1 ### the gnu tar specification:
2 ### http://www.gnu.org/software/tar/manual/tar.html
4 ### and the pax format spec, which tar derives from:
5 ### http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
13 use Carp qw(carp croak);
15 use File::Spec::Unix ();
18 use Archive::Tar::File;
19 use Archive::Tar::Constant;
24 use vars qw[$DEBUG $error $VERSION $WARN $FOLLOW_SYMLINK $CHOWN $CHMOD
25 $DO_NOT_USE_PREFIX $HAS_PERLIO $HAS_IO_STRING
26 $INSECURE_EXTRACT_MODE @ISA @EXPORT
30 @EXPORT = ( COMPRESS_GZIP, COMPRESS_BZIP );
37 $DO_NOT_USE_PREFIX = 0;
38 $INSECURE_EXTRACT_MODE = 0;
42 $HAS_PERLIO = $Config::Config{useperlio};
44 ### try and load IO::String anyway, so you can dynamically
45 ### switch between perlio and IO::String
46 $HAS_IO_STRING = eval {
55 Archive::Tar - module for manipulations of tar archives
60 my $tar = Archive::Tar->new;
62 $tar->read('origin.tgz');
65 $tar->add_files('file/foo.pl', 'docs/README');
66 $tar->add_data('file/baz.txt', 'This is the contents now');
68 $tar->rename('oldname', 'new/file/name');
70 $tar->write('files.tar'); # plain tar
71 $tar->write('files.tgz', COMPRESSED_GZIP); # gzip compressed
72 $tar->write('files.tbz', COMPRESSED_BZIP); # bzip2 compressed
76 Archive::Tar provides an object oriented mechanism for handling tar
77 files. It provides class methods for quick and easy files handling
78 while also allowing for the creation of tar file objects for custom
79 manipulation. If you have the IO::Zlib module installed,
80 Archive::Tar will also support compressed or gzipped tar files.
82 An object of class Archive::Tar represents a .tar(.gz) archive full
87 =head2 Archive::Tar->new( [$file, $compressed] )
89 Returns a new Tar object. If given any arguments, C<new()> calls the
90 C<read()> method automatically, passing on the arguments provided to
93 If C<new()> is invoked with arguments and the C<read()> method fails
94 for any reason, C<new()> returns undef.
103 ### install get/set accessors for this object.
104 for my $key ( keys %$tmpl ) {
106 *{__PACKAGE__."::$key"} = sub {
108 $self->{$key} = $_[0] if @_;
109 return $self->{$key};
115 $class = ref $class if ref $class;
117 ### copying $tmpl here since a shallow copy makes it use the
118 ### same aref, causing for files to remain in memory always.
119 my $obj = bless { _data => [ ], _file => 'Unknown' }, $class;
122 unless ( $obj->read( @_ ) ) {
123 $obj->_error(qq[No data could be read from file]);
131 =head2 $tar->read ( $filename|$handle, [$compressed, {opt => 'val'}] )
133 Read the given tar file into memory.
134 The first argument can either be the name of a file or a reference to
135 an already open filehandle (or an IO::Zlib object if it's compressed)
137 The C<read> will I<replace> any previous content in C<$tar>!
139 The second argument may be considered optional, but remains for
140 backwards compatibility. Archive::Tar now looks at the file
141 magic to determine what class should be used to open the file
142 and will transparently Do The Right Thing.
144 Archive::Tar will warn if you try to pass a bzip2 compressed file and the
145 IO::Zlib / IO::Uncompress::Bunzip2 modules are not available and simply return.
147 Note that you can currently B<not> pass a C<gzip> compressed
148 filehandle, which is not opened with C<IO::Zlib>, a C<bzip2> compressed
149 filehandle, which is not opened with C<IO::Uncompress::Bunzip2>, nor a string
150 containing the full archive information (either compressed or
151 uncompressed). These are worth while features, but not currently
152 implemented. See the C<TODO> section.
154 The third argument can be a hash reference with options. Note that
155 all options are case-sensitive.
161 Do not read more than C<limit> files. This is useful if you have
162 very big archives, and are only interested in the first few files.
166 Can be set to a regular expression. Only files with names that match
167 the expression will be read.
171 If set to true, immediately extract entries when reading them. This
172 gives you the same memory break as the C<extract_archive> function.
173 Note however that entries will not be read into memory, but written
174 straight to disk. This means no C<Archive::Tar::File> objects are
175 created for you to inspect.
179 All files are stored internally as C<Archive::Tar::File> objects.
180 Please consult the L<Archive::Tar::File> documentation for details.
182 Returns the number of files read in scalar context, and a list of
183 C<Archive::Tar::File> objects in list context.
190 my $gzip = shift || 0;
191 my $opts = shift || {};
193 unless( defined $file ) {
194 $self->_error( qq[No file to read from!] );
197 $self->_file( $file );
200 my $handle = $self->_get_handle($file, $gzip, READ_ONLY->( ZLIB ) )
203 my $data = $self->_read_tar( $handle, $opts ) or return;
205 $self->_data( $data );
207 return wantarray ? @$data : scalar @$data;
212 my $file = shift; return unless defined $file;
213 return $file if ref $file;
214 my $compress = shift || 0;
215 my $mode = shift || READ_ONLY->( ZLIB ); # default to read only
218 ### get a FH opened to the right class, so we can use it transparently
219 ### throughout the program
221 { ### reading magic only makes sense if we're opening a file for
222 ### reading. otherwise, just use what the user requested.
224 if( MODE_READ->($mode) ) {
225 open my $tmp, $file or do {
226 $self->_error( qq[Could not open '$file' for reading: $!] );
230 ### read the first 4 bites of the file to figure out which class to
231 ### use to open the file.
232 sysread( $tmp, $magic, 4 );
237 ### if you asked specifically for bzip compression, or if we're in
238 ### read mode and the magic numbers add up, use bzip
240 ($compress eq COMPRESS_BZIP) or
241 ( MODE_READ->($mode) and $magic =~ BZIP_MAGIC_NUM )
245 ### different reader/writer modules, different error vars... sigh
246 if( MODE_READ->($mode) ) {
247 $fh = IO::Uncompress::Bunzip2->new( $file ) or do {
248 $self->_error( qq[Could not read '$file': ] .
249 $IO::Uncompress::Bunzip2::Bunzip2Error
255 $fh = IO::Compress::Bzip2->new( $file ) or do {
256 $self->_error( qq[Could not write to '$file': ] .
257 $IO::Compress::Bzip2::Bzip2Error
264 ### if you asked for compression, if you wanted to read or the gzip
265 ### magic number is present (redundant with read)
267 $compress or MODE_READ->($mode) or $magic =~ GZIP_MAGIC_NUM
272 unless( $fh->open( $file, $mode ) ) {
273 $self->_error(qq[Could not create filehandle for '$file': $!]);
281 unless( $fh->open( $file, $mode ) ) {
282 $self->_error(qq[Could not create filehandle for '$file': $!]);
286 ### enable bin mode on tar archives
297 my $handle = shift or return;
298 my $opts = shift || {};
300 my $count = $opts->{limit} || 0;
301 my $filter = $opts->{filter};
302 my $extract = $opts->{extract} || 0;
304 ### set a cap on the amount of files to extract ###
306 $limit = 1 if $count > 0;
311 my $real_name; # to set the name of a file when
312 # we're encountering @longlink
316 while( $handle->read( $chunk, HEAD ) ) {
317 ### IO::Zlib doesn't support this yet
318 my $offset = eval { tell $handle } || 'unknown';
321 my $gzip = GZIP_MAGIC_NUM;
322 if( $chunk =~ /$gzip/ ) {
323 $self->_error( qq[Cannot read compressed format in tar-mode] );
328 ### if we can't read in all bytes... ###
329 last if length $chunk != HEAD;
331 ### Apparently this should really be two blocks of 512 zeroes,
332 ### but GNU tar sometimes gets it wrong. See comment in the
333 ### source code (tar.c) to GNU cpio.
334 next if $chunk eq TAR_END;
336 ### according to the posix spec, the last 12 bytes of the header are
337 ### null bytes, to pad it to a 512 byte block. That means if these
338 ### bytes are NOT null bytes, it's a corrrupt header. See:
339 ### www.koders.com/c/fidCE473AD3D9F835D690259D60AD5654591D91D5BA.aspx
341 { my $nulls = join '', "\0" x 12;
342 unless( $nulls eq substr( $chunk, 500, 12 ) ) {
343 $self->_error( qq[Invalid header block at offset $offset] );
348 ### pass the realname, so we can set it 'proper' right away
349 ### some of the heuristics are done on the name, so important
352 { my %extra_args = ();
353 $extra_args{'name'} = $$real_name if defined $real_name;
355 unless( $entry = Archive::Tar::File->new( chunk => $chunk,
358 $self->_error( qq[Couldn't read chunk at offset $offset] );
364 ### http://www.gnu.org/manual/tar/html_node/tar_139.html
365 next if $entry->is_label;
367 if( length $entry->type and ($entry->is_file || $entry->is_longlink) ) {
369 if ( $entry->is_file && !$entry->validate ) {
370 ### sometimes the chunk is rather fux0r3d and a whole 512
371 ### bytes ends up in the ->name area.
372 ### clean it up, if need be
373 my $name = $entry->name;
374 $name = substr($name, 0, 100) if length $name > 100;
377 $self->_error( $name . qq[: checksum error] );
381 my $block = BLOCK_SIZE->( $entry->size );
383 $data = $entry->get_content_by_ref;
385 ### just read everything into memory
386 ### can't do lazy loading since IO::Zlib doesn't support 'seek'
387 ### this is because Compress::Zlib doesn't support it =/
388 ### this reads in the whole data in one read() call.
389 if( $handle->read( $$data, $block ) < $block ) {
390 $self->_error( qq[Read error on tarfile (missing data) '].
391 $entry->full_path ."' at offset $offset" );
395 ### throw away trailing garbage ###
396 substr ($$data, $entry->size) = "" if defined $$data;
398 ### part II of the @LongLink munging -- need to do /after/
399 ### the checksum check.
400 if( $entry->is_longlink ) {
401 ### weird thing in tarfiles -- if the file is actually a
402 ### @LongLink, the data part seems to have a trailing ^@
403 ### (unprintable) char. to display, pipe output through less.
404 ### but that doesn't *always* happen.. so check if the last
405 ### character is a control character, and if so remove it
406 ### at any rate, we better remove that character here, or tests
407 ### like 'eq' and hashlook ups based on names will SO not work
408 ### remove it by calculating the proper size, and then
409 ### tossing out everything that's longer than that size.
411 ### count number of nulls
412 my $nulls = $$data =~ tr/\0/\0/;
414 ### cut data + size by that many bytes
415 $entry->size( $entry->size - $nulls );
416 substr ($$data, $entry->size) = "";
420 ### clean up of the entries.. posix tar /apparently/ has some
421 ### weird 'feature' that allows for filenames > 255 characters
422 ### they'll put a header in with as name '././@LongLink' and the
423 ### contents will be the name of the /next/ file in the archive
424 ### pretty crappy and kludgy if you ask me
426 ### set the name for the next entry if this is a @LongLink;
427 ### this is one ugly hack =/ but needed for direct extraction
428 if( $entry->is_longlink ) {
431 } elsif ( defined $real_name ) {
432 $entry->name( $$real_name );
437 ### skip this entry if we're filtering
438 if ($filter && $entry->name !~ $filter) {
441 ### skip this entry if it's a pax header. This is a special file added
442 ### by, among others, git-generated tarballs. It holds comments and is
443 ### not meant for extracting. See #38932: pax_global_header extracted
444 } elsif ( $entry->name eq PAX_HEADER ) {
448 $self->_extract_file( $entry ) if $extract
449 && !$entry->is_longlink
450 && !$entry->is_unknown
451 && !$entry->is_label;
453 ### Guard against tarfiles with garbage at the end
454 last LOOP if $entry->name eq '';
456 ### push only the name on the rv if we're extracting
457 ### -- for extract_archive
458 push @$tarfile, ($extract ? $entry->name : $entry);
461 $count-- unless $entry->is_longlink || $entry->is_dir;
462 last LOOP unless $count;
471 =head2 $tar->contains_file( $filename )
473 Check if the archive contains a certain file.
474 It will return true if the file is in the archive, false otherwise.
476 Note however, that this function does an exact match using C<eq>
477 on the full path. So it cannot compensate for case-insensitive file-
478 systems or compare 2 paths to see if they would point to the same
487 return unless defined $full;
489 ### don't warn if the entry isn't there.. that's what this function
490 ### is for after all.
492 return 1 if $self->_find_entry($full);
496 =head2 $tar->extract( [@filenames] )
498 Write files whose names are equivalent to any of the names in
499 C<@filenames> to disk, creating subdirectories as necessary. This
500 might not work too well under VMS.
501 Under MacPerl, the file's modification time will be converted to the
502 MacOS zero of time, and appropriate conversions will be done to the
503 path. However, the length of each element of the path is not
504 inspected to see whether it's longer than MacOS currently allows (32
507 If C<extract> is called without a list of file names, the entire
508 contents of the archive are extracted.
510 Returns a list of filenames extracted.
519 # use the speed optimization for all extracted files
520 local($self->{cwd}) = cwd() unless $self->{cwd};
522 ### you requested the extraction of only certian files
524 for my $file ( @args ) {
526 ### it's already an object?
527 if( UNIVERSAL::isa( $file, 'Archive::Tar::File' ) ) {
535 for my $entry ( @{$self->_data} ) {
536 next unless $file eq $entry->full_path;
538 ### we found the file you're looking for
544 return $self->_error(
545 qq[Could not find '$file' in archive] );
550 ### just grab all the file items
552 @files = $self->get_files;
555 ### nothing found? that's an error
556 unless( scalar @files ) {
557 $self->_error( qq[No files found for ] . $self->_file );
562 for my $entry ( @files ) {
563 unless( $self->_extract_file( $entry ) ) {
564 $self->_error(q[Could not extract ']. $entry->full_path .q['] );
572 =head2 $tar->extract_file( $file, [$extract_path] )
574 Write an entry, whose name is equivalent to the file name provided to
575 disk. Optionally takes a second parameter, which is the full native
576 path (including filename) the entry will be written to.
580 $tar->extract_file( 'name/in/archive', 'name/i/want/to/give/it' );
582 $tar->extract_file( $at_file_object, 'name/i/want/to/give/it' );
584 Returns true on success, false on failure.
590 my $file = shift; return unless defined $file;
593 my $entry = $self->_find_entry( $file )
594 or $self->_error( qq[Could not find an entry for '$file'] ), return;
596 return $self->_extract_file( $entry, $alt );
601 my $entry = shift or return;
604 ### you wanted an alternate extraction location ###
605 my $name = defined $alt ? $alt : $entry->full_path;
607 ### splitpath takes a bool at the end to indicate
608 ### that it's splitting a dir
609 my ($vol,$dirs,$file);
610 if ( defined $alt ) { # It's a local-OS path
611 ($vol,$dirs,$file) = File::Spec->splitpath( $alt,
614 ($vol,$dirs,$file) = File::Spec::Unix->splitpath( $name,
619 ### is $name an absolute path? ###
620 if( $vol || File::Spec->file_name_is_absolute( $dirs ) ) {
622 ### absolute names are not allowed to be in tarballs under
623 ### strict mode, so only allow it if a user tells us to do it
624 if( not defined $alt and not $INSECURE_EXTRACT_MODE ) {
626 q[Entry ']. $entry->full_path .q[' is an absolute path. ].
627 q[Not extracting absolute paths under SECURE EXTRACT MODE]
632 ### user asked us to, it's fine.
633 $dir = File::Spec->catpath( $vol, $dirs, "" );
635 ### it's a relative path ###
637 my $cwd = (ref $self and defined $self->{cwd})
641 my @dirs = defined $alt
642 ? File::Spec->splitdir( $dirs ) # It's a local-OS path
643 : File::Spec::Unix->splitdir( $dirs ); # it's UNIX-style, likely
644 # straight from the tarball
646 if( not defined $alt and
647 not $INSECURE_EXTRACT_MODE
650 ### paths that leave the current directory are not allowed under
651 ### strict mode, so only allow it if a user tells us to do this.
652 if( grep { $_ eq '..' } @dirs ) {
655 q[Entry ']. $entry->full_path .q[' is attempting to leave ].
656 q[the current working directory. Not extracting under ].
657 q[SECURE EXTRACT MODE]
662 ### the archive may be asking us to extract into a symlink. This
663 ### is not sane and a possible security issue, as outlined here:
664 ### https://rt.cpan.org/Ticket/Display.html?id=30380
665 ### https://bugzilla.redhat.com/show_bug.cgi?id=295021
666 ### https://issues.rpath.com/browse/RPL-1716
667 my $full_path = $cwd;
668 for my $d ( @dirs ) {
669 $full_path = File::Spec->catdir( $full_path, $d );
671 ### we've already checked this one, and it's safe. Move on.
672 next if ref $self and $self->{_link_cache}->{$full_path};
674 if( -l $full_path ) {
675 my $to = readlink $full_path;
676 my $diag = "symlinked directory ($full_path => $to)";
679 q[Entry ']. $entry->full_path .q[' is attempting to ].
680 qq[extract to a $diag. This is considered a security ].
681 q[vulnerability and not allowed under SECURE EXTRACT ].
687 ### XXX keep a cache if possible, so the stats become cheaper:
688 $self->{_link_cache}->{$full_path} = 1 if ref $self;
693 ### '.' is the directory delimiter, of which the first one has to
694 ### be escaped/changed.
695 map tr/\./_/, @dirs if ON_VMS;
697 my ($cwd_vol,$cwd_dir,$cwd_file)
698 = File::Spec->splitpath( $cwd );
699 my @cwd = File::Spec->splitdir( $cwd_dir );
700 push @cwd, $cwd_file if length $cwd_file;
702 ### We need to pass '' as the last elemant to catpath. Craig Berry
703 ### explains why (msgid <p0624083dc311ae541393@[172.16.52.1]>):
704 ### The root problem is that splitpath on UNIX always returns the
705 ### final path element as a file even if it is a directory, and of
706 ### course there is no way it can know the difference without checking
707 ### against the filesystem, which it is documented as not doing. When
708 ### you turn around and call catpath, on VMS you have to know which bits
709 ### are directory bits and which bits are file bits. In this case we
710 ### know the result should be a directory. I had thought you could omit
711 ### the file argument to catpath in such a case, but apparently on UNIX
713 $dir = File::Spec->catpath(
714 $cwd_vol, File::Spec->catdir( @cwd, @dirs ), ''
717 ### catdir() returns undef if the path is longer than 255 chars on VMS
718 unless ( defined $dir ) {
719 $^W && $self->_error( qq[Could not compose a path for '$dirs'\n] );
725 if( -e $dir && !-d _ ) {
726 $^W && $self->_error( qq['$dir' exists, but it's not a directory!\n] );
731 eval { File::Path::mkpath( $dir, 0, 0777 ) };
733 my $fp = $entry->full_path;
734 $self->_error(qq[Could not create directory '$dir' for '$fp': $@]);
738 ### XXX chown here? that might not be the same as in the archive
739 ### as we're only chown'ing to the owner of the file we're extracting
740 ### not to the owner of the directory itself, which may or may not
741 ### be another entry in the archive
742 ### Answer: no, gnu tar doesn't do it either, it'd be the wrong
744 #if( $CHOWN && CAN_CHOWN ) {
745 # chown $entry->uid, $entry->gid, $dir or
746 # $self->_error( qq[Could not set uid/gid on '$dir'] );
750 ### we're done if we just needed to create a dir ###
751 return 1 if $entry->is_dir;
753 my $full = File::Spec->catfile( $dir, $file );
755 if( $entry->is_unknown ) {
756 $self->_error( qq[Unknown file type for file '$full'] );
760 if( length $entry->type && $entry->is_file ) {
761 my $fh = IO::File->new;
762 $fh->open( '>' . $full ) or (
763 $self->_error( qq[Could not open file '$full': $!] ),
769 syswrite $fh, $entry->data or (
770 $self->_error( qq[Could not write data to '$full'] ),
776 $self->_error( qq[Could not close file '$full'] ),
781 $self->_make_special_file( $entry, $full ) or return;
784 ### only update the timestamp if it's not a symlink; that will change the
785 ### timestamp of the original. This addresses bug #33669: Could not update
786 ### timestamp warning on symlinks
788 utime time, $entry->mtime - TIME_OFFSET, $full or
789 $self->_error( qq[Could not update timestamp] );
792 if( $CHOWN && CAN_CHOWN ) {
793 chown $entry->uid, $entry->gid, $full or
794 $self->_error( qq[Could not set uid/gid on '$full'] );
797 ### only chmod if we're allowed to, but never chmod symlinks, since they'll
798 ### change the perms on the file they're linking too...
799 if( $CHMOD and not -l $full ) {
800 chmod $entry->mode, $full or
801 $self->_error( qq[Could not chown '$full' to ] . $entry->mode );
807 sub _make_special_file {
809 my $entry = shift or return;
810 my $file = shift; return unless defined $file;
814 if( $entry->is_symlink ) {
817 symlink( $entry->linkname, $file ) or $fail++;
820 $self->_extract_special_file_as_plain_file( $entry, $file )
824 $err = qq[Making symbolic link '$file' to '] .
825 $entry->linkname .q[' failed] if $fail;
827 } elsif ( $entry->is_hardlink ) {
830 link( $entry->linkname, $file ) or $fail++;
833 $self->_extract_special_file_as_plain_file( $entry, $file )
837 $err = qq[Making hard link from '] . $entry->linkname .
838 qq[' to '$file' failed] if $fail;
840 } elsif ( $entry->is_fifo ) {
841 ON_UNIX && !system('mknod', $file, 'p') or
842 $err = qq[Making fifo ']. $entry->name .qq[' failed];
844 } elsif ( $entry->is_blockdev or $entry->is_chardev ) {
845 my $mode = $entry->is_blockdev ? 'b' : 'c';
847 ON_UNIX && !system('mknod', $file, $mode,
848 $entry->devmajor, $entry->devminor) or
849 $err = qq[Making block device ']. $entry->name .qq[' (maj=] .
850 $entry->devmajor . qq[ min=] . $entry->devminor .
853 } elsif ( $entry->is_socket ) {
854 ### the original doesn't do anything special for sockets.... ###
858 return $err ? $self->_error( $err ) : 1;
861 ### don't know how to make symlinks, let's just extract the file as
863 sub _extract_special_file_as_plain_file {
865 my $entry = shift or return;
866 my $file = shift; return unless defined $file;
870 my $orig = $self->_find_entry( $entry->linkname );
873 $err = qq[Could not find file '] . $entry->linkname .
878 ### clone the entry, make it appear as a normal file ###
879 my $clone = $entry->clone;
880 $clone->_downgrade_to_plainfile;
881 $self->_extract_file( $clone, $file ) or last TRY;
886 return $self->_error($err);
889 =head2 $tar->list_files( [\@properties] )
891 Returns a list of the names of all the files in the archive.
893 If C<list_files()> is passed an array reference as its first argument
894 it returns a list of hash references containing the requested
895 properties of each file. The following list of properties is
896 supported: name, size, mtime (last modified date), mode, uid, gid,
897 linkname, uname, gname, devmajor, devminor, prefix.
899 Passing an array reference containing only one element, 'name', is
900 special cased to return a list of names rather than a list of hash
901 references, making it equivalent to calling C<list_files> without
908 my $aref = shift || [ ];
910 unless( $self->_data ) {
911 $self->read() or return;
914 if( @$aref == 0 or ( @$aref == 1 and $aref->[0] eq 'name' ) ) {
915 return map { $_->full_path } @{$self->_data};
919 #for my $obj ( @{$self->_data} ) {
920 # push @rv, { map { $_ => $obj->$_() } @$aref };
924 ### this does the same as the above.. just needs a +{ }
925 ### to make sure perl doesn't confuse it for a block
926 return map { my $o=$_;
927 +{ map { $_ => $o->$_() } @$aref }
936 unless( defined $file ) {
937 $self->_error( qq[No file specified] );
941 ### it's an object already
942 return $file if UNIVERSAL::isa( $file, 'Archive::Tar::File' );
944 for my $entry ( @{$self->_data} ) {
945 my $path = $entry->full_path;
946 return $entry if $path eq $file;
949 $self->_error( qq[No such file in archive: '$file'] );
953 =head2 $tar->get_files( [@filenames] )
955 Returns the C<Archive::Tar::File> objects matching the filenames
956 provided. If no filename list was passed, all C<Archive::Tar::File>
957 objects in the current Tar object are returned.
959 Please refer to the C<Archive::Tar::File> documentation on how to
960 handle these objects.
967 return @{ $self->_data } unless @_;
970 for my $file ( @_ ) {
971 push @list, grep { defined } $self->_find_entry( $file );
977 =head2 $tar->get_content( $file )
979 Return the content of the named file.
985 my $entry = $self->_find_entry( shift ) or return;
990 =head2 $tar->replace_content( $file, $content )
992 Make the string $content be the content for the file named $file.
996 sub replace_content {
998 my $entry = $self->_find_entry( shift ) or return;
1000 return $entry->replace_content( shift );
1003 =head2 $tar->rename( $file, $new_name )
1005 Rename the file of the in-memory archive to $new_name.
1007 Note that you must specify a Unix path for $new_name, since per tar
1008 standard, all files in the archive must be Unix paths.
1010 Returns true on success and false on failure.
1016 my $file = shift; return unless defined $file;
1017 my $new = shift; return unless defined $new;
1019 my $entry = $self->_find_entry( $file ) or return;
1021 return $entry->rename( $new );
1024 =head2 $tar->remove (@filenamelist)
1026 Removes any entries with names matching any of the given filenames
1027 from the in-memory archive. Returns a list of C<Archive::Tar::File>
1028 objects that remain.
1036 my %seen = map { $_->full_path => $_ } @{$self->_data};
1037 delete $seen{ $_ } for @list;
1039 $self->_data( [values %seen] );
1041 return values %seen;
1046 C<clear> clears the current in-memory archive. This effectively gives
1047 you a 'blank' object, ready to be filled again. Note that C<clear>
1048 only has effect on the object, not the underlying tarfile.
1053 my $self = shift or return;
1062 =head2 $tar->write ( [$file, $compressed, $prefix] )
1064 Write the in-memory archive to disk. The first argument can either
1065 be the name of a file or a reference to an already open filehandle (a
1068 The second argument is used to indicate compression. You can either
1069 compress using C<gzip> or C<bzip2>. If you pass a digit, it's assumed
1070 to be the C<gzip> compression level (between 1 and 9), but the use of
1071 constants is prefered:
1073 # write a gzip compressed file
1074 $tar->write( 'out.tgz', COMPRESSION_GZIP );
1076 # write a bzip compressed file
1077 $tar->write( 'out.tbz', COMPRESSION_BZIP );
1079 Note that when you pass in a filehandle, the compression argument
1080 is ignored, as all files are printed verbatim to your filehandle.
1081 If you wish to enable compression with filehandles, use an
1082 C<IO::Zlib> or C<IO::Compress::Bzip2> filehandle instead.
1084 The third argument is an optional prefix. All files will be tucked
1085 away in the directory you specify as prefix. So if you have files
1086 'a' and 'b' in your archive, and you specify 'foo' as prefix, they
1087 will be written to the archive as 'foo/a' and 'foo/b'.
1089 If no arguments are given, C<write> returns the entire formatted
1090 archive as a string, which could be useful if you'd like to stuff the
1091 archive into a socket or a pipe to gzip or something.
1098 my $file = shift; $file = '' unless defined $file;
1099 my $gzip = shift || 0;
1100 my $ext_prefix = shift; $ext_prefix = '' unless defined $ext_prefix;
1103 ### only need a handle if we have a file to print to ###
1104 my $handle = length($file)
1105 ? ( $self->_get_handle($file, $gzip, WRITE_ONLY->($gzip) )
1107 : $HAS_PERLIO ? do { open my $h, '>', \$dummy; $h }
1108 : $HAS_IO_STRING ? IO::String->new
1109 : __PACKAGE__->no_string_support();
1113 for my $entry ( @{$self->_data} ) {
1114 ### entries to be written to the tarfile ###
1117 ### only now will we change the object to reflect the current state
1118 ### of the name and prefix fields -- this needs to be limited to
1120 my $clone = $entry->clone;
1123 ### so, if you don't want use to use the prefix, we'll stuff
1124 ### everything in the name field instead
1125 if( $DO_NOT_USE_PREFIX ) {
1127 ### you might have an extended prefix, if so, set it in the clone
1128 ### XXX is ::Unix right?
1129 $clone->name( length $ext_prefix
1130 ? File::Spec::Unix->catdir( $ext_prefix,
1132 : $clone->full_path );
1133 $clone->prefix( '' );
1135 ### otherwise, we'll have to set it properly -- prefix part in the
1136 ### prefix and name part in the name field.
1139 ### split them here, not before!
1140 my ($prefix,$name) = $clone->_prefix_and_file( $clone->full_path );
1142 ### you might have an extended prefix, if so, set it in the clone
1143 ### XXX is ::Unix right?
1144 $prefix = File::Spec::Unix->catdir( $ext_prefix, $prefix )
1145 if length $ext_prefix;
1147 $clone->prefix( $prefix );
1148 $clone->name( $name );
1151 ### names are too long, and will get truncated if we don't add a
1152 ### '@LongLink' file...
1153 my $make_longlink = ( length($clone->name) > NAME_LENGTH or
1154 length($clone->prefix) > PREFIX_LENGTH
1157 ### perhaps we need to make a longlink file?
1158 if( $make_longlink ) {
1159 my $longlink = Archive::Tar::File->new(
1160 data => LONGLINK_NAME,
1162 { type => LONGLINK }
1165 unless( $longlink ) {
1166 $self->_error( qq[Could not create 'LongLink' entry for ] .
1167 qq[oversize file '] . $clone->full_path ."'" );
1171 push @write_me, $longlink;
1174 push @write_me, $clone;
1176 ### write the one, optionally 2 a::t::file objects to the handle
1177 for my $clone (@write_me) {
1179 ### if the file is a symlink, there are 2 options:
1180 ### either we leave the symlink intact, but then we don't write any
1181 ### data OR we follow the symlink, which means we actually make a
1182 ### copy. if we do the latter, we have to change the TYPE of the
1184 my $link_ok = $clone->is_symlink && $Archive::Tar::FOLLOW_SYMLINK;
1185 my $data_ok = !$clone->is_symlink && $clone->has_content;
1187 ### downgrade to a 'normal' file if it's a symlink we're going to
1188 ### treat as a regular file
1189 $clone->_downgrade_to_plainfile if $link_ok;
1191 ### get the header for this block
1192 my $header = $self->_format_tar_entry( $clone );
1194 $self->_error(q[Could not format header for: ] .
1195 $clone->full_path );
1199 unless( print $handle $header ) {
1200 $self->_error(q[Could not write header for: ] .
1205 if( $link_ok or $data_ok ) {
1206 unless( print $handle $clone->data ) {
1207 $self->_error(q[Could not write data for: ] .
1212 ### pad the end of the clone if required ###
1213 print $handle TAR_PAD->( $clone->size ) if $clone->size % BLOCK
1216 } ### done writing these entries
1219 ### write the end markers ###
1220 print $handle TAR_END x 2 or
1221 return $self->_error( qq[Could not write tar end markers] );
1223 ### did you want it written to a file, or returned as a string? ###
1224 my $rv = length($file) ? 1
1225 : $HAS_PERLIO ? $dummy
1226 : do { seek $handle, 0, 0; local $/; <$handle> };
1228 ### make sure to close the handle;
1234 sub _format_tar_entry {
1236 my $entry = shift or return;
1237 my $ext_prefix = shift; $ext_prefix = '' unless defined $ext_prefix;
1238 my $no_prefix = shift || 0;
1240 my $file = $entry->name;
1241 my $prefix = $entry->prefix; $prefix = '' unless defined $prefix;
1243 ### remove the prefix from the file name
1244 ### not sure if this is still neeeded --kane
1245 ### no it's not -- Archive::Tar::File->_new_from_file will take care of
1246 ### this for us. Even worse, this would break if we tried to add a file
1248 #if( length $prefix ) {
1249 # $file =~ s/^$match//;
1252 $prefix = File::Spec::Unix->catdir($ext_prefix, $prefix)
1253 if length $ext_prefix;
1255 ### not sure why this is... ###
1256 my $l = PREFIX_LENGTH; # is ambiguous otherwise...
1257 substr ($prefix, 0, -$l) = "" if length $prefix >= PREFIX_LENGTH;
1259 my $f1 = "%06o"; my $f2 = "%11o";
1261 ### this might be optimizable with a 'changed' flag in the file objects ###
1266 (map { sprintf( $f1, $entry->$_() ) } qw[mode uid gid]),
1267 (map { sprintf( $f2, $entry->$_() ) } qw[size mtime]),
1269 "", # checksum field - space padded a bit down
1271 (map { $entry->$_() } qw[type linkname magic]),
1273 $entry->version || TAR_VERSION,
1275 (map { $entry->$_() } qw[uname gname]),
1276 (map { sprintf( $f1, $entry->$_() ) } qw[devmajor devminor]),
1278 ($no_prefix ? '' : $prefix)
1281 ### add the checksum ###
1282 substr($tar,148,7) = sprintf("%6o\0", unpack("%16C*",$tar));
1287 =head2 $tar->add_files( @filenamelist )
1289 Takes a list of filenames and adds them to the in-memory archive.
1291 The path to the file is automatically converted to a Unix like
1292 equivalent for use in the archive, and, if on MacOS, the file's
1293 modification time is converted from the MacOS epoch to the Unix epoch.
1294 So tar archives created on MacOS with B<Archive::Tar> can be read
1295 both with I<tar> on Unix and applications like I<suntar> or
1296 I<Stuffit Expander> on MacOS.
1298 Be aware that the file's type/creator and resource fork will be lost,
1299 which is usually what you want in cross-platform archives.
1301 Returns a list of C<Archive::Tar::File> objects that were just added.
1307 my @files = @_ or return;
1310 for my $file ( @files ) {
1311 unless( -e $file || -l $file ) {
1312 $self->_error( qq[No such file: '$file'] );
1316 my $obj = Archive::Tar::File->new( file => $file );
1318 $self->_error( qq[Unable to add file: '$file'] );
1325 push @{$self->{_data}}, @rv;
1330 =head2 $tar->add_data ( $filename, $data, [$opthashref] )
1332 Takes a filename, a scalar full of data and optionally a reference to
1333 a hash with specific options.
1335 Will add a file to the in-memory archive, with name C<$filename> and
1336 content C<$data>. Specific properties can be set using C<$opthashref>.
1337 The following list of properties is supported: name, size, mtime
1338 (last modified date), mode, uid, gid, linkname, uname, gname,
1339 devmajor, devminor, prefix, type. (On MacOS, the file's path and
1340 modification times are converted to Unix equivalents.)
1342 Valid values for the file type are the following constants defined in
1343 Archive::Tar::Constants:
1355 Hard and symbolic ("soft") links; linkname should specify target.
1361 Character and block devices. devmajor and devminor should specify the major
1362 and minor device numbers.
1378 Returns the C<Archive::Tar::File> object that was just added, or
1379 C<undef> on failure.
1385 my ($file, $data, $opt) = @_;
1387 my $obj = Archive::Tar::File->new( data => $file, $data, $opt );
1389 $self->_error( qq[Unable to add file: '$file'] );
1393 push @{$self->{_data}}, $obj;
1398 =head2 $tar->error( [$BOOL] )
1400 Returns the current errorstring (usually, the last error reported).
1401 If a true value was specified, it will give the C<Carp::longmess>
1402 equivalent of the error, in effect giving you a stacktrace.
1404 For backwards compatibility, this error is also available as
1405 C<$Archive::Tar::error> although it is much recommended you use the
1406 method call instead.
1416 my $msg = $error = shift;
1417 $longmess = Carp::longmess($error);
1419 ### set Archive::Tar::WARN to 0 to disable printing
1422 carp $DEBUG ? $longmess : $msg;
1430 return shift() ? $longmess : $error;
1434 =head2 $tar->setcwd( $cwd );
1436 C<Archive::Tar> needs to know the current directory, and it will run
1437 C<Cwd::cwd()> I<every> time it extracts a I<relative> entry from the
1438 tarfile and saves it in the file system. (As of version 1.30, however,
1439 C<Archive::Tar> will use the speed optimization described below
1440 automatically, so it's only relevant if you're using C<extract_file()>).
1442 Since C<Archive::Tar> doesn't change the current directory internally
1443 while it is extracting the items in a tarball, all calls to C<Cwd::cwd()>
1444 can be avoided if we can guarantee that the current directory doesn't
1445 get changed externally.
1447 To use this performance boost, set the current directory via
1450 $tar->setcwd( cwd() );
1452 once before calling a function like C<extract_file> and
1453 C<Archive::Tar> will use the current directory setting from then on
1454 and won't call C<Cwd::cwd()> internally.
1456 To switch back to the default behaviour, use
1458 $tar->setcwd( undef );
1460 and C<Archive::Tar> will call C<Cwd::cwd()> internally again.
1462 If you're using C<Archive::Tar>'s C<exract()> method, C<setcwd()> will
1471 $self->{cwd} = $cwd;
1474 =head2 $bool = $tar->has_io_string
1476 Returns true if we currently have C<IO::String> support loaded.
1478 Either C<IO::String> or C<perlio> support is needed to support writing
1479 stringified archives. Currently, C<perlio> is the preferred method, if
1482 See the C<GLOBAL VARIABLES> section to see how to change this preference.
1486 sub has_io_string { return $HAS_IO_STRING; }
1488 =head2 $bool = $tar->has_perlio
1490 Returns true if we currently have C<perlio> support loaded.
1492 This requires C<perl-5.8> or higher, compiled with C<perlio>
1494 Either C<IO::String> or C<perlio> support is needed to support writing
1495 stringified archives. Currently, C<perlio> is the preferred method, if
1498 See the C<GLOBAL VARIABLES> section to see how to change this preference.
1502 sub has_perlio { return $HAS_PERLIO; }
1505 =head1 Class Methods
1507 =head2 Archive::Tar->create_archive($file, $compressed, @filelist)
1509 Creates a tar file from the list of files provided. The first
1510 argument can either be the name of the tar file to create or a
1511 reference to an open file handle (e.g. a GLOB reference).
1513 The second argument is used to indicate compression. You can either
1514 compress using C<gzip> or C<bzip2>. If you pass a digit, it's assumed
1515 to be the C<gzip> compression level (between 1 and 9), but the use of
1516 constants is prefered:
1518 # write a gzip compressed file
1519 Archive::Tar->create_archive( 'out.tgz', COMPRESSION_GZIP, @filelist );
1521 # write a bzip compressed file
1522 Archive::Tar->create_archive( 'out.tbz', COMPRESSION_BZIP, @filelist );
1524 Note that when you pass in a filehandle, the compression argument
1525 is ignored, as all files are printed verbatim to your filehandle.
1526 If you wish to enable compression with filehandles, use an
1527 C<IO::Zlib> or C<IO::Compress::Bzip2> filehandle instead.
1529 The remaining arguments list the files to be included in the tar file.
1530 These files must all exist. Any files which don't exist or can't be
1531 read are silently ignored.
1533 If the archive creation fails for any reason, C<create_archive> will
1534 return false. Please use the C<error> method to find the cause of the
1537 Note that this method does not write C<on the fly> as it were; it
1538 still reads all the files into memory before writing out the archive.
1539 Consult the FAQ below if this is a problem.
1543 sub create_archive {
1546 my $file = shift; return unless defined $file;
1547 my $gzip = shift || 0;
1551 return $class->_error( qq[Cowardly refusing to create empty archive!] );
1554 my $tar = $class->new;
1555 $tar->add_files( @files );
1556 return $tar->write( $file, $gzip );
1559 =head2 Archive::Tar->iter( $filename, [ $compressed, {opt => $val} ] )
1561 Returns an iterator function that reads the tar file without loading
1562 it all in memory. Each time the function is called it will return the
1563 next file in the tarball. The files are returned as
1564 C<Archive::Tar::File> objects. The iterator function returns the
1565 empty list once it has exhausted the the files contained.
1567 The second argument can be a hash reference with options, which are
1568 identical to the arguments passed to C<read()>.
1572 my $next = Archive::Tar->iter( "example.tar.gz", 1, {filter => qr/\.pm$/} );
1574 while( my $f = $next->() ) {
1575 print $f->name, "\n";
1577 $f->extract or warn "Extraction failed";
1587 my $filename = shift or return;
1588 my $compressed = shift or 0;
1589 my $opts = shift || {};
1591 ### get a handle to read from.
1592 my $handle = $class->_get_handle(
1600 return shift(@data) if @data; # more than one file returned?
1601 return unless $handle; # handle exhausted?
1603 ### read data, should only return file
1604 @data = @{ $class->_read_tar($handle, { %$opts, limit => 1 }) };
1606 ### return one piece of data
1607 return shift(@data) if @data;
1609 ### data is exhausted, free the filehandle
1615 =head2 Archive::Tar->list_archive($file, $compressed, [\@properties])
1617 Returns a list of the names of all the files in the archive. The
1618 first argument can either be the name of the tar file to list or a
1619 reference to an open file handle (e.g. a GLOB reference).
1621 If C<list_archive()> is passed an array reference as its third
1622 argument it returns a list of hash references containing the requested
1623 properties of each file. The following list of properties is
1624 supported: full_path, name, size, mtime (last modified date), mode,
1625 uid, gid, linkname, uname, gname, devmajor, devminor, prefix.
1627 See C<Archive::Tar::File> for details about supported properties.
1629 Passing an array reference containing only one element, 'name', is
1630 special cased to return a list of names rather than a list of hash
1637 my $file = shift; return unless defined $file;
1638 my $gzip = shift || 0;
1640 my $tar = $class->new($file, $gzip);
1643 return $tar->list_files( @_ );
1646 =head2 Archive::Tar->extract_archive($file, $compressed)
1648 Extracts the contents of the tar file. The first argument can either
1649 be the name of the tar file to create or a reference to an open file
1650 handle (e.g. a GLOB reference). All relative paths in the tar file will
1651 be created underneath the current working directory.
1653 C<extract_archive> will return a list of files it extracted.
1654 If the archive extraction fails for any reason, C<extract_archive>
1655 will return false. Please use the C<error> method to find the cause
1660 sub extract_archive {
1662 my $file = shift; return unless defined $file;
1663 my $gzip = shift || 0;
1665 my $tar = $class->new( ) or return;
1667 return $tar->read( $file, $gzip, { extract => 1 } );
1670 =head2 Archive::Tar->can_handle_compressed_files
1672 A simple checking routine, which will return true if C<Archive::Tar>
1673 is able to uncompress compressed archives on the fly with C<IO::Zlib>
1674 and C<IO::Compress::Bzip2> or false if not both are installed.
1676 You can use this as a shortcut to determine whether C<Archive::Tar>
1677 will do what you think before passing compressed archives to its
1682 sub can_handle_compressed_files { return ZLIB && BZIP ? 1 : 0 }
1684 sub no_string_support {
1685 croak("You have to install IO::String to support writing archives to strings");
1692 =head1 GLOBAL VARIABLES
1694 =head2 $Archive::Tar::FOLLOW_SYMLINK
1696 Set this variable to C<1> to make C<Archive::Tar> effectively make a
1697 copy of the file when extracting. Default is C<0>, which
1698 means the symlink stays intact. Of course, you will have to pack the
1699 file linked to as well.
1701 This option is checked when you write out the tarfile using C<write>
1702 or C<create_archive>.
1704 This works just like C</bin/tar>'s C<-h> option.
1706 =head2 $Archive::Tar::CHOWN
1708 By default, C<Archive::Tar> will try to C<chown> your files if it is
1709 able to. In some cases, this may not be desired. In that case, set
1710 this variable to C<0> to disable C<chown>-ing, even if it were
1713 The default is C<1>.
1715 =head2 $Archive::Tar::CHMOD
1717 By default, C<Archive::Tar> will try to C<chmod> your files to
1718 whatever mode was specified for the particular file in the archive.
1719 In some cases, this may not be desired. In that case, set this
1720 variable to C<0> to disable C<chmod>-ing.
1722 The default is C<1>.
1724 =head2 $Archive::Tar::DO_NOT_USE_PREFIX
1726 By default, C<Archive::Tar> will try to put paths that are over
1727 100 characters in the C<prefix> field of your tar header, as
1728 defined per POSIX-standard. However, some (older) tar programs
1729 do not implement this spec. To retain compatibility with these older
1730 or non-POSIX compliant versions, you can set the C<$DO_NOT_USE_PREFIX>
1731 variable to a true value, and C<Archive::Tar> will use an alternate
1732 way of dealing with paths over 100 characters by using the
1733 C<GNU Extended Header> feature.
1735 Note that clients who do not support the C<GNU Extended Header>
1736 feature will not be able to read these archives. Such clients include
1737 tars on C<Solaris>, C<Irix> and C<AIX>.
1739 The default is C<0>.
1741 =head2 $Archive::Tar::DEBUG
1743 Set this variable to C<1> to always get the C<Carp::longmess> output
1744 of the warnings, instead of the regular C<carp>. This is the same
1745 message you would get by doing:
1751 =head2 $Archive::Tar::WARN
1753 Set this variable to C<0> if you do not want any warnings printed.
1754 Personally I recommend against doing this, but people asked for the
1755 option. Also, be advised that this is of course not threadsafe.
1759 =head2 $Archive::Tar::error
1761 Holds the last reported error. Kept for historical reasons, but its
1762 use is very much discouraged. Use the C<error()> method instead:
1764 warn $tar->error unless $tar->extract;
1766 =head2 $Archive::Tar::INSECURE_EXTRACT_MODE
1768 This variable indicates whether C<Archive::Tar> should allow
1769 files to be extracted outside their current working directory.
1771 Allowing this could have security implications, as a malicious
1772 tar archive could alter or replace any file the extracting user
1773 has permissions to. Therefor, the default is to not allow
1774 insecure extractions.
1776 If you trust the archive, or have other reasons to allow the
1777 archive to write files outside your current working directory,
1778 set this variable to C<true>.
1780 Note that this is a backwards incompatible change from version
1783 =head2 $Archive::Tar::HAS_PERLIO
1785 This variable holds a boolean indicating if we currently have
1786 C<perlio> support loaded. This will be enabled for any perl
1787 greater than C<5.8> compiled with C<perlio>.
1789 If you feel strongly about disabling it, set this variable to
1790 C<false>. Note that you will then need C<IO::String> installed
1791 to support writing stringified archives.
1793 Don't change this variable unless you B<really> know what you're
1796 =head2 $Archive::Tar::HAS_IO_STRING
1798 This variable holds a boolean indicating if we currently have
1799 C<IO::String> support loaded. This will be enabled for any perl
1800 that has a loadable C<IO::String> module.
1802 If you feel strongly about disabling it, set this variable to
1803 C<false>. Note that you will then need C<perlio> support from
1804 your perl to be able to write stringified archives.
1806 Don't change this variable unless you B<really> know what you're
1813 =item What's the minimum perl version required to run Archive::Tar?
1815 You will need perl version 5.005_03 or newer.
1817 =item Isn't Archive::Tar slow?
1819 Yes it is. It's pure perl, so it's a lot slower then your C</bin/tar>
1820 However, it's very portable. If speed is an issue, consider using
1821 C</bin/tar> instead.
1823 =item Isn't Archive::Tar heavier on memory than /bin/tar?
1825 Yes it is, see previous answer. Since C<Compress::Zlib> and therefore
1826 C<IO::Zlib> doesn't support C<seek> on their filehandles, there is little
1827 choice but to read the archive into memory.
1828 This is ok if you want to do in-memory manipulation of the archive.
1830 If you just want to extract, use the C<extract_archive> class method
1831 instead. It will optimize and write to disk immediately.
1833 Another option is to use the C<iter> class method to iterate over
1834 the files in the tarball without reading them all in memory at once.
1836 =item Can you lazy-load data instead?
1838 In some cases, yes. You can use the C<iter> class method to iterate
1839 over the files in the tarball without reading them all in memory at once.
1841 =item How much memory will an X kb tar file need?
1843 Probably more than X kb, since it will all be read into memory. If
1844 this is a problem, and you don't need to do in memory manipulation
1845 of the archive, consider using the C<iter> class method, or C</bin/tar>
1848 =item What do you do with unsupported filetypes in an archive?
1850 C<Unix> has a few filetypes that aren't supported on other platforms,
1851 like C<Win32>. If we encounter a C<hardlink> or C<symlink> we'll just
1852 try to make a copy of the original file, rather than throwing an error.
1854 This does require you to read the entire archive in to memory first,
1855 since otherwise we wouldn't know what data to fill the copy with.
1856 (This means that you cannot use the class methods, including C<iter>
1857 on archives that have incompatible filetypes and still expect things
1860 For other filetypes, like C<chardevs> and C<blockdevs> we'll warn that
1861 the extraction of this particular item didn't work.
1863 =item I'm using WinZip, or some other non-POSIX client, and files are not being extracted properly!
1865 By default, C<Archive::Tar> is in a completely POSIX-compatible
1866 mode, which uses the POSIX-specification of C<tar> to store files.
1867 For paths greather than 100 characters, this is done using the
1868 C<POSIX header prefix>. Non-POSIX-compatible clients may not support
1869 this part of the specification, and may only support the C<GNU Extended
1870 Header> functionality. To facilitate those clients, you can set the
1871 C<$Archive::Tar::DO_NOT_USE_PREFIX> variable to C<true>. See the
1872 C<GLOBAL VARIABLES> section for details on this variable.
1874 Note that GNU tar earlier than version 1.14 does not cope well with
1875 the C<POSIX header prefix>. If you use such a version, consider setting
1876 the C<$Archive::Tar::DO_NOT_USE_PREFIX> variable to C<true>.
1878 =item How do I extract only files that have property X from an archive?
1880 Sometimes, you might not wish to extract a complete archive, just
1881 the files that are relevant to you, based on some criteria.
1883 You can do this by filtering a list of C<Archive::Tar::File> objects
1884 based on your criteria. For example, to extract only files that have
1885 the string C<foo> in their title, you would use:
1888 grep { $_->full_path =~ /foo/ } $tar->get_files
1891 This way, you can filter on any attribute of the files in the archive.
1892 Consult the C<Archive::Tar::File> documentation on how to use these
1895 =item How do I access .tar.Z files?
1897 The C<Archive::Tar> module can optionally use C<Compress::Zlib> (via
1898 the C<IO::Zlib> module) to access tar files that have been compressed
1899 with C<gzip>. Unfortunately tar files compressed with the Unix C<compress>
1900 utility cannot be read by C<Compress::Zlib> and so cannot be directly
1901 accesses by C<Archive::Tar>.
1903 If the C<uncompress> or C<gunzip> programs are available, you can use
1904 one of these workarounds to read C<.tar.Z> files from C<Archive::Tar>
1906 Firstly with C<uncompress>
1910 open F, "uncompress -c $filename |";
1911 my $tar = Archive::Tar->new(*F);
1914 and this with C<gunzip>
1918 open F, "gunzip -c $filename |";
1919 my $tar = Archive::Tar->new(*F);
1922 Similarly, if the C<compress> program is available, you can use this to
1923 write a C<.tar.Z> file
1928 my $fh = new IO::File "| compress -c >$filename";
1929 my $tar = Archive::Tar->new();
1934 =item How do I handle Unicode strings?
1936 C<Archive::Tar> uses byte semantics for any files it reads from or writes
1937 to disk. This is not a problem if you only deal with files and never
1938 look at their content or work solely with byte strings. But if you use
1939 Unicode strings with character semantics, some additional steps need
1942 For example, if you add a Unicode string like
1945 $tar->add_data('file.txt', "Euro: \x{20AC}");
1947 then there will be a problem later when the tarfile gets written out
1948 to disk via C<$tar->write()>:
1950 Wide character in print at .../Archive/Tar.pm line 1014.
1952 The data was added as a Unicode string and when writing it out to disk,
1953 the C<:utf8> line discipline wasn't set by C<Archive::Tar>, so Perl
1954 tried to convert the string to ISO-8859 and failed. The written file
1955 now contains garbage.
1957 For this reason, Unicode strings need to be converted to UTF-8-encoded
1958 bytestrings before they are handed off to C<add_data()>:
1961 my $data = "Accented character: \x{20AC}";
1962 $data = encode('utf8', $data);
1964 $tar->add_data('file.txt', $data);
1966 A opposite problem occurs if you extract a UTF8-encoded file from a
1967 tarball. Using C<get_content()> on the C<Archive::Tar::File> object
1968 will return its content as a bytestring, not as a Unicode string.
1970 If you want it to be a Unicode string (because you want character
1971 semantics with operations like regular expression matching), you need
1972 to decode the UTF8-encoded content and have Perl convert it into
1976 my $data = $tar->get_content();
1978 # Make it a Unicode string
1979 $data = decode('utf8', $data);
1981 There is no easy way to provide this functionality in C<Archive::Tar>,
1982 because a tarball can contain many files, and each of which could be
1983 encoded in a different way.
1991 =item Check if passed in handles are open for read/write
1993 Currently I don't know of any portable pure perl way to do this.
1994 Suggestions welcome.
1996 =item Allow archives to be passed in as string
1998 Currently, we only allow opened filehandles or filenames, but
1999 not strings. The internals would need some reworking to facilitate
2000 stringified archives.
2002 =item Facilitate processing an opened filehandle of a compressed archive
2004 Currently, we only support this if the filehandle is an IO::Zlib object.
2005 Environments, like apache, will present you with an opened filehandle
2006 to an uploaded file, which might be a compressed archive.
2014 =item The GNU tar specification
2016 C<http://www.gnu.org/software/tar/manual/tar.html>
2018 =item The PAX format specication
2020 The specifcation which tar derives from; C< http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html>
2022 =item A comparison of GNU and POSIX tar standards; C<http://www.delorie.com/gnu/docs/tar/tar_114.html>
2024 =item GNU tar intends to switch to POSIX compatibility
2026 GNU Tar authors have expressed their intention to become completely
2027 POSIX-compatible; C<http://www.gnu.org/software/tar/manual/html_node/Formats.html>
2029 =item A Comparison between various tar implementations
2031 Lists known issues and incompatibilities; C<http://gd.tuwien.ac.at/utils/archivers/star/README.otherbugs>
2037 This module by Jos Boumans E<lt>kane@cpan.orgE<gt>.
2039 Please reports bugs to E<lt>bug-archive-tar@rt.cpan.orgE<gt>.
2041 =head1 ACKNOWLEDGEMENTS
2043 Thanks to Sean Burke, Chris Nandor, Chip Salzenberg, Tim Heaney, Gisle Aas
2044 and especially Andrew Savige for their help and suggestions.
2048 This module is copyright (c) 2002 - 2007 Jos Boumans
2049 E<lt>kane@cpan.orgE<gt>. All rights reserved.
2051 This library is free software; you may redistribute and/or modify
2052 it under the same terms as Perl itself.