registry_operations.py

# Copyright 2020 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

import logging
import winreg

import win32api
import win32con
import winerror

LOGGER = logging.getLogger('installer_test')

_REGISTRY_VIEW_MAPPING = {
    'KEY_WOW64_32KEY': winreg.KEY_WOW64_32KEY,
    'KEY_WOW64_64KEY': winreg.KEY_WOW64_64KEY,
}

_ROOT_KEY_MAPPING = {
    'HKEY_CLASSES_ROOT': winreg.HKEY_CLASSES_ROOT,
    'HKEY_CURRENT_USER': winreg.HKEY_CURRENT_USER,
    'HKEY_LOCAL_MACHINE': winreg.HKEY_LOCAL_MACHINE,
    'HKEY_USERS': winreg.HKEY_USERS,
}


def _RootKeyConstant(root_key):
    """Converts a root registry key string into a winreg.HKEY_* constant."""
    if root_key not in _ROOT_KEY_MAPPING:
        raise KeyError("Unknown root registry key '%s'" % root_key)
    return _ROOT_KEY_MAPPING[root_key]


def _RegistryViewConstant(registry_view):
    """Converts a registry view string into a winreg.KEY_WOW64* constant."""
    if registry_view not in _REGISTRY_VIEW_MAPPING:
        raise KeyError("Unknown registry view '%s'" % registry_view)
    return _REGISTRY_VIEW_MAPPING[registry_view]


def _ValueTypeConstant(value_type):
    """Converts a registry value type string into a winreg.REG_* constant."""
    value_type_mapping = {
        'BINARY': winreg.REG_BINARY,
        'DWORD': winreg.REG_DWORD,
        'DWORD_LITTLE_ENDIAN': winreg.REG_DWORD_LITTLE_ENDIAN,
        'DWORD_BIG_ENDIAN': winreg.REG_DWORD_BIG_ENDIAN,
        'EXPAND_SZ': winreg.REG_EXPAND_SZ,
        'LINK': winreg.REG_LINK,
        'MULTI_SZ': winreg.REG_MULTI_SZ,
        'NONE': winreg.REG_NONE,
        'SZ': winreg.REG_SZ,
    }
    if value_type not in value_type_mapping:
        raise KeyError("Unknown registry value type '%s'" % value_type)
    return value_type_mapping[value_type]


def VerifyRegistryEntryExpectation(expectation_name, expectation,
                                   variable_expander):
    """Verifies a registry key according to the |expectation|.

    Args:
        expectation_name: The registry key being verified. It is expanded using
            Expand.
        expectation: A dictionary with the following keys and values:
            'exists' a string indicating whether the registry key's existence is
                'required', 'optional', or 'forbidden'. Values are not checked
                if an 'optional' key is not present in the registry.
            'values' (optional) a dictionary where each key is a registry value
                (which is expanded using Expand) and its associated value is a
                dictionary with the following key and values:
                    'type' (optional) a string indicating the type of the
                        registry value. If not present, the corresponding value
                        is expected to be absent in the registry.
                    'data' (optional) the associated data of the registry value
                        if 'type' is specified. If it is a string, it is
                        expanded using Expand. If not present, only the value's
                        type is verified.
            'wow_key' (optional) a string indicating whether the view of the
                registry is KEY_WOW64_32KEY or KEY_WOW64_64KEY. If not present,
                the view of registry is determined by the bitness of the
                installer binary.
        variable_expander: A VariableExpander object.

    Raises:
        AssertionError: If an expectation is not satisfied.
    """
    key = variable_expander.Expand(expectation_name)
    root_key, sub_key = key.split('\\', 1)
    try:
        # Query the Windows registry for the registry key. It will throw a
        # WindowsError if the key doesn't exist.
        registry_view = winreg.KEY_WOW64_32KEY
        if 'wow_key' in expectation:
            registry_view = _RegistryViewConstant(expectation['wow_key'])
        elif variable_expander.Expand('$MINI_INSTALLER_BITNESS') == '64':
            # Note that $MINI_INSTALLER_BITNESS == '64' for x64 and for ARM64.
            registry_view = winreg.KEY_WOW64_64KEY

        key_handle = winreg.OpenKey(_RootKeyConstant(root_key), sub_key, 0,
                                    winreg.KEY_QUERY_VALUE | registry_view)
    except WindowsError:
        # Key doesn't exist. See that it matches the expectation.
        assert expectation['exists'] != 'required', ('Registry key %s is '
                                                     'missing' % key)
        # Values are not checked if the missing key's existence is optional.
        return
    # The key exists, see that it matches the expectation.
    assert expectation['exists'] != 'forbidden', ('Registry key %s exists' %
                                                  key)

    # Verify the expected values.
    if 'values' not in expectation:
        return
    for value, value_expectation in expectation['values'].items():
        # Query the value. It will throw a WindowsError if the value doesn't
        # exist.
        value = variable_expander.Expand(value)
        try:
            data, value_type = winreg.QueryValueEx(key_handle, value)
        except WindowsError:
            # The value does not exist. See that this matches the expectation.
            assert 'type' not in value_expectation, (
                'Value %s of registry key %s '
                'is missing' % (value, key))
            continue

        assert 'type' in value_expectation, (
            'Value %s of registry key %s exists '
            'with value %s' % (value, key, data))

        # Verify the type of the value.
        expected_value_type = value_expectation['type']
        assert _ValueTypeConstant(expected_value_type) == value_type, \
            "Value '%s' of registry key %s has unexpected type '%s'" % (
                value, key, expected_value_type)

        if 'data' not in value_expectation:
            return

        # Verify the associated data of the value.
        expected_data = value_expectation['data']
        if isinstance(expected_data, str):
            expected_data = variable_expander.Expand(expected_data)
        assert expected_data == data, \
            ("Value '%s' of registry key %s has unexpected data.\n"
             "  Expected: %s\n"
             "  Actual: %s" % (value, key, expected_data, data))


def CleanRegistryEntry(expectation_name, expectation, variable_expander):
    """Cleans registry keys and/or values based on expectations.

    Args:
        expectation_name: The registry key being cleaned.
        expectation: A dictionary describing the state of the key:
            'exists': Either the string 'forbidden', indicating that the key is
                to be deleted if it is found, or the string 'optional',
                indicating that specific values in the key are to be deleted if
                the key exists.
            'values' (optional): For a key with 'optional' existence, a
                dictionary mapping value names to empty dicts, indicating that
                the values are to be deleted.
        variable_expander: A VariableExpander object.

    Raises:
        AssertionError: If an expectation is not satisfied.
        WindowsError: If an error occurs while cleaning the registry.
    """
    key = variable_expander.Expand(expectation_name)
    assert not expectation['exists'] == 'required', (
        'Invalid expectation for CleanRegistryEntry operation: \'exists\' ' +
        'property for key %s must not be \'required\'' % key)
    root_key, sub_key = key.split('\\', 1)

    registry_view = winreg.KEY_WOW64_32KEY
    if 'wow_key' in expectation:
        registry_view = _RegistryViewConstant(expectation['wow_key'])
    elif variable_expander.Expand('$MINI_INSTALLER_BITNESS') == '64':
        # Note that $MINI_INSTALLER_BITNESS == '64' for x64 and for ARM64.
        registry_view = winreg.KEY_WOW64_64KEY

    try:
        # Query the Windows registry for the registry key. It will throw a
        # WindowsError if the key doesn't exist.
        key_handle = winreg.OpenKey(_RootKeyConstant(root_key), sub_key, 0,
                                    (winreg.KEY_SET_VALUE | registry_view))
    except WindowsError:
        # There is nothing to clean if the key doesn't exist.
        return

    if expectation['exists'] == 'forbidden':
        # RegDeleteTree must be called with a handle on some parent of the key
        # to be deleted in order for it to remove the key itself and not only
        # its values and subkeys. Open the root of the hive with the proper
        # permissions, then delete the key by name.
        key_handle = None
        root_handle = winreg.OpenKey(
            _RootKeyConstant(root_key), None, 0,
            (win32con.DELETE | winreg.KEY_ENUMERATE_SUB_KEYS
             | winreg.KEY_QUERY_VALUE | winreg.KEY_SET_VALUE
             | registry_view))
        win32api.RegDeleteTree(root_handle, sub_key)
        LOGGER.info('CleanRegistryEntry deleted key %s' % key)
        return

    assert 'values' in expectation and expectation['values'], (
        'Invalid expectation for CleanRegistryEntry operation: a \'values\' ' +
        'dictionary is required for optional key %s' % key)
    for value, value_expectation in expectation['values'].items():
        value = variable_expander.Expand(value)
        assert 'type' not in value_expectation, (
            'Invalid expectation for CleanRegistryEntry operation: value ' +
            '%s\\%s must not specify a \'type\'' % (key, value))
        try:
            winreg.DeleteValue(key_handle, value)
            LOGGER.info('CleanRegistryEntry deleted value %s\\%s' %
                        (key, value))
        except WindowsError as e:
            if e.winerror == winerror.ERROR_FILE_NOT_FOUND:
                continue
            raise