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46 lines
1.0 KiB
Plaintext
46 lines
1.0 KiB
Plaintext
4 years ago
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#!/usr/bin/perl -w
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use strict;
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# $Id: flock-test,v 1.1 2000/11/01 22:41:34 lenzo Exp $
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#use sigtrap qw(die normal-signals);
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use Fcntl ':flock';
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use POSIX 'EWOULDBLOCK';
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(my $Me = $0) =~ s-.*/--;
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$| = 1;
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@ARGV == 2 or die "usage: $Me file <sh|ex|nbsh|nbex>";
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my ($file, $type) = @ARGV;
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my $no_block = $type =~ s/^nb//;
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my $bits = $type eq 'sh' ? LOCK_SH
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: $type eq 'ex' ? LOCK_EX
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: die "$Me: unknown lock type $type\n";
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$type = 'LOCK_' . uc $type;
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open FH, "+<$file" or die "$Me: can't read $file: $!\n";
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if (flock FH, $bits | LOCK_NB) {
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print "Locked $file with type $type, sleeping...";
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}
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else {
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$! == EWOULDBLOCK
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or die "$Me: can't flock($file, $type | LOCK_NB): $!\n";
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$no_block and die "$Me: can't immediately lock $file with type $type\n";
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print "Blocking waiting for $type lock on $file...";
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flock FH, $bits
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or die "$Me: can't flock($file, $type): $!\n";
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print "locked, sleeping...";
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}
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sleep;
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#END {
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# if ($locked) {
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# flock FH, LOCK_UN or die "$Me: can't unlock $file: $!\n";
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# }
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#}
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