523 lines
22 KiB
Python
Executable File
523 lines
22 KiB
Python
Executable File
#!/usr/bin/env python3
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"""Mbed TLS configuration file manipulation library and tool
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Basic usage, to read the Mbed TLS or Mbed Crypto configuration:
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config = ConfigFile()
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if 'MBEDTLS_RSA_C' in config: print('RSA is enabled')
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"""
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## Copyright The Mbed TLS Contributors
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## SPDX-License-Identifier: Apache-2.0
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##
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## Licensed under the Apache License, Version 2.0 (the "License"); you may
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## not use this file except in compliance with the License.
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## You may obtain a copy of the License at
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##
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## http://www.apache.org/licenses/LICENSE-2.0
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##
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## Unless required by applicable law or agreed to in writing, software
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## distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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## WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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## See the License for the specific language governing permissions and
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## limitations under the License.
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import os
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import re
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class Setting:
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"""Representation of one Mbed TLS config.h setting.
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Fields:
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* name: the symbol name ('MBEDTLS_xxx').
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* value: the value of the macro. The empty string for a plain #define
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with no value.
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* active: True if name is defined, False if a #define for name is
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present in config.h but commented out.
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* section: the name of the section that contains this symbol.
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"""
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# pylint: disable=too-few-public-methods
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def __init__(self, active, name, value='', section=None):
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self.active = active
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self.name = name
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self.value = value
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self.section = section
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class Config:
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"""Representation of the Mbed TLS configuration.
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In the documentation of this class, a symbol is said to be *active*
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if there is a #define for it that is not commented out, and *known*
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if there is a #define for it whether commented out or not.
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This class supports the following protocols:
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* `name in config` is `True` if the symbol `name` is active, `False`
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otherwise (whether `name` is inactive or not known).
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* `config[name]` is the value of the macro `name`. If `name` is inactive,
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raise `KeyError` (even if `name` is known).
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* `config[name] = value` sets the value associated to `name`. `name`
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must be known, but does not need to be set. This does not cause
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name to become set.
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"""
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def __init__(self):
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self.settings = {}
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def __contains__(self, name):
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"""True if the given symbol is active (i.e. set).
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False if the given symbol is not set, even if a definition
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is present but commented out.
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"""
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return name in self.settings and self.settings[name].active
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def all(self, *names):
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"""True if all the elements of names are active (i.e. set)."""
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return all(self.__contains__(name) for name in names)
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def any(self, *names):
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"""True if at least one symbol in names are active (i.e. set)."""
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return any(self.__contains__(name) for name in names)
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def known(self, name):
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"""True if a #define for name is present, whether it's commented out or not."""
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return name in self.settings
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def __getitem__(self, name):
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"""Get the value of name, i.e. what the preprocessor symbol expands to.
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If name is not known, raise KeyError. name does not need to be active.
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"""
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return self.settings[name].value
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def get(self, name, default=None):
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"""Get the value of name. If name is inactive (not set), return default.
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If a #define for name is present and not commented out, return
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its expansion, even if this is the empty string.
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If a #define for name is present but commented out, return default.
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"""
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if name in self.settings:
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return self.settings[name].value
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else:
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return default
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def __setitem__(self, name, value):
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"""If name is known, set its value.
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If name is not known, raise KeyError.
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"""
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self.settings[name].value = value
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def set(self, name, value=None):
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"""Set name to the given value and make it active.
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If value is None and name is already known, don't change its value.
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If value is None and name is not known, set its value to the empty
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string.
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"""
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if name in self.settings:
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if value is not None:
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self.settings[name].value = value
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self.settings[name].active = True
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else:
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self.settings[name] = Setting(True, name, value=value)
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def unset(self, name):
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"""Make name unset (inactive).
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name remains known if it was known before.
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"""
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if name not in self.settings:
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return
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self.settings[name].active = False
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def adapt(self, adapter):
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"""Run adapter on each known symbol and (de)activate it accordingly.
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`adapter` must be a function that returns a boolean. It is called as
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`adapter(name, active, section)` for each setting, where `active` is
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`True` if `name` is set and `False` if `name` is known but unset,
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and `section` is the name of the section containing `name`. If
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`adapter` returns `True`, then set `name` (i.e. make it active),
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otherwise unset `name` (i.e. make it known but inactive).
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"""
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for setting in self.settings.values():
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setting.active = adapter(setting.name, setting.active,
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setting.section)
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def is_full_section(section):
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"""Is this section affected by "config.py full" and friends?"""
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return section.endswith('support') or section.endswith('modules')
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def realfull_adapter(_name, active, section):
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"""Activate all symbols found in the system and feature sections."""
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if not is_full_section(section):
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return active
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return True
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# The goal of the full configuration is to have everything that can be tested
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# together. This includes deprecated or insecure options. It excludes:
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# * Options that require additional build dependencies or unusual hardware.
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# * Options that make testing less effective.
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# * Options that are incompatible with other options, or more generally that
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# interact with other parts of the code in such a way that a bulk enabling
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# is not a good way to test them.
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# * Options that remove features.
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EXCLUDE_FROM_FULL = frozenset([
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#pylint: disable=line-too-long
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'MBEDTLS_CTR_DRBG_USE_128_BIT_KEY', # interacts with ENTROPY_FORCE_SHA256
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'MBEDTLS_DEPRECATED_REMOVED', # conflicts with deprecated options
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'MBEDTLS_DEPRECATED_WARNING', # conflicts with deprecated options
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'MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED', # influences the use of ECDH in TLS
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'MBEDTLS_ECP_NO_FALLBACK', # removes internal ECP implementation
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'MBEDTLS_ECP_NO_INTERNAL_RNG', # removes a feature
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'MBEDTLS_ECP_RESTARTABLE', # incompatible with USE_PSA_CRYPTO
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'MBEDTLS_ENTROPY_FORCE_SHA256', # interacts with CTR_DRBG_128_BIT_KEY
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'MBEDTLS_HAVE_SSE2', # hardware dependency
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'MBEDTLS_MEMORY_BACKTRACE', # depends on MEMORY_BUFFER_ALLOC_C
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'MBEDTLS_MEMORY_BUFFER_ALLOC_C', # makes sanitizers (e.g. ASan) less effective
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'MBEDTLS_MEMORY_DEBUG', # depends on MEMORY_BUFFER_ALLOC_C
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'MBEDTLS_NO_64BIT_MULTIPLICATION', # influences anything that uses bignum
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'MBEDTLS_NO_DEFAULT_ENTROPY_SOURCES', # removes a feature
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'MBEDTLS_NO_PLATFORM_ENTROPY', # removes a feature
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'MBEDTLS_NO_UDBL_DIVISION', # influences anything that uses bignum
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'MBEDTLS_PLATFORM_NO_STD_FUNCTIONS', # removes a feature
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'MBEDTLS_PSA_CRYPTO_CONFIG', # toggles old/new style PSA config
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'MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG', # behavior change + build dependency
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'MBEDTLS_PSA_CRYPTO_KEY_ID_ENCODES_OWNER', # incompatible with USE_PSA_CRYPTO
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'MBEDTLS_PSA_CRYPTO_SPM', # platform dependency (PSA SPM)
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'MBEDTLS_PSA_INJECT_ENTROPY', # build dependency (hook functions)
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'MBEDTLS_REMOVE_3DES_CIPHERSUITES', # removes a feature
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'MBEDTLS_RSA_NO_CRT', # influences the use of RSA in X.509 and TLS
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'MBEDTLS_SHA512_NO_SHA384', # removes a feature
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'MBEDTLS_TEST_CONSTANT_FLOW_MEMSAN', # build dependency (clang+memsan)
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'MBEDTLS_TEST_CONSTANT_FLOW_VALGRIND', # build dependency (valgrind headers)
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'MBEDTLS_TEST_NULL_ENTROPY', # removes a feature
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'MBEDTLS_X509_ALLOW_UNSUPPORTED_CRITICAL_EXTENSION', # influences the use of X.509 in TLS
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])
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def is_seamless_alt(name):
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"""Whether the xxx_ALT symbol should be included in the full configuration.
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Include alternative implementations of platform functions, which are
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configurable function pointers that default to the built-in function.
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This way we test that the function pointers exist and build correctly
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without changing the behavior, and tests can verify that the function
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pointers are used by modifying those pointers.
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Exclude alternative implementations of library functions since they require
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an implementation of the relevant functions and an xxx_alt.h header.
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"""
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if name == 'MBEDTLS_PLATFORM_SETUP_TEARDOWN_ALT':
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# Similar to non-platform xxx_ALT, requires platform_alt.h
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return False
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return name.startswith('MBEDTLS_PLATFORM_')
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def include_in_full(name):
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"""Rules for symbols in the "full" configuration."""
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if name in EXCLUDE_FROM_FULL:
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return False
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if name.endswith('_ALT'):
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return is_seamless_alt(name)
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return True
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def full_adapter(name, active, section):
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"""Config adapter for "full"."""
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if not is_full_section(section):
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return active
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return include_in_full(name)
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# The baremetal configuration excludes options that require a library or
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# operating system feature that is typically not present on bare metal
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# systems. Features that are excluded from "full" won't be in "baremetal"
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# either (unless explicitly turned on in baremetal_adapter) so they don't
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# need to be repeated here.
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EXCLUDE_FROM_BAREMETAL = frozenset([
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#pylint: disable=line-too-long
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'MBEDTLS_ENTROPY_NV_SEED', # requires a filesystem and FS_IO or alternate NV seed hooks
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'MBEDTLS_FS_IO', # requires a filesystem
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'MBEDTLS_HAVE_TIME', # requires a clock
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'MBEDTLS_HAVE_TIME_DATE', # requires a clock
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'MBEDTLS_NET_C', # requires POSIX-like networking
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'MBEDTLS_PLATFORM_FPRINTF_ALT', # requires FILE* from stdio.h
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'MBEDTLS_PLATFORM_NV_SEED_ALT', # requires a filesystem and ENTROPY_NV_SEED
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'MBEDTLS_PLATFORM_TIME_ALT', # requires a clock and HAVE_TIME
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'MBEDTLS_PSA_CRYPTO_SE_C', # requires a filesystem and PSA_CRYPTO_STORAGE_C
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'MBEDTLS_PSA_CRYPTO_STORAGE_C', # requires a filesystem
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'MBEDTLS_PSA_ITS_FILE_C', # requires a filesystem
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'MBEDTLS_THREADING_C', # requires a threading interface
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'MBEDTLS_THREADING_PTHREAD', # requires pthread
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'MBEDTLS_TIMING_C', # requires a clock
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])
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def keep_in_baremetal(name):
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"""Rules for symbols in the "baremetal" configuration."""
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if name in EXCLUDE_FROM_BAREMETAL:
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return False
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return True
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def baremetal_adapter(name, active, section):
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"""Config adapter for "baremetal"."""
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if not is_full_section(section):
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return active
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if name == 'MBEDTLS_NO_PLATFORM_ENTROPY':
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# No OS-provided entropy source
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return True
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return include_in_full(name) and keep_in_baremetal(name)
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def include_in_crypto(name):
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"""Rules for symbols in a crypto configuration."""
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if name.startswith('MBEDTLS_X509_') or \
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name.startswith('MBEDTLS_SSL_') or \
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name.startswith('MBEDTLS_KEY_EXCHANGE_'):
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return False
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if name in [
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'MBEDTLS_DEBUG_C', # part of libmbedtls
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'MBEDTLS_NET_C', # part of libmbedtls
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]:
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return False
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return True
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def crypto_adapter(adapter):
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"""Modify an adapter to disable non-crypto symbols.
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``crypto_adapter(adapter)(name, active, section)`` is like
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``adapter(name, active, section)``, but unsets all X.509 and TLS symbols.
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"""
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def continuation(name, active, section):
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if not include_in_crypto(name):
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return False
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if adapter is None:
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return active
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return adapter(name, active, section)
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return continuation
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def no_deprecated_adapter(adapter):
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"""Modify an adapter to disable deprecated symbols.
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``no_deprecated_adapter(adapter)(name, active, section)`` is like
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``adapter(name, active, section)``, but unsets all deprecated symbols
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and sets ``MBEDTLS_DEPRECATED_REMOVED``.
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"""
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def continuation(name, active, section):
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if name == 'MBEDTLS_DEPRECATED_REMOVED':
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return True
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if adapter is None:
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return active
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return adapter(name, active, section)
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return continuation
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class ConfigFile(Config):
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"""Representation of the Mbed TLS configuration read for a file.
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See the documentation of the `Config` class for methods to query
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and modify the configuration.
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"""
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_path_in_tree = 'include/mbedtls/config.h'
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default_path = [_path_in_tree,
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os.path.join(os.path.dirname(__file__),
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os.pardir,
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_path_in_tree),
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os.path.join(os.path.dirname(os.path.abspath(os.path.dirname(__file__))),
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_path_in_tree)]
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def __init__(self, filename=None):
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"""Read the Mbed TLS configuration file."""
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if filename is None:
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for candidate in self.default_path:
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if os.path.lexists(candidate):
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filename = candidate
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break
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else:
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raise Exception('Mbed TLS configuration file not found',
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self.default_path)
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super().__init__()
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self.filename = filename
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self.current_section = 'header'
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with open(filename, 'r', encoding='utf-8') as file:
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self.templates = [self._parse_line(line) for line in file]
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self.current_section = None
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def set(self, name, value=None):
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if name not in self.settings:
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self.templates.append((name, '', '#define ' + name + ' '))
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super().set(name, value)
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_define_line_regexp = (r'(?P<indentation>\s*)' +
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r'(?P<commented_out>(//\s*)?)' +
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r'(?P<define>#\s*define\s+)' +
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r'(?P<name>\w+)' +
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r'(?P<arguments>(?:\((?:\w|\s|,)*\))?)' +
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r'(?P<separator>\s*)' +
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r'(?P<value>.*)')
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_section_line_regexp = (r'\s*/?\*+\s*[\\@]name\s+SECTION:\s*' +
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r'(?P<section>.*)[ */]*')
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_config_line_regexp = re.compile(r'|'.join([_define_line_regexp,
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_section_line_regexp]))
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def _parse_line(self, line):
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"""Parse a line in config.h and return the corresponding template."""
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line = line.rstrip('\r\n')
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m = re.match(self._config_line_regexp, line)
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if m is None:
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return line
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elif m.group('section'):
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self.current_section = m.group('section')
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return line
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else:
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active = not m.group('commented_out')
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name = m.group('name')
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value = m.group('value')
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template = (name,
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m.group('indentation'),
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m.group('define') + name +
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m.group('arguments') + m.group('separator'))
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self.settings[name] = Setting(active, name, value,
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self.current_section)
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return template
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def _format_template(self, name, indent, middle):
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"""Build a line for config.h for the given setting.
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The line has the form "<indent>#define <name> <value>"
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where <middle> is "#define <name> ".
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"""
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setting = self.settings[name]
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value = setting.value
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if value is None:
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value = ''
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# Normally the whitespace to separte the symbol name from the
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# value is part of middle, and there's no whitespace for a symbol
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# with no value. But if a symbol has been changed from having a
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# value to not having one, the whitespace is wrong, so fix it.
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if value:
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if middle[-1] not in '\t ':
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middle += ' '
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else:
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middle = middle.rstrip()
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return ''.join([indent,
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'' if setting.active else '//',
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middle,
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value]).rstrip()
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def write_to_stream(self, output):
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"""Write the whole configuration to output."""
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for template in self.templates:
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if isinstance(template, str):
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line = template
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else:
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line = self._format_template(*template)
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output.write(line + '\n')
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def write(self, filename=None):
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"""Write the whole configuration to the file it was read from.
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If filename is specified, write to this file instead.
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"""
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if filename is None:
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filename = self.filename
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with open(filename, 'w', encoding='utf-8') as output:
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self.write_to_stream(output)
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if __name__ == '__main__':
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def main():
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"""Command line config.h manipulation tool."""
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parser = argparse.ArgumentParser(description="""
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Mbed TLS and Mbed Crypto configuration file manipulation tool.
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""")
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parser.add_argument('--file', '-f',
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help="""File to read (and modify if requested).
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Default: {}.
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""".format(ConfigFile.default_path))
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parser.add_argument('--force', '-o',
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action='store_true',
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help="""For the set command, if SYMBOL is not
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present, add a definition for it.""")
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parser.add_argument('--write', '-w', metavar='FILE',
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help="""File to write to instead of the input file.""")
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subparsers = parser.add_subparsers(dest='command',
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title='Commands')
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parser_get = subparsers.add_parser('get',
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help="""Find the value of SYMBOL
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and print it. Exit with
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status 0 if a #define for SYMBOL is
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found, 1 otherwise.
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""")
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parser_get.add_argument('symbol', metavar='SYMBOL')
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parser_set = subparsers.add_parser('set',
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help="""Set SYMBOL to VALUE.
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If VALUE is omitted, just uncomment
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the #define for SYMBOL.
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Error out of a line defining
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SYMBOL (commented or not) is not
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found, unless --force is passed.
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""")
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parser_set.add_argument('symbol', metavar='SYMBOL')
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parser_set.add_argument('value', metavar='VALUE', nargs='?',
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default='')
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parser_unset = subparsers.add_parser('unset',
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help="""Comment out the #define
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for SYMBOL. Do nothing if none
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is present.""")
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parser_unset.add_argument('symbol', metavar='SYMBOL')
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def add_adapter(name, function, description):
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subparser = subparsers.add_parser(name, help=description)
|
|
subparser.set_defaults(adapter=function)
|
|
add_adapter('baremetal', baremetal_adapter,
|
|
"""Like full, but exclude features that require platform
|
|
features such as file input-output.""")
|
|
add_adapter('full', full_adapter,
|
|
"""Uncomment most features.
|
|
Exclude alternative implementations and platform support
|
|
options, as well as some options that are awkward to test.
|
|
""")
|
|
add_adapter('full_no_deprecated', no_deprecated_adapter(full_adapter),
|
|
"""Uncomment most non-deprecated features.
|
|
Like "full", but without deprecated features.
|
|
""")
|
|
add_adapter('realfull', realfull_adapter,
|
|
"""Uncomment all boolean #defines.
|
|
Suitable for generating documentation, but not for building.""")
|
|
add_adapter('crypto', crypto_adapter(None),
|
|
"""Only include crypto features. Exclude X.509 and TLS.""")
|
|
add_adapter('crypto_baremetal', crypto_adapter(baremetal_adapter),
|
|
"""Like baremetal, but with only crypto features,
|
|
excluding X.509 and TLS.""")
|
|
add_adapter('crypto_full', crypto_adapter(full_adapter),
|
|
"""Like full, but with only crypto features,
|
|
excluding X.509 and TLS.""")
|
|
|
|
args = parser.parse_args()
|
|
config = ConfigFile(args.file)
|
|
if args.command is None:
|
|
parser.print_help()
|
|
return 1
|
|
elif args.command == 'get':
|
|
if args.symbol in config:
|
|
value = config[args.symbol]
|
|
if value:
|
|
sys.stdout.write(value + '\n')
|
|
return 0 if args.symbol in config else 1
|
|
elif args.command == 'set':
|
|
if not args.force and args.symbol not in config.settings:
|
|
sys.stderr.write("A #define for the symbol {} "
|
|
"was not found in {}\n"
|
|
.format(args.symbol, config.filename))
|
|
return 1
|
|
config.set(args.symbol, value=args.value)
|
|
elif args.command == 'unset':
|
|
config.unset(args.symbol)
|
|
else:
|
|
config.adapt(args.adapter)
|
|
config.write(args.write)
|
|
return 0
|
|
|
|
# Import modules only used by main only if main is defined and called.
|
|
# pylint: disable=wrong-import-position
|
|
import argparse
|
|
import sys
|
|
sys.exit(main())
|