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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
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4 | |
5 | <!-- | |
572eb058 | 6 | SPDX-License-Identifier: LGPL-2.1+ |
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7 | --> |
8 | ||
dfdebb1b | 9 | <refentry id="systemd-notify" |
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10 | xmlns:xi="http://www.w3.org/2001/XInclude"> |
11 | ||
12 | <refentryinfo> | |
13 | <title>systemd-notify</title> | |
14 | <productname>systemd</productname> | |
15 | ||
16 | <authorgroup> | |
17 | <author> | |
18 | <contrib>Developer</contrib> | |
19 | <firstname>Lennart</firstname> | |
20 | <surname>Poettering</surname> | |
21 | <email>lennart@poettering.net</email> | |
22 | </author> | |
23 | </authorgroup> | |
24 | </refentryinfo> | |
25 | ||
26 | <refmeta> | |
27 | <refentrytitle>systemd-notify</refentrytitle> | |
28 | <manvolnum>1</manvolnum> | |
29 | </refmeta> | |
30 | ||
31 | <refnamediv> | |
32 | <refname>systemd-notify</refname> | |
33 | <refpurpose>Notify service manager about start-up completion and other daemon status changes</refpurpose> | |
34 | </refnamediv> | |
35 | ||
36 | <refsynopsisdiv> | |
37 | <cmdsynopsis> | |
38 | <command>systemd-notify <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">VARIABLE=VALUE</arg></command> | |
39 | </cmdsynopsis> | |
40 | </refsynopsisdiv> | |
41 | ||
42 | <refsect1> | |
43 | <title>Description</title> | |
44 | ||
45 | <para><command>systemd-notify</command> may be called by daemon | |
46 | scripts to notify the init system about status changes. It can be | |
47 | used to send arbitrary information, encoded in an | |
b938cb90 | 48 | environment-block-like list of strings. Most importantly, it can be |
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49 | used for start-up completion notification.</para> |
50 | ||
51 | <para>This is mostly just a wrapper around | |
52 | <function>sd_notify()</function> and makes this functionality | |
53 | available to shell scripts. For details see | |
54 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
55 | </para> | |
56 | ||
57 | <para>The command line may carry a list of environment variables | |
58 | to send as part of the status update.</para> | |
59 | ||
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60 | <para>Note that systemd will refuse reception of status updates from this command unless |
61 | <varname>NotifyAccess=</varname> is set for the service unit this command is called from.</para> | |
62 | ||
63 | <para>Note that <function>sd_notify()</function> notifications may be attributed to units correctly only if either | |
64 | the sending process is still around at the time PID 1 processes the message, or if the sending process is | |
65 | explicitly runtime-tracked by the service manager. The latter is the case if the service manager originally forked | |
66 | off the process, i.e. on all processes that match <varname>NotifyAccess=</varname><option>main</option> or | |
67 | <varname>NotifyAccess=</varname><option>exec</option>. Conversely, if an auxiliary process of the unit sends an | |
68 | <function>sd_notify()</function> message and immediately exits, the service manager might not be able to properly | |
69 | attribute the message to the unit, and thus will ignore it, even if | |
70 | <varname>NotifyAccess=</varname><option>all</option> is set for it.</para> | |
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71 | |
72 | <para><command>systemd-notify</command> will first attempt to invoke <function>sd_notify()</function> pretending to | |
73 | have the PID of the invoking process. This will only succeed when invoked with sufficient privileges. On failure, | |
74 | it will then fall back to invoking it under its own PID. This behaviour is useful in order that when the tool is | |
75 | invoked from a shell script the shell process — and not the <command>systemd-notify</command> process — appears as | |
76 | sender of the message, which in turn is helpful if the shell process is the main process of a service, due to the | |
77 | limitations of <varname>NotifyAccess=</varname><option>all</option> described above.</para> | |
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78 | </refsect1> |
79 | ||
80 | <refsect1> | |
81 | <title>Options</title> | |
82 | ||
83 | <para>The following options are understood:</para> | |
84 | ||
85 | <variablelist> | |
86 | <varlistentry> | |
87 | <term><option>--ready</option></term> | |
88 | ||
89 | <listitem><para>Inform the init system about service start-up | |
90 | completion. This is equivalent to <command>systemd-notify | |
91 | READY=1</command>. For details about the semantics of this | |
92 | option see | |
93 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem> | |
94 | </varlistentry> | |
95 | ||
96 | <varlistentry> | |
97 | <term><option>--pid=</option></term> | |
98 | ||
99 | <listitem><para>Inform the init system about the main PID of | |
100 | the daemon. Takes a PID as argument. If the argument is | |
101 | omitted, the PID of the process that invoked | |
102 | <command>systemd-notify</command> is used. This is equivalent | |
103 | to <command>systemd-notify MAINPID=$PID</command>. For details | |
104 | about the semantics of this option see | |
105 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem> | |
106 | </varlistentry> | |
107 | ||
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108 | <varlistentry> |
109 | <term><option>--uid=</option><replaceable>USER</replaceable></term> | |
110 | ||
111 | <listitem><para>Set the user ID to send the notification from. Takes a UNIX user name or numeric UID. When | |
112 | specified the notification message will be sent with the specified UID as sender, in place of the user the | |
113 | command was invoked as. This option requires sufficient privileges in order to be able manipulate the user | |
114 | identity of the process.</para></listitem> | |
115 | </varlistentry> | |
116 | ||
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117 | <varlistentry> |
118 | <term><option>--status=</option></term> | |
119 | ||
120 | <listitem><para>Send a free-form status string for the daemon | |
121 | to the init systemd. This option takes the status string as | |
122 | argument. This is equivalent to <command>systemd-notify | |
1eecafb8 | 123 | STATUS=…</command>. For details about the semantics of this |
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124 | option see |
125 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem> | |
126 | </varlistentry> | |
127 | ||
128 | <varlistentry> | |
129 | <term><option>--booted</option></term> | |
130 | ||
131 | <listitem><para>Returns 0 if the system was booted up with | |
132 | systemd, non-zero otherwise. If this option is passed, no | |
133 | message is sent. This option is hence unrelated to the other | |
134 | options. For details about the semantics of this option, see | |
94f099d8 | 135 | <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>. An |
a8eaaee7 | 136 | alternate way to check for this state is to call |
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137 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
138 | with the <command>is-system-running</command> command. It will | |
139 | return <literal>offline</literal> if the system was not booted | |
140 | with systemd. </para></listitem> | |
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141 | </varlistentry> |
142 | ||
143 | <xi:include href="standard-options.xml" xpointer="help" /> | |
144 | <xi:include href="standard-options.xml" xpointer="version" /> | |
145 | </variablelist> | |
146 | ||
147 | </refsect1> | |
148 | ||
149 | <refsect1> | |
150 | <title>Exit status</title> | |
151 | ||
152 | <para>On success, 0 is returned, a non-zero failure code | |
153 | otherwise.</para> | |
154 | </refsect1> | |
155 | ||
156 | <refsect1> | |
157 | <title>Example</title> | |
158 | ||
159 | <example> | |
160 | <title>Start-up Notification and Status Updates</title> | |
161 | ||
162 | <para>A simple shell daemon that sends start-up notifications | |
163 | after having set up its communication channel. During runtime it | |
164 | sends further status updates to the init system:</para> | |
165 | ||
166 | <programlisting>#!/bin/bash | |
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167 | |
168 | mkfifo /tmp/waldo | |
1eecafb8 | 169 | systemd-notify --ready --status="Waiting for data…" |
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170 | |
171 | while : ; do | |
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172 | read a < /tmp/waldo |
173 | systemd-notify --status="Processing $a" | |
c61fbdfc | 174 | |
1eecafb8 | 175 | # Do something with $a … |
c61fbdfc | 176 | |
1eecafb8 | 177 | systemd-notify --status="Waiting for data…" |
c61fbdfc | 178 | done</programlisting> |
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179 | </example> |
180 | </refsect1> | |
181 | ||
182 | <refsect1> | |
183 | <title>See Also</title> | |
184 | <para> | |
185 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
186 | <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
187 | <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>, | |
188 | <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
189 | <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
190 | </para> | |
191 | </refsect1> | |
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192 | |
193 | </refentry> |