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-<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
- "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-
-<!--
- This file is part of systemd.
-
- Copyright 2010 Lennart Poettering
-
- systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU Lesser General Public License as published by
- the Free Software Foundation; either version 2.1 of the License, or
- (at your option) any later version.
-
- systemd is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- Lesser General Public License for more details.
-
- You should have received a copy of the GNU Lesser General Public License
- along with systemd; If not, see <http://www.gnu.org/licenses/>.
--->
-
-<refentry id="systemd.exec">
- <refentryinfo>
- <title>systemd.exec</title>
- <productname>systemd</productname>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
- </refentryinfo>
-
- <refmeta>
- <refentrytitle>systemd.exec</refentrytitle>
- <manvolnum>5</manvolnum>
- </refmeta>
-
- <refnamediv>
- <refname>systemd.exec</refname>
- <refpurpose>Execution environment configuration</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <para><filename><replaceable>service</replaceable>.service</filename>,
- <filename><replaceable>socket</replaceable>.socket</filename>,
- <filename><replaceable>mount</replaceable>.mount</filename>,
- <filename><replaceable>swap</replaceable>.swap</filename></para>
- </refsynopsisdiv>
-
- <refsect1>
- <title>Description</title>
-
- <para>Unit configuration files for services, sockets, mount
- points, and swap devices share a subset of configuration options
- which define the execution environment of spawned
- processes.</para>
-
- <para>This man page lists the configuration options shared by
- these four unit types. See
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for the common options of all unit configuration files, and
- <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- and
- <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for more information on the specific unit configuration files. The
- execution specific configuration options are configured in the
- [Service], [Socket], [Mount], or [Swap] sections, depending on the
- unit type.</para>
- </refsect1>
-
- <refsect1>
- <title>Automatic Dependencies</title>
-
- <para>A few execution parameters result in additional, automatic
- dependencies to be added.</para>
-
- <para>Units with <varname>WorkingDirectory=</varname> or
- <varname>RootDirectory=</varname> set automatically gain
- dependencies of type <varname>Requires=</varname> and
- <varname>After=</varname> on all mount units required to access
- the specified paths. This is equivalent to having them listed
- explicitly in <varname>RequiresMountsFor=</varname>.</para>
-
- <para>Similar, units with <varname>PrivateTmp=</varname> enabled
- automatically get mount unit dependencies for all mounts
- required to access <filename>/tmp</filename> and
- <filename>/var/tmp</filename>.</para>
-
- <para>Units whose standard output or error output is connected to <option>journal</option>, <option>syslog</option>
- or <option>kmsg</option> (or their combinations with console output, see below) automatically acquire dependencies
- of type <varname>After=</varname> on <filename>systemd-journald.socket</filename>.</para>
- </refsect1>
-
- <refsect1>
- <title>Options</title>
-
- <variablelist class='unit-directives'>
-
- <varlistentry>
- <term><varname>WorkingDirectory=</varname></term>
-
- <listitem><para>Takes an absolute directory path, or the
- special value <literal>~</literal>. Sets the working directory
- for executed processes. If set to <literal>~</literal>, the
- home directory of the user specified in
- <varname>User=</varname> is used. If not set, defaults to the
- root directory when systemd is running as a system instance
- and the respective user's home directory if run as user. If
- the setting is prefixed with the <literal>-</literal>
- character, a missing working directory is not considered
- fatal. Note that setting this parameter might result in
- additional dependencies to be added to the unit (see
- above).</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>RootDirectory=</varname></term>
-
- <listitem><para>Takes an absolute directory path. Sets the
- root directory for executed processes, with the <citerefentry
- project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- system call. If this is used, it must be ensured that the
- process binary and all its auxiliary files are available in
- the <function>chroot()</function> jail. Note that setting this
- parameter might result in additional dependencies to be added
- to the unit (see above).</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>User=</varname></term>
- <term><varname>Group=</varname></term>
-
- <listitem><para>Sets the Unix user or group that the processes
- are executed as, respectively. Takes a single user or group
- name or ID as argument. If no group is set, the default group
- of the user is chosen.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SupplementaryGroups=</varname></term>
-
- <listitem><para>Sets the supplementary Unix groups the
- processes are executed as. This takes a space-separated list
- of group names or IDs. This option may be specified more than
- once, in which case all listed groups are set as supplementary
- groups. When the empty string is assigned, the list of
- supplementary groups is reset, and all assignments prior to
- this one will have no effect. In any way, this option does not
- override, but extends the list of supplementary groups
- configured in the system group database for the
- user.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>Nice=</varname></term>
-
- <listitem><para>Sets the default nice level (scheduling
- priority) for executed processes. Takes an integer between -20
- (highest priority) and 19 (lowest priority). See
- <citerefentry><refentrytitle>setpriority</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>OOMScoreAdjust=</varname></term>
-
- <listitem><para>Sets the adjustment level for the
- Out-Of-Memory killer for executed processes. Takes an integer
- between -1000 (to disable OOM killing for this process) and
- 1000 (to make killing of this process under memory pressure
- very likely). See <ulink
- url="https://www.kernel.org/doc/Documentation/filesystems/proc.txt">proc.txt</ulink>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>IOSchedulingClass=</varname></term>
-
- <listitem><para>Sets the I/O scheduling class for executed
- processes. Takes an integer between 0 and 3 or one of the
- strings <option>none</option>, <option>realtime</option>,
- <option>best-effort</option> or <option>idle</option>. See
- <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>IOSchedulingPriority=</varname></term>
-
- <listitem><para>Sets the I/O scheduling priority for executed
- processes. Takes an integer between 0 (highest priority) and 7
- (lowest priority). The available priorities depend on the
- selected I/O scheduling class (see above). See
- <citerefentry><refentrytitle>ioprio_set</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>CPUSchedulingPolicy=</varname></term>
-
- <listitem><para>Sets the CPU scheduling policy for executed
- processes. Takes one of
- <option>other</option>,
- <option>batch</option>,
- <option>idle</option>,
- <option>fifo</option> or
- <option>rr</option>. See
- <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>CPUSchedulingPriority=</varname></term>
-
- <listitem><para>Sets the CPU scheduling priority for executed
- processes. The available priority range depends on the
- selected CPU scheduling policy (see above). For real-time
- scheduling policies an integer between 1 (lowest priority) and
- 99 (highest priority) can be used. See
- <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details. </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>CPUSchedulingResetOnFork=</varname></term>
-
- <listitem><para>Takes a boolean argument. If true, elevated
- CPU scheduling priorities and policies will be reset when the
- executed processes fork, and can hence not leak into child
- processes. See
- <citerefentry><refentrytitle>sched_setscheduler</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details. Defaults to false.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>CPUAffinity=</varname></term>
-
- <listitem><para>Controls the CPU affinity of the executed
- processes. Takes a list of CPU indices or ranges separated by
- either whitespace or commas. CPU ranges are specified by the
- lower and upper CPU indices separated by a dash.
- This option may be specified more than once, in which case the
- specified CPU affinity masks are merged. If the empty string
- is assigned, the mask is reset, all assignments prior to this
- will have no effect. See
- <citerefentry><refentrytitle>sched_setaffinity</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>UMask=</varname></term>
-
- <listitem><para>Controls the file mode creation mask. Takes an
- access mode in octal notation. See
- <citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details. Defaults to 0022.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>Environment=</varname></term>
-
- <listitem><para>Sets environment variables for executed
- processes. Takes a space-separated list of variable
- assignments. This option may be specified more than once, in
- which case all listed variables will be set. If the same
- variable is set twice, the later setting will override the
- earlier setting. If the empty string is assigned to this
- option, the list of environment variables is reset, all prior
- assignments have no effect. Variable expansion is not
- performed inside the strings, however, specifier expansion is
- possible. The $ character has no special meaning. If you need
- to assign a value containing spaces to a variable, use double
- quotes (") for the assignment.</para>
-
- <para>Example:
- <programlisting>Environment="VAR1=word1 word2" VAR2=word3 "VAR3=$word 5 6"</programlisting>
- gives three variables <literal>VAR1</literal>,
- <literal>VAR2</literal>, <literal>VAR3</literal>
- with the values <literal>word1 word2</literal>,
- <literal>word3</literal>, <literal>$word 5 6</literal>.
- </para>
-
- <para>
- See
- <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details about environment variables.</para></listitem>
- </varlistentry>
- <varlistentry>
- <term><varname>EnvironmentFile=</varname></term>
- <listitem><para>Similar to <varname>Environment=</varname> but
- reads the environment variables from a text file. The text
- file should contain new-line-separated variable assignments.
- Empty lines, lines without an <literal>=</literal> separator,
- or lines starting with ; or # will be ignored,
- which may be used for commenting. A line ending with a
- backslash will be concatenated with the following one,
- allowing multiline variable definitions. The parser strips
- leading and trailing whitespace from the values of
- assignments, unless you use double quotes (").</para>
-
- <para>The argument passed should be an absolute filename or
- wildcard expression, optionally prefixed with
- <literal>-</literal>, which indicates that if the file does
- not exist, it will not be read and no error or warning message
- is logged. This option may be specified more than once in
- which case all specified files are read. If the empty string
- is assigned to this option, the list of file to read is reset,
- all prior assignments have no effect.</para>
-
- <para>The files listed with this directive will be read
- shortly before the process is executed (more specifically,
- after all processes from a previous unit state terminated.
- This means you can generate these files in one unit state, and
- read it with this option in the next).</para>
-
- <para>Settings from these
- files override settings made with
- <varname>Environment=</varname>. If the same variable is set
- twice from these files, the files will be read in the order
- they are specified and the later setting will override the
- earlier setting.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>PassEnvironment=</varname></term>
-
- <listitem><para>Pass environment variables from the systemd system
- manager to executed processes. Takes a space-separated list of variable
- names. This option may be specified more than once, in which case all
- listed variables will be set. If the empty string is assigned to this
- option, the list of environment variables is reset, all prior
- assignments have no effect. Variables that are not set in the system
- manager will not be passed and will be silently ignored.</para>
-
- <para>Variables passed from this setting are overridden by those passed
- from <varname>Environment=</varname> or
- <varname>EnvironmentFile=</varname>.</para>
-
- <para>Example:
- <programlisting>PassEnvironment=VAR1 VAR2 VAR3</programlisting>
- passes three variables <literal>VAR1</literal>,
- <literal>VAR2</literal>, <literal>VAR3</literal>
- with the values set for those variables in PID1.</para>
-
- <para>
- See
- <citerefentry project='man-pages'><refentrytitle>environ</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details about environment variables.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>StandardInput=</varname></term>
- <listitem><para>Controls where file descriptor 0 (STDIN) of
- the executed processes is connected to. Takes one of
- <option>null</option>,
- <option>tty</option>,
- <option>tty-force</option>,
- <option>tty-fail</option> or
- <option>socket</option>.</para>
-
- <para>If <option>null</option> is selected, standard input
- will be connected to <filename>/dev/null</filename>, i.e. all
- read attempts by the process will result in immediate
- EOF.</para>
-
- <para>If <option>tty</option> is selected, standard input is
- connected to a TTY (as configured by
- <varname>TTYPath=</varname>, see below) and the executed
- process becomes the controlling process of the terminal. If
- the terminal is already being controlled by another process,
- the executed process waits until the current controlling
- process releases the terminal.</para>
-
- <para><option>tty-force</option> is similar to
- <option>tty</option>, but the executed process is forcefully
- and immediately made the controlling process of the terminal,
- potentially removing previous controlling processes from the
- terminal.</para>
-
- <para><option>tty-fail</option> is similar to
- <option>tty</option> but if the terminal already has a
- controlling process start-up of the executed process
- fails.</para>
-
- <para>The <option>socket</option> option is only valid in
- socket-activated services, and only when the socket
- configuration file (see
- <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for details) specifies a single socket only. If this option is
- set, standard input will be connected to the socket the
- service was activated from, which is primarily useful for
- compatibility with daemons designed for use with the
- traditional
- <citerefentry project='freebsd'><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- daemon.</para>
-
- <para>This setting defaults to
- <option>null</option>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>StandardOutput=</varname></term>
- <listitem><para>Controls where file descriptor 1 (STDOUT) of
- the executed processes is connected to. Takes one of
- <option>inherit</option>,
- <option>null</option>,
- <option>tty</option>,
- <option>journal</option>,
- <option>syslog</option>,
- <option>kmsg</option>,
- <option>journal+console</option>,
- <option>syslog+console</option>,
- <option>kmsg+console</option> or
- <option>socket</option>.</para>
-
- <para><option>inherit</option> duplicates the file descriptor
- of standard input for standard output.</para>
-
- <para><option>null</option> connects standard output to
- <filename>/dev/null</filename>, i.e. everything written to it
- will be lost.</para>
-
- <para><option>tty</option> connects standard output to a tty
- (as configured via <varname>TTYPath=</varname>, see below). If
- the TTY is used for output only, the executed process will not
- become the controlling process of the terminal, and will not
- fail or wait for other processes to release the
- terminal.</para>
-
- <para><option>journal</option> connects standard output with
- the journal which is accessible via
- <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
- Note that everything that is written to syslog or kmsg (see
- below) is implicitly stored in the journal as well, the
- specific two options listed below are hence supersets of this
- one.</para>
-
- <para><option>syslog</option> connects standard output to the
- <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- system syslog service, in addition to the journal. Note that
- the journal daemon is usually configured to forward everything
- it receives to syslog anyway, in which case this option is no
- different from <option>journal</option>.</para>
-
- <para><option>kmsg</option> connects standard output with the
- kernel log buffer which is accessible via
- <citerefentry project='man-pages'><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- in addition to the journal. The journal daemon might be
- configured to send all logs to kmsg anyway, in which case this
- option is no different from <option>journal</option>.</para>
-
- <para><option>journal+console</option>,
- <option>syslog+console</option> and
- <option>kmsg+console</option> work in a similar way as the
- three options above but copy the output to the system console
- as well.</para>
-
- <para><option>socket</option> connects standard output to a
- socket acquired via socket activation. The semantics are
- similar to the same option of
- <varname>StandardInput=</varname>.</para>
-
- <para>If the standard output (or error output, see below) of a unit is connected to the journal, syslog or the
- kernel log buffer, the unit will implicitly gain a dependency of type <varname>After=</varname> on
- <filename>systemd-journald.socket</filename> (also see the automatic dependencies section above).</para>
-
- <para>This setting defaults to the value set with
- <option>DefaultStandardOutput=</option> in
- <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- which defaults to <option>journal</option>. Note that setting
- this parameter might result in additional dependencies to be
- added to the unit (see above).</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>StandardError=</varname></term>
- <listitem><para>Controls where file descriptor 2 (STDERR) of
- the executed processes is connected to. The available options
- are identical to those of <varname>StandardOutput=</varname>,
- with one exception: if set to <option>inherit</option> the
- file descriptor used for standard output is duplicated for
- standard error. This setting defaults to the value set with
- <option>DefaultStandardError=</option> in
- <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- which defaults to <option>inherit</option>. Note that setting
- this parameter might result in additional dependencies to be
- added to the unit (see above).</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>TTYPath=</varname></term>
- <listitem><para>Sets the terminal device node to use if
- standard input, output, or error are connected to a TTY (see
- above). Defaults to
- <filename>/dev/console</filename>.</para></listitem>
- </varlistentry>
- <varlistentry>
- <term><varname>TTYReset=</varname></term>
- <listitem><para>Reset the terminal device specified with
- <varname>TTYPath=</varname> before and after execution.
- Defaults to <literal>no</literal>.</para></listitem>
- </varlistentry>
- <varlistentry>
- <term><varname>TTYVHangup=</varname></term>
- <listitem><para>Disconnect all clients which have opened the
- terminal device specified with <varname>TTYPath=</varname>
- before and after execution. Defaults to
- <literal>no</literal>.</para></listitem>
- </varlistentry>
- <varlistentry>
- <term><varname>TTYVTDisallocate=</varname></term>
- <listitem><para>If the terminal device specified with
- <varname>TTYPath=</varname> is a virtual console terminal, try
- to deallocate the TTY before and after execution. This ensures
- that the screen and scrollback buffer is cleared. Defaults to
- <literal>no</literal>.</para></listitem>
- </varlistentry>
- <varlistentry>
- <term><varname>SyslogIdentifier=</varname></term>
- <listitem><para>Sets the process name to prefix log lines sent
- to the logging system or the kernel log buffer with. If not
- set, defaults to the process name of the executed process.
- This option is only useful when
- <varname>StandardOutput=</varname> or
- <varname>StandardError=</varname> are set to
- <option>syslog</option>, <option>journal</option> or
- <option>kmsg</option> (or to the same settings in combination
- with <option>+console</option>).</para></listitem>
- </varlistentry>
- <varlistentry>
- <term><varname>SyslogFacility=</varname></term>
- <listitem><para>Sets the syslog facility to use when logging
- to syslog. One of <option>kern</option>,
- <option>user</option>, <option>mail</option>,
- <option>daemon</option>, <option>auth</option>,
- <option>syslog</option>, <option>lpr</option>,
- <option>news</option>, <option>uucp</option>,
- <option>cron</option>, <option>authpriv</option>,
- <option>ftp</option>, <option>local0</option>,
- <option>local1</option>, <option>local2</option>,
- <option>local3</option>, <option>local4</option>,
- <option>local5</option>, <option>local6</option> or
- <option>local7</option>. See
- <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for details. This option is only useful when
- <varname>StandardOutput=</varname> or
- <varname>StandardError=</varname> are set to
- <option>syslog</option>. Defaults to
- <option>daemon</option>.</para></listitem>
- </varlistentry>
- <varlistentry>
- <term><varname>SyslogLevel=</varname></term>
- <listitem><para>The default syslog level to use when logging to
- syslog or the kernel log buffer. One of
- <option>emerg</option>,
- <option>alert</option>,
- <option>crit</option>,
- <option>err</option>,
- <option>warning</option>,
- <option>notice</option>,
- <option>info</option>,
- <option>debug</option>. See
- <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for details. This option is only useful when
- <varname>StandardOutput=</varname> or
- <varname>StandardError=</varname> are set to
- <option>syslog</option> or <option>kmsg</option>. Note that
- individual lines output by the daemon might be prefixed with a
- different log level which can be used to override the default
- log level specified here. The interpretation of these prefixes
- may be disabled with <varname>SyslogLevelPrefix=</varname>,
- see below. For details, see
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
-
- Defaults to
- <option>info</option>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SyslogLevelPrefix=</varname></term>
- <listitem><para>Takes a boolean argument. If true and
- <varname>StandardOutput=</varname> or
- <varname>StandardError=</varname> are set to
- <option>syslog</option>, <option>kmsg</option> or
- <option>journal</option>, log lines written by the executed
- process that are prefixed with a log level will be passed on
- to syslog with this log level set but the prefix removed. If
- set to false, the interpretation of these prefixes is disabled
- and the logged lines are passed on as-is. For details about
- this prefixing see
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- Defaults to true.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>TimerSlackNSec=</varname></term>
- <listitem><para>Sets the timer slack in nanoseconds for the
- executed processes. The timer slack controls the accuracy of
- wake-ups triggered by timers. See
- <citerefentry><refentrytitle>prctl</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for more information. Note that in contrast to most other time
- span definitions this parameter takes an integer value in
- nano-seconds if no unit is specified. The usual time units are
- understood too.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>LimitCPU=</varname></term>
- <term><varname>LimitFSIZE=</varname></term>
- <term><varname>LimitDATA=</varname></term>
- <term><varname>LimitSTACK=</varname></term>
- <term><varname>LimitCORE=</varname></term>
- <term><varname>LimitRSS=</varname></term>
- <term><varname>LimitNOFILE=</varname></term>
- <term><varname>LimitAS=</varname></term>
- <term><varname>LimitNPROC=</varname></term>
- <term><varname>LimitMEMLOCK=</varname></term>
- <term><varname>LimitLOCKS=</varname></term>
- <term><varname>LimitSIGPENDING=</varname></term>
- <term><varname>LimitMSGQUEUE=</varname></term>
- <term><varname>LimitNICE=</varname></term>
- <term><varname>LimitRTPRIO=</varname></term>
- <term><varname>LimitRTTIME=</varname></term>
- <listitem><para>Set soft and hard limits on various resources for executed processes. See
- <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry> for details on
- the resource limit concept. Resource limits may be specified in two formats: either as single value to set a
- specific soft and hard limit to the same value, or as colon-separated pair <option>soft:hard</option> to set
- both limits individually (e.g. <literal>LimitAS=4G:16G</literal>). Use the string <varname>infinity</varname>
- to configure no limit on a specific resource. The multiplicative suffixes K, M, G, T, P and E (to the base
- 1024) may be used for resource limits measured in bytes (e.g. LimitAS=16G). For the limits referring to time
- values, the usual time units ms, s, min, h and so on may be used (see
- <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
- details). Note that if no time unit is specified for <varname>LimitCPU=</varname> the default unit of seconds
- is implied, while for <varname>LimitRTTIME=</varname> the default unit of microseconds is implied. Also, note
- that the effective granularity of the limits might influence their enforcement. For example, time limits
- specified for <varname>LimitCPU=</varname> will be rounded up implicitly to multiples of 1s. For
- <varname>LimitNICE=</varname> the value may be specified in two syntaxes: if prefixed with <literal>+</literal>
- or <literal>-</literal>, the value is understood as regular Linux nice value in the range -20..19. If not
- prefixed like this the value is understood as raw resource limit parameter in the range 0..40 (with 0 being
- equivalent to 1).</para>
-
- <para>Note that most process resource limits configured with
- these options are per-process, and processes may fork in order
- to acquire a new set of resources that are accounted
- independently of the original process, and may thus escape
- limits set. Also note that <varname>LimitRSS=</varname> is not
- implemented on Linux, and setting it has no effect. Often it
- is advisable to prefer the resource controls listed in
- <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- over these per-process limits, as they apply to services as a
- whole, may be altered dynamically at runtime, and are
- generally more expressive. For example,
- <varname>MemoryLimit=</varname> is a more powerful (and
- working) replacement for <varname>LimitRSS=</varname>.</para>
-
- <table>
- <title>Limit directives and their equivalent with ulimit</title>
-
- <tgroup cols='3'>
- <colspec colname='directive' />
- <colspec colname='equivalent' />
- <colspec colname='unit' />
- <thead>
- <row>
- <entry>Directive</entry>
- <entry>ulimit equivalent</entry>
- <entry>Unit</entry>
- </row>
- </thead>
- <tbody>
- <row>
- <entry>LimitCPU=</entry>
- <entry>ulimit -t</entry>
- <entry>Seconds</entry>
- </row>
- <row>
- <entry>LimitFSIZE=</entry>
- <entry>ulimit -f</entry>
- <entry>Bytes</entry>
- </row>
- <row>
- <entry>LimitDATA=</entry>
- <entry>ulimit -d</entry>
- <entry>Bytes</entry>
- </row>
- <row>
- <entry>LimitSTACK=</entry>
- <entry>ulimit -s</entry>
- <entry>Bytes</entry>
- </row>
- <row>
- <entry>LimitCORE=</entry>
- <entry>ulimit -c</entry>
- <entry>Bytes</entry>
- </row>
- <row>
- <entry>LimitRSS=</entry>
- <entry>ulimit -m</entry>
- <entry>Bytes</entry>
- </row>
- <row>
- <entry>LimitNOFILE=</entry>
- <entry>ulimit -n</entry>
- <entry>Number of File Descriptors</entry>
- </row>
- <row>
- <entry>LimitAS=</entry>
- <entry>ulimit -v</entry>
- <entry>Bytes</entry>
- </row>
- <row>
- <entry>LimitNPROC=</entry>
- <entry>ulimit -u</entry>
- <entry>Number of Processes</entry>
- </row>
- <row>
- <entry>LimitMEMLOCK=</entry>
- <entry>ulimit -l</entry>
- <entry>Bytes</entry>
- </row>
- <row>
- <entry>LimitLOCKS=</entry>
- <entry>ulimit -x</entry>
- <entry>Number of Locks</entry>
- </row>
- <row>
- <entry>LimitSIGPENDING=</entry>
- <entry>ulimit -i</entry>
- <entry>Number of Queued Signals</entry>
- </row>
- <row>
- <entry>LimitMSGQUEUE=</entry>
- <entry>ulimit -q</entry>
- <entry>Bytes</entry>
- </row>
- <row>
- <entry>LimitNICE=</entry>
- <entry>ulimit -e</entry>
- <entry>Nice Level</entry>
- </row>
- <row>
- <entry>LimitRTPRIO=</entry>
- <entry>ulimit -r</entry>
- <entry>Realtime Priority</entry>
- </row>
- <row>
- <entry>LimitRTTIME=</entry>
- <entry>No equivalent</entry>
- <entry>Microseconds</entry>
- </row>
- </tbody>
- </tgroup>
- </table></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>PAMName=</varname></term>
- <listitem><para>Sets the PAM service name to set up a session
- as. If set, the executed process will be registered as a PAM
- session under the specified service name. This is only useful
- in conjunction with the <varname>User=</varname> setting. If
- not set, no PAM session will be opened for the executed
- processes. See
- <citerefentry project='man-pages'><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>CapabilityBoundingSet=</varname></term>
-
- <listitem><para>Controls which capabilities to include in the capability bounding set for the executed
- process. See <citerefentry
- project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
- details. Takes a whitespace-separated list of capability names as read by <citerefentry
- project='mankier'><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- e.g. <constant>CAP_SYS_ADMIN</constant>, <constant>CAP_DAC_OVERRIDE</constant>,
- <constant>CAP_SYS_PTRACE</constant>. Capabilities listed will be included in the bounding set, all others are
- removed. If the list of capabilities is prefixed with <literal>~</literal>, all but the listed capabilities
- will be included, the effect of the assignment inverted. Note that this option also affects the respective
- capabilities in the effective, permitted and inheritable capability sets. If this option is not used, the
- capability bounding set is not modified on process execution, hence no limits on the capabilities of the
- process are enforced. This option may appear more than once, in which case the bounding sets are merged. If the
- empty string is assigned to this option, the bounding set is reset to the empty capability set, and all prior
- settings have no effect. If set to <literal>~</literal> (without any further argument), the bounding set is
- reset to the full set of available capabilities, also undoing any previous settings.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>AmbientCapabilities=</varname></term>
-
- <listitem><para>Controls which capabilities to include in the
- ambient capability set for the executed process. Takes a
- whitespace-separated list of capability names as read by
- <citerefentry project='mankier'><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- e.g. <constant>CAP_SYS_ADMIN</constant>,
- <constant>CAP_DAC_OVERRIDE</constant>,
- <constant>CAP_SYS_PTRACE</constant>. This option may appear more than
- once in which case the ambient capability sets are merged.
- If the list of capabilities is prefixed with <literal>~</literal>, all
- but the listed capabilities will be included, the effect of the
- assignment inverted. If the empty string is
- assigned to this option, the ambient capability set is reset to
- the empty capability set, and all prior settings have no effect.
- If set to <literal>~</literal> (without any further argument), the
- ambient capability set is reset to the full set of available
- capabilities, also undoing any previous settings. Note that adding
- capabilities to ambient capability set adds them to the process's
- inherited capability set.
- </para><para>
- Ambient capability sets are useful if you want to execute a process
- as a non-privileged user but still want to give it some capabilities.
- Note that in this case option <constant>keep-caps</constant> is
- automatically added to <varname>SecureBits=</varname> to retain the
- capabilities over the user change.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SecureBits=</varname></term>
- <listitem><para>Controls the secure bits set for the executed
- process. Takes a space-separated combination of options from
- the following list:
- <option>keep-caps</option>,
- <option>keep-caps-locked</option>,
- <option>no-setuid-fixup</option>,
- <option>no-setuid-fixup-locked</option>,
- <option>noroot</option>, and
- <option>noroot-locked</option>.
- This option may appear more than once, in which case the secure
- bits are ORed. If the empty string is assigned to this option,
- the bits are reset to 0. See
- <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>ReadWriteDirectories=</varname></term>
- <term><varname>ReadOnlyDirectories=</varname></term>
- <term><varname>InaccessibleDirectories=</varname></term>
-
- <listitem><para>Sets up a new file system namespace for
- executed processes. These options may be used to limit access
- a process might have to the main file system hierarchy. Each
- setting takes a space-separated list of absolute directory
- paths. Directories listed in
- <varname>ReadWriteDirectories=</varname> are accessible from
- within the namespace with the same access rights as from
- outside. Directories listed in
- <varname>ReadOnlyDirectories=</varname> are accessible for
- reading only, writing will be refused even if the usual file
- access controls would permit this. Directories listed in
- <varname>InaccessibleDirectories=</varname> will be made
- inaccessible for processes inside the namespace, and may not
- countain any other mountpoints, including those specified by
- <varname>ReadWriteDirectories=</varname> or
- <varname>ReadOnlyDirectories=</varname>.
- Note that restricting access with these options does not extend
- to submounts of a directory that are created later on. These
- options may be specified more than once, in which case all
- directories listed will have limited access from within the
- namespace. If the empty string is assigned to this option, the
- specific list is reset, and all prior assignments have no
- effect.</para>
- <para>Paths in
- <varname>ReadOnlyDirectories=</varname>
- and
- <varname>InaccessibleDirectories=</varname>
- may be prefixed with
- <literal>-</literal>, in which case
- they will be ignored when they do not
- exist. Note that using this
- setting will disconnect propagation of
- mounts from the service to the host
- (propagation in the opposite direction
- continues to work). This means that
- this setting may not be used for
- services which shall be able to
- install mount points in the main mount
- namespace.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>PrivateTmp=</varname></term>
-
- <listitem><para>Takes a boolean argument. If true, sets up a
- new file system namespace for the executed processes and
- mounts private <filename>/tmp</filename> and
- <filename>/var/tmp</filename> directories inside it that is
- not shared by processes outside of the namespace. This is
- useful to secure access to temporary files of the process, but
- makes sharing between processes via <filename>/tmp</filename>
- or <filename>/var/tmp</filename> impossible. If this is
- enabled, all temporary files created by a service in these
- directories will be removed after the service is stopped.
- Defaults to false. It is possible to run two or more units
- within the same private <filename>/tmp</filename> and
- <filename>/var/tmp</filename> namespace by using the
- <varname>JoinsNamespaceOf=</varname> directive, see
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for details. Note that using this setting will disconnect
- propagation of mounts from the service to the host
- (propagation in the opposite direction continues to work).
- This means that this setting may not be used for services
- which shall be able to install mount points in the main mount
- namespace.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>PrivateDevices=</varname></term>
-
- <listitem><para>Takes a boolean argument. If true, sets up a
- new /dev namespace for the executed processes and only adds
- API pseudo devices such as <filename>/dev/null</filename>,
- <filename>/dev/zero</filename> or
- <filename>/dev/random</filename> (as well as the pseudo TTY
- subsystem) to it, but no physical devices such as
- <filename>/dev/sda</filename>. This is useful to securely turn
- off physical device access by the executed process. Defaults
- to false. Enabling this option will also remove
- <constant>CAP_MKNOD</constant> from the capability bounding
- set for the unit (see above), and set
- <varname>DevicePolicy=closed</varname> (see
- <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for details). Note that using this setting will disconnect
- propagation of mounts from the service to the host
- (propagation in the opposite direction continues to work).
- This means that this setting may not be used for services
- which shall be able to install mount points in the main mount
- namespace. The /dev namespace will be mounted read-only and 'noexec'.
- The latter may break old programs which try to set up executable
- memory by using <citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- of <filename>/dev/zero</filename> instead of using <constant>MAP_ANON</constant>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>PrivateNetwork=</varname></term>
-
- <listitem><para>Takes a boolean argument. If true, sets up a
- new network namespace for the executed processes and
- configures only the loopback network device
- <literal>lo</literal> inside it. No other network devices will
- be available to the executed process. This is useful to
- securely turn off network access by the executed process.
- Defaults to false. It is possible to run two or more units
- within the same private network namespace by using the
- <varname>JoinsNamespaceOf=</varname> directive, see
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- for details. Note that this option will disconnect all socket
- families from the host, this includes AF_NETLINK and AF_UNIX.
- The latter has the effect that AF_UNIX sockets in the abstract
- socket namespace will become unavailable to the processes
- (however, those located in the file system will continue to be
- accessible).</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>ProtectSystem=</varname></term>
-
- <listitem><para>Takes a boolean argument or
- <literal>full</literal>. If true, mounts the
- <filename>/usr</filename> and <filename>/boot</filename>
- directories read-only for processes invoked by this unit. If
- set to <literal>full</literal>, the <filename>/etc</filename>
- directory is mounted read-only, too. This setting ensures that
- any modification of the vendor-supplied operating system (and
- optionally its configuration) is prohibited for the service.
- It is recommended to enable this setting for all long-running
- services, unless they are involved with system updates or need
- to modify the operating system in other ways. Note however
- that processes retaining the CAP_SYS_ADMIN capability can undo
- the effect of this setting. This setting is hence particularly
- useful for daemons which have this capability removed, for
- example with <varname>CapabilityBoundingSet=</varname>.
- Defaults to off.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>ProtectHome=</varname></term>
-
- <listitem><para>Takes a boolean argument or
- <literal>read-only</literal>. If true, the directories
- <filename>/home</filename>, <filename>/root</filename> and
- <filename>/run/user</filename>
- are made inaccessible and empty for processes invoked by this
- unit. If set to <literal>read-only</literal>, the three
- directories are made read-only instead. It is recommended to
- enable this setting for all long-running services (in
- particular network-facing ones), to ensure they cannot get
- access to private user data, unless the services actually
- require access to the user's private data. Note however that
- processes retaining the CAP_SYS_ADMIN capability can undo the
- effect of this setting. This setting is hence particularly
- useful for daemons which have this capability removed, for
- example with <varname>CapabilityBoundingSet=</varname>.
- Defaults to off.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>MountFlags=</varname></term>
-
- <listitem><para>Takes a mount propagation flag:
- <option>shared</option>, <option>slave</option> or
- <option>private</option>, which control whether mounts in the
- file system namespace set up for this unit's processes will
- receive or propagate mounts or unmounts. See
- <citerefentry project='man-pages'><refentrytitle>mount</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details. Defaults to <option>shared</option>. Use
- <option>shared</option> to ensure that mounts and unmounts are
- propagated from the host to the container and vice versa. Use
- <option>slave</option> to run processes so that none of their
- mounts and unmounts will propagate to the host. Use
- <option>private</option> to also ensure that no mounts and
- unmounts from the host will propagate into the unit processes'
- namespace. Note that <option>slave</option> means that file
- systems mounted on the host might stay mounted continuously in
- the unit's namespace, and thus keep the device busy. Note that
- the file system namespace related options
- (<varname>PrivateTmp=</varname>,
- <varname>PrivateDevices=</varname>,
- <varname>ProtectSystem=</varname>,
- <varname>ProtectHome=</varname>,
- <varname>ReadOnlyDirectories=</varname>,
- <varname>InaccessibleDirectories=</varname> and
- <varname>ReadWriteDirectories=</varname>) require that mount
- and unmount propagation from the unit's file system namespace
- is disabled, and hence downgrade <option>shared</option> to
- <option>slave</option>. </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>UtmpIdentifier=</varname></term>
-
- <listitem><para>Takes a four character identifier string for
- an <citerefentry
- project='man-pages'><refentrytitle>utmp</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- and wtmp entry for this service. This should only be
- set for services such as <command>getty</command>
- implementations (such as <citerefentry
- project='die-net'><refentrytitle>agetty</refentrytitle><manvolnum>8</manvolnum></citerefentry>)
- where utmp/wtmp entries must be created and cleared before and
- after execution, or for services that shall be executed as if
- they were run by a <command>getty</command> process (see
- below). If the configured string is longer than four
- characters, it is truncated and the terminal four characters
- are used. This setting interprets %I style string
- replacements. This setting is unset by default, i.e. no
- utmp/wtmp entries are created or cleaned up for this
- service.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>UtmpMode=</varname></term>
-
- <listitem><para>Takes one of <literal>init</literal>,
- <literal>login</literal> or <literal>user</literal>. If
- <varname>UtmpIdentifier=</varname> is set, controls which
- type of <citerefentry
- project='man-pages'><refentrytitle>utmp</refentrytitle><manvolnum>5</manvolnum></citerefentry>/wtmp
- entries for this service are generated. This setting has no
- effect unless <varname>UtmpIdentifier=</varname> is set
- too. If <literal>init</literal> is set, only an
- <constant>INIT_PROCESS</constant> entry is generated and the
- invoked process must implement a
- <command>getty</command>-compatible utmp/wtmp logic. If
- <literal>login</literal> is set, first an
- <constant>INIT_PROCESS</constant> entry, followed by a
- <constant>LOGIN_PROCESS</constant> entry is generated. In
- this case, the invoked process must implement a <citerefentry
- project='die-net'><refentrytitle>login</refentrytitle><manvolnum>1</manvolnum></citerefentry>-compatible
- utmp/wtmp logic. If <literal>user</literal> is set, first an
- <constant>INIT_PROCESS</constant> entry, then a
- <constant>LOGIN_PROCESS</constant> entry and finally a
- <constant>USER_PROCESS</constant> entry is generated. In this
- case, the invoked process may be any process that is suitable
- to be run as session leader. Defaults to
- <literal>init</literal>.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SELinuxContext=</varname></term>
-
- <listitem><para>Set the SELinux security context of the
- executed process. If set, this will override the automated
- domain transition. However, the policy still needs to
- authorize the transition. This directive is ignored if SELinux
- is disabled. If prefixed by <literal>-</literal>, all errors
- will be ignored. See
- <citerefentry project='die-net'><refentrytitle>setexeccon</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for details.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>AppArmorProfile=</varname></term>
-
- <listitem><para>Takes a profile name as argument. The process
- executed by the unit will switch to this profile when started.
- Profiles must already be loaded in the kernel, or the unit
- will fail. This result in a non operation if AppArmor is not
- enabled. If prefixed by <literal>-</literal>, all errors will
- be ignored. </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SmackProcessLabel=</varname></term>
-
- <listitem><para>Takes a <option>SMACK64</option> security
- label as argument. The process executed by the unit will be
- started under this label and SMACK will decide whether the
- process is allowed to run or not, based on it. The process
- will continue to run under the label specified here unless the
- executable has its own <option>SMACK64EXEC</option> label, in
- which case the process will transition to run under that
- label. When not specified, the label that systemd is running
- under is used. This directive is ignored if SMACK is
- disabled.</para>
-
- <para>The value may be prefixed by <literal>-</literal>, in
- which case all errors will be ignored. An empty value may be
- specified to unset previous assignments.</para>
- </listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>IgnoreSIGPIPE=</varname></term>
-
- <listitem><para>Takes a boolean argument. If true, causes
- <constant>SIGPIPE</constant> to be ignored in the executed
- process. Defaults to true because <constant>SIGPIPE</constant>
- generally is useful only in shell pipelines.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>NoNewPrivileges=</varname></term>
-
- <listitem><para>Takes a boolean argument. If true, ensures
- that the service process and all its children can never gain
- new privileges. This option is more powerful than the
- respective secure bits flags (see above), as it also prohibits
- UID changes of any kind. This is the simplest, most effective
- way to ensure that a process and its children can never
- elevate privileges again.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SystemCallFilter=</varname></term>
-
- <listitem><para>Takes a space-separated list of system call
- names. If this setting is used, all system calls executed by
- the unit processes except for the listed ones will result in
- immediate process termination with the
- <constant>SIGSYS</constant> signal (whitelisting). If the
- first character of the list is <literal>~</literal>, the
- effect is inverted: only the listed system calls will result
- in immediate process termination (blacklisting). If running in
- user mode, or in system mode, but without the
- <constant>CAP_SYS_ADMIN</constant> capabiblity (e.g. setting
- <varname>User=nobody</varname>),
- <varname>NoNewPrivileges=yes</varname> is implied. This
- feature makes use of the Secure Computing Mode 2 interfaces of
- the kernel ('seccomp filtering') and is useful for enforcing a
- minimal sandboxing environment. Note that the
- <function>execve</function>,
- <function>rt_sigreturn</function>,
- <function>sigreturn</function>,
- <function>exit_group</function>, <function>exit</function>
- system calls are implicitly whitelisted and do not need to be
- listed explicitly. This option may be specified more than once,
- in which case the filter masks are merged. If the empty string
- is assigned, the filter is reset, all prior assignments will
- have no effect.</para>
-
- <para>If you specify both types of this option (i.e.
- whitelisting and blacklisting), the first encountered will
- take precedence and will dictate the default action
- (termination or approval of a system call). Then the next
- occurrences of this option will add or delete the listed
- system calls from the set of the filtered system calls,
- depending of its type and the default action. (For example, if
- you have started with a whitelisting of
- <function>read</function> and <function>write</function>, and
- right after it add a blacklisting of
- <function>write</function>, then <function>write</function>
- will be removed from the set.) </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SystemCallErrorNumber=</varname></term>
-
- <listitem><para>Takes an <literal>errno</literal> error number
- name to return when the system call filter configured with
- <varname>SystemCallFilter=</varname> is triggered, instead of
- terminating the process immediately. Takes an error name such
- as <constant>EPERM</constant>, <constant>EACCES</constant> or
- <constant>EUCLEAN</constant>. When this setting is not used,
- or when the empty string is assigned, the process will be
- terminated immediately when the filter is
- triggered.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>SystemCallArchitectures=</varname></term>
-
- <listitem><para>Takes a space-separated list of architecture
- identifiers to include in the system call filter. The known
- architecture identifiers are <constant>x86</constant>,
- <constant>x86-64</constant>, <constant>x32</constant>,
- <constant>arm</constant> as well as the special identifier
- <constant>native</constant>. Only system calls of the
- specified architectures will be permitted to processes of this
- unit. This is an effective way to disable compatibility with
- non-native architectures for processes, for example to
- prohibit execution of 32-bit x86 binaries on 64-bit x86-64
- systems. The special <constant>native</constant> identifier
- implicitly maps to the native architecture of the system (or
- more strictly: to the architecture the system manager is
- compiled for). If running in user mode, or in system mode,
- but without the <constant>CAP_SYS_ADMIN</constant>
- capabiblity (e.g. setting <varname>User=nobody</varname>),
- <varname>NoNewPrivileges=yes</varname> is implied. Note
- that setting this option to a non-empty list implies that
- <constant>native</constant> is included too. By default, this
- option is set to the empty list, i.e. no architecture system
- call filtering is applied.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>RestrictAddressFamilies=</varname></term>
-
- <listitem><para>Restricts the set of socket address families
- accessible to the processes of this unit. Takes a
- space-separated list of address family names to whitelist,
- such as
- <constant>AF_UNIX</constant>,
- <constant>AF_INET</constant> or
- <constant>AF_INET6</constant>. When
- prefixed with <constant>~</constant> the listed address
- families will be applied as blacklist, otherwise as whitelist.
- Note that this restricts access to the
- <citerefentry project='man-pages'><refentrytitle>socket</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- system call only. Sockets passed into the process by other
- means (for example, by using socket activation with socket
- units, see
- <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
- are unaffected. Also, sockets created with
- <function>socketpair()</function> (which creates connected
- AF_UNIX sockets only) are unaffected. Note that this option
- has no effect on 32-bit x86 and is ignored (but works
- correctly on x86-64). If running in user mode, or in system
- mode, but without the <constant>CAP_SYS_ADMIN</constant>
- capabiblity (e.g. setting <varname>User=nobody</varname>),
- <varname>NoNewPrivileges=yes</varname> is implied. By
- default, no restriction applies, all address families are
- accessible to processes. If assigned the empty string, any
- previous list changes are undone.</para>
-
- <para>Use this option to limit exposure of processes to remote
- systems, in particular via exotic network protocols. Note that
- in most cases, the local <constant>AF_UNIX</constant> address
- family should be included in the configured whitelist as it is
- frequently used for local communication, including for
- <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- logging.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>Personality=</varname></term>
-
- <listitem><para>Controls which kernel architecture <citerefentry
- project='man-pages'><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry> shall report,
- when invoked by unit processes. Takes one of the architecture identifiers <constant>x86</constant>,
- <constant>x86-64</constant>, <constant>ppc</constant>, <constant>ppc-le</constant>, <constant>ppc64</constant>,
- <constant>ppc64-le</constant>, <constant>s390</constant> or <constant>s390x</constant>. Which personality
- architectures are supported depends on the system architecture. Usually the 64bit versions of the various
- system architectures support their immediate 32bit personality architecture counterpart, but no others. For
- example, <constant>x86-64</constant> systems support the <constant>x86-64</constant> and
- <constant>x86</constant> personalities but no others. The personality feature is useful when running 32-bit
- services on a 64-bit host system. If not specified, the personality is left unmodified and thus reflects the
- personality of the host system's kernel.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>RuntimeDirectory=</varname></term>
- <term><varname>RuntimeDirectoryMode=</varname></term>
-
- <listitem><para>Takes a list of directory names. If set, one
- or more directories by the specified names will be created
- below <filename>/run</filename> (for system services) or below
- <varname>$XDG_RUNTIME_DIR</varname> (for user services) when
- the unit is started, and removed when the unit is stopped. The
- directories will have the access mode specified in
- <varname>RuntimeDirectoryMode=</varname>, and will be owned by
- the user and group specified in <varname>User=</varname> and
- <varname>Group=</varname>. Use this to manage one or more
- runtime directories of the unit and bind their lifetime to the
- daemon runtime. The specified directory names must be
- relative, and may not include a <literal>/</literal>, i.e.
- must refer to simple directories to create or remove. This is
- particularly useful for unprivileged daemons that cannot
- create runtime directories in <filename>/run</filename> due to
- lack of privileges, and to make sure the runtime directory is
- cleaned up automatically after use. For runtime directories
- that require more complex or different configuration or
- lifetime guarantees, please consider using
- <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para></listitem>
- </varlistentry>
-
- </variablelist>
- </refsect1>
-
- <refsect1>
- <title>Environment variables in spawned processes</title>
-
- <para>Processes started by the system are executed in a clean
- environment in which select variables listed below are set. System
- processes started by systemd do not inherit variables from PID 1,
- but processes started by user systemd instances inherit all
- environment variables from the user systemd instance.
- </para>
-
- <variablelist class='environment-variables'>
- <varlistentry>
- <term><varname>$PATH</varname></term>
-
- <listitem><para>Colon-separated list of directories to use
- when launching executables. Systemd uses a fixed value of
- <filename>/usr/local/sbin</filename>:<filename>/usr/local/bin</filename>:<filename>/usr/sbin</filename>:<filename>/usr/bin</filename>:<filename>/sbin</filename>:<filename>/bin</filename>.
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$LANG</varname></term>
-
- <listitem><para>Locale. Can be set in
- <citerefentry project='man-pages'><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- or on the kernel command line (see
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- and
- <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>).
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$USER</varname></term>
- <term><varname>$LOGNAME</varname></term>
- <term><varname>$HOME</varname></term>
- <term><varname>$SHELL</varname></term>
-
- <listitem><para>User name (twice), home directory, and the
- login shell. The variables are set for the units that have
- <varname>User=</varname> set, which includes user
- <command>systemd</command> instances. See
- <citerefentry project='die-net'><refentrytitle>passwd</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$XDG_RUNTIME_DIR</varname></term>
-
- <listitem><para>The directory for volatile state. Set for the
- user <command>systemd</command> instance, and also in user
- sessions. See
- <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$XDG_SESSION_ID</varname></term>
- <term><varname>$XDG_SEAT</varname></term>
- <term><varname>$XDG_VTNR</varname></term>
-
- <listitem><para>The identifier of the session, the seat name,
- and virtual terminal of the session. Set by
- <citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- for login sessions. <varname>$XDG_SEAT</varname> and
- <varname>$XDG_VTNR</varname> will only be set when attached to
- a seat and a tty.</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$MAINPID</varname></term>
-
- <listitem><para>The PID of the units main process if it is
- known. This is only set for control processes as invoked by
- <varname>ExecReload=</varname> and similar. </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$MANAGERPID</varname></term>
-
- <listitem><para>The PID of the user <command>systemd</command>
- instance, set for processes spawned by it. </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$LISTEN_FDS</varname></term>
- <term><varname>$LISTEN_PID</varname></term>
- <term><varname>$LISTEN_FDNAMES</varname></term>
-
- <listitem><para>Information about file descriptors passed to a
- service for socket activation. See
- <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$NOTIFY_SOCKET</varname></term>
-
- <listitem><para>The socket
- <function>sd_notify()</function> talks to. See
- <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$WATCHDOG_PID</varname></term>
- <term><varname>$WATCHDOG_USEC</varname></term>
-
- <listitem><para>Information about watchdog keep-alive notifications. See
- <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- </para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>$TERM</varname></term>
-
- <listitem><para>Terminal type, set only for units connected to
- a terminal (<varname>StandardInput=tty</varname>,
- <varname>StandardOutput=tty</varname>, or
- <varname>StandardError=tty</varname>). See
- <citerefentry project='man-pages'><refentrytitle>termcap</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
- </para></listitem>
- </varlistentry>
- </variablelist>
-
- <para>Additional variables may be configured by the following
- means: for processes spawned in specific units, use the
- <varname>Environment=</varname>, <varname>EnvironmentFile=</varname>
- and <varname>PassEnvironment=</varname> options above; to specify
- variables globally, use <varname>DefaultEnvironment=</varname>
- (see
- <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>)
- or the kernel option <varname>systemd.setenv=</varname> (see
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>).
- Additional variables may also be set through PAM,
- cf. <citerefentry project='man-pages'><refentrytitle>pam_env</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
- </refsect1>
-
- <refsect1>
- <title>See Also</title>
- <para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>tmpfiles.d</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
- <citerefentry project='man-pages'><refentrytitle>exec</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- </para>
- </refsect1>
-
-</refentry>