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707b66c663
Makre sure we always return sensible errors for the various, following the same rules, and document them in a comment in sd-login.c. Also, update all relevant man pages accordingly.
360 lines
15 KiB
XML
360 lines
15 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="sd_session_is_active" conditional='HAVE_PAM'>
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<refentryinfo>
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<title>sd_session_is_active</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_session_is_active</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_session_is_active</refname>
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<refname>sd_session_is_remote</refname>
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<refname>sd_session_get_state</refname>
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<refname>sd_session_get_uid</refname>
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<refname>sd_session_get_seat</refname>
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<refname>sd_session_get_service</refname>
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<refname>sd_session_get_type</refname>
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<refname>sd_session_get_class</refname>
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<refname>sd_session_get_desktop</refname>
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<refname>sd_session_get_display</refname>
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<refname>sd_session_get_tty</refname>
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<refname>sd_session_get_vt</refname>
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<refname>sd_session_get_remote_host</refname>
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<refname>sd_session_get_remote_user</refname>
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<refpurpose>Determine state of a specific session</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_session_is_active</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_is_remote</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_state</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>state</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_uid</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>uid_t *<parameter>uid</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_seat</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>seat</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_service</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>service</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_type</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>type</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_class</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>class</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_desktop</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>desktop</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_display</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>display</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_remote_host</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>remote_host</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_remote_user</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>remote_user</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_tty</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>char **<parameter>tty</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_session_get_vt</function></funcdef>
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<paramdef>const char *<parameter>session</parameter></paramdef>
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<paramdef>unsigned int *<parameter>vt</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_session_is_active()</function> may be used to
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determine whether the session identified by the specified session
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identifier is currently active (i.e. currently in the foreground
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and available for user input) or not.</para>
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<para><function>sd_session_is_remote()</function> may be used to
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determine whether the session identified by the specified session
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identifier is a remote session (i.e. its remote host is known) or
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not.</para>
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<para><function>sd_session_get_state()</function> may be used to
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determine the state of the session identified by the specified
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session identifier. The following states are currently known:
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<literal>online</literal> (session logged in, but session not
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active, i.e. not in the foreground), <literal>active</literal>
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(session logged in and active, i.e. in the foreground),
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<literal>closing</literal> (session nominally logged out, but some
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processes belonging to it are still around). In the future
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additional states might be defined, client code should be written
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to be robust in regards to additional state strings being
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returned. This function is a more generic version of
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<function>sd_session_is_active()</function>. The returned string
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needs to be freed with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_uid()</function> may be used to
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determine the user identifier of the Unix user the session
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identified by the specified session identifier belongs to.</para>
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<para><function>sd_session_get_seat()</function> may be used to
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determine the seat identifier of the seat the session identified
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by the specified session identifier belongs to. Note that not all
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sessions are attached to a seat, this call will fail for them. The
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returned string needs to be freed with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_service()</function> may be used to
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determine the name of the service (as passed during PAM session
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setup) that registered the session identified by the specified
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session identifier. The returned string needs to be freed with the
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libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_type()</function> may be used to
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determine the type of the session identified by the specified
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session identifier. The returned string is one of
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<literal>x11</literal>, <literal>wayland</literal>,
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<literal>tty</literal>, <literal>mir</literal> or
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<literal>unspecified</literal> and needs to be freed with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_class()</function> may be used to
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determine the class of the session identified by the specified
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session identifier. The returned string is one of
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<literal>user</literal>, <literal>greeter</literal>,
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<literal>lock-screen</literal>, or <literal>background</literal>
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and needs to be freed with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_desktop()</function> may be used to
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determine the brand of the desktop running on the session
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identified by the specified session identifier. This field can be
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set freely by desktop environments and does not follow any special
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formatting. However, desktops are strongly recommended to use the
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same identifiers and capitalization as for
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<varname>$XDG_CURRENT_DESKTOP</varname>, as defined by the <ulink
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url="http://standards.freedesktop.org/desktop-entry-spec/latest/">Desktop
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Entry Specification</ulink>. The returned string needs to be freed
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with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_display()</function> may be used to
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determine the X11 display of the session identified by the
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specified session identifier. The returned string needs to be
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freed with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_remote_host()</function> may be
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used to determine the remote hostname of the session identified by
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the specified session identifier. The returned string needs to be
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freed with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_remote_user()</function> may be
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used to determine the remote username of the session identified by
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the specified session identifier. The returned string needs to be
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freed with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use. Note that this value is rarely known to the
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system, and even then should not be relied on.</para>
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<para><function>sd_session_get_tty()</function> may be used to
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determine the TTY device of the session identified by the
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specified session identifier. The returned string needs to be
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freed with the libc
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<citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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call after use.</para>
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<para><function>sd_session_get_vt()</function> may be used to
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determine the VT number of the session identified by the specified
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session identifier. This function will return an error if the seat
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does not support VTs.</para>
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<para>If the <varname>session</varname> parameter of any of these
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functions is passed as <constant>NULL</constant>, the operation is
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executed for the session the calling process is a member of, if
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there is any.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>If the test succeeds,
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<function>sd_session_is_active()</function> and
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<function>sd_session_is_remote()</function> return a
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positive integer; if it fails, 0. On success,
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<function>sd_session_get_state()</function>,
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<function>sd_session_get_uid()</function>,
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<function>sd_session_get_seat()</function>,
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<function>sd_session_get_service()</function>,
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<function>sd_session_get_type()</function>,
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<function>sd_session_get_class()</function>,
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<function>sd_session_get_display()</function>,
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<function>sd_session_get_remote_user()</function>,
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<function>sd_session_get_remote_host()</function> and
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<function>sd_session_get_tty()</function> return 0 or
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a positive integer. On failure, these calls return a
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negative errno-style error code.</para>
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</refsect1>
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<refsect1>
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<title>Errors</title>
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<para>Returned errors may indicate the following problems:</para>
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<variablelist>
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<varlistentry>
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<term><constant>-ENXIO</constant></term>
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<listitem><para>The specified session does not exist.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENODATA</constant></term>
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<listitem><para>Given field is not specified for the described
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session.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EINVAL</constant></term>
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<listitem><para>An input parameter was invalid (out of range,
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or NULL, where that's not accepted).</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENOMEM</constant></term>
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<listitem><para>Memory allocation failed.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>The <function>sd_session_is_active()</function>,
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<function>sd_session_get_state()</function>,
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<function>sd_session_get_uid()</function>,
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<function>sd_session_get_seat()</function>,
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<function>sd_session_get_service()</function>,
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<function>sd_session_get_type()</function>,
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<function>sd_session_get_class()</function>,
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<function>sd_session_get_display()</function>,
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<function>sd_session_get_remote_host()</function>,
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<function>sd_session_get_remote_user()</function> and
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<function>sd_session_get_tty()</function>
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interfaces are available as a shared library, which can
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be compiled and linked to with the
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<constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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file.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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