0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
12b42c76672a66c2d4ea7212c14f8f1b5a62b78dTom Gundersen "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering This file is part of systemd.
0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering Copyright 2010 Lennart Poettering
0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering systemd is free software; you can redistribute it and/or modify it
5430f7f2bc7330f3088b894166bf3524a067e3d8Lennart Poettering under the terms of the GNU Lesser General Public License as published by
5430f7f2bc7330f3088b894166bf3524a067e3d8Lennart Poettering the Free Software Foundation; either version 2.1 of the License, or
0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering (at your option) any later version.
0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering systemd is distributed in the hope that it will be useful, but
0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering WITHOUT ANY WARRANTY; without even the implied warranty of
0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
5430f7f2bc7330f3088b894166bf3524a067e3d8Lennart Poettering Lesser General Public License for more details.
5430f7f2bc7330f3088b894166bf3524a067e3d8Lennart Poettering You should have received a copy of the GNU Lesser General Public License
0b3b020a178cf3b957fed627de13c895773995ecLennart Poettering along with systemd; If not, see <http://www.gnu.org/licenses/>.
56ba3c78ae35065064c4289a0c8e22a81256af20Zbigniew Jędrzejewski-Szmek<refentry id="sd_get_seats" conditional='HAVE_PAM'>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <productname>systemd</productname>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <email>lennart@poettering.net</email>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <refentrytitle>sd_get_seats</refentrytitle>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <refname>sd_get_sessions</refname>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <refname>sd_get_machine_names</refname>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <refpurpose>Determine available seats, sessions, logged in users and virtual machines/containers</refpurpose>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <refsynopsisdiv>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <funcdef>int <function>sd_get_seats</function></funcdef>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <paramdef>char ***<parameter>seats</parameter></paramdef>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek </funcprototype>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <funcdef>int <function>sd_get_sessions</function></funcdef>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <paramdef>char ***<parameter>sessions</parameter></paramdef>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek </funcprototype>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <funcdef>int <function>sd_get_uids</function></funcdef>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <paramdef>uid_t **<parameter>users</parameter></paramdef>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek </funcprototype>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <funcdef>int <function>sd_get_machine_names</function></funcdef>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <paramdef>char ***<parameter>machines</parameter></paramdef>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek </funcprototype>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek </refsynopsisdiv>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <para><function>sd_get_seats()</function> may be used to determine
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek all currently available local seats. Returns a
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <constant>NULL</constant> terminated array of seat identifiers.
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek The returned array and all strings it references need to be freed
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek call after use. Note that instead of an empty array
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <constant>NULL</constant> may be returned and should be considered
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek equivalent to an empty array.</para>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <para>Similarly, <function>sd_get_sessions()</function> may be
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek used to determine all current login sessions.</para>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <para>Similarly, <function>sd_get_uids()</function> may be used to
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek determine all Unix users who currently have login sessions.</para>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <para>Similarly, <function>sd_get_machine_names()</function> may
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek be used to determine all current virtual machines and containers
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek on the system.</para>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <para>Note that the returned lists are not sorted and in an
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek undefined order.</para>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <para>On success, <function>sd_get_seats()</function>,
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <function>sd_get_sessions()</function>,
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <function>sd_get_uids()</function> and
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <function>sd_get_machine_names()</function> return the number of
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek entries in the arrays. On failure, these calls return a negative
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek errno-style error code.</para>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering <para>Returned errors may indicate the following problems:</para>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering <variablelist>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering <varlistentry>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering <term><constant>-EINVAL</constant></term>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering <listitem><para>An input parameter was invalid (out of range,
7ca4155737730ece73ae4b4ac80571005cb99b69Jan Engelhardt or NULL, where that is not accepted).</para></listitem>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering </varlistentry>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering <varlistentry>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering <term><constant>-ENOMEM</constant></term>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering <listitem><para>Memory allocation failed.</para></listitem>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering </varlistentry>
707b66c66381c899d7ef640e158ffdd5bcff4debLennart Poettering </variablelist>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <para>The <function>sd_get_seats()</function>,
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <function>sd_get_sessions()</function>,
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <function>sd_get_uids()</function> and
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <function>sd_get_machine_names()</function> interfaces are
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek available as a shared library, which can be compiled and linked to
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
798d3a524ea57aaf40cb53858aaa45ec702f012dZbigniew Jędrzejewski-Szmek <citerefentry><refentrytitle>sd_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry>