man/systemd.exec.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 Lesser General Public License as published by
  13   the Free Software Foundation; either version 2.1 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   Lesser General Public License for more details.
  20
  21   You should have received a copy of the GNU Lesser General Public License
  22   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  23 -->
  24
  25 <refentry id="systemd.exec">
  26         <refentryinfo>
  27                 <title>systemd.exec</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.exec</refentrytitle>
  42                 <manvolnum>5</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd.exec</refname>
  47                 <refpurpose>Execution environment configuration</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename>systemd.service</filename>,
  52                 <filename>systemd.socket</filename>,
  53                 <filename>systemd.mount</filename>,
  54                 <filename>systemd.swap</filename></para>
  55         </refsynopsisdiv>
  56
  57         <refsect1>
  58                 <title>Description</title>
  59
  60                 <para>Unit configuration files for services, sockets,
  61                 mount points and swap devices share a subset of
  62                 configuration options which define the execution
  63                 environment of spawned processes.</para>
  64
  65                 <para>This man page lists the configuration options
  66                 shared by these four unit types. See
  67                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  68                 for the common options of all unit configuration
  69                 files, and
  70                 <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  71                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  72                 <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  73                 and
  74                 <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  75                 for more information on the specific unit
  76                 configuration files. The execution specific
  77                 configuration options are configured in the [Service],
  78                 [Socket], [Mount], or [Swap] sections, depending on the unit
  79                 type.</para>
  80         </refsect1>
  81
  82         <refsect1>
  83                 <title>Options</title>
  84
  85                 <variablelist>
  86
  87                         <varlistentry>
  88                                 <term><varname>WorkingDirectory=</varname></term>
  89
  90                                 <listitem><para>Takes an absolute
  91                                 directory path. Sets the working
  92                                 directory for executed processes. If
  93                                 not set defaults to the root directory
  94                                 when systemd is running as a system
  95                                 instance and the respective user's
  96                                 home directory if run as
  97                                 user.</para></listitem>
  98                         </varlistentry>
  99
 100                         <varlistentry>
 101                                 <term><varname>RootDirectory=</varname></term>
 102
 103                                 <listitem><para>Takes an absolute
 104                                 directory path. Sets the root
 105                                 directory for executed processes, with
 106                                 the
 107                                 <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 108                                 system call. If this is used it must
 109                                 be ensured that the process and all
 110                                 its auxiliary files are available in
 111                                 the <function>chroot()</function>
 112                                 jail.</para></listitem>
 113                         </varlistentry>
 114
 115                         <varlistentry>
 116                                 <term><varname>User=</varname></term>
 117                                 <term><varname>Group=</varname></term>
 118
 119                                 <listitem><para>Sets the Unix user
 120                                 or group that the processes are executed
 121                                 as, respectively. Takes a single user or group
 122                                 name or ID as argument. If no group is
 123                                 set, the default group of the user is
 124                                 chosen.</para></listitem>
 125                         </varlistentry>
 126
 127                         <varlistentry>
 128                                 <term><varname>SupplementaryGroups=</varname></term>
 129
 130                                 <listitem><para>Sets the supplementary
 131                                 Unix groups the processes are executed
 132                                 as. This takes a space separated list
 133                                 of group names or IDs. This option may
 134                                 be specified more than once in which
 135                                 case all listed groups are set as
 136                                 supplementary groups. This option does
 137                                 not override but extends the list of
 138                                 supplementary groups configured in the
 139                                 system group database for the
 140                                 user.</para></listitem>
 141                         </varlistentry>
 142
 143                         <varlistentry>
 144                                 <term><varname>Nice=</varname></term>
 145
 146                                 <listitem><para>Sets the default nice
 147                                 level (scheduling priority) for
 148                                 executed processes. Takes an integer
 149                                 between -20 (highest priority) and 19
 150                                 (lowest priority). See
 151                                 <citerefentry><refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 152                                 for details.</para></listitem>
 153                         </varlistentry>
 154
 155                         <varlistentry>
 156                                 <term><varname>OOMScoreAdjust=</varname></term>
 157
 158                                 <listitem><para>Sets the adjustment
 159                                 level for the Out-Of-Memory killer for
 160                                 executed processes. Takes an integer
 161                                 between -1000 (to disable OOM killing
 162                                 for this process) and 1000 (to make
 163                                 killing of this process under memory
 164                                 pressure very likely). See <ulink
 165                                 url="http://www.kernel.org/doc/Documentation/filesystems/proc.txt">proc.txt</ulink>
 166                                 for details.</para></listitem>
 167                         </varlistentry>
 168
 169                         <varlistentry>
 170                                 <term><varname>IOSchedulingClass=</varname></term>
 171
 172                                 <listitem><para>Sets the IO scheduling
 173                                 class for executed processes. Takes an
 174                                 integer between 0 and 3 or one of the
 175                                 strings <option>none</option>,
 176                                 <option>realtime</option>,
 177                                 <option>best-effort</option> or
 178                                 <option>idle</option>. See
 179                                 <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 180                                 for details.</para></listitem>
 181                         </varlistentry>
 182
 183                         <varlistentry>
 184                                 <term><varname>IOSchedulingPriority=</varname></term>
 185
 186                                 <listitem><para>Sets the IO scheduling
 187                                 priority for executed processes. Takes
 188                                 an integer between 0 (highest
 189                                 priority) and 7 (lowest priority). The
 190                                 available priorities depend on the
 191                                 selected IO scheduling class (see
 192                                 above). See
 193                                 <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 194                                 for details.</para></listitem>
 195                         </varlistentry>
 196
 197                         <varlistentry>
 198                                 <term><varname>CPUSchedulingPolicy=</varname></term>
 199
 200                                 <listitem><para>Sets the CPU
 201                                 scheduling policy for executed
 202                                 processes. Takes one of
 203                                 <option>other</option>,
 204                                 <option>batch</option>,
 205                                 <option>idle</option>,
 206                                 <option>fifo</option> or
 207                                 <option>rr</option>. See
 208                                 <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 209                                 for details.</para></listitem>
 210                         </varlistentry>
 211
 212                         <varlistentry>
 213                                 <term><varname>CPUSchedulingPriority=</varname></term>
 214
 215                                 <listitem><para>Sets the CPU
 216                                 scheduling priority for executed
 217                                 processes. Takes an integer between 1
 218                                 (lowest priority) and 99 (highest
 219                                 priority). The available priority
 220                                 range depends on the selected CPU
 221                                 scheduling policy (see above). See
 222                                 <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 223                                 for details.</para></listitem>
 224                         </varlistentry>
 225
 226                         <varlistentry>
 227                                 <term><varname>CPUSchedulingResetOnFork=</varname></term>
 228
 229                                 <listitem><para>Takes a boolean
 230                                 argument. If true elevated CPU
 231                                 scheduling priorities and policies
 232                                 will be reset when the executed
 233                                 processes fork, and can hence not leak
 234                                 into child processes. See
 235                                 <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 236                                 for details. Defaults to false.</para></listitem>
 237                         </varlistentry>
 238
 239                         <varlistentry>
 240                                 <term><varname>CPUAffinity=</varname></term>
 241
 242                                 <listitem><para>Controls the CPU
 243                                 affinity of the executed
 244                                 processes. Takes a space-separated
 245                                 list of CPU indexes. See
 246                                 <citerefentry><refentrytitle>sched_setaffinity</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 247                                 for details.</para></listitem>
 248                         </varlistentry>
 249
 250                         <varlistentry>
 251                                 <term><varname>UMask=</varname></term>
 252
 253                                 <listitem><para>Controls the file mode
 254                                 creation mask. Takes an access mode in
 255                                 octal notation. See
 256                                 <citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 257                                 for details. Defaults to
 258                                 0022.</para></listitem>
 259                         </varlistentry>
 260
 261                         <varlistentry>
 262                                 <term><varname>Environment=</varname></term>
 263
 264                                 <listitem><para>Sets environment
 265                                 variables for executed
 266                                 processes. Takes a space-separated
 267                                 list of variable assignments. This
 268                                 option may be specified more than once
 269                                 in which case all listed variables
 270                                 will be set. If the same variable is
 271                                 set twice the later setting will
 272                                 override the earlier setting. See
 273                                 <citerefentry><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 274                                 for details.</para></listitem>
 275                         </varlistentry>
 276                         <varlistentry>
 277                                 <term><varname>EnvironmentFile=</varname></term>
 278                                 <listitem><para>Similar to
 279                                 <varname>Environment=</varname> but
 280                                 reads the environment variables from a
 281                                 text file. The text file should
 282                                 contain new-line separated variable
 283                                 assignments. Empty lines and lines
 284                                 starting with ; or # will be ignored,
 285                                 which may be used for commenting. The
 286                                 parser strips leading and
 287                                 trailing whitespace from the values
 288                                 of assignments, unless you use
 289                                 double quotes (").
 290                                 The
 291                                 argument passed should be an absolute
 292                                 file name, optionally prefixed with
 293                                 "-", which indicates that if the file
 294                                 does not exist it won't be read and no
 295                                 error or warning message is
 296                                 logged. The files listed with this
 297                                 directive will be read shortly before
 298                                 the process is executed. Settings from
 299                                 these files override settings made
 300                                 with
 301                                 <varname>Environment=</varname>. If
 302                                 the same variable is set twice from
 303                                 these files the files will be read in
 304                                 the order they are specified and the
 305                                 later setting will override the
 306                                 earlier setting. </para></listitem>
 307                         </varlistentry>
 308
 309                         <varlistentry>
 310                                 <term><varname>StandardInput=</varname></term>
 311                                 <listitem><para>Controls where file
 312                                 descriptor 0 (STDIN) of the executed
 313                                 processes is connected to. Takes one
 314                                 of <option>null</option>,
 315                                 <option>tty</option>,
 316                                 <option>tty-force</option>,
 317                                 <option>tty-fail</option> or
 318                                 <option>socket</option>. If
 319                                 <option>null</option> is selected
 320                                 standard input will be connected to
 321                                 <filename>/dev/null</filename>,
 322                                 i.e. all read attempts by the process
 323                                 will result in immediate EOF. If
 324                                 <option>tty</option> is selected
 325                                 standard input is connected to a TTY
 326                                 (as configured by
 327                                 <varname>TTYPath=</varname>, see
 328                                 below) and the executed process
 329                                 becomes the controlling process of the
 330                                 terminal. If the terminal is already
 331                                 being controlled by another process the
 332                                 executed process waits until the current
 333                                 controlling process releases the
 334                                 terminal.
 335                                 <option>tty-force</option>
 336                                 is similar to <option>tty</option>,
 337                                 but the executed process is forcefully
 338                                 and immediately made the controlling
 339                                 process of the terminal, potentially
 340                                 removing previous controlling
 341                                 processes from the
 342                                 terminal. <option>tty-fail</option> is
 343                                 similar to <option>tty</option> but if
 344                                 the terminal already has a controlling
 345                                 process start-up of the executed
 346                                 process fails.  The
 347                                 <option>socket</option> option is only
 348                                 valid in socket-activated services,
 349                                 and only when the socket configuration
 350                                 file (see
 351                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 352                                 for details) specifies a single socket
 353                                 only. If this option is set standard
 354                                 input will be connected to the socket
 355                                 the service was activated from, which
 356                                 is primarily useful for compatibility
 357                                 with daemons designed for use with the
 358                                 traditional
 359                                 <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 360                                 daemon. This setting defaults to
 361                                 <option>null</option>.</para></listitem>
 362                         </varlistentry>
 363                         <varlistentry>
 364                                 <term><varname>StandardOutput=</varname></term>
 365                                 <listitem><para>Controls where file
 366                                 descriptor 1 (STDOUT) of the executed
 367                                 processes is connected to. Takes one
 368                                 of <option>inherit</option>,
 369                                 <option>null</option>,
 370                                 <option>tty</option>,
 371                                 <option>syslog</option>,
 372                                 <option>kmsg</option>,
 373                                 <option>journal</option>,
 374                                 <option>syslog+console</option>,
 375                                 <option>kmsg+console</option>,
 376                                 <option>journal+console</option> or
 377                                 <option>socket</option>. If set to
 378                                 <option>inherit</option> the file
 379                                 descriptor of standard input is
 380                                 duplicated for standard output. If set
 381                                 to <option>null</option> standard
 382                                 output will be connected to
 383                                 <filename>/dev/null</filename>,
 384                                 i.e. everything written to it will be
 385                                 lost. If set to <option>tty</option>
 386                                 standard output will be connected to a
 387                                 tty (as configured via
 388                                 <varname>TTYPath=</varname>, see
 389                                 below). If the TTY is used for output
 390                                 only the executed process will not
 391                                 become the controlling process of the
 392                                 terminal, and will not fail or wait
 393                                 for other processes to release the
 394                                 terminal. <option>syslog</option>
 395                                 connects standard output to the
 396                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 397                                 system syslog
 398                                 service. <option>kmsg</option>
 399                                 connects it with the kernel log buffer
 400                                 which is accessible via
 401                                 <citerefentry><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>. <option>journal</option>
 402                                 connects it with the journal which is
 403                                 accessible via
 404                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 405                                 (Note that everything that is written
 406                                 to syslog or kmsg is implicitly stored
 407                                 in the journal as well, those options
 408                                 are hence supersets of this
 409                                 one). <option>syslog+console</option>,
 410                                 <option>journal+console</option> and
 411                                 <option>kmsg+console</option> work
 412                                 similarly but copy the output to the
 413                                 system console as
 414                                 well. <option>socket</option> connects
 415                                 standard output to a socket from
 416                                 socket activation, semantics are
 417                                 similar to the respective option of
 418                                 <varname>StandardInput=</varname>.
 419                                 This setting defaults to the value set
 420                                 with
 421                                 <option>DefaultStandardOutput=</option>
 422                                 in
 423                                 <citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 424                                 which defaults to
 425                                 <option>journal</option>.</para></listitem>
 426                         </varlistentry>
 427                         <varlistentry>
 428                                 <term><varname>StandardError=</varname></term>
 429                                 <listitem><para>Controls where file
 430                                 descriptor 2 (STDERR) of the executed
 431                                 processes is connected to. The
 432                                 available options are identical to
 433                                 those of
 434                                 <varname>StandardOutput=</varname>,
 435                                 with one exception: if set to
 436                                 <option>inherit</option> the file
 437                                 descriptor used for standard output is
 438                                 duplicated for standard error. This
 439                                 setting defaults to the value set with
 440                                 <option>DefaultStandardError=</option>
 441                                 in
 442                                 <citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 443                                 which defaults to
 444                                 <option>inherit</option>.</para></listitem>
 445                         </varlistentry>
 446                         <varlistentry>
 447                                 <term><varname>TTYPath=</varname></term>
 448                                 <listitem><para>Sets the terminal
 449                                 device node to use if standard input,
 450                                 output or stderr are connected to a
 451                                 TTY (see above). Defaults to
 452                                 <filename>/dev/console</filename>.</para></listitem>
 453                         </varlistentry>
 454                         <varlistentry>
 455                                 <term><varname>TTYReset=</varname></term>
 456                                 <listitem><para>Reset the terminal
 457                                 device specified with
 458                                 <varname>TTYPath=</varname> before and
 459                                 after execution. Defaults to
 460                                 <literal>no</literal>.</para></listitem>
 461                         </varlistentry>
 462                         <varlistentry>
 463                                 <term><varname>TTYVHangup=</varname></term>
 464                                 <listitem><para>Disconnect all clients
 465                                 which have opened the terminal device
 466                                 specified with
 467                                 <varname>TTYPath=</varname>
 468                                 before and after execution. Defaults
 469                                 to
 470                                 <literal>no</literal>.</para></listitem>
 471                         </varlistentry>
 472                         <varlistentry>
 473                                 <term><varname>TTYVTDisallocate=</varname></term>
 474                                 <listitem><para>If the terminal
 475                                 device specified with
 476                                 <varname>TTYPath=</varname> is a
 477                                 virtual console terminal try to
 478                                 deallocate the TTY before and after
 479                                 execution. This ensures that the
 480                                 screen and scrollback buffer is
 481                                 cleared. Defaults to
 482                                 <literal>no</literal>.</para></listitem>
 483                         </varlistentry>
 484                         <varlistentry>
 485                                 <term><varname>SyslogIdentifier=</varname></term>
 486                                 <listitem><para>Sets the process name
 487                                 to prefix log lines sent to syslog or
 488                                 the kernel log buffer with. If not set
 489                                 defaults to the process name of the
 490                                 executed process. This option is only
 491                                 useful when
 492                                 <varname>StandardOutput=</varname> or
 493                                 <varname>StandardError=</varname> are
 494                                 set to <option>syslog</option> or
 495                                 <option>kmsg</option>.</para></listitem>
 496                         </varlistentry>
 497                         <varlistentry>
 498                                 <term><varname>SyslogFacility=</varname></term>
 499                                 <listitem><para>Sets the syslog
 500                                 facility to use when logging to
 501                                 syslog. One of <option>kern</option>,
 502                                 <option>user</option>,
 503                                 <option>mail</option>,
 504                                 <option>daemon</option>,
 505                                 <option>auth</option>,
 506                                 <option>syslog</option>,
 507                                 <option>lpr</option>,
 508                                 <option>news</option>,
 509                                 <option>uucp</option>,
 510                                 <option>cron</option>,
 511                                 <option>authpriv</option>,
 512                                 <option>ftp</option>,
 513                                 <option>local0</option>,
 514                                 <option>local1</option>,
 515                                 <option>local2</option>,
 516                                 <option>local3</option>,
 517                                 <option>local4</option>,
 518                                 <option>local5</option>,
 519                                 <option>local6</option> or
 520                                 <option>local7</option>. See
 521                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 522                                 for details. This option is only
 523                                 useful when
 524                                 <varname>StandardOutput=</varname> or
 525                                 <varname>StandardError=</varname> are
 526                                 set to <option>syslog</option>.
 527                                 Defaults to
 528                                 <option>daemon</option>.</para></listitem>
 529                         </varlistentry>
 530                         <varlistentry>
 531                                 <term><varname>SyslogLevel=</varname></term>
 532                                 <listitem><para>Default syslog level
 533                                 to use when logging to syslog or the
 534                                 kernel log buffer. One of
 535                                 <option>emerg</option>,
 536                                 <option>alert</option>,
 537                                 <option>crit</option>,
 538                                 <option>err</option>,
 539                                 <option>warning</option>,
 540                                 <option>notice</option>,
 541                                 <option>info</option>,
 542                                 <option>debug</option>. See
 543                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 544                                 for details. This option is only
 545                                 useful when
 546                                 <varname>StandardOutput=</varname> or
 547                                 <varname>StandardError=</varname> are
 548                                 set to <option>syslog</option> or
 549                                 <option>kmsg</option>. Note that
 550                                 individual lines output by the daemon
 551                                 might be prefixed with a different log
 552                                 level which can be used to override
 553                                 the default log level specified
 554                                 here. The interpretation of these
 555                                 prefixes may be disabled with
 556                                 <varname>SyslogLevelPrefix=</varname>,
 557                                 see below. For details see
 558                                 <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 559
 560                                 Defaults to
 561                                 <option>info</option>.</para></listitem>
 562                         </varlistentry>
 563
 564                         <varlistentry>
 565                                 <term><varname>SyslogLevelPrefix=</varname></term>
 566                                 <listitem><para>Takes a boolean
 567                                 argument. If true and
 568                                 <varname>StandardOutput=</varname> or
 569                                 <varname>StandardError=</varname> are
 570                                 set to <option>syslog</option>,
 571                                 <option>kmsg</option> or
 572                                 <option>journal</option>, log lines
 573                                 written by the executed process that
 574                                 are prefixed with a log level will be
 575                                 passed on to syslog with this log
 576                                 level set but the prefix removed. If
 577                                 set to false, the interpretation of
 578                                 these prefixes is disabled and the
 579                                 logged lines are passed on as-is. For
 580                                 details about this prefixing see
 581                                 <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 582                                 Defaults to true.</para></listitem>
 583                         </varlistentry>
 584
 585                         <varlistentry>
 586                                 <term><varname>TimerSlackNSec=</varname></term>
 587                                 <listitem><para>Sets the timer slack
 588                                 in nanoseconds for the executed
 589                                 processes. The timer slack controls
 590                                 the accuracy of wake-ups triggered by
 591                                 timers. See
 592                                 <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 593                                 for more information. Note that in
 594                                 contrast to most other time span
 595                                 definitions this parameter takes an
 596                                 integer value in nano-seconds if no
 597                                 unit is specified. The usual time
 598                                 units are understood
 599                                 too.</para></listitem>
 600                         </varlistentry>
 601
 602                         <varlistentry>
 603                                 <term><varname>LimitCPU=</varname></term>
 604                                 <term><varname>LimitFSIZE=</varname></term>
 605                                 <term><varname>LimitDATA=</varname></term>
 606                                 <term><varname>LimitSTACK=</varname></term>
 607                                 <term><varname>LimitCORE=</varname></term>
 608                                 <term><varname>LimitRSS=</varname></term>
 609                                 <term><varname>LimitNOFILE=</varname></term>
 610                                 <term><varname>LimitAS=</varname></term>
 611                                 <term><varname>LimitNPROC=</varname></term>
 612                                 <term><varname>LimitMEMLOCK=</varname></term>
 613                                 <term><varname>LimitLOCKS=</varname></term>
 614                                 <term><varname>LimitSIGPENDING=</varname></term>
 615                                 <term><varname>LimitMSGQUEUE=</varname></term>
 616                                 <term><varname>LimitNICE=</varname></term>
 617                                 <term><varname>LimitRTPRIO=</varname></term>
 618                                 <term><varname>LimitRTTIME=</varname></term>
 619                                 <listitem><para>These settings control
 620                                 various resource limits for executed
 621                                 processes. See
 622                                 <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 623                                 for details. Use the string
 624                                 <varname>infinity</varname> to
 625                                 configure no limit on a specific
 626                                 resource.</para></listitem>
 627                         </varlistentry>
 628
 629                         <varlistentry>
 630                                 <term><varname>PAMName=</varname></term>
 631                                 <listitem><para>Sets the PAM service
 632                                 name to set up a session as. If set
 633                                 the executed process will be
 634                                 registered as a PAM session under the
 635                                 specified service name. This is only
 636                                 useful in conjunction with the
 637                                 <varname>User=</varname> setting. If
 638                                 not set no PAM session will be opened
 639                                 for the executed processes. See
 640                                 <citerefentry><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 641                                 for details.</para></listitem>
 642                         </varlistentry>
 643
 644                         <varlistentry>
 645                                 <term><varname>TCPWrapName=</varname></term>
 646                                 <listitem><para>If this is a
 647                                 socket-activated service this sets the
 648                                 tcpwrap service name to check the
 649                                 permission for the current connection
 650                                 with. This is only useful in
 651                                 conjunction with socket-activated
 652                                 services, and stream sockets (TCP) in
 653                                 particular. It has no effect on other
 654                                 socket types (e.g. datagram/UDP) and
 655                                 on processes unrelated to socket-based
 656                                 activation. If the tcpwrap
 657                                 verification fails daemon start-up
 658                                 will fail and the connection is
 659                                 terminated. See
 660                                 <citerefentry><refentrytitle>tcpd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 661                                 for details. Note that this option may
 662                                 be used to do access control checks
 663                                 only. Shell commands and commands
 664                                 described in
 665                                 <citerefentry><refentrytitle>hosts_options</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 666                                 are not supported.</para></listitem>
 667                         </varlistentry>
 668
 669                         <varlistentry>
 670                                 <term><varname>CapabilityBoundingSet=</varname></term>
 671
 672                                 <listitem><para>Controls which
 673                                 capabilities to include in the
 674                                 capability bounding set for the
 675                                 executed process. See
 676                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 677                                 for details. Takes a whitespace
 678                                 separated list of capability names as
 679                                 read by
 680                                 <citerefentry><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 681                                 Capabilities listed will be included
 682                                 in the bounding set, all others are
 683                                 removed. If the list of capabilities
 684                                 is prefixed with ~ all but the listed
 685                                 capabilities will be included, the
 686                                 effect of the assignment
 687                                 inverted. Note that this option also
 688                                 effects the respective capabilities in
 689                                 the effective, permitted and
 690                                 inheritable capability sets, on top of
 691                                 what <varname>Capabilities=</varname>
 692                                 does. If this option is not used the
 693                                 capability bounding set is not
 694                                 modified on process execution, hence
 695                                 no limits on the capabilities of the
 696                                 process are
 697                                 enforced.</para></listitem>
 698                         </varlistentry>
 699
 700                         <varlistentry>
 701                                 <term><varname>SecureBits=</varname></term>
 702                                 <listitem><para>Controls the secure
 703                                 bits set for the executed process. See
 704                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 705                                 for details. Takes a list of strings:
 706                                 <option>keep-caps</option>,
 707                                 <option>keep-caps-locked</option>,
 708                                 <option>no-setuid-fixup</option>,
 709                                 <option>no-setuid-fixup-locked</option>,
 710                                 <option>noroot</option> and/or
 711                                 <option>noroot-locked</option>.
 712                                 </para></listitem>
 713                         </varlistentry>
 714
 715                         <varlistentry>
 716                                 <term><varname>Capabilities=</varname></term>
 717                                 <listitem><para>Controls the
 718                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 719                                 set for the executed process. Take a
 720                                 capability string describing the
 721                                 effective, permitted and inherited
 722                                 capability sets as documented in
 723                                 <citerefentry><refentrytitle>cap_from_text</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 724                                 Note that these capability sets are
 725                                 usually influenced by the capabilities
 726                                 attached to the executed file. Due to
 727                                 that
 728                                 <varname>CapabilityBoundingSet=</varname>
 729                                 is probably the much more useful
 730                                 setting.</para></listitem>
 731                         </varlistentry>
 732
 733                         <varlistentry>
 734                                 <term><varname>ControlGroup=</varname></term>
 735
 736                                 <listitem><para>Controls the control
 737                                 groups the executed processes shall be
 738                                 made members of. Takes a
 739                                 space-separated list of cgroup
 740                                 identifiers. A cgroup identifier has a
 741                                 format like
 742                                 <filename>cpu:/foo/bar</filename>,
 743                                 where "cpu" identifies the kernel
 744                                 control group controller used, and
 745                                 <filename>/foo/bar</filename> is the
 746                                 control group path. The controller
 747                                 name and ":" may be omitted in which
 748                                 case the named systemd control group
 749                                 hierarchy is implied. Alternatively,
 750                                 the path and ":" may be omitted, in
 751                                 which case the default control group
 752                                 path for this unit is implied. This
 753                                 option may be used to place executed
 754                                 processes in arbitrary groups in
 755                                 arbitrary hierarchies -- which can be
 756                                 configured externally with additional
 757                                 execution limits. By default systemd
 758                                 will place all executed processes in
 759                                 separate per-unit control groups
 760                                 (named after the unit) in the systemd
 761                                 named hierarchy. Since every process
 762                                 can be in one group per hierarchy only
 763                                 overriding the control group path in
 764                                 the named systemd hierarchy will
 765                                 disable automatic placement in the
 766                                 default group. This option is
 767                                 primarily intended to place executed
 768                                 processes in specific paths in
 769                                 specific kernel controller
 770                                 hierarchies. It is however not
 771                                 recommended to manipulate the service
 772                                 control group path in the systemd
 773                                 named hierarchy. For details about
 774                                 control groups see <ulink
 775                                 url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.</para></listitem>
 776                         </varlistentry>
 777
 778                         <varlistentry>
 779                                 <term><varname>ControlGroupModify=</varname></term>
 780                                 <listitem><para>Takes a boolean
 781                                 argument. If true, the control groups
 782                                 created for this unit will be owned by
 783                                 the user specified with
 784                                 <varname>User=</varname> (and the
 785                                 appropriate group), and he/she can create
 786                                 subgroups as well as add processes to
 787                                 the group.</para></listitem>
 788                         </varlistentry>
 789
 790                         <varlistentry>
 791                                 <term><varname>ControlGroupPersistent=</varname></term>
 792                                 <listitem><para>Takes a boolean
 793                                 argument. If true, the control groups
 794                                 created for this unit will be marked
 795                                 to be persistent, i.e. systemd will
 796                                 not remove them when stopping the
 797                                 unit. The default is false, meaning
 798                                 that the control groups will be
 799                                 removed when the unit is stopped. For
 800                                 details about the semantics of this
 801                                 logic see <ulink
 802                                 url="http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups">PaxControlGroups</ulink>.</para></listitem>
 803                         </varlistentry>
 804
 805                         <varlistentry>
 806                                 <term><varname>ControlGroupAttribute=</varname></term>
 807
 808                                 <listitem><para>Set a specific control
 809                                 group attribute for executed
 810                                 processes, and (if needed) add the
 811                                 executed processes to a cgroup in the
 812                                 hierarchy of the controller the
 813                                 attribute belongs to. Takes two
 814                                 space-separated arguments: the
 815                                 attribute name (syntax is
 816                                 <literal>cpu.shares</literal> where
 817                                 <literal>cpu</literal> refers to a
 818                                 specific controller and
 819                                 <literal>shares</literal> to the
 820                                 attribute name), and the attribute
 821                                 value. Example:
 822                                 <literal>ControlGroupAttribute=cpu.shares
 823                                 512</literal>. If this option is used
 824                                 for an attribute that belongs to a
 825                                 kernel controller hierarchy the unit
 826                                 is not already configured to be added
 827                                 to (for example via the
 828                                 <literal>ControlGroup=</literal>
 829                                 option) then the unit will be added to
 830                                 the controller and the default unit
 831                                 cgroup path is implied. Thus, using
 832                                 <varname>ControlGroupAttribute=</varname>
 833                                 is in most case sufficient to make use
 834                                 of control group enforcements,
 835                                 explicit
 836                                 <varname>ControlGroup=</varname> are
 837                                 only necessary in case the implied
 838                                 default control group path for a
 839                                 service is not desirable. For details
 840                                 about control group attributes see
 841                                 <ulink
 842                                 url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>. This
 843                                 option may appear more than once, in
 844                                 order to set multiple control group
 845                                 attributes.</para></listitem>
 846                         </varlistentry>
 847
 848                         <varlistentry>
 849                                 <term><varname>CPUShares=</varname></term>
 850
 851                                 <listitem><para>Assign the specified
 852                                 overall CPU time shares to the
 853                                 processes executed. Takes an integer
 854                                 value. This controls the
 855                                 <literal>cpu.shares</literal> control
 856                                 group attribute, which defaults to
 857                                 1024. For details about this control
 858                                 group attribute see <ulink
 859                                 url="http://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para></listitem>
 860                         </varlistentry>
 861
 862                         <varlistentry>
 863                                 <term><varname>MemoryLimit=</varname></term>
 864                                 <term><varname>MemorySoftLimit=</varname></term>
 865
 866                                 <listitem><para>Limit the overall memory usage
 867                                 of the executed processes to a certain
 868                                 size. Takes a memory size in bytes. If
 869                                 the value is suffixed with K, M, G or
 870                                 T the specified memory size is parsed
 871                                 as Kilobytes, Megabytes, Gigabytes,
 872                                 or Terabytes (to the base
 873                                 1024), respectively. This controls the
 874                                 <literal>memory.limit_in_bytes</literal>
 875                                 and
 876                                 <literal>memory.soft_limit_in_bytes</literal>
 877                                 control group attributes. For details
 878                                 about these control group attributes
 879                                 see <ulink
 880                                 url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para></listitem>
 881                         </varlistentry>
 882
 883                         <varlistentry>
 884                                 <term><varname>DeviceAllow=</varname></term>
 885                                 <term><varname>DeviceDeny=</varname></term>
 886
 887                                 <listitem><para>Control access to
 888                                 specific device nodes by the executed processes. Takes two
 889                                 space separated strings: a device node
 890                                 path (such as
 891                                 <filename>/dev/null</filename>)
 892                                 followed by a combination of r, w, m
 893                                 to control reading, writing, or
 894                                 creating of the specific device node
 895                                 by the unit, respectively. This controls the
 896                                 <literal>devices.allow</literal>
 897                                 and
 898                                 <literal>devices.deny</literal>
 899                                 control group attributes. For details
 900                                 about these control group attributes
 901                                 see <ulink
 902                                 url="http://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para></listitem>
 903                         </varlistentry>
 904
 905                         <varlistentry>
 906                                 <term><varname>BlockIOWeight=</varname></term>
 907
 908                                 <listitem><para>Set the default or
 909                                 per-device overall block IO weight
 910                                 value for the executed
 911                                 processes. Takes either a single
 912                                 weight value (between 10 and 1000) to
 913                                 set the default block IO weight, or a
 914                                 space separated pair of a file path
 915                                 and a weight value to specify the
 916                                 device specific weight value (Example:
 917                                 "/dev/sda 500"). The file path may be
 918                                 specified as path to a block device
 919                                 node or as any other file in which
 920                                 case the backing block device of the
 921                                 file system of the file is
 922                                 determined. This controls the
 923                                 <literal>blkio.weight</literal> and
 924                                 <literal>blkio.weight_device</literal>
 925                                 control group attributes, which
 926                                 default to 1000. Use this option
 927                                 multiple times to set weights for
 928                                 multiple devices. For details about
 929                                 these control group attributes see
 930                                 <ulink
 931                                 url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>
 932                         </varlistentry>
 933
 934                         <varlistentry>
 935                                 <term><varname>BlockIOReadBandwidth=</varname></term>
 936                                 <term><varname>BlockIOWriteBandwidth=</varname></term>
 937
 938                                 <listitem><para>Set the per-device
 939                                 overall block IO bandwidth limit for
 940                                 the executed processes. Takes a space
 941                                 separated pair of a file path and a
 942                                 bandwidth value (in bytes per second)
 943                                 to specify the device specific
 944                                 bandwidth. The file path may be
 945                                 specified as path to a block device
 946                                 node or as any other file in which
 947                                 case the backing block device of the
 948                                 file system of the file is determined.
 949                                 If the bandwidth is suffixed with K, M,
 950                                 G, or T the specified bandwidth is
 951                                 parsed as Kilobytes, Megabytes,
 952                                 Gigabytes, or Terabytes, respectively (Example:
 953                                 "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0
 954                                 5M"). This controls the
 955                                 <literal>blkio.read_bps_device</literal>
 956                                 and
 957                                 <literal>blkio.write_bps_device</literal>
 958                                 control group attributes. Use this
 959                                 option multiple times to set bandwidth
 960                                 limits for multiple devices. For
 961                                 details about these control group
 962                                 attributes see <ulink
 963                                 url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>
 964                         </varlistentry>
 965
 966                         <varlistentry>
 967                                 <term><varname>ReadWriteDirectories=</varname></term>
 968                                 <term><varname>ReadOnlyDirectories=</varname></term>
 969                                 <term><varname>InaccessibleDirectories=</varname></term>
 970
 971                                 <listitem><para>Sets up a new
 972                                 file-system name space for executed
 973                                 processes. These options may be used
 974                                 to limit access a process might have
 975                                 to the main file-system
 976                                 hierarchy. Each setting takes a
 977                                 space-separated list of absolute
 978                                 directory paths. Directories listed in
 979                                 <varname>ReadWriteDirectories=</varname>
 980                                 are accessible from within the
 981                                 namespace with the same access rights
 982                                 as from outside. Directories listed in
 983                                 <varname>ReadOnlyDirectories=</varname>
 984                                 are accessible for reading only,
 985                                 writing will be refused even if the
 986                                 usual file access controls would
 987                                 permit this. Directories listed in
 988                                 <varname>InaccessibleDirectories=</varname>
 989                                 will be made inaccessible for processes
 990                                 inside the namespace. Note that
 991                                 restricting access with these options
 992                                 does not extend to submounts of a
 993                                 directory. You must list submounts
 994                                 separately in these settings to
 995                                 ensure the same limited access. These
 996                                 options may be specified more than
 997                                 once in which case all directories
 998                                 listed will have limited access from
 999                                 within the
1000                                 namespace.</para></listitem>
1001                         </varlistentry>
1002
1003                         <varlistentry>
1004                                 <term><varname>PrivateTmp=</varname></term>
1005
1006                                 <listitem><para>Takes a boolean
1007                                 argument. If true sets up a new file
1008                                 system namespace for the executed
1009                                 processes and mounts a private
1010                                 <filename>/tmp</filename> directory
1011                                 inside it, that is not shared by
1012                                 processes outside of the
1013                                 namespace. This is useful to secure
1014                                 access to temporary files of the
1015                                 process, but makes sharing between
1016                                 processes via
1017                                 <filename>/tmp</filename>
1018                                 impossible. Defaults to
1019                                 false.</para></listitem>
1020                         </varlistentry>
1021
1022                         <varlistentry>
1023                                 <term><varname>PrivateNetwork=</varname></term>
1024
1025                                 <listitem><para>Takes a boolean
1026                                 argument. If true sets up a new
1027                                 network namespace for the executed
1028                                 processes and configures only the
1029                                 loopback network device
1030                                 <literal>lo</literal> inside it. No
1031                                 other network devices will be
1032                                 available to the executed process.
1033                                 This is useful to securely turn off
1034                                 network access by the executed
1035                                 process. Defaults to
1036                                 false.</para></listitem>
1037                         </varlistentry>
1038
1039                         <varlistentry>
1040                                 <term><varname>MountFlags=</varname></term>
1041
1042                                 <listitem><para>Takes a mount
1043                                 propagation flag:
1044                                 <option>shared</option>,
1045                                 <option>slave</option> or
1046                                 <option>private</option>, which
1047                                 control whether the file system
1048                                 namespace set up for this unit's
1049                                 processes will receive or propagate
1050                                 new mounts. See
1051                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>1</manvolnum></citerefentry>
1052                                 for details. Default to
1053                                 <option>shared</option>.</para></listitem>
1054                         </varlistentry>
1055
1056                         <varlistentry>
1057                                 <term><varname>UtmpIdentifier=</varname></term>
1058
1059                                 <listitem><para>Takes a four
1060                                 character identifier string for an
1061                                 utmp/wtmp entry for this service. This
1062                                 should only be set for services such
1063                                 as <command>getty</command>
1064                                 implementations where utmp/wtmp
1065                                 entries must be created and cleared
1066                                 before and after execution. If the
1067                                 configured string is longer than four
1068                                 characters it is truncated and the
1069                                 terminal four characters are
1070                                 used. This setting interprets %I style
1071                                 string replacements. This setting is
1072                                 unset by default, i.e. no utmp/wtmp
1073                                 entries are created or cleaned up for
1074                                 this service.</para></listitem>
1075                         </varlistentry>
1076
1077                         <varlistentry>
1078                                 <term><varname>IgnoreSIGPIPE=</varname></term>
1079
1080                                 <listitem><para>Takes a boolean
1081                                 argument. If true causes SIGPIPE to be
1082                                 ignored in the executed
1083                                 process. Defaults to true, since
1084                                 SIGPIPE generally is useful only in
1085                                 shell pipelines.</para></listitem>
1086                         </varlistentry>
1087
1088                         <varlistentry>
1089                                 <term><varname>NoNewPrivileges=</varname></term>
1090
1091                                 <listitem><para>Takes a boolean
1092                                 argument. If true ensures that the
1093                                 service process and all its children
1094                                 can never gain new privileges. This
1095                                 option is more powerful than the respective
1096                                 secure bits flags (see above), as it
1097                                 also prohibits UID changes of any
1098                                 kind. This is the simplest, most
1099                                 effective way to ensure that a process
1100                                 and its children can never elevate
1101                                 privileges again.</para></listitem>
1102                         </varlistentry>
1103
1104                         <varlistentry>
1105                                 <term><varname>SystemCallFilter=</varname></term>
1106
1107                                 <listitem><para>Takes a space
1108                                 separated list of system call
1109                                 names. If this setting is used all
1110                                 system calls executed by the unit
1111                                 process except for the listed ones
1112                                 will result in immediate process
1113                                 termination with the SIGSYS signal
1114                                 (whitelisting). If the first character
1115                                 of the list is <literal>~</literal>
1116                                 the effect is inverted: only the
1117                                 listed system calls will result in
1118                                 immediate process termination
1119                                 (blacklisting). If this option is used
1120                                 <varname>NoNewPrivileges=yes</varname>
1121                                 is implied. This feature makes use of
1122                                 the Secure Computing Mode 2 interfaces
1123                                 of the kernel ('seccomp filtering')
1124                                 and is useful for enforcing a minimal
1125                                 sandboxing environment. Note that the
1126                                 <function>execve</function>,
1127                                 <function>rt_sigreturn</function>,
1128                                 <function>sigreturn</function>,
1129                                 <function>exit_group</function>,
1130                                 <function>exit</function> system calls
1131                                 are implicitly whitelisted and don't
1132                                 need to be listed
1133                                 explicitly.</para></listitem>
1134                         </varlistentry>
1135
1136                 </variablelist>
1137         </refsect1>
1138
1139         <refsect1>
1140                   <title>See Also</title>
1141                   <para>
1142                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1143                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1144                           <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1145                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1146                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1147                           <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1148                           <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1149                           <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1150                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1151                   </para>
1152         </refsect1>
1153
1154 </refentry>