forked from systemd/systemd
-
Notifications
You must be signed in to change notification settings - Fork 0
/
systemd-notify.xml
182 lines (144 loc) · 8.08 KB
/
systemd-notify.xml
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
<?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+ -->
<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 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>
<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>