Automounter Question - Summary & Thanks

From: ames!claris!voder!nsc!taux01.nsc.com!amir@umiacs.UMD.EDU
Date: Thu May 16 1991 - 14:09:03 CDT


- A Few days ago I posted an automounter-related question (see below)
  and I have been flooded with answers.
- Thanks for all those who answered so far.
- I'll summarize below. I tried to reply to each person, but some mails bounced,
  so I'll honor all of them below.
- I apologize again for putting a 'tar'-realted question on sun-nets.
- BTW, only one person (so far) has answered question 2 below (antwerp@tpdsun.tno.nl) -
  He says it can be done.

------------------- the question: --------------------

I have a tar tape (a poor copy of MIT X11R4) which was prepared in the dumbest way possible:
(well, maybe there are dumber ways, but I have not seen them yet...)

$ tar tvf /dev/rst8
r--r--r--603/603 214 Dec 21 00:06 1989 /net/hostile/mit/CHANGES
rw-rw-r--603/603 53362 Dec 24 00:21 1989 /net/hostile/mit/CHANGES.ALL
[...and so it goes...]

Needless to say, I don't have a machine called 'hostile' in my net.

Previously I dealt with it by taking down the automounter, create a real
directory 'hostile' under /net and extract the stuff that I needed.

I was wondering whether I can fake a machine in the YP hosts map with the
above name, but with an ethernet address of my (real) machine and then create 'mit'
under the root and thus when extracting to /net/hostile it will actually go
to /net/friendly.

However, I'm loath to try it before I'm sure it'll work (a little wimpy, I admit).

My questions are:
1. Will it work?
2. Do YP/NFS/automounter care if there >1 host with the same address?
3. Unrelated to networking, is there a nicer way to override dump tar files like that?

------------------- the answers: --------------------

1. Use GNU's 'tar' - it strips leading '/' from archived file names.

    George Young young@vlsi.ll.mit.edu
    Hans Berggren hans@inmic.se
    ? osm@ox.com
    Bennett Todd bet@orion.mc.duke.edu
    Scott Schwartz schwartz@groucho.cs.psu.edu
    kevin ? kevin@saber.com
    Brian Baird baird@ucs.ubc.ca
    Brian Kelley brian@cimage.com
    Timothy G. Smith tgsmith@fedps.East.Sun.COM
    Roy Smith roy@alanine.phri.nyu.edu

2. Hack the output of tar:

   use 'pax' - David N. Blank dnb@meshugge.media.mit.edu
   use 'fixtar' - Wietse Venema wswietse@svbs01.bs.win.tue.nl

3. Unpack the archive under a different root, using 'chroot':

   Hans Buurman hans@duttnph.tudelft.nl
   Bob Drzyzgula rcd@fed.frb.gov

4. Set up symbolic links from /net/hostile to a real directory:

   Brent Chivers bchivers@mitre.org
   Keith McNeill eplrx7!mcneill@uunet.uu.net
   Gert van Antwerpen antwerp@tpdsun.tno.nl
   Steve Harris uunet!etnibsd!vsh

------------------- the verdict: --------------------

I tried GNU tar 1.08. It worked for a while, then crashed with 'bus error'.
I then opted for Hans Buurman's 'chroot' solution which worked like a charm.
It does require superuser permission.
I have tried neither setting up symbolic links nor 'pax' of 'fixtar'.

Thanks for all who responded and tell your friends never to use absolute
files names when using 'tar'.

   Amir J. Katz, System Manager

Internet: amir%pilat.UUCP@taux01.nsc.com
UUCP: {decwrl,uunet,...}!nsc!taux01!amir
Phone: +972 52-570713
Fax: +972 52-570719
Snail-mail: Amir J. Katz, Silvaco Israel Ltd.
                19 Maskit St., Herzelia, Israel 46733



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