| <?xml version='1.0'?> <!--*-nxml-*--> |
| <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" |
| "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
| |
| <!-- |
| This file is part of systemd. |
| |
| Copyright 2010 Lennart Poettering |
| |
| systemd is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| systemd is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| --> |
| |
| <refentry id="sd-login" conditional='HAVE_PAM' |
| xmlns:xi="http://www.w3.org/2001/XInclude"> |
| |
| <refentryinfo> |
| <title>sd-login</title> |
| <productname>systemd</productname> |
| |
| <authorgroup> |
| <author> |
| <contrib>Developer</contrib> |
| <firstname>Lennart</firstname> |
| <surname>Poettering</surname> |
| <email>lennart@poettering.net</email> |
| </author> |
| </authorgroup> |
| </refentryinfo> |
| |
| <refmeta> |
| <refentrytitle>sd-login</refentrytitle> |
| <manvolnum>3</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>sd-login</refname> |
| <refpurpose>APIs for |
| tracking logins</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <funcsynopsis> |
| <funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo> |
| </funcsynopsis> |
| |
| <cmdsynopsis> |
| <command>pkg-config --cflags --libs libsystemd</command> |
| </cmdsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para><filename>sd-login.h</filename> provides APIs to introspect |
| and monitor seat, login session and user status information on the |
| local system. </para> |
| |
| <para>See <ulink |
| url="https://www.freedesktop.org/wiki/Software/systemd/multiseat">Multi-Seat |
| on Linux</ulink> for an introduction into multi-seat support on |
| Linux, the background for this set of APIs.</para> |
| |
| <para>Note that these APIs only allow purely passive access and |
| monitoring of seats, sessions and users. To actively make changes |
| to the seat configuration, terminate login sessions, or switch |
| session on a seat you need to utilize the D-Bus API of |
| systemd-logind, instead.</para> |
| |
| <para>These functions synchronously access data in |
| <filename>/proc</filename>, <filename>/sys/fs/cgroup</filename> |
| and <filename>/run</filename>. All of these are virtual file |
| systems, hence the runtime cost of the accesses is relatively |
| cheap.</para> |
| |
| <para>It is possible (and often a very good choice) to mix calls |
| to the synchronous interface of <filename>sd-login.h</filename> |
| with the asynchronous D-Bus interface of systemd-logind. However, |
| if this is done you need to think a bit about possible races since |
| the stream of events from D-Bus and from |
| <filename>sd-login.h</filename> interfaces such as the login |
| monitor are asynchronous and not ordered against each |
| other.</para> |
| |
| <para>If the functions return string arrays, these are generally |
| <constant>NULL</constant> terminated and need to be freed by the |
| caller with the libc |
| <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| call after use, including the strings referenced therein. |
| Similarly, individual strings returned need to be freed, as |
| well.</para> |
| |
| <para>As a special exception, instead of an empty string array |
| <constant>NULL</constant> may be returned, which should be treated |
| equivalent to an empty string array.</para> |
| |
| <para>See |
| <citerefentry><refentrytitle>sd_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_uid_get_state</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_seat_get_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_login_monitor_new</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| for more information about the functions |
| implemented.</para> |
| </refsect1> |
| |
| <xi:include href="libsystemd-pkgconfig.xml" /> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para> |
| <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_uid_get_state</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_seat_get_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd_login_monitor_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |