3 # Build log hardening check, checks build logs for missing hardening flags.
5 # Copyright (C) 2012 Simon Ruderich
7 # This program is free software: you can redistribute it and/or modify
8 # it under the terms of the GNU General Public License as published by
9 # the Free Software Foundation, either version 3 of the License, or
10 # (at your option) any later version.
12 # This program is distributed in the hope that it will be useful,
13 # but WITHOUT ANY WARRANTY; without even the implied warranty of
14 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 # GNU General Public License for more details.
17 # You should have received a copy of the GNU General Public License
18 # along with this program. If not, see <http://www.gnu.org/licenses/>.
25 use Term::ANSIColor ();
26 use Text::ParseWords ();
28 our $VERSION = '0.01';
33 # Regex to catch compiler commands.
35 (?<!\.)(?:cc|gcc|g\+\+|c\+\+)
38 # Full regex which matches the complete compiler name. Used in a few places to
39 # prevent false negatives.
40 my $cc_regex_full = qr/
41 (?:[a-z0-9_]+-(?:linux-|kfreebsd-)?gnu(?:eabi|eabihf)?-)?
44 # Regex to catch (GCC) compiler warnings.
45 my $warning_regex = qr/^(.+?):([0-9]+):[0-9]+: warning: (.+?) \[(.+?)\]$/;
47 # List of source file extensions which require preprocessing.
48 my @source_preprocess_compile_cpp = (
50 qw( cc cp cxx cpp CPP c++ C ),
54 my @source_preprocess_compile = (
60 @source_preprocess_compile_cpp,
62 qw( F FOR fpp FPP FTN F90 F95 F03 F08 ),
64 my @source_preprocess_no_compile = (
68 my @source_preprocess = (
69 @source_preprocess_compile,
70 @source_preprocess_no_compile,
72 # List of source file extensions which don't require preprocessing.
73 my @source_no_preprocess_compile_cpp = (
79 my @source_no_preprocess_compile = (
83 @source_no_preprocess_compile_cpp,
87 qw( f for ftn f90 f95 f03 f08 ),
89 my @source_no_preprocess_no_compile = (
93 my @source_no_preprocess = (
94 @source_no_preprocess_compile,
95 @source_no_preprocess_no_compile,
97 # List of header file extensions which require preprocessing.
98 my @header_preprocess = (
99 # C, C++, Objective-C, Objective-C++
102 qw( hh H hp hxx hpp HPP h++ tcc ),
105 # Hashes for fast extensions lookup to check if a file falls in one of these
107 my %extensions_no_preprocess = map { $_ => 1 } (
108 @source_no_preprocess,
110 my %extensions_preprocess = map { $_ => 1 } (
114 my %extensions_compile_link = map { $_ => 1 } (
116 @source_no_preprocess,
118 my %extensions_compile = map { $_ => 1 } (
119 @source_preprocess_compile,
120 @source_no_preprocess_compile,
122 my %extensions_no_compile = map { $_ => 1 } (
123 @source_preprocess_no_compile,
124 @source_no_preprocess_no_compile,
126 my %extensions_compile_cpp = map { $_ => 1 } (
127 @source_preprocess_compile_cpp,
128 @source_no_preprocess_compile_cpp,
130 my %extension = map { $_ => 1 } (
131 @source_no_preprocess,
132 @source_no_preprocess_compile,
133 @source_no_preprocess_compile_cpp,
134 @source_no_preprocess_no_compile,
137 @source_preprocess_compile,
138 @source_preprocess_compile_cpp,
139 @source_preprocess_no_compile,
142 # Regexp to match file extensions.
143 my $file_extension_regex = qr/
145 \S+ # Filename without extension.
147 ([^\\.,;:\s]+) # File extension.
148 (?=\s|\\) # At end of word. Can't use \b because some files have non
149 # word characters at the end and because \b matches double
150 # extensions (like .cpp.o). Works always as all lines are
151 # terminated with "\n".
154 # Expected (hardening) flags. All flags are used as regexps.
159 my @def_cflags_format = (
162 '-Werror=format-security',
164 my @def_cflags_fortify = (
165 # fortify needs at least -O1, but -O2 is recommended anyway
167 my @def_cflags_stack = (
169 '--param=ssp-buffer-size=4',
171 my @def_cflags_pie = (
177 # @def_cxxflags_* is the same as @def_cflags_*.
178 my @def_cppflags = ();
179 my @def_cppflags_fortify = (
180 '-D_FORTIFY_SOURCE=2',
182 my @def_ldflags = ();
183 my @def_ldflags_relro = (
186 my @def_ldflags_bindnow = (
189 my @def_ldflags_pie = (
193 my @def_ldflags_pic = (
198 # Renaming rules for the output so the regex parts are not visible. Also
199 # stores string values of flag regexps above, see compile_flag_regexp().
201 '-O(?:2|3)' => '-O2',
202 '-Wl,(-z,)?relro' => '-Wl,-z,relro',
203 '-Wl,(-z,)?now' => '-Wl,-z,now',
206 # Statistics of missing flags and non-verbose build commands. Used for
210 preprocess_missing => 0,
212 compile_missing => 0,
214 compile_cpp_missing => 0,
218 commands_nonverbose => 0,
221 # Use colored (ANSI) output?
228 my ($message, $missing_flags_ref, $flag_renames_ref, $line) = @_;
230 # Get string value of qr//-escaped regexps and if requested rename them.
231 my @missing_flags = map {
232 $flag_renames_ref->{$_}
233 } @{$missing_flags_ref};
235 my $flags = join ' ', @missing_flags;
236 printf "%s (%s)%s %s",
237 error_color($message, 'red'), $flags, error_color(':', 'yellow'),
240 sub error_non_verbose_build {
244 error_color('NONVERBOSE BUILD', 'red'),
245 error_color(':', 'yellow'),
248 sub error_hardening_wrapper {
250 error_color('HARDENING WRAPPER', 'red'),
251 error_color(':', 'yellow'),
252 'no checks possible, aborting';
255 my ($message, $color) = @_;
258 return Term::ANSIColor::colored($message, $color);
265 my ($line, @flags) = @_;
267 foreach my $flag (@flags) {
268 return 1 if $line =~ /$flag/;
274 my ($line, $missing_flags_ref, @flags) = @_;
276 my @missing_flags = ();
277 foreach my $flag (@flags) {
278 if (not $line =~ /$flag/) {
279 push @missing_flags, $flag;
283 return 1 if scalar @missing_flags == 0;
285 @{$missing_flags_ref} = @missing_flags;
289 # Modifies $missing_flags_ref array.
290 sub pic_pie_conflict {
291 my ($line, $pie, $missing_flags_ref, @flags_pie) = @_;
293 return 0 if not $pie;
294 return 0 if not any_flags_used($line, @def_ldflags_pic);
296 my %flags = map { $_ => 1 } @flags_pie;
298 # Remove all PIE flags from @missing_flags as they are not required with
301 not exists $flags{$_}
302 } @{$missing_flags_ref};
303 @{$missing_flags_ref} = @result;
305 # We got a conflict when no flags are left, thus only PIE flags were
306 # missing. If other flags were missing abort because the conflict is not
308 return scalar @result == 0;
311 sub is_non_verbose_build {
312 my ($line, $next_line, $skip_ref) = @_;
314 if (not ($line =~ /^checking if you want to see long compiling messages\.\.\. no/
315 or $line =~ /^\s*\[?(?:CC|CCLD|CXX|CXXLD|LD|LINK)\]?\s+(.+?)$/
316 or $line =~ /^\s*(?:C|c)ompiling\s+(.+?)(?:\.\.\.)?$/
317 or $line =~ /^\s*(?:B|b)uilding (?:program|shared library)\s+(.+?)$/
318 or $line =~ /^\s*\[[\d ]+%\] Building (?:C|CXX) object (.+?)$/)) {
324 # On the first pass we only check if this line is verbose or not.
325 return 1 if not defined $next_line;
327 # Second pass, we have access to the next line.
330 # CMake and other build systems print the non-verbose messages also when
331 # building verbose. If a compiler and the file name occurs in the next
332 # line, treat it as verbose build.
334 # Get filename, we can't use the complete path as only parts of it are
335 # used in the real compiler command.
336 $file =~ m{/([^/\s]+)$};
339 if ($next_line =~ /\Q$file\E/ and $next_line =~ /$cc_regex/o) {
340 # We still have to skip the current line as it doesn't contain any
350 sub compile_flag_regexp {
351 my ($flag_renames_ref, @flags) = @_;
354 foreach my $flag (@flags) {
355 # Store flag name in replacement string for correct flags in messages
356 # with qr//ed flag regexps.
357 $flag_renames_ref->{qr/\s$flag(?:\s|\\)/}
358 = (exists $flag_renames_ref->{$flag})
359 ? $flag_renames_ref->{$flag}
362 # Compile flag regexp for faster execution.
363 push @result, qr/\s$flag(?:\s|\\)/;
368 sub extension_found {
369 my ($extensions_ref, @extensions) = @_;
372 foreach my $extension (@extensions) {
373 if (exists $extensions_ref->{$extension}) {
384 # Parse command line arguments.
386 my $option_version = 0;
388 my $option_bindnow = 0;
390 my $option_arch = undef;
391 my $option_buildd = 0;
393 if (not Getopt::Long::GetOptions(
394 'help|h|?' => \$option_help,
395 'version' => \$option_version,
397 'pie' => \$option_pie,
398 'bindnow' => \$option_bindnow,
399 'all' => \$option_all,
401 'color' => \$option_color,
402 'arch=s' => \$option_arch,
403 'buildd' => \$option_buildd,
406 Pod::Usage::pod2usage(2);
410 Pod::Usage::pod2usage(1);
412 if ($option_version) {
413 print "blhc $VERSION Copyright (C) 2012 Simon Ruderich
415 This program is free software: you can redistribute it and/or modify
416 it under the terms of the GNU General Public License as published by
417 the Free Software Foundation, either version 3 of the License, or
418 (at your option) any later version.
420 This program is distributed in the hope that it will be useful,
421 but WITHOUT ANY WARRANTY; without even the implied warranty of
422 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
423 GNU General Public License for more details.
425 You should have received a copy of the GNU General Public License
426 along with this program. If not, see <http://www.gnu.org/licenses/>.
436 # Precompile all flag regexps. any_flags_used(), all_flags_used() get a lot
438 @def_cflags = compile_flag_regexp(\%flag_renames, @def_cflags);
439 @def_cflags_format = compile_flag_regexp(\%flag_renames, @def_cflags_format);
440 @def_cflags_fortify = compile_flag_regexp(\%flag_renames, @def_cflags_fortify);
441 @def_cflags_stack = compile_flag_regexp(\%flag_renames, @def_cflags_stack);
442 @def_cflags_pie = compile_flag_regexp(\%flag_renames, @def_cflags_pie);
443 @def_cxxflags = compile_flag_regexp(\%flag_renames, @def_cxxflags);
444 @def_cppflags = compile_flag_regexp(\%flag_renames, @def_cppflags);
445 @def_cppflags_fortify = compile_flag_regexp(\%flag_renames, @def_cppflags_fortify);
446 @def_ldflags = compile_flag_regexp(\%flag_renames, @def_ldflags);
447 @def_ldflags_relro = compile_flag_regexp(\%flag_renames, @def_ldflags_relro);
448 @def_ldflags_bindnow = compile_flag_regexp(\%flag_renames, @def_ldflags_bindnow);
449 @def_ldflags_pie = compile_flag_regexp(\%flag_renames, @def_ldflags_pie);
450 @def_ldflags_pic = compile_flag_regexp(\%flag_renames, @def_ldflags_pic);
455 FILE: foreach my $file (@ARGV) {
456 open my $fh, '<', $file or die "$!: $file";
458 # Hardening options. Not all architectures support all hardening options.
459 my $harden_format = 1;
460 my $harden_fortify = 1;
461 my $harden_stack = 1;
462 my $harden_relro = 1;
463 my $harden_bindnow = $option_bindnow; # defaults to 0
464 my $harden_pie = $option_pie; # defaults to 0
466 while (my $line = <$fh>) {
467 # dpkg-buildflags only provides hardening flags since 1.16.1, don't
468 # check for hardening flags in buildd mode if an older dpkg-dev is
469 # used. Default flags (-g -O2) are still checked.
471 # Packages which were built before 1.16.1 but used their own hardening
472 # flags are not checked.
473 if ($option_buildd and $line =~ /^Toolchain package versions: /) {
474 require Dpkg::Version;
475 if ($line !~ /dpkg-dev_(\S+)/
476 or Dpkg::Version::version_compare($1, '1.16.1') < 0) {
486 # If hardening wrapper is used (wraps calls to gcc and adds hardening
487 # flags automatically) we can't perform any checks, abort.
488 if ($line =~ /^Build-Depends: .*\bhardening-wrapper\b/) {
489 if (not $option_buildd) {
490 error_hardening_wrapper();
492 print "I-hardening-wrapper-used\n";
498 # We skip over unimportant lines at the beginning of the log to
499 # prevent false positives.
500 last if $line =~ /^dpkg-buildpackage:/;
503 # Input lines, contain only the lines with compiler commands.
506 my $continuation = 0;
507 my $complete_line = undef;
508 while (my $line = <$fh>) {
509 # And stop at the end of the build log. Package details (reported by
510 # the buildd logs) are not important for us. This also prevents false
512 last if $line =~ /^Build finished at \d{8}-\d{4}$/;
514 # Detect architecture automatically unless overridden.
516 and $line =~ /^dpkg-buildpackage: host architecture (.+)$/) {
520 # Ignore compiler warnings for now.
521 next if $line =~ /$warning_regex/o;
523 if ($line =~ /\033/) { # esc
524 # Remove all ANSI color sequences which are sometimes used in
525 # non-verbose builds.
526 $line = Term::ANSIColor::colorstrip($line);
527 # Also strip '\0xf' (delete previous character), used by Elinks'
530 # And "ESC(B" which seems to be used on armhf and hurd (not sure
532 $line =~ s/\033\(B//g;
535 # Check if this line indicates a non verbose build.
536 my $non_verbose = is_non_verbose_build($line);
538 # One line may contain multiple commands (";"). Treat each one as
539 # single line. parse_line() is slow, only use it when necessary.
540 my @line = (not $line =~ /;/)
543 # Ensure newline at the line end - necessary for
544 # correct parsing later.
547 } Text::ParseWords::parse_line(';', 1, $line);
548 foreach $line (@line) {
552 # Join lines, but leave the "\" in place so it's clear where
553 # the original line break was.
554 chomp $complete_line;
555 $complete_line .= ' ' . $line;
557 # Line continuation, line ends with "\".
558 if ($line =~ /\\\s*$/) {
560 # Start line continuation.
561 if (not defined $complete_line) {
562 $complete_line = $line;
567 if (not $continuation) {
568 # Use the complete line if a line continuation occurred.
569 if (defined $complete_line) {
570 $line = $complete_line;
571 $complete_line = undef;
574 # Ignore lines with no compiler commands.
575 next if not $non_verbose
576 and not $line =~ /\b$cc_regex(?:\s|\\)/o;
577 # Ignore lines with no filenames with extensions. May miss
578 # some non-verbose builds (e.g. "gcc -o test" [sic!]), but
579 # shouldn't be a problem as the log will most likely contain
580 # other non-verbose commands which are detected.
581 next if not $non_verbose
582 and not $line =~ /$file_extension_regex/o;
584 # Ignore false positives.
586 # `./configure` output.
587 next if not $non_verbose
588 and $line =~ /^(?:checking|(?:C|c)onfigure:) /;
589 next if $line =~ /^\s*(?:- )?(?:HOST_)?(?:CC|CXX)\s*=\s*$cc_regex_full\s*$/o;
591 # Check if additional hardening options were used. Used to
592 # ensure they are used for the complete build.
593 $harden_pie = 1 if any_flags_used($line, @def_cflags_pie, @def_ldflags_pie);
594 $harden_bindnow = 1 if any_flags_used($line, @def_ldflags_bindnow);
603 if (scalar @input == 0) {
604 if (not $option_buildd) {
605 print "No compiler commands!\n";
607 print "W-no-compiler-commands\n";
613 if ($option_buildd) {
614 $statistics{commands} += scalar @input;
617 # Option or auto detected.
619 # The following was partially copied from dpkg-dev 1.16.1.2
620 # (/usr/share/perl5/Dpkg/Vendor/Debian.pm, add_hardening_flags()),
621 # copyright Raphaël Hertzog <hertzog@debian.org>, Kees Cook
622 # <kees@debian.org>, Canonical, Ltd. licensed under GPL version 2 or
623 # later. Keep it in sync.
626 my ($abi, $os, $cpu) = Dpkg::Arch::debarch_to_debtriplet($option_arch);
628 # Disable unsupported hardening options.
629 if ($cpu =~ /^(ia64|alpha|mips|mipsel|hppa)$/ or $option_arch eq 'arm') {
632 if ($cpu =~ /^(ia64|hppa|avr32)$/) {
639 my @cflags = @def_cflags;
640 my @cxxflags = @def_cxxflags;
641 my @cppflags = @def_cppflags;
642 my @ldflags = @def_ldflags;
643 # Check the specified hardening options, same order as dpkg-buildflags.
645 @cflags = (@cflags, @def_cflags_pie);
646 @cxxflags = (@cxxflags, @def_cflags_pie);
647 @ldflags = (@ldflags, @def_ldflags_pie);
650 @cflags = (@cflags, @def_cflags_stack);
651 @cxxflags = (@cxxflags, @def_cflags_stack);
653 if ($harden_fortify) {
654 @cflags = (@cflags, @def_cflags_fortify);
655 @cxxflags = (@cxxflags, @def_cflags_fortify);
656 @cppflags = (@cppflags, @def_cppflags_fortify);
658 if ($harden_format) {
659 @cflags = (@cflags, @def_cflags_format);
660 @cxxflags = (@cxxflags, @def_cflags_format);
663 @ldflags = (@ldflags, @def_ldflags_relro);
665 if ($harden_bindnow) {
666 @ldflags = (@ldflags, @def_ldflags_bindnow);
669 for (my $i = 0; $i < scalar @input; $i++) {
670 my $line = $input[$i];
673 if (is_non_verbose_build($line, $input[$i + 1], \$skip)) {
674 if (not $option_buildd) {
675 error_non_verbose_build($line);
677 $statistics{commands_nonverbose}++;
682 # Even if it's a verbose build, we might have to skip this line.
685 # Remove everything until and including the compiler command. Makes
686 # checks easier and faster.
687 $line =~ s/^.*?$cc_regex//o;
688 # "([...] test.c)" is not detected as 'test.c' - fix this by removing
689 # the brace and similar characters.
690 $line =~ s/['")]+$//;
692 # Skip unnecessary tests when only preprocessing.
693 my $flag_preprocess = 0;
699 # Preprocess, compile, assemble.
700 if ($line =~ /\s(-E|-S|-c)\b/) {
702 $flag_preprocess = 1 if $1 eq '-E';
703 $compile = 1 if $1 eq '-S' or $1 eq '-c';
704 # Otherwise assume we are linking.
709 # Get all file extensions on this line.
710 my @extensions = $line =~ /$file_extension_regex/go;
711 # Ignore all unknown extensions to speedup the search below.
712 @extensions = grep { exists $extension{$_} } @extensions;
714 # These file types don't require preprocessing.
715 if (extension_found(\%extensions_no_preprocess, @extensions)) {
718 # These file types require preprocessing.
719 if (extension_found(\%extensions_preprocess, @extensions)) {
723 # If there are source files then it's compiling/linking in one step
724 # and we must check both. We only check for source files here, because
725 # header files cause too many false positives.
726 if (not $flag_preprocess
727 and extension_found(\%extensions_compile_link, @extensions)) {
728 # Assembly files don't need CFLAGS.
729 if (not extension_found(\%extensions_compile, @extensions)
730 and extension_found(\%extensions_no_compile, @extensions)) {
738 # Assume CXXFLAGS are required when a C++ file is specified in the
742 and extension_found(\%extensions_compile_cpp, @extensions)) {
747 if ($option_buildd) {
748 $statistics{preprocess}++ if $preprocess;
749 $statistics{compile}++ if $compile;
750 $statistics{compile_cpp}++ if $compile_cpp;
751 $statistics{link}++ if $link;
754 # Check hardening flags.
756 if ($compile and not all_flags_used($line, \@missing, @cflags)
757 # Libraries linked with -fPIC don't have to (and can't) be
758 # linked with -fPIE as well. It's no error if only PIE flags
760 and not pic_pie_conflict($line, $harden_pie, \@missing, @def_cflags_pie)
761 # Assume dpkg-buildflags returns the correct flags.
762 and not $line =~ /`dpkg-buildflags --get CFLAGS`/) {
763 if (not $option_buildd) {
764 error_flags('CFLAGS missing', \@missing, \%flag_renames, $input[$i]);
766 $statistics{compile_missing}++;
769 } elsif ($compile_cpp and not all_flags_used($line, \@missing, @cflags)
770 # Libraries linked with -fPIC don't have to (and can't) be
771 # linked with -fPIE as well. It's no error if only PIE flags
773 and not pic_pie_conflict($line, $harden_pie, \@missing, @def_cflags_pie)
774 # Assume dpkg-buildflags returns the correct flags.
775 and not $line =~ /`dpkg-buildflags --get CXXFLAGS`/) {
776 if (not $option_buildd) {
777 error_flags('CXXFLAGS missing', \@missing, \%flag_renames, $input[$i]);
779 $statistics{compile_cpp_missing}++;
783 if ($preprocess and not all_flags_used($line, \@missing, @cppflags)
784 # Assume dpkg-buildflags returns the correct flags.
785 and not $line =~ /`dpkg-buildflags --get CPPFLAGS`/) {
786 if (not $option_buildd) {
787 error_flags('CPPFLAGS missing', \@missing, \%flag_renames, $input[$i]);
789 $statistics{preprocess_missing}++;
793 if ($link and not all_flags_used($line, \@missing, @ldflags)
794 # Same here, -fPIC conflicts with -fPIE.
795 and not pic_pie_conflict($line, $harden_pie, \@missing, @def_ldflags_pie)
796 # Assume dpkg-buildflags returns the correct flags.
797 and not $line =~ /`dpkg-buildflags --get LDFLAGS`/) {
798 if (not $option_buildd) {
799 error_flags('LDFLAGS missing', \@missing, \%flag_renames, $input[$i]);
801 $statistics{link_missing}++;
808 # Print statistics for buildd mode, only output in this mode.
809 if ($option_buildd) {
812 if ($statistics{preprocess_missing}) {
813 push @warning, sprintf "CPPFLAGS %d (of %d)",
814 $statistics{preprocess_missing},
815 $statistics{preprocess};
817 if ($statistics{compile_missing}) {
818 push @warning, sprintf "CFLAGS %d (of %d)",
819 $statistics{compile_missing},
820 $statistics{compile};
822 if ($statistics{compile_cpp_missing}) {
823 push @warning, sprintf "CXXFLAGS %d (of %d)",
824 $statistics{compile_cpp_missing},
825 $statistics{compile_cpp};
827 if ($statistics{link_missing}) {
828 push @warning, sprintf "LDFLAGS %d (of %d)",
829 $statistics{link_missing},
832 if (scalar @warning) {
833 local $" = ', '; # array join string
834 print "W-dpkg-buildflags-missing @warning missing\n";
837 if ($statistics{commands_nonverbose}) {
838 printf "W-compiler-flags-hidden %d (of %d) hidden\n",
839 $statistics{commands_nonverbose},
840 $statistics{commands},
852 blhc - build log hardening check, checks build logs for missing hardening flags
856 B<blhc> [I<options>] I<E<lt>dpkg-buildpackage build log fileE<gt>..>
860 blhc is a small tool which checks build logs for missing hardening flags and
861 other important warnings. It's licensed under the GPL 3 or later.
869 Force check for all +all (+pie, +bindnow) hardening flags. By default it's
872 =item B<--arch> I<architecture>
874 Set the specific architecture (e.g. amd64, armel, etc.), automatically
875 disables hardening flags not available on this architecture. Is detected
876 automatically if dpkg-buildpackage is used.
880 Force check for all +bindnow hardening flags. By default it's auto detected.
884 Special mode for buildds when automatically parsing log files. The following
885 changes are in effect:
891 Don't check hardening flags in old log files (if dpkg-dev << 1.16.1 is
898 Use colored (ANSI) output for warning messages.
902 Force check for all +pie hardening flags. By default it's auto detected.
904 =item B<-h -? --help>
906 Print available options.
910 Print version number and license.
914 Auto detection for B<--pie> and B<--bindnow> only works if at least one
915 command uses the required hardening flag (e.g. -fPIE). Then it's required for
916 all other commands as well.
920 The exit status is a "bit mask", each listed status is ORed when the error
921 condition occurs to get the result.
931 No compiler commands were found.
935 Invalid arguments/options given to blhc.
943 Missing hardening flags.
947 Hardening wrapper detected, no tests performed.
953 Simon Ruderich, E<lt>simon@ruderich.orgE<gt>
955 =head1 COPYRIGHT AND LICENSE
957 Copyright (C) 2012 by Simon Ruderich
959 This program is free software: you can redistribute it and/or modify
960 it under the terms of the GNU General Public License as published by
961 the Free Software Foundation, either version 3 of the License, or
962 (at your option) any later version.
964 This program is distributed in the hope that it will be useful,
965 but WITHOUT ANY WARRANTY; without even the implied warranty of
966 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
967 GNU General Public License for more details.
969 You should have received a copy of the GNU General Public License
970 along with this program. If not, see <http://www.gnu.org/licenses/>.