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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. |
01448ff9 | 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 | ||
56ba3c78 | 24 | <refentry id="sd-login" conditional='HAVE_PAM'> |
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25 | |
26 | <refentryinfo> | |
27 | <title>sd-login</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</refentrytitle> | |
cb07866b | 42 | <manvolnum>3</manvolnum> |
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43 | </refmeta> |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd-login</refname> | |
47 | <refpurpose>APIs for | |
48 | tracking logins</refpurpose> | |
49 | </refnamediv> | |
50 | ||
51 | <refsynopsisdiv> | |
52 | <funcsynopsis> | |
53 | <funcsynopsisinfo>#include <systemd/sd-login.h></funcsynopsisinfo> | |
54 | </funcsynopsis> | |
55 | ||
56 | <cmdsynopsis> | |
57 | <command>pkg-config --cflags --libs libsystemd-login</command> | |
58 | </cmdsynopsis> | |
59 | </refsynopsisdiv> | |
60 | ||
61 | <refsect1> | |
62 | <title>Description</title> | |
63 | ||
64 | <para><filename>sd-login.h</filename> provides APIs to | |
65 | introspect and monitor seat, login session and user | |
66 | status information on the local system. </para> | |
67 | ||
68 | <para>See <ulink | |
69 | url="http://www.freedesktop.org/wiki/Software/systemd/multiseat">Multi-Seat | |
70 | on Linux</ulink> for an introduction into multi-seat | |
71 | support on Linux, the background for this set of APIs.</para> | |
72 | ||
73 | <para>Note that these APIs only allow purely passive access | |
74 | and monitoring of seats, sessions and users. To | |
75 | actively make changes to the seat configuration, | |
76 | terminate login sessions, or switch session on a seat | |
77 | you need to utilize the D-Bus API of | |
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78 | systemd-logind, instead.</para> |
79 | ||
5079a105 | 80 | <para>These functions synchronously access data in |
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81 | <filename>/proc</filename>, |
82 | <filename>/sys/fs/cgroup</filename> and | |
83 | <filename>/run</filename>. All of these are virtual | |
84 | file systems, hence the runtime cost of the accesses | |
85 | is relatively cheap.</para> | |
86 | ||
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87 | <para>It is possible (and often a very good choice) to |
88 | mix calls to the synchronous interface of | |
89 | <filename>sd-login.h</filename> with the asynchronous | |
90 | D-Bus interface of systemd-logind. However, if this is | |
91 | done you need to think a bit about possible races | |
92 | since the stream of events from D-Bus and from | |
93 | <filename>sd-login.h</filename> interfaces such as the | |
94 | login monitor are asynchronous and not ordered against | |
95 | each other.</para> | |
96 | ||
595aae37 | 97 | <para>If the functions return string arrays, these are |
74d00578 | 98 | generally <constant>NULL</constant> terminated and need to be freed by the |
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99 | caller with the libc |
100 | <citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
101 | call after use, including the strings referenced | |
494a6682 | 102 | therein. Similarly, individual strings returned need to |
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103 | be freed, as well.</para> |
104 | ||
105 | <para>As a special exception, instead of an empty | |
74d00578 | 106 | string array <constant>NULL</constant> may be returned, which should be |
595aae37 | 107 | treated equivalent to an empty string array.</para> |
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108 | |
109 | <para>See | |
110 | <citerefentry><refentrytitle>sd_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
111 | <citerefentry><refentrytitle>sd_uid_get_state</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
112 | <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
113 | <citerefentry><refentrytitle>sd_seat_get_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
114 | <citerefentry><refentrytitle>sd_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
115 | <citerefentry><refentrytitle>sd_login_monitor_new</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
116 | for more information about the functions | |
117 | implemented.</para> | |
118 | </refsect1> | |
119 | ||
120 | <refsect1> | |
121 | <title>Notes</title> | |
122 | ||
494a6682 | 123 | <para>These APIs are implemented as a shared library, |
01448ff9 | 124 | which can be compiled and linked to with the |
1e158d27 | 125 | <constant>libsystemd-login</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
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126 | file.</para> |
127 | </refsect1> | |
128 | ||
129 | <refsect1> | |
130 | <title>See Also</title> | |
131 | <para> | |
132 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
133 | <citerefentry><refentrytitle>sd_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
134 | <citerefentry><refentrytitle>sd_uid_get_state</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
135 | <citerefentry><refentrytitle>sd_session_is_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
136 | <citerefentry><refentrytitle>sd_seat_get_active</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
137 | <citerefentry><refentrytitle>sd_get_seats</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
138 | <citerefentry><refentrytitle>sd_login_monitor_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
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139 | <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
140 | <citerefentry><refentrytitle>sd-readahead</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
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141 | <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
142 | </para> | |
143 | </refsect1> | |
144 | ||
145 | </refentry> |