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| <!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"> |
| |
| <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.</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> |
| </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 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> |
| </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> |
| |
| <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/bash |
| |
| mkfifo /tmp/waldo |
| systemd-notify --ready --status="Waiting for data…" |
| |
| while : ; do |
| read a < /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> |