount,rw "/run/archiso/cowspace"
    else
        msg ":: Mounting /run/archiso/cowspace (tmpfs) filesystem, size=${cowspace_size}..."
        mkdir -p /run/archiso/cowspace
        mount -t tmpfs -o "size=${cowspace_size}",mode=0755 cowspace /run/archiso/cowspace
    fi
    mkdir -p "/run/archiso/cowspace/${cow_directory}"

    _mnt_sfs "/run/archiso/bootmnt/${archisobasedir}/${arch}/airootfs.sfs" "/run/archiso/sfs/airootfs"
    _mnt_fs "/run/archiso/sfs/airootfs/airootfs.img" "${newroot}" "/"

    if [[ "${copytoram}" == "y" ]]; then
        umount /run/archiso/bootmnt
    fi
}

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