man/systemd.socket.xml

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   9   Copyright 2010 Lennart Poettering
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  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>Socket unit configuration</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, and in
  80                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  81                 which define the way the processes are
  82                 terminated.</para>
  83
  84                 <para>For each socket file a matching service file
  85                 (see
  86                 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  87                 for details) must exist, describing the service to
  88                 start on incoming traffic on the socket. Depending on
  89                 the setting of <option>Accept=</option> (see below),
  90                 this must either be named like the socket unit, but
  91                 with the suffix replaced; or it must be a template
  92                 file named the same way. Example: a socket file
  93                 <filename>foo.socket</filename> needs a matching
  94                 service <filename>foo.service</filename> if
  95                 <option>Accept=false</option> is set. If
  96                 <option>Accept=true</option> is set a service template
  97                 file <filename>foo@.service</filename> must exist from
  98                 which services are instantiated for each incoming
  99                 connection.</para>
 100
 101                 <para>Unless <varname>DefaultDependencies=</varname>
 102                 is set to <option>false</option>, socket units will
 103                 implicitly have dependencies of type
 104                 <varname>Requires=</varname> and
 105                 <varname>After=</varname> on
 106                 <filename>sysinit.target</filename> as well as
 107                 dependencies of type <varname>Conflicts=</varname> and
 108                 <varname>Before=</varname> on
 109                 <filename>shutdown.target</filename>. These ensure
 110                 that socket units pull in basic system
 111                 initialization, and are terminated cleanly prior to
 112                 system shutdown. Only sockets involved with early
 113                 boot or late system shutdown should disable this
 114                 option.</para>
 115
 116                 <para>Socket units may be used to implement on-demand
 117                 starting of services, as well as parallelized starting
 118                 of services.</para>
 119
 120                 <para>Note that the daemon software configured for
 121                 socket activation with socket units needs to be able
 122                 to accept sockets from systemd, either via systemd's
 123                 native socket passing interface (see
 124                 <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 125                 for details) or via the traditional
 126                 <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>-style
 127                 socket passing (i.e. sockets passed in via STDIN and
 128                 STDOUT, using <varname>StandardInput=socket</varname>
 129                 in the service file).</para>
 130         </refsect1>
 131
 132         <refsect1>
 133                 <title>Options</title>
 134
 135                 <para>Socket files must include a [Socket] section,
 136                 which carries information about the socket or FIFO it
 137                 supervises. A number of options that may be used in
 138                 this section are shared with other unit types. These
 139                 options are documented in
 140                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 141                 and
 142                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 143                 options specific to the [Socket] section of socket
 144                 units are the following:</para>
 145
 146                 <variablelist>
 147                         <varlistentry>
 148                                 <term><varname>ListenStream=</varname></term>
 149                                 <term><varname>ListenDatagram=</varname></term>
 150                                 <term><varname>ListenSequentialPacket=</varname></term>
 151                                 <listitem><para>Specifies an address
 152                                 to listen on for a stream
 153                                 (SOCK_STREAM), datagram (SOCK_DGRAM),
 154                                 or sequential packet
 155                                 (SOCK_SEQPACKET) socket, respectively. The address
 156                                 can be written in various formats:</para>
 157
 158                                 <para>If the address starts with a
 159                                 slash (/), it is read as file system
 160                                 socket in the AF_UNIX socket
 161                                 family.</para>
 162
 163                                 <para>If the address starts with an
 164                                 at symbol (@) it is read as abstract
 165                                 namespace socket in the AF_UNIX
 166                                 family. The @ is replaced with a NUL
 167                                 character before binding. For details
 168                                 see
 169                                 <citerefentry><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
 170
 171                                 <para>If the address string is a
 172                                 single number it is read as port
 173                                 number to listen on via
 174                                 IPv6. Depending on the value of
 175                                 <varname>BindIPv6Only=</varname> (see below) this
 176                                 might result in the service being
 177                                 available via both IPv6 and IPv4 (default) or
 178                                 just via IPv6.
 179                                 </para>
 180
 181                                 <para>If the address string is a
 182                                 string in the format v.w.x.y:z it is
 183                                 read as IPv4 specifier for listening
 184                                 on an address v.w.x.y on a port
 185                                 z.</para>
 186
 187                                 <para>If the address string is a
 188                                 string in the format [x]:y it is read
 189                                 as IPv6 address x on a port y. Note
 190                                 that this might make the service
 191                                 available via IPv4, too, depending on
 192                                 the <varname>BindIPv6Only=</varname>
 193                                 setting (see below).
 194                                 </para>
 195
 196                                 <para>Note that SOCK_SEQPACKET
 197                                 (i.e. <varname>ListenSequentialPacket=</varname>)
 198                                 is only available for AF_UNIX
 199                                 sockets. SOCK_STREAM
 200                                 (i.e. <varname>ListenStream=</varname>)
 201                                 when used for IP sockets refers to TCP
 202                                 sockets, SOCK_DGRAM
 203                                 (i.e. <varname>ListenDatagram=</varname>)
 204                                 to UDP.</para>
 205
 206                                 <para>These options may be specified
 207                                 more than once in which case incoming
 208                                 traffic on any of the sockets will trigger
 209                                 service activation, and all listed
 210                                 sockets will be passed to the service,
 211                                 regardless whether there is incoming
 212                                 traffic on them or not.</para>
 213
 214                                 <para>If an IP address is used here, it
 215                                 is often desirable to listen on it
 216                                 before the interface it is configured
 217                                 on is up and running, and even
 218                                 regardless whether it will be up and
 219                                 running ever at all. To deal with this it is
 220                                 recommended to set the
 221                                 <varname>FreeBind=</varname> option
 222                                 described below.</para></listitem>
 223                         </varlistentry>
 224
 225                         <varlistentry>
 226                                 <term><varname>ListenFIFO=</varname></term>
 227                                 <listitem><para>Specifies a file
 228                                 system FIFO to listen on. This expects
 229                                 an absolute file system path as
 230                                 argument. Behavior otherwise is very
 231                                 similar to the
 232                                 <varname>ListenDatagram=</varname>
 233                                 directive above.</para></listitem>
 234                         </varlistentry>
 235
 236                         <varlistentry>
 237                                 <term><varname>ListenSpecial=</varname></term>
 238                                 <listitem><para>Specifies a special
 239                                 file in the file system to listen
 240                                 on. This expects an absolute file
 241                                 system path as argument. Behavior
 242                                 otherwise is very similar to the
 243                                 <varname>ListenFIFO=</varname>
 244                                 directive above. Use this to open
 245                                 character device nodes as well as
 246                                 special files in
 247                                 <filename>/proc</filename> and
 248                                 <filename>/sys</filename>.</para></listitem>
 249                         </varlistentry>
 250
 251                         <varlistentry>
 252                                 <term><varname>ListenNetlink=</varname></term>
 253                                 <listitem><para>Specifies a Netlink
 254                                 family to create a socket for to
 255                                 listen on. This expects a short string
 256                                 referring to the AF_NETLINK family
 257                                 name (such as <varname>audit</varname>
 258                                 or <varname>kobject-uevent</varname>)
 259                                 as argument, optionally suffixed by a
 260                                 whitespace followed by a multicast
 261                                 group integer. Behavior otherwise is
 262                                 very similar to the
 263                                 <varname>ListenDatagram=</varname>
 264                                 directive above.</para></listitem>
 265                         </varlistentry>
 266
 267                         <varlistentry>
 268                                 <term><varname>ListenMessageQueue=</varname></term>
 269                                 <listitem><para>Specifies a POSIX
 270                                 message queue name to listen on. This
 271                                 expects a valid message queue name
 272                                 (i.e. beginning with /). Behavior
 273                                 otherwise is very similar to the
 274                                 <varname>ListenFIFO=</varname>
 275                                 directive above. On Linux message
 276                                 queue descriptors are actually file
 277                                 descriptors and can be inherited
 278                                 between processes.</para></listitem>
 279                         </varlistentry>
 280
 281                         <varlistentry>
 282                                 <term><varname>BindIPv6Only=</varname></term>
 283                                 <listitem><para>Takes a one of
 284                                 <option>default</option>,
 285                                 <option>both</option> or
 286                                 <option>ipv6-only</option>. Controls
 287                                 the IPV6_V6ONLY socket option (see
 288                                 <citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 289                                 for details). If
 290                                 <option>both</option>, IPv6 sockets
 291                                 bound will be accessible via both IPv4
 292                                 and IPv6. If
 293                                 <option>ipv6-only</option>, they will
 294                                 be accessible via IPv6 only. If
 295                                 <option>default</option> (which is the
 296                                 default, surprise!) the system wide
 297                                 default setting is used, as controlled
 298                                 by
 299                                 <filename>/proc/sys/net/ipv6/bindv6only</filename>,
 300                                 which in turn defaults to the
 301                                 equivalent of
 302                                 <option>both</option>.</para>
 303                                 </listitem>
 304                         </varlistentry>
 305
 306                         <varlistentry>
 307                                 <term><varname>Backlog=</varname></term>
 308                                 <listitem><para>Takes an unsigned
 309                                 integer argument. Specifies the number
 310                                 of connections to queue that have not
 311                                 been accepted yet. This setting
 312                                 matters only for stream and sequential
 313                                 packet sockets. See
 314                                 <citerefentry><refentrytitle>listen</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 315                                 for details. Defaults to SOMAXCONN
 316                                 (128).</para></listitem>
 317                         </varlistentry>
 318
 319                         <varlistentry>
 320                                 <term><varname>BindToDevice=</varname></term>
 321                                 <listitem><para>Specifies a network
 322                                 interface name to bind this socket
 323                                 to. If set traffic will only be
 324                                 accepted from the specified network
 325                                 interfaces. This controls the
 326                                 SO_BINDTODEVICE socket option (see
 327                                 <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 328                                 for details). If this option is used,
 329                                 an automatic dependency from this
 330                                 socket unit on the network interface
 331                                 device unit
 332                                 (<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 333                                 is created.</para></listitem>
 334                         </varlistentry>
 335
 336                         <varlistentry>
 337                                 <term><varname>DirectoryMode=</varname></term>
 338                                 <listitem><para>If listening on a file
 339                                 system socket or FIFO, the parent
 340                                 directories are automatically created
 341                                 if needed. This option specifies the
 342                                 file system access mode used when
 343                                 creating these directories. Takes an
 344                                 access mode in octal
 345                                 notation. Defaults to
 346                                 0755.</para></listitem>
 347                         </varlistentry>
 348
 349                         <varlistentry>
 350                                 <term><varname>SocketMode=</varname></term>
 351                                 <listitem><para>If listening on a file
 352                                 system socket or FIFO, this option
 353                                 specifies the file system access mode
 354                                 used when creating the file
 355                                 node. Takes an access mode in octal
 356                                 notation. Defaults to
 357                                 0666.</para></listitem>
 358                         </varlistentry>
 359
 360                         <varlistentry>
 361                                 <term><varname>Accept=</varname></term>
 362                                 <listitem><para>Takes a boolean
 363                                 argument. If true, a service instance
 364                                 is spawned for each incoming
 365                                 connection and only the connection
 366                                 socket is passed to it. If false, all
 367                                 listening sockets themselves are
 368                                 passed to the started service unit,
 369                                 and only one service unit is spawned
 370                                 for all connections (also see
 371                                 above). This value is ignored for
 372                                 datagram sockets and FIFOs where
 373                                 a single service unit unconditionally
 374                                 handles all incoming traffic. Defaults
 375                                 to <option>false</option>. For
 376                                 performance reasons, it is recommended
 377                                 to write new daemons only in a way
 378                                 that is suitable for
 379                                 <option>Accept=false</option>. This
 380                                 option is mostly useful to allow
 381                                 daemons designed for usage with
 382                                 <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 383                                 to work unmodified with systemd socket
 384                                 activation.</para></listitem>
 385                         </varlistentry>
 386
 387                         <varlistentry>
 388                                 <term><varname>MaxConnections=</varname></term>
 389                                 <listitem><para>The maximum number of
 390                                 connections to simultaneously run
 391                                 services instances for, when
 392                                 <option>Accept=true</option> is
 393                                 set. If more concurrent connections
 394                                 are coming in, they will be refused
 395                                 until at least one existing connection
 396                                 is terminated. This setting has no
 397                                 effect for sockets configured with
 398                                 <option>Accept=false</option> or datagram
 399                                 sockets. Defaults to
 400                                 64.</para></listitem>
 401                         </varlistentry>
 402
 403                         <varlistentry>
 404                                 <term><varname>KeepAlive=</varname></term>
 405                                 <listitem><para>Takes a boolean
 406                                 argument. If true, the TCP/IP stack
 407                                 will send a keep alive message after
 408                                 2h (depending on the configuration of
 409                                 <filename>/proc/sys/net/ipv4/tcp_keepalive_time</filename>)
 410                                 for all TCP streams accepted on this
 411                                 socket. This controls the SO_KEEPALIVE
 412                                 socket option (see
 413                                 <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 414                                 and the <ulink
 415                                 url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP
 416                                 Keepalive HOWTO</ulink> for details.)
 417                                 Defaults to
 418                                 <option>false</option>.</para></listitem>
 419                         </varlistentry>
 420
 421                         <varlistentry>
 422                                 <term><varname>Priority=</varname></term>
 423                                 <listitem><para>Takes an integer
 424                                 argument controlling the priority for
 425                                 all traffic sent from this
 426                                 socket. This controls the SO_PRIORITY
 427                                 socket option (see
 428                                 <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 429                                 for details.).</para></listitem>
 430                         </varlistentry>
 431
 432                         <varlistentry>
 433                                 <term><varname>ReceiveBuffer=</varname></term>
 434                                 <term><varname>SendBuffer=</varname></term>
 435                                 <listitem><para>Takes an integer
 436                                 argument controlling the receive
 437                                 or send buffer sizes of this
 438                                 socket, respectively. This controls the SO_RCVBUF
 439                                 and SO_SNDBUF socket options (see
 440                                 <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 441                                 for details.).</para></listitem>
 442                         </varlistentry>
 443
 444                         <varlistentry>
 445                                 <term><varname>IPTOS=</varname></term>
 446                                 <listitem><para>Takes an integer
 447                                 argument controlling the IP
 448                                 Type-Of-Service field for packets
 449                                 generated from this socket. This
 450                                 controls the IP_TOS socket option (see
 451                                 <citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 452                                 for details.). Either a numeric string
 453                                 or one of <option>low-delay</option>,
 454                                 <option>throughput</option>,
 455                                 <option>reliability</option> or
 456                                 <option>low-cost</option> may be
 457                                 specified.</para></listitem>
 458                         </varlistentry>
 459
 460                         <varlistentry>
 461                                 <term><varname>IPTTL=</varname></term>
 462                                 <listitem><para>Takes an integer
 463                                 argument controlling the IPv4
 464                                 Time-To-Live/IPv6 Hop-Count field for
 465                                 packets generated from this
 466                                 socket. This sets the
 467                                 IP_TTL/IPV6_UNICAST_HOPS socket
 468                                 options (see
 469                                 <citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 470                                 and
 471                                 <citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 472                                 for details.)</para></listitem>
 473                         </varlistentry>
 474
 475                         <varlistentry>
 476                                 <term><varname>Mark=</varname></term>
 477                                 <listitem><para>Takes an integer
 478                                 value. Controls the firewall mark of
 479                                 packets generated by this socket. This
 480                                 can be used in the firewall logic to
 481                                 filter packets from this socket. This
 482                                 sets the SO_MARK socket option. See
 483                                 <citerefentry><refentrytitle>iptables</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 484                                 for details.</para></listitem>
 485                         </varlistentry>
 486
 487                         <varlistentry>
 488                                 <term><varname>SmackLabel=</varname></term>
 489                                 <term><varname>SmackLabelIPIn=</varname></term>
 490                                 <term><varname>SmackLabelIPOut=</varname></term>
 491                                 <listitem><para>Takes a string
 492                                 value. Controls the extended
 493                                 attributes
 494                                 <literal>security.SMACK64</literal>,
 495                                 <literal>security.SMACK64IPIN</literal>
 496                                 and
 497                                 <literal>security.SMACK64IPOUT</literal>,
 498                                 respectively, i.e. the security label
 499                                 of the FIFO, or the security label for
 500                                 the incoming or outgoing connections
 501                                 of the socket, respectively.  See
 502                                 <ulink
 503                                 url="https://www.kernel.org/doc/Documentation/security/Smack.txt">Smack.txt</ulink>
 504                                 for details.</para></listitem>
 505                         </varlistentry>
 506
 507                         <varlistentry>
 508                                 <term><varname>PipeSize=</varname></term>
 509                                 <listitem><para>Takes an integer
 510                                 value. Controls the pipe buffer size
 511                                 of FIFOs configured in this socket
 512                                 unit.  See
 513                                 <citerefentry><refentrytitle>fcntl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 514                                 for details.</para></listitem>
 515                         </varlistentry>
 516
 517                         <varlistentry>
 518                                 <term><varname>MessageQueueMaxMessages=</varname>,
 519                                 <varname>MessageQueueMessageSize=</varname></term>
 520                                 <listitem><para>These two settings
 521                                 take integer values and control the
 522                                 mq_maxmsg field or the mq_msgsize field, respectively, when
 523                                 creating the message queue. Note that
 524                                 either none or both of these variables
 525                                 need to be set. See
 526                                 <citerefentry><refentrytitle>mq_setattr</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 527                                 for details.</para></listitem>
 528                         </varlistentry>
 529
 530                         <varlistentry>
 531                                 <term><varname>FreeBind=</varname></term>
 532                                 <listitem><para>Takes a boolean
 533                                 value. Controls whether the socket can
 534                                 be bound to non-local IP
 535                                 addresses. This is useful to configure
 536                                 sockets listening on specific IP
 537                                 addresses before those IP addresses
 538                                 are successfully configured on a
 539                                 network interface. This sets the
 540                                 IP_FREEBIND socket option. For
 541                                 robustness reasons it is recommended
 542                                 to use this option whenever you bind a
 543                                 socket to a specific IP
 544                                 address. Defaults to <option>false</option>.</para></listitem>
 545                         </varlistentry>
 546
 547                         <varlistentry>
 548                                 <term><varname>Transparent=</varname></term>
 549                                 <listitem><para>Takes a boolean
 550                                 value. Controls the IP_TRANSPARENT
 551                                 socket option. Defaults to
 552                                 <option>false</option>.</para></listitem>
 553                         </varlistentry>
 554
 555                         <varlistentry>
 556                                 <term><varname>Broadcast=</varname></term>
 557                                 <listitem><para>Takes a boolean
 558                                 value. This controls the SO_BROADCAST
 559                                 socket option, which allows broadcast
 560                                 datagrams to be sent from this
 561                                 socket. Defaults to
 562                                 <option>false</option>.</para></listitem>
 563                         </varlistentry>
 564
 565                         <varlistentry>
 566                                 <term><varname>PassCredentials=</varname></term>
 567                                 <listitem><para>Takes a boolean
 568                                 value. This controls the SO_PASSCRED
 569                                 socket option, which allows AF_UNIX sockets to
 570                                 receive the credentials of the sending
 571                                 process in an ancillary message.
 572                                 Defaults to
 573                                 <option>false</option>.</para></listitem>
 574                         </varlistentry>
 575
 576                         <varlistentry>
 577                                 <term><varname>PassSecurity=</varname></term>
 578                                 <listitem><para>Takes a boolean
 579                                 value. This controls the SO_PASSSEC
 580                                 socket option, which allows AF_UNIX
 581                                 sockets to receive the security
 582                                 context of the sending process in an
 583                                 ancillary message.  Defaults to
 584                                 <option>false</option>.</para></listitem>
 585                         </varlistentry>
 586
 587                         <varlistentry>
 588                                 <term><varname>TCPCongestion=</varname></term>
 589                                 <listitem><para>Takes a string
 590                                 value. Controls the TCP congestion
 591                                 algorithm used by this socket. Should
 592                                 be one of "westwood", "veno", "cubic",
 593                                 "lp" or any other available algorithm
 594                                 supported by the IP stack. This
 595                                 setting applies only to stream
 596                                 sockets.</para></listitem>
 597                         </varlistentry>
 598
 599                         <varlistentry>
 600                                 <term><varname>ExecStartPre=</varname></term>
 601                                 <term><varname>ExecStartPost=</varname></term>
 602                                 <listitem><para>Takes one or more
 603                                 command lines, which are executed
 604                                 before or after the listening
 605                                 sockets/FIFOs are created and
 606                                 bound, respectively. The first token of the command
 607                                 line must be an absolute file name,
 608                                 then followed by arguments for the
 609                                 process. Multiple command lines may be
 610                                 specified following the same scheme as
 611                                 used for
 612                                 <varname>ExecStartPre=</varname> of
 613                                 service unit files.</para></listitem>
 614                         </varlistentry>
 615
 616                         <varlistentry>
 617                                 <term><varname>ExecStopPre=</varname></term>
 618                                 <term><varname>ExecStopPost=</varname></term>
 619                                 <listitem><para>Additional commands
 620                                 that are executed before or after
 621                                 the listening sockets/FIFOs are closed
 622                                 and removed, respectively. Multiple command lines
 623                                 may be specified following the same
 624                                 scheme as used for
 625                                 <varname>ExecStartPre=</varname> of
 626                                 service unit files.</para></listitem>
 627                         </varlistentry>
 628
 629                         <varlistentry>
 630                                 <term><varname>TimeoutSec=</varname></term>
 631                                 <listitem><para>Configures the time to
 632                                 wait for the commands specified in
 633                                 <varname>ExecStartPre=</varname>,
 634                                 <varname>ExecStartPost=</varname>,
 635                                 <varname>ExecStopPre=</varname> and
 636                                 <varname>ExecStopPost=</varname> to
 637                                 finish. If a command does not exit
 638                                 within the configured time, the socket
 639                                 will be considered failed and be shut
 640                                 down again. All commands still running,
 641                                 will be terminated forcibly via
 642                                 SIGTERM, and after another delay of
 643                                 this time with SIGKILL. (See
 644                                 <option>KillMode=</option> in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>.)
 645                                 Takes a unit-less value in seconds, or
 646                                 a time span value such as "5min
 647                                 20s". Pass 0 to disable the timeout
 648                                 logic. Defaults to
 649                                 90s.</para></listitem>
 650                         </varlistentry>
 651
 652                         <varlistentry>
 653                                 <term><varname>Service=</varname></term>
 654                                 <listitem><para>Specifies the service
 655                                 unit name to activate on incoming
 656                                 traffic. This defaults to the service
 657                                 that bears the same name as the socket
 658                                 (ignoring the different suffixes). In
 659                                 most cases it should not be necessary
 660                                 to use this option.</para></listitem>
 661                         </varlistentry>
 662
 663                 </variablelist>
 664
 665                 <para>Check
 666                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 667                 and
 668                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 669                 for more settings.</para>
 670
 671         </refsect1>
 672
 673         <refsect1>
 674                   <title>See Also</title>
 675                   <para>
 676                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 677                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 678                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 679                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 680                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 681                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 682                   </para>
 683         </refsect1>
 684
 685 </refentry>