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<?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_session_is_active" conditional='HAVE_PAM'>
<refentryinfo>
<title>sd_session_is_active</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_session_is_active</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_session_is_active</refname>
<refname>sd_session_get_state</refname>
<refname>sd_session_get_uid</refname>
<refname>sd_session_get_seat</refname>
<refname>sd_session_get_service</refname>
<refname>sd_session_get_type</refname>
<refname>sd_session_get_class</refname>
<refname>sd_session_get_display</refname>
<refname>sd_session_get_tty</refname>
<refname>sd_session_get_vt</refname>
<refpurpose>Determine state of a specific session</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_session_is_active</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_state</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>state</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_uid</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>uid_t* <parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_seat</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>seat</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_service</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>service</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_type</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>type</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_class</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>class</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_display</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>display</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_tty</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>tty</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_vt</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>unsigned int* <parameter>vt</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_session_is_active()</function> may
be used to determine whether the session identified by
the specified session identifier is currently active
(i.e. currently in the foreground and available for
user input) or not.</para>
<para><function>sd_session_get_state()</function> may
be used to determine the state of the session
identified by the specified session identifier. The
following states are currently known:
<literal>online</literal> (session logged in, but
session not active, i.e. not in the foreground),
<literal>active</literal> (session logged in and
active, i.e. in the foreground),
<literal>closing</literal> (session nominally logged
out, but some processes belonging to it are still
around). In the future additional states might be
defined, client code should be written to be robust in
regards to additional state strings being
returned. This function is a more generic version of
<function>sd_session_is_active()</function>. The returned
string needs to be freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_uid()</function> may be
used to determine the user identifier of the Unix user the session
identified by the specified session identifier belongs
to.</para>
<para><function>sd_session_get_seat()</function> may
be used to determine the seat identifier of the seat
the session identified by the specified session
identifier belongs to. Note that not all sessions are
attached to a seat, this call will fail for them. The
returned string needs to be freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_service()</function>
may be used to determine the name of the service (as
passed during PAM session setup) that registered the
session identified by the specified session
identifier. The returned string needs to be freed with
the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_type()</function> may
be used to determine the type of the session
identified by the specified session identifier. The
returned string is one of <literal>x11</literal>,
<literal>tty</literal> or
<literal>unspecified</literal> and needs to be freed
with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_class()</function> may
be used to determine the class of the session
identified by the specified session identifier. The
returned string is one of <literal>user</literal>,
<literal>greeter</literal>,
<literal>lock-screen</literal>, or
<literal>background</literal> and needs to be freed
with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_display()</function>
may be used to determine the X11 display of the
session identified by the specified session
identifier. The returned string needs to be
freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_tty()</function>
may be used to determine the TTY device of the
session identified by the specified session
identifier. The returned string needs to be
freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
<para><function>sd_session_get_vt()</function>
may be used to determine the VT number of the
session identified by the specified session
identifier. This function will return an error if
the seat does not support VTs.</para>
<para>If the <varname>session</varname> parameter of
any of these functions is passed as
<constant>NULL</constant>, the operation is executed
for the session the calling process is a member of, if
there is any.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>If the test succeeds,
<function>sd_session_is_active()</function> returns a
positive integer, if it fails 0. On success
<function>sd_session_get_state()</function>,
<function>sd_session_get_uid()</function>,
<function>sd_session_get_seat()</function>,
<function>sd_session_get_service()</function>,
<function>sd_session_get_type()</function>,
<function>sd_session_get_class()</function>,
<function>sd_session_get_display()</function> and
<function>sd_session_get_tty()</function> return 0 or
a positive integer. On failure, these calls return a
negative errno-style error code.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>The <function>sd_session_is_active()</function>,
<function>sd_session_get_state()</function>,
<function>sd_session_get_uid()</function>,
<function>sd_session_get_seat()</function>,
<function>sd_session_get_service()</function>,
<function>sd_session_get_type()</function>,
<function>sd_session_get_class()</function>,
<function>sd_session_get_display()</function> and
<function>sd_session_get_tty()</function>
interfaces are available as shared library, which can
be compiled and linked to with the
<constant>libsystemd-login</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
file.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
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