chiark / gitweb /
logind: simplify session_activate() a bit
[elogind.git] / man / systemd.socket.xml
1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <?xml-stylesheet type="text/xsl" href="http://docbook.sourceforge.net/release/xsl/current/xhtml/docbook.xsl"?>
3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
4         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5
6 <!--
7   This file is part of systemd.
8
9   Copyright 2010 Lennart Poettering
10
11   systemd is free software; you can redistribute it and/or modify it
12   under the terms of the GNU General Public License as published by
13   the Free Software Foundation; either version 2 of the License, or
14   (at your option) any later version.
15
16   systemd is distributed in the hope that it will be useful, but
17   WITHOUT ANY WARRANTY; without even the implied warranty of
18   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19   General Public License for more details.
20
21   You should have received a copy of the GNU General Public License
22   along with systemd; If not, see <http://www.gnu.org/licenses/>.
23 -->
24
25 <refentry id="systemd.socket">
26         <refentryinfo>
27                 <title>systemd.socket</title>
28                 <productname>systemd</productname>
29
30                 <authorgroup>
31                         <author>
32                                 <contrib>Developer</contrib>
33                                 <firstname>Lennart</firstname>
34                                 <surname>Poettering</surname>
35                                 <email>lennart@poettering.net</email>
36                         </author>
37                 </authorgroup>
38         </refentryinfo>
39
40         <refmeta>
41                 <refentrytitle>systemd.socket</refentrytitle>
42                 <manvolnum>5</manvolnum>
43         </refmeta>
44
45         <refnamediv>
46                 <refname>systemd.socket</refname>
47                 <refpurpose>systemd socket configuration files</refpurpose>
48         </refnamediv>
49
50         <refsynopsisdiv>
51                 <para><filename>systemd.socket</filename></para>
52         </refsynopsisdiv>
53
54         <refsect1>
55                 <title>Description</title>
56
57                 <para>A unit configuration file whose name ends in
58                 <filename>.socket</filename> encodes information about
59                 an IPC or network socket or a file system FIFO
60                 controlled and supervised by systemd, for socket-based
61                 activation.</para>
62
63                 <para>This man page lists the configuration options
64                 specific to this unit type. See
65                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
66                 for the common options of all unit configuration
67                 files. The common configuration items are configured
68                 in the generic [Unit] and [Install] sections. The
69                 socket specific configuration options are configured
70                 in the [Socket] section.</para>
71
72                 <para>Additional options are listed in
73                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
74                 which define the execution environment the
75                 <option>ExecStartPre=</option>,
76                 <option>ExecStartPost=</option>,
77                 <option>ExecStopPre=</option> and
78                 <option>ExecStoptPost=</option> commands are executed
79                 in.</para>
80
81                 <para>For each socket file a matching service file
82                 (see
83                 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
84                 for details) must exist, describing the service to
85                 start on incoming traffic on the socket. Depending on
86                 the setting of <option>Accept=</option> (see below),
87                 this must either be named like the socket unit, but
88                 with the suffix replaced; or it must be a template
89                 file named the same way. Example: a socket file
90                 <filename>foo.socket</filename> needs a matching
91                 service <filename>foo.service</filename> if
92                 <option>Accept=false</option> is set. If
93                 <option>Accept=true</option> is set a service template
94                 file <filename>foo@.service</filename> must exist from
95                 which services are instantiated for each incoming
96                 connection.</para>
97
98                 <para>Unless <varname>DefaultDependencies=</varname>
99                 is set to <option>false</option>, socket units will
100                 implicitly have dependencies of type
101                 <varname>Requires=</varname> and
102                 <varname>After=</varname> on
103                 <filename>sysinit.target</filename> as well as
104                 dependencies of type <varname>Conflicts=</varname> and
105                 <varname>Before=</varname> on
106                 <filename>shutdown.target</filename>. These ensure
107                 that socket units pull in basic system
108                 initialization, and are terminated cleanly prior to
109                 system shutdown. Only sockets involved with early
110                 boot or late system shutdown should disable this
111                 option.</para>
112
113                 <para>Socket units may be used to implement on-demand
114                 starting of services, as well as parallelized starting
115                 of services.</para>
116
117                 <para>Note that the daemon software configured for
118                 socket activation with socket units needs to be able
119                 to accept sockets from systemd, either via systemd's
120                 native socket passing interface (see
121                 <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
122                 for details) or via the traditional
123                 <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>-style
124                 socket passing (i.e. sockets passed in via STDIN and
125                 STDOUT, using <varname>StandardInput=socket</varname>
126                 in the service file).</para>
127         </refsect1>
128
129         <refsect1>
130                 <title>Options</title>
131
132                 <para>Socket files must include a [Socket] section,
133                 which carries information about the socket or FIFO it
134                 supervises. A number of options that may be used in
135                 this section are shared with other unit types. These
136                 options are documented in
137                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
138                 options specific to the [Socket] section of socket
139                 units are the following:</para>
140
141                 <variablelist>
142                         <varlistentry>
143                                 <term><varname>ListenStream=</varname></term>
144                                 <term><varname>ListenDatagram=</varname></term>
145                                 <term><varname>ListenSequentialPacket=</varname></term>
146                                 <listitem><para>Specifies an address
147                                 to listen on for a stream
148                                 (SOCK_STREAM), datagram (SOCK_DGRAM)
149                                 resp. sequential packet
150                                 (SOCK_SEQPACKET) socket. The address
151                                 can be written in various formats:</para>
152
153                                 <para>If the address starts with a
154                                 slash (/), it is read as file system
155                                 socket in the AF_UNIX socket
156                                 family.</para>
157
158                                 <para>If the address starts with an
159                                 at symbol (@) it is read as abstract
160                                 namespace socket in the AF_UNIX
161                                 family. The @ is replaced with a NUL
162                                 character before binding. For details
163                                 see
164                                 <citerefentry><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
165
166                                 <para>If the address string is a
167                                 single number it is read as port
168                                 number to listen on for both IPv4 and
169                                 IPv6.</para>
170
171                                 <para>If the address string is a
172                                 string in the format v.w.x.y:z it is
173                                 read as IPv4 specifier for listening
174                                 on an address v.w.x.y on a port
175                                 z.</para>
176
177                                 <para>If the address string is a
178                                 string in the format [x]:y it is read
179                                 as IPv6 address x on a port y.</para>
180
181                                 <para>Note that SOCK_SEQPACKET
182                                 (i.e. <varname>ListenSequentialPacket=</varname>)
183                                 is only available for AF_UNIX
184                                 sockets. SOCK_STREAM
185                                 (i.e. <varname>ListenStream=</varname>)
186                                 when used for IP sockets refers to TCP
187                                 sockets, SOCK_DGRAM
188                                 (i.e. <varname>ListenDatagram=</varname>)
189                                 to UDP.</para>
190
191                                 <para>These options may be specified
192                                 more than once in which case incoming
193                                 traffic on any of the sockets will trigger
194                                 service activation, and all listed
195                                 sockets will be passed to the service,
196                                 regardless whether there is incoming
197                                 traffic on them or not.</para>
198
199                                 <para>If an IP address is used here, it
200                                 is often desirable to listen on it
201                                 before the interface it is configured
202                                 on is up and running, and even
203                                 regardless whether it will be up and
204                                 running ever at all. To deal with this it is
205                                 recommended to set the
206                                 <varname>FreeBind=</varname> option
207                                 described below.</para></listitem>
208                         </varlistentry>
209
210                         <varlistentry>
211                                 <term><varname>ListenFIFO=</varname></term>
212                                 <listitem><para>Specifies a file
213                                 system FIFO to listen on. This expects
214                                 an absolute file system path as
215                                 argument. Behaviour otherwise is very
216                                 similar to the
217                                 <varname>ListenDatagram=</varname>
218                                 directive above.</para></listitem>
219                         </varlistentry>
220
221                         <varlistentry>
222                                 <term><varname>ListenSpecial=</varname></term>
223                                 <listitem><para>Specifies a special
224                                 file in the file system to listen
225                                 on. This expects an absolute file
226                                 system path as argument. Behaviour
227                                 otherwise is very similar to the
228                                 <varname>ListenFIFO=</varname>
229                                 directive above. Use this to open
230                                 character device nodes as well as
231                                 special files in
232                                 <filename>/proc</filename> and
233                                 <filename>/sys</filename>.</para></listitem>
234                         </varlistentry>
235
236                         <varlistentry>
237                                 <term><varname>ListenNetlink=</varname></term>
238                                 <listitem><para>Specifies a Netlink
239                                 family to create a socket for to
240                                 listen on. This expects a short string
241                                 referring to the AF_NETLINK family
242                                 name (such as <varname>audit</varname>
243                                 or <varname>kobject-uevent</varname>)
244                                 as argument, optionally suffixed by a
245                                 whitespace followed by a multicast
246                                 group integer. Behaviour otherwise is
247                                 very similar to the
248                                 <varname>ListenDatagram=</varname>
249                                 directive above.</para></listitem>
250                         </varlistentry>
251
252                         <varlistentry>
253                                 <term><varname>ListenMessageQueue=</varname></term>
254                                 <listitem><para>Specifies a POSIX
255                                 message queue name to listen on. This
256                                 expects a valid message queue name
257                                 (i.e. beginning with /). Behaviour
258                                 otherwise is very similar to the
259                                 <varname>ListenFIFO=</varname>
260                                 directive above. On Linux message
261                                 queue descriptors are actually file
262                                 descriptors and can be inherited
263                                 between processes.</para></listitem>
264                         </varlistentry>
265
266                         <varlistentry>
267                                 <term><varname>BindIPv6Only=</varname></term>
268                                 <listitem><para>Takes a one of
269                                 <option>default</option>,
270                                 <option>both</option> or
271                                 <option>ipv6-only</option>. Controls
272                                 the IPV6_V6ONLY socket option (see
273                                 <citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>
274                                 for details). If
275                                 <option>both</option>, IPv6 sockets
276                                 bound will be accessible via both IPv4
277                                 and IPv6. If
278                                 <option>ipv6-only</option>, they will
279                                 be accessible via IPv6 only. If
280                                 <option>default</option> (which is the
281                                 default, surprise!) the system wide
282                                 default setting is used, as controlled
283                                 by
284                                 <filename>/proc/sys/net/ipv6/bindv6only</filename>.</para>
285                                 </listitem>
286                         </varlistentry>
287
288                         <varlistentry>
289                                 <term><varname>Backlog=</varname></term>
290                                 <listitem><para>Takes an unsigned
291                                 integer argument. Specifies the number
292                                 of connections to queue that have not
293                                 been accepted yet. This setting
294                                 matters only for stream and sequential
295                                 packet sockets. See
296                                 <citerefentry><refentrytitle>listen</refentrytitle><manvolnum>2</manvolnum></citerefentry>
297                                 for details. Defaults to SOMAXCONN
298                                 (128).</para></listitem>
299                         </varlistentry>
300
301                         <varlistentry>
302                                 <term><varname>BindToDevice=</varname></term>
303                                 <listitem><para>Specifies a network
304                                 interface name to bind this socket
305                                 to. If set traffic will only be
306                                 accepted from the specified network
307                                 interfaces. This controls the
308                                 SO_BINDTODEVICE socket option (see
309                                 <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
310                                 for details). If this option is used,
311                                 an automatic dependency from this
312                                 socket unit on the network interface
313                                 device unit
314                                 (<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>
315                                 is created.</para></listitem>
316                         </varlistentry>
317
318                         <varlistentry>
319                                 <term><varname>DirectoryMode=</varname></term>
320                                 <listitem><para>If listening on a file
321                                 system socket of FIFO, the parent
322                                 directories are automatically created
323                                 if needed. This option specifies the
324                                 file system access mode used when
325                                 creating these directories. Takes an
326                                 access mode in octal
327                                 notation. Defaults to
328                                 0755.</para></listitem>
329                         </varlistentry>
330
331                         <varlistentry>
332                                 <term><varname>SocketMode=</varname></term>
333                                 <listitem><para>If listening on a file
334                                 system socket of FIFO, this option
335                                 specifies the file system access mode
336                                 used when creating the file
337                                 node. Takes an access mode in octal
338                                 notation. Defaults to
339                                 0666.</para></listitem>
340                         </varlistentry>
341
342                         <varlistentry>
343                                 <term><varname>Accept=</varname></term>
344                                 <listitem><para>Takes a boolean
345                                 argument. If true, a service instance
346                                 is spawned for each incoming
347                                 connection and only the connection
348                                 socket is passed to it. If false, all
349                                 listening sockets themselves are
350                                 passed to the started service unit,
351                                 and only one service unit is spawned
352                                 for all connections (also see
353                                 above). This value is ignored for
354                                 datagram sockets and FIFOs where
355                                 a single service unit unconditionally
356                                 handles all incoming traffic. Defaults
357                                 to <option>false</option>. For
358                                 performance reasons, it is recommended
359                                 to write new daemons only in a way
360                                 that is suitable for
361                                 <option>Accept=false</option>. This
362                                 option is mostly useful to allow
363                                 daemons designed for usage with
364                                 <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
365                                 to work unmodified with systemd socket
366                                 activation.</para></listitem>
367                         </varlistentry>
368
369                         <varlistentry>
370                                 <term><varname>MaxConnections=</varname></term>
371                                 <listitem><para>The maximum number of
372                                 connections to simultaneously run
373                                 services instances for, when
374                                 <option>Accept=true</option> is
375                                 set. If more concurrent connections
376                                 are coming in, they will be refused
377                                 until at least one existing connection
378                                 is terminated. This setting has no
379                                 effect for sockets configured with
380                                 <option>Accept=no</option> or datagram
381                                 sockets. Defaults to
382                                 64.</para></listitem>
383                         </varlistentry>
384
385                         <varlistentry>
386                                 <term><varname>KeepAlive=</varname></term>
387                                 <listitem><para>Takes a boolean
388                                 argument. If true, the TCP/IP stack
389                                 will send a keep alive message after
390                                 2h (depending on the configuration of
391                                 <filename>/proc/sys/net/ipv4/tcp_keepalive_time</filename>)
392                                 for all TCP streams accepted on this
393                                 socket. This controls the SO_KEEPALIVE
394                                 socket option (see
395                                 <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
396                                 and the <ulink
397                                 url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP
398                                 Keepalive HOWTO</ulink> for details.)
399                                 Defaults to
400                                 <option>false</option>.</para></listitem>
401                         </varlistentry>
402
403                         <varlistentry>
404                                 <term><varname>Priority=</varname></term>
405                                 <listitem><para>Takes an integer
406                                 argument controlling the priority for
407                                 all traffic sent from this
408                                 socket. This controls the SO_PRIORITY
409                                 socket option (see
410                                 <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
411                                 for details.).</para></listitem>
412                         </varlistentry>
413
414                         <varlistentry>
415                                 <term><varname>ReceiveBuffer=</varname></term>
416                                 <term><varname>SendBuffer=</varname></term>
417                                 <listitem><para>Takes an integer
418                                 argument controlling the receive
419                                 resp. send buffer sizes of this
420                                 socket. This controls the SO_RCVBUF
421                                 resp. SO_SNDBUF socket options (see
422                                 <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
423                                 for details.).</para></listitem>
424                         </varlistentry>
425
426                         <varlistentry>
427                                 <term><varname>IPTOS=</varname></term>
428                                 <listitem><para>Takes an integer
429                                 argument controlling the IP
430                                 Type-Of-Service field for packets
431                                 generated from this socket. This
432                                 controls the IP_TOS socket option (see
433                                 <citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>
434                                 for details.). Either a numeric string
435                                 or one of <option>low-delay</option>,
436                                 <option>throughput</option>,
437                                 <option>reliability</option> or
438                                 <option>low-cost</option> may be
439                                 specified.</para></listitem>
440                         </varlistentry>
441
442                         <varlistentry>
443                                 <term><varname>IPTTL=</varname></term>
444                                 <listitem><para>Takes an integer
445                                 argument controlling the IPv4
446                                 Time-To-Live/IPv6 Hop-Count field for
447                                 packets generated from this
448                                 socket. This sets the
449                                 IP_TTL/IPV6_UNICAST_HOPS socket
450                                 options (see
451                                 <citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>
452                                 and
453                                 <citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>
454                                 for details.)</para></listitem>
455                         </varlistentry>
456
457                         <varlistentry>
458                                 <term><varname>Mark=</varname></term>
459                                 <listitem><para>Takes an integer
460                                 value. Controls the firewall mark of
461                                 packets generated by this socket. This
462                                 can be used in the firewall logic to
463                                 filter packets from this socket. This
464                                 sets the SO_MARK socket option. See
465                                 <citerefentry><refentrytitle>iptables</refentrytitle><manvolnum>8</manvolnum></citerefentry>
466                                 for details.</para></listitem>
467                         </varlistentry>
468
469                         <varlistentry>
470                                 <term><varname>PipeSize=</varname></term>
471                                 <listitem><para>Takes an integer
472                                 value. Controls the pipe buffer size
473                                 of FIFOs configured in this socket
474                                 unit.  See
475                                 <citerefentry><refentrytitle>fcntl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
476                                 for details.</para></listitem>
477                         </varlistentry>
478
479                         <varlistentry>
480                                 <term><varname>MessageQueueMaxMessages=</varname>,
481                                 <varname>MessageQueueMessageSize=</varname></term>
482                                 <listitem><para>These two settings
483                                 take integer values and control the
484                                 mq_maxmsg resp. mq_msgsize field when
485                                 creating the message queue. Note that
486                                 either none or both of these variables
487                                 need to be set. See
488                                 <citerefentry><refentrytitle>mq_setattr</refentrytitle><manvolnum>3</manvolnum></citerefentry>
489                                 for details.</para></listitem>
490                         </varlistentry>
491
492                         <varlistentry>
493                                 <term><varname>FreeBind=</varname></term>
494                                 <listitem><para>Takes a boolean
495                                 value. Controls whether the socket can
496                                 be bound to non-local IP
497                                 addresses. This is useful to configure
498                                 sockets listening on specific IP
499                                 addresses before those IP addresses
500                                 are successfully configured on a
501                                 network interface. This sets the
502                                 IP_FREEBIND socket option. For
503                                 robustness reasons it is recommended
504                                 to use this option whenever you bind a
505                                 socket to a specific IP
506                                 address. Defaults to <option>false</option>.</para></listitem>
507                         </varlistentry>
508
509                         <varlistentry>
510                                 <term><varname>Transparent=</varname></term>
511                                 <listitem><para>Takes a boolean
512                                 value. Controls the IP_TRANSPARENT
513                                 socket option. Defaults to
514                                 <option>false</option>.</para></listitem>
515                         </varlistentry>
516
517                         <varlistentry>
518                                 <term><varname>Broadcast=</varname></term>
519                                 <listitem><para>Takes a boolean
520                                 value. This controls the SO_BROADCAST
521                                 socket option, which allows broadcast
522                                 datagrams to be sent from this
523                                 socket. Defaults to
524                                 <option>false</option>.</para></listitem>
525                         </varlistentry>
526
527                         <varlistentry>
528                                 <term><varname>PassCredentials=</varname></term>
529                                 <listitem><para>Takes a boolean
530                                 value. This controls the SO_PASSCRED
531                                 socket option, which allows UNIX sockets to
532                                 receive the credentials of the sending
533                                 process in an ancillary message.
534                                 Defaults to
535                                 <option>false</option>.</para></listitem>
536                         </varlistentry>
537
538                         <varlistentry>
539                                 <term><varname>TCPCongestion=</varname></term>
540                                 <listitem><para>Takes a string
541                                 value. Controls the TCP congestion
542                                 algorithm used by this socket. Should
543                                 be one of "westwood", "veno", "cubic",
544                                 "lp" or any other available algorithm
545                                 supported by the IP stack. This
546                                 setting applies only to stream
547                                 sockets.</para></listitem>
548                         </varlistentry>
549
550                         <varlistentry>
551                                 <term><varname>ExecStartPre=</varname></term>
552                                 <term><varname>ExecStartPost=</varname></term>
553                                 <listitem><para>Takes one or more
554                                 command lines, which are executed
555                                 before (resp. after) the listening
556                                 sockets/FIFOs are created and
557                                 bound. The first token of the command
558                                 line must be an absolute file name,
559                                 then followed by arguments for the
560                                 process. Multiple command lines may be
561                                 specified following the same scheme as
562                                 used for
563                                 <varname>ExecStartPre=</varname> of
564                                 service unit files.</para></listitem>
565                         </varlistentry>
566
567                         <varlistentry>
568                                 <term><varname>ExecStopPre=</varname></term>
569                                 <term><varname>ExecStopPost=</varname></term>
570                                 <listitem><para>Additional commands
571                                 that are executed before (resp. after)
572                                 the listening sockets/FIFOs are closed
573                                 and removed. Multiple command lines
574                                 may be specified following the same
575                                 scheme as used for
576                                 <varname>ExecStartPre=</varname> of
577                                 service unit files.</para></listitem>
578                         </varlistentry>
579
580                         <varlistentry>
581                                 <term><varname>TimeoutSec=</varname></term>
582                                 <listitem><para>Configures the time to
583                                 wait for the commands specified in
584                                 <varname>ExecStartPre=</varname>,
585                                 <varname>ExecStartPost=</varname>,
586                                 <varname>ExecStopPre=</varname> and
587                                 <varname>ExecStopPost=</varname> to
588                                 finish. If a command does not exit
589                                 within the configured time, the socket
590                                 will be considered failed and be shut
591                                 down again. All commands still running,
592                                 will be terminated forcibly via
593                                 SIGTERM, and after another delay of
594                                 this time with SIGKILL. (See
595                                 <option>KillMode=</option> below.)
596                                 Takes a unit-less value in seconds, or
597                                 a time span value such as "5min
598                                 20s". Pass 0 to disable the timeout
599                                 logic. Defaults to
600                                 90s.</para></listitem>
601                         </varlistentry>
602
603                         <varlistentry>
604                                 <term><varname>KillMode=</varname></term>
605                                 <listitem><para>Specifies how
606                                 processes of this socket unit shall be
607                                 killed. One of
608                                 <option>control-group</option>,
609                                 <option>process</option>,
610                                 <option>none</option>.</para>
611
612                                 <para>This option is mostly equivalent
613                                 to the <option>KillMode=</option>
614                                 option of service files. See
615                                 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
616                                 for details.</para></listitem>
617                         </varlistentry>
618
619                         <varlistentry>
620                                 <term><varname>KillSignal=</varname></term>
621                                 <listitem><para>Specifies which signal
622                                 to use when killing a process of this
623                                 socket. Defaults to SIGTERM.
624                                 </para></listitem>
625                         </varlistentry>
626
627                         <varlistentry>
628                                 <term><varname>SendSIGKILL=</varname></term>
629                                 <listitem><para>Specifies whether to
630                                 send SIGKILL to remaining processes
631                                 after a timeout, if the normal
632                                 shutdown procedure left processes of
633                                 the socket around. Takes a boolean
634                                 value. Defaults to "yes".
635                                 </para></listitem>
636                         </varlistentry>
637
638                         <varlistentry>
639                                 <term><varname>Service=</varname></term>
640                                 <listitem><para>Specifies the service
641                                 unit name to activate on incoming
642                                 traffic. This defaults to the service
643                                 that bears the same name as the socket
644                                 (ignoring the different suffixes). In
645                                 most cases it should not be necessary
646                                 to use this option.</para></listitem>
647                         </varlistentry>
648
649                 </variablelist>
650         </refsect1>
651
652         <refsect1>
653                   <title>See Also</title>
654                   <para>
655                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
656                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
657                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
658                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
659                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
660                   </para>
661         </refsect1>
662
663 </refentry>