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