Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ 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
- General Public License for more details.
+ Lesser General Public License for more details.
- You should have received a copy of the GNU General Public License
+ You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
-<refentry id="sd_notify">
+<refentry id="sd_notify"
+ xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>sd_notify</title>
<refnamediv>
<refname>sd_notify</refname>
<refname>sd_notifyf</refname>
- <refpurpose>Notify init system about start-up completion and other daemon status changes</refpurpose>
+ <refpurpose>Notify service manager about start-up completion and other daemon status changes</refpurpose>
</refnamediv>
<refsynopsisdiv>
notification.</para>
<para>If the <parameter>unset_environment</parameter>
- parameter is non-zero <function>sd_notify()</function>
+ parameter is non-zero, <function>sd_notify()</function>
will unset the <varname>$NOTIFY_SOCKET</varname>
- environment variable before returning (regardless
+ environment variable before returning (regardless of
whether the function call itself succeeded or
not). Further calls to
<function>sd_notify()</function> will then fail, but
processes.</para>
<para>The <parameter>state</parameter> parameter
- should contain an newline-separated list of variable
+ should contain a newline-separated list of variable
assignments, similar in style to an environment
block. A trailing newline is implied if none is
specified. The string may contain any kind of variable
definition file has Type=notify
set. The passed argument is a boolean
"1" or "0". Since there is little
- value in signalling non-readiness, the
+ value in signaling non-readiness, the
only value daemons should send is
"READY=1".</para></listitem>
</varlistentry>
itself. Example:
"MAINPID=4711"</para></listitem>
</varlistentry>
+
+ <varlistentry>
+ <term>WATCHDOG=1</term>
+
+ <listitem><para>Tells systemd to
+ update the watchdog timestamp. This is
+ the keep-alive ping that services need
+ to issue in regular intervals if
+ <varname>WatchdogSec=</varname> is
+ enabled for it. See
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ for details. It is recommended to send
+ this message if the
+ <varname>$WATCHDOG_PID</varname>
+ environment variable has been set to
+ the PID of the service process, in
+ every half the time interval that is
+ specified in the
+ <varname>$WATCHDOG_USEC</varname>
+ environment variable. See
+ <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for details.</para></listitem>
+ </varlistentry>
</variablelist>
<para>It is recommended to prefix variable names that
errno-style error code. If
<varname>$NOTIFY_SOCKET</varname> was not set and
hence no status data could be sent, 0 is returned. If
- the status was sent these functions return with a
+ the status was sent, these functions return with a
positive return value. In order to support both, init
systems that implement this scheme and those which
- don't, it is generally recommended to ignore the return
+ do not, it is generally recommended to ignore the return
value of this call.</para>
</refsect1>
<refsect1>
<title>Notes</title>
- <para>These functions are provided by the reference
- implementation of APIs for new-style daemons and
- distributed with the systemd package. The algorithms
- they implement are simple, and can easily be
- reimplemented in daemons if it is important to support
- this interface without using the reference
- implementation.</para>
+ <xi:include href="libsystemd-pkgconfig.xml" xpointer="pkgconfig-text"/>
<para>Internally, these functions send a single
datagram with the state string as payload to the
- AF_UNIX socket referenced in the
+ <constant>AF_UNIX</constant> socket referenced in the
<varname>$NOTIFY_SOCKET</varname> environment
variable. If the first character of
- <varname>$NOTIFY_SOCKET</varname> is @ the string is
+ <varname>$NOTIFY_SOCKET</varname> is <literal>@</literal>, the string is
understood as Linux abstract namespace socket. The
datagram is accompanied by the process credentials of
the sending daemon, using SCM_CREDENTIALS.</para>
-
- <para>For details about the algorithms check the
- liberally licensed reference implementation sources:
- <ulink url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.c"/>
- resp. <ulink
- url="http://cgit.freedesktop.org/systemd/tree/src/sd-daemon.h"/></para>
-
- <para><function>sd_notify()</function> and
- <function>sd_notifyf()</function> are implemented in
- the reference implementation's
- <filename>sd-daemon.c</filename> and
- <filename>sd-daemon.h</filename> files. These
- interfaces are available as shared library, which can
- be compiled and linked to with the
- <literal>libsystemd-daemon</literal>
- <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
- file. Alternatively, applications consuming these APIs
- may copy the implementation into their source tree. For
- more details about the reference implementation see
- <citerefentry><refentrytitle>sd_daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
-
- <para>If the reference implementation is used as
- drop-in files and -DDISABLE_SYSTEMD is set during
- compilation these functions will always return 0 and
- otherwise become a NOP.</para>
</refsect1>
<refsect1>
<title>Environment</title>
- <variablelist>
+ <variablelist class='environment-variables'>
<varlistentry>
<term><varname>$NOTIFY_SOCKET</varname></term>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd-daemon</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_watchdog_enabled</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
~ianmdlvl / elogind.git / blobdiff