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- Newsgroups: comp.sys.hp
- Path: sparky!uunet!mcsun!sun4nl!alchemy!prisma!fred
- From: fred@cv.ruu.nl (Fred Appelman)
- Subject: Re: backup of NFS partitions: acces denied
- Sender: usenet@cv.ruu.nl (Usenet Network)
- Message-ID: <1992Aug17.070544.24728@cv.ruu.nl>
- Date: Mon, 17 Aug 1992 07:05:44 GMT
- References: <kirchhof.3.713982347@ph1.physik.uni-konstanz.de>
- Nntp-Posting-Host: triton.cv.ruu.nl
- Organization: University of Utrecht, 3D Computer Vision Research Group
- Lines: 143
-
- In <kirchhof.3.713982347@ph1.physik.uni-konstanz.de> kirchhof@ph1.physik.uni-konstanz.de (Thomas Kirchhoff) writes:
-
- >I want to do backups using GNU-tar on a Hp720/HPUX8.05 of NFS
- >mounted partitions. This doesn't work. GNU-tar is saying 'bad filenumber'
- >whenit is told to read read-protected files. I created on both HP's a userid
- >'backup' with uid=0 and primary groupid=3. So this should mean that i can
- >read any file on the NFS-mounted partition, shouldn't it ?
- >The rest of the user and group id's are not the same on both machines.
- >So how am I supposed to do backups via NFS ?
- >
- >thomas.
-
- The userid '0' is automatically mapped to userID NOBODY which has standard
- the value of -2. There are two methods to fix this. You should first ask
- yourselve if you really want to backup over NFS. If you care about
- performance you shouldn't.
-
- Solution 1 (using NFS):
- You have to change the userid of the user 'nobody' from -2 to 0.
- The script below will do this for you. There are some security
- riscs (so I have been told) when you map the user nobody
- from -2 to 0, but I don't know which.
- #! /bin/sh
- #---------------------------------------------------------------------------
- # PATCHKERNEL ??-???-?? Fred Appelman <fred@cv.ruu.nl>
- # rootnfs-1.0 18-Jan-90 Edwin Kremer <edwin@cs.ruu.nl>
- #
- # rootnfs - enable/disable root permission over NFS by
- # setting the kernel variable "_nobody" to
- # 0 or -2 respectively.
- #
- #---------------------------------------------------------------------------
- PATH='/bin:/usr/bin:/etc:/usr/etc' ; export PATH
- PROG=`basename $0`
- #---------------------------------------------------------------------------
- UNIX='/hp-ux' # specify where your UNIX kernel is
- ADB_OPT='-w' # open kernel for writing
- ADB_CMD='W' # write a four-byte value in decimal
- #---------------------------------------------------------------------------
-
- DoMemory()
- {
- echo "nobody/${ADB_CMD}${NOBODY}" |
- adb ${ADB_OPT} ${UNIX} /dev/kmem |
- Display 'MEMORY'
- }
-
- DoDisk()
- {
- echo "nobody?${ADB_CMD}${NOBODY}" |
- adb ${ADB_OPT} ${UNIX} - |
- Display 'DISK'
- }
-
- Display()
- {
- while read line
- do
- echo "$1-> $line"
- done
- }
- Usage()
- {
- echo "Usage: ${PROG} deny|allow|inspect memory|disk|both"
- exit 1
- }
-
- if [ $# -ne 2 ]
- then
- Usage
- fi
-
- case $1 in
- deny)
- NOBODY='-2'
- ;;
- allow)
- NOBODY='0'
- ;;
- inspect)
- NOBODY='' # no need to assign a value
- ADB_OPT='' # no need to open kernel for writing
- ADB_CMD='D' # print a four-byte value in decimal
- ;;
- *)
- Usage
- ;;
- esac
-
- case $2 in
- memory)
- DoMemory
- ;;
- disk)
- DoDisk
- ;;
- both)
- DoMemory
- DoDisk
- ;;
- *)
- Usage
- ;;
- esac
-
- exit 0
-
- Solution 2 (not using NFS):
- Run a remote backup on the NFS exporting host. Start this from
- the host that has the tapeunit. The following script is what
- I use myself. It runs on a host called 'odin', and backups
- disks from three other hosts. You have to setup .rhosts file
- to use this. This script is ofcourse just an example and
- needs editing.
-
- #!/bin/sh
- #
- # datbackup - start backup on prisma, triton and wodan from
- # odin.
-
- HOST=`hostname`
- if [ $HOST != odin ]
- then
- echo Must be run on odin
- exit 1;
- fi
-
- echo `date` Start triton
- remsh triton gnutar cblfz 100 odin:/dev/rmt/0mn /Userspace1
- echo `date` Start wodan
- remsh wodan gnutar cblfz 100 odin:/dev/rmt/0mn /Userspace1
- echo `date` Start prisma
- remsh prisma gnutar cblfz 100 odin:/dev/rmt/0m /Userspace1
- echo `date` Done
-
-
-
- --
- Fred J.R. Appelman, 3D Computer Vision, Utrecht University
- AZU, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
- Telephone: +31-30-506710 Fax: +31-30-513399
- e-mail: fred@cv.ruu.nl or appelman@cs.unc.edu
-
-