man/sd_bus_creds_get_pid.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="sd_bus_creds_get_pid" xmlns:xi="http://www.w3.org/2001/XInclude">
   7
   8   <refentryinfo>
   9     <title>sd_bus_creds_get_pid</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>sd_bus_creds_get_pid</refentrytitle>
  15     <manvolnum>3</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>sd_bus_creds_get_pid</refname>
  20     <refname>sd_bus_creds_get_ppid</refname>
  21     <refname>sd_bus_creds_get_tid</refname>
  22     <refname>sd_bus_creds_get_uid</refname>
  23     <refname>sd_bus_creds_get_euid</refname>
  24     <refname>sd_bus_creds_get_suid</refname>
  25     <refname>sd_bus_creds_get_fsuid</refname>
  26     <refname>sd_bus_creds_get_gid</refname>
  27     <refname>sd_bus_creds_get_egid</refname>
  28     <refname>sd_bus_creds_get_sgid</refname>
  29     <refname>sd_bus_creds_get_fsgid</refname>
  30     <refname>sd_bus_creds_get_supplementary_gids</refname>
  31     <refname>sd_bus_creds_get_comm</refname>
  32     <refname>sd_bus_creds_get_tid_comm</refname>
  33     <refname>sd_bus_creds_get_exe</refname>
  34     <refname>sd_bus_creds_get_cmdline</refname>
  35     <refname>sd_bus_creds_get_cgroup</refname>
  36     <refname>sd_bus_creds_get_unit</refname>
  37     <refname>sd_bus_creds_get_slice</refname>
  38     <refname>sd_bus_creds_get_user_unit</refname>
  39     <refname>sd_bus_creds_get_user_slice</refname>
  40     <refname>sd_bus_creds_get_session</refname>
  41     <refname>sd_bus_creds_get_owner_uid</refname>
  42     <refname>sd_bus_creds_has_effective_cap</refname>
  43     <refname>sd_bus_creds_has_permitted_cap</refname>
  44     <refname>sd_bus_creds_has_inheritable_cap</refname>
  45     <refname>sd_bus_creds_has_bounding_cap</refname>
  46     <refname>sd_bus_creds_get_selinux_context</refname>
  47     <refname>sd_bus_creds_get_audit_session_id</refname>
  48     <refname>sd_bus_creds_get_audit_login_uid</refname>
  49     <refname>sd_bus_creds_get_tty</refname>
  50     <refname>sd_bus_creds_get_unique_name</refname>
  51     <refname>sd_bus_creds_get_well_known_names</refname>
  52     <refname>sd_bus_creds_get_description</refname>
  53
  54     <refpurpose>Retrieve fields from a credentials object</refpurpose>
  55   </refnamediv>
  56
  57   <refsynopsisdiv>
  58     <funcsynopsis>
  59       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  60
  61       <funcprototype>
  62         <funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>
  63         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  64         <paramdef>pid_t *<parameter>pid</parameter></paramdef>
  65       </funcprototype>
  66
  67       <funcprototype>
  68         <funcdef>int <function>sd_bus_creds_get_ppid</function></funcdef>
  69         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  70         <paramdef>pid_t *<parameter>ppid</parameter></paramdef>
  71       </funcprototype>
  72
  73       <funcprototype>
  74         <funcdef>int <function>sd_bus_creds_get_tid</function></funcdef>
  75         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  76         <paramdef>pid_t *<parameter>tid</parameter></paramdef>
  77       </funcprototype>
  78
  79       <funcprototype>
  80         <funcdef>int <function>sd_bus_creds_get_uid</function></funcdef>
  81         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  82         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
  83       </funcprototype>
  84
  85       <funcprototype>
  86         <funcdef>int <function>sd_bus_creds_get_euid</function></funcdef>
  87         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  88         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
  89       </funcprototype>
  90
  91       <funcprototype>
  92         <funcdef>int <function>sd_bus_creds_get_suid</function></funcdef>
  93         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  94         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
  95       </funcprototype>
  96
  97       <funcprototype>
  98         <funcdef>int <function>sd_bus_creds_get_fsuid</function></funcdef>
  99         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 100         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 101       </funcprototype>
 102
 103       <funcprototype>
 104         <funcdef>int <function>sd_bus_creds_get_gid</function></funcdef>
 105         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 106         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 107       </funcprototype>
 108
 109       <funcprototype>
 110         <funcdef>int <function>sd_bus_creds_get_egid</function></funcdef>
 111         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 112         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 113       </funcprototype>
 114
 115       <funcprototype>
 116         <funcdef>int <function>sd_bus_creds_get_sgid</function></funcdef>
 117         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 118         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 119       </funcprototype>
 120
 121       <funcprototype>
 122         <funcdef>int <function>sd_bus_creds_get_fsgid</function></funcdef>
 123         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 124         <paramdef>gid_t *<parameter>gid</parameter></paramdef>
 125       </funcprototype>
 126
 127       <funcprototype>
 128         <funcdef>int <function>sd_bus_creds_get_supplementary_gids</function></funcdef>
 129         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 130         <paramdef>const gid_t **<parameter>gids</parameter></paramdef>
 131       </funcprototype>
 132
 133       <funcprototype>
 134         <funcdef>int <function>sd_bus_creds_get_comm</function></funcdef>
 135         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 136         <paramdef>const char **<parameter>comm</parameter></paramdef>
 137       </funcprototype>
 138
 139       <funcprototype>
 140         <funcdef>int <function>sd_bus_creds_get_tid_comm</function></funcdef>
 141         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 142         <paramdef>const char **<parameter>comm</parameter></paramdef>
 143       </funcprototype>
 144
 145       <funcprototype>
 146         <funcdef>int <function>sd_bus_creds_get_exe</function></funcdef>
 147         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 148         <paramdef>const char **<parameter>exe</parameter></paramdef>
 149       </funcprototype>
 150
 151       <funcprototype>
 152         <funcdef>int <function>sd_bus_creds_get_cmdline</function></funcdef>
 153         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 154         <paramdef>char ***<parameter>cmdline</parameter></paramdef>
 155       </funcprototype>
 156
 157       <funcprototype>
 158         <funcdef>int <function>sd_bus_creds_get_cgroup</function></funcdef>
 159         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 160         <paramdef>const char **<parameter>cgroup</parameter></paramdef>
 161       </funcprototype>
 162
 163       <funcprototype>
 164         <funcdef>int <function>sd_bus_creds_get_unit</function></funcdef>
 165         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 166         <paramdef>const char **<parameter>unit</parameter></paramdef>
 167       </funcprototype>
 168
 169       <funcprototype>
 170         <funcdef>int <function>sd_bus_creds_get_slice</function></funcdef>
 171         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 172         <paramdef>const char **<parameter>slice</parameter></paramdef>
 173       </funcprototype>
 174
 175       <funcprototype>
 176         <funcdef>int <function>sd_bus_creds_get_user_unit</function></funcdef>
 177         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 178         <paramdef>const char **<parameter>unit</parameter></paramdef>
 179       </funcprototype>
 180
 181       <funcprototype>
 182         <funcdef>int <function>sd_bus_creds_get_user_slice</function></funcdef>
 183         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 184         <paramdef>const char **<parameter>slice</parameter></paramdef>
 185       </funcprototype>
 186
 187       <funcprototype>
 188         <funcdef>int <function>sd_bus_creds_get_session</function></funcdef>
 189         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 190         <paramdef>const char **<parameter>slice</parameter></paramdef>
 191       </funcprototype>
 192
 193       <funcprototype>
 194         <funcdef>int <function>sd_bus_creds_get_owner_uid</function></funcdef>
 195         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 196         <paramdef>uid_t *<parameter>uid</parameter></paramdef>
 197       </funcprototype>
 198
 199       <funcprototype>
 200         <funcdef>int <function>sd_bus_creds_has_effective_cap</function></funcdef>
 201         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 202         <paramdef>int <parameter>capability</parameter></paramdef>
 203       </funcprototype>
 204
 205       <funcprototype>
 206         <funcdef>int <function>sd_bus_creds_has_permitted_cap</function></funcdef>
 207         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 208         <paramdef>int <parameter>capability</parameter></paramdef>
 209       </funcprototype>
 210
 211       <funcprototype>
 212         <funcdef>int <function>sd_bus_creds_has_inheritable_cap</function></funcdef>
 213         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 214         <paramdef>int <parameter>capability</parameter></paramdef>
 215       </funcprototype>
 216
 217       <funcprototype>
 218         <funcdef>int <function>sd_bus_creds_has_bounding_cap</function></funcdef>
 219         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 220         <paramdef>int <parameter>capability</parameter></paramdef>
 221       </funcprototype>
 222
 223       <funcprototype>
 224         <funcdef>int <function>sd_bus_creds_get_selinux_context</function></funcdef>
 225         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 226         <paramdef>const char **<parameter>context</parameter></paramdef>
 227       </funcprototype>
 228
 229       <funcprototype>
 230         <funcdef>int <function>sd_bus_creds_get_audit_session_id</function></funcdef>
 231         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 232         <paramdef>uint32_t *<parameter>sessionid</parameter></paramdef>
 233       </funcprototype>
 234
 235       <funcprototype>
 236         <funcdef>int <function>sd_bus_creds_get_audit_login_uid</function></funcdef>
 237         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 238         <paramdef>uid_t *<parameter>loginuid</parameter></paramdef>
 239       </funcprototype>
 240
 241       <funcprototype>
 242         <funcdef>int <function>sd_bus_creds_get_tty</function></funcdef>
 243         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 244         <paramdef>const char **<parameter>tty</parameter></paramdef>
 245       </funcprototype>
 246
 247       <funcprototype>
 248         <funcdef>int <function>sd_bus_creds_get_unique_name</function></funcdef>
 249         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 250         <paramdef>const char **<parameter>name</parameter></paramdef>
 251       </funcprototype>
 252
 253       <funcprototype>
 254         <funcdef>int <function>sd_bus_creds_get_well_known_names</function></funcdef>
 255         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 256         <paramdef>char ***<parameter>name</parameter></paramdef>
 257       </funcprototype>
 258
 259       <funcprototype>
 260         <funcdef>int <function>sd_bus_creds_get_description</function></funcdef>
 261         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
 262         <paramdef>const char **<parameter>name</parameter></paramdef>
 263       </funcprototype>
 264
 265     </funcsynopsis>
 266   </refsynopsisdiv>
 267
 268   <refsect1>
 269     <title>Description</title>
 270
 271     <para>These functions return credential information from an
 272     <parameter>sd_bus_creds</parameter> object. Credential objects may
 273     be created with
 274     <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 275     in which case they describe the credentials of the process
 276     identified by the specified PID, with
 277     <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 278     in which case they describe the credentials of a bus peer
 279     identified by the specified bus name, with
 280     <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 281     in which case they describe the credentials of the creator of a
 282     bus, or with
 283     <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 284     in which case they describe the credentials of the sender of the
 285     message.</para>
 286
 287     <para>Not all credential fields are part of every
 288     <literal>sd_bus_creds</literal> object. Use
 289     <citerefentry><refentrytitle>sd_bus_creds_get_mask</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 290     to determine the mask of fields available.</para>
 291
 292     <para><function>sd_bus_creds_get_pid()</function> will retrieve
 293     the PID (process identifier). Similarly,
 294     <function>sd_bus_creds_get_ppid()</function> will retrieve the
 295     parent PID. Note that PID 1 has no parent process, in which case
 296     -ENXIO is returned.</para>
 297
 298     <para><function>sd_bus_creds_get_tid()</function> will retrieve the
 299     TID (thread identifier).</para>
 300
 301     <para><function>sd_bus_creds_get_uid()</function> will retrieve
 302     the numeric UID (user identifier). Similarly,
 303     <function>sd_bus_creds_get_euid()</function> returns the effective
 304     UID, <function>sd_bus_creds_get_suid()</function> the saved UID
 305     and <function>sd_bus_creds_get_fsuid()</function> the file system
 306     UID.</para>
 307
 308     <para><function>sd_bus_creds_get_gid()</function> will retrieve the
 309     numeric GID (group identifier). Similarly,
 310     <function>sd_bus_creds_get_egid()</function> returns the effective
 311     GID, <function>sd_bus_creds_get_sgid()</function> the saved GID
 312     and <function>sd_bus_creds_get_fsgid()</function> the file system
 313     GID.</para>
 314
 315     <para><function>sd_bus_creds_get_supplementary_gids()</function>
 316     will retrieve the supplementary GIDs list.</para>
 317
 318     <para><function>sd_bus_creds_get_comm()</function> will retrieve the
 319     comm field (truncated name of the executable, as stored in
 320     <filename>/proc/<replaceable>pid</replaceable>/comm</filename>).
 321     </para>
 322
 323     <para><function>sd_bus_creds_get_tid_comm()</function> will retrieve
 324     the comm field of the thread (as stored in
 325     <filename>/proc/<replaceable>pid</replaceable>/task/<replaceable>tid</replaceable>/comm</filename>).
 326     </para>
 327
 328     <para><function>sd_bus_creds_get_exe()</function> will retrieve
 329     the path to the program executable (as stored in the
 330     <filename>/proc/<replaceable>pid</replaceable>/exe</filename>
 331     link, but with the <literal> (deleted)</literal> suffix removed). Note
 332     that kernel threads do not have an executable path, in which case
 333     -ENXIO is returned.</para>
 334
 335     <para><function>sd_bus_creds_get_cmdline()</function> will
 336     retrieve an array of command line arguments (as stored in
 337     <filename>/proc/<replaceable>pid</replaceable>/cmdline</filename>). Note
 338     that kernel threads do not have a command line, in which case
 339     -ENXIO is returned.</para>
 340
 341     <para><function>sd_bus_creds_get_cgroup()</function> will retrieve
 342     the control group path. See <ulink
 343     url="https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt">cgroups.txt</ulink>.
 344     </para>
 345
 346     <para><function>sd_bus_creds_get_unit()</function> will retrieve
 347     the systemd unit name (in the system instance of systemd) that the
 348     process is a part of. See
 349     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 350     processes that are not part of a unit, returns -ENXIO.
 351     </para>
 352
 353     <para><function>sd_bus_creds_get_user_unit()</function> will
 354     retrieve the systemd unit name (in the user instance of systemd)
 355     that the process is a part of. See
 356     <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
 357     processes that are not part of a user unit, returns -ENXIO.
 358     </para>
 359
 360     <para><function>sd_bus_creds_get_slice()</function> will retrieve
 361     the systemd slice (a unit in the system instance of systemd) that
 362     the process is a part of. See
 363     <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Similarly,
 364     <function>sd_bus_creds_get_user_slice()</function> retrieves the
 365     systemd slice of the process, in the user instance of systemd.
 366     </para>
 367
 368     <para><function>sd_bus_creds_get_session()</function> will
 369     retrieve the identifier of the login session that the process is
 370     a part of. Please note the login session may be limited to a stub
 371     process or two.  User processes may instead be started from their
 372     systemd user manager, e.g. GUI applications started using DBus
 373     activation, as well as service processes which are shared between
 374     multiple logins of the same user. For processes that are not part
 375     of a session, returns -ENXIO.</para>
 376
 377     <para><function>sd_bus_creds_get_owner_uid()</function> will
 378     retrieve the numeric UID (user identifier) of the user who owns
 379     the user unit or login session that the process is a part of. See
 380     <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
 381     For processes that are not part of a user unit or session, returns
 382     -ENXIO.
 383     </para>
 384
 385     <para><function>sd_bus_creds_has_effective_cap()</function> will check whether the capability specified by
 386     <parameter>capability</parameter> was set in the effective capabilities mask. A positive return value means that it
 387     was set, zero means that it was not set, and a negative return value indicates an error. See <citerefentry
 388     project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> and the
 389     <varname>AmbientCapabilities=</varname> and <varname>CapabilityBoundingSet=</varname> settings in
 390     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
 391     </para>
 392
 393     <para><function>sd_bus_creds_has_permitted_cap()</function> is
 394     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 395     but will check the permitted capabilities mask.</para>
 396
 397     <para><function>sd_bus_creds_has_inheritable_cap()</function> is
 398     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 399     but will check the inheritable capabilities mask.</para>
 400
 401     <para><function>sd_bus_creds_has_bounding_cap()</function> is
 402     similar to <function>sd_bus_creds_has_effective_cap()</function>,
 403     but will check the bounding capabilities mask.</para>
 404
 405     <para><function>sd_bus_creds_get_selinux_context()</function> will
 406     retrieve the SELinux security context (label) of the process.</para>
 407
 408     <para><function>sd_bus_creds_get_audit_session_id()</function>
 409     will retrieve the audit session identifier of the process. Returns
 410     -ENXIO for processes that are not part of an audit session.</para>
 411
 412     <para><function>sd_bus_creds_get_audit_login_uid()</function> will
 413     retrieve the audit user login identifier (the identifier of the
 414     user who is "responsible" for the session). Returns -ENXIO for
 415     processes that are not part of an audit session.</para>
 416
 417     <para><function>sd_bus_creds_get_tty()</function> will retrieve
 418     the controlling TTY, without the prefixing "/dev/". Returns -ENXIO
 419     for processes that have no controlling TTY.</para>
 420
 421     <para><function>sd_bus_creds_get_unique_name()</function> will
 422     retrieve the D-Bus unique name. See <ulink
 423     url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
 424     D-Bus specification</ulink>.</para>
 425
 426     <para><function>sd_bus_creds_get_well_known_names()</function> will
 427     retrieve the set of D-Bus well-known names. See <ulink
 428     url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
 429     D-Bus specification</ulink>.</para>
 430
 431     <para><function>sd_bus_creds_get_description()</function> will
 432     retrieve a descriptive name of the bus connection of the
 433     peer. This name is useful to discern multiple bus connections by
 434     the same peer, and may be altered by the peer with the
 435     <citerefentry><refentrytitle>sd_bus_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 436     call.</para>
 437
 438     <para>All functions that take a <parameter>const
 439     char**</parameter> parameter will store the answer there as an
 440     address of a NUL-terminated string. It will be valid as long as
 441     <parameter>c</parameter> remains valid, and should not be freed or
 442     modified by the caller.</para>
 443
 444     <para>All functions that take a <parameter>char***</parameter>
 445     parameter will store the answer there as an address of an array
 446     of strings. Each individual string is NUL-terminated, and the
 447     array is NULL-terminated as a whole. It will be valid as long as
 448     <parameter>c</parameter> remains valid, and should not be freed or
 449     modified by the caller.</para>
 450   </refsect1>
 451
 452   <refsect1>
 453     <title>Return Value</title>
 454
 455     <para>On success, these calls return 0 or a positive integer. On
 456     failure, these calls return a negative errno-style error code.
 457     </para>
 458
 459     <refsect2>
 460       <title>Errors</title>
 461
 462       <para>Returned errors may indicate the following problems:</para>
 463
 464       <variablelist>
 465         <varlistentry>
 466           <term><constant>-ENODATA</constant></term>
 467
 468           <listitem><para>The given field is not available in the credentials object
 469           <parameter>c</parameter>.</para>
 470           </listitem>
 471         </varlistentry>
 472
 473         <varlistentry>
 474           <term><constant>-ENXIO</constant></term>
 475
 476           <listitem><para>The given field is not specified for the described process or peer. This will be
 477           returned by <function>sd_bus_creds_get_unit()</function>,
 478           <function>sd_bus_creds_get_slice()</function>, <function>sd_bus_creds_get_user_unit()</function>,
 479           <function>sd_bus_creds_get_user_slice()</function>, and
 480           <function>sd_bus_creds_get_session()</function> if the process is not part of a systemd system
 481           unit, systemd user unit, systemd slice, or logind session. It will be returned by
 482           <function>sd_bus_creds_get_owner_uid()</function> if the process is not part of a systemd user unit
 483           or logind session. It will also be returned by <function>sd_bus_creds_get_exe()</function> and
 484           <function>sd_bus_creds_get_cmdline()</function> for kernel threads (since these are not started
 485           from an executable binary, nor have a command line), and by
 486           <function>sd_bus_creds_get_audit_session_id()</function> and
 487           <function>sd_bus_creds_get_audit_login_uid()</function> when the process is not part of an audit
 488           session, and <function>sd_bus_creds_get_tty()</function> if the process has no controlling
 489           TTY.</para></listitem>
 490         </varlistentry>
 491
 492         <varlistentry>
 493           <term><constant>-EINVAL</constant></term>
 494
 495           <listitem><para>Specified pointer parameter is <constant>NULL</constant>.</para></listitem>
 496         </varlistentry>
 497
 498         <varlistentry>
 499           <term><constant>-ENOMEM</constant></term>
 500
 501           <listitem><para>Memory allocation failed.</para></listitem>
 502         </varlistentry>
 503       </variablelist>
 504     </refsect2>
 505   </refsect1>
 506
 507   <xi:include href="libsystemd-pkgconfig.xml" />
 508
 509   <refsect1>
 510     <title>See Also</title>
 511
 512     <para>
 513       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 514       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 515       <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 516       <citerefentry project='man-pages'><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 517       <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
 518       <citerefentry project='man-pages'><refentrytitle>credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 519       <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 520       <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 521       <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 522     </para>
 523   </refsect1>
 524
 525 </refentry>