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Re: Should hard links to directories work?
- From: Gary Thomas <gary at mlbassoc dot com>
- To: Bart Veer <bartv at ecoscentric dot com>
- Cc: Ross Younger <wry at ecoscentric dot com>, ecos-devel at ecos dot sourceware dot org
- Date: Wed, 20 May 2009 07:52:04 -0600
- Subject: Re: Should hard links to directories work?
- References: <4A13F762.4050006@ecoscentric.com> <pnbppnanx2.fsf@delenn.bartv.net>
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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