projects / thirdparty / systemd.git / blame
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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 .socket | |
| 58 | encodes information about an IPC or network socket or | |
| 59 | a file system FIFO controlled and supervised by systemd, | |
| 60 | for socket-based activation.</para> | |
| 61 | ||
| 62 | <para>This man page lists the configuration options | |
| 63 | specific to this unit type. See | |
| 64 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
| 65 | for the common options of all unit configuration | |
| 66 | files. The common configuration items are configured | |
| 67 | in the generic [Unit] and [Install] sections. The | |
| 68 | service specific configuration options are configured | |
| 69 | in the [Socket] section.</para> | |
| 70 | ||
| 71 | <para>Additional options are listed in | |
| 72 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> | |
| 73 | ||
| 74 | <para>For each socket file a matching service file (see <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details) | |
| 75 | must exist, describing the service to start on | |
| 76 | incoming traffic on the socket. Depending on the | |
| 77 | setting of <option>Accept=</option> (see below) this | |
| 78 | must either be named like the socket unit, but with | |
| 79 | the suffix replaced; or it must be a template file | |
| 80 | named the same way. Example: a socket file | |
| 81 | <filename>foo.socket</filename> needs a matching | |
| 82 | service <filename>foo.service</filename> if | |
| 83 | <option>Accept=false</option> is set. If | |
| 84 | <option>Accept=true</option> is set a service template | |
| 85 | file <filename>foo@.service</filename> must exist from | |
| 86 | which services are instantiated for each incoming | |
| 87 | connection.</para> | |
| 88 | </refsect1> | |
| 89 | ||
| 90 | <refsect1> | |
| 91 | <title>Options</title> | |
| 92 | ||
| 93 | <para>Socket files must include a [Socket] section, | |
| 94 | which carries information about the socket or FIFO it | |
| 95 | supervises. A number of options that may be used in | |
| 96 | this section are shared with other unit types. These | |
| 97 | options are documented in | |
| 98 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The | |
| 99 | options specific to the [Socket] section of service | |
| 100 | units are the following:</para> | |
| 101 | ||
| 102 | <variablelist> | |
| 103 | <varlistentry> | |
| 104 | <term><varname>ListenStream=</varname></term> | |
| 105 | <term><varname>ListenDatagram=</varname></term> | |
| 106 | <term><varname>ListenSequentialPacket=</varname></term> | |
| 107 | <listitem><para>Specifies an address | |
| 108 | to listen on for a stream | |
| 109 | (SOCK_STREAM), datagram (SOCK_DGRAM) | |
| 110 | resp. sequential packet | |
| 111 | (SOCK_SEQPACKET) socket. The address | |
| 112 | can be written in various formats:</para> | |
| 113 | ||
| 114 | <para>If the address starts with a | |
| 115 | slash (/), it is read as file system | |
| 116 | socket in the AF_UNIX socket | |
| 117 | family.</para> | |
| 118 | ||
| 119 | <para>If the address starts with an | |
| 120 | ampersand (@) it is read as abstract | |
| 121 | namespace socket in the AF_UNIX | |
| 122 | family. The @ is replaced with a NUL | |
| 123 | character before binding. For details | |
| 124 | see | |
| 125 | <citerefentry><refentrytitle>unix</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> | |
| 126 | ||
| 127 | <para>If the address string is a | |
| 128 | single number it is read as port | |
| 129 | number to listen on for both IPv4 and | |
| 130 | IPv6.</para> | |
| 131 | ||
| 132 | <para>If the address string is a | |
| 133 | string in the format v.w.x.y:z it is | |
| 134 | read as IPv4 specifier for listening | |
| 135 | on an address v.w.x.y on a port | |
| 136 | z.</para> | |
| 137 | ||
| 138 | <para>If the address string is a | |
| 139 | string in the format [x]:y it is read | |
| 140 | as IPv6 address x on a port y.</para> | |
| 141 | ||
| 142 | <para>Note that SOCK_SEQPACKET | |
| 143 | (i.e. <varname>ListenSequentialPacket=</varname>) | |
| 144 | is only available for AF_UNIX | |
| 145 | sockets. SOCK_STREAM | |
| 146 | (i.e. <varname>ListenStream=</varname>) | |
| 147 | when used for IP sockets refers to TCP | |
| 148 | sockets, SOCK_DGRAM | |
| 149 | (i.e. <varname>ListenDatagram=</varname>) | |
| 150 | to UDP.</para> | |
| 151 | ||
| 152 | <para>These options may be specified | |
| 153 | more than once in which case incoming | |
| 154 | traffic on any of the sockets will trigger | |
| 155 | service activation, and all listed | |
| 156 | sockets will be passed to the service, | |
| 157 | regardless whether there is incoming | |
| 158 | traffic on them or not.</para> | |
| 159 | ||
| 160 | <para>If an IP address is used here it | |
| 161 | is often desirable to listen on it | |
| 162 | before the interface it is configured | |
| 163 | on is up and running, and even | |
| 164 | regardless whether it will be up and | |
| 165 | running ever at all. To deal with this it is | |
| 166 | recommended to set the | |
| 167 | <varname>FreeBind=</varname> option | |
| 168 | described below.</para></listitem> | |
| 169 | </varlistentry> | |
| 170 | ||
| 171 | <varlistentry> | |
| 172 | <term><varname>ListenFIFO=</varname></term> | |
| 173 | <listitem><para>Specifies a file | |
| 174 | system FIFO to listen on. This expects | |
| 175 | an absolute file system path as | |
| 176 | argument. Behaviour otherwise is very | |
| 177 | similar to the | |
| 178 | <varname>ListenDatagram=</varname> | |
| 179 | directive above.</para></listitem> | |
| 180 | </varlistentry> | |
| 181 | ||
| 182 | <varlistentry> | |
| 183 | <term><varname>BindIPv6Only=</varname></term> | |
| 184 | <listitem><para>Takes a one of | |
| 185 | <option>default</option>, | |
| 186 | <option>both</option> or | |
| 187 | <option>ipv6-only</option>. Controls | |
| 188 | the IPV6_V6ONLY socket option (see | |
| 189 | <citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 190 | for details). If | |
| 191 | <option>both</option>, IPv6 sockets | |
| 192 | bound will be accessible via both IPv4 | |
| 193 | and IPv6. If | |
| 194 | <option>ipv6-only</option>, they will | |
| 195 | be accessible via IPv6 only. If | |
| 196 | <option>default</option> (which is the | |
| 197 | default, surprise!) the system wide | |
| 198 | default setting is used, as controlled | |
| 199 | by | |
| 200 | <filename>/proc/sys/net/ipv6/bindv6only</filename>.</para> | |
| 201 | </listitem> | |
| 202 | </varlistentry> | |
| 203 | ||
| 204 | <varlistentry> | |
| 205 | <term><varname>Backlog=</varname></term> | |
| 206 | <listitem><para>Takes an unsigned | |
| 207 | integer argument. Specifies the number | |
| 208 | of connections to queue that have not | |
| 209 | been accepted yet. This setting | |
| 210 | matters only for stream and sequential | |
| 211 | packet sockets. See | |
| 212 | <citerefentry><refentrytitle>listen</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
| 213 | for details. Defaults to SOMAXCONN | |
| 214 | (128).</para></listitem> | |
| 215 | </varlistentry> | |
| 216 | ||
| 217 | <varlistentry> | |
| 218 | <term><varname>BindToDevice=</varname></term> | |
| 219 | <listitem><para>Specifies a network | |
| 220 | interface name to bind this socket | |
| 221 | to. If set traffic will only be | |
| 222 | accepted from the specified network | |
| 223 | interfaces. This controls the | |
| 224 | SO_BINDTODEVICE socket option (see | |
| 225 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 226 | for details). If this option is used | |
| 227 | an automatic dependency from this | |
| 228 | socket unit on the network interface | |
| 229 | device unit | |
| 230 | (<citerefentry><refentrytitle>systemd.device</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
| 231 | is created.</para></listitem> | |
| 232 | </varlistentry> | |
| 233 | ||
| 234 | <varlistentry> | |
| 235 | <term><varname>DirectoryMode=</varname></term> | |
| 236 | <listitem><para>If listening on a file | |
| 237 | system socket of FIFO the parent | |
| 238 | directories are automatically created | |
| 239 | if needed. This option specifies the | |
| 240 | file system access mode used when | |
| 241 | creating these directories. Defaults | |
| 242 | to 0755.</para></listitem> | |
| 243 | </varlistentry> | |
| 244 | ||
| 245 | <varlistentry> | |
| 246 | <term><varname>SocketMode=</varname></term> | |
| 247 | <listitem><para>If listening on a file | |
| 248 | system socket of FIFO this option | |
| 249 | specifies the file system access mode | |
| 250 | used when creating the file | |
| 251 | node. Defaults to | |
| 252 | 0666.</para></listitem> | |
| 253 | </varlistentry> | |
| 254 | ||
| 255 | <varlistentry> | |
| 256 | <term><varname>Accept=</varname></term> | |
| 257 | <listitem><para>Takes a boolean | |
| 258 | argument. If true a service instance | |
| 259 | is spawned for each incoming | |
| 260 | connection and only the connection | |
| 261 | socket is passed to it. If false all | |
| 262 | listening sockets themselves are | |
| 263 | passed to the started service unit, | |
| 264 | and only one service unit is spawned | |
| 265 | for all connections (also see | |
| 266 | above). This value is ignored for | |
| 267 | datagram sockets and FIFOs where | |
| 268 | unconditionally a single service unit | |
| 269 | handles all incoming traffic. Defaults | |
| 270 | to <option>false</option>. For | |
| 271 | performance reasons it is recommended | |
| 272 | to write new daemons only in a way | |
| 273 | that is suitable for | |
| 274 | <option>Accept=false</option>. This | |
| 275 | option is mostly useful to allow | |
| 276 | daemons designed for usage with | |
| 277 | <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
| 278 | to work unmodified with system socket | |
| 279 | activation.</para></listitem> | |
| 280 | </varlistentry> | |
| 281 | ||
| 282 | <varlistentry> | |
| 283 | <term><varname>MaxConnections=</varname></term> | |
| 284 | <listitem><para>The maximum number of | |
| 285 | connections to simultaneously run | |
| 286 | services instances for, when | |
| 287 | <option>Accept=true</option> is | |
| 288 | set. If more concurrent connections | |
| 289 | are coming in they will be refused, | |
| 290 | until at least one existing connection | |
| 291 | is terminated. This setting has no | |
| 292 | effect for sockets configured with | |
| 293 | <option>Accept=no</option> or datagram | |
| 294 | sockets. Defaults to | |
| 295 | 64.</para></listitem> | |
| 296 | </varlistentry> | |
| 297 | ||
| 298 | <varlistentry> | |
| 299 | <term><varname>KeepAlive=</varname></term> | |
| 300 | <listitem><para>Takes a boolean | |
| 301 | argument. If true, the TCP/IP stack | |
| 302 | will send a keep alive message after | |
| 303 | 2h (depending on the configuration of | |
| 304 | <filename>/proc/sys/net/ipv4/tcp_keepalive_time</filename>) | |
| 305 | for all TCP streams accepted on this | |
| 306 | socket. This controls the SO_KEEPALIVE | |
| 307 | socket option (see | |
| 308 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 309 | and the <ulink | |
| 310 | url="http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/">TCP | |
| 311 | Keepalive HOWTO</ulink> for details.) | |
| 312 | Defaults to | |
| 313 | <option>false</option>.</para></listitem> | |
| 314 | </varlistentry> | |
| 315 | ||
| 316 | <varlistentry> | |
| 317 | <term><varname>Priority=</varname></term> | |
| 318 | <listitem><para>Takes an integer | |
| 319 | argument controlling the priority for | |
| 320 | all traffic sent from this | |
| 321 | socket. This controls the SO_PRIORITY | |
| 322 | socket option (see | |
| 323 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 324 | for details.).</para></listitem> | |
| 325 | </varlistentry> | |
| 326 | ||
| 327 | <varlistentry> | |
| 328 | <term><varname>ReceiveBuffer=</varname></term> | |
| 329 | <term><varname>SendBuffer=</varname></term> | |
| 330 | <listitem><para>Takes an integer | |
| 331 | argument controlling the receive | |
| 332 | resp. send buffer sizes of this | |
| 333 | socket. This controls the SO_RCVBUF | |
| 334 | resp. SO_SNDBUF socket options (see | |
| 335 | <citerefentry><refentrytitle>socket</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 336 | for details.).</para></listitem> | |
| 337 | </varlistentry> | |
| 338 | ||
| 339 | <varlistentry> | |
| 340 | <term><varname>IPTOS=</varname></term> | |
| 341 | <listitem><para>Takes an integer | |
| 342 | argument controlling the IP | |
| 343 | Type-Of-Service field for packets | |
| 344 | generated from this socket. This | |
| 345 | controls the IP_TOS socket option (see | |
| 346 | <citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 347 | for details.). Either a numeric string | |
| 348 | or one of <option>low-delay</option>, | |
| 349 | <option>throughput</option>, | |
| 350 | <option>reliability</option> or | |
| 351 | <option>low-cost</option> may be | |
| 352 | specified.</para></listitem> | |
| 353 | </varlistentry> | |
| 354 | ||
| 355 | <varlistentry> | |
| 356 | <term><varname>IPTTL=</varname></term> | |
| 357 | <listitem><para>Takes an integer | |
| 358 | argument controlling the IPv4 | |
| 359 | Time-To-Live/IPv6 Hop-Count field for | |
| 360 | packets generated from this | |
| 361 | socket. This sets the | |
| 362 | IP_TTL/IPV6_UNICAST_HOPS socket | |
| 363 | options (see | |
| 364 | <citerefentry><refentrytitle>ip</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 365 | and | |
| 366 | <citerefentry><refentrytitle>ipv6</refentrytitle><manvolnum>7</manvolnum></citerefentry> | |
| 367 | for details.)</para></listitem> | |
| 368 | </varlistentry> | |
| 369 | ||
| 370 | <varlistentry> | |
| 371 | <term><varname>Mark=</varname></term> | |
| 372 | <listitem><para>Takes an integer | |
| 373 | value. Controls the firewall mark of | |
| 374 | packets generated by this socket. This | |
| 375 | can be used in the firewall logic to | |
| 376 | filter packets from this socket. This | |
| 377 | sets the SO_MARK socket option. See | |
| 378 | <citerefentry><refentrytitle>iptables</refentrytitle><manvolnum>8</manvolnum></citerefentry> | |
| 379 | for details.</para></listitem> | |
| 380 | </varlistentry> | |
| 381 | ||
| 382 | <varlistentry> | |
| 383 | <term><varname>PipeSize=</varname></term> | |
| 384 | <listitem><para>Takes an integer | |
| 385 | value. Controls the pipe buffer size | |
| 386 | of FIFOs configured in this socket | |
| 387 | unit. See | |
| 388 | <citerefentry><refentrytitle>fcntl</refentrytitle><manvolnum>2</manvolnum></citerefentry> | |
| 389 | for details.</para></listitem> | |
| 390 | </varlistentry> | |
| 391 | ||
| 392 | <varlistentry> | |
| 393 | <term><varname>FreeBind=</varname></term> | |
| 394 | <listitem><para>Takes a boolean | |
| 395 | value. Controls whether the socket can | |
| 396 | be bound to non-local IP | |
| 397 | addresses. This is useful to configure | |
| 398 | sockets listening on specific IP | |
| 399 | addresses before those IP addresses | |
| 400 | are successfully configured on a | |
| 401 | network interface. This sets the | |
| 402 | IP_FREEBIND socket option. For | |
| 403 | robustness reasons it is recommended | |
| 404 | to use this option whenever you bind a | |
| 405 | socket to a specific IP | |
| 406 | address. Defaults to <option>false</option>.</para></listitem> | |
| 407 | </varlistentry> | |
| 408 | ||
| 409 | <!-- | |
| 410 | { "TimeoutSec", config_parse_usec, &u->socket.timeout_usec, "Socket" }, | |
| 411 | { "KillMode", config_parse_kill_mode, &u->socket.kill_mode, "Socket" }, | |
| 412 | --> | |
| 413 | <varlistentry> | |
| 414 | <term><varname>ExecStartPre=</varname></term> | |
| 415 | <term><varname>ExecStartPost=</varname></term> | |
| 416 | <listitem><para>Takes a command line | |
| 417 | that is executed before (resp. after) | |
| 418 | the listening sockets/FIFOs are created and | |
| 419 | bound. The first token of the command | |
| 420 | line must be an absolute file name, | |
| 421 | then followed by arguments for the | |
| 422 | process. If specified more than once, | |
| 423 | all commands are executed one after | |
| 424 | the other, serially. Use of these | |
| 425 | settings is optional.</para></listitem> | |
| 426 | </varlistentry> | |
| 427 | ||
| 428 | <varlistentry> | |
| 429 | <term><varname>ExecStopPre=</varname></term> | |
| 430 | <term><varname>ExecStopPost=</varname></term> | |
| 431 | <listitem><para>Additional commands | |
| 432 | that are executed before (resp. after) | |
| 433 | the listening sockets/FIFOs are closed | |
| 434 | and removed. If specified more than | |
| 435 | once, all commands are executed one | |
| 436 | after the other, serially. Use of | |
| 437 | these settings is | |
| 438 | optional.</para></listitem> | |
| 439 | </varlistentry> | |
| 440 | ||
| 441 | ||
| 442 | <varlistentry> | |
| 443 | <term><varname>TimeoutSec=</varname></term> | |
| 444 | <listitem><para>Configures the time to | |
| 445 | wait for the commands specified in | |
| 446 | <varname>ExecStartPre=</varname>, | |
| 447 | <varname>ExecStartPost=</varname>, | |
| 448 | <varname>ExecStopPre=</varname> and | |
| 449 | <varname>ExecStopPost=</varname> to | |
| 450 | finish. If a comand does not exit | |
| 451 | within the configured time the socket | |
| 452 | will be considered failed and be shut | |
| 453 | down again. All commands still running | |
| 454 | will be terminated forcibly via | |
| 455 | SIGTERM, and after another delay of | |
| 456 | this time with SIGKILL. (See | |
| 457 | <option>KilleMode=</option> below.) | |
| 458 | Takes a unit-less value in seconds, or | |
| 459 | a time span value such as "5min | |
| 460 | 20s". Pass 0 to disable the timeout | |
| 461 | logic. Defaults to | |
| 462 | 60s.</para></listitem> | |
| 463 | </varlistentry> | |
| 464 | ||
| 465 | ||
| 466 | <varlistentry> | |
| 467 | <term><varname>KillMode=</varname></term> | |
| 468 | <listitem><para>Specifies how | |
| 469 | processes of this service shall be | |
| 470 | killed. One of | |
| 471 | <option>control-group</option>, | |
| 472 | <option>process-group</option>, | |
| 473 | <option>process</option>, | |
| 474 | <option>none</option>.</para> | |
| 475 | ||
| 476 | <para>This option is mostly equivalent | |
| 477 | to the <option>KillMode=</option> | |
| 478 | option of service files. See | |
| 479 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
| 480 | for details.</para></listitem> | |
| 481 | </varlistentry> | |
| 482 | ||
| 483 | ||
| 484 | </variablelist> | |
| 485 | </refsect1> | |
| 486 | ||
| 487 | <refsect1> | |
| 488 | <title>See Also</title> | |
| 489 | <para> | |
| 490 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
| 491 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>, | |
| 492 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
| 493 | <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
| 494 | <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> | |
| 495 | </para> | |
| 496 | </refsect1> | |
| 497 | ||
| 498 | </refentry> |