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From: dave@murphy.UUCP (Dave Cornutt)
Newsgroups: comp.unix.wizards
Subject: Re: Symbolic Links
Message-ID: <586@murphy.UUCP>
Date: Fri, 28-Aug-87 08:23:43 EDT
Article-I.D.: murphy.586
Posted: Fri Aug 28 08:23:43 1987
Date-Received: Sun, 30-Aug-87 00:53:56 EDT
References: <8731@brl-adm.ARPA> <2789@ulysses.homer.nj.att.com> <1781@munnari.oz> <8195@mimsy.UUCP>
Organization: Gould CSD, Fort Lauderdale, FL
Lines: 32
Summary: (CAN YOU STAND TO READ ONE MORE ARTICLE ON THIS SUBJECT???)

Well, it appears that there is a large number of people in both camps.  I
happen to be one of the members of the "leave it alone" camp, but I've
already posted my feelings on this subject, and I don't feel like fanning
these flames any further.  So, instead, I'll offer a suggestion for how
such a thing could be implemented.

Do it on a per-process basis, perhaps using a bit in the process flags field.
When the flag is on, ".." behaves as the go-up operator; when it is off,
".." behaves as it does now.  When a process forks, have the child inherit
the setting of the bit from its parent.  The shells should have a variable
or something that, when set, turns the flag on, so that the shell (and
all of its children) behave in the new manner.  (Unsetting the variable
restores the old behavior for the shell and any subsequently created
children.)  Init should have the flag off, for backwards compatibility.
Processes which have the flag off should not have to carry the overhead of
the directory context structure.

How to change the state of the bit?  Well, if you don't feel like inventing
a new system call, you could use ulimit (SYSV) or setrlimit (BSD).  Actually,
the really spiffy way would be to implement /proc and have it be an ioctl,
but I think that's still a ways off from appearing in commercial products.
---
"I dare you to play this record" -- Ebn-Ozn

Dave Cornutt, Gould Computer Systems, Ft. Lauderdale, FL
[Ignore header, mail to these addresses]
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"The opinions expressed herein are not necessarily those of my employer,
not necessarily mine, and probably not necessary."