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#!/usr/bin/perl -w
### Written by Rob Brown
### This script is designed to be ran on multiple boxes
### by multiple processes with a high increment number.
### The processes should all compete, but a successful
### test occurs if all of the specified inc's add up to
### the final number in the specified file.
use strict;
use File::NFSLock ();
use Fcntl qw(O_RDWR O_CREAT LOCK_EX);
my $datafile = shift;
my $inc = shift || do {
print "Usage: $0 <filename> <increment>\n";
exit;
};
while ( $inc -- > 0 ) {
my $lock = new File::NFSLock ($datafile, LOCK_EX)
or print "Ouch1\n"; # blocking lock (Exclusive)
sysopen(FH, $datafile, O_RDWR | O_CREAT)
or die "Cannot open [$datafile][$!]";
### read the count and spit it out
my $count = <FH>;
$count ++;
print "[$$] I win with [$count] \r";
seek (FH,0,0);
print FH "$count\n";
close FH;
# $lock leaves scope and unlocks automagically
}
print "\n\n";
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