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.
use IPC::Locker; # ... my $lock = IPC::Locker->lock(host=>'example.std.com'); # ... Critical section ... $lock->unlock;
Build and Install the Package
Install from CPAN:
cpan install IPC::Locker
Or, build from sources:
# Obtain distribution kit git clone firstname.lastname@example.org: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
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.
If you are using Nagios http://www.nagios.org, sample scripts to check the daemons are included in the nagios subdirectory.
IPC::Locker provides the following programs/packages:
lockerd is the daemon that supports IPC::Locker. See
man lockerd after installation.
IPC::PidStat is a Perl package which answers the question, "is pid X running on host Y?". See
man IPC::PidStat after installation.
pidstat is a program which answers the question, "is pid X running on host Y?". See
man pidstat after installation.
pidstat is the daemon that supports
man pidstatd after installation.
pidwatch is a program which starts other programs, and kill that program when another job exists. See
man pidwatch after installation.
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_pidstatd are Nagios plugins to check
pidstatd. See the Nagios documentation at https://www.nagios.org for information on installing plugins.
This package is Copyright 1999-2019 by Wilson Snyder <email@example.com>.
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.