man/org.freedesktop.timedate1.xml

   1 <?xml version='1.0'?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" >
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="org.freedesktop.timedate1" conditional='ENABLE_TIMEDATED'
   7     xmlns:xi="http://www.w3.org/2001/XInclude">
   8   <refentryinfo>
   9     <title>org.freedesktop.timedate1</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>org.freedesktop.timedate1</refentrytitle>
  15     <manvolnum>5</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>org.freedesktop.timedate1</refname>
  20     <refpurpose>The D-Bus interface of systemd-timedated</refpurpose>
  21   </refnamediv>
  22
  23   <refsect1>
  24     <title>Introduction</title>
  25
  26     <para>
  27     <citerefentry><refentrytitle>systemd-timedated.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  28     is a system service that can be used to control the system time and related settings. This page
  29     describes the D-Bus interface.</para>
  30   </refsect1>
  31
  32   <refsect1>
  33     <title>The D-Bus API</title>
  34
  35     <para>The service exposes the following interfaces on the bus:</para>
  36
  37     <programlisting executable="systemd-timedated" node="/org/freedesktop/timedate1" interface="org.freedesktop.timedate1">
  38 node /org/freedesktop/timedate1 {
  39   interface org.freedesktop.timedate1 {
  40     methods:
  41       SetTime(in  x usec_utc,
  42               in  b relative,
  43               in  b interactive);
  44       SetTimezone(in  s timezone,
  45                   in  b interactive);
  46       SetLocalRTC(in  b local_rtc,
  47                   in  b fix_system,
  48                   in  b interactive);
  49       SetNTP(in  b use_ntp,
  50              in  b interactive);
  51       ListTimezones(out as timezones);
  52     properties:
  53       readonly s Timezone = '...';
  54       readonly b LocalRTC = ...;
  55       @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
  56       readonly b CanNTP = ...;
  57       readonly b NTP = ...;
  58       @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
  59       readonly b NTPSynchronized = ...;
  60       @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
  61       readonly t TimeUSec = ...;
  62       @org.freedesktop.DBus.Property.EmitsChangedSignal("false")
  63       readonly t RTCTimeUSec = ...;
  64   };
  65   interface org.freedesktop.DBus.Peer { ... };
  66   interface org.freedesktop.DBus.Introspectable { ... };
  67   interface org.freedesktop.DBus.Properties { ... };
  68 };
  69     </programlisting>
  70
  71     <!--Autogenerated cross-references for systemd.directives, do not edit-->
  72
  73     <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.timedate1"/>
  74
  75     <variablelist class="dbus-interface" generated="True" extra-ref="org.freedesktop.timedate1"/>
  76
  77     <variablelist class="dbus-method" generated="True" extra-ref="SetTime()"/>
  78
  79     <variablelist class="dbus-method" generated="True" extra-ref="SetTimezone()"/>
  80
  81     <variablelist class="dbus-method" generated="True" extra-ref="SetLocalRTC()"/>
  82
  83     <variablelist class="dbus-method" generated="True" extra-ref="SetNTP()"/>
  84
  85     <variablelist class="dbus-method" generated="True" extra-ref="ListTimezones()"/>
  86
  87     <variablelist class="dbus-property" generated="True" extra-ref="Timezone"/>
  88
  89     <variablelist class="dbus-property" generated="True" extra-ref="LocalRTC"/>
  90
  91     <variablelist class="dbus-property" generated="True" extra-ref="CanNTP"/>
  92
  93     <variablelist class="dbus-property" generated="True" extra-ref="NTP"/>
  94
  95     <variablelist class="dbus-property" generated="True" extra-ref="NTPSynchronized"/>
  96
  97     <variablelist class="dbus-property" generated="True" extra-ref="TimeUSec"/>
  98
  99     <variablelist class="dbus-property" generated="True" extra-ref="RTCTimeUSec"/>
 100
 101     <!--End of Autogenerated section-->
 102
 103     <refsect2>
 104       <title>Methods</title>
 105
 106       <para>Use <function>SetTime()</function> to change the system clock. Pass a value of microseconds since
 107       the UNIX epoch (1 Jan 1970 UTC). If <varname>relative</varname> is true, the passed usec value will be
 108       added to the current system time. If it is false, the current system time will be set to the passed usec
 109       value. If the system time is set with this method, the RTC will be updated as well.</para>
 110
 111       <para>Use <function>SetTimezone()</function> to set the system timezone. Pass a value like
 112       <literal>Europe/Berlin</literal> to set the timezone. Valid timezones are listed in
 113       <filename>/usr/share/zoneinfo/zone.tab</filename>. If the RTC is configured to be maintained in local
 114       time, it will be updated accordingly.</para>
 115
 116       <para>Use <function>SetLocalRTC()</function> to control whether the RTC is in local time or UTC. It is
 117       strongly recommended to maintain the RTC in UTC. However, some OSes (Windows) maintain the RTC in local
 118       time, which might make it necessary to enable this feature. Note that this might create various problems as
 119       daylight changes could be missed. If <varname>fix_system</varname> is <literal>true</literal>,
 120       the time from the RTC is read again and the system clock is adjusted according to the new setting. If
 121       <varname>fix_system</varname> is <literal>false</literal>, the system time is written to the RTC
 122       taking the new setting into account. Use <varname>fix_system=true</varname> in installers and livecds
 123       where the RTC is probably more reliable than the system time. Use <varname>fix_system=false</varname>
 124       in configuration UIs that are run during normal operation and where the system clock is probably more
 125       reliable than the RTC.</para>
 126
 127       <para>Use <function>SetNTP()</function> to control whether the system clock is synchronized with the
 128       network using <filename>systemd-timesyncd</filename>. This will enable and start or disable and stop
 129       the chosen time synchronization service.</para>
 130
 131       <para><function>ListTimezones()</function> returns a list of time zones known on the local system as an
 132       array of names (<literal>["Africa/Abidjan", "Africa/Accra", ..., "UTC"]</literal>).</para>
 133     </refsect2>
 134
 135     <refsect2>
 136       <title>Properties</title>
 137
 138       <para><varname>Timezone</varname> shows the currently configured time zone.
 139       <varname>LocalRTC</varname> shows whether the RTC is configured to use UTC (false), or the local time
 140       zone (true). <varname>CanNTP</varname> shows whether a service to perform time synchronization over the
 141       network is available, and <varname>NTP</varname> shows whether such a service is enabled.</para>
 142
 143       <para><varname>NTPSynchronized</varname> shows whether the kernel reports the time as synchronized
 144       (c.f.
 145       <citerefentry project="man-pages"><refentrytitle>adjtimex</refentrytitle><manvolnum>3</manvolnum></citerefentry>).
 146       <varname>TimeUSec</varname> and <varname>RTCTimeUSec</varname> show the current time on the system and
 147       in the RTC. The purpose of those three properties is to allow remote clients to access this information
 148       over D-Bus. Local clients can access the information directly.</para>
 149
 150       <para>Whenever the <varname>Timezone</varname> and <varname>LocalRTC</varname> settings are changed via
 151       the daemon, <function>PropertyChanged</function> signals are sent out to which clients can subscribe.
 152       </para>
 153
 154       <para>Note that this service will not inform you about system time changes. Use
 155       <citerefentry project="man-pages"><refentrytitle>timerfd</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 156       with <constant>CLOCK_REALTIME</constant> and <constant>TFD_TIMER_CANCEL_ON_SET</constant> for that.
 157       </para>
 158     </refsect2>
 159
 160     <refsect2>
 161       <title>Security</title>
 162
 163       <para>The <varname>interactive</varname> boolean parameters can be used to control whether
 164       <ulink url="https://www.freedesktop.org/software/polkit/docs/latest/">polkit</ulink>
 165       should interactively ask the user for authentication credentials if required.</para>
 166
 167       <para>The polkit action for <function>SetTimezone()</function> is
 168       <interfacename>org.freedesktop.timedate1.set-timezone</interfacename>. For
 169       <function>SetLocalRTC()</function> it is
 170       <interfacename>org.freedesktop.timedate1.set-local-rtc</interfacename>, for
 171       <function>SetTime()</function> it is <interfacename>org.freedesktop.timedate1.set-time</interfacename>
 172       and for <function>SetNTP()</function> it is
 173       <interfacename>org.freedesktop.timedate1.set-ntp</interfacename>.
 174       <function>ListTimezones()</function> does not require any privileges.
 175       </para>
 176     </refsect2>
 177   </refsect1>
 178
 179   <refsect1>
 180     <title>Examples</title>
 181
 182     <example>
 183       <title>Introspect <interfacename>org.freedesktop.timedate1</interfacename> on the bus</title>
 184
 185       <programlisting>
 186 $ gdbus introspect --system \
 187   --dest org.freedesktop.timedate1 \
 188   --object-path /org/freedesktop/timedate1
 189       </programlisting>
 190     </example>
 191   </refsect1>
 192
 193   <refsect1>
 194     <title>Versioning</title>
 195
 196     <para>These D-Bus interfaces follow <ulink url="http://0pointer.de/blog/projects/versioning-dbus.html">
 197     the usual interface versioning guidelines</ulink>.</para>
 198   </refsect1>
 199
 200   <refsect1>
 201     <title>See also</title>
 202
 203       <para><ulink url="https://lists.freedesktop.org/archives/systemd-devel/2011-May/002526.html">More information on how the system clock and RTC interact</ulink></para>
 204   </refsect1>
 205 </refentry>