1#! /usr/bin/env perl
2
3# Generate query_config.c
4#
5# The file query_config.c contains a C function that can be used to check if
6# a configuration macro is defined and to retrieve its expansion in string
7# form (if any). This facilitates querying the compile time configuration of
8# the library, for example, for testing.
9#
10# The query_config.c is generated from the current configuration at
11# include/mbedtls/mbedtls_config.h. The idea is that the mbedtls_config.h contains ALL the
12# compile time configurations available in Mbed TLS (commented or uncommented).
13# This script extracts the configuration macros from the mbedtls_config.h and this
14# information is used to automatically generate the body of the query_config()
15# function by using the template in scripts/data_files/query_config.fmt.
16#
17# Usage: scripts/generate_query_config.pl without arguments, or
18# generate_query_config.pl config_file template_file output_file
19#
20# Copyright The Mbed TLS Contributors
21# SPDX-License-Identifier: Apache-2.0
22#
23# Licensed under the Apache License, Version 2.0 (the "License"); you may
24# not use this file except in compliance with the License.
25# You may obtain a copy of the License at
26#
27# http://www.apache.org/licenses/LICENSE-2.0
28#
29# Unless required by applicable law or agreed to in writing, software
30# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
31# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
32# See the License for the specific language governing permissions and
33# limitations under the License.
34
35use strict;
36
37my ($config_file, $query_config_format_file, $query_config_file);
38
39if( @ARGV ) {
40    die "Invalid number of arguments - usage: $0 [CONFIG_FILE TEMPLATE_FILE OUTPUT_FILE]" if scalar @ARGV != 3;
41    ($config_file, $query_config_format_file, $query_config_file) = @ARGV;
42
43    -f $config_file or die "No such file: $config_file";
44    -f $query_config_format_file or die "No such file: $query_config_format_file";
45} else {
46    $config_file = "./include/mbedtls/mbedtls_config.h";
47    $query_config_format_file = "./scripts/data_files/query_config.fmt";
48    $query_config_file = "./programs/test/query_config.c";
49
50    unless( -f $config_file && -f $query_config_format_file ) {
51        chdir '..' or die;
52        -f $config_file && -f $query_config_format_file
53          or die "No arguments supplied, must be run from project root or a first-level subdirectory\n";
54    }
55}
56
57# Excluded macros from the generated query_config.c. For example, macros that
58# have commas or function-like macros cannot be transformed into strings easily
59# using the preprocessor, so they should be excluded or the preprocessor will
60# throw errors.
61my @excluded = qw(
62MBEDTLS_SSL_CIPHERSUITES
63);
64my $excluded_re = join '|', @excluded;
65
66open(CONFIG_FILE, "$config_file") or die "Opening config file '$config_file': $!";
67
68# This variable will contain the string to replace in the CHECK_CONFIG of the
69# format file
70my $config_check = "";
71
72while (my $line = <CONFIG_FILE>) {
73    if ($line =~ /^(\/\/)?\s*#\s*define\s+(MBEDTLS_\w+).*/) {
74        my $name = $2;
75
76        # Skip over the macro if it is in the ecluded list
77        next if $name =~ /$excluded_re/;
78
79        $config_check .= "#if defined($name)\n";
80        $config_check .= "    if( strcmp( \"$name\", config ) == 0 )\n";
81        $config_check .= "    {\n";
82        $config_check .= "        MACRO_EXPANSION_TO_STR( $name );\n";
83        $config_check .= "        return( 0 );\n";
84        $config_check .= "    }\n";
85        $config_check .= "#endif /* $name */\n";
86        $config_check .= "\n";
87    }
88}
89
90# Read the full format file into a string
91local $/;
92open(FORMAT_FILE, "$query_config_format_file") or die "Opening query config format file '$query_config_format_file': $!";
93my $query_config_format = <FORMAT_FILE>;
94close(FORMAT_FILE);
95
96# Replace the body of the query_config() function with the code we just wrote
97$query_config_format =~ s/CHECK_CONFIG/$config_check/g;
98
99# Rewrite the query_config.c file
100open(QUERY_CONFIG_FILE, ">$query_config_file") or die "Opening destination file '$query_config_file': $!";
101print QUERY_CONFIG_FILE $query_config_format;
102close(QUERY_CONFIG_FILE);
103