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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
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6 | SPDX-License-Identifier: LGPL-2.1+ |
7 | ||
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8 | This file is part of systemd. |
9 | ||
10 | Copyright 2010 Lennart Poettering | |
11 | ||
12 | systemd is free software; you can redistribute it and/or modify it | |
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13 | under the terms of the GNU Lesser General Public License as published by |
14 | the Free Software Foundation; either version 2.1 of the License, or | |
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15 | (at your option) any later version. |
16 | ||
17 | systemd is distributed in the hope that it will be useful, but | |
18 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 20 | Lesser General Public License for more details. |
0b3b020a | 21 | |
5430f7f2 | 22 | You should have received a copy of the GNU Lesser General Public License |
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23 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
24 | --> | |
25 | ||
56ba3c78 | 26 | <refentry id="sd_seat_get_active" conditional='HAVE_PAM'> |
0b3b020a | 27 | |
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28 | <refentryinfo> |
29 | <title>sd_seat_get_active</title> | |
30 | <productname>systemd</productname> | |
31 | ||
32 | <authorgroup> | |
33 | <author> | |
34 | <contrib>Developer</contrib> | |
35 | <firstname>Lennart</firstname> | |
36 | <surname>Poettering</surname> | |
37 | <email>lennart@poettering.net</email> | |
38 | </author> | |
39 | </authorgroup> | |
40 | </refentryinfo> | |
41 | ||
42 | <refmeta> | |
43 | <refentrytitle>sd_seat_get_active</refentrytitle> | |
44 | <manvolnum>3</manvolnum> | |
45 | </refmeta> | |
46 | ||
47 | <refnamediv> | |
48 | <refname>sd_seat_get_active</refname> | |
49 | <refname>sd_seat_get_sessions</refname> | |
50 | <refname>sd_seat_can_multi_session</refname> | |
51 | <refname>sd_seat_can_tty</refname> | |
52 | <refname>sd_seat_can_graphical</refname> | |
53 | <refpurpose>Determine state of a specific seat</refpurpose> | |
54 | </refnamediv> | |
55 | ||
56 | <refsynopsisdiv> | |
57 | <funcsynopsis> | |
58 | <funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo> | |
59 | ||
60 | <funcprototype> | |
61 | <funcdef>int <function>sd_seat_get_active</function></funcdef> | |
62 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
63 | <paramdef>char **<parameter>session</parameter></paramdef> | |
64 | <paramdef>uid_t *<parameter>uid</parameter></paramdef> | |
65 | </funcprototype> | |
66 | ||
67 | <funcprototype> | |
68 | <funcdef>int <function>sd_seat_get_sessions</function></funcdef> | |
69 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
70 | <paramdef>char ***<parameter>sessions</parameter></paramdef> | |
71 | <paramdef>uid_t **<parameter>uid</parameter></paramdef> | |
72 | <paramdef>unsigned int *<parameter>n_uids</parameter></paramdef> | |
73 | </funcprototype> | |
74 | ||
75 | <funcprototype> | |
76 | <funcdef>int <function>sd_seat_can_multi_session</function></funcdef> | |
77 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
78 | </funcprototype> | |
79 | ||
80 | <funcprototype> | |
81 | <funcdef>int <function>sd_seat_can_tty</function></funcdef> | |
82 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
83 | </funcprototype> | |
84 | ||
85 | <funcprototype> | |
86 | <funcdef>int <function>sd_seat_can_graphical</function></funcdef> | |
87 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
88 | </funcprototype> | |
89 | </funcsynopsis> | |
90 | </refsynopsisdiv> | |
91 | ||
92 | <refsect1> | |
93 | <title>Description</title> | |
94 | ||
95 | <para><function>sd_seat_get_active()</function> may be used to | |
96 | determine which session is currently active on a seat, if there is | |
97 | any. Returns the session identifier and the user identifier of the | |
98 | Unix user the session is belonging to. Either the session or the | |
99 | user identifier parameter can be passed <constant>NULL</constant>, | |
100 | in case only one of the parameters shall be queried. The returned | |
101 | string needs to be freed with the libc | |
102 | <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
103 | call after use.</para> | |
104 | ||
105 | <para><function>sd_seat_get_sessions()</function> may be used to | |
106 | determine all sessions on the specified seat. Returns two arrays, | |
107 | one (<constant>NULL</constant> terminated) with the session | |
108 | identifiers of the sessions and one with the user identifiers of | |
109 | the Unix users the sessions belong to. An additional parameter may | |
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110 | be used to return the number of entries in the latter array. This |
111 | value is the same the return value, if the latter is nonnegative. | |
112 | The two arrays and the last parameter may be passed as | |
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113 | <constant>NULL</constant> in case these values need not to be |
114 | determined. The arrays and the strings referenced by them need to | |
115 | be freed with the libc | |
116 | <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
117 | call after use. Note that instead of an empty array | |
118 | <constant>NULL</constant> may be returned and should be considered | |
119 | equivalent to an empty array.</para> | |
120 | ||
121 | <para><function>sd_seat_can_multi_session()</function> may be used | |
122 | to determine whether a specific seat is capable of multi-session, | |
123 | i.e. allows multiple login sessions in parallel (with only one | |
124 | being active at a time).</para> | |
125 | ||
126 | <para><function>sd_seat_can_tty()</function> may be used to | |
127 | determine whether a specific seat provides TTY functionality, i.e. | |
128 | is useful as a text console.</para> | |
129 | ||
130 | <para><function>sd_seat_can_graphical()</function> may be used to | |
131 | determine whether a specific seat provides graphics functionality, | |
132 | i.e. is useful as a graphics display.</para> | |
133 | ||
134 | <para>If the <varname>seat</varname> parameter of any of these | |
135 | functions is passed as <constant>NULL</constant>, the operation is | |
136 | executed for the seat of the session of the calling process, if | |
137 | there is any.</para> | |
138 | </refsect1> | |
139 | ||
140 | <refsect1> | |
141 | <title>Return Value</title> | |
142 | ||
143 | <para> On success, <function>sd_seat_get_active()</function> | |
144 | returns 0 or a positive integer. On success, | |
145 | <function>sd_seat_get_sessions()</function> returns the number of | |
146 | entries in the session identifier array. If the test succeeds, | |
147 | <function>sd_seat_can_multi_session</function>, | |
148 | <function>sd_seat_can_tty</function> and | |
149 | <function>sd_seat_can_graphical</function> return a positive | |
150 | integer, if it fails 0. On failure, these calls return a negative | |
151 | errno-style error code.</para> | |
152 | </refsect1> | |
153 | ||
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154 | <refsect1> |
155 | <title>Errors</title> | |
156 | ||
157 | <para>Returned errors may indicate the following problems:</para> | |
158 | ||
159 | <variablelist> | |
160 | ||
161 | <varlistentry> | |
162 | <term><constant>-ENODATA</constant></term> | |
163 | ||
a8eaaee7 | 164 | <listitem><para>The given field is not specified for the described |
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165 | seat.</para> |
166 | </listitem> | |
167 | </varlistentry> | |
168 | ||
169 | <varlistentry> | |
170 | <term><constant>-ENXIO</constant></term> | |
171 | ||
172 | <listitem><para>The specified seat is unknown.</para> | |
173 | </listitem> | |
174 | </varlistentry> | |
175 | ||
176 | <varlistentry> | |
177 | <term><constant>-EINVAL</constant></term> | |
178 | ||
179 | <listitem><para>An input parameter was invalid (out of range, | |
7ca41557 | 180 | or NULL, where that is not accepted).</para></listitem> |
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181 | </varlistentry> |
182 | ||
183 | <varlistentry> | |
184 | <term><constant>-ENOMEM</constant></term> | |
185 | ||
186 | <listitem><para>Memory allocation failed.</para></listitem> | |
187 | </varlistentry> | |
188 | </variablelist> | |
189 | </refsect1> | |
190 | ||
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191 | <refsect1> |
192 | <title>Notes</title> | |
193 | ||
194 | <para>The <function>sd_seat_get_active()</function>, | |
195 | <function>sd_seat_get_sessions()</function>, | |
196 | <function>sd_seat_can_multi_session()</function>, | |
197 | <function>sd_seat_can_tty()</function> and | |
7f3fdb7f | 198 | <function>sd_seat_can_graphical()</function> interfaces are |
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199 | available as a shared library, which can be compiled and linked to |
200 | with the | |
201 | <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
202 | file.</para> | |
203 | </refsect1> | |
204 | ||
205 | <refsect1> | |
206 | <title>See Also</title> | |
207 | ||
208 | <para> | |
209 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
210 | <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
211 | <citerefentry><refentrytitle>sd_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
212 | </para> | |
213 | </refsect1> | |
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214 | |
215 | </refentry> |