X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=man%2Fsd_id128_get_machine.xml;h=e7326422b5c9e6c4718dcbff428300d4f7e485c2;hb=a5c28308446550e0966825472babdf123fc976ac;hp=2ad1f8f728b3b54c8820b6e0c81d6a1e644467fd;hpb=798d3a524ea57aaf40cb53858aaa45ec702f012d;p=elogind.git

diff --git a/man/sd_id128_get_machine.xml b/man/sd_id128_get_machine.xml
index 2ad1f8f72..e7326422b 100644
--- a/man/sd_id128_get_machine.xml
+++ b/man/sd_id128_get_machine.xml
@@ -3,29 +3,29 @@
   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
 
 <!--
-  This file is part of systemd.
+  This file is part of elogind.
 
   Copyright 2012 Lennart Poettering
 
-  systemd is free software; you can redistribute it and/or modify it
+  elogind 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
+  elogind 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/>.
+  along with elogind; If not, see <http://www.gnu.org/licenses/>.
 -->
 
 <refentry id="sd_id128_get_machine">
 
   <refentryinfo>
     <title>sd_id128_get_machine</title>
-    <productname>systemd</productname>
+    <productname>elogind</productname>
 
     <authorgroup>
       <author>
@@ -44,35 +44,59 @@
 
   <refnamediv>
     <refname>sd_id128_get_machine</refname>
+    <refname>sd_id128_get_machine_app_specific</refname>
     <refname>sd_id128_get_boot</refname>
+    <refname>sd_id128_get_invocation</refname>
     <refpurpose>Retrieve 128-bit IDs</refpurpose>
   </refnamediv>
 
   <refsynopsisdiv>
     <funcsynopsis>
-      <funcsynopsisinfo>#include &lt;systemd/sd-id128.h&gt;</funcsynopsisinfo>
+      <funcsynopsisinfo>#include &lt;elogind/sd-id128.h&gt;</funcsynopsisinfo>
 
       <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_machine_app_specific</function></funcdef>
+        <paramdef>sd_id128_t <parameter>app_id</parameter></paramdef>
+        <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>
 
+      <funcprototype>
+        <funcdef>int <function>sd_id128_get_invocation</function></funcdef>
+        <paramdef>sd_id128_t *<parameter>ret</parameter></paramdef>
+      </funcprototype>
+
     </funcsynopsis>
   </refsynopsisdiv>
 
   <refsect1>
     <title>Description</title>
 
-    <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_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. This ID
+    may be used wherever a unique identifier for the local system is needed. However, it is recommended to use this ID
+    as-is only in trusted environments. In untrusted environments it is recommended to derive an application specific
+    ID from this machine ID, in an irreversable (cryptographically secure) way. To make this easy
+    <function>sd_id128_get_machine_app_specific()</function> is provided, see below.</para>
+
+    <para><function>sd_id128_get_machine_app_specific()</function> is similar to
+    <function>sd_id128_get_machine()</function>, but retrieves a machine ID that is specific to the application that is
+    identified by the indicated application ID. It is recommended to use this function instead of
+    <function>sd_id128_get_machine()</function> when passing an ID to untrusted environments, in order to make sure
+    that the original machine ID may not be determined externally. The application-specific ID should be generated via
+    a tool like <command>journalctl --new-id128</command>, and may be compiled into the application. This function will
+    return the same application-specific ID for each combination of machine ID and application ID. Internally, this
+    function calculates HMAC-SHA256 of the application ID, keyed by the machine ID.</para>
 
     <para><function>sd_id128_get_boot()</function> returns the boot ID
     of the executing kernel. This reads and parses the
@@ -83,12 +107,16 @@
     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_get_boot()</function> always
-    returns 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 a UUID v4-compatible
-    one. For more information, see
+    <para><function>sd_id128_get_invocation()</function> returns the invocation ID of the currently executed
+    service. In its current implementation, this reads and parses the <varname>$INVOCATION_ID</varname> environment
+    variable that the service manager sets when activating a service, see
+    <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details. The
+    ID is cached internally. In future a different mechanism to determine the invocation ID may be added.</para>
+
+    <para>Note that <function>sd_id128_get_machine_app_specific()</function>, <function>sd_id128_get_boot()</function>
+    and <function>sd_id128_get_invocation()</function> always return UUID v4 compatible IDs.
+    <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 a 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>
@@ -107,11 +135,33 @@
   <refsect1>
     <title>Notes</title>
 
-    <para>The <function>sd_id128_get_machine()</function> and
-    <function>sd_id128_get_boot()</function> interfaces are available
-    as a shared library, which can be compiled and linked to with the
-    <literal>libsystemd</literal> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
-    file.</para>
+    <para>The <function>sd_id128_get_machine()</function>, <function>sd_id128_get_machine_app_specific()</function>
+    <function>sd_id128_get_boot()</function> and <function>sd_id128_get_invocation()</function> interfaces are
+    available as a shared library, which can be compiled and linked to with the
+    <literal>libsystemd</literal> <citerefentry
+    project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> file.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Examples</title>
+
+    <example>
+      <title>Application-specific machine ID</title>
+
+      <para>Here's a simple example for an application specific machine ID:</para>
+
+      <programlisting>#include &lt;systemd/sd-id128.h&gt;
+#include &lt;stdio.h&gt;
+
+#define OUR_APPLICATION_ID SD_ID128_MAKE(c2,73,27,73,23,db,45,4e,a6,3b,b9,6e,79,b5,3e,97)
+
+int main(int argc, char *argv[]) {
+        sd_id128_t id;
+        sd_id128_get_machine_app_specific(OUR_APPLICATION_ID, &amp;id);
+        printf("Our application ID: " SD_ID128_FORMAT_STR "\n", SD_ID128_FORMAT_VAL(id));
+        return 0;
+}</programlisting>
+    </example>
   </refsect1>
 
   <refsect1>
@@ -121,8 +171,9 @@
       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
-      <citerefentry><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry>,
-      <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+      <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry project='man-pages'><refentrytitle>random</refentrytitle><manvolnum>4</manvolnum></citerefentry>
     </para>
   </refsect1>