User::Utmp

Copyright © 2006 Michael Piotrowski.  All Rights Reserved.

This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.

Description
-----------

This module provides a Perl interface to utmpx- and utmp-style
databases on UNIX systems, the most important being "the utmpx file"
(typically found at /var/run/utmpx, /etc/utmpx or a similar location),
which provides information about users currently logged in.  There is
also support for writing records to utmpx and utmp files.  For further
details see the POD documentation embedded in the file Utmp.pm, which
will also be installed as User::Utmp(3) manpage, and the example.pl
script.

Prerequisites
-------------

Your system should provide a utmpx implementation compliant with the
Single UNIX Specification or (for utmp) setutent(), getutent(), and
endutent() functions compliant with SVID2.

Hint files are provided for AIX, HP-UX, Linux, NetBSD and Solaris.  If
you're using a system for which there is no hint file, User::Utmp will
be built with basic utmp support, and, if the _XOPEN_UNIX macro is
defined, with basic utmpx support.  If you want to use additional
fields provided by your system's implementation, you'll have to define
the appropriate flags.

Portability note
----------------

Unfortunately, the contents of the utmp structure are highly
system-dependent, making multi-platform support difficult.

Utmpx is formally standardized, but the definition still leaves some
details to the implementation; most vendors also provide extensions.

Therefore User::Utmp uses hint files (see the hints directory and the
ExtUtils::MakeMaker man page) to control the inclusion of
system-dependent code.  Note that the Linux hint file enables support
for the ut_host and ut_addr fields; these fields exist on the system I
tested it, which is fairly recent.  Older versions of Linux seem to
have much more limited Utmp implementations.

Building the module
-------------------

The module can be built using this sequence of commands:

    perl Makefile.PL
    make
    make test

Besides testing if the module is loadable, "make test" runs a number
of other tests.  For example, it checks if a utmp record matching the
current user and tty can be found.  If utmpx is available, the same
test is also done using utmpx functions.  I *think* this is pretty
portable, but if it fails, it might be because that the assumptions
made by the test do not apply to your system, not because User::Utmp
doesn't work.

I'd appreciate any ideas for portable tests.

Also included is the script example.pl, which can be used for further
testing.

Installation
------------

    make install

History
-------

User::Utmp was developed as a quick solution for a project at hand.
It's therefore a straightforward translation of the C interface to
Perl; originally it provided only two functions (getut() and
getutx()), now it covers the standard utmpx interface, the traditional
utmp interface, and some vendor extensions.

Feedback
--------

This version of User::Utmp was tested on HP-UX 11.00, Linux 2.4.20 and
2.6.14, NetBSD 3.0, and Solaris 9.  If you are building the module on
another platform I'd appreciate a note about how you got on.

Michael Piotrowski <mxp@dynalabs.de>