Software
skarnet.org

utmps

What is it ?

utmps is an implementation of the utmpx.h family of functions performing user accounting on Unix systems.

Traditionally, utmp functionality is provided by the system's libc. However, not all libcs implement utmp: for instance the musl libc, on Linux, does not. The main reason for it is that utmp functionality is difficult to implement in a secure way; in particular, it is impossible to implement without either running a daemon or allowing arbitrary programs to tamper with user accounting.

utmps is a secure implementation of user accounting, using a daemon as the only authority to manage the utmp and wtmp data; programs running utmp functions are just clients to this daemon.

• An overview of utmps

Installation

Requirements

• A POSIX-compliant system with a standard C development environment
• GNU make, version 3.81 or later
• skalibs version 2.14.4.0 or later. It's a build-time requirement. It's also a run-time requirement if you link against the shared version of the skalibs library.
• s6 version 2.13.2.0 or later. It's a run-time requirement only, to run the utmpd and wtmpd services (and can be done without if you have a suitable replacement for s6-ipcserver).

Licensing

utmps is free software. It is available under the ISC license.

Download

• The current released version of utmps is 0.1.3.1. You can access its checksum here.
• Alternatively, you can checkout a copy of the utmps git repository:

   git clone git://git.skarnet.org/utmps 

• There's also a GitHub mirror of the utmps git repository.

Compilation

• See the enclosed INSTALL file for installation details.

Upgrade notes

• This page lists the differences to be aware of between the previous versions of utmps and the current one.

Reference

Commands

• The utmps-utmpd program
• The utmps-wtmpd program
• The utmps-write program

Libraries

• The utmps library interface
• The utmpx.h library interface is implemented on top of the utmps library.
• The logwtmp() and updwtmpx() functions are also implemented.

utmps discussion

• utmps is discussed on the skaware mailing-list.