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       <xi:include href="user-system-options.xml" xpointer="user" />
 245       <xi:include href="user-system-options.xml" xpointer="system" />
 246       <xi:include href="user-system-options.xml" xpointer="host" />
 247       <xi:include href="user-system-options.xml" xpointer="machine" />
 248
 249       <xi:include href="standard-options.xml" xpointer="no-pager" />
 250       <xi:include href="standard-options.xml" xpointer="no-legend" />
 251       <xi:include href="standard-options.xml" xpointer="help" />
 252       <xi:include href="standard-options.xml" xpointer="version" />
 253     </variablelist>
 254   </refsect1>
 255
 256   <refsect1>
 257     <title>Commands</title>
 258
 259     <para>The following commands are understood:</para>
 260
 261     <variablelist>
 262       <varlistentry>
 263         <term><command>list</command></term>
 264
 265         <listitem><para>Show all peers on the bus, by their service
 266         names. By default, shows both unique and well-known names, but
 267         this may be changed with the <option>--unique</option> and
 268         <option>--acquired</option> switches. This is the default
 269         operation if no command is specified.</para></listitem>
 270       </varlistentry>
 271
 272       <varlistentry>
 273         <term><command>status</command> <arg choice="opt"><replaceable>SERVICE</replaceable></arg></term>
 274
 275         <listitem><para>Show process information and credentials of a
 276         bus service (if one is specified by its unique or well-known
 277         name), a process (if one is specified by its numeric PID), or
 278         the owner of the bus (if no parameter is
 279         specified).</para></listitem>
 280       </varlistentry>
 281
 282       <varlistentry>
 283         <term><command>monitor</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 284
 285         <listitem><para>Dump messages being exchanged. If
 286         <replaceable>SERVICE</replaceable> is specified, show messages
 287         to or from this peer, identified by its well-known or unique
 288         name. Otherwise, show all messages on the bus. Use Ctrl-C to
 289         terminate the dump.</para></listitem>
 290       </varlistentry>
 291
 292       <varlistentry>
 293         <term><command>capture</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 294
 295         <listitem><para>Similar to <command>monitor</command> but
 296         writes the output in pcap format (for details, see the <ulink
 297         url="https://wiki.wireshark.org/Development/LibpcapFileFormat">Libpcap
 298         File Format</ulink> description). Make sure to redirect
 299         standard output to a file. Tools like
 300         <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 301         may be used to dissect and view the resulting
 302         files.</para></listitem>
 303       </varlistentry>
 304
 305       <varlistentry>
 306         <term><command>tree</command> <arg choice="opt" rep="repeat"><replaceable>SERVICE</replaceable></arg></term>
 307
 308         <listitem><para>Shows an object tree of one or more
 309         services. If <replaceable>SERVICE</replaceable> is specified,
 310         show object tree of the specified services only. Otherwise,
 311         show all object trees of all services on the bus that acquired
 312         at least one well-known name.</para></listitem>
 313       </varlistentry>
 314
 315       <varlistentry>
 316         <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>
 317
 318         <listitem><para>Show interfaces, methods, properties and
 319         signals of the specified object (identified by its path) on
 320         the specified service. If the interface argument is passed, the
 321         output is limited to members of the specified
 322         interface.</para></listitem>
 323       </varlistentry>
 324
 325       <varlistentry>
 326         <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>
 327
 328         <listitem><para>Invoke a method and show the response. Takes a
 329         service name, object path, interface name and method name. If
 330         parameters shall be passed to the method call, a signature
 331         string is required, followed by the arguments, individually
 332         formatted as strings. For details on the formatting used, see
 333         below. To suppress output of the returned data, use the
 334         <option>--quiet</option> option.</para></listitem>
 335       </varlistentry>
 336
 337       <varlistentry>
 338         <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>
 339
 340         <listitem><para>Retrieve the current value of one or more
 341         object properties. Takes a service name, object path,
 342         interface name and property name. Multiple properties may be
 343         specified at once, in which case their values will be shown one
 344         after the other, separated by newlines. The output is, by
 345         default, in terse format. Use <option>--verbose</option> for a
 346         more elaborate output format.</para></listitem>
 347       </varlistentry>
 348
 349       <varlistentry>
 350         <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>
 351
 352         <listitem><para>Set the current value of an object
 353         property. Takes a service name, object path, interface name,
 354         property name, property signature, followed by a list of
 355         parameters formatted as strings.</para></listitem>
 356       </varlistentry>
 357
 358       <varlistentry>
 359         <term><command>help</command></term>
 360
 361         <listitem><para>Show command syntax help.</para></listitem>
 362       </varlistentry>
 363     </variablelist>
 364   </refsect1>
 365
 366   <refsect1>
 367     <title>Parameter Formatting</title>
 368
 369     <para>The <command>call</command> and
 370     <command>set-property</command> commands take a signature string
 371     followed by a list of parameters formatted as string (for details
 372     on D-Bus signature strings, see the <ulink
 373     url="http://dbus.freedesktop.org/doc/dbus-specification.html#type-system">Type
 374     system chapter of the D-Bus specification</ulink>). For simple
 375     types, each parameter following the signature should simply be the
 376     parameter's value formatted as string. Positive boolean values may
 377     be formatted as <literal>true</literal>, <literal>yes</literal>,
 378     <literal>on</literal>, or <literal>1</literal>; negative boolean
 379     values may be specified as <literal>false</literal>,
 380     <literal>no</literal>, <literal>off</literal>, or
 381     <literal>0</literal>. For arrays, a numeric argument for the
 382     number of entries followed by the entries shall be specified. For
 383     variants, the signature of the contents shall be specified,
 384     followed by the contents. For dictionaries and structs, the
 385     contents of them shall be directly specified.</para>
 386
 387     <para>For example,
 388     <programlisting>s jawoll</programlisting> is the formatting
 389     of a single string <literal>jawoll</literal>.</para>
 390
 391     <para>
 392     <programlisting>as 3 hello world foobar</programlisting>
 393     is the formatting of a string array with three entries,
 394     <literal>hello</literal>, <literal>world</literal> and
 395     <literal>foobar</literal>.</para>
 396
 397     <para>
 398     <programlisting>a{sv} 3 One s Eins Two u 2 Yes b true</programlisting>
 399     is the formatting of a dictionary
 400     array that maps strings to variants, consisting of three
 401     entries. The string <literal>One</literal> is assigned the
 402     string <literal>Eins</literal>. The string
 403     <literal>Two</literal> is assigned the 32-bit unsigned
 404     integer 2. The string <literal>Yes</literal> is assigned a
 405     positive boolean.</para>
 406
 407     <para>Note that the <command>call</command>,
 408     <command>get-property</command>, <command>introspect</command>
 409     commands will also generate output in this format for the returned
 410     data. Since this format is sometimes too terse to be easily
 411     understood, the <command>call</command> and
 412     <command>get-property</command> commands may generate a more
 413     verbose, multi-line output when passed the
 414     <option>--verbose</option> option.</para>
 415   </refsect1>
 416
 417   <refsect1>
 418     <title>Examples</title>
 419
 420     <example>
 421       <title>Write and Read a Property</title>
 422
 423       <para>The following two commands first write a property and then
 424       read it back. The property is found on the
 425       <literal>/org/freedesktop/systemd1</literal> object of the
 426       <literal>org.freedesktop.systemd1</literal> service. The name of
 427       the property is <literal>LogLevel</literal> on the
 428       <literal>org.freedesktop.systemd1.Manager</literal>
 429       interface. The property contains a single string:</para>
 430
 431       <programlisting># busctl set-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel s debug
 432 # busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager LogLevel
 433 s "debug"</programlisting>
 434
 435     </example>
 436
 437     <example>
 438       <title>Terse and Verbose Output</title>
 439
 440       <para>The following two commands read a property that contains
 441       an array of strings, and first show it in terse format, followed
 442       by verbose format:</para>
 443
 444       <programlisting>$ busctl get-property org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 445 as 2 "LANG=en_US.UTF-8" "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin"
 446 $ busctl get-property --verbose org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager Environment
 447 ARRAY "s" {
 448         STRING "LANG=en_US.UTF-8";
 449         STRING "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin";
 450 };</programlisting>
 451     </example>
 452
 453     <example>
 454       <title>Invoking a Method</title>
 455
 456       <para>The following command invokes the
 457       <literal>StartUnit</literal> method on the
 458       <literal>org.freedesktop.systemd1.Manager</literal>
 459       interface of the
 460       <literal>/org/freedesktop/systemd1</literal> object
 461       of the <literal>org.freedesktop.systemd1</literal>
 462       service, and passes it two strings
 463       <literal>cups.service</literal> and
 464       <literal>replace</literal>. As a result of the method
 465       call, a single object path parameter is received and
 466       shown:</para>
 467
 468       <programlisting># busctl call org.freedesktop.systemd1 /org/freedesktop/systemd1 org.freedesktop.systemd1.Manager StartUnit ss "cups.service" "replace"
 469 o "/org/freedesktop/systemd1/job/42684"</programlisting>
 470     </example>
 471   </refsect1>
 472
 473   <refsect1>
 474     <title>See Also</title>
 475
 476     <para>
 477       <citerefentry project='dbus'><refentrytitle>dbus-daemon</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 478       <ulink url="https://www.freedesktop.org/wiki/Software/dbus">D-Bus</ulink>,
 479       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 480       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 481       <citerefentry><refentrytitle>machinectl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 482       <citerefentry project='die-net'><refentrytitle>wireshark</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 483     </para>
 484   </refsect1>
 485 </refentry>