chiark / gitweb /
man: document $MAINPID
[elogind.git] / man / systemd.service.xml
index 598e863..3b2a7cf 100644 (file)
@@ -48,7 +48,7 @@
         </refnamediv>
 
         <refsynopsisdiv>
-                <para><filename>systemd.service</filename></para>
+                <para><filename><replaceable>service</replaceable>.service</filename></para>
         </refsynopsisdiv>
 
         <refsect1>
                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                 which define the execution environment the commands
                 are executed in, and in
-                <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+                <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                 which define the way the processes of the service are
-                terminated.</para>
+                terminated, and in
+                <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                which configure resource control settings for the
+                processes of the service.</para>
 
                 <para>Unless <varname>DefaultDependencies=</varname>
                 is set to <option>false</option>, service units will
                 script. This is useful for compatibility with
                 SysV. Note that this compatibility is quite
                 comprehensive but not 100%. For details about the
-                incompatibilities see the <ulink
+                incompatibilities, see the <ulink
                 url="http://www.freedesktop.org/wiki/Software/systemd/Incompatibilities">Incompatibilities
                 with SysV</ulink> document.
                 </para>
                 options specific to the <literal>[Service]</literal>
                 section of service units are the following:</para>
 
-                <variablelist>
+                <variablelist class='unit-directives'>
                         <varlistentry>
                                 <term><varname>Type=</varname></term>
 
 
                                 <para>If set to
                                 <option>simple</option> (the default
-                                value if <varname>BusName=</varname>
-                                is not specified) it is expected that
-                                the process configured with
+                                value if neither
+                                <varname>Type=</varname> nor
+                                <varname>BusName=</varname> are
+                                specified), it is expected that the
+                                process configured with
                                 <varname>ExecStart=</varname> is the
                                 main process of the service. In this
                                 mode, if the process offers
                                 functionality to other processes on
-                                the system its communication channels
+                                the system, its communication channels
                                 should be installed before the daemon
                                 is started up (e.g. sockets set up by
                                 systemd, via socket activation), as
                                 starting follow-up units.</para>
 
                                 <para>If set to
-                                <option>forking</option> it is
+                                <option>forking</option>, it is
                                 expected that the process configured
                                 with <varname>ExecStart=</varname>
                                 will call <function>fork()</function>
                                 as part of its start-up. The parent process is
                                 expected to exit when start-up is
                                 complete and all communication
-                                channels set up. The child continues
+                                channels are set up. The child continues
                                 to run as the main daemon
                                 process. This is the behavior of
                                 traditional UNIX daemons. If this
                                 <varname>PIDFile=</varname> option, so
                                 that systemd can identify the main
                                 process of the daemon. systemd will
-                                proceed starting follow-up units as
-                                soon as the parent process
+                                proceed with starting follow-up units
+                                as soon as the parent process
                                 exits.</para>
 
                                 <para>Behavior of
                                 <option>oneshot</option> is similar
-                                to <option>simple</option>, however
+                                to <option>simple</option>; however,
                                 it is expected that the process has to
                                 exit before systemd starts follow-up
                                 units. <varname>RemainAfterExit=</varname>
 
                                 <para>Behavior of
                                 <option>dbus</option> is similar to
-                                <option>simple</option>, however it is
+                                <option>simple</option>; however, it is
                                 expected that the daemon acquires a
                                 name on the D-Bus bus, as configured
                                 by
                                 <varname>BusName=</varname>. systemd
-                                will proceed starting follow-up units
-                                after the D-Bus bus name has been
+                                will proceed with starting follow-up
+                                units after the D-Bus bus name has been
                                 acquired. Service units with this
                                 option configured implicitly gain
                                 dependencies on the
 
                                 <para>Behavior of
                                 <option>notify</option> is similar to
-                                <option>simple</option>, however it is
+                                <option>simple</option>; however, it is
                                 expected that the daemon sends a
                                 notification message via
                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
-                                or an equivalent call when it finished
-                                starting up. systemd will proceed
+                                or an equivalent call when it has finished
+                                starting up. systemd will proceed with
                                 starting follow-up units after this
                                 notification message has been sent. If
-                                this option is used
+                                this option is used,
                                 <varname>NotifyAccess=</varname> (see
                                 below) should be set to open access to
                                 the notification socket provided by
                                 systemd. If
                                 <varname>NotifyAccess=</varname> is
                                 not set, it will be implicitly set to
-                                <option>main</option>.</para>
+                                <option>main</option>. Note that
+                                currently
+                                <varname>Type=</varname><option>notify</option>
+                                will not work if used in combination with
+                                <varname>PrivateNetwork=</varname><option>yes</option>.</para>
 
                                 <para>Behavior of
                                 <option>idle</option> is very similar
-                                to <option>simple</option>, however
+                                to <option>simple</option>; however,
                                 actual execution of the service
                                 binary is delayed until all jobs are
                                 dispatched. This may be used to avoid
                                 is set and <option>PIDFile=</option>
                                 is unset because for the other types
                                 or with an explicitly configured PID
-                                file the main PID is always known. The
+                                file, the main PID is always known. The
                                 guessing algorithm might come to
                                 incorrect conclusions if a daemon
                                 consists of more than one process. If
-                                the main PID cannot be determined
+                                the main PID cannot be determined,
                                 failure detection and automatic
                                 restarting of a service will not work
                                 reliably. Defaults to
                                 <term><varname>BusName=</varname></term>
 
                                 <listitem><para>Takes a D-Bus bus
-                                name, that this service is reachable
+                                name that this service is reachable
                                 as. This option is mandatory for
                                 services where
                                 <varname>Type=</varname> is set to
                                 <option>dbus</option>, but its use
-                                is otherwise recommended as well if
-                                the process takes a name on the D-Bus
-                                bus.</para>
+                                is otherwise recommended if the process
+                                takes a name on the D-Bus bus.</para>
                                 </listitem>
                         </varlistentry>
 
                                 <term><varname>ExecStart=</varname></term>
                                 <listitem><para>Commands with their
                                 arguments that are executed when this
-                                service is started.
-                                </para>
+                                service is started. For each of the
+                                specified commands, the first argument
+                                must be an absolute and literal path
+                                to an executable.</para>
 
-                                <para>When
+                                <para>When <varname>Type</varname> is
+                                not <option>oneshot</option>, only one
+                                command may be given. When
                                 <varname>Type=oneshot</varname> is
                                 used, more than one command may be
                                 specified. Multiple command lines may
-                                be concatenated in a single directive,
+                                be concatenated in a single directive
                                 by separating them with semicolons
                                 (these semicolons must be passed as
                                 separate words). Alternatively, this
                                 directive may be specified more than
-                                once with the same effect. However,
-                                the latter syntax is not recommended
-                                for compatibility with parsers
-                                suitable for XDG
-                                <filename>.desktop</filename> files.
-                                The commands are invoked one by
-                                one sequentially in the order they
-                                appear in the unit file.
-                                When <varname>Type</varname> is
-                                not <option>oneshot</option>, only one
-                                command may be given. Lone semicolons
-                                may be escaped as
-                                '<literal>\;</literal>'.</para>
+                                once with the same effect.
+                                Lone semicolons may be escaped as
+                                <literal>\;</literal>. If the empty
+                                string is assigned to this option, the
+                                list of commands to start is reset,
+                                prior assignments of this option will
+                                have no effect.</para>
+
+                                <para>Each command line is split on
+                                whitespace, with the first item being
+                                the command to execute, and the
+                                subsequent items being the arguments.
+                                Double quotes ("...") and single
+                                quotes ('...') may be used, in which
+                                case everything until the next
+                                matching quote becomes part of the
+                                same argument. Quotes themselves are
+                                removed after parsing. In addition, a
+                                trailing backslash
+                                (<literal>\</literal>) may be used to
+                                merge lines. This syntax is intended
+                                to be very similar to shell syntax,
+                                but only the meta-characters and
+                                expansions described in the following
+                                paragraphs are understood.
+                                Specifically, redirection using
+                                <literal>&lt;</literal>,
+                                <literal>&lt;&lt;</literal>,
+                                <literal>&gt;</literal>, and
+                                <literal>&gt;&gt;</literal>, pipes
+                                using <literal>|</literal>, and
+                                running programs in the background
+                                using <literal>&amp;</literal>
+                                and <emphasis>other elements of shell
+                                syntax are not supported</emphasis>.
+                                </para>
+
+                                <para>If more than one command is
+                                specified, the commands are invoked
+                                sequentially in the order they appear
+                                in the unit file. If one of the
+                                commands fails (and is not prefixed
+                                with <literal>-</literal>), other lines
+                                are not executed, and the unit is
+                                considered failed.</para>
 
                                 <para>Unless
                                 <varname>Type=forking</varname> is
                                 main process of the daemon.</para>
 
                                 <para>The command line accepts
-                                '<literal>%</literal>' specifiers as
+                                <literal>%</literal> specifiers as
                                 described in
-                                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Note
-                                that the first argument of the command
-                                line (i.e. the program to execute) may
-                                not include specifiers.</para>
+                                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+                                Note that the first argument of the
+                                command line (i.e. the program to
+                                execute) may not include
+                                specifiers.</para>
+
+                                <para>Basic environment variable
+                                substitution is supported. Use
+                                <literal>${FOO}</literal> as part of a
+                                word, or as a word of its own, on the
+                                command line, in which case it will be
+                                replaced by the value of the
+                                environment variable including all
+                                whitespace it contains, resulting in a
+                                single argument. Use
+                                <literal>$FOO</literal> as a separate
+                                word on the command line, in which
+                                case it will be replaced by the value
+                                of the environment variable split at
+                                whitespace, resulting in zero or more
+                                arguments. To pass a literal dollar
+                                sign, use <literal>$$</literal>.
+                                Variables whose value is not known at
+                                expansion time are treated as empty
+                                strings. Note that the first argument
+                                (i.e. the program to execute) may not
+                                be a variable.</para>
+
+                                <para>Variables to be used in this
+                                fashion may be defined through
+                                <varname>Environment=</varname> and
+                                <varname>EnvironmentFile=</varname>.
+                                In addition, variables listed in the
+                                section "Environment variables in
+                                spawned processes" in
+                                <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                                which are considered "static
+                                configuration", may be used (this includes
+                                e.g. <varname>$USER</varname>, but not
+                                <varname>$TERM</varname>).</para>
 
                                 <para>Optionally, if the absolute file
                                 name is prefixed with
-                                '<literal>@</literal>', the second token
+                                <literal>@</literal>, the second token
                                 will be passed as
                                 <literal>argv[0]</literal> to the
                                 executed process, followed by the
                                 further arguments specified. If the
-                                absolute file name is prefixed with
-                                '<literal>-</literal>' an exit code of
+                                absolute filename is prefixed with
+                                <literal>-</literal>, an exit code of
                                 the command normally considered a
                                 failure (i.e. non-zero exit status or
                                 abnormal exit due to signal) is ignored
                                 and considered success. If both
-                                '<literal>-</literal>' and
-                                '<literal>@</literal>' are used they
+                                <literal>-</literal> and
+                                <literal>@</literal> are used, they
                                 can appear in either order.</para>
 
-                                <para>On top of that basic environment
-                                variable substitution is
-                                supported. Use
-                                <literal>${FOO}</literal> as part of a
-                                word, or as a word of its own on the
-                                command line, in which case it will be
-                                replaced by the value of the
-                                environment variable including all
-                                whitespace it contains, resulting in a
-                                single argument.  Use
-                                <literal>$FOO</literal> as a separate
-                                word on the command line, in which
-                                case it will be replaced by the value
-                                of the environment variable split up
-                                at whitespace, resulting in no or more
-                                arguments. Note that the first
-                                argument (i.e. the program to execute)
-                                may not be a variable, and must be a
-                                literal and absolute path
-                                name.</para>
-
                                 <para>Note that this setting does not
                                 directly support shell command
                                 lines. If shell command lines are to
-                                be used they need to be passed
+                                be used, they need to be passed
                                 explicitly to a shell implementation
-                                of some kind. Example:
-                                <literal>ExecStart=/bin/sh -c 'dmesg | tac'</literal></para>
-
-                                <para>For services run by a user
-                                instance of systemd the special
-                                environment variable
-                                <literal>MANAGERPID</literal> is set
-                                to the PID of the systemd
-                                instance.</para>
-                                </listitem>
+                                of some kind. Example:</para>
+                                <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'</programlisting>
+                                <para>Example:</para>
+                                <programlisting>ExecStart=/bin/echo one ; /bin/echo "two two"</programlisting>
+                                <para>This will execute
+                                <command>/bin/echo</command> two
+                                times, each time with one argument:
+                                <literal>one</literal> and
+                                <literal>two two</literal>,
+                                respectively. Because two commands are
+                                specified,
+                                <varname>Type=oneshot</varname> must
+                                be used.</para>
+
+                                <para>Example:</para>
+                                <programlisting>ExecStart=/bin/echo / &gt;/dev/null &amp; \; \
+/bin/ls</programlisting>
+                                <para>This will execute
+                                <command>/bin/echo</command> with five
+                                arguments: <literal>/</literal>,
+                                <literal>&gt;/dev/null</literal>,
+                                <literal>&amp;</literal>,
+                                <literal>;</literal>, and
+                                <literal>/bin/ls</literal>.</para>
+
+                                <para>Example:</para>
+                                <programlisting>Environment="ONE=one" 'TWO=two two'
+ExecStart=/bin/echo $ONE $TWO ${TWO}</programlisting>
+                                <para>This will execute
+                                <command>/bin/echo</command> with four
+                                arguments: <literal>one</literal>,
+                                <literal>two</literal>,
+                                <literal>two</literal>, and
+                                <literal>two two</literal>.</para>
+                              </listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 that multiple command lines are allowed
                                 and the commands are executed one
                                 after the other, serially.</para>
+
+                                <para>If any of those commands (not
+                                prefixed with <literal>-</literal>)
+                                fail, the rest are not executed and
+                                the unit is considered failed.</para>
                                 </listitem>
                         </varlistentry>
 
                                 optional. Specifier and environment
                                 variable substitution is supported
                                 here following the same scheme as for
-                                <varname>ExecStart=</varname>. One
-                                additional special environment
-                                variables is set: if known
-                                <literal>$MAINPID</literal> is set to
+                                <varname>ExecStart=</varname>.</para>
+
+                                <para>One additional, special
+                                environment variable is set: if known,
+                                <varname>$MAINPID</varname> is set to
                                 the main process of the daemon, and
                                 may be used for command lines like the
-                                following: <command>/bin/kill -HUP
-                                $MAINPID</command>.</para></listitem>
+                                following:</para>
+
+                                <programlisting>/bin/kill -HUP $MAINPID</programlisting>
+                                </listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 following the same scheme as described
                                 for <varname>ExecStart=</varname>
                                 above. Use of this setting is
-                                optional. All processes remaining for
-                                a service after the commands
-                                configured in this option are run are
+                                optional. After the commands configured
+                                in this option are run, all processes
+                                remaining for a service are
                                 terminated according to the
                                 <varname>KillMode=</varname> setting
                                 (see
                                 <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>). If
-                                this option is not specified the
-                                process is terminated right-away when
+                                this option is not specified, the
+                                process is terminated immediately when
                                 service stop is requested. Specifier
                                 and environment variable substitution
                                 is supported (including
-                                <literal>$MAINPID</literal>, see
+                                <varname>$MAINPID</varname>, see
                                 above).</para></listitem>
                         </varlistentry>
 
                                 <term><varname>ExecStopPost=</varname></term>
                                 <listitem><para>Additional commands
                                 that are executed after the service
-                                was stopped using the commands
-                                configured in
-                                <varname>ExecStop=</varname>. This
+                                was stopped. This includes cases where
+                                the commands configured in
+                                <varname>ExecStop=</varname> were used,
+                                where the service does not have any
+                                <varname>ExecStop=</varname> defined, or
+                                where the service exited unexpectedly. This
                                 argument takes multiple command lines,
                                 following the same scheme as described
                                 for <varname>ExecStart</varname>. Use
                                 daemon service does not signal
                                 start-up completion within the
                                 configured time, the service will be
-                                considered failed and be shut down
-                                again.
+                                considered failed and will be shut
+                                down again.
                                 Takes a unit-less value in seconds, or a
                                 time span value such as "5min
-                                20s". Pass 0 to disable the timeout
-                                logic. Defaults to 90s, except when
-                                <varname>Type=oneshot</varname> is
-                                used in which case the timeout
+                                20s". Pass <literal>0</literal> to
+                                disable the timeout logic. Defaults to
+                                <varname>TimeoutStartSec=</varname> from
+                                the manager configuration file, except
+                                when <varname>Type=oneshot</varname> is
+                                used, in which case the timeout
                                 is disabled by default.
                                 </para></listitem>
                         </varlistentry>
                                 <term><varname>TimeoutStopSec=</varname></term>
                                 <listitem><para>Configures the time to
                                 wait for stop. If a service is asked
-                                to stop but does not terminate in the
+                                to stop, but does not terminate in the
                                 specified time, it will be terminated
-                                forcibly via SIGTERM, and after
-                                another delay of this time with
-                                SIGKILL (See
+                                forcibly via <constant>SIGTERM</constant>,
+                                and after another timeout of equal duration
+                                with <constant>SIGKILL</constant> (see
                                 <varname>KillMode=</varname>
                                 in <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
                                 Takes a unit-less value in seconds, or a
                                 time span value such as "5min
-                                20s". Pass 0 to disable the timeout
-                                logic. Defaults to 90s.
+                                20s". Pass <literal>0</literal> to disable
+                                the timeout logic. Defaults to
+                                <varname>TimeoutStartSec=</varname> from the
+                                manager configuration file.
                                 </para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 <term><varname>WatchdogSec=</varname></term>
                                 <listitem><para>Configures the
-                                watchdog timeout for a service. This
-                                is activated when the start-up is
+                                watchdog timeout for a service. The
+                                watchdog is activated when the start-up is
                                 completed. The service must call
                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>
-                                regularly with "WATCHDOG=1" (i.e. the
-                                "keep-alive ping"). If the time
+                                regularly with <literal>WATCHDOG=1</literal>
+                                (i.e. the "keep-alive ping"). If the time
                                 between two such calls is larger than
-                                the configured time then the service
-                                is placed in a failure state. By
+                                the configured time, then the service
+                                is placed in a failed state. By
                                 setting <varname>Restart=</varname> to
                                 <option>on-failure</option> or
-                                <option>always</option> the service
+                                <option>always</option>, the service
                                 will be automatically restarted. The
                                 time configured here will be passed to
                                 the executed service process in the
                                 daemons to automatically enable the
                                 keep-alive pinging logic if watchdog
                                 support is enabled for the service. If
-                                this option is used
+                                this option is used,
                                 <varname>NotifyAccess=</varname> (see
                                 below) should be set to open access to
                                 the notification socket provided by
                         <varlistentry>
                                 <term><varname>Restart=</varname></term>
                                 <listitem><para>Configures whether the
-                                main service process shall be
-                                restarted when it exits. Takes one of
+                                service shall be restarted when the
+                                service process exits, is killed,
+                                or a timeout is reached. The service
+                                process may be the main service
+                                process, but it may also be one of the
+                                processes specified with
+                                <varname>ExecStartPre=</varname>,
+                                <varname>ExecStartPost=</varname>,
+                                <varname>ExecStopPre=</varname>,
+                                <varname>ExecStopPost=</varname>, or
+                                <varname>ExecReload=</varname>.
+                                When the death of the process is a
+                                result of systemd operation (e.g. service
+                                stop or restart), the service will not be
+                                restarted. Timeouts include missing
+                                the watchdog "keep-alive ping"
+                                deadline and a service start, reload,
+                                and stop operation timeouts.</para>
+
+                                <para>Takes one of
                                 <option>no</option>,
                                 <option>on-success</option>,
                                 <option>on-failure</option>,
-                                <option>on-abort</option> or
+                                <option>on-watchdog</option>,
+                                <option>on-abort</option>, or
                                 <option>always</option>. If set to
-                                <option>no</option> (the default) the
-                                service will not be restarted when it
-                                exits. If set to
-                                <option>on-success</option> it will be
-                                restarted only when it exited cleanly,
-                                i.e. terminated with an exit code of
-                                0. If set to
-                                <option>on-failure</option> it will be
-                                restarted only when it exited with an
-                                exit code not equaling 0, when
-                                terminated by a signal (including on
+                                <option>no</option> (the default), the
+                                service will not be restarted. If set to
+                                <option>on-success</option>, it will be
+                                restarted only when the service process
+                                exits cleanly.
+                                In this context, a clean exit means
+                                an exit code of 0, or one of the signals
+                                <constant>SIGHUP</constant>,
+                                <constant>SIGINT</constant>,
+                                <constant>SIGTERM</constant>,
+                                or <constant>SIGPIPE</constant>, and
+                                additionally, exit statuses and signals
+                                specified in <varname>SuccessExitStatus=</varname>.
+                                If set to <option>on-failure</option>,
+                                the service will be restarted when the
+                                process exits with a non-zero exit code,
+                                is terminated by a signal (including on
                                 core dump), when an operation (such as
-                                service reload) times out or when the
-                                configured watchdog timeout is
-                                triggered. If set to
-                                <option>on-abort</option> it will be
-                                restarted only if it exits due to
-                                reception of an uncaught signal
-                                (including on core dump). If set to
-                                <option>always</option> the service
-                                will be restarted regardless whether
+                                service reload) times out, and when the
+                                configured watchdog timeout is triggered.
+                                If set to
+                                <option>on-abort</option>, the service
+                                will be restarted only if the service
+                                process exits due to an uncaught
+                                signal not specified as a clean exit
+                                status.
+                                If set to
+                                <option>on-watchdog</option>, the service
+                                will be restarted only if the watchdog
+                                timeout for the service expires.
+                                If set to
+                                <option>always</option>, the service
+                                will be restarted regardless of whether
                                 it exited cleanly or not, got
-                                terminated abnormally by a signal or
-                                hit a timeout.</para></listitem>
+                                terminated abnormally by a signal, or
+                                hit a timeout.</para>
+
+                                <para>In addition to the above settings,
+                                the service will not be restarted if the
+                                exit code or signal is specified in
+                                <varname>RestartPreventExitStatus=</varname>
+                                (see below).</para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 by the main service process will be
                                 considered successful termination, in
                                 addition to the normal successful exit
-                                code 0 and the signals SIGHUP, SIGINT,
-                                SIGTERM and SIGPIPE. Exit status
+                                code 0 and the signals <constant>SIGHUP</constant>, <constant>SIGINT</constant>,
+                                <constant>SIGTERM</constant>, and <constant>SIGPIPE</constant>. Exit status
                                 definitions can either be numeric exit
-                                codes or termination signal names, and
-                                are separated by spaces. Example:
-                                "<literal>SuccessExitStatus=1 2 8
-                                SIGKILL</literal>", ensures that exit
-                                codes 1, 2, 8 and the termination
-                                signal SIGKILL are considered clean
-                                service
-                                terminations.</para></listitem>
+                                codes or termination signal names,
+                                separated by spaces. For example:
+                                <programlisting>SuccessExitStatus=1 2 8 <constant>SIGKILL</constant></programlisting>
+                                ensures that exit codes 1, 2, 8 and
+                                the termination signal
+                                <constant>SIGKILL</constant> are
+                                considered clean service terminations.
+                                </para>
+
+                                <para>Note that if a process has a
+                                signal handler installed and exits by
+                                calling
+                                <citerefentry><refentrytitle>_exit</refentrytitle><manvolnum>2</manvolnum></citerefentry>
+                                in response to a signal, the
+                                information about the signal is lost.
+                                Programs should instead perform cleanup and kill themselves with the same signal instead. See
+                                <ulink url="http://www.cons.org/cracauer/sigint.html">Proper handling of SIGINT/SIGQUIT — How to be a proper program</ulink>.</para>
+
+                                <para>This option may appear more than once,
+                                in which case the list of successful
+                                exit statuses is merged. If the empty
+                                string is assigned to this option, the
+                                list is reset, all prior assignments
+                                of this option will have no
+                                effect.</para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 <listitem><para>Takes a list of exit
                                 status definitions that when returned
                                 by the main service process will
-                                prevent automatic service restarts
+                                prevent automatic service restarts,
                                 regardless of the restart setting
                                 configured with
                                 <varname>Restart=</varname>. Exit
                                 numeric exit codes or termination
                                 signal names, and are separated by
                                 spaces. Defaults to the empty list, so
-                                that by default no exit status is
+                                that, by default, no exit status is
                                 excluded from the configured restart
                                 logic. Example:
-                                "<literal>RestartPreventExitStatus=1 6
-                                SIGABRT</literal>", ensures that exit
-                                codes 1 and 6 and the termination signal
-                                SIGABRT will not result in automatic
-                                service restarting.</para></listitem>
+                                <literal>RestartPreventExitStatus=1 6
+                                SIGABRT</literal>, ensures that exit
+                                codes 1 and 6 and the termination
+                                signal <constant>SIGABRT</constant> will
+                                not result in automatic service
+                                restarting. This
+                                option may appear more than once, in
+                                which case the list of restart-preventing
+                                statuses is merged. If the empty
+                                string is assigned to this option, the
+                                list is reset and all prior assignments
+                                of this option will have no
+                                effect.</para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 <term><varname>PermissionsStartOnly=</varname></term>
                                 <listitem><para>Takes a boolean
-                                argument. If true, the permission
-                                related execution options as
+                                argument. If true, the permission-related
+                                execution options, as
                                 configured with
                                 <varname>User=</varname> and similar
                                 options (see
                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
-                                for more information) are only applied
+                                for more information), are only applied
                                 to the process started with
                                 <varname>ExecStart=</varname>, and not
                                 to the various other
                                 <varname>ExecStartPre=</varname>,
                                 <varname>ExecStartPost=</varname>,
                                 <varname>ExecReload=</varname>,
-                                <varname>ExecStop=</varname>,
+                                <varname>ExecStop=</varname>, and
                                 <varname>ExecStopPost=</varname>
                                 commands. If false, the setting is
                                 applied to all configured commands the
                         <varlistentry>
                                 <term><varname>RootDirectoryStartOnly=</varname></term>
                                 <listitem><para>Takes a boolean
-                                argument. If true, the root directory
+                                argument. If true, the root directory,
                                 as configured with the
                                 <varname>RootDirectory=</varname>
                                 option (see
                                 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
-                                for more information) is only applied
+                                for more information), is only applied
                                 to the process started with
                                 <varname>ExecStart=</varname>, and not
                                 to the various other
                                 <varname>ExecStartPre=</varname>,
                                 <varname>ExecStartPost=</varname>,
                                 <varname>ExecReload=</varname>,
-                                <varname>ExecStop=</varname>,
+                                <varname>ExecStop=</varname>, and
                                 <varname>ExecStopPost=</varname>
                                 commands. If false, the setting is
                                 applied to all configured commands the
 
                         <varlistentry>
                                 <term><varname>NonBlocking=</varname></term>
-                                <listitem><para>Set O_NONBLOCK flag
+                                <listitem><para>Set the
+                                <constant>O_NONBLOCK</constant> flag
                                 for all file descriptors passed via
                                 socket-based activation. If true, all
                                 file descriptors >= 3 (i.e. all except
-                                STDIN/STDOUT/STDERR) will have
-                                the O_NONBLOCK flag set and hence are in
+                                stdin, stdout, and stderr) will have
+                                the <constant>O_NONBLOCK</constant> flag
+                                set and hence are in
                                 non-blocking mode. This option is only
                                 useful in conjunction with a socket
                                 unit, as described in
                                 <option>none</option> (the default),
                                 <option>main</option> or
                                 <option>all</option>. If
-                                <option>none</option> no daemon status
+                                <option>none</option>, no daemon status
                                 updates are accepted from the service
                                 processes, all status update messages
-                                are ignored. If <option>main</option>
+                                are ignored. If <option>main</option>,
                                 only service updates sent from the
                                 main process of the service are
-                                accepted. If <option>all</option> all
+                                accepted. If <option>all</option>, all
                                 services updates from all members of
                                 the service's control group are
                                 accepted. This option should be set to
                                 open access to the notification socket
                                 when using
                                 <varname>Type=notify</varname> or
-                                <varname>WatchdogUsec=</varname> (see
+                                <varname>WatchdogSec=</varname> (see
                                 above). If those options are used but
-                                <varname>NotifyAccess=</varname> not
-                                configured it will be implicitly set
+                                <varname>NotifyAccess=</varname> is not
+                                configured, it will be implicitly set
                                 to
                                 <option>main</option>.</para></listitem>
                         </varlistentry>
                                 passed to multiple processes at the
                                 same time. Also note that a different
                                 service may be activated on incoming
-                                traffic than inherits the sockets. Or
-                                in other words: The
+                                traffic than that which inherits the
+                                sockets. Or in other words: the
                                 <varname>Service=</varname> setting of
                                 <filename>.socket</filename> units
-                                doesn't have to match the inverse of the
-                                <varname>Sockets=</varname> setting of
-                                the <filename>.service</filename> it
-                                refers to.</para></listitem>
+                                does not have to match the inverse of
+                                the <varname>Sockets=</varname>
+                                setting of the
+                                <filename>.service</filename> it
+                                refers to.</para>
+
+                                <para>This option may appear more than
+                                once, in which case the list of socket
+                                units is merged. If the empty string
+                                is assigned to this option, the list of
+                                sockets is reset, and all prior uses of
+                                this setting will have no
+                                effect.</para></listitem>
                         </varlistentry>
 
                         <varlistentry>
                                 <term><varname>StartLimitBurst=</varname></term>
 
                                 <listitem><para>Configure service
-                                start rate limiting. By default
-                                services which are started more often
-                                than 5 times within 10s are not
+                                start rate limiting. By default,
+                                services which are started more
+                                than 5 times within 10 seconds are not
                                 permitted to start any more times
-                                until the 10s interval ends. With
-                                these two options this rate limiting
+                                until the 10 second interval ends. With
+                                these two options, this rate limiting
                                 may be modified. Use
                                 <varname>StartLimitInterval=</varname>
-                                to configure the checking interval
-                                (defaults to 10s, set to 0 to disable
+                                to configure the checking interval (defaults to
+                                <varname>DefaultStartLimitInterval=</varname> in
+                                manager configuration file, set to 0 to disable
                                 any kind of rate limiting). Use
                                 <varname>StartLimitBurst=</varname> to
                                 configure how many starts per interval
-                                are allowed (defaults to 5). These
+                                are allowed (defaults to
+                                <varname>DefaultStartLimitBurst=</varname> in
+                                manager configuration file). These
                                 configuration options are particularly
                                 useful in conjunction with
-                                <varname>Restart=</varname>, however
-                                apply to all kinds of starts
+                                <varname>Restart=</varname>; however,
+                                they apply to all kinds of starts
                                 (including manual), not just those
                                 triggered by the
                                 <varname>Restart=</varname> logic.
                                 Note that units which are configured
                                 for <varname>Restart=</varname> and
                                 which reach the start limit are not
-                                attempted to be restarted anymore,
-                                however they may still be restarted
-                                manually at a later point from which
-                                point on the restart logic is again
+                                attempted to be restarted anymore;
+                                however, they may still be restarted
+                                manually at a later point, from which
+                                point on, the restart logic is again
                                 activated. Note that
                                 <command>systemctl
                                 reset-failed</command> will cause the
                                 hit. Takes one of
                                 <option>none</option>,
                                 <option>reboot</option>,
-                                <option>reboot-force</option> or
+                                <option>reboot-force</option>, or
                                 <option>reboot-immediate</option>. If
                                 <option>none</option> is set,
                                 hitting the rate limit will trigger no
                                 action besides that the start will not
-                                be
-                                permitted. <option>reboot</option>
+                                be permitted. <option>reboot</option>
                                 causes a reboot following the normal
                                 shutdown procedure (i.e. equivalent to
-                                <command>systemctl reboot</command>),
+                                <command>systemctl reboot</command>).
                                 <option>reboot-force</option> causes
-                                an forced reboot which will terminate
+                                a forced reboot which will terminate
                                 all processes forcibly but should
                                 cause no dirty file systems on reboot
                                 (i.e. equivalent to <command>systemctl
                                 causes immediate execution of the
                                 <citerefentry><refentrytitle>reboot</refentrytitle><manvolnum>2</manvolnum></citerefentry>
                                 system call, which might result in
-                                data loss.  Defaults to
+                                data loss. Defaults to
                                 <option>none</option>.</para></listitem>
                         </varlistentry>
 
                 for compatibility reasons and should not be used in
                 newly written service files.</para>
 
-                <variablelist>
+                <variablelist class='unit-directives'>
                         <varlistentry>
                                 <term><varname>SysVStartPriority=</varname></term>
                                 <listitem><para>Set the SysV start
                                 in relation to SysV services lacking
                                 LSB headers. This option is only
                                 necessary to fix ordering in relation
-                                to legacy SysV services, that have no
+                                to legacy SysV services that have no
                                 ordering information encoded in the
-                                script headers. As such it should only
-                                be used as temporary compatibility
-                                option, and not be used in new unit
-                                files. Almost always it is a better
+                                script headers. As such, it should only
+                                be used as temporary compatibility
+                                option and should not be used in new unit
+                                files. Almost always, it is a better
                                 choice to add explicit ordering
                                 directives via
                                 <varname>After=</varname> or
                                 <varname>Before=</varname>,
-                                instead. For more details see
-                                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
-                                used, pass an integer value in the
+                                instead. For more details, see
+                                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+                                If used, pass an integer value in the
                                 range 0-99.</para></listitem>
                         </varlistentry>
-
-                        <varlistentry>
-                                <term><varname>FsckPassNo=</varname></term>
-                                <listitem><para>Set the fsck passno
-                                priority to use to order this service
-                                in relation to other file system
-                                checking services. This option is only
-                                necessary to fix ordering in relation
-                                to fsck jobs automatically created for
-                                all <filename>/etc/fstab</filename>
-                                entries with a value in the fs_passno
-                                column > 0. As such it should only be
-                                used as option for fsck
-                                services. Almost always it is a better
-                                choice to add explicit ordering
-                                directives via
-                                <varname>After=</varname> or
-                                <varname>Before=</varname>,
-                                instead. For more details see
-                                <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. If
-                                used, pass an integer value in the
-                                same range as
-                                <filename>/etc/fstab</filename>'s
-                                fs_passno column. See
-                                <citerefentry><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>
-                                for details.</para></listitem>
-                        </varlistentry>
-
                 </variablelist>
         </refsect1>
 
                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-                          <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+                          <citerefentry><refentrytitle>systemd.resource-control</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemd.kill</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>systemd.directives</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                   </para>
         </refsect1>