</refsect1>
<refsect1>
- <title>Automatic Dependencies</title>
-
- <para>A few execution parameters result in additional, automatic
- dependencies to be added.</para>
-
- <para>Units with <varname>WorkingDirectory=</varname>, <varname>RootDirectory=</varname> or
- <varname>RootImage=</varname> set automatically gain dependencies of type <varname>Requires=</varname> and
- <varname>After=</varname> on all mount units required to access the specified paths. This is equivalent to having
- them listed explicitly in <varname>RequiresMountsFor=</varname>.</para>
-
- <para>Similar, units with <varname>PrivateTmp=</varname> enabled automatically get mount unit dependencies for all
- mounts required to access <filename>/tmp</filename> and <filename>/var/tmp</filename>. They will also gain an
- automatic <varname>After=</varname> dependency on
- <citerefentry><refentrytitle>systemd-tmpfiles-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
-
- <para>Units whose standard output or error output is connected to <option>journal</option>, <option>syslog</option>
- or <option>kmsg</option> (or their combinations with console output, see below) automatically acquire dependencies
- of type <varname>After=</varname> on <filename>systemd-journald.socket</filename>.</para>
+ <title>Implicit Dependencies</title>
+
+ <para>A few execution parameters result in additional, automatic dependencies to be added:</para>
+
+ <itemizedlist>
+ <listitem><para>Units with <varname>WorkingDirectory=</varname>, <varname>RootDirectory=</varname>, <varname>RootImage=</varname>,
+ <varname>RuntimeDirectory=</varname>, <varname>StateDirectory=</varname>, <varname>CacheDirectory=</varname>,
+ <varname>LogsDirectory=</varname> or <varname>ConfigurationDirectory=</varname> set automatically gain dependencies
+ of type <varname>Requires=</varname> and <varname>After=</varname> on all mount units required to access the specified paths.
+ This is equivalent to having them listed explicitly in <varname>RequiresMountsFor=</varname>.</para></listitem>
+
+ <listitem><para>Similar, units with <varname>PrivateTmp=</varname> enabled automatically get mount unit dependencies for all
+ mounts required to access <filename>/tmp</filename> and <filename>/var/tmp</filename>. They will also gain an
+ automatic <varname>After=</varname> dependency on
+ <citerefentry><refentrytitle>systemd-tmpfiles-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para></listitem>
+
+ <listitem><para>Units whose standard output or error output is connected to <option>journal</option>, <option>syslog</option>
+ or <option>kmsg</option> (or their combinations with console output, see below) automatically acquire dependencies
+ of type <varname>After=</varname> on <filename>systemd-journald.socket</filename>.</para></listitem>
+ </itemizedlist>
</refsect1>
+ <!-- We don't have any default dependency here. -->
+
<refsect1>
<title>Options</title>
enabled for a unit, the name of the dynamic user/group is implicitly derived from the unit name. If the unit
name without the type suffix qualifies as valid user name it is used directly, otherwise a name incorporating a
hash of it is used. If a statically allocated user or group of the configured name already exists, it is used
- and no dynamic user/group is allocated. Dynamic users/groups are allocated from the UID/GID range
+ and no dynamic user/group is allocated. Note that if <varname>User=</varname> is specified and the static group
+ with the name exists, then it is required that the static user with the name already exists. Similarly,
+ if <varname>Group=</varname> is specified and the static user with the name exists, then it is required that
+ the static group with the name already exists. Dynamic users/groups are allocated from the UID/GID range
61184…65519. It is recommended to avoid this range for regular system or login users. At any point in time
each UID/GID from this range is only assigned to zero or one dynamically allocated users/groups in
use. However, UID/GIDs are recycled after a unit is terminated. Care should be taken that any processes running
cannot leave files around after unit termination. Moreover <varname>ProtectSystem=strict</varname> and
<varname>ProtectHome=read-only</varname> are implied, thus prohibiting the service to write to arbitrary file
system locations. In order to allow the service to write to certain directories, they have to be whitelisted
- using <varname>ReadWritePaths=</varname>, but care must be taken so that UID/GID recycling doesn't
- create security issues involving files created by the service. Use <varname>RuntimeDirectory=</varname> (see
- below) in order to assign a writable runtime directory to a service, owned by the dynamic user/group and
- removed automatically when the unit is terminated. Defaults to off.</para></listitem>
+ using <varname>ReadWritePaths=</varname>, but care must be taken so that UID/GID recycling doesn't create
+ security issues involving files created by the service. Use <varname>RuntimeDirectory=</varname> (see below) in
+ order to assign a writable runtime directory to a service, owned by the dynamic user/group and removed
+ automatically when the unit is terminated. Use <varname>StateDirectory=</varname>,
+ <varname>CacheDirectory=</varname> and <varname>LogsDirectory=</varname> in order to assign a set of writable
+ directories for specific purposes to the service in a way that they are protected from vulnerabilities due to
+ UID reuse (see below). Defaults to off.</para></listitem>
</varlistentry>
<varlistentry>
<varlistentry>
<term><varname>PassEnvironment=</varname></term>
- <listitem><para>Pass environment variables from the systemd system
- manager to executed processes. Takes a space-separated list of variable
- names. This option may be specified more than once, in which case all
- listed variables will be set. If the empty string is assigned to this
- option, the list of environment variables is reset, all prior
- assignments have no effect. Variables that are not set in the system
- manager will not be passed and will be silently ignored.</para>
+ <listitem><para>Pass environment variables set for the system service manager to executed processes. Takes a
+ space-separated list of variable names. This option may be specified more than once, in which case all listed
+ variables will be passed. If the empty string is assigned to this option, the list of environment variables to
+ pass is reset, all prior assignments have no effect. Variables specified that are not set for the system
+ manager will not be passed and will be silently ignored. Note that this option is only relevant for the system
+ service manager, as system services by default do not automatically inherit any environment variables set for
+ the service manager itself. However, in case of the user service manager all environment variables are passed
+ to the executed processes anyway, hence this option is without effect for the user service manager.</para>
- <para>Variables passed from this setting are overridden by those passed
- from <varname>Environment=</varname> or
- <varname>EnvironmentFile=</varname>.</para>
+ <para>Variables set for invoked processes due to this setting are subject to being overridden by those
+ configured with <varname>Environment=</varname> or <varname>EnvironmentFile=</varname>.</para>
<para>Example:
<programlisting>PassEnvironment=VAR1 VAR2 VAR3</programlisting>
for details about environment variables.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>UnsetEnvironment=</varname></term>
+
+ <listitem><para>Explicitly unset environment variable assignments that would normally be passed from the
+ service manager to invoked processes of this unit. Takes a space-separated list of variable names or variable
+ assignments. This option may be specified more than once, in which case all listed variables/assignments will
+ be unset. If the empty string is assigned to this option, the list of environment variables/assignments to
+ unset is reset. If a variable assignment is specified (that is: a variable name, followed by
+ <literal>=</literal>, followed by its value), then any environment variable matching this precise assignment is
+ removed. If a variable name is specified (that is a variable name without any following <literal>=</literal> or
+ value), then any assignment matching the variable name, regardless of its value is removed. Note that the
+ effect of <varname>UnsetEnvironment=</varname> is applied as final step when the environment list passed to
+ executed processes is compiled. That means it may undo assignments from any configuration source, including
+ assignments made through <varname>Environment=</varname> or <varname>EnvironmentFile=</varname>, inherited from
+ the system manager's global set of environment variables, inherited via <varname>PassEnvironment=</varname>,
+ set by the service manager itself (such as <varname>$NOTIFY_SOCKET</varname> and such), or set by a PAM module
+ (in case <varname>PAMName=</varname> is used).</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>StandardInput=</varname></term>
<listitem><para>Controls where file descriptor 0 (STDIN) of
<para>If the standard output (or error output, see below) of a unit is connected to the journal, syslog or the
kernel log buffer, the unit will implicitly gain a dependency of type <varname>After=</varname> on
- <filename>systemd-journald.socket</filename> (also see the automatic dependencies section above).</para>
+ <filename>systemd-journald.socket</filename> (also see the "Implicit Dependencies" section above). Also note
+ that in this case stdout (or stderr, see below) will be an <constant>AF_UNIX</constant> stream socket, and not
+ a pipe or FIFO that can be re-opened. This means when executing shell scripts the construct <command>echo
+ "hello" > /dev/stderr</command> for writing text to stderr will not work. To mitigate this use the construct
+ <command>echo "hello" >&2</command> instead, which is mostly equivalent and avoids this pitfall.</para>
<para>This setting defaults to the value set with
- <option>DefaultStandardOutput=</option> in
+ <varname>DefaultStandardOutput=</varname> in
<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
which defaults to <option>journal</option>. Note that setting
this parameter might result in additional dependencies to be
- added to the unit (see above).</para></listitem>
+ added to the unit (see above).</para>
+ </listitem>
</varlistentry>
<varlistentry>
<literal>stderr</literal>.</para>
<para>This setting defaults to the value set with
- <option>DefaultStandardError=</option> in
+ <varname>DefaultStandardError=</varname> in
<citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
which defaults to <option>inherit</option>. Note that setting
this parameter might result in additional dependencies to be
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>
+ <listitem><para>Sets the process name ("<command>syslog</command> tag") 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>journal</option>, <option>syslog</option> or <option>kmsg</option> (or to the same settings in
+ combination with <option>+console</option>) and only applies to log messages written to stdout or
+ stderr.</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
+ <listitem><para>Sets the <command>syslog</command> facility identifier to use when logging. 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>
+ for details. This option is only useful when <varname>StandardOutput=</varname> or
+ <varname>StandardError=</varname> are set to <option>journal</option>, <option>syslog</option> or
+ <option>kmsg</option> (or to the same settings in combination with <option>+console</option>), and only applies
+ to log messages written to stdout or stderr. 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>.
+ <listitem><para>The default <command>syslog</command> log level to use when logging to the logging system 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>journal</option>, <option>syslog</option> or
+ <option>kmsg</option> (or to the same settings in combination with <option>+console</option>), and only applies
+ to log messages written to stdout or stderr. Note that individual lines output by executed processes may 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>
+ 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>
+ <listitem><para>Takes a boolean argument. If true and <varname>StandardOutput=</varname> or
+ <varname>StandardError=</varname> are set to <option>journal</option>, <option>syslog</option> or
+ <option>kmsg</option> (or to the same settings in combination with <option>+console</option>), log lines
+ written by the executed process that are prefixed with a log level will be processed 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. This only applies to log messages written to stdout or stderr. For details
+ about this prefixing see
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Defaults to
+ true.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>LogLevelMax=</varname></term>
+ <listitem><para>Configures filtering by log level of log messages generated by this unit. Takes a
+ <command>syslog</command> log level, one of <option>emerg</option> (lowest log level, only highest priority
+ messages), <option>alert</option>, <option>crit</option>, <option>err</option>, <option>warning</option>,
+ <option>notice</option>, <option>info</option>, <option>debug</option> (highest log level, also lowest priority
+ messages). See <citerefentry
+ project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> for
+ details. By default no filtering is applied (i.e. the default maximum log level is <option>debug</option>). Use
+ this option to configure the logging system to drop log messages of a specific service above the specified
+ level. For example, set <varname>LogLevelMax=</varname><option>info</option> in order to turn off debug logging
+ of a particularly chatty unit. Note that the the configured level is applied to any log messages written by any
+ of the processes belonging to this unit, sent via any supported logging protocol. The filtering is applied
+ early in the logging pipeline, before any kind of further processing is done. Moreover, messages which pass
+ through this filter successfully might still be dropped by filters applied at a later stage in the logging
+ subsystem. For example, <varname>MaxLevelStore=</varname> configured in
+ <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry> might
+ prohibit messages of higher log levels to be stored on disk, even though the per-unit
+ <varname>LogLevelMax=</varname> permitted it to be processed.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>LogExtraFields=</varname></term>
+ <listitem><para>Configures additional log metadata fields to include in all log records generated by processes
+ associated with this unit. This setting takes one or more journal field assignments in the format
+ <literal>FIELD=VALUE</literal> separated by whitespace. See
+ <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
+ details on the journal field concept. Even though the underlying journal implementation permits binary field
+ values, this setting accepts only valid UTF-8 values. To include space characters in a journal field value,
+ enclose the assignment in double quotes ("). The usual specifiers are expanded in all assignments (see
+ below). Note that this setting is not only useful for attaching additional metadata to log records of a unit,
+ but given that all fields and values are indexed may also be used to implement cross-unit log record
+ matching. Assign an empty string to reset the list.</para></listitem>
</varlistentry>
<varlistentry>
<citerefentry><refentrytitle>setrlimit</refentrytitle><manvolnum>2</manvolnum></citerefentry> for details on
the resource limit concept. Resource limits may be specified in two formats: either as single value to set a
specific soft and hard limit to the same value, or as colon-separated pair <option>soft:hard</option> to set
- both limits individually (e.g. <literal>LimitAS=4G:16G</literal>). Use the string <varname>infinity</varname>
+ both limits individually (e.g. <literal>LimitAS=4G:16G</literal>). Use the string <option>infinity</option>
to configure no limit on a specific resource. The multiplicative suffixes K, M, G, T, P and E (to the base
1024) may be used for resource limits measured in bytes (e.g. LimitAS=16G). For the limits referring to time
values, the usual time units ms, s, min, h and so on may be used (see
<para>Note that for each unit making use of this option a PAM session handler process will be maintained as
part of the unit and stays around as long as the unit is active, to ensure that appropriate actions can be
taken when the unit and hence the PAM session terminates. This process is named <literal>(sd-pam)</literal> and
- is an immediate child process of the unit's main process.</para></listitem>
+ is an immediate child process of the unit's main process.</para>
+
+ <para>Note that when this option is used for a unit it is very likely (depending on PAM configuration) that the
+ main unit process will be migrated to its own session scope unit when it is activated. This process will hence
+ be associated with two units: the unit it was originally started from (and for which
+ <varname>PAMName=</varname> was configured), and the session scope unit. Any child processes of that process
+ will however be associated with the session scope unit only. This has implications when used in combination
+ with <varname>NotifyAccess=</varname><option>all</option>, as these child processes will not be able to affect
+ changes in the original unit through notification messages. These messages will be considered belonging to the
+ session scope unit and not the original unit. It is hence not recommended to use <varname>PAMName=</varname> in
+ combination with <varname>NotifyAccess=</varname><option>all</option>.</para>
+ </listitem>
</varlistentry>
<varlistentry>
inverted. Note that this option also affects the respective capabilities in the effective, permitted and
inheritable capability sets. 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
+ once, in which case the bounding sets are merged by <constant>AND</constant>, or by <constant>OR</constant>
+ if the lines are prefixed with <literal>~</literal> (see below). 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. This does not affect commands prefixed with
- <literal>+</literal>.</para></listitem>
+ <literal>+</literal>.</para>
+
+ <para>Example: if a unit has the following,
+ <programlisting>CapabilityBoundingSet=CAP_A CAP_B
+CapabilityBoundingSet=CAP_B CAP_C</programlisting>
+ then <constant>CAP_A</constant>, <constant>CAP_B</constant>, and <constant>CAP_C</constant> are set.
+ If the second line is prefixed with <literal>~</literal>, e.g.,
+ <programlisting>CapabilityBoundingSet=CAP_A CAP_B
+CapabilityBoundingSet=~CAP_B CAP_C</programlisting>
+ then, only <constant>CAP_A</constant> is set.</para></listitem>
</varlistentry>
<varlistentry>
<listitem><para>Controls which capabilities to include in the ambient capability set for the executed
process. Takes a whitespace-separated list of capability names, e.g. <constant>CAP_SYS_ADMIN</constant>,
<constant>CAP_DAC_OVERRIDE</constant>, <constant>CAP_SYS_PTRACE</constant>. This option may appear more than
- once in which case the ambient capability sets are merged. If the list of capabilities is prefixed with
+ once in which case the ambient capability sets are merged (see the above examples in
+ <varname>CapabilityBoundingSet=</varname>). If the list of capabilities is prefixed with
<literal>~</literal>, all but the listed capabilities will be included, the effect of the assignment
inverted. If the empty string is assigned to this option, the ambient capability set is reset to the empty
capability set, and all prior settings have no effect. If set to <literal>~</literal> (without any further
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, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant>
+ (blacklisting). Blacklisted system calls and system call groups may optionally be suffixed with a colon
+ (<literal>:</literal>) and <literal>errno</literal> error number (between 0 and 4095) or errno name such as
+ <constant>EPERM</constant>, <constant>EACCES</constant> or <constant>EUCLEAN</constant>. This value will be
+ returned when a blacklisted system call is triggered, instead of terminating the processes immediately.
+ This value takes precedence over the one given in <varname>SystemCallErrorNumber=</varname>.
+ If running in user mode, or in system mode, but without the <constant>CAP_SYS_ADMIN</constant>
capability (e.g. setting <varname>User=nobody</varname>), <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>,
</row>
</thead>
<tbody>
+ <row>
+ <entry>@aio</entry>
+ <entry>Asynchronous I/O (<citerefentry project='man-pages'><refentrytitle>io_setup</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>io_submit</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
+ </row>
<row>
<entry>@basic-io</entry>
<entry>System calls for basic I/O: reading, writing, seeking, file descriptor duplication and closing (<citerefentry project='man-pages'><refentrytitle>read</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>write</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
</row>
+ <row>
+ <entry>@chown</entry>
+ <entry>Changing file ownership (<citerefentry project='man-pages'><refentrytitle>chown</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>fchownat</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
+ </row>
<row>
<entry>@clock</entry>
<entry>System calls for changing the system clock (<citerefentry project='man-pages'><refentrytitle>adjtimex</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>settimeofday</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
<entry>@keyring</entry>
<entry>Kernel keyring access (<citerefentry project='man-pages'><refentrytitle>keyctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry>
</row>
+ <row>
+ <entry>@memlock</entry>
+ <entry>Locking of memory into RAM (<citerefentry project='man-pages'><refentrytitle>mlock</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>mlockall</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry>
+ </row>
<row>
<entry>@module</entry>
<entry>Loading and unloading of kernel modules (<citerefentry project='man-pages'><refentrytitle>init_module</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>delete_module</refentrytitle><manvolnum>2</manvolnum></citerefentry> and related calls)</entry>
<entry>@setuid</entry>
<entry>System calls for changing user ID and group ID credentials, (<citerefentry project='man-pages'><refentrytitle>setuid</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>setgid</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>setresuid</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry>
</row>
+ <row>
+ <entry>@signal</entry>
+ <entry>System calls for manipulating and handling process signals (<citerefentry project='man-pages'><refentrytitle>signal</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>sigprocmask</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry>
+ </row>
<row>
<entry>@swap</entry>
<entry>System calls for enabling/disabling swap devices (<citerefentry project='man-pages'><refentrytitle>swapon</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>swapoff</refentrytitle><manvolnum>2</manvolnum></citerefentry>)</entry>
</row>
+ <row>
+ <entry>@sync</entry>
+ <entry>Synchronizing files and memory to disk: (<citerefentry project='man-pages'><refentrytitle>fsync</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>msync</refentrytitle><manvolnum>2</manvolnum></citerefentry>, and related calls)</entry>
+ </row>
+ <row>
+ <entry>@timer</entry>
+ <entry>System calls for scheduling operations by time (<citerefentry project='man-pages'><refentrytitle>alarm</refentrytitle><manvolnum>2</manvolnum></citerefentry>, <citerefentry project='man-pages'><refentrytitle>timer_create</refentrytitle><manvolnum>2</manvolnum></citerefentry>, …)</entry>
+ </row>
</tbody>
</tgroup>
</table>
<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>
+ <listitem><para>Takes an <literal>errno</literal> error number (between 1 and 4095) or errno name such as
+ <constant>EPERM</constant>, <constant>EACCES</constant> or <constant>EUCLEAN</constant>, to return when the
+ system call filter configured with <varname>SystemCallFilter=</varname> is triggered, instead of terminating
+ the process immediately. 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>
<varlistentry>
<term><varname>LockPersonality=</varname></term>
- <listitem><para>Locks down the <citerefentry
+ <listitem><para>Takes a boolean argument. If set, locks down the <citerefentry
project='man-pages'><refentrytitle>personality</refentrytitle><manvolnum>2</manvolnum></citerefentry> system
call so that the kernel execution domain may not be changed from the default or the personality selected with
<varname>Personality=</varname> directive. This may be useful to improve security, because odd personality
<varname>NoNewPrivileges=yes</varname> is implied.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>KeyringMode=</varname></term>
+
+ <listitem><para>Controls how the kernel session keyring is set up for the service (see <citerefentry
+ project='man-pages'><refentrytitle>session-keyring</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
+ details on the session keyring). Takes one of <option>inherit</option>, <option>private</option>,
+ <option>shared</option>. If set to <option>inherit</option> no special keyring setup is done, and the kernel's
+ default behaviour is applied. If <option>private</option> is used a new session keyring is allocated when a
+ service process is invoked, and it is not linked up with any user keyring. This is the recommended setting for
+ system services, as this ensures that multiple services running under the same system user ID (in particular
+ the root user) do not share their key material among each other. If <option>shared</option> is used a new
+ session keyring is allocated as for <option>private</option>, but the user keyring of the user configured with
+ <varname>User=</varname> is linked into it, so that keys assigned to the user may be requested by the unit's
+ processes. In this modes multiple units running processes under the same user ID may share key material. Unless
+ <option>inherit</option> is selected the unique invocation ID for the unit (see below) is added as a protected
+ key by the name <literal>invocation_id</literal> to the newly created session keyring. Defaults to
+ <option>private</option> for the system service manager and to <option>inherit</option> for the user service
+ manager.</para></listitem>
+ </varlistentry>
+
<varlistentry>
<term><varname>RuntimeDirectory=</varname></term>
+ <term><varname>StateDirectory=</varname></term>
+ <term><varname>CacheDirectory=</varname></term>
+ <term><varname>LogsDirectory=</varname></term>
+ <term><varname>ConfigurationDirectory=</varname></term>
- <listitem><para>Takes a whitespace-separated list of directory names. The specified directory names must be
- relative, and may not include <literal>.</literal> or <literal>..</literal>. If set, one or more directories
- including their parents 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. The
- lowest subdirectories are removed when the unit is stopped. It is possible to preserve the directories if
- <varname>RuntimeDirectoryPreserve=</varname> is configured to <option>restart</option> or <option>yes</option>.
- The lowest subdirectories will have the access mode specified in <varname>RuntimeDirectoryMode=</varname>,
- and be owned by the user and group specified in <varname>User=</varname> and <varname>Group=</varname>.
- This implies <varname>ReadWritePaths=</varname>, that is, the directories specified
- in this option are accessible with the access mode specified in <varname>RuntimeDirectoryMode=</varname>
- even if <varname>ProtectSystem=</varname> is set to <option>strict</option>.
- Use this to manage one or more runtime directories of the unit and bind their
- lifetime to the daemon runtime. This is particularly useful for unprivileged daemons that cannot create
+ <listitem><para>These options take a whitespace-separated list of directory names. The specified directory
+ names must be relative, and may not include <literal>.</literal> or <literal>..</literal>. If set, one or more
+ directories by the specified names will be created (including their parents) below <filename>/run</filename>
+ (or <varname>$XDG_RUNTIME_DIR</varname> for user services), <filename>/var/lib</filename> (or
+ <varname>$XDG_CONFIG_HOME</varname> for user services), <filename>/var/cache</filename> (or
+ <varname>$XDG_CACHE_HOME</varname> for user services), <filename>/var/log</filename> (or
+ <varname>$XDG_CONFIG_HOME</varname><filename>/log</filename> for user services), or <filename>/etc</filename>
+ (or <varname>$XDG_CONFIG_HOME</varname> for user services), respectively, when the unit is started.</para>
+
+ <para>In case of <varname>RuntimeDirectory=</varname> the lowest subdirectories are removed when the unit is
+ stopped. It is possible to preserve the specified directories in this case if
+ <varname>RuntimeDirectoryPreserve=</varname> is configured to <option>restart</option> or <option>yes</option>
+ (see below). The directories specified with <varname>StateDirectory=</varname>,
+ <varname>CacheDirectory=</varname>, <varname>LogsDirectory=</varname>,
+ <varname>ConfigurationDirectory=</varname> are not removed when the unit is stopped.</para>
+
+ <para>Except in case of <varname>ConfigurationDirectory=</varname>, the innermost specified directories will be
+ owned by the user and group specified in <varname>User=</varname> and <varname>Group=</varname>. If the
+ specified directories already exist and their owning user or group do not match the configured ones, all files
+ and directories below the specified directories as well as the directories themselves will have their file
+ ownership recursively changed to match what is configured. As an optimization, if the specified directories are
+ already owned by the right user and group, files and directories below of them are left as-is, even if they do
+ not match what is requested. The innermost specified directories will have their access mode adjusted to the
+ what is specified in <varname>RuntimeDirectoryMode=</varname>, <varname>StateDirectoryMode=</varname>,
+ <varname>CacheDirectoryMode=</varname>, <varname>LogsDirectoryMode=</varname> and
+ <varname>ConfigurationDirectoryMode=</varname>.</para>
+
+ <para>These options imply <varname>BindPaths=</varname> for the specified paths. When combined with
+ <varname>RootDirectory=</varname> or <varname>RootImage=</varname> these paths always reside on the host and
+ are mounted from there into the unit's file system namespace.</para>
+
+ <para>If <varname>DynamicUser=</varname> is used in conjunction with <varname>StateDirectory=</varname>,
+ <varname>CacheDirectory=</varname> and <varname>LogsDirectory=</varname> is slightly altered: the directories
+ are created below <filename>/var/lib/private</filename>, <filename>/var/cache/private</filename> and
+ <filename>/var/log/private</filename>, respectively, which are host directories made inaccessible to
+ unprivileged users, which ensures that access to these directories cannot be gained through dynamic user ID
+ recycling. Symbolic links are created to hide this difference in behaviour. Both from perspective of the host
+ and from inside the unit, the relevant directories hence always appear directly below
+ <filename>/var/lib</filename>, <filename>/var/cache</filename> and <filename>/var/log</filename>.</para>
+
+ <para>Use <varname>RuntimeDirectory=</varname> to manage one or more runtime directories for the unit and bind
+ their lifetime to the daemon runtime. 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
+ 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>
<para>Example: if a system service unit has the following,
except <filename>/run/foo</filename> are owned by the user and group specified in <varname>User=</varname> and
<varname>Group=</varname>, and removed when the service is stopped.
</para></listitem>
- </varlistentry>
-
- <varlistentry>
- <term><varname>StateDirectory=</varname></term>
- <term><varname>CacheDirectory=</varname></term>
- <term><varname>LogsDirectory=</varname></term>
- <term><varname>ConfigurationDirectory=</varname></term>
- <listitem><para>Takes a whitespace-separated list of directory names. If set, as similar to
- <varname>RuntimeDirectory=</varname>, one or more directories including their parents by the specified names
- will be created below <filename>/var/lib</filename>, <filename>/var/cache</filename>, <filename>/var/log</filename>,
- or <filename>/etc</filename>, respectively, when the unit is started.
- Unlike <varname>RuntimeDirectory=</varname>, the directories are not removed when the unit is stopped.
- The lowest subdirectories will be owned by the user and group specified in <varname>User=</varname>
- and <varname>Group=</varname>. The options imply <varname>ReadWritePaths=</varname>.
- </para></listitem>
</varlistentry>
<varlistentry>
memory segments as executable are prohibited. Specifically, a system call filter is added that rejects
<citerefentry><refentrytitle>mmap</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls with both
<constant>PROT_EXEC</constant> and <constant>PROT_WRITE</constant> set,
- <citerefentry><refentrytitle>mprotect</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls with
- <constant>PROT_EXEC</constant> set and
+ <citerefentry><refentrytitle>mprotect</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ or <citerefentry><refentrytitle>pkey_mprotect</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+ system calls with <constant>PROT_EXEC</constant> set and
<citerefentry><refentrytitle>shmat</refentrytitle><manvolnum>2</manvolnum></citerefentry> system calls with
<constant>SHM_EXEC</constant> set. Note that this option is incompatible with programs and libraries that
generate program code dynamically at runtime, including JIT execution engines, executable stacks, and code
<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>
+ <para>Processes started by the service manager are executed with an environment variable block assembled from
+ multiple sources. Processes started by the system service manager generally do not inherit environment variables
+ set for the service manager itself (but this may be altered via <varname>PassEnvironment=</varname>), but processes
+ started by the user service manager instances generally do inherit all environment variables set for the service
+ manager itself.</para>
+
+ <para>For each invoked process the list of environment variables set is compiled from the following sources:</para>
+
+ <itemizedlist>
+ <listitem><para>Variables globally configured for the service manager, using the
+ <varname>DefaultEnvironment=</varname> setting in
+ <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>, the kernel command line option <varname>systemd.setenv=</varname> (see
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>) or via
+ <command>systemctl set-environment</command> (see <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>).</para></listitem>
+
+ <listitem><para>Variables defined by the service manager itself (see the list below)</para></listitem>
+
+ <listitem><para>Variables set in the service manager's own environment variable block (subject to <varname>PassEnvironment=</varname> for the system service manager)</para></listitem>
+
+ <listitem><para>Variables set via <varname>Environment=</varname> in the unit file</para></listitem>
+
+ <listitem><para>Variables read from files specified via <varname>EnvironmentFiles=</varname> in the unit file</para></listitem>
+
+ <listitem><para>Variables set by any PAM modules in case <varname>PAMName=</varname> is in effect, cf. <citerefentry project='man-pages'><refentrytitle>pam_env</refentrytitle><manvolnum>8</manvolnum></citerefentry></para></listitem>
+ </itemizedlist>
+
+ <para>If the same environment variables are set by multiple of these sources, the later source — according to the
+ order of the list above — wins. Note that as final step all variables listed in
+ <varname>UnsetEnvironment=</varname> are removed again from the compiled environment variable list, immediately
+ before it is passed to the executed process.</para>
+
+ <para>The following select environment variables are set by the service manager itself for each invoked process:</para>
<variablelist class='environment-variables'>
<varlistentry>
<varname>$JOURNAL_STREAM</varname> is set at all as services might invoke external processes replacing their
standard output or standard error output, without unsetting the environment variable.</para>
+ <para>If both standard output and standard error of the executed processes are connected to the journal via a
+ stream socket, this environment variable will contain information about the standard error stream, as that's
+ usually the preferred destination for log data. (Note that typically the same stream is used for both standard
+ output and standard error, hence very likely the environment variable contains device and inode information
+ matching both stream file descriptors.)</para>
+
<para>This environment variable is primarily useful to allow services to optionally upgrade their used log
protocol to the native journal protocol (using
<citerefentry><refentrytitle>sd_journal_print</refentrytitle><manvolnum>3</manvolnum></citerefentry> and other
<listitem><para>Only defined for the service unit type, this environment variable is passed to all
<varname>ExecStop=</varname> and <varname>ExecStopPost=</varname> processes, and encodes the service
- "result". Currently, the following values are defined: <literal>protocol</literal> (in case of a protocol
- violation; if a service did not take the steps required by its unit configuration), <literal>timeout</literal>
- (in case of an operation timeout), <literal>exit-code</literal> (if a service process exited with a non-zero
- exit code; see <varname>$EXIT_CODE</varname> below for the actual exit code returned), <literal>signal</literal>
- (if a service process was terminated abnormally by a signal; see <varname>$EXIT_CODE</varname> below for the
- actual signal used for the termination), <literal>core-dump</literal> (if a service process terminated
- abnormally and dumped core), <literal>watchdog</literal> (if the watchdog keep-alive ping was enabled for the
- service but it missed the deadline), or <literal>resources</literal> (a catch-all condition in case a system
- operation failed).</para>
+ "result". Currently, the following values are defined:</para>
+
+ <table>
+ <title>Defined <varname>$SERVICE_RESULT</varname> values</title>
+ <tgroup cols='2'>
+ <colspec colname='result'/>
+ <colspec colname='meaning'/>
+ <thead>
+ <row>
+ <entry>Value</entry>
+ <entry>Meaning</entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry><literal>success</literal></entry>
+ <entry>The service ran successfully and exited cleanly.</entry>
+ </row>
+ <row>
+ <entry><literal>protocol</literal></entry>
+ <entry>A protocol violation occurred: the service did not take the steps required by its unit configuration (specifically what is configured in its <varname>Type=</varname> setting).</entry>
+ </row>
+ <row>
+ <entry><literal>timeout</literal></entry>
+ <entry>One of the steps timed out.</entry>
+ </row>
+ <row>
+ <entry><literal>exit-code</literal></entry>
+ <entry>Service process exited with a non-zero exit code; see <varname>$EXIT_CODE</varname> below for the actual exit code returned.</entry>
+ </row>
+ <row>
+ <entry><literal>signal</literal></entry>
+ <entry>A service process was terminated abnormally by a signal, without dumping core. See <varname>$EXIT_CODE</varname> below for the actual signal causing the termination.</entry>
+ </row>
+ <row>
+ <entry><literal>core-dump</literal></entry>
+ <entry>A service process terminated abnormally with a signal and dumped core. See <varname>$EXIT_CODE</varname> below for the signal causing the termination.</entry>
+ </row>
+ <row>
+ <entry><literal>watchdog</literal></entry>
+ <entry>Watchdog keep-alive ping was enabled for the service, but the deadline was missed.</entry>
+ </row>
+ <row>
+ <entry><literal>start-limit-hit</literal></entry>
+ <entry>A start limit was defined for the unit and it was hit, causing the unit to fail to start. See <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>'s <varname>StartLimitIntervalSec=</varname> and <varname>StartLimitBurst=</varname> for details.</entry>
+ </row>
+ <row>
+ <entry><literal>resources</literal></entry>
+ <entry>A catch-all condition in case a system operation failed.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
<para>This environment variable is useful to monitor failure or successful termination of a service. Even
though this variable is available in both <varname>ExecStop=</varname> and <varname>ExecStopPost=</varname>, it
</thead>
<tbody>
+ <row>
+ <entry valign="top"><literal>success</literal></entry>
+ <entry valign="top"><literal>exited</literal></entry>
+ <entry><literal>0</literal></entry>
+ </row>
<row>
<entry morerows="1" valign="top"><literal>protocol</literal></entry>
<entry valign="top">not set</entry>
<entry><literal>exited</literal></entry>
<entry><literal>0</literal></entry>
</row>
-
<row>
<entry morerows="1" valign="top"><literal>timeout</literal></entry>
<entry valign="top"><literal>killed</literal></entry>
<entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal
>3</literal>, …, <literal>255</literal></entry>
</row>
-
<row>
<entry valign="top"><literal>exit-code</literal></entry>
<entry valign="top"><literal>exited</literal></entry>
- <entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal
+ <entry><literal>1</literal>, <literal>2</literal>, <literal
>3</literal>, …, <literal>255</literal></entry>
</row>
-
<row>
<entry valign="top"><literal>signal</literal></entry>
<entry valign="top"><literal>killed</literal></entry>
<entry><literal>HUP</literal>, <literal>INT</literal>, <literal>KILL</literal>, …</entry>
</row>
-
<row>
<entry valign="top"><literal>core-dump</literal></entry>
<entry valign="top"><literal>dumped</literal></entry>
<entry><literal>ABRT</literal>, <literal>SEGV</literal>, <literal>QUIT</literal>, …</entry>
</row>
-
<row>
<entry morerows="2" valign="top"><literal>watchdog</literal></entry>
<entry><literal>dumped</literal></entry>
<entry><literal>0</literal>, <literal>1</literal>, <literal>2</literal>, <literal
>3</literal>, …, <literal>255</literal></entry>
</row>
-
+ <row>
+ <entry><literal>start-limit-hit</literal></entry>
+ <entry>not set</entry>
+ <entry>not set</entry>
+ </row>
<row>
<entry><literal>resources</literal></entry>
<entry>any of the above</entry>
<entry>any of the above</entry>
</row>
-
<row>
- <entry namest="results" nameend="code">Note: the process may be also terminated by a signal not sent by systemd. In particular the process may send an arbitrary signal to itself in a handler for any of the non-maskable signals. Nevertheless, in the <literal>timeout</literal> and <literal>watchdog</literal> rows above only the signals that systemd sends have been included.</entry>
+ <entry namest="results" nameend="status">Note: the process may be also terminated by a signal not sent by systemd. In particular the process may send an arbitrary signal to itself in a handler for any of the non-maskable signals. Nevertheless, in the <literal>timeout</literal> and <literal>watchdog</literal> rows above only the signals that systemd sends have been included. Moreover, using <varname>SuccessExitStatus=</varname> additional exit statuses may be declared to indicate clean termination, which is not reflected by this table.</entry>
</row>
</tbody>
</tgroup>
</listitem>
</varlistentry>
</variablelist>
+ </refsect1>
- <para>Additional variables may be configured by the following
- means: for processes spawned in specific units, use the
- <varname>Environment=</varname>, <varname>EnvironmentFile=</varname>
- and <varname>PassEnvironment=</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>
+ <title>Process exit codes</title>
+
+ <para>When invoking a unit process the service manager possibly fails to apply the execution parameters configured
+ with the settings above. In that case the already created service process will exit with a non-zero exit code
+ before the configured command line is executed. (Or in other words, the child process possibly exits with these
+ error codes, after having been created by the <citerefentry
+ project='man-pages'><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call, but
+ before the matching <citerefentry
+ project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call is
+ called.) Specifically, exit codes defined by the C library, by the LSB specification and by the systemd service
+ manager itself are used.</para>
+
+ <para>The following basic service exit codes are defined by the C library.</para>
+
+ <table>
+ <title>Basic C library exit codes</title>
+ <tgroup cols='3'>
+ <thead>
+ <row>
+ <entry>Exit Code</entry>
+ <entry>Symbolic Name</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>0</entry>
+ <entry><constant>EXIT_SUCCESS</constant></entry>
+ <entry>Generic success code.</entry>
+ </row>
+ <row>
+ <entry>1</entry>
+ <entry><constant>EXIT_FAILURE</constant></entry>
+ <entry>Generic failure or unspecified error.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>The following service exit codes are defined by the <ulink
+ url="https://refspecs.linuxbase.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html">LSB specification
+ </ulink>.
+ </para>
+
+ <table>
+ <title>LSB service exit codes</title>
+ <tgroup cols='3'>
+ <thead>
+ <row>
+ <entry>Exit Code</entry>
+ <entry>Symbolic Name</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>2</entry>
+ <entry><constant>EXIT_INVALIDARGUMENT</constant></entry>
+ <entry>Invalid or excess arguments.</entry>
+ </row>
+ <row>
+ <entry>3</entry>
+ <entry><constant>EXIT_NOTIMPLEMENTED</constant></entry>
+ <entry>Unimplemented feature.</entry>
+ </row>
+ <row>
+ <entry>4</entry>
+ <entry><constant>EXIT_NOPERMISSION</constant></entry>
+ <entry>The user has insufficient privileges.</entry>
+ </row>
+ <row>
+ <entry>5</entry>
+ <entry><constant>EXIT_NOTINSTALLED</constant></entry>
+ <entry>The program is not installed.</entry>
+ </row>
+ <row>
+ <entry>6</entry>
+ <entry><constant>EXIT_NOTCONFIGURED</constant></entry>
+ <entry>The program is not configured.</entry>
+ </row>
+ <row>
+ <entry>7</entry>
+ <entry><constant>EXIT_NOTRUNNING</constant></entry>
+ <entry>The program is not running.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
+
+ <para>
+ The LSB specification suggests that error codes 200 and above are reserved for implementations. Some of them are
+ used by the service manager to indicate problems during process invocation:
+ </para>
+ <table>
+ <title>systemd-specific exit codes</title>
+ <tgroup cols='3'>
+ <thead>
+ <row>
+ <entry>Exit Code</entry>
+ <entry>Symbolic Name</entry>
+ <entry>Description</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry>200</entry>
+ <entry><constant>EXIT_CHDIR</constant></entry>
+ <entry>Changing to the requested working directory failed. See <varname>WorkingDirectory=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>201</entry>
+ <entry><constant>EXIT_NICE</constant></entry>
+ <entry>Failed to set up process scheduling priority (nice level). See <varname>Nice=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>202</entry>
+ <entry><constant>EXIT_FDS</constant></entry>
+ <entry>Failed to close unwanted file descriptors, or to adjust passed file descriptors.</entry>
+ </row>
+ <row>
+ <entry>203</entry>
+ <entry><constant>EXIT_EXEC</constant></entry>
+ <entry>The actual process execution failed (specifically, the <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry> system call). Most likely this is caused by a missing or non-accessible executable file.</entry>
+ </row>
+ <row>
+ <entry>204</entry>
+ <entry><constant>EXIT_MEMORY</constant></entry>
+ <entry>Failed to perform an action due to memory shortage.</entry>
+ </row>
+ <row>
+ <entry>205</entry>
+ <entry><constant>EXIT_LIMITS</constant></entry>
+ <entry>Failed to adjust resource limits. See <varname>LimitCPU=</varname> and related settings above.</entry>
+ </row>
+ <row>
+ <entry>206</entry>
+ <entry><constant>EXIT_OOM_ADJUST</constant></entry>
+ <entry>Failed to adjust the OOM setting. See <varname>OOMScoreAdjust=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>207</entry>
+ <entry><constant>EXIT_SIGNAL_MASK</constant></entry>
+ <entry>Failed to set process signal mask.</entry>
+ </row>
+ <row>
+ <entry>208</entry>
+ <entry><constant>EXIT_STDIN</constant></entry>
+ <entry>Failed to set up standard input. See <varname>StandardInput=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>209</entry>
+ <entry><constant>EXIT_STDOUT</constant></entry>
+ <entry>Failed to set up standard output. See <varname>StandardOutput=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>210</entry>
+ <entry><constant>EXIT_CHROOT</constant></entry>
+ <entry>Failed to change root directory (<citerefentry project='man-pages'><refentrytitle>chroot</refentrytitle><manvolnum>2</manvolnum></citerefentry>). See <varname>RootDirectory=</varname>/<varname>RootImage=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>211</entry>
+ <entry><constant>EXIT_IOPRIO</constant></entry>
+ <entry>Failed to set up IO scheduling priority. See <varname>IOSchedulingClass=</varname>/<varname>IOSchedulingPriority=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>212</entry>
+ <entry><constant>EXIT_TIMERSLACK</constant></entry>
+ <entry>Failed to set up timer slack. See <varname>TimerSlackNSec=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>213</entry>
+ <entry><constant>EXIT_SECUREBITS</constant></entry>
+ <entry>Failed to set process secure bits. See <varname>SecureBits=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>214</entry>
+ <entry><constant>EXIT_SETSCHEDULER</constant></entry>
+ <entry>Failed to set up CPU scheduling. See <varname>CPUSchedulingPolicy=</varname>/<varname>CPUSchedulingPriority=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>215</entry>
+ <entry><constant>EXIT_CPUAFFINITY</constant></entry>
+ <entry>Failed to set up CPU affinity. See <varname>CPUAffinity=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>216</entry>
+ <entry><constant>EXIT_GROUP</constant></entry>
+ <entry>Failed to determine or change group credentials. See <varname>Group=</varname>/<varname>SupplementaryGroups=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>217</entry>
+ <entry><constant>EXIT_USER</constant></entry>
+ <entry>Failed to determine or change user credentials, or to set up user namespacing. See <varname>User=</varname>/<varname>PrivateUsers=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>218</entry>
+ <entry><constant>EXIT_CAPABILITIES</constant></entry>
+ <entry>Failed to drop capabilities, or apply ambient capabilities. See <varname>CapabilityBoundingSet=</varname>/<varname>AmbientCapabilities=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>219</entry>
+ <entry><constant>EXIT_CGROUP</constant></entry>
+ <entry>Setting up the service control group failed.</entry>
+ </row>
+ <row>
+ <entry>220</entry>
+ <entry><constant>EXIT_SETSID</constant></entry>
+ <entry>Failed to create new process session.</entry>
+ </row>
+ <row>
+ <entry>221</entry>
+ <entry><constant>EXIT_CONFIRM</constant></entry>
+ <entry>Execution has been cancelled by the user. See the <varname>systemd.confirm_spawn=</varname> kernel command line setting on <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry> for details.</entry>
+ </row>
+ <row>
+ <entry>222</entry>
+ <entry><constant>EXIT_STDERR</constant></entry>
+ <entry>Failed to set up standard error output. See <varname>StandardError=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>224</entry>
+ <entry><constant>EXIT_PAM</constant></entry>
+ <entry>Failed to set up PAM session. See <varname>PAMName=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>225</entry>
+ <entry><constant>EXIT_NETWORK</constant></entry>
+ <entry>Failed to set up network namespacing. See <varname>PrivateNetwork=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>226</entry>
+ <entry><constant>EXIT_NAMESPACE</constant></entry>
+ <entry>Failed to set up mount namespacing. See <varname>ReadOnlyPaths=</varname> and related settings above.</entry>
+ </row>
+ <row>
+ <entry>227</entry>
+ <entry><constant>EXIT_NO_NEW_PRIVILEGES</constant></entry>
+ <entry>Failed to disable new privileges. See <varname>NoNewPrivileges=yes</varname> above.</entry>
+ </row>
+ <row>
+ <entry>228</entry>
+ <entry><constant>EXIT_SECCOMP</constant></entry>
+ <entry>Failed to apply system call filters. See <varname>SystemCallFilter=</varname> and related settings above.</entry>
+ </row>
+ <row>
+ <entry>229</entry>
+ <entry><constant>EXIT_SELINUX_CONTEXT</constant></entry>
+ <entry>Determining or changing SELinux context failed. See <varname>SELinuxContext=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>230</entry>
+ <entry><constant>EXIT_PERSONALITY</constant></entry>
+ <entry>Failed to set up an execution domain (personality). See <varname>Personality=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>231</entry>
+ <entry><constant>EXIT_APPARMOR_PROFILE</constant></entry>
+ <entry>Failed to prepare changing AppArmor profile. See <varname>AppArmorProfile=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>232</entry>
+ <entry><constant>EXIT_ADDRESS_FAMILIES</constant></entry>
+ <entry>Failed to restrict address families. See <varname>RestrictAddressFamilies=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>233</entry>
+ <entry><constant>EXIT_RUNTIME_DIRECTORY</constant></entry>
+ <entry>Setting up runtime directory failed. See <varname>RuntimeDirectory=</varname> and related settings above.</entry>
+ </row>
+ <row>
+ <entry>235</entry>
+ <entry><constant>EXIT_CHOWN</constant></entry>
+ <entry>Failed to adjust socket ownership. Used for socket units only.</entry>
+ </row>
+ <row>
+ <entry>236</entry>
+ <entry><constant>EXIT_SMACK_PROCESS_LABEL</constant></entry>
+ <entry>Failed to set SMACK label. See <varname>SmackProcessLabel=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>237</entry>
+ <entry><constant>EXIT_KEYRING</constant></entry>
+ <entry>Failed to set up kernel keyring.</entry>
+ </row>
+ <row>
+ <entry>238</entry>
+ <entry><constant>EXIT_STATE_DIRECTORY</constant></entry>
+ <entry>Failed to set up unit's state directory. See <varname>StateDirectory=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>239</entry>
+ <entry><constant>EXIT_CACHE_DIRECTORY</constant></entry>
+ <entry>Failed to set up unit's cache directory. See <varname>CacheDirectory=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>240</entry>
+ <entry><constant>EXIT_LOGS_DIRECTORY</constant></entry>
+ <entry>Failed to set up unit's logging directory. See <varname>LogsDirectory=</varname> above.</entry>
+ </row>
+ <row>
+ <entry>241</entry>
+ <entry><constant>EXIT_CONFIGURATION_DIRECTORY</constant></entry>
+ <entry>Failed to set up unit's configuration directory. See <varname>ConfigurationDirectory=</varname> above.</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
</refsect1>
<refsect1>
projects / thirdparty / systemd.git / blobdiff