in the [Socket] section.</para>
<para>Additional options are listed in
- <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ which define the execution environment the
+ <option>ExecStartPre=</option>,
+ <option>ExecStartPost=</option>,
+ <option>ExecStopPre=</option> and
+ <option>ExecStoptPost=</option> commands are executed
+ in.</para>
<para>For each socket file a matching service file
(see
which services are instantiated for each incoming
connection.</para>
+ <para>Unless <varname>DefaultDependencies=</varname>
+ is set to <option>false</option>, socket units will
+ implicitly have dependencies of type
+ <varname>Requires=</varname> and
+ <varname>After=</varname> on
+ <filename>sysinit.target</filename> as well as
+ dependencies of type <varname>Conflicts=</varname> and
+ <varname>Before=</varname> on
+ <filename>shutdown.target</filename>. These ensure
+ that socket units pull in basic system
+ initialization, and are terminated cleanly prior to
+ system shutdown. Only sockets involved with early
+ boot or late system shutdown should disable this
+ option.</para>
+
<para>Socket units may be used to implement on-demand
starting of services, as well as parallelized starting
of services.</para>
+
+ <para>Note that the daemon software configured for
+ socket activation with socket units needs to be able
+ to accept sockets from systemd, either via systemd's
+ native socket passing interface (see
+ <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for details) or via the traditional
+ <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>-style
+ socket passing (i.e. sockets passed in via STDIN and
+ STDOUT, using <varname>StandardInput=socket</varname>
+ in the service file).</para>
</refsect1>
<refsect1>
directive above.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>ListenNetlink=</varname></term>
+ <listitem><para>Specifies a Netlink
+ family to create a socket for to
+ listen on. This expects a short string
+ referring to the AF_NETLINK family
+ name (such as <varname>audit</varname>
+ or <varname>kobject-uevent</varname>)
+ as argument, optionally suffixed by a
+ whitespace followed by a multicast
+ group integer. Behaviour otherwise is
+ very similar to the
+ <varname>ListenDatagram=</varname>
+ directive above.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>BindIPv6Only=</varname></term>
<listitem><para>Takes a one of
directories are automatically created
if needed. This option specifies the
file system access mode used when
- creating these directories. Defaults
- to 0755.</para></listitem>
+ creating these directories. Takes an
+ access mode in octal
+ notation. Defaults to
+ 0755.</para></listitem>
</varlistentry>
<varlistentry>
system socket of FIFO, this option
specifies the file system access mode
used when creating the file
- node. Defaults to
+ node. Takes an access mode in octal
+ notation. Defaults to
0666.</para></listitem>
</varlistentry>
address. 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 a command line,
- which is executed before (resp. after)
- the listening sockets/FIFOs are created and
+ <listitem><para>Takes one or more
+ command lines, which are executed
+ before (resp. after) the listening
+ sockets/FIFOs are created and
bound. The first token of the command
line must be an absolute file name,
then followed by arguments for the
- process. If specified more than once,
- all commands are executed one after
- the other, fully serialized. The use of
- these settings is optional.</para></listitem>
+ 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>
<listitem><para>Additional commands
that are executed before (resp. after)
the listening sockets/FIFOs are closed
- and removed. If specified more than
- once, all commands are executed one
- after the other, fully serialized. The use of
- these settings is optional.</para></listitem>
+ and removed. Multiple command lines
+ may be specified following the same
+ scheme as used for
+ <varname>ExecStartPre=</varname> of
+ service unit files.</para></listitem>
</varlistentry>
<varlistentry>
a time span value such as "5min
20s". Pass 0 to disable the timeout
logic. Defaults to
- 60s.</para></listitem>
+ 3min.</para></listitem>
</varlistentry>
<varlistentry>
processes of this socket unit shall be
killed. One of
<option>control-group</option>,
- <option>process-group</option>,
<option>process</option>,
<option>none</option>.</para>
<citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for details.</para></listitem>
</varlistentry>
+
+ <varlistentry>
+ <term><varname>KillSignal=</varname></term>
+ <listitem><para>Specifies which signal
+ to use when killing a process of this
+ socket. Defaults to SIGTERM.
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>SendSIGKILL=</varname></term>
+ <listitem><para>Specifies whether to
+ send SIGKILL to remaining processes
+ after a timeout, if the normal
+ shutdown procedure left processes of
+ the socket around. Takes a boolean
+ value. Defaults to "yes".
+ </para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>Service=</varname></term>
+ <listitem><para>Specifies the service
+ unit name to activate on incoming
+ traffic. This defaults to the service
+ that bears the same name as the socket
+ (ignoring the different suffixes). In
+ most cases it should not be necessary
+ to use this option.</para></listitem>
+ </varlistentry>
+
</variablelist>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <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>,
~ianmdlvl / elogind.git / blobdiff