man: add description of org.freedesktop.LogControl1

I'm not sure if the LogTarget property is sufficiently general to be made into
a property that can be generally implemented. It is very closely tied to the internal
systemd logic. The other two seem fine thoough.

man/org.freedesktop.LogControl1.xml

@@ -0,0 +1,106 @@
+<?xml version='1.0'?>
+<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
+  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" >
+<!-- SPDX-License-Identifier: LGPL-2.1+ -->
+
+<refentry id="org.freedesktop.LogControl1"
+    xmlns:xi="http://www.w3.org/2001/XInclude">
+  <refentryinfo>
+    <title>org.freedesktop.LogControl1</title>
+    <productname>systemd</productname>
+  </refentryinfo>
+
+  <refmeta>
+    <refentrytitle>org.freedesktop.LogControl1</refentrytitle>
+    <manvolnum>5</manvolnum>
+  </refmeta>
+
+  <refnamediv>
+    <refname>org.freedesktop.LogControl1</refname>
+    <refpurpose>D-Bus interface to query and set logging configuration</refpurpose>
+  </refnamediv>
+
+  <refsect1>
+    <title>Introduction</title>
+
+    <para><interfacename>org.freedesktop.LogControl1</interfacename> is a generic interface that is intended
+    to be used by any daemon which should allow setting the log level and target over D-Bus. It is implemented
+    by various daemons that are part of the
+    <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> suite.</para>
+
+    <para>It is assumed that those settings are global for the whole program, so a fixed object path is
+    used. The interface should always be available under the path
+    <filename>/org/freedesktop/LogControl1</filename>.</para>
+  </refsect1>
+
+  <refsect1>
+    <title>Description</title>
+
+    <para>The following interface is exposed:</para>
+
+    <programlisting executable="systemd" node="/org/freedesktop/LogControl1" interface="org.freedesktop.LogControl1">
+node /org/freedesktop/LogControl1 {
+  interface org.freedesktop.LogControl1 {
+    properties:
+      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
+      @org.freedesktop.systemd1.Privileged("true")
+      readwrite s LogLevel = '...';
+      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
+      @org.freedesktop.systemd1.Privileged("true")
+      readwrite s LogTarget = '...';
+      @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
+      readonly s SyslogIdentifier = '...';
+  };
+  interface org.freedesktop.DBus.Peer { ... };
+  interface org.freedesktop.DBus.Introspectable { ... };
+  interface org.freedesktop.DBus.Properties { ... };
+};
+    </programlisting>
+
+    <!--Autogenerated cross-references for systemd.directives, do not edit-->
+
+    <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.LogControl1"/>
+
+    <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.LogControl1"/>
+
+    <variablelist class="dbus-property" generated="True" extra-ref="LogLevel"/>
+
+    <variablelist class="dbus-property" generated="True" extra-ref="LogTarget"/>
+
+    <variablelist class="dbus-property" generated="True" extra-ref="SyslogIdentifier"/>
+
+    <!--End of Autogenerated section-->
+
+    <refsect2>
+      <title>Properties</title>
+
+      <para><varname>LogLevel</varname> describes the
+      <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>-style
+      log-level, and should be one of <literal>emerg</literal>, <literal>alert</literal>,
+      <literal>crit</literal>, <literal>err</literal>, <literal>warning</literal>, <literal>notice</literal>,
+      <literal>info</literal>, <literal>debug</literal>, in order of increasing verbosity.</para>
+
+      <para><varname>LogTarget</varname> describes the log target (mechanism). It should be one of
+      <literal>console</literal> (log to the console or standard output),
+      <literal>kmsg</literal> (log to the kernel ring buffer),
+      <literal>journal</literal> (log the the journal natively, see
+      <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>),
+      <literal>syslog</literal> (log using the
+      <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> call).
+      </para>
+
+      <para>Those two properties are writable, so they may be set by sufficiently privileged users.</para>
+
+      <para><varname>SyslogIdentifier</varname> is a read-only property that shows the "syslog identifier".
+      It is a short string that identifies the program that is the source of log messages that is passed to
+      the <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry> call.
+      </para>
+
+      <para>Note: <command>journalctl</command> option <option>-p</option>/<option>--priority=</option> may
+      be used to filter log messages by log level, option <option>-t</option>/<option>--identifier=</option>
+      may be used to by the syslog identifier, and filters like <literal>_TRANSPORT=syslog</literal>,
+      <literal>_TRANSPORT=journal</literal>, and <literal>_TRANSPORT=kernel</literal> may be used to filter
+      messages by the mechanism through which they reached <command>systemd-journald</command>.</para>
+    </refsect2>
+  </refsect1>
+</refentry>

man/rules/meson.build

@@ -44,6 +44,7 @@ manpages = [
  ['nss-mymachines', '8', ['libnss_mymachines.so.2'], 'ENABLE_NSS_MYMACHINES'],
  ['nss-resolve', '8', ['libnss_resolve.so.2'], 'ENABLE_NSS_RESOLVE'],
  ['nss-systemd', '8', ['libnss_systemd.so.2'], 'ENABLE_NSS_SYSTEMD'],
+ ['org.freedesktop.LogControl1', '5', [], ''],
  ['org.freedesktop.hostname1', '5', [], 'ENABLE_HOSTNAMED'],
  ['org.freedesktop.import1', '5', [], 'ENABLE_IMPORTD'],
  ['org.freedesktop.locale1', '5', [], 'ENABLE_LOCALED'],

man/systemd-hostnamed.service.xml

@@ -56,7 +56,9 @@
     is a command line client to this service.</para>
 
     <para>See
-    <citerefentry><refentrytitle>org.freedesktop.hostname1</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+    <citerefentry><refentrytitle>org.freedesktop.hostname1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
     for a description of the D-Bus API.</para>
   </refsect1>
 

man/systemd-importd.service.xml

@@ -36,10 +36,11 @@
     <command>pull-raw</command>, <command>pull-tar</command>, <command>import-raw</command>,
     <command>import-tar</command>, <command>export-raw</command>, and <command>export-tar</command> commands.</para>
 
-    <para>See the
+    <para>See
-    <ulink url="https://www.freedesktop.org/wiki/Software/systemd/importd">
+    <citerefentry><refentrytitle>org.freedesktop.import1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
-    importd D-Bus API Documentation</ulink> for information about the
+    and
-    APIs <filename>systemd-importd</filename> provides.</para>
+    <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    for a description of the D-Bus API.</para>
   </refsect1>
 
   <refsect1>

man/systemd-localed.service.xml

@@ -41,7 +41,9 @@
     is a command line client to this service.</para>
 
     <para>See
-    <citerefentry><refentrytitle>org.freedesktop.locale1</refentrytitle><manvolnum>1</manvolnum></citerefentry>
+    <citerefentry><refentrytitle>org.freedesktop.locale1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
     for a description of the D-Bus API.</para>
   </refsect1>
 

man/systemd-logind.service.xml

@@ -79,7 +79,9 @@
     such as users, sessions and seats.</para>
 
     <para>See
-    <citerefentry><refentrytitle>org.freedesktop.login1</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+    <citerefentry><refentrytitle>org.freedesktop.login1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
     for information about the D-Bus APIs <filename>systemd-logind</filename> provides.</para>
 
     <para>For more information on the inhibition logic see the <ulink

man/systemd-machined.service.xml

@@ -107,7 +107,9 @@
     For more information please consult
     <citerefentry><refentrytitle>sd-login</refentrytitle><manvolnum>3</manvolnum></citerefentry>
     and
-    <citerefentry><refentrytitle>org.freedesktop.machine1</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+    <citerefentry><refentrytitle>org.freedesktop.machine1</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+    and
+    <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
     </para>
 
     <para>A small companion daemon

man/systemd-resolved.service.xml

@@ -38,6 +38,8 @@
       <listitem><para>The native, fully-featured API <command>systemd-resolved</command> exposes on the bus,
       see
       <citerefentry><refentrytitle>org.freedesktop.resolve1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+      and
+      <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
       for details. Usage of this API is generally recommended to clients as it is asynchronous and fully
       featured (for example, properly returns DNSSEC validation status and interface scope for addresses as
       necessary for supporting link-local networking).</para></listitem>

man/systemd-timedated.service.xml

@@ -55,6 +55,8 @@
 
     <para>See
     <citerefentry><refentrytitle>org.freedesktop.timedate1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
     for information about the D-Bus API.</para>
   </refsect1>
 

man/systemd.xml

@@ -281,7 +281,10 @@
     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
 
     <para>The D-Bus API of <command>systemd</command> is described in
-    <citerefentry><refentrytitle>org.freedesktop.systemd1</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
+    <citerefentry><refentrytitle>org.freedesktop.systemd1</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+    and
+    <citerefentry><refentrytitle>org.freedesktop.LogControl1</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
+    </para>
 
     <para>Systems which invoke systemd in a container or initrd environment should implement the <ulink
     url="https://systemd.io/CONTAINER_INTERFACE">Container Interface</ulink> or <ulink