Re: [Bug-tar] SIGPIPE problem and regression for tar 1.21 on Interix

[Martin Koeppe]

On Wed, 18 Feb 2009, Sergey Poznyakoff wrote:

> Martin Koeppe <address@hidden> ha escrit:

> > I'm using GNU tar on Interix. See http://www.debian-interix.net/
> > for more details.
> >
> > I encountered some .tar.gz files which I cannot extract correctly.
> > Most others work well. One of those failing files is:
> > http://ftp.de.debian.org/debian/pool/main/s/smstools/smstools_3.1.orig.tar.gz
> >
> > I get:
> >
> >   $ tar --version
> >   tar (GNU tar) 1.20
> >   Copyright (C) 2008 Free Software Foundation, Inc.
> >   License GPLv3+: GNU GPL version 3 or later
> >   <http://gnu.org/licenses/gpl.html>
> >   This is free software: you are free to change and redistribute it.
> >   There is NO WARRANTY, to the extent permitted by law.
> >
> >   Written by John Gilmore and Jay Fenlason.
> >
> >   $ tar xzf smstools_3.1.orig.tar.gz
> >   tar: Child died with signal 13
> >   tar: Error exit delayed from previous errors
> >
> > The archive gets extracted anyway, but tar fails. These ones both 
> > work, however:
> >
> >   $ gzip -d -c smstools_3.1.orig.tar.gz | tar xf -
> >   $ cat smstools_3.1.orig.tar.gz | tar xzf -
>
> I cannot reproduce it. What are your tar defaults (see tail of `tar
> --help' output)?

I have now narrowed down this issue. The best example now is the
Debian source for GNU tar. While I could successfully extract
  http://ftp.de.debian.org/debian/pool/main/t/tar/tar_1.20.orig.tar.gz
I cannot extract
  http://ftp.de.debian.org/debian/pool/main/t/tar/tar_1.22.orig.tar.gz
anymore. When gunzipping this tar_1.22.orig.tar.gz file, then one can 
see that more than 10k (20*512) bytes of zeros (actually there are 21 
512-byte blocks) are at the end of the uncompressed tar file.

Looking at the above mentioned smstools_3.1.orig.tar.gz also shows 21 
512-byte blocks of zeros at the end. I verified this for several other 
failing archives, too.

As this works on Linux, it's surely a portability issue. strace on 
Linux shows that the trailing zeros are read, while truss on Interix 
shows that they aren't. I would like to ask what part of tar might be 
responsible for this behaviour.

Martin