<listitem><para>Controls the CPU
affinity of the executed
processes. Takes a space-separated
- list of CPU indexes. This option may
+ list of CPU indices. This option may
be specified more than once in which
case the specificed CPU affinity masks
are merged. If the empty string is
for the assignment.</para>
<para>Example:
- <programlisting>Environment="VAR1=word1 word2" VAR2=word3 "VAR3=word 5 6"</programlisting>
+ <programlisting>Environment="VAR1=word1 word2" VAR2=word3 "VAR3=$word 5 6"</programlisting>
gives three variables <literal>VAR1</literal>,
- <literal>VAR2</literal>, <literal>VAR3</literal>.
+ <literal>VAR2</literal>, <literal>VAR3</literal>
+ with the values <literal>word1 word2</literal>,
+ <literal>word3</literal>, <literal>$word 5 6</literal>.
</para>
<para>
<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
+ descriptor 2 (standard error) of the
+ executed processes is connected to.
+ The available options are identical to
those of
<varname>StandardOutput=</varname>,
with one exception: if set to
<varlistentry>
<term><varname>TTYPath=</varname></term>
<listitem><para>Sets the terminal
- device node to use if standard input,
- output or stderr are connected to a
+ 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>
system namespace for the executed
processes and mounts private
<filename>/tmp</filename> and
- <filename>/var/tmp</filename> directories
- inside it, that are not shared by
- processes outside of the
+ <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
<filename>/tmp</filename> or
<filename>/var/tmp</filename>
impossible. All temporary data created
- by service will be removed after service
- is stopped. Defaults to
- false.</para></listitem>
+ by service will be removed after
+ the service is stopped. Defaults to
+ false. Note that 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.</para></listitem>
</varlistentry>
<varlistentry>
available to the executed process.
This is useful to securely turn off
network access by the executed
+ process. Defaults to false. Note that
+ 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.</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> 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.</para></listitem>
</varlistentry>
this service.</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 autorize the transition. This
+ directive is ignored if SELinux is
+ disabled. If prefixed by
+ <literal>-</literal>, all errors will
+ be ignored. See
+ <citerefentry><refentrytitle>setexeccon</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for details.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>IgnoreSIGPIPE=</varname></term>
list of system call
names. If this setting is used, all
system calls executed by the unit
- process except for the listed ones
+ processes except for the listed ones
will result in immediate process
termination with the
<constant>SIGSYS</constant> signal
merged. If the empty string is
assigned, the filter is reset, all
prior assignments will have no
- effect.</para></listitem>
+ 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
+ <literal>EPERM</literal>,
+ <literal>EACCES</literal> or
+ <literal>EUCLEAN</literal>. 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
+ <literal>x86</literal>,
+ <literal>x86-64</literal>,
+ <literal>x32</literal>,
+ <literal>arm</literal> as well as the
+ special identifier
+ <literal>native</literal>. 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
+ <literal>native</literal> identifier
+ implicitly maps to the native
+ architecture of the system (or more
+ strictly: to the architecture the
+ system manager is compiled for). Note
+ that setting this option to a
+ non-empty list implies that
+ <literal>native</literal> 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>
</variablelist>
<listitem><para>User name (twice), home
directory, and the login shell.
- Set for the units which
+ The variables are set for the units that
have <varname>User=</varname> set,
which includes user
<command>systemd</command> instances.
<term><varname>$XDG_VTNR</varname></term>
<listitem><para>The identifier of the
- session, and the seat name, and
+ session, the seat name, and
virtual terminal of the session. Set
by
<citerefentry><refentrytitle>pam_systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>
for login sessions.
<varname>$XDG_SEAT</varname> and
- <varname>$XDG_VTNR</varname> will be
- only set when attached to a seat and a
+ <varname>$XDG_VTNR</varname> will
+ only be set when attached to a seat and a
tty.</para></listitem>
</varlistentry>
~ianmdlvl / elogind.git / blobdiff