1<?xml version='1.0'?>
2<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
5
6<refentry id="systemd-socket-activate"
7          xmlns:xi="http://www.w3.org/2001/XInclude">
8
9  <refentryinfo>
10    <title>systemd-socket-activate</title>
11    <productname>systemd</productname>
12  </refentryinfo>
13
14  <refmeta>
15    <refentrytitle>systemd-socket-activate</refentrytitle>
16    <manvolnum>1</manvolnum>
17  </refmeta>
18
19  <refnamediv>
20    <refname>systemd-socket-activate</refname>
21    <refpurpose>Test socket activation of daemons</refpurpose>
22  </refnamediv>
23
24  <refsynopsisdiv>
25    <cmdsynopsis>
26      <command>systemd-socket-activate</command>
27      <arg choice="opt" rep="repeat">OPTIONS</arg>
28      <arg choice="plain"><replaceable>daemon</replaceable></arg>
29      <arg choice="opt" rep="repeat">OPTIONS</arg>
30    </cmdsynopsis>
31  </refsynopsisdiv>
32
33  <refsect1>
34    <title>Description</title>
35
36    <para><command>systemd-socket-activate</command> may be used to launch a socket-activated service program from the
37    command line for testing purposes. It may also be used to launch individual instances of the service program per
38    connection.
39    </para>
40
41    <para>The daemon to launch and its options should be specified
42    after options intended for <command>systemd-socket-activate</command>.
43    </para>
44
45    <para>If the <option>--inetd</option> option is given, the socket file descriptor will be used as the standard
46    input and output of the launched process. Otherwise, standard input and output will be inherited, and sockets will
47    be passed through file descriptors 3 and higher. Sockets passed through <varname>$LISTEN_FDS</varname> to
48    <command>systemd-socket-activate</command> will be passed through to the daemon, in the original positions. Other sockets
49    specified with <option>--listen=</option> will use consecutive descriptors.  By default,
50    <command>systemd-socket-activate</command> listens on a stream socket, use <option>--datagram</option> and
51    <option>--seqpacket</option> to listen on datagram or sequential packet sockets instead (see below).
52    </para>
53  </refsect1>
54
55  <refsect1>
56    <title>Options</title>
57    <variablelist>
58      <varlistentry>
59        <term><option>-l <replaceable>address</replaceable></option></term>
60        <term><option>--listen=<replaceable>address</replaceable></option></term>
61
62        <listitem><para>Listen on this <replaceable>address</replaceable>.
63        Takes a string like <literal>2000</literal> or
64        <literal>127.0.0.1:2001</literal>.</para>
65        </listitem>
66      </varlistentry>
67
68      <varlistentry>
69        <term><option>-a</option></term>
70        <term><option>--accept</option></term>
71
72        <listitem><para>Launch an instance of the service program for each connection and pass the connection
73        socket.</para></listitem>
74      </varlistentry>
75
76      <varlistentry>
77        <term><option>-d</option></term>
78        <term><option>--datagram</option></term>
79
80        <listitem><para>Listen on a datagram socket (<constant>SOCK_DGRAM</constant>), instead of a stream socket
81        (<constant>SOCK_STREAM</constant>). May not be combined with <option>--seqpacket</option>.</para></listitem>
82      </varlistentry>
83
84      <varlistentry>
85        <term><option>--seqpacket</option></term>
86
87        <listitem><para>Listen on a sequential packet socket (<constant>SOCK_SEQPACKET</constant>), instead of a stream
88        socket (<constant>SOCK_STREAM</constant>). May not be combined with
89        <option>--datagram</option>.</para></listitem>
90      </varlistentry>
91
92      <varlistentry>
93        <term><option>--inetd</option></term>
94
95        <listitem><para>Use the inetd protocol for passing file descriptors, i.e. as standard input and standard
96        output, instead of the new-style protocol for passing file descriptors using <varname>$LISTEN_FDS</varname>
97        (see above).</para></listitem>
98      </varlistentry>
99
100      <varlistentry>
101        <term><option>-E <replaceable>VAR</replaceable><optional>=<replaceable>VALUE</replaceable></optional></option></term>
102        <term><option>--setenv=<replaceable>VAR</replaceable><optional>=<replaceable>VALUE</replaceable></optional></option></term>
103
104        <listitem><para>Add this variable to the environment of the
105        launched process. If <replaceable>VAR</replaceable> is
106        followed by <literal>=</literal>, assume that it is a
107        variable–value pair. Otherwise, obtain the value from the
108        environment of <command>systemd-socket-activate</command> itself.
109        </para></listitem>
110      </varlistentry>
111
112      <varlistentry>
113        <term><option>--fdname=</option><replaceable>NAME</replaceable><optional>:<replaceable>NAME</replaceable>…</optional></term>
114
115        <listitem><para>Specify names for the file descriptors passed. This is equivalent to setting
116        <varname>FileDescriptorName=</varname> in socket unit files, and enables use of
117        <citerefentry><refentrytitle>sd_listen_fds_with_names</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
118        Multiple entries may be specifies using separate options or by separating names with colons
119        (<literal>:</literal>) in one option. In case more names are given than descriptors, superfluous ones will be
120        ignored. In case less names are given than descriptors, the remaining file descriptors will be unnamed.
121        </para></listitem>
122      </varlistentry>
123
124      <xi:include href="standard-options.xml" xpointer="help" />
125      <xi:include href="standard-options.xml" xpointer="version" />
126    </variablelist>
127  </refsect1>
128
129  <refsect1>
130    <title>Environment variables</title>
131    <variablelist class='environment-variables'>
132      <varlistentry>
133        <term><varname>$LISTEN_FDS</varname></term>
134        <term><varname>$LISTEN_PID</varname></term>
135        <term><varname>$LISTEN_FDNAMES</varname></term>
136
137        <listitem><para>See
138        <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
139      </varlistentry>
140
141      <varlistentry>
142        <term><varname>$SYSTEMD_LOG_TARGET</varname></term>
143        <term><varname>$SYSTEMD_LOG_LEVEL</varname></term>
144        <term><varname>$SYSTEMD_LOG_TIME</varname></term>
145        <term><varname>$SYSTEMD_LOG_COLOR</varname></term>
146        <term><varname>$SYSTEMD_LOG_LOCATION</varname></term>
147
148        <listitem><para>Same as in
149        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para></listitem>
150      </varlistentry>
151    </variablelist>
152  </refsect1>
153
154  <refsect1>
155    <title>Examples</title>
156
157    <example>
158      <title>Run an echo server on port 2000</title>
159
160      <programlisting>$ systemd-socket-activate -l 2000 --inetd -a cat</programlisting>
161    </example>
162
163    <example>
164      <title>Run a socket-activated instance of <citerefentry><refentrytitle>systemd-journal-gatewayd</refentrytitle><manvolnum>8</manvolnum></citerefentry></title>
165
166      <programlisting>$ systemd-socket-activate -l 19531 /usr/lib/systemd/systemd-journal-gatewayd</programlisting>
167    </example>
168  </refsect1>
169
170  <refsect1>
171    <title>See Also</title>
172    <para>
173      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
174      <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
175      <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
176      <citerefentry><refentrytitle>systemd-run</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
177      <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
178      <citerefentry><refentrytitle>sd_listen_fds_with_names</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
179      <citerefentry project='man-pages'><refentrytitle>cat</refentrytitle><manvolnum>1</manvolnum></citerefentry>
180    </para>
181  </refsect1>
182</refentry>
183