| <?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"> |
| |
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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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| |
| <refentry id="sd_seat_get_active" conditional='HAVE_PAM'> |
| |
| <refentryinfo> |
| <title>sd_seat_get_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_seat_get_active</refentrytitle> |
| <manvolnum>3</manvolnum> |
| </refmeta> |
| |
| <refnamediv> |
| <refname>sd_seat_get_active</refname> |
| <refname>sd_seat_get_sessions</refname> |
| <refname>sd_seat_can_multi_session</refname> |
| <refname>sd_seat_can_tty</refname> |
| <refname>sd_seat_can_graphical</refname> |
| <refpurpose>Determine state of a specific seat</refpurpose> |
| </refnamediv> |
| |
| <refsynopsisdiv> |
| <funcsynopsis> |
| <funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_seat_get_active</function></funcdef> |
| <paramdef>const char *<parameter>seat</parameter></paramdef> |
| <paramdef>char **<parameter>session</parameter></paramdef> |
| <paramdef>uid_t *<parameter>uid</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_seat_get_sessions</function></funcdef> |
| <paramdef>const char *<parameter>seat</parameter></paramdef> |
| <paramdef>char ***<parameter>sessions</parameter></paramdef> |
| <paramdef>uid_t **<parameter>uid</parameter></paramdef> |
| <paramdef>unsigned int *<parameter>n_uids</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_seat_can_multi_session</function></funcdef> |
| <paramdef>const char *<parameter>seat</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_seat_can_tty</function></funcdef> |
| <paramdef>const char *<parameter>seat</parameter></paramdef> |
| </funcprototype> |
| |
| <funcprototype> |
| <funcdef>int <function>sd_seat_can_graphical</function></funcdef> |
| <paramdef>const char *<parameter>seat</parameter></paramdef> |
| </funcprototype> |
| </funcsynopsis> |
| </refsynopsisdiv> |
| |
| <refsect1> |
| <title>Description</title> |
| |
| <para><function>sd_seat_get_active()</function> may be used to |
| determine which session is currently active on a seat, if there is |
| any. Returns the session identifier and the user identifier of the |
| Unix user the session is belonging to. Either the session or the |
| user identifier parameter can be passed <constant>NULL</constant>, |
| in case only one of the parameters shall be queried. The returned |
| string needs to be freed with the libc |
| <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| call after use.</para> |
| |
| <para><function>sd_seat_get_sessions()</function> may be used to |
| determine all sessions on the specified seat. Returns two arrays, |
| one (<constant>NULL</constant> terminated) with the session |
| identifiers of the sessions and one with the user identifiers of |
| the Unix users the sessions belong to. An additional parameter may |
| be used to return the number of entries in the latter array. The |
| two arrays and the latter parameter may be passed as |
| <constant>NULL</constant> in case these values need not to be |
| determined. The arrays and the strings referenced by them need to |
| be freed with the libc |
| <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| call after use. Note that instead of an empty array |
| <constant>NULL</constant> may be returned and should be considered |
| equivalent to an empty array.</para> |
| |
| <para><function>sd_seat_can_multi_session()</function> may be used |
| to determine whether a specific seat is capable of multi-session, |
| i.e. allows multiple login sessions in parallel (with only one |
| being active at a time).</para> |
| |
| <para><function>sd_seat_can_tty()</function> may be used to |
| determine whether a specific seat provides TTY functionality, i.e. |
| is useful as a text console.</para> |
| |
| <para><function>sd_seat_can_graphical()</function> may be used to |
| determine whether a specific seat provides graphics functionality, |
| i.e. is useful as a graphics display.</para> |
| |
| <para>If the <varname>seat</varname> parameter of any of these |
| functions is passed as <constant>NULL</constant>, the operation is |
| executed for the seat of the session of the calling process, if |
| there is any.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Return Value</title> |
| |
| <para> On success, <function>sd_seat_get_active()</function> |
| returns 0 or a positive integer. On success, |
| <function>sd_seat_get_sessions()</function> returns the number of |
| entries in the session identifier array. If the test succeeds, |
| <function>sd_seat_can_multi_session</function>, |
| <function>sd_seat_can_tty</function> and |
| <function>sd_seat_can_graphical</function> return a positive |
| integer, if it fails 0. On failure, these calls return a negative |
| errno-style error code.</para> |
| </refsect1> |
| |
| <refsect1> |
| <title>Errors</title> |
| |
| <para>Returned errors may indicate the following problems:</para> |
| |
| <variablelist> |
| |
| <varlistentry> |
| <term><constant>-ENODATA</constant></term> |
| |
| <listitem><para>The given field is not specified for the described |
| seat.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>-ENXIO</constant></term> |
| |
| <listitem><para>The specified seat is unknown.</para> |
| </listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>-EINVAL</constant></term> |
| |
| <listitem><para>An input parameter was invalid (out of range, |
| or NULL, where that is not accepted).</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><constant>-ENOMEM</constant></term> |
| |
| <listitem><para>Memory allocation failed.</para></listitem> |
| </varlistentry> |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>Notes</title> |
| |
| <para>The <function>sd_seat_get_active()</function>, |
| <function>sd_seat_get_sessions()</function>, |
| <function>sd_seat_can_multi_session()</function>, |
| <function>sd_seat_can_tty()</function> and |
| <function>sd_seat_can_graphical()</function> interfaces are |
| available as a shared library, which can be compiled and linked to |
| with the |
| <constant>libsystemd</constant> <citerefentry project='die-net'><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_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |