<?xml version='1.0'?> <!--*-nxml-*-->
-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
-
-<!--
- SPDX-License-Identifier: LGPL-2.1+
--->
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
<refentry id="systemd-notify"
xmlns:xi="http://www.w3.org/2001/XInclude">
off the process, i.e. on all processes that match <varname>NotifyAccess=</varname><option>main</option> or
<varname>NotifyAccess=</varname><option>exec</option>. Conversely, if an auxiliary process of the unit sends an
<function>sd_notify()</function> message and immediately exits, the service manager might not be able to properly
- attribute the message to the unit, and thus will ignore it, even if
- <varname>NotifyAccess=</varname><option>all</option> is set for it.</para>
-
- <para><command>systemd-notify</command> will first attempt to invoke <function>sd_notify()</function> pretending to
- have the PID of the invoking process. This will only succeed when invoked with sufficient privileges. On failure,
- it will then fall back to invoking it under its own PID. This behaviour is useful in order that when the tool is
- invoked from a shell script the shell process — and not the <command>systemd-notify</command> process — appears as
- sender of the message, which in turn is helpful if the shell process is the main process of a service, due to the
- limitations of <varname>NotifyAccess=</varname><option>all</option> described above.</para>
+ attribute the message to the unit, and thus will ignore it, even if <varname>NotifyAccess=</varname><option>all
+ </option> is set for it. When <option>--no-block</option> is used, all synchronization for reception of notifications
+ is disabled, and hence the aforementioned race may occur if the invoking process is not the service manager or spawned
+ by the service manager.</para>
+
+ <para>Hence, <command>systemd-notify</command> will first attempt to invoke <function>sd_notify()</function>
+ pretending to have the PID of the invoking process. This will only succeed when invoked with sufficient privileges.
+ On failure, it will then fall back to invoking it under its own PID. This behaviour is useful in order that when
+ the tool is invoked from a shell script the shell process — and not the <command>systemd-notify</command> process
+ — appears as sender of the message, which in turn is helpful if the shell process is the main process of a service,
+ due to the limitations of <varname>NotifyAccess=</varname><option>all</option>. Use the <option>--pid=</option>
+ switch to tweak this behaviour.</para>
+
</refsect1>
<refsect1>
<varlistentry>
<term><option>--pid=</option></term>
- <listitem><para>Inform the init system about the main PID of
- the daemon. Takes a PID as argument. If the argument is
- omitted, the PID of the process that invoked
- <command>systemd-notify</command> is used. This is equivalent
- to <command>systemd-notify MAINPID=$PID</command>. For details
- about the semantics of this option see
+ <listitem><para>Inform the service manager about the main PID of the daemon. Takes a PID as
+ argument. If the argument is specified as <literal>auto</literal> or omitted, the PID of the process
+ that invoked <command>systemd-notify</command> is used, except if that's the service manager. If the
+ argument is specified as <literal>self</literal>, the PID of the <command>systemd-notify</command>
+ command itself is used, and if <literal>parent</literal> is specified the calling process' PID is
+ used — even if it is the service manager. This is equivalent to <command>systemd-notify
+ MAINPID=$PID</command>. For details about the semantics of this option see
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
</varlistentry>
with systemd. </para></listitem>
</varlistentry>
+ <varlistentry>
+ <term><option>--no-block</option></term>
+
+ <listitem><para>Do not synchronously wait for the requested operation to finish.
+ Use of this option is only recommended when <command>systemd-notify</command>
+ is spawned by the service manager, or when the invoking process is directly spawned
+ by the service manager and has enough privileges to allow <command>systemd-notify
+ </command> to send the notification on its behalf. Sending notifications with
+ this option set is prone to race conditions in all other cases.</para></listitem>
+ </varlistentry>
+
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
</variablelist>