Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ 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
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refnamediv>
<refname>systemd.exec</refname>
- <refpurpose>systemd execution environment configuration</refpurpose>
+ <refpurpose>Execution environment configuration</refpurpose>
</refnamediv>
<refsynopsisdiv>
<para><filename>systemd.service</filename>,
<filename>systemd.socket</filename>,
- <filename>systemd.mount</filename></para>
+ <filename>systemd.mount</filename>,
+ <filename>systemd.swap</filename></para>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
- <para>Unit configuration files for services, sockets
- and mount points share a subset of configuration
- options which define the execution environment of
- spawned processes.</para>
+ <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 three unit types. See
+ 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.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] resp. [Mount] section, depending on the unit
+ [Socket], [Mount] resp. [Swap] section, depending on the unit
type.</para>
</refsect1>
<listitem><para>Takes an absolute
directory path. Sets the working
- directory for executed
- processes.</para></listitem>
+ 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>
<listitem><para>Sets the supplementary
Unix groups the processes are executed
- as. This takes a space seperated list
+ 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. This option does
- not override but extend the list of
+ not override but extends the list of
supplementary groups configured in the
system group database for the
user.</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>OOMAdjust=</varname></term>
+ <term><varname>OOMScoreAdjust=</varname></term>
<listitem><para>Sets the adjustment
level for the Out-Of-Memory killer for
executed processes. Takes an integer
- between -17 (to disable OOM killing
- for this process) and 15 (to make
+ 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>
<listitem><para>Controls the CPU
affinity of the executed
- processes. Takes a space-seperated
+ processes. Takes a space-separated
list of CPU indexes. See
<citerefentry><refentrytitle>sched_setaffinity</refentrytitle><manvolnum>2</manvolnum></citerefentry>
for details.</para></listitem>
octal notation. See
<citerefentry><refentrytitle>umask</refentrytitle><manvolnum>2</manvolnum></citerefentry>
for details. Defaults to
- 0002.</para></listitem>
+ 0022.</para></listitem>
</varlistentry>
<varlistentry>
<listitem><para>Sets environment
variables for executed
- processes. Takes a space-seperated
+ processes. Takes a space-separated
list of variable assignments. This
option may be specified more than once
in which case all listed variables
<varname>Environment=</varname> but
reads the environment variables from a
text file. The text file should
- contain new-line seperated variable
+ contain new-line separated variable
assignments. Empty lines and lines
starting with ; or # will be ignored,
- which may be used for
- commenting.</para></listitem>
+ which may be used for commenting. The
+ parser strips leading and
+ trailing whitespace from the values
+ of assignments, unless you use
+ double quotes (").
+ The
+ argument passed should be an absolute
+ file name, 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. 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>
below) and the executed process
becomes the controlling process of the
terminal. If the terminal is already
- being controlled by another process it
- is waited until that process releases
- the
- terminal. <option>tty-force</option>
+ 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
<option>null</option>,
<option>tty</option>,
<option>syslog</option>,
- <option>kmsg</option> or
+ <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
terminal. <option>syslog</option>
connects standard output to the
<citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- system logger. <option>kmsg</option>
+ 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>socket</option>
- connects standard output to a socket
- from socket activation, semantics are
+ <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
- <option>inherit</option>.</para></listitem>
+ This setting defaults to the value set
+ with
+ <option>DefaultStandardOutput=</option>
+ in
+ <citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ which defaults to
+ <option>journal</option>.</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>StandardOutput=</varname></term>
+ <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>StandardError=</varname>,
- whith one exception: if set to
+ <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
+ setting defaults to the value set with
+ <option>DefaultStandardError=</option>
+ in
+ <citerefentry><refentrytitle>systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ which defaults to
<option>inherit</option>.</para></listitem>
</varlistentry>
<varlistentry>
<filename>/dev/console</filename>.</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>SyslogIdentifer=</varname></term>
+ <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
the default log level specified
here. The interpretation of these
prefixes may be disabled with
- <varname>SyslogNoPrefix=</varname>,
+ <varname>SyslogLevelPrefix=</varname>,
see below. For details see
- <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
Defaults to
<option>info</option>.</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>SyslogNoPrefix=</varname></term>
+ <term><varname>SyslogLevelPrefix=</varname></term>
<listitem><para>Takes a boolean
- argument. If false and
+ argument. If true and
<varname>StandardOutput=</varname> or
<varname>StandardError=</varname> are
set to <option>syslog</option> or
are prefixed with a log level will be
passed on to syslog with this log
level set but the prefix removed. If
- set to true, the interpretation of
+ 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>7</manvolnum></citerefentry>.
- Defaults to false.</para></listitem>
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ Defaults to true.</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>TimerSlackNS=</varname></term>
+ <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
+ 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.</para></listitem>
+ 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>
various resource limits for executed
processes. See
<citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
- for details.</para></listitem>
+ for details. Use the string
+ <varname>infinity</varname> to
+ configure no limit on a specific
+ resource.</para></listitem>
</varlistentry>
<varlistentry>
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
+ 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.</para></listitem>
+ 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>Capabilities=</varname></term>
- <listitem><para>Controls the
+ <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>
- set for the executed process. Take a
- capability string as described in
- <citerefentry><refentrytitle>cap_from_text</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- Note that this capability set is
- usually influenced by the capabilities
- attached to the executed
- file.</para></listitem>
+ for details. Takes a whitespace
+ separated list of capability names as
+ read by
+ <citerefentry><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ Capabilities listed will be included
+ in the bounding set, all others are
+ removed. If the list of capabilities
+ is prefixed with ~ all but the listed
+ capabilities will be included, the
+ effect of the assignment
+ inverted. Note that this option also
+ effects 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.</para></listitem>
</varlistentry>
<varlistentry>
<option>keep-caps-locked</option>,
<option>no-setuid-fixup</option>,
<option>no-setuid-fixup-locked</option>,
- <option>no-setuid-noroot</option> and/or
- <option>no-setuid-noroot-locked</option>.
+ <option>noroot</option> and/or
+ <option>noroot-locked</option>.
</para></listitem>
</varlistentry>
<varlistentry>
- <term><varname>CapabilityBoundingSetDrop=</varname></term>
-
+ <term><varname>Capabilities=</varname></term>
<listitem><para>Controls the
- capability bounding set drop set for
- the executed process. See
<citerefentry><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
- for details. Takes a list of
- capability names as read by
- <citerefentry><refentrytitle>cap_from_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- </para></listitem>
+ 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>
<listitem><para>Controls the control
groups the executed processes shall be
- made member of. Takes a
- space-seperated list of cgroup
+ made members of. Takes a
+ space-separated list of cgroup
identifiers. A cgroup identifier has a
format like
<filename>cpu:/foo/bar</filename>,
where "cpu" identifies 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
+ 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. This
option may be used to place executed
processes in arbitrary groups in
- arbitrary hierachies -- which can be
- configured externally with additional execution limits. By default
- systemd will place all executed
- processes in seperate per-unit control
- groups (named after the unit) in the
- systemd named hierarchy. Since every
- process can be in one group per
- hierarchy only overriding the control group
- path in the named systemd hierarchy
- will disable automatic placement in
- the default group. For details about control
- groups see <ulink
+ arbitrary hierarchies -- which can be
+ configured externally 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. Since every process
+ can be in one group per hierarchy only
+ overriding the control group path in
+ the named systemd hierarchy will
+ disable automatic placement in the
+ default group. This option is
+ primarily intended to place executed
+ processes in specific paths in
+ specific kernel controller
+ hierarchies. It is however 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></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 case 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.</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,
+ resp. Terabytes (to the base
+ 1024). 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 resp.
+ creating of the specific device node
+ by the unit. 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, resp. Terabytes (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>
to limit access a process might have
to the main file-system
hierarchy. Each setting takes a
- space-seperated list of absolute
+ space-separated list of absolute
directory paths. Directories listed in
<varname>ReadWriteDirectories=</varname>
are accessible from within the
usual file access controls would
permit this. Directories listed in
<varname>InaccessibleDirectories=</varname>
- will be made inaccesible for processes
+ 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
- seperately in these setttings to
+ separately in these settings to
ensure the same limited access. These
options may be specified more than
once in which case all directories
<term><varname>PrivateTmp=</varname></term>
<listitem><para>Takes a boolean
- argument. If true sets up a new
- namespace for the executed processes
- and mounts a private
+ argument. If true sets up a new file
+ system namespace for the executed
+ processes and mounts a private
<filename>/tmp</filename> directory
inside it, that is not shared by
processes outside of the
process, but makes sharing between
processes via
<filename>/tmp</filename>
- impossible. Defaults to false.</para></listitem>
+ impossible. 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>
<option>shared</option>,
<option>slave</option> or
<option>private</option>, which
- control whether namespaces set up with
- <varname>ReadWriteDirectories=</varname>,
- <varname>ReadOnlyDirectories=</varname>
- and
- <varname>InaccessibleDirectories=</varname>
- receive or propagate new mounts
- from/to the main namespace. See
+ 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>1</manvolnum></citerefentry>
- for details. Defaults to
- <option>shared</option>, i.e. the new
- namespace will both receive new mount
- points from the main namespace as well
- as propagate new mounts to
- it.</para></listitem>
+ 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.</para></listitem>
</varlistentry>
</variablelist>
<refsect1>
<title>See Also</title>
<para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
+ <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.mount</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>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff