Adding upstream version 252.22.upstream/252.22upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 196 insertions, 0 deletions

diff --git a/man/systemd-notify.xml b/man/systemd-notify.xml
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+<?xml version='1.0'?> <!--*-nxml-*-->
+<!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-or-later -->
+
+<refentry id="systemd-notify"
+    xmlns:xi="http://www.w3.org/2001/XInclude">
+
+  <refentryinfo>
+    <title>systemd-notify</title>
+    <productname>systemd</productname>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>systemd-notify</refentrytitle>
+    <manvolnum>1</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>systemd-notify</refname>
+    <refpurpose>Notify service manager about start-up completion and other daemon status changes</refpurpose>
+  </refnamediv>
+
+  <refsynopsisdiv>
+    <cmdsynopsis>
+      <command>systemd-notify <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">VARIABLE=VALUE</arg></command>
+    </cmdsynopsis>
+  </refsynopsisdiv>
+
+  <refsect1>
+    <title>Description</title>
+
+    <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
+    used for start-up completion notification.</para>
+
+    <para>This is mostly just a wrapper around
+    <function>sd_notify()</function> and makes this functionality
+    available to shell scripts. For details see
+    <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+    </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=</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>
+    <title>Options</title>
+
+    <para>The following options are understood:</para>
+
+    <variablelist>
+      <varlistentry>
+        <term><option>--ready</option></term>
+
+        <listitem><para>Inform the init system about service start-up
+        completion. This is equivalent to <command>systemd-notify
+        READY=1</command>. For details about the semantics of this
+        option see
+        <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>--pid=</option></term>
+
+        <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>
+
+      <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
+        STATUS=…</command>. For details about the semantics of this
+        option see
+        <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><option>--booted</option></term>
+
+        <listitem><para>Returns 0 if the system was booted up with
+        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>. 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" />
+      <xi:include href="standard-options.xml" xpointer="version" />
+    </variablelist>
+
+  </refsect1>
+
+  <refsect1>
+    <title>Exit status</title>
+
+    <para>On success, 0 is returned, a non-zero failure code
+    otherwise.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Example</title>
+
+    <example>
+      <title>Start-up Notification and Status Updates</title>
+
+      <para>A simple shell daemon that sends start-up notifications
+      after having set up its communication channel. During runtime it
+      sends further status updates to the init system:</para>
+
+      <programlisting>#!/bin/sh
+
+mkfifo /tmp/waldo
+systemd-notify --ready --status="Waiting for data…"
+
+while : ; do
+        read -r a &lt; /tmp/waldo
+        systemd-notify --status="Processing $a"
+
+        # Do something with $a …
+
+        systemd-notify --status="Waiting for data…"
+done</programlisting>
+    </example>
+  </refsect1>
+
+  <refsect1>
+    <title>See Also</title>
+    <para>
+      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    </para>
+  </refsect1>
+
+</refentry>