1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
# Blocking Exclusive Lock Test
use strict;
use warnings;
use File::Temp qw(tempfile);
use Test::More;
if( $^O eq 'MSWin32' ) {
plan skip_all => 'Tests fail on Win32 due to forking';
}
else {
plan tests => 20+2;
}
use File::NFSLock;
use Fcntl qw(O_CREAT O_RDWR O_RDONLY O_TRUNC LOCK_EX);
# $m simultaneous processes each trying to count to $n
my $m = 20;
my $n = 50;
$| = 1; # Buffer must be autoflushed because of fork() below.
my $datafile = (tempfile 'XXXXXXXXXX')[1];
# Create a blank file
sysopen ( my $fh, $datafile, O_CREAT | O_RDWR | O_TRUNC );
close ($fh);
ok (-e $datafile && !-s _);
for (my $i = 0; $i < $m ; $i++) {
# For each process
if (!fork) {
# Child process need to count to $n
for (my $j = 0; $j < $n ; $j++) {
my $lock = new File::NFSLock {
file => $datafile,
lock_type => LOCK_EX,
};
sysopen(my $fh, $datafile, O_RDWR);
# Read the current value
my $count = <$fh>;
# Increment it
$count ++;
# And put it back
seek ($fh,0,0);
print $fh "$count\n";
close $fh;
}
exit;
}
}
for (my $i = 0; $i < $m ; $i++) {
# Wait until all the children are finished counting
wait;
ok 1;
}
# Load up whatever the file says now
sysopen(my $fh2, $datafile, O_RDONLY);
$_ = <$fh2>;
close $fh2;
chomp;
# It should be $m processes time $n each
is $n*$m, $_;
# Wipe the temporary file
unlink $datafile;
|
