man: fix incorrectly placed full stop

[thirdparty/systemd.git] / man / systemd-notify.xml

diff --git a/man/systemd-notify.xml b/man/systemd-notify.xml
index 11584731178ed134336735e2a96c030443879972..6d583003baca6c1e531da3e91011f17ac0b446f7 100644 (file)
--- a/man/systemd-notify.xml
+++ b/man/systemd-notify.xml
@@ -1,28 +1,7 @@
 <?xml version='1.0'?> <!--*-nxml-*-->
 <?xml version='1.0'?> <!--*-nxml-*-->

-<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
-  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
-<!ENTITY % entities SYSTEM "custom-entities.ent" >
-%entities;
-]>
-
-<!--
-  This file is part of systemd.
-
-  Copyright 2010 Lennart Poettering
-
-  systemd is free software; you can redistribute it and/or modify it
-  under the terms of the GNU Lesser General Public License as published by
-  the Free Software Foundation; either version 2.1 of the License, or
-  (at your option) any later version.
-
-  systemd is distributed in the hope that it will be useful, but
-  WITHOUT ANY WARRANTY; without even the implied warranty of
-  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-  Lesser General Public License for more details.
-
-  You should have received a copy of the GNU Lesser General Public License
-  along with systemd; If not, see <http://www.gnu.org/licenses/>.
--->
+<!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+ -->

 
 <refentry id="systemd-notify"
     xmlns:xi="http://www.w3.org/2001/XInclude">
 
 <refentry id="systemd-notify"
     xmlns:xi="http://www.w3.org/2001/XInclude">


@@ -30,15 +9,6 @@
   <refentryinfo>
     <title>systemd-notify</title>
     <productname>systemd</productname>
   <refentryinfo>
     <title>systemd-notify</title>
     <productname>systemd</productname>

-
-    <authorgroup>
-      <author>
-        <contrib>Developer</contrib>
-        <firstname>Lennart</firstname>
-        <surname>Poettering</surname>
-        <email>lennart@poettering.net</email>
-      </author>
-    </authorgroup>

   </refentryinfo>
 
   <refmeta>
   </refentryinfo>
 
   <refmeta>


@@ -63,7 +33,7 @@
     <para><command>systemd-notify</command> may be called by daemon
     scripts to notify the init system about status changes. It can be
     used to send arbitrary information, encoded in an
     <para><command>systemd-notify</command> may be called by daemon
     scripts to notify the init system about status changes. It can be
     used to send arbitrary information, encoded in an

-    environment-block-like list of strings. Most importantly it can be
+    environment-block-like list of strings. Most importantly, it can be

     used for start-up completion notification.</para>
 
     <para>This is mostly just a wrapper around
     used for start-up completion notification.</para>
 
     <para>This is mostly just a wrapper around


@@ -75,9 +45,27 @@
     <para>The command line may carry a list of environment variables
     to send as part of the status update.</para>
 
     <para>The command line may carry a list of environment variables
     to send as part of the status update.</para>
 

-    <para>Note that systemd will refuse reception of status updates
-    from this command unless <varname>NotifyAccess=all</varname> is
-    set for the service unit this command is called from.</para>
+    <para>Note that systemd will refuse reception of status updates from this command unless
+    <varname>NotifyAccess=</varname> is set for the service unit this command is called from.</para>
+
+    <para>Note that <function>sd_notify()</function> notifications may be attributed to units correctly only if either
+    the sending process is still around at the time PID 1 processes the message, or if the sending process is
+    explicitly runtime-tracked by the service manager. The latter is the case if the service manager originally forked
+    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. 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>
 


@@ -100,22 +88,32 @@
       <varlistentry>
         <term><option>--pid=</option></term>
 
       <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>
 
         <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
       </varlistentry>
 

+      <varlistentry>
+        <term><option>--uid=</option><replaceable>USER</replaceable></term>
+
+        <listitem><para>Set the user ID to send the notification from. Takes a UNIX user name or numeric UID. When
+        specified the notification message will be sent with the specified UID as sender, in place of the user the
+        command was invoked as. This option requires sufficient privileges in order to be able manipulate the user
+        identity of the process.</para></listitem>
+      </varlistentry>
+

       <varlistentry>
         <term><option>--status=</option></term>
 
         <listitem><para>Send a free-form status string for the daemon
         to the init systemd. This option takes the status string as
         argument. This is equivalent to <command>systemd-notify
       <varlistentry>
         <term><option>--status=</option></term>
 
         <listitem><para>Send a free-form status string for the daemon
         to the init systemd. This option takes the status string as
         argument. This is equivalent to <command>systemd-notify

-        STATUS=...</command>. For details about the semantics of this
+        STATUS=…</command>. For details about the semantics of this

         option see
         <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
       </varlistentry>
         option see
         <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
       </varlistentry>


@@ -127,7 +125,23 @@
         systemd, non-zero otherwise. If this option is passed, no
         message is sent. This option is hence unrelated to the other
         options. For details about the semantics of this option, see
         systemd, non-zero otherwise. If this option is passed, no
         message is sent. This option is hence unrelated to the other
         options. For details about the semantics of this option, see

-        <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
+        <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>. An
+        alternate way to check for this state is to call
+        <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+        with the <command>is-system-running</command> command. It will
+        return <literal>offline</literal> if the system was not booted
+        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" />
       </varlistentry>
 
       <xi:include href="standard-options.xml" xpointer="help" />


@@ -156,15 +170,15 @@
       <programlisting>#!/bin/bash
 
 mkfifo /tmp/waldo
       <programlisting>#!/bin/bash
 
 mkfifo /tmp/waldo

-systemd-notify --ready --status="Waiting for data..."
+systemd-notify --ready --status="Waiting for data…"

 
 while : ; do
 
 while : ; do

-  read a &lt; /tmp/waldo
-  systemd-notify --status="Processing $a"
+        read a &lt; /tmp/waldo
+        systemd-notify --status="Processing $a"

 
 

-  # Do something with $a ...
+        # Do something with $a …

 
 

-  systemd-notify --status="Waiting for data..."
+        systemd-notify --status="Waiting for data…"

 done</programlisting>
     </example>
   </refsect1>
 done</programlisting>
     </example>
   </refsect1>