On 20-nov-03, at 13:00, Guest via RT wrote:
Show quoted text> An archive created by Archive::Tar does not create entries for
> leading directories. Those archives are handled alright by recent
> tar programs, but have problems with older BSD tar programs.
Although probably true, this is wholly and totally to blame on the
older BSD tar programs, as they simply do not follow the tar spec.
Instead, they choose to ignore
the 'prefix' field in the tar header, or more accurately, are so old
they are not
aware this field exists...
From:
http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html
"The name and the prefix fields shall produce the pathname of the file.
A new pathname shall be formed, if prefix is not an empty string (its
first character is not NUL), by concatenating prefix (up to the first
NUL character), a slash character, and name; otherwise, name is used
alone. In either case, name is terminated at the first NUL character.
If prefix begins with a NUL character, it shall be ignored. In this
manner, pathnames of at most 256 characters can be supported. If a
pathname does not fit in the space provided, pax shall notify the user
of the error, and shall not store any part of the file-header or
data-on the medium."
it's amended with:
"The total size of the name and prefix fields have been set to meet the
minimum requirements for {PATH_MAX}. If a pathname will fit within the
name field, it is recommended that the pathname be stored there without
the use of the prefix field. Although the name field is known to be too
small to contain {PATH_MAX} characters, the value was not changed in
this version of the archive file format to retain
backwards-compatibility, and instead the prefix was introduced. Also,
because of the earlier version of the format, there is no way to remove
the restriction on the linkname field being limited in size to just
that of the name field."
The solution Archive::Tar implements is a 'rather safe than sorry'
solution, which tries to split out dirs from names to avoid having to
deal with how paths are exactly built up.
Anything going over the 255 byte length that the headers allows for, is
put in an extended header (the ././@LongLink entries -- which postdates
even the 'prefix' addition).
Allowing to be totally compatible with 'older' tars, it would mean that
Archive::Tar could not deal with any files longer than a 100 characters
(since that's the number of bytes in the header allocated for the
'name' field), which is an even more undesirable solution i think.
Below the sig is a program that demonstrates what i mean...
Sadly, the only course of action that can be taken here is to upgrade
to versions of tar/gtar that adhere to the current format spec.
--
Jos Boumans
"You know you are never more indignant in life than when you're
shopping at a store you feel is beneath you and one of the other
customers mistakes you for one of the employees of that store."
- Dennis Miller
CPANPLUS
http://cpanplus.sf.net
[kane@coke ~...tmp/leading-dir-bug]$ cat x.pl
use Archive::Tar;
use Data::Dumper;
use strict;
my $file = shift;
my $glob = shift;
Archive::Tar->create_archive($file,0,glob($glob)) or die
Archive::Tar->error;
my $tar = Archive::Tar->new($file);
print Dumper $_ for $tar->get_files;
[kane@coke ~...tmp/leading-dir-bug]$ perlc x.pl test.tar
"/Users/kane/p4/other/archive-tar-new/tmp/leading-dir-bug/foo/*"
$VAR1 = bless( {
'mode' => 33188,
'linkname' => '',
'gid' => 502,
'magic' => 'ustar',
'data' => '',
'name' =>
'Users/kane/p4/other/archive-tar-new/tmp/leading-dir-bug/foo/a',
'mtime' => 1069695358,
'size' => 0,
'uid' => 502,
'version' => '00',
'raw' => 'a100644000766000766 0 7760440576
23236
0ustar00kanekane000000000000Users/kane/p4/other/archive-tar-new/tmp/
leading-dir-bug/foo',
'type' => '0',
'uname' => 'kane',
'devmajor' => 0,
'devminor' => 0,
'prefix' =>
'Users/kane/p4/other/archive-tar-new/tmp/leading-dir-bug/foo',
'chksum' => 9886,
'gname' => 'kane'
}, 'Archive::Tar::File' );
$VAR1 = bless( {
'mode' => 33188,
'linkname' => '',
'gid' => 502,
'magic' => 'ustar',
'data' => '',
'name' =>
'Users/kane/p4/other/archive-tar-new/tmp/leading-dir-bug/foo/b',
'mtime' => 1069695358,
'size' => 0,
'uid' => 502,
'version' => '00',
'raw' => 'b100644000766000766 0 7760440576
23237
0ustar00kanekane000000000000Users/kane/p4/other/archive-tar-new/tmp/
leading-dir-bug/foo',
'type' => '0',
'uname' => 'kane',
'devmajor' => 0,
'devminor' => 0,
'prefix' =>
'Users/kane/p4/other/archive-tar-new/tmp/leading-dir-bug/foo',
'chksum' => 9887,
'gname' => 'kane'
}, 'Archive::Tar::File' );
$VAR1 = bless( {
'mode' => 33188,
'linkname' => '',
'gid' => 502,
'magic' => 'ustar',
'data' => '',
'name' =>
'Users/kane/p4/other/archive-tar-new/tmp/leading-dir-bug/foo/c',
'mtime' => 1069695358,
'size' => 0,
'uid' => 502,
'version' => '00',
'raw' => 'c100644000766000766 0 7760440576
23240
0ustar00kanekane000000000000Users/kane/p4/other/archive-tar-new/tmp/
leading-dir-bug/foo',
'type' => '0',
'uname' => 'kane',
'devmajor' => 0,
'devminor' => 0,
'prefix' =>
'Users/kane/p4/other/archive-tar-new/tmp/leading-dir-bug/foo',
'chksum' => 9888,
'gname' => 'kane'
}, 'Archive::Tar::File' );
