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diff --git a/man/sd_id128_randomize.xml b/man/sd_id128_randomize.xml new file mode 100644 index 0000000000..499c55fb60 --- /dev/null +++ b/man/sd_id128_randomize.xml @@ -0,0 +1,157 @@ +<?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 2012 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_id128_randomize"> + + <refentryinfo> + <title>sd_id128_randomize</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_id128_randomize</refentrytitle> + <manvolnum>3</manvolnum> + </refmeta> + + <refnamediv> + <refname>sd_id128_randomize</refname> + <refname>sd_id128_get_machine</refname> + <refname>sd_id128_get_boot</refname> + <refpurpose>Generate or retrieve 128 bit IDs</refpurpose> + </refnamediv> + + <refsynopsisdiv> + <funcsynopsis> + <funcsynopsisinfo>#include <systemd/sd-id128.h></funcsynopsisinfo> + + <funcprototype> + <funcdef>int <function>sd_id128_randomize</function></funcdef> + <paramdef>sd_id128_t* <parameter>ret</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_id128_get_machine</function></funcdef> + <paramdef>sd_id128_t* <parameter>ret</parameter></paramdef> + </funcprototype> + + <funcprototype> + <funcdef>int <function>sd_id128_get_boot</function></funcdef> + <paramdef>sd_id128_t* <parameter>ret</parameter></paramdef> + </funcprototype> + + </funcsynopsis> + </refsynopsisdiv> + + <refsect1> + <title>Description</title> + + <para><function>sd_id128_randomize()</function> + generates a new randomized 128 bit ID and returns it + in <parameter>ret</parameter>. Every invocation + returns a new randomly generated ID. This uses the + <filename>/dev/urandom</filename> kernel random number + generator.</para> + + <para><function>sd_id128_get_machine()</function> + returns the machine ID of the executing host. This + reads and parses the + <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> + file. This function caches the machine ID internally + to make retrieving the machine ID a cheap + operation.</para> + + <para><function>sd_id128_get_boot()</function> returns + the boot ID of the executing kernel. This reads and + parses the + <filename>/proc/sys/kernel/random/boot_id</filename> + file exposed by the kernel. It is randomly generated + early at boot and is unique for every running kernel + instance. See + <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> + for more information. This function also internally + caches the returned ID to make this call a cheap + operation.</para> + + <para>Note that + <function>sd_id128_randomize()</function> and + <function>sd_id128_get_boot()</function> always return + a UUID v4 compatible + ID. <function>sd_id128_get_machine()</function> will + also return a UUID v4 compatible ID on new + installations, but might not on older. It is possible + to convert the machine ID into an UUID v4 compatible + one. For more information see + <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para> + + <para>For more information about the + <literal>sd_id128_t</literal> type see + <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para> + + <para><citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s + <literal>--new-id</literal> command may be used as + command line front-end for + <function>sd_id128_randomize()</function>.</para> + </refsect1> + + <refsect1> + <title>Return Value</title> + + <para>The three calls returns 0 on success (in which + case <parameter>ret</parameter> is filled in), or a + negative errno-style error code.</para> + </refsect1> + + <refsect1> + <title>Notes</title> + + <para>The <function>sd_id128_randomize()</function>, + <function>sd_id128_get_machine()</function> and + <function>sd_id128_get_boot()</function> interfaces + are available as shared library, which can be compiled + and linked to with the + <literal>libsystemd-id128</literal> + <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> + file.</para> + </refsect1> + + <refsect1> + <title>See Also</title> + + <para> + <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, + <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>7</manvolnum></citerefentry>, + <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>, + <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry> + </para> + </refsect1> + +</refentry> |