man/sd_bus_creds_get_pid.xml

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  23
  24 <refentry id="sd_bus_creds_get_pid">
  25
  26   <refentryinfo>
  27     <title>sd_bus_creds_get_pid</title>
  28     <productname>systemd</productname>
  29
  30     <authorgroup>
  31       <author>
  32         <contrib>A monkey with a typewriter</contrib>
  33         <firstname>Zbigniew</firstname>
  34         <surname>Jędrzejewski-Szmek</surname>
  35         <email>zbyszek@in.waw.pl</email>
  36       </author>
  37     </authorgroup>
  38   </refentryinfo>
  39
  40   <refmeta>
  41     <refentrytitle>sd_bus_creds_get_pid</refentrytitle>
  42     <manvolnum>3</manvolnum>
  43   </refmeta>
  44
  45   <refnamediv>
  46     <refname>sd_bus_creds_get_pid</refname>
  47     <refname>sd_bus_creds_get_ppid</refname>
  48     <refname>sd_bus_creds_get_tid</refname>
  49     <refname>sd_bus_creds_get_uid</refname>
  50     <refname>sd_bus_creds_get_euid</refname>
  51     <refname>sd_bus_creds_get_suid</refname>
  52     <refname>sd_bus_creds_get_fsuid</refname>
  53     <refname>sd_bus_creds_get_gid</refname>
  54     <refname>sd_bus_creds_get_egid</refname>
  55     <refname>sd_bus_creds_get_sgid</refname>
  56     <refname>sd_bus_creds_get_fsgid</refname>
  57     <refname>sd_bus_creds_get_supplementary_gids</refname>
  58     <refname>sd_bus_creds_get_comm</refname>
  59     <refname>sd_bus_creds_get_tid_comm</refname>
  60     <refname>sd_bus_creds_get_exe</refname>
  61     <refname>sd_bus_creds_get_cmdline</refname>
  62     <refname>sd_bus_creds_get_cgroup</refname>
  63     <refname>sd_bus_creds_get_unit</refname>
  64     <refname>sd_bus_creds_get_user_unit</refname>
  65     <refname>sd_bus_creds_get_slice</refname>
  66     <refname>sd_bus_creds_get_session</refname>
  67     <refname>sd_bus_creds_get_owner_uid</refname>
  68     <refname>sd_bus_creds_has_effective_cap</refname>
  69     <refname>sd_bus_creds_has_permitted_cap</refname>
  70     <refname>sd_bus_creds_has_inheritable_cap</refname>
  71     <refname>sd_bus_creds_has_bounding_cap</refname>
  72     <refname>sd_bus_creds_get_selinux_context</refname>
  73     <refname>sd_bus_creds_get_audit_session_id</refname>
  74     <refname>sd_bus_creds_get_audit_login_uid</refname>
  75     <refname>sd_bus_creds_get_tty</refname>
  76     <refname>sd_bus_creds_get_unique_name</refname>
  77     <refname>sd_bus_creds_get_well_known_names</refname>
  78     <refname>sd_bus_creds_get_description</refname>
  79
  80     <refpurpose>Retrieve fields from a credentials object</refpurpose>
  81   </refnamediv>
  82
  83   <refsynopsisdiv>
  84     <funcsynopsis>
  85       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  86
  87       <funcprototype>
  88         <funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>
  89         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  90         <paramdef>pid_t *<parameter>pid</parameter></paramdef>
  91       </funcprototype>
  92
  93       <funcprototype>
  94         <funcdef>int <function>sd_bus_creds_get_ppid</function></funcdef>
  95         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  96         <paramdef>pid_t *<parameter>ppid</parameter></paramdef>
  97       </funcprototype>
  98
  99       <funcprototype>
 100         <funcdef>int <function>sd_bus_creds_get_tid</function></funcdef>
 101         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 102         <paramdef>pid_t *<parameter>tid</parameter></paramdef>
 103       </funcprototype>
 104
 105       <funcprototype>
 106         <funcdef>int <function>sd_bus_creds_get_uid</function></funcdef>
 107         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 108         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 109       </funcprototype>
 110
 111       <funcprototype>
 112         <funcdef>int <function>sd_bus_creds_get_euid</function></funcdef>
 113         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 114         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 115       </funcprototype>
 116
 117       <funcprototype>
 118         <funcdef>int <function>sd_bus_creds_get_suid</function></funcdef>
 119         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 120         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 121       </funcprototype>
 122
 123       <funcprototype>
 124         <funcdef>int <function>sd_bus_creds_get_fsuid</function></funcdef>
 125         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 126         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 127       </funcprototype>
 128
 129       <funcprototype>
 130         <funcdef>int <function>sd_bus_creds_get_gid</function></funcdef>
 131         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 132         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 133       </funcprototype>
 134
 135       <funcprototype>
 136         <funcdef>int <function>sd_bus_creds_get_egid</function></funcdef>
 137         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 138         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 139       </funcprototype>
 140
 141       <funcprototype>
 142         <funcdef>int <function>sd_bus_creds_get_sgid</function></funcdef>
 143         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 144         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 145       </funcprototype>
 146
 147       <funcprototype>
 148         <funcdef>int <function>sd_bus_creds_get_fsgid</function></funcdef>
 149         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 150         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 151       </funcprototype>
 152
 153       <funcprototype>
 154         <funcdef>int <function>sd_bus_creds_get_supplementary_gids</function></funcdef>
 155         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 156         <paramdef>const gid_t **<parameter>gids</parameter></paramdef>
 157       </funcprototype>
 158
 159       <funcprototype>
 160         <funcdef>int <function>sd_bus_creds_get_comm</function></funcdef>
 161         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 162         <paramdef>const char **<parameter>comm</parameter></paramdef>
 163       </funcprototype>
 164
 165       <funcprototype>
 166         <funcdef>int <function>sd_bus_creds_get_tid_comm</function></funcdef>
 167         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 168         <paramdef>const char **<parameter>comm</parameter></paramdef>
 169       </funcprototype>
 170
 171       <funcprototype>
 172         <funcdef>int <function>sd_bus_creds_get_exe</function></funcdef>
 173         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 174         <paramdef>const char **<parameter>exe</parameter></paramdef>
 175       </funcprototype>
 176
 177       <funcprototype>
 178         <funcdef>int <function>sd_bus_creds_get_cmdline</function></funcdef>
 179         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 180         <paramdef>char ***<parameter>cmdline</parameter></paramdef>
 181       </funcprototype>
 182
 183       <funcprototype>
 184         <funcdef>int <function>sd_bus_creds_get_cgroup</function></funcdef>
 185         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 186         <paramdef>const char **<parameter>cgroup</parameter></paramdef>
 187       </funcprototype>
 188
 189       <funcprototype>
 190         <funcdef>int <function>sd_bus_creds_get_unit</function></funcdef>
 191         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 192         <paramdef>const char **<parameter>unit</parameter></paramdef>
 193       </funcprototype>
 194
 195       <funcprototype>
 196         <funcdef>int <function>sd_bus_creds_get_user_unit</function></funcdef>
 197         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 198         <paramdef>const char **<parameter>unit</parameter></paramdef>
 199       </funcprototype>
 200
 201       <funcprototype>
 202         <funcdef>int <function>sd_bus_creds_get_slice</function></funcdef>
 203         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 204         <paramdef>const char **<parameter>slice</parameter></paramdef>
 205       </funcprototype>
 206
 207       <funcprototype>
 208         <funcdef>int <function>sd_bus_creds_get_session</function></funcdef>
 209         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 210         <paramdef>const char **<parameter>slice</parameter></paramdef>
 211       </funcprototype>
 212
 213       <funcprototype>
 214         <funcdef>int <function>sd_bus_creds_get_owner_uid</function></funcdef>
 215         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 216         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 217       </funcprototype>
 218
 219       <funcprototype>
 220         <funcdef>int <function>sd_bus_creds_has_effective_cap</function></funcdef>
 221         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 222         <paramdef>int <parameter>capability</parameter></paramdef>
 223       </funcprototype>
 224
 225       <funcprototype>
 226         <funcdef>int <function>sd_bus_creds_has_permitted_cap</function></funcdef>
 227         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 228         <paramdef>int <parameter>capability</parameter></paramdef>
 229       </funcprototype>
 230
 231       <funcprototype>
 232         <funcdef>int <function>sd_bus_creds_has_inheritable_cap</function></funcdef>
 233         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 234         <paramdef>int <parameter>capability</parameter></paramdef>
 235       </funcprototype>
 236
 237       <funcprototype>
 238         <funcdef>int <function>sd_bus_creds_has_bounding_cap</function></funcdef>
 239         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 240         <paramdef>int <parameter>capability</parameter></paramdef>
 241       </funcprototype>
 242
 243       <funcprototype>
 244         <funcdef>int <function>sd_bus_creds_get_selinux_context</function></funcdef>
 245         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 246         <paramdef>const char **<parameter>context</parameter></paramdef>
 247       </funcprototype>
 248
 249       <funcprototype>
 250         <funcdef>int <function>sd_bus_creds_get_audit_session_id</function></funcdef>
 251         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 252         <paramdef>uint32_t *<parameter>sessionid</parameter></paramdef>
 253       </funcprototype>
 254
 255       <funcprototype>
 256         <funcdef>int <function>sd_bus_creds_get_audit_login_uid</function></funcdef>
 257         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 258         <paramdef>uid_t *<parameter>loginuid</parameter></paramdef>
 259       </funcprototype>
 260
 261       <funcprototype>
 262         <funcdef>int <function>sd_bus_creds_get_tty</function></funcdef>
 263         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 264         <paramdef>const char **<parameter>tty</parameter></paramdef>
 265       </funcprototype>
 266
 267       <funcprototype>
 268         <funcdef>int <function>sd_bus_creds_get_unique_name</function></funcdef>
 269         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 270         <paramdef>const char **<parameter>name</parameter></paramdef>
 271       </funcprototype>
 272
 273       <funcprototype>
 274         <funcdef>int <function>sd_bus_creds_get_well_known_names</function></funcdef>
 275         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 276         <paramdef>char ***<parameter>name</parameter></paramdef>
 277       </funcprototype>
 278
 279       <funcprototype>
 280         <funcdef>int <function>sd_bus_creds_get_description</function></funcdef>
 281         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 282         <paramdef>const char **<parameter>name</parameter></paramdef>
 283       </funcprototype>
 284
 285     </funcsynopsis>
 286   </refsynopsisdiv>
 287
 288   <refsect1>
 289     <title>Description</title>
 290
 291     <para>These functions return information from an
 292     <parameter>sd_bus_creds</parameter> credential object. Credential
 293     objects may be created with
 294     <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 295     in which case they describe the credentials of the process
 296     identified by the specified PID, with
 297     <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 298     in which case they describe the credentials of a bus peer
 299     identified by the specified bus name, with
 300     <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 301     in which case they describe the credentials of the creator of a
 302     bus, or with
 303     <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 304     in which case they describe the credentials of the sender of the message.</para>
 305
 306     <para><function>sd_bus_creds_get_pid()</function> will retrieve
 307     the PID (process identifier). Similar,
 308     <function>sd_bus_creds_get_ppid()</function> will retrieve the
 309     parent PID. Note that PID 1 has no parent process, in which case
 310     -ENXIO is returned.</para>
 311
 312     <para><function>sd_bus_creds_get_tid()</function> will retrieve the
 313     TID (thread identifier).</para>
 314
 315     <para><function>sd_bus_creds_get_uid()</function> will retrieve
 316     the numeric UID (user identifier). Similar,
 317     <function>sd_bus_creds_get_euid()</function> returns the effective
 318     UID, <function>sd_bus_creds_get_suid()</function> the saved UID
 319     and <function>sd_bus_creds_get_fsuid()</function> the file system
 320     UID.</para>
 321
 322     <para><function>sd_bus_creds_get_gid()</function> will retrieve the
 323     numeric GID (group identifier). Similar,
 324     <function>sd_bus_creds_get_egid()</function> returns the effective
 325     GID, <function>sd_bus_creds_get_sgid()</function> the saved GID
 326     and <function>sd_bus_creds_get_fsgid()</function> the file system
 327     GID.</para>
 328
 329     <para><function>sd_bus_creds_get_supplementary_gids()</function>
 330     will retrieve the supplementary GIDs list.</para>
 331
 332     <para><function>sd_bus_creds_get_comm()</function> will retrieve the
 333     comm field (truncated name of the executable, as stored in
 334     <filename>/proc/<replaceable>pid</replaceable>/comm</filename>).
 335     </para>
 336
 337     <para><function>sd_bus_creds_get_tid_comm()</function> will retrieve
 338     the comm field of the thread (as stored in
 339     <filename>/proc/<replaceable>pid</replaceable>/task/<replaceable>tid</replaceable>/comm</filename>).
 340     </para>
 341
 342     <para><function>sd_bus_creds_get_exe()</function> will retrieve
 343     the path to the program executable (as stored in the
 344     <filename>/proc/<replaceable>pid</replaceable>/exe</filename>
 345     link, but with <literal> (deleted)</literal> suffix removed). Note
 346     that kernel threads do not have an executable path, in which case
 347     -ENXIO is returned.</para>
 348
 349     <para><function>sd_bus_creds_get_cmdline()</function> will
 350     retrieve an array of command line arguments (as stored in
 351     <filename>/proc/<replaceable>pid</replaceable>/cmdline</filename>). Note
 352     that kernel threads do not have a command line, in which case
 353     -ENXIO is returned.</para>
 354
 355     <para><function>sd_bus_creds_get_cgroup()</function> will retrieve
 356     the cgroup path. See <ulink
 357     url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.
 358     </para>
 359
 360     <para><function>sd_bus_creds_get_unit()</function> will retrieve
 361     the systemd unit name (in the system instance of systemd) that the
 362     process is part of. See
 363     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 364     processes that are not part of a unit returns -ENXIO.
 365     </para>
 366
 367     <para><function>sd_bus_creds_get_user_unit()</function> will
 368     retrieve the systemd unit name (in the user instance of systemd)
 369     that the process is part of. See
 370     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 371     processes that are not part of a user unit returns -ENXIO.
 372     </para>
 373
 374     <para><function>sd_bus_creds_get_slice()</function> will retrieve
 375     the systemd slice (a unit in the system instance of systemd) that
 376     the process is part of. See
 377     <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 378     </para>
 379
 380     <para><function>sd_bus_creds_get_session()</function> will
 381     retrieve the logind session that the process is part of. See
 382     <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. For
 383     processes that are not part of a session returns -ENXIO.
 384     </para>
 385
 386     <para><function>sd_bus_creds_get_owner_uid()</function> will
 387     retrieve the numeric UID (user identifier) of the user who owns
 388     the session that the process is part of. See
 389     <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 390     For processes that are not part of a session returns -ENXIO.
 391     </para>
 392
 393     <para><function>sd_bus_creds_has_effective_cap()</function> will
 394     check whether the capability specified by
 395     <parameter>capability</parameter> was set in the effective
 396     capabilities mask. A positive return value means that is was
 397     set, zero means that it was not set, and a negative return
 398     value signifies an error. See
 399     <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 400     and <varname>Capabilities=</varname> and
 401     <varname>CapabilityBoundingSet=</varname> settings in
 402     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 403     </para>
 404
 405     <para><function>sd_bus_creds_has_permitted_cap()</function> is
 406     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 407     but will check the permitted capabilities mask.</para>
 408
 409     <para><function>sd_bus_creds_has_inheritable_cap()</function> is
 410     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 411     but will check the inheritable capabilities mask.</para>
 412
 413     <para><function>sd_bus_creds_has_bounding_cap()</function> is
 414     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 415     but will check the bounding capabilities mask.</para>
 416
 417     <para><function>sd_bus_creds_get_selinux_context()</function> will
 418     retrieve the SELinux security context (label) of the process.</para>
 419
 420     <para><function>sd_bus_creds_get_audit_session_id()</function>
 421     will retrieve the audit session identifier of the process. Returns
 422     -ENXIO for processes that are not part of an audit session.</para>
 423
 424     <para><function>sd_bus_creds_get_audit_login_uid()</function> will
 425     retrieve the audit user login identifier (the identifier of the
 426     user who is "responsible" for the session). Returns -ENXIO for
 427     processes that are not part of an audit session.</para>
 428
 429     <para><function>sd_bus_creds_get_tty()</function> will retrieve
 430     the controlling TTY. Returns -ENXIO for processes that have no
 431     controlling TTY.</para>
 432
 433     <para><function>sd_bus_creds_get_unique_name()</function> will
 434     retrieve the D-Bus unique name. See <ulink
 435     url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
 436     D-Bus specification</ulink>.</para>
 437
 438     <para><function>sd_bus_creds_get_well_known_names()</function> will
 439     retrieve the set of D-Bus well-known names. See <ulink
 440     url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
 441     D-Bus specification</ulink>.</para>
 442
 443     <para><function>sd_bus_creds_get_description()</function> will
 444     retrieve a descriptive name of the bus connection of the
 445     peer. This name is useful to discern multiple bus connections by
 446     the same peer, and may be altered by the peer with the
 447     <citerefentry><refentrytitle>sd_bus_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 448     call.</para>
 449
 450     <para>All functions that take a <parameter>const
 451     char**</parameter> parameter will store the answer there as an
 452     address of a NUL-terminated string. It will be valid as long as
 453     <parameter>c</parameter> remains valid, and should not be freed or
 454     modified by the caller.</para>
 455
 456     <para>All functions that take a <parameter>char***</parameter>
 457     parameter will store the answer there as an address of a an array
 458     of strings. Each individual string is NUL-terminated, and the
 459     array is NULL-terminated as a whole. It will be valid as long as
 460     <parameter>c</parameter> remains valid, and should not be freed or
 461     modified by the caller.</para>
 462   </refsect1>
 463
 464   <refsect1>
 465     <title>Return Value</title>
 466
 467     <para>On success, these calls return 0 or a positive integer. On
 468     failure, these calls return a negative errno-style error code.
 469     </para>
 470   </refsect1>
 471
 472   <refsect1>
 473     <title>Errors</title>
 474
 475     <para>Returned errors may indicate the following problems:</para>
 476
 477     <variablelist>
 478       <varlistentry>
 479         <term><constant>-ENODATA</constant></term>
 480
 481         <listitem><para>Given field is not available in the
 482         credentials object <parameter>c</parameter>.</para>
 483         </listitem>
 484       </varlistentry>
 485
 486       <varlistentry>
 487         <term><constant>-ENXIO</constant></term>
 488
 489         <listitem><para>Given field is not specified for the described
 490         process or peer. This will be returned by
 491         <function>sd_bus_get_unit()</function>,
 492         <function>sd_bus_get_user_unit()</function>,
 493         <function>sd_bus_get_slice()</function>,
 494         <function>sd_bus_get_session()</function>, and
 495         <function>sd_bus_get_owner_uid()</function> if the process is
 496         not part of a systemd system unit, systemd user unit, systemd
 497         slice, or logind session. It will also be returned by
 498         <function>sd_bus_creds_get_exe()</function> and
 499         <function>sd_bus_creds_get_cmdline()</function> for kernel
 500         threads (since these aren't started from an executable binary
 501         or have a command line),
 502         <function>sd_bus_creds_get_audit_session_id()</function> and
 503         <function>sd_bus_creds_get_audit_login_uid()</function> when
 504         the process is not part of an audit session, and
 505         <function>sd_bus_creds_get_tty()</function> if the process has
 506         no controlling TTY.
 507         </para>
 508         </listitem>
 509       </varlistentry>
 510
 511       <varlistentry>
 512         <term><constant>-EINVAL</constant></term>
 513
 514         <listitem><para>Specified pointer parameter is <constant>NULL</constant>.
 515         </para></listitem>
 516       </varlistentry>
 517
 518       <varlistentry>
 519         <term><constant>-ENOMEM</constant></term>
 520
 521         <listitem><para>Memory allocation failed.</para></listitem>
 522       </varlistentry>
 523     </variablelist>
 524   </refsect1>
 525
 526   <refsect1>
 527     <title>Notes</title>
 528
 529     <para><function>sd_bus_open_user()</function> and other functions
 530     described here are available as a shared library, which can be
 531     compiled and linked to with the
 532     <constant>libsystemd</constant> <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 533     file.</para>
 534   </refsect1>
 535
 536   <refsect1>
 537     <title>See Also</title>
 538
 539     <para>
 540       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 541       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 542       <citerefentry><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 543       <citerefentry><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 544       <citerefentry project='man-pages'><refentrytitle>credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 545       <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 546       <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 547       <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 548     </para>
 549   </refsect1>
 550
 551 </refentry>