man: document libsystemd-id128

4 files changed, 459 insertions, 1 deletions

diff --git a/man/machine-id.xml b/man/machine-id.xml
index 73f0926c0b..a42c7bb5ac 100644
--- a/man/machine-id.xml
+++ b/man/machine-id.xml
@@ -136,7 +136,9 @@ id[8] = (id[8] &amp; 0x3F) | 0x80;</programlisting>
                           <citerefentry><refentrytitle>gethostid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                           <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-                          <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+                          <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+                          <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
                   </para>
         </refsect1>
 
diff --git a/man/sd-id128.xml b/man/sd-id128.xml
new file mode 100644
index 0000000000..cbc130d751
--- /dev/null
+++ b/man/sd-id128.xml
@@ -0,0 +1,168 @@
+<?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">
+
+        <refentryinfo>
+                <title>sd-id128</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</refentrytitle>
+                <manvolnum>7</manvolnum>
+        </refmeta>
+
+        <refnamediv>
+                <refname>sd-id128</refname>
+                <refname>sd_id128_t</refname>
+                <refname>SD_ID128_MAKE</refname>
+                <refname>SD_ID128_FORMAT_STR</refname>
+                <refname>SD_ID128_FORMAT_VAL</refname>
+                <refname>sd_id128_equal</refname>
+                <refpurpose>APIs for processing 128 bit IDs</refpurpose>
+        </refnamediv>
+
+        <refsynopsisdiv>
+                <funcsynopsis>
+                        <funcsynopsisinfo>#include &lt;systemd/sd-id128.h&gt;</funcsynopsisinfo>
+                </funcsynopsis>
+
+                <cmdsynopsis>
+                        <command>pkg-config --cflags --libs libsystemd-id128</command>
+                </cmdsynopsis>
+
+        </refsynopsisdiv>
+
+        <refsect1>
+                <title>Description</title>
+
+                <para><filename>sd-id128.h</filename> provides APIs to
+                process and generate 128 bit ID values. The 128 bit ID
+                values processed and generated by these APIs are a
+                generalization of OSF UUIDs as defined by <ulink
+                url="http://tools.ietf.org/html/rfc4122">RFC
+                4122</ulink>, though use a simpler string
+                formatting. These functions impose no structure on the
+                used IDs, much unlike OSF UUIDs or Microsoft GUIDs,
+                but are fully compatible with those types of IDs.
+                </para>
+
+                <para>See
+                <citerefentry><refentrytitle>sd_id128_to_string</refentrytitle><manvolnum>3</manvolnum></citerefentry> and
+                <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+                for more information about the functions
+                implemented.</para>
+
+                <para>A 128 bit ID is implemented as the following
+                union type:</para>
+
+                <programlisting>typedef union sd_id128 {
+        uint8_t bytes[16];
+        uint64_t qwords[2];
+} sd_id128_t;</programlisting>
+
+                <para>This union type allows accessing the 128 bit ID
+                as 16 separate bytes or 2 64 bit words. It is generally
+                safer to access the ID components by their 8 bit array
+                to avoid endianess issues. This union is intended to
+                be passed call-by-value (as opposed to
+                call-by-reference) and may be directly manipulated by
+                clients.</para>
+
+                <para>A couple of macros are defined to denote and
+                decode 128 bit IDs:</para>
+
+                <para><function>SD_ID128_MAKE()</function> may be used
+                to write a 128 bit ID in source code. A commonly used
+                idiom is to give 128 bit IDs names using this macro:</para>
+
+                <programlisting>#define SD_MESSAGE_COREDUMP SD_ID128_MAKE(fc,2e,22,bc,6e,e6,47,b6,b9,07,29,ab,34,a2,50,b1)</programlisting>
+
+                <para><function>SD_ID128_FORMAT_STR</function> and
+                <function>SD_ID128_FORMAT_VAL()</function> may be used
+                to format a 128 bit ID in a
+                <citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+                format string, as shown in the following
+                example:</para>
+
+                <programlisting>int main(int argc, char *argv[]) {
+        sd_id128_t id;
+        id = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07);
+        printf("The ID encoded in this C file is " SD_ID128_FORMAT_STR ".\n", SD_ID128_FORMAT_VAL(id));
+        return 0;
+}</programlisting>
+
+                <para>Use <function>sd_id128_equal()</function> to compare two 128 bit IDs:</para>
+
+                <programlisting>int main(int argc, char *argv[]) {
+        sd_id128_t a, b, c;
+        a = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07);
+        b = SD_ID128_MAKE(f2,28,88,9c,5f,09,44,15,9d,d7,04,77,58,cb,e7,3e);
+        c = a;
+        assert(sd_id128_equal(a, c));
+        assert(!sd_id128_equal(a, b));
+        return 0;
+}</programlisting>
+
+                <para>Note that new, randomized IDs may be generated
+                with
+                <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
+                <literal>--new-id</literal> command.</para>
+        </refsect1>
+
+        <refsect1>
+                <title>Notes</title>
+
+                <para>These APIs are implemented 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_to_string</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+                        <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+                </para>
+        </refsect1>
+
+</refentry>
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 &lt;systemd/sd-id128.h&gt;</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>
diff --git a/man/sd_id128_to_string.xml b/man/sd_id128_to_string.xml
new file mode 100644
index 0000000000..3a171550e9
--- /dev/null
+++ b/man/sd_id128_to_string.xml
@@ -0,0 +1,131 @@
+<?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_to_string">
+
+        <refentryinfo>
+                <title>sd_id128_to_string</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_to_string</refentrytitle>
+                <manvolnum>3</manvolnum>
+        </refmeta>
+
+        <refnamediv>
+                <refname>sd_id128_to_string</refname>
+                <refname>sd_id128_from_string</refname>
+                <refpurpose>Format or parse 128 bit IDs as strings</refpurpose>
+        </refnamediv>
+
+        <refsynopsisdiv>
+                <funcsynopsis>
+                        <funcsynopsisinfo>#include &lt;systemd/sd-id128.h&gt;</funcsynopsisinfo>
+
+                        <funcprototype>
+                                <funcdef>char* <function>sd_id128_to_string</function></funcdef>
+                                <paramdef>sd_id128_t <parameter>id</parameter>, char <parameter>s</parameter>[33]</paramdef>
+                        </funcprototype>
+
+                        <funcprototype>
+                                <funcdef>int <function>sd_id128_from_string</function></funcdef>
+                                <paramdef>const char <parameter>s</parameter>[33], sd_id128_t* <parameter>ret</parameter></paramdef>
+                        </funcprototype>
+
+                </funcsynopsis>
+        </refsynopsisdiv>
+
+        <refsect1>
+                <title>Description</title>
+
+                <para><function>sd_id128_to_string()</function>
+                formats a 128 bit ID as character string. It expects
+                the ID and a string array capable of storing 33
+                characters. The ID will be formatted as 32 lowercase
+                hexadecimal digits and be terminated by a NUL
+                byte.</para>
+
+                <para><function>sd_id128_from_string()</function>
+                implements the reverse operation: it takes a 33
+                character array with 32 hexadecimial digits
+                (terminated by NUL) and parses them back into an
+                128 bit ID returned in
+                <parameter>ret</parameter>.</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>When formatting a 128 bit ID into a string it is
+                often easier to use a format string for
+                <citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>. This
+                is easly done using the
+                <function>SD_ID128_FORMAT_STR</function> and
+                <function>SD_ID128_FORMAT_VAL()</function> macros. For
+                more information see
+                <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+        </refsect1>
+
+        <refsect1>
+                <title>Return Value</title>
+
+                <para><function>sd_id128_to_string()</function> always
+                succeeds and returns a pointer to the string array
+                passed in.  <function>sd_id128_from_string</function>
+                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_to_string()</function>
+                and <function>sd_id128_from_string()</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>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+                </para>
+        </refsect1>
+
+</refentry>