systemd/man/systemd-socket-activate.xml

<?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">

<!--
  SPDX-License-Identifier: LGPL-2.1+

  This file is part of systemd.

  Copyright 2013 Zbigniew Jędrzejewski-Szmek

  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="systemd-socket-activate"
          xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>systemd-socket-activate</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Zbigniew</firstname>
        <surname>Jędrzejewski-Szmek</surname>
        <email>zbyszek@in.waw.pl</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-socket-activate</refentrytitle>
    <manvolnum>1</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-socket-activate</refname>
    <refpurpose>Test socket activation of daemons</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <cmdsynopsis>
      <command>systemd-socket-activate</command>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
      <arg choice="plain"><replaceable>daemon</replaceable></arg>
      <arg choice="opt" rep="repeat">OPTIONS</arg>
    </cmdsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>systemd-socket-activate</command> may be used to launch a socket-activated service program from the
    command line for testing purposes. It may also be used to launch individual instances of the service program per
    connection.
    </para>

    <para>The daemon to launch and its options should be specified
    after options intended for <command>systemd-socket-activate</command>.
    </para>

    <para>If the <option>--inetd</option> option is given, the socket file descriptor will be used as the standard
    input and output of the launched process. Otherwise, standard input and output will be inherited, and sockets will
    be passed through file descriptors 3 and higher. Sockets passed through <varname>$LISTEN_FDS</varname> to
    <command>systemd-socket-activate</command> will be passed through to the daemon, in the original positions. Other sockets
    specified with <option>--listen=</option> will use consecutive descriptors.  By default,
    <command>systemd-socket-activate</command> listens on a stream socket, use <option>--datagram</option> and
    <option>--seqpacket</option> to listen on datagram or sequential packet sockets instead (see below).
    </para>
  </refsect1>

  <refsect1>
    <title>Options</title>
    <variablelist>
      <varlistentry>
        <term><option>-l <replaceable>address</replaceable></option></term>
        <term><option>--listen=<replaceable>address</replaceable></option></term>

        <listitem><para>Listen on this <replaceable>address</replaceable>.
        Takes a string like <literal>2000</literal> or
        <literal>127.0.0.1:2001</literal>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-a</option></term>
        <term><option>--accept</option></term>

        <listitem><para>Launch an instance of the service program for each connection and pass the connection
        socket.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-d</option></term>
        <term><option>--datagram</option></term>

        <listitem><para>Listen on a datagram socket (<constant>SOCK_DGRAM</constant>), instead of a stream socket
        (<constant>SOCK_STREAM</constant>). May not be combined with <option>--seqpacket</option>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--seqpacket</option></term>

        <listitem><para>Listen on a sequential packet socket (<constant>SOCK_SEQPACKET</constant>), instead of a stream
        socket (<constant>SOCK_STREAM</constant>). May not be combined with
        <option>--datagram</option>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--inetd</option></term>

        <listitem><para>Use the inetd protocol for passing file descriptors, i.e. as standard input and standard
        output, instead of the new-style protocol for passing file descriptors using <varname>$LISTEN_FDS</varname>
        (see above).</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-E <replaceable>VAR</replaceable><optional>=<replaceable>VALUE</replaceable></optional></option></term>
        <term><option>--setenv=<replaceable>VAR</replaceable><optional>=<replaceable>VALUE</replaceable></optional></option></term>

        <listitem><para>Add this variable to the environment of the
        launched process. If <replaceable>VAR</replaceable> is
        followed by <literal>=</literal>, assume that it is a
        variable–value pair. Otherwise, obtain the value from the
        environment of <command>systemd-socket-activate</command> itself.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--fdname=</option><replaceable>NAME</replaceable><optional>:<replaceable>NAME</replaceable>…</optional></term>

        <listitem><para>Specify names for the file descriptors passed. This is equivalent to setting
        <varname>FileDescriptorName=</varname> in socket unit files, and enables use of
        <citerefentry><refentrytitle>sd_listen_fds_with_names</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
        Multiple entries may be specifies using separate options or by separating names with colons
        (<literal>:</literal>) in one option. In case more names are given than descriptors, superfluous ones will be
        ignored. In case less names are given than descriptors, the remaining file descriptors will be unnamed.
        </para></listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Environment variables</title>
    <variablelist class='environment-variables'>
      <varlistentry>
        <term><varname>$LISTEN_FDS</varname></term>
        <term><varname>$LISTEN_PID</varname></term>
        <term><varname>$LISTEN_FDNAMES</varname></term>

        <listitem><para>See
        <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><varname>$SYSTEMD_LOG_TARGET</varname></term>
        <term><varname>$SYSTEMD_LOG_LEVEL</varname></term>
        <term><varname>$SYSTEMD_LOG_COLOR</varname></term>
        <term><varname>$SYSTEMD_LOG_LOCATION</varname></term>

        <listitem><para>Same as in
        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Examples</title>

    <example>
      <title>Run an echo server on port 2000</title>

      <programlisting>$ systemd-socket-activate -l 2000 --inetd -a cat</programlisting>
    </example>

    <example>
      <title>Run a socket-activated instance of <citerefentry><refentrytitle>systemd-journal-gatewayd</refentrytitle><manvolnum>8</manvolnum></citerefentry></title>

      <programlisting>$ systemd-socket-activate -l 19531 /usr/lib/systemd/systemd-journal-gatewayd</programlisting>
    </example>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_listen_fds_with_names</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry project='man-pages'><refentrytitle>cat</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>
</refentry>