mirror of
https://github.com/systemd/systemd.git
synced 2024-12-23 21:35:11 +03:00
177 lines
7.1 KiB
XML
177 lines
7.1 KiB
XML
<?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">
|
||
|
||
<!--
|
||
This file is part of systemd.
|
||
|
||
Copyright 2014 Lennart Poettering
|
||
|
||
systemd is free software; you can redistribute it and/or modify it
|
||
under the terms of the GNU Lesser General Public License as published by
|
||
the Free Software Foundation; either version 2.1 of the License, or
|
||
(at your option) any later version.
|
||
|
||
systemd is distributed in the hope that it will be useful, but
|
||
WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
Lesser General Public License for more details.
|
||
|
||
You should have received a copy of the GNU Lesser General Public License
|
||
along with systemd; If not, see <http://www.gnu.org/licenses/>.
|
||
-->
|
||
|
||
<refentry id="sd_bus_negotiate_fds" conditional="ENABLE_KDBUS">
|
||
|
||
<refentryinfo>
|
||
<title>sd_bus_negotiate_fds</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_bus_negotiate_fds</refentrytitle>
|
||
<manvolnum>3</manvolnum>
|
||
</refmeta>
|
||
|
||
<refnamediv>
|
||
<refname>sd_bus_negotiate_fds</refname>
|
||
<refname>sd_bus_negotiate_timestamps</refname>
|
||
<refname>sd_bus_negotiate_creds</refname>
|
||
|
||
<refpurpose>Control feature negotiation on bus connections</refpurpose>
|
||
</refnamediv>
|
||
|
||
<refsynopsisdiv>
|
||
<funcsynopsis>
|
||
<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_negotiate_fds</function></funcdef>
|
||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||
<paramdef>int <parameter>b</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_negotiate_timestamp</function></funcdef>
|
||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||
<paramdef>int <parameter>b</parameter></paramdef>
|
||
</funcprototype>
|
||
|
||
<funcprototype>
|
||
<funcdef>int <function>sd_bus_negotiate_creds</function></funcdef>
|
||
<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
|
||
<paramdef>int <parameter>b</parameter></paramdef>
|
||
</funcprototype>
|
||
</funcsynopsis>
|
||
</refsynopsisdiv>
|
||
|
||
<refsect1>
|
||
<title>Description</title>
|
||
|
||
<para><function>sd_bus_negotiate_fds()</function> controls whether
|
||
file descriptor passing shall be negotiated for the specified bus
|
||
connection. Takes a bus object and a boolean, which when true
|
||
enables file descriptor passing, and when false disables it. Note
|
||
that not all transports and servers support file descriptor
|
||
passing. To find out whether file descriptor passing is available
|
||
after negotiation use
|
||
<citerefentry><refentrytitle>sd_bus_can_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
and pass <constant>SD_BUS_TYPE_UNIX_FD</constant>. Note that file
|
||
descriptor passing is always enabled for both sending and
|
||
receiving or for neither, but never only in one direction. By
|
||
default file descriptor passing is negotiated for all
|
||
connections.</para>
|
||
|
||
<para>Note that when bus activation is used it is highly
|
||
recommended to set the <option>AcceptFileDescriptors=</option>
|
||
setting in the <filename>.busname</filename> unit file to the same
|
||
setting as negotiated by the program ultimately activated. By
|
||
default file descriptor passing is enabled for both.</para>
|
||
|
||
<para><function>sd_bus_negotiate_timestamps()</function> controls
|
||
whether implicit sender timestamps shall be attached automatically
|
||
to all incoming messages. Takes a bus object and a boolean, which
|
||
when true enables timestamping, and when false disables it. If
|
||
this is disabled,
|
||
<citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_bus_message_get_realtime_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_bus_message_get_seqno</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
fail with <constant>-ENODATA</constant> on incoming messages. Note
|
||
that not all transports support timestamping of messages. On local
|
||
transports the timestamping is applied by the kernel and cannot be
|
||
manipulated by userspace.</para>
|
||
|
||
<para><function>sd_bus_negotiate_creds()</function> controls
|
||
whether implicit sender credentials shall be attached
|
||
automatically to all incoming messages. Takes a bus object and a
|
||
bit mask value, which controls which credential parameters are
|
||
attached. If this is not used,
|
||
<citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
fails with <constant>-ENODATA</constant> on incoming
|
||
messages. Note that not all transports support attaching sender
|
||
credentials to messages, or do not support all types of sender
|
||
credential parameters. On local transports the sender credentials
|
||
are attached by the kernel and cannot be manipulated by
|
||
userspace. By default no sender credentials are attached.</para>
|
||
|
||
<para>These functions may be called only before the connection has
|
||
been started with
|
||
<citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Return Value</title>
|
||
|
||
<para>On success, these functions returns 0 or a
|
||
positive integer. On failure, they 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><varname>-EPERM</varname></term>
|
||
|
||
<listitem><para>The bus connection has already been started.</para></listitem>
|
||
</varlistentry>
|
||
</variablelist>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>Notes</title>
|
||
|
||
<para><function>sd_bus_negotiate_fs()</function> and the other
|
||
functions described here are available as a shared library, which
|
||
can be compiled and linked to with the
|
||
<constant>libsystemd</constant> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
||
file.</para>
|
||
</refsect1>
|
||
|
||
<refsect1>
|
||
<title>See Also</title>
|
||
|
||
<para>
|
||
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_bus_message_can_send</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_bus_message_get_monotonic_usec</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
|
||
<citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
||
</para>
|
||
</refsect1>
|
||
|
||
</refentry>
|