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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 | <!-- | |
572eb058 | 6 | SPDX-License-Identifier: LGPL-2.1+ |
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7 | --> |
8 | ||
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9 | <refentry id="sd_seat_get_active" conditional='HAVE_PAM' |
10 | xmlns:xi="http://www.w3.org/2001/XInclude"> | |
0b3b020a | 11 | |
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12 | <refentryinfo> |
13 | <title>sd_seat_get_active</title> | |
14 | <productname>systemd</productname> | |
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15 | </refentryinfo> |
16 | ||
17 | <refmeta> | |
18 | <refentrytitle>sd_seat_get_active</refentrytitle> | |
19 | <manvolnum>3</manvolnum> | |
20 | </refmeta> | |
21 | ||
22 | <refnamediv> | |
23 | <refname>sd_seat_get_active</refname> | |
24 | <refname>sd_seat_get_sessions</refname> | |
25 | <refname>sd_seat_can_multi_session</refname> | |
26 | <refname>sd_seat_can_tty</refname> | |
27 | <refname>sd_seat_can_graphical</refname> | |
28 | <refpurpose>Determine state of a specific seat</refpurpose> | |
29 | </refnamediv> | |
30 | ||
31 | <refsynopsisdiv> | |
32 | <funcsynopsis> | |
33 | <funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo> | |
34 | ||
35 | <funcprototype> | |
36 | <funcdef>int <function>sd_seat_get_active</function></funcdef> | |
37 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
38 | <paramdef>char **<parameter>session</parameter></paramdef> | |
39 | <paramdef>uid_t *<parameter>uid</parameter></paramdef> | |
40 | </funcprototype> | |
41 | ||
42 | <funcprototype> | |
43 | <funcdef>int <function>sd_seat_get_sessions</function></funcdef> | |
44 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
45 | <paramdef>char ***<parameter>sessions</parameter></paramdef> | |
46 | <paramdef>uid_t **<parameter>uid</parameter></paramdef> | |
47 | <paramdef>unsigned int *<parameter>n_uids</parameter></paramdef> | |
48 | </funcprototype> | |
49 | ||
50 | <funcprototype> | |
51 | <funcdef>int <function>sd_seat_can_multi_session</function></funcdef> | |
52 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
53 | </funcprototype> | |
54 | ||
55 | <funcprototype> | |
56 | <funcdef>int <function>sd_seat_can_tty</function></funcdef> | |
57 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
58 | </funcprototype> | |
59 | ||
60 | <funcprototype> | |
61 | <funcdef>int <function>sd_seat_can_graphical</function></funcdef> | |
62 | <paramdef>const char *<parameter>seat</parameter></paramdef> | |
63 | </funcprototype> | |
64 | </funcsynopsis> | |
65 | </refsynopsisdiv> | |
66 | ||
67 | <refsect1> | |
68 | <title>Description</title> | |
69 | ||
70 | <para><function>sd_seat_get_active()</function> may be used to | |
71 | determine which session is currently active on a seat, if there is | |
72 | any. Returns the session identifier and the user identifier of the | |
73 | Unix user the session is belonging to. Either the session or the | |
74 | user identifier parameter can be passed <constant>NULL</constant>, | |
75 | in case only one of the parameters shall be queried. The returned | |
76 | string needs to be freed with the libc | |
77 | <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
78 | call after use.</para> | |
79 | ||
80 | <para><function>sd_seat_get_sessions()</function> may be used to | |
81 | determine all sessions on the specified seat. Returns two arrays, | |
82 | one (<constant>NULL</constant> terminated) with the session | |
83 | identifiers of the sessions and one with the user identifiers of | |
84 | the Unix users the sessions belong to. An additional parameter may | |
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85 | be used to return the number of entries in the latter array. This |
86 | value is the same the return value, if the latter is nonnegative. | |
87 | The two arrays and the last parameter may be passed as | |
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88 | <constant>NULL</constant> in case these values need not to be |
89 | determined. The arrays and the strings referenced by them need to | |
90 | be freed with the libc | |
91 | <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
92 | call after use. Note that instead of an empty array | |
93 | <constant>NULL</constant> may be returned and should be considered | |
94 | equivalent to an empty array.</para> | |
95 | ||
96 | <para><function>sd_seat_can_multi_session()</function> may be used | |
97 | to determine whether a specific seat is capable of multi-session, | |
98 | i.e. allows multiple login sessions in parallel (with only one | |
99 | being active at a time).</para> | |
100 | ||
101 | <para><function>sd_seat_can_tty()</function> may be used to | |
102 | determine whether a specific seat provides TTY functionality, i.e. | |
103 | is useful as a text console.</para> | |
104 | ||
105 | <para><function>sd_seat_can_graphical()</function> may be used to | |
106 | determine whether a specific seat provides graphics functionality, | |
107 | i.e. is useful as a graphics display.</para> | |
108 | ||
109 | <para>If the <varname>seat</varname> parameter of any of these | |
110 | functions is passed as <constant>NULL</constant>, the operation is | |
111 | executed for the seat of the session of the calling process, if | |
112 | there is any.</para> | |
113 | </refsect1> | |
114 | ||
115 | <refsect1> | |
116 | <title>Return Value</title> | |
117 | ||
118 | <para> On success, <function>sd_seat_get_active()</function> | |
119 | returns 0 or a positive integer. On success, | |
120 | <function>sd_seat_get_sessions()</function> returns the number of | |
121 | entries in the session identifier array. If the test succeeds, | |
122 | <function>sd_seat_can_multi_session</function>, | |
123 | <function>sd_seat_can_tty</function> and | |
124 | <function>sd_seat_can_graphical</function> return a positive | |
125 | integer, if it fails 0. On failure, these calls return a negative | |
126 | errno-style error code.</para> | |
127 | </refsect1> | |
128 | ||
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129 | <refsect1> |
130 | <title>Errors</title> | |
131 | ||
132 | <para>Returned errors may indicate the following problems:</para> | |
133 | ||
134 | <variablelist> | |
135 | ||
136 | <varlistentry> | |
137 | <term><constant>-ENODATA</constant></term> | |
138 | ||
a8eaaee7 | 139 | <listitem><para>The given field is not specified for the described |
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140 | seat.</para> |
141 | </listitem> | |
142 | </varlistentry> | |
143 | ||
144 | <varlistentry> | |
145 | <term><constant>-ENXIO</constant></term> | |
146 | ||
147 | <listitem><para>The specified seat is unknown.</para> | |
148 | </listitem> | |
149 | </varlistentry> | |
150 | ||
151 | <varlistentry> | |
152 | <term><constant>-EINVAL</constant></term> | |
153 | ||
154 | <listitem><para>An input parameter was invalid (out of range, | |
7ca41557 | 155 | or NULL, where that is not accepted).</para></listitem> |
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156 | </varlistentry> |
157 | ||
158 | <varlistentry> | |
159 | <term><constant>-ENOMEM</constant></term> | |
160 | ||
161 | <listitem><para>Memory allocation failed.</para></listitem> | |
162 | </varlistentry> | |
163 | </variablelist> | |
164 | </refsect1> | |
165 | ||
7d6b2723 | 166 | <xi:include href="libsystemd-pkgconfig.xml" /> |
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167 | |
168 | <refsect1> | |
169 | <title>See Also</title> | |
170 | ||
171 | <para> | |
172 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
173 | <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
174 | <citerefentry><refentrytitle>sd_session_get_seat</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
175 | </para> | |
176 | </refsect1> | |
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177 | |
178 | </refentry> |