mirror of
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5aded36978
It is annoying when we have dead links on fd.o. Add project='man-pages|die-net|archlinux' to <citerefentry>-ies. In generated html, add external links to http://man7.org/linux/man-pages/man, http://linux.die.net/man/, https://www.archlinux.org/. By default, pages in sections 2 and 4 go to man7, since Michael Kerrisk is the autorative source on kernel related stuff. The rest of links goes to linux.die.net, because they have the manpages. Except for the pacman stuff, since it seems to be only available from archlinux.org. Poor gummiboot gets no link, because gummitboot(8) ain't to be found on the net. According to common wisdom, that would mean that it does not exist. But I have seen Kay using it, so I know it does, and deserves to be found. Can somebody be nice and put it up somewhere?
821 lines
48 KiB
XML
821 lines
48 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
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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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This file is part of systemd.
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Copyright 2010 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="systemd.socket">
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<refentryinfo>
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<title>systemd.socket</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>systemd.socket</refentrytitle>
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<manvolnum>5</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>systemd.socket</refname>
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<refpurpose>Socket unit configuration</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<para><filename><replaceable>socket</replaceable>.socket</filename></para>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para>A unit configuration file whose name ends in
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<literal>.socket</literal> encodes information about
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an IPC or network socket or a file system FIFO
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controlled and supervised by systemd, for socket-based
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activation.</para>
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<para>This man page lists the configuration options
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specific to this unit type. See
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<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for the common options of all unit configuration
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files. The common configuration items are configured
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in the generic [Unit] and [Install] sections. The
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socket specific configuration options are configured
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in the [Socket] section.</para>
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<para>Additional options are listed in
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<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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which define the execution environment the
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<option>ExecStartPre=</option>,
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<option>ExecStartPost=</option>,
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<option>ExecStopPre=</option> and
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<option>ExecStopPost=</option> commands are executed
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in, and in
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<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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which define the way the processes are terminated, and
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in
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<citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
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which configure resource control settings for the
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processes of the socket.</para>
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<para>For each socket file, a matching service file
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must exist, describing the service to start on
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incoming traffic on the socket (see
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<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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for more information about .service files). The name
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of the .service unit is by default the same as the
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name of the .socket unit, but can be altered with the
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<option>Service=</option> option described below.
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Depending on the setting of the <option>Accept=</option>
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option described below, this .service unit must either
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be named like the .socket unit, but with the suffix
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replaced, unless overridden with
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<option>Service=</option>; or it must be a template
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unit named the same way. Example: a socket file
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<filename>foo.socket</filename> needs a matching
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service <filename>foo.service</filename> if
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<option>Accept=false</option> is set. If
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<option>Accept=true</option> is set, a service
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template file <filename>foo@.service</filename> must
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exist from which services are instantiated for each
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incoming connection.</para>
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<para>Unless <varname>DefaultDependencies=</varname>
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is set to <option>false</option>, socket units will
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implicitly have dependencies of type
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<varname>Requires=</varname> and
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<varname>After=</varname> on
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<filename>sysinit.target</filename> as well as
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dependencies of type <varname>Conflicts=</varname> and
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<varname>Before=</varname> on
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<filename>shutdown.target</filename>. These ensure
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that socket units pull in basic system
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initialization, and are terminated cleanly prior to
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system shutdown. Only sockets involved with early
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boot or late system shutdown should disable this
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option.</para>
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<para>Socket units will have a
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<varname>Before=</varname> dependency on the service
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which they trigger added implicitly. No implicit
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<varname>WantedBy=</varname> or
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<varname>RequiredBy=</varname> dependency from the
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socket to the service is added. This means that the
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service may be started without the socket, in which
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case it must be able to open sockets by itself. To
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prevent this, an explicit <varname>Requires=</varname>
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dependency may be added.</para>
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<para>Socket units may be used to implement on-demand
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starting of services, as well as parallelized starting
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of services. See the blog stories linked at the end
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for an introduction.</para>
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<para>Note that the daemon software configured for
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socket activation with socket units needs to be able
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to accept sockets from systemd, either via systemd's
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native socket passing interface (see
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<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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for details) or via the traditional
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<citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>-style
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socket passing (i.e. sockets passed in via standard input and
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output, using <varname>StandardInput=socket</varname>
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in the service file).</para>
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</refsect1>
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<refsect1>
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<title>Options</title>
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<para>Socket files must include a [Socket] section,
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which carries information about the socket or FIFO it
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supervises. A number of options that may be used in
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this section are shared with other unit types. These
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options are documented in
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<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
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and
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<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
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options specific to the [Socket] section of socket
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units are the following:</para>
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<variablelist class='unit-directives'>
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<varlistentry>
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<term><varname>ListenStream=</varname></term>
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<term><varname>ListenDatagram=</varname></term>
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<term><varname>ListenSequentialPacket=</varname></term>
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<listitem><para>Specifies an address
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to listen on for a stream
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(<constant>SOCK_STREAM</constant>), datagram (<constant>SOCK_DGRAM</constant>),
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or sequential packet
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(<constant>SOCK_SEQPACKET</constant>) socket, respectively. The address
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can be written in various formats:</para>
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<para>If the address starts with a
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slash (<literal>/</literal>), it is read as file system
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socket in the <constant>AF_UNIX</constant> socket
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family.</para>
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<para>If the address starts with an at
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symbol (<literal>@</literal>), it is read as abstract
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namespace socket in the
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<constant>AF_UNIX</constant>
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family. The <literal>@</literal> is
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replaced with a
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<constant>NUL</constant> character
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before binding. For details, see
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<citerefentry project='man-pages'><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
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<para>If the address string is a
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single number, it is read as port
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number to listen on via
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IPv6. Depending on the value of
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<varname>BindIPv6Only=</varname> (see below) this
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might result in the service being
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available via both IPv6 and IPv4 (default) or
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just via IPv6.
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</para>
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<para>If the address string is a
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string in the format v.w.x.y:z, it is
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read as IPv4 specifier for listening
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on an address v.w.x.y on a port
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z.</para>
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<para>If the address string is a
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string in the format [x]:y, it is read
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as IPv6 address x on a port y. Note
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that this might make the service
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available via IPv4, too, depending on
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the <varname>BindIPv6Only=</varname>
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setting (see below).
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</para>
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<para>Note that <constant>SOCK_SEQPACKET</constant>
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(i.e. <varname>ListenSequentialPacket=</varname>)
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is only available for <constant>AF_UNIX</constant>
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sockets. <constant>SOCK_STREAM</constant>
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(i.e. <varname>ListenStream=</varname>)
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when used for IP sockets refers to TCP
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sockets, <constant>SOCK_DGRAM</constant>
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(i.e. <varname>ListenDatagram=</varname>)
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to UDP.</para>
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<para>These options may be specified
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more than once in which case incoming
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traffic on any of the sockets will
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trigger service activation, and all
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listed sockets will be passed to the
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service, regardless of whether there is
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incoming traffic on them or not. If
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the empty string is assigned to any of
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these options, the list of addresses
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to listen on is reset, all prior uses
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of any of these options will have no
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effect.</para>
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<para>It is also possible to have more
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than one socket unit for the same
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service when using
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<varname>Service=</varname>, and the
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service will receive all the sockets
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configured in all the socket units.
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Sockets configured in one unit are
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|
passed in the order of configuration,
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|
but no ordering between socket units
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is specified.</para>
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<para>If an IP address is used here,
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it is often desirable to listen on it
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before the interface it is configured
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on is up and running, and even
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regardless of whether it will be up and
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running at any point. To deal with this,
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it is recommended to set the
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<varname>FreeBind=</varname> option
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described below.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><varname>ListenFIFO=</varname></term>
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<listitem><para>Specifies a file
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system FIFO to listen on. This expects
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an absolute file system path as
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argument. Behavior otherwise is very
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similar to the
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<varname>ListenDatagram=</varname>
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directive above.</para></listitem>
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</varlistentry>
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<varlistentry>
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|
<term><varname>ListenSpecial=</varname></term>
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|
<listitem><para>Specifies a special
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file in the file system to listen
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on. This expects an absolute file
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system path as argument. Behavior
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otherwise is very similar to the
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<varname>ListenFIFO=</varname>
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|
directive above. Use this to open
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character device nodes as well as
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|
special files in
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|
<filename>/proc</filename> and
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|
<filename>/sys</filename>.</para></listitem>
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|
</varlistentry>
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|
<varlistentry>
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|
<term><varname>ListenNetlink=</varname></term>
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<listitem><para>Specifies a Netlink
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family to create a socket for to
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listen on. This expects a short string
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|
referring to the <constant>AF_NETLINK</constant> family
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|
name (such as <varname>audit</varname>
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|
or <varname>kobject-uevent</varname>)
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|
as argument, optionally suffixed by a
|
|
whitespace followed by a multicast
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|
group integer. Behavior otherwise is
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|
very similar to the
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<varname>ListenDatagram=</varname>
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directive above.</para></listitem>
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</varlistentry>
|
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|
|
<varlistentry>
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|
<term><varname>ListenMessageQueue=</varname></term>
|
|
<listitem><para>Specifies a POSIX
|
|
message queue name to listen on. This
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|
expects a valid message queue name
|
|
(i.e. beginning with /). Behavior
|
|
otherwise is very similar to the
|
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<varname>ListenFIFO=</varname>
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directive above. On Linux message
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queue descriptors are actually file
|
|
descriptors and can be inherited
|
|
between processes.</para></listitem>
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|
</varlistentry>
|
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|
|
<varlistentry>
|
|
<term><varname>BindIPv6Only=</varname></term>
|
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<listitem><para>Takes a one of
|
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<option>default</option>,
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<option>both</option> or
|
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<option>ipv6-only</option>. Controls
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the IPV6_V6ONLY socket option (see
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<citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for details). If
|
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<option>both</option>, IPv6 sockets
|
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bound will be accessible via both IPv4
|
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and IPv6. If
|
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<option>ipv6-only</option>, they will
|
|
be accessible via IPv6 only. If
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<option>default</option> (which is the
|
|
default, surprise!), the system wide
|
|
default setting is used, as controlled
|
|
by
|
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<filename>/proc/sys/net/ipv6/bindv6only</filename>,
|
|
which in turn defaults to the
|
|
equivalent of
|
|
<option>both</option>.</para>
|
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</listitem>
|
|
</varlistentry>
|
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|
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<varlistentry>
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|
<term><varname>Backlog=</varname></term>
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<listitem><para>Takes an unsigned
|
|
integer argument. Specifies the number
|
|
of connections to queue that have not
|
|
been accepted yet. This setting
|
|
matters only for stream and sequential
|
|
packet sockets. See
|
|
<citerefentry><refentrytitle>listen</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
for details. Defaults to SOMAXCONN
|
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(128).</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
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<term><varname>BindToDevice=</varname></term>
|
|
<listitem><para>Specifies a network
|
|
interface name to bind this socket
|
|
to. If set, traffic will only be
|
|
accepted from the specified network
|
|
interfaces. This controls the
|
|
SO_BINDTODEVICE socket option (see
|
|
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for details). If this option is used,
|
|
an automatic dependency from this
|
|
socket unit on the network interface
|
|
device unit
|
|
(<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
is created.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>SocketUser=</varname></term>
|
|
<term><varname>SocketGroup=</varname></term>
|
|
|
|
<listitem><para>Takes a UNIX
|
|
user/group name. When specified,
|
|
all AF_UNIX sockets and FIFO nodes in
|
|
the file system are owned by the
|
|
specified user and group. If unset
|
|
(the default), the nodes are owned by
|
|
the root user/group (if run in system
|
|
context) or the invoking user/group
|
|
(if run in user context). If only a
|
|
user is specified but no group, then
|
|
the group is derived from the user's
|
|
default group.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>SocketMode=</varname></term>
|
|
<listitem><para>If listening on a file
|
|
system socket or FIFO, this option
|
|
specifies the file system access mode
|
|
used when creating the file
|
|
node. Takes an access mode in octal
|
|
notation. Defaults to
|
|
0666.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>DirectoryMode=</varname></term>
|
|
<listitem><para>If listening on a file
|
|
system socket or FIFO, the parent
|
|
directories are automatically created
|
|
if needed. This option specifies the
|
|
file system access mode used when
|
|
creating these directories. Takes an
|
|
access mode in octal
|
|
notation. Defaults to
|
|
0755.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Accept=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
argument. If true, a service instance
|
|
is spawned for each incoming
|
|
connection and only the connection
|
|
socket is passed to it. If false, all
|
|
listening sockets themselves are
|
|
passed to the started service unit,
|
|
and only one service unit is spawned
|
|
for all connections (also see
|
|
above). This value is ignored for
|
|
datagram sockets and FIFOs where a
|
|
single service unit unconditionally
|
|
handles all incoming traffic. Defaults
|
|
to <option>false</option>. For
|
|
performance reasons, it is recommended
|
|
to write new daemons only in a way
|
|
that is suitable for
|
|
<option>Accept=false</option>. A
|
|
daemon listening on an <constant>AF_UNIX</constant> socket
|
|
may, but does not need to, call
|
|
<citerefentry><refentrytitle>close</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
on the received socket before
|
|
exiting. However, it must not unlink
|
|
the socket from a file system. It
|
|
should not invoke
|
|
<citerefentry><refentrytitle>shutdown</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
on sockets it got with
|
|
<varname>Accept=false</varname>, but
|
|
it may do so for sockets it got with
|
|
<varname>Accept=true</varname> set.
|
|
Setting <varname>Accept=true</varname>
|
|
is mostly useful to allow daemons
|
|
designed for usage with
|
|
<citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
to work unmodified with systemd socket
|
|
activation.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>MaxConnections=</varname></term>
|
|
<listitem><para>The maximum number of
|
|
connections to simultaneously run
|
|
services instances for, when
|
|
<option>Accept=true</option> is
|
|
set. If more concurrent connections
|
|
are coming in, they will be refused
|
|
until at least one existing connection
|
|
is terminated. This setting has no
|
|
effect on sockets configured with
|
|
<option>Accept=false</option> or datagram
|
|
sockets. Defaults to
|
|
64.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>KeepAlive=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
argument. If true, the TCP/IP stack
|
|
will send a keep alive message after
|
|
2h (depending on the configuration of
|
|
<filename>/proc/sys/net/ipv4/tcp_keepalive_time</filename>)
|
|
for all TCP streams accepted on this
|
|
socket. This controls the SO_KEEPALIVE
|
|
socket option (see
|
|
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
and the <ulink
|
|
url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP
|
|
Keepalive HOWTO</ulink> for details.)
|
|
Defaults to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Priority=</varname></term>
|
|
<listitem><para>Takes an integer
|
|
argument controlling the priority for
|
|
all traffic sent from this
|
|
socket. This controls the SO_PRIORITY
|
|
socket option (see
|
|
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for details.).</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ReceiveBuffer=</varname></term>
|
|
<term><varname>SendBuffer=</varname></term>
|
|
<listitem><para>Takes an integer
|
|
argument controlling the receive or
|
|
send buffer sizes of this socket,
|
|
respectively. This controls the
|
|
SO_RCVBUF and SO_SNDBUF socket options
|
|
(see
|
|
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for details.). The usual suffixes K,
|
|
M, G are supported and are understood
|
|
to the base of 1024.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>IPTOS=</varname></term>
|
|
<listitem><para>Takes an integer
|
|
argument controlling the IP
|
|
Type-Of-Service field for packets
|
|
generated from this socket. This
|
|
controls the IP_TOS socket option (see
|
|
<citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for details.). Either a numeric string
|
|
or one of <option>low-delay</option>,
|
|
<option>throughput</option>,
|
|
<option>reliability</option> or
|
|
<option>low-cost</option> may be
|
|
specified.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>IPTTL=</varname></term>
|
|
<listitem><para>Takes an integer
|
|
argument controlling the IPv4
|
|
Time-To-Live/IPv6 Hop-Count field for
|
|
packets generated from this
|
|
socket. This sets the
|
|
IP_TTL/IPV6_UNICAST_HOPS socket
|
|
options (see
|
|
<citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
and
|
|
<citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for details.)</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Mark=</varname></term>
|
|
<listitem><para>Takes an integer
|
|
value. Controls the firewall mark of
|
|
packets generated by this socket. This
|
|
can be used in the firewall logic to
|
|
filter packets from this socket. This
|
|
sets the SO_MARK socket option. See
|
|
<citerefentry><refentrytitle>iptables</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
for details.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ReusePort=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
value. If true, allows multiple <citerefentry><refentrytitle>bind</refentrytitle><manvolnum>2</manvolnum></citerefentry>s
|
|
to this TCP or UDP port. This
|
|
controls the SO_REUSEPORT socket
|
|
option. See
|
|
<citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
for details.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>SmackLabel=</varname></term>
|
|
<term><varname>SmackLabelIPIn=</varname></term>
|
|
<term><varname>SmackLabelIPOut=</varname></term>
|
|
<listitem><para>Takes a string
|
|
value. Controls the extended
|
|
attributes
|
|
<literal>security.SMACK64</literal>,
|
|
<literal>security.SMACK64IPIN</literal>
|
|
and
|
|
<literal>security.SMACK64IPOUT</literal>,
|
|
respectively, i.e. the security label
|
|
of the FIFO, or the security label for
|
|
the incoming or outgoing connections
|
|
of the socket, respectively. See
|
|
<ulink
|
|
url="https://www.kernel.org/doc/Documentation/security/Smack.txt">Smack.txt</ulink>
|
|
for details.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>PipeSize=</varname></term>
|
|
<listitem><para>Takes a size in
|
|
bytes. Controls the pipe buffer size
|
|
of FIFOs configured in this socket
|
|
unit. See
|
|
<citerefentry><refentrytitle>fcntl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
|
|
for details. The usual suffixes K, M,
|
|
G are supported and are understood to
|
|
the base of 1024.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>MessageQueueMaxMessages=</varname>,
|
|
<varname>MessageQueueMessageSize=</varname></term>
|
|
<listitem><para>These two settings
|
|
take integer values and control the
|
|
mq_maxmsg field or the mq_msgsize field, respectively, when
|
|
creating the message queue. Note that
|
|
either none or both of these variables
|
|
need to be set. See
|
|
<citerefentry><refentrytitle>mq_setattr</refentrytitle><manvolnum>3</manvolnum></citerefentry>
|
|
for details.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>FreeBind=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
value. Controls whether the socket can
|
|
be bound to non-local IP
|
|
addresses. This is useful to configure
|
|
sockets listening on specific IP
|
|
addresses before those IP addresses
|
|
are successfully configured on a
|
|
network interface. This sets the
|
|
IP_FREEBIND socket option. For
|
|
robustness reasons it is recommended
|
|
to use this option whenever you bind a
|
|
socket to a specific IP
|
|
address. Defaults to <option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Transparent=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
value. Controls the IP_TRANSPARENT
|
|
socket option. Defaults to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Broadcast=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
value. This controls the SO_BROADCAST
|
|
socket option, which allows broadcast
|
|
datagrams to be sent from this
|
|
socket. Defaults to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>PassCredentials=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
value. This controls the SO_PASSCRED
|
|
socket option, which allows <constant>AF_UNIX</constant> sockets to
|
|
receive the credentials of the sending
|
|
process in an ancillary message.
|
|
Defaults to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>PassSecurity=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
value. This controls the SO_PASSSEC
|
|
socket option, which allows <constant>AF_UNIX</constant>
|
|
sockets to receive the security
|
|
context of the sending process in an
|
|
ancillary message. Defaults to
|
|
<option>false</option>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>TCPCongestion=</varname></term>
|
|
<listitem><para>Takes a string
|
|
value. Controls the TCP congestion
|
|
algorithm used by this socket. Should
|
|
be one of "westwood", "veno", "cubic",
|
|
"lp" or any other available algorithm
|
|
supported by the IP stack. This
|
|
setting applies only to stream
|
|
sockets.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ExecStartPre=</varname></term>
|
|
<term><varname>ExecStartPost=</varname></term>
|
|
<listitem><para>Takes one or more
|
|
command lines, which are executed
|
|
before or after the listening
|
|
sockets/FIFOs are created and
|
|
bound, respectively. The first token of the command
|
|
line must be an absolute filename,
|
|
then followed by arguments for the
|
|
process. Multiple command lines may be
|
|
specified following the same scheme as
|
|
used for
|
|
<varname>ExecStartPre=</varname> of
|
|
service unit files.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>ExecStopPre=</varname></term>
|
|
<term><varname>ExecStopPost=</varname></term>
|
|
<listitem><para>Additional commands
|
|
that are executed before or after
|
|
the listening sockets/FIFOs are closed
|
|
and removed, respectively. Multiple command lines
|
|
may be specified following the same
|
|
scheme as used for
|
|
<varname>ExecStartPre=</varname> of
|
|
service unit files.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>TimeoutSec=</varname></term>
|
|
<listitem><para>Configures the time to
|
|
wait for the commands specified in
|
|
<varname>ExecStartPre=</varname>,
|
|
<varname>ExecStartPost=</varname>,
|
|
<varname>ExecStopPre=</varname> and
|
|
<varname>ExecStopPost=</varname> to
|
|
finish. If a command does not exit
|
|
within the configured time, the socket
|
|
will be considered failed and be shut
|
|
down again. All commands still running,
|
|
will be terminated forcibly via
|
|
<constant>SIGTERM</constant>, and after another delay of
|
|
this time with <constant>SIGKILL</constant>. (See
|
|
<option>KillMode=</option> in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
|
|
Takes a unit-less value in seconds, or
|
|
a time span value such as "5min
|
|
20s". Pass 0 to disable the timeout
|
|
logic. Defaults to <varname>TimeoutStartSec=</varname> from the
|
|
manager configuration file.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Service=</varname></term>
|
|
<listitem><para>Specifies the service
|
|
unit name to activate on incoming
|
|
traffic. This setting is only allowed
|
|
for sockets with
|
|
<varname>Accept=no</varname>. It
|
|
defaults to the service that bears the
|
|
same name as the socket (with the
|
|
suffix replaced). In most cases, it
|
|
should not be necessary to use this
|
|
option.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>RemoveOnStop=</varname></term>
|
|
<listitem><para>Takes a boolean
|
|
argument. If enabled, any file nodes
|
|
created by this socket unit are
|
|
removed when it is stopped. This
|
|
applies to AF_UNIX sockets in the file
|
|
system, POSIX message queues, FIFOs,
|
|
as well as any symlinks to
|
|
them configured with
|
|
<varname>Symlinks=</varname>. Normally,
|
|
it should not be necessary to use this
|
|
option, and is not recommended as
|
|
services might continue to run after
|
|
the socket unit has been terminated
|
|
and it should still be possible to
|
|
communicate with them via their file
|
|
system node. Defaults to
|
|
off.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry>
|
|
<term><varname>Symlinks=</varname></term>
|
|
<listitem><para>Takes a list of file
|
|
system paths. The specified paths will
|
|
be created as symlinks to the AF_UNIX
|
|
socket path or FIFO path of this
|
|
socket unit. If this setting is used,
|
|
only one AF_UNIX socket in the file
|
|
system or one FIFO may be configured
|
|
for the socket unit. Use this option
|
|
to manage one or more symlinked alias
|
|
names for a socket, binding their
|
|
lifecycle together. Defaults to the
|
|
empty list.</para></listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
|
|
<para>Check
|
|
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
and
|
|
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
|
|
for more settings.</para>
|
|
|
|
</refsect1>
|
|
|
|
<refsect1>
|
|
<title>See Also</title>
|
|
<para>
|
|
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
|
|
</para>
|
|
|
|
<para>
|
|
For more extensive descriptions see the "systemd for Developers" series:
|
|
<ulink url="http://0pointer.de/blog/projects/socket-activation.html">Socket Activation</ulink>,
|
|
<ulink url="http://0pointer.de/blog/projects/socket-activation2.html">Socket Activation, part II</ulink>,
|
|
<ulink url="http://0pointer.de/blog/projects/inetd.html">Converting inetd Services</ulink>,
|
|
<ulink url="http://0pointer.de/blog/projects/socket-activated-containers.html">Socket Activated Internet Services and OS Containers</ulink>.
|
|
</para>
|
|
</refsect1>
|
|
|
|
</refentry>
|