1#!/usr/bin/env python3
2"""Generate library/psa_crypto_driver_wrappers.h
3            library/psa_crypto_driver_wrappers_no_static.c
4
5   This module is invoked by the build scripts to auto generate the
6   psa_crypto_driver_wrappers.h and psa_crypto_driver_wrappers_no_static
7   based on template files in script/data_files/driver_templates/.
8"""
9# Copyright The Mbed TLS Contributors
10# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
11
12import sys
13import os
14import json
15from typing import NewType, Dict, Any
16from traceback import format_tb
17import argparse
18import jsonschema
19import jinja2
20from mbedtls_dev import build_tree
21
22JSONSchema = NewType('JSONSchema', object)
23# The Driver is an Object, but practically it's indexable and can called a dictionary to
24# keep MyPy happy till MyPy comes with a more composite type for JsonObjects.
25Driver = NewType('Driver', dict)
26
27
28class JsonValidationException(Exception):
29    def __init__(self, message="Json Validation Failed"):
30        self.message = message
31        super().__init__(self.message)
32
33
34class DriverReaderException(Exception):
35    def __init__(self, message="Driver Reader Failed"):
36        self.message = message
37        super().__init__(self.message)
38
39
40def render(template_path: str, driver_jsoncontext: list) -> str:
41    """
42    Render template from the input file and driver JSON.
43    """
44    environment = jinja2.Environment(
45        loader=jinja2.FileSystemLoader(os.path.dirname(template_path)),
46        keep_trailing_newline=True)
47    template = environment.get_template(os.path.basename(template_path))
48
49    return template.render(drivers=driver_jsoncontext)
50
51def generate_driver_wrapper_file(template_dir: str,
52                                 output_dir: str,
53                                 template_file_name: str,
54                                 driver_jsoncontext: list) -> None:
55    """
56    Generate the file psa_crypto_driver_wrapper.c.
57    """
58    driver_wrapper_template_filename = \
59        os.path.join(template_dir, template_file_name)
60
61    result = render(driver_wrapper_template_filename, driver_jsoncontext)
62
63    with open(file=os.path.join(output_dir, os.path.splitext(template_file_name)[0]),
64              mode='w',
65              encoding='UTF-8') as out_file:
66        out_file.write(result)
67
68
69def validate_json(driverjson_data: Driver, driverschema_list: dict) -> None:
70    """
71    Validate the Driver JSON against an appropriate schema
72    the schema passed could be that matching an opaque/ transparent driver.
73    """
74    driver_type = driverjson_data["type"]
75    driver_prefix = driverjson_data["prefix"]
76    try:
77        _schema = driverschema_list[driver_type]
78        jsonschema.validate(instance=driverjson_data, schema=_schema)
79    except KeyError as err:
80        # This could happen if the driverjson_data.type does not exist in the provided schema list
81        # schemas = {'transparent': transparent_driver_schema, 'opaque': opaque_driver_schema}
82        # Print onto stdout and stderr.
83        print("Unknown Driver type " + driver_type +
84              " for driver " + driver_prefix, str(err))
85        print("Unknown Driver type " + driver_type +
86              " for driver " + driver_prefix, str(err), file=sys.stderr)
87        raise JsonValidationException() from err
88
89    except jsonschema.exceptions.ValidationError as err:
90        # Print onto stdout and stderr.
91        print("Error: Failed to validate data file: {} using schema: {}."
92              "\n Exception Message: \"{}\""
93              " ".format(driverjson_data, _schema, str(err)))
94        print("Error: Failed to validate data file: {} using schema: {}."
95              "\n Exception Message: \"{}\""
96              " ".format(driverjson_data, _schema, str(err)), file=sys.stderr)
97        raise JsonValidationException() from err
98
99
100def load_driver(schemas: Dict[str, Any], driver_file: str) -> Any:
101    """loads validated json driver"""
102    with open(file=driver_file, mode='r', encoding='UTF-8') as f:
103        json_data = json.load(f)
104        try:
105            validate_json(json_data, schemas)
106        except JsonValidationException as e:
107            raise DriverReaderException from e
108        return json_data
109
110
111def load_schemas(mbedtls_root: str) -> Dict[str, Any]:
112    """
113    Load schemas map
114    """
115    schema_file_paths = {
116        'transparent': os.path.join(mbedtls_root,
117                                    'scripts',
118                                    'data_files',
119                                    'driver_jsons',
120                                    'driver_transparent_schema.json'),
121        'opaque': os.path.join(mbedtls_root,
122                               'scripts',
123                               'data_files',
124                               'driver_jsons',
125                               'driver_opaque_schema.json')
126    }
127    driver_schema = {}
128    for key, file_path in schema_file_paths.items():
129        with open(file=file_path, mode='r', encoding='UTF-8') as file:
130            driver_schema[key] = json.load(file)
131    return driver_schema
132
133
134def read_driver_descriptions(mbedtls_root: str,
135                             json_directory: str,
136                             jsondriver_list: str) -> list:
137    """
138    Merge driver JSON files into a single ordered JSON after validation.
139    """
140    driver_schema = load_schemas(mbedtls_root)
141
142    with open(file=os.path.join(json_directory, jsondriver_list),
143              mode='r',
144              encoding='UTF-8') as driver_list_file:
145        driver_list = json.load(driver_list_file)
146
147    return [load_driver(schemas=driver_schema,
148                        driver_file=os.path.join(json_directory, driver_file_name))
149            for driver_file_name in driver_list]
150
151
152def trace_exception(e: Exception, file=sys.stderr) -> None:
153    """Prints exception trace to the given TextIO handle"""
154    print("Exception: type: %s, message: %s, trace: %s" % (
155        e.__class__, str(e), format_tb(e.__traceback__)
156    ), file)
157
158
159TEMPLATE_FILENAMES = ["psa_crypto_driver_wrappers.h.jinja",
160                      "psa_crypto_driver_wrappers_no_static.c.jinja"]
161
162def main() -> int:
163    """
164    Main with command line arguments.
165    """
166    def_arg_mbedtls_root = build_tree.guess_mbedtls_root()
167
168    parser = argparse.ArgumentParser()
169    parser.add_argument('--mbedtls-root', default=def_arg_mbedtls_root,
170                        help='root directory of mbedtls source code')
171    parser.add_argument('--template-dir',
172                        help='directory holding the driver templates')
173    parser.add_argument('--json-dir',
174                        help='directory holding the driver JSONs')
175    parser.add_argument('output_directory', nargs='?',
176                        help='output file\'s location')
177    args = parser.parse_args()
178
179    mbedtls_root = os.path.abspath(args.mbedtls_root)
180
181    output_directory = args.output_directory if args.output_directory is not None else \
182        os.path.join(mbedtls_root, 'library')
183    template_directory = args.template_dir if args.template_dir is not None else \
184        os.path.join(mbedtls_root,
185                     'scripts',
186                     'data_files',
187                     'driver_templates')
188    json_directory = args.json_dir if args.json_dir is not None else \
189        os.path.join(mbedtls_root,
190                     'scripts',
191                     'data_files',
192                     'driver_jsons')
193
194    try:
195        # Read and validate list of driver jsons from driverlist.json
196        merged_driver_json = read_driver_descriptions(mbedtls_root,
197                                                      json_directory,
198                                                      'driverlist.json')
199    except DriverReaderException as e:
200        trace_exception(e)
201        return 1
202    for template_filename in TEMPLATE_FILENAMES:
203        generate_driver_wrapper_file(template_directory, output_directory,
204                                     template_filename, merged_driver_json)
205    return 0
206
207
208if __name__ == '__main__':
209    sys.exit(main())
210