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| Copyright 2010 Lennart Poettering |
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| |
| <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>Options</title> |
| |
| <variablelist class='unit-directives'> |
| |
| <varlistentry> |
| <term><varname>WorkingDirectory=</varname></term> |
| |
| <listitem><para>Takes an absolute |
| directory path. Sets the working |
| directory for executed processes. 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.</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><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
| system call. If this is used it must |
| be ensured that the process and all |
| its auxiliary files are available in |
| the <function>chroot()</function> |
| jail.</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="http://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 IO 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 IO scheduling |
| priority for executed processes. Takes |
| an integer between 0 (highest |
| priority) and 7 (lowest priority). The |
| available priorities depend on the |
| selected IO 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 space-separated |
| list of CPU indexes. This option may |
| be specified more than once in which |
| case the specificed 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, and $ 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>. |
| </para> |
| |
| <para> |
| See |
| <citerefentry><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 and 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 file name or wildcard |
| expression, optionally prefixed with |
| "-", which indicates that if the file |
| does not exist it won't 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. 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>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>. 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. 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. |
| <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. <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. 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><refentrytitle>inetd</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| daemon. 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>syslog</option>, |
| <option>kmsg</option>, |
| <option>journal</option>, |
| <option>syslog+console</option>, |
| <option>kmsg+console</option>, |
| <option>journal+console</option> or |
| <option>socket</option>. If set to |
| <option>inherit</option> the file |
| descriptor of standard input is |
| duplicated for standard output. If set |
| to <option>null</option> standard |
| output will be connected to |
| <filename>/dev/null</filename>, |
| i.e. everything written to it will be |
| lost. If set to <option>tty</option> |
| standard output will be connected 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. <option>syslog</option> |
| connects standard output to the |
| <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> |
| system syslog |
| service. <option>kmsg</option> |
| connects it with the kernel log buffer |
| which is accessible via |
| <citerefentry><refentrytitle>dmesg</refentrytitle><manvolnum>1</manvolnum></citerefentry>. <option>journal</option> |
| connects it 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 is implicitly stored |
| in the journal as well, those options |
| are hence supersets of this |
| one). <option>syslog+console</option>, |
| <option>journal+console</option> and |
| <option>kmsg+console</option> work |
| similarly but copy the output to the |
| system console as |
| well. <option>socket</option> connects |
| standard output to a socket from |
| socket activation, semantics are |
| similar to the respective option of |
| <varname>StandardInput=</varname>. |
| 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>.</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>.</para></listitem> |
| </varlistentry> |
| <varlistentry> |
| <term><varname>TTYPath=</varname></term> |
| <listitem><para>Sets the terminal |
| device node to use if standard input, |
| output or stderr 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 syslog 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> or |
| <option>kmsg</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><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>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><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>These settings control |
| various resource limits for executed |
| processes. See |
| <citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
| for details. Use the string |
| <varname>infinity</varname> to |
| configure no limit on a specific |
| resource.</para></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><refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| for details.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>TCPWrapName=</varname></term> |
| <listitem><para>If this is a |
| socket-activated service this sets the |
| tcpwrap service name to check the |
| permission for the current connection |
| with. This is only useful in |
| conjunction with socket-activated |
| services, and stream sockets (TCP) in |
| particular. It has no effect on other |
| socket types (e.g. datagram/UDP) and |
| on processes unrelated to socket-based |
| activation. If the tcpwrap |
| verification fails daemon start-up |
| will fail and the connection is |
| terminated. See |
| <citerefentry><refentrytitle>tcpd</refentrytitle><manvolnum>8</manvolnum></citerefentry> |
| for details. Note that this option may |
| be used to do access control checks |
| only. Shell commands and commands |
| described in |
| <citerefentry><refentrytitle>hosts_options</refentrytitle><manvolnum>5</manvolnum></citerefentry> |
| are not supported.</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><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| for details. Takes a whitespace |
| separated list of capability names as |
| read by |
| <citerefentry><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>, |
| e.g. <literal>CAP_SYS_ADMIN |
| CAP_DAC_OVERRIDE |
| CAP_SYS_PTRACE</literal>. |
| 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, on top of what |
| <varname>Capabilities=</varname> |
| does. 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>SecureBits=</varname></term> |
| <listitem><para>Controls the secure |
| bits set for the executed process. See |
| <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| for details. Takes a list of strings: |
| <option>keep-caps</option>, |
| <option>keep-caps-locked</option>, |
| <option>no-setuid-fixup</option>, |
| <option>no-setuid-fixup-locked</option>, |
| <option>noroot</option> and/or |
| <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.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>Capabilities=</varname></term> |
| <listitem><para>Controls the |
| <citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| set for the executed process. Take a |
| capability string describing the |
| effective, permitted and inherited |
| capability sets as documented in |
| <citerefentry><refentrytitle>cap_from_text</refentrytitle><manvolnum>3</manvolnum></citerefentry>. |
| Note that these capability sets are |
| usually influenced by the capabilities |
| attached to the executed file. Due to |
| that |
| <varname>CapabilityBoundingSet=</varname> |
| is probably the much more useful |
| setting.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>ControlGroup=</varname></term> |
| |
| <listitem><para>Controls the control |
| groups the executed processes shall be |
| made members of. Takes a |
| space-separated list of cgroup |
| identifiers. A cgroup identifier is |
| formatted like |
| <filename>cpu:/foo/bar</filename>, |
| where "cpu" indicates the kernel |
| control group controller used, and |
| <filename>/foo/bar</filename> is the |
| control group path. The controller |
| name and ":" may be omitted in which |
| case the named systemd control group |
| hierarchy is implied. Alternatively, |
| the path and ":" may be omitted, in |
| which case the default control group |
| path for this unit is implied.</para> |
| |
| <para>This option may be used to place |
| executed processes in arbitrary groups |
| in arbitrary hierarchies -- which may |
| then be externally configured with |
| additional execution limits. By |
| default systemd will place all |
| executed processes in separate |
| per-unit control groups (named after |
| the unit) in the systemd named |
| hierarchy. This option is primarily |
| intended to place executed processes |
| in specific paths in specific kernel |
| controller hierarchies. It is not |
| recommended to manipulate the service |
| control group path in the systemd |
| named hierarchy. For details about |
| control groups see <ulink |
| url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.</para> |
| |
| <para>This option may appear more than |
| once, in which case the list of |
| control group assignments is |
| merged. If the same hierarchy gets two |
| different paths assigned only the |
| later setting will take effect. If the |
| empty string is assigned to this |
| option the list of control group |
| assignments is reset, all previous |
| assignments will have no |
| effect.</para> |
| |
| <para>Note that the list of control |
| group assignments of a unit is |
| extended implicitly based on the |
| settings of |
| <varname>DefaultControllers=</varname> |
| of |
| <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, |
| but a unit's |
| <varname>ControlGroup=</varname> |
| setting for a specific controller |
| takes precedence.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>ControlGroupModify=</varname></term> |
| <listitem><para>Takes a boolean |
| argument. If true, the control groups |
| created for this unit will be owned by |
| the user specified with |
| <varname>User=</varname> (and the |
| appropriate group), and he/she can create |
| subgroups as well as add processes to |
| the group.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>ControlGroupPersistent=</varname></term> |
| <listitem><para>Takes a boolean |
| argument. If true, the control groups |
| created for this unit will be marked |
| to be persistent, i.e. systemd will |
| not remove them when stopping the |
| unit. The default is false, meaning |
| that the control groups will be |
| removed when the unit is stopped. For |
| details about the semantics of this |
| logic see <ulink |
| url="http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups">PaxControlGroups</ulink>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>ControlGroupAttribute=</varname></term> |
| |
| <listitem><para>Set a specific control |
| group attribute for executed |
| processes, and (if needed) add the |
| executed processes to a cgroup in the |
| hierarchy of the controller the |
| attribute belongs to. Takes two |
| space-separated arguments: the |
| attribute name (syntax is |
| <literal>cpu.shares</literal> where |
| <literal>cpu</literal> refers to a |
| specific controller and |
| <literal>shares</literal> to the |
| attribute name), and the attribute |
| value. Example: |
| <literal>ControlGroupAttribute=cpu.shares |
| 512</literal>. If this option is used |
| for an attribute that belongs to a |
| kernel controller hierarchy the unit |
| is not already configured to be added |
| to (for example via the |
| <literal>ControlGroup=</literal> |
| option) then the unit will be added to |
| the controller and the default unit |
| cgroup path is implied. Thus, using |
| <varname>ControlGroupAttribute=</varname> |
| is in most cases sufficient to make |
| use of control group enforcements, |
| explicit |
| <varname>ControlGroup=</varname> are |
| only necessary in case the implied |
| default control group path for a |
| service is not desirable. For details |
| about control group attributes see |
| <ulink |
| url="http://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>. This |
| option may appear more than once, in |
| order to set multiple control group |
| attributes. If this option is used |
| multiple times for the same cgroup |
| attribute only the later setting takes |
| effect. If the empty string is |
| assigned to this option the list of |
| attributes is reset, all previous |
| cgroup attribute settings have no |
| effect, including those done with |
| <varname>CPUShares=</varname>, |
| <varname>MemoryLimit=</varname>, |
| <varname>MemorySoftLimit</varname>, |
| <varname>DeviceAllow=</varname>, |
| <varname>DeviceDeny=</varname>, |
| <varname>BlockIOWeight=</varname>, |
| <varname>BlockIOReadBandwidth=</varname>, |
| <varname>BlockIOWriteBandwidth=</varname>. |
| </para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>CPUShares=</varname></term> |
| |
| <listitem><para>Assign the specified |
| overall CPU time shares to the |
| processes executed. Takes an integer |
| value. This controls the |
| <literal>cpu.shares</literal> control |
| group attribute, which defaults to |
| 1024. For details about this control |
| group attribute see <ulink |
| url="http://www.kernel.org/doc/Documentation/scheduler/sched-design-CFS.txt">sched-design-CFS.txt</ulink>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>MemoryLimit=</varname></term> |
| <term><varname>MemorySoftLimit=</varname></term> |
| |
| <listitem><para>Limit the overall memory usage |
| of the executed processes to a certain |
| size. Takes a memory size in bytes. If |
| the value is suffixed with K, M, G or |
| T the specified memory size is parsed |
| as Kilobytes, Megabytes, Gigabytes, |
| or Terabytes (to the base |
| 1024), respectively. This controls the |
| <literal>memory.limit_in_bytes</literal> |
| and |
| <literal>memory.soft_limit_in_bytes</literal> |
| control group attributes. For details |
| about these control group attributes |
| see <ulink |
| url="http://www.kernel.org/doc/Documentation/cgroups/memory.txt">memory.txt</ulink>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>DeviceAllow=</varname></term> |
| <term><varname>DeviceDeny=</varname></term> |
| |
| <listitem><para>Control access to |
| specific device nodes by the executed processes. Takes two |
| space separated strings: a device node |
| path (such as |
| <filename>/dev/null</filename>) |
| followed by a combination of r, w, m |
| to control reading, writing, or |
| creating of the specific device node |
| by the unit, respectively. This controls the |
| <literal>devices.allow</literal> |
| and |
| <literal>devices.deny</literal> |
| control group attributes. For details |
| about these control group attributes |
| see <ulink |
| url="http://www.kernel.org/doc/Documentation/cgroups/devices.txt">devices.txt</ulink>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>BlockIOWeight=</varname></term> |
| |
| <listitem><para>Set the default or |
| per-device overall block IO weight |
| value for the executed |
| processes. Takes either a single |
| weight value (between 10 and 1000) to |
| set the default block IO weight, or a |
| space separated pair of a file path |
| and a weight value to specify the |
| device specific weight value (Example: |
| "/dev/sda 500"). The file path may be |
| specified as path to a block device |
| node or as any other file in which |
| case the backing block device of the |
| file system of the file is |
| determined. This controls the |
| <literal>blkio.weight</literal> and |
| <literal>blkio.weight_device</literal> |
| control group attributes, which |
| default to 1000. Use this option |
| multiple times to set weights for |
| multiple devices. For details about |
| these control group attributes see |
| <ulink |
| url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>BlockIOReadBandwidth=</varname></term> |
| <term><varname>BlockIOWriteBandwidth=</varname></term> |
| |
| <listitem><para>Set the per-device |
| overall block IO bandwidth limit for |
| the executed processes. Takes a space |
| separated pair of a file path and a |
| bandwidth value (in bytes per second) |
| to specify the device specific |
| bandwidth. The file path may be |
| specified as path to a block device |
| node or as any other file in which |
| case the backing block device of the |
| file system of the file is determined. |
| If the bandwidth is suffixed with K, M, |
| G, or T the specified bandwidth is |
| parsed as Kilobytes, Megabytes, |
| Gigabytes, or Terabytes, respectively (Example: |
| "/dev/disk/by-path/pci-0000:00:1f.2-scsi-0:0:0:0 |
| 5M"). This controls the |
| <literal>blkio.read_bps_device</literal> |
| and |
| <literal>blkio.write_bps_device</literal> |
| control group attributes. Use this |
| option multiple times to set bandwidth |
| limits for multiple devices. For |
| details about these control group |
| attributes see <ulink |
| url="http://www.kernel.org/doc/Documentation/cgroups/blkio-controller.txt">blkio-controller.txt</ulink>.</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 name space 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. Note |
| that restricting access with these |
| options does not extend to submounts |
| of a directory. You must list |
| submounts separately in these settings |
| to ensure the same limited |
| access. 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></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 are 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. All temporary data created |
| by service will be removed after service |
| is stopped. Defaults to |
| false.</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.</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 the file system |
| namespace set up for this unit's |
| processes will receive or propagate |
| new mounts. See |
| <citerefentry><refentrytitle>mount</refentrytitle><manvolnum>2</manvolnum></citerefentry> |
| for details. Default to |
| <option>shared</option>.</para></listitem> |
| </varlistentry> |
| |
| <varlistentry> |
| <term><varname>UtmpIdentifier=</varname></term> |
| |
| <listitem><para>Takes a four |
| character identifier string for an |
| utmp/wtmp entry for this service. This |
| should only be set for services such |
| as <command>getty</command> |
| implementations where utmp/wtmp |
| entries must be created and cleared |
| before and after execution. 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>IgnoreSIGPIPE=</varname></term> |
| |
| <listitem><para>Takes a boolean |
| argument. If true causes SIGPIPE to be |
| ignored in the executed |
| process. Defaults to true, since |
| SIGPIPE 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 |
| process except for the listed ones |
| will result in immediate process |
| termination with the SIGSYS 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 this option is used |
| <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 don't |
| 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></listitem> |
| </varlistentry> |
| |
| </variablelist> |
| </refsect1> |
| |
| <refsect1> |
| <title>See Also</title> |
| <para> |
| <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, |
| <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</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.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry> |
| </para> |
| </refsect1> |
| |
| </refentry> |