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Diffstat (limited to 'man/sd_notify.xml')
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diff --git a/man/sd_notify.xml b/man/sd_notify.xml deleted file mode 100644 index 75edeeadf3..0000000000 --- a/man/sd_notify.xml +++ /dev/null @@ -1,319 +0,0 @@ -<?xml version='1.0'?> <!--*-nxml-*--> -<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" - "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> - -<!-- - 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/>. ---> - -<refentry id="sd_notify"> - - <refentryinfo> - <title>sd_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> - <refentrytitle>sd_notify</refentrytitle> - <manvolnum>3</manvolnum> - </refmeta> - - <refnamediv> - <refname>sd_notify</refname> - <refname>sd_notifyf</refname> - <refpurpose>Notify service manager about start-up completion and other daemon status changes</refpurpose> - </refnamediv> - - <refsynopsisdiv> - <funcsynopsis> - <funcsynopsisinfo>#include <systemd/sd-daemon.h></funcsynopsisinfo> - - <funcprototype> - <funcdef>int <function>sd_notify</function></funcdef> - <paramdef>int <parameter>unset_environment</parameter></paramdef> - <paramdef>const char *<parameter>state</parameter></paramdef> - </funcprototype> - - <funcprototype> - <funcdef>int <function>sd_notifyf</function></funcdef> - <paramdef>int <parameter>unset_environment</parameter></paramdef> - <paramdef>const char *<parameter>format</parameter></paramdef> - <paramdef>...</paramdef> - </funcprototype> - </funcsynopsis> - </refsynopsisdiv> - - <refsect1> - <title>Description</title> - <para><function>sd_notify()</function> shall be called - by a daemon to notify the init system about status - changes. It can be used to send arbitrary information, - encoded in an environment-block-like string. Most - importantly it can be used for start-up completion - notification.</para> - - <para>If the <parameter>unset_environment</parameter> - parameter is non-zero <function>sd_notify()</function> - will unset the <varname>$NOTIFY_SOCKET</varname> - environment variable before returning (regardless - whether the function call itself succeeded or - not). Further calls to - <function>sd_notify()</function> will then fail, but - the variable is no longer inherited by child - processes.</para> - - <para>The <parameter>state</parameter> parameter - 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 - assignments, but the following shall be considered - well-known:</para> - - <variablelist> - <varlistentry> - <term>READY=1</term> - - <listitem><para>Tells the init system - that daemon startup is finished. This - is only used by systemd if the service - definition file has Type=notify - set. The passed argument is a boolean - "1" or "0". Since there is little - value in signaling non-readiness, the - only value daemons should send is - "READY=1".</para></listitem> - </varlistentry> - - <varlistentry> - <term>STATUS=...</term> - - <listitem><para>Passes a single-line - status string back to the init system - that describes the daemon state. This - is free-form and can be used for - various purposes: general state - feedback, fsck-like programs could - pass completion percentages and - failing programs could pass a human - readable error message. Example: - "STATUS=Completed 66% of file system - check..."</para></listitem> - </varlistentry> - - <varlistentry> - <term>ERRNO=...</term> - - <listitem><para>If a daemon fails, the - errno-style error code, formatted as - string. Example: "ERRNO=2" for - ENOENT.</para></listitem> - </varlistentry> - - <varlistentry> - <term>BUSERROR=...</term> - - <listitem><para>If a daemon fails, the - D-Bus error-style error code. Example: - "BUSERROR=org.freedesktop.DBus.Error.TimedOut"</para></listitem> - </varlistentry> - - <varlistentry> - <term>MAINPID=...</term> - - <listitem><para>The main pid of the - daemon, in case the init system did - not fork off the process - 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_USEC=</varname> - environment variable has been set for - the service process, in every half the - time interval that is specified in the - variable.</para></listitem> - </varlistentry> - </variablelist> - - <para>It is recommended to prefix variable names that - are not shown in the list above with - <varname>X_</varname> to avoid namespace - clashes.</para> - - <para>Note that systemd will accept status data sent - from a daemon only if the - <varname>NotifyAccess=</varname> option is correctly - set in the service definition file. See - <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry> - for details.</para> - - <para><function>sd_notifyf()</function> is similar to - <function>sd_notify()</function> but takes a - <function>printf()</function>-like format string plus - arguments.</para> - </refsect1> - - <refsect1> - <title>Return Value</title> - - <para>On failure, these calls return a negative - 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 - 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 - 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> - - <para>Internally, these functions send a single - datagram with the state string as payload to the - AF_UNIX socket referenced in the - <varname>$NOTIFY_SOCKET</varname> environment - variable. If the first character of - <varname>$NOTIFY_SOCKET</varname> is @ 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/systemd/plain/src/libsystemd-daemon/sd-daemon.c"/> - and <ulink - url="http://cgit.freedesktop.org/systemd/systemd/plain/src/systemd/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>3</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> - <varlistentry> - <term><varname>$NOTIFY_SOCKET</varname></term> - - <listitem><para>Set by the init system - for supervised processes for status - and start-up completion - notification. This environment variable - specifies the socket - <function>sd_notify()</function> talks - to. See above for details.</para></listitem> - </varlistentry> - </variablelist> - </refsect1> - - <refsect1> - <title>Examples</title> - - <example> - <title>Start-up Notification</title> - - <para>When a daemon finished starting up, it - might issue the following call to notify - the init system:</para> - - <programlisting>sd_notify(0, "READY=1");</programlisting> - </example> - - <example> - <title>Extended Start-up Notification</title> - - <para>A daemon could send the following after - completing initialization:</para> - - <programlisting>sd_notifyf(0, "READY=1\n" - "STATUS=Processing requests...\n" - "MAINPID=%lu", - (unsigned long) getpid());</programlisting> - </example> - - <example> - <title>Error Cause Notification</title> - - <para>A daemon could send the following shortly before exiting, on failure</para> - - <programlisting>sd_notifyf(0, "STATUS=Failed to start up: %s\n" - "ERRNO=%i", - strerror(errno), - errno);</programlisting> - </example> - </refsect1> - - <refsect1> - <title>See Also</title> - <para> - <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</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> - </para> - </refsect1> - -</refentry> |