killing commands in a pipe?

killing commands in a pipe?

[Dominik Vogt]

I have a problem with a shell script:

  #!/usr/bin/zsh
  setopt NOHUP
  some_command_that_never_exits |
  while true; do
    read LINE
    ...
  done

I start the script from another script with

  my_script &

and I try to kill it with

  killall some_command_that_never_exits

The problem is that although some_command_that_never_exits is
killed as expected, the 'while' part of the pipe doesn't exit.
Actually it's worse than that because the zsh running the command
refuses to be killed, even with kill -9. If I unset the NOHUP
option instead:

  unsetopt NOHUP

it works ok. The manpage says this about the (NO)HUP option:

  HUP    Send the HUP signal to running jobs when the shell exits.

So this doesn't explain the behaviour. Shouldn't the pipe exit
completely when the input stream is broken, regardless of the
HUP/NOHUP option?

I am using zsh 3.0.5 u'on a Linux 2.2.5 kernel.

(please cc me, I'm not on the list)

Bye

Dominik ^_^

-- 
Dominik Vogt, Hewlett-Packard GmbH, Dept. BVS
Herrenberger Str.130, 71034 Boeblingen, Germany
phone: 07031/14-4596, fax: 07031/14-3883, dominik_vogt@hp.com

Re: killing commands in a pipe?

[Dominik Vogt]

On Mon, Jun 14, 1999 at 10:17:26AM +0000, schaefer@candle.brasslantern.com wrote:
> On Jun 14, 12:12pm, Dominik Vogt wrote:
> } Subject: killing commands in a pipe?
> }
> } The problem is that although some_command_that_never_exits is
> } killed as expected, the 'while' part of the pipe doesn't exit.
> 
> Try grabbing the patches from ftp://ftp.brasslantern.com/pub/zsh/ to
> build 3.0.6-pre-4, and let me know if the problem persists there.

Yes, the problem is still there. BTW, I must have overlooked this
when I wrote my first mail: the setting of HUP/NOHUP does not matter,
the problem occurs in both cases.

Bye

Dominik ^_^

-- 
Dominik Vogt, Hewlett-Packard GmbH, Dept. BVS
Herrenberger Str.130, 71034 Boeblingen, Germany
phone: 07031/14-4596, fax: 07031/14-3883, dominik_vogt@hp.com

Re: killing commands in a pipe?

[Sven Wischnowsky]

Dominik Vogt wrote:

> On Mon, Jun 14, 1999 at 10:17:26AM +0000, schaefer@candle.brasslantern.com wrote:
> > On Jun 14, 12:12pm, Dominik Vogt wrote:
> > } Subject: killing commands in a pipe?
> > }
> > } The problem is that although some_command_that_never_exits is
> > } killed as expected, the 'while' part of the pipe doesn't exit.
> > 
> > Try grabbing the patches from ftp://ftp.brasslantern.com/pub/zsh/ to
> > build 3.0.6-pre-4, and let me know if the problem persists there.
> 
> Yes, the problem is still there. BTW, I must have overlooked this
> when I wrote my first mail: the setting of HUP/NOHUP does not matter,
> the problem occurs in both cases.

Sorry I didn't try it yesterday...

The problem is that we have all this code in update_job() that handles 
such cases, but only if MONITOR is set -- which it isn't in a script-
shell.

I can only hope that the patch has no negative effects -- it is for
pws-21. I haven't tried it but I think it should also work with
3.0.5-pre-4.

Bye
 Sven

--- os/jobs.c	Mon Jun 14 09:16:19 1999
+++ Src/jobs.c	Tue Jun 15 09:16:27 1999
@@ -240,8 +240,11 @@
 		adjustwinsize(0);
 	    }
 	}
+    } else if (list_pipe && (val & 0200) && inforeground == 1) {
+	breaks = loops;
+	errflag = 1;
+	inerrflush();
     }
-
     if (somestopped && jn->stat & STAT_SUPERJOB)
 	return;
     jn->stat |= (somestopped) ? STAT_CHANGED | STAT_STOPPED :

--
Sven Wischnowsky                         wischnow@informatik.hu-berlin.de