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2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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6 SPDX-License-Identifier: LGPL-2.1+
8 Copyright © 2014 Zbigniew Jędrzejewski-Szmek
11 <refentry id="sd_bus_creds_get_pid" xmlns:xi="http://www.w3.org/2001/XInclude">
14 <title>sd_bus_creds_get_pid</title>
15 <productname>systemd</productname>
19 <refentrytitle>sd_bus_creds_get_pid</refentrytitle>
20 <manvolnum>3</manvolnum>
24 <refname>sd_bus_creds_get_pid</refname>
25 <refname>sd_bus_creds_get_ppid</refname>
26 <refname>sd_bus_creds_get_tid</refname>
27 <refname>sd_bus_creds_get_uid</refname>
28 <refname>sd_bus_creds_get_euid</refname>
29 <refname>sd_bus_creds_get_suid</refname>
30 <refname>sd_bus_creds_get_fsuid</refname>
31 <refname>sd_bus_creds_get_gid</refname>
32 <refname>sd_bus_creds_get_egid</refname>
33 <refname>sd_bus_creds_get_sgid</refname>
34 <refname>sd_bus_creds_get_fsgid</refname>
35 <refname>sd_bus_creds_get_supplementary_gids</refname>
36 <refname>sd_bus_creds_get_comm</refname>
37 <refname>sd_bus_creds_get_tid_comm</refname>
38 <refname>sd_bus_creds_get_exe</refname>
39 <refname>sd_bus_creds_get_cmdline</refname>
40 <refname>sd_bus_creds_get_cgroup</refname>
41 <refname>sd_bus_creds_get_unit</refname>
42 <refname>sd_bus_creds_get_slice</refname>
43 <refname>sd_bus_creds_get_user_unit</refname>
44 <refname>sd_bus_creds_get_user_slice</refname>
45 <refname>sd_bus_creds_get_session</refname>
46 <refname>sd_bus_creds_get_owner_uid</refname>
47 <refname>sd_bus_creds_has_effective_cap</refname>
48 <refname>sd_bus_creds_has_permitted_cap</refname>
49 <refname>sd_bus_creds_has_inheritable_cap</refname>
50 <refname>sd_bus_creds_has_bounding_cap</refname>
51 <refname>sd_bus_creds_get_selinux_context</refname>
52 <refname>sd_bus_creds_get_audit_session_id</refname>
53 <refname>sd_bus_creds_get_audit_login_uid</refname>
54 <refname>sd_bus_creds_get_tty</refname>
55 <refname>sd_bus_creds_get_unique_name</refname>
56 <refname>sd_bus_creds_get_well_known_names</refname>
57 <refname>sd_bus_creds_get_description</refname>
59 <refpurpose>Retrieve fields from a credentials object</refpurpose>
64 <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
67 <funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>
68 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
69 <paramdef>pid_t *<parameter>pid</parameter></paramdef>
73 <funcdef>int <function>sd_bus_creds_get_ppid</function></funcdef>
74 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
75 <paramdef>pid_t *<parameter>ppid</parameter></paramdef>
79 <funcdef>int <function>sd_bus_creds_get_tid</function></funcdef>
80 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
81 <paramdef>pid_t *<parameter>tid</parameter></paramdef>
85 <funcdef>int <function>sd_bus_creds_get_uid</function></funcdef>
86 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
87 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
91 <funcdef>int <function>sd_bus_creds_get_euid</function></funcdef>
92 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
93 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
97 <funcdef>int <function>sd_bus_creds_get_suid</function></funcdef>
98 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
99 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
103 <funcdef>int <function>sd_bus_creds_get_fsuid</function></funcdef>
104 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
105 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
109 <funcdef>int <function>sd_bus_creds_get_gid</function></funcdef>
110 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
111 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
115 <funcdef>int <function>sd_bus_creds_get_egid</function></funcdef>
116 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
117 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
121 <funcdef>int <function>sd_bus_creds_get_sgid</function></funcdef>
122 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
123 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
127 <funcdef>int <function>sd_bus_creds_get_fsgid</function></funcdef>
128 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
129 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
133 <funcdef>int <function>sd_bus_creds_get_supplementary_gids</function></funcdef>
134 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
135 <paramdef>const gid_t **<parameter>gids</parameter></paramdef>
139 <funcdef>int <function>sd_bus_creds_get_comm</function></funcdef>
140 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
141 <paramdef>const char **<parameter>comm</parameter></paramdef>
145 <funcdef>int <function>sd_bus_creds_get_tid_comm</function></funcdef>
146 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
147 <paramdef>const char **<parameter>comm</parameter></paramdef>
151 <funcdef>int <function>sd_bus_creds_get_exe</function></funcdef>
152 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
153 <paramdef>const char **<parameter>exe</parameter></paramdef>
157 <funcdef>int <function>sd_bus_creds_get_cmdline</function></funcdef>
158 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
159 <paramdef>char ***<parameter>cmdline</parameter></paramdef>
163 <funcdef>int <function>sd_bus_creds_get_cgroup</function></funcdef>
164 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
165 <paramdef>const char **<parameter>cgroup</parameter></paramdef>
169 <funcdef>int <function>sd_bus_creds_get_unit</function></funcdef>
170 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
171 <paramdef>const char **<parameter>unit</parameter></paramdef>
175 <funcdef>int <function>sd_bus_creds_get_slice</function></funcdef>
176 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
177 <paramdef>const char **<parameter>slice</parameter></paramdef>
181 <funcdef>int <function>sd_bus_creds_get_user_unit</function></funcdef>
182 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
183 <paramdef>const char **<parameter>unit</parameter></paramdef>
187 <funcdef>int <function>sd_bus_creds_get_user_slice</function></funcdef>
188 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
189 <paramdef>const char **<parameter>slice</parameter></paramdef>
193 <funcdef>int <function>sd_bus_creds_get_session</function></funcdef>
194 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
195 <paramdef>const char **<parameter>slice</parameter></paramdef>
199 <funcdef>int <function>sd_bus_creds_get_owner_uid</function></funcdef>
200 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
201 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
205 <funcdef>int <function>sd_bus_creds_has_effective_cap</function></funcdef>
206 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
207 <paramdef>int <parameter>capability</parameter></paramdef>
211 <funcdef>int <function>sd_bus_creds_has_permitted_cap</function></funcdef>
212 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
213 <paramdef>int <parameter>capability</parameter></paramdef>
217 <funcdef>int <function>sd_bus_creds_has_inheritable_cap</function></funcdef>
218 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
219 <paramdef>int <parameter>capability</parameter></paramdef>
223 <funcdef>int <function>sd_bus_creds_has_bounding_cap</function></funcdef>
224 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
225 <paramdef>int <parameter>capability</parameter></paramdef>
229 <funcdef>int <function>sd_bus_creds_get_selinux_context</function></funcdef>
230 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
231 <paramdef>const char **<parameter>context</parameter></paramdef>
235 <funcdef>int <function>sd_bus_creds_get_audit_session_id</function></funcdef>
236 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
237 <paramdef>uint32_t *<parameter>sessionid</parameter></paramdef>
241 <funcdef>int <function>sd_bus_creds_get_audit_login_uid</function></funcdef>
242 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
243 <paramdef>uid_t *<parameter>loginuid</parameter></paramdef>
247 <funcdef>int <function>sd_bus_creds_get_tty</function></funcdef>
248 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
249 <paramdef>const char **<parameter>tty</parameter></paramdef>
253 <funcdef>int <function>sd_bus_creds_get_unique_name</function></funcdef>
254 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
255 <paramdef>const char **<parameter>name</parameter></paramdef>
259 <funcdef>int <function>sd_bus_creds_get_well_known_names</function></funcdef>
260 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
261 <paramdef>char ***<parameter>name</parameter></paramdef>
265 <funcdef>int <function>sd_bus_creds_get_description</function></funcdef>
266 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
267 <paramdef>const char **<parameter>name</parameter></paramdef>
274 <title>Description</title>
276 <para>These functions return credential information from an
277 <parameter>sd_bus_creds</parameter> object. Credential objects may
279 <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
280 in which case they describe the credentials of the process
281 identified by the specified PID, with
282 <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
283 in which case they describe the credentials of a bus peer
284 identified by the specified bus name, with
285 <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
286 in which case they describe the credentials of the creator of a
288 <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
289 in which case they describe the credentials of the sender of the
292 <para>Not all credential fields are part of every
293 <literal>sd_bus_creds</literal> object. Use
294 <citerefentry><refentrytitle>sd_bus_creds_get_mask</refentrytitle><manvolnum>3</manvolnum></citerefentry>
295 to determine the mask of fields available.</para>
297 <para><function>sd_bus_creds_get_pid()</function> will retrieve
298 the PID (process identifier). Similarly,
299 <function>sd_bus_creds_get_ppid()</function> will retrieve the
300 parent PID. Note that PID 1 has no parent process, in which case
301 -ENXIO is returned.</para>
303 <para><function>sd_bus_creds_get_tid()</function> will retrieve the
304 TID (thread identifier).</para>
306 <para><function>sd_bus_creds_get_uid()</function> will retrieve
307 the numeric UID (user identifier). Similarly,
308 <function>sd_bus_creds_get_euid()</function> returns the effective
309 UID, <function>sd_bus_creds_get_suid()</function> the saved UID
310 and <function>sd_bus_creds_get_fsuid()</function> the file system
313 <para><function>sd_bus_creds_get_gid()</function> will retrieve the
314 numeric GID (group identifier). Similarly,
315 <function>sd_bus_creds_get_egid()</function> returns the effective
316 GID, <function>sd_bus_creds_get_sgid()</function> the saved GID
317 and <function>sd_bus_creds_get_fsgid()</function> the file system
320 <para><function>sd_bus_creds_get_supplementary_gids()</function>
321 will retrieve the supplementary GIDs list.</para>
323 <para><function>sd_bus_creds_get_comm()</function> will retrieve the
324 comm field (truncated name of the executable, as stored in
325 <filename>/proc/<replaceable>pid</replaceable>/comm</filename>).
328 <para><function>sd_bus_creds_get_tid_comm()</function> will retrieve
329 the comm field of the thread (as stored in
330 <filename>/proc/<replaceable>pid</replaceable>/task/<replaceable>tid</replaceable>/comm</filename>).
333 <para><function>sd_bus_creds_get_exe()</function> will retrieve
334 the path to the program executable (as stored in the
335 <filename>/proc/<replaceable>pid</replaceable>/exe</filename>
336 link, but with the <literal> (deleted)</literal> suffix removed). Note
337 that kernel threads do not have an executable path, in which case
338 -ENXIO is returned.</para>
340 <para><function>sd_bus_creds_get_cmdline()</function> will
341 retrieve an array of command line arguments (as stored in
342 <filename>/proc/<replaceable>pid</replaceable>/cmdline</filename>). Note
343 that kernel threads do not have a command line, in which case
344 -ENXIO is returned.</para>
346 <para><function>sd_bus_creds_get_cgroup()</function> will retrieve
347 the control group path. See <ulink
348 url="https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt">cgroups.txt</ulink>.
351 <para><function>sd_bus_creds_get_unit()</function> will retrieve
352 the systemd unit name (in the system instance of systemd) that the
353 process is a part of. See
354 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
355 processes that are not part of a unit, returns -ENXIO.
358 <para><function>sd_bus_creds_get_user_unit()</function> will
359 retrieve the systemd unit name (in the user instance of systemd)
360 that the process is a part of. See
361 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
362 processes that are not part of a user unit, returns -ENXIO.
365 <para><function>sd_bus_creds_get_slice()</function> will retrieve
366 the systemd slice (a unit in the system instance of systemd) that
367 the process is a part of. See
368 <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Similarly,
369 <function>sd_bus_creds_get_user_slice()</function> retrieves the
370 systemd slice of the process, in the user instance of systemd.
373 <para><function>sd_bus_creds_get_session()</function> will
374 retrieve the identifier of the login session that the process is
375 a part of. Please note the login session may be limited to a stub
376 process or two. User processes may instead be started from their
377 elogind user manager, e.g. GUI applications started using DBus
378 activation, as well as service processes which are shared between
379 multiple logins of the same user. For processes that are not part
380 of a session, returns -ENXIO.</para>
382 <para><function>sd_bus_creds_get_owner_uid()</function> will
383 retrieve the numeric UID (user identifier) of the user who owns
384 the user unit or login session that the process is a part of. See
385 <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
386 For processes that are not part of a user unit or session, returns
390 <para><function>sd_bus_creds_has_effective_cap()</function> will check whether the capability specified by
391 <parameter>capability</parameter> was set in the effective capabilities mask. A positive return value means that it
392 was set, zero means that it was not set, and a negative return value indicates an error. See <citerefentry
393 project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> and the
394 <varname>AmbientCapabilities=</varname> and <varname>CapabilityBoundingSet=</varname> settings in
395 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
398 <para><function>sd_bus_creds_has_permitted_cap()</function> is
399 similar to <function>sd_bus_creds_has_effective_cap()</function>,
400 but will check the permitted capabilities mask.</para>
402 <para><function>sd_bus_creds_has_inheritable_cap()</function> is
403 similar to <function>sd_bus_creds_has_effective_cap()</function>,
404 but will check the inheritable capabilities mask.</para>
406 <para><function>sd_bus_creds_has_bounding_cap()</function> is
407 similar to <function>sd_bus_creds_has_effective_cap()</function>,
408 but will check the bounding capabilities mask.</para>
410 <para><function>sd_bus_creds_get_selinux_context()</function> will
411 retrieve the SELinux security context (label) of the process.</para>
413 <para><function>sd_bus_creds_get_audit_session_id()</function>
414 will retrieve the audit session identifier of the process. Returns
415 -ENXIO for processes that are not part of an audit session.</para>
417 <para><function>sd_bus_creds_get_audit_login_uid()</function> will
418 retrieve the audit user login identifier (the identifier of the
419 user who is "responsible" for the session). Returns -ENXIO for
420 processes that are not part of an audit session.</para>
422 <para><function>sd_bus_creds_get_tty()</function> will retrieve
423 the controlling TTY, without the prefixing "/dev/". Returns -ENXIO
424 for processes that have no controlling TTY.</para>
426 <para><function>sd_bus_creds_get_unique_name()</function> will
427 retrieve the D-Bus unique name. See <ulink
428 url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
429 D-Bus specification</ulink>.</para>
431 <para><function>sd_bus_creds_get_well_known_names()</function> will
432 retrieve the set of D-Bus well-known names. See <ulink
433 url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
434 D-Bus specification</ulink>.</para>
436 <para><function>sd_bus_creds_get_description()</function> will
437 retrieve a descriptive name of the bus connection of the
438 peer. This name is useful to discern multiple bus connections by
439 the same peer, and may be altered by the peer with the
440 <citerefentry><refentrytitle>sd_bus_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
443 <para>All functions that take a <parameter>const
444 char**</parameter> parameter will store the answer there as an
445 address of a NUL-terminated string. It will be valid as long as
446 <parameter>c</parameter> remains valid, and should not be freed or
447 modified by the caller.</para>
449 <para>All functions that take a <parameter>char***</parameter>
450 parameter will store the answer there as an address of an array
451 of strings. Each individual string is NUL-terminated, and the
452 array is NULL-terminated as a whole. 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>
458 <title>Return Value</title>
460 <para>On success, these calls return 0 or a positive integer. On
461 failure, these calls return a negative errno-style error code.
466 <title>Errors</title>
468 <para>Returned errors may indicate the following problems:</para>
472 <term><constant>-ENODATA</constant></term>
474 <listitem><para>The given field is not available in the
475 credentials object <parameter>c</parameter>.</para>
480 <term><constant>-ENXIO</constant></term>
482 <listitem><para>The given field is not specified for the described
483 process or peer. This will be returned by
484 <function>sd_bus_creds_get_unit()</function>,
485 <function>sd_bus_creds_get_slice()</function>,
486 <function>sd_bus_creds_get_user_unit()</function>,
487 <function>sd_bus_creds_get_user_slice()</function>, and
488 <function>sd_bus_creds_get_session()</function> if the process is
489 not part of a systemd system unit, systemd user unit, systemd
490 slice, or logind session. It will be returned by
491 <function>sd_bus_creds_get_owner_uid()</function> if the process is
492 not part of a elogind user unit or logind session. It will also be
493 returned by <function>sd_bus_creds_get_exe()</function> and
494 <function>sd_bus_creds_get_cmdline()</function> for kernel
495 threads (since these are not started from an executable binary,
496 nor have a command line), and by
497 <function>sd_bus_creds_get_audit_session_id()</function> and
498 <function>sd_bus_creds_get_audit_login_uid()</function> when
499 the process is not part of an audit session, and
500 <function>sd_bus_creds_get_tty()</function> if the process has
507 <term><constant>-EINVAL</constant></term>
509 <listitem><para>Specified pointer parameter is <constant>NULL</constant>.
514 <term><constant>-ENOMEM</constant></term>
516 <listitem><para>Memory allocation failed.</para></listitem>
521 <xi:include href="libelogind-pkgconfig.xml" />
524 <title>See Also</title>
527 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
528 <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
529 <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
530 <citerefentry project='man-pages'><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
531 <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
532 <citerefentry project='man-pages'><refentrytitle>credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
533 <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
534 <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
535 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>