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SUMMARY

IPC::Locker provides a server for locks and a Perl package for clients to access that server. The result is that clients can access named locks on a Internet wide basis, solving critical section problems without the mess of NFS or other file locking techniques.

The latest version is available from CPAN and from https://www.veripool.org/ipc-locker.

EXAMPLE

use IPC::Locker;
# ...
my $lock = IPC::Locker->lock(host=>'example.std.com');
# ... Critical section ...
$lock->unlock;

INSTALLATION

Build and Install the Package

Install from CPAN:

cpan install IPC::Locker

Or, build from sources:

# Obtain distribution kit
git clone git@github.com:veripool/IPC-Locker.git
# Build
cd IPC-Locker
git pull
perl Makefile.PL
make
make test
make install

Install the Daemons

You may wish to install lockerd and pidstatd in a init.rc file so that it is run at system startup. Depending on your distribution, you may be able to just:

cp init.d/lockerd   /etc/init.d/lockerd  # On one server only
cp init.d/pidstatd  /etc/init.d/pidstatd  # On all machines

Edit paths in above to point to /usr/bin instead of /usr/local/bin, if needed.

service lockerd start  # On one server only
service pidstatd start  # On all machines
chkconfig lockerd on  # On one server only
chkconfig pidstatd on  # On all machines

If you get "This account is currently not available." you need to change the daemon account from a shell of /sbin/nologin to /sbin/bash.

Nagios

If you are using Nagios http://www.nagios.org, sample scripts to check the daemons are included in the nagios subdirectory.

DOCUMENTATION

IPC::Locker provides the following programs/packages:

lockerd

lockerd is the daemon that supports IPC::Locker. See man lockerd after installation.

IPC::PidStat

IPC::PidStat is a Perl package which answers the question, "is pid X running on host Y?". See man IPC::PidStat after installation.

pidstat

pidstat is a program which answers the question, "is pid X running on host Y?". See man pidstat after installation.

pidstatd

pidstat is the daemon that supports IPC::PidStat and pidstat. See man pidstatd after installation.

pidwatch

pidwatch is a program which starts other programs, and kill that program when another job exists. See man pidwatch after installation.

uriexec

uriexec is a simple wrapper which allows executing a command which is quoted using URI escapes. This prevents layered shells from interpreting special characters. See man uriexec after installation.

check_lockerd and check_pidstatd

check_lockerd and check_pidstatd are Nagios plugins to check lockerd and pidstatd. See the Nagios documentation at https://www.nagios.org for information on installing plugins.

LICENSE

This package is Copyright 1999-2019 by Wilson Snyder <wsnyder@wsnyder.org>.

This program is free software; you can redistribute it and/or modify it under the terms of either the GNU Lesser General Public License Version 3 or the Perl Artistic License Version 2.0. This code is provided with no warranty of any kind, and is used entirely at your own risk.