diff options
Diffstat (limited to 'dh_strip')
| -rwxr-xr-x | dh_strip | 445 |
1 files changed, 445 insertions, 0 deletions
diff --git a/dh_strip b/dh_strip new file mode 100755 index 0000000..5cd32c1 --- /dev/null +++ b/dh_strip @@ -0,0 +1,445 @@ +#!/usr/bin/perl + +=head1 NAME + +dh_strip - strip executables, shared libraries, and some static libraries + +=cut + +use strict; +use warnings; +use File::Find; +use Debian::Debhelper::Dh_Lib; + +our $VERSION = DH_BUILTIN_VERSION; + +=head1 SYNOPSIS + +B<dh_strip> [S<I<debhelper options>>] [B<-X>I<item>] [B<--dbg-package=>I<package>] [B<--keep-debug>] + +=head1 DESCRIPTION + +B<dh_strip> is a debhelper program that is responsible for stripping +out debug symbols in executables, shared libraries, and static +libraries that are not needed during execution. + +This program examines your package build directories and works out what +to strip on its own. It uses L<file(1)> and file permissions and filenames +to figure out what files are shared libraries (F<*.so>), executable binaries, +and static (F<lib*.a>) and debugging libraries (F<lib*_g.a>, F<debug/*.so>), and +strips each as much as is possible. (Which is not at all for debugging +libraries.) In general it seems to make very good guesses, and will do the +right thing in almost all cases. + +Since it is very hard to automatically guess if a file is a +module, and hard to determine how to strip a module, B<dh_strip> does not +currently deal with stripping binary modules such as F<.o> files. + +=head1 OPTIONS + +=over 4 + +=item B<-X>I<item>, B<--exclude=>I<item> + +Exclude files that contain I<item> anywhere in their filename from being +stripped. You may use this option multiple times to build up a list of +things to exclude. + +=item B<--dbg-package=>I<package> + +B<This option is a now special purpose option that you normally do not +need>. In most cases, there should be little reason to use this +option for new source packages as debhelper automatically generates +debug packages ("dbgsym packages"). B<If you have a manual +--dbg-package> that you want to replace with an automatically +generated debug symbol package, please see the B<--dbgsym-migration> +option. + +Causes B<dh_strip> to save debug symbols stripped from the packages it acts on +as independent files in the package build directory of the specified debugging +package. + +For example, if your packages are libfoo and foo and you want to include a +I<foo-dbg> package with debugging symbols, use B<dh_strip --dbg-package=>I<foo-dbg>. + +This option implies B<--no-automatic-dbgsym> and I<cannot> be used +with B<--automatic-dbgsym> or B<--dbgsym-migration>. + +=item B<-k>, B<--keep-debug> + +B<This option is a now special purpose option that you normally do not +need>. In most cases, there should be little reason to use this +option for new source packages as debhelper automatically generates +debug packages ("dbgsym packages"). B<If you have a manual +--dbg-package> that you want to replace with an automatically +generated debug symbol package, please see the B<--dbgsym-migration> +option. + +Debug symbols will be retained, but split into an independent +file in F<usr/lib/debug/> in the package build directory. B<--dbg-package> +is easier to use than this option, but this option is more flexible. + +This option implies B<--no-automatic-dbgsym> and I<cannot> be used +with B<--automatic-dbgsym>. + +=item B<--dbgsym-migration=>I<package-relation> + +This option is used to migrate from a manual "-dbg" package (created +with B<--dbg-package>) to an automatic generated debug symbol +package. This option should describe a valid B<Replaces>- and +B<Breaks>-relation, which will be added to the debug symbol package to +avoid file conflicts with the (now obsolete) -dbg package. + +This option implies B<--automatic-dbgsym> and I<cannot> be used with +B<--keep-debug>, B<--dbg-package> or B<--no-automatic-dbgsym>. + +Examples: + + dh_strip --dbgsym-migration='libfoo-dbg (<< 2.1-3~)' + + dh_strip --dbgsym-migration='libfoo-tools-dbg (<< 2.1-3~), libfoo2-dbg (<< 2.1-3~)' + +=item B<--automatic-dbgsym>, B<--no-automatic-dbgsym> + +Control whether B<dh_strip> should be creating debug symbol packages +when possible. + +The default is to create debug symbol packages. + +=item B<--ddebs>, B<--no-ddebs> + +Historical name for B<--automatic-dbgsym> and B<--no-automatic-dbgsym>. + +=item B<--ddeb-migration=>I<package-relation> + +Historical name for B<--dbgsym-migration>. + +=back + +=head1 NOTES + +If the B<DEB_BUILD_OPTIONS> environment variable contains B<nostrip>, +nothing will be stripped, in accordance with Debian policy (section +10.1 "Binaries"). This will also inhibit the automatic creation of +debug symbol packages. + +The automatic creation of debug symbol packages can also be prevented +by adding B<noautodbgsym> to the B<DEB_BUILD_OPTIONS> environment +variable. However, B<dh_strip> will still add debuglinks to ELF +binaries when this flag is set. This is to ensure that the regular +deb package will be identical with and without this flag (assuming it +is otherwise "bit-for-bit" reproducible). + +=head1 CONFORMS TO + +Debian policy, version 3.0.1 + +=cut + +init(options => { + 'keep-debug|keep|k' => \$dh{K_FLAG}, + 'dbgsym-migration=s' => \$dh{MIGRATE_DBGSYM}, + 'automatic-dbgsym!' => \$dh{ENABLE_DBGSYM}, + # Deprecated variants + 'ddeb-migration=s' => \$dh{MIGRATE_DBGSYM}, + 'ddebs!' => \$dh{ENABLE_DBGSYM}, + +}); + +if ($dh{MIGRATE_DBGSYM}) { + error("--keep-debug and --dbgsym-migration are mutually exclusive") if ($dh{K_FLAG}); + error("--dbg-package and --dbgsym-migration are mutually exclusive") if ($dh{DEBUGPACKAGE}); +} + +if ($dh{ENABLE_DBGSYM}) { + error("--keep-debug and explicit --automatic-dbgsym are mutually exclusive") if ($dh{K_FLAG}); + error("--dbg-package and explicit --automatic-dbgsym are mutually exclusive") if ($dh{DEBUGPACKAGE}); +} + +$dh{ENABLE_DBGSYM} = 1 if not defined($dh{ENABLE_DBGSYM}); + +if ($dh{MIGRATE_DBGSYM} and not $dh{ENABLE_DBGSYM}) { + error("--dbgsym-migration and --no-automatic-dbgsym are mutually exclusive"); +} + +# This variable can be used to turn off stripping (see Policy). +exit 0 if (get_buildoption('nostrip')); + +my $no_auto_dbgsym = 0; +$no_auto_dbgsym = 1 if get_buildoption('noautodbgsym') or get_buildoption('noddebs'); + +# Check if a file is an elf binary, shared library, or static library, +# for use by File::Find. It'll fill the 3 first arrays with anything +# it finds. The @build_ids will be the collected build-ids (if any) +my (@shared_libs, @executables, @static_libs, @build_ids, %file_output); +sub testfile { + my $fn = $_; + return if -l $fn; # Always skip symlinks. + + # See if we were asked to exclude this file. + # Note that we have to test on the full filename, including directory. + if (excludefile($fn)) { + $File::Find::prune = 1 if -d _; + return; + } + # Ignore the .../debug/.build-id/ directory. It is not really helpful + # to strip debug symbols. + $File::Find::prune = 1 if -d _ && index($fn, '/debug/.build-id/') > -1; + return if -d _; + + # Is it a debug library in a debug subdir? + return if $fn=~m{debug/.*\.so}; + return if $fn=~m{/guile/.*\.go$}; + + # Exploit the previous stat call to get the $mode, so we can check + # later if it is executable or not. + # + # NB: compat() can issue a stat, so we /should/ do this now + my (undef, undef, $mode, undef) = stat(_); + + if (compat(10)) { + # In compat 10 and earlier, we used filenames and file(1) + + # Does its filename look like a shared library? + # - *.cmxs are OCaml native code shared libraries + # - *.node are also native ELF binaries (for node-js) + if ($fn =~ m/\.(?:so.*?|cmxs|node)$/) { + # Ok, do the expensive test. + my $type = get_file_type($fn, 1); + if ($type =~ m/ELF.*shared/) { + push @shared_libs, $fn; + return; + } + } + + # -x is not good enough for this test + if ($mode & 0111) { + # Ok, expensive test. + my $type = get_file_type($fn, 1); + if ($type =~ m/ELF.*(executable|shared)/) { + push(@executables, $fn); + return; + } + } + } else { + # In compat 11, we check the ELF header manually (because bulking file(1) is a pain and + # it is too slow otherwise) + + if (is_so_or_exec_elf_file($fn)) { + # -x is not good enough for this test + if ($mode & 0111) { + push(@executables, $fn); + } else { + push(@shared_libs, $fn); + } + return; + } + } + # Is it a static library, and not a debug library? + if ($fn =~ m/\/lib[^\/]*\.a$/ && $fn !~ m/.*_g\.a$/) { + # Is it a binary file, or something else (maybe a linker + # script on Hurd, for example? I don't use file, because + # file returns a variety of things on static libraries. + if (-B $fn) { + push @static_libs, $fn; + return; + } + } +} + +sub write_buildid_file { + my ($package, $build_ids) = @_; + my $dir = "debian/.debhelper/${package}"; + my $path = "${dir}/dbgsym-build-ids"; + install_dir($dir); + open(my $fd, '>>', $path) or error("open $path failed: $!"); + print {$fd} join(q{ }, sort(@{$build_ids})) . ' '; + close($fd) or error("close $path failed: $!"); +} + +# I could just use `file $_[0]`, but this is safer +sub get_file_type { + my ($file, $cache_ok) = @_; + return $file_output{$file} if $cache_ok && $file_output{$file}; + my @file_args = Debian::Debhelper::Dh_Lib::_internal_optional_file_args(); + my @cmdline = ('file', @file_args, '--brief', '-e', 'apptype', '-e', 'ascii', '-e', 'encoding', '-e', 'cdf', + '-e', 'compress', '-e', 'tar', '--', $file); + + open(my $fd, '-|', @cmdline) // error("cannot fork+exec file: $!"); + my $type = <$fd>; + close($fd) || error_exitcode(escape_shell(@cmdline)); + + error("file(1) gave no result for $file!?") if (not $type) ; + return $file_output{$file} = $type; +} + +sub make_debug { + my ($objcopy, $file, $tmp, $desttmp, $use_build_id) = @_; + my ($debug_path, $debug_build_id); + + # Don't try to copy debug symbols out if the file is already + # stripped. + # + # Disable caching for non-build-id based extractions. + # Unfortunately, it breaks when there are hardlinks to the same + # ELF files. + my $file_info = get_file_type($file, $use_build_id ? 1 : 0); + return unless $file_info =~ /not stripped/; + + if ($use_build_id) { + if ($file_info =~ m/BuildID\[sha1]\s*=\s*([0-9a-f]{2})([0-9a-f]+)/ or + `LC_ALL=C readelf -n $file`=~ /^\s+Build ID: ([0-9a-f]{2})([0-9a-f]+)$/m) { + $debug_path=$desttmp."/usr/lib/debug/.build-id/$1/$2.debug"; + $debug_build_id="${1}${2}"; + push(@build_ids, $debug_build_id); + } else { + # For dbgsyms, we need build-id (else it will not be + # co-installable). + warning("Could not find the BuildID in $file"); + return if $use_build_id > 1; + } + } + if (not $debug_path) { + # Either not using build_id OR no build-id available + my ($base_file)=$file=~/^\Q$tmp\E(.*)/; + $debug_path=$desttmp."/usr/lib/debug/".$base_file; + } + install_dir(dirname($debug_path)); + if (compat(8) && $use_build_id < 2) { + doit($objcopy, "--only-keep-debug", $file, $debug_path); + } + else { + # Compat 9 OR a dbgsym package. + doit($objcopy, "--only-keep-debug", "--compress-debug-sections", $file, $debug_path) unless -e $debug_path; + } + + # No reason for this to be executable. + reset_perm_and_owner(0644, $debug_path); + return $debug_path; +} + +sub attach_debug { + my ($objcopy, $file, $debug_path) = @_; + doit($objcopy, "--add-gnu-debuglink", $debug_path, $file); +} + +my %all_packages = map { $_ => 1 } getpackages(); + +sub process_packages { + foreach my $package (@_) { + my $tmp=tmpdir($package); + my $objcopy = cross_command($package, "objcopy"); + my $strip = cross_command($package, "strip"); + + # Support for keeping the debugging symbols in a detached file. + my $keep_debug=$dh{K_FLAG}; + my $debugtmp=$tmp; + my $use_build_id = compat(8) ? 0 : 1; + if ($dh{DEBUGPACKAGE}) { + $keep_debug=1; + my $debugpackage=$dh{DEBUGPACKAGE}; + error("debug package $debugpackage is not listed in the control file") if (!$all_packages{$debugpackage}); + $debugtmp=tmpdir($debugpackage); + } + # Temporary workaround: Do not build dbgsym packages for udebs as + # dpkg-gencontrol and dpkg-deb does not agree on the file + # extension. + if ($dh{ENABLE_DBGSYM} and not $keep_debug and not package_is_arch_all($package) and not is_udeb($package)) { + # Avoid creating a dbgsym that would clash with a registered + # package or looks like a manual -dbg package. + if (not $all_packages{"${package}-dbgsym"} and $package !~ m/-dbg(?:sym)?$/) { + $debugtmp = dbgsym_tmpdir($package); + $keep_debug = 1; + $use_build_id = 2; + } + } + %file_output=@shared_libs=@executables=@static_libs=(); + find({ + wanted => \&testfile, + no_chdir => 1, + }, $tmp); + + foreach (@shared_libs) { + my $debug_path = make_debug($objcopy, $_, $tmp, $debugtmp, $use_build_id) if $keep_debug; + # Note that all calls to strip on shared libs + # *must* include the --strip-unneeded. + doit($strip, "--remove-section=.comment", "--remove-section=.note", "--strip-unneeded", $_); + attach_debug($objcopy, $_, $debug_path) if defined $debug_path; + } + + foreach (@executables) { + my $debug_path = make_debug($objcopy, $_, $tmp, $debugtmp, $use_build_id) if $keep_debug; + doit($strip, "--remove-section=.comment", "--remove-section=.note", $_); + attach_debug($objcopy, $_, $debug_path) if defined $debug_path; + } + + foreach (@static_libs) { + # NB: The short variant (-D) is broken in Jessie + # (binutils/2.25-3) + doit($strip, '--strip-debug', '--remove-section=.comment', + '--remove-section=.note', '--enable-deterministic-archives', + '-R', '.gnu.lto_*', '-R', '.gnu.debuglto_*', + '-N', '__gnu_lto_slim', '-N', '__gnu_lto_v1', + $_); + } + if (-d "$tmp/usr/lib/debug/.dwz" and ($use_build_id > 1 or ($dh{DEBUGPACKAGE} and $dh{DEBUGPACKAGE} ne $package))) { + my @files = glob_expand(["$tmp/usr/lib/debug/.dwz"], \&glob_expand_error_handler_reject, '*'); + install_dir("$debugtmp/usr/lib/debug/.dwz"); + xargs(\@files, 'cp', '--reflink=auto', "-a", XARGS_INSERT_PARAMS_HERE, "$debugtmp/usr/lib/debug/.dwz"); + doit('rm', '-fr', "$tmp/usr/lib/debug/.dwz"); + doit('rmdir', '-p', '--ignore-fail-on-non-empty', "$tmp/usr/lib/debug"); + } + + if ($no_auto_dbgsym and $use_build_id > 1) { + # When DEB_BUILD_OPTIONS contains noautodbgsym, remove the + # dbgsym dir and clear the build-ids. + # + # Note we have to extract the dbg symbols as usual, since + # attach_debug (objcopy --add-gnu-debuglink) requires the dbg + # file to exist. + doit('rm', '-fr', $debugtmp); + @build_ids = (); + } + if ($use_build_id > 1 and -d $debugtmp) { + my $dbgsym_docdir = "${debugtmp}/usr/share/doc"; + my $doc_symlink = "${dbgsym_docdir}/${package}-dbgsym"; + if ( not -l $doc_symlink and not -e _ ) { + install_dir($dbgsym_docdir); + make_symlink_raw_target($package, $doc_symlink); + } + if ($dh{MIGRATE_DBGSYM}) { + my $path = "debian/.debhelper/${package}/dbgsym-migration"; + open(my $fd, '>', $path) or error("open $path failed: $!"); + print {$fd} "$dh{MIGRATE_DBGSYM}\n"; + close($fd) or error("close $path failed: $!"); + } + } + if ($use_build_id > 1 and @build_ids) { + write_buildid_file($package, \@build_ids); + @build_ids = (); + } + } + if (@build_ids and $dh{DEBUGPACKAGE}) { + write_buildid_file($dh{DEBUGPACKAGE}, \@build_ids); + } +} + +if ($dh{DEBUGPACKAGE}) { + # Non-deterministic issues with --dbg-package and parallelism (see + # #872007). Analysis and patches welcome for this case. + process_packages(@{$dh{DOPACKAGES}}); +} else { + on_pkgs_in_parallel(\&process_packages); +} + +=head1 SEE ALSO + +L<debhelper(7)> + +This program is a part of debhelper. + +=head1 AUTHOR + +Joey Hess <joeyh@debian.org> + +=cut |