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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 
35 use strict;
36 
37 my ($config_file, $query_config_format_file, $query_config_file);
38 
39 if( @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.
61 my @excluded = qw(
62 MBEDTLS_SSL_CIPHERSUITES
63 );
64 my $excluded_re = join '|', @excluded;
65 
66 open(CONFIG_FILE, "$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
70 my $config_check = "";
71 my $list_config = "";
72 
73 while (my $line = <CONFIG_FILE>) {
74     if ($line =~ /^(\/\/)?\s*#\s*define\s+(MBEDTLS_\w+).*/) {
75         my $name = $2;
76 
77         # Skip over the macro if it is in the ecluded list
78         next if $name =~ /$excluded_re/;
79 
80         $config_check .= "#if defined($name)\n";
81         $config_check .= "    if( strcmp( \"$name\", config ) == 0 )\n";
82         $config_check .= "    {\n";
83         $config_check .= "        MACRO_EXPANSION_TO_STR( $name );\n";
84         $config_check .= "        return( 0 );\n";
85         $config_check .= "    }\n";
86         $config_check .= "#endif /* $name */\n";
87         $config_check .= "\n";
88 
89         $list_config .= "#if defined($name)\n";
90         $list_config .= "    OUTPUT_MACRO_NAME_VALUE($name);\n";
91         $list_config .= "#endif /* $name */\n";
92         $list_config .= "\n";
93     }
94 }
95 
96 # Read the full format file into a string
97 local $/;
98 open(FORMAT_FILE, "$query_config_format_file") or die "Opening query config format file '$query_config_format_file': $!";
99 my $query_config_format = <FORMAT_FILE>;
100 close(FORMAT_FILE);
101 
102 # Replace the body of the query_config() function with the code we just wrote
103 $query_config_format =~ s/CHECK_CONFIG/$config_check/g;
104 $query_config_format =~ s/LIST_CONFIG/$list_config/g;
105 
106 # Rewrite the query_config.c file
107 open(QUERY_CONFIG_FILE, ">$query_config_file") or die "Opening destination file '$query_config_file': $!";
108 print QUERY_CONFIG_FILE $query_config_format;
109 close(QUERY_CONFIG_FILE);
110