1328 lines
63 KiB
XML
1328 lines
63 KiB
XML
<?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>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.</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.</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>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>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 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>These settings set both soft and hard limits
|
||
of various resources 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>
|
||
|
||
<table>
|
||
<title>Limit directives and their equivalent with ulimit</title>
|
||
|
||
<tgroup cols='2'>
|
||
<colspec colname='directive' />
|
||
<colspec colname='equivalent' />
|
||
<thead>
|
||
<row>
|
||
<entry>Directive</entry>
|
||
<entry>ulimit equivalent</entry>
|
||
</row>
|
||
</thead>
|
||
<tbody>
|
||
<row>
|
||
<entry>LimitCPU</entry>
|
||
<entry>ulimit -t</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitFSIZE</entry>
|
||
<entry>ulimit -f</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitDATA</entry>
|
||
<entry>ulimit -d</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitSTACK</entry>
|
||
<entry>ulimit -s</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitCORE</entry>
|
||
<entry>ulimit -c</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitRSS</entry>
|
||
<entry>ulimit -m</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitNOFILE</entry>
|
||
<entry>ulimit -n</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitAS</entry>
|
||
<entry>ulimit -v</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitNPROC</entry>
|
||
<entry>ulimit -u</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitMEMLOCK</entry>
|
||
<entry>ulimit -l</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitLOCKS</entry>
|
||
<entry>ulimit -x</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitSIGPENDING</entry>
|
||
<entry>ulimit -i</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitMSGQUEUE</entry>
|
||
<entry>ulimit -q</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitNICE</entry>
|
||
<entry>ulimit -e</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitRTPRIO</entry>
|
||
<entry>ulimit -r</entry>
|
||
</row>
|
||
<row>
|
||
<entry>LimitRTTIME</entry>
|
||
<entry>No equivalent</entry>
|
||
</row>
|
||
</tbody>
|
||
</tgroup>
|
||
</table>
|
||
</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, 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. 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>Capabilities=</varname></term>
|
||
<listitem><para>Controls the
|
||
<citerefentry project='man-pages'><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 project='mankier'><refentrytitle>cap_from_text</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
|
||
Note that these capability sets are usually influenced (and
|
||
filtered) by the capabilities attached to the executed file.
|
||
Due to that <varname>CapabilityBoundingSet=</varname> is
|
||
probably a much more useful setting.</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. 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.</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 and 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 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 and this option is
|
||
used, <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 and this option
|
||
is used, <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
|
||
<constant>x86</constant> and <constant>x86-64</constant>. This
|
||
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>$LISTEN_PID</varname></term>
|
||
|
||
<listitem><para>Information about file descriptors passed to a
|
||
service for socket activation. See
|
||
<citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
|
||
</para></listitem>
|
||
</varlistentry>
|
||
|
||
<varlistentry>
|
||
<term><varname>$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> and
|
||
<varname>EnvironmentFile=</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.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>
|