<para>
<citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
- is a system service that can be used to control the host name and related machine meta data from user
+ is a system service that can be used to control the hostname and related machine metadata from user
programs. This page describes the hostname semantics and the D-Bus interface.</para>
</refsect1>
<para>The service exposes the following interfaces on the bus:</para>
- <programlisting>
-$ gdbus introspect --system \
- --dest org.freedesktop.hostname1 \
- --object-path /org/freedesktop/hostname1
-
+ <programlisting executable="systemd-hostnamed" node="/org/freedesktop/hostname1" interface="org.freedesktop.hostname1">
node /org/freedesktop/hostname1 {
interface org.freedesktop.hostname1 {
methods:
- SetHostname(in s name,
- in b user_interaction);
- SetStaticHostname(in s name,
- in b user_interaction);
- SetPrettyHostname(in s name,
- in b user_interaction);
- SetIconName(in s name,
- in b user_interaction);
- SetChassis(in s name,
- in b user_interaction);
- signals:
+ SetHostname(in s hostname,
+ in b interactive);
+ SetStaticHostname(in s hostname,
+ in b interactive);
+ SetPrettyHostname(in s hostname,
+ in b interactive);
+ SetIconName(in s icon,
+ in b interactive);
+ SetChassis(in s chassis,
+ in b interactive);
+ SetDeployment(in s deployment,
+ in b interactive);
+ SetLocation(in s location,
+ in b interactive);
+ GetProductUUID(in b interactive,
+ out ay uuid);
properties:
- readonly s Hostname = 'dhcp-192-168-47-11';
- readonly s StaticHostname = 'lennarts-computer';
- readonly s PrettyHostname = 'Lennart’s Computer';
- readonly s IconName = 'computer-laptop';
- readonly s Chassis = 'laptop';
- };
- interface org.freedesktop.DBus.Properties {
- };
- interface org.freedesktop.DBus.Introspectable {
- };
- interface org.freedesktop.DBus.Peer {
+ readonly s Hostname = '...';
+ readonly s StaticHostname = '...';
+ readonly s PrettyHostname = '...';
+ readonly s IconName = '...';
+ readonly s Chassis = '...';
+ readonly s Deployment = '...';
+ readonly s Location = '...';
+ @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+ readonly s KernelName = '...';
+ @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+ readonly s KernelRelease = '...';
+ @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+ readonly s KernelVersion = '...';
+ @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+ readonly s OperatingSystemPrettyName = '...';
+ @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+ readonly s OperatingSystemCPEName = '...';
+ @org.freedesktop.DBus.Property.EmitsChangedSignal("const")
+ readonly s HomeURL = '...';
};
+ interface org.freedesktop.DBus.Peer { ... };
+ interface org.freedesktop.DBus.Introspectable { ... };
+ interface org.freedesktop.DBus.Properties { ... };
};
</programlisting>
- <para>Whenever the hostname or other meta data is changed via the daemon,
+ <!--Autogenerated cross-references for systemd.directives, do not edit-->
+
+ <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.hostname1"/>
+
+ <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.hostname1"/>
+
+ <variablelist class="dbus-method" generated="True" extra-ref="SetHostname()"/>
+
+ <variablelist class="dbus-method" generated="True" extra-ref="SetStaticHostname()"/>
+
+ <variablelist class="dbus-method" generated="True" extra-ref="SetPrettyHostname()"/>
+
+ <variablelist class="dbus-method" generated="True" extra-ref="SetIconName()"/>
+
+ <variablelist class="dbus-method" generated="True" extra-ref="SetChassis()"/>
+
+ <variablelist class="dbus-method" generated="True" extra-ref="SetDeployment()"/>
+
+ <variablelist class="dbus-method" generated="True" extra-ref="SetLocation()"/>
+
+ <variablelist class="dbus-method" generated="True" extra-ref="GetProductUUID()"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="Hostname"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="StaticHostname"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="PrettyHostname"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="IconName"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="Chassis"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="Deployment"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="Location"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="KernelName"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="KernelRelease"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="KernelVersion"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="OperatingSystemPrettyName"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="OperatingSystemCPEName"/>
+
+ <variablelist class="dbus-property" generated="True" extra-ref="HomeURL"/>
+
+ <!--End of Autogenerated section-->
+
+ <para>Whenever the hostname or other metadata is changed via the daemon,
<function>PropertyChanged</function> signals are sent out to subscribed clients. Changing a hostname
- using this interface is authenticated via PolicyKit.</para>
+ using this interface is authenticated via
+ <ulink url="https://www.freedesktop.org/software/polkit/docs/latest/">polkit</ulink>.</para>
</refsect1>
<refsect1>
<title>Semantics</title>
- <para>The <emphasis>static (configured) host name</emphasis> is the one configured in
+ <para>The <emphasis>static (configured) hostname</emphasis> is the one configured in
<filename>/etc/hostname</filename>. It is chosen by the local user. It is not always in sync with the
current hostname as returned by the
- <citerefentry project='man-pages'><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- system call. If no host name is configured this property will be the empty string. Setting this property
- to the empty string will remove <filename>/etc/hostname</filename>. This hostname should be an
+ <citerefentry project="man-pages"><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ system call. If no hostname is configured this property will be the empty string. Setting this property
+ to the empty string will remove <filename>/etc/hostname</filename>. This property should be an
internet-style hostname, 7-bit lowercase ASCII, no special chars/spaces.</para>
- <para>The <emphasis>transient (dynamic) host name</emphasis> is the one configured via the kernel's
- <citerefentry project='man-pages'><refentrytitle>sethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
- It can be different from the static hostname in case DHCP or mDNS have been configured to change the name
+ <para>The <emphasis>transient (dynamic) hostname</emphasis> is the one configured via the kernel's
+ <citerefentry project="man-pages"><refentrytitle>sethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ It can be different from the static hostname if DHCP or mDNS have been configured to change the name
based on network information. <!-- FIXME: it's not DHCP that configures this... -->
This property is never empty. If no hostname is set this will default to
<literal>&FALLBACK_HOSTNAME;</literal> (configurable at compilation time). Setting this property to the
- empty string will reset the dynamic hostname to the static host name. If no static host name is
- configured the dynamic host name will be reset to <literal>&FALLBACK_HOSTNAME;</literal>. This hostname
+ empty string will reset the dynamic hostname to the static hostname. If no static hostname is
+ configured the dynamic hostname will be reset to <literal>&FALLBACK_HOSTNAME;</literal>. This property
should be an internet-style hostname, 7-bit lowercase ASCII, no special chars/spaces.</para>
- <para>The <emphasis>pretty host name</emphasis> is a free-form UTF-8 host name for presentation to the
+ <para>The <emphasis>pretty hostname</emphasis> is a free-form UTF-8 hostname for presentation to the
user. User interfaces should ensure that the pretty hostname and the static hostname stay in sync.
I.e. when the former is <literal>Lennart’s Computer</literal> the latter should be
- <literal>lennarts-computer</literal>. If no pretty host name is set this setting will be the empty
+ <literal>lennarts-computer</literal>. If no pretty hostname is set this setting will be the empty
string. Applications should then find a suitable fallback, such as the dynamic hostname.</para>
<para>The <emphasis>icon name</emphasis> is a name following the XDG icon naming spec. If not set,
information such as the chassis type (see below) is used to find a suitable fallback icon name
(i.e. <literal>computer-laptop</literal> vs. <literal>computer-desktop</literal> is picked based on the
- chassis information). If no such data is available, returns the empty string. In that case an application
+ chassis information). If no such data is available, the empty string is returned. In that case an application
should fall back to a replacement icon, for example <literal>computer</literal>. If this property is set
- to the empty string, this automatic fallback name selection is enabled again.</para>
+ to the empty string, the automatic fallback name selection is enabled again.</para>
- <para>The <emphasis>chassis type</emphasis> should be one of the following that are currently defined:
+ <para>The <emphasis>chassis type</emphasis> should be one of the currently defined chassis types:
<literal>desktop</literal>, <literal>laptop</literal>, <literal>server</literal>,
<literal>tablet</literal>, <literal>handset</literal>, as well as the special chassis types
<literal>vm</literal> and <literal>container</literal> for virtualized systems. Note that in most cases
the chassis type will be determined automatically from DMI/SMBIOS/ACPI firmware information. Writing to
- this setting is hence useful only to override misdetected chassis types, or configure a chassis type if
- none could be auto-detected. Set this property to the empty string to reenable the automatic detection of
+ this setting is hence useful only to override misdetected chassis types, or to configure the chassis type if
+ it could not be auto-detected. Set this property to the empty string to reenable the automatic detection of
the chassis type from firmware information.</para>
- <para>A client which wants to change the local host name for DHCP/mDNS should invoke
- <code>SetHostname("newname", false)</code> as soon as the name is available and afterwards reset it via
- <code>SetHostname("")</code>.</para>
-
<para>Note that <filename>systemd-hostnamed</filename> starts only on request and terminates after a
short idle period. This effectively means that <function>PropertyChanged</function> messages are not sent
out for changes made directly on the files (as in: administrator edits the files with vi). This is
- actually intended behavior: manual configuration changes should require manual reloading of them.</para>
+ the intended behavior: manual configuration changes should require manual reloading.</para>
- <para>The transient (dynamic) hostname directly maps to the kernel hostname. This hostname should be
- assumed to be highly dynamic, and hence should be watched directly, without involving
- <function>PropertyChanged</function> messages from <filename>systemd-hostnamed</filename>. For that, open
- <filename>/proc/sys/kernel/hostname</filename> and
- <citerefentry project='man-pages'><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ <para>The transient (dynamic) hostname maps directly to the kernel hostname. This hostname should be
+ assumed to be highly dynamic, and hence should be watched directly, without depending on
+ <function>PropertyChanged</function> messages from <filename>systemd-hostnamed</filename>. To accomplish
+ this, open <filename>/proc/sys/kernel/hostname</filename> and
+ <citerefentry project="man-pages"><refentrytitle>poll</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for <constant>SIGHUP</constant> which is triggered by the kernel every time the hostname changes. Again:
this is special for the transient (dynamic) hostname, and does not apply to the configured (fixed)
hostname.</para>
- <para>Applications may bypass the daemon to read the hostname data if notifications of host name changes
+ <para>Applications may read the hostname data directly if hostname change notifications
are not necessary. Use
- <citerefentry project='man-pages'><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry project="man-pages"><refentrytitle>gethostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<filename>/etc/hostname</filename> (possibly with per-distribution fallbacks), and
<citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for that. For more information on these files and syscalls see the respective man pages.</para>
- <para>The user_interaction boolean parameters can be used to control whether PolicyKit should
- interactively ask the user for authentication credentials if it needs to.</para>
+ <refsect2>
+ <title>Methods and Properties</title>
+
+ <para><function>SetHostname()</function> sets the transient (dynamic) hostname which is exposed by the
+ <varname>Hostname</varname> property. If empty, the transient hostname is set to the static hostname.
+ </para>
+
+ <para><function>SetStaticHostname()</function> sets the static hostname which is exposed by the
+ <varname>StaticHostname</varname> property. If empty, the built-in default of
+ <literal>&FALLBACK_HOSTNAME;</literal> is used.</para>
+
+ <para><function>SetPrettyHostname()</function> sets the pretty hostname which is exposed by the
+ <varname>PrettyHostname</varname> property.</para>
+
+ <para><function>SetIconName()</function>, <function>SetChassis()</function>,
+ <function>SetDeployment()</function>, and <function>SetLocation()</function> set the properties
+ <varname>IconName</varname> (the name of the icon representing for the machine),
+ <varname>Chassis</varname> (the machine form factor), <varname>Deployment</varname> (the system
+ deployment environment), and <varname>Location</varname> (physical system location), respectively.
+ </para>
+
+ <para><varname>PrettyHostname</varname>, <varname>IconName</varname>, <varname>Chassis</varname>,
+ <varname>Deployment</varname>, and <varname>Location</varname> are stored in
+ <filename>/etc/machine-info</filename>. See
+ <citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
+ the semantics of those settings.</para>
+
+ <para><function>GetProductUUID()</function> returns the "product uuid" as exposed by the kernel based
+ on DMI information in <filename>/sys/class/dmi/id/product_uuid</filename>. Reading the file directly
+ requires root privileges, and this method allows access to unprivileged clients through the polkit
+ framework.</para>
+
+ <para><varname>KernelName</varname>, <varname>KernelRelease</varname>, and
+ <varname>KernelVersion</varname> expose the kernel name (e.g. <literal>Linux</literal>), release
+ (e.g. <literal>5.0.0-11</literal>), and version (i.e. the build number, e.g. <literal>#11</literal>) as
+ reported by
+ <citerefentry project="man-pages"><refentrytitle>uname</refentrytitle><manvolnum>2</manvolnum></citerefentry>.
+ <varname>OperatingSystemPrettyName</varname>, <varname>OperatingSystemCPEName</varname>, and
+ <varname>HomeURL</varname> expose the <varname>PRETTY_NAME=</varname>, <varname>CPE_NAME=</varname> and
+ <varname>HOME_URL=</varname> fields from
+ <citerefentry><refentrytitle>os-release</refentrytitle><manvolnum>5</manvolnum></citerefentry>. The
+ purpose of those properties is to allow remote clients to access this information over D-Bus. Local
+ clients can access the information directly.</para>
+ </refsect2>
+
+ <refsect2>
+ <title>Security</title>
+
+ <para>The <varname>interactive</varname> boolean parameters can be used to control whether polkit
+ should interactively ask the user for authentication credentials if required.</para>
+
+ <para>The polkit action for <function>SetHostname()</function> is
+ <interfacename>org.freedesktop.hostname1.set-hostname</interfacename>. For
+ <function>SetStaticHostname()</function> and <function>SetPrettyHostname()</function> it is
+ <interfacename>org.freedesktop.hostname1.set-static-hostname</interfacename>. For
+ <function>SetIconName()</function> and <function>SetChassis()</function> it is
+ <interfacename>org.freedesktop.hostname1.set-machine-info</interfacename>.</para>
+ </refsect2>
+ </refsect1>
- <para>The PolicyKit action for <function>SetHostname()</function> is
- <interfacename>org.freedesktop.hostname1.set-hostname</interfacename>. For
- <function>SetStaticHostname()</function> and <function>SetPrettyHostname()</function> it is
- <interfacename>org.freedesktop.hostname1.set-static-hostname</interfacename>. For
- <function>SetIconName()</function> and <function>SetChassis()</function> it is
- <interfacename>org.freedesktop.hostname1.set-machine-info</interfacename>.</para>
+ <refsect1>
+ <title>Recommendations</title>
- <para>Here are three examples how the pretty hostname and the icon name should be used:
+ <para>Here are three examples that show how the pretty hostname and the icon name should be used:
<itemizedlist>
- <listitem><para>When registering DNS-SD services: use the pretty host name in the service name, and
- pass the icon name in the TXT data, if there is an icon name. Browsing clients can then show the server
- icon on each service. Especially useful for WebDAV stuff. Similar for UPnP media
- sharing.</para></listitem>
+ <listitem><para>When registering DNS-SD services: use the pretty hostname in the service name, and pass
+ the icon name in the TXT data, if there is an icon name. Browsing clients can then show the server icon
+ on each service. This is especially useful for WebDAV applications or UPnP media sharing.
+ </para></listitem>
- <listitem><para>Set the bluetooth name to the pretty host name.</para></listitem>
+ <listitem><para>Set the bluetooth name to the pretty hostname.</para></listitem>
- <listitem><para>When your file browser has a "Computer" icon, replace the name with the pretty hostname if set, and the icon with the icon name, if it is set.</para></listitem>
+ <listitem><para>When your file browser has a "Computer" icon, replace the name with the pretty hostname
+ if set, and the icon with the icon name, if it is set.</para></listitem>
</itemizedlist></para>
<para>To properly handle name lookups with changing local hostnames without having to edit
- <filename>/etc/hosts</filename> for them, we recommend using <filename>systemd-hostnamed</filename> in
- combination with <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
+ <filename>/etc/hosts</filename>, we recommend using <filename>systemd-hostnamed</filename> in combination
+ with <citerefentry><refentrytitle>nss-myhostname</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
+ <para>A client that wants to change the local hostname for DHCP/mDNS should invoke
+ <code>SetHostname("newname", false)</code> as soon as the name is available and afterwards reset it via
+ <code>SetHostname("")</code>.</para>
+
<para>Here are some recommendations to follow when generating a static (internet) hostname from a pretty
name:
<itemizedlist>
<listitem><para>Generate a single DNS label only, not an FQDN. That means no dots allowed. Strip them,
- or replace them by <literal>-</literal>.</para></listitem>
+ or replace them with <literal>-</literal>.</para></listitem>
- <listitem><para>It's probably safer not to use any non-ASCII chars, even if DNS allows this in some way
+ <listitem><para>It's probably safer to not use any non-ASCII chars, even if DNS allows this in some way
these days. In fact, restrict your charset to <literal>a-zA-Z0-9</literal> and <literal>-</literal>.
Strip other chars, or try to replace them in some smart way with chars from this set, for example
- <literal>ä</literal> → <literal>ae</literal>, and use <literal>-</literal> as replacement for all kinds
- of punctuation chars or spaces.</para></listitem>
+ <literal>ä</literal> → <literal>ae</literal>, and use <literal>-</literal> as the replacement for all
+ punctuation characters and whitespace.</para></listitem>
<listitem><para>Try to avoid creating repeated <literal>-</literal>, as well as <literal>-</literal> as
the first or last char.</para></listitem>
<listitem><para>Limit the hostname to 63 chars, which is the length of a DNS label.</para></listitem>
<listitem><para>If after stripping special chars the empty string is the result, you can pass this
- as-is to <filename>systemd-hostnamed</filename> in which case it will automatically make
- <literal>&FALLBACK_HOSTNAME;</literal> out of this.</para></listitem>
+ as-is to <filename>systemd-hostnamed</filename> in which case it will automatically use
+ <literal>&FALLBACK_HOSTNAME;</literal>.</para></listitem>
- <listitem><para>It probably is a good idea to replace uppercase by lowercase chars.</para></listitem>
+ <listitem><para>Uppercase charaacters should be replaced with their lowercase equivalents.
+ </para></listitem>
</itemizedlist></para>
<para>Note that while <filename>systemd-hostnamed</filename> applies some checks to the hostname you pass
they are much looser than the recommendations above. For example, <filename>systemd-hostnamed</filename>
- will also accept <literal>_</literal> in the hostname, but I'd recommend not using this to avoid clashes
+ will also accept <literal>_</literal> in the hostname, but we recommend not using this to avoid clashes
with DNS-SD service types. Also <filename>systemd-hostnamed</filename> allows longer hostnames, but
- because of the DNS label limitations, I'd recommend not making use of this.</para>
+ because of the DNS label limitations, we recommend not making use of this.</para>
<para>Here are a couple of example conversions:
<itemizedlist>
<listitem><para><literal>...zack!!! zack!...</literal> → <literal>zack-zack</literal></para></listitem>
</itemizedlist></para>
- <para>Oh, and of course, an already valid internet hostname label you enter and pass through this
- conversion should stay unmodified, so that users have direct control of it, if they want -- by simply
+ <para>Of course, an already valid internet hostname label you enter and pass through this
+ conversion should stay unmodified, so that users have direct control of it, if they want — by simply
ignoring the fact that the pretty hostname is pretty and just edit it as if it was the normal internet
name.</para>
</refsect1>
the usual interface versioning guidelines</ulink>.</para>
</refsect1>
+ <refsect1>
+ <title>Examples</title>
+
+ <example>
+ <title>Introspect <interfacename>org.freedesktop.hostname1</interfacename> on the bus</title>
+
+ <programlisting>$ gdbus introspect --system \
+ --dest org.freedesktop.hostname1 \
+ --object-path /org/freedesktop/hostname1
+ </programlisting>
+ </example>
+ </refsect1>
+
<refsect1>
<title>See also</title>
projects / thirdparty / systemd.git / blobdiff