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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 2014 Lennart Poettering | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
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 | |
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 | |
18 | Lesser General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU Lesser General Public License | |
21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
22 | --> | |
23 | ||
24 | <refentry id="sd_bus_negotiate_fds" conditional="ENABLE_KDBUS"> | |
25 | ||
26 | <refentryinfo> | |
faae655d | 27 | <title>sd_bus_negotiate_fds</title> |
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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_bus_negotiate_fds</refentrytitle> | |
42 | <manvolnum>3</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd_bus_negotiate_fds</refname> | |
47 | <refname>sd_bus_negotiate_timestamps</refname> | |
48 | <refname>sd_bus_negotiate_creds</refname> | |
49 | ||
50 | <refpurpose>Control feature negotiation on bus connections</refpurpose> | |
51 | </refnamediv> | |
52 | ||
53 | <refsynopsisdiv> | |
54 | <funcsynopsis> | |
55 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
56 | ||
57 | <funcprototype> | |
58 | <funcdef>int <function>sd_bus_negotiate_fds</function></funcdef> | |
59 | <paramdef>sd_bus *<parameter>bus</parameter></paramdef> | |
60 | <paramdef>int <parameter>b</parameter></paramdef> | |
61 | </funcprototype> | |
62 | ||
63 | <funcprototype> | |
64 | <funcdef>int <function>sd_bus_negotiate_timestamp</function></funcdef> | |
65 | <paramdef>sd_bus *<parameter>bus</parameter></paramdef> | |
66 | <paramdef>int <parameter>b</parameter></paramdef> | |
67 | </funcprototype> | |
68 | ||
69 | <funcprototype> | |
70 | <funcdef>int <function>sd_bus_negotiate_creds</function></funcdef> | |
71 | <paramdef>sd_bus *<parameter>bus</parameter></paramdef> | |
72 | <paramdef>int <parameter>b</parameter></paramdef> | |
73 | </funcprototype> | |
74 | </funcsynopsis> | |
75 | </refsynopsisdiv> | |
76 | ||
77 | <refsect1> | |
78 | <title>Description</title> | |
79 | ||
80 | <para><function>sd_bus_negotiate_fds()</function> controls whether | |
81 | file descriptor passing shall be negotiated for the specified bus | |
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82 | connection. It takes a bus object and a boolean, which, when true, |
83 | enables file descriptor passing, and, when false, disables it. Note | |
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84 | that not all transports and servers support file descriptor |
85 | passing. To find out whether file descriptor passing is available | |
b8bde116 | 86 | after negotiation, use |
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87 | <citerefentry><refentrytitle>sd_bus_can_send</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
88 | and pass <constant>SD_BUS_TYPE_UNIX_FD</constant>. Note that file | |
89 | descriptor passing is always enabled for both sending and | |
90 | receiving or for neither, but never only in one direction. By | |
b8bde116 | 91 | default, file descriptor passing is negotiated for all |
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92 | connections.</para> |
93 | ||
b8bde116 | 94 | <para>Note that when bus activation is used, it is highly |
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95 | recommended to set the <option>AcceptFileDescriptors=</option> |
96 | setting in the <filename>.busname</filename> unit file to the same | |
97 | setting as negotiated by the program ultimately activated. By | |
b8bde116 | 98 | default, file descriptor passing is enabled for both.</para> |
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99 | |
100 | <para><function>sd_bus_negotiate_timestamps()</function> controls | |
101 | whether implicit sender timestamps shall be attached automatically | |
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102 | to all incoming messages. Takes a bus object and a boolean, which, |
103 | when true, enables timestamping, and, when false, disables it. If | |
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104 | this is disabled, |
105 | <citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
106 | <citerefentry><refentrytitle>sd_bus_message_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
107 | <citerefentry><refentrytitle>sd_bus_message_get_seqno</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
108 | fail with <constant>-ENODATA</constant> on incoming messages. Note | |
109 | that not all transports support timestamping of messages. On local | |
b8bde116 | 110 | transports, the timestamping is applied by the kernel and cannot be |
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111 | manipulated by userspace.</para> |
112 | ||
113 | <para><function>sd_bus_negotiate_creds()</function> controls | |
114 | whether implicit sender credentials shall be attached | |
115 | automatically to all incoming messages. Takes a bus object and a | |
116 | bit mask value, which controls which credential parameters are | |
117 | attached. If this is not used, | |
118 | <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
119 | fails with <constant>-ENODATA</constant> on incoming | |
120 | messages. Note that not all transports support attaching sender | |
121 | credentials to messages, or do not support all types of sender | |
b8bde116 | 122 | credential parameters. On local transports, the sender credentials |
ce236b57 | 123 | are attached by the kernel and cannot be manipulated by |
b8bde116 | 124 | userspace. By default, no sender credentials are attached.</para> |
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125 | |
126 | <para>These functions may be called only before the connection has | |
127 | been started with | |
128 | <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> | |
129 | </refsect1> | |
130 | ||
131 | <refsect1> | |
132 | <title>Return Value</title> | |
133 | ||
134 | <para>On success, these functions returns 0 or a | |
faae655d | 135 | positive integer. On failure, they return a negative errno-style |
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136 | error code.</para> |
137 | </refsect1> | |
138 | ||
139 | <refsect1> | |
140 | <title>Errors</title> | |
141 | ||
142 | <para>Returned errors may indicate the following problems:</para> | |
143 | ||
144 | <variablelist> | |
145 | <varlistentry> | |
8474b70c | 146 | <term><constant>-EPERM</constant></term> |
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147 | |
148 | <listitem><para>The bus connection has already been started.</para></listitem> | |
149 | </varlistentry> | |
150 | </variablelist> | |
151 | </refsect1> | |
152 | ||
153 | <refsect1> | |
154 | <title>Notes</title> | |
155 | ||
156 | <para><function>sd_bus_negotiate_fs()</function> and the other | |
157 | functions described here are available as a shared library, which | |
158 | can be compiled and linked to with the | |
5aded369 | 159 | <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
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160 | file.</para> |
161 | </refsect1> | |
162 | ||
163 | <refsect1> | |
164 | <title>See Also</title> | |
165 | ||
166 | <para> | |
167 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
168 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
169 | <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
170 | <citerefentry><refentrytitle>sd_bus_message_can_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
171 | <citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
172 | <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
173 | </para> | |
174 | </refsect1> | |
175 | ||
176 | </refentry> |