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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"> | |
4 | ||
5 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2010 Lennart Poettering | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
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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 | |
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13 | (at your option) any later version. |
14 | ||
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 | |
5430f7f2 | 18 | Lesser General Public License for more details. |
0b3b020a | 19 | |
5430f7f2 | 20 | You should have received a copy of the GNU Lesser General Public License |
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21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
22 | --> | |
23 | ||
24 | <refentry id="sd_login_monitor_new"> | |
25 | ||
26 | <refentryinfo> | |
27 | <title>sd_login_monitor_new</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <contrib>Developer</contrib> | |
33 | <firstname>Lennart</firstname> | |
34 | <surname>Poettering</surname> | |
35 | <email>lennart@poettering.net</email> | |
36 | </author> | |
37 | </authorgroup> | |
38 | </refentryinfo> | |
39 | ||
40 | <refmeta> | |
41 | <refentrytitle>sd_login_monitor_new</refentrytitle> | |
42 | <manvolnum>3</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd_login_monitor_new</refname> | |
47 | <refname>sd_login_monitor_unref</refname> | |
48 | <refname>sd_login_monitor_flush</refname> | |
49 | <refname>sd_login_monitor_get_fd</refname> | |
50 | <refpurpose>Monitor login sessions, seats and users</refpurpose> | |
51 | </refnamediv> | |
52 | ||
53 | <refsynopsisdiv> | |
54 | <funcsynopsis> | |
55 | <funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo> | |
56 | ||
57 | <funcprototype> | |
58 | <funcdef>int <function>sd_login_monitor_new</function></funcdef> | |
59 | <paramdef>const char* <parameter>category</parameter></paramdef> | |
60 | <paramdef>sd_login_monitor** <parameter>ret</parameter></paramdef> | |
61 | </funcprototype> | |
62 | ||
63 | <funcprototype> | |
64 | <funcdef>sd_login_monitor* <function>sd_login_monitor_unref</function></funcdef> | |
65 | <paramdef>sd_login_monitor* <parameter>m</parameter></paramdef> | |
66 | </funcprototype> | |
67 | ||
68 | <funcprototype> | |
69 | <funcdef>int <function>sd_login_monitor_flush</function></funcdef> | |
70 | <paramdef>sd_login_monitor* <parameter>m</parameter></paramdef> | |
71 | </funcprototype> | |
72 | ||
73 | <funcprototype> | |
74 | <funcdef>int <function>sd_login_monitor_get_fd</function></funcdef> | |
75 | <paramdef>sd_login_monitor* <parameter>m</parameter></paramdef> | |
76 | </funcprototype> | |
77 | ||
78 | </funcsynopsis> | |
79 | </refsynopsisdiv> | |
80 | ||
81 | <refsect1> | |
82 | <title>Description</title> | |
83 | ||
84 | <para><function>sd_login_monitor_new()</function> may | |
85 | be used to monitor login session, users and seats. Via | |
86 | a monitor object a file descriptor can be integrated | |
87 | into an application defined event loop which is woken | |
88 | up each time a user logs in, logs out or a seat is | |
89 | added or removed, or a session, user, or seat changes | |
90 | state otherwise. The first parameter takes a string | |
91 | which can be either <literal>seat</literal> (to get | |
92 | only notifications about seats being added, removed or | |
93 | changed), <literal>session</literal> (to get only | |
94 | notifications about sessions being created or removed | |
95 | or changed) or <literal>uid</literal> (to get only | |
96 | notifications when a user changes state in respect to | |
97 | logins). If notifications shall be generated in all | |
98 | these conditions, NULL may be passed. Note that in | |
99 | future additional categories may be defined. The | |
100 | second parameter returns a monitor object and needs to | |
101 | be freed with the | |
102 | <function>sd_login_monitor_unref()</function> call | |
103 | after use.</para> | |
104 | ||
105 | <para><function>sd_login_monitor_unref()</function> | |
106 | may be used to destroy a monitor object. Note that | |
107 | this will invalidate any file descriptor returned by | |
108 | <function>sd_login_monitor_get_fd()</function>.</para> | |
109 | ||
110 | <para><function>sd_login_monitor_flush()</function> | |
111 | may be used to reset the wakeup state of the monitor | |
112 | object. Whenever an event causes the monitor to wake | |
113 | up the event loop via the file descriptor this | |
114 | function needs to be called to reset the wake-up | |
115 | state. If this call is not invoked the file descriptor | |
116 | will immediately wake up the event loop again.</para> | |
117 | ||
118 | <para><function>sd_login_monitor_get_fd()</function> | |
119 | may be used to retrieve the file descriptor of the | |
120 | monitor object that may be integrated in an | |
121 | application defined event loop, based around | |
122 | <citerefentry><refentrytitle>poll</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
123 | or a similar interface. The application should include | |
124 | the returned file descriptor as wake up source for | |
125 | POLLIN events. Whenever a wake-up is triggered the | |
126 | file descriptor needs to be reset via | |
127 | <function>sd_login_monitor_flush()</function>. An | |
128 | application needs to reread the login state with a | |
129 | function like | |
130 | <citerefentry><refentrytitle>sd_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
131 | or similar to determine what changed.</para> | |
132 | </refsect1> | |
133 | ||
134 | <refsect1> | |
135 | <title>Return Value</title> | |
136 | ||
137 | <para>On success | |
138 | <function>sd_login_monitor_new()</function> and | |
139 | <function>sd_login_monitor_flush()</function> return 0 | |
140 | or a positive integer. On success | |
141 | <function>sd_login_monitor_get_fd()</function> returns | |
142 | a Unix file descriptor. On failure, these calls return | |
143 | a negative errno-style error code.</para> | |
144 | ||
145 | <para><function>sd_login_monitor_unref()</function> | |
146 | always returns NULL.</para> | |
147 | </refsect1> | |
148 | ||
149 | <refsect1> | |
150 | <title>Notes</title> | |
151 | ||
152 | <para>The <function>sd_login_monitor_new()</function>, | |
153 | <function>sd_login_monitor_unref()</function>, <function>sd_login_monitor_flush()</function> and | |
154 | <function>sd_login_monitor_get_fd()</function> interfaces | |
155 | are available as shared library, which can be compiled | |
156 | and linked to with the | |
157 | <literal>libsystemd-login</literal> | |
158 | <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> | |
159 | file.</para> | |
160 | </refsect1> | |
161 | ||
162 | <refsect1> | |
163 | <title>See Also</title> | |
164 | ||
165 | <para> | |
166 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
167 | <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>7</manvolnum></citerefentry>, | |
595aae37 | 168 | <citerefentry><refentrytitle>sd_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
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169 | </para> |
170 | </refsect1> | |
171 | ||
172 | </refentry> |