man/org.freedesktop.hostname1.xml

   1 <?xml version="1.0"?>
   2 <!--*-nxml-*-->
   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   4   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
   5 <!ENTITY % entities SYSTEM "custom-entities.ent" >
   6 %entities;
   7 ]>
   8 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   9
  10 <refentry id="org.freedesktop.hostname1" conditional='ENABLE_HOSTNAMED'
  11     xmlns:xi="http://www.w3.org/2001/XInclude">
  12   <refentryinfo>
  13     <title>org.freedesktop.hostname1</title>
  14     <productname>systemd</productname>
  15   </refentryinfo>
  16
  17   <refmeta>
  18     <refentrytitle>org.freedesktop.hostname1</refentrytitle>
  19     <manvolnum>5</manvolnum>
  20   </refmeta>
  21
  22   <refnamediv>
  23     <refname>org.freedesktop.hostname1</refname>
  24     <refpurpose>The D-Bus interface of systemd-hostnamed</refpurpose>
  25   </refnamediv>
  26
  27   <refsect1>
  28     <title>Introduction</title>
  29
  30     <para>
  31     <citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  32     is a system service that can be used to control the hostname and related machine metadata from user
  33     programs. This page describes the hostname semantics and the D-Bus interface.</para>
  34   </refsect1>
  35
  36   <refsect1>
  37     <title>The D-Bus API</title>
  38
  39     <para>The service exposes the following interfaces on the bus:</para>
  40
  41     <programlisting executable="systemd-hostnamed" node="/org/freedesktop/hostname1" interface="org.freedesktop.hostname1">
  42 node /org/freedesktop/hostname1 {
  43   interface org.freedesktop.hostname1 {
  44     methods:
  45       SetHostname(in  s hostname,
  46                   in  b interactive);
  47       SetStaticHostname(in  s hostname,
  48                         in  b interactive);
  49       SetPrettyHostname(in  s hostname,
  50                         in  b interactive);
  51       SetIconName(in  s icon,
  52                   in  b interactive);
  53       SetChassis(in  s chassis,
  54                  in  b interactive);
  55       SetDeployment(in  s deployment,
  56                     in  b interactive);
  57       SetLocation(in  s location,
  58                   in  b interactive);
  59       GetProductUUID(in  b interactive,
  60                      out ay uuid);
  61       GetHardwareSerial(out s serial);
  62       Describe(out s json);
  63     properties:
  64       readonly s Hostname = '...';
  65       readonly s StaticHostname = '...';
  66       readonly s PrettyHostname = '...';
  67       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  68       readonly s DefaultHostname = '...';
  69       readonly s HostnameSource = '...';
  70       readonly s IconName = '...';
  71       readonly s Chassis = '...';
  72       readonly s Deployment = '...';
  73       readonly s Location = '...';
  74       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  75       readonly s KernelName = '...';
  76       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  77       readonly s KernelRelease = '...';
  78       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  79       readonly s KernelVersion = '...';
  80       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  81       readonly s OperatingSystemPrettyName = '...';
  82       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  83       readonly s OperatingSystemCPEName = '...';
  84       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  85       readonly t OperatingSystemSupportEnd = ...;
  86       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  87       readonly s HomeURL = '...';
  88       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  89       readonly s HardwareVendor = '...';
  90       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  91       readonly s HardwareModel = '...';
  92       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  93       readonly s FirmwareVersion = '...';
  94       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  95       readonly s FirmwareVendor = '...';
  96       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  97       readonly t FirmwareDate = ...;
  98       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
  99       readonly ay MachineID = [...];
 100       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
 101       readonly ay BootID = [...];
 102       @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
 103       readonly u VSockCID = ...;
 104   };
 105   interface org.freedesktop.DBus.Peer { ... };
 106   interface org.freedesktop.DBus.Introspectable { ... };
 107   interface org.freedesktop.DBus.Properties { ... };
 108 };
 109     </programlisting>
 110
 111     <!--Autogenerated cross-references for systemd.directives, do not edit-->
 112
 113     <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.hostname1"/>
 114
 115     <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.hostname1"/>
 116
 117     <variablelist class="dbus-method" generated="True" extra-ref="SetHostname()"/>
 118
 119     <variablelist class="dbus-method" generated="True" extra-ref="SetStaticHostname()"/>
 120
 121     <variablelist class="dbus-method" generated="True" extra-ref="SetPrettyHostname()"/>
 122
 123     <variablelist class="dbus-method" generated="True" extra-ref="SetIconName()"/>
 124
 125     <variablelist class="dbus-method" generated="True" extra-ref="SetChassis()"/>
 126
 127     <variablelist class="dbus-method" generated="True" extra-ref="SetDeployment()"/>
 128
 129     <variablelist class="dbus-method" generated="True" extra-ref="SetLocation()"/>
 130
 131     <variablelist class="dbus-method" generated="True" extra-ref="GetProductUUID()"/>
 132
 133     <variablelist class="dbus-method" generated="True" extra-ref="GetHardwareSerial()"/>
 134
 135     <variablelist class="dbus-method" generated="True" extra-ref="Describe()"/>
 136
 137     <variablelist class="dbus-property" generated="True" extra-ref="Hostname"/>
 138
 139     <variablelist class="dbus-property" generated="True" extra-ref="StaticHostname"/>
 140
 141     <variablelist class="dbus-property" generated="True" extra-ref="PrettyHostname"/>
 142
 143     <variablelist class="dbus-property" generated="True" extra-ref="DefaultHostname"/>
 144
 145     <variablelist class="dbus-property" generated="True" extra-ref="HostnameSource"/>
 146
 147     <variablelist class="dbus-property" generated="True" extra-ref="IconName"/>
 148
 149     <variablelist class="dbus-property" generated="True" extra-ref="Chassis"/>
 150
 151     <variablelist class="dbus-property" generated="True" extra-ref="Deployment"/>
 152
 153     <variablelist class="dbus-property" generated="True" extra-ref="Location"/>
 154
 155     <variablelist class="dbus-property" generated="True" extra-ref="KernelName"/>
 156
 157     <variablelist class="dbus-property" generated="True" extra-ref="KernelRelease"/>
 158
 159     <variablelist class="dbus-property" generated="True" extra-ref="KernelVersion"/>
 160
 161     <variablelist class="dbus-property" generated="True" extra-ref="OperatingSystemPrettyName"/>
 162
 163     <variablelist class="dbus-property" generated="True" extra-ref="OperatingSystemCPEName"/>
 164
 165     <variablelist class="dbus-property" generated="True" extra-ref="OperatingSystemSupportEnd"/>
 166
 167     <variablelist class="dbus-property" generated="True" extra-ref="HomeURL"/>
 168
 169     <variablelist class="dbus-property" generated="True" extra-ref="HardwareVendor"/>
 170
 171     <variablelist class="dbus-property" generated="True" extra-ref="HardwareModel"/>
 172
 173     <variablelist class="dbus-property" generated="True" extra-ref="FirmwareVersion"/>
 174
 175     <variablelist class="dbus-property" generated="True" extra-ref="FirmwareVendor"/>
 176
 177     <variablelist class="dbus-property" generated="True" extra-ref="FirmwareDate"/>
 178
 179     <variablelist class="dbus-property" generated="True" extra-ref="MachineID"/>
 180
 181     <variablelist class="dbus-property" generated="True" extra-ref="BootID"/>
 182
 183     <variablelist class="dbus-property" generated="True" extra-ref="VSockCID"/>
 184
 185     <!--End of Autogenerated section-->
 186
 187     <para>Whenever the hostname or other metadata is changed via the daemon,
 188     <function>PropertyChanged</function> signals are sent out to subscribed clients. Changing a hostname
 189     using this interface is authenticated via
 190     <ulink url="https://www.freedesktop.org/software/polkit/docs/latest/">polkit</ulink>.</para>
 191   </refsect1>
 192
 193   <refsect1>
 194     <title>Semantics</title>
 195
 196     <para>The <varname>StaticHostname</varname> property exposes the "static" hostname configured in
 197     <filename>/etc/hostname</filename>. It is not always in sync with the current hostname as returned by the
 198     <citerefentry project="man-pages"><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 199     system call. If no static hostname is configured this property will be the empty string.</para>
 200
 201     <para>When <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry> or
 202     <citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 203     set the hostname, this static hostname <emphasis>has the highest priority</emphasis>.</para>
 204
 205     <para>The <varname>Hostname</varname> property exposes the actual hostname configured in the kernel via
 206     <citerefentry project="man-pages"><refentrytitle>sethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry>.
 207     It can be different from the static hostname. This property is never empty.</para>
 208
 209     <para>The <varname>PrettyHostname</varname> property exposes the <emphasis>pretty hostname</emphasis>
 210     which is a free-form UTF-8 hostname for presentation to the user. User interfaces should ensure that the
 211     pretty hostname and the static hostname stay in sync. E.g. when the former is <literal>Lennart’s
 212     Computer</literal> the latter should be <literal>lennarts-computer</literal>. If no pretty hostname is
 213     set this setting will be the empty string. Applications should then find a suitable fallback, such as the
 214     dynamic hostname.</para>
 215
 216     <para>The <varname>DefaultHostname</varname> property exposes the default hostname (configured through
 217     <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>, or a
 218     fallback set at compilation time).</para>
 219
 220     <para>The <varname>HostnameSource</varname> property exposes the origin of the currently configured
 221     hostname. One of <literal>static</literal> (set from <filename>/etc/hostname</filename>),
 222     <literal>transient</literal> (a non-permanent hostname from an external source),
 223     <literal>default</literal> (the value from <filename>os-release</filename> or the compiled-in
 224     fallback).</para>
 225
 226     <para>The <varname>IconName</varname> property exposes the <emphasis>icon name</emphasis> following the
 227     XDG icon naming spec. If not set, information such as the chassis type (see below) is used to find a
 228     suitable fallback icon name (i.e. <literal>computer-laptop</literal>
 229     vs. <literal>computer-desktop</literal> is picked based on the chassis information). If no such data is
 230     available, the empty string is returned. In that case an application should fall back to a replacement
 231     icon, for example <literal>computer</literal>. If this property is set to the empty string, the automatic
 232     fallback name selection is enabled again.</para>
 233
 234     <para>The <varname>Chassis</varname> property exposes a <emphasis>chassis type</emphasis>, one of the
 235     currently defined chassis types: <literal>desktop</literal>, <literal>laptop</literal>,
 236     <literal>server</literal>, <literal>tablet</literal>, <literal>handset</literal>, as well as the special
 237     chassis types <literal>vm</literal> and <literal>container</literal> for virtualized systems. Note that
 238     in most cases the chassis type will be determined automatically from DMI/SMBIOS/ACPI firmware
 239     information. Writing to this setting is hence useful only to override misdetected chassis types, or to
 240     configure the chassis type if it could not be auto-detected. Set this property to the empty string to
 241     reenable the automatic detection of the chassis type from firmware information.</para>
 242
 243     <para>Note that <filename>systemd-hostnamed</filename> starts only on request and terminates after a
 244     short idle period. This effectively means that <function>PropertyChanged</function> messages are not sent
 245     out for changes made directly on the files (as in: administrator edits the files with vi). This is
 246     the intended behavior: manual configuration changes should require manual reloading.</para>
 247
 248     <para>The transient (dynamic) hostname exposed by the <varname>Hostname</varname> property maps directly
 249     to the kernel hostname. This hostname should be assumed to be highly dynamic, and hence should be watched
 250     directly, without depending on <function>PropertyChanged</function> messages from
 251     <filename>systemd-hostnamed</filename>. To accomplish this, open
 252     <filename>/proc/sys/kernel/hostname</filename> and
 253     <citerefentry project="man-pages"><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 254     for <constant>SIGHUP</constant> which is triggered by the kernel every time the hostname changes. Again:
 255     this is special for the transient (dynamic) hostname, and does not apply to the configured (fixed)
 256     hostname.</para>
 257
 258     <para>Applications may read the hostname data directly if hostname change notifications
 259     are not necessary. Use
 260     <citerefentry project="man-pages"><refentrytitle>gethostname</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 261     <filename>/etc/hostname</filename> (possibly with per-distribution fallbacks), and
 262     <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 263     for that. For more information on these files and syscalls see the respective man pages.</para>
 264
 265     <para><varname>KernelName</varname>, <varname>KernelRelease</varname>, and
 266     <varname>KernelVersion</varname> expose the kernel name (e.g. <literal>Linux</literal>), release
 267     (e.g. <literal>5.0.0-11</literal>), and version (i.e. the build number, e.g. <literal>#11</literal>) as
 268     reported by <citerefentry project="man-pages"><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry>.
 269     <varname>OperatingSystemPrettyName</varname>, <varname>OperatingSystemCPEName</varname>, and
 270     <varname>HomeURL</varname> expose the <varname>PRETTY_NAME=</varname>, <varname>CPE_NAME=</varname> and
 271     <varname>HOME_URL=</varname> fields from
 272     <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
 273     purpose of those properties is to allow remote clients to access this information over D-Bus. Local
 274     clients can access the information directly.</para>
 275
 276     <para><varname>MachineID</varname> expose the 128bit machine ID, see
 277     <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
 278     details.</para>
 279
 280     <para><varname>BootID</varname> expose the 128bit boot ID, as per
 281     <filename>/proc/sys/kernel/random/boot_id</filename>.</para>
 282
 283     <para><varname>VSockCID</varname> exposes the system's local <constant>AF_VSOCK</constant> CID (Context
 284     Identifier, i.e. address) for the system, if one is available in the virtual machine environment. Set to
 285     <constant>UINT32_MAX</constant> otherwise. See <citerefentry project="man-pages"><refentrytitle>vsock</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
 286     details.</para>
 287
 288     <para><varname>OperatingSystemSupportEnd</varname> exposes when the OS' vendor support ends, if this
 289     information is known. It's an unsigned 64bit value, in µs since the UNIX epoch, UTC. If this information
 290     is not known carries the value 2^64-1, i.e. <constant>UINT64_MAX</constant>.</para>
 291
 292     <para><varname>HardwareVendor</varname> and <varname>HardwareModel</varname> expose information about the
 293     vendor of the hardware of the system. If no such information can be determined these properties are set
 294     to empty strings.</para>
 295
 296     <para><varname>FirmwareVersion</varname> and <varname>FirmwareVendor</varname> expose information about
 297     the system's firmware, i.e. a version string and a vendor name. If no such information can be determined
 298     these properties are set to empty strings.</para>
 299
 300     <para><varname>FirmwareDate</varname> exposes the firmware build date, if that information is known. It's
 301     an unsigned 64bit value, in µs since the UNIX epoch, UTC. If not known
 302     <constant>UNIT64_MAX</constant>.</para>
 303
 304     <refsect2>
 305       <title>Methods</title>
 306
 307       <para><function>SetHostname()</function> sets the transient (dynamic) hostname, which is used if no
 308       static hostname is set. This value must be an internet-style hostname, 7-bit lowercase ASCII, no
 309       special chars/spaces. An empty string will unset the transient hostname.</para>
 310
 311       <para><function>SetStaticHostname()</function> sets the static hostname which is exposed by the
 312       <varname>StaticHostname</varname> property. When called with an empty argument, the static
 313       configuration in <filename>/etc/hostname</filename> is removed. Since the static hostname has the
 314       highest priority, calling this function usually affects also the <varname>Hostname</varname> property
 315       and the effective hostname configured in the kernel.</para>
 316
 317       <para><function>SetPrettyHostname()</function> sets the pretty hostname which is exposed by the
 318       <varname>PrettyHostname</varname> property.</para>
 319
 320       <para><function>SetIconName()</function>, <function>SetChassis()</function>,
 321       <function>SetDeployment()</function>, and <function>SetLocation()</function> set the properties
 322       <varname>IconName</varname> (the name of the icon representing for the machine),
 323       <varname>Chassis</varname> (the machine form factor), <varname>Deployment</varname> (the system
 324       deployment environment), and <varname>Location</varname> (physical system location), respectively.
 325       </para>
 326
 327       <para><varname>PrettyHostname</varname>, <varname>IconName</varname>, <varname>Chassis</varname>,
 328       <varname>Deployment</varname>, and <varname>Location</varname> are stored in
 329       <filename>/etc/machine-info</filename>. See
 330       <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
 331       the semantics of those settings.</para>
 332
 333       <para><function>GetProductUUID()</function> returns the "product UUID" as exposed by the kernel based
 334       on DMI information in <filename>/sys/class/dmi/id/product_uuid</filename>. Reading the file directly
 335       requires root privileges, and this method allows access to unprivileged clients through the polkit
 336       framework.</para>
 337
 338       <para><function>GetHardwareSerial()</function> returns the "hardware serial" as exposed by the kernel
 339       based on DMI information. Reading the file directly requires root privileges, and this method allows
 340       access to unprivileged clients through the polkit framework.</para>
 341
 342       <para><function>Describe()</function> returns a JSON representation of all properties in one.</para>
 343     </refsect2>
 344
 345     <refsect2>
 346       <title>Security</title>
 347
 348       <para>The <varname>interactive</varname> boolean parameters can be used to control whether polkit
 349       should interactively ask the user for authentication credentials if required.</para>
 350
 351       <para>The polkit action for <function>SetHostname()</function> is
 352       <interfacename>org.freedesktop.hostname1.set-hostname</interfacename>. For
 353       <function>SetStaticHostname()</function> and <function>SetPrettyHostname()</function> it is
 354       <interfacename>org.freedesktop.hostname1.set-static-hostname</interfacename>. For
 355       <function>SetIconName()</function>, <function>SetChassis()</function>, <function>SetDeployment()</function>
 356       and <function>SetLocation()</function> it is
 357       <interfacename>org.freedesktop.hostname1.set-machine-info</interfacename>.</para>
 358     </refsect2>
 359   </refsect1>
 360
 361   <refsect1>
 362     <title>Recommendations</title>
 363
 364     <para>Here are three examples that show how the pretty hostname and the icon name should be used:
 365     <itemizedlist>
 366       <listitem><para>When registering DNS-SD services: use the pretty hostname in the service name, and pass
 367       the icon name in the TXT data, if there is an icon name. Browsing clients can then show the server icon
 368       on each service. This is especially useful for WebDAV applications or UPnP media sharing.
 369       </para></listitem>
 370
 371       <listitem><para>Set the bluetooth name to the pretty hostname.</para></listitem>
 372
 373       <listitem><para>When your file browser has a "Computer" icon, replace the name with the pretty hostname
 374       if set, and the icon with the icon name, if it is set.</para></listitem>
 375     </itemizedlist></para>
 376
 377     <para>To properly handle name lookups with changing local hostnames without having to edit
 378     <filename>/etc/hosts</filename>, we recommend using <filename>systemd-hostnamed</filename> in combination
 379     with <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 380     </para>
 381
 382     <para>Here are some recommendations to follow when generating a static (internet) hostname from a pretty
 383     name:
 384     <itemizedlist>
 385       <listitem><para>Generate a single DNS label only, not an FQDN. That means no dots allowed. Strip them,
 386       or replace them with <literal>-</literal>.</para></listitem>
 387
 388       <listitem><para>It's probably safer to not use any non-ASCII chars, even if DNS allows this in some way
 389       these days. In fact, restrict your charset to <literal>a-zA-Z0-9</literal> and <literal>-</literal>.
 390       Strip other chars, or try to replace them in some smart way with chars from this set, for example
 391       <literal>ä</literal> → <literal>ae</literal>, and use <literal>-</literal> as the replacement for all
 392       punctuation characters and whitespace.</para></listitem>
 393
 394       <listitem><para>Try to avoid creating repeated <literal>-</literal>, as well as <literal>-</literal> as
 395       the first or last char.</para></listitem>
 396
 397       <listitem><para>Limit the hostname to 63 chars, which is the length of a DNS label.</para></listitem>
 398
 399       <listitem><para>If after stripping special chars the empty string is the result, you can pass this
 400       as-is to <filename>systemd-hostnamed</filename> in which case it will automatically use a suitable
 401       fallback.</para></listitem>
 402
 403       <listitem><para>Uppercase characters should be replaced with their lowercase equivalents.
 404       </para></listitem>
 405     </itemizedlist></para>
 406
 407     <para>Note that while <filename>systemd-hostnamed</filename> applies some checks to the hostname you pass
 408     they are much looser than the recommendations above. For example, <filename>systemd-hostnamed</filename>
 409     will also accept <literal>_</literal> in the hostname, but we recommend not using this to avoid clashes
 410     with DNS-SD service types. Also <filename>systemd-hostnamed</filename> allows longer hostnames, but
 411     because of the DNS label limitations, we recommend not making use of this.</para>
 412
 413     <para>Here are a couple of example conversions:
 414     <itemizedlist>
 415       <listitem><para><literal>Lennart's PC</literal> → <literal>lennarts-pc</literal></para></listitem>
 416       <listitem><para><literal>Müllers Computer</literal> → <literal>muellers-computer</literal></para></listitem>
 417       <listitem><para><literal>Voran!</literal> → <literal>voran</literal></para></listitem>
 418       <listitem><para><literal>Es war einmal ein Männlein</literal> → <literal>es-war-einmal-ein-maennlein</literal></para></listitem>
 419       <listitem><para><literal>Jawoll. Ist doch wahr!</literal> → <literal>jawoll-ist-doch-wahr</literal></para></listitem>
 420       <listitem><para><literal>レナート</literal> → <literal>localhost</literal></para></listitem>
 421       <listitem><para><literal>...zack!!! zack!...</literal> → <literal>zack-zack</literal></para></listitem>
 422     </itemizedlist></para>
 423
 424     <para>Of course, an already valid internet hostname label you enter and pass through this
 425     conversion should stay unmodified, so that users have direct control of it, if they want — by simply
 426     ignoring the fact that the pretty hostname is pretty and just edit it as if it was the normal internet
 427     name.</para>
 428   </refsect1>
 429
 430   <xi:include href="org.freedesktop.locale1.xml" xpointer="versioning"/>
 431
 432   <refsect1>
 433     <title>Examples</title>
 434
 435     <example>
 436       <title>Introspect <interfacename>org.freedesktop.hostname1</interfacename> on the bus</title>
 437
 438       <programlisting>$ gdbus introspect --system \
 439   --dest org.freedesktop.hostname1 \
 440   --object-path /org/freedesktop/hostname1
 441       </programlisting>
 442     </example>
 443   </refsect1>
 444
 445   <refsect1>
 446     <title>See Also</title>
 447
 448     <para>David Zeuthen's original Fedora
 449     <ulink url="https://fedoraproject.org/wiki/Features/BetterHostname">Feature page about xdg-hostname</ulink></para>
 450   </refsect1>
 451
 452   <refsect1>
 453     <title>History</title>
 454     <refsect2>
 455       <title>The D-Bus API</title>
 456       <para><varname>FirmwareVersion</varname> and
 457       <function>GetHardwareSerial()</function> were added in version 251.</para>
 458       <para><varname>OperatingSystemSupportEnd</varname>,
 459       <varname>FirmwareVendor</varname>, and
 460       <varname>FirmwareDate</varname> were added in version 253.</para>
 461       <para><varname>MachineID</varname>, <varname>BootID</varname> and
 462       <varname>VSockCID</varname> were added in version 256.</para>
 463     </refsect2>
 464   </refsect1>
 465 </refentry>