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Date: 31 Mar 89 14:45:00 WET
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V7#036
To: "baynes" <baynes@drum>
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Date: Fri, 31 Mar 89 02:45:37 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V7#036
Message-ID: <8903310245.aa08937@SEM.BRL.MIL>
UNIX-WIZARDS Digest Fri, 31 Mar 1989 V7#036
Today's Topics:
Re: friendly messages
Re: /etc/rmt on suns -- does it work? Having trouble, TFM doesn't help
Wanted: POSIX and ANSI C, details and libraries
Re^2: Using sigvec & sigcontext
Re: help needed on a unix system-call question
Re: Wanted: POSIX and ANSI C, details and libraries
Re: micro-code upgrade (and VMS vs. Unix stats)
Re: namei broken
Re: Implications of large memory systems
ranlib: out of memory
Re: Reading raw input from /dev/tty using shell
RCS
Can I tell if my console output is redirected (TIOCCONS)?
processor problems...or just ugliness?
Re: RCS
Re: namei broken
Problems using ACC ACP5250 under 4.3-tahoe
Re: Indent posting
Re: Re^2: Using sigvec & sigcontext
find: bad status-- /u/tu
Re: friendly messages
Re: Problems using ACC ACP5250 under 4.3-tahoe
Re: modems dmf-32s
Re: namei broken
386s and implied OS support
GALACTIC HACKER PARTY
Re: Wanted: POSIX and ANSI C, details and libraries
Re: RCS
Re: micro-code upgrade (and VMS vs. Unix stats)
Re: namei broken
Re: find: bad status-- /u/tu
Re: micro-code upgrade (and VMS vs. Unix stats)
Re: Indent posting
Re: ranlib: out of memory
Re: friendly messages
Booting PWB Unix1.0 to single user
Re: Re^2: Using sigvec & sigcontext
Re: friendly messages
Locking errors
uucp killing
Re: micro-code upgrade (and VMS vs. Unix stats)
mk doesn't work the way I expect
Re: friendly messages
-----------------------------------------------------------------
From: Jim Prescott <jgp@moscom.uucp>
Subject: Re: friendly messages
Date: 29 Mar 89 06:23:02 GMT
To: unix-wizards@sem.brl.mil
In article <3314@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>Perhaps we (the usenet community) should spec a better interface:
A nice quick 90% solution is a printf-like function that writes to stderr,
prepends the program name to the message, and can append the system error
message. Something like:
if (open(fname, O_RDRW, 0) == -1)
errmsg("Cannot open \"%s\" for read/write -- ", fname);
would output:
prog: Cannot open "somefile" for read/write -- Read-only file system
This makes it fairly painless for the programmer to come up with an
informative message without worrying about the little details. Trying
to use perror to get a nice message is too much work, which is probably
why it isn't used as often as it should be.
The problems in implementing this are:
- finding the program name; most likely needs to be stashed away
while in main(). (It would have been nice if the ANSI-C
folks had invented some globals to hold copies of main's
arguments. (I know it isn't their job to invent :-).)
- deciding where to put the system error. The code below tacks it
on the end of the message iff it doesn't end in a newline.
Not a great solution but certainly much simpler than doing
a new % escape.
An enhancement would be introduce error levels (we use FATAL, ERROR, INFO
and DEBUG) and provide some way to specify which you want to see (we default
to FATAL & ERROR).
I've even enclosed a function to implement it below (about 99% of which is
from an article on varargs by Chris Torek). I'm not sure how portable
vsprintf is, its on our sun but wasn't in V7 so it probably isn't universal.
If anyone can tell me where to get a pd vsprintf I'd be grateful.
While we're on the subject, Guy mentioned TECO error messages but not how
nifty they actually are. You can tell it to print just the 3 letter code
(eg. ?FNF), to print the 1 line error (eg. ?FNF File not found.) or to print
the 1 line message followed by a couple of likely paragraphs out of the manual
(this is called "war and peace" mode). Its flexible even if not overly
useful (I can't imagine using anything other than 1 line messages. Maybe
the 3 letter only would be good on 110 baud ttys).
========= varargs version
#include <varargs.h>
int
errmsg(va_alist)
va_dcl /* N.B.: no semicolon */
{
int ret;
char *fmt;
va_list ap;
char buf[1024]; /* shouldn't be fixed size */
va_start(ap);
fmt = va_arg(ap, char *);
ret = vsprintf(buf, fmt, ap);
va_end(ap);
fprintf(stderr, "%s: %s", Progname, buf);
if (*(buf + strlen(buf) - 1) != '\n')
perror("");
return ret;
}
#endif
========= stdarg version
#include <stdarg.h>
int
errmsg(char *fmt, ...) /* the `...'s are part of the syntax */
{
int ret;
va_list ap;
char buf[1024]; /* shouldn't be fixed size */
va_start(ap, fmt);
ret = vsprintf(buf, fmt, ap);
va_end(ap);
fprintf(stderr, "%s: %s", Progname, buf);
if (*(buf + strlen(buf) - 1) != '\n')
perror("");
return ret;
}
--
Jim Prescott moscom!jgp@cs.rochester.edu
{rutgers,ames,harvard}!rochester!moscom!jgp
-----------------------------
From: "David C. Cornutt" <dcornutt@uahcs1.uucp>
Subject: Re: /etc/rmt on suns -- does it work? Having trouble, TFM doesn't help
Date: 29 Mar 89 03:18:04 GMT
To: unix-wizards@sem.brl.mil
In article <3274@ttrdc.UUCP>, levy@ttrdc.UUCP (Daniel R. Levy) writes:
> I have made the apparent mistake of believing the SUN manpage rmt(8C) for
> /etc/rmt, the remote magtape daemon. According to the documentation, as I
> read it, I should be able to start /etc/rmt and feed it commands and data, and
> expect acknowledgments and data back from it. Well, that doesn't seem to work
> very well (read: at ALL). I tried it locally (that shouldn't matter, should
> it?) and here's what happens with a tape, write protect turned off (i.e.
> writeable), in drive /dev/rst0, on a SUN4 under SunOS 4.0:
>
> O /dev/rst0 438 [me -- note that 438 decimal is 0666 octal]
^^^^^^^^^ ^^^
> Daniel R. Levy UNIX(R) mail: att!ttbcad!levy
I went through this same exercise about a year ago. If I remember right
(which I frequently don't), you have to put each of the arguments to
every command on a line by itself; i.e., separate the command args
with newlines instead of spaces.
Sorry about not having a signature or return path. I just got back on
the net after a long absence, and I haven't learned the local topology yet.
David Cornutt
uahcs1
-----------------------------
From: Lee McLoughlin <lmjm@doc.imperial.ac.uk>
Subject: Wanted: POSIX and ANSI C, details and libraries
Date: 28 Mar 89 17:30:00 GMT
Sender: lmjm@doc.ic.ac.uk
To: unix-wizards@sem.brl.mil
I'm working on large program that I want to be as portable as
possible. Although it is mainly aimed at Unix boxes I thought I'd
throw caution to the wind and write it using the emerging standards:
POSIX and ANSI C.
The first problem is how do I get ahold of the POSIX spec' in the UK?
Although I've heard a lot of discussion about POSIX and seen some
libraries that a POSIX compatiable (Doug Gwyn's directory scanning
code for example) I don't recall seeing the name of a book, or whatever,
detailing POSIX.
ANSI C is easier to get ahold of details. I just bought the 2nd edition
of K&R. It seems to be a good general guide, but stddef.h, errno.h and
locale.h don't seem to be documented anywhere.
I'd really like pointers to official publications detailing POSIX and ANSI C.
If anyone knows how to get them in the UK I'd be very grateful.
While I'm asking I'd like public or freely available implementation of
POSIX or ANSI C libraries so that I can port to a wider range of systems.
So far I've only Doug Gwyn's directory stuff and a couple of
programs for converting ANSI C to K&R C (ansi2kr an agcp). Any other
contributions would be greatly appreciated.
thanx in advance
Lee
--
Lee McLoughlin 01 589 5111 X 5028
Department of Computing,Imperial College,180 Queens Gate,London SW7 2BZ, UK
Janet: lmjm@uk.ac.ic.doc Uucp: lmjm@icdoc.UUCP, ukc!icdoc!lmjm
DARPA: lmjm@doc.ic.ac.uk (or lmjm%uk.ac.ic.doc@nss.cs.ucl.ac.uk)
-----------------------------
From: Rene' Seindal <seindal@skinfaxe.diku.dk>
Subject: Re^2: Using sigvec & sigcontext
Date: 28 Mar 89 01:30:32 GMT
Sender: news@freja.diku.dk
To: unix-wizards@sem.brl.mil
chris@mimsy.UUCP (Chris Torek) writes:
> In article <4549@freja.diku.dk> seindal@skinfaxe.diku.dk (Rene' Seindal) writes:
> >On 4.3BSD on Vaxen, the struct sigcontext has the same contents as a
> >``jmp_buf'' (??),
> Not so:
> % egrep jmp_buf /usr/include/setjmp.h
> typedef int jmp_buf[10];
> % egrep sc\|\{\|\} /sys/h/signal.h
> struct sigvec {
> };
> struct sigstack {
> };
> struct sigcontext {
> int sc_onstack; /* sigstack state to restore */
> int sc_mask; /* signal mask to restore */
> int sc_sp; /* sp to restore */
> int sc_fp; /* fp to restore */
> int sc_ap; /* ap to restore */
> int sc_pc; /* pc to restore */
> int sc_ps; /* psl to restore */
> };
> As you can see, sigcontext is not an array of 10 int's.
I hate to argue with you. You are right too often :-)
I said same contents, not same type. A close look at setjmp will reveal that
is only uses the first seven longwords of the jmp_buf, for exactly the values
shown above. A comment even says "# construct sigcontext"! jmp_buf is
probably only declared as an array, so people don't have to take the address
themselves. (I am looking in MORE/bsd sources from Mt. Xinu, marked
"@(#)setjmp.s 5.5 (Berkeley) 3/9/86").
> >Even more amusing, the is an undocumented system call (no. 139) in at least
> >4.3 (and 4.2) from Berkeley, Ultrix 2.0, and SunOS 3.X (and 4.0, according to
> >adb. I haven't tried), which is used by longjmp(3) to restore the saved
> >context. It takes a jmp_buf/struct sigcontext as the sole argument. It is a
> >kind of simplified sigreturn(2). Don't look in sysent for it, since it will
> >probably not be there.
> 139 is (was) the `sigcleanup' syscall, used in 4.2BSD to exit from
> signal handlers, and indeed undocumented. It did not take *any*
> arguments; rather, it found a sigcontext structure via the user stack
> pointer pushed by the `chmk' trap, an awful and bloody thing to do,
> which is of course why it was fixed in 4.3BSD....
You are right about the argument passing. It does, however, look the same
from user code. Code like
pushl <addr of sigcontext or a jmp_buf>
chmk $139
will do a longjmp (without restoring register contents, as 4.[23] longjmp does).
Syscall 139 still exists in the 4.3 I use (MORE/bsd), even though it isn't
listed in sysent. Look in the top of syscall(). That is an awful and bloody
thing to do too. Was it left in only because of longjmp(), which is able to
use sigreturn() instead (more awful and bloody code), or because other
programs depended on it (even more awful and bloody)?
> I have no idea how SunOS actually handles osigcleanup().
I haven't got sources to SunOS 4.0, but it look like it uses the 4.2 scheme.
It has sigcleanup listed as syscall 139 in sysent, taking no arguments. The
code for sigcleanup looks similar, fetching a sigcontext pointer from the user
stack, followed by a copyin of the necessary parts of the sigcontext, and
assignment to the saved registers in the user structure. SunOS hasn't got
sigreturn either, so those parts of the kernel might be from 4.2.
Rene' Seindal (seindal@diku.dk).
-----------------------------
From: der Mouse <mouse@mcgill-vision.uucp>
Subject: Re: help needed on a unix system-call question
Date: 29 Mar 89 11:57:12 GMT
Keywords: signal, system-call, read, unix v
Posted: Wed Mar 29 06:57:12 1989
To: unix-wizards@sem.brl.mil
In article <7553@june.cs.washington.edu>, ka@june.cs.washington.edu (Kenneth Almquist) writes:
> guy@auspex.UUCP (Guy Harris) writes:
>> Assuming by "is it possible to lose the partially read data" you
>> mean "if the 'read' blocks, and then transfers some data and blocks
>> waiting for more data, and *then* gets interrupted by a signal, is
>> the data it transferred more-or-less lost", the answer is "yes, and
>> [...]" [...].
> Reads on cooked tty devices block until an entire line is available
> and then copy in the entire line at once.
The original posting seems to have expired here. There is one common
case which *looks* like "partially read" data being "lost", even though
this is not really true: when the signal coming in is due to a special
character (interrupt or quit, for example) being typed on the tty
that's being read from. In this case, the input buffer is generally
flushed, losing any partial line that's been typed. Until you realize
that the partial line is being buffered in the kernel and not
transferred to the user's buffer until you push return (and therefore
isn't partially read at all), this looks a lot like "losing partially
read data".
The original question probably belonged in comp.unix.questions, but we
all know nobody pays any attention to the distinction any longer :-(.
der Mouse
old: mcgill-vision!mouse
new: mouse@larry.mcrcim.mcgill.edu
-----------------------------
From: Joseph Boykin <boykin@calliope.encore.com>
Subject: Re: Wanted: POSIX and ANSI C, details and libraries
Date: 29 Mar 89 14:54:18 GMT
Sender: news@encore.com
Followup-To: comp.std.c
To: unix-wizards@sem.brl.mil
In article <746@gould.doc.ic.ac.uk> lmjm@doc.ic.ac.uk (Lee McLoughlin) writes:
>The first problem is how do I get ahold of the POSIX spec' in the UK?
Firstly, POSIX is actually the name for what will become a set of standards.
The only one currently approved is 1003.1, the system interface definition
(i.e. system calls). P1003.2 recently went through its first ballot.
I haven't heard what the results were, but generally it takes about 6-9 months
before all the balloting objections are taken care of and a final ballot
is taken.
So, while "POSIX" may not be more than one standard today, there will
be more than one by the end of the year. There are numerous others in
development as well.
Information on obtaining a coy of the 1003.1 standard is below. If you
are interested in becoming active in the POSIX effort, which can mean
anything from just obtaining a copy of the draft documents to actively
participating in meetings, you should contact:
Jim Isaak
Chair, Technical Committee on Operating Systems
Subcommittee on Operating System Standards (TCOS-SS for short!)
DEC, MS ZK03-3/Y25
110 Spit Brook Road
Nashua, NH 03062
603-881-0480
You can obtain a copy of the 1003.1 document from either the IEEE Service
Center, or from IEEE-CS Publications. The catalog for the IEEE was the
top-most on my desk, so here's the information:
Standard Number: 1003.1-1988
Code: SH12211
Cost: $32.00 ($16 for IEEE Members)
Provide Name, Address and IEEE Membership number and send your
check or credit card number to:
IEEE Service Center
445 Hoes Lane
PO Box 1331
Piscataway, NJ 08855
in Canada:
IEEE Canada
7061 Yonge Street
Thornhill, Ontario L3T 2A6
Hope this helps.
----
Joe Boykin
Encore Computer Corp
Vice-Chair, IEEE Computer Societies'
Technical Activities Board
UUCP: encore!boykin
ARPA: boykin@encore.com
-----------------------------
From: Roy Smith <roy@phri.uucp>
Subject: Re: micro-code upgrade (and VMS vs. Unix stats)
Date: 29 Mar 89 17:56:02 GMT
To: unix-wizards@sem.brl.mil
dodgson@cs.wmich.edu (Harry Dodgson) writes:
> The DEC rep will be in this Tuesday to upgrade the microcode to
> level 103. He doesn't know anything about Unix.
Some number of years ago, when our 750 was fairly new, DEC came out
with a "rev 7" upgrade, which was some minor change in the memory controller
having to do with catching cache parity errors, or something like that (I
don't remember exactly, but the details are not that important). DEC
insisted on installing it on our 750 and I foolishly let them.
The result was weeks (or was it months?) of agony. It never worked
right and DEC insisted on putting the blame on the fact that we were running
Unix. Eventually, after GOK how many board swaps, they got us a board that
worked, claiming that they were special-testing boards to find ones that ran
under Unix. When I say I "foolishly" let them install it, what I mean is
that until they did the upgrade, we didn't have any problems; we never had
the symptoms that the upgrade was supposed to cure and after the upgrade we
had *lots* of problems.
My advice is to ask DEC just *why* they want to install the new
microcode, and don't let them unless they have a damn good reason. If your
machine works as it is, what do you have to gain by changing something?
heins@atanasoff.cs.iastate.edu (Leeland Heins) writes:
> ** opinion on :-) ** Does any DEC rep ever say anything but "buy VMS"? :-)
I saw an interesting statistic in (of all places) MacWEEK (21 March
1989, page 60). They did a (somewhat silly) survey of Macs connected to
bigger machines at 269 "very large Macintosh sites". They found that of
Vaxen with "connected" Macs, 54% run only Ultrix (which I take to mean Unix
of various flavors), 37% run a mix of Ultrix and VMS, and only 1% run
strictly VMS. They didn't mention if these were academic or commercial
sites. I hope this doesn't start another VMS vs. Unix war.
--
Roy Smith, System Administrator
Public Health Research Institute
{allegra,philabs,cmcl2,rutgers,hombre}!phri!roy -or- roy@phri.nyu.edu
"The connector is the network"
-----------------------------
From: Barry Shein <bzs@bu-cs.bu.edu>
Subject: Re: namei broken
Date: 29 Mar 89 19:04:59 GMT
To: unix-wizards@sem.brl.mil
> namei() doesn't work!
>
> It's BROKEN!!
What I'm trying to understand is, if it's true, how the guy posted the
message or how any of us are reading or replying to it.
--
-Barry Shein, Software Tool & Die
There's nothing more terrifying to hardware vendors than
satisfied customers.
-----------------------------
From: Unix Consultation Mailbox <consult@osiris.uucp>
Subject: Re: Implications of large memory systems
Date: 29 Mar 89 17:57:34 GMT
To: unix-wizards@sem.brl.mil
In article <13433@steinmetz.ge.com> davidsen@crdos1.UUCP (bill davidsen) writes:
> If the machine is a
>workstation rather than being used for timesharing (many schools try to
>put 32 users on an 8MB Sun), the total memory in use is probably 4-12MB.
We have a pilot system running on a number of single-user diskless Sun 3/50s
and I'll tell you exactly how much memory is in use on each of those
workstations: the entire 4Mb. We had to double the size of all the server
swap partitions just to keep the systems running. And even after taking the
-g's and -gx's out of all the makefiles, *and* stripping all the executables,
it's still Page City.
>Do most users need that in a workstation? I don't, as long as I have
>access to a large machine for those rare problems which can use that
>much memory.
I never needed more than the 4Mb in a 3/50 myself. Of course I was still
doing most of my work on the Pyramids, which helps a lot. (They've all
got >= 16M main memory and hundreds of Mb swap. Zippy!)
phil
-----------------------------
From: David Brown <david@pyr.gatech.edu>
Subject: ranlib: out of memory
Date: 29 Mar 89 18:45:15 GMT
To: unix-wizards@sem.brl.mil
Hiya. It seems that my ranlib is broken. I'm using a Sun 3/60
running SunOS4.0. I've got a directory of .o files that I want
in an archive...so I:
ar crv libjunk.a file1.o file2.o file3.o ... fileN.o
a - file1.o
a - file2.o
a - file3.o
...
a - fileN.o
ranlib libjunk.a
ranlib: ran out of memory
All together, these files don't add up to 200K. Is ranlib on SunOS4.0
broken? I looked over the 'fixes' on the 4.0.1 tape, but there's nothing
on ranlib. And yes, I've tried my WONDERFUL Sun software support ...
I've been waiting for a return call for 6 days now.
I don't have source to pick through, unfortunately. Anyone out there in
netland know of a way around this? Any and all help greatly appreciated!
David Brown
david@pyr.gatech.edu
(912) 927-5342
ps: If anyone at Sun is the least bit interested, the service order
number is 284573.
-----------------------------
From: Jimmy Aitken <jimmy@pyrps5>
Subject: Re: Reading raw input from /dev/tty using shell
Date: 29 Mar 89 19:17:17 GMT
Sender: daemon@pyramid.pyramid.com
To: unix-wizards@sem.brl.mil
In article <52@crdgw1.crd.ge.com> barnett@crdgw1.crd.ge.com (Bruce Barnett) writes:
>Does anyone know a clever method of reading raw data from /dev/tty
>using a shell script and standard Unix tools?
This is the method that I shell script that I use to chnage attributes
of a sun window. The main program has lots of options and needs to
know the current position of the window read via escape sequences.
Note that you musn't type anything whilst it's trying to read the
input as it would get messed up with the stuff that the sun window is
"typing". This runs fine under sunOS 3.5
The code fragment goes something like:
stty raw > /dev/tty
echo -n "escape sequencs that causes the string to be returned" > /dev/tty
ch=`dd </dev/tty count=1 2>/dev/null`
stty cooked > /dev/tty
This can be used e.g:
echo -n "${esc}[18t"
to get the size of the window
>Call me a purist, but I was wondering if I could replace a 10 line C program
>with a 5 line shell script? :-)
Or even 4 line...
-----------------------------
From: Mike McNally <m5@lynx.uucp>
Subject: RCS
Date: 29 Mar 89 21:01:36 GMT
To: unix-wizards@sem.brl.mil
When a file is checked out (with co) of an RCS directory, it seems to me
that it would be nice if the modification date were set to the date of
the revision. This would keep "make" happy.
Because I've just started using RCS in an attempt to bring some sanity
to our software, I might easily be confused. Perhaps there's a good reason
that the file time should be the time of check-out, and I'm just not really
in the RCS groove. Any explanations are welcome.
--
Mike McNally Lynx Real-Time Systems
uucp: {voder,athsys}!lynx!m5 phone: 408 370 2233
Where equal mind and contest equal, go.
-----------------------------
From: Dave Cohrs <dave@romano.cs.wisc.edu>
Subject: Can I tell if my console output is redirected (TIOCCONS)?
Date: 29 Mar 89 23:22:16 GMT
Sender: news@spool.cs.wisc.edu
Keywords: TIOCCONS, SunOS
To: unix-wizards@sem.brl.mil
I'm running SunOS 4.0.1, and I'd like to find out if my console
output is redirected to a pty, and if so, take some action.
How do I tell if the console output is redirected?
thanks
--
Dave Cohrs
+1 608 262-6617 UW-Madison Computer Sciences Department
dave@cs.wisc.edu ...!{harvard,rutgers,ucbvax}!uwvax!dave
-----------------------------
From: Dick Dunn <rcd@ico.isc.com>
Subject: processor problems...or just ugliness?
Date: 27 Mar 89 20:00:48 GMT
To: unix-wizards@sem.brl.mil
jfh@rpp386.Dallas.TX.US (John F. Haugh II) wrote a flame about the 286.
First item of note is that he directed followups to "junk". I don't get
it; was he afraid that someone might try to post a substantive response?
> The 80286 does have problems.
Meaning what? That it's uglier than last week's roadkill? Perhaps so,
but:
>...I doubt that a fully functional and
> robust operating system for an 80286 can ever be had...
There are existence proofs to the contrary. Even the Microport system,
which has some long-standing bugs, *could* be fixed...people are frustrated
with the bugs in the Microport AT stuff precisely because they know they
can be fixed. There is nothing that I know of in the 286 architecture
which prevents one from constructing, say, a correct implementation of
UNIX in which processes are completely protected from one another as they
should be, and in which the kernel is protected from processes such that
no process could cause a kernel panic.
If anyone has any concrete, substantive reason that a 286 cannot support a
correct, robust operating system, I'd like to know what it is. What I'm
looking for is, for example, a way that a program in user mode can cause an
exception that the kernel can't defend against. Let's even include the
usual support chips for the 286 since (a) it doesn't have any useful
interrupt control on-chip, and (b) the 286, as ugly as it is, is actually
rather pleasant next to the cascaded pair of 8259's normally used with it.
I'm not much swayed by an argument like:
>...The chip is brain dead and a waste of good silicon...
since it's a content-free statement, and:
>...Various modes of failure
> cause the program to be completely aborted, and if that program
> happens to be your operating system, tough luck.
amounts to nothing since the same is true of "various modes of failure" on
most processors. Try things like a bad kernel stack pointer, nonexistent
address for load/store, etc., and see what it does to a 680x0, a VAX, a
PDP-11...
> ...Others of us are disgusted with bogus hardware.
> The 80286 is such an example of a total loser implemented on silicon.
No, it's not a total loser. That's nonsense. It IS an unpleasant
processor in many ways. I won't defend the architecture, but just because
it's ugly doesn't mean it's not usable.
In fact, if you get in to the real details of most processors, you'll find
that there are lots of warts. A very few processors are exceptionally
clean in design, like the PDP-11...but even there if you go looking at the
Unibus map or the memory protection, you'll find things are more ornate
than you might like. Of course, the PDP-11 is probably two orders of
magnitude (?quantitative subjectivity?:-) cleaner than the 286, BUT the
286 is still usable. It works (or at least if it doesn't, nobody has
posted a reason yet).
The 286 has a rather baroque memory protection scheme, but at least it has
one. Contrast with the 680x0, which didn't have either an internal MMU or
any accepted external MMU for years. That made it impossible to produce a
UNIX port "for the processor" since the port depended on box-specific
memory management.
If you have a chance to influence architecture, it's great to complain
about all the things that make an operating system ugly or slow...but if
the hardware already exists, you need to take a different tack: See if
everything you need to do is *possible* (note: NOT easy or clean, just
possible)...then get down to it.
Let me try to keep my views in perspective: I've done OS-level work on the
286, and believe me, I complained about the architecture all along. It was
often painful to do things, but it was possible and the result was usable.
--
Dick Dunn UUCP: {ncar,nbires}!ico!rcd (303)449-2870
...Never offend with style when you can offend with substance.
-----------------------------
From: Chris Torek <chris@mimsy.uucp>
Subject: Re: RCS
Date: 30 Mar 89 00:07:55 GMT
To: unix-wizards@sem.brl.mil
In article <5372@lynx.UUCP> m5@lynx.uucp (Mike McNally) writes:
>When a file is checked out (with co) of an RCS directory, it seems to me
>that it would be nice if the modification date were set to the date of
>the revision. This would keep "make" happy.
Since `co' expands RCS keywords, this would be wrong. For instance:
% co -l foo.c
1.1 locked
% edit foo.c
...
% make
...
% ./test foo
works
% ci foo.c
...
% co foo.c
% make
`foo' is up to date.
% ident foo
$Header: ... chris Locked $
%
Other than the single `extra' recompilation (not always unnecessary,
as above), if you keep a copy co'd all the time, this is no problem.
Alternatively, you can use a variant of `make' that knows about RCS
files.
--
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris
-----------------------------
From: Rahul Dhesi <dhesi@bsu-cs.uucp>
Subject: Re: RCS
Date: 29 Mar 89 23:26:00 GMT
To: unix-wizards@sem.brl.mil
In article <5372@lynx.UUCP> m5@lynx.UUCP (Mike McNally) writes:
[about timestaps of files checked out with RCS]:
>Perhaps there's a good reason
>that the file time should be the time of check-out...
...As opposed to the revision time.
Yes, there is. Suppose you check out all files and compile. Now you
change your mind and check out an earlier revision of one of the source
files and type "make" again.
--
Rahul Dhesi UUCP: <backbones>!{iuvax,pur-ee}!bsu-cs!dhesi
ARPA: dhesi@bsu-cs.bsu.edu
-----------------------------
From: Roy Smith <roy@phri.uucp>
Subject: Re: namei broken
Date: 30 Mar 89 02:16:40 GMT
To: unix-wizards@sem.brl.mil
In article <29045@bu-cs.BU.EDU> bzs@bu-cs.BU.EDU (Barry Shein) writes:
> What I'm trying to understand is, if it's true, how the guy posted the
> [namei() doesn't work!, It's BROKEN!!] message or how any of us are
> reading or replying to it.
Oh come on Barry, there you go showing your narrow-minded view of
the universe again :-). There *are* systems capable of posting news
articles that don't have namei() in them. Maybe he used a VMS system?
--
Roy Smith, System Administrator
Public Health Research Institute
{allegra,philabs,cmcl2,rutgers,hombre}!phri!roy -or- roy@phri.nyu.edu
"The connector is the network"
-----------------------------
From: Patrick Barron <pdb@sei.cmu.edu>
Subject: Problems using ACC ACP5250 under 4.3-tahoe
Date: 29 Mar 89 23:16:31 GMT
To: unix-wizards@sem.brl.mil
Has anyone successfully gotten ACC's ACP5250 driver working under
4.3-tahoe? I'm having a problem in which the kernel panics when
turning the ACP5250 board on (using acpconfig); the proximate cause
of the crashes is that, when the driver is trying to write to Unibus
map registers (or what passes for such on a Q-bus...), the pointer
it's using contains garbage, and it goes off and tries to poke at
non-existent memory. This very same driver works just fine under
Wisconsin 4.3BSD+NFS - did something change in the way I/O mapping
is handled in the kernel?
ACC *is* working on the problem, but I was just curious to know if
anyone had seen it before. The sooner I can get this fixed, the
better....
--Pat.
-----------------------------
From: Ozan Yigit <oz@yunexus.uucp>
Subject: Re: Indent posting
Date: 29 Mar 89 22:33:03 GMT
Keywords: indent
To: unix-wizards@sem.brl.mil
In article <18835@adm.BRL.MIL> gaspar@st-louis-emh2.army.mil (Al Gaspar) writes:
>
>... has done a great job in getting the Berkeley/Sun version
>of indent into the public domain.
I did not do much, except to ask/bug some people, contact its original
author, and those others who worked on it, to clarify its original status,
copyright issues etc.
>I noticed that the -bg, -dj, -ndf, -pb, and -npb options from the older
>public domain version are missing from Oz's version of indent posted
>to unix-sources. What I would like to know is if there is someone
>else still working on indent that plans on incorporating the older
>public domain version into Oz's Berkeley/Sun version?
I do not know if you can call the original version public-domain, but
certainly assumed to be publicly-distributable: there is some work
afoot to find ways to babysit the code, and include patches, further
enhancements etc. in a coordinated manner. Some folks at BSD are planning
to do major revisions, and I am sure just about every option to typeset
C code will be included in due time. (tomorrow ? :-)
oz
--
... and I say to them, Usenet: oz@nexus.yorku.ca
`Where the hell were you ......!uunet!utai!yunexus!oz
when the page was blank?' Bitnet: oz@[yulibra|yuyetti]
Harlan Ellison Phonet: +1 416 736-5257x3976
-----------------------------
From: Chris Torek <chris@mimsy.uucp>
Subject: Re: Re^2: Using sigvec & sigcontext
Date: 30 Mar 89 04:04:29 GMT
To: unix-wizards@sem.brl.mil
>>In article <4549@freja.diku.dk> seindal@skinfaxe.diku.dk (Rene' Seindal)
wrote:
>>>On 4.3BSD on Vaxen, the struct sigcontext has the same contents as a
>>>``jmp_buf'' (??),
>to which I said
>>Not so:
In article <4557@freja.diku.dk> seindal@skinfaxe.diku.dk (Rene' Seindal)
replies:
>I said same contents, not same type.
Ah: I misinterpreted.
>[setjmp] uses [only] the first seven longwords of the jmp_buf....
Indeed it does.
>jmp_buf is probably only declared as an array, so people don't have
>to take the address themselves.
Historically, jmp_buf has always been an array; and according to the
pANS for C, it must be so. In fact the array was once used to hold
r6 through r15 (in the days of 4.1BSD), and its size is a holdover.
But the two are not interchangeable, aside from an accident of
implementation (well, of design, in this case). It is reasonable for
setjmp and longjmp to want to preserve more state than a sigcontext
(register contents, for instance, on 680x0s, where the call frame does
not let you restore registers by unwinding). Sticking with jmp_bufs
for longjmp and sigcontexts for signals is much safer.
>Syscall 139 still exists in the 4.3 I use (MORE/bsd) ...
(and in 4.3tahoe)
>Was it left in only because of longjmp() ... or because other
>programs depended on it ... ?
It was left in for backwards compatibility. 4.3BSD-tahoe will still
run most 4.1BSD binaries. (Exceptions are things using the jobs
library, and things using vread and/or vwrite. There may be others.)
--
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris
-----------------------------
From: Bob Ames <bob@rush.howp.com>
Subject: find: bad status-- /u/tu
Date: 29 Mar 89 06:56:13 GMT
Followups-To: unix-pc.general
To: unix-wizards@sem.brl.mil
Anybody seen this:?
3.51# find /u -print
[...]
/u/tutor
/u/tutor/Filecabinet
[...]
/u/tutor/Filecabinet/Profiles/9600bps:A2
find: bad status-- /u/tutor/Filecabinet/practice/sample6.clf
find: bad status-- /u/tutor/Filecabinet/practice/sample5.clf
[...]
find: bad status-- /u/tutor/Filecabinet/practice/sample1.clf
/u/tutor/Wastebasket
/u/tutor/Clipboard
/u/tutor/.history
find: bad status-- /u/hello
find: bad status-- /u/dummy
find: bad status-- /u/someone
[...]
3.51#
The bad status messages continue for the rest of the /u directory.
The only command which seems to be bothered at all with the /u
directory is find. I can cd, ls, od ., anything. All the files
are there and intact. The only reason this error was discovered
is that the Tape Backup software gave the same errors during the
"Checking the file systems" phase of the "Complete Backup".
I did an od -cx /u and the output looked somewhat reasonable for a
directory. There's plenty of space left on the disk. I tried
rebooting. It seems like permissions, but I'm root.
This all started after we brought the machine back from ATT for a
new power supply |-)
Bob
Bob Ames The National Organization for the Reform of Marijuana Laws, NORML
"Pot is the world's best source of complete protein, alcohol fuel, and paper,
is the best fire de-erosion seed, and is america's largest cash crop," USDA
bob@rush.cts.com or ncr-sd!rush!bob@nosc.mil or rutgers!ucsd!ncr-sd!rush!bob
619-743-2546 "We each pay a fabulous price for our visions of paradise," Rush
-----------------------------
From: Chris Torek <chris@mimsy.uucp>
Subject: Re: friendly messages
Date: 30 Mar 89 04:16:50 GMT
To: unix-wizards@sem.brl.mil
In article <1411@moscom.UUCP> jgp@moscom.UUCP (Jim Prescott) writes:
[much deleted; these are retained in order]
> ret = vsprintf(buf, fmt, ap);
> fprintf(stderr, "%s: %s", Progname, buf);
> perror("");
Beware, beware! His flashing eyes, his floating exception!
Oops, a bit of stream of unconsciousness there.
This can produce the infamous sendmail-style message:
Cannot exec /bin/mail: Not a typewriter
because fprintf() can call isatty() which can set errno to ENOTTY.
To fix this you should either save and restore errno, or change the
code to fish the error message directly out of sys_errmsg[], or
use strerror() (if your C library has it).
--
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris
-----------------------------
From: Chris Torek <chris@mimsy.uucp>
Subject: Re: Problems using ACC ACP5250 under 4.3-tahoe
Date: 30 Mar 89 04:26:27 GMT
To: unix-wizards@sem.brl.mil
In article <3104@ci.sei.cmu.edu> pdb@sei.cmu.edu (Patrick Barron) writes:
>Has anyone successfully gotten ACC's ACP5250 driver working under
>4.3-tahoe? ... the kernel panics when turning the ACP5250 board on ...
>... when the driver is trying to write to Unibus map registers ... the pointer
>it's using contains garbage, and it goes off and tries to poke at
>non-existent memory.
Easy:
Between 4.3BSD and 4.3-tahoe, Mike fixed the Unibus code so that it
understands having map registers at a different location from Unibus
adapter registers (if any), and to catch bugs, set the `adapter'
register address to 0xc0000000. That one got caught.
The map registers are now at uhp->uh_mr, rather than
&uhp->uh_uba->uba_map[0].
This does not affect well-behaved vaxif drivers, as they all go
through vaxif/if_uba.c. (The ACC drivers are not well-behaved.)
--
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163)
Domain: chris@mimsy.umd.edu Path: uunet!mimsy!chris
-----------------------------
From: "David E. Miran" <dem@uwslh.uucp>
Subject: Re: modems dmf-32s
Date: 29 Mar 89 21:12:31 GMT
To: unix-wizards@sem.brl.mil
In <400@lclark.UUCP> dan@lclark writes
>
> What I'm trying to do is to connect some 1200/2400 baud modems to our
> VAX 750 (4.3bsd unix) to use as dial-in ports. (The modems are
> 'Hayes compatible' Practical Peripherals...)
followed by a description of the problems involved in trying to handle
multispeed modems, especially with PC terminal emulators that cannot
send a break.
There is a very satisfactory solution to this possible (if you are willing
to buy better modems).
Get some Multitech MT224EH modems (or better yet MT696EH).
These are multispeed modems which run at 2400 baud (9600 for the MT696EH).
These modems have the very useful feature that their phone line speed
does NOT have to match the speed to the computer. They can answer the phone
at speeds of 300, 1200, 2400, 4800 ( with MNP 5 compression) (also 9600
and 19,200 for the MT696EH) while always talking to the computer at a fixed
speed (like 9600). The modem then uses xon/xoff to do flow control.
We have some of the MT224EH modems and really like them. We are planning to
get some MT696EH modems in the near furture. We can buy them for $323 for
the MT224EH and $395 for the MT696EH. Of course, this is a state contract
price but you should be able to get close to these prices.
These modems are the ideal solution to the speed recognition problem for us.
Hope this helps.
--
David E. Miran ...!{rutgers,ucbvax,harvard}!uwvax!uwslh!dem
Wisconsin State Hygiene Lab or dem%uwslh.uucp@cs.wisc.edu
University of Wisconsin (608) 262-0019
465 Henry Mall
Madison, WI 53706
-----------------------------
From: Barry Shein <bzs@bu-cs.bu.edu>
Subject: Re: namei broken
Date: 30 Mar 89 13:32:29 GMT
To: unix-wizards@sem.brl.mil
> Oh come on Barry, there you go showing your narrow-minded view of
>the universe again :-). There *are* systems capable of posting news
>articles that don't have namei() in them. Maybe he used a VMS system?
>--
>Roy Smith, System Administrator
Tell ya what, we'll shut off all the Unix systems on the USENET and he
can try posting it again...
>"The connector is the network"
Indeed.
--
-Barry Shein, Software Tool & Die
There's nothing more terrifying to hardware vendors than
satisfied customers.
-----------------------------
From: David Collier-Brown <daveb@geaclib.uucp>
Subject: 386s and implied OS support
Date: 30 Mar 89 03:01:54 GMT
To: unix-wizards@sem.brl.mil
From article <18250@gatech.edu>, by ken@gatech.edu (Ken Seefried iii):
> I thought about that, but it is my understanding (which surely could
> be wrong) that multics is based on dynamicly allocated, variable size
> segments of potentially large size. Certainly, the 80286 doesn't fit
> this criteria with its fixed size, 64K segments. Also, doesn't
> Multics use more than 4 rings of protection?
[...]
> The 80386 *IS*, however, Multics-on-a-chip...
>
> ...ken seefried iii
> ken@gatech.edu
Well, its a "superset of Unix on a chip", but it falls a bit short
of a good target machine for Multics.
One of the big wins with Mutlicks was the integration of the file
system managment with the active segment managment, which allows one
to fold about three very large special cases into one (possibly
overcomplex) function. This implies:
a "known segment" table of large and variable size
a large number of segments (ie, not four)
a simple mapping from segments to pages (to cut down
redundant descriptor information)
This is, in my humble opinion, HARD on a 386. Not impossible, but
not a shoe-in by any means.
To paraphrase Henry, they shold have spent more time building
implementation capabilities into the hardware, instead of building
policy in...
--dave (its easier to put multics on something like the GE
machine with 1 accumulator and four address registers
[intel segments!] than on a 386) c-b
--
David Collier-Brown. | yunexus!lethe!dave
Interleaf Canada Inc. |
1550 Enterprise Rd. | He's so smart he's dumb.
Mississauga, Ontario | --Joyce C-B
-----------------------------
From: ROP GONGGRIJP <rop@neabbs.uucp>
Subject: GALACTIC HACKER PARTY
Date: 29 Mar 89 05:19:45 GMT
To: unix-wizards@sem.brl.mil
GALACTIC HACKER PARTY
2nd, 3rd, 4th of August 1989
PARADISO, AMSTERDAM, HOLLAND
During the summer of 1989 the world as we know it will go into overload.
An interstellar particle stream of hackers, phone phreaks, radioactivists
and assorted technological subversives will be fusing their energies into a
media melt-down as the global village plugs into Amsterdam for three
electrifying days of information interchange and electronic capers.
Aided by the advanced communications technology to which they are
accustomed, the hacker forces will discuss strategies, play games,
and generally have a good time. Free access to permanently open
on-line facilities will enable them to keep in touch with home base --
wherever that is.
Those who rightly fear the threat of information tyranny and want to
learn what they can do about it are urgently invited to interface in
Amsterdam in August. There will be much to learn from people who know.
Celebrity guests with something to say will be present in body or
electronic spirit.
The Force must be nurtured. If you are refused transport because your
laptop looks like a bomb, cut off behind enemy lines, or unable to attend
for any other reason, then join us on the networks. Other hacker groups
are requested to organize similar gatherings to coincide with ours. We
can provide low-cost international communications links during the
conference.
For further information, take up contact as soon as possible with:
HACK-TIC PARADISO
P.O. box 22953 Weteringschans 6-8
1100 DL Amsterdam 1017 SG Amsterdam
The Netherlands The Netherlands
tel: +31 20 6001480 tel: +31 20 264521 / +31 20 237348
fax: +31 20 763706 fax: +31 20 222721
uucp : ..!mcvax!neabbs!rop
fido : 2:280/1 Hack Tic
telex: 12969 neabs nl
Please relay this announcement through all channels of communication
that you can access.
SPREAD THE BYTE, SPREAD THE BYTE, SPREAD THE BYTE, SPREAD THE BYTE
-----------------Amsterdam, spring 1989---------------------------
-----------------------------
From: Nick Maclaren <nmm@computer-lab.cambridge.ac.uk>
Subject: Re: Wanted: POSIX and ANSI C, details and libraries
Date: 29 Mar 89 19:31:40 GMT
Sender: news@cl.cam.ac.uk
Posted: Wed Mar 29 20:31:40 1989
To: unix-wizards@sem.brl.mil
The people to contact about both POSIX and ANSI C in this country are
the BSI. There is likely to be another ISO Draft Proposal on ANSI C,
with a corresponding BSI DP, and that is a good opportunity to get a
copy of the current draft. POSIX I am less in touch with. I am not sure
of the best address to contact in the BSI, and it is a somewhat rambling
organisation (several locations in London, Milton Keynes etc.) Try
chasing up via one of the London locations.
WARNING: do NOT rely on the second edition of K&R. They 'jumped the
gun' and predicted the future wrong; I believe that they are working on
a corrected second edition. I would also suggest working from the real
standard, unless K&R second edition is considerably more thorough than
the first edition.
Nick Maclaren
University of Cambridge Computer Laboratory
nmm@uk.ac.cam.cl
-----------------------------
From: Mike McNally <m5@lynx.uucp>
Subject: Re: RCS
Date: 30 Mar 89 15:37:06 GMT
To: unix-wizards@sem.brl.mil
In article <16623@mimsy.UUCP> chris@mimsy.UUCP (Chris Torek) writes:
>Since `co' expands RCS keywords, this would be wrong. For instance:
...
In article <6389@bsu-cs.UUCP> dhesi@bsu-cs.UUCP (Rahul Dhesi) writes:
>Yes, there is. Suppose you check out all files and compile. Now you
>change your mind and check out an earlier revision of one of the source
>files and type "make" again.
OK, I see. I admit that the obvious (and nearly transparent) solution
of keeping all the sources checked out (read only) is correct. In
addition to these two responses, a more clued-in person here tipped
me off to the scene.
On the subject of RCS: I saw, in a message from some archive somewhere,
mention of some sort of registration that should be carried out with the
creator of the RCS system. I can't find any mention of this in the sources
I have (which I think came from the usenet archive).
--
Mike McNally Lynx Real-Time Systems
uucp: {voder,athsys}!lynx!m5 phone: 408 370 2233
Where equal mind and contest equal, go.
-----------------------------
From: Karl Kleinpaste <karl@triceratops.cis.ohio-state.edu>
Subject: Re: RCS
Date: 30 Mar 89 18:27:43 GMT
Sender: news@tut.cis.ohio-state.edu
To: unix-wizards@sem.brl.mil
m5@lynx.uucp (Mike McNally) writes:
On the subject of RCS: I saw, in a message from some archive somewhere,
mention of some sort of registration that should be carried out with the
creator of the RCS system. I can't find any mention of this in the sources
I have (which I think came from the usenet archive).
See the file rcs/src/READ_ME in your RCS distribution tree.
-----------------------------
From: Rick Ace <rta@pixar.uucp>
Subject: Re: micro-code upgrade (and VMS vs. Unix stats)
Date: 30 Mar 89 17:02:08 GMT
To: unix-wizards@sem.brl.mil
In article <3729@phri.UUCP>, roy@phri.UUCP (Roy Smith) writes:
> Some number of years ago, when our 750 was fairly new, DEC came out
> with a "rev 7" upgrade, which was some minor change in the memory controller
> having to do with catching cache parity errors, or something like that (I
> don't remember exactly, but the details are not that important). DEC
> insisted on installing it on our 750 and I foolishly let them.
>
> The result was weeks (or was it months?) of agony. It never worked
> right and DEC insisted on putting the blame on the fact that we were running
> Unix. Eventually, after GOK how many board swaps, they got us a board that
> worked, claiming that they were special-testing boards to find ones that ran
> under Unix. When I say I "foolishly" let them install it, what I mean is
> that until they did the upgrade, we didn't have any problems; we never had
> the symptoms that the upgrade was supposed to cure and after the upgrade we
> had *lots* of problems.
>
> My advice is to ask DEC just *why* they want to install the new
> microcode, and don't let them unless they have a damn good reason. If your
> machine works as it is, what do you have to gain by changing something?
I suspect DEC will answer like this: "Because Field Service will
soon refuse to support Vax-11/750 systems that are not up to Rev 7."
This is true of hardware and software alike. It makes no
economic sense for a vendor to support previous versions of
products when the current versions are supersets of their
predecessors. Now in Roy's case, the Rev 7 upgrade did
not deliver a superset of what it replaced. However, it's
probably true that DEC had no idea that things were going to
get worse when they did the upgrade. (As an example, Field
Service upgraded two 750s at NYIT to Rev 7 a few years ago,
and outside of my having to figure out how to make 4.2bsd
load the microcode, both upgrades went smoothly.)
Roy, the best thing you could have done was to demand that
DEC commit to a date (as early as you bargain for) by which
they will either make Rev 7 work or return you to your
previous revision level. If the local F-S manager won't
buy into that, talk to his/her superior(s) until you get
satisfaction.
Rick Ace
Pixar
3240 Kerner Blvd, San Rafael CA 94901
...!{sun,ucbvax}!pixar!rta
-----------------------------
From: "Brian V. Smith" <envbvs@epb2.lbl.gov>
Subject: Re: namei broken
Date: 30 Mar 89 19:07:40 GMT
Sender: usenet@helios.ee.lbl.gov
To: unix-wizards@sem.brl.mil
I hate to sound stupid when I'm just ignorant, but
what is namei()? Neither our Ultrix nor SunOs systems have
a manual entry for it.
_____________________________________
Brian V. Smith (bvsmith@lbl.gov)
Lawrence Berkeley Laboratory
We don't need no stinking signatures!
-----------------------------
From: Mike Wescott <wescott@ncrcae.columbia.ncr.com>
Subject: Re: find: bad status-- /u/tu
Date: 30 Mar 89 16:30:34 GMT
To: unix-wizards@sem.brl.mil
In article <948@rush.howp.com> bob@rush.howp.com (Bob Ames) writes:
> /u/tutor/Filecabinet/Profiles/9600bps:A2
> find: bad status-- /u/tutor/Filecabinet/practice/sample6.clf
> /u/tutor/.history
> find: bad status-- /u/hello
> The bad status messages continue for the rest of the /u directory.
One of the directories that find goes through right before the "bad status"
messages start probably has a ".." that is not the parent that find used
to get to the directory.
Try this in /u and some other directories:
ls -id . */..
Each time you should get the same inode number for each directory. Any
mismatch causes find to take the wrong path in trying to get back to where
it started from.
You can use /etc/link and /etc/unlink to fix.
-----------------------------
From: Rahul Dhesi <dhesi@bsu-cs.uucp>
Subject: Re: micro-code upgrade (and VMS vs. Unix stats)
Date: 30 Mar 89 20:17:16 GMT
To: unix-wizards@sem.brl.mil
In article <3623@pixar.UUCP> rta@pixar.UUCP (Rick Ace) writes:
>However, it's
>probably true that DEC had no idea that things were going to
>get worse when they did the upgrade.
Doubtful. It's a well-known and unfortunate fact of life that many
changes in DEC hardware and software are done mostly to break
third-party products.
--
Rahul Dhesi UUCP: <backbones>!{iuvax,pur-ee}!bsu-cs!dhesi
ARPA: dhesi@bsu-cs.bsu.edu
-----------------------------
From: Rich Salz <rsalz@bbn.com>
Subject: Re: Indent posting
Date: 30 Mar 89 19:30:50 GMT
To: unix-wizards@sem.brl.mil
In article <18835@adm.BRL.MIL> gaspar@st-louis-emh2.army.mil (Al Gaspar) writes:
=... has done a great job in getting the Berkeley/Sun version
=of indent into the public domain.
In <1421@yunexus.UUCP> oz@yunexus.UUCP (Ozan Yigit) writes:
=I did not do much, except to ask/bug some people, contact its original
=author, and those others who worked on it, to clarify its original status,
=copyright issues etc.
You did a lot. This kind of nitty-gritty detail work can be a real
drag, and the work who did is really appreciated!
= there is some work
=afoot to find ways to babysit the code
Keith Bostic of UCB <bostic@okeeffe.berkeley.edu> has someone working
on it, and I've had anyone who wrote patches, or who volunteered to work
on the code, to contact him. When the new version is ready, it will
appear in comp.sources.unix
/r$
--
Please send comp.sources.unix-related mail to rsalz@uunet.uu.net.
-----------------------------
From: "John F. Haugh II" <jfh@rpp386.dallas.tx.us>
Subject: Re: ranlib: out of memory
Date: 30 Mar 89 15:25:01 GMT
To: unix-wizards@sem.brl.mil
In article <7758@pyr.gatech.EDU> david@pyr.gatech.edu (David Brown) writes:
>I don't have source to pick through, unfortunately. Anyone out there in
>netland know of a way around this? Any and all help greatly appreciated!
Try tsort and lorder.
--
John F. Haugh II +-Quote of the Week:-------------------
VoiceNet: (214) 250-3311 Data: -6272 | "Do not drink and bake"
InterNet: jfh@rpp386.Dallas.TX.US | -- Arnold Swartzenegger
UucpNet : <backbone>!killer!rpp386!jfh +--------------------------------------
-----------------------------
From: Peter da Silva <peter@ficc.uu.net>
Subject: Re: friendly messages
Date: 30 Mar 89 15:41:16 GMT
To: unix-wizards@sem.brl.mil
Neither of these solutions is correct:
In article <1411@moscom.UUCP>, jgp@moscom.UUCP (Jim Prescott) writes:
> fprintf(stderr, "%s: %s", Progname, buf);
> if (*(buf + strlen(buf) - 1) != '\n')
> perror("");
If this is the first time I/O is done, on at least some machines stdio
will call isatty(0) to determine if stdout should be unbuffered. It will
not save and restore errno. Your program may give such useful advice
as:
foobar: can't open file barfoo -- Not a typewriter.
or:
foobar: can't open file barfoo -- Inappropriate ioctl for device.
--
Peter da Silva, Xenix Support, Ferranti International Controls Corporation.
Business: uunet.uu.net!ficc!peter, peter@ficc.uu.net, +1 713 274 5180.
Personal: ...!texbell!sugar!peter, peter@sugar.hackercorp.com.
-----------------------------
From: Quentin Fennessy <quentin@umb.umb.edu>
Subject: Booting PWB Unix1.0 to single user
Date: 30 Mar 89 20:18:19 GMT
To: unix-wizards@sem.brl.mil
I previously asked:
>I just found an old PDP11/44 in the back of our computer room. Until today
>I thought it ran only RSX, but I found an old Unix manual with it. I have been
>told that Unix is still on the disk.
>I would love to boot this machine, especially with the chance of finding
>source, (old, but source nonetheless) on it.
>The manual calls it PWB/UNIX Edition 1.0, with dates all in 1977.
Well, it has booted, but not to single user. Unfortunately all passwords
are history, and all I get is login:
When the machine boots, it says something like:
rc 1.5 booting pwbe0604 to multi-user
and then runs fsck on the system disk. It finds one file system corrupt,
tells me to find the sysadmin, and tells me to press HALT.
At this point everything I type is merely echoed. If I type <DEL>,
I get a login prompt. I cannot get this to singleuser.
If anyone can help me, I would really appreciate it.
Thanks a lot for your help. Email is best, and if there is interest I will
document my progress for the net.
Quentin Fennessy
home 617-327-0660
work 617-499-4200
harvard!hub.umb.edu!quentin
harvard!hub!umb!quentin
-----------------------------
From: Guy Harris <guy@auspex.uucp>
Subject: Re: Re^2: Using sigvec & sigcontext
Date: 30 Mar 89 23:11:07 GMT
To: unix-wizards@sem.brl.mil
>I said same contents, not same type. A close look at setjmp will reveal that
>is only uses the first seven longwords of the jmp_buf, for exactly the values
>shown above. A comment even says "# construct sigcontext"! jmp_buf is
>probably only declared as an array, so people don't have to take the address
>themselves.
Well, it's declared as an array because it antedates "struct
sigcontext", because it was done that way in good old V7, and because
you're supposed to use the name of the "jmp_buf" in calls to "setjmp",
which means that, since C generally supports call-by-value, the value
had better be a pointer into the "jmp_buf", which means that (unless
"setjmp" is a macro - which the dpANS for C says it must be - *and*
inserts the "&" for you), "jmp_buf" must be an array (in fact, said
dpANS says it's an array).
>> 139 is (was) the `sigcleanup' syscall, used in 4.2BSD to exit from
>> signal handlers, and indeed undocumented. It did not take *any*
>> arguments; rather, it found a sigcontext structure via the user stack
>> pointer pushed by the `chmk' trap, an awful and bloody thing to do,
>> which is of course why it was fixed in 4.3BSD....
>
>You are right about the argument passing. It does, however, look the same
>from user code. Code like
>
> pushl <addr of sigcontext or a jmp_buf>
> chmk $139
>
>will do a longjmp (without restoring register contents, as 4.[23]
>longjmp does).
Which isn't quite the same as "finding the structure via the user stack
pointer pushed by the 'chmk' trap"; I read that as meaning that no
explicit argument is provided, and that the structure is assumed to be
at a specific location on the stack. Instead, "syscall 139" *does* take
an argument; it just happens to be passed a little differently.
Given that neither it nor "sigreturn" are, in general, usable from
machine-independent code ("sigreturn" doesn't load up all the registers,
which means you need machine-dependent glue around it anyway, if you
want something that amounts to a "machine-independent user-mode context
switch" call), I don't see this as being particularly awful or bloody.
There *was* some problem with the 4.2BSD "syscall 139"; I don't remember
what it was, but as I remember it did *not* exist in the SunOS "syscall
139".
>Syscall 139 still exists in the 4.3 I use (MORE/bsd), even though it isn't
>listed in sysent. Look in the top of syscall(). That is an awful and bloody
>thing to do too. Was it left in only because of longjmp(), which is able to
>use sigreturn() instead (more awful and bloody code), or because other
>programs depended on it (even more awful and bloody)?
"longjmp" in 4.3 *does* use "sigreturn". I presume it was left in so
that 4.2BSD binaries would continue to run.
>I haven't got sources to SunOS 4.0, but it look like it uses the 4.2 scheme.
>It has sigcleanup listed as syscall 139 in sysent, taking no arguments. The
>code for sigcleanup looks similar, fetching a sigcontext pointer from the user
>stack, followed by a copyin of the necessary parts of the sigcontext, and
>assignment to the saved registers in the user structure. SunOS hasn't got
>sigreturn either, so those parts of the kernel might be from 4.2.
SunOS doesn't have "sigreturn" because it didn't need it; as indicated,
"sigreturn" isn't a machine-independent interface to a general "context
switch" function, and since making such a function out of "sigreturn"
would require additional machine-language glue to load up the other
registers anyway, it wasn't deemed worth adding as a "real" system call.
That part of the kernel isn't from 4.2, though, except on those versions
of SunOS 3.0 ported to the VAX - neither VAX nor Tahoe code works as is
on the 68K, the 80386, or the SPARC....
-----------------------------
From: Guy Harris <guy@auspex.uucp>
Subject: Re: friendly messages
Date: 30 Mar 89 23:27:57 GMT
To: unix-wizards@sem.brl.mil
>A nice quick 90% solution is a printf-like function that writes to stderr,
>prepends the program name to the message, and can append the system error
>message. Something like:
> if (open(fname, O_RDRW, 0) == -1)
> errmsg("Cannot open \"%s\" for read/write -- ", fname);
>would output:
> prog: Cannot open "somefile" for read/write -- Read-only file system
CAREful - you may want to call this function for errors that *don't*
cause "errno" to be set. You might want to have some way to indicate
whether it should use "errno" or not - or, perhaps, just use the
(dp)ANSI C routine "strerror", which takes an "errno" as argument and
returns a pointer to the appropriate error message string, and just
stick "%s"es into the message string and calls to "strerror" into the
argument list. (If your implementation doesn't have "strerror", it's
probably a 5-minute job to whip one up, at least under UNIX.)
>This makes it fairly painless for the programmer to come up with an
>informative message without worrying about the little details. Trying
>to use perror to get a nice message is too much work, which is probably
>why it isn't used as often as it should be.
Yes, but unfortunately burying the call to "perror" in "errmsg" has its
own problems. Note also that there are places other than "errno" where
errors are reported (by other packages, such as TLI, ONC RPC, database
libraries, etc.), often with their own families of error codes and messages,
so you may end up having to stick calls to the "return error message"
code in *anyway* in some cases....
-----------------------------
From: "Chris A. Anderson" <caanders@sactoh0.uucp>
Subject: Locking errors
Date: 30 Mar 89 23:03:34 GMT
Keywords: lock tables informix c-isam
To: unix-wizards@sem.brl.mil
I'm having a nasty problem with locking using C-ISAM (v. 1.20)
on a Plexus P-95 (SysV.2 K1.7 k80 m68).
Specifically, we're getting a errno=34 when a program attempts to
open a file. In <sys/errno.h>, this is doubly defined: as ERANGE,
and as EDEADLK. Informix thinks that EDEADLK is the most probable
definition for errno=34 in this case. Lock table overflow seems to
be the most likely reason to get EDEADLK... in <sys/params.h>, NFLOCK
is defined as 100. We've confirmed by testing that lock table over-
flow is what the problem is.
How do we change NFLOCK? To relink the kernel we'd need some source
from Plexus (this may be difficult :-) ). Is there any other way?
If we did redefine NFLOCK, what other side-effects could we run
into? Any help would be appreciated!
Thanks in advance.
Chris
--
Chris Anderson email: ...!pacbell!sactoh0!utgard!chris
QMA, Inc. or: ...!csusac!fenris
--------------------------------------------------------------------
-----------------------------
From: "James C. Benz" <jcbst3@cisunx.uucp>
Subject: uucp killing
Date: 30 Mar 89 20:54:39 GMT
To: unix-wizards@sem.brl.mil
For my peace of mind, is there some way to kill all spooled jobs for a given
machine queued for uucp? Let me put that a little more clearly. Suppose
I have a machine foobar, and I have ten jobs queued for uucp to foobar.
Foobar has just been relegated to the scrap heap, so these jobs will never
get sent, or maybe I just discovered an error in the list of files that I
sent to foobar. Anyway, I want to kill all jobs queued for sending to foobar.
I can sit here and type "uustat -k{idnum}" ten times, which seems like an
enormous waste of time (it is - I do it a lot). What I would like to do is
something like "uustat -kfoobar*", which doesn't work (can't find job foobar*-
not killed). I suppose I could do something like "uustat -sfoobar|shellscript"
but then I have to write a shellscript and keep a copy on each machine I work
on just for this. Does anyone know of a way to structure the uustat call so
I can do this generically? (running ATTsysV on a 3B2) (If this seems trivial,
I guess its just because I'm a little bored today :-} )
--
Jim Benz jcbst3@unix.cis.pittsburgh.edu If a modem
University of Pittsburgh answers,
UCIR (412) 648-5930 hang up!
-----------------------------
From: Roy Smith <roy@phri.uucp>
Subject: Re: micro-code upgrade (and VMS vs. Unix stats)
Date: 31 Mar 89 02:50:37 GMT
To: unix-wizards@sem.brl.mil
In article <3623@pixar.UUCP> rta@pixar.UUCP (Rick Ace) writes:
> It makes no economic sense for a vendor to support previous versions of
> products when the current versions are supersets of their predecessors.
> [...] Roy, the best thing you could have done was to demand that DEC
> commit to a date (as early as you bargain for) by which they will either
> make Rev 7 work or return you to your previous revision level.
Rick is, of course, right. In the end, what happened was
essentially what Rick suggested; I demanded that if they couldn't fix they
they had to put it back to how it was before they started, which eventually
they did (fix it, that is). For the record, once the bugs were ironed out,
it did work, and has worked fine for years since. Those of you who have
followed my rantings over the years know that I'm pretty cynical when it
comes to DEC field service; sometimes I get carried away.
As a case in point, on the AppleTalk network I try to administer, I
don't let anybody plug in a Mac unless they are running the latest version
of the system software (or, in the case of 6.0, the latest version that I
decree to be working properly). I suppose some people get pissed at me
when I demand that they upgrade their system software when what they are
running now works fine for them.
--
Roy Smith, System Administrator
Public Health Research Institute
{allegra,philabs,cmcl2,rutgers,hombre}!phri!roy -or- roy@phri.nyu.edu
"The connector is the network"
-----------------------------
From: Guy Middleton <gamiddleton@watmath.waterloo.edu>
Subject: mk doesn't work the way I expect
Date: 31 Mar 89 02:54:49 GMT
To: unix-wizards@sem.brl.mil
We just got mk, and I tried running this mkfile:
PROGS = host addr hostaddr
all:V: $PROGS
$PROGS:
$CC -o $target $target.c
I expected this to happen:
cc -o host host.c
cc -o addr addr.c
cc -o hostaddr hostaddr.c
Instead, I got this:
cc -o host addr hostaddr host addr hostaddr.c
I got what I expected when the "all:V: $PROGS" line was removed.
Why does it work this way? Am I missing something obvious?
-Guy Middleton, University of Waterloo gamiddleton@watmath.waterloo.edu
-----------------------------
From: Dave Hammond <daveh@marob.masa.com>
Subject: Re: friendly messages
Date: 30 Mar 89 22:54:36 GMT
To: unix-wizards@sem.brl.mil
In article <1411@moscom.UUCP> jgp@moscom.UUCP posts his favorite error
message printer.
I note that for a return value it provides the return from vsprintf.
Since error message printers are typically invoked prior to a return,
or exit, I opt to have my favorite error printer return -1.
While this, perhaps, bastardizes the significance of the function's return
value, it (more often than not) makes for convenient error handling:
...
if (an_error_occurred)
return(errmsg(errcode, "Can't open file %s.", fname));
Obviously this presumes that the calling function normally returns -1 as
an its error condition value. Functions which don't employ a -1 error
return just void the return from the error printer.
--
Dave Hammond
daveh@marob.masa.com
-----------------------------
End of UNIX-WIZARDS Digest
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----Reason for mail failure follows----
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----Transcript of message follows----
Date: 15 Mar 90 07:25:00 MST
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V9#094
To: "math!ckaul" <math!ckaul@cs.sandia.gov>
Return-Path: <incoming-unix-wizards-request@sandia.gov>
Received: from SEM.BRL.MIL by sandia.gov with SMTP ;
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Date: Thu, 15 Mar 90 05:45:04 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V9#094
Message-ID: <9003150545.aa06456@SEM.BRL.MIL>
UNIX-WIZARDS Digest Thu, 15 Mar 1990 V9#094
Today's Topics:
System V kernel panic not syncing
Re: Which is more portable: stty < or stty >
Use of ssignal() in Sys V.
Re: Use of ssignal() in Sys V.
Setting multiple timers from a single process.
Re: Setting multiple timers from a single process.
serious awk bug
Re: serious awk bug
Re: Raw disk I/O
repeatability of select()
Re: repeatability of select() (correction)
Re: ADDING TO TAPE ARCHIVES - AHA1540+2150s
Re: Dr David G Korn to speak at SVNet
Re: Large Unix, SYS5.4 on Unisys
mac postscript in ditroff input?
Re: Setting the access/modify time on a file
-----------------------------------------------------------------
From: neal@mnopltd.uucp
Subject: System V kernel panic not syncing
Date: 13 Mar 90 15:03:53 GMT
Posted: Tue Mar 13 10:03:53 1990
To: unix-wizards@sem.brl.mil
->Anyone know how to get the SCO UNIX System V/386 r3.2 kernel
->to do sync when it panics so fsck is happy when you start up again?
->
->I'm told that BSD can do this, and I have a use for this while
->running this OS on a 'beta' CPU which will cause a panic under
->certain circumstances.
Wait a second... This doesn't make sense. Panics are frequently situations
where the kernel code is not confident to continue processing. Doing a
sync in this situation is like painting over rust. For any degree of system
stability you need to fsck and "take your medecine"...
------------------------------------------------------------------------------
Neal Rhodes MNOP Ltd (404)- 972-5430
President Lilburn (atlanta) GA 30247 Fax: 978-4741
uunet!emory!jdyx!mnopltd!neal Or uunet!gatech!stiatl!mnopltd!neal
------------------------------------------------------------------------------
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: Which is more portable: stty < or stty >
Date: 13 Mar 90 19:18:10 GMT
To: unix-wizards@sem.brl.mil
>Currently, 4.0.3 defaults to using the native stty. According to a
>Sun rep, the next release (4.1) will default to the System V version,
>although the next version (5.0) will not have any "preference" (his
>word, which he could not explain). It actually sounded to me like
>that have simply not yet decided.
It sounds to *me* like your Sun rep is seriously confused. (If he
couldn't explain his use of "preference", why was he using it? Yeesh.)
As of when I left Sun, the intent was to have the BSD environment be the
"default", in the sense that if the environment variable PATH isn't set,
the "default" path will *not* have "/usr/5bin" before "/bin" or
"/usr/bin" (BTW, in SunOS 4.x, there's no point in having "/bin" in your
path at all, if you have "/usr/bin" there - "/bin" is just a symlink to
"/usr/bin").
"5.0" has not necessarily been chosen as the name for Sun's System V
Release 4-based release. If the rep was thinking of that release, the
"stty" in "/usr/bin" or wherever will, as one would expect, have the
System V behavior. I don't know if System V Release 4 from AT&T will
have a "/usr/ucb/stty" that provides the BSD behavior or not; even if
they don't, Sun might put one into their release.
>Will POSIX provide an answer, or perhaps, provide a stty90 which has a
>real interface?
According to my copy of Draft 9 of 1003.2:
The "stty" utility sets or reports on terminal I/O
characteristics for the device that is its standard input.
I don't think this is the latest draft, but I'd be surprised if they
changed this in a later draft.
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: Which is more portable: stty < or stty >
Date: 13 Mar 90 19:22:38 GMT
To: unix-wizards@sem.brl.mil
>The former is the 7th Ed. UNIX and 4BSD behavior.
>System V assumes you may want to redirect the output somewhere other
>than the terminal being probed.
You can do that with the V7 and BSD one, it's just more painful - you
have to redirect the standard error.
The S5 behavior is a bit more natural, in that its output goes to, well,
the standard output; the only reason I can see for the V7 behavior is
that it makes it possible to set the modes on a tty other than one on
which you're logged in without being super-user, since traditionally
ttys have been publicly writable but not publicly readable.
While in some environments this would be considered a feature ("Hey,
Jane, I screwed up my tty settings; could you fix them for me? I'm on
'/dev/tty73'."), it would be considered a problem in others
("stty erase 's' kill 't' intr 'y' >/dev/tty73").
Given that in 4.3BSD and now S5R4 ttys are *not* publicly writeable, but
writeable only by a special group, to which programs like "write" are
set-GID (so that you can't send things like the "transmit screen to
host" escape sequence to somebody else's terminal), the V7 behavior
doesn't buy you anything any more.
-----------------------------
From: "Frank I. Reiter" <frank@rsoft.bc.ca>
Subject: Re: Which is more portable: stty < or stty >
Date: 14 Mar 90 15:40:19 GMT
To: unix-wizards@sem.brl.mil
In article <3354@muffin.cme.nist.gov> libes@cme.nist.gov (Don Libes) writes:
>According to the man page (SunOS 4.0.3) ...
>The native SunOS stty(1) acts on the device that is the current stdout
>while their System V stty acts on the device that is the current stdin.
Why not both? stty </dev/x >/dev/x
--
_____________________________________________________________________________
Frank I. Reiter UUCP: {uunet,ubc-cs}!van-bc!rsoft!frank
Reiter Software Inc. frank@rsoft.bc.ca, a2@mindlink.UUCP
Surrey, British Columbia BBS: Mind Link @ (604)576-1214, login as Guest
-----------------------------
From: Johan Vromans <jv@mh.nl>
Subject: Re: Which is more portable: stty < or stty >
Date: 14 Mar 90 20:08:58 GMT
Sender: news@mhres.mh.nl
To: unix-wizards@sem.brl.mil
In article <JV.90Mar13162312@squirrel.mh.nl> jv@mh.nl (Johan Vromans) writes:
`[SystemV:]
`
` STTY_FLAGS=`stty -g < /dev/tty`
` sane() { stty ${STTY_FLAGS}; }
`
`You can't do this from your BSD .login .
To which andyb@coat.com (Andy Behrens) replies:
` STTY_OUTPUT=`stty 2>&1 >/dev/tty`
`
`Of course, BSD doesn't support 'stty -g', but that's another issue.
My BSD system (Ultrix) does. But I mentioned a '.login' file for Csh.
Maarten "als iemand 't kan, is hij het wel" Lithmaat replies:
`Indeed. But if BSD's stty(1) would have had `-g', you *could* have done:
`
` set STTY_FLAGS="`(stty -g > /dev/tty) |& cat`"
Now this works.
Johan
--
Johan Vromans jv@mh.nl via internet backbones
Multihouse Automatisering bv uucp: ..!{uunet,hp4nl}!mh.nl!jv
Doesburgweg 7, 2803 PL Gouda, The Netherlands phone/fax: +31 1820 62944/62500
------------------------ "Arms are made for hugging" -------------------------
-----------------------------
From: Ravi Ramachandran <rr@csuna.cs.uh.edu>
Subject: Use of ssignal() in Sys V.
Date: 14 Mar 90 05:28:16 GMT
Sender: nntppost@uhnix1.uh.edu
To: unix-wizards@sem.brl.mil
The man pages for ssignal & gsignal on Sys V are as succint as usual.
I tried looking up a few adv. Unix books, but none of them ever mention
ssignal. The way I have used it is to use ssignal to initialize the
software signal, and then use gsignal to raise it. But this seems more
like another version of using setjmp() or calling a procedure. Is there
any use for ssignal()? Can I use it between processes (I tried it & it
didn't seem to work)? I know the man pages says that the C compiler uses
it. But unless there is some way a parallel thread can send a signal,
it does not seem too useful.
Thanx for shedding any light (I SAID BUD LITE),
--ravi-
-----------------------------
From: Doug Gwyn <gwyn@smoke.brl.mil>
Subject: Re: Use of ssignal() in Sys V.
Date: 15 Mar 90 00:24:18 GMT
To: unix-wizards@sem.brl.mil
In article <24199@uhnix1.uh.edu> rr@cs.uh.edu writes:
>Is there any use for ssignal()? Can I use it between processes ...?
While one can figure out ways to use ssignal/gsignal, they are not
essential. Certainly they cannot be used for IPC, only within one
process. I suggest never using them.
-----------------------------
From: Ravi Ramachandran <rr@csuna.cs.uh.edu>
Subject: Setting multiple timers from a single process.
Date: 14 Mar 90 05:41:31 GMT
Sender: nntppost@uhnix1.uh.edu
To: unix-wizards@sem.brl.mil
The subj line says it; I want to set multiple timers from a single
process. Using alarm() & catching SIGALARM will permit only a single
timer. I need to set different values for the different timers
concurrently, and need the ability to restart them or to cancel
them.
My solution at the moment; each time I need a timer (a max of 4
will be needed concurrently), I spawn a child and store the pid
returned to uniquely identify thst timer. The child does a sleep(time)
for the required time. After which SIGCLD goes off. In my interrupt
routine of my main process, I track down which child expired and
determine which timer expired. Dirty, and difficult to manage, but
still workable.
As they said when tearing down the Berlin Wall, "Open to better
suggestions."
--ravi-
-----------------------------
From: Don Libes <libes@cme.nist.gov>
Subject: Re: Setting multiple timers from a single process.
Date: 14 Mar 90 20:43:36 GMT
To: unix-wizards@sem.brl.mil
In article <24200@uhnix1.uh.edu> rr@cs.uh.edu writes:
>The subj line says it; I want to set multiple timers from a single
>process. Using alarm() & catching SIGALARM will permit only a single
>timer. I need to set different values for the different timers
>
>My solution at the moment; [spawn child processes for each timer]
Simulate them by waiting for the shortest one, and keeping track of
the others yourself. I've done exactly this. Anyone who wants code
(4.2BSD) can mail me.
Just watch out for things like 1) a timer interrupting your timer
management code, 2) trying to cancel one this is in the process of
going off (or will be by the time you return), 3) getting a new timer
which is shorter than the current one you are waiting for, and 4) the
possibility of several being scheduled for the same time.
Don Libes libes@cme.nist.gov ...!uunet!cme-durer!libes
-----------------------------
From: Tom Stockfisch <tps@chem.ucsd.edu>
Subject: serious awk bug
Keywords: awk
Date: 14 Mar 90 06:02:46 GMT
To: unix-wizards@sem.brl.mil
The following awk script doesn't behave properly:
#! /bin/sh
awk '/^a*[^b]/ { print "1:", $0 }
/^a*b/ { print "2:", $0 }
'
When given the following input
b
ab
It produces the following output
2: b
1: ab
2: ab
Basically, the line "ab" should match only rule 2, but it matches both
rules. The following script:
#! /bin/sh
awk '/^a*[^b]c/ { print "1:", $0 }
/^a*bc/ { print "2:", $0 }
'
works, producing the output
2: bc
2: abc
The corresponding lex program works fine.
I have run the awk script with both the new awk and old awk, on both
a system V machine (silicon graphics iris) and a 4BSD machine (celerity)
and all seem to fail.
--
|| Tom Stockfisch, UCSD Chemistry tps@chem.ucsd.edu
-----------------------------
From: Mike McNally <m5@lynx.uucp>
Subject: Re: serious awk bug
Keywords: awk
Date: 14 Mar 90 15:25:00 GMT
To: unix-wizards@sem.brl.mil
tps@chem.ucsd.edu (Tom Stockfisch) writes:
>The following awk script doesn't behave properly:
>#! /bin/sh
>awk '/^a*[^b]/ { print "1:", $0 }
>/^a*b/ { print "2:", $0 }
>'
>When given the following input
>b
>ab
>It produces the following output
>2: b
>1: ab
>2: ab
>Basically, the line "ab" should match only rule 2 . . .
I disagree:
a*[^b] => <null>[^b] => <null>a
The a* is matching the empty string, and the [^b] is matching the a.
--
Mike McNally Lynx Real-Time Systems
uucp: {voder,athsys}!lynx!m5 phone: 408 370 2233
Where equal mind and contest equal, go.
-----------------------------
From: Randal Schwartz <merlyn@iwarp.intel.com>
Subject: Re: serious awk bug
Keywords: awk
Date: 14 Mar 90 17:12:58 GMT
Sender: news@iwarp.intel.com
Followup-To: poster
To: unix-wizards@sem.brl.mil
In article <702@chem.ucsd.EDU>, tps@chem (Tom Stockfisch) writes:
|
| The following awk script doesn't behave properly:
|
| #! /bin/sh
|
| awk '/^a*[^b]/ { print "1:", $0 }
| /^a*b/ { print "2:", $0 }
| '
|
| When given the following input
|
| b
| ab
|
| It produces the following output
|
| 2: b
| 1: ab
| 2: ab
|
| Basically, the line "ab" should match only rule 2, but it matches both
| rules.
[This doesn't belong in WIZARDS. Sorry.]
But, it *does* match rule 1! Look carefully. If you take zero 'a's,
and one 'not b', you can get line "ab"!
In Perl:
perl -ne 'print "1: $_" if /^a*[^b]/; print "2: $_" if /^a*b/;' <<EOF
b
ab
EOF
produces:
2: b
1: ab
2: ab
Just like awk. Amazing.
No problem.
Just another Perl and awk hacker,
--
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/
-----------------------------
From: Craig Leres <leres@ace.ee.lbl.gov>
Subject: Re: Raw disk I/O
Date: 14 Mar 90 06:58:26 GMT
Sender: usenet@helios.ee.lbl.gov
Followup-To: comp.unix.wizards
X-Local-Date: 13 Mar 90 22:58:26 PST
To: unix-wizards@sem.brl.mil
(Sorry to jump into this so late but it seems like I never have time to
read news.)
Folks interested in raw disk I/O will also be interested in the little
disk bench mark package we've thrown together. Eventually, I'd like to
it to include a complete tutorial on How To Tune Your Filesystem; for
now the (limited) documentation really only deals with how to measure
raw disk speeds.
The package is easy to use; the primary part is the "disktest" script
which does raw reads at block sizes ranging from 4k to 128k. There's a
simple line fitting program that allows you to munch "disktest" runs
down to the throughput (in KB/sec) and fixed overhead (in ms) numbers.
For example, I've measured 2094.07 KB/sec, 1.49 ms on my Sun 3/180
which runs SunOS 3.5 and has Fujitsu M2344's on an Interphase 4400
controller. There are also some scripts for use with xgraph.
The disktest package is available via anonymous ftp from the host
ftp.ee.lbl.gov (128.3.254.68) in the file disktest.shar.Z. As usual,
use binary mode for best results.
Craig
-----------------------------
From: Jonathan Hue <hue@netcom.uucp>
Subject: repeatability of select()
Date: 14 Mar 90 08:27:37 GMT
To: unix-wizards@sem.brl.mil
Under what conditions would the following code fragments not be
equivalent?
case #1:
n = select(nfds, rdset, wrset, exset, timeout_p);
case #2:
select(nfds, rdset, wrset, exset, timeout_p);
/* reset rdset, wrset, and exset to their original values */
...
n = select(nfds, rdset, wrset, exset, (struct timeval *) 0);
I'm interested in the behavior on any version of UNIX. Assume for the moment
that select() isn't getting interrupted by a signal or anything like that.
One case I can think of is HP-UX and a graphics display. You can detect
vertical retrace interrupts or blitter interrupts by setting the bit
corresponding to an open frame buffer in the exception mask. If you called it
again without reenabling the interrupt you wouldn't see the second one. Are
there any other cases like this?
-Jonathan
-----------------------------
From: Jonathan Hue <hue@netcom.uucp>
Subject: Re: repeatability of select() (correction)
Date: 14 Mar 90 17:57:59 GMT
To: unix-wizards@sem.brl.mil
In article <9156@netcom.UUCP> hue@netcom.UUCP (Jonathan Hue) writes:
>case #2:
> select(nfds, rdset, wrset, exset, timeout_p);
> /* reset rdset, wrset, and exset to their original values */
> ...
> n = select(nfds, rdset, wrset, exset, (struct timeval *) 0);
I screwed up, instead of that last line there it should have been something
like:
zero.tv_sec = 0;
zero.tv_usec = 0;
n = select(nfds, rdset, wrset, exset, &zero);
-Jonathan
-----------------------------
From: Steve Watt <steve@wattres.uucp>
Subject: Re: ADDING TO TAPE ARCHIVES - AHA1540+2150s
Date: 14 Mar 90 09:30:21 GMT
To: unix-wizards@sem.brl.mil
In article <262@netdev.Comsys.COM> root@netdev.Comsys.COM (Alex Huppenthal) writes:
< How can I add to the end of tar archives ? tar cv, tar cv works, but
< tape rewind, tape rfm, tar cv - does not!
<
< 1. Change the /etc/default/tar file to archive=/dev/nrct0
< 2. Change the /etc/default/tape file to /dev/nrct0
< 3. tar cv file1
< 4. tar cv file2
< 5. tape rewind
< 6. tape rfm - moves you to the end of file one
< 7. tape rfm - moves you to the end of file two
< 8. tape rfm - this is not a failure, it's a *feature* :-)
Actually, this moves you beyond the end of the file mark, because the previous
tape rfm leaves it at the file mark.
< 9. tar cv file3
< 10. tape rewind
< 11. tape rfm
< 12. tape rfm
< 13. tape rfm - now you are positioned at the end of the second file.
< 14. tar tvf ( or xvf ) /dev/rct0 ( can you beleive this? I can't )
< 15. THIS WORKS..... ^^^^--- notice *rct0* not nrct0, - ask SCO why!
It doesn't matter which you choose, unless you want to add another file after
this one. The nrct driver means "don't rewind _ON_CLOSE_". Only use the
rct driver if you want the tape rewound after each close.
[minor (probably unwarranted; most are) flame against SCO removed]
You could, of course use "tar rv files files files", and get them added on to
the end of the current archive, so you didn't have to run tar 3 times to get
all the data off of the tape.
--
Steve Watt
...!claris!wattres!steve wattres!steve@claris.com also works
If you torture your data long enough, it'll eventually confess.
-----------------------------
From: "Dr A. N. Walker" <anw@maths.nott.ac.uk>
Subject: Re: Dr David G Korn to speak at SVNet
Date: 14 Mar 90 17:03:47 GMT
To: unix-wizards@sem.brl.mil
In article <1990Mar11.160403.27949@sobeco.com> roe@sobeco.com
(r.peterson) writes:
>And even more to do with the fact that Bourne used the preprocessor
>to turn C into a bizarre pascal-lookalike. Truly the most difficult
>code I've ever tried to modify.
Actually, he used it to turn an Algol lookalike [not very!]
into C. Some of us old-timers found it quite readable. I've seen
much worse code over the years.
--
Andy Walker, Maths Dept., Nott'm Univ., UK.
anw@maths.nott.ac.uk
-----------------------------
From: Doug Gwyn <gwyn@smoke.brl.mil>
Subject: Re: Large Unix, SYS5.4 on Unisys
Date: 15 Mar 90 00:34:20 GMT
To: unix-wizards@sem.brl.mil
In article <22750@adm.BRL.MIL> archunix@stl-08sima.army.mil (Bernie J. Potter) writes:
>In addition, I have been asked to locate alternate sources
>(besides Unisys) for a System V Release 4 based operating
>system for a Unisys 5000/80 machine. We are unable to
>upgrade to Release 4 under our current Unisys contract
>and would like to find another source for doing so.
By far your best source for an operating system would be the vendor,
even if it means writing a separate procurement action (which you would
have to do anyway no matter what the source of the off-contract software).
Since UNIX System V Release 4.0 has just been released, it may have not
yet been ported to your hardware even if the vendor plans to do so.
If Unisys tells you definitely that they have no plans to upgrade their
current OS to SVR4.0 (quite apart from considerations of the DA MINIS
contract), then try contacting Arete who as I recall actually developed
the system you are now using (resold by Unisys). I'm not sure that Arete
is still in business under the same name, however; this industry changes
its infrastructure too frequently for me to keep up with such details.
-----------------------------
From: Ed Arnold <era@ncar.ucar.edu>
Subject: mac postscript in ditroff input?
Date: 14 Mar 90 22:46:33 GMT
Sender: news@ncar.ucar.edu
To: unix-wizards@sem.brl.mil
I'm interested in corresponding with anyone who has succeeded in merging
postscript generated by Mac applications such as MacDraw or Illustrator,
into ditroff input, to get merged ditroff text & Apple postscript graphics
on the same page.
I've tried this using:
TranScript 2.1 (psdit)
LaserPrep 5.2
SunOS 4.0.3
Apple LaserWriter Plus (sort of works)
Imagen 2308 with ultrascript and Apple dictionary dictv52.ps
(doesn't work; quits with error message)
I followed the suggestions given on the psdit man page to merge in the
postscript, and various permutations thereof, but ditroff text is either
lost, or appears on the next page, when printing to the LaserWriter.
Adobe doesn't seem to know whether this is possible; but they won't talk
with me anyway, since I'm not an Adobe developer. I'm not particularly
eager to learn the entire Apple dictionary. :-(
--
Ed Arnold * NCAR * POB 3000, Boulder, CO 80307-3000 * 303-497-1253(w)
era@ncar.ucar.edu [128.117.64.4] * era@ncario.bitnet * era@ncar.uucp
"See, the human mind is kind of like ... a pinata. When it breaks open,
there's a lot of surprises inside." --Jane Wagner/Lily Tomlin
-----------------------------
From: Mike Thompson <yohn@tumult.sgi.com>
Subject: Re: Setting the access/modify time on a file
Date: 14 Mar 90 23:00:46 GMT
Sender: yohn@tumult.sgi.com
To: unix-wizards@sem.brl.mil
In article <1413@watserv1.waterloo.edu>, tom@mims-iris.waterloo.edu (Tom Haapanen) writes:
> I wish to update a file (with an advisory lock), and then to close it,
> setting the access and modify times to (almost) the same time. Here
> is what I'm attempting:
>
> FILE *fp;
> long times;
>
> fp = fopen("filename", "w");
> flock(fileno(fp), LOCK_EX);
>
> ... much i/o to the file ...
>
> fflush(fp);
> times[1] = time(×[0]) - (long)2;
> utime(mailfile, times);
>
> flock(fileno(fp), LOCK_UN);
> fclose(fp);
>
> Now, at what point does the modify time get set? the utime() call appears
> to set the access time, but the modify time appears to be set AGAIN after
> the access time. Where SHOULD it get set? And what should I do to make
> sure that my access time > modify time?
>
> The OS is IRIX 3.2 -- aka System V.3. Thanks for any and all replies!
This is a bug in 3.2 -- the Extent File System routine which is deallocating
preallocated file blocks on close is (mistakenly) forcing the modify time
to be set (to the close time). It has been fixed for the upcoming release.
For now, reopen the file after the fclose, and *then* call utime and
reclose the file. The deallocation routine will not be called (actually,
will return without doing anything) since there had been no file activity
since the open.
Michael Thompson
-----------------------------
End of UNIX-WIZARDS Digest
**************************markw@hpdmd48.HP.COM (Mark Wolfe) (03/24/90)
/ hpdmd48:comp.unix.wizards / postmaster@sandia.gov (SMTP MAILER) / 2:52 pm Mar 18, 1990 /
----Reason for mail failure follows----
Sending mail to <math!ckaul@cs.sandia.gov> :
Could not be delivered for three days.
----Transcript of message follows----
Date: 15 Mar 90 07:25:00 MST
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V9#094
To: "math!ckaul" <math!ckaul@cs.sandia.gov>
Return-Path: <incoming-unix-wizards-request@sandia.gov>
Received: from SEM.BRL.MIL by sandia.gov with SMTP ;
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Date: Thu, 15 Mar 90 05:45:04 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V9#094
Message-ID: <9003150545.aa06456@SEM.BRL.MIL>
UNIX-WIZARDS Digest Thu, 15 Mar 1990 V9#094
Today's Topics:
System V kernel panic not syncing
Re: Which is more portable: stty < or stty >
Use of ssignal() in Sys V.
Re: Use of ssignal() in Sys V.
Setting multiple timers from a single process.
Re: Setting multiple timers from a single process.
serious awk bug
Re: serious awk bug
Re: Raw disk I/O
repeatability of select()
Re: repeatability of select() (correction)
Re: ADDING TO TAPE ARCHIVES - AHA1540+2150s
Re: Dr David G Korn to speak at SVNet
Re: Large Unix, SYS5.4 on Unisys
mac postscript in ditroff input?
Re: Setting the access/modify time on a file
-----------------------------------------------------------------
From: neal@mnopltd.uucp
Subject: System V kernel panic not syncing
Date: 13 Mar 90 15:03:53 GMT
Posted: Tue Mar 13 10:03:53 1990
To: unix-wizards@sem.brl.mil
->Anyone know how to get the SCO UNIX System V/386 r3.2 kernel
->to do sync when it panics so fsck is happy when you start up again?
->
->I'm told that BSD can do this, and I have a use for this while
->running this OS on a 'beta' CPU which will cause a panic under
->certain circumstances.
Wait a second... This doesn't make sense. Panics are frequently situations
where the kernel code is not confident to continue processing. Doing a
sync in this situation is like painting over rust. For any degree of system
stability you need to fsck and "take your medecine"...
------------------------------------------------------------------------------
Neal Rhodes MNOP Ltd (404)- 972-5430
President Lilburn (atlanta) GA 30247 Fax: 978-4741
uunet!emory!jdyx!mnopltd!neal Or uunet!gatech!stiatl!mnopltd!neal
------------------------------------------------------------------------------
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: Which is more portable: stty < or stty >
Date: 13 Mar 90 19:18:10 GMT
To: unix-wizards@sem.brl.mil
>Currently, 4.0.3 defaults to using the native stty. According to a
>Sun rep, the next release (4.1) will default to the System V version,
>although the next version (5.0) will not have any "preference" (his
>word, which he could not explain). It actually sounded to me like
>that have simply not yet decided.
It sounds to *me* like your Sun rep is seriously confused. (If he
couldn't explain his use of "preference", why was he using it? Yeesh.)
As of when I left Sun, the intent was to have the BSD environment be the
"default", in the sense that if the environment variable PATH isn't set,
the "default" path will *not* have "/usr/5bin" before "/bin" or
"/usr/bin" (BTW, in SunOS 4.x, there's no point in having "/bin" in your
path at all, if you have "/usr/bin" there - "/bin" is just a symlink to
"/usr/bin").
"5.0" has not necessarily been chosen as the name for Sun's System V
Release 4-based release. If the rep was thinking of that release, the
"stty" in "/usr/bin" or wherever will, as one would expect, have the
System V behavior. I don't know if System V Release 4 from AT&T will
have a "/usr/ucb/stty" that provides the BSD behavior or not; even if
they don't, Sun might put one into their release.
>Will POSIX provide an answer, or perhaps, provide a stty90 which has a
>real interface?
According to my copy of Draft 9 of 1003.2:
The "stty" utility sets or reports on terminal I/O
characteristics for the device that is its standard input.
I don't think this is the latest draft, but I'd be surprised if they
changed this in a later draft.
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: Which is more portable: stty < or stty >
Date: 13 Mar 90 19:22:38 GMT
To: unix-wizards@sem.brl.mil
>The former is the 7th Ed. UNIX and 4BSD behavior.
>System V assumes you may want to redirect the output somewhere other
>than the terminal being probed.
You can do that with the V7 and BSD one, it's just more painful - you
have to redirect the standard error.
The S5 behavior is a bit more natural, in that its output goes to, well,
the standard output; the only reason I can see for the V7 behavior is
that it makes it possible to set the modes on a tty other than one on
which you're logged in without being super-user, since traditionally
ttys have been publicly writable but not publicly readable.
While in some environments this would be considered a feature ("Hey,
Jane, I screwed up my tty settings; could you fix them for me? I'm on
'/dev/tty73'."), it would be considered a problem in others
("stty erase 's' kill 't' intr 'y' >/dev/tty73").
Given that in 4.3BSD and now S5R4 ttys are *not* publicly writeable, but
writeable only by a special group, to which programs like "write" are
set-GID (so that you can't send things like the "transmit screen to
host" escape sequence to somebody else's terminal), the V7 behavior
doesn't buy you anything any more.
-----------------------------
From: "Frank I. Reiter" <frank@rsoft.bc.ca>
Subject: Re: Which is more portable: stty < or stty >
Date: 14 Mar 90 15:40:19 GMT
To: unix-wizards@sem.brl.mil
In article <3354@muffin.cme.nist.gov> libes@cme.nist.gov (Don Libes) writes:
>According to the man page (SunOS 4.0.3) ...
>The native SunOS stty(1) acts on the device that is the current stdout
>while their System V stty acts on the device that is the current stdin.
Why not both? stty </dev/x >/dev/x
--
_____________________________________________________________________________
Frank I. Reiter UUCP: {uunet,ubc-cs}!van-bc!rsoft!frank
Reiter Software Inc. frank@rsoft.bc.ca, a2@mindlink.UUCP
Surrey, British Columbia BBS: Mind Link @ (604)576-1214, login as Guest
-----------------------------
From: Johan Vromans <jv@mh.nl>
Subject: Re: Which is more portable: stty < or stty >
Date: 14 Mar 90 20:08:58 GMT
Sender: news@mhres.mh.nl
To: unix-wizards@sem.brl.mil
In article <JV.90Mar13162312@squirrel.mh.nl> jv@mh.nl (Johan Vromans) writes:
`[SystemV:]
`
` STTY_FLAGS=`stty -g < /dev/tty`
` sane() { stty ${STTY_FLAGS}; }
`
`You can't do this from your BSD .login .
To which andyb@coat.com (Andy Behrens) replies:
` STTY_OUTPUT=`stty 2>&1 >/dev/tty`
`
`Of course, BSD doesn't support 'stty -g', but that's another issue.
My BSD system (Ultrix) does. But I mentioned a '.login' file for Csh.
Maarten "als iemand 't kan, is hij het wel" Lithmaat replies:
`Indeed. But if BSD's stty(1) would have had `-g', you *could* have done:
`
` set STTY_FLAGS="`(stty -g > /dev/tty) |& cat`"
Now this works.
Johan
--
Johan Vromans jv@mh.nl via internet backbones
Multihouse Automatisering bv uucp: ..!{uunet,hp4nl}!mh.nl!jv
Doesburgweg 7, 2803 PL Gouda, The Netherlands phone/fax: +31 1820 62944/62500
------------------------ "Arms are made for hugging" -------------------------
-----------------------------
From: Ravi Ramachandran <rr@csuna.cs.uh.edu>
Subject: Use of ssignal() in Sys V.
Date: 14 Mar 90 05:28:16 GMT
Sender: nntppost@uhnix1.uh.edu
To: unix-wizards@sem.brl.mil
The man pages for ssignal & gsignal on Sys V are as succint as usual.
I tried looking up a few adv. Unix books, but none of them ever mention
ssignal. The way I have used it is to use ssignal to initialize the
software signal, and then use gsignal to raise it. But this seems more
like another version of using setjmp() or calling a procedure. Is there
any use for ssignal()? Can I use it between processes (I tried it & it
didn't seem to work)? I know the man pages says that the C compiler uses
it. But unless there is some way a parallel thread can send a signal,
it does not seem too useful.
Thanx for shedding any light (I SAID BUD LITE),
--ravi-
-----------------------------
From: Doug Gwyn <gwyn@smoke.brl.mil>
Subject: Re: Use of ssignal() in Sys V.
Date: 15 Mar 90 00:24:18 GMT
To: unix-wizards@sem.brl.mil
In article <24199@uhnix1.uh.edu> rr@cs.uh.edu writes:
>Is there any use for ssignal()? Can I use it between processes ...?
While one can figure out ways to use ssignal/gsignal, they are not
essential. Certainly they cannot be used for IPC, only within one
process. I suggest never using them.
-----------------------------
From: Ravi Ramachandran <rr@csuna.cs.uh.edu>
Subject: Setting multiple timers from a single process.
Date: 14 Mar 90 05:41:31 GMT
Sender: nntppost@uhnix1.uh.edu
To: unix-wizards@sem.brl.mil
The subj line says it; I want to set multiple timers from a single
process. Using alarm() & catching SIGALARM will permit only a single
timer. I need to set different values for the different timers
concurrently, and need the ability to restart them or to cancel
them.
My solution at the moment; each time I need a timer (a max of 4
will be needed concurrently), I spawn a child and store the pid
returned to uniquely identify thst timer. The child does a sleep(time)
for the required time. After which SIGCLD goes off. In my interrupt
routine of my main process, I track down which child expired and
determine which timer expired. Dirty, and difficult to manage, but
still workable.
As they said when tearing down the Berlin Wall, "Open to better
suggestions."
--ravi-
-----------------------------
From: Don Libes <libes@cme.nist.gov>
Subject: Re: Setting multiple timers from a single process.
Date: 14 Mar 90 20:43:36 GMT
To: unix-wizards@sem.brl.mil
In article <24200@uhnix1.uh.edu> rr@cs.uh.edu writes:
>The subj line says it; I want to set multiple timers from a single
>process. Using alarm() & catching SIGALARM will permit only a single
>timer. I need to set different values for the different timers
>
>My solution at the moment; [spawn child processes for each timer]
Simulate them by waiting for the shortest one, and keeping track of
the others yourself. I've done exactly this. Anyone who wants code
(4.2BSD) can mail me.
Just watch out for things like 1) a timer interrupting your timer
management code, 2) trying to cancel one this is in the process of
going off (or will be by the time you return), 3) getting a new timer
which is shorter than the current one you are waiting for, and 4) the
possibility of several being scheduled for the same time.
Don Libes libes@cme.nist.gov ...!uunet!cme-durer!libes
-----------------------------
From: Tom Stockfisch <tps@chem.ucsd.edu>
Subject: serious awk bug
Keywords: awk
Date: 14 Mar 90 06:02:46 GMT
To: unix-wizards@sem.brl.mil
The following awk script doesn't behave properly:
#! /bin/sh
awk '/^a*[^b]/ { print "1:", $0 }
/^a*b/ { print "2:", $0 }
'
When given the following input
b
ab
It produces the following output
2: b
1: ab
2: ab
Basically, the line "ab" should match only rule 2, but it matches both
rules. The following script:
#! /bin/sh
awk '/^a*[^b]c/ { print "1:", $0 }
/^a*bc/ { print "2:", $0 }
'
works, producing the output
2: bc
2: abc
The corresponding lex program works fine.
I have run the awk script with both the new awk and old awk, on both
a system V machine (silicon graphics iris) and a 4BSD machine (celerity)
and all seem to fail.
--
|| Tom Stockfisch, UCSD Chemistry tps@chem.ucsd.edu
-----------------------------
From: Mike McNally <m5@lynx.uucp>
Subject: Re: serious awk bug
Keywords: awk
Date: 14 Mar 90 15:25:00 GMT
To: unix-wizards@sem.brl.mil
tps@chem.ucsd.edu (Tom Stockfisch) writes:
>The following awk script doesn't behave properly:
>#! /bin/sh
>awk '/^a*[^b]/ { print "1:", $0 }
>/^a*b/ { print "2:", $0 }
>'
>When given the following input
>b
>ab
>It produces the following output
>2: b
>1: ab
>2: ab
>Basically, the line "ab" should match only rule 2 . . .
I disagree:
a*[^b] => <null>[^b] => <null>a
The a* is matching the empty string, and the [^b] is matching the a.
--
Mike McNally Lynx Real-Time Systems
uucp: {voder,athsys}!lynx!m5 phone: 408 370 2233
Where equal mind and contest equal, go.
-----------------------------
From: Randal Schwartz <merlyn@iwarp.intel.com>
Subject: Re: serious awk bug
Keywords: awk
Date: 14 Mar 90 17:12:58 GMT
Sender: news@iwarp.intel.com
Followup-To: poster
To: unix-wizards@sem.brl.mil
In article <702@chem.ucsd.EDU>, tps@chem (Tom Stockfisch) writes:
|
| The following awk script doesn't behave properly:
|
| #! /bin/sh
|
| awk '/^a*[^b]/ { print "1:", $0 }
| /^a*b/ { print "2:", $0 }
| '
|
| When given the following input
|
| b
| ab
|
| It produces the following output
|
| 2: b
| 1: ab
| 2: ab
|
| Basically, the line "ab" should match only rule 2, but it matches both
| rules.
[This doesn't belong in WIZARDS. Sorry.]
But, it *does* match rule 1! Look carefully. If you take zero 'a's,
and one 'not b', you can get line "ab"!
In Perl:
perl -ne 'print "1: $_" if /^a*[^b]/; print "2: $_" if /^a*b/;' <<EOF
b
ab
EOF
produces:
2: b
1: ab
2: ab
Just like awk. Amazing.
No problem.
Just another Perl and awk hacker,
--
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/
-----------------------------
From: Craig Leres <leres@ace.ee.lbl.gov>
Subject: Re: Raw disk I/O
Date: 14 Mar 90 06:58:26 GMT
Sender: usenet@helios.ee.lbl.gov
Followup-To: comp.unix.wizards
X-Local-Date: 13 Mar 90 22:58:26 PST
To: unix-wizards@sem.brl.mil
(Sorry to jump into this so late but it seems like I never have time to
read news.)
Folks interested in raw disk I/O will also be interested in the little
disk bench mark package we've thrown together. Eventually, I'd like to
it to include a complete tutorial on How To Tune Your Filesystem; for
now the (limited) documentation really only deals with how to measure
raw disk speeds.
The package is easy to use; the primary part is the "disktest" script
which does raw reads at block sizes ranging from 4k to 128k. There's a
simple line fitting program that allows you to munch "disktest" runs
down to the throughput (in KB/sec) and fixed overhead (in ms) numbers.
For example, I've measured 2094.07 KB/sec, 1.49 ms on my Sun 3/180
which runs SunOS 3.5 and has Fujitsu M2344's on an Interphase 4400
controller. There are also some scripts for use with xgraph.
The disktest package is available via anonymous ftp from the host
ftp.ee.lbl.gov (128.3.254.68) in the file disktest.shar.Z. As usual,
use binary mode for best results.
Craig
-----------------------------
From: Jonathan Hue <hue@netcom.uucp>
Subject: repeatability of select()
Date: 14 Mar 90 08:27:37 GMT
To: unix-wizards@sem.brl.mil
Under what conditions would the following code fragments not be
equivalent?
case #1:
n = select(nfds, rdset, wrset, exset, timeout_p);
case #2:
select(nfds, rdset, wrset, exset, timeout_p);
/* reset rdset, wrset, and exset to their original values */
...
n = select(nfds, rdset, wrset, exset, (struct timeval *) 0);
I'm interested in the behavior on any version of UNIX. Assume for the moment
that select() isn't getting interrupted by a signal or anything like that.
One case I can think of is HP-UX and a graphics display. You can detect
vertical retrace interrupts or blitter interrupts by setting the bit
corresponding to an open frame buffer in the exception mask. If you called it
again without reenabling the interrupt you wouldn't see the second one. Are
there any other cases like this?
-Jonathan
-----------------------------
From: Jonathan Hue <hue@netcom.uucp>
Subject: Re: repeatability of select() (correction)
Date: 14 Mar 90 17:57:59 GMT
To: unix-wizards@sem.brl.mil
In article <9156@netcom.UUCP> hue@netcom.UUCP (Jonathan Hue) writes:
>case #2:
> select(nfds, rdset, wrset, exset, timeout_p);
> /* reset rdset, wrset, and exset to their original values */
> ...
> n = select(nfds, rdset, wrset, exset, (struct timeval *) 0);
I screwed up, instead of that last line there it should have been something
like:
zero.tv_sec = 0;
zero.tv_usec = 0;
n = select(nfds, rdset, wrset, exset, &zero);
-Jonathan
-----------------------------
From: Steve Watt <steve@wattres.uucp>
Subject: Re: ADDING TO TAPE ARCHIVES - AHA1540+2150s
Date: 14 Mar 90 09:30:21 GMT
To: unix-wizards@sem.brl.mil
In article <262@netdev.Comsys.COM> root@netdev.Comsys.COM (Alex Huppenthal) writes:
< How can I add to the end of tar archives ? tar cv, tar cv works, but
< tape rewind, tape rfm, tar cv - does not!
<
< 1. Change the /etc/default/tar file to archive=/dev/nrct0
< 2. Change the /etc/default/tape file to /dev/nrct0
< 3. tar cv file1
< 4. tar cv file2
< 5. tape rewind
< 6. tape rfm - moves you to the end of file one
< 7. tape rfm - moves you to the end of file two
< 8. tape rfm - this is not a failure, it's a *feature* :-)
Actually, this moves you beyond the end of the file mark, because the previous
tape rfm leaves it at the file mark.
< 9. tar cv file3
< 10. tape rewind
< 11. tape rfm
< 12. tape rfm
< 13. tape rfm - now you are positioned at the end of the second file.
< 14. tar tvf ( or xvf ) /dev/rct0 ( can you beleive this? I can't )
< 15. THIS WORKS..... ^^^^--- notice *rct0* not nrct0, - ask SCO why!
It doesn't matter which you choose, unless you want to add another file after
this one. The nrct driver means "don't rewind _ON_CLOSE_". Only use the
rct driver if you want the tape rewound after each close.
[minor (probably unwarranted; most are) flame against SCO removed]
You could, of course use "tar rv files files files", and get them added on to
the end of the current archive, so you didn't have to run tar 3 times to get
all the data off of the tape.
--
Steve Watt
...!claris!wattres!steve wattres!steve@claris.com also works
If you torture your data long enough, it'll eventually confess.
-----------------------------
From: "Dr A. N. Walker" <anw@maths.nott.ac.uk>
Subject: Re: Dr David G Korn to speak at SVNet
Date: 14 Mar 90 17:03:47 GMT
To: unix-wizards@sem.brl.mil
In article <1990Mar11.160403.27949@sobeco.com> roe@sobeco.com
(r.peterson) writes:
>And even more to do with the fact that Bourne used the preprocessor
>to turn C into a bizarre pascal-lookalike. Truly the most difficult
>code I've ever tried to modify.
Actually, he used it to turn an Algol lookalike [not very!]
into C. Some of us old-timers found it quite readable. I've seen
much worse code over the years.
--
Andy Walker, Maths Dept., Nott'm Univ., UK.
anw@maths.nott.ac.uk
-----------------------------
From: Doug Gwyn <gwyn@smoke.brl.mil>
Subject: Re: Large Unix, SYS5.4 on Unisys
Date: 15 Mar 90 00:34:20 GMT
To: unix-wizards@sem.brl.mil
In article <22750@adm.BRL.MIL> archunix@stl-08sima.army.mil (Bernie J. Potter) writes:
>In addition, I have been asked to locate alternate sources
>(besides Unisys) for a System V Release 4 based operating
>system for a Unisys 5000/80 machine. We are unable to
>upgrade to Release 4 under our current Unisys contract
>and would like to find another source for doing so.
By far your best source for an operating system would be the vendor,
even if it means writing a separate procurement action (which you would
have to do anyway no matter what the source of the off-contract software).
Since UNIX System V Release 4.0 has just been released, it may have not
yet been ported to your hardware even if the vendor plans to do so.
If Unisys tells you definitely that they have no plans to upgrade their
current OS to SVR4.0 (quite apart from considerations of the DA MINIS
contract), then try contacting Arete who as I recall actually developed
the system you are now using (resold by Unisys). I'm not sure that Arete
is still in business under the same name, however; this industry changes
its infrastructure too frequently for me to keep up with such details.
-----------------------------
From: Ed Arnold <era@ncar.ucar.edu>
Subject: mac postscript in ditroff input?
Date: 14 Mar 90 22:46:33 GMT
Sender: news@ncar.ucar.edu
To: unix-wizards@sem.brl.mil
I'm interested in corresponding with anyone who has succeeded in merging
postscript generated by Mac applications such as MacDraw or Illustrator,
into ditroff input, to get merged ditroff text & Apple postscript graphics
on the same page.
I've tried this using:
TranScript 2.1 (psdit)
LaserPrep 5.2
SunOS 4.0.3
Apple LaserWriter Plus (sort of works)
Imagen 2308 with ultrascript and Apple dictionary dictv52.ps
(doesn't work; quits with error message)
I followed the suggestions given on the psdit man page to merge in the
postscript, and various permutations thereof, but ditroff text is either
lost, or appears on the next page, when printing to the LaserWriter.
Adobe doesn't seem to know whether this is possible; but they won't talk
with me anyway, since I'm not an Adobe developer. I'm not particularly
eager to learn the entire Apple dictionary. :-(
--
Ed Arnold * NCAR * POB 3000, Boulder, CO 80307-3000 * 303-497-1253(w)
era@ncar.ucar.edu [128.117.64.4] * era@ncario.bitnet * era@ncar.uucp
"See, the human mind is kind of like ... a pinata. When it breaks open,
there's a lot of surprises inside." --Jane Wagner/Lily Tomlin
-----------------------------
From: Mike Thompson <yohn@tumult.sgi.com>
Subject: Re: Setting the access/modify time on a file
Date: 14 Mar 90 23:00:46 GMT
Sender: yohn@tumult.sgi.com
To: unix-wizards@sem.brl.mil
In article <1413@watserv1.waterloo.edu>, tom@mims-iris.waterloo.edu (Tom Haapanen) writes:
> I wish to update a file (with an advisory lock), and then to close it,
> setting the access and modify times to (almost) the same time. Here
> is what I'm attempting:
>
> FILE *fp;
> long times;
>
> fp = fopen("filename", "w");
> flock(fileno(fp), LOCK_EX);
>
> ... much i/o to the file ...
>
> fflush(fp);
> times[1] = time(×[0]) - (long)2;
> utime(mailfile, times);
>
> flock(fileno(fp), LOCK_UN);
> fclose(fp);
>
> Now, at what point does the modify time get set? the utime() call appears
> to set the access time, but the modify time appears to be set AGAIN after
> the access time. Where SHOULD it get set? And what should I do to make
> sure that my access time > modify time?
>
> The OS is IRIX 3.2 -- aka System V.3. Thanks for any and all replies!
This is a bug in 3.2 -- the Extent File System routine which is deallocating
preallocated file blocks on close is (mistakenly) forcing the modify time
to be set (to the close time). It has been fixed for the upcoming release.
For now, reopen the file after the fclose, and *then* call utime and
reclose the file. The deallocation routine will not be called (actually,
will return without doing anything) since there had been no file activity
since the open.
Michael Thompson
-----------------------------
End of UNIX-WIZARDS Digest
**************************
----------postmaster@sandia.gov (SMTP MAILER) (06/06/90)
----Reason for mail failure follows----
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Could not be delivered for three days.
----Transcript of message follows----
Date: 3 Jun 90 06:49:00 MDT
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#049
To: "ckaul" <ckaul%math@cs.sandia.gov>
Return-Path: <incoming-unix-wizards-request@sandia.gov>
Received: from SEM.BRL.MIL by sandia.gov with SMTP ;
Sun, 3 Jun 90 06:30:17 MDT
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Date: Sun, 03 Jun 90 05:45:05 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#049
Message-ID: <9006030545.aa23376@SEM.BRL.MIL>
UNIX-WIZARDS Digest Sun, 03 Jun 1990 V10#049
Today's Topics:
Re: C0WABUNGA!!
To which devices does select apply?
Re: REVISED: How do I send e-mail to lots of users at a remote unix site?
Re: How can a parent find out if one of its children is still alive
Re: lpadmin(8) question
Re: ksh discriminates background processes
Re: SEX! or, how do I mail to a lot of unix users?
Re: ksh discriminates background processes
Init S on System V 3.2
need help with 'curses'
Re: ksh discriminates background processes
Lex man page flame (was Re: Lex and initial start conditions)
can Sys. V Rel. 3.2 support > 16MB RAM when can only DMA to <= 16MB?
Re: can Sys. V Rel. 3.2 support > 16MB RAM when can only DMA to <= 16MB?
Re: Removing garbage files
time dep login
-----------------------------------------------------------------
From: "Gil Pilz@Eng@Banyan" <gil@banyan.uucp>
Subject: Re: C0WABUNGA!!
Keywords: stuffed-shirt
Date: 1 Jun 90 22:44:32 GMT
To: unix-wizards@sem.brl.mil
In article <574@lad.scs.com> lad@lad.scs.com (Lawrence A. Deleski) writes:
>
>From article <901508516356BIFF@BIFFVM.BIT.NET>, by BIFF@BIFFVM.BIT.NET (THE
>BIFFMAN COMETH):
>> HIYA D00DS!! ICUZ MY BBROTHER <--BIG BROTHER, NEET HUH? WUZ BBSITTING ME
>AND MY> MOM WULD KILL HIM IF ANYTING HAPENED TO ME. THEES SHUR R
>Is there anything we can do about this 'dude'? He's cross-posted to every
>damn group he could. I really hate this type of trash.
one . . two . . three . . four . . "Lighten up Lawrence !"
It's a *joke* son ! Get it !?
"when Jim calls out the infantry
to save the likes of you and me
and planes are falling from they sky
then there's no need to wonder why
it's BIFF !"
Gilbert Pilz Jr. "sick, and proud of it" gil@banyan.com
-----------------------------
From: "Aryeh M. Weiss" <aryeh@eddie.mit.edu>
Subject: To which devices does select apply?
Keywords: select pipes
Date: 2 Jun 90 13:42:31 GMT
To: unix-wizards@sem.brl.mil
What devices does select apply? I know select() is designed to be used with
serial and event devices, but does it apply to pipes or ordinary files?
Under SCO Xenix V/386 R2.3.2 select() *always* indicates data is available
from a pipe, including empty pipes. Is there a standard for select()'s
behavior on pipes?
--
-----------------------------
From: Larry McVoy <lm@snafu.sun.com>
Subject: Re: REVISED: How do I send e-mail to lots of users at a remote unix site?
Date: 31 May 90 19:59:39 GMT
Sender: news@sun.eng.sun.com
Followup-To: comp.unix.questions
To: unix-wizards@sem.brl.mil
In article <900531093547.30e0dca3@Csa2.LBL.Gov> thermal%solgel.hepnet@CSA2.LBL.GOV writes:
>I would like to be able to send a mail message to all the users on
>ANOTHER unix machine via Internet. Of course, I could do it the long
>and tedious way, that is, by sending a mail message to each user, one
>at a time. Is there a quicker way? (it seems to me there could be two
>or three different ways, such as setting up a mailing list file on my
>machine which will automatically mail the message to all on the list,
>or sending one message to the remote machine and somehow instruct it
>to distribute the message to all the users). Obviously, I'm not a
>unix guru or wizard, so make your explanation understandable, please.
You'll have to get cooperation from the remote machine. Let's assume that
you are mailing to a remote machine that runs sendmail. Then you can
get the remote admin to edit /etc/aliases and add a line like:
kernel: lm,auspex!guy,shannon,limes,glenn,dave@cs.wisc.edu
Then if you mail kernel@remote.host.whatever the message will be exploded
on remote.host.whatever instead of the local host.
You may need to run "newaliases" which massages the alias file into a
database that sendmail uses.
If you are sending to a remote host that doesn't run sendmail or any other
mailer that provides an aliasing service then I don't know what you can
do.
This message is more appropriate for comp.unix.questions so I've directed
follow ups there.
---
Larry McVoy, Sun Microsystems (415) 336-7627 ...!sun!lm or lm@sun.com
-----------------------------
From: Tom Armistead <toma@ozdaltx.uucp>
Subject: Re: How can a parent find out if one of its children is still alive
Date: 2 Jun 90 05:14:48 GMT
To: unix-wizards@sem.brl.mil
In article <30408@cup.portal.com>, DeadHead@cup.portal.com (Bruce M Ong) writes:
> I am sure there is a very easy way to do this, but I just havent
> figured this one out:
>
> How can a parent find out if one of its children is still alive
> or not without
.....
If you have the process id of the child you can use kill(2) to find out if
it is still there.
i.e.: if( kill( child_pid, 0 ) == -1 )
puts( "The child is dead" );
Signal 0 is called the NULL signal and is used to validate a process id, no
signal is actually sent to the destination process.
Will this do it for you?
Tom
--
-------------------------------
{uunet,smu}!sulaco!ozdaltx!toma (Tom Armistead @ Garland, Texas)
{uunet,smu}!sulaco!ozdaltx!swsrv1!toma
-----------------------------
From: "Conor P. Cahill" <cpcahil@virtech.uucp>
Subject: Re: lpadmin(8) question
Keywords: lp systemv
Date: 2 Jun 90 03:41:51 GMT
To: unix-wizards@sem.brl.mil
In article <453@van-bc.UUCP> sl@van-bc.UUCP (Stuart Lynne) writes:
>In the man page for lpadmin:
>
> -vdevice ..... Note that there is nothng to stop a system
> manager from associating the same device with more
> than one printer.
>
>Does this mean that there is nothing to stop you from doing this so don't do
>it?
No. What it means is that you can do it, but you must set things up so
that they work correctly. This has been used lots of times to have a
printer with several kinds of paper that can be loaded and each type
of paper will get it's own queue while the device for all of the queues
is the same.
In this scenario, the system administrator must enable 1 and only 1 of
the queues at the same time (hopefully just after he placed the appropriate
paper into the printer).
--
Conor P. Cahill (703)430-9247 Virtual Technologies, Inc.,
uunet!virtech!cpcahil 46030 Manekin Plaza, Suite 160
Sterling, VA 22170
-----------------------------
From: Bill Irwin <bill@twg.bc.ca>
Subject: Re: lpadmin(8) question
Keywords: lp systemv
Date: 2 Jun 90 10:19:42 GMT
Expires:
Sender:
Followup-To:
To: unix-wizards@sem.brl.mil
In article <453@van-bc.UUCP> sl@van-bc.UUCP (Stuart Lynne) writes:
>Which is what I need to do. I have two different packages that want to
>install specialized lp destinations with appropriate filters. Can I install
>both and have lp figure out how multiplex the requests for the two
>destinations to the one physical printer?
>
>Or will I have to hack the two interfaces together and add options?
>
>What I wanted was for file1 to be printed, followed by file2. What I got was
>file1 intermingled with file2 being printed.
I have had this same problem. I have one printer that is used for four
lp destinations. When jobs are queued to two or more of the destinations
at the same time, you get garbage. The solution I came up with works
very well. It involves adding some lines to the models which will check
to see if there is a lock file in place for this physical printer, wait
if there is; make a lock file if there isn't; print the job(s); then
remove the lock. I have attached excerpts from one of my models.
: computer_pr
# Looks for print jobs on any printer on the same port as
# computer_pr, and waits until there are no jobs before
# continuing.
#
if [ -f /tmp/computer.lock ]
then
while [ -f /tmp/computer.lock ]
do
sleep 60
done
fi
touch /tmp/computer.lock
#
# Copyright (C) The Santa Cruz Operation, 1985, 1986.
# This Module contains Proprietary Information of
# The Santa Cruz Operation, Microsoft Corporation
# and AT&T, and should be treated as Confidential.
#
#! computer_pr
# Options: lp -ob no banner
#
. [rest of the standard model here]
.
.
# send the file(s) to the standard out $copies times
while [ "$copies" -gt 0 ]
do
for file
do
echo -n " 0 6 F66" # Oki 32x codes
cat "$file" 2>&1
echo "\f\c"
echo -n " 0 6 F66" # Oki 32x codes
done
copies=`expr $copies - 1`
done
rm /tmp/computer.lock
stty -hupcl 0<&1
exit 0
The only drawback with this approach that I have encountered is when you
cancel a print job the lock is not removed. You have to remember to "rm
/tmp/computer.lock" after your cancel, otherwise you next jobs will never
print.
I remember trying to solve this once by trapping the rm lock sequence
inside the model, but it didn't work. I would be interested in finding a
better solution than this which doesn't force the user to remember to
remove a dead lock file.
Good luck.
--
Bill Irwin - TWG The Westrheim Group - Vancouver, BC, Canada
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
uunet!van-bc!twg!bill (604) 431-9600 (voice) | UNIX Systems
Bill.Irwin@twg.bc.ca (604) 431-4629 (fax) | Integration
-----------------------------
From: Eduardo Krell <ekrell@ulysses.att.com>
Subject: Re: ksh discriminates background processes
Keywords: ksh, nice, errr... ugly
Date: 2 Jun 90 13:51:16 GMT
Sender: netnews@ulysses.att.com
To: unix-wizards@sem.brl.mil
In article <siebren.644249314@piring.cwi.nl> siebren@cwi.nl (Siebren van der Zee) writes:
>Does anybody know why the new Korn shell lowers the priority
>of background processes?
Because you have the "bgnice" option on. Type "set -o" and you'll see
a line that says
bgnice off
This is the default behavior. If you want this changed, add
"set +o bgnice" to your ENV file.
Eduardo Krell AT&T Bell Laboratories, Murray Hill, NJ
UUCP: {att,decvax,ucbvax}!ulysses!ekrell Internet: ekrell@ulysses.att.com
-----------------------------
From: "Jay A. Konigsberg" <jak@sactoh0.uucp>
Subject: Re: SEX! or, how do I mail to a lot of unix users?
Date: 2 Jun 90 07:58:42 GMT
To: unix-wizards@sem.brl.mil
In article <900531083151.30e0b91a@Csa2.LBL.Gov> thermal%solgel.hepnet@CSA2.LBL.GOV writes:
>I would like to be able to send a mail message to all the users on
>a unix machine. Of course, I could do it the long way, that is,
>do a 'finger' or 'who', thus getting a list of all the users, and
>then sending a mail message to each, one at a time. Is there a
>quicker way? (it seems to me there could be two or three different
>ways, such as setting up a mailing list, or some nifty command that
>will do this on one stroke of the finger). Obviously, I'm not a
>unix guru or wizard, so make your explanation understandable, please.
>
>Thanks, Dana
Write a shell script named "mall" (mail all - but I love the name).
It scans the /etc/passwd file and extracts those login names with
UID >= 100. You can also have an optional filename with the login
names you want the message sent to.
One note: doing this will probably mean that some of the mail will
sit unread in /usr/mail (or /usr/spool/mail), so be careful how you
write it. Accuctally, someone out there might have already written
it.
-----------------------------
From: Eduardo Krell <ekrell@ulysses.att.com>
Subject: Re: ksh discriminates background processes
Keywords: ksh, nice, errr... ugly
Date: 2 Jun 90 16:49:52 GMT
Sender: netnews@ulysses.att.com
To: unix-wizards@sem.brl.mil
In article <13051@ulysses.att.com> I said:
>bgnice off
>
>This is the default behavior.
Oops. The default bgnice behavior is "on". I copied the above from my
shell output where I turn it off.
Eduardo Krell AT&T Bell Laboratories, Murray Hill, NJ
UUCP: {att,decvax,ucbvax}!ulysses!ekrell Internet: ekrell@ulysses.att.com
-----------------------------
From: Marc Wiz <wizm@mbf.uucp>
Subject: Init S on System V 3.2
Keywords: init single user mode
Date: 1 Jun 90 22:25:07 GMT
To: unix-wizards@sem.brl.mil
I and another engineer here are in need of some net wisdom.
Here's the problem:
on system V 3.2 performing an init S puts the system into single
user mode. It also makes the terminal that executed the init S
the system console. Also according to the man page init(1M), all
mounted file systems are left mounted and only processes spawned
by init are killed. What the man page and documentation does not
say is that any processes i.e. daemons that were created via
script files in /etc/rc* are still running. Which means that if
you perform an init 2 from this state then there will be two
copies of every daemon running. Obviously this is not a desire-
able state! :-)
The easy thing to do is just perform an init 6 which will reboot
the system. In the interests of getting the system back up to
multi-user mode in the shortest time, the ideal would be the init
2. What can we do to go back to run state 2 without rebooting?
And is this a bug or a feature?
Thanks in advance for the help. Marc
--
: Marc Wiz :
: Yes, that really is my last name. MAI Basic Four, Inc. :
: Tustin, CA 92680 :
: UUCP:sun!sequent!mbf!wizm Ma Bell:1-714-730-2602 :
: uunet!ccicpg!mbf!wizm :
-----------------------------
From: Quan Tang <qt@beach.cis.ufl.edu>
Subject: need help with 'curses'
Date: 2 Jun 90 18:45:25 GMT
Sender: news@bikini.cis.ufl.edu
To: unix-wizards@sem.brl.mil
I am going to use 'curses', but I have no references except man pages,
I will appreciate it very much if any unix expert send me some information about
it including your experience.
-----------------------------
From: carl brandauer <cbrandau@nyx.uucp>
Subject: Re: ksh discriminates background processes
Keywords: ksh, nice, errr... ugly
Date: 2 Jun 90 19:40:39 GMT
To: unix-wizards@sem.brl.mil
every shell i have used in the last 13 years has lowered the priority of
background processes - makes sense to me
-----------------------------
From: Martin Weitzel <martin@mwtech.uucp>
Subject: Lex man page flame (was Re: Lex and initial start conditions)
Date: 2 Jun 90 13:11:14 GMT
Posted: Sat Jun 2 14:11:14 1990
To: unix-wizards@sem.brl.mil
In article <116@bohra.cpg.oz> ejp@bohra.cpg.oz.au (Esmond Pitt) writes:
>In article <1990May30.174745.1161@csrd.uiuc.edu> pommu@iis.ethz.ch (Claude Pommerell) writes:
>>
[about changing start conditions at entry to yylex()]
>
>There are two even simpler ways.
`Simpler' mostly depends on your view and expectations ...
>
>Instead of effectively changing the initial condition to <Text>, either:
>
>1. Ensure each start-state is equipped with enough rules to handle any
>possible input, and, as the documentation does state, place all the
>unlabelled rules after all the labelled rules, and/or
Sounds not simpler to me.
>
>2. Label all the rules you only want applied in the INITAL state with
><INITIAL>, so they won't be applied as defaults in other states.
This trades off one undocumented feature (stuff *after* the first '%%'
line and *before* the first rule) against another undocumented feature.
But to be fair: Strictly following some man pages for lex nearly
every a nontrivial lex applications would use some undocumented
feautures.
I just looked up for the purpose of writing this:
1.) SVID (1986)
2.) XPG3 (1989)
3.) ISC Programmers Reference Manual
4.) ISC Programmers Guide (1988)
.FLAME ON
Not any single mentioning of start conditions in (4) at all (neither
the syntax in rules, nor the special action BEGIN).
Worse in some example the the advice is for a lex program to
#define BEGIN 1
(believe it or not) as a `good programming style' for returning
tokens. This finally reveals that the author can have never heard
something about start conditions. The example of the lex program
has a line:
begin return (BEGIN);
Please ISC, could you send the person who has written this guide
to a lex+yacc course (BTW: I'm teaching some :-)) before a revised
version is produced. Well, there is mentioned that yacc contains
a feature to supply token-defines, but it's bad practice to give
advices that turn out to be not only unnecessary, but dangerous
too. The only advice in this guide that isn't near to worthless
is to look into the paper about Lex written by Mike Lesk. (You were
better advised printing this paper in the guide than the section
that's in by now.)
An other advice there is to check out the reference manual (3).
Be aware: IF YOU TRY TO USE LEX WITH THIS REFERENCE, YOU WILL
BE ABSOLUTELY LOST. (Better save your time trying,
rather end work soon, go out and have a nice evening
- or, again, look for the Lesk-paper.)
Ehhm, we are talking about start conditions. The reference manual
is *very* silent about them - in fact no mentioning. On the
other hand: The author was quite careful to mention, that the
"-r option is not yet fully operational". (What this option
tells is that lex should produce RATFOR source instead of C.
Oh, how many times I needed that an wondered why it just
didn't "fully" work - but good news, not "yet", that is, the
day will come when I finally can switch from C to RATFOR :-).)
But before we beat ISC too much: I suppose they took what they
got from somewhere (AT&T?) and only made it a little worse.
Let's look at (1) - and don't say a reference dated from 1986 is
too old today: The stuff we are talking about is *much* longer
in lex. SVID does the good job of printing a table which
shows the regular expression syntax for lex rules (it's quite
similar as the "extended regular expressions" of egrep and
awk, but there are some differences). In this table you'll
find the syntax of start conditions, but not the least
mentioning of them and BEGIN in the rest of the text. So, if
you read the table you probably think you must be stupid, if
you don't know lex and hence you don't understand what
<s>r the occurence of the regular expression
r only when the program is in start
condition (state) s
shall tell you. (Again, start conditions or states and the
special action BEGIN is not mentioned anywhere else in the
section).
Finally to (2), which seems a not so bad re-work of the SVID in
other areas. A quick scan thru the lex section reveals that it is
quite similar to (1), but the table with the regular expression
syntax is ommitted in favor of a difference list to extended regular
expressions. (BTW: The difference list is not complete.) The same
sentence concerning the <s>r-Syntax as in (1) appears but again
nothing about start conditions, states, and BEGIN in the rest of
the section.
.FLAME OFF
Hello AT&T, anybody listening: If you haven't revised the manuals
recently, please do a complete rewrite of the lex section but find
somebody as author who has sufficient experience with lex+yacc in
non-trivial applications *and* who can explain understandable to
mortals. (From many publications I know such people are working
at AT&T - I'm volunteering doing a proof-read.)
>
>Placing non-labelled rules before labelled rules is probably the single
>most common error in writing LEX scripts, even after 15 years.
>
>I don't know why.
After reading the above, you probably know why many novices struggle
with lex. Concerning your the problem, here are the
THREE BIG DISAMBIGUATING RULES
1) leftmost
2) longer
3) first in source
which tells us: Take the input stream and write it down in one line
from left to right: Then, in case two rules might match some part of
the input stream, lex chooses the rule that matches more to the left,
that matches the longer regular expression or that matches the regular
expression which appears first in (lex) source, with (1) having higher
priority than (2) having higher priority than (3).
This is well choosen, because it enables us to do the following:
"if" { ... action for keyword if ... }
[a-z]+ { ... action for identifier ... }
which triggers the second for " fif " (because of 1), as well
as for " iff " (because of 2), but the first for " if " (because
of 3). Start conditions are no exceptions from this rule!
--
Martin Weitzel, email: martin@mwtech.UUCP, voice: 49-(0)6151-6 56 83
-----------------------------
From: Scott Weikart <weikart@arisia.xerox.com>
Subject: can Sys. V Rel. 3.2 support > 16MB RAM when can only DMA to <= 16MB?
Date: 3 Jun 90 00:56:39 GMT
To: unix-wizards@sem.brl.mil
First, some details for those of you who are interested in IBM PC/AT
compatible, Intel 80386-based computers. I'm trying to use more than 16MB of
main memory on an AT/386 running Interactive 386/ix 2.0.2 (V.3.2). I'm using
the latet Chantal SCSI driver with the Adaptec AHA1542 SCSI host adapter. The
AHA1542 has an on-board DMA for doing data transfers; since it uses the AT
bus, it only works with 24 bits of address, i.e. it can access at most 16MB of
memory. But I'd like to buy a motherboard that will hold 32MB of memory,
because I'm starting to thrash.
So, my machine would have more than 16MB of memory, but the DMA on my disk
controller will access at most 16MB of memory. How can I make this work?
I have two ideas on how to do this. One is to only use block devices on the
local machine (so that all disk DMA is done to the disk cache, which is always
in low memory), and put raw devices on remote machines accessible via RFS over
ethernet. Although tty devices are raw, they always do their transfers to
kernel buffers as near as I can figure. I'd put my tape devices on remote
machines. The tricky part is the swap device; although it's a block device,
it does transfers directly into user space without going through the disk
cache [acording to Bach]. To get a swap device, I'd remote mount a disk
partition from another machine using RFS: I would boot the machine with a
local swap region, then start up RFS, then mount an unused partition from a
remote machine, then use /etc/swap to setup the remote partition as a swap
device, then use /etc/swap to delete the partitin on the local machine. Note
that I'm not too worried about performance loss from swapping/paging across
ethernet, because I'll be reducing swap/page activity drastically by doubling
the amount of RAM available. But can V.3.2 handle a swap partition on a
remote machine?
The second idea is to use a feature that's (maybe) specific to V/386. There's
a file /etc/default/boot that contains boot time parameters (described by
boot(1)). The MEMRANGE parameter lets you specify a number of different
ranges of physical address space where RAM can found; for each range of
address space, you can specify whether or not DMA accesses work to this range.
If I specify not to use DMA for memory above 16MB, will all my problems be
magically solved? If so, how is it done? For example, Bach says that when
swapping a process the whole process is stored in contiguous sectors of the
swap device; will the kernel grab some blocks from the disk cache and do the
swapping in chunks, using the disk cache blocks as the DMA-accessible
intermediary? And will the kernel do all the chunking with disk cache blocks
transparently to the disk driver, or will the driver have to get the MEMRANGE
parameters and do its own special tricks for transferring into memory where
DMA can't work?
Any other ideas on how to handle this problem?
Please send me comments in email, since I din't normally read these
newsgroups. I'll post any feedback I receive.
--
Scott Weikart
Community Data Processing (415)322-9069
weikart@arisia.xerox.com pyramid!cdp!scott
-----------------------------
From: Scott Weikart <weikart@arisia.xerox.com>
Subject: Re: can Sys. V Rel. 3.2 support > 16MB RAM when can only DMA to <= 16MB?
Date: 3 Jun 90 02:46:41 GMT
To: unix-wizards@sem.brl.mil
In article <9628@arisia.Xerox.COM>, weikart@arisia.Xerox.COM (Scott Weikart) writes:
>
> But can V.3.2 handle a swap partition on a
> remote machine?
I just read the "386/ix Network Connections Facilities Release Notes - Release
2.0". The next to last item in the list of bugs is "Swap devices cannot be
remote...". So much for that idea. How about my other idea: will the kernel
support the MEMRANGE no-DMA parameter in /etc/default/boot without any
assistance from the disk driver?
--
Scott Weikart
Community Data Processing (415)322-9069
weikart@arisia.xerox.com pyramid!cdp!scott
-----------------------------
From: Ronald Pikkert <ronald@atcmp.nl>
Subject: Re: Removing garbage files
Date: 2 Jun 90 21:00:53 GMT
To: unix-wizards@sem.brl.mil
From article <156@TWG.UUCP>, by bill@TWG.UUCP (Bill Irwin):
> Here is one that has got me beat, frustrated and down right angry. I
> have some files in a directory that I can't remove.
Your shell probably strips the high order bit which causes rm to be unable
to delete these files.
You can remove them using a c-program. I wrote a shell script that creates
a c-program that does the job:
------------------- cut here ------------------
echo "main() {"
ls -b | sed 's/\(\\\)\([^0]\)/\10\2/g
s/\\$/\\\\/
s/"/\\"/g
s/^/unlink(\"/
s/$/");/
'
echo "}"
------------------- cut here ------------------
Run this script in the directory and it will generate a program
dl.c Compile the program (cc dl.c -o dl). The run ./dl and there
will be no need to reformat your anymore disk :-)
-
Ronald Pikkert E-mail: ronald@atcmp.nl
@ AT Computing b.v. Tel: 080 - 566880
Toernooiveld
6525 ED Nijmegen
-----------------------------
From: George Bron Faison <Bron@cup.portal.com>
Subject: time dep login
Date: 3 Jun 90 04:36:09 GMT
To: unix-wizards@sem.brl.mil
9A couple of ideas you might puruse...
Placing a program in passwd in place of /bin/sh
to check the time and display a nice message (vs. just
failing as some of the other suggestions imply)
if your user is out of his time limits; or to invoke
a login sh if he/she is within time bounds, etc.
If you have more than one user to monitor, maybe something
invoked by /etc/profile?
If your user is "tied" to s specific port, an alternate
getty with the appropriate code might suffice?
(Or use inittab to "close" that port?)
If YOU control the ".profile" for your users, you
could do it there also (you can also handle this by having
user log into a common directory for processing before
being switched to their HOME directories).
I'm sure there are lots of other ways, too.
George "Bron" Faison
Modern Office Systems Technology, Inc.
(804) 730-1467 or Bron@cup.portal.com or
6006-B Mechanicsville 'Pike, Mech. VA. 23111
-----------------------------
End of UNIX-WIZARDS Digest
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----Transcript of message follows----
Date: 11 Aug 90 06:45:00 EST
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#113
To: "ise.ncsl.nist.gov" <ise.ncsl.nist.gov@ecf.ncsl.nist.gov>
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Date: Sat, 11 Aug 90 05:45:11 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#113
Message-ID: <9008110545.aa03234@SEM.BRL.MIL>
UNIX-WIZARDS Digest Sat, 11 Aug 1990 V10#113
Today's Topics:
Re: Cron - First Saturday of the month
Re: Streams message allocation
nested loops
Re: nested loops
waitpid() ???
unix sys v - uptime question
Interesting keyboard read problem (ioctl, function keys)
sockets and signals (in C)
Re: sockets and signals (in C)
Re: Re.: UNdeleting files
seeking information about file system details.
evaluating ${10} and above in sh/ksh
Re: How variables can be specified as arguments
Re: ln -f
-----------------------------------------------------------------
From: Bob Strait <rls@svcs1.uucp>
Subject: Re: Cron - First Saturday of the month
Date: 9 Aug 90 17:13:32 GMT
To: unix-wizards@sem.brl.mil
In article <19744@orstcs.CS.ORST.EDU> curt@oce.orst.edu (Curt Vandetta) writes:
> I'm wondering if anyone has a way of making cron run a job on the
> first Saturday of every month?
>
How about running your job each of the first seven days of every
month, and have the job first test whether it's Saturday and
exit if it's not. There are several easy ways to do the test:
'date | grep Sat' comes to mind.
--
BUBBA (aka Bob Strait) ...!mips!svcs1!rls
Silicon Valley Computer Society
Sunnyvale, CA
--
-----------------------------
From: Bob McGowen x4312 dept208 <bob@wyse.wyse.com>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 02:40:29 GMT
Sender: news@wyse.wyse.com
To: unix-wizards@sem.brl.mil
In article <1990Aug8.185745.16606@iwarp.intel.com> merlyn@iwarp.intel.com (Randal Schwartz) writes:
>In article <19744@orstcs.CS.ORST.EDU>, curt@oce (Curt Vandetta) writes:
>| I'm wondering if anyone has a way of making cron run a job on the
>| first Saturday of every month?
>
>3 4 1-7 * 6 command
>
>to make 'command' run at 4:03am... adjust the first two fields as
>necessary. Remember, the parameters are "and"-ed together.
...flame deleted
My documentation states that a line like the one you have provided
would cause the command to run on EVERY Saturday as well as on each
of the first seven days in the month.
My flame--
I would be very interested if you could provide a cron only method
of getting my cron to execute on the first Saturday (or any other
day) such that it executes on that single day only. My attempts at
solving this have been to combine cron to run the command on Saturday
and have command be a script that checks the date to be sure it is
less than or equal to 7. But this only works for the first 13 days
so I have to figure out the next exclusion, probably to limit between
a start and stop. In any case, getting cron to do what Curt wants is
a little more difficult. Possibly (probably, I think) even wizard
caliber.
Bob McGowan (standard disclaimer, these are my own ...)
Product Support, Wyse Technology, San Jose, CA
..!uunet!wyse!bob
bob@wyse.com
-----------------------------
From: Michael van Elst <p554mve@mpirbn.mpifr-bonn.mpg.de>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 14:28:35 GMT
Posted: Fri Aug 10 15:28:35 1990
To: unix-wizards@sem.brl.mil
In article <1990Aug8.185745.16606@iwarp.intel.com> merlyn@iwarp.intel.com (Randal Schwartz) writes:
>In article <19744@orstcs.CS.ORST.EDU>, curt@oce (Curt Vandetta) writes:
>| I'm wondering if anyone has a way of making cron run a job on the
>| first Saturday of every month?
>3 4 1-7 * 6 command
>to make 'command' run at 4:03am... adjust the first two fields as
>necessary. Remember, the parameters are "and"-ed together.
From the SunOS4.03 Manual:
Note: the specification of days may be made by two fields
(day of the month and day of the week). If both are specified
as a list of elements, both are adhered to. For example:
0 0 1,15 * 1 command
would run a command on the first and the fifteenth of each month,
as well as on every Monday.
.
.
Seems that, at least here, your suggestion doesn't work.
--
Michael van Elst
UUCP: universe!local-cluster!milky-way!sol!earth!uunet!unido!mpirbn!p554mve
Internet: p554mve@mpirbn.mpifr-bonn.mpg.de
"A potential Snark may lurk in every tree."
-----------------------------
From: Ed Anselmo <anselmo-ed@cs.yale.edu>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 16:42:38 GMT
Sender: news@cs.yale.edu
Nntp-Posting-Host: bigbird.cf.cs.yale.edu
To: unix-wizards@sem.brl.mil
I peeked at the sources -- the BSD cron "ands" all the fields
together.
I don't have Sun 4.x sources, but under SunOS 4.0.3, I saw
the same behavior as David Canzi saw.
So, with a crontab like:
28 12 1-5 * 5 anselmo date > /homes/facility/anselmo/temp/www
28 12 7-11 * 1 anselmo date > /homes/facility/anselmo/temp/xxx
28 12 1-5 * 1 anselmo date > /homes/facility/anselmo/temp/yyy
28 12 7-11 * 5 anselmo date > /homes/facility/anselmo/temp/zzz
running on Fri Aug 10, under the BSD cron, only zzz got created.
Running under Sun 4.x cron (with the crontab entries suitably
modified), www, xxx, and zzz got created.
--
Ed Anselmo anselmo-ed@cs.yale.edu {harvard,cmcl2}!yale!anselmo-ed
-----------------------------
From: Maarten Litmaath <maart@cs.vu.nl>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 17:26:39 GMT
Sender: news@cs.vu.nl
To: unix-wizards@sem.brl.mil
The manual (man 5 crontab on SunOS 4.0.3c):
[...]
Note: the specification of days may be made by two fields
(day of the month and day of the week). If both are speci-
fied as a list of elements, both are adhered to. For exam-
ple,
0 0 1,15 * 1
would run a command on the first and fifteenth of each
month, as well as on every Monday. To specify days by only
one field, the other field should be set to *. For example,
0 0 * * 1
would run a command only on Mondays.
[...]
The code:
int
match(cp, loct)
register char **cp;
register struct tm *loct;
{
int cancel_ex = 0;
*cp = cmp(*cp, loct->tm_min, &cancel_ex);
*cp = cmp(*cp, loct->tm_hour, &cancel_ex);
*cp = cmp(*cp, loct->tm_mday, &cancel_ex);
*cp = cmp(*cp, loct->tm_mon, &cancel_ex);
*cp = cmp(*cp, loct->tm_wday, &cancel_ex);
return(!cancel_ex);
}
char *
cmp(p, v, cancel_ex)
char *p;
int *cancel_ex;
{
register char *cp;
cp = p;
switch(*cp++) {
case EXACT:
if (*cp++ != v)
(*cancel_ex)++;
return(cp);
case ANY:
return(cp);
case LIST:
while(*cp != LIST)
if(*cp++ == v) {
while(*cp++ != LIST)
;
return(cp);
}
(*cancel_ex)++;
return(cp+1);
case RANGE:
if(cp[0] < cp[1]) {
if(!(cp[0]<=v && cp[1]>=v))
(*cancel_ex)++;
} else if(!(v>=cp[0] || v<=cp[1]))
(*cancel_ex)++;
return(cp+2);
}
if(cp[-1] != v)
(*cancel_ex)++;
return(cp);
}
The conclusion: the manual and the code contradict each other!
The example
0 0 1,15 * 1
...will run the job on each monday whose date is either the 1st or the 15th!
It might be too late to fix the manual... (Grrrr!)
--
"UNIX was never designed to keep people from doing stupid things, because
that policy would also keep them from doing clever things." (Doug Gwyn)
-----------------------------
From: Chip Salzenberg <chip@tct.uucp>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 17:46:26 GMT
To: unix-wizards@sem.brl.mil
According to dmcanzi@watserv1.waterloo.edu (David Canzi):
>if [ `date | sed 's/^... ... *\([^ ]*\) .*/\1/'` -le 7 ]
At least on SysV, this is working too hard! Use this instead:
if [ "`date +%d`" -le 7 ]
Manual pages are wonderful things...
--
Chip Salzenberg at ComDev/TCT <chip@tct.uucp>, <uunet!ateng!tct!chip>
-----------------------------
From: Maarten Litmaath <maart@cs.vu.nl>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 18:13:28 GMT
6@star.cs.vu
Sender: news@cs.vu.nl
To: unix-wizards@sem.brl.mil
In article <7286@star.cs.vu.nl>, I wrote:
)The manual (man 5 crontab on SunOS 4.0.3c):
)...
)The code:
)...
I forgot to mention the code is _not_ SunOS 4.0.3c (still no up to date
sources...)
Anyway, my point still stands: _anding_ the fields is preferred (as Randal
already explained), but it might be too late to fix the specifications...
--
"UNIX was never designed to keep people from doing stupid things, because
that policy would also keep them from doing clever things." (Doug Gwyn)
-----------------------------
From: Ronald S H Khoo <ronald@robobar.co.uk>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 19:05:17 GMT
To: unix-wizards@sem.brl.mil
In article <1990Aug10.063819.5253@iwarp.intel.com> merlyn@iwarp.intel.com (Randal Schwartz) writes:
> Sigh. Sorry. I'll crawl under my rock now. Cron's only for the
> heavyweights, anyway.
System V cron isn't just for heavyweights, though, it's got per-user
crontabs, remember, so joe-random-non-wizard who has his own crontab
has to understand the manpage. Sigh.
Someone once mentioned wanting to write a System V-like cron in perl
so he could have per-user crontabs on his machine. I wonder who
it was, and how he parsed the manpage ?
--
Eunet: Ronald.Khoo@robobar.Co.Uk Phone: +44 81 991 1142 Fax: +44 81 998 8343
Paper: Robobar Ltd. 22 Wadsworth Road, Perivale, Middx., UB6 7JD ENGLAND.
-----------------------------
From: Randal Schwartz <merlyn@iwarp.intel.com>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 22:43:31 GMT
6@star.cs.vu
Sender: news@iwarp.intel.com
To: unix-wizards@sem.brl.mil
In article <7286@star.cs.vu.nl>, maart@cs (Maarten Litmaath) writes:
| The code:
[deleted to protect my eyes, but it *is* the code I remember ...]
| The conclusion: the manual and the code contradict each other!
| The example
|
| 0 0 1,15 * 1
|
| ...will run the job on each monday whose date is either the 1st or the 15th!
| It might be too late to fix the manual... (Grrrr!)
Yes, this is my point. Actually, what I think happened is that you
posted the V7-derived cron, and Sunos4.1 went to the user-crontab
System (blech) V cron, and I suspect that they put some widgets in
there to do this stupid "OR" logic that I complained about in my last
two postings.
Anyone with access to system V source care to comment? Are there some
yucky kludges in there?
Just another System V disliker,
--
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/
-----------------------------
From: David Canzi <dmcanzi@watserv1.waterloo.edu>
Subject: Re: Cron - First Saturday of the month
Date: 11 Aug 90 03:08:18 GMT
To: unix-wizards@sem.brl.mil
In article <1990Aug8.214539.1264@watserv1.waterloo.edu> I wrote:
>In a sh script, it can be done by:
>
>if [ `date | sed 's/^... ... *\([^ ]*\) .*/\1/'` -le 7 ]; then
> ...
>fi
This is better done using awk:
if [ `date | awk '{print $3}'` -le 7 ]; then
...
fi
--
David Canzi
-----------------------------
From: Larry McVoy <lm@snafu.sun.com>
Subject: Re: Streams message allocation
Keywords: streams deadlock
Date: 9 Aug 90 17:21:06 GMT
Sender: news@sun.eng.sun.com
To: unix-wizards@sem.brl.mil
In article <1990Aug2.043059.578@cbnewsl.att.com> sar0@cbnewsl.att.com (stephen.a.rago) writes:
>The number of messages needed per buffer class (size) is something that
>can only be determined statistically or empirically. In the absence of
>information like inter-arrival rate of allocation requests and message
>hold times, the best way to proceed is to start with an educated guess
>of how many messages you may need.
Here's a package I wrote a few years ago when tuning STREAMS for SCO XENIX
(I was porting the LAI TCP/IP to XENIX and tuning was really critical).
Use this while your system is under a "normal" load and it will give you a
pretty good idea of where to set things. No promises that it works -
it worked on SCO XENIX a while ago, beyond that you're on your own. If
you have SCO XENIX & TCP/IP you should have this program already.
# This is a shell archive. Remove anything before this line, then
# unpack it by saving it in a file and typing "sh file". (Files
# unpacked will be owned by you and have default permissions.)
#
# This archive contains:
# Makefile mode.c sw.1 sw.c term.h termcap.c
echo x - Makefile
cat > "Makefile" << '//E*O*F Makefile//'
O = sw.o termcap.o mode.o
S = Makefile sw.1 sw.c termcap.c mode.c term.h
#CFLAGS=-DUNIX=\"/xenix\" -DKMEM=\"/dev/mem\" -DSAVECNT=0
BIN=/usr/local/bin
all sw: $O
cc $O -ltermlib -o sw
install: sw
cp sw $(BIN)
chown root $(BIN)/sw
chmod 4755 $(BIN)/sw
clean:
rm -f $O a.out core shar
clobber: clean
rm -f sw
shar:
shar $S > shar
//E*O*F Makefile//
echo x - mode.c
cat > "mode.c" << '//E*O*F mode.c//'
/*
* copyright (C) 1986 by Larry McVoy
* MUST be distributed in source form only.
*/
# include <stdio.h>
# include <sgtty.h>
# include <fcntl.h>
static struct sgttyb buf;
static done = 0;
delay(on)
{
if (on) {
int flags;
fcntl(0, F_GETFL, &flags);
flags &= ~O_NDELAY;
return fcntl(0, F_SETFL, flags);
}
else {
return fcntl(0, F_SETFL, O_NDELAY);
}
}
cbreak(on)
{
if (!done) {
ioctl(fileno(stdin), TIOCGETP, &buf);
done++;
}
if (on) {
buf.sg_flags |= CBREAK;
ioctl(fileno(stdin), TIOCSETP, &buf);
}
else {
buf.sg_flags &= ~CBREAK;
ioctl(fileno(stdin), TIOCSETP, &buf);
}
}
echo(on)
{
if (!done) {
ioctl(fileno(stdin), TIOCGETP, &buf);
done++;
}
if (on) {
buf.sg_flags |= ECHO;
ioctl(fileno(stdin), TIOCSETP, &buf);
}
else {
buf.sg_flags &= ~ECHO;
ioctl(fileno(stdin), TIOCSETP, &buf);
}
}
//E*O*F mode.c//
echo x - sw.1
cat > "sw.1" << '//E*O*F sw.1//'
.TH SW 1
.UC 4
.SH NAME
sw - (stream watch) watch streams resources on System V
.SH SYNOPSIS
.B sw
.SH DESCRIPTION
.I Sw
digs into kmem to find out how many streams, queues, message blocks, and data
blocks are in use. It find this in the \fIstruct strstat strst\fR variable.
For each category mentioned above the following fields are printed:
.IP Use
(strst.use)
How many of the resource in question are in use.
.IP "Ave10, Ave30, Ave60, Ave120"
As above, only the value is averaged over the last N iterations
(an iteration is
about one second).
.IP Total
(strst.total)
The total number of the resource used since boot time or the last time it
was cleared.
.IP Max
(strst.max)
The maximum number of the resource allocated at the same time.
.IP Fail
(strst.fail)
The number of times a request was made, for the resource, that could not
be granted.
.PP
The data block section is further broken down into sub classes. This section
has a slightly different format; in the title section the field is
\fISiz<#> Count <#>\fR, where the first number is the data block size and
the second number is the number of data blocks statically allocated.
.PP
The screen is managed by curses. It will respond to:
.IP c
clear the total max & fail fields (you have to have write permission on
/dev/mem).
.IP ^L
redraw the screen.
.IP N
Where N is 0-9. Set the number of seconds between interations.
.IP q
(quit) Quit the program.
.IP ^L
(Control-L) Refresh the screen.
.SH FILES
.DT
/dev/kmem kernel memory
.br
/unix for getting variable addresses
.SH BUGS
The definitions of the various fields is my best guess, they do not reflect
any AT&T documentation that I've read.
.SH COPYRIGHT
\fBSw\fR is copyright 1988 by Larry McVoy. Permission is hereby granted to
publish strings in source or object form as long as all copyright notices
are retained. Object-only distributions are permitted only if the source
is also freely available from the distributer. Any fee charged for such
publication may consist only of a reasonable charge for any media used.
.SH AUTHOR
Larry McVoy (lm@eng.sun.com)
//E*O*F sw.1//
echo x - sw.c
cat > "sw.c" << '//E*O*F sw.c//'
/*
* copyright 1988 by Larry McVoy. All rights reserved.
* If you redistribute this you must distribute in source form.
*/
#include "term.h"
#include <signal.h>
#ifdef M_XENIX
#include <a.out.h>
#else
#include <nlist.h>
#endif
#include <ctype.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stream.h>
#include <sys/stropts.h>
#include <sys/strstat.h>
#include <sys/var.h>
#if defined(M_XENIX) || defined(sys5)
#include <sys/utsname.h>
#endif
#ifndef UNIX
#define UNIX "/vmunix"
#endif
#ifndef KMEM
#define KMEM "/dev/kmem"
#endif
#ifdef M_XENIX
#define v_nblk4096 v_nblk8192
#endif
#ifdef sun
#define NCLASS 9
#endif
#ifndef SAVECNT
#define SAVECNT 121
#endif
#define kbytes(x) ( ((x)+1023) >> 10)
#ifdef M_XENIX
#define nlist xlist
#define n_value xl_value
#define n_name xl_name
struct nlist nl[] = {
#define NL_STRST 0
{0,0,0,"_strst"},
#define NL_RBSIZE 1
{0,0,0,"_rbsize"},
#define NL_V 2
{0,0,0,"_v"},
#define NL_DBALLOC 3
{0,0,0,"_dballoc"},
#define NL_NMBLOCK 4
{0,0,0,"_nmblock"},
{0,0,0,(char *) 0},
};
#else
#ifdef sys5
struct nlist nl[] = {
#define NL_STRST 0
{"_strst"},
#define NL_RBSIZE 1
{"_rbsize"},
#define NL_V 2
{"_v"},
#define NL_DBALLOC 3
{"_dballoc"},
#define NL_NMBLOCK 4
{"_nmblock"},
{ 0 },
};
#else
#ifdef sun
char* nl_names[] = {
#define NL_STRST 0
"_strst",
#define NL_RBSIZE 1
"_rbsize",
#define NL_NDBLKS 2
"_ndblks",
#define NL_DBALLOC 3
"_dballoc",
#define NL_NMBLOCK 4
"_nmblock",
"",
};
struct nlist nl[sizeof(nl_names)/sizeof(char*)];
#endif /* sun */
#endif /* sys5 */
#endif /* M_XENIX */
ushort rbsize[NCLASS];
short cnt[NCLASS];
struct dbalcst dballoc[NCLASS];
int total, ndblock, nmblock, fd, sleeptime = 1;
#ifndef sun
struct var v;
#endif
typedef struct {
alcdat stream;
alcdat queue;
alcdat mblock;
alcdat dblock;
alcdat dblk[NCLASS];
} Strstat;
Strstat strst;
/*
* It's the main thing...
*/
main(ac, av)
char** av;
{
int* p;
int i;
int done();
for (i=1; i<ac; ++i) {
if (av[i][0] == '-')
if (isdigit(av[i][1]))
sleeptime = atoi(&av[i][1]);
}
/*
* get stuff from kmem
*/
# ifdef sun
for (i=0; i<sizeof(nl_names)/sizeof(char*); ++i)
nl[i].n_name = nl_names[i];
# endif
if (nlist(UNIX, nl))
error("nlist");
if (((fd = open(KMEM, 2)) == -1) && ((fd = open(KMEM, 0)) == -1))
error(KMEM);
readstuff();
# ifdef sun
for (i=0; i<NCLASS; ndblock += cnt[i++])
;
# else
for (i=0, p= &v.v_nblk4096; i<NCLASS; ndblock += (cnt[NCLASS - ++i] = *p++))
;
# endif
/*
* screen/mode stuff
*/
termcap();;
echo(0);
cbreak(1);
delay(0);
signal(SIGHUP, done);
signal(SIGINT, done);
signal(SIGQUIT, done);
signal(SIGTERM, done);
screen();
/*
* display until quit
*/
for ( ;; ) {
if (lseek(fd, nl[NL_STRST].n_value, 0) == -1)
error("lseek");
if (read(fd, &strst, sizeof(strst)) != sizeof(strst))
error("read");
dump(&strst);
for (i=0; i<sleeptime; ++i) {
if (input())
break;
sleep(1);
}
input();
}
}
/*
* look for commands; expect to be in cbreak mode
*/
input()
{
char c;
if (read(0, &c, 1) != 1)
return 0;
switch (c) {
case 'c':
clearstuff();
return 1;
case ' ':
screen();
return 1;
case 'q':
done();
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
sleeptime = c - '0';
Pause();
return 1;
case '?':
case 'h':
clear();
tprint("", 0, 0);
printf("\nOptions are\n");
printf("\tc\tclear total, max, and fail fields\n");
printf("\t^L\trefresh the screen\n");
printf("\tq\tquit\n");
printf("\tN\twhere N is a number 0..9 for the delay between refresh\n");
printf("Hit any key to continue....\n");
while (read(0, &c, 1) != 1)
sleep(1);
screen();
return 1;
default:
return 0;
}
}
/*
* clear the total, max, and fail fields
*
* N.B. assumes acldat is use, total, max, fail
* and there are NCLASS+4 acldat's in a strstat
*/
clearstuff()
{
static int clr[3];
register i;
clear();
lseek(fd, nl[NL_STRST].n_value+sizeof(int), 0);
for (i=0; i<NCLASS+4; ++i) {
if (write(fd, clr, sizeof(clr)) != sizeof(clr))
perror("write");
lseek(fd, sizeof(int), 1);
}
screen();
}
/*
* display the "once only" stuff
*/
screen()
{
char buf[200];
register i;
#if defined(M_XENIX) || defined(sys5)
struct utsname u;
#else
char host[100];
#endif
clear();
#if defined(M_XENIX) || defined(sys5)
uname(&u);
sprintf(buf, "Host=%s", u.nodename);
#else
gethostname(host, sizeof(host));
sprintf(buf, "Host=%s", host);
#endif
tprint(buf, 50, 0);
# if SAVECNT > 0
sprintf(buf, "%11s%5s%6s%6s%6s%6s%7s%8s%8s%8s",
"Resource", "Cnt", "Use", "Ave10", "Ave30", "Ave60", "Ave120", "Total",
"Max", "Fail");
# else
sprintf(buf, "%11s%5s%10s%8s%8s%8s",
"Resource", "Cnt", "Use", "Total", "Max", "Fail");
# endif
tprint(buf, 0, 2);
# ifdef sun
sprintf(buf, "%11s:%4s", "stream", "?");
tprint(buf, 0, 3);
sprintf(buf, "%11s:%4s", "queue", "?");
tprint(buf, 0, 4);
# else
sprintf(buf, "%11s:%4d", "stream", v.v_nstream);
tprint(buf, 0, 3);
sprintf(buf, "%11s:%4d", "queue", v.v_nqueue);
tprint(buf, 0, 4);
# endif
sprintf(buf, "%11s:%4d", "mblock", nmblock);
tprint(buf, 0, 5);
sprintf(buf, "%11s:%4d", "dblk totals", ndblock);
tprint(buf, 0, 6);
# if SAVECNT > 0
sprintf(buf, "%4s%4s%4s%4s%6s%6s%6s%6s%7s%8s%8s%8s",
"Size", "Cnt", "Med", "Low", "Use", "Ave10", "Ave30", "Ave60", "Ave120", "Total", "Max", "Fail");
# else
sprintf(buf, "%-4s%4s%4s%4s%4s%6s%8s%8s%8s",
"Mem", "Size", "Cnt", "Med", "Low", "Use", "Total", "Max", "Fail");
# endif
tprint(buf, 0, 8);
for (total=i=0; i<NCLASS; ++i) {
register lo = dballoc[i].dba_lo;
register med = dballoc[i].dba_med;
total += rbsize[i] * cnt[i];
# if SAVECNT > 0
sprintf(buf, "%4d %3d %3d %3d", rbsize[i], cnt[i], med, lo);
# else
sprintf(buf, "%3d %4d %3d %3d %3d", kbytes(rbsize[i] * cnt[i]),
rbsize[i], cnt[i], med, lo);
# endif
tprint(buf, 0, 9 + i);
}
sprintf(buf, "Buffers (used/total) = ");
tprint(buf, 0, 23);
Pause();
}
Pause()
{
char buf[40];
sprintf(buf, "Pause=%d", sleeptime);
tprint(buf, 0, 0);
}
# if SAVECNT == 0
/*
* display the information, called once per second (about)
*
* No averaging version
*/
dump(s)
register struct strstat* s;
{
char buf[80];
register i, mem = 0;
static calls = 0;
sprintf(buf, "%6d%8d%8d%8d",
s->stream.use, s->stream.total, s->stream.max, s->stream.fail);
tprint(buf, 20, 3);
sprintf(buf, "%6d%8d%8d%8d",
s->queue.use, s->queue.total, s->queue.max, s->queue.fail);
tprint(buf, 20, 4);
sprintf(buf, "%6d%8d%8d%8d",
s->mblock.use,
s->mblock.total, s->mblock.max, s->mblock.fail);
tprint(buf, 20, 5);
sprintf(buf, "%6d%8d%8d%8d",
s->dblock.use, s->dblock.total, s->dblock.max, s->dblock.fail);
tprint(buf, 20, 6);
for (i=0; i<NCLASS; ++i) {
mem += s->dblk[i].use * rbsize[i];
sprintf(buf, "%6d%8d%8d%8d",
s->dblk[i].use, s->dblk[i].total, s->dblk[i].max, s->dblk[i].fail);
tprint(buf, 20, 9 + i);
}
sprintf(buf, "%d/%d Kbytes", kbytes(mem), kbytes(total));
tprint(buf, 23, 23);
calls++;
sprintf(buf, "Calls=%d", calls);
tprint(buf, 10, 0);
}
# else
/*
* display the information, called once per second (about)
*
* Averaging version
*/
dump(s)
register struct strstat* s;
{
char buf[80];
register i, j, b10, b30, b60, b120, mem = 0;
static struct strstat pst[SAVECNT];
static struct strstat sum10, sum30, sum60, sum120;
static calls = 0;
j = calls % SAVECNT;
b10 = (j + SAVECNT - 10) % SAVECNT;
b30 = (j + SAVECNT - 30) % SAVECNT;
b60 = (j + SAVECNT - 60) % SAVECNT;
b120 = (j + SAVECNT - 120) % SAVECNT;
memcpy(&pst[j], s, sizeof(struct strstat));
addstrst(s, &sum10);
addstrst(s, &sum30);
addstrst(s, &sum60);
addstrst(s, &sum120);
if (!calls) {
mulstrst(&sum10, 10);
mulstrst(&sum30, 30);
mulstrst(&sum60, 60);
mulstrst(&sum120, 120);
for (i=1; i<SAVECNT; ++i)
memcpy(&pst[i], s, sizeof(struct strstat));
}
else {
substrst(&pst[b10], &sum10);
substrst(&pst[b30], &sum30);
substrst(&pst[b60], &sum60);
substrst(&pst[b120], &sum120);
}
sprintf(buf, "%6d%6d%6d%6d%7d%8d%8d%8d",
s->stream.use,
sum10.stream.use / 10, sum30.stream.use / 30, sum60.stream.use / 60,
sum120.stream.use / 120,
s->stream.total, s->stream.max, s->stream.fail);
tprint(buf, 16, 3);
sprintf(buf, "%6d%6d%6d%6d%7d%8d%8d%8d",
s->queue.use,
sum10.queue.use / 10, sum30.queue.use / 30, sum60.queue.use / 60,
sum120.queue.use / 120,
s->queue.total, s->queue.max, s->queue.fail);
tprint(buf, 16, 4);
sprintf(buf, "%6d%6d%6d%6d%7d%8d%8d%8d",
s->mblock.use,
sum10.mblock.use / 10, sum30.mblock.use / 30, sum60.mblock.use / 60,
sum120.mblock.use / 120,
s->mblock.total, s->mblock.max, s->mblock.fail);
tprint(buf, 16, 5);
sprintf(buf, "%6d%6d%6d%6d%7d%8d%8d%8d",
s->dblock.use,
sum10.dblock.use / 10, sum30.dblock.use / 30, sum60.dblock.use / 60,
sum120.dblock.use / 120,
s->dblock.total, s->dblock.max, s->dblock.fail);
tprint(buf, 16, 6);
for (i=0; i<NCLASS; ++i) {
mem += s->dblk[i].use * rbsize[i];
sprintf(buf, "%6d%6d%6d%6d%7d%8d%8d%8d",
s->dblk[i].use,
sum10.dblk[i].use / 10, sum30.dblk[i].use / 30,
sum60.dblk[i].use / 60, sum120.dblk[i].use / 120,
s->dblk[i].total, s->dblk[i].max, s->dblk[i].fail);
tprint(buf, 16, 9 + i);
}
sprintf(buf, "%d/%d Kbytes", kbytes(mem), kbytes(total));
tprint(buf, 23, 23);
calls++;
sprintf(buf, "Calls=%d", calls);
tprint(buf, 10, 0);
}
/*
* add a to be, leave result in b
*
* N.B. Assumes that elements are ints
*/
addstrst(a, b)
register alcdat* a;
register alcdat* b;
{
register i;
for (i=sizeof(struct strstat)/sizeof(*a); i--; (b++)->use += (a++)->use)
;
}
/*
* subtract a from be, result in b
*/
substrst(a, b)
register alcdat* a;
register alcdat* b;
{
register i;
for (i=sizeof(struct strstat)/sizeof(*a); i--; (b++)->use -= (a++)->use)
;
}
/*
* multiply a by b, result in a
*/
mulstrst(a, b)
register alcdat* a;
register int b;
{
register i;
for (i=sizeof(struct strstat)/sizeof(*a); i--; (a++)->use *= b)
;
}
# endif /* SAVECNT */
/*
* nasty cleanup
*/
error(s)
char* s;
{
perror(s);
done();
}
/*
* nice cleanup
*/
done()
{
echo(1);
cbreak(0);
delay(1);
tprint("", cols -1, lines - 1);
printf("\n");
exit(0);
}
/*
* read all once only stuff from kmem
*/
readstuff()
{
register i;
if (!nl[NL_RBSIZE].n_value) {
printf("%s: no value\n", nl[NL_RBSIZE].n_name);
exit(1);
}
if (!nl[NL_STRST].n_value) {
printf("%s: no value\n", nl[NL_STRST].n_name);
exit(1);
}
# ifdef sun
if (!nl[NL_NDBLKS].n_value) {
printf("%s: no value\n", nl[NL_NDBLKS].n_name);
# else
if (!nl[NL_V].n_value) {
printf("%s: no value\n", nl[NL_V].n_name);
# endif
exit(1);
}
if (!nl[NL_DBALLOC].n_value) {
printf("%s: no value\n", nl[NL_DBALLOC].n_name);
exit(1);
}
if (!nl[NL_NMBLOCK].n_value) {
printf("%s: no value\n", nl[NL_NMBLOCK].n_name);
exit(1);
}
if (lseek(fd, nl[NL_RBSIZE].n_value, 0) == -1)
error("lseek");
if (read(fd, rbsize, sizeof(rbsize)) != sizeof(rbsize))
error("read");
# ifdef sun
if (lseek(fd, nl[NL_NDBLKS].n_value, 0) == -1)
error("lseek");
if (read(fd, cnt, sizeof(cnt)) != sizeof(cnt))
error("read");
# else
if (lseek(fd, nl[NL_V].n_value, 0) == -1)
error("lseek");
if (read(fd, &v, sizeof(v)) != sizeof(v))
error("read");
# endif
# ifdef sun
if (lseek(fd, nl[NL_DBALLOC].n_value, 0) == -1)
error("lseek");
if (read(fd, &nl[NL_DBALLOC].n_value, sizeof(int)) != sizeof(int))
error("read");
# endif
if (lseek(fd, nl[NL_DBALLOC].n_value, 0) == -1)
error("lseek");
if (read(fd, dballoc, sizeof(dballoc)) != sizeof(dballoc))
error("read");
if (lseek(fd, nl[NL_NMBLOCK].n_value, 0) == -1)
error("lseek");
if (read(fd, &nmblock, sizeof(nmblock)) != sizeof(nmblock))
error("read");
# ifdef sun
if (lseek(fd, nl[NL_STRST].n_value, 0) == -1)
error("lseek");
if (read(fd, &nl[NL_STRST].n_value, sizeof(int)) != sizeof(int))
error("read");
# endif
}
//E*O*F sw.c//
echo x - term.h
cat > "term.h" << '//E*O*F term.h//'
# ifndef _TERM_H_
#include <stdio.h>
#include <sgtty.h>
char *getenv();
char *tgetstr();
char PC;
short ospeed;
short lines;
short cols;
char ceolbuf[20];
char clbuf[20];
char pcbuf[20];
char cmbuf[20];
#undef putchar
int putchar();
char term_buf[1024];
# endif _TERM_H_
//E*O*F term.h//
echo x - termcap.c
cat > "termcap.c" << '//E*O*F termcap.c//'
/*
* copyright (C) 1986 by Larry McVoy
* MUST be distributed in source form only.
*/
# include "term.h"
char* tgoto();
/*------------------------------------------------------------------15/Dec/86-*
* init_term - read in the termcap stuff
*----------------------------------------------------------------larry mcvoy-*/
termcap()
{
char *cp = getenv("TERM");
char *foo;
char garbage[10];
struct sgttyb tty;
gtty(1, &tty);
ospeed = tty.sg_ospeed;
if (cp == (char *) 0)
return -1;
if (tgetent(term_buf, cp) != 1)
exit(1);
foo = garbage;
foo = tgetstr("pc", &foo);
if (foo)
PC = *foo;
foo = clbuf;
tgetstr("cl", &foo);
foo = ceolbuf;
tgetstr("ce", &foo);
foo = cmbuf;
tgetstr("cm", &foo);
lines = tgetnum("li");
cols = tgetnum("co");
return 0;
}
/* clear to end of line */
ceol(col, row)
{
char *foo = tgoto(cmbuf, col, row);
write(1, foo, strlen(foo));
tputs(ceolbuf, 1, putchar);
}
/* clear screen */
clear()
{
tputs(clbuf, lines, putchar);
}
/*------------------------------------------------------------------15/Dec/86-*
* tputchar(c, col, row) - put a single char on the screen
*
* Inputs ----> (char), (int), (int)
*
* Bugs ------> Assumes that the coords make sense
*
* Revisions:
*----------------------------------------------------------------larry mcvoy-*/
tputchar(c, col, row)
char c;
{
register char* foo;
foo = tgoto(cmbuf, col, row);
tputs(foo, lines, putchar);
write(1, &c, 1);
}
/*------------------------------------------------------------------15/Dec/86-*
* tprint(s, col, row) - put a string on the screen
*
* Inputs ----> (char), (int), (int)
*
* Results ---> Puts the string out iff it will fit.
*
* Revisions:
*----------------------------------------------------------------larry mcvoy-*/
tprint(s, col, row)
register char* s;
{
register char* foo;
if (row > lines || col > cols)
return -1;
if (strlen(s) > cols - col)
return -2;
foo = tgoto(cmbuf, col, row);
tputs(foo, lines, putchar);
return write(1, s, strlen(s));
}
/* fake putchar for tputs */
putchar(c)
char c;
{
write(1, &c, 1);
}
//E*O*F termcap.c//
echo Possible errors detected by \'wc\' [hopefully none]:
temp=/tmp/shar$$
trap "rm -f $temp; exit" 0 1 2 3 15
cat > $temp <<\!!!
17 53 336 Makefile
57 120 878 mode.c
63 359 2087 sw.1
563 1521 12403 sw.c
19 36 278 term.h
104 281 2203 termcap.c
823 2370 18185 total
!!!
wc Makefile mode.c sw.1 sw.c term.h termcap.c | sed 's=[^ ]*/==' | diff -b $temp -
exit 0
---
Larry McVoy, Sun Microsystems (415) 336-7627 ...!sun!lm or lm@sun.com
-----------------------------
From: iccad <adley@herbie.misemi>
Subject: nested loops
Date: 9 Aug 90 19:17:28 GMT
To: unix-wizards@sem.brl.mil
Hi,
We are trying to write a Bourne shell script that includes two
nested loops as follows
!# /bin/sh
this="one two three"
that="four five six seven"
them="eight nine ten"
all="this that them"
#
for i in $all
do
for j in $`echo $i`
do
echo $i $j
done
done
we want (and expected!) the output:
this one
this two
this three
that four
that five
that six
that seven
them eight
them nine
them ten
The problem lies in the $`echo $i` statment
the `echo $i` preforms as expected and the result is one of this,
that, or them
the $ infront of this statment however is taken as a literal $
and does not return the value of the variable this or that or them
instead it returns $this or $that or $them.
Does anybody know why this happens or how we can get the results
that would be expected here (with the exception of doing it in a
C shell or in a C program).
Thanks.
-----------------------------
From: Gilles Courcoux <gilles@pase60.convergent.com>
Subject: Re: nested loops
Date: 10 Aug 90 16:15:51 GMT
Sender: root@risky.convergent.com
To: unix-wizards@sem.brl.mil
In article <4103@herbie.misemi> you wrote:
>The problem lies in the $`echo $i` statment
Right, double variable expansion like that is resolved through the use
of the eval(1) command as in :
eval echo '$'$i
When the shell read the command, it expands it into
eval echo $them # the first time !
and then eval(1) do his job : evaluating its arguments, including
variables expansion and then execute the command which is by now :
echo one two three
The echo(1) command is needed because eval(1) then exec(2)utes its
first argument.
Your script become :
this="one two three"
that="four five six seven"
them="eight nine ten"
all="this that them"
#
for i in $all
do
for j in `eval echo '$'$i`
do
echo $i $j
done
done
Have a nice day,
Gilles Courcoux E-mail: sun!pyramid!ctnews!pase60!gilles
Unisys Network Computing Group Phone: (408) 435-7692
-----------------------------
From: Chet Ramey <chet@cwns1.INS.CWRU.Edu>
Subject: Re: nested loops
Date: 10 Aug 90 19:28:41 GMT
Sender: news@usenet.ins.cwru.edu
To: unix-wizards@sem.brl.mil
In article <4103@herbie.misemi> adley@herbie.misemi ( iccad) writes:
$ !# /bin/sh
$ this="one two three"
$ that="four five six seven"
$ them="eight nine ten"
$ all="this that them"
$ #
$ for i in $all
$ do
$ for j in $`echo $i`
$ do
$ echo $i $j
$ done
$ done
$ The problem lies in the $`echo $i` statment
$ the `echo $i` preforms as expected and the result is one of this,
$ that, or them
$ the $ infront of this statment however is taken as a literal $
$ and does not return the value of the variable this or that or them
$ instead it returns $this or $that or $them.
Use `eval'.
Chet
--
Chet Ramey ``Levi Stubbs' tears run down
Network Services Group his face...''
Case Western Reserve University
chet@ins.CWRU.Edu
-----------------------------
From: Mitch Wright <mitch@hq.af.mil>
Subject: waitpid() ???
Date: 10 Aug 90 04:20:07 GMT
Sender: mitch@hq.af.mil
To: unix-wizards@sem.brl.mil
Greetings!
I was recently flipping through the source of ksh(1), humbly
admiring the work of David Korn, when I came across a function called
waitpid(). I quickly grep'ed through the code to see if I could find
where this function was defined, since I was not aware of a system call
by this name. Well, I found no definition for this call in the code or
in the few SYSV programming manuals that I have. Does anyone have an
idea exactly what this call does? Since it is in the middle of the job
control routines, I'd assume it was similar to wait3() in the Bezerkely
world, but the parameters seem to be out of whack, and all three of them
are integers instead of 1 int, 1 union wait *, and a struct rusage *.
A man-page would be fine, but I'd prefer not only a man page, but
a *real* description of what this puppy does.
Thanks!
--
..mitch
mitch@hq.af.mil (Mitch Wright) | The Pentagon, 1B1046 | (202) 695-0262
The two most common things in the universe are hydrogen and stupidity,
but not necessarily in that order.
-----------------------------
From: Boy named Superuser <root@storm.uucp>
Subject: unix sys v - uptime question
Date: 10 Aug 90 06:00:43 GMT
To: unix-wizards@sem.brl.mil
Does anyone out there know how to get Unix sys V/386 (sco) to display
load averages. The man pages say that uptime "displays the load averages
over 1 5 and 15 minutes" on "systems that maintain the necessary data."
However, I cannot seem to find out how to get the system to keep the
necessary data. Can anyone out there help?
Thanks!
root@storm.uucp@skinner.cs.uoregon.edu
-----------------------------
From: Devon Tuck <tuck@iris.ucdavis.edu>
Subject: Interesting keyboard read problem (ioctl, function keys)
Date: 10 Aug 90 08:10:33 GMT
Sender: usenet@ucdavis.ucdavis.edu
To: unix-wizards@sem.brl.mil
Hey wizards,
I have been working with an intersting problem... How to write a keyboard
input routine that does not mess up its' transmission of repeated function
keys. You might have noticed that even in vi, and in the C-shell, if you
sit on an arrow key or some other function key that maps to a character
sequence, you get intermittent beeps, or stray characters, respectively.
I am porting an editor for a bunch of users who are in deep wedlock with
their function keys, and they MUST be able to sit on their little arrow
keys and not lose any characters, BUT character throughput must be VERY
FAST.
The problem is that this editor is very bulky, and spends too much time
away from the keyboard input routine, so that if I do the logical thing
and set VMIN=1 and VTIME=0, portions of the home key sequence (<ESC>[H),
for example, get split across network packets and arrive with too much gap
for the keyboard driver to consider it a valid screen movement sequence.
Has anyone solved this problem? I think I might have it with a routine that
forks on its' first call, after setting up a pipe and ioctl calls, (VMIN=0,
VTIME=0) and thus leaves a small subprocess running alongside the editor
acting as a slave to the keyboard and sending all characters into a pipe
to be read at the leasure of the main character input routine.
How do other editors do it? How do Crisp, emacs, etc. handle this? (as I
mentioned, vi doesn't..)
Thanks,
Devon Tuck
tuck@iris.ucdavis.edu
PS - Incidentally, when I use a straight character read with VMIN>=1,
VTIME=1 the input is still too slow.
-----------------------------
From: Steve Perryman <skp@stl.stc.co.uk>
Subject: sockets and signals (in C)
Date: 10 Aug 90 08:45:16 GMT
Sender: news@stl.stc.co.uk
To: unix-wizards@sem.brl.mil
Does anyone know of a way to set up a signal handler such that if a flood
of data comes in to a socket, the SIGIO/SIGPOLL (maybe even SIGURG) signal
can invoke a handler fast enough such that a variable can be incremented to
represent the correct number of data items at the socket.
The signal handler will be :
void catch()
{
signal(SIGIO,catch) ;
count++ ;
...
/* Process the signal */
...
}
I've used fcntl to allow the socket to interrupt :
fcntl(sock,F_SETOWN,getpid()) ;
fcntl(sock,F_SETFL,F_ASYNC) ;
...
...
This works but it can't log the correct number of items received if they come
in as bursts of data (5+ items per burst). Can this timing problem be resolved
using SIGIO , or is another way required ???
skp
-----------------------------
From: Larry McVoy <lm@snafu.sun.com>
Subject: Re: sockets and signals (in C)
Date: 10 Aug 90 18:49:12 GMT
Sender: news@sun.eng.sun.com
To: unix-wizards@sem.brl.mil
In article <3304@stl.stc.co.uk> "Steve Perryman " <skp@stl.stc.co.uk> writes:
>
>Does anyone know of a way to set up a signal handler such that if a flood
>of data comes in to a socket, the SIGIO/SIGPOLL (maybe even SIGURG) signal
>can invoke a handler fast enough such that a variable can be incremented to
>represent the correct number of data items at the socket.
>
>This works but it can't log the correct number of items received if they come
>in as bursts of data (5+ items per burst). Can this timing problem be resolved
>using SIGIO , or is another way required ???
This can't be done with Unix signals. Unix signals don't stack, i.e., if
you hit yout interrupt character several times before the kernel delivers
the signal, the application will only see one signal.
About the best you can do for you application is to use sigio as a hint that
there is data waiting and schedule a timeout every second or so to collect
what you might have missed. It's also a good idea to code your processing
like so:
for ( ;; ) {
sigpause(0);
while (more_data()) {
process_data();
}
}
rather than
for ( ;; ) {
sigpause(0);
if (more_data()) {
process_data();
}
}
---
Larry McVoy, Sun Microsystems (415) 336-7627 ...!sun!lm or lm@sun.com
-----------------------------
From: Kishore Seshadri <kseshadr@quasar.intel.com>
Subject: Re: Re.: UNdeleting files
Date: 10 Aug 90 14:51:06 GMT
Sender: news@inews.intel.com
To: unix-wizards@sem.brl.mil
In article <7410002@hpfcmgw.HP.COM>, munir@hpfcmgw (Munir Mallal) writes:
>>>A similar thing has just happened here, and we don't have fsdb either.
>>>The machine has been untouched since the directory was deleted.
>>>Any suggestions ?
>>
> >Whether done with fsdb or not, the task is to read the disk
> >partition block by block, check each block to determine whether
> >it's part of the data to be recovered, and reassemble the recovered
> >blocks.
>
>You can use adb if you have it, but will have to do a lot of math to determine
>offsets etc.
>
I have a binary file modifier called fm that I pulled off comp.sources.misc
that can be used to edit devices and binary files. Once again if you do the
math beforehand this program may be of help in this situation. The devices
can be edited in either hex or ascii modes and simple string searches can be
handled. You should probably have a good understanding of the way the file
system has been implemented before fooling with this.
Kishore Seshadri
----------------------------------------------------------------------------
Kishore Seshadri <kseshadr@mipos3.intel.com> or <..!intelca!mipos3!kseshadr>
"The nice thing about standards is that you have so many to choose from."
-----------------------------
From: Scott McGregor <mcgregor@hemlock.atherton.com>
Subject: seeking information about file system details.
Date: 10 Aug 90 17:12:33 GMT
Sender: news@athertn.atherton.com
To: unix-wizards@sem.brl.mil
I am curious as to how accesses to multiple concurrent types of file
systems are implemented under SysV and BSD. I've read the Bach
book and the BSD book, as well as books on device drivers. But what
I am more interested in is at the switchable file system layer. Explanations
of what goes on in the following example are welcome, recommendations
of books that cover this stuff is even more heartily desired.
I know that mount takes a file type. I know how the file system
tree is traced using inodes, and I have heard of vnodes (which is
what I think I want to know more about) but I haven't found anything
written on vnodes. I am aware that several vendors support multiple
varieties of file systems (Bell, BSD, NFS, MS-DOS) all accessable on
the same system, and the files on them can be accessed using standard
o/s calls and stdio library routines.
I guess what I am interested in is if I have a non-unix file system
and I want to allow the this file system to be mounted as a unix
file system, and accessed using open, creat, read, write, close, et al,
what interface translators would I have to create between my own
file system and the unix system calls, and how and where would I
add typically add these translators. I presume that a new type
would have to be tested for in mount, and that the open, etc. commands
would have to know what type of file system they were operating on
and that a case statement switch would have to be supported by them for each
new type of file system to be supported.
Is this correct, or is there some other way that the switching between
file systems is handled.
Mail can be directed to:
mcgregor@atherton.com or ...!sun!atherton!mcgregor
Scott McGregor
Atherton Technology
-----------------------------
From: Chris Bertin <chrisb@risky.convergent.com>
Subject: evaluating ${10} and above in sh/ksh
Keywords: sh, ksh, eval
Date: 10 Aug 90 17:58:37 GMT
To: unix-wizards@sem.brl.mil
There doesn't seem to be a way, in sh or ksh, to evaluate $10 and higher.
$10 and higher are evaluated as ${1}0, ${1}1, etc...
instead of ${10}, ${11}, etc...
I have tried many different ways and they all fail. Do you know one
that will work?
#! /bin/sh
set a b c d e f g h i j k l
arg=0
while [ $arg -le $# ]; do
echo "evaluating \$$arg"
eval echo $"$arg"
eval echo $"${arg}"
eval echo "$`eval echo $arg`"
# Now, some of the crazy things I tried.
# ( The parens are there when eval causes an error )
echo "\${$arg} results in \c"
( eval echo "\${$arg}" )
echo "$`echo '{'``eval echo $arg``echo '}'` results in \c"
( eval echo "$`echo '{'``eval echo $arg``echo '}'`" )
arg=`expr $arg + 1`
done
--
Chris Bertin | chrisb@risky.Convergent.COM
Unisys | or
(408) 435-3762 | ...!uunet!pyramid!ctnews!risky!chrisb
-----------------------------
From: Chet Ramey <chet@cwns1.cwru.edu>
Subject: Re: How variables can be specified as arguments
Date: 10 Aug 90 19:24:41 GMT
Sender: news@usenet.ins.cwru.edu
To: unix-wizards@sem.brl.mil
In article <7298@helios.TAMU.EDU> skdutta@cs.tamu.edu (Saumen K Dutta) writes:
$ read_KEY1 "key"
$
$ should define a new variable called key and
$ assigns it's value according to what user types.
$
$ I am not able to solve this ! Please help me
Use `eval'.
Chet
--
Chet Ramey ``Levi Stubbs' tears run down
Network Services Group his face...''
Case Western Reserve University
chet@ins.CWRU.Edu
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: ln -f
Date: 10 Aug 90 20:19:01 GMT
To: unix-wizards@sem.brl.mil
>Why don't the versions of ln that you know of on 4.3 BSD and SunOS 4
>use the rename system call?
Because they're named "ln", not "mv".
"rename()" is *NOT* an atomic operation that removes the target and
makes an *additional* link from the source with the name of the target.
It's an atomic operation that *renames* the source to the target, and if
it succeeds does *not* leave the source behind.
-----------------------------
From: "David J. MacKenzie" <djm@eng.umd.edu>
Subject: Re: ln -f
Date: 10 Aug 90 22:54:43 GMT
Sender: The News System <news@eng.umd.edu>
To: unix-wizards@sem.brl.mil
> Why don't the versions of ln that you know of on 4.3 BSD and SunOS 4
> use the rename system call?
Because rename doesn't do the same thing as ln.
If before you run ln, the file has n links, after you run ln
successfully the file will have n + 1 links.
If you just rename the file, it will still have n links, but one of
them will be different from before.
--
David J. MacKenzie <djm@eng.umd.edu> <djm@ai.mit.edu>
-----------------------------
End of UNIX-WIZARDS Digest
**************************postmaster@ecf.ncsl.nist.gov (SMTP MAILER) (08/12/90)
----Reason for mail failure follows----
Sending mail to host ecf.ncsl.nist.gov :
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550 User "ise.ncsl.nist.gov" Unknown.
----Transcript of message follows----
Date: 12 Aug 90 06:39:00 EST
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#114
To: "ise.ncsl.nist.gov" <ise.ncsl.nist.gov@ecf.ncsl.nist.gov>
Return-Path: <unixwiz-request@ecf.ncsl.nist.gov>
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Date: Sun, 12 Aug 90 05:45:05 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#114
Message-ID: <9008120545.aa06856@SEM.BRL.MIL>
UNIX-WIZARDS Digest Sun, 12 Aug 1990 V10#114
Today's Topics:
Re: Help needed with System V message queues
Re: Cron - First Saturday of the month
waitpid() ???
seeking information about file system details.
Re: cd failure killing script [Re: Interactive 2.2 File zapper]
Re: sockets and signals (in C)
Re: nested loops
Re: ln -f
Re: Getting CPU information on unterminatted child processes
Reading escape sequences (arrow keys and escape alone)
-----------------------------------------------------------------
From: George Bogatko <bogatko@lzga.att.com>
Subject: Re: Help needed with System V message queues
Keywords: SYSV messagequeue
Date: 8 Aug 90 16:51:25 GMT
To: unix-wizards@sem.brl.mil
Postnews (or something) trashed the ending of the message queue article.
Here's the ending.
******
When sending messages, the third parameter must be the size of
the actual message, not the size of the 'struct msgbuf', which
will be sizeof(long) bytes bigger. If you don't pay attention
to this, you will get message trashing. I can't recall now how,
when, or why this happens, but I guarantee that it will be mysterious,
and usually fatal.
struct msgbuf {
long mtype; /* message type */
char mtext[1]; /* message text */
};
So the safe way to use 'msgsnd' is:
typedef struct {
long mtype;
struct {
char buf[10];
int xxx;
double yyy;
etc...
} mtext;
} MSG;
MSG message;
1. msgsnd( msqid, &message, sizeof(message.mtext), 0);
OR
2. msgsnd( msqid, &message, sizeof(message)-sizeof(long), 0);
I prefer #1.
I also prefer to send message with the fourth parameter as 0. This will
make the message block if there is no room at the time. It is more normal
for the message to block in a heavily loaded system then not, so you
will probably NOT want to die if you can't send the message because
there's no room. If you are worried about deadlock, put in an
alarm call so you can time out.
When receiving messages, check for EINTR if you get a -1.
You will usually want to just wrap around and try again if you get
an interrupt (usually from an alarm call, or some other friendly signal).
Hope this (long-winded) yakking helps somebody.
GB
-----------------------------
From: Bob Strait <rls@svcs1.uucp>
Subject: Re: Cron - First Saturday of the month
Date: 9 Aug 90 17:13:32 GMT
To: unix-wizards@sem.brl.mil
In article <19744@orstcs.CS.ORST.EDU> curt@oce.orst.edu (Curt Vandetta) writes:
> I'm wondering if anyone has a way of making cron run a job on the
> first Saturday of every month?
>
How about running your job each of the first seven days of every
month, and have the job first test whether it's Saturday and
exit if it's not. There are several easy ways to do the test:
'date | grep Sat' comes to mind.
--
BUBBA (aka Bob Strait) ...!mips!svcs1!rls
Silicon Valley Computer Society
Sunnyvale, CA
--
-----------------------------
From: Bob McGowen x4312 dept208 <bob@wyse.wyse.com>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 02:40:29 GMT
Sender: news@wyse.wyse.com
To: unix-wizards@sem.brl.mil
In article <1990Aug8.185745.16606@iwarp.intel.com> merlyn@iwarp.intel.com (Randal Schwartz) writes:
>In article <19744@orstcs.CS.ORST.EDU>, curt@oce (Curt Vandetta) writes:
>| I'm wondering if anyone has a way of making cron run a job on the
>| first Saturday of every month?
>
>3 4 1-7 * 6 command
>
>to make 'command' run at 4:03am... adjust the first two fields as
>necessary. Remember, the parameters are "and"-ed together.
...flame deleted
My documentation states that a line like the one you have provided
would cause the command to run on EVERY Saturday as well as on each
of the first seven days in the month.
My flame--
I would be very interested if you could provide a cron only method
of getting my cron to execute on the first Saturday (or any other
day) such that it executes on that single day only. My attempts at
solving this have been to combine cron to run the command on Saturday
and have command be a script that checks the date to be sure it is
less than or equal to 7. But this only works for the first 13 days
so I have to figure out the next exclusion, probably to limit between
a start and stop. In any case, getting cron to do what Curt wants is
a little more difficult. Possibly (probably, I think) even wizard
caliber.
Bob McGowan (standard disclaimer, these are my own ...)
Product Support, Wyse Technology, San Jose, CA
..!uunet!wyse!bob
bob@wyse.com
-----------------------------
From: Ronald S H Khoo <ronald@robobar.co.uk>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 19:05:17 GMT
To: unix-wizards@sem.brl.mil
In article <1990Aug10.063819.5253@iwarp.intel.com> merlyn@iwarp.intel.com (Randal Schwartz) writes:
> Sigh. Sorry. I'll crawl under my rock now. Cron's only for the
> heavyweights, anyway.
System V cron isn't just for heavyweights, though, it's got per-user
crontabs, remember, so joe-random-non-wizard who has his own crontab
has to understand the manpage. Sigh.
Someone once mentioned wanting to write a System V-like cron in perl
so he could have per-user crontabs on his machine. I wonder who
it was, and how he parsed the manpage ?
--
Eunet: Ronald.Khoo@robobar.Co.Uk Phone: +44 81 991 1142 Fax: +44 81 998 8343
Paper: Robobar Ltd. 22 Wadsworth Road, Perivale, Middx., UB6 7JD ENGLAND.
-----------------------------
From: kpc <kpc00@juts.ccc.amdahl.com>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 21:49:09 GMT
Sender: kpc00@ccc.amdahl.com
To: unix-wizards@sem.brl.mil
In article <1990Aug10.063819.5253@iwarp.intel.com>
merlyn@iwarp.intel.com (Randal Schwartz) writes:
So, they really mucked up when they OR-ed in that day-of-week
field.
Sigh. Sorry. I'll crawl under my rock now. Cron's only for the
heavyweights, anyway.
Because it's job security through obscurity :-)? Your posting was
good. One might hope that HLL boolean expressions were at least
considered in the design of cron. (I hope that this offends nobody.
In particular, I hope that the designer of cron is not reading this or
is not offended -- it really is a wonderful tool, but why was
APL-minus-minus chosen as the time description language? :-))
For UNIX historians: Was an HLL expression syntax ever considered?
(Or was the original machine thought to be too slow for it?)
Also, now that the OR is in there, which of merlyn's possibilities was
correct? It makes one wonder what things, if any, are not possible in
cron without putting something in the command to be executed.
--
Neither representing any company nor, necessarily, myself.
-----------------------------
From: Randal Schwartz <merlyn@iwarp.intel.com>
Subject: Re: Cron - First Saturday of the month
Date: 10 Aug 90 22:43:31 GMT
6@star.cs.vu
Sender: news@iwarp.intel.com
To: unix-wizards@sem.brl.mil
In article <7286@star.cs.vu.nl>, maart@cs (Maarten Litmaath) writes:
| The code:
[deleted to protect my eyes, but it *is* the code I remember ...]
| The conclusion: the manual and the code contradict each other!
| The example
|
| 0 0 1,15 * 1
|
| ...will run the job on each monday whose date is either the 1st or the 15th!
| It might be too late to fix the manual... (Grrrr!)
Yes, this is my point. Actually, what I think happened is that you
posted the V7-derived cron, and Sunos4.1 went to the user-crontab
System (blech) V cron, and I suspect that they put some widgets in
there to do this stupid "OR" logic that I complained about in my last
two postings.
Anyone with access to system V source care to comment? Are there some
yucky kludges in there?
Just another System V disliker,
--
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/
-----------------------------
From: David Canzi <dmcanzi@watserv1.waterloo.edu>
Subject: Re: Cron - First Saturday of the month
Date: 11 Aug 90 03:08:18 GMT
To: unix-wizards@sem.brl.mil
In article <1990Aug8.214539.1264@watserv1.waterloo.edu> I wrote:
>In a sh script, it can be done by:
>
>if [ `date | sed 's/^... ... *\([^ ]*\) .*/\1/'` -le 7 ]; then
> ...
>fi
This is better done using awk:
if [ `date | awk '{print $3}'` -le 7 ]; then
...
fi
--
David Canzi
-----------------------------
From: Mitch Wright <mitch@hq.af.mil>
Subject: waitpid() ???
Date: 10 Aug 90 04:20:07 GMT
Sender: mitch@hq.af.mil
To: unix-wizards@sem.brl.mil
Greetings!
I was recently flipping through the source of ksh(1), humbly
admiring the work of David Korn, when I came across a function called
waitpid(). I quickly grep'ed through the code to see if I could find
where this function was defined, since I was not aware of a system call
by this name. Well, I found no definition for this call in the code or
in the few SYSV programming manuals that I have. Does anyone have an
idea exactly what this call does? Since it is in the middle of the job
control routines, I'd assume it was similar to wait3() in the Bezerkely
world, but the parameters seem to be out of whack, and all three of them
are integers instead of 1 int, 1 union wait *, and a struct rusage *.
A man-page would be fine, but I'd prefer not only a man page, but
a *real* description of what this puppy does.
Thanks!
--
..mitch
mitch@hq.af.mil (Mitch Wright) | The Pentagon, 1B1046 | (202) 695-0262
The two most common things in the universe are hydrogen and stupidity,
but not necessarily in that order.
-----------------------------
From: Scott McGregor <mcgregor@hemlock.atherton.com>
Subject: seeking information about file system details.
Date: 10 Aug 90 17:12:33 GMT
Sender: news@athertn.atherton.com
To: unix-wizards@sem.brl.mil
I am curious as to how accesses to multiple concurrent types of file
systems are implemented under SysV and BSD. I've read the Bach
book and the BSD book, as well as books on device drivers. But what
I am more interested in is at the switchable file system layer. Explanations
of what goes on in the following example are welcome, recommendations
of books that cover this stuff is even more heartily desired.
I know that mount takes a file type. I know how the file system
tree is traced using inodes, and I have heard of vnodes (which is
what I think I want to know more about) but I haven't found anything
written on vnodes. I am aware that several vendors support multiple
varieties of file systems (Bell, BSD, NFS, MS-DOS) all accessable on
the same system, and the files on them can be accessed using standard
o/s calls and stdio library routines.
I guess what I am interested in is if I have a non-unix file system
and I want to allow the this file system to be mounted as a unix
file system, and accessed using open, creat, read, write, close, et al,
what interface translators would I have to create between my own
file system and the unix system calls, and how and where would I
add typically add these translators. I presume that a new type
would have to be tested for in mount, and that the open, etc. commands
would have to know what type of file system they were operating on
and that a case statement switch would have to be supported by them for each
new type of file system to be supported.
Is this correct, or is there some other way that the switching between
file systems is handled.
Mail can be directed to:
mcgregor@atherton.com or ...!sun!atherton!mcgregor
Scott McGregor
Atherton Technology
-----------------------------
From: Chip Salzenberg <chip@tct.uucp>
Subject: Re: cd failure killing script [Re: Interactive 2.2 File zapper]
Date: 10 Aug 90 17:40:46 GMT
To: unix-wizards@sem.brl.mil
According to davidsen@sixhub.UUCP (bill davidsen):
>Yes, only ksh gives you the choice of catching the failure.
Bash 1.05 also continues after a "cd" failure.
--
Chip Salzenberg at ComDev/TCT <chip@tct.uucp>, <uunet!ateng!tct!chip>
-----------------------------
From: Larry Wall <lwall@jpl-devvax.jpl.nasa.gov>
Subject: Re: cd failure killing script [Re: Interactive 2.2 File zapper]
Date: 11 Aug 90 19:10:53 GMT
To: unix-wizards@sem.brl.mil
In article <26C2F1A0.205B@tct.uucp> chip@tct.uucp (Chip Salzenberg) writes:
: According to davidsen@sixhub.UUCP (bill davidsen):
: >Yes, only ksh gives you the choice of catching the failure.
:
: Bash 1.05 also continues after a "cd" failure.
Likewise Perl. The idiom to catch the failure is
chdir $dir || die "Can't cd to $dir: $!\n";
Larry Wall
lwall@jpl-devvax.jpl.nasa.gov
-----------------------------
From: Larry McVoy <lm@snafu.sun.com>
Subject: Re: sockets and signals (in C)
Date: 10 Aug 90 18:49:12 GMT
Sender: news@sun.eng.sun.com
To: unix-wizards@sem.brl.mil
In article <3304@stl.stc.co.uk> "Steve Perryman " <skp@stl.stc.co.uk> writes:
>
>Does anyone know of a way to set up a signal handler such that if a flood
>of data comes in to a socket, the SIGIO/SIGPOLL (maybe even SIGURG) signal
>can invoke a handler fast enough such that a variable can be incremented to
>represent the correct number of data items at the socket.
>
>This works but it can't log the correct number of items received if they come
>in as bursts of data (5+ items per burst). Can this timing problem be resolved
>using SIGIO , or is another way required ???
This can't be done with Unix signals. Unix signals don't stack, i.e., if
you hit yout interrupt character several times before the kernel delivers
the signal, the application will only see one signal.
About the best you can do for you application is to use sigio as a hint that
there is data waiting and schedule a timeout every second or so to collect
what you might have missed. It's also a good idea to code your processing
like so:
for ( ;; ) {
sigpause(0);
while (more_data()) {
process_data();
}
}
rather than
for ( ;; ) {
sigpause(0);
if (more_data()) {
process_data();
}
}
---
Larry McVoy, Sun Microsystems (415) 336-7627 ...!sun!lm or lm@sun.com
-----------------------------
From: Chet Ramey <chet@cwns1.cwru.edu>
Subject: Re: nested loops
Date: 10 Aug 90 19:28:41 GMT
Sender: news@usenet.ins.cwru.edu
To: unix-wizards@sem.brl.mil
In article <4103@herbie.misemi> adley@herbie.misemi ( iccad) writes:
$ !# /bin/sh
$ this="one two three"
$ that="four five six seven"
$ them="eight nine ten"
$ all="this that them"
$ #
$ for i in $all
$ do
$ for j in $`echo $i`
$ do
$ echo $i $j
$ done
$ done
$ The problem lies in the $`echo $i` statment
$ the `echo $i` preforms as expected and the result is one of this,
$ that, or them
$ the $ infront of this statment however is taken as a literal $
$ and does not return the value of the variable this or that or them
$ instead it returns $this or $that or $them.
Use `eval'.
Chet
--
Chet Ramey ``Levi Stubbs' tears run down
Network Services Group his face...''
Case Western Reserve University
chet@ins.CWRU.Edu
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: ln -f
Date: 10 Aug 90 20:19:01 GMT
To: unix-wizards@sem.brl.mil
>Why don't the versions of ln that you know of on 4.3 BSD and SunOS 4
>use the rename system call?
Because they're named "ln", not "mv".
"rename()" is *NOT* an atomic operation that removes the target and
makes an *additional* link from the source with the name of the target.
It's an atomic operation that *renames* the source to the target, and if
it succeeds does *not* leave the source behind.
-----------------------------
From: "David J. MacKenzie" <djm@eng.umd.edu>
Subject: Re: ln -f
Date: 10 Aug 90 22:54:43 GMT
Sender: The News System <news@eng.umd.edu>
To: unix-wizards@sem.brl.mil
> Why don't the versions of ln that you know of on 4.3 BSD and SunOS 4
> use the rename system call?
Because rename doesn't do the same thing as ln.
If before you run ln, the file has n links, after you run ln
successfully the file will have n + 1 links.
If you just rename the file, it will still have n links, but one of
them will be different from before.
--
David J. MacKenzie <djm@eng.umd.edu> <djm@ai.mit.edu>
-----------------------------
From: "Jay A. Konigsberg" <jak@sactoh0.uucp>
Subject: Re: Getting CPU information on unterminatted child processes
Date: 11 Aug 90 09:43:04 GMT
To: unix-wizards@sem.brl.mil
In article <1990Aug7.215320.13715@mozart.amd.com> leight@mozart.amd.com (Timothy Leight) writes:
>I am interested in getting accurate cpu usage information
>on unterminated child processes. The getrusage() and/or times()
>system calls only return information on terminated children.
>
>What is the best method for getting this information?
>
Well, I don't know the best method, but I think I can point you in the
right direction (since no one else did).
ps -lf will provide much of the information needed, though it may not
produce enough and any way you invoke it (peopen or shell script), it
will be slow.
Another aproach is to get the information directly out of /dev/kmem.
However, all I know how to do there is get overall system usage
parameters. Specific information of /dev/kmem is probably system
specific and un-portable. However, the Sys V and Xenix 2.3.? header
file is: /usr/include/sys/sysinfo.h
Getting information about kernel level data structures on the net is
a little like asking for the moon, no one seems to have it. Anyway,
perhaps this post will generate a little discussion. I would like to
know more specifics about the Sys V kernel myself.
--
-------------------------------------------------------------
Jay @ SAC-UNIX, Sacramento, Ca. UUCP=...pacbell!sactoh0!jak
If something is worth doing, its worth doing correctly.
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: Getting CPU information on unterminatted child processes
Date: 11 Aug 90 21:24:08 GMT
To: unix-wizards@sem.brl.mil
>Getting information about kernel level data structures on the net is
>a little like asking for the moon, no one seems to have it.
No, it's more like asking for the moon if you're on Jupiter; the
appropriate response is "which moon"? Kernel-level data structures
differ between different UNIX implementations.
-----------------------------
From: David Wright <dwright@wheaton.uucp>
Subject: Reading escape sequences (arrow keys and escape alone)
Keywords: non-blocking i/o, timers, escape sequences
Date: 12 Aug 90 02:26:16 GMT
To: unix-wizards@sem.brl.mil
System: Ultrix 2.0, vt100 terminals.
I am currently writing a C program that takes as input an escape alone,
and escape sequences (such as the arrow keys generate, e.g. ^[[A). When my
program receives an escape I go into non-blocking mode to check and see if
there are any other key-strokes availabile. If there aren't then I assume
that an escape by itself has been pressed. If there are, I read them to
find out which arrow key was pressed (assuming it was an arrow-key).
Unfortunately, this doesn't work to well. If an arrow-key is pressed the
individual key-strokes sometimes arrive at a considerable interval. When I
check in non-blocking mode to see if there is a character after the initial
escape, the next character (e.g. "[") sometimes has not arrived yet, so
that it appears as though an escape only was pressed.
I have tried to read continuously in non-blocking mode after an escape was
pressed. This guarantees that I will see the arrow-key, if one was
pressed. However this makes for awkward parsing when I try to see whether
an escape only was pressed. If the user presses an escape, followed by a
regular character, I have provide for 'ungetting' that character in some
way. This is not too hard but seems to lack elegance. Also, it becomes very
difficult if the escape is followed by something like another arrow-key.
Then there are three characters available after the escape, and this is
a mess.
What I am wondering is if there is some elegant solution for waiting a set
period of time after esape is pressed? Then I could wait for a while, say
1/2 second, and check if there are any characters after the escape. I have
tried a sleep(1), but this can result in a wait of up to 2 seconds.
I know there is way of doing what I want to do on SYS V. (Turning off
ICANON and using VMIN and VTIME).
Please respond via E-mail, unless you think it's something everyone would
benefit from. I will sumarize. Sections of code welcomed.
Thanks in advance for your help,
David Wright, dwright@wheaton.uucp
-----------------------------
End of UNIX-WIZARDS Digest
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----Transcript of message follows----
Date: 13 Aug 90 06:45:00 EST
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#115
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From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#115
Message-ID: <9008130545.aa02296@SEM.BRL.MIL>
UNIX-WIZARDS Digest Mon, 13 Aug 1990 V10#115
Today's Topics:
Re: Help needed with System V message queues
Re: nested loops
evaluating ${10} and above in sh/ksh
Re: Getting CPU information on unterminatted child processes
Re: Cron - First Saturday of the month
-----------------------------------------------------------------
From: George Bogatko <bogatko@lzga.att.com>
Subject: Re: Help needed with System V message queues
Keywords: SYSV messagequeue
Date: 8 Aug 90 16:36:56 GMT
To: unix-wizards@sem.brl.mil
HI:
A while ago, I got sick of wondering what the tunables for messages meant.
The result was a writeup which was begun, interrupted, and never
finished. This is what remains of it. It is 500+ lines long, so you
may want to skip all this if message queues leave you cold. After it,
in a second posting is a 'pic' file of how messages are stored in memory.
This may answer some questions about message queues, and how they work.
If I see enough interest, I may finish the writeup.
************
OVERVIEW
In /etc/master.d there is a file, called msg that contains
the tunable parameters for the device driver that handles
the UNIXTM message queue system. This file contains lines
similar to the following:
MSGMAP = 100
MSGMAX = 2048
MSGMNB = 4096
MSGMNI = 50
MSGSSZ = 8
MSGTQL = 40
MSGSEG = 1024
The meaning of these parameters, as stated in the manual
Operations and Administration Series: Performance Mangement
under the chapter Tunable Parameters Definitions is:
MSGMAP specifies the size of the memory control map
used to manage message segments. If this
value is insufficient to handle the message
type facilities, a warning message is sent ot
the console.
MSGMAX specifies in bytes the maximum size of a
message sent. When receiving a message, a
value larger than this parameter can be used
to ensure that the whole message is received
and not truncated.
MSGMNB specifies the maximum length, in bytes of a
message queue. The owner of a facility can
lower this value, but only the superuser can
raise it.
MSGSEG Specifies the number of message segments in
the system. MSGSEG * MSGSSZ should be less
than 131,072 bytes (128 kilobytes).
MSGSSZ specifies the size in bytes of a message
segment as stored in memory. Each message is
stored in a contiguous message segment. The
larger the segments are, the greater the
chance of having wasted memory at the end of
each message. MSGSSZ * MSGSEG should be less
than 131,072 bytes (128 kilobytes).
MSGTQL specifies the number of message queue headers
on all message queues sytem-wide, and thus,
the number of outstanding messages.
These values are stored in a structure called "struct msginfo"
which looks like this:
struct msginfo {
int msgmap,
msgmax,
msgmnb,
msgmni,
msgssz,
msgtql;
ushort msgseg;
};
This structure is used when the MSG driver is initialized.
Notice that the values are stored as INTS. This bites you
in the butt later on when the value of 'msgmnb' is put
into 'msg_qbytes'.
All the structures described here are found in '/usr/include/sys/msg.h'
There are four data structures used in the message queue
universe.
struct msgbuf
This is actually a template used by the user to hold
the message; it is assumed (incorrectly) that the user
knows enough to re-write this template to suit their
needs. The structure given in the header file msg.h is
never used. The only thing that must be here is the
member "long mtype". which must always be the first
member. The template looks like this:
struct msgbuf {
long mtype; /* message type */
char mtext[1]; /* message text */
};
Notice that the size of mtext is one (1). This is not
enough size to hold anything useful.
Newcomers to UNIXTM messages almost always bark their
shins on this one.
struct msg
This is the structure that points to the address of the
actual message in the message pool. It looks like
this:
struct msg {
struct msg *msg_next;
long msg_type;
short msg_ts;
short msg_spot;
};
The message queue driver keeps these structures, called
message headers in an array, whose size is determined
by the tunable parameter MSGTQL. Each outstanding
message, i.e. a message that has been sent but not yet
received, has one of these headers associated with it.
Thus the number of outstanding messages handled by the
driver is determined by the setting of MSGTQL.
The members of the structure are used as:
msg_next
Even though these headers are in an array, they
are handled like a linked list. This member
points to the next header, which is located
somewhere in the array.
msg_type
This corresponds to the long mtype member of the
msgbuf structure shown above.
msg_ts
This is the precise length in bytes of the message
that is stored in the message pool.
msg_spot
This is the location in the message pool of the
message. Notice that it is not a pointer. It is
really an offset.
struct msqid_ds
This is the structure that keeps vital statistics about
a particular message queue that is being serviced by
the driver. It looks like this:
struct msqid_ds {
struct ipc_perm msg_perm
struct msg *msg_first;
struct msg *msg_last;
ushort msg_cbytes;
ushort msg_qnum
ushort msg_qbytes;
ushort msg_lspid;
ushort msg_lrpid;
time_t msg_stime;
time_t msg_rtime;
time_t msg_ctime;
};
The driver keeps these structures in an array, whose
size is determined by the tunable parameter MSGMNI.
Thus the maximum number of message queues handled by
the driver is determined by the setting of MSGMNI.
The members of the structure are used as:
msg_perm
This is a structure located in ipc.h that contains
various permissions and ids. It looks like this:
struct ipc_perm {
ushort uid; /* owner's user id */
ushort gid; /* owner's group id */
ushort cuid; /* creator's user id */
ushort cgid; /* creator's group id */
ushort mode; /* access modes */
ushort seq; /* slot usage sequence number */
key_t key; /* key */
};
This structure is used by all the drivers in the
IPC system. The meaning of these variables is
clear from their names, and the comments; except
for seq.
This variable holds a sequence number that is used
to determine the msqid that is returned from the
msgget() call. By constantly incrementing this
number, one can be sure that the same message
queue header will not have the same msqid returned
when it is re-allocated.
msg_first
This is a pointer to the first struct msg member
in the linked list of struct msg message headers.
msg_last
This is a pointer to the last struct msg member in
the linked list of struct msg message headers.
msg_cbytes
This is the total number of bytes currently on the
queue. It represents the accumulated total of all
the values of the struct msg member msg_ts in the
linked list of outstanding message headers for
that particular queue.
msg_qnum
This is how many messages are outstanding on the
queue; and thus how many struct msg message
headers are linked to this queue header.
msg_qbytes
This is an upper limit of how many bytes can be
outstanding on the queue. This is an arbitrary
value, which is set from the value of the tunable
parameter MSGMNB. This means that raising or
lowering this value does not alter how many total
messages you can have handled by the driver. That
is determined by the size of the message pool. This
value can be altered by either the owner/creator of
the message queue, or the super-user, without having
to change the value of MSGMNB.
msg_lspid
The process id of the last process to send a
message.
msg_lrpid
The process id of the last process to receive a
message.
msg_stime
The last time a message was put on this queue.
msg_rtime
The last time a message was taken off this queue.
msg_ctime
The last time anything at all happened regarding
this header.
The message pool
There is no formal name for the pool in the msg.h
structure. The message pool is an amorphous blob of
memory. It is obtained by a call to the kernel function
kseg() which returns the base address of a segment of kernel
memory. This address is cast to type paddr_t (physical
address type) which on the 3B2 line is a long. It is
treated as a contiguous array of single bytes. Think of it
as a char array.
This size of this blob is determined by multiplying the
values in the two tunable parameters MSGSEG and MSGSSZ.
The result of the multiplication is then rounded up to
the nearest page size. This size is passed as a
parameter to kseg().
The argument to kseg() is a request for pages of
memory, in the range 1 - 64. 64 pages (128K) is the
upper limit of memory that will be returned by kseg().
This is why the tunable parameters guide mentioned
above says:
"MSGSSZ * MSGSEG should be less than 131,072 bytes (128 kilobytes)."
SENDING A MESSAGE
Before diving in to how the driver handles messages, it
might be best to present a general picture of how
outstanding messages are stored.
Recall from part 1 that there are four data structures
involved in the process: struct msgbuf, struct msg, struct
msqid_ds, and the memory pool. Briefly, the msqid_ds
structure points to the first instance of a message header,
which is a msg structure. Each message header points to the
next message header in the linked list of outstanding
messages. Each message header contains the offset in the
memory pool where the actual message is being stored.
The memory pool is logically divided into segments (of size
MSGSSZ), and total number of these segments is of size
MSGSEG. When a message is actually stored, it will occupy
as much space as necessary, rounded up to the nearest
segment size. From this it can be seen that unless the
message size aligns with the MSGSSZ segment size, there will
be some wasted bytes associated with each stored message.
The enclosed diagram Mapping a Message Queue ID to a 28 Byte
Message in Kernal Memory displays the association of all
these data structures in the job of holding a 28 byte
message in memory.
**** SEE FOLLOWING POSTING FOR PIC FILE ****
3.1 Conversion of a user supplied message queue ID (msqid)
to a pointer to a struct msqid_ds queue header
This is a fundamental algorighm in the whole process, and is
called from many places in the driver;
algorithm 'msgconv'
convert msqid to msqid_ds structure
{
1. pointer = address of array,
offset by msqid
modulo MSGMNI
2. lock the reference to the structure
3. if(the structure is not in use) ||
the sequence number doesn't equal
the msqid divided by MSGMNI)
return EINVAL
4. return the pointer found in step 1.
}
step 1. convert msqid to pointer
Remember that the msqid_ds structures are held in an
array of size MSGMNI. Assuming that the call msgget()
works correctly (it does), the msqid that is returned
from that call will always be the result of an
incrementing sequence number (remember struct
ipc_perm.ushort seq?) times the value of MSGMNI, plus
the offset into the msqid_ds array of the assigned
message header. Thus if MSGMNI is 100, the sequence
number 3, and the offset 30, the message queue id
returned by msgget() would be 330.
The line that converts the msqid back to the offset is
simply:
qp = &msgque[id % msginfo.msgmni];
Which is to say that the offset of the array (here
msgque) is msqid modulo MSGMNI. In our example, this
would be 30, which is indeed the offset of the array.
step 2. Lock the reference to the structure
A parallel char array, of size MSGMNI is kept. Once
the offset is found, it is used to find the associated
lock value in this lock array. As long as this value is
1, the process sleeps (lines 1 and two following).
1 while (*lockp)
2 sleep(lockp, PMSG);
3 *lockp = 1;
When another process, which is using this message
header, is done, it sets the value of this lock to 0,
and issues a wakeup(). Our process then wakes up and
now finds the value to be 0. It then stops going to
sleep, and locks the value (line 3).
This is what allows message queues to act "atomicly"
step 3. check the msqid value for validity
The value of qp->msg_perm.seq is checked against the
value of msqid divided by MSGMNI and if they don't
match, then errno is set to EINVAL and the system call
returns with an error (-1). In our example, if the
msqid is 330, then 330/100 (in integer arithmetic)
yields 3, which is indeed the sequence number. Thus
the msqid is successfully converted to a valid and
active message header.
step 4. return the queue pointer
3.2 Sending_a_message
Sending a message consists of receiving a buffer from the
user, and putting it into the message pool, with proper
labeling so that a receive request can copy that message out
of the message pool.
algorithm 'msgsnd'
send a message
{
1. convert msqid to msqid_ds pointer (algorighm msgconv)
2. if(access denied by incorrect permissions)
return EACCES
3. if(byte count <= 0 || byte count > MSGMAX)
return EINVAL
4. copy the message type from the user area
return EFAULT on error
5. if(message type <= 0)
return EINVAL
GETRES:
6. if(queue has been removed or changed)
return EIDRM
7. if( (total bytes in queue > MSGMNB) ||
(no free msg headers available [MSGTQL])
{
8. if(IPC_NOWAIT set)
return EAGAIN
9. sleep
10. if(sleep was interrupted)
return EINTR
11. goto GETRES
}
12. call 'malloc()' to find free slot in
message pool.
13. if(no free space in message pool)
{
if(IPC_NOWAIT set)
return EAGAIN
sleep
if(sleep was interrupted)
return EINTR
goto GETRES
}
14. assuming all is OK, copy from user to
message pool.
15. if(system error during copy)
{
call 'mfree' to mark slot as free
return EFAULT
}
16. update 'msqid_ds' header
17. initialize 'msg' header
18. link 'msg' header into chain of
related 'msg' headers.
19. return 0
}
*****************
At this point I was interrupted by real work, and never returned to the
writeup. The "Bach Book" has a good writeup on this stuff.
A few points however:
MSGMAX is not MSGMNB. MSGMAX is the largest message you can send. You
can't find out the value of MSGMAX from the msqid_ds structure.
MSGMNB can be found out from "msg_qbytes". Recall from the above, that
you can reset this to a higher value if you are super-user
and always to a lower value if you are the owner.
What is important to note however is that this number has nothing to
do with capacity of the driver. It is just a number that is compared against.
MSGMNB is stored in "struct msginfo" as an INT, but when the driver is
initialized, it is transfered to "struct msqid_ds" in member "msg_qbytes"
which is a "ushort". Thus while some documentation may say that you
can have a high message queue maximum, you can only have the upper
limits of a ushort (65535). If you set MSGMNB to a higher value
than this, it will wrap, and you will wind up with a lower value.
If you want to increase the size of the message pool, increase
MSGSEG. NEVER INCREASE MSGSSZ. Recall from above:
"The memory pool is logically divided into segments (of size
MSGSSZ), and total number of these segments is of size
MSGSEG. When a message is actually stored, it will occupy
as much space as necessary, rounded up to the nearest
segment size. From this it can be seen that unless the
message size aligns with the MSGSSZ segment size, there will
be some wasted bytes associated with each stored message."
This means that if MSGSSZ is 50 bytes, and you have a 10 byte message,
you will occupy one slot, and have 40 bytes of wasted storage hanging
around. But if you keep the value of 8, then you will occupy 2 slots
and have 6 bytes of wasted storage hanging around.
See the following posting for a pic file of how this storage works.
In the msgsnd description above is:
12. call 'malloc()' to find free slot in
message pool.
13. if(no free space in message pool)
{
if(IPC_NOWAIT set)
return EAGAIN
sleep
if(sleep was interrupted)
return EINTR
goto GETRES
}
Notice that there no escape from this if the size of the message you are
trying to send is greater then the total amount of memory in the message
pool. Thus you can hang forever waiting for enough room to become
available. This will be allowed if MSGMNB is set to be greater than
( MSGSSZ * MSGSEG * (sizeof page on your machine (2048 on 3B's) ) ).
Be careful when setting the tunables!!!
When sending messages, the third parameter must be the size of
the actual message, not the size of the 'struct msgbuf', which
will be sizeof(long) bytes bigger. If you don't pay attention
to this, you will get message trashing. I can't recall now how,
when, or why this happens, but I guarantee that it will be mysterious,
and usually fatal.
struct msgbuf {
long mtype; /* message type */
char mtext[1]; /* message text */
};
So the safe way to use 'msgsnd' is:
typedef struct {
long mtype;
struct {
char buf[10];
int xxx;
double yyy;
etc...
} mtext;
} MSG;
MSG message;
1. msgsnd( msqid, &message, sizeof(message.mtext), 0);
OR
2. msgsnd( msqid, &message, sizeof(message)-sizeof(long), 0);
I prefer #1.
I also prefer to send message with the fourth parameter as 0. This will
make the message block if there is no room at the time. It is more normal
for the message to block in a heavily loaded system then not, so you
will probably NOT want to die if you can't send the message because
there's no room. If you are worried about deadlock, put in an
alarm call so you can time out.
When receiving messages, check for EINTR if you get a -1.
You will usually want to just wrap around and try again if you get
an interrupt (usually from an alarm call, or some other friendly signal).
Hope this (long-winded) yakking helps somebody.
GB
-----------------------------
From: George Bogatko <bogatko@lzga.att.com>
Subject: Re: Help needed with System V message queues
Keywords: SYSV messagequeue
Date: 8 Aug 90 16:38:08 GMT
To: unix-wizards@sem.brl.mil
HI:
here is the pic file for the previous article.
*******
.nf
.PS
scale=100
define t851 |
[ box invis ht 74 wid 320 with .sw at 0,0
"\fR\s16\&Mapping a Message Queue ID \f1\s0" at 160,62
"\fR\s16\&to A 28 Byte Message\f1\s0" at 160,37
"\fR\s16\&in Kernal Memory\f1\s0" at 160,12
] |
define t850 |
[ box invis ht 56 wid 82 with .sw at 0,0
"\fR\s12\&MESSAGE\f1\s0" at 41,47
"\fR\s12\&QUEUE\f1\s0" at 41,28
"\fR\s12\&ID\f1\s0" at 41,9
] |
define t849 |
[ box invis ht 96 wid 16 with .sw at 0,0
"\fR\s10\&M\f1\s0" at 8,88
"\fR\s10\&S\f1\s0" at 8,72
"\fR\s10\&G\f1\s0" at 8,56
"\fR\s10\&T\f1\s0" at 8,40
"\fR\s10\&Q\f1\s0" at 8,24
"\fR\s10\&L\f1\s0" at 8,8
] |
define t848 |
[ box invis ht 64 wid 8 with .sw at 0,0
"\fR\s10\&.\f1\s0" at 4,56
"\fR\s10\&.\f1\s0" at 4,40
"\fR\s10\&.\f1\s0" at 4,24
"\fR\s10\&\f1\s0" at 4,8
] |
define t833 |
[ box invis ht 96 wid 16 with .sw at 0,0
"\fR\s10\&M\f1\s0" at 8,88
"\fR\s10\&S\f1\s0" at 8,72
"\fR\s10\&G\f1\s0" at 8,56
"\fR\s10\&M\f1\s0" at 8,40
"\fR\s10\&N\f1\s0" at 8,24
"\fR\s10\&I\f1\s0" at 8,8
] |
define t829 |
[ box invis ht 64 wid 8 with .sw at 0,0
"\fR\s10\&.\f1\s0" at 4,56
"\fR\s10\&.\f1\s0" at 4,40
"\fR\s10\&.\f1\s0" at 4,24
"\fR\s10\&\f1\s0" at 4,8
] |
define t823 |
[ box invis ht 96 wid 40 with .sw at 0,0
"\fR\s10\&M\f1\s0" at 20,88
"\fR\s10\&S\f1\s0" at 20,72
"\fR\s10\&G\f1\s0" at 20,56
"\fR\s10\& S \f1\s0" at 20,40
"\fR\s10\&E\f1\s0" at 20,24
"\fR\s10\&G\f1\s0" at 20,8
] |
define t809 |
[ box invis ht 64 wid 8 with .sw at 0,0
"\fR\s10\&.\f1\s0" at 4,56
"\fR\s10\&.\f1\s0" at 4,40
"\fR\s10\&.\f1\s0" at 4,24
"\fR\s10\&\f1\s0" at 4,8
] |
define t800 |
[ box invis ht 192 wid 16 with .sw at 0,0
"\fR\s10\&M\f1\s0" at 8,184
"\fR\s10\&A\f1\s0" at 8,168
"\fR\s10\&P\f1\s0" at 8,152
"\fR\s10\&P\f1\s0" at 8,136
"\fR\s10\&E\f1\s0" at 8,120
"\fR\s10\&D\f1\s0" at 8,104
"\fR\s10\&\f1\s0" at 8,88
"\fR\s10\&S\f1\s0" at 8,72
"\fR\s10\&L\f1\s0" at 8,56
"\fR\s10\&O\f1\s0" at 8,40
"\fR\s10\&T\f1\s0" at 8,24
"\fR\s10\&S\f1\s0" at 8,8
] |
define m0 |
[ box invis ht 96 wid 32 with .sw at 0,0
line from 16,0 to 16,96
line from 0,0 to 32,0
] |
box invis ht 784 wid 512 with .sw at 0,0
t851 with .nw at 114,780
line from 464,688 to 464,648
line -> from 104,624 to 176,624
t850 with .nw at 11,645
box ht 72 wid 104 with .nw at 0,656
t849 with .nw at 456,634
t848 with .nw at 396,474
"\fR\s10\&struct msg\f1\s0" at 400,406
"\fR\s10\&struct msg\f1\s0" at 400,486
"\fR\s10\&struct msg\f1\s0" at 400,518
"\fR\s10\&struct msg\f1\s0" at 400,502
"\fR\s10\&struct msg\f1\s0" at 400,534
"\fR\s10\&struct msg\f1\s0" at 400,550
"\fR\s10\&struct msg\f1\s0" at 400,566
"\fR\s10\&struct msg\f1\s0" at 400,582
"\fR\s10\&struct msg\f1\s0" at 400,598
"\fR\s10\&struct msg\f1\s0" at 400,614
"\fR\s10\&struct msg\f1\s0" at 400,630
"\fR\s10\&struct msg\f1\s0" at 400,662
"\fR\s10\&struct msg\f1\s0" at 400,646
"\fR\s10\&struct msg\f1\s0" at 400,678
line from 360,416 to 440,416
line from 360,480 to 440,480
line from 360,496 to 440,496
line from 360,512 to 440,512
line from 360,528 to 440,528
line from 360,544 to 440,544
line from 360,560 to 440,560
line from 360,576 to 440,576
line from 360,592 to 440,592
line from 360,608 to 440,608
line from 360,624 to 440,624
line from 360,640 to 440,640
line from 360,656 to 440,656
line from 360,672 to 440,672
box ht 288 wid 80 with .nw at 360,688
line from 448,400 to 480,400
line from 448,688 to 480,688
t833 with .nw at 144,590
"\fR\s10\&struct msqid_ds\f1\s0" at 236,570
"\fR\s10\&struct msqid_ds\f1\s0" at 236,594
"\fR\s10\&struct msqid_ds\f1\s0" at 236,618
t829 with .nw at 232,506
box ht 264 wid 112 with .nw at 176,680
line from 176,440 to 288,440
line from 176,512 to 288,512
line from 176,536 to 288,536
line from 176,560 to 288,560
line from 176,584 to 288,584
line from 176,608 to 288,608
line from 176,632 to 288,632
line from 176,656 to 288,656
"\fR\s10\&struct msqid_ds\f1\s0" at 236,666
"\fR\s10\&struct msqid_ds\f1\s0" at 236,642
"\fR\s10\&struct msqid_ds\f1\s0" at 232,426
"\fR\s10\&struct msqid_ds\f1\s0" at 236,522
"\fR\s10\&struct msqid_ds\f1\s0" at 236,546
line from 136,416 to 168,416
line from 136,680 to 168,680
line from 152,416 to 152,488
line from 152,680 to 152,600
line from 296,320 to 296,280
line from 280,320 to 312,320
line from 296,0 to 296,64
line from 280,0 to 312,0
m0 with .nw at 136,96
line from 152,320 to 152,216
line from 136,320 to 168,320
t823 with .nw at 132,202
line from 176,344 to 192,344
line from 176,328 to 176,360
"\fR\s10\&MSGSSZ\f1\s0" at 224,342
line from 272,328 to 272,360
line from 272,344 to 256,344
line from 272,248 to 336,304 dotted
line from 336,248 to 496,248 dotted
box ht 240 wid 160 with .nw at 336,304
"\fR\s16\&1-8\f1\s0" at 372,273
"\fR\s12\&USED\f1\s0" at 444,273
"\fR\s16\&17-24\f1\s0" at 376,177
"\fR\s12\&USED\f1\s0" at 448,177
"\fR\s12\&USED\f1\s0" at 444,225
"\fR\s16\&9-16\f1\s0" at 376,225
"\fR\s16\&29-32\f1\s0" at 444,125
"\fR\s16\&25-28\f1\s0" at 376,125
"\fR\s12\&WASTED\f1\s0" at 452,89
"\fR\s12\&USED\f1\s0" at 376,89
line from 408,152 to 336,152 dotted
line from 408,152 to 408,64
line from 408,152 to 496,152
line from 336,200 to 496,200 dotted
"\fR\s12\&8\f1\s0" at 224,233
"\fR\s12\&8\f1\s0" at 224,305
t809 with .nw at 220,94
box ht 320 wid 96 with .nw at 176,320
line from 176,32 to 272,32
line from 176,104 to 272,104
line from 176,128 to 272,128
line from 176,152 to 272,152
line from 176,176 to 272,176
line from 176,200 to 272,200
line from 176,224 to 272,224
line from 176,248 to 272,248
line from 176,272 to 272,272
line from 176,296 to 272,296
"\fR\s12\&8\f1\s0" at 224,281
"\fR\s12\&8\f1\s0" at 224,257
"\fR\s12\&8\f1\s0" at 224,113
"\fR\s12\&8\f1\s0" at 224,13
"\fR\s12\&8\f1\s0" at 224,137
"\fR\s12\&8\f1\s0" at 224,161
"\fR\s12\&8\f1\s0" at 224,185
"\fR\s12\&8\f1\s0" at 224,209
line from 272,152 to 336,64 dotted
spline -> from 440,536\
to 512,536\
to 512,376\
to 120,376\
to 120,248\
to 176,248
spline -> from 360,536\
to 312,512\
to 360,488
spline -> from 360,584\
to 320,552\
to 360,536
spline -> from 360,632\
to 328,600\
to 360,584
line -> from 288,624 to 360,632
t800 with .nw at 288,262
"\fR\s10\&SLOT 7\f1\s0" at 532,110
"\fR\s10\&SLOT 6\f1\s0" at 532,178
"\fR\s10\&SLOT 5\f1\s0" at 532,222
"\fR\s10\&SLOT 4\f1\s0" at 532,274
line from 464,400 to 464,528
.PE
.fi
-----------------------------
From: Gilles Courcoux <gilles@pase60.convergent.com>
Subject: Re: nested loops
Date: 10 Aug 90 16:15:51 GMT
Sender: root@risky.convergent.com
To: unix-wizards@sem.brl.mil
In article <4103@herbie.misemi> you wrote:
>The problem lies in the $`echo $i` statment
Right, double variable expansion like that is resolved through the use
of the eval(1) command as in :
eval echo '$'$i
When the shell read the command, it expands it into
eval echo $them # the first time !
and then eval(1) do his job : evaluating its arguments, including
variables expansion and then execute the command which is by now :
echo one two three
The echo(1) command is needed because eval(1) then exec(2)utes its
first argument.
Your script become :
this="one two three"
that="four five six seven"
them="eight nine ten"
all="this that them"
#
for i in $all
do
for j in `eval echo '$'$i`
do
echo $i $j
done
done
Have a nice day,
Gilles Courcoux E-mail: sun!pyramid!ctnews!pase60!gilles
Unisys Network Computing Group Phone: (408) 435-7692
-----------------------------
From: Chris Bertin <chrisb@risky.convergent.com>
Subject: evaluating ${10} and above in sh/ksh
Keywords: sh, ksh, eval
Date: 10 Aug 90 17:58:37 GMT
To: unix-wizards@sem.brl.mil
There doesn't seem to be a way, in sh or ksh, to evaluate $10 and higher.
$10 and higher are evaluated as ${1}0, ${1}1, etc...
instead of ${10}, ${11}, etc...
I have tried many different ways and they all fail. Do you know one
that will work?
#! /bin/sh
set a b c d e f g h i j k l
arg=0
while [ $arg -le $# ]; do
echo "evaluating \$$arg"
eval echo $"$arg"
eval echo $"${arg}"
eval echo "$`eval echo $arg`"
# Now, some of the crazy things I tried.
# ( The parens are there when eval causes an error )
echo "\${$arg} results in \c"
( eval echo "\${$arg}" )
echo "$`echo '{'``eval echo $arg``echo '}'` results in \c"
( eval echo "$`echo '{'``eval echo $arg``echo '}'`" )
arg=`expr $arg + 1`
done
--
Chris Bertin | chrisb@risky.Convergent.COM
Unisys | or
(408) 435-3762 | ...!uunet!pyramid!ctnews!risky!chrisb
-----------------------------
From: "Jay A. Konigsberg" <jak@sactoh0.uucp>
Subject: Re: Getting CPU information on unterminatted child processes
Date: 11 Aug 90 09:43:04 GMT
To: unix-wizards@sem.brl.mil
In article <1990Aug7.215320.13715@mozart.amd.com> leight@mozart.amd.com (Timothy Leight) writes:
>I am interested in getting accurate cpu usage information
>on unterminated child processes. The getrusage() and/or times()
>system calls only return information on terminated children.
>
>What is the best method for getting this information?
>
Well, I don't know the best method, but I think I can point you in the
right direction (since no one else did).
ps -lf will provide much of the information needed, though it may not
produce enough and any way you invoke it (peopen or shell script), it
will be slow.
Another aproach is to get the information directly out of /dev/kmem.
However, all I know how to do there is get overall system usage
parameters. Specific information of /dev/kmem is probably system
specific and un-portable. However, the Sys V and Xenix 2.3.? header
file is: /usr/include/sys/sysinfo.h
Getting information about kernel level data structures on the net is
a little like asking for the moon, no one seems to have it. Anyway,
perhaps this post will generate a little discussion. I would like to
know more specifics about the Sys V kernel myself.
--
-------------------------------------------------------------
Jay @ SAC-UNIX, Sacramento, Ca. UUCP=...pacbell!sactoh0!jak
If something is worth doing, its worth doing correctly.
-----------------------------
From: Randal Schwartz <merlyn@iwarp.intel.com>
Subject: Re: Cron - First Saturday of the month
Date: 12 Aug 90 05:27:30 GMT
00.90Aug1014
Sender: news@iwarp.intel.com
To: unix-wizards@sem.brl.mil
In article <KPC00.90Aug10144909@JUTS.ccc.amdahl.com>, kpc00@JUTS (kpc) writes:
| Also, now that the OR is in there, which of merlyn's possibilities was
| correct? It makes one wonder what things, if any, are not possible in
| cron without putting something in the command to be executed.
Well, we already have one. The original request! (See Subject: :-)
Sigh.
--
/=Randal L. Schwartz, Stonehenge Consulting Services (503)777-0095 ==========\
| on contract to Intel's iWarp project, Beaverton, Oregon, USA, Sol III |
| merlyn@iwarp.intel.com ...!any-MX-mailer-like-uunet!iwarp.intel.com!merlyn |
\=Cute Quote: "Welcome to Portland, Oregon, home of the California Raisins!"=/
-----------------------------
End of UNIX-WIZARDS Digest
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----Transcript of message follows----
Date: 15 Aug 90 05:37:00 MDT
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#117
To: "math!ckaul" <math!ckaul@cs.sandia.gov>
Return-Path: <incoming-unix-wizards-request@sandia.gov>
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Date: Wed, 15 Aug 90 05:45:07 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#117
Message-ID: <9008150545.aa10597@SEM.BRL.MIL>
UNIX-WIZARDS Digest Wed, 15 Aug 1990 V10#117
Today's Topics:
CORRECTED CALL FOR VOTES: Reorganization of comp.unix.*
Archives of c.u.wizards
Re: evaluating ${10} and above in sh/ksh
Re: I_FDINSERT in streamio(4)
Repost: Can one driver call another directly?
Re: Interesting keyboard read problem (ioctl, function keys)
Re: cd failure killing script [Re: Interactive 2.2 File zapper]
Re: csh weirdness (HELP!)
sendmail config file question
Re: get terminal speed from shell script
Wanted: NQS software
Re: seeking information about file system details.
Re: Please add me to User list
directory "indexer"
Re: Getting CPU information on unterminatted child processes
Curses question
redirecting standard i/o from an exec'ed programme
-----------------------------------------------------------------
From: Chip Salzenberg <uunet!tct!chip@ncar.ucar.edu>
Subject: CORRECTED CALL FOR VOTES: Reorganization of comp.unix.*
Date: 5 Aug 90 21:41:11 GMT
Sender: lear@turbo.bio.net
Followup-To: news.groups
Approved: lear@turbo.bio.net
To: unix-wizards@sem.brl.mil
[ Document created: $Date: 90/07/27 18:31:22 $ ]
+----------------------------------------------------------+
| OOPS. |
| |
| I posted the original Call For Votes for the comp.unix.* |
| reorganization with an incorrect Reply-To: address. |
| There is no such domain as "pdn.com". |
| Please send votes to <chip%tct@pdn.paradyne.com>. |
| |
| Mea culpa, mea culpa, mea maxima culpa. |
+----------------------------------------------------------+
This article is a CALL FOR VOTES on a reorganization
of the comp.unix.* hierarchy. This reorganization
will add various "obvious" missing groups and rename
several groups which have misleading names.
PLEASE EXAMINE THE ENTIRE PROPOSAL BEFORE VOTING ON IT.
+----------+
| PROPOSAL |
+----------+
Create:
comp.unix.admin UNIX system administration.
comp.unix.msdos MS-DOS running under UNIX by whatever means.
comp.unix.large UNIX on mainframes and in large networks.
comp.unix.misc General discussions regarding UNIX.
comp.unix.programmer UNIX programming.
comp.unix.shell UNIX shell usage and programming.
comp.unix.xenix.sco XENIX versions from the Santa Cruz Operation. [*]
[*] NOTE: If comp.unix.xenix.sco passes, then comp.unix.xenix will be
renamed to comp.unix.xenix.misc, since its charter will have
changed to cover only non-SCO versions of XENIX. I didn't
want to make two changes based on one vote, but in this case
I think it's necessary. Experience teaches that parent
groups frequently draw inappropriate crossposting from their
children. Peer groups are better insulated from each other.
Rename:
comp.unix.microport -->
comp.unix.sysv286 UNIX System V (not XENIX) on the '286.
comp.unix.i386 -->
comp.unix.sysv386 UNIX System V (not XENIX) on the '386.
comp.unix.wizards -->
comp.unix.internals UNIX internals: kernel hacking, etc.
For completeness, here is a list of comp.unix groups for which NO change
is proposed:
comp.unix Discussion of UNIX* features and bugs. (Moderated)
comp.unix.aix IBM's version of UNIX.
comp.unix.aux The version of UNIX for Apple Macintosh II computers.
comp.unix.cray Cray computers and their operating systems.
comp.unix.questions Questions and answers about UNIX.
comp.unix.ultrix Discussion about DEC's Ultrix.
+---------------+
| VOTING METHOD |
+---------------+
Send votes to the mailbox "vote" on the machine "tct".
Possible ways to address votes include:
vote%tct@pdn.paradyne.com
vote@tct.uucp
uunet!pdn!tct!vote
Each vote must use this form:
======== START VOTING FORM =========
admin yes/no/abstain
msdos yes/no/abstain
large yes/no/abstain
misc yes/no/abstain
programmer yes/no/abstain
shell yes/no/abstain
xenix.sco yes/no/abstain
sysv286 yes/no/abstain
sysv386 yes/no/abstain
internals yes/no/abstain
======== END VOTING FORM =========
A valid vote MUST specify either "yes", "no" or
"abstain" for EACH proposed change. Each proposed
newsgroup creation or renaming will stand on its own.
Extra verbiage and/or quoting characters will be
ignored, so don't panic if you send a vote with ">"
characters still in place.
I will use a Perl script to tabulate well-formed
votes. If a badly-formed vote is complete and its
meaning is obvious, I will fix it. Otherwise, I will
reply to the voter with a form message that explains
how to cast a valid vote -- essentially, another copy
of this article.
+----------+
| SCHEDULE |
+----------+
1. Voting:
The vote will run for 21 days from the time the
Call For Votes appears in news.announce.newgroups,
or until Sunday, August 18, whichever is longer.
I will post a second Call For Votes, and possibly
a list of unreachable return addresses, during the
voting period. When the vote is over, I will post
the final results.
2. Waiting Period:
I will observe the normal waiting period of five
days from the time that the final results appear
in news.announce.newgroups. During this time,
people may report lost votes and/or impugn the
fairness of the vote taker. :-)
3. Consummation:
After the waiting period, I will issue the
appropriate control messages to create all new
groups and/or new names for renamed groups. About
one week later, I will re-issue the creation
control messages, and also issue removal control
messages for old names of renamed groups.
If all goes as planned, whatever parts of the
reorganization that pass will take effect by the end
of August.
--
Chip Salzenberg at ComDev/TCT <chip@tct.uucp>, <uunet!ateng!tct!chip>
-----------------------------
From: Joe Ammond <KITBASH@mtus5.bitnet>
Subject: Archives of c.u.wizards
Date: 13 Aug 90 16:03:20 GMT
To: unix-wizards@sem.brl.mil
Apollogies if this is a FAQ or RTFM(news) question, but, is there an archive of
comp.unix.wizards anywhere, for uucp or ftp (ftp preferred)? I'd rather read
the old questions & answers than posting my own problems if they've already
been solved.
++thanks,
ja.
Joe Ammond Computer Consultant, Mich. Tech. Univ.
Summer Programmer, Ford Motor Co.
-----------------------------
From: Robert Hartman <hartman@ide.com>
Subject: Re: evaluating ${10} and above in sh/ksh
Keywords: sh, ksh, eval
Date: 13 Aug 90 16:35:32 GMT
Sender: Bert Beaton <bert@ide.com>
To: unix-wizards@sem.brl.mil
In article <514@risky.Convergent.COM> chrisb@risky.Convergent.COM (Chris Bertin) writes:
>There doesn't seem to be a way, in sh or ksh, to evaluate $10 and higher.
>$10 and higher are evaluated as ${1}0, ${1}1, etc...
> instead of ${10}, ${11}, etc...
>I have tried many different ways and they all fail. Do you know one
>that will work?
>
This is what the shift builtin is for:
# sort out arguments
while [ $# -gt 0 ] ; do
case $1 in
-a) a=true ;;
-b) b=true ;;
-*) "echo illegal option" ;;
*) "$files $i" ;;
esac
shift
done
This will process through all of your arguments and build a list of filenames.
It doesn't work if options can have arguments of their own. For cases like
this, I use getopts to parse out the command line. There's a good example in
the getopts man page.
-r
-----------------------------
From: "Gordon C. Galligher" <gorpong@ping.uucp>
Subject: Re: evaluating ${10} and above in sh/ksh
Keywords: sh, ksh, eval
Date: 14 Aug 90 03:36:14 GMT
To: unix-wizards@sem.brl.mil
In article <514@risky.Convergent.COM> chrisb@risky.Convergent.COM
(Chris Bertin) writes:
>There doesn't seem to be a way, in sh or ksh, to evaluate $10 and higher.
>$10 and higher are evaluated as ${1}0, ${1}1, etc...
> instead of ${10}, ${11}, etc...
>I have tried many different ways and they all fail. Do you know one
>that will work?
I realize this is hardly what you wish to read, but the only way to gain
access to the others is by using 'shift' to get them. You could, on the
other hand set up a loop to grab all of them into your own variables:
argv0=$0
start=1
pred=argv
for i
do
eval "${pred}${start}='$i'" # Be sure to quote the $i !!
start=`expr $start + 1`
done
argc=`expr $start - 1`
This would give you variables $argv0, $argv1, $argv2 up to and including
$argv$argc. To simply print them out:
echo " 0 - $argv0"
start=1
while [ $start -le $argc ]
do
echo " $start - `eval echo '$'${pred}${start}`" # Yes, ugly
start=`expr $start + 1`
done
No, it is not pretty, but it is workable. There may not be many times you
would want to print option 'x' without knowing what 'x' was. If you
always wanted to check the first option, then it is just $argv1. If you
find yourself always parsing through the command line options, then you
should probably put a case inside of the for and then do with them what
you will.
-- Gordon.
--
Gordon C. Galligher 9127 Potter Rd. #2E Des. Plaines, Ill. 60016
telxon!ping%gorpong@uunet.uu.net (not tested) (Is this even legal??)
...!uunet!telxon!ping!gorpong (tested) (And it works!)
"It seems to me, Golan, that the advance of civilization is nothing but an
-----------------------------
From: "stephen.a.rago" <sar0@cbnewsl.att.com>
Subject: Re: I_FDINSERT in streamio(4)
Date: 13 Aug 90 17:20:58 GMT
To: unix-wizards@sem.brl.mil
In article <WS.90Aug9184533@karl.tools.uucp>, ws@tools.uucp (Wolfgang Solfrank) writes:
> Currently I'm trying to write a trace module and/or driver for
> streams tracing. I need it for easier testing and debugging of
> a streams protocol stack we are developping here. I'd like to
> let the traced driver/modules and the application as much alone
> as possible. So I face the problem of duplicating all messages
> that are sent thru the protocol stack to the trace application.
>
> How do I tell the trace driver what streams stack to intercept?
Make the trace driver both a module and a driver, and push it on
the stream in the place you'd like to debug. Use the module to log
messages and use the driver to recover them.
Steve Rago
sar@attunix.att.com
-----------------------------
From: Doug Toppin <toppin@melpar.uucp>
Subject: Repost: Can one driver call another directly?
Keywords: driver, motorola
Date: 13 Aug 90 19:54:57 GMT
To: unix-wizards@sem.brl.mil
Is it possible for a device driver to call another device driver directly?
I have the following problem:
I need to send a command to a serial device in less than 100 milliseconds
of receiving data from a custom device.
I would like to have my custom driver call the serial driver directly
and pass it the data to send.
Is it possible to call an entry point of the serial driver directly
from another driver?
In the past I have done something similar on a different operating system
by putting data into the clist and calling the line discipline entry
point of the serial driver.
I would like a more direct (and documented) means of doing this.
Here are the specifics:
* I am using Motorola Unix R3V5 on the MVME-147A (68030)
* serial card is the MVME-332XT device, 19.2K rate
* I cannot afford overhead of bubbling up to an application and back down
Please respond by mail or post.
thanks
Doug Toppin
uunet!melpar!toppin
-----------------------------
From: Leslie Mikesell <les@chinet.chi.il.us>
Subject: Re: Interesting keyboard read problem (ioctl, function keys)
Date: 13 Aug 90 21:10:07 GMT
To: unix-wizards@sem.brl.mil
In article <7562@ucdavis.ucdavis.edu> tuck@iris.ucdavis.edu (Devon Tuck) writes:
>I have been working with an intersting problem... How to write a keyboard
>input routine that does not mess up its' transmission of repeated function
>keys. You might have noticed that even in vi, and in the C-shell, if you
>sit on an arrow key or some other function key that maps to a character
>sequence, you get intermittent beeps, or stray characters, respectively.
>The problem is that this editor is very bulky, and spends too much time
>away from the keyboard input routine, so that if I do the logical thing
>and set VMIN=1 and VTIME=0, portions of the home key sequence (<ESC>[H),
>for example, get split across network packets and arrive with too much gap
>for the keyboard driver to consider it a valid screen movement sequence.
Doesn't look logical to me. How about setting VMIN=1, VTIME=2 and make
your read()'s request many characters at once in order to always catch
up with the keyboard in one syscall?
>Has anyone solved this problem? I think I might have it with a routine that
>forks on its' first call, after setting up a pipe and ioctl calls, (VMIN=0,
>VTIME=0) and thus leaves a small subprocess running alongside the editor
>acting as a slave to the keyboard and sending all characters into a pipe
>to be read at the leasure of the main character input routine.
This is a reasonable approach but shouldn't really be necessary unless you
are waiting for slow operations like a screen redraw to complete before
checking for keyboard input. You certainly wouldn't want to set VMIN=0
though, or you will be making hundreds of syscalls/second and consume most
of the CPU. A subprocess would want to block when there is no input since
it would have nothing else to do. An alternative would be to make your
output routine check for input every so often. A little math involving
chars/sec. should generate a suitable number to catch all the input
without swamping the machine. (Use ioctl() to set O_NDELAY temporarily
so you can do a non-blocking read into a buffer).
>How do other editors do it? How do Crisp, emacs, etc. handle this? (as I
>mentioned, vi doesn't..)
If you don't use a bare "escape" as a command, there is no need to do any
funny timing to detect escape sequences. If you do need the timing, the
best approach under sysV would be to let the driver do it by setting
VTIME appropriately (and you will still probably miss once in a while).
Les Mikesell
les@chinet.chi.il.us
-----------------------------
From: Leslie Mikesell <les@chinet.chi.il.us>
Subject: Re: cd failure killing script [Re: Interactive 2.2 File zapper]
Date: 13 Aug 90 21:17:16 GMT
To: unix-wizards@sem.brl.mil
In article <9118@jpl-devvax.JPL.NASA.GOV> lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall) writes:
>In article <26C2F1A0.205B@tct.uucp> chip@tct.uucp (Chip Salzenberg) writes:
>: According to davidsen@sixhub.UUCP (bill davidsen):
>: >Yes, only ksh gives you the choice of catching the failure.
>:
>: Bash 1.05 also continues after a "cd" failure.
>Likewise Perl. The idiom to catch the failure is
> chdir $dir || die "Can't cd to $dir: $!\n";
This is reasonable behaviour for perl since it doesn't claim any
compatibility with /bin/sh scripts. Those other two mentioned above
will cause serious problems when executing scripts that are
perfectly valid for /bin/sh. They could (should) have required a "set"
option to be done to make them operate differently.
Les Mikesell
les@chinet.chi.il.us
-----------------------------
From: Matt Cross <mcross@pennies.sw.stratus.com>
Subject: Re: csh weirdness (HELP!)
Date: 13 Aug 90 21:52:32 GMT
Sender: usenet@lectroid.sw.stratus.com
To: unix-wizards@sem.brl.mil
In article <1990Aug13.151415.14575@elroy.jpl.nasa.gov>,
alan@cogswell.Jpl.Nasa.Gov (Alan S. Mazer) writes:
|>Someone came to me with the following problem and I'm clueless.
|>If I type (SunOS 4.0.3)
|>
|> kill `ps | grep a.out | awk '{printf("%d ",$1);}'`
|>
|>to kill every instance of a.out I get
|>
|> `ps | grep a.out | awk '{printf("%d ",$1);}'`: Ambiguous.
|>
|>Any idea why? It's not the $1 (changing that doesn't affect anything), and
|>it works if the command is in a shell script, or if instead of kill one uses
|>/bin/kill. It also works great inside the Bourne shell. Using echo instead
|>of kill produces the expected string of space-separated pid's.
|>
Are you using the shell built-in kill? That would explain the difference.
When I tried it a sun here, it said:
kill: Arguments should be jobs or process id's.
But, I'm using tcsh. It seems to me that the internal commands handle the
backquotes differently... That's as much as I could figure out...
--
These are my views, and in no way reflect the views of Stratus Computer, Inc.
Mail to: mcross@es.stratus.com or profesor@wpi.wpi.edu
-----------------------------
From: davy@intrepid.itstd.sri.com
Subject: sendmail config file question
Date: 13 Aug 90 23:46:54 GMT
Sender: davy@sparkyfs.istc.sri.com
To: unix-wizards@sem.brl.mil
We're getting ready to change our domain name, and I want to make sendmail
clever enough to handle mapping the old domain to the new one. Problem is,
we're already doing that from the domain name of about a year ago.
Basically, right now I have:
DDitstd.sri.com current domain name
DEistc.sri.com old domain name
S1
R$*<@$-.$E>$* $1<@$2.$D>$3 change domain name
R$*<@$E>$* $1<@$D>$2 change domain name
and likewise for S2. Now, to handle both old domain names, I figured I
could use a class:
DDerg.sri.com new domain name
CDistc.sri.com itstd.sri.com old domain names
S1
R$*<@$-.$=D>$* $1<@$2.$D>$3 change domain name
R$*<@$=D>$* $1<@$D>$2 change domain name
and likewise for S2.
But this doesn't work; the matches against the class fail. Reading the
sendmail manual, it mentions something about "token" being the unit of
a class. I'm assuming the match is failing because "istc.sri.com" and
"itstd.sri.com" are three tokens each rather than one.
Is this right? If so, is there a way to do what I want with classes?
Thanks,
Dave Curry
SRI International
-----------------------------
From: George Turczynski <george@hls0.hls.oz>
Subject: Re: get terminal speed from shell script
Date: 14 Aug 90 00:36:45 GMT
To: unix-wizards@sem.brl.mil
On SunOS 4.0.3 (and probably the rest too), if you have installed
/usr/5bin then use:
speed=`/usr/5bin/stty speed`
in your shell scripts. This works.
By the way, the SUN manuals point out quite clearly that
"the settings are reported on the standard error."
for /bin/stty, and
"the settings are reported on the standard output"
for /usr/5bin/stty.
Be sure to re-read the manual to check that the different versions
apply to the device you want. ie /bin/stty sets/reports the stdout device,
whilst /usr/5bin/stty sets/reports the stdin device.
Hope this is of some use to you...
--
| George P. J. Turczynski. |----------------------------------------------------
| Computer Systems Engineer. | ACSnet: george@highland.oz | I can't speak for the |
| Highland Logic Pty. Ltd. | Phone: +61 48 683490 | company, I can barely |
| Suite 1, 348-354 Argyle St | Fax: +61 48 683474 | speak for myself... |
| Moss Vale. NSW. Australia. 2577 |----------------------------------------------------
-----------------------------
From: Bob McGowen x4312 dept208 <bob@wyse.wyse.com>
Subject: Re: get terminal speed from shell script
Date: 14 Aug 90 01:21:24 GMT
Sender: news@wyse.wyse.com
Followup-To: comp.unix.questions
To: unix-wizards@sem.brl.mil
In article <90Aug12.135618edt.18763@me.utoronto.ca> sun@hammer.me.UUCP (Andy Sun Anu-guest) writes:
>Hi Net,
>
>The question I have is:
>
>Is there a way to get the terminal speed from a (sh or csh) script?
>
>I used to be able to do the following in a Bourne shell script:
>
> speed=`stty speed`
>
>and got the terminal speed assigned to variable speed. As various OS
>gets updated (e.g. Ultrix 3.1 and SUN OS 4.0.3), this won't work anymore
>because all stty outputs are being sent to stderr, not stdout, thus no
>piping or redirection is possible. Is there any similar commands that can
You CAN still cause redirection to occur.
>get terminal speed inside a shell script?
I just tried the following:
date>date.data
echo 'echo date.data >&2 # sends file name to standard error' > errout
chmod +x errout
cat `errout` # date.data appeared on screen, cat read terminal
# this is the expected result
cat `errout 2>&1` # the date stored in the file was cat'ed to the screen
Of course, this is the Bourne shell, not csh. I cannot vouch for how or if
this is possible with csh.
Bob McGowan (standard disclaimer, these are my own ...)
Product Support, Wyse Technology, San Jose, CA
..!uunet!wyse!bob
bob@wyse.com
-----------------------------
From: Gerry Roderick Singleton <gerry@jts.com>
Subject: Re: get terminal speed from shell script
Date: 14 Aug 90 18:10:10 GMT
To: unix-wizards@sem.brl.mil
In article <90Aug13.095129edt.18647@me.utoronto.ca> sun@me.utoronto.ca (Andy Sun Anu-guest) writes:
>In article <1990Aug13.005849.23223@jarvis.csri.toronto.edu> ruhtra@turing.toronto.edu (Arthur Tateishi) writes:
>>In artcle <90Aug12.135618edt.18763@me.utoronto.ca> sun@me.utoronto.ca (Andy Sun Anu-guest) writes:
>>
>>>Is there a way to get the terminal speed from a (sh or csh) script?
>>>I used to be able to do the following in a Bourne shell script:
>>> speed=`stty speed`
[lines deleted]
>
>I guess it depends on which version of SUN OS. "speed=`stty speed`" works
>for a Sun 3/60 running (I think) SUN OS 3.x. So it does went through stdout.
[more lines deleted]
>>other than a proper tty device, I came up with the following.
>> speed=`stty speed 3>&2 2>&1 1>&3`
[more lines deleted]
I like to add my two penny's worth, to query the speed of the tty device
shouldn't one accept input from the device rather than perform output
to it before getting the answer? The question is rhetorcal so don't bother
answering it. It apppears to me to be valid in this case for BSD4.3 running
on an ISIv24. Here's my little sample:
#! /bin/sh
speed=`stty speed </dev/tty 2>&1`
echo $speed
and the results:
/usr/local/src >%[530] sh -vx foo
#! /bin/sh
speed=`stty speed </dev/tty 2>&1`
+ stty speed
speed=9600
echo $speed
+ echo 9600
9600
/usr/local/src >%[531]
I believe this satisfies Andy's requirements and I hope it's what he wanted.
Anyways it'll fuel the discussion.
Cheers,
ger
--
--
G. Roderick Singleton, System and Network Administrator, JTS Computers
{uunet | geac | torsqnt}!gerry@jtsv16.jts.com
-----------------------------
From: "BURNS,JIM" <gt0178a@prism.gatech.edu>
Subject: Re: get terminal speed from shell script
Date: 15 Aug 90 05:42:34 GMT
Followup-To: comp.unix.questions
To: unix-wizards@sem.brl.mil
in article <1990Aug14.181010.29571@jts.com>, gerry@jts.com (Gerry Roderick Singleton ) says:
> #! /bin/sh
>
> speed=`stty speed </dev/tty 2>&1`
> echo $speed
Nope, on SunOS 4.0, you get:
{richsun12:/usr}
[196] t=`stty speed </dev/tty 2>&1`
{richsun12:/usr}
[197] echo $t
stty: Operation not supported on socket
{richsun12:/usr}
[198]
--
BURNS,JIM
Georgia Institute of Technology, Box 30178, Atlanta Georgia, 30332
uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!gt0178a
Internet: gt0178a@prism.gatech.edu
-----------------------------
From: Roy Laor <roy@taux01.nsc.com>
Subject: Wanted: NQS software
Date: 14 Aug 90 08:50:21 GMT
To: unix-wizards@sem.brl.mil
I am interested in NQS (Network Queuing System) for submitting jobs on
a UNIX system. I have heard that it's a public domain. Does anybody know
where can I get these sources from ?
Thanks,
Roy roy@taux01.nsc.com
-----------------------------
From: Richard Tobin <richard@aiai.ed.ac.uk>
Subject: Re: seeking information about file system details.
Date: 14 Aug 90 11:36:24 GMT
To: unix-wizards@sem.brl.mil
In article <28595@athertn.Atherton.COM> mcgregor@hemlock.Atherton.COM (Scott McGregor) writes:
>I guess what I am interested in is if I have a non-unix file system
>and I want to allow the this file system to be mounted as a unix
>file system, and accessed using open, creat, read, write, close, et al,
If your system already has NFS, you can do this without kernel
modifications, by writing an NFS server for your device. NFS mounting
works by passing the kernel the address of a socket through which it
can send and receive messages from the filesystem. I recently hacked
up such a thing so that I can mount Minix floopies on a Sun.
I can send you the code if you're interested.
-- Richard
--
Richard Tobin, JANET: R.Tobin@uk.ac.ed
AI Applications Institute, ARPA: R.Tobin%uk.ac.ed@nsfnet-relay.ac.uk
Edinburgh University. UUCP: ...!ukc!ed.ac.uk!R.Tobin
-----------------------------
From: Don Lewis <del@thrush.mlb.semi.harris.com>
Subject: Re: seeking information about file system details.
Date: 15 Aug 90 05:40:05 GMT
Sender: news@mlb.semi.harris.com
To: unix-wizards@sem.brl.mil
In article <3199@skye.ed.ac.uk> richard@aiai.UUCP (Richard Tobin) writes:
>In article <28595@athertn.Atherton.COM> mcgregor@hemlock.Atherton.COM (Scott McGregor) writes:
>>I guess what I am interested in is if I have a non-unix file system
>>and I want to allow the this file system to be mounted as a unix
>>file system, and accessed using open, creat, read, write, close, et al,
>
>If your system already has NFS, you can do this without kernel
>modifications, by writing an NFS server for your device. NFS mounting
>works by passing the kernel the address of a socket through which it
>can send and receive messages from the filesystem. I recently hacked
>up such a thing so that I can mount Minix floopies on a Sun.
>
>I can send you the code if you're interested.
I did this for an automatic version of /usr/hosts. It periodically
reads the hosts YP map and emulates a directory of symbolic links
to /usr/ucb/rsh for the map entries.
I have another application in mind where I would like to build
my own filesystem type. It would not be a complete filesystem
implementation. The reason that I can't do it with an NFS server
is that I need to know what syscall a process is executing when
the process is doing a lookup in my filesystem.
--
Don "Truck" Lewis Harris Semiconductor
Internet: del@mlb.semi.harris.com PO Box 883 MS 62A-028
Phone: (407) 729-5205 Melbourne, FL 32901
-----------------------------
From: Grant Grundler <grant@pescara.orc.olivetti.com>
Subject: Re: Please add me to User list
Date: 14 Aug 90 17:19:18 GMT
Sender: news@orc.olivetti.com
To: unix-wizards@sem.brl.mil
In article <24129@adm.BRL.MIL>, genesis@BRL.MIL (MAJ. Kindel) writes:
> Please add me to your user list. I am with the US Army
> Computer Science School.
>
> Thank You
> Info Center
> USA Computer Science School
> AV 780-3245 COMM(404)791-3245
Looks like the somebody needs to learn how to use "rn"!
grant
-----------------------------
From: Saumen K Dutta <skdutta@CSSUN.TAMU.EDU>
Subject: Re: Please add me to User list
Date: 14 Aug 90 22:45:43 GMT
Sender: usenet@TAMU.EDU
To: unix-wizards@sem.brl.mil
From: grant@Pescara.ORC.Olivetti.Com (Grant Grundler)
Subject: Re: Please add me to User list
Message-ID: <49280@ricerca.UUCP>
Date: 14 Aug 90 17:19:18 GMT
References: <24129@adm.BRL.MIL>
Sender: news@orc.Olivetti.Com
Reply-To: grant@Pescara.ORC.Olivetti.Com (Grant Grundler)
Organization: Olivetti Research California
Lines: 13
In article <49280@ricerca.UUCP>, grant@Pescara.ORC.Olivetti.Com
(Grant Grundler) writes:
:In article <24129@adm.BRL.MIL>, genesis@BRL.MIL (MAJ. Kindel) writes:
:> Please add me to your user list. I am with the US Army
:> Computer Science School.
:>
:> Thank You
:> Info Center
:> USA Computer Science School
:> AV 780-3245 COMM(404)791-3245
:
:
:Looks like the somebody needs to learn how to use "rn"!
:
:grant
:
Or is there any mailing list which simultaneouly post the
news to various addresses. In any case why flaming new
users ?
--
_ ||Internet: skdutta@cssun.tamu.edu
( /_ _ / --/-/- _ ||Bitnet : skd8107@tamvenus.bitnet
__)_/(_____(_/_(_/_(_(__(_/_______ ||Uucp : uunet!cssun.tamu.edu!skdutta
.. ||Yellnet: (409) 846-8803
-----------------------------
From: Keith Gabryelski <ag@cbmvax.commodore.com>
Subject: Re: Please add me to User list
Date: 14 Aug 90 22:56:05 GMT
To: unix-wizards@sem.brl.mil
In article <49280@ricerca.UUCP> grant@Pescara.ORC.Olivetti.Com (Grant Grundler) writes:
>In article <24129@adm.BRL.MIL>, genesis@BRL.MIL (MAJ. Kindel) writes:
>> Please add me to your user list. I am with the US Army
>> Computer Science School.
>>
>> Thank You
>> Info Center
>> USA Computer Science School
>> AV 780-3245 COMM(404)791-3245
>
>
>Looks like the somebody needs to learn how to use "rn"!
A lot of people read news as if it came from a mailing list (Ie, they
send their mail address to a list keeper and use their mail reader to
read all incoming mail). Inefficient, but workable for a small number
of groups. This Kindel guy is probably one of them.
Pax, Keith
-----------------------------
From: Ted Persky <tpersky@suntory.dcrt.nih.gov>
Subject: directory "indexer"
Keywords: search,directory,index
Date: 14 Aug 90 15:16:23 GMT
Sender: news@nih-csl.nih.gov
Followup-To: comp.unix.questions
To: unix-wizards@sem.brl.mil
It has come to my attention that our staff on the whole spends
a great deal of time during the day searching for that one
certain file in a large directory tree. For example, try finding
a certain fragment of source code in the X11 distribution.
The people in our lab always seem to be asking each other
to help them locate the path name for "foo.c".
What I'm wondering is whether anyone knows of a tool where
one can define a directory as being the root of a "large file
tree" and have an index of some sort placed at that root. After
that is created, each person who creates a file in that particular
sub-tree would type in some sort of librarian command to create
an entry in the index with a brief description of the file.
Then the index (in database form, preferably) could be queried
to locate the path name for a desired file. This would be ideal
if people such as MIT could create this for their distributions
of X, or UNIX vendors for their source distributions.
If you could send me e-mail concerning this, I'd greatly appreciate
it.
Thanx,
Ted Persky phone: (301) 496-2963
Building 12A, Room 2031 Internet: tpersky@alw.nih.gov
National Institutes of Health
Bethesda, MD 20892
-----------------------------
From: Grant Grundler <grant@pescara.orc.olivetti.com>
Subject: Re: Getting CPU information on unterminatted child processes
Date: 14 Aug 90 16:56:55 GMT
Sender: news@orc.olivetti.com
To: unix-wizards@sem.brl.mil
System Vr4 has a /proc file system which allows the average user to
read process memory space as if it where a file. The user must normally
have access to the process. On sysV4, ps also gets the info from here.
On older systems I would also use "ps" as suggested by jak@sactoh0.UUCP.
grant
-----------------------------
From: Keith Gabryelski <ag@cbmvax.commodore.com>
Subject: Re: Getting CPU information on unterminatted child processes
Date: 14 Aug 90 21:48:01 GMT
To: unix-wizards@sem.brl.mil
In article <3699@sactoh0.UUCP> jak@sactoh0.UUCP (Jay A. Konigsberg) writes:
>In article <3879@auspex.auspex.com> guy@auspex.auspex.com (Guy Harris) writes:
>>>Getting information about kernel level data structures on the net is
>>>a little like asking for the moon, no one seems to have it.
>>
>>No, it's more like asking for the moon if you're on Jupiter; the
>>appropriate response is "which moon"? Kernel-level data structures
>>differ between different UNIX implementations.
>
>This is true, however, the number of Sys V/Xenix and BSD/Sun systems
>out there cover the majority of systems.
I would say not. For instance, getting the user structure for a
certain process is different depending the version of Xenix you are
running (2.1 or 3.2) and what machine you are running on (286 or
386).
Some Unix Systems use a system call to find such information; 3b2 use
sys3b(); 3b1 use syslocal().
System V Release 4.0 does the /proc thing.
That is six different ways (no Xenix 3.2/286) of handling the same
operation under systems you would group under SysV/Xenix; Ackphfffftt!
Guy is correct--``Which moon'' is the response you should expect if you
ask about kernel specifics without giving any detail about the target
system.
Pax, Keith
-----------------------------
From: Glenn Pitcher <gpitcher@edpmgt.uucp>
Subject: Curses question
Keywords: key interpretation problems
Date: 14 Aug 90 17:23:52 GMT
To: unix-wizards@sem.brl.mil
(editor's note: This may be a duplicate transmision. Sorry if you got it
twice)
I'm attempting to write my first curses program and have already run into
a couple of problems.
The first one involves interpretation of input keys. How can one tell the
difference between the forward and backward tabs?? When I run my test
program, I get 0x09 for both. In addition, the code I'm getting in my
test program for a return is different that the code which is returned in
the real program (0x0a vs. 0x0d) and yes, these two programs are being run
on the same system.
Sooo, could some curses guru out there possibly tell me what's going on???
Thanks,
--
Glenn Pitcher UUCP: {crash,ucsd}!edpmgt!gpitcher
Programmer/Analyst & hp-sdd!teamnet!gpitcher
Unix Guru in training
EDP Management, Inc. * Proud member of Team.Net *
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
-----------------------------
From: Michael Katzmann <michael@fe2o3.uucp>
Subject: redirecting standard i/o from an exec'ed programme
Keywords: popen, io, exec, system
Date: 14 Aug 90 17:45:05 GMT
Followup-To: comp.unix.questions
To: unix-wizards@sem.brl.mil
I have a task that requires the ability to fork off another programme but
to supply it's standard input and output. The SysV manuals describe
FILE *popen( command, type )
char *command, *type;
which execs the command a la "system()" and creates a pipe. "type" and be
"r" if you want to read from the standard output of "command", or "w" if
you want to write to standard input. However there doesn't seem to be any
way to use this routine to do both similtaneously.
What is the usual way to to this?
Important points: The exec'ed command must run asynchronously (obvious if
the parent is supplying input.)
The child process id must be available to the parent.
(so that it can be killed if necessary)
Any ideas would be appreciated.
---------------------------------------------------------------------
email to
UUCP: uunet!mimsy!{arinc,fe2o3}!vk2bea!michael
_ _ _ _
Amateur | VK2BEA (Australia) ' ) ) ) / //
Radio | G4NYV (United Kingdom) / / / o _. /_ __. _ //
Stations| NV3Z (United States) / ' (_<_(__/ /_(_/|_</_</_
Michael Katzmann
Broadcast Sports Technology.
2135 Espey Ct. #4
Crofton Md. 21114 USA
Ph: +1 301 721 5151
-----------------------------
End of UNIX-WIZARDS Digest
**************************postmaster@sandia.gov (SMTP MAILER) (08/19/90)
----Reason for mail failure follows----
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----Transcript of message follows----
Date: 16 Aug 90 05:36:00 MDT
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#118
To: "math!ckaul" <math!ckaul@cs.sandia.gov>
Return-Path: <incoming-unix-wizards-request@sandia.gov>
Received: from SEM.BRL.MIL by sandia.gov with SMTP ;
Thu, 16 Aug 90 05:22:53 MDT
Received: from SEM.BRL.MIL by SEM.BRL.MIL id aa21242; 16 Aug 90 5:57 EDT
Received: from sem.brl.mil by SEM.BRL.MIL id aa21187; 16 Aug 90 5:45 EDT
Date: Thu, 16 Aug 90 05:45:08 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#118
Message-ID: <9008160545.aa21187@SEM.BRL.MIL>
UNIX-WIZARDS Digest Thu, 16 Aug 1990 V10#118
Today's Topics:
Re: evaluating ${10} and above in sh/ksh
Re: csh weirdness (HELP!)
Re: waitpid() ???
Re: Cron - First Saturday of the month
Re: Please add me to User list
AT&T 3B2, PC-NFS, Curses - reverse video with werase()
Re: sendmail config file question
Re: Is HDB locking safe?
Broadcast UDP packets
shmat() system call?
Re: shmat() system call?
Re: Curses question
Re: Another "why won't this work" program
How to restrict commands in rsh?
Vi fails on a Sun-4
Directory compression
-----------------------------------------------------------------
From: Bob Desinger <bd@hpopd.hp.com>
Subject: Re: evaluating ${10} and above in sh/ksh
Date: 14 Aug 90 15:35:15 GMT
To: unix-wizards@sem.brl.mil
> There doesn't seem to be a way, in sh or ksh, to evaluate $10 and higher.
In /bin/sh this never worked, although individual vendors may have
modified their /bin/sh. I don't know of any that have, by the way.
It looks like your ksh is broken. Version 06/03/86 (or at least that
version shipped with HP-UX at 7.0 on Series 300 and 800) does the
right thing:
set a b c d e f g h i j k l
print 9 is $9, 10 is ${10}, 11 is ${11}, 12 is ${12}.
alias i='echo Number 9'
alias j='echo Number 10'
alias k='echo Number 11'
alias l='echo Number 12'
eval $9
eval ${10}
eval ${11}
eval ${12}
The new ksh88, Version 11/16/88, also does the right thing. Both
versions of ksh generate the correct output:
9 is i, 10 is j, 11 is k, 12 is l.
Number 9
Number 10
Number 11
Number 12
I invoked the script with `ksh script' and `ksh88 script'. Then I
also tested it with a first line of `#! /usr/local/bin/ksh88' and
`#! /bin/ksh'. All four cases generated the same output. Uh, ksh88
isn't shipped with HP-UX; we bought it from the AT&T Toolchest.
Your script lines are considerably more complex than mine, though. In
fact, I stopped trying to figure out what the script was trying to do
and just ran your script. I mailed my output to you; we can follow
this up offline. Summarize to the net?
-- bd
-----------------------------
From: Bob Desinger <bd@hpopd.hp.com>
Subject: Re: csh weirdness (HELP!)
Date: 14 Aug 90 15:49:12 GMT
To: unix-wizards@sem.brl.mil
> to kill every instance of a.out I get
> `ps | grep a.out | awk '{printf("%d ",$1);}'`: Ambiguous.
Can you work around this by changing the awk program to generate the
kill commands, then piping the awk output to the shell? As in:
ps | grep a.out | awk '{print "kill", $1}' | sh
-- bd
-----------------------------
From: Dave Decot <decot@hpisod2.cup.hp.com>
Subject: Re: waitpid() ???
Date: 15 Aug 90 00:26:26 GMT
To: unix-wizards@sem.brl.mil
> >Does anyone have an idea exactly what [waitpid()] does?
>
> waitpid() is a POSIX function:
>
> int waitpid(int pid, int *status, int options)
>
> where the `pid' argument is the process ID of the process to wait
> for, or WAIT_ANY to wait for any child;
WAIT_ANY does not exist in POSIX. The correct value to wait for any child
is -1.
Dave Decot
-----------------------------
From: Steve Alter <alter@ttidca.tti.com>
Subject: Re: Cron - First Saturday of the month
Date: 15 Aug 90 01:46:48 GMT
To: unix-wizards@sem.brl.mil
In article <19744@orstcs.CS.ORST.EDU> curt@oce.orst.edu (Curt Vandetta) writes:
} I'm wondering if anyone has a way of making cron run a job on the
} first Saturday of every month?
I'm going to totally side-step the fight that has been waged over
whether the day-of-week is logically ANDed or ORed with the day-of-month.
You can set it up using a combination of cron and "at".
For example, let's assume that you want the job to run at 1 a.m. on
the first Saturday of each month. You put in a cron job to run at
12:30 a.m. on the 1st DAY of each month, and have that cron job
launch an "at" job to run at 1 a.m. on the next Saturday, which could
be as soon as 30 minutes later. Tweak the names and numbers to your
heart's delight, but the concept remains.
The cron line (SunOS 4.x):
30 0 1 * * /home/myacct/bin/next.Saturday
The next.Saturday script (mode 755):
at -c 0100 Sat first.Saturday.of.month
File "first.Saturday.of.month" contains... oh, you can figure it out.
--
Steve Alter <alter@ttidca.tti.com>
{csun,philabs,psivax,pyramid,quad1,rdlvax,retix}!ttidca!alter
Citicorp/TTI, Santa Monica CA (213) 450-9111 x2541
-----------------------------
From: Dave Corcoran <dave@aspect.uucp>
Subject: Re: Cron - First Saturday of the month
Date: 15 Aug 90 13:38:07 GMT
To: unix-wizards@sem.brl.mil
In article <1990Aug11.030818.28876@watserv1.waterloo.edu>, dmcanzi@watserv1.waterloo.edu (David Canzi) writes:
> This is better done using awk:
>
> if [ `date | awk '{print $3}'` -le 7 ]; then
or:
if [ `date +%d` -le 7 ]
--
David Corcoran -@@
uunet!aspect!dave ~
Good, fast, cheap; pick any two.
-----------------------------
From: B|rje Josefsson <bj@dc.luth.se>
Subject: Re: Cron - First Saturday of the month
Date: 15 Aug 90 17:26:59 GMT
To: unix-wizards@sem.brl.mil
Slightly a side question according to the Subject:, but how to setup a
command for execution on the LAST day of the month ONLY?
I could use:
0 0 31 1 * command
0 0 28 2 * command
0 0 31 3 * command
and so on
but that will not work on leap years...
--Borje
-----------------------------------------------------------------------------
Borje Josefsson, Computer centre, University of Lulea, S-951 87 Lulea, Sweden
Tel: +46 920 91 262 (direct), +46 920 91 000 (operator). Fax: +46 920 972 88
Domain: bj@dc.luth.se Path: {uunet,mcsun,sunic}!dc.luth.se!bj
-----------------------------
From: Christopher R Volpe <volpe@underdog.crd.ge.com>
Subject: Re: Cron - First Saturday of the month
Date: 15 Aug 90 20:57:54 GMT
Sender: news@crdgw1.crd.ge.com
To: unix-wizards@sem.brl.mil
In article <1489@hagbard.dc.luth.se>, bj@dc.luth.se (B|rje Josefsson) writes:
|>Slightly a side question according to the Subject:, but how to setup a
|>command for execution on the LAST day of the month ONLY?
|>
|>I could use:
|> 0 0 31 1 * command
|> 0 0 28 2 * command
|> 0 0 31 3 * command
|> and so on
|>but that will not work on leap years...
|>
|>--Borje
Set the date on your machine to one day ahead of the real date, and tell
cron to run your application on the first of each month. ( 1/2 :-) )
==================
Chris Volpe
G.E. Corporate R&D
volpecr@crd.ge.com
-----------------------------
From: Larry Wall <lwall@jpl-devvax.jpl.nasa.gov>
Subject: Re: Cron - First Saturday of the month
Date: 15 Aug 90 23:14:42 GMT
To: unix-wizards@sem.brl.mil
In article <1489@hagbard.dc.luth.se> bj@dc.luth.se (B|rje Josefsson) writes:
: Slightly a side question according to the Subject:, but how to setup a
: command for execution on the LAST day of the month ONLY?
:
: I could use:
: 0 0 31 1 * command
: 0 0 28 2 * command
: 0 0 31 3 * command
: and so on
: but that will not work on leap years...
I'd suggest (surprise, surprise)
0 0 * * * perl -e '(localtime(time + 24*60*60))[3] == 1 && exec "command"'
or, more concisely
0 0 * * * perl -e 'exit+(localtime time+86400)[3]-1' && command
Larry Wall
lwall@jpl-devvax.jpl.nasa.gov
-----------------------------
From: David Canzi <dmcanzi@watserv1.waterloo.edu>
Subject: Re: Cron - First Saturday of the month
Date: 16 Aug 90 00:22:29 GMT
To: unix-wizards@sem.brl.mil
In article <3706@aspect.UUCP> dave@aspect.UUCP (Dave Corcoran) writes:
>In article <1990Aug11.030818.28876@watserv1.waterloo.edu>, dmcanzi@watserv1.waterloo.edu (David Canzi) writes:
>> if [ `date | awk '{print $3}'` -le 7 ]; then
>
>or:
>if [ `date +%d` -le 7 ]
This doesn't work on all the machines I have access to, so I prefer
the solution using awk.
--
David Canzi
-----------------------------
From: "LCDR Michael E. Dobson" <rdc30med@nmrdc1.nmrdc.nnmc.navy.mil>
Subject: Re: Please add me to User list
Date: 15 Aug 90 13:02:42 GMT
To: unix-wizards@sem.brl.mil
Periodicly we see these types of messages appearing in the various news groups
that also include gatewayed mailing lists. This is generaly caused by two
mechanisms. The first is posting the request to the gatewayed mailing list,
ie info-unix@sem.brl.mil or unix-wizards@sem.brl.mil, instead of the
administrative list, ie info-unix-request@sem.brl.mil. This is due to ignorance
on the part of the person trying to get on the list (they may not have news
on their system). The second and more serious reason is the request mail
address being incorrectly gatewayed into the newsgroup. If this is happening,
flames should be directed to the list maintainer, not the poor user who has no
control over how his message is treated once it reaches the mail gateway system.
--
Mike Dobson, Sys Admin for | Internet: rdc30med@nmrdc1.nmrdc.nnmc.navy.mil
nmrdc1.nmrdc.nnmc.navy.mil | UUCP: ...uunet!mimsy!nmrdc1!rdc30med
AT&T 3B2/600G Sys V R 3.2.2 | BITNET: dobson@usuhsb.bitnet
WIN/TCP for 3B2 | MCI-Mail: 377-2719 or 0003772719@mcimail.com
-----------------------------
From: Grant Grundler <grant@pescara.orc.olivetti.com>
Subject: Re: Please add me to User list
Date: 15 Aug 90 17:17:16 GMT
Control: cancel <49280@ricerca.UUCP>
Sender: news@orc.olivetti.com
To: unix-wizards@sem.brl.mil
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: Please add me to User list
Date: 15 Aug 90 17:35:13 GMT
To: unix-wizards@sem.brl.mil
>Looks like the somebody needs to learn how to use "rn"!
No, somebody just needs to have the protocol for joining/leaving mailing
lists explained to them before being told about those mailing lists.
There's no guarantee that his machine necessarily *gets* netnews; if it
doesn't, "rn" (or any other newsreader) won't do him a lot of good....
-----------------------------
From: dxg@cai.com
Subject: AT&T 3B2, PC-NFS, Curses - reverse video with werase()
Keywords: ATT 3B2, PC-NFS, CURSES
Date: 15 Aug 90 14:12:17 GMT
To: unix-wizards@sem.brl.mil
/**********************************************************************
*
* I am using PC-NFS Version 3.0 to connect to an AT&T 3B2 running UNIX
* System V Release 3.2.1. My environment variable TERM is 'vt100'.
*
* I am developing a large application using Curses and have run into
* a problem. I have to output a string to a window, in reverse video
* and then clear this window. But for some reason when the window
* is cleared the row that contains the reverse video character(s)
* and all the rows that follow are cleared (output) in reverse video.
*
* This problem occurs when the last character output is in reverse video.
*
* The problem does not occur, if the last non-blank character output is
* not in reverse video.
*
* The following source file is a small scale version of the problem.
*
* The compile command that I am using is:
* cc $*.c -o $* -lm -lcurses
*
* Please let me know how I can work around this problem, or what I
* am doing wrong.
*
* Thanks,
* Constantine "Dean" Grammas
* Computer Associates International
* 201 University Avenue
* Westwood MA, 02090
* (617) 329-7700 x3314
*
*/
/*********************
**** TEST ROUTINE ****
**********************/
#include <curses.h>
/*
* Repaint the the specified window
*/
rep_win( wid )
WINDOW *wid;
{
/* just for arguments sake, turn off the reverse video attribute
*/
wattroff( wid, A_REVERSE );
wnoutrefresh( wid );
touchwin( wid );
doupdate();
} /* END rep_win */
/*
* Repaint the specified window and wait for a key stroke
*/
get_key( wid )
WINDOW *wid;
{
/* just for arguments sake, turn off the reverse video attribute
*/
wattroff( wid, A_REVERSE );
rep_win( wid );
beep();
wgetch( wid );
} /* END get_key */
/*
* Clear the specified window and then repaint it
*/
clr_win( wid )
WINDOW *wid;
{
/* just for arguments sake, turn off the reverse video attribute
*/
wattroff( wid, A_REVERSE );
werase( wid );
rep_win( wid );
} /* END clr_win */
main()
{
WINDOW *wid;
stdscr = initscr();
/* output a line of text in reverse video, and wait for a key stroke
*/
wattrset( stdscr, A_REVERSE );
mvwaddstr( stdscr, 10,10, "Press any key." );
wattroff( stdscr, A_REVERSE );
wattrset( stdscr, A_NORMAL );
get_key( stdscr );
/* clear the window, and wait for a keystroke
*
* NOTE: this is where the problem occurs.
*/
wattrset( stdscr, A_NORMAL );
clr_win( stdscr );
get_key( stdscr );
endwin();
} /* END main */
-----------------------------
From: MSHAW@wl9.prime.com
Subject: Re: sendmail config file question
Date: 15 Aug 90 14:49:00 GMT
Nf-ID: #R:sparkyfs.istc.sri.com:-3255900:WL9:16300003:000:2301
Nf-From: WL9.Prime.COM!MSHAW Aug 15 14:49:00 1990
To: unix-wizards@sem.brl.mil
I'm not a sendmail guru yet but here's my help anyway.
To recap you put.....
| We're getting ready to change our domain name, and I want to make sendmail
| clever enough to handle mapping the old domain to the new one. Problem is,
| we're already doing that from the domain name of about a year ago.
|
| Basically, right now I have:
|
| DDitstd.sri.com current domain name
| DEistc.sri.com old domain name
|
| S1
| R$*<@$-.$E>$* $1<@$2.$D>$3 change domain name
| R$*<@$E>$* $1<@$D>$2 change domain name
|
| and likewise for S2. Now, to handle both old domain names, I figured I
| could use a class:
|
| DDerg.sri.com new domain name
| CDistc.sri.com itstd.sri.com old domain names
|
| S1
| R$*<@$-.$=D>$* $1<@$2.$D>$3 change domain name
| R$*<@$=D>$* $1<@$D>$2 change domain name
|
| and likewise for S2.
|
| But this doesn't work; the matches against the class fail. Reading the
| sendmail manual, it mentions something about "token" being the unit of
| a class. I'm assuming the match is failing because "istc.sri.com" and
| "itstd.sri.com" are three tokens each rather than one.
|
| Is this right? If so, is there a way to do what I want with classes?
|
Unless you've done a typo' then you've defined a macro (with the D) and a
class (with the C) both the macro and the class have the same name (D). I'd
write something like the below instead.
#
# Define Macro N (New-domain-name)
# and Class O (Old-domain-names)
#
DNerg.sri.com new domain name
COistc.sri.com itstd.sri.com old domain names
S1
R$*<@$-.$=O>$* $1<@$2.$O>$3 change domain name
R$*<@$=O>$* $1<@$O>$2 change domain name
Of course I'd also have the old domains defined in a file and then use the
F command instead of C thus:
FO/usr/lib/domains.old old domain names
domains.old would contain..
istc.sri.com
itstd.sri.com
Then I'd be able to update the list of old domains without having to restart
and reconfigure sendmail (just in case I moved yet again).
Mike Shaw.
/* The opinions expressed in this notice are my own and not those of Prime
Computer Inc. */
-----------------------------
From: Neil Rickert <rickert@mp.cs.niu.edu>
Subject: Re: sendmail config file question
Date: 15 Aug 90 22:41:30 GMT
To: unix-wizards@sem.brl.mil
In article <16300003@WL9.Prime.COM> MSHAW@WL9.Prime.COM writes:
>
>I'm not a sendmail guru yet but here's my help anyway.
>
>Unless you've done a typo' then you've defined a macro (with the D) and a
>class (with the C) both the macro and the class have the same name (D). I'd
>write something like the below instead.
There is nothing wrong with a macro and a class having the same name. If
they are related it may even be a good idea.
>
>Of course I'd also have the old domains defined in a file and then use the
>F command instead of C thus:
>
>FO/usr/lib/domains.old old domain names
>
>domains.old would contain..
>
>istc.sri.com
>itstd.sri.com
>
>Then I'd be able to update the list of old domains without having to restart
>and reconfigure sendmail (just in case I moved yet again).
>
Wrong! You wouldn't have to change sendmail.cf. But you would still need
to rebuild the freeze file (if used) with sendmail -bz, and you would still
need to kill and restart the daemon.
--
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
Neil W. Rickert, Computer Sci Dept, Northern Illinois U., DeKalb IL 60115
rickert@cs.niu.edu +1-815-753-6940
=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=
-----------------------------
From: Thomas Truscott <trt@rti.rti.org>
Subject: Re: Is HDB locking safe?
Date: 15 Aug 90 19:46:12 GMT
To: unix-wizards@sem.brl.mil
> ... HDB assumes that if the pid recorded
> in the lock file no longer corresponds to an active process, the lock file is
> defunct and can safely be removed. I can't for the life of me figure out a
> safe way of doing this.
A crucial detail in recovering from a breakdown in the lock protocol
is avoiding a race between two or more processes that are simultaneously
attempting recovery. Usually a strategic pause is all that is needed,
and as you can see in the HDB code below there is just such a pause.
> static int
> checklock(lockfile)
> char *lockfile;
> {
> ...
> if ((lfd = open(lockfile, 0)) < 0)
> return(0);
> ...
> if ((kill(lckpid, 0) == -1) && (errno == ESRCH)) {
> /*
> * If the kill was unsuccessful due to an ESRCH error,
> * that means the process is no longer active and the
> * lock file can be safely removed.
> */
> unlink(lockfile);
> sleep(5); /* avoid a possible race */
> return(1);
> }
>
> In this code there is no guarantee that lfd and lockfile correspond to the
> same file at the time of the unlink.
But there *is* a guarantee -- the "sleep(5);"!!
[I changed the sleep() line to match the one in 4.3 BSD uucp "ulockf.c"]
Consider a process "X" that discovers that the locking
process has terminated. X unlinks the lockfile,
but then it *pauses* before it attempts to grab the lock for itself
(done by code not shown above).
Now consider scenario #1 for another process "Y":
At nearly the same instant Y discovers
the dead lock, so it also unlinks the lockfile
(of course only one unlink can succeed) and it *also pauses*.
Whenever X and/or Y resume there is no lock present,
so attempts to grab it proceed in the usual way (code not shown above).
Now consider scenario #2 for Y:
Just after X has unlinked the lockfile, Y calls checklock()
and discovers no lock is present. No problem, it just
attempts to grab the lock in the usual way (code not shown above).
When X awakes from its slumber it will discover that Y has
already grabbed the lock, so X will just have to wait.
The HDB code is nice, but does have flaws:
(a) A "sleep(1);" is not enough to avoid a race on a very busy system.
(b) Lock recovery is obscure, so the sleep() call should be commented.
(c) Protocol breakdown is a bad thing, and should be reported:
logent(lockfile, "DEAD LOCK");
The 4.3 BSD ulockf.c routine has all of these nice features.
Tom Truscott
-----------------------------
From: Claude Goutier <goutier@iro.umontreal.ca>
Subject: Re: Is HDB locking safe?
Date: 16 Aug 90 09:17:30 GMT
Sender: news@iro.umontreal.ca
To: unix-wizards@sem.brl.mil
In article <4024@rtifs1.UUCP> trt@rti.rti.org (Thomas Truscott) writes:
>
>A crucial detail in recovering from a breakdown in the lock protocol
>is avoiding a race between two or more processes that are simultaneously
>attempting recovery. Usually a strategic pause is all that is needed,
>and as you can see in the HDB code below there is just such a pause.
>
> ...
>
>The HDB code is nice, but does have flaws:
>(a) A "sleep(1);" is not enough to avoid a race on a very busy system.
>(b) Lock recovery is obscure, so the sleep() call should be commented.
>(c) Protocol breakdown is a bad thing, and should be reported:
> logent(lockfile, "DEAD LOCK");
>The 4.3 BSD ulockf.c routine has all of these nice features.
>
> Tom Truscott
If a sleep(1) is not long enough, why does a sleep(5) is?
If something is not prohibited to happen by construction (read solid
and serious interlock), whatever small the probability of it to happen,
it WILL happen!
One should never try to be smarter than a race condition. The only way
is to use true and solid interlocks (which should be provided in the
kernel and with the cooperation of the hardware). Have you ever programmed
on a machine with a fast CPU and ten peripheral processors all accessing
the same memory at the same time ?
--
Claude Goutier Services informatiques, Universite de Montreal
C.P. 6128, Succ "A", Montreal (Quebec)
goutier@jsp.umontreal.ca Canada H3C 3J7
-----------------------------
From: Roar Steen <roar@hpserv1.uit.no>
Subject: Broadcast UDP packets
Date: 15 Aug 90 19:56:59 GMT
Sender: USENET News System <news@hod.uit.no>
To: unix-wizards@sem.brl.mil
Is there anybody out there who has some piece of code that
demonstrates broadcast of UDP-packets. My system is a HP9000/375
workstation running HP-UX 7.0.
--
//// Roar Steen // N-9001 TROMSOE, NORWAY /
/// Computer Science Department // Phone : + 47 83 44051 //
// University of Tromsoe // Telefax: + 47 83 44580 ///
/ NORWAY // Email: roar@sfd.uit.no ////
-----------------------------
From: 8592x2 <jeff@astph.uucp>
Subject: shmat() system call?
Keywords: shmat() systemV
Date: 15 Aug 90 20:11:02 GMT
To: unix-wizards@sem.brl.mil
Question concerning the shared memory attach call:
I am writing a shared memory allocation manager for a multi-user
database. This manager will allow several processes to be attached
to the same memory segment at the same time. The first process to
attach to the shared memory segment will be returned a memory address
that points to the shared memory block.
I need to know if additional attaches by other processes will be
guaranteed to return the same address as that the first process
was returned. I am aware that you can request a particular address,
but why bother communicating that information between the processes
if the same address is returned anyway? I would appreciate any
answers or direction to documentation.
Thanks jeff martin
astph!jeff@psuvax1
philadelphia phillies
-----------------------------
From: Warren Tucker <wht@n4hgf.mt-park.ga.us>
Subject: Re: shmat() system call?
Keywords: shmat() systemV
Date: 16 Aug 90 02:37:45 GMT
To: unix-wizards@sem.brl.mil
In article <27@astph.UUCP> jeff@astph.UUCP (8592x2) writes:
>
>Question concerning the shared memory attach call:
>
>I am writing a shared memory allocation manager for a multi-user
>database.
>I need to know if additional attaches by other processes will be
>guaranteed to return the same address as that the first process
>was returned.
To be sure, specify the attach address, regardless of what the FM says.
Make a small program that passes 0 for the address and see what it
returns. Then, use that value hardcoded, possibly #defined for each
arcitecture you plan to run the program on.
I.E.,
/*---------------------- header file --------------------*/
#if defined(M_I286)
#define SHMPTR char far *
#define SYSPTR struct system_control *
#else
#define SHMPTR char *
#define SYSPTR struct system_control *
#endif
#if defined(M_SYS5)
#if defined(M_I386)
#define SHM_ATTACH_ADDR ((SHMPTR)0x67000000L) /* 386 */
#else
#define SHM_ATTACH_ADDR ((SHMPTR)0x00670000L) /* 286 */
#endif
#else /* not xenix */
#ifdef (pyr)
#define SHM_ATTACH_ADDR ((SHMPTR)0xC0000000L) /* PYRAMID */
#else
#define SHM_ATTACH_ADDR ErrorInHeaderFile
#endif
#endif
/*---------------------- code file --------------------*/
if((sys = shmat(*pshmid,SHM_ATTACH_ADDR,0)) !=
(SHMPTR)SHM_ATTACH_ADDR)
{
/* attach error: either returned (SHMPTR)-1 or wrong address */
}
-----------------------------------------------------------------------
Warren Tucker, TuckerWare gatech!n4hgf!wht or wht@n4hgf.Mt-Park.GA.US
"Tell the moon; don't tell the March Hare: He is here. Do look around."
-----------------------------
From: "BURNS,JIM" <gt0178a@prism.gatech.edu>
Subject: Re: shmat() system call?
Date: 16 Aug 90 05:41:44 GMT
To: unix-wizards@sem.brl.mil
in article <27@astph.UUCP>, jeff@astph.UUCP (8592x2) says:
>
>
> Question concerning the shared memory attach call:
>
> I am writing a shared memory allocation manager for a multi-user
> database. This manager will allow several processes to be attached
> to the same memory segment at the same time. The first process to
> attach to the shared memory segment will be returned a memory address
> that points to the shared memory block.
>
> I need to know if additional attaches by other processes will be
> guaranteed to return the same address as that the first process
> was returned. I am aware that you can request a particular address,
> but why bother communicating that information between the processes
> if the same address is returned anyway? I would appreciate any
> answers or direction to documentation.
I don't see why not. The shmget(2) routine specifies the memory block
size. All the shmat(2) routine does is return a pointer to the beginning
of that block (by default). The same block is returned to different
processes if they use the same shmid returned by shmget(2). Adapted from
the HP 9000/800 HP-UX Real Time Programmers Manual:
On shmget(2):
"If your communication application consists of related processes, you
should call shmget(2) with the key parameter set to IPC_PRIVATE in the
following way:
myshmid = shmget (IPC_PRIVATE, 4096, 0600);
"This call to shmget(2) returns a unique shared memory identifier (shmid),
which is saved in the variable myshmid, for the newly created shared
memory segment. The size of the segment is 4096 bytes and its access
permissions are read and write permission for the owner. This call to
shmget(2) should appear in your program sometime before the fork()
statement so that the child processes in your communication application
will inherit myshmid.
"If your communication application consists of unrelated processes, you
should call shmget(2) with the key parameter set to the return value of
the ftok() subroutine [or just use an ascii representation of a 4
character string that you know will be unique. - JB ] [...] As an example,
all unrelated processes in a communication application can call shmget(2)
in the following [altered - JB ] way:"
myshmid = shmget (0x50485331, 4096, IPC_CREAT|600);
to use a key of "PHS1".
On shmat(2):
"Once a process has a valid shmid, it usually wants to attach, perhaps to
lock, to read and/or to write to, and then to detach the shared memory
segment. [...]
"A process must invoke the shmat() system call to attach a shared memory
segment to the data space of the process. The man page for shmop(2) lists
three parameters for shmat(): shmid, shmaddr, and shmflg.
"The first parameter, shmid, must be a valid shared memory identifier as
explained in the previous section.
"The second parameter, shmaddr, is the attach address of the shmid
parameter. Parameter shmaddr should be 0 in almost all cases. Only at
certain times and only in certain implementations of HP-UX can shmaddr be
other than 0. If a previous shmat() has not been called on the shmid; that
is, if the shared memory segment has not already been attached, then the
only correct value for shmaddr is 0. If, however, some process has already
called shmat() on the specified shmid, then the shmaddr can be 0 or some
other implementation - dependent value. [...] [As it turns out, non-zero
parameters aren't supported at all on the model 800 architechture - only
the 300. -JB ]
"The third parameter of shmat(), shmflg, is used only to further restrict
the owner's access permissions to the shared memory segment. [...]"
Hope this answers your question.
--
BURNS,JIM
Georgia Institute of Technology, Box 30178, Atlanta Georgia, 30332
uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!gt0178a
Internet: gt0178a@prism.gatech.edu
-----------------------------
From: "BURNS,JIM" <gt0178a@prism.gatech.edu>
Subject: Re: shmat() system call?
Date: 16 Aug 90 06:32:18 GMT
To: unix-wizards@sem.brl.mil
in article <187@n4hgf.Mt-Park.GA.US>, wht@n4hgf.Mt-Park.GA.US (Warren Tucker) says:
< In article <27@astph.UUCP> jeff@astph.UUCP (8592x2) writes:
< To be sure, specify the attach address, regardless of what the FM says.
< Make a small program that passes 0 for the address and see what it
< returns. Then, use that value hardcoded, possibly #defined for each
< arcitecture you plan to run the program on.
What if yours is not the only application creating and deleting shared
memory segments? Are you saying you always get the same address?
~
~
~
~
~
~
~
~
~
"/usr/tmp/vn002876" 13 lines, 646 characters
still want to post it ? n
not posted
:more (34%):
--
BURNS,JIM
Georgia Institute of Technology, Box 30178, Atlanta Georgia, 30332
uucp: ...!{decvax,hplabs,ncar,purdue,rutgers}!gatech!prism!gt0178a
Internet: gt0178a@prism.gatech.edu
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: Curses question
Keywords: key interpretation problems
Date: 15 Aug 90 20:33:18 GMT
To: unix-wizards@sem.brl.mil
>(editor's note: This may be a duplicate transmision. Sorry if you got it
>twice)
I only saw it once, but I did see the matching posting in
"comp.sys.sun"....
>The first one involves interpretation of input keys. How can one tell the
>difference between the forward and backward tabs?? When I run my test
>program, I get 0x09 for both.
As noted, the problem here is that in a "shelltool" window, there *is*
no difference. What's more, different terminals may transmit different
things for the "backward tab", assuming they even have one; the BSD
"curses" doesn't have any way of recognizing the particular terminal's
notion of a "backward tab" sequence and translating it into some common
code for "backward tab". The S5 "curses" might be able to do that.
>In addition, the code I'm getting in my test program for a return is
>different that the code which is returned in the real program (0x0a vs.
>0x0d) and yes, these two programs are being run on the same system.
But probably *not* with the same modes. 0x0a is NL, and 0x0d is CR.
The RETURN key on most terminals - including the "terminal" emulated by
a "shelltool" - sends CR; however, in some modes the UNIX tty driver
turns CR into NL. Check out such "curses" functions as "nl()" and
"nonl()", which affect whether this mapping is in effect....
-----------------------------
From: William Kucharski <kucharsk@number6.solbourne.com>
Subject: Re: Another "why won't this work" program
Date: 16 Aug 90 00:26:38 GMT
Sender: news@solbourne.com
To: unix-wizards@sem.brl.mil
In article <24183@adm.BRL.MIL> BKEHOE@widener writes:
>/*
> * This is being run on a Sun SS1 under 4.0.3.
> * Theoretically, according to the Design & Implementation of 4.3BSD Unix,
> * this should print out the ascii version of each process's current
> * directory...instead, it chokes on u->u_cwd->cw_dir, which is in the
> * u struct in sys/user.h .. any help, suggestions, etc would be greatly
> * appreciated.
>
> */
>
>/*
> * cc -o cwd cwd.c -lkvm
> */
>
>#include <stdio.h>
>#include <kvm.h>
>#include <fcntl.h>
>#include <ctype.h>
>#include <pwd.h>
>#include <sys/param.h>
>#include <sys/time.h>
>#include <sys/proc.h>
>#include <sys/user.h>
...
> (void) printf("Name\t\tDir\n");
> kvm_setproc (kd);
> while ((proc = kvm_nextproc (kd)))
> if (proc->p_stat != SZOMB && proc->p_uid) {
> if (!(user = kvm_getu(kd, proc)))
> continue;
> (void) printf("%s\n", (getpwuid(proc->p_uid))->pw_name);
>/* Curtains & Slow Music */
> (void) printf("%s\n", user->u_cwd->cw_dir);
>/* It dies, but the user structure's fine (printing user->u_comm works); I
> stepped thru it with gdb & discovered that the pointer user->u_cwd is off in
> never-never-land; is it a valid entry in
>the user structure? */
> }
>}
That's because the user->u_cwd pointer is really a pointer into the kernel's
memory space, rather than user memory space. You need to do something like
the following to read the contents of the kernel memory in question into user
space:
...
char dir[MAXPATHLEN];
char rootdir[MAXPATHLEN];
struct ucwd cwd;
if (kvm_read(kd, (unsigned long)userp->u_cwd, (char *)&cwd,
sizeof(struct ucwd)) == sizeof(struct ucwd)) {
if ((kvm_read(kd, (unsigned long)cwd.cw_dir, dir, MAXPATHLEN)
== MAXPATHLEN) && (kvm_read(kd, (unsigned long)cwd.cw_root, rootdir,
MAXPATHLEN) == MAXPATHLEN)) {
if ((*rootdir) || (*dir))
printf("cwd: %s%s\n", rootdir, dir);
else
printf("cwd: /\n");
}
}
...
--
===============================================================================
| Internet: kucharsk@Solbourne.COM | William Kucharski |
| uucp: ...!{boulder,sun,uunet}!stan!kucharsk | Solbourne Computer, Inc. |
=== The sentiments expressed above are MY opinions, NOT those of Solbourne. ===
-----------------------------
From: "jeffrey.n.jones" <jeffj@cbnewsm.att.com>
Subject: How to restrict commands in rsh?
Date: 15 Aug 90 21:37:00 GMT
To: unix-wizards@sem.brl.mil
A co-worker and I were trying to figure out how to restrict the commands
a user can use in rsh. In the manual there is a mention of a directory
where you can put the commands that you want to restrict called
/usr/rbin
How do you do this? Do you put all of the commands in a single file? What
do you call this file? Thanks ahead of time for any help!
Jeff Jones
--
Jeff Jones | Prediction is very difficult, especially
UUCP uunet!seeker!jeffj | about the future.
Infolinc BBS 415-778-5929 | Niels Bohr
-----------------------------
From: Bertrand Meyer <bertrand@eiffel.uucp>
Subject: Vi fails on a Sun-4
Keywords: Illegal instruction
Date: 15 Aug 90 22:09:47 GMT
To: unix-wizards@sem.brl.mil
Has anyone run into the following problem, which
is becoming an increasing nuisance for me?
Vi (on a Sun-4, running SunOS 4.0) fails
according to totally unpredictable patterns.
For example (vg is an alias that uses vi):
> [Rome] bm 592 - vg instruction
> Illegal instruction (core dumped)
> [Rome] bm 593 - vi Grammar/instruction
> Illegal instruction (core dumped)
> [Rome] bm 594 - vi Grammar/instruction
> Illegal instruction (core dumped)
> [Rome] bm 595 - cd Grammar
> [Rome] bm 596 - vi instruction
> Illegal instruction (core dumped)
I have experienced similar problems for a long
time, but it used to be only when calling vi with
several file arguments (I have many scripts which do
this, based on grep searching). Now, as the above shows,
it's occurring even with just one file!
Another example occurred as I was trying to send mail
(describing the problem!) and the ~v command of mail
failed with ``Fatal error in "usr/ucb/vi"''.
The problem does not occur identically in different
windows. Usually command windows fail less often than
shell windows. Yesterday, I experienced a situation
with two windows, where vi would work in window A
(a command window) except if the number of file arguments
was equal to 2, and would work in window B (a shell
window) for 1 or 2 arguments, but apparently for no
other number of arguments!
I would be grateful if anyone has any suggestion about
what is going on (other than ``switch to Emacs'').
A text editor seems a pretty basic tool to me, and
after all these years one might hope that vi would
work. I don't suspect Bill Joy reads this, however.
I would appreciate mail replies to bertrand@eiffel.com.
If I receive anything of general interest I will post a
summary.
Thanks in advance.
-- Bertrand Meyer
Interactive Software Engineering, Santa Barbara, CA.
bertrand@eiffel.com
-----------------------------
From: Mike McNally <m5@lynx.uucp>
Subject: Directory compression
Keywords: 4.3BSD
Date: 15 Aug 90 23:03:16 GMT
To: unix-wizards@sem.brl.mil
Does 4.3BSD (or anything else) dynamically compress directories when
entries are removed? If so, how does the system deal with
consistency? Like if I'm reading while something else is unlinking and
the directory is being compressed, how does the world go on living?
--
Mike McNally Lynx Real-Time Systems
uucp: {voder,daver}!lynx!m5 phone: 408 370 2233
Where equal mind and contest equal, go.
-----------------------------
End of UNIX-WIZARDS Digest
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----Reason for mail failure follows----
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----Transcript of message follows----
Date: 17 Aug 90 05:23:00 MDT
From: unix-wizards@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#119
To: "math!ckaul" <math!ckaul@cs.sandia.gov>
Return-Path: <incoming-unix-wizards-request@sandia.gov>
Received: from SEM.BRL.MIL by sandia.gov with SMTP ;
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Date: Fri, 17 Aug 90 05:45:03 EST
From: The Moderator (Mike Muuss) <Unix-Wizards-Request@BRL.MIL>
To: UNIX-WIZARDS@BRL.MIL
Reply-To: UNIX-WIZARDS@BRL.MIL
Subject: UNIX-WIZARDS Digest V10#119
Message-ID: <9008170545.aa01271@SEM.BRL.MIL>
UNIX-WIZARDS Digest Fri, 17 Aug 1990 V10#119
Today's Topics:
"to big" error on PDP-11/73
Re: sed bug?
Re: csh weirdness (HELP!)
Re: shmat() system call?
UNIX System Administration/Programming Positions Available
Re: Vi fails on a Sun-4
Re: Checkpoint/Restart (was "no subject - file transmission")
Re: Another "why won't this work" program
Re: Is HDB locking safe?
Problems with DIGIBOARD PC/4
-----------------------------------------------------------------
From: "Jay A. Snyder" <jay@gdx.uucp>
Subject: "to big" error on PDP-11/73
Date: 15 Aug 90 21:28:40 GMT
To: unix-wizards@sem.brl.mil
I compiled C-Kermit ver. 4E on a Tektronix model 8061 (DEC LSI 11/73).
The OS is called TNIX (tek's version of V7).
When I tried to run the executable, it said:
kermit: to big
The machine has 512K of RAM and 4700 blocks of swap. The executable is
only 114K. The largest executables I could find on the machine where
less than 64K. Is there a limit to the executable size on 11/73's?
I'm also trying to get Micro-Emacs to compile, and I get
"too many defines"
error from the c-compiler. Any one have any ideas there?
Thanks,
J
...uunet!wa3wbu!gdx!jay
--
==============================================================================
Jay A. Snyder "Let Me Up! I've had enough"
wa3wbu!gdx!jay@uunet.uu.net
uunet!wa3wbu!gdx!jay
-----------------------------
From: "John F. Haugh II" <jfh@rpp386.cactus.org>
Subject: Re: sed bug?
Date: 16 Aug 90 04:40:16 GMT
X-Clever-Slogan: Recycle or Die.
To: unix-wizards@sem.brl.mil
In article <24172@adm.BRL.MIL> stanonik@nprdc.navy.mil (Ron Stanonik) writes:
>We've run into what appears to be a sed bug in sunos4.X (sun3 snd sun4)
>and in sysVr3 (on a 3b2). Here's a little sed program to demonstrate it
>
>1 s/.*/&/p
>d
>
>I'd expect this to print only the first line, and indeed that's what happens
>in 4.3bsd (on a vax 780). In sunos4.X and sysVr3, however, nothing is printed.
By all accounts it is fixed in BSD 4.3 and broken in every other version of
SED I've had my hands on.
The way the bug was reported for AIX 3.1 was
% sed -e 's/abc/ABC/p' -e d << EOF
abc
abc123
EOF
and the output should have been
ABC
ABC123
but instead, nothing at all was printed.
>Bug?
Yes. Bug.
--
John F. Haugh II UUCP: ...!cs.utexas.edu!rpp386!jfh
Ma Bell: (512) 832-8832 Domain: jfh@rpp386.cactus.org
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: sed bug?
Date: 16 Aug 90 19:41:54 GMT
To: unix-wizards@sem.brl.mil
>Bug?
Or misfeature, although some scripts in S5 (among others, "lint", I
think) depend on that behavior. As I remember, the behavior exhibited
by S5 was also exhibited in UNIX/32V (or, at least, the part of the code
that differs was basically the same as in S5), while in V7 it worked the
BSD way.
I think the 32V code was older (yes, 32V was allegedly a V7 port to the
VAX, but they may have started with something older than V7), so it
*seems* the change from the 32V/S5 behavior to the V7/BSD behavior might
have been intended as a bug fix or improvement. I think the S5 "lint"s
dependency on the 32V/S5 behavior can be fixed; I think there are cases
where dependency on the V7/BSD behavior cannot.
POSIX 1003.2 may specify that this has to be done the V7/BSD way.
-----------------------------
From: Rob McMahon <cudcv@warwick.ac.uk>
Subject: Re: csh weirdness (HELP!)
Date: 16 Aug 90 09:04:17 GMT
Sender: Network news <news@warwick.ac.uk>
To: unix-wizards@sem.brl.mil
In article <8000007@hpopd.HP.COM> bd@hpopd.HP.COM (Bob Desinger) writes:
>> to kill every instance of a.out I get
>> `ps | grep a.out | awk '{printf("%d ",$1);}'`: Ambiguous.
>
>Can you work around this by changing the awk program to generate the
>kill commands, then piping the awk output to the shell? ...
The best workaround is just to use
\kill `ps | grep a.out | awk '{printf("%d ",$1);}'`
to avoid using the shell builtin.
Rob
--
UUCP: ...!mcsun!ukc!warwick!cudcv PHONE: +44 203 523037
JANET: cudcv@uk.ac.warwick INET: cudcv@warwick.ac.uk
Rob McMahon, Computing Services, Warwick University, Coventry CV4 7AL, England
-----------------------------
From: Thomas Tornblom <thomas@uplog.se>
Subject: Re: shmat() system call?
Date: 16 Aug 90 10:32:52 GMT
Sender: Thomas Tornblom <thomas@uplog.se>
To: unix-wizards@sem.brl.mil
In article <187@n4hgf.Mt-Park.GA.US> wht@n4hgf.Mt-Park.GA.US (Warren Tucker) writes:
In article <27@astph.UUCP> jeff@astph.UUCP (8592x2) writes:
>
>Question concerning the shared memory attach call:
>
>I am writing a shared memory allocation manager for a multi-user
>database.
>I need to know if additional attaches by other processes will be
>guaranteed to return the same address as that the first process
>was returned.
To be sure, specify the attach address, regardless of what the FM says.
Make a small program that passes 0 for the address and see what it
returns. Then, use that value hardcoded, possibly #defined for each
arcitecture you plan to run the program on.
[example deleted]
This is not guaranteed to work. Typically the kernel allocates the addresses
depending of the memory layout of the running process.
Our sysV.2 68k kernel uses the current end of bss rounded up with some
constant as the lowest base for shm. It also checks that the segment doesn't
overlap into the stack or other shared memory segments.
If you must have the same addresses between the processes (which is nice for
pointers and stuff) I'd pick some high constant address, say 0x[48c]0000000
or so that isn't likely to map onto anything on the architectures you're using.
Thomas
--
Real life: Thomas Tornblom Email: thomas@uplog.se
Snail mail: TeleLOGIC Uppsala AB Phone: +46 18 189406
Box 1218 Fax: +46 18 132039
S - 751 42 Uppsala, Sweden
-----------------------------
From: Christopher R Volpe <volpe@underdog.crd.ge.com>
Subject: Re: shmat() system call?
Date: 16 Aug 90 17:47:23 GMT
Sender: news@crdgw1.crd.ge.com
To: unix-wizards@sem.brl.mil
In article <THOMAS.90Aug16123252@uplog.uplog.se>, thomas@uplog.se
(Thomas Tornblom) writes:
|>
|>If you must have the same addresses between the processes (which is nice for
|>pointers and stuff) I'd pick some high constant address, say 0x[48c]0000000
|>or so that isn't likely to map onto anything on the architectures
you're using.
|>
I was working on a project with a couple of people last summer where we
had to use shared memory segments and processes had to exchange pointers.
We decided is just wasn't worth it to take chances on a hardcoded address
that might fail on any particular run because the kernel couldn't attach
the segment at the address specified. So we just did all the pointer
exchanging in terms of offsets from the base address of the segment
and let each individual process convert between offsets and virtual
addresses. It's a little tedious at most (like when you're sharing
linked lists), but the added flexibility and reliability is worth
the effort, IMHO.
==================
Chris Volpe
G.E. Corporate R&D
volpecr@crd.ge.com
-----------------------------
From: Warren Tucker <wht@n4hgf.mt-park.ga.us>
Subject: Re: shmat() system call?
Date: 16 Aug 90 19:15:40 GMT
To: unix-wizards@sem.brl.mil
In article <THOMAS.90Aug16123252@uplog.uplog.se> thomas@uplog.se (Thomas Tornblom) writes:
>In article <187@n4hgf.Mt-Park.GA.US> wht@n4hgf.Mt-Park.GA.US (Warren Tucker) writes:
>
> In article <27@astph.UUCP> jeff@astph.UUCP (8592x2) writes:
> To be sure, specify the attach address, regardless of what the FM says.
>This is not guaranteed to work. Typically the kernel allocates the addresses
>depending of the memory layout of the running process.
In all of the implementations I have used, the kernel performs this
optimzation. And of course, it has been working me for 4 years.
-----------------------------------------------------------------------
Warren Tucker, TuckerWare gatech!n4hgf!wht or wht@n4hgf.Mt-Park.GA.US
"Tell the moon; don't tell the March Hare: He is here. Do look around."
-----------------------------
From: Warren Tucker <wht@n4hgf.mt-park.ga.us>
Subject: Re: shmat() system call?
Date: 16 Aug 90 19:17:35 GMT
To: unix-wizards@sem.brl.mil
In article <12638@hydra.gatech.EDU> gt0178a@prism.gatech.EDU (BURNS,JIM) writes:
>in article <187@n4hgf.Mt-Park.GA.US>, wht@n4hgf.Mt-Park.GA.US (Warren Tucker) says:
>< In article <27@astph.UUCP> jeff@astph.UUCP (8592x2) writes:
>< To be sure, specify the attach address, regardless of what the FM says.
>< Make a small program that passes 0 for the address and see what it
>< returns. Then, use that value hardcoded, possibly #defined for each
>< arcitecture you plan to run the program on.
>
>What if yours is not the only application creating and deleting shared
>memory segments? Are you saying you always get the same address?
Yes, in a virtual system where the shmat'd address is virtual.
-----------------------------------------------------------------------
Warren Tucker, TuckerWare gatech!n4hgf!wht or wht@n4hgf.Mt-Park.GA.US
"Tell the moon; don't tell the March Hare: He is here. Do look around."
-----------------------------
From: Suu Quan <quan@hpcc01.hp.com>
Subject: Re: shmat() system call?
Date: 16 Aug 90 19:39:15 GMT
To: unix-wizards@sem.brl.mil
/ hpcc01:comp.unix.wizards / jeff@astph.UUCP (8592x2) / 1:11 pm Aug 15, 1990 /
>
>Question concerning the shared memory attach call:
>
>I need to know if additional attaches by other processes will be
>guaranteed to return the same address as that the first process
>was returned. I am aware that you can request a particular address,
>but why bother communicating that information between the processes
>if the same address is returned anyway? I would appreciate any
>answers or direction to documentation.
In spite of other positive answers, the real answer is NO.
The exactly same program, run on different kernels, will most probably
result in different attached address. The attached address depends on
too many different kernel parameters to discuss here in a few lines.
On the other hand, if you want to request a particular address, the down
side of it is that you don't know whether any other applications has used
that segment of address or not. This practice is definitely not recommended.
-----------------------------
From: Randolph Gary Smith <ut-emx!gary@emx.utexas.edu>
Subject: UNIX System Administration/Programming Positions Available
Keywords: UNIX,Mach,MIMD,SIMD,kernel,UNICOS,CONVEX,SunOS
Date: 16 Aug 90 12:52:54 GMT
Sender: fpst@hubcap.clemson.edu
Approved: parallel@hubcap.clemson.edu
To: unix-wizards@sem.brl.mil
Following are two Senior Operating System Specialist job positions currently
available at The University of Texas System Center for High Performance Com-
puting located in northwest Austin, Texas. Instructions for applying follow
the job descriptions.
------------------------------------------------------------------------------
Position 1: Senior Operating System Specialist
Posting Number: 0-08-01-07-9365
Monthly Salary: $3017 or more
Date Available: 8/8/90
40 hours/week; work hours flexible
Required Qualifications:
Bachelor's degree and five years of programming or systems analysis
experience, of which two years are in operating systems programming;
or high school graduation or equivalent and nine years of programming
or systems analysis experience, of which two years are in operating
systems programming
Initial Qualifications:
Extensive experience as a system administrator for large-scale UNIX
production system(s). Experience in coding in C an FORTRAN. Expe-
rience with computer networking concepts, including experience with
Sun's NFS, Apollo's NCS, and the lower-level protocols on which they
are built.
Preferred Qualifications:
Knowledge of the fundamental algorithms and data structures implemen-
ting the System V UNIX operating system or the 4.2/4.3 BSD UNIX ope-
rating system, including the file subsystem and process control sub-
system of the kernel. Understanding of the kernel system call inter-
face to user-level processes. Experience with the CRAY UNICOS, CONVEX
UNIX, and SunOS UNIX systems at the system administration and develop-
ment levels. Experience with computer networking administration.
Thorough knowledge and understanding of computer architecture.
Job Duties:
To be explained during interview.
-------------------------------------------------------------------------------
Position 2: Senior Operating System Specialist
Posting Number: 0-08-09-02-9365
Monthly Salary: $3017 or more
Date Available: 9/1/90
40 hours/week; work hours flexible
Required Qualifications:
Bachelor's degree and five years of programming or systems analysis
experience, of which two years are in operating systems programming;
or high school graduation or equivalent and nine years of programming
or systems analysis experience, of which two years are in operating
systems programming
Initial Qualifications:
Extensive experience as a system administrator and resource scheduling
and accounting software developer for UNIX and/or Mach systems. Under-
standing of the fundamental opportunities and limitations in moderately
to massively parallel SIMD and MIMD computer systems.
Preferred Qualifications :
Extensive experience with systems software development on massively
parallel SIMD and MIMD computer systems in a distributed computing
environment. Familiarity with architectural details of most massively
parallel SIMD/MIMD distributed- and shared-memory computer systems.
Bachelor's degree in computer science or engineering.
Job Duties:
To be explained during interview.
-------------------------------------------------------------------------------
If you are interested in either position, send a current resume to:
Janet McCord
UT System CHPC
Balcones Research Center
10100 Burnet Rd
Austin, TX 78758-4497
Telephone: 512/471-2418
FAX: 512/471-2445
email: jnet@hermes.chpc.utexas.edu
-----------------------------
From: Bertrand Meyer <bertrand@eiffel.uucp>
Subject: Re: Vi fails on a Sun-4
Keywords: Illegal instruction
Date: 16 Aug 90 17:23:50 GMT
To: unix-wizards@sem.brl.mil
In the article referenced above I mentioned a problem
I was having with vi under csh, failing in inexplicable
ways on a Sun-4 running 4.0.
Many thanks to the several people who responded overnight
and allowed me to correct the problem. For the benefit
of others, here is one of the responses by Nick W. Holloway,
I believe from the University of Warwick:
> This is a bug with SunOS 4.0 (even up to 4.0.3). If the size of your
> environment and the arguments passed to vi are of a magic size, then vi
> will core dump with an illegal instruction. It is not unique to vi, it
> just happens that it occurs frequently with vi. If you have access to
> back issues of sunspots, have a look at the message in Volume 7, Issue
> 26, Subject "Obscure SunOS Bug". This particular bug is fixed in 4.1.
>
> I imagine the reason that it fails differently in different windows is
> that the environment is different sizes. To see this, try using the
> command 'printenv | wc -c'.
>
> The workaround is to just put some junk environment variables in your
> environment to take it over this magic number, or remove some to take
> it under.
The workaround suggested by Mr. Holloway (and several
others in essentially equivalent terms) does work so far
for me.
Thank you very much.
--
-- Bertrand Meyer
bertrand@eiffel.com
-----------------------------
From: Randolph Langley <langley@ds1.scri.fsu.edu>
Subject: Re: Checkpoint/Restart (was "no subject - file transmission")
Date: 16 Aug 90 21:29:15 GMT
Sender: news@sun13.scri.fsu.edu
To: unix-wizards@sem.brl.mil
There is a paper, "Job and Process Recovery In A UNIX-based Operating
System", by Brent Kingsbury and John Kline, that talks about UNICOS's
checkpointing/restarting capabilities. It is available in the Cray
documentation distribution, and I would guess directly from Cray.
I also note that the authors have e-mail addresses: they are
brent@yafs.cray.com and jtk@hall.cray.com.
rdl
-----------------------------
From: Guy Harris <guy@auspex.auspex.com>
Subject: Re: Another "why won't this work" program
Date: 16 Aug 90 19:35:50 GMT
To: unix-wizards@sem.brl.mil
"BKEHOE@widener" isn't a very usable email address, and the Path: line
ended with "news", so I was unable to mail this. Methinks you should
have a talk with your mail or netnews administrator, asking them to fix
the From: line on outgoing postings....
>/*
> * This is being run on a Sun SS1 under 4.0.3.
> * Theoretically, according to the Design & Implementation of 4.3BSD Unix,
> * this should print out the ascii version of each process's current
> * directory...instead, it chokes on u->u_cwd->cw_dir, which is in the
> * u struct in sys/user.h .. any help, suggestions, etc would be greatly
> * appreciated.
Well, actually, 4.3BSD UNIX doesn't *have* a "u_cwd" member of the "u"
structure, so I'd hope that the BSD book *doesn't* suggest that it should
work. That field is a SunOS-ism, introduced as part of the C2 security
stuff so that the auditing code can get the full pathname of a file.
> while ((proc = kvm_nextproc (kd)))
> if (proc->p_stat != SZOMB && proc->p_uid) {
> if (!(user = kvm_getu(kd, proc)))
> continue;
> (void) printf("%s\n", (getpwuid(proc->p_uid))->pw_name);
Well, you probably want to call "getpwuid()" and store the result
somewhere, and then check if it's NULL, before using it; it may not be
*likely* to fail, but it *can* fail.
>/* Curtains & Slow Music */
> (void) printf("%s\n", user->u_cwd->cw_dir);
>/* It dies, but the user structure's fine (printing user->u_comm works); I
> stepped thru it with gdb & discovered that the pointer user->u_cwd
> is off in never-never-land; is it a valid entry in the user structure? */
Do you mean "is 'u_cwd' a valid entry in the user structure?" Well,
maybe. I'm not sure if it's kept up-to-date if you haven't configured
the C2 security stuff into your kernel (SYSAUDIT).
However, even if it *is* kept up-to-date, it doesn't quite point into
user-mode data, obviously. You'll have to grab the pointer value from
"u_cwd" and use "kvm_read()" to read it from the *kernel's* address space
into a private copy. Then, once you've done that, bear in mind that the
"cw_dir" and "cw_root" members of the structure pointed to by "u_cwd"
are *themselves* pointers into the kernel's address space, and read the
strings to which they point using "kvm_read()" as well.
Stepping through kernel data structures is more subtle than you might
think. Pointers in kernel data structures *cannot*, in most systems,
simply be dereferenced; even if the kernel-mode and user-mode address
spaces are common, the kernel data is probably read-protected (for
obvious reasons!).
-----------------------------
From: Peter da Silva <peter@ficc.ferranti.com>
Subject: Re: Is HDB locking safe?
Date: 16 Aug 90 19:49:10 GMT
To: unix-wizards@sem.brl.mil
In article <4024@rtifs1.UUCP> trt@rti.rti.org (Thomas Truscott) writes:
> (a) A "sleep(1);" is not enough to avoid a race on a very busy system.
No sleep is ever enough. The system could simply be busier than you ever
imagined. You don't solve a race problem by narrowing the window: try
checking the return value of the "unlink": that's the point of failure.
--
Peter da Silva. `-_-'
+1 713 274 5180. 'U`
peter@ferranti.com (currently not working)
peter@hackercorp.com
-----------------------------
From: John Palmer <jpp@ddmi.com>
Subject: Problems with DIGIBOARD PC/4
Date: 17 Aug 90 00:28:27 GMT
Followup-To: comp.unix.xenix
To: unix-wizards@sem.brl.mil
I'm running SCO Xenix 2.3.2 on a AT clone (386/20MHz) and I have a
DIGIBOARD PC/4 (4 ports, dumb controller chips).
I'm having some problems with this setup:
1> Sometimes, when someone hangs up, the modem is left in such a state
that it will not answer the phone until it is power-cycled. The RD (rcv data)
and SD (send data) lights remain on and the modem will not answer the phone.
2> Many times, output gets garbled, especially right before a read operation.
I have heard that the I/O chips on this board can be replaced by more
"intelligent" chips. Is this the case, and if so, what is the part
number of the intelligent chip.
On a related topic, is there anyway to flush typeahead in Xenix?? I am
using the Xenix equivalent of cbreak() (by setting various flags with
ioctl()). fflush(stdin) doesn't seem to work, although it doesn't return
an error code.
Thanks ahead of time.
jpp@ddmi.com
--
= CAT-TALK Conferencing Network, Prototype Computer Conferencing System =
- 1-800-825-3069, 300/1200/2400/9600 baud, 8/N/1. New users use 'new' -
= as a login id. E-Mail Address: jpp@ThunderCat.COM =
- <<<Redistribution to GEnie PROHIBITED!!!>>>> -
-----------------------------
End of UNIX-WIZARDS Digest
**************************