# <@LICENSE>
# Licensed to the Apache Software Foundation (ASF) under one or more
# contributor license agreements. See the NOTICE file distributed with
# this work for additional information regarding copyright ownership.
# The ASF licenses this file to you under the Apache License, Version 2.0
# (the "License"); you may not use this file except in compliance with
# the License. You may obtain a copy of the License at:
#
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# </@LICENSE>
use strict;
# use bytes;
use re 'taint';
use Fcntl;
our @ISA = qw(Mail::SpamAssassin::Locker);
###########################################################################
sub new {
my $class = shift;
my $self = $class->SUPER::new(@_);
$self;
}
###########################################################################
use constant LOCK_MAX_AGE => 600; # seconds
sub safe_lock {
my ($self, $path, $max_retries, $mode) = @_;
my @stat;
$max_retries ||= 30;
# $mode is ignored on win32
my $lock_file = "$path.lock";
if (-e $lock_file && -M $lock_file > (LOCK_MAX_AGE / 86400)) {
dbg("locker: safe_lock: breaking stale lock: $lock_file");
unlink($lock_file)
or warn "locker: safe_lock: unlink of lock file $lock_file failed: $!\n";
}
for (my $retries = 0; $retries < $max_retries; $retries++) {
if ($retries > 0) {
sleep(1);
# TODO: $self->jittery_one_second_sleep();?
}
dbg("locker: safe_lock: trying to get lock on $path with $retries retries");
if (!defined sysopen(LOCKFILE, $lock_file, O_RDWR|O_CREAT|O_EXCL)) {
dbg("locker: safe_lock: failed to create lock tmpfile $lock_file: $!");
} else {
dbg("locker: safe_lock: link to $lock_file: sysopen ok");
close(LOCKFILE) or warn "error closing a lock file: $!";
return 1;
}
my @stat = stat($lock_file);
@stat or dbg("locker: error accessing $lock_file: $!");
# check age of lockfile ctime
my $age = ($#stat < 11 ? undef : $stat[10]);
if ((!defined($age) && $retries > $max_retries / 2) ||
(defined($age) && (time - $age > LOCK_MAX_AGE)))
{
dbg("locker: safe_lock: breaking stale lock: $lock_file");
unlink($lock_file)
or warn "locker: safe_lock: unlink of lock file $lock_file failed: $!\n";
}
}
return 0;
}
###########################################################################
sub safe_unlock {
my ($self, $path) = @_;
unlink("$path.lock")
or warn "locker: safe_unlock: unlink failed: $path.lock\n";
dbg("locker: safe_unlock: unlink $path.lock");
}
###########################################################################
sub refresh_lock {
my($self, $path) = @_;
return unless $path;
# this could arguably read the lock and make sure the same process
# owns it, but this shouldn't, in theory, be an issue.
utime time, time, "$path.lock";
dbg("locker: refresh_lock: refresh $path.lock");
}
###########################################################################
1;