man/busctl.xml

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  10   Copyright 2014 Zbigniew Jędrzejewski-Szmek
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  25
  26 <refentry id="busctl"
  27           xmlns:xi="http://www.w3.org/2001/XInclude">
  28
  29   <refentryinfo>
  30     <title>busctl</title>
  31     <productname>systemd</productname>
  32
  33     <authorgroup>
  34       <author>
  35         <contrib>A monkey with a typewriter</contrib>
  36         <firstname>Zbigniew</firstname>
  37         <surname>Jędrzejewski-Szmek</surname>
  38         <email>zbyszek@in.waw.pl</email>
  39       </author>
  40     </authorgroup>
  41   </refentryinfo>
  42
  43   <refmeta>
  44     <refentrytitle>busctl</refentrytitle>
  45     <manvolnum>1</manvolnum>
  46   </refmeta>
  47
  48   <refnamediv>
  49     <refname>busctl</refname>
  50     <refpurpose>Introspect the bus</refpurpose>
  51   </refnamediv>
  52
  53   <refsynopsisdiv>
  54     <cmdsynopsis>
  55       <command>busctl</command>
  56       <arg choice="opt" rep="repeat">OPTIONS</arg>
  57       <arg choice="opt">COMMAND</arg>
  58       <arg choice="opt" rep="repeat"><replaceable>NAME</replaceable></arg>
  59     </cmdsynopsis>
  60   </refsynopsisdiv>
  61
  62   <refsect1>
  63     <title>Description</title>
  64
  65     <para><command>busctl</command> may be used to
  66     introspect and monitor the D-Bus bus.</para>
  67   </refsect1>
  68
  69   <refsect1>
  70     <title>Options</title>
  71
  72     <para>The following options are understood:</para>
  73
  74     <variablelist>
  75       <varlistentry>
  76           <term><option>--address=<replaceable>ADDRESS</replaceable></option></term>
  77
  78           <listitem><para>Connect to the bus specified by
  79           <replaceable>ADDRESS</replaceable> instead of using suitable
  80           defaults for either the system or user bus (see
  81           <option>--system</option> and <option>--user</option>
  82           options).</para></listitem>
  83       </varlistentry>
  84
  85       <varlistentry>
  86           <term><option>--show-machine</option></term>
  87
  88           <listitem><para>When showing the list of peers, show a
  89           column containing the names of containers they belong to.
  90           See
  91           <citerefentry><refentrytitle>systemd-machined.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  92           </para></listitem>
  93       </varlistentry>
  94
  95       <varlistentry>
  96           <term><option>--unique</option></term>
  97
  98           <listitem><para>When showing the list of peers, show only
  99           "unique" names (of the form
 100           <literal>:<replaceable>number</replaceable>.<replaceable>number</replaceable></literal>).
 101           </para></listitem>
 102       </varlistentry>
 103
 104       <varlistentry>
 105           <term><option>--acquired</option></term>
 106
 107           <listitem><para>The opposite of <option>--unique</option> —
 108           only "well-known" names will be shown.</para></listitem>
 109       </varlistentry>
 110
 111       <varlistentry>
 112           <term><option>--activatable</option></term>
 113
 114           <listitem><para>When showing the list of peers, show only
 115           peers which have actually not been activated yet, but may be
 116           started automatically if accessed.</para>
 117           </listitem>
 118       </varlistentry>
 119
 120       <varlistentry>
 121           <term><option>--match=<replaceable>MATCH</replaceable></option></term>
 122
 123           <listitem><para>When showing messages being exchanged, show only the
 124           subset matching <replaceable>MATCH</replaceable>.
 125           See
 126           <citerefentry><refentrytitle>sd_bus_add_match</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 127           </para></listitem>
 128       </varlistentry>
 129
 130       <varlistentry>
 131         <term><option>--size=</option></term>
 132
 133         <listitem>
 134           <para>When used with the <command>capture</command> command,
 135           specifies the maximum bus message size to capture
 136           ("snaplen"). Defaults to 4096 bytes.</para>
 137         </listitem>
 138       </varlistentry>
 139
 140       <varlistentry>
 141         <term><option>--list</option></term>
 142
 143         <listitem>
 144           <para>When used with the <command>tree</command> command, shows a
 145           flat list of object paths instead of a tree.</para>
 146         </listitem>
 147       </varlistentry>
 148
 149       <varlistentry>
 150         <term><option>-q</option></term>
 151         <term><option>--quiet</option></term>
 152
 153         <listitem>
 154           <para>When used with the <command>call</command> command,
 155           suppresses display of the response message payload. Note that even
 156           if this option is specified, errors returned will still be
 157           printed and the tool will indicate success or failure with
 158           the process exit code.</para>
 159         </listitem>
 160       </varlistentry>
 161
 162       <varlistentry>
 163         <term><option>--verbose</option></term>
 164
 165         <listitem>
 166           <para>When used with the <command>call</command> or
 167           <command>get-property</command> command, shows output in a
 168           more verbose format.</para>
 169         </listitem>
 170       </varlistentry>
 171
 172       <varlistentry>
 173         <term><option>--expect-reply=</option><replaceable>BOOL</replaceable></term>
 174
 175         <listitem>
 176           <para>When used with the <command>call</command> command,
 177           specifies whether <command>busctl</command> shall wait for
 178           completion of the method call, output the returned method
 179           response data, and return success or failure via the process
 180           exit code. If this is set to <literal>no</literal>, the
 181           method call will be issued but no response is expected, the
 182           tool terminates immediately, and thus no response can be
 183           shown, and no success or failure is returned via the exit
 184           code. To only suppress output of the reply message payload,
 185           use <option>--quiet</option> above. Defaults to
 186           <literal>yes</literal>.</para>
 187         </listitem>
 188       </varlistentry>
 189
 190       <varlistentry>
 191         <term><option>--auto-start=</option><replaceable>BOOL</replaceable></term>
 192
 193         <listitem>
 194           <para>When used with the <command>call</command> command, specifies
 195           whether the method call should implicitly activate the
 196           called service, should it not be running yet but is
 197           configured to be auto-started. Defaults to
 198           <literal>yes</literal>.</para>
 199         </listitem>
 200       </varlistentry>
 201
 202       <varlistentry>
 203         <term><option>--allow-interactive-authorization=</option><replaceable>BOOL</replaceable></term>
 204
 205         <listitem>
 206           <para>When used with the <command>call</command> command,
 207           specifies whether the services may enforce interactive
 208           authorization while executing the operation, if the security
 209           policy is configured for this. Defaults to
 210           <literal>yes</literal>.</para>
 211         </listitem>
 212       </varlistentry>
 213
 214       <varlistentry>
 215         <term><option>--timeout=</option><replaceable>SECS</replaceable></term>
 216
 217         <listitem>
 218           <para>When used with the <command>call</command> command,
 219           specifies the maximum time to wait for method call
 220           completion. If no time unit is specified, assumes
 221           seconds. The usual other units are understood, too (ms, us,
 222           s, min, h, d, w, month, y). Note that this timeout does not
 223           apply if <option>--expect-reply=no</option> is used, as the
 224           tool does not wait for any reply message then. When not
 225           specified or when set to 0, the default of
 226           <literal>25s</literal> is assumed.</para>
 227         </listitem>
 228       </varlistentry>
 229
 230       <varlistentry>
 231         <term><option>--augment-creds=</option><replaceable>BOOL</replaceable></term>
 232
 233         <listitem>
 234           <para>Controls whether credential data reported by
 235           <command>list</command> or <command>status</command> shall
 236           be augmented with data from
 237           <filename>/proc</filename>. When this is turned on, the data
 238           shown is possibly inconsistent, as the data read from
 239           <filename>/proc</filename> might be more recent than the rest of
 240           the credential information. Defaults to <literal>yes</literal>.</para>
 241         </listitem>
 242       </varlistentry>
 243
 244       <varlistentry>
 245         <term><option>--watch-bind=</option><replaceable>BOOL</replaceable></term>
 246
 247         <listitem>
 248           <para>Controls whether to wait for the specified <constant>AF_UNIX</constant> bus socket to appear in the
 249           file system before connecting to it. Defaults to off. When enabled, the tool will watch the file system until
 250           the socket is created and then connect to it.</para>
 251         </listitem>
 252       </varlistentry>
 253
 254       <xi:include href="user-system-options.xml" xpointer="user" />
 255       <xi:include href="user-system-options.xml" xpointer="system" />
 256       <xi:include href="user-system-options.xml" xpointer="host" />
 257       <xi:include href="user-system-options.xml" xpointer="machine" />
 258
 259       <xi:include href="standard-options.xml" xpointer="no-pager" />
 260       <xi:include href="standard-options.xml" xpointer="no-legend" />
 261       <xi:include href="standard-options.xml" xpointer="help" />
 262       <xi:include href="standard-options.xml" xpointer="version" />
 263     </variablelist>
 264   </refsect1>
 265
 266   <refsect1>
 267     <title>Commands</title>
 268
 269     <para>The following commands are understood:</para>
 270
 271     <variablelist>
 272       <varlistentry>
 273         <term><command>list</command></term>
 274
 275         <listitem><para>Show all peers on the bus, by their service
 276         names. By default, shows both unique and well-known names, but
 277         this may be changed with the <option>--unique</option> and
 278         <option>--acquired</option> switches. This is the default
 279         operation if no command is specified.</para></listitem>
 280       </varlistentry>
 281
 282       <varlistentry>
 283         <term><command>status</command> <arg choice="opt"><replaceable>SERVICE</replaceable></arg></term>
 284
 285         <listitem><para>Show process information and credentials of a
 286         bus service (if one is specified by its unique or well-known
 287         name), a process (if one is specified by its numeric PID), or
 288         the owner of the bus (if no parameter is
 289         specified).</para></listitem>
 290       </varlistentry>
 291
 292       <varlistentry>
 293         <term><command>monitor</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 294
 295         <listitem><para>Dump messages being exchanged. If
 296         <replaceable>SERVICE</replaceable> is specified, show messages
 297         to or from this peer, identified by its well-known or unique
 298         name. Otherwise, show all messages on the bus. Use Ctrl-C to
 299         terminate the dump.</para></listitem>
 300       </varlistentry>
 301
 302       <varlistentry>
 303         <term><command>capture</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 304
 305         <listitem><para>Similar to <command>monitor</command> but
 306         writes the output in pcap format (for details, see the <ulink
 307         url="https://wiki.wireshark.org/Development/LibpcapFileFormat">Libpcap
 308         File Format</ulink> description). Make sure to redirect
 309         standard output to a file. Tools like
 310         <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 311         may be used to dissect and view the resulting
 312         files.</para></listitem>
 313       </varlistentry>
 314
 315       <varlistentry>
 316         <term><command>tree</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 317
 318         <listitem><para>Shows an object tree of one or more
 319         services. If <replaceable>SERVICE</replaceable> is specified,
 320         show object tree of the specified services only. Otherwise,
 321         show all object trees of all services on the bus that acquired
 322         at least one well-known name.</para></listitem>
 323       </varlistentry>
 324
 325       <varlistentry>
 326         <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>
 327
 328         <listitem><para>Show interfaces, methods, properties and
 329         signals of the specified object (identified by its path) on
 330         the specified service. If the interface argument is passed, the
 331         output is limited to members of the specified
 332         interface.</para></listitem>
 333       </varlistentry>
 334
 335       <varlistentry>
 336         <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>
 337
 338         <listitem><para>Invoke a method and show the response. Takes a
 339         service name, object path, interface name and method name. If
 340         parameters shall be passed to the method call, a signature
 341         string is required, followed by the arguments, individually
 342         formatted as strings. For details on the formatting used, see
 343         below. To suppress output of the returned data, use the
 344         <option>--quiet</option> option.</para></listitem>
 345       </varlistentry>
 346
 347       <varlistentry>
 348         <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>
 349
 350         <listitem><para>Retrieve the current value of one or more
 351         object properties. Takes a service name, object path,
 352         interface name and property name. Multiple properties may be
 353         specified at once, in which case their values will be shown one
 354         after the other, separated by newlines. The output is, by
 355         default, in terse format. Use <option>--verbose</option> for a
 356         more elaborate output format.</para></listitem>
 357       </varlistentry>
 358
 359       <varlistentry>
 360         <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>
 361
 362         <listitem><para>Set the current value of an object
 363         property. Takes a service name, object path, interface name,
 364         property name, property signature, followed by a list of
 365         parameters formatted as strings.</para></listitem>
 366       </varlistentry>
 367
 368       <varlistentry>
 369         <term><command>help</command></term>
 370
 371         <listitem><para>Show command syntax help.</para></listitem>
 372       </varlistentry>
 373     </variablelist>
 374   </refsect1>
 375
 376   <refsect1>
 377     <title>Parameter Formatting</title>
 378
 379     <para>The <command>call</command> and
 380     <command>set-property</command> commands take a signature string
 381     followed by a list of parameters formatted as string (for details
 382     on D-Bus signature strings, see the <ulink
 383     url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">Type
 384     system chapter of the D-Bus specification</ulink>). For simple
 385     types, each parameter following the signature should simply be the
 386     parameter's value formatted as string. Positive boolean values may
 387     be formatted as <literal>true</literal>, <literal>yes</literal>,
 388     <literal>on</literal>, or <literal>1</literal>; negative boolean
 389     values may be specified as <literal>false</literal>,
 390     <literal>no</literal>, <literal>off</literal>, or
 391     <literal>0</literal>. For arrays, a numeric argument for the
 392     number of entries followed by the entries shall be specified. For
 393     variants, the signature of the contents shall be specified,
 394     followed by the contents. For dictionaries and structs, the
 395     contents of them shall be directly specified.</para>
 396
 397     <para>For example,
 398     <programlisting>s jawoll</programlisting> is the formatting
 399     of a single string <literal>jawoll</literal>.</para>
 400
 401     <para>
 402     <programlisting>as 3 hello world foobar</programlisting>
 403     is the formatting of a string array with three entries,
 404     <literal>hello</literal>, <literal>world</literal> and
 405     <literal>foobar</literal>.</para>
 406
 407     <para>
 408     <programlisting>a{sv} 3 One s Eins Two u 2 Yes b true</programlisting>
 409     is the formatting of a dictionary
 410     array that maps strings to variants, consisting of three
 411     entries. The string <literal>One</literal> is assigned the
 412     string <literal>Eins</literal>. The string
 413     <literal>Two</literal> is assigned the 32-bit unsigned
 414     integer 2. The string <literal>Yes</literal> is assigned a
 415     positive boolean.</para>
 416
 417     <para>Note that the <command>call</command>,
 418     <command>get-property</command>, <command>introspect</command>
 419     commands will also generate output in this format for the returned
 420     data. Since this format is sometimes too terse to be easily
 421     understood, the <command>call</command> and
 422     <command>get-property</command> commands may generate a more
 423     verbose, multi-line output when passed the
 424     <option>--verbose</option> option.</para>
 425   </refsect1>
 426
 427   <refsect1>
 428     <title>Examples</title>
 429
 430     <example>
 431       <title>Write and Read a Property</title>
 432
 433       <para>The following two commands first write a property and then
 434       read it back. The property is found on the
 435       <literal>/org/freedesktop/systemd1</literal> object of the
 436       <literal>org.freedesktop.systemd1</literal> service. The name of
 437       the property is <literal>LogLevel</literal> on the
 438       <literal>org.freedesktop.systemd1.Manager</literal>
 439       interface. The property contains a single string:</para>
 440
 441       <programlisting># busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel s debug
 442 # busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel
 443 s "debug"</programlisting>
 444
 445     </example>
 446
 447     <example>
 448       <title>Terse and Verbose Output</title>
 449
 450       <para>The following two commands read a property that contains
 451       an array of strings, and first show it in terse format, followed
 452       by verbose format:</para>
 453
 454       <programlisting>$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 455 as 2 "LANG=en_US.UTF-8" "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin"
 456 $ busctl get-property --verbose org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 457 ARRAY "s" {
 458         STRING "LANG=en_US.UTF-8";
 459         STRING "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";
 460 };</programlisting>
 461     </example>
 462
 463     <example>
 464       <title>Invoking a Method</title>
 465
 466       <para>The following command invokes the
 467       <literal>StartUnit</literal> method on the
 468       <literal>org.freedesktop.systemd1.Manager</literal>
 469       interface of the
 470       <literal>/org/freedesktop/systemd1</literal> object
 471       of the <literal>org.freedesktop.systemd1</literal>
 472       service, and passes it two strings
 473       <literal>cups.service</literal> and
 474       <literal>replace</literal>. As a result of the method
 475       call, a single object path parameter is received and
 476       shown:</para>
 477
 478       <programlisting># busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
 479 o "/org/freedesktop/systemd1/job/42684"</programlisting>
 480     </example>
 481   </refsect1>
 482
 483   <refsect1>
 484     <title>See Also</title>
 485
 486     <para>
 487       <citerefentry project='dbus'><refentrytitle>dbus-daemon</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 488       <ulink url="https://www.freedesktop.org/wiki/Software/dbus">D-Bus</ulink>,
 489       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 490       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 491       <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 492       <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 493     </para>
 494   </refsect1>
 495 </refentry>