aboutsummaryrefslogtreecommitdiff
blob: f522f75d996826757d692621cd8afc2ca7a87472 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
<?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">

<!--
  SPDX-License-Identifier: LGPL-2.1+

  This file is part of systemd.

  Copyright 2010 Lennart Poettering
-->

<refentry id="sd_get_seats" conditional='HAVE_PAM'
          xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>sd_get_seats</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_get_seats</refentrytitle>
    <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>sd_get_seats</refname>
    <refname>sd_get_sessions</refname>
    <refname>sd_get_uids</refname>
    <refname>sd_get_machine_names</refname>
    <refpurpose>Determine available seats, sessions, logged in users and virtual machines/containers</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <funcsynopsis>
      <funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>

      <funcprototype>
        <funcdef>int <function>sd_get_seats</function></funcdef>
        <paramdef>char ***<parameter>seats</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_get_sessions</function></funcdef>
        <paramdef>char ***<parameter>sessions</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_get_uids</function></funcdef>
        <paramdef>uid_t **<parameter>users</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_get_machine_names</function></funcdef>
        <paramdef>char ***<parameter>machines</parameter></paramdef>
      </funcprototype>

    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><function>sd_get_seats()</function> may be used to determine
    all currently available local seats. Returns the number of seat
    identifiers and if the input pointer is non-NULL, a
    <constant>NULL</constant>-terminated array of seat identifiers
    is stored at the address.
    The returned array and all strings it references 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>Similarly, <function>sd_get_sessions()</function> may be
    used to determine all current login sessions.</para>

    <para>Similarly, <function>sd_get_uids()</function> may be used to
    determine all Unix users who currently have login sessions.</para>

    <para>Similarly, <function>sd_get_machine_names()</function> may
    be used to determine all current virtual machines and containers
    on the system.</para>

    <para>Note that the returned lists are not sorted and in an
    undefined order.</para>
  </refsect1>

  <refsect1>
    <title>Return Value</title>

    <para>On success, <function>sd_get_seats()</function>,
    <function>sd_get_sessions()</function>,
    <function>sd_get_uids()</function> and
    <function>sd_get_machine_names()</function> return the number of
    entries in the arrays. 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>-ENOMEM</constant></term>

        <listitem><para>Memory allocation failed.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <xi:include href="libsystemd-pkgconfig.xml" />

  <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>