pyutmp 0.2.1

Python UTMP wrapper for Un*x systems

Introduction

The pyutmp module provides a Python-oriented interface to the utmp file on Unix-like operating systems. To paraphrase the Linux Programmer’s Manual page utmp(5), the utmp file allows one to discover information about who is currently using (i.e., is logged into) the system. The utmp file is a series of entries whose structure is typically defined by the utmp.h C header file.

This module provides an read-only interface to the underlying operating system’s C utmp API.

Interface and Usage

The pyutmp module supplies two classes: UtmpFile and Utmp. A UtmpFile object represents the open utmp file; when you iterate over a UtmpFile object, it yields successive Utmp objects. For example:

from pyutmp import UtmpFile
import time

for utmp in UtmpFile():
    # utmp is a Utmp object
    if utmp.ut_user_process:
        print '%s logged in at %s on tty %s' % (utmp.ut_user, time.ctime(utmp.ut_time), utmp.ut_line)

UtmpFile

In addition to the __iter__() generator method, allowing iteration over the contents of the utmp file, the UtmpFile class also provides a rewind() method that permits you to reset the file pointer to the top of the file. See the class documentation for details.

Utmp

The fields of the Utmp class are operating system-dependent. However, they will always include at least the following fields:

Field	Type	Description
ut_user	str	The user associated with the utmp entry, if any.
ut_line	str	The tty or pseudo-tty associated with the entry, if any. In this API, the line will always be the full path to the device.
ut_host	str	The host name associated with the entry, if any.
ut_time	timestamp	The timestamp associated with the entry. This timestamp is in the form returned by time.time() and may be passed directly to methods like time.ctime().
ut_user_process	bool	Whether or not the utmp entry is a user process (as opposed to a reboot or some other system event).

On some operating systems, other fields may be present. For instance, on Linux and Solaris systems (and other System V-derived systems), Utmp also contains the following fields:

Optional Field	Type	Description
ut_type	str	The type of the entry, typically one of the following string values: “RUN_LVL”, “BOOT_TIME”, “NEW_TIME”, “OLD_TIME”, “INIT_PROCESS”, “LOGIN_PROCESS”, “USER_PROCESS”, “DEAD_PROCESS”, “ACCOUNTING”. See the utmp(5) manual page for a description of these values
ut_pid	int	Associated process ID, if any.
ut_id	str	The init(8) ID, or the abbreviated tty name.
ut_exit_code	int	Process exit code, if applicable.
ut_session	int	Session ID, for windowing.
ut_addr	int array	IPv4 address of remote host (if applicable), one octet per array element.

If you’re writing portable code, you should not count on the presence of those attributes–or, at the very least, you should wrap access to them in a try/catch block that catches AttributeError.

Notes

This module has been tested on the following operating systems:

• Ubuntu Linux, version 8.04

• FreeBSD

• Mac OS X 10.4 (Tiger)

• OpenSolaris (2008.05, x86, using the SunStudio 12 compiler suite)

Adding support for other Unix variants should be straightforward.

Restrictions

• Access to the utmp file is read-only. There is no provision for writing to the file.

Copyright and License

This software is released under a BSD license, adapted from <http://opensource.org/licenses/bsd-license.php>

Copyright (c) 2008-2010 Brian M. Clapper. All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.

• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

• Neither the name “clapper.org” nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

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