From: "Tom Demmer" <DEMMER AT brain1 DOT lstm DOT ruhr-uni-bochum DOT de>
Organization:  Lehrstuhl Stroemungsmechanik, RUB
To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>, djgpp AT delorie DOT com
Date:          Tue, 5 May 1998 10:56:17 GMT-1
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Subject:       Re: fixpath problem in Novell drives.
Reply-to: Demmer AT LStM DOT Ruhr-Uni-Bochum DOT De
Message-ID: <961B9986273@brain1.lstm.ruhr-uni-bochum.de>
Precedence: bulk

> 
> On Tue, 5 May 1998, Thomas Demmer wrote:
> 
> > Hmm, this can easily fail on a redirected network drive. 
> > Under Novell, I can do nasty things as
> > 
> > MAP ROOT i:=usr:home/demmer/djgpp
> > MAP ROOT k:=usr:home/demmer/djgpp/bin
> > cp i:/bin/gcc.exe k:/gcc.exe
> > 
> > and end up with a nuked gcc.exe, because both names refer to the
> > same file. stat() will happily report both of them being
> > different files, when in fact they are the same. IIRC, stat()
> > keeps track of filenames on a drive level to invent inodes.
> 
> Did you actually try this?  If so, I would like to hear the results.

These commands

MAP ROOT L:=i:\demmer
MAP ROOT K:=i:\demmer\tmp
K:
cp turboc.cfg l:/tmp

yield:
No warning,
turboc.cfg truncated to length zero.

cp --v
  cp - GNU Fileutils-3.13

Hmm, is this still up to date?

However, 
copy turboc.cfg l:\tmp
gives the error
File cannot be copied to itself. 


> 
> As far as I know, on DOS and Windows 3.X, the above would correctly tell 
> you that these files are the same, because `_truename' resolves both names 
> to the same UNC, and thus both files get the same inode and the same 
> st_dev number.  The same situation exists with SUBST and JOIN, and `stat' 
> does handles those correctly.

I can confirm this. Both say
\\BRAIN1\USR\HOME\DEMMER\TMP\TURBOC.CFG



>
> 
> The only place where this does break is on Windows 9X (surprise, 
> surprise!).  It turns out that Windows doesn't care to return a UNC for 
> drives mapped to other machines in the workgroup, so you get the same 
> X:\foo back, even if X: is actually mapped to \\TOM_DEMMER\SHARE\LIB.  I 
> had an experimental version of `stat' which tried to resolve this by 
> fetching the network name of X:, but then I found out that in some cases 
> this doesn't work either, so I abandoned the idea, for now.
> 
> > The concept of drive letters is so brain-dead that it hurts,
> > but what can you do?
> 
> First, you can avoid mapping different drive letters to the same disk on 
> the same machine.  (Remember that "don't do that" joke?)

I do know what I am doing (read: I can sometimes figure out what went 
wrong when I didn't know what I was doing), but some of the users 
here cannot.

> 
> And second, you could yell at Microsoft gods to return the UNC like we 
> all expect.
> 
I admire your faith. Did that _ever_ help? ;-)

And third, switch to a working OS.


Ciao

Tom

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    Naeser's Law: You can make it foolproof, but you can't make it
                  damnfoolproof.