+++ /dev/null
-<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
-<!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.
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- 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>
- <paramdef>uint64_t <parameter>flags</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. It 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_seqnum</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. By default, message timestamping is
- not negotiated for all connections.</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, a
- boolean indicating whether to enable or disable the credential
- parts encoded in the bit mask value argument. Note that not all
- transports support attaching sender credentials to messages, or do
- not support all types of sender credential parameters, or might
- suppress them under certain circumstances for individual
- messages. 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>The <function>sd_bus_negotiate_fds()</function> function may
- be called only before the connection has been started with
- <citerefentry><refentrytitle>sd_bus_start</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Both
- <function>sd_bus_negotiate_timestamp()</function> and
- <function>sd_bus_negotiate_creds()</function> also may be called
- after a connection has been set up. Note that when operating on a
- connection that is shared between multiple components of the same
- program (for example via
- <citerefentry><refentrytitle>sd_bus_default</refentrytitle><manvolnum>3</manvolnum></citerefentry>)
- it is highly recommended to only enable additional per message
- metadata fields, but never disable them again, in order not to
- disable functionality needed by other components.</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><constant>-EPERM</constant></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 project='die-net'><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>,
- <citerefentry><refentrytitle>systemd.busname</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- </para>
- </refsect1>
-
-</refentry>
~ianmdlvl / elogind.git / blobdiff