Squashed 'lib/mbedtls/external/mbedtls/' content from commit 2ca6c285a0dd

git-subtree-dir: lib/mbedtls/external/mbedtls
git-subtree-split: 2ca6c285a0dd3f33982dd57299012dacab1ff206

1 files changed, 162 insertions, 0 deletions

diff --git a/scripts/mbedtls_dev/c_build_helper.py b/scripts/mbedtls_dev/c_build_helper.py
new file mode 100644
index 00000000000..f2cbbe4af7e
--- /dev/null
+++ b/scripts/mbedtls_dev/c_build_helper.py
@@ -0,0 +1,162 @@
+"""Generate and run C code.
+"""
+
+# Copyright The Mbed TLS Contributors
+# SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+#
+
+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 compile_c_file(c_filename, exe_filename, include_dirs):
+    """Compile a C source file with the host compiler.
+
+    * ``c_filename``: the name of the source file to compile.
+    * ``exe_filename``: the name for the executable to be created.
+    * ``include_dirs``: a list of paths to include directories to be passed
+      with the -I switch.
+    """
+    # Respect $HOSTCC if it is set
+    cc = os.getenv('HOSTCC', None)
+    if cc is None:
+        cc = os.getenv('CC', 'cc')
+    cmd = [cc]
+
+    proc = subprocess.Popen(cmd,
+                            stdout=subprocess.DEVNULL,
+                            stderr=subprocess.PIPE,
+                            universal_newlines=True)
+    cc_is_msvc = 'Microsoft (R) C/C++' in proc.communicate()[1]
+
+    cmd += ['-I' + dir for dir in include_dirs]
+    if cc_is_msvc:
+        # MSVC has deprecated using -o to specify the output file,
+        # and produces an object file in the working directory by default.
+        obj_filename = exe_filename[:-4] + '.obj'
+        cmd += ['-Fe' + exe_filename, '-Fo' + obj_filename]
+    else:
+        cmd += ['-o' + exe_filename]
+
+    subprocess.check_call(cmd + [c_filename])
+
+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, too-many-locals
+    """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).
+
+    Use the C compiler specified by the ``CC`` environment variable, defaulting
+    to ``cc``. If ``CC`` looks like MSVC, use its command line syntax,
+    otherwise assume the compiler supports Unix traditional ``-I`` and ``-o``.
+
+    Return the list of values of the ``expressions``.
+    """
+    if include_path is None:
+        include_path = []
+    c_name = None
+    exe_name = None
+    obj_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()
+
+        compile_c_file(c_name, exe_name, include_path)
+        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)
+        remove_file_if_exists(obj_name)