aboutsummaryrefslogtreecommitdiff
path: root/lib/mbedtls-2.27.0/scripts/mbedtls_dev/c_build_helper.py
blob: 5c587a16bb60be3ef980b116caf72999293b4b6e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
"""Generate and run C code.
"""

# Copyright The Mbed TLS Contributors
# 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.

import os
import platform
import subprocess
import sys
import tempfile

def remove_file_if_exists(filename):
    """Remove the specified file, ignoring errors."""
    if not filename:
        return
    try:
        os.remove(filename)
    except OSError:
        pass

def create_c_file(file_label):
    """Create a temporary C file.

    * ``file_label``: a string that will be included in the file name.

    Return ```(c_file, c_name, exe_name)``` where ``c_file`` is a Python
    stream open for writing to the file, ``c_name`` is the name of the file
    and ``exe_name`` is the name of the executable that will be produced
    by compiling the file.
    """
    c_fd, c_name = tempfile.mkstemp(prefix='tmp-{}-'.format(file_label),
                                    suffix='.c')
    exe_suffix = '.exe' if platform.system() == 'Windows' else ''
    exe_name = c_name[:-2] + exe_suffix
    remove_file_if_exists(exe_name)
    c_file = os.fdopen(c_fd, 'w', encoding='ascii')
    return c_file, c_name, exe_name

def generate_c_printf_expressions(c_file, cast_to, printf_format, expressions):
    """Generate C instructions to print the value of ``expressions``.

    Write the code with ``c_file``'s ``write`` method.

    Each expression is cast to the type ``cast_to`` and printed with the
    printf format ``printf_format``.
    """
    for expr in expressions:
        c_file.write('    printf("{}\\n", ({}) {});\n'
                     .format(printf_format, cast_to, expr))

def generate_c_file(c_file,
                    caller, header,
                    main_generator):
    """Generate a temporary C source file.

    * ``c_file`` is an open stream on the C source file.
    * ``caller``: an informational string written in a comment at the top
      of the file.
    * ``header``: extra code to insert before any function in the generated
      C file.
    * ``main_generator``: a function called with ``c_file`` as its sole argument
      to generate the body of the ``main()`` function.
    """
    c_file.write('/* Generated by {} */'
                 .format(caller))
    c_file.write('''
#include <stdio.h>
''')
    c_file.write(header)
    c_file.write('''
int main(void)
{
''')
    main_generator(c_file)
    c_file.write('''    return 0;
}
''')

def get_c_expression_values(
        cast_to, printf_format,
        expressions,
        caller=__name__, file_label='',
        header='', include_path=None,
        keep_c=False,
): # pylint: disable=too-many-arguments
    """Generate and run a program to print out numerical values for expressions.

    * ``cast_to``: a C type.
    * ``printf_format``: a printf format suitable for the type ``cast_to``.
    * ``header``: extra code to insert before any function in the generated
      C file.
    * ``expressions``: a list of C language expressions that have the type
      ``cast_to``.
    * ``include_path``: a list of directories containing header files.
    * ``keep_c``: if true, keep the temporary C file (presumably for debugging
      purposes).

    Return the list of values of the ``expressions``.
    """
    if include_path is None:
        include_path = []
    c_name = None
    exe_name = None
    try:
        c_file, c_name, exe_name = create_c_file(file_label)
        generate_c_file(
            c_file, caller, header,
            lambda c_file: generate_c_printf_expressions(c_file,
                                                         cast_to, printf_format,
                                                         expressions)
        )
        c_file.close()
        cc = os.getenv('CC', 'cc')
        subprocess.check_call([cc] +
                              ['-I' + dir for dir in include_path] +
                              ['-o', exe_name, c_name])
        if keep_c:
            sys.stderr.write('List of {} tests kept at {}\n'
                             .format(caller, c_name))
        else:
            os.remove(c_name)
        output = subprocess.check_output([exe_name])
        return output.decode('ascii').strip().split('\n')
    finally:
        remove_file_if_exists(exe_name)