win_reg.py

# -*- coding: utf-8 -*-
'''
Manage the Windows registry

-----
Hives
-----
Hives are the main sections of the registry and all begin with the word HKEY.

    - HKEY_LOCAL_MACHINE
    - HKEY_CURRENT_USER
    - HKEY_USER

----
Keys
----
Keys are the folders in the registry. Keys can have many nested subkeys. Keys
can have a value assigned to them under the (Default) value name

-----------------
Values or Entries
-----------------
Values/Entries are name/data pairs. There can be many values in a key. The
(Default) value corresponds to the Key itself, the rest are their own name/value
pairs.

:depends:   - PyWin32
'''
# When production windows installer is using Python 3, Python 2 code can be removed
from __future__ import absolute_import, print_function, unicode_literals

# Import python libs
import sys
import logging
from salt.ext.six.moves import range  # pylint: disable=W0622,import-error

# Import third party libs
try:
    import win32gui
    import win32api
    import win32con
    import pywintypes
    HAS_WINDOWS_MODULES = True
except ImportError:
    HAS_WINDOWS_MODULES = False

# Import Salt libs
import salt.utils.platform
import salt.utils.stringutils
from salt.exceptions import CommandExecutionError
from salt.ext import six

PY2 = sys.version_info[0] == 2
log = logging.getLogger(__name__)

# Define the module's virtual name
__virtualname__ = 'reg'


def __virtual__():
    '''
    Only works on Windows systems with the PyWin32
    '''
    if not salt.utils.platform.is_windows():
        return (False, 'reg execution module failed to load: '
                       'The module will only run on Windows systems')

    if not HAS_WINDOWS_MODULES:
        return (False, 'reg execution module failed to load: '
                       'One of the following libraries did not load: '
                       'win32gui, win32con, win32api')

    return __virtualname__


def _to_mbcs(vdata):
    '''
    Converts unicode to to current users character encoding. Use this for values
    returned by reg functions
    '''
    return salt.utils.stringutils.to_unicode(vdata, 'mbcs')


def _to_unicode(vdata):
    '''
    Converts from current users character encoding to unicode. Use this for
    parameters being pass to reg functions
    '''
    # None does not convert to Unicode
    if vdata is None:
        return None
    return salt.utils.stringutils.to_unicode(vdata, 'utf-8')


class Registry(object):  # pylint: disable=R0903
    '''
    This was put in a class to delay usage until this module is actually used
    This class contains all the lookup dicts for working with the registry
    '''
    def __init__(self):
        self.hkeys = {
            'HKEY_CURRENT_CONFIG': win32con.HKEY_CURRENT_CONFIG,
            'HKEY_CLASSES_ROOT': win32con.HKEY_CLASSES_ROOT,
            'HKEY_CURRENT_USER':  win32con.HKEY_CURRENT_USER,
            'HKEY_LOCAL_MACHINE': win32con.HKEY_LOCAL_MACHINE,
            'HKEY_USERS': win32con.HKEY_USERS,
            'HKCC': win32con.HKEY_CURRENT_CONFIG,
            'HKCR': win32con.HKEY_CLASSES_ROOT,
            'HKCU': win32con.HKEY_CURRENT_USER,
            'HKLM': win32con.HKEY_LOCAL_MACHINE,
            'HKU':  win32con.HKEY_USERS,
        }
        self.vtype = {
            'REG_BINARY':    win32con.REG_BINARY,
            'REG_DWORD':     win32con.REG_DWORD,
            'REG_EXPAND_SZ': win32con.REG_EXPAND_SZ,
            'REG_MULTI_SZ':  win32con.REG_MULTI_SZ,
            'REG_SZ':        win32con.REG_SZ,
            'REG_QWORD':     win32con.REG_QWORD
        }
        self.opttype = {
            'REG_OPTION_NON_VOLATILE': 0,
            'REG_OPTION_VOLATILE':     1
        }
        # Return Unicode due to from __future__ import unicode_literals
        self.vtype_reverse = {
            win32con.REG_BINARY:    'REG_BINARY',
            win32con.REG_DWORD:     'REG_DWORD',
            win32con.REG_EXPAND_SZ: 'REG_EXPAND_SZ',
            win32con.REG_MULTI_SZ:  'REG_MULTI_SZ',
            win32con.REG_SZ:        'REG_SZ',
            win32con.REG_QWORD:     'REG_QWORD'
        }
        self.opttype_reverse = {
            0: 'REG_OPTION_NON_VOLATILE',
            1: 'REG_OPTION_VOLATILE'
        }
        # delete_key_recursive uses this to check the subkey contains enough \
        # as we do not want to remove all or most of the registry
        self.subkey_slash_check = {
            win32con.HKEY_CURRENT_USER:   0,
            win32con.HKEY_LOCAL_MACHINE:  1,
            win32con.HKEY_USERS:          1,
            win32con.HKEY_CURRENT_CONFIG: 1,
            win32con.HKEY_CLASSES_ROOT:   1
        }

        self.registry_32 = {
            True: win32con.KEY_READ | win32con.KEY_WOW64_32KEY,
            False: win32con.KEY_READ,
        }

    def __getattr__(self, k):
        try:
            return self.hkeys[k]
        except KeyError:
            msg = 'No hkey named \'{0}. Try one of {1}\''
            hkeys = ', '.join(self.hkeys)
            raise CommandExecutionError(msg.format(k, hkeys))


def key_exists(hive, key, use_32bit_registry=False):
    '''
    Check that the key is found in the registry. This refers to keys and not
    value/data pairs. To check value/data pairs, use ``value_exists``

    Args:

        hive (str): The hive to connect to

        key (str): The key to check

        use_32bit_registry (bool): Look in the 32bit portion of the registry

    Returns:
        bool: True if exists, otherwise False

    Usage:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.key_exists(hive='HKLM', key='SOFTWARE\\Microsoft')
    '''
    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)

    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError('Invalid Hive: {0}'.format(local_hive))
    access_mask = registry.registry_32[use_32bit_registry]

    handle = None
    try:
        handle = win32api.RegOpenKeyEx(hkey, local_key, 0, access_mask)
        return True
    except pywintypes.error as exc:
        if exc.winerror == 2:
            return False
        raise
    finally:
        if handle:
            win32api.RegCloseKey(handle)


def value_exists(hive, key, vname, use_32bit_registry=False):
    '''
    Check that the value/data pair is found in the registry.

    .. version-added:: 2018.3.4

    Args:

        hive (str): The hive to connect to

        key (str): The key to check in

        vname (str): The name of the value/data pair you're checking

        use_32bit_registry (bool): Look in the 32bit portion of the registry

    Returns:
        bool: True if exists, otherwise False

    Usage:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.key_exists(hive='HKLM', key='SOFTWARE\\Microsoft')
    '''
    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)
    local_vname = _to_unicode(vname)

    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError('Invalid Hive: {0}'.format(local_hive))
    access_mask = registry.registry_32[use_32bit_registry]

    try:
        handle = win32api.RegOpenKeyEx(hkey, local_key, 0, access_mask)
    except pywintypes.error as exc:
        if exc.winerror == 2:
            # The key containing the value/data pair does not exist
            return False
        raise

    try:
        # RegQueryValueEx returns and accepts unicode data
        _, _ = win32api.RegQueryValueEx(handle, local_vname)
        # value/data pair exists
        return True
    except pywintypes.error as exc:
        if exc.winerror == 2 and vname is None:
            # value/data pair exists but is empty
            return True
        else:
            # value/data pair not found
            return False
    finally:
        win32api.RegCloseKey(handle)


def broadcast_change():
    '''
    Refresh the windows environment.

    .. note::
        This will only effect new processes and windows. Services will not see
        the change until the system restarts.

    Returns:
        bool: True if successful, otherwise False

    Usage:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.broadcast_change()
    '''
    # https://msdn.microsoft.com/en-us/library/windows/desktop/ms644952(v=vs.85).aspx
    _, res = win32gui.SendMessageTimeout(
        win32con.HWND_BROADCAST, win32con.WM_SETTINGCHANGE, 0, 0,
        win32con.SMTO_ABORTIFHUNG, 5000)
    return not bool(res)


def list_keys(hive, key=None, use_32bit_registry=False):
    '''
    Enumerates the subkeys in a registry key or hive.

    Args:

       hive (str):
            The name of the hive. Can be one of the following:

                - HKEY_LOCAL_MACHINE or HKLM
                - HKEY_CURRENT_USER or HKCU
                - HKEY_USERS or HKU
                - HKEY_CLASSES_ROOT or HKCR
                - HKEY_CURRENT_CONFIG or HKCC

        key (str):
            The key (looks like a path) to the value name. If a key is not
            passed, the keys under the hive will be returned.

        use_32bit_registry (bool):
            Accesses the 32bit portion of the registry on 64 bit installations.
            On 32bit machines this is ignored.

    Returns:
        list: A list of keys/subkeys under the hive or key.

    Usage:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.list_keys(hive='HKLM', key='SOFTWARE\\Microsoft')
    '''

    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)

    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError('Invalid Hive: {0}'.format(local_hive))
    access_mask = registry.registry_32[use_32bit_registry]

    subkeys = []
    handle = None
    try:
        handle = win32api.RegOpenKeyEx(hkey, local_key, 0, access_mask)

        for i in range(win32api.RegQueryInfoKey(handle)[0]):
            subkey = win32api.RegEnumKey(handle, i)
            if PY2:
                subkeys.append(_to_mbcs(subkey))
            else:
                subkeys.append(subkey)

    except Exception:  # pylint: disable=E0602
        log.debug(r'Cannot find key: %s\%s', hive, key, exc_info=True)
        return False, r'Cannot find key: {0}\{1}'.format(hive, key)
    finally:
        if handle:
            handle.Close()

    return subkeys


def list_values(hive, key=None, use_32bit_registry=False, include_default=True):
    '''
    Enumerates the values in a registry key or hive.

    Args:

        hive (str):
            The name of the hive. Can be one of the following:

                - HKEY_LOCAL_MACHINE or HKLM
                - HKEY_CURRENT_USER or HKCU
                - HKEY_USER or HKU
                - HKEY_CLASSES_ROOT or HKCR
                - HKEY_CURRENT_CONFIG or HKCC

        key (str):
            The key (looks like a path) to the value name. If a key is not
            passed, the values under the hive will be returned.

        use_32bit_registry (bool):
            Accesses the 32bit portion of the registry on 64 bit installations.
            On 32bit machines this is ignored.

        include_default (bool):
            Toggle whether to include the '(Default)' value.

    Returns:
        list: A list of values under the hive or key.

    Usage:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.list_values(hive='HKLM', key='SYSTEM\\CurrentControlSet\\Services\\Tcpip')
    '''
    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)

    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError('Invalid Hive: {0}'.format(local_hive))
    access_mask = registry.registry_32[use_32bit_registry]
    handle = None
    values = list()

    try:
        handle = win32api.RegOpenKeyEx(hkey, local_key, 0, access_mask)

        for i in range(win32api.RegQueryInfoKey(handle)[1]):
            vname, vdata, vtype = win32api.RegEnumValue(handle, i)

            if not vname:
                vname = "(Default)"

            value = {'hive':   local_hive,
                     'key':    local_key,
                     'vname':  _to_mbcs(vname),
                     'vtype':  registry.vtype_reverse[vtype],
                     'success': True}
            # Only convert text types to unicode
            if vtype == win32con.REG_MULTI_SZ:
                value['vdata'] = [_to_mbcs(i) for i in vdata]
            elif vtype in [win32con.REG_SZ, win32con.REG_EXPAND_SZ]:
                value['vdata'] = _to_mbcs(vdata)
            else:
                value['vdata'] = vdata
            values.append(value)
    except Exception as exc:  # pylint: disable=E0602
        log.debug(r'Cannot find key: %s\%s', hive, key, exc_info=True)
        return False, r'Cannot find key: {0}\{1}'.format(hive, key)
    finally:
        if handle:
            handle.Close()
    return values


def read_value(hive, key, vname=None, use_32bit_registry=False):
    r'''
    Reads a registry value entry or the default value for a key. To read the
    default value, don't pass ``vname``

    Args:

        hive (str): The name of the hive. Can be one of the following:

            - HKEY_LOCAL_MACHINE or HKLM
            - HKEY_CURRENT_USER or HKCU
            - HKEY_USER or HKU
            - HKEY_CLASSES_ROOT or HKCR
            - HKEY_CURRENT_CONFIG or HKCC

        key (str):
            The key (looks like a path) to the value name.

        vname (str):
            The value name. These are the individual name/data pairs under the
            key. If not passed, the key (Default) value will be returned.

        use_32bit_registry (bool):
            Accesses the 32bit portion of the registry on 64bit installations.
            On 32bit machines this is ignored.

    Returns:
        dict: A dictionary containing the passed settings as well as the
            value_data if successful. If unsuccessful, sets success to False.

        bool: Returns False if the key is not found

        If vname is not passed:

            - Returns the first unnamed value (Default) as a string.
            - Returns none if first unnamed value is empty.

    Usage:

        The following will get the value of the ``version`` value name in the
        ``HKEY_LOCAL_MACHINE\\SOFTWARE\\Salt`` key

        .. code-block:: python

            import salt.utils.win_reg
            winreg.read_value(hive='HKLM', key='SOFTWARE\\Salt', vname='version')

    Usage:

        The following will get the default value of the
        ``HKEY_LOCAL_MACHINE\\SOFTWARE\\Salt`` key

        .. code-block:: python

            import salt.utils.win_reg
            winreg.read_value(hive='HKLM', key='SOFTWARE\\Salt')
    '''
    # If no name is passed, the default value of the key will be returned
    # The value name is Default

    # Setup the return array
    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)
    local_vname = _to_unicode(vname)

    ret = {'hive':  local_hive,
           'key':   local_key,
           'vname': local_vname,
           'vdata': None,
           'success': True}

    if not vname:
        ret['vname'] = '(Default)'

    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError('Invalid Hive: {0}'.format(local_hive))
    access_mask = registry.registry_32[use_32bit_registry]

    try:
        handle = win32api.RegOpenKeyEx(hkey, local_key, 0, access_mask)
        try:
            # RegQueryValueEx returns and accepts unicode data
            vdata, vtype = win32api.RegQueryValueEx(handle, local_vname)
            if vdata or vdata in [0, '']:
                # Only convert text types to unicode
                ret['vtype'] = registry.vtype_reverse[vtype]
                if vtype == win32con.REG_MULTI_SZ:
                    ret['vdata'] = [_to_mbcs(i) for i in vdata]
                elif vtype in [win32con.REG_SZ, win32con.REG_EXPAND_SZ]:
                    ret['vdata'] = _to_mbcs(vdata)
                else:
                    ret['vdata'] = vdata
            else:
                ret['comment'] = 'Empty Value'
        except Exception as exc:
            if exc.winerror == 2 and vname is None:
                ret['vdata'] = ('(value not set)')
                ret['vtype'] = 'REG_SZ'
            else:
                msg = 'Cannot find {0} in {1}\\{2}' \
                      ''.format(local_vname, local_hive, local_key)
                log.trace(exc)
                log.trace(msg)
                ret['comment'] = msg
                ret['success'] = False
    except Exception as exc:  # pylint: disable=E0602
        msg = 'Cannot find key: {0}\\{1}'.format(local_hive, local_key)
        log.trace(exc)
        log.trace(msg)
        ret['comment'] = msg
        ret['success'] = False
    return ret


def set_value(hive,
              key,
              vname=None,
              vdata=None,
              vtype='REG_SZ',
              use_32bit_registry=False,
              volatile=False):
    '''
    Sets a value in the registry. If ``vname`` is passed, it will be the value
    for that value name, otherwise it will be the default value for the
    specified key

    Args:

        hive (str):
            The name of the hive. Can be one of the following

                - HKEY_LOCAL_MACHINE or HKLM
                - HKEY_CURRENT_USER or HKCU
                - HKEY_USER or HKU
                - HKEY_CLASSES_ROOT or HKCR
                - HKEY_CURRENT_CONFIG or HKCC

        key (str):
            The key (looks like a path) to the value name.

        vname (str):
            The value name. These are the individual name/data pairs under the
            key. If not passed, the key (Default) value will be set.

        vdata (str, int, list, bytes):
            The value you'd like to set. If a value name (vname) is passed, this
            will be the data for that value name. If not, this will be the
            (Default) value for the key.

            The type of data this parameter expects is determined by the value
            type specified in ``vtype``. The correspondence is as follows:

                - REG_BINARY: Binary data (str in Py2, bytes in Py3)
                - REG_DWORD: int
                - REG_EXPAND_SZ: str
                - REG_MULTI_SZ: list of str
                - REG_QWORD: int
                - REG_SZ: str

                .. note::
                    When setting REG_BINARY, string data will be converted to
                    binary. You can pass base64 encoded using the ``binascii``
                    built-in module. Use ``binascii.b2a_base64('your data')``

            .. note::
                The type for the (Default) value is always REG_SZ and cannot be
                changed.

            .. note::
                This parameter is optional. If not passed, the Key will be
                created with no associated item/value pairs.

        vtype (str):
            The value type. The possible values of the vtype parameter are
            indicated above in the description of the vdata parameter.

        use_32bit_registry (bool):
            Sets the 32bit portion of the registry on 64bit installations. On
            32bit machines this is ignored.

        volatile (bool):
            When this parameter has a value of True, the registry key will be
            made volatile (i.e. it will not persist beyond a system reset or
            shutdown). This parameter only has an effect when a key is being
            created and at no other time.

    Returns:
        bool: True if successful, otherwise False

    Usage:

        This will set the version value to 2015.5.2 in the SOFTWARE\\Salt key in
        the HKEY_LOCAL_MACHINE hive

        .. code-block:: python

            import salt.utils.win_reg
            winreg.set_value(hive='HKLM', key='SOFTWARE\\Salt', vname='version', vdata='2015.5.2')

    Usage:

        This function is strict about the type of vdata. For instance this
        example will fail because vtype has a value of REG_SZ and vdata has a
        type of int (as opposed to str as expected).

        .. code-block:: python

            import salt.utils.win_reg
            winreg.set_value(hive='HKLM', key='SOFTWARE\\Salt', vname='str_data', vdata=1.2)

    Usage:

        In this next example vdata is properly quoted and should succeed.

        .. code-block:: python

            import salt.utils.win_reg
            winreg.set_value(hive='HKLM', key='SOFTWARE\\Salt', vname='str_data', vdata='1.2')

    Usage:

        This is an example of using vtype REG_BINARY. Both ``set_value``
        commands will set the same value ``Salty Test``

        .. code-block:: python

            import salt.utils.win_reg
            winreg.set_value(hive='HKLM', key='SOFTWARE\\Salt', vname='bin_data', vdata='Salty Test', vtype='REG_BINARY')

            import binascii
            bin_data = binascii.b2a_base64('Salty Test')
            winreg.set_value(hive='HKLM', key='SOFTWARE\\Salt', vname='bin_data_encoded', vdata=bin_data, vtype='REG_BINARY')

    Usage:

        An example using vtype REG_MULTI_SZ is as follows:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.set_value(hive='HKLM', key='SOFTWARE\\Salt', vname='list_data', vdata=['Salt', 'is', 'great'], vtype='REG_MULTI_SZ')
    '''
    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)
    local_vname = _to_unicode(vname)
    local_vtype = _to_unicode(vtype)

    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError('Invalid Hive: {0}'.format(local_hive))
    vtype_value = registry.vtype[local_vtype]
    access_mask = registry.registry_32[use_32bit_registry] | win32con.KEY_ALL_ACCESS

    local_vdata = cast_vdata(vdata=vdata, vtype=local_vtype)

    if volatile:
        create_options = registry.opttype['REG_OPTION_VOLATILE']
    else:
        create_options = registry.opttype['REG_OPTION_NON_VOLATILE']

    handle = None
    try:
        handle, _ = win32api.RegCreateKeyEx(hkey, local_key, access_mask,
                                            Options=create_options)
        win32api.RegSetValueEx(handle, local_vname, 0, vtype_value, local_vdata)
        win32api.RegFlushKey(handle)
        broadcast_change()
        return True
    except (win32api.error, SystemError, ValueError, TypeError):  # pylint: disable=E0602
        log.exception('Encountered error setting registry value')
        return False
    finally:
        if handle:
            win32api.RegCloseKey(handle)


def cast_vdata(vdata=None, vtype='REG_SZ'):
    '''
    Cast the ``vdata` value to the appropriate data type for the registry type
    specified in ``vtype``

    Args:

        vdata (str, int, list, bytes): The data to cast

        vtype (str):
            The type of data to be written to the registry. Must be one of the
            following:

                - REG_BINARY
                - REG_DWORD
                - REG_EXPAND_SZ
                - REG_MULTI_SZ
                - REG_QWORD
                - REG_SZ

    Returns:
        The vdata cast to the appropriate type. Will be unicode string, binary,
        list of unicode strings, or int

    Usage:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.cast_vdata(vdata='This is the string', vtype='REG_SZ')
    '''
    # Check data type and cast to expected type
    # int will automatically become long on 64bit numbers
    # https://www.python.org/dev/peps/pep-0237/

    registry = Registry()
    vtype_value = registry.vtype[vtype]

    # String Types to Unicode
    if vtype_value in [win32con.REG_SZ, win32con.REG_EXPAND_SZ]:
        return _to_unicode(vdata)
    # Don't touch binary... if it's binary
    elif vtype_value == win32con.REG_BINARY:
        if isinstance(vdata, six.text_type):
            # Unicode data must be encoded
            return vdata.encode('utf-8')
        return vdata
    # Make sure REG_MULTI_SZ is a list of strings
    elif vtype_value == win32con.REG_MULTI_SZ:
        return [_to_unicode(i) for i in vdata]
    # Make sure REG_QWORD is a 64 bit integer
    elif vtype_value == win32con.REG_QWORD:
        return vdata if six.PY3 else long(vdata)  # pylint: disable=W1699
    # Everything else is int
    else:
        return int(vdata)


def delete_key_recursive(hive, key, use_32bit_registry=False):
    '''
    .. versionadded:: 2015.5.4

    Delete a registry key to include all subkeys and value/data pairs.

    Args:

        hive (str):
            The name of the hive. Can be one of the following

                - HKEY_LOCAL_MACHINE or HKLM
                - HKEY_CURRENT_USER or HKCU
                - HKEY_USER or HKU
                - HKEY_CLASSES_ROOT or HKCR
                - HKEY_CURRENT_CONFIG or HKCC

            key (str):
                The key to remove (looks like a path)

            use_32bit_registry (bool):
                Deletes the 32bit portion of the registry on 64bit
                installations. On 32bit machines this is ignored.

    Returns:
        dict: A dictionary listing the keys that deleted successfully as well as
            those that failed to delete.

    Usage:

        The following example will remove ``salt`` and all its subkeys from the
        ``SOFTWARE`` key in ``HKEY_LOCAL_MACHINE``:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.delete_key_recursive(hive='HKLM', key='SOFTWARE\\DeleteMe')
    '''

    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)

    # Instantiate the registry object
    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError('Invalid Hive: {0}'.format(local_hive))
    key_path = local_key
    access_mask = registry.registry_32[use_32bit_registry] | win32con.KEY_ALL_ACCESS

    if not key_exists(local_hive, local_key, use_32bit_registry):
        return False

    if (len(key) > 1) and (key.count('\\', 1) < registry.subkey_slash_check[hkey]):
        log.error(
            'Hive:%s Key:%s; key is too close to root, not safe to remove',
            hive, key
        )
        return False

    # Functions for traversing the registry tree
    def _subkeys(_key):
        '''
        Enumerate keys
        '''
        i = 0
        while True:
            try:
                subkey = win32api.RegEnumKey(_key, i)
                yield _to_mbcs(subkey)
                i += 1
            except Exception:  # pylint: disable=E0602
                break

    def _traverse_registry_tree(_hkey, _keypath, _ret, _access_mask):
        '''
        Traverse the registry tree i.e. dive into the tree
        '''
        _key = win32api.RegOpenKeyEx(_hkey, _keypath, 0, _access_mask)
        for subkeyname in _subkeys(_key):
            subkeypath = '{0}\\{1}'.format(_keypath, subkeyname)
            _ret = _traverse_registry_tree(_hkey, subkeypath, _ret, access_mask)
            _ret.append(subkeypath)
        return _ret

    # Get a reverse list of registry keys to be deleted
    key_list = []
    key_list = _traverse_registry_tree(hkey, key_path, key_list, access_mask)
    # Add the top level key last, all subkeys must be deleted first
    key_list.append(key_path)

    ret = {'Deleted': [],
           'Failed': []}

    # Delete all sub_keys
    for sub_key_path in key_list:
        try:
            key_handle = win32api.RegOpenKeyEx(hkey, sub_key_path, 0, access_mask)
            win32api.RegDeleteKey(key_handle, '')
            ret['Deleted'].append(r'{0}\{1}'.format(hive, sub_key_path))
        except WindowsError as exc:  # pylint: disable=E0602
            log.error(exc, exc_info=True)
            ret['Failed'].append(r'{0}\{1} {2}'.format(hive, sub_key_path, exc))

    broadcast_change()

    return ret


def delete_value(hive, key, vname=None, use_32bit_registry=False):
    '''
    Delete a registry value entry or the default value for a key.

    Args:

        hive (str):
            The name of the hive. Can be one of the following

                - HKEY_LOCAL_MACHINE or HKLM
                - HKEY_CURRENT_USER or HKCU
                - HKEY_USER or HKU
                - HKEY_CLASSES_ROOT or HKCR
                - HKEY_CURRENT_CONFIG or HKCC

        key (str):
            The key (looks like a path) to the value name.

        vname (str):
            The value name. These are the individual name/data pairs under the
            key. If not passed, the key (Default) value will be deleted.

        use_32bit_registry (bool):
            Deletes the 32bit portion of the registry on 64bit installations. On
            32bit machines this is ignored.

    Return:
        bool: True if successful, otherwise False

    Usage:

        .. code-block:: python

            import salt.utils.win_reg
            winreg.delete_value(hive='HKLM', key='SOFTWARE\\SaltTest', vname='version')
    '''
    local_hive = _to_unicode(hive)
    local_key = _to_unicode(key)
    local_vname = _to_unicode(vname)

    registry = Registry()
    try:
        hkey = registry.hkeys[local_hive]
    except KeyError:
        raise CommandExecutionError('Invalid Hive: {0}'.format(local_hive))
    access_mask = registry.registry_32[use_32bit_registry] | win32con.KEY_ALL_ACCESS

    handle = None
    try:
        handle = win32api.RegOpenKeyEx(hkey, local_key, 0, access_mask)
        win32api.RegDeleteValue(handle, local_vname)
        broadcast_change()
        return True
    except Exception as exc:  # pylint: disable=E0602
        if exc.winerror == 2:
            return None
        else:
            log.error(exc, exc_info=True)
            log.error('Hive: %s', local_hive)
            log.error('Key: %s', local_key)
            log.error('ValueName: %s', local_vname)
            log.error('32bit Reg: %s', use_32bit_registry)
            return False
    finally:
        if handle:
            win32api.RegCloseKey(handle)