Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!snorkelwacker!mit-eddie!aryeh
From: aryeh@eddie.mit.edu (Aryeh M. Weiss)
Newsgroups: comp.unix.wizards
Subject: Re: Hard links to directories: why not?
Keywords: ln, directories, security...
Message-ID: <1990Jul23.132628.24737@eddie.mit.edu>
Date: 23 Jul 90 13:26:28 GMT
References: <5222@milton.u.washington.edu> <6940@eos.UUCP> <1990Jul19.115622.14015@mips2.cr.bull.com> <11070@alice.UUCP> <9007221600.AA00202@mindcrf.mindcraft.com>
Reply-To: aryeh@eddie.MIT.EDU (Aryeh M. Weiss)
Organization: MIT EE/CS Computer Facilities, Cambridge, MA
Lines: 15

In article <9007221600.AA00202@mindcrf.mindcraft.com> karish@mindcrf.UUCP writes:
>In article <11070@alice.UUCP> andrew@alice.UUCP (Andrew Hume) writes:
>
>    Links to files don't `bugger' the file system's structure,
>    because they don't create loops that make tree traversal
>    ambiguous.  It's still a tree, with some leaves fused
>    together.
>

Why can't potential loops be detected when a hard link request is given?
I.e., if I request to link directory `a' to directory `b', the
kernal could look up the tree to see if `a' already occurs as a parent
to `b', and deny the request if it does (ELOOPDEELOOP).

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