1 <?xml version='
1.0'
?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.2//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
6 This file is part of systemd.
8 Copyright 2010 Lennart Poettering
10 systemd is free software; you can redistribute it and/or modify it
11 under the terms of the GNU Lesser General Public License as published by
12 the Free Software Foundation; either version 2.1 of the License, or
13 (at your option) any later version.
15 systemd is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
20 You should have received a copy of the GNU Lesser General Public License
21 along with systemd; If not, see <http://www.gnu.org/licenses/>.
24 <refentry id=
"sd_seat_get_active" conditional='HAVE_PAM'
>
27 <title>sd_seat_get_active
</title>
28 <productname>systemd
</productname>
32 <contrib>Developer
</contrib>
33 <firstname>Lennart
</firstname>
34 <surname>Poettering
</surname>
35 <email>lennart@poettering.net
</email>
41 <refentrytitle>sd_seat_get_active
</refentrytitle>
42 <manvolnum>3</manvolnum>
46 <refname>sd_seat_get_active
</refname>
47 <refname>sd_seat_get_sessions
</refname>
48 <refname>sd_seat_can_multi_session
</refname>
49 <refname>sd_seat_can_tty
</refname>
50 <refname>sd_seat_can_graphical
</refname>
51 <refpurpose>Determine state of a specific seat
</refpurpose>
56 <funcsynopsisinfo>#include
<systemd/sd-login.h
></funcsynopsisinfo>
59 <funcdef>int
<function>sd_seat_get_active
</function></funcdef>
60 <paramdef>const char *
<parameter>seat
</parameter></paramdef>
61 <paramdef>char **
<parameter>session
</parameter></paramdef>
62 <paramdef>uid_t *
<parameter>uid
</parameter></paramdef>
66 <funcdef>int
<function>sd_seat_get_sessions
</function></funcdef>
67 <paramdef>const char *
<parameter>seat
</parameter></paramdef>
68 <paramdef>char ***
<parameter>sessions
</parameter></paramdef>
69 <paramdef>uid_t **
<parameter>uid
</parameter></paramdef>
70 <paramdef>unsigned int *
<parameter>n_uids
</parameter></paramdef>
74 <funcdef>int
<function>sd_seat_can_multi_session
</function></funcdef>
75 <paramdef>const char *
<parameter>seat
</parameter></paramdef>
79 <funcdef>int
<function>sd_seat_can_tty
</function></funcdef>
80 <paramdef>const char *
<parameter>seat
</parameter></paramdef>
84 <funcdef>int
<function>sd_seat_can_graphical
</function></funcdef>
85 <paramdef>const char *
<parameter>seat
</parameter></paramdef>
91 <title>Description
</title>
93 <para><function>sd_seat_get_active()
</function> may be used to
94 determine which session is currently active on a seat, if there is
95 any. Returns the session identifier and the user identifier of the
96 Unix user the session is belonging to. Either the session or the
97 user identifier parameter can be passed
<constant>NULL
</constant>,
98 in case only one of the parameters shall be queried. The returned
99 string needs to be freed with the libc
100 <citerefentry project='man-pages'
><refentrytitle>free
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
101 call after use.
</para>
103 <para><function>sd_seat_get_sessions()
</function> may be used to
104 determine all sessions on the specified seat. Returns two arrays,
105 one (
<constant>NULL
</constant> terminated) with the session
106 identifiers of the sessions and one with the user identifiers of
107 the Unix users the sessions belong to. An additional parameter may
108 be used to return the number of entries in the latter array. The
109 two arrays and the latter parameter may be passed as
110 <constant>NULL
</constant> in case these values need not to be
111 determined. The arrays and the strings referenced by them need to
112 be freed with the libc
113 <citerefentry project='man-pages'
><refentrytitle>free
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
114 call after use. Note that instead of an empty array
115 <constant>NULL
</constant> may be returned and should be considered
116 equivalent to an empty array.
</para>
118 <para><function>sd_seat_can_multi_session()
</function> may be used
119 to determine whether a specific seat is capable of multi-session,
120 i.e. allows multiple login sessions in parallel (with only one
121 being active at a time).
</para>
123 <para><function>sd_seat_can_tty()
</function> may be used to
124 determine whether a specific seat provides TTY functionality, i.e.
125 is useful as a text console.
</para>
127 <para><function>sd_seat_can_graphical()
</function> may be used to
128 determine whether a specific seat provides graphics functionality,
129 i.e. is useful as a graphics display.
</para>
131 <para>If the
<varname>seat
</varname> parameter of any of these
132 functions is passed as
<constant>NULL
</constant>, the operation is
133 executed for the seat of the session of the calling process, if
138 <title>Return Value
</title>
140 <para> On success,
<function>sd_seat_get_active()
</function>
141 returns
0 or a positive integer. On success,
142 <function>sd_seat_get_sessions()
</function> returns the number of
143 entries in the session identifier array. If the test succeeds,
144 <function>sd_seat_can_multi_session
</function>,
145 <function>sd_seat_can_tty
</function> and
146 <function>sd_seat_can_graphical
</function> return a positive
147 integer, if it fails
0. On failure, these calls return a negative
148 errno-style error code.
</para>
154 <para>The
<function>sd_seat_get_active()
</function>,
155 <function>sd_seat_get_sessions()
</function>,
156 <function>sd_seat_can_multi_session()
</function>,
157 <function>sd_seat_can_tty()
</function> and
158 <function>sd_seat_can_grapical()
</function> interfaces are
159 available as a shared library, which can be compiled and linked to
161 <constant>libsystemd
</constant> <citerefentry project='die-net'
><refentrytitle>pkg-config
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
166 <title>See Also
</title>
169 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
170 <citerefentry><refentrytitle>sd-login
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
171 <citerefentry><refentrytitle>sd_session_get_seat
</refentrytitle><manvolnum>3</manvolnum></citerefentry>