between -20 (highest priority) and 19
<
citerefentry><
refentrytitle>setpriority</
refentrytitle><
manvolnum>2</
manvolnum></
citerefentry>
for details.</
para></
listitem>
<
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 for details.</
para></
listitem>
<
term><
varname>IOSchedulingClass=</
varname></
term>
<
listitem><
para>Sets the IO scheduling
class for executed processes. Takes an
integer between 0 and 3 or one of the
strings <
option>none</
option>,
<
option>realtime</
option>,
<
option>best-effort</
option> or
<
option>idle</
option>. See
<
citerefentry><
refentrytitle>ioprio_set</
refentrytitle><
manvolnum>2</
manvolnum></
citerefentry>
for details.</
para></
listitem>
<
term><
varname>IOSchedulingPriority=</
varname></
term>
<
listitem><
para>Sets the IO scheduling
priority for executed processes. Takes
an integer between 0 (highest
priority) and 7 (lowest priority). The
available priorities depend on the
selected IO scheduling class (see
<
citerefentry><
refentrytitle>ioprio_set</
refentrytitle><
manvolnum>2</
manvolnum></
citerefentry>
for details.</
para></
listitem>
<
term><
varname>CPUSchedulingPolicy=</
varname></
term>
<
listitem><
para>Sets the CPU
scheduling policy for executed
<
citerefentry><
refentrytitle>sched_setscheduler</
refentrytitle><
manvolnum>2</
manvolnum></
citerefentry>
for details.</
para></
listitem>
<
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>
<
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>
<
term><
varname>CPUAffinity=</
varname></
term>
<
listitem><
para>Controls the CPU
processes. Takes a space-separated
list of CPU indexes. This option may
be specified more than once in which
case the specificed CPU affinity masks
are merged. If the empty string is
assigned the mask is reset, all
assignments prior to this will have no
<
citerefentry><
refentrytitle>sched_setaffinity</
refentrytitle><
manvolnum>2</
manvolnum></
citerefentry>
for details.</
para></
listitem>
<
term><
varname>UMask=</
varname></
term>
<
listitem><
para>Controls the file mode
creation mask. Takes an access mode in
<
citerefentry><
refentrytitle>umask</
refentrytitle><
manvolnum>2</
manvolnum></
citerefentry>
<
term><
varname>Environment=</
varname></
term>
<
listitem><
para>Sets environment
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. $ character has
If you need to assign a value containing spaces
to a variable, use double quotes (")
for the assignment.</
para>
<
programlisting>Environment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"</
programlisting>
gives three variables <
literal>VAR1</
literal>,
<
literal>VAR2</
literal>, <
literal>VAR3</
literal>.
<
citerefentry><
refentrytitle>environ</
refentrytitle><
manvolnum>7</
manvolnum></
citerefentry>
for details about environment variables.</
para></
listitem>
<
term><
varname>EnvironmentFile=</
varname></
term>
<
listitem><
para>Similar to
<
varname>Environment=</
varname> but
reads the environment variables from a
text file. The text file should
contain new-line separated variable
assignments. Empty lines and lines
starting with ; or # will be ignored,
which may be used for commenting. A line
ending with a backslash will be concatenated
with the following one, allowing multiline variable
definitions. The parser strips leading
and trailing whitespace from the values
of assignments, unless you use
double quotes (").</
para>
<
para>The argument passed should be an
absolute file name or wildcard
expression, optionally prefixed with
"-", which indicates that if the file
does not exist it won't be read and no
error or warning message is logged.
This option may be specified more than
once in which case all specified files
are read. If the empty string is
assigned to this option the list of
file to read is reset, all prior
assignments have no effect.</
para>
<
para>The files listed with this
directive will be read shortly before
the process is executed. Settings from
these files override settings made
<
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>
<
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-force</
option>,
<
option>tty-fail</
option> or
<
option>socket</
option>. If
<
option>null</
option> is selected
standard input will be connected to
i.e. all read attempts by the process
will result in immediate EOF. If
<
option>tty</
option> is selected
standard input is connected to a TTY
<
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
<
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
terminal. <
option>tty-fail</
option> is
similar to <
option>tty</
option> but if
the terminal already has a controlling
process start-up of the executed
<
option>socket</
option> option is only
valid in socket-activated services,
and only when the socket configuration
<
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
<
citerefentry><
refentrytitle>inetd</
refentrytitle><
manvolnum>8</
manvolnum></
citerefentry>
daemon. This setting defaults to
<
option>null</
option>.</
para></
listitem>
<
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>journal</
option>,
<
option>syslog+console</
option>,
<
option>kmsg+console</
option>,
<
option>journal+console</
option> or
<
option>socket</
option>. If set to
<
option>inherit</
option> the file
descriptor of standard input is
duplicated for standard output. If set
to <
option>null</
option> standard
output will be connected to
i.e. everything written to it will be
lost. If set to <
option>tty</
option>
standard output will be connected to a
<
varname>TTYPath=</
varname>, see
below). If the TTY is used for output
only the executed process will not
become the controlling process of the
terminal, and will not fail or wait
for other processes to release the
terminal. <
option>syslog</
option>
connects standard output to the
<
citerefentry><
refentrytitle>syslog</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>
service. <
option>kmsg</
option>
connects it with the kernel log buffer
<
citerefentry><
refentrytitle>dmesg</
refentrytitle><
manvolnum>1</
manvolnum></
citerefentry>. <
option>journal</
option>
connects it with the journal which is
<
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
well. <
option>socket</
option> connects
standard output to a socket from
socket activation, semantics are
similar to the respective option of
<
varname>StandardInput=</
varname>.
This setting defaults to the value set
<
option>DefaultStandardOutput=</
option>
<
citerefentry><
refentrytitle>
systemd-system.conf</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
option>journal</
option>.</
para></
listitem>
<
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
<
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>
<
citerefentry><
refentrytitle>
systemd-system.conf</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
option>inherit</
option>.</
para></
listitem>
<
term><
varname>TTYPath=</
varname></
term>
<
listitem><
para>Sets the terminal
device node to use if standard input,
output or stderr are connected to a
TTY (see above). Defaults to
<
filename>/
dev/
console</
filename>.</
para></
listitem>
<
term><
varname>TTYReset=</
varname></
term>
<
listitem><
para>Reset the terminal
<
varname>TTYPath=</
varname> before and
after execution. Defaults to
<
literal>no</
literal>.</
para></
listitem>
<
term><
varname>TTYVHangup=</
varname></
term>
<
listitem><
para>Disconnect all clients
which have opened the terminal device
<
varname>TTYPath=</
varname>
before and after execution. Defaults
<
literal>no</
literal>.</
para></
listitem>
<
term><
varname>TTYVTDisallocate=</
varname></
term>
<
listitem><
para>If the terminal
<
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
<
literal>no</
literal>.</
para></
listitem>
<
term><
varname>SyslogIdentifier=</
varname></
term>
<
listitem><
para>Sets the process name
to prefix log lines sent to syslog or
the kernel log buffer with. If not set
defaults to the process name of the
executed process. This option is only
<
varname>StandardOutput=</
varname> or
<
varname>StandardError=</
varname> are
set to <
option>syslog</
option> or
<
option>kmsg</
option>.</
para></
listitem>
<
term><
varname>SyslogFacility=</
varname></
term>
<
listitem><
para>Sets the syslog
facility to use when logging to
syslog. One of <
option>kern</
option>,
<
option>authpriv</
option>,
<
option>local6</
option> or
<
option>local7</
option>. See
<
citerefentry><
refentrytitle>syslog</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>
for details. This option is only
<
varname>StandardOutput=</
varname> or
<
varname>StandardError=</
varname> are
set to <
option>syslog</
option>.
<
option>daemon</
option>.</
para></
listitem>
<
term><
varname>SyslogLevel=</
varname></
term>
<
listitem><
para>Default syslog level
to use when logging to syslog or the
kernel log buffer. One of
<
option>warning</
option>,
<
option>debug</
option>. See
<
citerefentry><
refentrytitle>syslog</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>
for details. This option is only
<
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>.
<
option>info</
option>.</
para></
listitem>
<
term><
varname>SyslogLevelPrefix=</
varname></
term>
<
listitem><
para>Takes a boolean
<
varname>StandardOutput=</
varname> or
<
varname>StandardError=</
varname> are
set to <
option>syslog</
option>,
<
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>
<
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
<
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
<
term><
varname>LimitCPU=</
varname></
term>
<
term><
varname>LimitFSIZE=</
varname></
term>
<
term><
varname>LimitDATA=</
varname></
term>
<
term><
varname>LimitSTACK=</
varname></
term>
<
term><
varname>LimitCORE=</
varname></
term>
<
term><
varname>LimitRSS=</
varname></
term>
<
term><
varname>LimitNOFILE=</
varname></
term>
<
term><
varname>LimitAS=</
varname></
term>
<
term><
varname>LimitNPROC=</
varname></
term>
<
term><
varname>LimitMEMLOCK=</
varname></
term>
<
term><
varname>LimitLOCKS=</
varname></
term>
<
term><
varname>LimitSIGPENDING=</
varname></
term>
<
term><
varname>LimitMSGQUEUE=</
varname></
term>
<
term><
varname>LimitNICE=</
varname></
term>
<
term><
varname>LimitRTPRIO=</
varname></
term>
<
term><
varname>LimitRTTIME=</
varname></
term>
<
listitem><
para>These settings control
various resource limits for executed
<
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>
<
term><
varname>PAMName=</
varname></
term>
<
listitem><
para>Sets the PAM service
name to set up a session as. If set
the executed process will be
registered as a PAM session under the
specified service name. This is only
useful in conjunction with the
<
varname>User=</
varname> setting. If
not set no PAM session will be opened
for the executed processes. See
<
citerefentry><
refentrytitle>pam</
refentrytitle><
manvolnum>8</
manvolnum></
citerefentry>
for details.</
para></
listitem>
<
term><
varname>TCPWrapName=</
varname></
term>
<
listitem><
para>If this is a
socket-activated service this sets the
tcpwrap service name to check the
permission for the current connection
with. This is only useful in
conjunction with socket-activated
services, and stream sockets (TCP) in
particular. It has no effect on other
on processes unrelated to socket-based
activation. If the tcpwrap
verification fails daemon start-up
will fail and the connection is
<
citerefentry><
refentrytitle>tcpd</
refentrytitle><
manvolnum>8</
manvolnum></
citerefentry>
for details. Note that this option may
be used to do access control checks
only. Shell commands and commands
<
citerefentry><
refentrytitle>hosts_options</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>
are not supported.</
para></
listitem>
<
term><
varname>CapabilityBoundingSet=</
varname></
term>
<
listitem><
para>Controls which
capabilities to include in the
capability bounding set for the
<
citerefentry><
refentrytitle>capabilities</
refentrytitle><
manvolnum>7</
manvolnum></
citerefentry>
for details. Takes a whitespace
separated list of capability names as
<
citerefentry><
refentrytitle>cap_from_name</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>,
e.g. <
literal>CAP_SYS_ADMIN
CAP_SYS_PTRACE</
literal>.
Capabilities listed will be included
in the bounding set, all others are
removed. If the list of capabilities
is prefixed with <
literal>~</
literal>
all but the listed capabilities will
be included, the effect of the
assignment inverted. Note that this
option also affects the respective
capabilities in the effective,
permitted and inheritable capability
<
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>
<
term><
varname>SecureBits=</
varname></
term>
<
listitem><
para>Controls the secure
bits set for the executed process. See
<
citerefentry><
refentrytitle>capabilities</
refentrytitle><
manvolnum>7</
manvolnum></
citerefentry>
for details. Takes a list of strings:
<
option>keep-caps</
option>,
<
option>keep-caps-locked</
option>,
<
option>no-setuid-fixup</
option>,
<
option>no-setuid-fixup-locked</
option>,
<
option>noroot</
option>
and/
or <
option>noroot-locked</
option>. This
option may appear more than once in
which case the secure bits are
ORed. If the empty string is assigned
to this option the bits are reset to
<
term><
varname>Capabilities=</
varname></
term>
<
listitem><
para>Controls the
<
citerefentry><
refentrytitle>capabilities</
refentrytitle><
manvolnum>7</
manvolnum></
citerefentry>
set for the executed process. Take a
capability string describing the
effective, permitted and inherited
capability sets as documented in
<
citerefentry><
refentrytitle>cap_from_text</
refentrytitle><
manvolnum>3</
manvolnum></
citerefentry>.
Note that these capability sets are
usually influenced by the capabilities
attached to the executed file. Due to
<
varname>CapabilityBoundingSet=</
varname>
is probably the much more useful
setting.</
para></
listitem>
<
term><
varname>ControlGroup=</
varname></
term>
<
listitem><
para>Controls the control
groups the executed processes shall be
space-separated list of cgroup
identifiers. A cgroup identifier is
<
filename noindex='true'>cpu:/
foo/
bar</
filename>,
where "cpu" indicates the kernel
control group controller used, and
<
filename noindex='true'>/
foo/
bar</
filename> is the
control group path. The controller
name and ":" may be omitted in which
case the named systemd control group
hierarchy is implied. Alternatively,
the path and ":" may be omitted, in
which case the default control group
path for this unit is implied.</
para>
<
para>This option may be used to place
executed processes in arbitrary groups
in arbitrary hierarchies -- which may
then be externally configured with
additional execution limits. By
default systemd will place all
executed processes in separate
per-unit control groups (named after
the unit) in the systemd named
hierarchy. This option is primarily
intended to place executed processes
in specific paths in specific kernel
controller hierarchies. It is not
recommended to manipulate the service
control group path in the private
(
i.e. <
literal>name=systemd</
literal>),
and doing this might result in
undefined behaviour. For details about
control groups see <
ulink <
para>This option may appear more than
once, in which case the list of
control group assignments is
merged. If the same hierarchy gets two
different paths assigned only the
later setting will take effect. If the
empty string is assigned to this
option the list of control group
assignments is reset, all previous
<
para>Note that the list of control
group assignments of a unit is
extended implicitly based on the
<
varname>DefaultControllers=</
varname>
<
citerefentry><
refentrytitle>
systemd-system.conf</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
varname>ControlGroup=</
varname>
setting for a specific controller
takes precedence.</
para></
listitem>
<
term><
varname>ControlGroupModify=</
varname></
term>
<
listitem><
para>Takes a boolean
argument. If true, the control groups
created for this unit will be owned by
<
varname>User=</
varname> (and the
appropriate group), and
he/
she can create
subgroups as well as add processes to
the group.</
para></
listitem>
<
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
<
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</
literal> refers to a
<
literal>shares</
literal> to the
attribute name), and the attribute
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
<
literal>ControlGroup=</
literal>
option) then the unit will be added to
the controller and the default unit
cgroup path is implied. Thus, using
<
varname>ControlGroupAttribute=</
varname>
is in most cases sufficient to make
use of control group enforcements,
<
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
option may appear more than once, in
order to set multiple control group
attributes. If this option is used
multiple times for the same cgroup
attribute only the later setting takes
effect. If the empty string is
assigned to this option the list of
attributes is reset, all previous
cgroup attribute settings have no
effect, including those done with
<
varname>CPUShares=</
varname>,
<
varname>MemoryLimit=</
varname>,
<
varname>MemorySoftLimit</
varname>,
<
varname>DeviceAllow=</
varname>,
<
varname>DeviceDeny=</
varname>,
<
varname>BlockIOWeight=</
varname>,
<
varname>BlockIOReadBandwidth=</
varname>,
<
varname>BlockIOWriteBandwidth=</
varname>.
<
term><
varname>CPUShares=</
varname></
term>
<
listitem><
para>Assign the specified
overall CPU time shares to the
processes executed. Takes an integer
group attribute, which defaults to
1024. For details about this control
group attribute see <
ulink <
term><
varname>MemoryLimit=</
varname></
term>
<
term><
varname>MemorySoftLimit=</
varname></
term>
<
listitem><
para>Limit the overall memory usage
of the executed processes to a certain
size. Takes a memory size in bytes. If
the value is suffixed with K, M, G or
T the specified memory size is parsed
as Kilobytes, Megabytes, Gigabytes,
or Terabytes (to the base
1024), respectively. This controls the
control group attributes. For details
about these control group attributes
<
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
followed by a combination of r, w, m
to control reading, writing, or
creating of the specific device node
by the unit, respectively. This controls the
control group attributes. For details
about these control group attributes
<
term><
varname>BlockIOWeight=</
varname></
term>
<
listitem><
para>Set the default or
per-device overall block IO weight
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
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
<
term><
varname>BlockIOReadBandwidth=</
varname></
term>
<
term><
varname>BlockIOWriteBandwidth=</
varname></
term>
<
listitem><
para>Set the per-device
overall block IO bandwidth limit for
the executed processes. Takes a space
separated pair of a file path and a
bandwidth value (in bytes per second)
to specify the device specific
bandwidth. The file path may be
specified as path to a block device
node or as any other file in which
case the backing block device of the
file system of the file is determined.
If the bandwidth is suffixed with K, M,
G, or T the specified bandwidth is
parsed as Kilobytes, Megabytes,
Gigabytes, or Terabytes, respectively (Example:
control group attributes. Use this
option multiple times to set bandwidth
limits for multiple devices. For
details about these control group
<
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
hierarchy. Each setting takes a
space-separated list of absolute
directory paths. Directories listed in
<
varname>ReadWriteDirectories=</
varname>
are accessible from within the
namespace with the same access rights
as from outside. Directories listed in
<
varname>ReadOnlyDirectories=</
varname>
are accessible for reading only,
writing will be refused even if the
usual file access controls would
permit this. Directories listed in
<
varname>InaccessibleDirectories=</
varname>
will be made inaccessible for
processes inside the namespace. Note
that restricting access with these
options does not extend to submounts
of a directory. You must list
submounts separately in these settings
to ensure the same limited
access. These options may be specified
more than once in which case all
directories listed will have limited
access from within the namespace. If
the empty string is assigned to this
option the specific list is reset, and
all prior assignments have no
effect.</
para></
listitem>
<
term><
varname>PrivateTmp=</
varname></
term>
<
listitem><
para>Takes a boolean
argument. If true sets up a new file
system namespace for the executed
processes and mounts private
<
filename>/tmp</
filename> and
<
filename>/
var/
tmp</
filename> directories
inside it, that are not shared by
namespace. This is useful to secure
access to temporary files of the
process, but makes sharing between
<
filename>/tmp</
filename> or
impossible. All temporary data created
by service will be removed after service
<
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
<
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
<
term><
varname>MountFlags=</
varname></
term>
<
listitem><
para>Takes a mount
<
option>slave</
option> or
<
option>private</
option>, which
control whether the file system
namespace set up for this unit's
processes will receive or propagate
<
citerefentry><
refentrytitle>mount</
refentrytitle><
manvolnum>2</
manvolnum></
citerefentry>
<
option>shared</
option>.</
para></
listitem>
<
term><
varname>UtmpIdentifier=</
varname></
term>
<
listitem><
para>Takes a four
character identifier string for an
should only be set for services such
as <
command>getty</
command>
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
entries are created or cleaned up for
this service.</
para></
listitem>
<
term><
varname>IgnoreSIGPIPE=</
varname></
term>
<
listitem><
para>Takes a boolean
argument. If true causes SIGPIPE to be
process. Defaults to true, since
SIGPIPE generally is useful only in
shell pipelines.</
para></
listitem>
<
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>
<
term><
varname>SystemCallFilter=</
varname></
term>
<
listitem><
para>Takes a space
separated list of system call
names. If this setting is used all
system calls executed by the unit
process except for the listed ones
will result in immediate process
termination with the SIGSYS signal
(whitelisting). If the first character
of the list is <
literal>~</
literal>
the effect is inverted: only the
listed system calls will result in
immediate process termination
(blacklisting). If this option is used
<
varname>NoNewPrivileges=yes</
varname>
is implied. This feature makes use of
the Secure Computing Mode 2 interfaces
of the kernel ('seccomp filtering')
and is useful for enforcing a minimal
sandboxing environment. Note that the
<
function>execve</
function>,
<
function>rt_sigreturn</
function>,
<
function>sigreturn</
function>,
<
function>exit_group</
function>,
<
function>exit</
function> system calls
are implicitly whitelisted and don't
need to be listed explicitly. This
option may be specified more than once
in which case the filter masks are
merged. If the empty string is
assigned the filter is reset, all
prior assignments will have no
effect.</
para></
listitem>
<
citerefentry><
refentrytitle>systemd</
refentrytitle><
manvolnum>1</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>systemctl</
refentrytitle><
manvolnum>8</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>journalctl</
refentrytitle><
manvolnum>8</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.unit</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.service</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.socket</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.swap</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.mount</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.kill</
refentrytitle><
manvolnum>5</
manvolnum></
citerefentry>,
<
citerefentry><
refentrytitle>
systemd.directives</
refentrytitle><
manvolnum>7</
manvolnum></
citerefentry>