216 lines
7.3 KiB
XML
216 lines
7.3 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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SPDX-License-Identifier: LGPL-2.1+
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This file is part of systemd.
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Copyright 2013 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="sd_bus_request_name">
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<refentryinfo>
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<title>sd_bus_request_name</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_bus_request_name</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_bus_request_name</refname>
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<refname>sd_bus_release_name</refname>
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<refpurpose>Request or release a well-known service name on a bus</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>int <function>sd_bus_request_name</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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<paramdef>const char *<parameter>name</parameter></paramdef>
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<paramdef>uint64_t <parameter>flags</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_bus_release_name</function></funcdef>
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<paramdef>sd_bus *<parameter>bus</parameter></paramdef>
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<paramdef>const char *<parameter>name</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_bus_request_name()</function> requests a
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well-known service name on a bus. It takes a bus connection, a
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valid bus name and a flags parameter. The flags parameter is a
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combination of the following flags:</para>
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<variablelist>
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<varlistentry>
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<term><varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname></term>
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<listitem><para>After acquiring the name successfully, permit
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other peers to take over the name when they try to acquire it
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with the <varname>SD_BUS_NAME_REPLACE_EXISTING</varname> flag
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set. If <varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname> is
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not set on the original request, such a request by other peers
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will be denied.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>SD_BUS_NAME_REPLACE_EXISTING</varname></term>
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<listitem><para>Take over the name if it is already acquired
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by another peer, and that other peer has permitted takeover by
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setting <varname>SD_BUS_NAME_ALLOW_REPLACEMENT</varname> while
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acquiring it.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>SD_BUS_NAME_QUEUE</varname></term>
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<listitem><para>Queue the acquisition of the name when the
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name is already taken.</para></listitem>
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</varlistentry>
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</variablelist>
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<para><function>sd_bus_release_name()</function> releases an
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acquired well-known name. It takes a bus connection and a valid
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bus name as parameters.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para>On success, these calls return 0 or a positive integer. On
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failure, these calls return a negative errno-style error
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code.</para>
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<para>If <varname>SD_BUS_NAME_QUEUE</varname> is specified,
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<function>sd_bus_request_name()</function> will return 0 when the
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name is already taken by another peer and the client has been
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added to the queue for the name. In that case, the caller can
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subscribe to <literal>NameOwnerChanged</literal> signals to be
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notified when the name is successfully acquired.
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<function>sd_bus_request_name()</function> returns > 0 when the
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name has immediately been acquired successfully.</para>
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</refsect1>
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<refsect1>
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<title>Errors</title>
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<para>Returned errors may indicate the following problems:</para>
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<variablelist>
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<varlistentry>
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<term><constant>-EALREADY</constant></term>
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<listitem><para>The caller already is the owner of the
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specified name.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EEXIST</constant></term>
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<listitem><para>The name has already been acquired by a
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different peer, and SD_BUS_NAME_REPLACE_EXISTING was not
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specified or the other peer did not specify
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SD_BUS_NAME_ALLOW_REPLACEMENT while acquiring the
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name.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ESRCH</constant></term>
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<listitem><para>It was attempted to release a name that is
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currently not registered on the bus.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EADDRINUSE</constant></term>
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<listitem><para>It was attempted to release a name that is
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owned by a different peer on the bus.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-EINVAL</constant></term>
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<listitem><para>A specified parameter is invalid. This is also
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generated when the requested name is a special service name
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reserved by the D-Bus specification, or when the operation is
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requested on a connection that does not refer to a
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bus.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ENOTCONN</constant></term>
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<listitem><para>The bus connection has been
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disconnected.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><constant>-ECHILD</constant></term>
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<listitem><para>The bus connection has been created in a
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different process than the current one.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>The <function>sd_bus_acquire_name()</function> and
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<function>sd_bus_release_name()</function> interfaces are
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available as a shared library, which can be compiled and linked to
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with the
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<constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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file.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd_bus_new</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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