<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
replaced by the value of the
environment variable including all
whitespace it contains, resulting in a
- single argument. Use
+ 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 zero or
- more arguments. To pass a literal dollar sign,
- use <literal>$$</literal>. Note that the first
- argument (i.e. the program to execute)
- may not be a variable.</para>
+ of the environment variable split at
+ whitespace, resulting in zero or more
+ arguments. To pass a literal dollar
+ sign, use <literal>$$</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
+ section "Environment variables in
+ spawned processes" in
+ <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ which are considered "static
+ configuration" may used (this includes
+ e.g. <varname>$USER</varname>, but not
+ <varname>$TERM</varname>).</para>
<para>Optionally, if the absolute file
name is prefixed with
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>Only select environment variables
- are set for executed commands. See
- <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
- </para>
-
+ <programlisting>ExecStart=/bin/sh -c 'dmesg | tac'</programlisting>
<para>Example:</para>
- <programlisting>ExecStart=/bin/echo one ; /bin/echo "two two"
- </programlisting>
+ <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. Since two commands are
- specified
+ specified,
<varname>Type=oneshot</varname> must
be used.</para>
<para>Example:</para>
<programlisting>ExecStart=/bin/echo / >/dev/null & \; \
-/bin/ls
- </programlisting>
+/bin/ls</programlisting>
<para>This will execute
<command>/bin/echo</command> with five
arguments: <literal>/</literal>,
<para>Example:</para>
<programlisting>Environment="ONE=one" 'TWO=two two'
-ExecStart=/bin/echo $ONE $TWO ${TWO}
- </programlisting>
+ExecStart=/bin/echo $ONE $TWO ${TWO}</programlisting>
<para>This will execute
<command>/bin/echo</command> with four
arguments: <literal>one</literal>,
timeout for the service expires.
If set to
<option>always</option>, the service
- will be restarted regardless whether
+ will be restarted regardless of whether
it exited cleanly or not, got
terminated abnormally by a signal or
hit a timeout.</para>
considered successful termination, in
addition to the normal successful exit
code 0 and the signals <constant>SIGHUP</constant>, <constant>SIGINT</constant>,
- <constant>SIGTERM</constant> and <constant>SIGPIPE</constant>. Exit status
+ <constant>SIGTERM</constant>, and <constant>SIGPIPE</constant>. Exit status
definitions can either be numeric exit
codes or termination signal names,
- separated by spaces. Example:
- <literal>SuccessExitStatus=1 2 8
- <constant>SIGKILL</constant></literal>, ensures that exit
- codes 1, 2, 8 and the termination
- signal <constant>SIGKILL</constant> are considered clean
- service terminations. 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>
+ separated by spaces. Signals will only
+ be considered if the service does not implement
+ a signal handler and exits as a direct result
+ of receiving the signal. 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>
~ianmdlvl / elogind.git / blobdiff