man/systemd.exec.xml

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   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
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  19   Lesser General Public License for more details.
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  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. The available priority
 218                                 range depends on the selected CPU
 219                                 scheduling policy (see above). For
 220                                 real-time scheduling policies an
 221                                 integer between 1 (lowest priority)
 222                                 and 99 (highest priority) can be used.
 223                                 See <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 224                                 for details.
 225                                 </para></listitem>
 226                         </varlistentry>
 227
 228                         <varlistentry>
 229                                 <term><varname>CPUSchedulingResetOnFork=</varname></term>
 230
 231                                 <listitem><para>Takes a boolean
 232                                 argument. If true elevated CPU
 233                                 scheduling priorities and policies
 234                                 will be reset when the executed
 235                                 processes fork, and can hence not leak
 236                                 into child processes. See
 237                                 <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 238                                 for details. Defaults to false.</para></listitem>
 239                         </varlistentry>
 240
 241                         <varlistentry>
 242                                 <term><varname>CPUAffinity=</varname></term>
 243
 244                                 <listitem><para>Controls the CPU
 245                                 affinity of the executed
 246                                 processes. Takes a space-separated
 247                                 list of CPU indexes. See
 248                                 <citerefentry><refentrytitle>sched_setaffinity</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 249                                 for details.</para></listitem>
 250                         </varlistentry>
 251
 252                         <varlistentry>
 253                                 <term><varname>UMask=</varname></term>
 254
 255                                 <listitem><para>Controls the file mode
 256                                 creation mask. Takes an access mode in
 257                                 octal notation. See
 258                                 <citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 259                                 for details. Defaults to
 260                                 0022.</para></listitem>
 261                         </varlistentry>
 262
 263                         <varlistentry>
 264                                 <term><varname>Environment=</varname></term>
 265
 266                                 <listitem><para>Sets environment
 267                                 variables for executed
 268                                 processes. Takes a space-separated
 269                                 list of variable assignments. This
 270                                 option may be specified more than once
 271                                 in which case all listed variables
 272                                 will be set. If the same variable is
 273                                 set twice the later setting will
 274                                 override the earlier setting. See
 275                                 <citerefentry><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 276                                 for details.</para></listitem>
 277                         </varlistentry>
 278                         <varlistentry>
 279                                 <term><varname>EnvironmentFile=</varname></term>
 280                                 <listitem><para>Similar to
 281                                 <varname>Environment=</varname> but
 282                                 reads the environment variables from a
 283                                 text file. The text file should
 284                                 contain new-line separated variable
 285                                 assignments. Empty lines and lines
 286                                 starting with ; or # will be ignored,
 287                                 which may be used for commenting. The
 288                                 parser strips leading and
 289                                 trailing whitespace from the values
 290                                 of assignments, unless you use
 291                                 double quotes (").
 292                                 The
 293                                 argument passed should be an absolute
 294                                 file name, optionally prefixed with
 295                                 "-", which indicates that if the file
 296                                 does not exist it won't be read and no
 297                                 error or warning message is
 298                                 logged. The files listed with this
 299                                 directive will be read shortly before
 300                                 the process is executed. Settings from
 301                                 these files override settings made
 302                                 with
 303                                 <varname>Environment=</varname>. If
 304                                 the same variable is set twice from
 305                                 these files the files will be read in
 306                                 the order they are specified and the
 307                                 later setting will override the
 308                                 earlier setting. </para></listitem>
 309                         </varlistentry>
 310
 311                         <varlistentry>
 312                                 <term><varname>StandardInput=</varname></term>
 313                                 <listitem><para>Controls where file
 314                                 descriptor 0 (STDIN) of the executed
 315                                 processes is connected to. Takes one
 316                                 of <option>null</option>,
 317                                 <option>tty</option>,
 318                                 <option>tty-force</option>,
 319                                 <option>tty-fail</option> or
 320                                 <option>socket</option>. If
 321                                 <option>null</option> is selected
 322                                 standard input will be connected to
 323                                 <filename>/dev/null</filename>,
 324                                 i.e. all read attempts by the process
 325                                 will result in immediate EOF. If
 326                                 <option>tty</option> is selected
 327                                 standard input is connected to a TTY
 328                                 (as configured by
 329                                 <varname>TTYPath=</varname>, see
 330                                 below) and the executed process
 331                                 becomes the controlling process of the
 332                                 terminal. If the terminal is already
 333                                 being controlled by another process the
 334                                 executed process waits until the current
 335                                 controlling process releases the
 336                                 terminal.
 337                                 <option>tty-force</option>
 338                                 is similar to <option>tty</option>,
 339                                 but the executed process is forcefully
 340                                 and immediately made the controlling
 341                                 process of the terminal, potentially
 342                                 removing previous controlling
 343                                 processes from the
 344                                 terminal. <option>tty-fail</option> is
 345                                 similar to <option>tty</option> but if
 346                                 the terminal already has a controlling
 347                                 process start-up of the executed
 348                                 process fails.  The
 349                                 <option>socket</option> option is only
 350                                 valid in socket-activated services,
 351                                 and only when the socket configuration
 352                                 file (see
 353                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 354                                 for details) specifies a single socket
 355                                 only. If this option is set standard
 356                                 input will be connected to the socket
 357                                 the service was activated from, which
 358                                 is primarily useful for compatibility
 359                                 with daemons designed for use with the
 360                                 traditional
 361                                 <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 362                                 daemon. This setting defaults to
 363                                 <option>null</option>.</para></listitem>
 364                         </varlistentry>
 365                         <varlistentry>
 366                                 <term><varname>StandardOutput=</varname></term>
 367                                 <listitem><para>Controls where file
 368                                 descriptor 1 (STDOUT) of the executed
 369                                 processes is connected to. Takes one
 370                                 of <option>inherit</option>,
 371                                 <option>null</option>,
 372                                 <option>tty</option>,
 373                                 <option>syslog</option>,
 374                                 <option>kmsg</option>,
 375                                 <option>journal</option>,
 376                                 <option>syslog+console</option>,
 377                                 <option>kmsg+console</option>,
 378                                 <option>journal+console</option> or
 379                                 <option>socket</option>. If set to
 380                                 <option>inherit</option> the file
 381                                 descriptor of standard input is
 382                                 duplicated for standard output. If set
 383                                 to <option>null</option> standard
 384                                 output will be connected to
 385                                 <filename>/dev/null</filename>,
 386                                 i.e. everything written to it will be
 387                                 lost. If set to <option>tty</option>
 388                                 standard output will be connected to a
 389                                 tty (as configured via
 390                                 <varname>TTYPath=</varname>, see
 391                                 below). If the TTY is used for output
 392                                 only the executed process will not
 393                                 become the controlling process of the
 394                                 terminal, and will not fail or wait
 395                                 for other processes to release the
 396                                 terminal. <option>syslog</option>
 397                                 connects standard output to the
 398                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 399                                 system syslog
 400                                 service. <option>kmsg</option>
 401                                 connects it with the kernel log buffer
 402                                 which is accessible via
 403                                 <citerefentry><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>. <option>journal</option>
 404                                 connects it with the journal which is
 405                                 accessible via
 406                                 <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 407                                 (Note that everything that is written
 408                                 to syslog or kmsg is implicitly stored
 409                                 in the journal as well, those options
 410                                 are hence supersets of this
 411                                 one). <option>syslog+console</option>,
 412                                 <option>journal+console</option> and
 413                                 <option>kmsg+console</option> work
 414                                 similarly but copy the output to the
 415                                 system console as
 416                                 well. <option>socket</option> connects
 417                                 standard output to a socket from
 418                                 socket activation, semantics are
 419                                 similar to the respective option of
 420                                 <varname>StandardInput=</varname>.
 421                                 This setting defaults to the value set
 422                                 with
 423                                 <option>DefaultStandardOutput=</option>
 424                                 in
 425                                 <citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 426                                 which defaults to
 427                                 <option>journal</option>.</para></listitem>
 428                         </varlistentry>
 429                         <varlistentry>
 430                                 <term><varname>StandardError=</varname></term>
 431                                 <listitem><para>Controls where file
 432                                 descriptor 2 (STDERR) of the executed
 433                                 processes is connected to. The
 434                                 available options are identical to
 435                                 those of
 436                                 <varname>StandardOutput=</varname>,
 437                                 with one exception: if set to
 438                                 <option>inherit</option> the file
 439                                 descriptor used for standard output is
 440                                 duplicated for standard error. This
 441                                 setting defaults to the value set with
 442                                 <option>DefaultStandardError=</option>
 443                                 in
 444                                 <citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 445                                 which defaults to
 446                                 <option>inherit</option>.</para></listitem>
 447                         </varlistentry>
 448                         <varlistentry>
 449                                 <term><varname>TTYPath=</varname></term>
 450                                 <listitem><para>Sets the terminal
 451                                 device node to use if standard input,
 452                                 output or stderr are connected to a
 453                                 TTY (see above). Defaults to
 454                                 <filename>/dev/console</filename>.</para></listitem>
 455                         </varlistentry>
 456                         <varlistentry>
 457                                 <term><varname>TTYReset=</varname></term>
 458                                 <listitem><para>Reset the terminal
 459                                 device specified with
 460                                 <varname>TTYPath=</varname> before and
 461                                 after execution. Defaults to
 462                                 <literal>no</literal>.</para></listitem>
 463                         </varlistentry>
 464                         <varlistentry>
 465                                 <term><varname>TTYVHangup=</varname></term>
 466                                 <listitem><para>Disconnect all clients
 467                                 which have opened the terminal device
 468                                 specified with
 469                                 <varname>TTYPath=</varname>
 470                                 before and after execution. Defaults
 471                                 to
 472                                 <literal>no</literal>.</para></listitem>
 473                         </varlistentry>
 474                         <varlistentry>
 475                                 <term><varname>TTYVTDisallocate=</varname></term>
 476                                 <listitem><para>If the terminal
 477                                 device specified with
 478                                 <varname>TTYPath=</varname> is a
 479                                 virtual console terminal try to
 480                                 deallocate the TTY before and after
 481                                 execution. This ensures that the
 482                                 screen and scrollback buffer is
 483                                 cleared. Defaults to
 484                                 <literal>no</literal>.</para></listitem>
 485                         </varlistentry>
 486                         <varlistentry>
 487                                 <term><varname>SyslogIdentifier=</varname></term>
 488                                 <listitem><para>Sets the process name
 489                                 to prefix log lines sent to syslog or
 490                                 the kernel log buffer with. If not set
 491                                 defaults to the process name of the
 492                                 executed process. This option is only
 493                                 useful when
 494                                 <varname>StandardOutput=</varname> or
 495                                 <varname>StandardError=</varname> are
 496                                 set to <option>syslog</option> or
 497                                 <option>kmsg</option>.</para></listitem>
 498                         </varlistentry>
 499                         <varlistentry>
 500                                 <term><varname>SyslogFacility=</varname></term>
 501                                 <listitem><para>Sets the syslog
 502                                 facility to use when logging to
 503                                 syslog. One of <option>kern</option>,
 504                                 <option>user</option>,
 505                                 <option>mail</option>,
 506                                 <option>daemon</option>,
 507                                 <option>auth</option>,
 508                                 <option>syslog</option>,
 509                                 <option>lpr</option>,
 510                                 <option>news</option>,
 511                                 <option>uucp</option>,
 512                                 <option>cron</option>,
 513                                 <option>authpriv</option>,
 514                                 <option>ftp</option>,
 515                                 <option>local0</option>,
 516                                 <option>local1</option>,
 517                                 <option>local2</option>,
 518                                 <option>local3</option>,
 519                                 <option>local4</option>,
 520                                 <option>local5</option>,
 521                                 <option>local6</option> or
 522                                 <option>local7</option>. See
 523                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 524                                 for details. This option is only
 525                                 useful when
 526                                 <varname>StandardOutput=</varname> or
 527                                 <varname>StandardError=</varname> are
 528                                 set to <option>syslog</option>.
 529                                 Defaults to
 530                                 <option>daemon</option>.</para></listitem>
 531                         </varlistentry>
 532                         <varlistentry>
 533                                 <term><varname>SyslogLevel=</varname></term>
 534                                 <listitem><para>Default syslog level
 535                                 to use when logging to syslog or the
 536                                 kernel log buffer. One of
 537                                 <option>emerg</option>,
 538                                 <option>alert</option>,
 539                                 <option>crit</option>,
 540                                 <option>err</option>,
 541                                 <option>warning</option>,
 542                                 <option>notice</option>,
 543                                 <option>info</option>,
 544                                 <option>debug</option>. See
 545                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 546                                 for details. This option is only
 547                                 useful when
 548                                 <varname>StandardOutput=</varname> or
 549                                 <varname>StandardError=</varname> are
 550                                 set to <option>syslog</option> or
 551                                 <option>kmsg</option>. Note that
 552                                 individual lines output by the daemon
 553                                 might be prefixed with a different log
 554                                 level which can be used to override
 555                                 the default log level specified
 556                                 here. The interpretation of these
 557                                 prefixes may be disabled with
 558                                 <varname>SyslogLevelPrefix=</varname>,
 559                                 see below. For details see
 560                                 <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 561
 562                                 Defaults to
 563                                 <option>info</option>.</para></listitem>
 564                         </varlistentry>
 565
 566                         <varlistentry>
 567                                 <term><varname>SyslogLevelPrefix=</varname></term>
 568                                 <listitem><para>Takes a boolean
 569                                 argument. If true and
 570                                 <varname>StandardOutput=</varname> or
 571                                 <varname>StandardError=</varname> are
 572                                 set to <option>syslog</option>,
 573                                 <option>kmsg</option> or
 574                                 <option>journal</option>, log lines
 575                                 written by the executed process that
 576                                 are prefixed with a log level will be
 577                                 passed on to syslog with this log
 578                                 level set but the prefix removed. If
 579                                 set to false, the interpretation of
 580                                 these prefixes is disabled and the
 581                                 logged lines are passed on as-is. For
 582                                 details about this prefixing see
 583                                 <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 584                                 Defaults to true.</para></listitem>
 585                         </varlistentry>
 586
 587                         <varlistentry>
 588                                 <term><varname>TimerSlackNSec=</varname></term>
 589                                 <listitem><para>Sets the timer slack
 590                                 in nanoseconds for the executed
 591                                 processes. The timer slack controls
 592                                 the accuracy of wake-ups triggered by
 593                                 timers. See
 594                                 <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 595                                 for more information. Note that in
 596                                 contrast to most other time span
 597                                 definitions this parameter takes an
 598                                 integer value in nano-seconds if no
 599                                 unit is specified. The usual time
 600                                 units are understood
 601                                 too.</para></listitem>
 602                         </varlistentry>
 603
 604                         <varlistentry>
 605                                 <term><varname>LimitCPU=</varname></term>
 606                                 <term><varname>LimitFSIZE=</varname></term>
 607                                 <term><varname>LimitDATA=</varname></term>
 608                                 <term><varname>LimitSTACK=</varname></term>
 609                                 <term><varname>LimitCORE=</varname></term>
 610                                 <term><varname>LimitRSS=</varname></term>
 611                                 <term><varname>LimitNOFILE=</varname></term>
 612                                 <term><varname>LimitAS=</varname></term>
 613                                 <term><varname>LimitNPROC=</varname></term>
 614                                 <term><varname>LimitMEMLOCK=</varname></term>
 615                                 <term><varname>LimitLOCKS=</varname></term>
 616                                 <term><varname>LimitSIGPENDING=</varname></term>
 617                                 <term><varname>LimitMSGQUEUE=</varname></term>
 618                                 <term><varname>LimitNICE=</varname></term>
 619                                 <term><varname>LimitRTPRIO=</varname></term>
 620                                 <term><varname>LimitRTTIME=</varname></term>
 621                                 <listitem><para>These settings control
 622                                 various resource limits for executed
 623                                 processes. See
 624                                 <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 625                                 for details. Use the string
 626                                 <varname>infinity</varname> to
 627                                 configure no limit on a specific
 628                                 resource.</para></listitem>
 629                         </varlistentry>
 630
 631                         <varlistentry>
 632                                 <term><varname>PAMName=</varname></term>
 633                                 <listitem><para>Sets the PAM service
 634                                 name to set up a session as. If set
 635                                 the executed process will be
 636                                 registered as a PAM session under the
 637                                 specified service name. This is only
 638                                 useful in conjunction with the
 639                                 <varname>User=</varname> setting. If
 640                                 not set no PAM session will be opened
 641                                 for the executed processes. See
 642                                 <citerefentry><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 643                                 for details.</para></listitem>
 644                         </varlistentry>
 645
 646                         <varlistentry>
 647                                 <term><varname>TCPWrapName=</varname></term>
 648                                 <listitem><para>If this is a
 649                                 socket-activated service this sets the
 650                                 tcpwrap service name to check the
 651                                 permission for the current connection
 652                                 with. This is only useful in
 653                                 conjunction with socket-activated
 654                                 services, and stream sockets (TCP) in
 655                                 particular. It has no effect on other
 656                                 socket types (e.g. datagram/UDP) and
 657                                 on processes unrelated to socket-based
 658                                 activation. If the tcpwrap
 659                                 verification fails daemon start-up
 660                                 will fail and the connection is
 661                                 terminated. See
 662                                 <citerefentry><refentrytitle>tcpd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 663                                 for details. Note that this option may
 664                                 be used to do access control checks
 665                                 only. Shell commands and commands
 666                                 described in
 667                                 <citerefentry><refentrytitle>hosts_options</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 668                                 are not supported.</para></listitem>
 669                         </varlistentry>
 670
 671                         <varlistentry>
 672                                 <term><varname>CapabilityBoundingSet=</varname></term>
 673
 674                                 <listitem><para>Controls which
 675                                 capabilities to include in the
 676                                 capability bounding set for the
 677                                 executed process. See
 678                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 679                                 for details. Takes a whitespace
 680                                 separated list of capability names as
 681                                 read by
 682                                 <citerefentry><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 683                                 Capabilities listed will be included
 684                                 in the bounding set, all others are
 685                                 removed. If the list of capabilities
 686                                 is prefixed with ~ all but the listed
 687                                 capabilities will be included, the
 688                                 effect of the assignment
 689                                 inverted. Note that this option also
 690                                 effects the respective capabilities in
 691                                 the effective, permitted and
 692                                 inheritable capability sets, on top of
 693                                 what <varname>Capabilities=</varname>
 694                                 does. If this option is not used the
 695                                 capability bounding set is not
 696                                 modified on process execution, hence
 697                                 no limits on the capabilities of the
 698                                 process are
 699                                 enforced.</para></listitem>
 700                         </varlistentry>
 701
 702                         <varlistentry>
 703                                 <term><varname>SecureBits=</varname></term>
 704                                 <listitem><para>Controls the secure
 705                                 bits set for the executed process. See
 706                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 707                                 for details. Takes a list of strings:
 708                                 <option>keep-caps</option>,
 709                                 <option>keep-caps-locked</option>,
 710                                 <option>no-setuid-fixup</option>,
 711                                 <option>no-setuid-fixup-locked</option>,
 712                                 <option>noroot</option> and/or
 713                                 <option>noroot-locked</option>.
 714                                 </para></listitem>
 715                         </varlistentry>
 716
 717                         <varlistentry>
 718                                 <term><varname>Capabilities=</varname></term>
 719                                 <listitem><para>Controls the
 720                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 721                                 set for the executed process. Take a
 722                                 capability string describing the
 723                                 effective, permitted and inherited
 724                                 capability sets as documented in
 725                                 <citerefentry><refentrytitle>cap_from_text</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 726                                 Note that these capability sets are
 727                                 usually influenced by the capabilities
 728                                 attached to the executed file. Due to
 729                                 that
 730                                 <varname>CapabilityBoundingSet=</varname>
 731                                 is probably the much more useful
 732                                 setting.</para></listitem>
 733                         </varlistentry>
 734
 735                         <varlistentry>
 736                                 <term><varname>ControlGroup=</varname></term>
 737
 738                                 <listitem><para>Controls the control
 739                                 groups the executed processes shall be
 740                                 made members of. Takes a
 741                                 space-separated list of cgroup
 742                                 identifiers. A cgroup identifier has a
 743                                 format like
 744                                 <filename>cpu:/foo/bar</filename>,
 745                                 where "cpu" identifies the kernel
 746                                 control group controller used, and
 747                                 <filename>/foo/bar</filename> is the
 748                                 control group path. The controller
 749                                 name and ":" may be omitted in which
 750                                 case the named systemd control group
 751                                 hierarchy is implied. Alternatively,
 752                                 the path and ":" may be omitted, in
 753                                 which case the default control group
 754                                 path for this unit is implied. This
 755                                 option may be used to place executed
 756                                 processes in arbitrary groups in
 757                                 arbitrary hierarchies -- which can be
 758                                 configured externally with additional
 759                                 execution limits. By default systemd
 760                                 will place all executed processes in
 761                                 separate per-unit control groups
 762                                 (named after the unit) in the systemd
 763                                 named hierarchy. Since every process
 764                                 can be in one group per hierarchy only
 765                                 overriding the control group path in
 766                                 the named systemd hierarchy will
 767                                 disable automatic placement in the
 768                                 default group. This option is
 769                                 primarily intended to place executed
 770                                 processes in specific paths in
 771                                 specific kernel controller
 772                                 hierarchies. It is however not
 773                                 recommended to manipulate the service
 774                                 control group path in the systemd
 775                                 named hierarchy. For details about
 776                                 control groups see <ulink
 777                                 url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.</para></listitem>
 778                         </varlistentry>
 779
 780                         <varlistentry>
 781                                 <term><varname>ControlGroupModify=</varname></term>
 782                                 <listitem><para>Takes a boolean
 783                                 argument. If true, the control groups
 784                                 created for this unit will be owned by
 785                                 the user specified with
 786                                 <varname>User=</varname> (and the
 787                                 appropriate group), and he/she can create
 788                                 subgroups as well as add processes to
 789                                 the group.</para></listitem>
 790                         </varlistentry>
 791
 792                         <varlistentry>
 793                                 <term><varname>ControlGroupPersistent=</varname></term>
 794                                 <listitem><para>Takes a boolean
 795                                 argument. If true, the control groups
 796                                 created for this unit will be marked
 797                                 to be persistent, i.e. systemd will
 798                                 not remove them when stopping the
 799                                 unit. The default is false, meaning
 800                                 that the control groups will be
 801                                 removed when the unit is stopped. For
 802                                 details about the semantics of this
 803                                 logic see <ulink
 804                                 url="http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups">PaxControlGroups</ulink>.</para></listitem>
 805                         </varlistentry>
 806
 807                         <varlistentry>
 808                                 <term><varname>ControlGroupAttribute=</varname></term>
 809
 810                                 <listitem><para>Set a specific control
 811                                 group attribute for executed
 812                                 processes, and (if needed) add the
 813                                 executed processes to a cgroup in the
 814                                 hierarchy of the controller the
 815                                 attribute belongs to. Takes two
 816                                 space-separated arguments: the
 817                                 attribute name (syntax is
 818                                 <literal>cpu.shares</literal> where
 819                                 <literal>cpu</literal> refers to a
 820                                 specific controller and
 821                                 <literal>shares</literal> to the
 822                                 attribute name), and the attribute
 823                                 value. Example:
 824                                 <literal>ControlGroupAttribute=cpu.shares
 825                                 512</literal>. If this option is used
 826                                 for an attribute that belongs to a
 827                                 kernel controller hierarchy the unit
 828                                 is not already configured to be added
 829                                 to (for example via the
 830                                 <literal>ControlGroup=</literal>
 831                                 option) then the unit will be added to
 832                                 the controller and the default unit
 833                                 cgroup path is implied. Thus, using
 834                                 <varname>ControlGroupAttribute=</varname>
 835                                 is in most case sufficient to make use
 836                                 of control group enforcements,
 837                                 explicit
 838                                 <varname>ControlGroup=</varname> are
 839                                 only necessary in case the implied
 840                                 default control group path for a
 841                                 service is not desirable. For details
 842                                 about control group attributes see
 843                                 <ulink
 844                                 url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>. This
 845                                 option may appear more than once, in
 846                                 order to set multiple control group
 847                                 attributes.</para></listitem>
 848                         </varlistentry>
 849
 850                         <varlistentry>
 851                                 <term><varname>CPUShares=</varname></term>
 852
 853                                 <listitem><para>Assign the specified
 854                                 overall CPU time shares to the
 855                                 processes executed. Takes an integer
 856                                 value. This controls the
 857                                 <literal>cpu.shares</literal> control
 858                                 group attribute, which defaults to
 859                                 1024. For details about this control
 860                                 group attribute see <ulink
 861                                 url="http://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para></listitem>
 862                         </varlistentry>
 863
 864                         <varlistentry>
 865                                 <term><varname>MemoryLimit=</varname></term>
 866                                 <term><varname>MemorySoftLimit=</varname></term>
 867
 868                                 <listitem><para>Limit the overall memory usage
 869                                 of the executed processes to a certain
 870                                 size. Takes a memory size in bytes. If
 871                                 the value is suffixed with K, M, G or
 872                                 T the specified memory size is parsed
 873                                 as Kilobytes, Megabytes, Gigabytes,
 874                                 or Terabytes (to the base
 875                                 1024), respectively. This controls the
 876                                 <literal>memory.limit_in_bytes</literal>
 877                                 and
 878                                 <literal>memory.soft_limit_in_bytes</literal>
 879                                 control group attributes. For details
 880                                 about these control group attributes
 881                                 see <ulink
 882                                 url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para></listitem>
 883                         </varlistentry>
 884
 885                         <varlistentry>
 886                                 <term><varname>DeviceAllow=</varname></term>
 887                                 <term><varname>DeviceDeny=</varname></term>
 888
 889                                 <listitem><para>Control access to
 890                                 specific device nodes by the executed processes. Takes two
 891                                 space separated strings: a device node
 892                                 path (such as
 893                                 <filename>/dev/null</filename>)
 894                                 followed by a combination of r, w, m
 895                                 to control reading, writing, or
 896                                 creating of the specific device node
 897                                 by the unit, respectively. This controls the
 898                                 <literal>devices.allow</literal>
 899                                 and
 900                                 <literal>devices.deny</literal>
 901                                 control group attributes. For details
 902                                 about these control group attributes
 903                                 see <ulink
 904                                 url="http://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para></listitem>
 905                         </varlistentry>
 906
 907                         <varlistentry>
 908                                 <term><varname>BlockIOWeight=</varname></term>
 909
 910                                 <listitem><para>Set the default or
 911                                 per-device overall block IO weight
 912                                 value for the executed
 913                                 processes. Takes either a single
 914                                 weight value (between 10 and 1000) to
 915                                 set the default block IO weight, or a
 916                                 space separated pair of a file path
 917                                 and a weight value to specify the
 918                                 device specific weight value (Example:
 919                                 "/dev/sda 500"). The file path may be
 920                                 specified as path to a block device
 921                                 node or as any other file in which
 922                                 case the backing block device of the
 923                                 file system of the file is
 924                                 determined. This controls the
 925                                 <literal>blkio.weight</literal> and
 926                                 <literal>blkio.weight_device</literal>
 927                                 control group attributes, which
 928                                 default to 1000. Use this option
 929                                 multiple times to set weights for
 930                                 multiple devices. For details about
 931                                 these control group attributes see
 932                                 <ulink
 933                                 url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>
 934                         </varlistentry>
 935
 936                         <varlistentry>
 937                                 <term><varname>BlockIOReadBandwidth=</varname></term>
 938                                 <term><varname>BlockIOWriteBandwidth=</varname></term>
 939
 940                                 <listitem><para>Set the per-device
 941                                 overall block IO bandwidth limit for
 942                                 the executed processes. Takes a space
 943                                 separated pair of a file path and a
 944                                 bandwidth value (in bytes per second)
 945                                 to specify the device specific
 946                                 bandwidth. The file path may be
 947                                 specified as path to a block device
 948                                 node or as any other file in which
 949                                 case the backing block device of the
 950                                 file system of the file is determined.
 951                                 If the bandwidth is suffixed with K, M,
 952                                 G, or T the specified bandwidth is
 953                                 parsed as Kilobytes, Megabytes,
 954                                 Gigabytes, or Terabytes, respectively (Example:
 955                                 "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0
 956                                 5M"). This controls the
 957                                 <literal>blkio.read_bps_device</literal>
 958                                 and
 959                                 <literal>blkio.write_bps_device</literal>
 960                                 control group attributes. Use this
 961                                 option multiple times to set bandwidth
 962                                 limits for multiple devices. For
 963                                 details about these control group
 964                                 attributes see <ulink
 965                                 url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem>
 966                         </varlistentry>
 967
 968                         <varlistentry>
 969                                 <term><varname>ReadWriteDirectories=</varname></term>
 970                                 <term><varname>ReadOnlyDirectories=</varname></term>
 971                                 <term><varname>InaccessibleDirectories=</varname></term>
 972
 973                                 <listitem><para>Sets up a new
 974                                 file-system name space for executed
 975                                 processes. These options may be used
 976                                 to limit access a process might have
 977                                 to the main file-system
 978                                 hierarchy. Each setting takes a
 979                                 space-separated list of absolute
 980                                 directory paths. Directories listed in
 981                                 <varname>ReadWriteDirectories=</varname>
 982                                 are accessible from within the
 983                                 namespace with the same access rights
 984                                 as from outside. Directories listed in
 985                                 <varname>ReadOnlyDirectories=</varname>
 986                                 are accessible for reading only,
 987                                 writing will be refused even if the
 988                                 usual file access controls would
 989                                 permit this. Directories listed in
 990                                 <varname>InaccessibleDirectories=</varname>
 991                                 will be made inaccessible for processes
 992                                 inside the namespace. Note that
 993                                 restricting access with these options
 994                                 does not extend to submounts of a
 995                                 directory. You must list submounts
 996                                 separately in these settings to
 997                                 ensure the same limited access. These
 998                                 options may be specified more than
 999                                 once in which case all directories
1000                                 listed will have limited access from
1001                                 within the
1002                                 namespace.</para></listitem>
1003                         </varlistentry>
1004
1005                         <varlistentry>
1006                                 <term><varname>PrivateTmp=</varname></term>
1007
1008                                 <listitem><para>Takes a boolean
1009                                 argument. If true sets up a new file
1010                                 system namespace for the executed
1011                                 processes and mounts a private
1012                                 <filename>/tmp</filename> directory
1013                                 inside it, that is not shared by
1014                                 processes outside of the
1015                                 namespace. This is useful to secure
1016                                 access to temporary files of the
1017                                 process, but makes sharing between
1018                                 processes via
1019                                 <filename>/tmp</filename>
1020                                 impossible. Defaults to
1021                                 false.</para></listitem>
1022                         </varlistentry>
1023
1024                         <varlistentry>
1025                                 <term><varname>PrivateNetwork=</varname></term>
1026
1027                                 <listitem><para>Takes a boolean
1028                                 argument. If true sets up a new
1029                                 network namespace for the executed
1030                                 processes and configures only the
1031                                 loopback network device
1032                                 <literal>lo</literal> inside it. No
1033                                 other network devices will be
1034                                 available to the executed process.
1035                                 This is useful to securely turn off
1036                                 network access by the executed
1037                                 process. Defaults to
1038                                 false.</para></listitem>
1039                         </varlistentry>
1040
1041                         <varlistentry>
1042                                 <term><varname>MountFlags=</varname></term>
1043
1044                                 <listitem><para>Takes a mount
1045                                 propagation flag:
1046                                 <option>shared</option>,
1047                                 <option>slave</option> or
1048                                 <option>private</option>, which
1049                                 control whether the file system
1050                                 namespace set up for this unit's
1051                                 processes will receive or propagate
1052                                 new mounts. See
1053                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>2</manvolnum></citerefentry>
1054                                 for details. Default to
1055                                 <option>shared</option>.</para></listitem>
1056                         </varlistentry>
1057
1058                         <varlistentry>
1059                                 <term><varname>UtmpIdentifier=</varname></term>
1060
1061                                 <listitem><para>Takes a four
1062                                 character identifier string for an
1063                                 utmp/wtmp entry for this service. This
1064                                 should only be set for services such
1065                                 as <command>getty</command>
1066                                 implementations where utmp/wtmp
1067                                 entries must be created and cleared
1068                                 before and after execution. If the
1069                                 configured string is longer than four
1070                                 characters it is truncated and the
1071                                 terminal four characters are
1072                                 used. This setting interprets %I style
1073                                 string replacements. This setting is
1074                                 unset by default, i.e. no utmp/wtmp
1075                                 entries are created or cleaned up for
1076                                 this service.</para></listitem>
1077                         </varlistentry>
1078
1079                         <varlistentry>
1080                                 <term><varname>IgnoreSIGPIPE=</varname></term>
1081
1082                                 <listitem><para>Takes a boolean
1083                                 argument. If true causes SIGPIPE to be
1084                                 ignored in the executed
1085                                 process. Defaults to true, since
1086                                 SIGPIPE generally is useful only in
1087                                 shell pipelines.</para></listitem>
1088                         </varlistentry>
1089
1090                         <varlistentry>
1091                                 <term><varname>NoNewPrivileges=</varname></term>
1092
1093                                 <listitem><para>Takes a boolean
1094                                 argument. If true ensures that the
1095                                 service process and all its children
1096                                 can never gain new privileges. This
1097                                 option is more powerful than the respective
1098                                 secure bits flags (see above), as it
1099                                 also prohibits UID changes of any
1100                                 kind. This is the simplest, most
1101                                 effective way to ensure that a process
1102                                 and its children can never elevate
1103                                 privileges again.</para></listitem>
1104                         </varlistentry>
1105
1106                         <varlistentry>
1107                                 <term><varname>SystemCallFilter=</varname></term>
1108
1109                                 <listitem><para>Takes a space
1110                                 separated list of system call
1111                                 names. If this setting is used all
1112                                 system calls executed by the unit
1113                                 process except for the listed ones
1114                                 will result in immediate process
1115                                 termination with the SIGSYS signal
1116                                 (whitelisting). If the first character
1117                                 of the list is <literal>~</literal>
1118                                 the effect is inverted: only the
1119                                 listed system calls will result in
1120                                 immediate process termination
1121                                 (blacklisting). If this option is used
1122                                 <varname>NoNewPrivileges=yes</varname>
1123                                 is implied. This feature makes use of
1124                                 the Secure Computing Mode 2 interfaces
1125                                 of the kernel ('seccomp filtering')
1126                                 and is useful for enforcing a minimal
1127                                 sandboxing environment. Note that the
1128                                 <function>execve</function>,
1129                                 <function>rt_sigreturn</function>,
1130                                 <function>sigreturn</function>,
1131                                 <function>exit_group</function>,
1132                                 <function>exit</function> system calls
1133                                 are implicitly whitelisted and don't
1134                                 need to be listed
1135                                 explicitly.</para></listitem>
1136                         </varlistentry>
1137
1138                 </variablelist>
1139         </refsect1>
1140
1141         <refsect1>
1142                   <title>See Also</title>
1143                   <para>
1144                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1145                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1146                           <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1147                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1148                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1149                           <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1150                           <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1151                           <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1152                           <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1153                   </para>
1154         </refsect1>
1155
1156 </refentry>