Re: hardlink to symlink behaviour [was: Re: MKXORG=yes on Linux: nbmtree: existing entry for `libXaw.so', type `link' does not match type `file']

[Adam Hoka <adam.hoka%gmail.com@localhost>]

Hubert Feyrer wrote:
> On Tue, 30 Sep 2008, Hubert Feyrer wrote:
> > nbmtree: existing entry for `libXaw.so', type `link' does not match 
> > type `file'
>
> Digging a bit more into this, it's related to the difference in handling 
> hardlink to symlinks. On NetBSD, it seems that you get a link to the 
> target file these days[1], while on Linux you get a link to the 
> symlink[2]. ISTR that NetBSD used to behave like Linux there - is this 
> really intended?
>
> FWIW, Solaris behaves the same way as Linux does.

Yes, both of them are "incorrect" (if you can use this term for not 
following all other unix systems). :)

See this for a vulnerability because of this misbehavior:
http://securitytracker.com/alerts/2008/Aug/1020700.html

>  - Hubert
>
>
> [1]    % set files="/tmp/f /tmp/lf /tmp/hlf" ; rm $files ; touch /tmp/f 
> ; ln -s /tmp/f /tmp/lf ; ln /tmp/lf /tmp/hlf ; perl -e 'foreach $f 
> (@ARGV) { @x=stat($f);printf "mode=%o for $f\n", $x[2]; }' $files ; ls 
> -lad $files
>     mode=100664 for /tmp/f
>     mode=100664 for /tmp/lf
>     mode=100664 for /tmp/hlf
>     -rw-rw-r--  2 feyrer  wheel  0 Sep 30 13:59 /tmp/f
>    ===>    -rw-rw-r--  2 feyrer  wheel  0 Sep 30 13:59 /tmp/hlf
>     lrwxrwxr-x  1 feyrer  wheel  6 Sep 30 13:59 /tmp/lf -> /tmp/f
>
>
> [2]    % set files="/tmp/f /tmp/lf /tmp/hlf" ; rm $files ; touch /tmp/f 
> ; ln -s /tmp/f /tmp/lf ; ln /tmp/lf /tmp/hlf ; perl -e 'foreach $f 
> (@ARGV) { @x=stat($f);printf "mode=%o for $f\n", $x[2]; }' $files ; ls 
> -lad $files
>     mode=100664 for /tmp/f
>     mode=100664 for /tmp/lf
>     mode=100664 for /tmp/hlf
>     -rw-rw-r-- 1 feyrer bedienst 0 Sep 30 13:59 /tmp/f
>    ===>    lrwxrwxrwx 2 feyrer bedienst 6 Sep 30 13:59 /tmp/hlf -> /tmp/f
>     lrwxrwxrwx 2 feyrer bedienst 6 Sep 30 13:59 /tmp/lf -> /tmp/f