How to abort Postscript infinite loop jobs in LaserJet pri..

Archived from groups: comp.lang.postscript,comp.periphs.printers (More info?)

Antti Louko wrote:
> Hello,
>
> Although this is mainly HP Laserjet issue, this is also a Postscript
> issue as infinite loops are easiest to do in PS.
>
> If I send the following PS job to a LaserJet printer (LJ2420DN over
> JetDirect card or embedded interface):
>
> %!
> /n 0 def { n (................) cvs == flush /n n 1 add def } loop
>
> or this one
>
> %!
> { } loop
>
> which doesn't output anything back,
>
> I have found no way to abort the job either using TCP connection, PJL,
> Web interface SNMP. Even STOP button in the front panel doesn't seem
> to do anything.
>
> PS related rambling:
>
> Laserjet PS doesn't seem to have /JobTimeout paramater which could be
> used to work around naive infinite loops where job doesn't change the
> JobTimeout on purpose.
>
> ctl-D, ctl-C or <ESC>%-12345X don't abort the job either, not over the
> original channel or a new TCP connection.
>
> Any suggestions?


Stop doing that.

Archived from groups: comp.lang.postscript,comp.periphs.printers (More info?)

Antti Louko wrote:
> Hello,
>
> [infinite loops in PS-files are evil]
>
> Any suggestions?

Hi Antti Louko,

if you are working under LINUX/UNIX then maybe this can help you:

1.) Set an alias for the lpr command for all users
$> alias lpr="my_lpr"

2.) Put this small program 'new_lpr' in an accessible binary directory:


--------------------------------------8<--------------------------------
#!/bin/sh
# $Id: new_lpr $
# to avoid sending corrupt PS-files to the printer

# look it up for yourself, where your commands are
alias PS2PS="/usr/bin/ps2ps"
alias LPR="/usr/bin/lpr"
alias RM="/bin/rm -f"

# insert starting options here (default printer etc.)
OPTIONS=""

while true
do
case "$1" in
-*) OPTIONS="$OPTIONS $1" ;;
*) break ;;
esac
shift
done

if [ $# -ne 1 ]; then
echo "Usage: `basename $0` [-PPrinter] [...] output.ps" 1>&2
exit 1
fi

PS2PS $1 /tmp/$1_temp
LPR $OPTIONS /tmp/$1_temp
RM /tmp/$1_temp
-------------------------------------->8--------------------------------

If anyone is trying to print with the 'lpr'-command, then 'ps2ps' create
a new ps-file (default is PSLanguageLevel 2) from the original ps-file.
In the case, where the original ps-file contain an infinite loop or
other bad things, there is no new ps-file. And of course, there is no
print-job too.

No bad print-jobs, no more problems!

Hope that helps,
Greetings,
Oliver

Archived from groups: comp.lang.postscript,comp.periphs.printers (More info?)

Oliver Bendix <oliver@chaos.gwdg.de> writes:

> Antti Louko wrote:
> > Hello,
> > [infinite loops in PS-files are evil]

> If anyone is trying to print with the 'lpr'-command, then 'ps2ps' create
> a new ps-file (default is PSLanguageLevel 2) from the original ps-file.
> In the case, where the original ps-file contain an infinite loop or
> other bad things, there is no new ps-file. And of course, there is no
> print-job too.

That is one way to handle the issue but it seems quite silly to run
same job twice just to check the evilness.

I am still looking a way to abort jobs in LJ.

Archived from groups: comp.lang.postscript,comp.periphs.printers (More info?)

Antti Louko <alo@iki.fi.invalid> writes:

> ctl-D, ctl-C or <ESC>%-12345X don't abort the job either, not over the
> original channel or a new TCP connection.

I experimented a little more. It seems that pressing "Cancel" button
in the physical panel or in the web interface really does nothing
_until next page is being printed_. At that moment, an interrupt
error is executed in PS environment.

It would make sense to cause interrupt immediately when cancel is
executed.

I try to put this through HP support process, but I am not too
optimistic with that accomplishing anything. If there is an HP
printer person reading this, we may move this to mail correspondance
and try to do something.