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>--quiet</option></term>
 151
 152         <listitem>
 153           <para>When used with the <command>call</command> command,
 154           suppresses display of the response message payload. Note that even
 155           if this option is specified, errors returned will still be
 156           printed and the tool will indicate success or failure with
 157           the process exit code.</para>
 158         </listitem>
 159       </varlistentry>
 160
 161       <varlistentry>
 162         <term><option>--verbose</option></term>
 163
 164         <listitem>
 165           <para>When used with the <command>call</command> or
 166           <command>get-property</command> command, shows output in a
 167           more verbose format.</para>
 168         </listitem>
 169       </varlistentry>
 170
 171       <varlistentry>
 172         <term><option>--expect-reply=</option><replaceable>BOOL</replaceable></term>
 173
 174         <listitem>
 175           <para>When used with the <command>call</command> command,
 176           specifies whether <command>busctl</command> shall wait for
 177           completion of the method call, output the returned method
 178           response data, and return success or failure via the process
 179           exit code. If this is set to <literal>no</literal>, the
 180           method call will be issued but no response is expected, the
 181           tool terminates immediately, and thus no response can be
 182           shown, and no success or failure is returned via the exit
 183           code. To only suppress output of the reply message payload,
 184           use <option>--quiet</option> above. Defaults to
 185           <literal>yes</literal>.</para>
 186         </listitem>
 187       </varlistentry>
 188
 189       <varlistentry>
 190         <term><option>--auto-start=</option><replaceable>BOOL</replaceable></term>
 191
 192         <listitem>
 193           <para>When used with the <command>call</command> command, specifies
 194           whether the method call should implicitly activate the
 195           called service, should it not be running yet but is
 196           configured to be auto-started. Defaults to
 197           <literal>yes</literal>.</para>
 198         </listitem>
 199       </varlistentry>
 200
 201       <varlistentry>
 202         <term><option>--allow-interactive-authorization=</option><replaceable>BOOL</replaceable></term>
 203
 204         <listitem>
 205           <para>When used with the <command>call</command> command,
 206           specifies whether the services may enforce interactive
 207           authorization while executing the operation, if the security
 208           policy is configured for this. Defaults to
 209           <literal>yes</literal>.</para>
 210         </listitem>
 211       </varlistentry>
 212
 213       <varlistentry>
 214         <term><option>--timeout=</option><replaceable>SECS</replaceable></term>
 215
 216         <listitem>
 217           <para>When used with the <command>call</command> command,
 218           specifies the maximum time to wait for method call
 219           completion. If no time unit is specified, assumes
 220           seconds. The usual other units are understood, too (ms, us,
 221           s, min, h, d, w, month, y). Note that this timeout does not
 222           apply if <option>--expect-reply=no</option> is used, as the
 223           tool does not wait for any reply message then. When not
 224           specified or when set to 0, the default of
 225           <literal>25s</literal> is assumed.</para>
 226         </listitem>
 227       </varlistentry>
 228
 229       <varlistentry>
 230         <term><option>--augment-creds=</option><replaceable>BOOL</replaceable></term>
 231
 232         <listitem>
 233           <para>Controls whether credential data reported by
 234           <command>list</command> or <command>status</command> shall
 235           be augmented with data from
 236           <filename>/proc</filename>. When this is turned on, the data
 237           shown is possibly inconsistent, as the data read from
 238           <filename>/proc</filename> might be more recent than the rest of
 239           the credential information. Defaults to <literal>yes</literal>.</para>
 240         </listitem>
 241       </varlistentry>
 242
 243       <xi:include href="user-system-options.xml" xpointer="user" />
 244       <xi:include href="user-system-options.xml" xpointer="system" />
 245       <xi:include href="user-system-options.xml" xpointer="host" />
 246       <xi:include href="user-system-options.xml" xpointer="machine" />
 247
 248       <xi:include href="standard-options.xml" xpointer="no-pager" />
 249       <xi:include href="standard-options.xml" xpointer="no-legend" />
 250       <xi:include href="standard-options.xml" xpointer="help" />
 251       <xi:include href="standard-options.xml" xpointer="version" />
 252     </variablelist>
 253   </refsect1>
 254
 255   <refsect1>
 256     <title>Commands</title>
 257
 258     <para>The following commands are understood:</para>
 259
 260     <variablelist>
 261       <varlistentry>
 262         <term><command>list</command></term>
 263
 264         <listitem><para>Show all peers on the bus, by their service
 265         names. By default, shows both unique and well-known names, but
 266         this may be changed with the <option>--unique</option> and
 267         <option>--acquired</option> switches. This is the default
 268         operation if no command is specified.</para></listitem>
 269       </varlistentry>
 270
 271       <varlistentry>
 272         <term><command>status</command> <arg choice="opt"><replaceable>SERVICE</replaceable></arg></term>
 273
 274         <listitem><para>Show process information and credentials of a
 275         bus service (if one is specified by its unique or well-known
 276         name), a process (if one is specified by its numeric PID), or
 277         the owner of the bus (if no parameter is
 278         specified).</para></listitem>
 279       </varlistentry>
 280
 281       <varlistentry>
 282         <term><command>monitor</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 283
 284         <listitem><para>Dump messages being exchanged. If
 285         <replaceable>SERVICE</replaceable> is specified, show messages
 286         to or from this peer, identified by its well-known or unique
 287         name. Otherwise, show all messages on the bus. Use Ctrl-C to
 288         terminate the dump.</para></listitem>
 289       </varlistentry>
 290
 291       <varlistentry>
 292         <term><command>capture</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 293
 294         <listitem><para>Similar to <command>monitor</command> but
 295         writes the output in pcap format (for details, see the <ulink
 296         url="https://wiki.wireshark.org/Development/LibpcapFileFormat">Libpcap
 297         File Format</ulink> description). Make sure to redirect
 298         standard output to a file. Tools like
 299         <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 300         may be used to dissect and view the resulting
 301         files.</para></listitem>
 302       </varlistentry>
 303
 304       <varlistentry>
 305         <term><command>tree</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 306
 307         <listitem><para>Shows an object tree of one or more
 308         services. If <replaceable>SERVICE</replaceable> is specified,
 309         show object tree of the specified services only. Otherwise,
 310         show all object trees of all services on the bus that acquired
 311         at least one well-known name.</para></listitem>
 312       </varlistentry>
 313
 314       <varlistentry>
 315         <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>
 316
 317         <listitem><para>Show interfaces, methods, properties and
 318         signals of the specified object (identified by its path) on
 319         the specified service. If the interface argument is passed, the
 320         output is limited to members of the specified
 321         interface.</para></listitem>
 322       </varlistentry>
 323
 324       <varlistentry>
 325         <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>
 326
 327         <listitem><para>Invoke a method and show the response. Takes a
 328         service name, object path, interface name and method name. If
 329         parameters shall be passed to the method call, a signature
 330         string is required, followed by the arguments, individually
 331         formatted as strings. For details on the formatting used, see
 332         below. To suppress output of the returned data, use the
 333         <option>--quiet</option> option.</para></listitem>
 334       </varlistentry>
 335
 336       <varlistentry>
 337         <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>
 338
 339         <listitem><para>Retrieve the current value of one or more
 340         object properties. Takes a service name, object path,
 341         interface name and property name. Multiple properties may be
 342         specified at once, in which case their values will be shown one
 343         after the other, separated by newlines. The output is, by
 344         default, in terse format. Use <option>--verbose</option> for a
 345         more elaborate output format.</para></listitem>
 346       </varlistentry>
 347
 348       <varlistentry>
 349         <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>
 350
 351         <listitem><para>Set the current value of an object
 352         property. Takes a service name, object path, interface name,
 353         property name, property signature, followed by a list of
 354         parameters formatted as strings.</para></listitem>
 355       </varlistentry>
 356
 357       <varlistentry>
 358         <term><command>help</command></term>
 359
 360         <listitem><para>Show command syntax help.</para></listitem>
 361       </varlistentry>
 362     </variablelist>
 363   </refsect1>
 364
 365   <refsect1>
 366     <title>Parameter Formatting</title>
 367
 368     <para>The <command>call</command> and
 369     <command>set-property</command> commands take a signature string
 370     followed by a list of parameters formatted as string (for details
 371     on D-Bus signature strings, see the <ulink
 372     url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">Type
 373     system chapter of the D-Bus specification</ulink>). For simple
 374     types, each parameter following the signature should simply be the
 375     parameter's value formatted as string. Positive boolean values may
 376     be formatted as <literal>true</literal>, <literal>yes</literal>,
 377     <literal>on</literal>, or <literal>1</literal>; negative boolean
 378     values may be specified as <literal>false</literal>,
 379     <literal>no</literal>, <literal>off</literal>, or
 380     <literal>0</literal>. For arrays, a numeric argument for the
 381     number of entries followed by the entries shall be specified. For
 382     variants, the signature of the contents shall be specified,
 383     followed by the contents. For dictionaries and structs, the
 384     contents of them shall be directly specified.</para>
 385
 386     <para>For example,
 387     <programlisting>s jawoll</programlisting> is the formatting
 388     of a single string <literal>jawoll</literal>.</para>
 389
 390     <para>
 391     <programlisting>as 3 hello world foobar</programlisting>
 392     is the formatting of a string array with three entries,
 393     <literal>hello</literal>, <literal>world</literal> and
 394     <literal>foobar</literal>.</para>
 395
 396     <para>
 397     <programlisting>a{sv} 3 One s Eins Two u 2 Yes b true</programlisting>
 398     is the formatting of a dictionary
 399     array that maps strings to variants, consisting of three
 400     entries. The string <literal>One</literal> is assigned the
 401     string <literal>Eins</literal>. The string
 402     <literal>Two</literal> is assigned the 32-bit unsigned
 403     integer 2. The string <literal>Yes</literal> is assigned a
 404     positive boolean.</para>
 405
 406     <para>Note that the <command>call</command>,
 407     <command>get-property</command>, <command>introspect</command>
 408     commands will also generate output in this format for the returned
 409     data. Since this format is sometimes too terse to be easily
 410     understood, the <command>call</command> and
 411     <command>get-property</command> commands may generate a more
 412     verbose, multi-line output when passed the
 413     <option>--verbose</option> option.</para>
 414   </refsect1>
 415
 416   <refsect1>
 417     <title>Examples</title>
 418
 419     <example>
 420       <title>Write and Read a Property</title>
 421
 422       <para>The following two commands first write a property and then
 423       read it back. The property is found on the
 424       <literal>/org/freedesktop/systemd1</literal> object of the
 425       <literal>org.freedesktop.systemd1</literal> service. The name of
 426       the property is <literal>LogLevel</literal> on the
 427       <literal>org.freedesktop.systemd1.Manager</literal>
 428       interface. The property contains a single string:</para>
 429
 430       <programlisting># busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel s debug
 431 # busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel
 432 s "debug"</programlisting>
 433
 434     </example>
 435
 436     <example>
 437       <title>Terse and Verbose Output</title>
 438
 439       <para>The following two commands read a property that contains
 440       an array of strings, and first show it in terse format, followed
 441       by verbose format:</para>
 442
 443       <programlisting>$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 444 as 2 "LANG=en_US.UTF-8" "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin"
 445 $ busctl get-property --verbose org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 446 ARRAY "s" {
 447         STRING "LANG=en_US.UTF-8";
 448         STRING "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";
 449 };</programlisting>
 450     </example>
 451
 452     <example>
 453       <title>Invoking a Method</title>
 454
 455       <para>The following command invokes the
 456       <literal>StartUnit</literal> method on the
 457       <literal>org.freedesktop.systemd1.Manager</literal>
 458       interface of the
 459       <literal>/org/freedesktop/systemd1</literal> object
 460       of the <literal>org.freedesktop.systemd1</literal>
 461       service, and passes it two strings
 462       <literal>cups.service</literal> and
 463       <literal>replace</literal>. As a result of the method
 464       call, a single object path parameter is received and
 465       shown:</para>
 466
 467       <programlisting># busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
 468 o "/org/freedesktop/systemd1/job/42684"</programlisting>
 469     </example>
 470   </refsect1>
 471
 472   <refsect1>
 473     <title>See Also</title>
 474
 475     <para>
 476       <citerefentry project='dbus'><refentrytitle>dbus-daemon</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 477       <ulink url="https://www.freedesktop.org/wiki/Software/dbus">D-Bus</ulink>,
 478       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 479       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 480       <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 481       <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 482     </para>
 483   </refsect1>
 484 </refentry>