as. This option is mandatory for
services where
<varname>Type=</varname> is set to
- <option>dbus</option>, but its use
- is otherwise recommended if the process
- takes a name on the D-Bus bus.</para>
+ <option>dbus</option>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><varname>BusPolicy=</varname></term>
- <listitem><para>If specfied, a custom kdbus
+ <listitem><para>If specified, a custom
+ <ulink url="https://code.google.com/p/d-bus/">kdbus</ulink>
endpoint will be created and installed as the
default bus node for the service. Such a custom
endpoint can hold an own set of policy rules
of two parts; the bus name, and a verb to
specify to granted access, which is one of
<option>see</option>,
- <option>talk</option> or
+ <option>talk</option>, or
<option>own</option>.
<option>talk</option> implies
<option>see</option>, and <option>own</option>
<term><varname>ExecStart=</varname></term>
<listitem><para>Commands with their
arguments that are executed when this
- service is started. For each of the
- specified commands, the first argument
- must be an absolute and literal path
- to an executable.</para>
+ service is started. The value is split
+ into zero or more command lines is
+ according to the rules described below
+ (see section "Command Lines" below).
+ </para>
<para>When <varname>Type</varname> is
not <option>oneshot</option>, only one
command may and must be given. When
<varname>Type=oneshot</varname> is
- used, none or more than one command
- may be specified. Multiple command
- lines may 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. 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. If no
+ used, zero or more commands may be
+ specified. This can be specified by
+ providing multiple command lines in
+ the same directive, or alternatively,
+ this directive may be specified more
+ than once with the same effect. 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. If no
<varname>ExecStart=</varname> is
specified, then the service must have
<varname>RemainAfterExit=yes</varname>
set.</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><</literal>,
- <literal><<</literal>,
- <literal>></literal>, and
- <literal>>></literal>, pipes
- using <literal>|</literal>, and
- running programs in the background
- using <literal>&</literal>
- and <emphasis>other elements of shell
- syntax are not supported</emphasis>.
- </para>
+ <para>For each of the specified
+ commands, the first argument must be
+ an absolute path to an executable.
+ Optionally, if this file name is
+ prefixed with <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 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
+ can appear in either order.</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>
+ with <literal>-</literal>), other
+ lines are not executed, and the unit
+ is considered failed.</para>
<para>Unless
<varname>Type=forking</varname> is
command line will be considered the
main process of the daemon.</para>
- <para>The command line accepts
- <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>
-
- <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
- will be passed as
- <literal>argv[0]</literal> to the
- executed process, followed by the
- further arguments specified. If the
- 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
- can appear in either order.</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
- explicitly to a shell implementation
- 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 / >/dev/null & \; \
-/bin/ls</programlisting>
- <para>This will execute
- <command>/bin/echo</command> with five
- arguments: <literal>/</literal>,
- <literal>>/dev/null</literal>,
- <literal>&</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>
when <varname>Type=oneshot</varname> is
used, in which case the timeout
is disabled by default
- (see <citerefentry><refentrytitle>systemd-systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
+ (see <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
</para></listitem>
</varlistentry>
the timeout logic. Defaults to
<varname>DefaultTimeoutStopSec=</varname> from the
manager configuration file
- (see <citerefentry><refentrytitle>systemd-systemd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
+ (see <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>).
</para></listitem>
</varlistentry>
(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 failed state. By
- setting <varname>Restart=</varname> to
+ is placed in a failed state and it will
+ be terminated with <varname>SIGABRT</varname>.
+ By setting <varname>Restart=</varname> to
<option>on-failure</option> or
<option>always</option>, the service
will be automatically restarted. The
<term><varname>Sockets=</varname></term>
<listitem><para>Specifies the name of
the socket units this service shall
- inherit the sockets from when the
- service is started. Normally it
- should not be necessary to use this
- setting as all sockets whose unit
+ inherit socket file descriptors
+ from when the service is
+ started. Normally it should not be
+ necessary to use this setting as all
+ socket file descriptors whose unit
shares the same name as the service
- (ignoring the different suffix of course)
- are passed to the spawned
- process.</para>
-
- <para>Note that the same socket may be
- passed to multiple processes at the
- same time. Also note that a different
- service may be activated on incoming
- traffic than that which inherits the
- sockets. Or in other words: the
+ (subject to the different unit name
+ suffix of course) are passed to the
+ spawned process.</para>
+
+ <para>Note that the same socket file
+ descriptors may be passed to multiple
+ processes simultaneously. Also note
+ that a different service may be
+ activated on incoming socket traffic
+ than the one which is ultimately
+ configured to inherit the socket file
+ descriptors. Or in other words: the
<varname>Service=</varname> setting of
<filename>.socket</filename> units
does not have to match the inverse of
command.</para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><varname>FileDescriptorStoreMax=</varname></term>
+ <listitem><para>Configure how many
+ file descriptors may be stored in the
+ service manager for the service using
+ <citerefentry><refentrytitle>sd_pid_notify_with_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>'s
+ <literal>FDSTORE=1</literal>
+ messages. This is useful for
+ implementing service restart schemes
+ where the state is serialized to
+ <filename>/run</filename> and the file
+ descriptors passed to the service
+ manager, to allow restarts without
+ losing state. Defaults to 0, i.e. no
+ file descriptors may be stored in the
+ service manager by default. All file
+ descriptors passed to the service
+ manager from a specific service are
+ passed back to the service's main
+ process on the next service
+ restart. Any file descriptors passed
+ to the service manager are
+ automatically closed when POLLHUP or
+ POLLERR is seen on them, or when the
+ service is fully stopped and no job
+ queued or being executed for
+ it.</para></listitem>
+ </varlistentry>
+
</variablelist>
<para>Check
</refsect1>
<refsect1>
- <title>Compatibility Options</title>
+ <title>Command lines</title>
+
+ <para>This section describes command line parsing and
+ variable and specifier substitions for
+ <varname>ExecStart=</varname>,
+ <varname>ExecStartPre=</varname>,
+ <varname>ExecStartPost=</varname>,
+ <varname>ExecReload=</varname>,
+ <varname>ExecStop=</varname>, and
+ <varname>ExecStopPost=</varname> options.</para>
+
+ <para>Multiple command lines may be concatenated in a
+ single directive by separating them with semicolons
+ (these semicolons must be passed as separate words).
+ Lone semicolons may be escaped as
+ <literal>\;</literal>.</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. C-style escapes are
+ also supported, see table below. Quotes themselves are
+ removed after parsing and escape sequences
+ substituted. In addition, a trailing backslash
+ (<literal>\</literal>) may be used to merge lines.
+ </para>
- <para>The following options are also available in the
- <literal>[Service]</literal> section, but exist purely
- for compatibility reasons and should not be used in
- newly written service files.</para>
+ <para>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><</literal>, <literal><<</literal>,
+ <literal>></literal>, and
+ <literal>>></literal>, pipes using
+ <literal>|</literal>, running programs in the
+ background using <literal>&</literal>, and
+ <emphasis>other elements of shell syntax are not
+ supported</emphasis>.</para>
+
+ <para>The command to execute must an absolute path
+ name. It may contain spaces, but control characters
+ are not allowed.</para>
+
+ <para>The command line accepts <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>
+
+ <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. For this type of
+ expansion, quotes and respected when splitting into
+ words, and afterwards removed.</para>
+
+ <para>Example:</para>
+
+ <programlisting>Environment="ONE=one" 'TWO=two two'
+ExecStart=/bin/echo $ONE $TWO ${TWO}</programlisting>
- <variablelist class='unit-directives'>
- <varlistentry>
- <term><varname>SysVStartPriority=</varname></term>
- <listitem><para>Set the SysV start
- priority to use to order this service
- 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
- ordering information encoded in the
- script headers. As such, it should only
- be used as a 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
- range 0-99.</para></listitem>
- </varlistentry>
- </variablelist>
+ <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>
+
+ <para>Example:</para>
+ <programlisting>Environment=ONE='one' "TWO='two two' too" THREE=
+ExecStart=/bin/echo ${ONE} ${TWO} ${THREE}
+ExecStart=/bin/echo $ONE $TWO $THREE</programlisting>
+ <para>This results in <filename>echo</filename> being
+ called twice, the first time with arguments
+ <literal>'one'</literal>,
+ <literal>'two two' too</literal>, <literal></literal>,
+ and the second time with arguments
+ <literal>one</literal>, <literal>two two</literal>,
+ <literal>too</literal>.
+ </para>
+
+ <para>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>Note that shell command lines are not directly
+ supported. If shell command lines are to be used, they
+ need to be passed explicitly to a shell implementation
+ 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 / >/dev/null & \; \
+/bin/ls</programlisting>
+
+ <para>This will execute <command>/bin/echo</command>
+ with five arguments: <literal>/</literal>,
+ <literal>>/dev/null</literal>,
+ <literal>&</literal>, <literal>;</literal>, and
+ <literal>/bin/ls</literal>.</para>
+
+ <table>
+ <title>C escapes supported in command lines and environment variables</title>
+ <tgroup cols='2'>
+ <colspec colname='escape' />
+ <colspec colname='meaning' />
+ <thead>
+ <row>
+ <entry>Literal</entry>
+ <entry>Actual value</entry>
+ </row>
+ </thead>
+ <tbody>
+ <row>
+ <entry><literal>\a</literal></entry>
+ <entry>bell</entry>
+ </row>
+ <row>
+ <entry><literal>\b</literal></entry>
+ <entry>backspace</entry>
+ </row>
+ <row>
+ <entry><literal>\f</literal></entry>
+ <entry>form feed</entry>
+ </row>
+ <row>
+ <entry><literal>\n</literal></entry>
+ <entry>newline</entry>
+ </row>
+ <row>
+ <entry><literal>\r</literal></entry>
+ <entry>carriage return</entry>
+ </row>
+ <row>
+ <entry><literal>\t</literal></entry>
+ <entry>tab</entry>
+ </row>
+ <row>
+ <entry><literal>\v</literal></entry>
+ <entry>vertical tab</entry>
+ </row>
+ <row>
+ <entry><literal>\\</literal></entry>
+ <entry>backslash</entry>
+ </row>
+ <row>
+ <entry><literal>\"</literal></entry>
+ <entry>double quotation mark</entry>
+ </row>
+ <row>
+ <entry><literal>\'</literal></entry>
+ <entry>single quotation mark</entry>
+ </row>
+ <row>
+ <entry><literal>\s</literal></entry>
+ <entry>space</entry>
+ </row>
+ <row>
+ <entry><literal>\x<replaceable>xx</replaceable></literal></entry>
+ <entry>character number <replaceable>xx</replaceable> in hexadecimal encoding</entry>
+ </row>
+ <row>
+ <entry><literal>\<replaceable>nnn</replaceable></literal></entry>
+ <entry>character number <replaceable>nnn</replaceable> in octal encoding</entry>
+ </row>
+ </tbody>
+ </tgroup>
+ </table>
</refsect1>
<refsect1>
projects / thirdparty / systemd.git / blobdiff