man/systemd.exec.xml

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   9   Copyright 2010 Lennart Poettering
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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>systemd 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] resp. [Swap] section, 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
  93                                 processes.</para></listitem>
  94                         </varlistentry>
  95
  96                         <varlistentry>
  97                                 <term><varname>RootDirectory=</varname></term>
  98
  99                                 <listitem><para>Takes an absolute
 100                                 directory path. Sets the root
 101                                 directory for executed processes, with
 102                                 the
 103                                 <citerefentry><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 104                                 system call. If this is used it must
 105                                 be ensured that the process and all
 106                                 its auxiliary files are available in
 107                                 the <function>chroot()</function>
 108                                 jail.</para></listitem>
 109                         </varlistentry>
 110
 111                         <varlistentry>
 112                                 <term><varname>User=</varname></term>
 113                                 <term><varname>Group=</varname></term>
 114
 115                                 <listitem><para>Sets the Unix user
 116                                 resp. group the processes are executed
 117                                 as. Takes a single user resp. group
 118                                 name or ID as argument. If no group is
 119                                 set the default group of the user is
 120                                 chosen.</para></listitem>
 121                         </varlistentry>
 122
 123                         <varlistentry>
 124                                 <term><varname>SupplementaryGroups=</varname></term>
 125
 126                                 <listitem><para>Sets the supplementary
 127                                 Unix groups the processes are executed
 128                                 as. This takes a space separated list
 129                                 of group names or IDs. This option may
 130                                 be specified more than once in which
 131                                 case all listed groups are set as
 132                                 supplementary groups. This option does
 133                                 not override but extends the list of
 134                                 supplementary groups configured in the
 135                                 system group database for the
 136                                 user.</para></listitem>
 137                         </varlistentry>
 138
 139                         <varlistentry>
 140                                 <term><varname>Nice=</varname></term>
 141
 142                                 <listitem><para>Sets the default nice
 143                                 level (scheduling priority) for
 144                                 executed processes. Takes an integer
 145                                 between -20 (highest priority) and 19
 146                                 (lowest priority). See
 147                                 <citerefentry><refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 148                                 for details.</para></listitem>
 149                         </varlistentry>
 150
 151                         <varlistentry>
 152                                 <term><varname>OOMScoreAdjust=</varname></term>
 153
 154                                 <listitem><para>Sets the adjustment
 155                                 level for the Out-Of-Memory killer for
 156                                 executed processes. Takes an integer
 157                                 between -1000 (to disable OOM killing
 158                                 for this process) and 1000 (to make
 159                                 killing of this process under memory
 160                                 pressure very likely). See <ulink
 161                                 url="http://www.kernel.org/doc/Documentation/filesystems/proc.txt">proc.txt</ulink>
 162                                 for details.</para></listitem>
 163                         </varlistentry>
 164
 165                         <varlistentry>
 166                                 <term><varname>IOSchedulingClass=</varname></term>
 167
 168                                 <listitem><para>Sets the IO scheduling
 169                                 class for executed processes. Takes an
 170                                 integer between 0 and 3 or one of the
 171                                 strings <option>none</option>,
 172                                 <option>realtime</option>,
 173                                 <option>best-effort</option> or
 174                                 <option>idle</option>. See
 175                                 <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 176                                 for details.</para></listitem>
 177                         </varlistentry>
 178
 179                         <varlistentry>
 180                                 <term><varname>IOSchedulingPriority=</varname></term>
 181
 182                                 <listitem><para>Sets the IO scheduling
 183                                 priority for executed processes. Takes
 184                                 an integer between 0 (highest
 185                                 priority) and 7 (lowest priority). The
 186                                 available priorities depend on the
 187                                 selected IO scheduling class (see
 188                                 above). See
 189                                 <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 190                                 for details.</para></listitem>
 191                         </varlistentry>
 192
 193                         <varlistentry>
 194                                 <term><varname>CPUSchedulingPolicy=</varname></term>
 195
 196                                 <listitem><para>Sets the CPU
 197                                 scheduling policy for executed
 198                                 processes. Takes one of
 199                                 <option>other</option>,
 200                                 <option>batch</option>,
 201                                 <option>idle</option>,
 202                                 <option>fifo</option> or
 203                                 <option>rr</option>. See
 204                                 <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 205                                 for details.</para></listitem>
 206                         </varlistentry>
 207
 208                         <varlistentry>
 209                                 <term><varname>CPUSchedulingPriority=</varname></term>
 210
 211                                 <listitem><para>Sets the CPU
 212                                 scheduling priority for executed
 213                                 processes. Takes an integer between 1
 214                                 (lowest priority) and 99 (highest
 215                                 priority). The available priority
 216                                 range depends on the selected CPU
 217                                 scheduling policy (see above). See
 218                                 <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 219                                 for details.</para></listitem>
 220                         </varlistentry>
 221
 222                         <varlistentry>
 223                                 <term><varname>CPUSchedulingResetOnFork=</varname></term>
 224
 225                                 <listitem><para>Takes a boolean
 226                                 argument. If true elevated CPU
 227                                 scheduling priorities and policies
 228                                 will be reset when the executed
 229                                 processes fork, and can hence not leak
 230                                 into child processes. See
 231                                 <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 232                                 for details. Defaults to false.</para></listitem>
 233                         </varlistentry>
 234
 235                         <varlistentry>
 236                                 <term><varname>CPUAffinity=</varname></term>
 237
 238                                 <listitem><para>Controls the CPU
 239                                 affinity of the executed
 240                                 processes. Takes a space-separated
 241                                 list of CPU indexes. See
 242                                 <citerefentry><refentrytitle>sched_setaffinity</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 243                                 for details.</para></listitem>
 244                         </varlistentry>
 245
 246                         <varlistentry>
 247                                 <term><varname>UMask=</varname></term>
 248
 249                                 <listitem><para>Controls the file mode
 250                                 creation mask. Takes an access mode in
 251                                 octal notation. See
 252                                 <citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 253                                 for details. Defaults to
 254                                 0022.</para></listitem>
 255                         </varlistentry>
 256
 257                         <varlistentry>
 258                                 <term><varname>Environment=</varname></term>
 259
 260                                 <listitem><para>Sets environment
 261                                 variables for executed
 262                                 processes. Takes a space-separated
 263                                 list of variable assignments. This
 264                                 option may be specified more than once
 265                                 in which case all listed variables
 266                                 will be set. If the same variable is
 267                                 set twice the later setting will
 268                                 override the earlier setting. See
 269                                 <citerefentry><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 270                                 for details.</para></listitem>
 271                         </varlistentry>
 272                         <varlistentry>
 273                                 <term><varname>EnvironmentFile=</varname></term>
 274                                 <listitem><para>Similar to
 275                                 <varname>Environment=</varname> but
 276                                 reads the environment variables from a
 277                                 text file. The text file should
 278                                 contain new-line separated variable
 279                                 assignments. Empty lines and lines
 280                                 starting with ; or # will be ignored,
 281                                 which may be used for commenting. The
 282                                 argument passed should be an absolute
 283                                 file name, optionally prefixed with
 284                                 "-", which indicates that if the file
 285                                 does not exist it won't be read and no
 286                                 error or warning message is
 287                                 logged. The files listed with this
 288                                 directive will be read shortly before
 289                                 the process is executed. Settings from
 290                                 these files override settings made
 291                                 with
 292                                 <varname>Environment=</varname>. If
 293                                 the same variable is set twice from
 294                                 these files the files will be read in
 295                                 the order they are specified and the
 296                                 later setting will override the
 297                                 earlier setting. </para></listitem>
 298                         </varlistentry>
 299
 300                         <varlistentry>
 301                                 <term><varname>StandardInput=</varname></term>
 302                                 <listitem><para>Controls where file
 303                                 descriptor 0 (STDIN) of the executed
 304                                 processes is connected to. Takes one
 305                                 of <option>null</option>,
 306                                 <option>tty</option>,
 307                                 <option>tty-force</option>,
 308                                 <option>tty-fail</option> or
 309                                 <option>socket</option>. If
 310                                 <option>null</option> is selected
 311                                 standard input will be connected to
 312                                 <filename>/dev/null</filename>,
 313                                 i.e. all read attempts by the process
 314                                 will result in immediate EOF. If
 315                                 <option>tty</option> is selected
 316                                 standard input is connected to a TTY
 317                                 (as configured by
 318                                 <varname>TTYPath=</varname>, see
 319                                 below) and the executed process
 320                                 becomes the controlling process of the
 321                                 terminal. If the terminal is already
 322                                 being controlled by another process the
 323                                 executed process waits until the current
 324                                 controlling process releases the
 325                                 terminal.
 326                                 <option>tty-force</option>
 327                                 is similar to <option>tty</option>,
 328                                 but the executed process is forcefully
 329                                 and immediately made the controlling
 330                                 process of the terminal, potentially
 331                                 removing previous controlling
 332                                 processes from the
 333                                 terminal. <option>tty-fail</option> is
 334                                 similar to <option>tty</option> but if
 335                                 the terminal already has a controlling
 336                                 process start-up of the executed
 337                                 process fails.  The
 338                                 <option>socket</option> option is only
 339                                 valid in socket-activated services,
 340                                 and only when the socket configuration
 341                                 file (see
 342                                 <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 343                                 for details) specifies a single socket
 344                                 only. If this option is set standard
 345                                 input will be connected to the socket
 346                                 the service was activated from, which
 347                                 is primarily useful for compatibility
 348                                 with daemons designed for use with the
 349                                 traditional
 350                                 <citerefentry><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 351                                 daemon. This setting defaults to
 352                                 <option>null</option>.</para></listitem>
 353                         </varlistentry>
 354                         <varlistentry>
 355                                 <term><varname>StandardOutput=</varname></term>
 356                                 <listitem><para>Controls where file
 357                                 descriptor 1 (STDOUT) of the executed
 358                                 processes is connected to. Takes one
 359                                 of <option>inherit</option>,
 360                                 <option>null</option>,
 361                                 <option>tty</option>,
 362                                 <option>syslog</option>,
 363                                 <option>kmsg</option>,
 364                                 <option>kmsg+console</option>,
 365                                 <option>syslog+console</option> or
 366                                 <option>socket</option>. If set to
 367                                 <option>inherit</option> the file
 368                                 descriptor of standard input is
 369                                 duplicated for standard output. If set
 370                                 to <option>null</option> standard
 371                                 output will be connected to
 372                                 <filename>/dev/null</filename>,
 373                                 i.e. everything written to it will be
 374                                 lost. If set to <option>tty</option>
 375                                 standard output will be connected to a
 376                                 tty (as configured via
 377                                 <varname>TTYPath=</varname>, see
 378                                 below). If the TTY is used for output
 379                                 only the executed process will not
 380                                 become the controlling process of the
 381                                 terminal, and will not fail or wait
 382                                 for other processes to release the
 383                                 terminal. <option>syslog</option>
 384                                 connects standard output to the
 385                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 386                                 system logger. <option>kmsg</option>
 387                                 connects it with the kernel log buffer
 388                                 which is accessible via
 389                                 <citerefentry><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>. <option>syslog+console</option>
 390                                 and <option>kmsg+console</option> work
 391                                 similarly but copy the output to the
 392                                 system console as
 393                                 well. <option>socket</option> connects
 394                                 standard output to a socket from
 395                                 socket activation, semantics are
 396                                 similar to the respective option of
 397                                 <varname>StandardInput=</varname>.
 398                                 This setting defaults to
 399                                 <option>inherit</option>.</para></listitem>
 400                         </varlistentry>
 401                         <varlistentry>
 402                                 <term><varname>StandardError=</varname></term>
 403                                 <listitem><para>Controls where file
 404                                 descriptor 2 (STDERR) of the executed
 405                                 processes is connected to. The
 406                                 available options are identical to
 407                                 those of
 408                                 <varname>StandardOutput=</varname>,
 409                                 with one exception: if set to
 410                                 <option>inherit</option> the file
 411                                 descriptor used for standard output is
 412                                 duplicated for standard error. This
 413                                 setting defaults to
 414                                 <option>inherit</option>.</para></listitem>
 415                         </varlistentry>
 416                         <varlistentry>
 417                                 <term><varname>TTYPath=</varname></term>
 418                                 <listitem><para>Sets the terminal
 419                                 device node to use if standard input,
 420                                 output or stderr are connected to a
 421                                 TTY (see above). Defaults to
 422                                 <filename>/dev/console</filename>.</para></listitem>
 423                         </varlistentry>
 424                         <varlistentry>
 425                                 <term><varname>TTYReset=</varname></term>
 426                                 <listitem><para>Reset the terminal
 427                                 device specified with
 428                                 <varname>TTYPath=</varname> before and
 429                                 after execution. Defaults to
 430                                 <literal>no</literal>.</para></listitem>
 431                         </varlistentry>
 432                         <varlistentry>
 433                                 <term><varname>TTYVHangup=</varname></term>
 434                                 <listitem><para>Disconnect all clients
 435                                 which have opened the terminal device
 436                                 specified with
 437                                 <varname>TTYPath=</varname>
 438                                 before and after execution. Defaults
 439                                 to
 440                                 <literal>no</literal>.</para></listitem>
 441                         </varlistentry>
 442                         <varlistentry>
 443                                 <term><varname>TTYVTDisallocate=</varname></term>
 444                                 <listitem><para>If the the terminal
 445                                 device specified with
 446                                 <varname>TTYPath=</varname> is a
 447                                 virtual console terminal try to
 448                                 deallocate the TTY before and after
 449                                 execution. This ensures that the
 450                                 screen and scrollback buffer is
 451                                 cleared. Defaults to
 452                                 <literal>no</literal>.</para></listitem>
 453                         </varlistentry>
 454                         <varlistentry>
 455                                 <term><varname>SyslogIdentifier=</varname></term>
 456                                 <listitem><para>Sets the process name
 457                                 to prefix log lines sent to syslog or
 458                                 the kernel log buffer with. If not set
 459                                 defaults to the process name of the
 460                                 executed process. This option is only
 461                                 useful when
 462                                 <varname>StandardOutput=</varname> or
 463                                 <varname>StandardError=</varname> are
 464                                 set to <option>syslog</option> or
 465                                 <option>kmsg</option>.</para></listitem>
 466                         </varlistentry>
 467                         <varlistentry>
 468                                 <term><varname>SyslogFacility=</varname></term>
 469                                 <listitem><para>Sets the syslog
 470                                 facility to use when logging to
 471                                 syslog. One of <option>kern</option>,
 472                                 <option>user</option>,
 473                                 <option>mail</option>,
 474                                 <option>daemon</option>,
 475                                 <option>auth</option>,
 476                                 <option>syslog</option>,
 477                                 <option>lpr</option>,
 478                                 <option>news</option>,
 479                                 <option>uucp</option>,
 480                                 <option>cron</option>,
 481                                 <option>authpriv</option>,
 482                                 <option>ftp</option>,
 483                                 <option>local0</option>,
 484                                 <option>local1</option>,
 485                                 <option>local2</option>,
 486                                 <option>local3</option>,
 487                                 <option>local4</option>,
 488                                 <option>local5</option>,
 489                                 <option>local6</option> or
 490                                 <option>local7</option>. See
 491                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 492                                 for details. This option is only
 493                                 useful when
 494                                 <varname>StandardOutput=</varname> or
 495                                 <varname>StandardError=</varname> are
 496                                 set to <option>syslog</option>.
 497                                 Defaults to
 498                                 <option>daemon</option>.</para></listitem>
 499                         </varlistentry>
 500                         <varlistentry>
 501                                 <term><varname>SyslogLevel=</varname></term>
 502                                 <listitem><para>Default syslog level
 503                                 to use when logging to syslog or the
 504                                 kernel log buffer. One of
 505                                 <option>emerg</option>,
 506                                 <option>alert</option>,
 507                                 <option>crit</option>,
 508                                 <option>err</option>,
 509                                 <option>warning</option>,
 510                                 <option>notice</option>,
 511                                 <option>info</option>,
 512                                 <option>debug</option>. See
 513                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 514                                 for details. This option is only
 515                                 useful when
 516                                 <varname>StandardOutput=</varname> or
 517                                 <varname>StandardError=</varname> are
 518                                 set to <option>syslog</option> or
 519                                 <option>kmsg</option>. Note that
 520                                 individual lines output by the daemon
 521                                 might be prefixed with a different log
 522                                 level which can be used to override
 523                                 the default log level specified
 524                                 here. The interpretation of these
 525                                 prefixes may be disabled with
 526                                 <varname>SyslogLevelPrefix=</varname>,
 527                                 see below. For details see
 528                                 <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 529
 530                                 Defaults to
 531                                 <option>info</option>.</para></listitem>
 532                         </varlistentry>
 533
 534                         <varlistentry>
 535                                 <term><varname>SyslogLevelPrefix=</varname></term>
 536                                 <listitem><para>Takes a boolean
 537                                 argument. If true and
 538                                 <varname>StandardOutput=</varname> or
 539                                 <varname>StandardError=</varname> are
 540                                 set to <option>syslog</option> or
 541                                 <option>kmsg</option> log lines
 542                                 written by the executed process that
 543                                 are prefixed with a log level will be
 544                                 passed on to syslog with this log
 545                                 level set but the prefix removed. If
 546                                 set to false, the interpretation of
 547                                 these prefixes is disabled and the
 548                                 logged lines are passed on as-is. For
 549                                 details about this prefixing see
 550                                 <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 551                                 Defaults to true.</para></listitem>
 552                         </varlistentry>
 553
 554                         <varlistentry>
 555                                 <term><varname>TimerSlackNSec=</varname></term>
 556                                 <listitem><para>Sets the timer slack
 557                                 in nanoseconds for the executed
 558                                 processes. The timer slack controls the
 559                                 accuracy of wake-ups triggered by
 560                                 timers. See
 561                                 <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 562                                 for more information. Note that in
 563                                 contrast to most other time span
 564                                 definitions this parameter takes an
 565                                 integer value in nano-seconds and does
 566                                 not understand any other
 567                                 units.</para></listitem>
 568                         </varlistentry>
 569
 570                         <varlistentry>
 571                                 <term><varname>LimitCPU=</varname></term>
 572                                 <term><varname>LimitFSIZE=</varname></term>
 573                                 <term><varname>LimitDATA=</varname></term>
 574                                 <term><varname>LimitSTACK=</varname></term>
 575                                 <term><varname>LimitCORE=</varname></term>
 576                                 <term><varname>LimitRSS=</varname></term>
 577                                 <term><varname>LimitNOFILE=</varname></term>
 578                                 <term><varname>LimitAS=</varname></term>
 579                                 <term><varname>LimitNPROC=</varname></term>
 580                                 <term><varname>LimitMEMLOCK=</varname></term>
 581                                 <term><varname>LimitLOCKS=</varname></term>
 582                                 <term><varname>LimitSIGPENDING=</varname></term>
 583                                 <term><varname>LimitMSGQUEUE=</varname></term>
 584                                 <term><varname>LimitNICE=</varname></term>
 585                                 <term><varname>LimitRTPRIO=</varname></term>
 586                                 <term><varname>LimitRTTIME=</varname></term>
 587                                 <listitem><para>These settings control
 588                                 various resource limits for executed
 589                                 processes. See
 590                                 <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
 591                                 for details. Use the string
 592                                 <varname>infinity</varname> to
 593                                 configure no limit on a specific
 594                                 resource.</para></listitem>
 595                         </varlistentry>
 596
 597                         <varlistentry>
 598                                 <term><varname>PAMName=</varname></term>
 599                                 <listitem><para>Sets the PAM service
 600                                 name to set up a session as. If set
 601                                 the executed process will be
 602                                 registered as a PAM session under the
 603                                 specified service name. This is only
 604                                 useful in conjunction with the
 605                                 <varname>User=</varname> setting. If
 606                                 not set no PAM session will be opened
 607                                 for the executed processes. See
 608                                 <citerefentry><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 609                                 for details.</para></listitem>
 610                         </varlistentry>
 611
 612                         <varlistentry>
 613                                 <term><varname>TCPWrapName=</varname></term>
 614                                 <listitem><para>If this is a
 615                                 socket-activated service this sets the
 616                                 tcpwrap service name to check the
 617                                 permission for the current connection
 618                                 with. This is only useful in
 619                                 conjunction with socket-activated
 620                                 services, and stream sockets (TCP) in
 621                                 particular. It has no effect on other
 622                                 socket types (e.g. datagram/UDP) and on processes
 623                                 unrelated to socket-based
 624                                 activation. If the tcpwrap
 625                                 verification fails daemon start-up
 626                                 will fail and the connection is
 627                                 terminated. See
 628                                 <citerefentry><refentrytitle>tcpd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 629                                 for details.</para></listitem>
 630                         </varlistentry>
 631
 632                         <varlistentry>
 633                                 <term><varname>CapabilityBoundingSet=</varname></term>
 634
 635                                 <listitem><para>Controls which
 636                                 capabilities to include in the
 637                                 capability bounding set for the
 638                                 executed process. See
 639                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 640                                 for details. Takes a whitespace
 641                                 separated list of capability names as
 642                                 read by
 643                                 <citerefentry><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 644                                 Capabilities listed will be included
 645                                 in the bounding set, all others are
 646                                 removed. If the list of capabilities
 647                                 is prefixed with ~ all but the listed
 648                                 capabilities will be included, the
 649                                 effect of the assignment
 650                                 inverted. Note that this option does
 651                                 not actually set or unset any
 652                                 capabilities in the effective,
 653                                 permitted or inherited capability
 654                                 sets. That's what
 655                                 <varname>Capabilities=</varname> is
 656                                 for. If this option is not used the
 657                                 capability bounding set is not
 658                                 modified on process execution, hence
 659                                 no limits on the capabilities of the
 660                                 process are enforced.</para></listitem>
 661                         </varlistentry>
 662
 663                         <varlistentry>
 664                                 <term><varname>SecureBits=</varname></term>
 665                                 <listitem><para>Controls the secure
 666                                 bits set for the executed process. See
 667                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 668                                 for details. Takes a list of strings:
 669                                 <option>keep-caps</option>,
 670                                 <option>keep-caps-locked</option>,
 671                                 <option>no-setuid-fixup</option>,
 672                                 <option>no-setuid-fixup-locked</option>,
 673                                 <option>no-setuid-noroot</option> and/or
 674                                 <option>no-setuid-noroot-locked</option>.
 675                                 </para></listitem>
 676                         </varlistentry>
 677
 678                         <varlistentry>
 679                                 <term><varname>Capabilities=</varname></term>
 680                                 <listitem><para>Controls the
 681                                 <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 682                                 set for the executed process. Take a
 683                                 capability string describing the
 684                                 effective, permitted and inherited
 685                                 capability sets as documented in
 686                                 <citerefentry><refentrytitle>cap_from_text</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 687                                 Note that these capability sets are
 688                                 usually influenced by the capabilities
 689                                 attached to the executed file. Due to
 690                                 that
 691                                 <varname>CapabilityBoundingSet=</varname>
 692                                 is probably the much more useful
 693                                 setting.</para></listitem>
 694                         </varlistentry>
 695
 696                         <varlistentry>
 697                                 <term><varname>ControlGroup=</varname></term>
 698
 699                                 <listitem><para>Controls the control
 700                                 groups the executed processes shall be
 701                                 made members of. Takes a
 702                                 space-separated list of cgroup
 703                                 identifiers. A cgroup identifier has a
 704                                 format like
 705                                 <filename>cpu:/foo/bar</filename>,
 706                                 where "cpu" identifies the kernel
 707                                 control group controller used, and
 708                                 <filename>/foo/bar</filename> is the
 709                                 control group path. The controller
 710                                 name and ":" may be omitted in which
 711                                 case the named systemd control group
 712                                 hierarchy is implied. Alternatively,
 713                                 the path and ":" may be omitted, in
 714                                 which case the default control group
 715                                 path for this unit is implied. This
 716                                 option may be used to place executed
 717                                 processes in arbitrary groups in
 718                                 arbitrary hierarchies -- which can be
 719                                 configured externally with additional
 720                                 execution limits. By default systemd
 721                                 will place all executed processes in
 722                                 separate per-unit control groups
 723                                 (named after the unit) in the systemd
 724                                 named hierarchy. Since every process
 725                                 can be in one group per hierarchy only
 726                                 overriding the control group path in
 727                                 the named systemd hierarchy will
 728                                 disable automatic placement in the
 729                                 default group. This option is
 730                                 primarily intended to place executed
 731                                 processes in specific paths in
 732                                 specific kernel controller
 733                                 hierarchies. It is however not
 734                                 recommended to manipulate the service
 735                                 control group path in the systemd
 736                                 named hierarchy. For details about
 737                                 control groups see <ulink
 738                                 url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.</para></listitem>
 739                         </varlistentry>
 740
 741                         <varlistentry>
 742                                 <term><varname>ControlGroupModify=</varname></term>
 743                                 <listitem><para>Takes a boolean
 744                                 argument. If true, the control groups
 745                                 created for this unit will be owned by
 746                                 the user specified with
 747                                 <varname>User=</varname> (and the
 748                                 appropriate group), and he/she can create
 749                                 subgroups as well as add processes to
 750                                 the group.</para></listitem>
 751                         </varlistentry>
 752
 753                         <varlistentry>
 754                                 <term><varname>ControlGroupAttribute=</varname></term>
 755
 756                                 <listitem><para>Set a specific control
 757                                 group attribute for executed
 758                                 processes, and (if needed) add the the
 759                                 executed processes to a cgroup in the
 760                                 hierarchy of the controller the
 761                                 attribute belongs to. Takes two
 762                                 space-separated arguments: the
 763                                 attribute name (syntax is
 764                                 <literal>cpu.shares</literal> where
 765                                 <literal>cpu</literal> refers to a
 766                                 specific controller and
 767                                 <literal>shares</literal> to the
 768                                 attribute name), and the attribute
 769                                 value. Example:
 770                                 <literal>ControlGroupAttribute=cpu.shares
 771                                 512</literal>. If this option is used
 772                                 for an attribute that belongs to a
 773                                 kernel controller hierarchy the unit
 774                                 is not already configured to be added
 775                                 to (for example via the
 776                                 <literal>ControlGroup=</literal>
 777                                 option) then the unit will be added to
 778                                 the controller and the default unit
 779                                 cgroup path is implied. Thus, using
 780                                 <varname>ControlGroupAttribute=</varname>
 781                                 is in most case sufficient to make use
 782                                 of control group enforcements,
 783                                 explicit
 784                                 <varname>ControlGroup=</varname> are
 785                                 only necessary in case the implied
 786                                 default control group path for a
 787                                 service is not desirable. For details
 788                                 about control group attributes see
 789                                 <ulink
 790                                 url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>. This
 791                                 option may appear more than once, in
 792                                 order to set multiple control group
 793                                 attributes.</para></listitem>
 794                         </varlistentry>
 795
 796                         <varlistentry>
 797                                 <term><varname>CPUShares=</varname></term>
 798
 799                                 <listitem><para>Assign the specified
 800                                 overall CPU time shares to the processes executed. Takes
 801                                 an integer value. This controls the
 802                                 <literal>cpu.shares</literal> control
 803                                 group attribute. For details about
 804                                 this control group attribute see <ulink
 805                                 url="http://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para></listitem>
 806                         </varlistentry>
 807
 808                         <varlistentry>
 809                                 <term><varname>MemoryLimit=</varname></term>
 810                                 <term><varname>MemorySoftLimit=</varname></term>
 811
 812                                 <listitem><para>Limit the overall memory usage
 813                                 of the executed processes to a certain
 814                                 size. Takes a memory size in bytes. If
 815                                 the value is suffixed with K, M, G or
 816                                 T the specified memory size is parsed
 817                                 as Kilobytes, Megabytes, Gigabytes
 818                                 resp. Terabytes (to the base
 819                                 1024). This controls the
 820                                 <literal>memory.limit_in_bytes</literal>
 821                                 and
 822                                 <literal>memory.soft_limit_in_bytes</literal>
 823                                 control group attributes. For details
 824                                 about these control group attributes
 825                                 see <ulink
 826                                 url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para></listitem>
 827                         </varlistentry>
 828
 829                         <varlistentry>
 830                                 <term><varname>DeviceAllow=</varname></term>
 831                                 <term><varname>DeviceDeny=</varname></term>
 832
 833                                 <listitem><para>Control access to
 834                                 specific device nodes by the executed processes. Takes two
 835                                 space separated strings: a device node
 836                                 path (such as
 837                                 <filename>/dev/null</filename>)
 838                                 followed by a combination of r, w, m
 839                                 to control reading, writing resp.
 840                                 creating of the specific device node
 841                                 by the unit. This controls the
 842                                 <literal>devices.allow</literal>
 843                                 and
 844                                 <literal>devices.deny</literal>
 845                                 control group attributes. For details
 846                                 about these control group attributes
 847                                 see <ulink
 848                                 url="http://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para></listitem>
 849                         </varlistentry>
 850
 851                         <varlistentry>
 852                                 <term><varname>ReadWriteDirectories=</varname></term>
 853                                 <term><varname>ReadOnlyDirectories=</varname></term>
 854                                 <term><varname>InaccessibleDirectories=</varname></term>
 855
 856                                 <listitem><para>Sets up a new
 857                                 file-system name space for executed
 858                                 processes. These options may be used
 859                                 to limit access a process might have
 860                                 to the main file-system
 861                                 hierarchy. Each setting takes a
 862                                 space-separated list of absolute
 863                                 directory paths. Directories listed in
 864                                 <varname>ReadWriteDirectories=</varname>
 865                                 are accessible from within the
 866                                 namespace with the same access rights
 867                                 as from outside. Directories listed in
 868                                 <varname>ReadOnlyDirectories=</varname>
 869                                 are accessible for reading only,
 870                                 writing will be refused even if the
 871                                 usual file access controls would
 872                                 permit this. Directories listed in
 873                                 <varname>InaccessibleDirectories=</varname>
 874                                 will be made inaccessible for processes
 875                                 inside the namespace. Note that
 876                                 restricting access with these options
 877                                 does not extend to submounts of a
 878                                 directory. You must list submounts
 879                                 separately in these settings to
 880                                 ensure the same limited access. These
 881                                 options may be specified more than
 882                                 once in which case all directories
 883                                 listed will have limited access from
 884                                 within the
 885                                 namespace.</para></listitem>
 886                         </varlistentry>
 887
 888                         <varlistentry>
 889                                 <term><varname>PrivateTmp=</varname></term>
 890
 891                                 <listitem><para>Takes a boolean
 892                                 argument. If true sets up a new file
 893                                 system namespace for the executed
 894                                 processes and mounts a private
 895                                 <filename>/tmp</filename> directory
 896                                 inside it, that is not shared by
 897                                 processes outside of the
 898                                 namespace. This is useful to secure
 899                                 access to temporary files of the
 900                                 process, but makes sharing between
 901                                 processes via
 902                                 <filename>/tmp</filename>
 903                                 impossible. Defaults to
 904                                 false.</para></listitem>
 905                         </varlistentry>
 906
 907                         <varlistentry>
 908                                 <term><varname>PrivateNetwork=</varname></term>
 909
 910                                 <listitem><para>Takes a boolean
 911                                 argument. If true sets up a new
 912                                 network namespace for the executed
 913                                 processes and configures only the
 914                                 loopback network device
 915                                 <literal>lo</literal> inside it. No
 916                                 other network devices will be
 917                                 available to the executed process.
 918                                 This is useful to securely turn off
 919                                 network access by the executed
 920                                 process. Defaults to
 921                                 false.</para></listitem>
 922                         </varlistentry>
 923
 924                         <varlistentry>
 925                                 <term><varname>MountFlags=</varname></term>
 926
 927                                 <listitem><para>Takes a mount
 928                                 propagation flag:
 929                                 <option>shared</option>,
 930                                 <option>slave</option> or
 931                                 <option>private</option>, which
 932                                 control whether namespaces set up with
 933                                 <varname>ReadWriteDirectories=</varname>,
 934                                 <varname>ReadOnlyDirectories=</varname>
 935                                 and
 936                                 <varname>InaccessibleDirectories=</varname>
 937                                 receive or propagate new mounts
 938                                 from/to the main namespace. See
 939                                 <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 940                                 for details. Defaults to
 941                                 <option>shared</option>, i.e. the new
 942                                 namespace will both receive new mount
 943                                 points from the main namespace as well
 944                                 as propagate new mounts to
 945                                 it.</para></listitem>
 946                         </varlistentry>
 947
 948                         <varlistentry>
 949                                 <term><varname>UtmpIdentifier=</varname></term>
 950
 951                                 <listitem><para>Takes a a four
 952                                 character identifier string for an
 953                                 utmp/wtmp entry for this service. This
 954                                 should only be set for services such
 955                                 as <command>getty</command>
 956                                 implementations where utmp/wtmp
 957                                 entries must be created and cleared
 958                                 before and after execution. If the
 959                                 configured string is longer than four
 960                                 characters it is truncated and the
 961                                 terminal four characters are
 962                                 used. This setting interprets %I style
 963                                 string replacements. This setting is
 964                                 unset by default, i.e. no utmp/wtmp
 965                                 entries are created or cleaned up for
 966                                 this service.</para></listitem>
 967                         </varlistentry>
 968
 969                 </variablelist>
 970         </refsect1>
 971
 972         <refsect1>
 973                   <title>See Also</title>
 974                   <para>
 975                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 976                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 977                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 978                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 979                           <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 980                           <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 981                           <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 982                   </para>
 983         </refsect1>
 984
 985 </refentry>