man/busctl.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="busctl"
   7           xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>busctl</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>busctl</refentrytitle>
  16     <manvolnum>1</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>busctl</refname>
  21     <refpurpose>Introspect the bus</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <cmdsynopsis>
  26       <command>busctl</command>
  27       <arg choice="opt" rep="repeat">OPTIONS</arg>
  28       <arg choice="opt">COMMAND</arg>
  29       <arg choice="opt" rep="repeat"><replaceable>NAME</replaceable></arg>
  30     </cmdsynopsis>
  31   </refsynopsisdiv>
  32
  33   <refsect1>
  34     <title>Description</title>
  35
  36     <para><command>busctl</command> may be used to
  37     introspect and monitor the D-Bus bus.</para>
  38   </refsect1>
  39
  40   <refsect1>
  41     <title>Commands</title>
  42
  43     <para>The following commands are understood:</para>
  44
  45     <variablelist>
  46       <varlistentry>
  47         <term><command>list</command></term>
  48
  49         <listitem><para>Show all peers on the bus, by their service
  50         names. By default, shows both unique and well-known names, but
  51         this may be changed with the <option>--unique</option> and
  52         <option>--acquired</option> switches. This is the default
  53         operation if no command is specified.</para></listitem>
  54       </varlistentry>
  55
  56       <varlistentry>
  57         <term><command>status</command> <arg choice="opt"><replaceable>SERVICE</replaceable></arg></term>
  58
  59         <listitem><para>Show process information and credentials of a
  60         bus service (if one is specified by its unique or well-known
  61         name), a process (if one is specified by its numeric PID), or
  62         the owner of the bus (if no parameter is
  63         specified).</para></listitem>
  64       </varlistentry>
  65
  66       <varlistentry>
  67         <term><command>monitor</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
  68
  69         <listitem><para>Dump messages being exchanged. If
  70         <replaceable>SERVICE</replaceable> is specified, show messages
  71         to or from this peer, identified by its well-known or unique
  72         name. Otherwise, show all messages on the bus. Use
  73         <keycombo><keycap>Ctrl</keycap><keycap>C</keycap></keycombo>
  74         to terminate the dump.</para></listitem>
  75       </varlistentry>
  76
  77       <varlistentry>
  78         <term><command>capture</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
  79
  80         <listitem><para>Similar to <command>monitor</command> but
  81         writes the output in pcap format (for details, see the <ulink
  82         url="https://wiki.wireshark.org/Development/LibpcapFileFormat">Libpcap
  83         File Format</ulink> description). Make sure to redirect
  84         standard output to a file. Tools like
  85         <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  86         may be used to dissect and view the resulting
  87         files.</para></listitem>
  88       </varlistentry>
  89
  90       <varlistentry>
  91         <term><command>tree</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
  92
  93         <listitem><para>Shows an object tree of one or more
  94         services. If <replaceable>SERVICE</replaceable> is specified,
  95         show object tree of the specified services only. Otherwise,
  96         show all object trees of all services on the bus that acquired
  97         at least one well-known name.</para></listitem>
  98       </varlistentry>
  99
 100       <varlistentry>
 101         <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>
 102
 103         <listitem><para>Show interfaces, methods, properties and
 104         signals of the specified object (identified by its path) on
 105         the specified service. If the interface argument is passed, the
 106         output is limited to members of the specified
 107         interface.</para></listitem>
 108       </varlistentry>
 109
 110       <varlistentry>
 111         <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>
 112
 113         <listitem><para>Invoke a method and show the response. Takes a
 114         service name, object path, interface name and method name. If
 115         parameters shall be passed to the method call, a signature
 116         string is required, followed by the arguments, individually
 117         formatted as strings. For details on the formatting used, see
 118         below. To suppress output of the returned data, use the
 119         <option>--quiet</option> option.</para></listitem>
 120       </varlistentry>
 121
 122       <varlistentry>
 123         <term><command>emit</command> <arg choice="plain"><replaceable>OBJECT</replaceable></arg> <arg choice="plain"><replaceable>INTERFACE</replaceable></arg> <arg choice="plain"><replaceable>SIGNAL</replaceable></arg> <arg choice="opt"><replaceable>SIGNATURE</replaceable> <arg choice="opt" rep="repeat"><replaceable>ARGUMENT</replaceable></arg></arg></term>
 124
 125         <listitem><para>Emit a signal. Takes a object path, interface name and method name. If parameters
 126         shall be passed, a signature string is required, followed by the arguments, individually formatted as
 127         strings. For details on the formatting used, see below. To specify the destination of the signal,
 128         use the <option>--destination=</option> option.</para></listitem>
 129       </varlistentry>
 130
 131       <varlistentry>
 132         <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>
 133
 134         <listitem><para>Retrieve the current value of one or more
 135         object properties. Takes a service name, object path,
 136         interface name and property name. Multiple properties may be
 137         specified at once, in which case their values will be shown one
 138         after the other, separated by newlines. The output is, by
 139         default, in terse format. Use <option>--verbose</option> for a
 140         more elaborate output format.</para></listitem>
 141       </varlistentry>
 142
 143       <varlistentry>
 144         <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>
 145
 146         <listitem><para>Set the current value of an object
 147         property. Takes a service name, object path, interface name,
 148         property name, property signature, followed by a list of
 149         parameters formatted as strings.</para></listitem>
 150       </varlistentry>
 151
 152       <varlistentry>
 153         <term><command>help</command></term>
 154
 155         <listitem><para>Show command syntax help.</para></listitem>
 156       </varlistentry>
 157     </variablelist>
 158   </refsect1>
 159
 160   <refsect1>
 161     <title>Options</title>
 162
 163     <para>The following options are understood:</para>
 164
 165     <variablelist>
 166       <varlistentry>
 167           <term><option>--address=<replaceable>ADDRESS</replaceable></option></term>
 168
 169           <listitem><para>Connect to the bus specified by
 170           <replaceable>ADDRESS</replaceable> instead of using suitable
 171           defaults for either the system or user bus (see
 172           <option>--system</option> and <option>--user</option>
 173           options).</para></listitem>
 174       </varlistentry>
 175
 176       <varlistentry>
 177           <term><option>--show-machine</option></term>
 178
 179           <listitem><para>When showing the list of peers, show a
 180           column containing the names of containers they belong to.
 181           See
 182           <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
 183           </para></listitem>
 184       </varlistentry>
 185
 186       <varlistentry>
 187           <term><option>--unique</option></term>
 188
 189           <listitem><para>When showing the list of peers, show only
 190           "unique" names (of the form
 191           <literal>:<replaceable>number</replaceable>.<replaceable>number</replaceable></literal>).
 192           </para></listitem>
 193       </varlistentry>
 194
 195       <varlistentry>
 196           <term><option>--acquired</option></term>
 197
 198           <listitem><para>The opposite of <option>--unique</option> —
 199           only "well-known" names will be shown.</para></listitem>
 200       </varlistentry>
 201
 202       <varlistentry>
 203           <term><option>--activatable</option></term>
 204
 205           <listitem><para>When showing the list of peers, show only
 206           peers which have actually not been activated yet, but may be
 207           started automatically if accessed.</para>
 208           </listitem>
 209       </varlistentry>
 210
 211       <varlistentry>
 212           <term><option>--match=<replaceable>MATCH</replaceable></option></term>
 213
 214           <listitem><para>When showing messages being exchanged, show only the
 215           subset matching <replaceable>MATCH</replaceable>.
 216           See
 217           <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 218           </para></listitem>
 219       </varlistentry>
 220
 221       <varlistentry>
 222         <term><option>--size=</option></term>
 223
 224         <listitem>
 225           <para>When used with the <command>capture</command> command,
 226           specifies the maximum bus message size to capture
 227           ("snaplen"). Defaults to 4096 bytes.</para>
 228         </listitem>
 229       </varlistentry>
 230
 231       <varlistentry>
 232         <term><option>--list</option></term>
 233
 234         <listitem>
 235           <para>When used with the <command>tree</command> command, shows a
 236           flat list of object paths instead of a tree.</para>
 237         </listitem>
 238       </varlistentry>
 239
 240       <varlistentry>
 241         <term><option>-q</option></term>
 242         <term><option>--quiet</option></term>
 243
 244         <listitem>
 245           <para>When used with the <command>call</command> command,
 246           suppresses display of the response message payload. Note that even
 247           if this option is specified, errors returned will still be
 248           printed and the tool will indicate success or failure with
 249           the process exit code.</para>
 250         </listitem>
 251       </varlistentry>
 252
 253       <varlistentry>
 254         <term><option>--verbose</option></term>
 255
 256         <listitem>
 257           <para>When used with the <command>call</command> or
 258           <command>get-property</command> command, shows output in a
 259           more verbose format.</para>
 260         </listitem>
 261       </varlistentry>
 262
 263       <varlistentry>
 264         <term><option>--xml-interface</option></term>
 265
 266         <listitem>
 267           <para>When used with the <command>introspect</command> call, dump the XML description received from
 268           the D-Bus <constant>org.freedesktop.DBus.Introspectable.Introspect</constant> call instead of the
 269           normal output.</para>
 270         </listitem>
 271       </varlistentry>
 272
 273       <varlistentry>
 274         <term><option>--json=</option><replaceable>MODE</replaceable></term>
 275
 276         <listitem>
 277           <para>When used with the <command>call</command> or <command>get-property</command> command, shows output
 278           formatted as JSON. Expects one of <literal>short</literal> (for the shortest possible output without any
 279           redundant whitespace or line breaks) or <literal>pretty</literal> (for a pretty version of the same, with
 280           indentation and line breaks). Note that transformation from D-Bus marshalling to JSON is done in a loss-less
 281           way, which means type information is embedded into the JSON object tree.</para>
 282         </listitem>
 283       </varlistentry>
 284
 285       <varlistentry>
 286         <term><option>-j</option></term>
 287
 288         <listitem>
 289           <para>Equivalent to <option>--json=pretty</option> when invoked interactively from a terminal. Otherwise
 290           equivalent to <option>--json=short</option>, in particular when the output is piped to some other
 291           program.</para>
 292         </listitem>
 293       </varlistentry>
 294
 295       <varlistentry>
 296         <term><option>--expect-reply=</option><replaceable>BOOL</replaceable></term>
 297
 298         <listitem>
 299           <para>When used with the <command>call</command> command,
 300           specifies whether <command>busctl</command> shall wait for
 301           completion of the method call, output the returned method
 302           response data, and return success or failure via the process
 303           exit code. If this is set to <literal>no</literal>, the
 304           method call will be issued but no response is expected, the
 305           tool terminates immediately, and thus no response can be
 306           shown, and no success or failure is returned via the exit
 307           code. To only suppress output of the reply message payload,
 308           use <option>--quiet</option> above. Defaults to
 309           <literal>yes</literal>.</para>
 310         </listitem>
 311       </varlistentry>
 312
 313       <varlistentry>
 314         <term><option>--auto-start=</option><replaceable>BOOL</replaceable></term>
 315
 316         <listitem>
 317           <para>When used with the <command>call</command> or <command>emit</command> command, specifies
 318           whether the method call should implicitly activate the
 319           called service, should it not be running yet but is
 320           configured to be auto-started. Defaults to
 321           <literal>yes</literal>.</para>
 322         </listitem>
 323       </varlistentry>
 324
 325       <varlistentry>
 326         <term><option>--allow-interactive-authorization=</option><replaceable>BOOL</replaceable></term>
 327
 328         <listitem>
 329           <para>When used with the <command>call</command> command,
 330           specifies whether the services may enforce interactive
 331           authorization while executing the operation, if the security
 332           policy is configured for this. Defaults to
 333           <literal>yes</literal>.</para>
 334         </listitem>
 335       </varlistentry>
 336
 337       <varlistentry>
 338         <term><option>--timeout=</option><replaceable>SECS</replaceable></term>
 339
 340         <listitem>
 341           <para>When used with the <command>call</command> command,
 342           specifies the maximum time to wait for method call
 343           completion. If no time unit is specified, assumes
 344           seconds. The usual other units are understood, too (ms, us,
 345           s, min, h, d, w, month, y). Note that this timeout does not
 346           apply if <option>--expect-reply=no</option> is used, as the
 347           tool does not wait for any reply message then. When not
 348           specified or when set to 0, the default of
 349           <literal>25s</literal> is assumed.</para>
 350         </listitem>
 351       </varlistentry>
 352
 353       <varlistentry>
 354         <term><option>--augment-creds=</option><replaceable>BOOL</replaceable></term>
 355
 356         <listitem>
 357           <para>Controls whether credential data reported by
 358           <command>list</command> or <command>status</command> shall
 359           be augmented with data from
 360           <filename>/proc</filename>. When this is turned on, the data
 361           shown is possibly inconsistent, as the data read from
 362           <filename>/proc</filename> might be more recent than the rest of
 363           the credential information. Defaults to <literal>yes</literal>.</para>
 364         </listitem>
 365       </varlistentry>
 366
 367       <varlistentry>
 368         <term><option>--watch-bind=</option><replaceable>BOOL</replaceable></term>
 369
 370         <listitem>
 371           <para>Controls whether to wait for the specified <constant>AF_UNIX</constant> bus socket to appear in the
 372           file system before connecting to it. Defaults to off. When enabled, the tool will watch the file system until
 373           the socket is created and then connect to it.</para>
 374         </listitem>
 375       </varlistentry>
 376
 377       <varlistentry>
 378         <term><option>--destination=</option><replaceable>SERVICE</replaceable></term>
 379
 380         <listitem>
 381           <para>Takes a service name. When used with the <command>emit</command> command, a signal is
 382           emitted to the specified service.</para>
 383         </listitem>
 384       </varlistentry>
 385
 386       <xi:include href="user-system-options.xml" xpointer="user" />
 387       <xi:include href="user-system-options.xml" xpointer="system" />
 388       <xi:include href="user-system-options.xml" xpointer="host" />
 389       <xi:include href="user-system-options.xml" xpointer="machine" />
 390
 391       <varlistentry>
 392         <term><option>-l</option></term>
 393         <term><option>--full</option></term>
 394
 395         <listitem>
 396           <para>Do not ellipsize the output in <command>list</command> command.</para>
 397         </listitem>
 398       </varlistentry>
 399
 400       <xi:include href="standard-options.xml" xpointer="no-pager" />
 401       <xi:include href="standard-options.xml" xpointer="no-legend" />
 402       <xi:include href="standard-options.xml" xpointer="help" />
 403       <xi:include href="standard-options.xml" xpointer="version" />
 404     </variablelist>
 405   </refsect1>
 406
 407   <refsect1>
 408     <title>Parameter Formatting</title>
 409
 410     <para>The <command>call</command> and
 411     <command>set-property</command> commands take a signature string
 412     followed by a list of parameters formatted as string (for details
 413     on D-Bus signature strings, see the <ulink
 414     url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">Type
 415     system chapter of the D-Bus specification</ulink>). For simple
 416     types, each parameter following the signature should simply be the
 417     parameter's value formatted as string. Positive boolean values may
 418     be formatted as <literal>true</literal>, <literal>yes</literal>,
 419     <literal>on</literal>, or <literal>1</literal>; negative boolean
 420     values may be specified as <literal>false</literal>,
 421     <literal>no</literal>, <literal>off</literal>, or
 422     <literal>0</literal>. For arrays, a numeric argument for the
 423     number of entries followed by the entries shall be specified. For
 424     variants, the signature of the contents shall be specified,
 425     followed by the contents. For dictionaries and structs, the
 426     contents of them shall be directly specified.</para>
 427
 428     <para>For example,
 429     <programlisting>s jawoll</programlisting> is the formatting
 430     of a single string <literal>jawoll</literal>.</para>
 431
 432     <para>
 433     <programlisting>as 3 hello world foobar</programlisting>
 434     is the formatting of a string array with three entries,
 435     <literal>hello</literal>, <literal>world</literal> and
 436     <literal>foobar</literal>.</para>
 437
 438     <para>
 439     <programlisting>a{sv} 3 One s Eins Two u 2 Yes b true</programlisting>
 440     is the formatting of a dictionary
 441     array that maps strings to variants, consisting of three
 442     entries. The string <literal>One</literal> is assigned the
 443     string <literal>Eins</literal>. The string
 444     <literal>Two</literal> is assigned the 32-bit unsigned
 445     integer 2. The string <literal>Yes</literal> is assigned a
 446     positive boolean.</para>
 447
 448     <para>Note that the <command>call</command>,
 449     <command>get-property</command>, <command>introspect</command>
 450     commands will also generate output in this format for the returned
 451     data. Since this format is sometimes too terse to be easily
 452     understood, the <command>call</command> and
 453     <command>get-property</command> commands may generate a more
 454     verbose, multi-line output when passed the
 455     <option>--verbose</option> option.</para>
 456   </refsect1>
 457
 458   <refsect1>
 459     <title>Examples</title>
 460
 461     <example>
 462       <title>Write and Read a Property</title>
 463
 464       <para>The following two commands first write a property and then
 465       read it back. The property is found on the
 466       <literal>/org/freedesktop/systemd1</literal> object of the
 467       <literal>org.freedesktop.systemd1</literal> service. The name of
 468       the property is <literal>LogLevel</literal> on the
 469       <literal>org.freedesktop.systemd1.Manager</literal>
 470       interface. The property contains a single string:</para>
 471
 472       <programlisting># busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel s debug
 473 # busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel
 474 s "debug"</programlisting>
 475
 476     </example>
 477
 478     <example>
 479       <title>Terse and Verbose Output</title>
 480
 481       <para>The following two commands read a property that contains
 482       an array of strings, and first show it in terse format, followed
 483       by verbose format:</para>
 484
 485       <programlisting>$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 486 as 2 "LANG=en_US.UTF-8" "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin"
 487 $ busctl get-property --verbose org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 488 ARRAY "s" {
 489         STRING "LANG=en_US.UTF-8";
 490         STRING "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";
 491 };</programlisting>
 492     </example>
 493
 494     <example>
 495       <title>Invoking a Method</title>
 496
 497       <para>The following command invokes the
 498       <literal>StartUnit</literal> method on the
 499       <literal>org.freedesktop.systemd1.Manager</literal>
 500       interface of the
 501       <literal>/org/freedesktop/systemd1</literal> object
 502       of the <literal>org.freedesktop.systemd1</literal>
 503       service, and passes it two strings
 504       <literal>cups.service</literal> and
 505       <literal>replace</literal>. As a result of the method
 506       call, a single object path parameter is received and
 507       shown:</para>
 508
 509       <programlisting># busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
 510 o "/org/freedesktop/systemd1/job/42684"</programlisting>
 511     </example>
 512   </refsect1>
 513
 514   <refsect1>
 515     <title>See Also</title>
 516
 517     <para>
 518       <citerefentry project='dbus'><refentrytitle>dbus-daemon</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 519       <ulink url="https://www.freedesktop.org/wiki/Software/dbus">D-Bus</ulink>,
 520       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 521       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 522       <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 523       <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 524     </para>
 525   </refsect1>
 526 </refentry>