Article 4820 of comp.lang.perl:

Article 4820 of comp.lang.perl:
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From: [email protected] (Michael T.Y. McNamara)
Subject: Re: perl's equiv of csh 'limit'?
In-Reply-To: [email protected]'s message of Tue, 3 Aug 1993 16:07:02 GMT
Message-ID: <[email protected]>
Sender: [email protected]
Nntp-Posting-Host: rhea
Reply-To: [email protected]
Organization: Chronologic Simulation
References: <[email protected]>
Date: Thu, 5 Aug 1993 21:56:38 GMT
Lines: 86

>>>>> On Tue, 3 Aug 1993 16:07:02 GMT, [email protected] (Lee Qiao ~{GG@hT*~}) said:
> Is there a Perl equivalent of csh's 'limit' command
> (or the 'vlimit' call in C)? Currently I am using the
> following,
> open(STUFF, "/bin/csh -f -c 'limit cputime 150; <some process>|'");
> which seems a little inefficient to me.
> If you have any ideas please reply by e-mail. Thank you!
Did so, but for the rest of you:

Snipped out of my verilog compiler regression perl driver, which wants
to arrange so that children generate no corefiles, don't run into
"arbitrarily small" stack limits, and don't infinate loop:

To get a file handle from which you could read the output, you will
need to much about in the spawnntime to have the parent open a pipe
before the fork and have the child hook it's stdout to the write piece
of the pipe... Left as an exercise...

require 'syscall.ph';
require 'sys/resource.ph'; # note h2ph doesn't always win on this one
# -- hand editing may be necessary

# Arrange so no core files are generated
$coresize = pack("i2",0,0);
syscall(&SYS_setrlimit, &RLIMIT_CORE, $coresize);

# Make stack size large
$stacksize = pack("i2",1024*1024*4,1024*1024*4);
syscall(&SYS_setrlimit, &RLIMIT_STACK, $stacksize);

..

foreach (test...)
@cmpl_time = &spawnntime("$compile_cmd > $output 2>&1",3000);
printf "cmpl: %.2f ",$cmpl_time[2];
...
@run_time = &spawnntime("$run_cmd > $output 2>&1",3000);
printf "run: %.2f ",$run_time[2];

}

sub spawnntime {
local($cmd,$limittime) = @_;
local(@start,@end,@diff);
@start = times;
FORK: {
if ($child_pid = fork ) {
waitpid($child_pid,0); # Parent - wait for child to finish
&report_err($cmd) if ( $? );
@end = times;
$diff[0] = $end[0] - $start[0];
$diff[1] = $end[1] - $start[1];
$diff[2] = $end[2] - $start[2];
$diff[3] = $end[3] - $start[3];
$child_pid = 0;
return @diff;

} elsif (defined $child_pid) {
# Child - run argument
if( $limittime) {
@so_far = times();
$timelimit = pack("i2", $limittime+$so_far[0], $limittime*2+$so_far[0]);
syscall(&SYS_setrlimit, &RLIMIT_CPU, $timelimit);
}
exec("$cmd");
&report_err($cmd) if ( $? );
exit;

} elsif ( $! =~ /No more process/ ) {
# EAGAIN, presumably recoverable...
sleep 5;
redo FORK;
} else {
die "Can not fork: $!\n";
}
}
}

--
Michael T.Y. McNamara 1+(415) 965-3312
,------. 1+(415) 965-2705 FAX
|CHRONO|LOGIC SIMULATION [email protected]
`------' {yes, company has new logo.. *sigh*}