man/busctl.xml

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