Date: Sun, 7 Aug 2011 22:55:39 -0700 From: Tim Kientzle <tim@kientzle.com> To: Bruce Cran <bruce@cran.org.uk> Cc: Test Rat <ttsestt@gmail.com>, freebsd-current@freebsd.org, Martin Matuska <mm@freebsd.org> Subject: Re: bsdtar(1) can't extract new ISO images Message-ID: <A4BF47D9-FB90-42A0-961A-16F0EE6FBC72@kientzle.com> In-Reply-To: <4E3EBBE4.9080604@cran.org.uk> References: <86hb5yaav0.fsf@gmail.com> <4E3D73B9.7090406@FreeBSD.org> <4E3EBBE4.9080604@cran.org.uk>
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On Aug 7, 2011, at 9:23 AM, Bruce Cran wrote: > On 06/08/2011 18:02, Martin Matuska wrote: >> The error is in FreeBSD ISO images. >> They are created using makefs and that doesn't create ISO files that >> strictly comple to the ECMA-119 (ISO9660 standard). >>=20 >> I have already filed a PR at NetBSD (bin/45217): >> http://gnats.netbsd.org/cgi-bin/query-pr-single.pl?number=3D45217 >>=20 >> The volume_set_id doesn't have to be filled with 0x20 characters, = too. >> I am also preparing a patch for libarchive (different things), but = that >> won't fix that one bug - makefs needs to be fixed. >=20 > Thanks for the information - I suspect this is also the problem I saw = a few weeks ago on OS X Lion when trying to extract an ISO of Windows = Server 2003 R2: >=20 > neutrino:tmp brucec$ tar -xvf = en_win_srv_2003_r2_standard_with_sp2_cd2_X13-68583.iso > neutrino:tmp brucec$ echo $? > 0 >=20 > It would be nice if bsdtar exited with a non-zero code in this case. I agree, it would be nice. ISO images frequently begin with a large block of zero bytes that looks = exactly like a tar end-of-file marker. So if libarchive doesn't = recognize it as an ISO, it will often recognize the file as a valid = empty tar archive that has a bunch of garbage after the end-of-archive = marker. So it successfully extracts no files. This sort of problem should become less common as we continue to refine = the bidding heuristics used in libarchive. If you have ideas for = further improving them, I'm definitely interested. (At a minimum, I'm = always interested in seeing at least the first 32k or so of any file = that "tar -tvvvf" gives the wrong format for.) Tim
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