Mbed TLS configuration file manipulation library and tool
This is meant to be a drop-in replacement for config.pl which can
additionally be used as a library in a Python script.
So far this script supports the commands 'get', 'set' and 'realfull'
but not the other built-in configurations.
diff --git a/scripts/config.py b/scripts/config.py
new file mode 100755
index 0000000..f86d64b
--- /dev/null
+++ b/scripts/config.py
@@ -0,0 +1,298 @@
+#!/usr/bin/env python3
+
+"""Mbed TLS configuration file manipulation library and tool
+
+Basic usage, to read the Mbed TLS or Mbed Crypto configuration:
+ config = ConfigFile()
+ if 'MBEDTLS_RSA_C' in config: print('RSA is enabled')
+"""
+
+## Copyright (C) 2019, ARM Limited, All Rights Reserved
+## SPDX-License-Identifier: Apache-2.0
+##
+## Licensed under the Apache License, Version 2.0 (the "License"); you may
+## not use this file except in compliance with the License.
+## You may obtain a copy of the License at
+##
+## http://www.apache.org/licenses/LICENSE-2.0
+##
+## Unless required by applicable law or agreed to in writing, software
+## distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+## WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+## See the License for the specific language governing permissions and
+## limitations under the License.
+##
+## This file is part of Mbed TLS (https://tls.mbed.org)
+
+import re
+
+class Setting:
+ """Representation of one Mbed TLS config.h setting.
+
+ Fields:
+ * name: the symbol name ('MBEDTLS_xxx').
+ * value: the value of the macro. The empty string for a plain #define
+ with no value.
+ * active: True if name is defined, False if a #define for name is
+ present in config.h but commented out.
+ """
+ # pylint: disable=too-few-public-methods
+ def __init__(self, active, name, value=''):
+ self.active = active
+ self.name = name
+ self.value = value
+
+class Config:
+ """Representation of the Mbed TLS configuration.
+
+ In the documentation of this class, a symbol is said to be *active*
+ if there is a #define for it that is not commented out, and *known*
+ if there is a #define for it whether commented out or not.
+
+ This class supports the following protocols:
+ * `name in config` is True if the symbol `name` is set in the
+ configuration, False otherwise (whether `name` is known but commented
+ out or not known at all).
+ * `config[name]` is the value of the macro `name`. If `name` is not
+ set, raise `KeyError` (even if a definition for `name` is present
+ but commented out).
+ * `config[name] = value` sets the value associated to `name`. `name`
+ must be known, but does not need to be set. This does not cause
+ name to become set.
+ """
+
+ def __init__(self):
+ self.settings = {}
+
+ def __contains__(self, name):
+ """True if the given symbol is active (i.e. set).
+
+ False if the given symbol is not set, even if a definition
+ is present but commented out.
+ """
+ return name in self.settings and self.settings[name].active
+
+ def all(self, *names):
+ """True if all the elements of names are active (i.e. set)."""
+ return all(self.__contains__(name) for name in names)
+
+ def any(self, *names):
+ """True if at least one symbol in names are active (i.e. set)."""
+ return any(self.__contains__(name) for name in names)
+
+ def known(self, name):
+ """True if a #define for name is present, whether it's commented out or not."""
+ return name in self.settings
+
+ def __getitem__(self, name):
+ """Get the value of name, i.e. what the preprocessor symbol expands to.
+
+ If name is not known, raise KeyError. name does not need to be active.
+ """
+ return self.settings[name].value
+
+ def get(self, name, default=None):
+ """Get the value of name. If name is inactive (not set), return default.
+
+ If a #define for name is present and not commented out, return
+ its expansion, even if this is the empty string.
+
+ If a #define for name is present but commented out, return default.
+ """
+ if name in self.settings:
+ return self.settings[name].value
+ else:
+ return default
+
+ def __setitem__(self, name, value):
+ """If name is known, set its value.
+
+ If name is not known, raise KeyError.
+ """
+ self.settings[name].value = value
+
+ def set(self, name, value=None):
+ """Set name to the given value and make it active.
+
+ If value is None and name is already known, don't change its value.
+ If value is None and name is not known, set its value to the empty
+ string.
+ """
+ if name in self.settings:
+ if value is not None:
+ self.settings[name].value = value
+ self.settings[name].active = True
+ else:
+ self.settings[name] = Setting(True, name, value=value)
+
+ def unset(self, name):
+ """Make name unset (inactive).
+
+ name remains known.
+ """
+ self.set(name)
+ self.settings[name].active = False
+
+ def adapt(self, adapter):
+ """Run adapter on each known symbol and (de)activate it accordingly.
+
+ `adapter` must be a function that returns a boolean. It is called as
+ `adapter(name, active)` for each setting, where `active` is `True`
+ if `name` is set and `False` if `name` is known but unset. If
+ `adapter` returns `True`, then set `name` (i.e. make it active),
+ otherwise unset `name` (i.e. make it known but inactive).
+ """
+ for setting in self.settings.values():
+ setting.active = adapter(setting.name, setting.active)
+
+def realfull_adapter(_name, _set):
+ """Uncomment everything."""
+ return True
+
+class ConfigFile(Config):
+ """Representation of the Mbed TLS configuration read for a file.
+
+ See the documentation of the `Config` class for methods to query
+ and modify the configuration.
+ """
+
+ default_path = 'include/mbedtls/config.h'
+
+ def __init__(self, filename=None):
+ """Read the Mbed TLS configuration file."""
+ if filename is None:
+ filename = self.default_path
+ super().__init__()
+ self.filename = filename
+ with open(filename) as file:
+ self.templates = [self._parse_line(line) for line in file]
+
+ def set(self, name, value=None):
+ if name not in self.settings:
+ self.templates.append((name, '', '#define ' + name + ' '))
+ super().set(name, value)
+
+ _define_line_regexp = (r'(?P<indentation>\s*)' +
+ r'(?P<commented_out>(//\s*)?)' +
+ r'(?P<define>#\s*define\s+)' +
+ r'(?P<name>\w+)' +
+ r'(?P<arguments>(?:\((?:\w|\s|,)*\))?)' +
+ r'(?P<separator>\s*)' +
+ r'(?P<value>.*)')
+ def _parse_line(self, line):
+ """Parse a line in config.h and return the corresponding template."""
+ line = line.rstrip('\r\n')
+ m = re.match(self._define_line_regexp, line)
+ if m:
+ active = not m.group('commented_out')
+ name = m.group('name')
+ value = m.group('value')
+ template = (name,
+ m.group('indentation'),
+ m.group('define') + name +
+ m.group('arguments') + m.group('separator'))
+ self.settings[name] = Setting(active, name, value)
+ return template
+ else:
+ return line
+
+ def _format_template(self, name, indent, middle):
+ """Build a line for config.h for the given setting.
+
+ The line has the form "<indent>#define <name><middle> <value>".
+ """
+ setting = self.settings[name]
+ return ''.join([indent,
+ '' if setting.active else '//',
+ middle,
+ setting.value]).rstrip()
+
+ def write_to_stream(self, output):
+ """Write the whole configuration to output."""
+ for template in self.templates:
+ if isinstance(template, str):
+ line = template
+ else:
+ line = self._format_template(*template)
+ output.write(line + '\n')
+
+ def write(self, filename=None):
+ """Write the whole configuration to the file it was read from.
+
+ If filename is specified, write to this file instead.
+ """
+ if filename is None:
+ filename = self.filename
+ with open(filename, 'w') as output:
+ self.write_to_stream(output)
+
+if __name__ == '__main__':
+ def main():
+ """Command line config.h manipulation tool."""
+ parser = argparse.ArgumentParser(description="""
+ Mbed TLS and Mbed Crypto configuration file manipulation tool.
+ """)
+ parser.add_argument('--file', '-f',
+ help="""File to read (and modify if requested).
+ Default: {}.
+ """.format(ConfigFile.default_path))
+ parser.add_argument('--force', '-o',
+ help="""For the set command, if SYMBOL is not
+ present, add a definition for it.""")
+ subparsers = parser.add_subparsers(dest='command',
+ title='Commands')
+ parser_get = subparsers.add_parser('get',
+ help="""Find the value of SYMBOL
+ and print it. Exit with
+ status 0 if a #define for SYMBOL is
+ found, 1 otherwise.
+ """)
+ parser_get.add_argument('symbol', metavar='SYMBOL')
+ parser_set = subparsers.add_parser('set',
+ help="""Set SYMBOL to VALUE.
+ If VALUE is omitted, just uncomment
+ the #define for SYMBOL.
+ Error out of a line defining
+ SYMBOL (commented or not) is not
+ found, unless --force is passed.
+ """)
+ parser_set.add_argument('symbol', metavar='SYMBOL')
+ parser_set.add_argument('value', metavar='VALUE', nargs='?')
+ parser_unset = subparsers.add_parser('unset',
+ help="""Comment out the #define
+ for SYMBOL. Do nothing if none
+ is present.""")
+ parser_unset.add_argument('symbol', metavar='SYMBOL')
+
+ def add_adapter(name, function, description):
+ subparser = subparsers.add_parser(name, help=description)
+ subparser.set_defaults(adapter=function)
+ add_adapter('realfull', realfull_adapter,
+ """Uncomment all #defines. No exceptions.""")
+
+ args = parser.parse_args()
+ config = ConfigFile(args.file)
+ if args.command == 'get':
+ if args.symbol in config:
+ value = config[args.symbol]
+ if value:
+ sys.stdout.write(value + '\n')
+ return args.symbol not in config
+ elif args.command == 'set':
+ if not args.force and args.symbol not in config:
+ sys.stderr.write("A #define for the symbol {} "
+ "was not found in {}"
+ .format(args.symbol, args.file))
+ return 1
+ config.set(args.symbol, value=args.value)
+ elif args.command == 'unset':
+ config.unset(args.symbol)
+ else:
+ config.adapt(args.adapter)
+ config.write()
+
+ # 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())
