changing gzip's symlink handling to be consistent with bzip2, xz and GNU gzip

[Alexander Best]

On Mon Nov 15 10, Xin LI wrote:
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> Hi,
> 
> On 11/15/10 10:24, Alexander Best wrote:
> > hi there,
> > 
> > any thoughts on this patch? it changes the semantics of gzip so that it is
> > consistent with the semantics of bzip2, xz and for more important GNU gzip.
> 
> Could you please elaborate more about the GNU gzip behavior?

sure!

***START LINUX***
otaku% gzip --version
gzip 1.4
Copyright (C) 2007 Free Software Foundation, Inc.
Copyright (C) 1993 Jean-loup Gailly.
This is free software.  You may redistribute copies of it under the terms of
the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
There is NO WARRANTY, to the extent permitted by law.

Written by Jean-loup Gailly.
otaku% echo "AAAAA" > FILE1
otaku% ln -s FILE1 FILE2
otaku% gzip FILE2
gzip: FILE2: Too many links
otaku% gzip --force FILE2
otaku% file FILE2.gz 
FILE2.gz: gzip compressed data, was "FILE2", from Unix, last modified: Mon Nov 15 21:09:03 2010
***END LINUX***

***START BSD***
otaku% gzip --version
FreeBSD gzip 20100407
otaku% echo "AAAAA" > FILE1
otaku% ln -s FILE1 FILE2
otaku% gzip FILE2
otaku% file FILE2.gz 
FILE2.gz: gzip compressed data, was "FILE2", from Unix, last modified: Mon Nov 15 22:12:21 2010
**END BSD***

***START BSD WITH PATCH***
otaku% gzip --version
FreeBSD gzip 20100407
otaku% echo "AAAAA" > FILE1
otaku% ln -s FILE1 FILE2
otaku% gzip FILE2 
gzip: FILE2 is not a regular file
otaku% gzip --force FILE2
otaku% file FILE2.gz     
FILE2.gz: gzip compressed data, was "FILE2", from Unix, last modified: Mon Nov 15 22:17:11 2010
**END BSD WITH PATCH***

> 
> By the way I also found some difference between BSD gzip and GNU gzip:
> 
> touch foo
> ln -s foo.nonexistent foo.gz
> 
> gzip foo
> gzip: could not create output: foo.gz: File exists
> 
> /usr/local/bin/gzip foo
> gzip: foo.gz already exists; do you wish to overwrite (y or n)? ^C
> (case 1)
> 
> echo | /usr/local/bin/gzip foo
> gzip: foo.gz already exists;	not overwritten
> 
> gzip -f foo
> gzip: could not create output: foo.gz: File exists
> 
> /usr/local/bin/gzip -f foo
> (succeeded; case 2).
> 
> 
> Cheers,
> - -- 
> Xin LI <delphij at delphij.net>	http://www.delphij.net/
> FreeBSD - The Power to Serve!	       Live free or die
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-- 
a13x