Re: Should hard links to directories work?

[Gary Thomas <gary@mlbassoc.com>]

Bart Veer wrote:
>>>>>> "Ross" == Ross Younger <wry@ecoscentric.com> writes:
> 
>     Ross> The Unix world traditionally shuns such things as an
>     Ross> abomination. The eCos docs are quiet on the subject, as is
>     Ross> the code in ramfs and jffs2. Should they work? Does anybody
>     Ross> use them?
> 
>     Ross> (By the way: I started this discussion with a bugzilla
>     Ross> ticket, which as Andrew points out is probably the wrong
>     Ross> place.
>     Ross> http://bugzilla.ecoscentric.com/show_bug.cgi?id=1000775 )
> 
>From http://www.opengroup.org/onlinepubs/7990989775/xsh/link.html:
> 
>   "The link() function creates a new link (directory entry) for the
>   existing file, path1.
> 
>   The path1 argument points to a pathname naming an existing file. The
>   path2 argument points to a pathname naming the new directory entry
>   to be created. The link() function will atomically create a new link
>   for the existing file and the link count of the file is incremented
>   by one.
> 
>   If path1 names a directory, link() will fail unless the process has
>   appropriate privileges and the implementation supports using link()
>   on directories."
> 
> So creating links to directories is not completely disallowed, but
> from my reading it is certainly discouraged. I would be happy with
> changes to ramfs and jffs2 to prevent new links to directories.
> jffs2 should probably continue to support such links in an existing
> filesystem, in case they are created in another OS.

What about "./." and "./.."?  Those must certainly be allowed.

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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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