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diff --git a/man/sd-daemon.xml b/man/sd-daemon.xml new file mode 100644 index 0000000000..2acc021041 --- /dev/null +++ b/man/sd-daemon.xml @@ -0,0 +1,162 @@ +<?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 General Public License as published by + the Free Software Foundation; either version 2 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. + + You should have received a copy of the GNU General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +--> + +<refentry id="sd-daemon"> + + <refentryinfo> + <title>sd-daemon</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-daemon</refentrytitle> + <manvolnum>7</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd-daemon</refname> + <refpurpose>Reference implementation of APIs for + new-style daemons</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include "sd-daemon.h"</funcsynopsisinfo> + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><filename>sd-daemon.c</filename> and + <filename>sd-daemon.h</filename> provide a reference + implementation of various APIs for new-style daemons, + as implemented by the + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry> + init system.</para> + + <para>See + <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry> + for more information about the functions + implemented. In addition to these functions a couple + of logging prefixes are defined as macros:</para> + + <programlisting>#define SD_EMERG "<0>" /* system is unusable */ +#define SD_ALERT "<1>" /* action must be taken immediately */ +#define SD_CRIT "<2>" /* critical conditions */ +#define SD_ERR "<3>" /* error conditions */ +#define SD_WARNING "<4>" /* warning conditions */ +#define SD_NOTICE "<5>" /* normal but significant condition */ +#define SD_INFO "<6>" /* informational */ +#define SD_DEBUG "<7>" /* debug-level messages */</programlisting> + + <para>These prefixes are intended to be used in + conjunction with STDERR-based logging as implemented + by systemd. If a systemd service definition file is + configured with <varname>StandardError=syslog</varname> + or <varname>StandardError=kmsg</varname> these + prefixes can be used to encode a log level in lines + printed. This is similar to the kernel + <function>printk()</function>-style logging. See + <citerefentry><refentrytitle>klogctl</refentrytitle><manvolnum>2</manvolnum></citerefentry> + for more information.</para> + + <para>The log levels are identical to + <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>'s + log level system. To use these prefixes simply prefix + every line with one of these strings. A line that is + not prefixed will be logged at the default log level + SD_INFO.</para> + + <example> + <title>Hello World</title> + + <para>A daemon may log with the log level + NOTICE by issuing this call:</para> + + <programlisting>fprintf(stderr, SD_NOTICE "Hello World!\n");</programlisting> + </example> + </refsect1> + + <refsect1> + <title>Notes</title> + + <para>These interfaces 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. See the respective function man pages + for details.</para> + + <para>In addition, 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>These APIs are implemented in the reference + implementation's drop-in + <filename>sd-daemon.c</filename> and + <filename>sd-daemon.h</filename> files. It is + recommended that applications consuming these APIs copy + the implementation into their source tree, either + verbatim or in excerpts. These interfaces are + currently not available in a dynamic library.</para> + + <para>The functions directly related to new-style + daemons become NOPs when -DDISABLE_SYSTEMD is set + during compilation. In addition, if + <filename>sd-daemon.c</filename> is compiled on + non-Linux systems they become NOPs, too.</para> + </refsect1> + + <refsect1> + <title>See Also</title> + <para> + <citerefentry><refentrytitle>sd_listen_fds</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd_is_fifo</refentrytitle><manvolnum>3</manvolnum></citerefentry>, + <citerefentry><refentrytitle>daemon</refentrytitle><manvolnum>7</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>systemd.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>fprintf</refentrytitle><manvolnum>3</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |