mbedtls/scripts/generate_errors.pl
Gaurav Aggarwal a9f64006ea Add support for const error description strings
Problem
-------
mbedtls_strerror is a utility function which converts an mbedTLS error code
into a human readable string. It requires the caller to allocate a buffer every
time an error code needs to be converted to a string. It is an overkill and a
waste of RAM for resource constrained microcontrollers - where the most common
use case is to use these strings for logging.

Solution
--------
The proposed commit adds two functions:

* const char * mbedtls_high_level_strerr( int error_code );
* const char * mbedtls_low_level_strerr( int error_code );

The above two functions convert the high level and low level parts of an mbedTLS
error code to human readable strings. They return a const pointer to an
unmodifiable string which is not supposed to be modified by the caller and only
to be used for logging purposes. The caller no longer needs to allocate a
buffer.

Backward Compatibility
----------------------
The proposed change is completely backward compatible as it does not change
the existing mbedtls_strerror function and ensures that it continues to behave
the same way.

Signed-off-by: Gaurav Aggarwal <aggarg@amazon.com>
2020-04-09 01:44:52 -07:00

196 lines
5.7 KiB
Perl
Executable File

#!/usr/bin/env perl
# Generate error.c
#
# Usage: ./generate_errors.pl or scripts/generate_errors.pl without arguments,
# or generate_errors.pl include_dir data_dir error_file
use strict;
my ($include_dir, $data_dir, $error_file);
if( @ARGV ) {
die "Invalid number of arguments" if scalar @ARGV != 3;
($include_dir, $data_dir, $error_file) = @ARGV;
-d $include_dir or die "No such directory: $include_dir\n";
-d $data_dir or die "No such directory: $data_dir\n";
} else {
$include_dir = 'include/mbedtls';
$data_dir = 'scripts/data_files';
$error_file = 'library/error.c';
unless( -d $include_dir && -d $data_dir ) {
chdir '..' or die;
-d $include_dir && -d $data_dir
or die "Without arguments, must be run from root or scripts\n"
}
}
my $error_format_file = $data_dir.'/error.fmt';
my @low_level_modules = qw( AES ARC4 ARIA ASN1 BASE64 BIGNUM BLOWFISH
CAMELLIA CCM CHACHA20 CHACHAPOLY CMAC CTR_DRBG DES
ENTROPY ERROR GCM HKDF HMAC_DRBG MD2 MD4 MD5
NET OID PADLOCK PBKDF2 PLATFORM POLY1305 RIPEMD160
SHA1 SHA256 SHA512 THREADING XTEA );
my @high_level_modules = qw( CIPHER DHM ECP MD
PEM PK PKCS12 PKCS5
RSA SSL X509 );
my $line_separator = $/;
undef $/;
open(FORMAT_FILE, "$error_format_file") or die "Opening error format file '$error_format_file': $!";
my $error_format = <FORMAT_FILE>;
close(FORMAT_FILE);
$/ = $line_separator;
my @files = <$include_dir/*.h>;
my @matches;
foreach my $file (@files) {
open(FILE, "$file");
my @grep_res = grep(/^\s*#define\s+MBEDTLS_ERR_\w+\s+\-0x[0-9A-Fa-f]+/, <FILE>);
push(@matches, @grep_res);
close FILE;
}
my $ll_old_define = "";
my $hl_old_define = "";
my $ll_code_check = "";
my $hl_code_check = "";
my $headers = "";
my %error_codes_seen;
foreach my $line (@matches)
{
next if ($line =~ /compat-1.2.h/);
my ($error_name, $error_code) = $line =~ /(MBEDTLS_ERR_\w+)\s+\-(0x\w+)/;
my ($description) = $line =~ /\/\*\*< (.*?)\.? \*\//;
die "Duplicated error code: $error_code ($error_name)\n"
if( $error_codes_seen{$error_code}++ );
$description =~ s/\\/\\\\/g;
if ($description eq "") {
$description = "DESCRIPTION MISSING";
warn "Missing description for $error_name\n";
}
my ($module_name) = $error_name =~ /^MBEDTLS_ERR_([^_]+)/;
# Fix faulty ones
$module_name = "BIGNUM" if ($module_name eq "MPI");
$module_name = "CTR_DRBG" if ($module_name eq "CTR");
$module_name = "HMAC_DRBG" if ($module_name eq "HMAC");
my $define_name = $module_name;
$define_name = "X509_USE,X509_CREATE" if ($define_name eq "X509");
$define_name = "ASN1_PARSE" if ($define_name eq "ASN1");
$define_name = "SSL_TLS" if ($define_name eq "SSL");
$define_name = "PEM_PARSE,PEM_WRITE" if ($define_name eq "PEM");
my $include_name = $module_name;
$include_name =~ tr/A-Z/a-z/;
$include_name = "" if ($include_name eq "asn1");
# Fix faulty ones
$include_name = "net_sockets" if ($module_name eq "NET");
my $found_ll = grep $_ eq $module_name, @low_level_modules;
my $found_hl = grep $_ eq $module_name, @high_level_modules;
if (!$found_ll && !$found_hl)
{
printf("Error: Do not know how to handle: $module_name\n");
exit 1;
}
my $code_check;
my $old_define;
my $white_space;
my $first;
if ($found_ll)
{
$code_check = \$ll_code_check;
$old_define = \$ll_old_define;
$white_space = ' ';
}
else
{
$code_check = \$hl_code_check;
$old_define = \$hl_old_define;
$white_space = ' ';
}
if ($define_name ne ${$old_define})
{
if (${$old_define} ne "")
{
${$code_check} .= "#endif /* ";
$first = 0;
foreach my $dep (split(/,/, ${$old_define}))
{
${$code_check} .= " || " if ($first++);
${$code_check} .= "MBEDTLS_${dep}_C";
}
${$code_check} .= " */\n\n";
}
${$code_check} .= "#if ";
$headers .= "#if " if ($include_name ne "");
$first = 0;
foreach my $dep (split(/,/, ${define_name}))
{
${$code_check} .= " || " if ($first);
$headers .= " || " if ($first++);
${$code_check} .= "defined(MBEDTLS_${dep}_C)";
$headers .= "defined(MBEDTLS_${dep}_C)" if
($include_name ne "");
}
${$code_check} .= "\n";
$headers .= "\n#include \"mbedtls/${include_name}.h\"\n".
"#endif\n\n" if ($include_name ne "");
${$old_define} = $define_name;
}
${$code_check} .= "${white_space}\{.code = -($error_name), .description=\"$module_name - $description\"},\n";
};
if ($ll_old_define ne "")
{
$ll_code_check .= "#endif /* ";
my $first = 0;
foreach my $dep (split(/,/, $ll_old_define))
{
$ll_code_check .= " || " if ($first++);
$ll_code_check .= "MBEDTLS_${dep}_C";
}
$ll_code_check .= " */\n";
}
if ($hl_old_define ne "")
{
$hl_code_check .= "#endif /* ";
my $first = 0;
foreach my $dep (split(/,/, $hl_old_define))
{
$hl_code_check .= " || " if ($first++);
$hl_code_check .= "MBEDTLS_${dep}_C";
}
$hl_code_check .= " */\n";
}
$error_format =~ s/HEADER_INCLUDED\n/$headers/g;
$error_format =~ s/LOW_LEVEL_CODE_CHECKS\n/$ll_code_check/g;
$error_format =~ s/HIGH_LEVEL_CODE_CHECKS\n/$hl_code_check/g;
open(ERROR_FILE, ">$error_file") or die "Opening destination file '$error_file': $!";
print ERROR_FILE $error_format;
close(ERROR_FILE);