xref: /external/autotest/client/cros/faft/rpc_functions.py

# Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Code to provide functions for FAFT tests.

These will be exposed via an xmlrpc server running on the DUT.

@note: When adding categories, please also update server/cros/faft/rpc_proxy.pyi
"""

from __future__ import print_function

import binascii
import httplib
import logging
import os
import signal
import six
import sys
import tempfile
import traceback
import xmlrpclib

from autotest_lib.client.common_lib import lsbrelease_utils
from autotest_lib.client.common_lib.cros import cros_config
from autotest_lib.client.cros import xmlrpc_server
from autotest_lib.client.cros.faft.utils import (
        cgpt_handler,
        os_interface,
        firmware_check_keys,
        firmware_updater,
        flashrom_handler,
        kernel_handler,
        rootfs_handler,
        tpm_handler,
)


class FaftXmlRpcDelegate(xmlrpc_server.XmlRpcDelegate):
    """
    A class which routes RPC methods to the proper servicers.

    Firmware tests are able to call an RPC method via:
        <FAFTClient>.[category].[method_name](params)
    When XML-RPC is being used, the RPC server routes the called method to:
        <XmlRpcDelegate>._dispatch('[category].[method_name]', params)
    The method is then dispatched to a Servicer class.
    """

    def __init__(self, os_if):
        """Initialize the servicer for each category.

        @type os_if: os_interface.OSInterface
        """
        self._ready = False
        self.bios = BiosServicer(os_if)
        self.cgpt = CgptServicer(os_if)
        self.ec = EcServicer(os_if)
        self.kernel = KernelServicer(os_if)
        self.rootfs = RootfsServicer(os_if)
        self.rpc_settings = RpcSettingsServicer(os_if)
        self.system = SystemServicer(os_if)
        self.tpm = TpmServicer(os_if)
        self.updater = UpdaterServicer(os_if)

        self._rpc_servicers = {
                'bios': self.bios,
                'cgpt': self.cgpt,
                'ec': self.ec,
                'kernel': self.kernel,
                'rpc_settings': self.rpc_settings,
                'rootfs': self.rootfs,
                'system': self.system,
                'tpm': self.tpm,
                'updater': self.updater
        }

        self._os_if = os_if

    def __enter__(self):
        """Enter the the delegate context (when XmlRpcServer.run() starts).

        The server is marked ready here, rather than immediately when created.
        """
        logging.debug("%s: Serving FAFT functions", self.__class__.__name__)
        self._ready = True
        self._os_if.start_file_logging()

    def __exit__(self, exception, value, traceback):
        """Exit the delegate context (when XmlRpcServer.run() finishes).

        The server is marked not ready, to prevent the client from using
        the wrong server when quitting one instance and starting another.
        """
        self._ready = False
        self._os_if.stop_file_logging()
        logging.debug("%s: Done.", self.__class__.__name__)

    def quit(self):
        """Exit the xmlrpc server."""
        self._ready = False
        os.kill(os.getpid(), signal.SIGINT)

    def ready(self):
        """Is the RPC server ready to serve calls in a useful manner?

        The server is only marked ready during the XmlRpcServer.run() loop.
        This method suppresses the extra logging of ready() from the superclass.
        """
        return self._ready

    def _report_error(self, fault_code, message, exc_info=False):
        """Raise the given RPC error text, including information about last
        exception from sys.exc_info().  The log file gets the traceback in text;
        the raised exception keeps the old traceback (but not in text).

        Note: this must be called right after the original exception, or it may
        report the wrong exception.

        @raise: xmlrpclib.Fault

        @param fault_code: the status code to use
        @param message: the string message to include before exception text
        @param exc_info: true to use the tuple from sys.exc_info()
        @return the exception to raise

        @type fault_code: int
        @type message: str
        @type exc_info: bool
        @rtype: Exception
        """
        if exc_info:
            tb = None
            try:
                (exc_class, exc, tb) = sys.exc_info()

                tb_str = ''.join(
                        traceback.format_exception(exc_class, exc, tb))
                self._os_if.log('Error: %s.\n%s' % (message, tb_str.rstrip()))

                if not isinstance(exc, xmlrpclib.Fault):
                    exc_str = ''.join(
                            traceback.format_exception_only(exc_class, exc))
                    exc = xmlrpclib.Fault(
                            fault_code, '%s. %s' % (message, exc_str.rstrip()))
                six.reraise(exc, None, tb)
            finally:
                del exc_info
                del tb
        else:
            self._os_if.log('Error: %s' % message)
            return xmlrpclib.Fault(fault_code, message)

    def _dispatch(self, called_method, params):
        """
        Send any RPC call to the appropriate servicer method.

        @param called_method: The method of FAFTClient that was called.
                              Should take the form 'category.method'.
        @param params: The arguments passed into the method.

        @type called_method: str
        @type params: tuple

        @raise: xmlrpclib.Fault (using http error codes for fault codes)
        """
        self._os_if.log('Called: %s%s' % (called_method, params))

        name_pieces = called_method.split('.')

        if not name_pieces:
            raise self._report_error(
                    httplib.BAD_REQUEST,
                    'RPC request is invalid (completely empty): "%s"' %
                    called_method)

        method_name = name_pieces.pop()
        category = '.'.join(name_pieces)

        if (method_name.startswith('_')
                and method_name not in ('__str__', '__repr__', '__call__')):
            # *._private() or *.__special__()
            # Forbid early, to prevent seeing which methods exist.
            raise self._report_error(
                    httplib.FORBIDDEN,
                    'RPC method name is private: %s%s[%s]' %
                    (category, '.' if category else '', method_name))

        elif not method_name:
            # anything.()
            raise self._report_error(
                    httplib.BAD_REQUEST,
                    'RPC method name is empty: %s%s[%s]' %
                    (category, '.' if category else '', method_name))

        if category in self._rpc_servicers:
            # system.func()
            holder = self._rpc_servicers[category]
            if not hasattr(holder, method_name):
                raise self._report_error(
                        httplib.NOT_FOUND,
                        'RPC method not found: %s.[%s]' %
                        (category, method_name))

        elif category:
            # invalid.func()
            raise self._report_error(
                    httplib.NOT_FOUND,
                    'RPC category not found: [%s].%s' %
                    (category, method_name))

        else:
            # .func() or .invalid()
            holder = self
            if not hasattr(holder, method_name):
                raise self._report_error(
                        httplib.NOT_FOUND,
                        'RPC method not found: [%s]' % method_name)

        try:
            method = getattr(holder, method_name)

        except AttributeError:
            raise self._report_error(
                    httplib.NOT_IMPLEMENTED,
                    'RPC method not found: "%s"' % called_method, exc_info=True)

        try:
            return method(*params)

        except Exception:
            raise self._report_error(
                    httplib.INTERNAL_SERVER_ERROR,
                    'RPC call failed: %s()' % called_method, exc_info=True)


class BiosServicer(object):
    """Class to service all BIOS RPCs"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if

        # This attribute is accessed via a property, so it can load lazily
        # when actually used by the test.
        self._real_bios_handler = flashrom_handler.FlashromHandler(
                self._os_if, None, '/usr/share/vboot/devkeys', 'bios')

    @property
    def _bios_handler(self):
        """Return the BIOS flashrom handler, after initializing it if necessary

        @rtype: flashrom_handler.FlashromHandler
        """
        if not self._real_bios_handler.initialized:
            self._real_bios_handler.init()
        return self._real_bios_handler

    def reload(self):
        """Reload the firmware image that may be changed."""
        self._bios_handler.new_image()

    def get_gbb_flags(self):
        """Get the GBB flags.

        @return: An integer of the GBB flags.
        """
        return self._bios_handler.get_gbb_flags()

    def set_gbb_flags(self, flags):
        """Set the GBB flags.

        @param flags: An integer of the GBB flags.
        """
        self._bios_handler.set_gbb_flags(flags, write_through=True)

    def get_preamble_flags(self, section):
        """Get the preamble flags of a firmware section.

        @param section: A firmware section, either 'a' or 'b'.
        @return: An integer of the preamble flags.
        """
        return self._bios_handler.get_section_flags(section)

    def set_preamble_flags(self, section, flags):
        """Set the preamble flags of a firmware section.

        @param section: A firmware section, either 'a' or 'b'.
        @param flags: An integer of preamble flags.
        """
        version = self.get_version(section)
        self._bios_handler.set_section_version(
                section, version, flags, write_through=True)

    def get_body_sha(self, section):
        """Get SHA1 hash of BIOS RW firmware section.

        @param section: A firmware section, either 'a' or 'b'.
        @return: A string of the body SHA1 hash.
        """
        return self._bios_handler.get_section_sha(section)

    def get_sig_sha(self, section):
        """Get SHA1 hash of firmware vblock in section.

        @param section: A firmware section, either 'a' or 'b'.
        @return: A string of the sig SHA1 hash.
        """
        return self._bios_handler.get_section_sig_sha(section)

    def get_section_fwid(self, section=None):
        """Retrieve the RO or RW fwid.

        @param section: A firmware section, either 'a' or 'b'.
        @return: A string of the fwid
        """
        return self._bios_handler.get_section_fwid(section)

    def corrupt_sig(self, section):
        """Corrupt the requested firmware section signature.

        @param section: A firmware section, either 'a' or 'b'.
        """
        self._bios_handler.corrupt_firmware(section)

    def restore_sig(self, section):
        """Restore the previously corrupted firmware section signature.

        @param section: A firmware section, either 'a' or 'b'.
        """
        self._bios_handler.restore_firmware(section)

    def corrupt_body(self, section, corrupt_all=False):
        """Corrupt the requested firmware section body.

        @param section: A firmware section, either 'a' or 'b'.
        @param corrupt_all (optional): Corrupt all bytes of the fw section,
                                       rather than just one byte.
        """
        self._bios_handler.corrupt_firmware_body(section, corrupt_all)

    def restore_body(self, section):
        """Restore the previously corrupted firmware section body.

        @param section: A firmware section, either 'a' or 'b'.
        """
        self._bios_handler.restore_firmware_body(section)

    def _modify_version(self, section, delta):
        """Modify firmware version for the requested section, by adding delta.

        The passed in delta, a positive or a negative number, is added to the
        original firmware version.
        """
        original_version = self.get_version(section)
        new_version = original_version + delta
        flags = self._bios_handler.get_section_flags(section)
        self._os_if.log('Setting firmware section %s version from %d to %d' %
                        (section, original_version, new_version))
        self._bios_handler.set_section_version(
                section, new_version, flags, write_through=True)

    def move_version_backward(self, section):
        """Decrement firmware version for the requested section."""
        self._modify_version(section, -1)

    def move_version_forward(self, section):
        """Increase firmware version for the requested section."""
        self._modify_version(section, 1)

    def get_version(self, section):
        """Retrieve firmware version of a section."""
        return self._bios_handler.get_section_version(section)

    def get_datakey_version(self, section):
        """Return firmware data key version."""
        return self._bios_handler.get_section_datakey_version(section)

    def get_kernel_subkey_version(self, section):
        """Return kernel subkey version."""
        return self._bios_handler.get_section_kernel_subkey_version(section)

    def dump_whole(self, bios_path):
        """Dump the current BIOS firmware to a file, specified by bios_path.

        @param bios_path: The path of the BIOS image to be written.
        """
        self._bios_handler.dump_whole(bios_path)

    def write_whole(self, bios_path):
        """Write the firmware from bios_path to the current system.

        @param bios_path: The path of the source BIOS image
        """
        self._bios_handler.new_image(bios_path)
        self._bios_handler.write_whole()

    def strip_modified_fwids(self):
        """Strip trailing suffixes out of the FWIDs (see modify_image_fwids).

        @return: a dict of any fwids that were adjusted, by section (ro, a, b)
        @rtype: dict
        """
        return self._bios_handler.strip_modified_fwids()

    def set_write_protect_region(self, region, enabled=None):
        """Modify software write protect region and flag in one operation.

        @param region: Region to set (usually WP_RO)
        @param enabled: If True, run --wp-enable; if False, run --wp-disable.
                        If None (default), don't specify either one.
        """
        self._bios_handler.set_write_protect_region(region, enabled)

    def set_write_protect_range(self, start, length, enabled=None):
        """Modify software write protect range and flag in one operation.

        @param start: offset (bytes) from start of flash to start of range
        @param length: offset (bytes) from start of range to end of range
        @param enabled: If True, run --wp-enable; if False, run --wp-disable.
                        If None (default), don't specify either one.
        """
        self._bios_handler.set_write_protect_range(start, length, enabled)

    def get_write_protect_status(self):
        """Get a dict describing the status of the write protection

        @return: {'enabled': True/False, 'start': '0x0', 'length': '0x0', ...}
        @rtype: dict
        """
        return self._bios_handler.get_write_protect_status()

    def is_available(self):
        """Return True if available, False if not."""
        # Use the real handler, to avoid .init() raising an exception
        return self._real_bios_handler.is_available()

    def get_write_cmd(self, image=None):
        """Get the command needed to write the whole image to the device.

        @param image: the filename (empty to use current handler data)
        """
        if image:
            # Don't bother loading the usual image, since it's overridden.
            return self._real_bios_handler.get_write_cmd(image)
        else:
            return self._bios_handler.get_write_cmd()

class CgptServicer(object):
    """Class to service all CGPT RPCs"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if
        self._cgpt_handler = cgpt_handler.CgptHandler(self._os_if)

    def get_attributes(self):
        """Get kernel attributes."""
        rootdev = self._os_if.get_root_dev()
        self._cgpt_handler.read_device_info(rootdev)
        return {
                'A': self._cgpt_handler.get_partition(rootdev, 'KERN-A'),
                'B': self._cgpt_handler.get_partition(rootdev, 'KERN-B')
        }

    def set_attributes(self, a=None, b=None):
        """Set kernel attributes for either partition (or both)."""
        partitions = {'A': a, 'B': b}
        rootdev = self._os_if.get_root_dev()
        modifiable_attributes = self._cgpt_handler.ATTR_TO_COMMAND.keys()
        for partition_name in partitions.keys():
            partition = partitions[partition_name]
            if partition is None:
                continue
            attributes_to_set = {
                    key: partition[key]
                    for key in modifiable_attributes
            }
            if attributes_to_set:
                self._cgpt_handler.set_partition(
                        rootdev, 'KERN-%s' % partition_name, attributes_to_set)


class EcServicer(object):
    """Class to service all EC RPCs"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if

        # This attribute is accessed via a property, so it can load lazily
        # when actually used by the test.
        self._real_ec_handler = None
        ec_status = self._os_if.run_shell_command_get_status('mosys ec info')
        if ec_status == 0:
            self._real_ec_handler = flashrom_handler.FlashromHandler(
                    self._os_if, 'ec_root_key.vpubk',
                    '/usr/share/vboot/devkeys', 'ec')

        else:
            self._os_if.log('No EC is reported by mosys (rc=%s).' % ec_status)

    @property
    def _ec_handler(self):
        """Return the EC flashrom handler, after initializing it if necessary

        @rtype: flashrom_handler.FlashromHandler
        """
        if not self._real_ec_handler:
            # No EC handler if board has no EC
            return None

        if not self._real_ec_handler.initialized:
            self._real_ec_handler.init()
        return self._real_ec_handler

    def reload(self):
        """Reload the firmware image that may be changed."""
        self._ec_handler.new_image()

    def get_version(self):
        """Get EC version via mosys.

        @return: A string of the EC version.
        """
        return self._os_if.run_shell_command_get_output(
                'mosys ec info | sed "s/.*| //"')[0]

    def get_active_hash(self):
        """Get hash of active EC RW firmware."""
        return self._os_if.run_shell_command_get_output(
                'ectool echash | grep hash: | sed "s/hash:\s\+//"')[0]

    def dump_whole(self, ec_path):
        """Dump the current EC firmware to a file, specified by ec_path.

        @param ec_path: The path of the EC image to be written.
        """
        self._ec_handler.dump_whole(ec_path)

    def write_whole(self, ec_path):
        """Write the firmware from ec_path to the current system.

        @param ec_path: The path of the source EC image.
        """
        self._ec_handler.new_image(ec_path)
        self._ec_handler.write_whole()

    def corrupt_body(self, section):
        """Corrupt the requested EC section body.

        @param section: An EC section, either 'a' or 'b'.
        """
        self._ec_handler.corrupt_firmware_body(section, corrupt_all=True)

    def dump_firmware(self, ec_path):
        """Dump the current EC firmware to a file, specified by ec_path.

        @param ec_path: The path of the EC image to be written.
        """
        self._ec_handler.dump_whole(ec_path)

    def set_write_protect(self, enable):
        """Enable write protect of the EC flash chip.

        @param enable: True if activating EC write protect. Otherwise, False.
        """
        if enable:
            self._ec_handler.enable_write_protect()
        else:
            self._ec_handler.disable_write_protect()

    def get_write_protect_status(self):
        """Get a dict describing the status of the write protection

        @return: {'enabled': True/False, 'start': '0x0', 'length': '0x0', ...}
        @rtype: dict
        """
        return self._ec_handler.get_write_protect_status()

    def is_efs(self):
        """Return True if the EC supports EFS."""
        return self._ec_handler.has_section_body('rw_b')

    def copy_rw(self, from_section, to_section):
        """Copy EC RW from from_section to to_section."""
        self._ec_handler.copy_from_to(from_section, to_section)

    def reboot_to_switch_slot(self):
        """Reboot EC to switch the active RW slot."""
        self._os_if.run_shell_command(
                'ectool reboot_ec cold switch-slot', modifies_device=True)

    def strip_modified_fwids(self):
        """Strip trailing suffixes out of the FWIDs (see modify_image_fwids)."""
        return self._ec_handler.strip_modified_fwids()

    def get_write_cmd(self, image=None):
        """Get the command needed to write the whole image to the device.

        @param image: the filename (empty to use current handler data)
        """
        if image:
            # Don't bother loading the usual image, since it's overridden.
            return self._real_ec_handler.get_write_cmd(image)
        else:
            return self._ec_handler.get_write_cmd()


class KernelServicer(object):
    """Class to service all Kernel RPCs"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if
        self._real_kernel_handler = kernel_handler.KernelHandler(self._os_if)

    @property
    def _kernel_handler(self):
        """Return the kernel handler, after initializing it if necessary

        @rtype: kernel_handler.KernelHandler
        """
        if not self._real_kernel_handler.initialized:
            self._real_kernel_handler.init(
                    dev_key_path='/usr/share/vboot/devkeys',
                    internal_disk=True)
        return self._real_kernel_handler

    def corrupt_sig(self, section):
        """Corrupt the requested kernel section.

        @param section: A kernel section, either 'a' or 'b'.
        """
        self._kernel_handler.corrupt_kernel(section)

    def restore_sig(self, section):
        """Restore the requested kernel section (previously corrupted).

        @param section: A kernel section, either 'a' or 'b'.
        """
        self._kernel_handler.restore_kernel(section)

    def _modify_version(self, section, delta):
        """Modify kernel version for the requested section, by adding delta.

        The passed in delta, a positive or a negative number, is added to the
        original kernel version.
        """
        original_version = self._kernel_handler.get_version(section)
        new_version = original_version + delta
        self._os_if.log('Setting kernel section %s version from %d to %d' %
                        (section, original_version, new_version))
        self._kernel_handler.set_version(section, new_version)

    def move_version_backward(self, section):
        """Decrement kernel version for the requested section."""
        self._modify_version(section, -1)

    def move_version_forward(self, section):
        """Increase kernel version for the requested section."""
        self._modify_version(section, 1)

    def get_version(self, section):
        """Return kernel version."""
        return self._kernel_handler.get_version(section)

    def get_datakey_version(self, section):
        """Return kernel datakey version."""
        return self._kernel_handler.get_datakey_version(section)

    def diff_a_b(self):
        """Compare kernel A with B.

        @return: True: if kernel A is different with B.
                 False: if kernel A is the same as B.
        """
        rootdev = self._os_if.get_root_dev()
        kernel_a = self._os_if.join_part(rootdev, '2')
        kernel_b = self._os_if.join_part(rootdev, '4')

        # The signature (some kind of hash) for the kernel body is stored in
        # the beginning. So compare the first 64KB (including header, preamble,
        # and signature) should be enough to check them identical.
        header_a = self._os_if.read_partition(kernel_a, 0x10000)
        header_b = self._os_if.read_partition(kernel_b, 0x10000)

        return header_a != header_b

    def resign_with_keys(self, section, key_path=None):
        """Resign kernel with temporary key."""
        self._kernel_handler.resign_kernel(section, key_path)

    def dump(self, section, kernel_path):
        """Dump the specified kernel to a file.

        @param section: The kernel to dump. May be A or B.
        @param kernel_path: The path to the kernel image to be written.
        """
        self._kernel_handler.dump_kernel(section, kernel_path)

    def write(self, section, kernel_path):
        """Write a kernel image to the specified section.

        @param section: The kernel to dump. May be A or B.
        @param kernel_path: The path to the kernel image.
        """
        self._kernel_handler.write_kernel(section, kernel_path)

    def get_sha(self, section):
        """Return the SHA1 hash of the specified kernel section."""
        return self._kernel_handler.get_sha(section)


class RootfsServicer(object):
    """Class to service all RootFS RPCs"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if
        self._real_rootfs_handler = rootfs_handler.RootfsHandler(self._os_if)

    @property
    def _rootfs_handler(self):
        """Return the rootfs handler, after initializing it if necessary

        @rtype: rootfs_handler.RootfsHandler
        """
        if not self._real_rootfs_handler.initialized:
            self._real_rootfs_handler.init()
        return self._real_rootfs_handler

    def verify_rootfs(self, section):
        """Verifies the integrity of the root FS.

        @param section: The rootfs to verify. May be A or B.
        """
        return self._rootfs_handler.verify_rootfs(section)


class RpcSettingsServicer(object):
    """Class to service RPCs for settings of the RPC server itself"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if

    def enable_test_mode(self):
        """Enable test mode (avoids writing to flash or gpt)"""
        self._os_if.test_mode = True

    def disable_test_mode(self):
        """Disable test mode and return to normal operation"""
        self._os_if.test_mode = False


class SystemServicer(object):
    """Class to service all System RPCs"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if
        self._key_checker = firmware_check_keys.firmwareCheckKeys()

    def is_available(self):
        """Function for polling the RPC server availability.

        @return: Always True.
        """
        return True

    def dump_log(self, remove_log=False):
        """Dump the log file.

        @param remove_log: Remove the log file after dump.
        @return: String of the log file content.
        """
        return self._os_if.dump_log(remove_log=remove_log)

    def run_shell_command(self, command, block=True):
        """Run shell command.

        @param command: A shell command to be run.
        @param block: if True (default), wait for command to finish
        """
        self._os_if.run_shell_command(command, block=block)

    def run_shell_command_check_output(self, command, success_token):
        """Run shell command and check its stdout for a string.

        @param command: A shell command to be run.
        @param success_token: A string to search the output for.
        @return: A Boolean indicating whether the success_token was found in
                the command output.
        """
        return self._os_if.run_shell_command_check_output(
                command, success_token)

    def run_shell_command_get_output(self, command, include_stderr=False):
        """Run shell command and get its console output.

        @param command: A shell command to be run.
        @return: A list of strings stripped of the newline characters.
        """
        return self._os_if.run_shell_command_get_output(command, include_stderr)

    def run_shell_command_get_status(self, command):
        """Run shell command and get its console status.

        @param command: A shell command to be run.
        @return: The returncode of the process
        @rtype: int
        """
        return self._os_if.run_shell_command_get_status(command)

    def get_platform_name(self):
        """Get the platform name of the current system.

        @return: A string of the platform name.
        """
        return lsbrelease_utils.get_current_board()

    def get_model_name(self):
        """Get the model name of the current system.

        @return: A string of the model name.
        """
        model = cros_config.call_cros_config_get_output(
                '/ name', self._os_if.run_shell_command_get_result)
        if not model:
            raise Exception('Failed getting model name from cros_config')
        return model

    def dev_tpm_present(self):
        """Check if /dev/tpm0 is present.

        @return: Boolean true or false.
        """
        return os.path.exists('/dev/tpm0')

    def get_crossystem_value(self, key):
        """Get crossystem value of the requested key.

        @param key: A crossystem key.
        @return: A string of the requested crossystem value.
        """
        return self._os_if.run_shell_command_get_output(
                'crossystem %s' % key)[0]

    def get_root_dev(self):
        """Get the name of root device without partition number.

        @return: A string of the root device without partition number.
        """
        return self._os_if.get_root_dev()

    def get_root_part(self):
        """Get the name of root device with partition number.

        @return: A string of the root device with partition number.
        """
        return self._os_if.get_root_part()

    def set_try_fw_b(self, count=1):
        """Set 'Try Firmware B' flag in crossystem.

        @param count: # times to try booting into FW B
        """
        self._os_if.cs.fwb_tries = count

    def set_fw_try_next(self, next, count=0):
        """Set fw_try_next to A or B.

        @param next: Next FW to reboot to (A or B)
        @param count: # of times to try booting into FW <next>
        """
        self._os_if.cs.fw_try_next = next
        if count:
            self._os_if.cs.fw_try_count = count

    def get_fw_vboot2(self):
        """Get fw_vboot2."""
        try:
            return self._os_if.cs.fw_vboot2 == '1'
        except os_interface.OSInterfaceError:
            return False

    def request_recovery_boot(self):
        """Request running in recovery mode on the restart."""
        self._os_if.cs.request_recovery()

    def get_dev_boot_usb(self):
        """Get dev_boot_usb value which controls developer mode boot from USB.

        @return: True if enable, False if disable.
        """
        return self._os_if.cs.dev_boot_usb == '1'

    def set_dev_boot_usb(self, value):
        """Set dev_boot_usb value which controls developer mode boot from USB.

        @param value: True to enable, False to disable.
        """
        self._os_if.cs.dev_boot_usb = 1 if value else 0

    def get_dev_default_boot(self):
        """Get dev_default_boot value, which selects the default boot device.

        @return: 'disk' or 'usb' or 'legacy'
        """
        return self._os_if.cs.dev_default_boot

    def set_dev_default_boot(self, device='disk'):
        """Set dev_default_boot value, which selects the default boot device.

        @param device: 'disk' or 'usb' or 'legacy' (default: 'disk')
        """
        self._os_if.cs.dev_default_boot = device

    def is_removable_device_boot(self):
        """Check the current boot device is removable.

        @return: True: if a removable device boots.
                 False: if a non-removable device boots.
        """
        root_part = self._os_if.get_root_part()
        return self._os_if.is_removable_device(root_part)

    def get_internal_device(self):
        """Get the internal disk by given the current disk."""
        root_part = self._os_if.get_root_part()
        return self._os_if.get_internal_disk(root_part)

    def create_temp_dir(self, prefix='backup_', dir=None):
        """Create a temporary directory and return the path."""
        return tempfile.mkdtemp(prefix=prefix, dir=dir)

    def remove_file(self, file_path):
        """Remove the file."""
        return self._os_if.remove_file(file_path)

    def remove_dir(self, dir_path):
        """Remove the directory."""
        return self._os_if.remove_dir(dir_path)

    def check_keys(self, expected_sequence):
        """Check the keys sequence was as expected.

        @param expected_sequence: A list of expected key sequences.
        """
        return self._key_checker.check_keys(expected_sequence)


class TpmServicer(object):
    """Class to service all TPM RPCs"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if

        # This attribute is accessed via a property, so it can load lazily
        # when actually used by the test.
        self._real_tpm_handler = tpm_handler.TpmHandler(self._os_if)

    @property
    def _tpm_handler(self):
        """Handler for the TPM

        @rtype: tpm_handler.TpmHandler
        """
        if not self._real_tpm_handler.initialized:
            self._real_tpm_handler.init()
        return self._real_tpm_handler

    def get_firmware_version(self):
        """Retrieve tpm firmware body version."""
        return self._tpm_handler.get_fw_version()

    def get_firmware_datakey_version(self):
        """Retrieve tpm firmware data key version."""
        return self._tpm_handler.get_fw_key_version()

    def get_kernel_version(self):
        """Retrieve tpm kernel body version."""
        return self._tpm_handler.get_kernel_version()

    def get_kernel_datakey_version(self):
        """Retrieve tpm kernel data key version."""
        return self._tpm_handler.get_kernel_key_version()

    def get_tpm_version(self):
        """Returns '1.2' or '2.0' as a string."""
        # tpmc can return this without stopping daemons, so access real handler.
        return self._real_tpm_handler.get_tpm_version()

    def stop_daemon(self):
        """Stop tpm related daemon."""
        return self._tpm_handler.stop_daemon()

    def restart_daemon(self):
        """Restart tpm related daemon which was stopped by stop_daemon()."""
        return self._tpm_handler.restart_daemon()


class UpdaterServicer(object):
    """Class to service all Updater RPCs"""

    def __init__(self, os_if):
        """
        @type os_if: os_interface.OSInterface
        """
        self._os_if = os_if
        self._real_updater = firmware_updater.FirmwareUpdater(self._os_if)

    @property
    def _updater(self):
        """Handler for the updater

        @rtype: firmware_updater.FirmwareUpdater
        """
        if not self._real_updater.initialized:
            self._real_updater.init()
        return self._real_updater

    def cleanup(self):
        """Clean up the temporary directory"""
        # Use the updater directly, to avoid initializing it just to clean it up
        self._real_updater.cleanup_temp_dir()

    def stop_daemon(self):
        """Stop update-engine daemon."""
        return self._real_updater.stop_daemon()

    def start_daemon(self):
        """Start update-engine daemon."""
        return self._real_updater.start_daemon()

    def get_section_fwid(self, target='bios', section=None):
        """Retrieve shellball's RW or RO fwid."""
        return self._updater.get_section_fwid(target, section)

    def get_device_fwids(self, target='bios'):
        """Retrieve flash device's fwids for the target."""
        return self._updater.get_device_fwids(target)

    def get_image_fwids(self, target='bios', filename=None):
        """Retrieve image file's fwids for the target."""
        return self._updater.get_image_fwids(target, filename)

    def modify_image_fwids(self, target='bios', sections=None):
        """Modify the fwid in the image, but don't flash it."""
        return self._updater.modify_image_fwids(target, sections)

    def modify_ecid_and_flash_to_bios(self):
        """Modify ecid, put it to AP firmware, and flash it to the system."""
        self._updater.modify_ecid_and_flash_to_bios()

    def corrupt_diagnostics_image(self, local_filename):
        """Corrupts a diagnostics image in the CBFS working directory.

        @param local_filename: Filename for storing the diagnostics image in the
            CBFS working directory
        """
        self._updater.corrupt_diagnostics_image(local_filename)

    def get_ec_hash(self):
        """Return the hex string of the EC hash."""
        blob = self._updater.get_ec_hash()
        # Format it to a hex string
        return binascii.hexlify(blob)

    def resign_firmware(self, version):
        """Resign firmware with version.

        @param version: new version number.
        """
        self._updater.resign_firmware(version)

    def extract_shellball(self, append=None):
        """Extract shellball with the given append suffix.

        @param append: use for the shellball name.
        """
        return self._updater.extract_shellball(append)

    def repack_shellball(self, append=None):
        """Repack shellball with new fwid.

        @param append: use for the shellball name.
        """
        return self._updater.repack_shellball(append)

    def reset_shellball(self):
        """Revert to the stock shellball"""
        self._updater.reset_shellball()

    def reload_images(self):
        """Reload handlers from the on-disk images, in case they've changed."""
        self._updater.reload_images()

    def get_firmwareupdate_command(self, mode, append=None, options=()):
        """Get the command needed to run updater with the given options.

        The client should run it via ssh, in case the update resets USB network.

        @param mode: mode for the updater
        @param append: extra string appended to shellball filename to run
        @param options: options for chromeos-firmwareupdate
        @return: returncode of the updater
        @rtype: str
        """
        return self._updater.get_firmwareupdate_command(mode, append, options)

    def run_firmwareupdate(self, mode, append=None, options=()):
        """Run updater with the given options

        @param mode: mode for the updater
        @param append: extra string appended to shellball filename to run
        @param options: options for chromeos-firmwareupdate
        @return: returncode of the updater
        @rtype: int
        """
        return self._updater.run_firmwareupdate(mode, append, options)

    def run_autoupdate(self, append):
        """Run chromeos-firmwareupdate with autoupdate mode."""
        options = ['--noupdate_ec', '--wp=1']
        self._updater.run_firmwareupdate(
                mode='autoupdate', append=append, options=options)

    def run_factory_install(self):
        """Run chromeos-firmwareupdate with factory_install mode."""
        options = ['--noupdate_ec', '--wp=0']
        self._updater.run_firmwareupdate(
                mode='factory_install', options=options)

    def run_bootok(self, append):
        """Run chromeos-firmwareupdate with bootok mode."""
        self._updater.run_firmwareupdate(mode='bootok', append=append)

    def run_recovery(self):
        """Run chromeos-firmwareupdate with recovery mode."""
        options = ['--noupdate_ec', '--nocheck_keys', '--force', '--wp=1']
        self._updater.run_firmwareupdate(mode='recovery', options=options)

    def cbfs_setup_work_dir(self):
        """Sets up cbfstool work directory."""
        return self._updater.cbfs_setup_work_dir()

    def cbfs_extract_chip(self,
                          fw_name,
                          extension='.bin',
                          hash_extension='.hash'):
        """Runs cbfstool to extract chip firmware.

        @param fw_name: Name of chip firmware to extract.
        @return: Boolean success status.
        """
        return self._updater.cbfs_extract_chip(fw_name, extension,
                                               hash_extension)

    def cbfs_extract_diagnostics(self, diag_name, local_filename):
        """Runs cbfstool to extract a diagnostics image.

        @param diag_name: Name of the diagnostics image in CBFS
        @param local_filename: Filename for storing the diagnostics image in the
            CBFS working directory
        """
        self._updater.cbfs_extract_diagnostics(diag_name, local_filename)

    def cbfs_replace_diagnostics(self, diag_name, local_filename):
        """Runs cbfstool to replace a diagnostics image in the firmware image.

        @param diag_name: Name of the diagnostics image in CBFS
        @param local_filename: Filename for storing the diagnostics image in the
            CBFS working directory
        """
        self._updater.cbfs_replace_diagnostics(diag_name, local_filename)

    def cbfs_get_chip_hash(self, fw_name, hash_extension='.hash'):
        """Gets the chip firmware hash blob.

        The hash data is returned as a list of stringified two-byte pieces:
        \x12\x34...\xab\xcd\xef -> ['0x12', '0x34', ..., '0xab', '0xcd', '0xef']

        @param fw_name: Name of chip firmware whose hash blob to return.
        @return: Hex string of hash blob.
        """
        return self._updater.cbfs_get_chip_hash(fw_name, hash_extension)

    def cbfs_replace_chip(self,
                          fw_name,
                          extension='.bin',
                          hash_extension='.hash',
                          regions=('a', 'b')):
        """Runs cbfstool to replace chip firmware.

        @param fw_name: Name of chip firmware to extract.
        @return: Boolean success status.
        """
        return self._updater.cbfs_replace_chip(fw_name, extension,
                                               hash_extension, regions)

    def cbfs_sign_and_flash(self):
        """Runs cbfs signer and flash it.

        @param fw_name: Name of chip firmware to extract.
        @return: Boolean success status.
        """
        return self._updater.cbfs_sign_and_flash()

    def cbfs_extract(self,
                     filename,
                     extension,
                     regions,
                     local_filename=None,
                     arch=None,
                     bios=None):
        """Extracts an arbitrary file from cbfs.

        Note that extracting from
        @param filename: Filename in cbfs, including extension
        @param extension: Extension of the file, including '.'
        @param regions: Tuple of regions (the default is just 'a')
        @param arch: Specific machine architecture to extract (default unset)
        @param local_filename: Path to use on the DUT, overriding the default in
                           the cbfs work dir.
        @param bios: Image from which the cbfs file to be extracted
        @return: The full path of the extracted file, or None
        """
        return self._updater.cbfs_extract(filename,
                                      extension, regions,
                                      local_filename,
                                      arch,
                                      bios)

    def get_temp_path(self):
        """Get updater's temp directory path."""
        return self._updater.get_temp_path()

    def get_keys_path(self):
        """Get updater's keys directory path."""
        return self._updater.get_keys_path()

    def get_work_path(self):
        """Get updater's work directory path."""
        return self._updater.get_work_path()

    def get_bios_relative_path(self):
        """Gets the relative path of the bios image in the shellball."""
        return self._updater.get_bios_relative_path()

    def get_ec_relative_path(self):
        """Gets the relative path of the ec image in the shellball."""
        return self._updater.get_ec_relative_path()

    def copy_bios(self, filename):
        """Make a copy of the shellball bios.bin"""
        return self._updater.copy_bios(filename)

    def get_image_gbb_flags(self, filename=None):
        """Get the GBB flags in the given image (shellball image if unspecified)

        @param filename: the image path to act on (None to use shellball image)
        @return: An integer of the GBB flags.
        """
        return self._updater.get_image_gbb_flags(filename)

    def set_image_gbb_flags(self, flags, filename=None):
        """Set the GBB flags in the given image (shellball image if unspecified)

        @param flags: the flags to set
        @param filename: the image path to act on (None to use shellball image)

        @type flags: int
        @type filename: str | None
        """
        return self._updater.set_image_gbb_flags(flags, filename)