configured with
<varname>ExecStart=</varname> is the
main process of the service. In this
- mode, communication channels must be
- installed before the daemon is started
- up (e.g. sockets set up by systemd,
- via socket activation), as systemd
- will immediately proceed starting
- follow-up units.</para>
+ mode, if the process offers
+ functionality to other processes on
+ 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
+ systemd will immediately proceed
+ starting follow-up units.</para>
<para>If set to
<option>forking</option> it is
expected that the process configured
with <varname>ExecStart=</varname>
- will start up and call
- <function>fork()</function>. The
- parent process is expected to finish
- when start-up is complete and all
- communication channels set up. The
- child continues to run as the main
- daemon process. This is the behaviour
- of traditional UNIX daemons. If this
+ 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
+ to run as the main daemon
+ process. This is the behaviour of
+ traditional UNIX daemons. If this
setting is used, it is recommended to
also use the
<varname>PIDFile=</varname> option, so
will proceed starting follow-up units
after the D-Bus bus name has been
acquired. Service units with this
- option configured implicitly have
+ option configured implicitly gain
dependencies on the
<filename>dbus.target</filename>
unit.</para>
notification message has been sent. If
this option is used
<varname>NotifyAccess=</varname> (see
- below) must be set to open access to
+ 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
+ set, it will implicitly be set to
<option>main</option>.</para>
</listitem>
</varlistentry>
arguments for the process. It is
mandatory to set this option for all
services. This option may not be
- specified more than once. Optionally,
- if the absolute file name is prefixed
- with <literal>@</literal>, the second
- token will be passed as
+ specified more than once, except when
+ <varname>Type=oneshot</varname> is
+ used in which case more than one
+ <varname>ExecStart=</varname> line is
+ accepted which are then invoked one by
+ one, sequentially in the order they
+ appear in the unit file.</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
first token is prefixed with
- <literal>-</literal> an error code of
+ <literal>-</literal> an exit code of
the command normally considered a
- failure is ignored and considered
- success. If both <literal>-</literal>
- and <literal>@</literal> are used for
- the same command the latter must
- preceed the latter. Unless
+ failure (i.e. non-zero exit status or
+ abormal exit due to signal) is ignored
+ and considered success. If both
+ <literal>-</literal> and
+ <literal>@</literal> are used for the
+ same command the former must preceed
+ the latter. Unless
<varname>Type=forking</varname> is
set, the process started via this
command line will be considered the