man/busctl.xml

   1 <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   SPDX-License-Identifier: LGPL-2.1+
   7
   8   Copyright 2014 Zbigniew Jędrzejewski-Szmek
   9 -->
  10
  11 <refentry id="busctl"
  12           xmlns:xi="http://www.w3.org/2001/XInclude">
  13
  14   <refentryinfo>
  15     <title>busctl</title>
  16     <productname>systemd</productname>
  17
  18     <authorgroup>
  19       <author>
  20         <contrib>A monkey with a typewriter</contrib>
  21         <firstname>Zbigniew</firstname>
  22         <surname>Jędrzejewski-Szmek</surname>
  23         <email>zbyszek@in.waw.pl</email>
  24       </author>
  25     </authorgroup>
  26   </refentryinfo>
  27
  28   <refmeta>
  29     <refentrytitle>busctl</refentrytitle>
  30     <manvolnum>1</manvolnum>
  31   </refmeta>
  32
  33   <refnamediv>
  34     <refname>busctl</refname>
  35     <refpurpose>Introspect the bus</refpurpose>
  36   </refnamediv>
  37
  38   <refsynopsisdiv>
  39     <cmdsynopsis>
  40       <command>busctl</command>
  41       <arg choice="opt" rep="repeat">OPTIONS</arg>
  42       <arg choice="opt">COMMAND</arg>
  43       <arg choice="opt" rep="repeat"><replaceable>NAME</replaceable></arg>
  44     </cmdsynopsis>
  45   </refsynopsisdiv>
  46
  47   <refsect1>
  48     <title>Description</title>
  49
  50     <para><command>busctl</command> may be used to
  51     introspect and monitor the D-Bus bus.</para>
  52   </refsect1>
  53
  54   <refsect1>
  55     <title>Options</title>
  56
  57     <para>The following options are understood:</para>
  58
  59     <variablelist>
  60       <varlistentry>
  61           <term><option>--address=<replaceable>ADDRESS</replaceable></option></term>
  62
  63           <listitem><para>Connect to the bus specified by
  64           <replaceable>ADDRESS</replaceable> instead of using suitable
  65           defaults for either the system or user bus (see
  66           <option>--system</option> and <option>--user</option>
  67           options).</para></listitem>
  68       </varlistentry>
  69
  70       <varlistentry>
  71           <term><option>--show-machine</option></term>
  72
  73           <listitem><para>When showing the list of peers, show a
  74           column containing the names of containers they belong to.
  75           See
  76           <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  77           </para></listitem>
  78       </varlistentry>
  79
  80       <varlistentry>
  81           <term><option>--unique</option></term>
  82
  83           <listitem><para>When showing the list of peers, show only
  84           "unique" names (of the form
  85           <literal>:<replaceable>number</replaceable>.<replaceable>number</replaceable></literal>).
  86           </para></listitem>
  87       </varlistentry>
  88
  89       <varlistentry>
  90           <term><option>--acquired</option></term>
  91
  92           <listitem><para>The opposite of <option>--unique</option> —
  93           only "well-known" names will be shown.</para></listitem>
  94       </varlistentry>
  95
  96       <varlistentry>
  97           <term><option>--activatable</option></term>
  98
  99           <listitem><para>When showing the list of peers, show only
 100           peers which have actually not been activated yet, but may be
 101           started automatically if accessed.</para>
 102           </listitem>
 103       </varlistentry>
 104
 105       <varlistentry>
 106           <term><option>--match=<replaceable>MATCH</replaceable></option></term>
 107
 108           <listitem><para>When showing messages being exchanged, show only the
 109           subset matching <replaceable>MATCH</replaceable>.
 110           See
 111           <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 112           </para></listitem>
 113       </varlistentry>
 114
 115       <varlistentry>
 116         <term><option>--size=</option></term>
 117
 118         <listitem>
 119           <para>When used with the <command>capture</command> command,
 120           specifies the maximum bus message size to capture
 121           ("snaplen"). Defaults to 4096 bytes.</para>
 122         </listitem>
 123       </varlistentry>
 124
 125       <varlistentry>
 126         <term><option>--list</option></term>
 127
 128         <listitem>
 129           <para>When used with the <command>tree</command> command, shows a
 130           flat list of object paths instead of a tree.</para>
 131         </listitem>
 132       </varlistentry>
 133
 134       <varlistentry>
 135         <term><option>-q</option></term>
 136         <term><option>--quiet</option></term>
 137
 138         <listitem>
 139           <para>When used with the <command>call</command> command,
 140           suppresses display of the response message payload. Note that even
 141           if this option is specified, errors returned will still be
 142           printed and the tool will indicate success or failure with
 143           the process exit code.</para>
 144         </listitem>
 145       </varlistentry>
 146
 147       <varlistentry>
 148         <term><option>--verbose</option></term>
 149
 150         <listitem>
 151           <para>When used with the <command>call</command> or
 152           <command>get-property</command> command, shows output in a
 153           more verbose format.</para>
 154         </listitem>
 155       </varlistentry>
 156
 157       <varlistentry>
 158         <term><option>--expect-reply=</option><replaceable>BOOL</replaceable></term>
 159
 160         <listitem>
 161           <para>When used with the <command>call</command> command,
 162           specifies whether <command>busctl</command> shall wait for
 163           completion of the method call, output the returned method
 164           response data, and return success or failure via the process
 165           exit code. If this is set to <literal>no</literal>, the
 166           method call will be issued but no response is expected, the
 167           tool terminates immediately, and thus no response can be
 168           shown, and no success or failure is returned via the exit
 169           code. To only suppress output of the reply message payload,
 170           use <option>--quiet</option> above. Defaults to
 171           <literal>yes</literal>.</para>
 172         </listitem>
 173       </varlistentry>
 174
 175       <varlistentry>
 176         <term><option>--auto-start=</option><replaceable>BOOL</replaceable></term>
 177
 178         <listitem>
 179           <para>When used with the <command>call</command> command, specifies
 180           whether the method call should implicitly activate the
 181           called service, should it not be running yet but is
 182           configured to be auto-started. Defaults to
 183           <literal>yes</literal>.</para>
 184         </listitem>
 185       </varlistentry>
 186
 187       <varlistentry>
 188         <term><option>--allow-interactive-authorization=</option><replaceable>BOOL</replaceable></term>
 189
 190         <listitem>
 191           <para>When used with the <command>call</command> command,
 192           specifies whether the services may enforce interactive
 193           authorization while executing the operation, if the security
 194           policy is configured for this. Defaults to
 195           <literal>yes</literal>.</para>
 196         </listitem>
 197       </varlistentry>
 198
 199       <varlistentry>
 200         <term><option>--timeout=</option><replaceable>SECS</replaceable></term>
 201
 202         <listitem>
 203           <para>When used with the <command>call</command> command,
 204           specifies the maximum time to wait for method call
 205           completion. If no time unit is specified, assumes
 206           seconds. The usual other units are understood, too (ms, us,
 207           s, min, h, d, w, month, y). Note that this timeout does not
 208           apply if <option>--expect-reply=no</option> is used, as the
 209           tool does not wait for any reply message then. When not
 210           specified or when set to 0, the default of
 211           <literal>25s</literal> is assumed.</para>
 212         </listitem>
 213       </varlistentry>
 214
 215       <varlistentry>
 216         <term><option>--augment-creds=</option><replaceable>BOOL</replaceable></term>
 217
 218         <listitem>
 219           <para>Controls whether credential data reported by
 220           <command>list</command> or <command>status</command> shall
 221           be augmented with data from
 222           <filename>/proc</filename>. When this is turned on, the data
 223           shown is possibly inconsistent, as the data read from
 224           <filename>/proc</filename> might be more recent than the rest of
 225           the credential information. Defaults to <literal>yes</literal>.</para>
 226         </listitem>
 227       </varlistentry>
 228
 229       <varlistentry>
 230         <term><option>--watch-bind=</option><replaceable>BOOL</replaceable></term>
 231
 232         <listitem>
 233           <para>Controls whether to wait for the specified <constant>AF_UNIX</constant> bus socket to appear in the
 234           file system before connecting to it. Defaults to off. When enabled, the tool will watch the file system until
 235           the socket is created and then connect to it.</para>
 236         </listitem>
 237       </varlistentry>
 238
 239       <xi:include href="user-system-options.xml" xpointer="user" />
 240       <xi:include href="user-system-options.xml" xpointer="system" />
 241       <xi:include href="user-system-options.xml" xpointer="host" />
 242       <xi:include href="user-system-options.xml" xpointer="machine" />
 243
 244       <xi:include href="standard-options.xml" xpointer="no-pager" />
 245       <xi:include href="standard-options.xml" xpointer="no-legend" />
 246       <xi:include href="standard-options.xml" xpointer="help" />
 247       <xi:include href="standard-options.xml" xpointer="version" />
 248     </variablelist>
 249   </refsect1>
 250
 251   <refsect1>
 252     <title>Commands</title>
 253
 254     <para>The following commands are understood:</para>
 255
 256     <variablelist>
 257       <varlistentry>
 258         <term><command>list</command></term>
 259
 260         <listitem><para>Show all peers on the bus, by their service
 261         names. By default, shows both unique and well-known names, but
 262         this may be changed with the <option>--unique</option> and
 263         <option>--acquired</option> switches. This is the default
 264         operation if no command is specified.</para></listitem>
 265       </varlistentry>
 266
 267       <varlistentry>
 268         <term><command>status</command> <arg choice="opt"><replaceable>SERVICE</replaceable></arg></term>
 269
 270         <listitem><para>Show process information and credentials of a
 271         bus service (if one is specified by its unique or well-known
 272         name), a process (if one is specified by its numeric PID), or
 273         the owner of the bus (if no parameter is
 274         specified).</para></listitem>
 275       </varlistentry>
 276
 277       <varlistentry>
 278         <term><command>monitor</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 279
 280         <listitem><para>Dump messages being exchanged. If
 281         <replaceable>SERVICE</replaceable> is specified, show messages
 282         to or from this peer, identified by its well-known or unique
 283         name. Otherwise, show all messages on the bus. Use Ctrl-C to
 284         terminate the dump.</para></listitem>
 285       </varlistentry>
 286
 287       <varlistentry>
 288         <term><command>capture</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 289
 290         <listitem><para>Similar to <command>monitor</command> but
 291         writes the output in pcap format (for details, see the <ulink
 292         url="https://wiki.wireshark.org/Development/LibpcapFileFormat">Libpcap
 293         File Format</ulink> description). Make sure to redirect
 294         standard output to a file. Tools like
 295         <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 296         may be used to dissect and view the resulting
 297         files.</para></listitem>
 298       </varlistentry>
 299
 300       <varlistentry>
 301         <term><command>tree</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 302
 303         <listitem><para>Shows an object tree of one or more
 304         services. If <replaceable>SERVICE</replaceable> is specified,
 305         show object tree of the specified services only. Otherwise,
 306         show all object trees of all services on the bus that acquired
 307         at least one well-known name.</para></listitem>
 308       </varlistentry>
 309
 310       <varlistentry>
 311         <term><command>introspect</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg> <arg choice="plain"><replaceable>OBJECT</replaceable></arg> <arg choice="opt"><replaceable>INTERFACE</replaceable></arg></term>
 312
 313         <listitem><para>Show interfaces, methods, properties and
 314         signals of the specified object (identified by its path) on
 315         the specified service. If the interface argument is passed, the
 316         output is limited to members of the specified
 317         interface.</para></listitem>
 318       </varlistentry>
 319
 320       <varlistentry>
 321         <term><command>call</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg> <arg choice="plain"><replaceable>OBJECT</replaceable></arg> <arg choice="plain"><replaceable>INTERFACE</replaceable></arg> <arg choice="plain"><replaceable>METHOD</replaceable></arg> <arg choice="opt"><replaceable>SIGNATURE</replaceable> <arg choice="opt" rep="repeat"><replaceable>ARGUMENT</replaceable></arg></arg></term>
 322
 323         <listitem><para>Invoke a method and show the response. Takes a
 324         service name, object path, interface name and method name. If
 325         parameters shall be passed to the method call, a signature
 326         string is required, followed by the arguments, individually
 327         formatted as strings. For details on the formatting used, see
 328         below. To suppress output of the returned data, use the
 329         <option>--quiet</option> option.</para></listitem>
 330       </varlistentry>
 331
 332       <varlistentry>
 333         <term><command>get-property</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg> <arg choice="plain"><replaceable>OBJECT</replaceable></arg> <arg choice="plain"><replaceable>INTERFACE</replaceable></arg> <arg choice="plain" rep="repeat"><replaceable>PROPERTY</replaceable></arg></term>
 334
 335         <listitem><para>Retrieve the current value of one or more
 336         object properties. Takes a service name, object path,
 337         interface name and property name. Multiple properties may be
 338         specified at once, in which case their values will be shown one
 339         after the other, separated by newlines. The output is, by
 340         default, in terse format. Use <option>--verbose</option> for a
 341         more elaborate output format.</para></listitem>
 342       </varlistentry>
 343
 344       <varlistentry>
 345         <term><command>set-property</command> <arg choice="plain"><replaceable>SERVICE</replaceable></arg> <arg choice="plain"><replaceable>OBJECT</replaceable></arg> <arg choice="plain"><replaceable>INTERFACE</replaceable></arg> <arg choice="plain"><replaceable>PROPERTY</replaceable></arg> <arg choice="plain"><replaceable>SIGNATURE</replaceable></arg> <arg choice="plain" rep="repeat"><replaceable>ARGUMENT</replaceable></arg></term>
 346
 347         <listitem><para>Set the current value of an object
 348         property. Takes a service name, object path, interface name,
 349         property name, property signature, followed by a list of
 350         parameters formatted as strings.</para></listitem>
 351       </varlistentry>
 352
 353       <varlistentry>
 354         <term><command>help</command></term>
 355
 356         <listitem><para>Show command syntax help.</para></listitem>
 357       </varlistentry>
 358     </variablelist>
 359   </refsect1>
 360
 361   <refsect1>
 362     <title>Parameter Formatting</title>
 363
 364     <para>The <command>call</command> and
 365     <command>set-property</command> commands take a signature string
 366     followed by a list of parameters formatted as string (for details
 367     on D-Bus signature strings, see the <ulink
 368     url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">Type
 369     system chapter of the D-Bus specification</ulink>). For simple
 370     types, each parameter following the signature should simply be the
 371     parameter's value formatted as string. Positive boolean values may
 372     be formatted as <literal>true</literal>, <literal>yes</literal>,
 373     <literal>on</literal>, or <literal>1</literal>; negative boolean
 374     values may be specified as <literal>false</literal>,
 375     <literal>no</literal>, <literal>off</literal>, or
 376     <literal>0</literal>. For arrays, a numeric argument for the
 377     number of entries followed by the entries shall be specified. For
 378     variants, the signature of the contents shall be specified,
 379     followed by the contents. For dictionaries and structs, the
 380     contents of them shall be directly specified.</para>
 381
 382     <para>For example,
 383     <programlisting>s jawoll</programlisting> is the formatting
 384     of a single string <literal>jawoll</literal>.</para>
 385
 386     <para>
 387     <programlisting>as 3 hello world foobar</programlisting>
 388     is the formatting of a string array with three entries,
 389     <literal>hello</literal>, <literal>world</literal> and
 390     <literal>foobar</literal>.</para>
 391
 392     <para>
 393     <programlisting>a{sv} 3 One s Eins Two u 2 Yes b true</programlisting>
 394     is the formatting of a dictionary
 395     array that maps strings to variants, consisting of three
 396     entries. The string <literal>One</literal> is assigned the
 397     string <literal>Eins</literal>. The string
 398     <literal>Two</literal> is assigned the 32-bit unsigned
 399     integer 2. The string <literal>Yes</literal> is assigned a
 400     positive boolean.</para>
 401
 402     <para>Note that the <command>call</command>,
 403     <command>get-property</command>, <command>introspect</command>
 404     commands will also generate output in this format for the returned
 405     data. Since this format is sometimes too terse to be easily
 406     understood, the <command>call</command> and
 407     <command>get-property</command> commands may generate a more
 408     verbose, multi-line output when passed the
 409     <option>--verbose</option> option.</para>
 410   </refsect1>
 411
 412   <refsect1>
 413     <title>Examples</title>
 414
 415     <example>
 416       <title>Write and Read a Property</title>
 417
 418       <para>The following two commands first write a property and then
 419       read it back. The property is found on the
 420       <literal>/org/freedesktop/systemd1</literal> object of the
 421       <literal>org.freedesktop.systemd1</literal> service. The name of
 422       the property is <literal>LogLevel</literal> on the
 423       <literal>org.freedesktop.systemd1.Manager</literal>
 424       interface. The property contains a single string:</para>
 425
 426       <programlisting># busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel s debug
 427 # busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel
 428 s "debug"</programlisting>
 429
 430     </example>
 431
 432     <example>
 433       <title>Terse and Verbose Output</title>
 434
 435       <para>The following two commands read a property that contains
 436       an array of strings, and first show it in terse format, followed
 437       by verbose format:</para>
 438
 439       <programlisting>$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 440 as 2 "LANG=en_US.UTF-8" "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin"
 441 $ busctl get-property --verbose org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 442 ARRAY "s" {
 443         STRING "LANG=en_US.UTF-8";
 444         STRING "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";
 445 };</programlisting>
 446     </example>
 447
 448     <example>
 449       <title>Invoking a Method</title>
 450
 451       <para>The following command invokes the
 452       <literal>StartUnit</literal> method on the
 453       <literal>org.freedesktop.systemd1.Manager</literal>
 454       interface of the
 455       <literal>/org/freedesktop/systemd1</literal> object
 456       of the <literal>org.freedesktop.systemd1</literal>
 457       service, and passes it two strings
 458       <literal>cups.service</literal> and
 459       <literal>replace</literal>. As a result of the method
 460       call, a single object path parameter is received and
 461       shown:</para>
 462
 463       <programlisting># busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
 464 o "/org/freedesktop/systemd1/job/42684"</programlisting>
 465     </example>
 466   </refsect1>
 467
 468   <refsect1>
 469     <title>See Also</title>
 470
 471     <para>
 472       <citerefentry project='dbus'><refentrytitle>dbus-daemon</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 473       <ulink url="https://www.freedesktop.org/wiki/Software/dbus">D-Bus</ulink>,
 474       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 475       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 476       <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 477       <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 478     </para>
 479   </refsect1>
 480 </refentry>