Path: utzoo!utgpu!attcan!uunet!husc6!cmcl2!rutgers!att!pacbell!rtech!gonzo!daveb
From: daveb@gonzo.UUCP (Dave Brower)
Newsgroups: comp.unix.wizards
Subject: Re: Reading directories (was: Re: directory copying with cp; broken?)
Message-ID: <438@gonzo.UUCP>
Date: 17 Oct 88 04:12:55 GMT
References: <30506@bbn.COM> <884@yabbie.rmit.oz> <331@talos.UUCP>
Reply-To: daveb@gonzo.UUCP (Dave Brower)
Organization: Gonzo Media Group
Lines: 20

In article <331@talos.UUCP> kjones@talos.UUCP (Kyle Jones) writes:
>In article <884@yabbie.rmit.oz> rcodi@yabbie.rmit.oz (Ian Donaldson) writes:
>>So what's the problem with disallowing opening directory special files 
>>generally?
>
>It violates the UNIX principle of `a file is a file is a file...'.  It
>is clear why directories should not be arbitrarily writable but I
>don't see any such reason why they shouldn't be readable.  The portable
>directory reading routines could use the existing read(2) system call,
>instead of adding (yet another) system call just to read directories.

The problem that is fixed by having system call directory access rather
than plain ol' read(2) is this:  What do you do when you have a
filesystem  type, presumably imported from some other OS, where
directories are *not* just files?  This struck the folks at AT&T like a
bullet when they introduced the files system switch (FSS) in V.3 (or was
it V.2?).  In particular, it is what would let you mount a VMS file
system and still be able to read the directories.

-dB