/usr/share/perl5/Mail/Box/Locker/Flock.pm is in libmail-box-perl 2.099-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 | # Copyrights 2001-2011 by Mark Overmeer.
# For other contributors see ChangeLog.
# See the manual pages for details on the licensing terms.
# Pod stripped from pm file by OODoc 2.00.
use strict;
package Mail::Box::Locker::Flock;
use vars '$VERSION';
$VERSION = '2.099';
use base 'Mail::Box::Locker';
use IO::File;
use Fcntl qw/:DEFAULT :flock/;
use Errno qw/EAGAIN/;
sub name() {'FLOCK'}
sub _try_lock($)
{ my ($self, $file) = @_;
flock $file, LOCK_EX|LOCK_NB;
}
sub _unlock($)
{ my ($self, $file) = @_;
flock $file, LOCK_UN;
delete $self->{MBL_has_lock};
$self;
}
# 'r+' is require under Solaris and AIX, other OSes are satisfied with 'r'.
my $lockfile_access_mode = ($^O eq 'solaris' || $^O eq 'aix') ? 'r+' : 'r';
sub lock()
{ my $self = shift;
my $folder = $self->folder;
if($self->hasLock)
{ $self->log(WARNING => "Folder $folder already flocked.");
return 1;
}
my $filename = $self->filename;
my $file = IO::File->new($filename, $lockfile_access_mode);
unless($file)
{ $self->log(ERROR =>
"Unable to open flock file $filename for $folder: $!");
return 0;
}
my $end = $self->{MBL_timeout} eq 'NOTIMEOUT' ? -1 : $self->{MBL_timeout};
while(1)
{ if($self->_try_lock($file))
{ $self->{MBL_has_lock} = 1;
$self->{MBLF_filehandle} = $file;
return 1;
}
if($! != EAGAIN)
{ $self->log(ERROR =>
"Will never get a flock on $filename for $folder: $!");
last;
}
last unless --$end;
sleep 1;
}
return 0;
}
sub isLocked()
{ my $self = shift;
my $filename = $self->filename;
my $file = IO::File->new($filename, $lockfile_access_mode);
unless($file)
{ $self->log(ERROR =>
"Unable to check lock file $filename for $self->{MBL_folder}: $!");
return 0;
}
$self->_try_lock($file) or return 0;
$self->_unlock($file);
$file->close;
1;
}
sub unlock()
{ my $self = shift;
$self->_unlock(delete $self->{MBLF_filehandle})
if $self->hasLock;
$self;
}
1;
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