man/sd_bus_creds_get_pid.xml

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  26
  27 <refentry id="sd_bus_creds_get_pid">
  28
  29   <refentryinfo>
  30     <title>sd_bus_creds_get_pid</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>sd_bus_creds_get_pid</refentrytitle>
  45     <manvolnum>3</manvolnum>
  46   </refmeta>
  47
  48   <refnamediv>
  49     <refname>sd_bus_creds_get_pid</refname>
  50     <refname>sd_bus_creds_get_ppid</refname>
  51     <refname>sd_bus_creds_get_tid</refname>
  52     <refname>sd_bus_creds_get_uid</refname>
  53     <refname>sd_bus_creds_get_euid</refname>
  54     <refname>sd_bus_creds_get_suid</refname>
  55     <refname>sd_bus_creds_get_fsuid</refname>
  56     <refname>sd_bus_creds_get_gid</refname>
  57     <refname>sd_bus_creds_get_egid</refname>
  58     <refname>sd_bus_creds_get_sgid</refname>
  59     <refname>sd_bus_creds_get_fsgid</refname>
  60     <refname>sd_bus_creds_get_supplementary_gids</refname>
  61     <refname>sd_bus_creds_get_comm</refname>
  62     <refname>sd_bus_creds_get_tid_comm</refname>
  63     <refname>sd_bus_creds_get_exe</refname>
  64     <refname>sd_bus_creds_get_cmdline</refname>
  65     <refname>sd_bus_creds_get_cgroup</refname>
  66     <refname>sd_bus_creds_get_unit</refname>
  67     <refname>sd_bus_creds_get_user_unit</refname>
  68     <refname>sd_bus_creds_get_slice</refname>
  69     <refname>sd_bus_creds_get_session</refname>
  70     <refname>sd_bus_creds_get_owner_uid</refname>
  71     <refname>sd_bus_creds_has_effective_cap</refname>
  72     <refname>sd_bus_creds_has_permitted_cap</refname>
  73     <refname>sd_bus_creds_has_inheritable_cap</refname>
  74     <refname>sd_bus_creds_has_bounding_cap</refname>
  75     <refname>sd_bus_creds_get_selinux_context</refname>
  76     <refname>sd_bus_creds_get_audit_session_id</refname>
  77     <refname>sd_bus_creds_get_audit_login_uid</refname>
  78     <refname>sd_bus_creds_get_tty</refname>
  79     <refname>sd_bus_creds_get_unique_name</refname>
  80     <refname>sd_bus_creds_get_well_known_names</refname>
  81     <refname>sd_bus_creds_get_description</refname>
  82
  83     <refpurpose>Retrieve fields from a credentials object</refpurpose>
  84   </refnamediv>
  85
  86   <refsynopsisdiv>
  87     <funcsynopsis>
  88       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  89
  90       <funcprototype>
  91         <funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>
  92         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  93         <paramdef>pid_t *<parameter>pid</parameter></paramdef>
  94       </funcprototype>
  95
  96       <funcprototype>
  97         <funcdef>int <function>sd_bus_creds_get_ppid</function></funcdef>
  98         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  99         <paramdef>pid_t *<parameter>ppid</parameter></paramdef>
 100       </funcprototype>
 101
 102       <funcprototype>
 103         <funcdef>int <function>sd_bus_creds_get_tid</function></funcdef>
 104         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 105         <paramdef>pid_t *<parameter>tid</parameter></paramdef>
 106       </funcprototype>
 107
 108       <funcprototype>
 109         <funcdef>int <function>sd_bus_creds_get_uid</function></funcdef>
 110         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 111         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 112       </funcprototype>
 113
 114       <funcprototype>
 115         <funcdef>int <function>sd_bus_creds_get_euid</function></funcdef>
 116         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 117         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 118       </funcprototype>
 119
 120       <funcprototype>
 121         <funcdef>int <function>sd_bus_creds_get_suid</function></funcdef>
 122         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 123         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 124       </funcprototype>
 125
 126       <funcprototype>
 127         <funcdef>int <function>sd_bus_creds_get_fsuid</function></funcdef>
 128         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 129         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 130       </funcprototype>
 131
 132       <funcprototype>
 133         <funcdef>int <function>sd_bus_creds_get_gid</function></funcdef>
 134         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 135         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 136       </funcprototype>
 137
 138       <funcprototype>
 139         <funcdef>int <function>sd_bus_creds_get_egid</function></funcdef>
 140         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 141         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 142       </funcprototype>
 143
 144       <funcprototype>
 145         <funcdef>int <function>sd_bus_creds_get_sgid</function></funcdef>
 146         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 147         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 148       </funcprototype>
 149
 150       <funcprototype>
 151         <funcdef>int <function>sd_bus_creds_get_fsgid</function></funcdef>
 152         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 153         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 154       </funcprototype>
 155
 156       <funcprototype>
 157         <funcdef>int <function>sd_bus_creds_get_supplementary_gids</function></funcdef>
 158         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 159         <paramdef>const gid_t **<parameter>gids</parameter></paramdef>
 160       </funcprototype>
 161
 162       <funcprototype>
 163         <funcdef>int <function>sd_bus_creds_get_comm</function></funcdef>
 164         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 165         <paramdef>const char **<parameter>comm</parameter></paramdef>
 166       </funcprototype>
 167
 168       <funcprototype>
 169         <funcdef>int <function>sd_bus_creds_get_tid_comm</function></funcdef>
 170         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 171         <paramdef>const char **<parameter>comm</parameter></paramdef>
 172       </funcprototype>
 173
 174       <funcprototype>
 175         <funcdef>int <function>sd_bus_creds_get_exe</function></funcdef>
 176         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 177         <paramdef>const char **<parameter>exe</parameter></paramdef>
 178       </funcprototype>
 179
 180       <funcprototype>
 181         <funcdef>int <function>sd_bus_creds_get_cmdline</function></funcdef>
 182         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 183         <paramdef>char ***<parameter>cmdline</parameter></paramdef>
 184       </funcprototype>
 185
 186       <funcprototype>
 187         <funcdef>int <function>sd_bus_creds_get_cgroup</function></funcdef>
 188         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 189         <paramdef>const char **<parameter>cgroup</parameter></paramdef>
 190       </funcprototype>
 191
 192       <funcprototype>
 193         <funcdef>int <function>sd_bus_creds_get_unit</function></funcdef>
 194         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 195         <paramdef>const char **<parameter>unit</parameter></paramdef>
 196       </funcprototype>
 197
 198       <funcprototype>
 199         <funcdef>int <function>sd_bus_creds_get_user_unit</function></funcdef>
 200         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 201         <paramdef>const char **<parameter>unit</parameter></paramdef>
 202       </funcprototype>
 203
 204       <funcprototype>
 205         <funcdef>int <function>sd_bus_creds_get_slice</function></funcdef>
 206         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 207         <paramdef>const char **<parameter>slice</parameter></paramdef>
 208       </funcprototype>
 209
 210       <funcprototype>
 211         <funcdef>int <function>sd_bus_creds_get_session</function></funcdef>
 212         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 213         <paramdef>const char **<parameter>slice</parameter></paramdef>
 214       </funcprototype>
 215
 216       <funcprototype>
 217         <funcdef>int <function>sd_bus_creds_get_owner_uid</function></funcdef>
 218         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 219         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 220       </funcprototype>
 221
 222       <funcprototype>
 223         <funcdef>int <function>sd_bus_creds_has_effective_cap</function></funcdef>
 224         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 225         <paramdef>int <parameter>capability</parameter></paramdef>
 226       </funcprototype>
 227
 228       <funcprototype>
 229         <funcdef>int <function>sd_bus_creds_has_permitted_cap</function></funcdef>
 230         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 231         <paramdef>int <parameter>capability</parameter></paramdef>
 232       </funcprototype>
 233
 234       <funcprototype>
 235         <funcdef>int <function>sd_bus_creds_has_inheritable_cap</function></funcdef>
 236         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 237         <paramdef>int <parameter>capability</parameter></paramdef>
 238       </funcprototype>
 239
 240       <funcprototype>
 241         <funcdef>int <function>sd_bus_creds_has_bounding_cap</function></funcdef>
 242         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 243         <paramdef>int <parameter>capability</parameter></paramdef>
 244       </funcprototype>
 245
 246       <funcprototype>
 247         <funcdef>int <function>sd_bus_creds_get_selinux_context</function></funcdef>
 248         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 249         <paramdef>const char **<parameter>context</parameter></paramdef>
 250       </funcprototype>
 251
 252       <funcprototype>
 253         <funcdef>int <function>sd_bus_creds_get_audit_session_id</function></funcdef>
 254         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 255         <paramdef>uint32_t *<parameter>sessionid</parameter></paramdef>
 256       </funcprototype>
 257
 258       <funcprototype>
 259         <funcdef>int <function>sd_bus_creds_get_audit_login_uid</function></funcdef>
 260         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 261         <paramdef>uid_t *<parameter>loginuid</parameter></paramdef>
 262       </funcprototype>
 263
 264       <funcprototype>
 265         <funcdef>int <function>sd_bus_creds_get_tty</function></funcdef>
 266         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 267         <paramdef>const char **<parameter>tty</parameter></paramdef>
 268       </funcprototype>
 269
 270       <funcprototype>
 271         <funcdef>int <function>sd_bus_creds_get_unique_name</function></funcdef>
 272         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 273         <paramdef>const char **<parameter>name</parameter></paramdef>
 274       </funcprototype>
 275
 276       <funcprototype>
 277         <funcdef>int <function>sd_bus_creds_get_well_known_names</function></funcdef>
 278         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 279         <paramdef>char ***<parameter>name</parameter></paramdef>
 280       </funcprototype>
 281
 282       <funcprototype>
 283         <funcdef>int <function>sd_bus_creds_get_description</function></funcdef>
 284         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 285         <paramdef>const char **<parameter>name</parameter></paramdef>
 286       </funcprototype>
 287
 288     </funcsynopsis>
 289   </refsynopsisdiv>
 290
 291   <refsect1>
 292     <title>Description</title>
 293
 294     <para>These functions return information from an
 295     <parameter>sd_bus_creds</parameter> credential object. Credential
 296     objects may be created with
 297     <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 298     in which case they describe the credentials of the process
 299     identified by the specified PID, with
 300     <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 301     in which case they describe the credentials of a bus peer
 302     identified by the specified bus name, with
 303     <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 304     in which case they describe the credentials of the creator of a
 305     bus, or with
 306     <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 307     in which case they describe the credentials of the sender of the message.</para>
 308
 309     <para><function>sd_bus_creds_get_pid()</function> will retrieve
 310     the PID (process identifier). Similar,
 311     <function>sd_bus_creds_get_ppid()</function> will retrieve the
 312     parent PID. Note that PID 1 has no parent process, in which case
 313     -ENXIO is returned.</para>
 314
 315     <para><function>sd_bus_creds_get_tid()</function> will retrieve the
 316     TID (thread identifier).</para>
 317
 318     <para><function>sd_bus_creds_get_uid()</function> will retrieve
 319     the numeric UID (user identifier). Similar,
 320     <function>sd_bus_creds_get_euid()</function> returns the effective
 321     UID, <function>sd_bus_creds_get_suid()</function> the saved UID
 322     and <function>sd_bus_creds_get_fsuid()</function> the file system
 323     UID.</para>
 324
 325     <para><function>sd_bus_creds_get_gid()</function> will retrieve the
 326     numeric GID (group identifier). Similar,
 327     <function>sd_bus_creds_get_egid()</function> returns the effective
 328     GID, <function>sd_bus_creds_get_sgid()</function> the saved GID
 329     and <function>sd_bus_creds_get_fsgid()</function> the file system
 330     GID.</para>
 331
 332     <para><function>sd_bus_creds_get_supplementary_gids()</function>
 333     will retrieve the supplementary GIDs list.</para>
 334
 335     <para><function>sd_bus_creds_get_comm()</function> will retrieve the
 336     comm field (truncated name of the executable, as stored in
 337     <filename>/proc/<replaceable>pid</replaceable>/comm</filename>).
 338     </para>
 339
 340     <para><function>sd_bus_creds_get_tid_comm()</function> will retrieve
 341     the comm field of the thread (as stored in
 342     <filename>/proc/<replaceable>pid</replaceable>/task/<replaceable>tid</replaceable>/comm</filename>).
 343     </para>
 344
 345     <para><function>sd_bus_creds_get_exe()</function> will retrieve
 346     the path to the program executable (as stored in the
 347     <filename>/proc/<replaceable>pid</replaceable>/exe</filename>
 348     link, but with <literal> (deleted)</literal> suffix removed). Note
 349     that kernel threads do not have an executable path, in which case
 350     -ENXIO is returned.</para>
 351
 352     <para><function>sd_bus_creds_get_cmdline()</function> will
 353     retrieve an array of command line arguments (as stored in
 354     <filename>/proc/<replaceable>pid</replaceable>/cmdline</filename>). Note
 355     that kernel threads do not have a command line, in which case
 356     -ENXIO is returned.</para>
 357
 358     <para><function>sd_bus_creds_get_cgroup()</function> will retrieve
 359     the cgroup path. See <ulink
 360     url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.
 361     </para>
 362
 363     <para><function>sd_bus_creds_get_unit()</function> will retrieve
 364     the systemd unit name (in the system instance of systemd) that the
 365     process is part of. See
 366     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 367     processes that are not part of a unit returns -ENXIO.
 368     </para>
 369
 370     <para><function>sd_bus_creds_get_user_unit()</function> will
 371     retrieve the systemd unit name (in the user instance of systemd)
 372     that the process is part of. See
 373     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 374     processes that are not part of a user unit returns -ENXIO.
 375     </para>
 376
 377     <para><function>sd_bus_creds_get_slice()</function> will retrieve
 378     the systemd slice (a unit in the system instance of systemd) that
 379     the process is part of. See
 380     <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 381     </para>
 382
 383     <para><function>sd_bus_creds_get_session()</function> will
 384     retrieve the logind session that the process is part of. See
 385     <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. For
 386     processes that are not part of a session returns -ENXIO.
 387     </para>
 388
 389     <para><function>sd_bus_creds_get_owner_uid()</function> will
 390     retrieve the numeric UID (user identifier) of the user who owns
 391     the session that the process is part of. See
 392     <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 393     For processes that are not part of a session returns -ENXIO.
 394     </para>
 395
 396     <para><function>sd_bus_creds_has_effective_cap()</function> will
 397     check whether the capability specified by
 398     <parameter>capability</parameter> was set in the effective
 399     capabilities mask. A positive return value means that is was
 400     set, zero means that it was not set, and a negative return
 401     value signifies an error. See
 402     <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 403     and <varname>Capabilities=</varname> and
 404     <varname>CapabilityBoundingSet=</varname> settings in
 405     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 406     </para>
 407
 408     <para><function>sd_bus_creds_has_permitted_cap()</function> is
 409     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 410     but will check the permitted capabilities mask.</para>
 411
 412     <para><function>sd_bus_creds_has_inheritable_cap()</function> is
 413     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 414     but will check the inheritable capabilities mask.</para>
 415
 416     <para><function>sd_bus_creds_has_bounding_cap()</function> is
 417     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 418     but will check the bounding capabilities mask.</para>
 419
 420     <para><function>sd_bus_creds_get_selinux_context()</function> will
 421     retrieve the SELinux security context (label) of the process.</para>
 422
 423     <para><function>sd_bus_creds_get_audit_session_id()</function>
 424     will retrieve the audit session identifier of the process. Returns
 425     -ENXIO for processes that are not part of an audit session.</para>
 426
 427     <para><function>sd_bus_creds_get_audit_login_uid()</function> will
 428     retrieve the audit user login identifier (the identifier of the
 429     user who is "responsible" for the session). Returns -ENXIO for
 430     processes that are not part of an audit session.</para>
 431
 432     <para><function>sd_bus_creds_get_tty()</function> will retrieve
 433     the controlling TTY. Returns -ENXIO for processes that have no
 434     controlling TTY.</para>
 435
 436     <para><function>sd_bus_creds_get_unique_name()</function> will
 437     retrieve the D-Bus unique name. See <ulink
 438     url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
 439     D-Bus specification</ulink>.</para>
 440
 441     <para><function>sd_bus_creds_get_well_known_names()</function> will
 442     retrieve the set of D-Bus well-known names. See <ulink
 443     url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
 444     D-Bus specification</ulink>.</para>
 445
 446     <para><function>sd_bus_creds_get_description()</function> will
 447     retrieve a descriptive name of the bus connection of the
 448     peer. This name is useful to discern multiple bus connections by
 449     the same peer, and may be altered by the peer with the
 450     <citerefentry><refentrytitle>sd_bus_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 451     call.</para>
 452
 453     <para>All functions that take a <parameter>const
 454     char**</parameter> parameter will store the answer there as an
 455     address of a NUL-terminated string. It will be valid as long as
 456     <parameter>c</parameter> remains valid, and should not be freed or
 457     modified by the caller.</para>
 458
 459     <para>All functions that take a <parameter>char***</parameter>
 460     parameter will store the answer there as an address of a an array
 461     of strings. Each individual string is NUL-terminated, and the
 462     array is NULL-terminated as a whole. It will be valid as long as
 463     <parameter>c</parameter> remains valid, and should not be freed or
 464     modified by the caller.</para>
 465   </refsect1>
 466
 467   <refsect1>
 468     <title>Return Value</title>
 469
 470     <para>On success, these calls return 0 or a positive integer. On
 471     failure, these calls return a negative errno-style error code.
 472     </para>
 473   </refsect1>
 474
 475   <refsect1>
 476     <title>Errors</title>
 477
 478     <para>Returned errors may indicate the following problems:</para>
 479
 480     <variablelist>
 481       <varlistentry>
 482         <term><constant>-ENODATA</constant></term>
 483
 484         <listitem><para>Given field is not available in the
 485         credentials object <parameter>c</parameter>.</para>
 486         </listitem>
 487       </varlistentry>
 488
 489       <varlistentry>
 490         <term><constant>-ENXIO</constant></term>
 491
 492         <listitem><para>Given field is not specified for the described
 493         process or peer. This will be returned by
 494         <function>sd_bus_get_unit()</function>,
 495         <function>sd_bus_get_user_unit()</function>,
 496         <function>sd_bus_get_slice()</function>,
 497         <function>sd_bus_get_session()</function>, and
 498         <function>sd_bus_get_owner_uid()</function> if the process is
 499         not part of a systemd system unit, systemd user unit, systemd
 500         slice, or logind session. It will also be returned by
 501         <function>sd_bus_creds_get_exe()</function> and
 502         <function>sd_bus_creds_get_cmdline()</function> for kernel
 503         threads (since these aren't started from an executable binary
 504         or have a command line),
 505         <function>sd_bus_creds_get_audit_session_id()</function> and
 506         <function>sd_bus_creds_get_audit_login_uid()</function> when
 507         the process is not part of an audit session, and
 508         <function>sd_bus_creds_get_tty()</function> if the process has
 509         no controlling TTY.
 510         </para>
 511         </listitem>
 512       </varlistentry>
 513
 514       <varlistentry>
 515         <term><constant>-EINVAL</constant></term>
 516
 517         <listitem><para>Specified pointer parameter is <constant>NULL</constant>.
 518         </para></listitem>
 519       </varlistentry>
 520
 521       <varlistentry>
 522         <term><constant>-ENOMEM</constant></term>
 523
 524         <listitem><para>Memory allocation failed.</para></listitem>
 525       </varlistentry>
 526     </variablelist>
 527   </refsect1>
 528
 529   <refsect1>
 530     <title>Notes</title>
 531
 532     <para><function>sd_bus_open_user()</function> and other functions
 533     described here are available as a shared library, which can be
 534     compiled and linked to with the
 535     <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 536     file.</para>
 537   </refsect1>
 538
 539   <refsect1>
 540     <title>See Also</title>
 541
 542     <para>
 543       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 544       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 545       <citerefentry><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 546       <citerefentry><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 547       <citerefentry project='man-pages'><refentrytitle>credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 548       <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 549       <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 550       <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 551     </para>
 552   </refsect1>
 553
 554 </refentry>