<?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+
-
- 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/>.
--->
+<!-- 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>
-
- <authorgroup>
- <author>
- <contrib>Developer</contrib>
- <firstname>Lennart</firstname>
- <surname>Poettering</surname>
- <email>lennart@poettering.net</email>
- </author>
- </authorgroup>
</refentryinfo>
<refmeta>
<cmdsynopsis>
<command>systemd-notify <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">VARIABLE=VALUE</arg></command>
</cmdsynopsis>
+ <cmdsynopsis>
+ <command>systemd-notify --exec <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">VARIABLE=VALUE</arg> ; <arg rep="repeat">CMDLINE</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><command>systemd-notify</command> may be called by service scripts to notify the invoking service
+ manager 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
+ <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>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.</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>
+ <varname>NotifyAccess=</varname> is appropriately set for the service unit this command is called
+ from. See
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+ details.</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 the service manager 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. To address this
+ <command>systemd-notify</command> will wait until the notification message has been processed by the
+ service manager. When <option>--no-block</option> is used, this 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><command>systemd-notify</command> will first attempt to invoke <function>sd_notify()</function>
+ pretending to have the PID of the parent process of <command>systemd-notify</command> (i.e. 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>--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
+ <listitem><para>Inform the invoking service manager about service start-up or configuration reload
+ 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>--reloading</option></term>
+
+ <listitem><para>Inform the invoking service manager about the beginning of a configuration reload
+ cycle. This is equivalent to <command>systemd-notify RELOADING=1</command> (but implicitly also sets
+ a <varname>MONOTONIC_USEC=</varname> field as required for <varname>Type=notify-reload</varname>
+ services, see
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details). For details about the semantics of this option see
+ <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+
+ <xi:include href="version-info.xml" xpointer="v253"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>--stopping</option></term>
+
+ <listitem><para>Inform the invoking service manager about the beginning of the shutdown phase of the
+ service. This is equivalent to <command>systemd-notify STOPPING=1</command>. For details about the
+ semantics of this option see
+ <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+
+ <xi:include href="version-info.xml" xpointer="v253"/></listitem>
+ </varlistentry>
+
<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=$PID</command>. For details
- about the semantics of this option see
- <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
+ <listitem><para>Inform the service manager about the main PID of the service. Takes a PID as
+ argument. If the argument is specified as <literal>auto</literal> or omitted, the PID of the process
+ that invoked <command>systemd-notify</command> is used, except if that's the service manager. If the
+ argument is specified as <literal>self</literal>, the PID of the <command>systemd-notify</command>
+ command itself is used, and if <literal>parent</literal> is specified the calling process' PID is
+ used — even if it is the service manager. The latter is equivalent to <command>systemd-notify
+ MAINPID=$PID</command>. For details about the semantics of this option see
+ <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
+
+ <para>If this switch is used in an <command>systemd-notify</command> invocation from a process that
+ shall become the new main process of a service — and which is not the process forked off by the
+ service manager (or the current main process) —, then it is essential to set
+ <varname>NotifyAccess=all</varname> in the service unit file, or otherwise the notification will be
+ ignored for security reasons. See
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details.</para></listitem>
</varlistentry>
<varlistentry>
<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>
+ identity of the process.</para>
+
+ <xi:include href="version-info.xml" xpointer="v237"/></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>
+ <listitem><para>Send a free-form human readable status string for the daemon to the service
+ manager. 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>. This
+ information is shown in
+ <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
+ <command>status</command> output, among other places.</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
+ <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>
+ <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>
+
+ <xi:include href="version-info.xml" xpointer="v246"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>--exec</option></term>
+
+ <listitem><para>If specified <command>systemd-notify</command> will execute another command line
+ after it completed its operation, replacing its own process. If used, the list of assignments to
+ include in the message sent must be followed by a <literal>;</literal> character (as separate
+ argument), followed by the command line to execute. This permits "chaining" of commands, i.e. issuing
+ one operation, followed immediately by another, without changing PIDs.</para>
+
+ <para>Note that many shells interpret <literal>;</literal> as their own separator for command lines,
+ hence when <command>systemd-notify</command> is invoked from a shell the semicolon must usually be
+ escaped as <literal>\;</literal>.</para>
+
+ <xi:include href="version-info.xml" xpointer="v254"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>--fd=</option></term>
+
+ <listitem><para>Send a file descriptor along with the notification message. This is useful when
+ invoked in services that have the <varname>FileDescriptorStoreMax=</varname> setting enabled, see
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details. The specified file descriptor must be passed to <command>systemd-notify</command> when
+ invoked. This option may be used multiple times to pass multiple file descriptors in a single
+ notification message.</para>
+
+ <para>To use this functionality from a
+ <citerefentry project='man-pages'><refentrytitle>bash</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+ shell, use an expression like the following:</para>
+ <programlisting>systemd-notify --fd=4 --fd=5 4</some/file 5</some/other/file</programlisting>
+
+ <xi:include href="version-info.xml" xpointer="v254"/></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>--fdname=</option></term>
+
+ <listitem><para>Set a name to assign to the file descriptors passed via <option>--fd=</option> (see
+ above). This controls the <literal>FDNAME=</literal> field. This setting may only be specified once,
+ and applies to all file descriptors passed. Invoke this tool multiple times in case multiple file
+ descriptors with different file descriptor names shall be submitted.</para>
+
+ <xi:include href="version-info.xml" xpointer="v254"/></listitem>
</varlistentry>
<xi:include href="standard-options.xml" xpointer="help" />
<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>
+ <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/bash
+ <programlisting>#!/bin/sh
mkfifo /tmp/waldo
systemd-notify --ready --status="Waiting for data…"
while : ; do
- read a < /tmp/waldo
+ read -r a < /tmp/waldo
systemd-notify --status="Processing $a"
# Do something with $a …
<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>systemd.service</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>
projects / thirdparty / systemd.git / blobdiff