1 <?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
6 This file is part of systemd.
8 Copyright 2014 Zbigniew Jędrzejewski-Szmek
10 systemd is free software; you can redistribute it and/or modify it
11 under the terms of the GNU Lesser General Public License as published by
12 the Free Software Foundation; either version 2.1 of the License, or
13 (at your option) any later version.
15 systemd is distributed in the hope that it will be useful, but
16 WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 Lesser General Public License for more details.
20 You should have received a copy of the GNU Lesser General Public License
21 along with systemd; If not, see <http://www.gnu.org/licenses/>.
24 <refentry id="sd_bus_creds_get_pid">
27 <title>sd_bus_creds_get_pid</title>
28 <productname>systemd</productname>
32 <contrib>A monkey with a typewriter</contrib>
33 <firstname>Zbigniew</firstname>
34 <surname>Jędrzejewski-Szmek</surname>
35 <email>zbyszek@in.waw.pl</email>
41 <refentrytitle>sd_bus_creds_get_pid</refentrytitle>
42 <manvolnum>3</manvolnum>
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_slice</refname>
65 <refname>sd_bus_creds_get_user_unit</refname>
66 <refname>sd_bus_creds_get_user_slice</refname>
67 <refname>sd_bus_creds_get_session</refname>
68 <refname>sd_bus_creds_get_owner_uid</refname>
69 <refname>sd_bus_creds_has_effective_cap</refname>
70 <refname>sd_bus_creds_has_permitted_cap</refname>
71 <refname>sd_bus_creds_has_inheritable_cap</refname>
72 <refname>sd_bus_creds_has_bounding_cap</refname>
73 <refname>sd_bus_creds_get_selinux_context</refname>
74 <refname>sd_bus_creds_get_audit_session_id</refname>
75 <refname>sd_bus_creds_get_audit_login_uid</refname>
76 <refname>sd_bus_creds_get_tty</refname>
77 <refname>sd_bus_creds_get_unique_name</refname>
78 <refname>sd_bus_creds_get_well_known_names</refname>
79 <refname>sd_bus_creds_get_description</refname>
81 <refpurpose>Retrieve fields from a credentials object</refpurpose>
86 <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo>
89 <funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>
90 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
91 <paramdef>pid_t *<parameter>pid</parameter></paramdef>
95 <funcdef>int <function>sd_bus_creds_get_ppid</function></funcdef>
96 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
97 <paramdef>pid_t *<parameter>ppid</parameter></paramdef>
101 <funcdef>int <function>sd_bus_creds_get_tid</function></funcdef>
102 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
103 <paramdef>pid_t *<parameter>tid</parameter></paramdef>
107 <funcdef>int <function>sd_bus_creds_get_uid</function></funcdef>
108 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
109 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
113 <funcdef>int <function>sd_bus_creds_get_euid</function></funcdef>
114 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
115 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
119 <funcdef>int <function>sd_bus_creds_get_suid</function></funcdef>
120 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
121 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
125 <funcdef>int <function>sd_bus_creds_get_fsuid</function></funcdef>
126 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
127 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
131 <funcdef>int <function>sd_bus_creds_get_gid</function></funcdef>
132 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
133 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
137 <funcdef>int <function>sd_bus_creds_get_egid</function></funcdef>
138 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
139 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
143 <funcdef>int <function>sd_bus_creds_get_sgid</function></funcdef>
144 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
145 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
149 <funcdef>int <function>sd_bus_creds_get_fsgid</function></funcdef>
150 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
151 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
155 <funcdef>int <function>sd_bus_creds_get_supplementary_gids</function></funcdef>
156 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
157 <paramdef>const gid_t **<parameter>gids</parameter></paramdef>
161 <funcdef>int <function>sd_bus_creds_get_comm</function></funcdef>
162 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
163 <paramdef>const char **<parameter>comm</parameter></paramdef>
167 <funcdef>int <function>sd_bus_creds_get_tid_comm</function></funcdef>
168 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
169 <paramdef>const char **<parameter>comm</parameter></paramdef>
173 <funcdef>int <function>sd_bus_creds_get_exe</function></funcdef>
174 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
175 <paramdef>const char **<parameter>exe</parameter></paramdef>
179 <funcdef>int <function>sd_bus_creds_get_cmdline</function></funcdef>
180 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
181 <paramdef>char ***<parameter>cmdline</parameter></paramdef>
185 <funcdef>int <function>sd_bus_creds_get_cgroup</function></funcdef>
186 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
187 <paramdef>const char **<parameter>cgroup</parameter></paramdef>
191 <funcdef>int <function>sd_bus_creds_get_unit</function></funcdef>
192 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
193 <paramdef>const char **<parameter>unit</parameter></paramdef>
197 <funcdef>int <function>sd_bus_creds_get_slice</function></funcdef>
198 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
199 <paramdef>const char **<parameter>slice</parameter></paramdef>
203 <funcdef>int <function>sd_bus_creds_get_user_unit</function></funcdef>
204 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
205 <paramdef>const char **<parameter>unit</parameter></paramdef>
209 <funcdef>int <function>sd_bus_creds_get_user_slice</function></funcdef>
210 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
211 <paramdef>const char **<parameter>slice</parameter></paramdef>
215 <funcdef>int <function>sd_bus_creds_get_session</function></funcdef>
216 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
217 <paramdef>const char **<parameter>slice</parameter></paramdef>
221 <funcdef>int <function>sd_bus_creds_get_owner_uid</function></funcdef>
222 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
223 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
227 <funcdef>int <function>sd_bus_creds_has_effective_cap</function></funcdef>
228 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
229 <paramdef>int <parameter>capability</parameter></paramdef>
233 <funcdef>int <function>sd_bus_creds_has_permitted_cap</function></funcdef>
234 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
235 <paramdef>int <parameter>capability</parameter></paramdef>
239 <funcdef>int <function>sd_bus_creds_has_inheritable_cap</function></funcdef>
240 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
241 <paramdef>int <parameter>capability</parameter></paramdef>
245 <funcdef>int <function>sd_bus_creds_has_bounding_cap</function></funcdef>
246 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
247 <paramdef>int <parameter>capability</parameter></paramdef>
251 <funcdef>int <function>sd_bus_creds_get_selinux_context</function></funcdef>
252 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
253 <paramdef>const char **<parameter>context</parameter></paramdef>
257 <funcdef>int <function>sd_bus_creds_get_audit_session_id</function></funcdef>
258 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
259 <paramdef>uint32_t *<parameter>sessionid</parameter></paramdef>
263 <funcdef>int <function>sd_bus_creds_get_audit_login_uid</function></funcdef>
264 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
265 <paramdef>uid_t *<parameter>loginuid</parameter></paramdef>
269 <funcdef>int <function>sd_bus_creds_get_tty</function></funcdef>
270 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
271 <paramdef>const char **<parameter>tty</parameter></paramdef>
275 <funcdef>int <function>sd_bus_creds_get_unique_name</function></funcdef>
276 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
277 <paramdef>const char **<parameter>name</parameter></paramdef>
281 <funcdef>int <function>sd_bus_creds_get_well_known_names</function></funcdef>
282 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
283 <paramdef>char ***<parameter>name</parameter></paramdef>
287 <funcdef>int <function>sd_bus_creds_get_description</function></funcdef>
288 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
289 <paramdef>const char **<parameter>name</parameter></paramdef>
296 <title>Description</title>
298 <para>These functions return credential information from an
299 <parameter>sd_bus_creds</parameter> object. Credential objects may
301 <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
302 in which case they describe the credentials of the process
303 identified by the specified PID, with
304 <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
305 in which case they describe the credentials of a bus peer
306 identified by the specified bus name, with
307 <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
308 in which case they describe the credentials of the creator of a
310 <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
311 in which case they describe the credentials of the sender of the
314 <para>Not all credential fields are part of every
315 <literal>sd_bus_creds</literal> object. Use
316 <citerefentry><refentrytitle>sd_bus_creds_get_mask</refentrytitle><manvolnum>3</manvolnum></citerefentry>
317 to determine the mask of fields available.</para>
319 <para><function>sd_bus_creds_get_pid()</function> will retrieve
320 the PID (process identifier). Similarly,
321 <function>sd_bus_creds_get_ppid()</function> will retrieve the
322 parent PID. Note that PID 1 has no parent process, in which case
323 -ENXIO is returned.</para>
325 <para><function>sd_bus_creds_get_tid()</function> will retrieve the
326 TID (thread identifier).</para>
328 <para><function>sd_bus_creds_get_uid()</function> will retrieve
329 the numeric UID (user identifier). Similarly,
330 <function>sd_bus_creds_get_euid()</function> returns the effective
331 UID, <function>sd_bus_creds_get_suid()</function> the saved UID
332 and <function>sd_bus_creds_get_fsuid()</function> the file system
335 <para><function>sd_bus_creds_get_gid()</function> will retrieve the
336 numeric GID (group identifier). Similarly,
337 <function>sd_bus_creds_get_egid()</function> returns the effective
338 GID, <function>sd_bus_creds_get_sgid()</function> the saved GID
339 and <function>sd_bus_creds_get_fsgid()</function> the file system
342 <para><function>sd_bus_creds_get_supplementary_gids()</function>
343 will retrieve the supplementary GIDs list.</para>
345 <para><function>sd_bus_creds_get_comm()</function> will retrieve the
346 comm field (truncated name of the executable, as stored in
347 <filename>/proc/<replaceable>pid</replaceable>/comm</filename>).
350 <para><function>sd_bus_creds_get_tid_comm()</function> will retrieve
351 the comm field of the thread (as stored in
352 <filename>/proc/<replaceable>pid</replaceable>/task/<replaceable>tid</replaceable>/comm</filename>).
355 <para><function>sd_bus_creds_get_exe()</function> will retrieve
356 the path to the program executable (as stored in the
357 <filename>/proc/<replaceable>pid</replaceable>/exe</filename>
358 link, but with the <literal> (deleted)</literal> suffix removed). Note
359 that kernel threads do not have an executable path, in which case
360 -ENXIO is returned.</para>
362 <para><function>sd_bus_creds_get_cmdline()</function> will
363 retrieve an array of command line arguments (as stored in
364 <filename>/proc/<replaceable>pid</replaceable>/cmdline</filename>). Note
365 that kernel threads do not have a command line, in which case
366 -ENXIO is returned.</para>
368 <para><function>sd_bus_creds_get_cgroup()</function> will retrieve
369 the control group path. See <ulink
370 url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.
373 <para><function>sd_bus_creds_get_unit()</function> will retrieve
374 the systemd unit name (in the system instance of systemd) that the
375 process is a part of. See
376 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
377 processes that are not part of a unit, returns -ENXIO.
380 <para><function>sd_bus_creds_get_user_unit()</function> will
381 retrieve the systemd unit name (in the user instance of systemd)
382 that the process is a part of. See
383 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>. For
384 processes that are not part of a user unit, returns -ENXIO.
387 <para><function>sd_bus_creds_get_slice()</function> will retrieve
388 the systemd slice (a unit in the system instance of systemd) that
389 the process is a part of. See
390 <citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>. Similarly,
391 <function>sd_bus_creds_get_user_slice()</function> retrieves the
392 systemd slice of the process, in the user instance of systemd.
395 <para><function>sd_bus_creds_get_session()</function> will
396 retrieve the identifier of the login session that the process is
398 <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. For
399 processes that are not part of a session, returns -ENXIO.
402 <para><function>sd_bus_creds_get_owner_uid()</function> will
403 retrieve the numeric UID (user identifier) of the user who owns
404 the login session that the process is a part of. See
405 <citerefentry><refentrytitle>systemd-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
406 For processes that are not part of a session, returns -ENXIO.
409 <para><function>sd_bus_creds_has_effective_cap()</function> will check whether the capability specified by
410 <parameter>capability</parameter> was set in the effective capabilities mask. A positive return value means that it
411 was set, zero means that it was not set, and a negative return value indicates an error. See <citerefentry
412 project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry> and the
413 <varname>AmbientCapabilities=</varname> and <varname>CapabilityBoundingSet=</varname> settings in
414 <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
417 <para><function>sd_bus_creds_has_permitted_cap()</function> is
418 similar to <function>sd_bus_creds_has_effective_cap()</function>,
419 but will check the permitted capabilities mask.</para>
421 <para><function>sd_bus_creds_has_inheritable_cap()</function> is
422 similar to <function>sd_bus_creds_has_effective_cap()</function>,
423 but will check the inheritable capabilities mask.</para>
425 <para><function>sd_bus_creds_has_bounding_cap()</function> is
426 similar to <function>sd_bus_creds_has_effective_cap()</function>,
427 but will check the bounding capabilities mask.</para>
429 <para><function>sd_bus_creds_get_selinux_context()</function> will
430 retrieve the SELinux security context (label) of the process.</para>
432 <para><function>sd_bus_creds_get_audit_session_id()</function>
433 will retrieve the audit session identifier of the process. Returns
434 -ENXIO for processes that are not part of an audit session.</para>
436 <para><function>sd_bus_creds_get_audit_login_uid()</function> will
437 retrieve the audit user login identifier (the identifier of the
438 user who is "responsible" for the session). Returns -ENXIO for
439 processes that are not part of an audit session.</para>
441 <para><function>sd_bus_creds_get_tty()</function> will retrieve
442 the controlling TTY, without the prefixing "/dev/". Returns -ENXIO
443 for processes that have no controlling TTY.</para>
445 <para><function>sd_bus_creds_get_unique_name()</function> will
446 retrieve the D-Bus unique name. See <ulink
447 url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
448 D-Bus specification</ulink>.</para>
450 <para><function>sd_bus_creds_get_well_known_names()</function> will
451 retrieve the set of D-Bus well-known names. See <ulink
452 url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
453 D-Bus specification</ulink>.</para>
455 <para><function>sd_bus_creds_get_description()</function> will
456 retrieve a descriptive name of the bus connection of the
457 peer. This name is useful to discern multiple bus connections by
458 the same peer, and may be altered by the peer with the
459 <citerefentry><refentrytitle>sd_bus_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
462 <para>All functions that take a <parameter>const
463 char**</parameter> parameter will store the answer there as an
464 address of a NUL-terminated string. It will be valid as long as
465 <parameter>c</parameter> remains valid, and should not be freed or
466 modified by the caller.</para>
468 <para>All functions that take a <parameter>char***</parameter>
469 parameter will store the answer there as an address of an array
470 of strings. Each individual string is NUL-terminated, and the
471 array is NULL-terminated as a whole. It will be valid as long as
472 <parameter>c</parameter> remains valid, and should not be freed or
473 modified by the caller.</para>
477 <title>Return Value</title>
479 <para>On success, these calls return 0 or a positive integer. On
480 failure, these calls return a negative errno-style error code.
485 <title>Errors</title>
487 <para>Returned errors may indicate the following problems:</para>
491 <term><constant>-ENODATA</constant></term>
493 <listitem><para>The given field is not available in the
494 credentials object <parameter>c</parameter>.</para>
499 <term><constant>-ENXIO</constant></term>
501 <listitem><para>The given field is not specified for the described
502 process or peer. This will be returned by
503 <function>sd_bus_get_unit()</function>,
504 <function>sd_bus_get_slice()</function>,
505 <function>sd_bus_get_user_unit()</function>,
506 <function>sd_bus_get_user_slice()</function>,
507 <function>sd_bus_get_session()</function>, and
508 <function>sd_bus_get_owner_uid()</function> if the process is
509 not part of a systemd system unit, systemd user unit, systemd
510 slice, or logind session. It will also be returned by
511 <function>sd_bus_creds_get_exe()</function> and
512 <function>sd_bus_creds_get_cmdline()</function> for kernel
513 threads (since these are not started from an executable binary,
514 nor have a command line), and by
515 <function>sd_bus_creds_get_audit_session_id()</function> and
516 <function>sd_bus_creds_get_audit_login_uid()</function> when
517 the process is not part of an audit session, and
518 <function>sd_bus_creds_get_tty()</function> if the process has
525 <term><constant>-EINVAL</constant></term>
527 <listitem><para>Specified pointer parameter is <constant>NULL</constant>.
532 <term><constant>-ENOMEM</constant></term>
534 <listitem><para>Memory allocation failed.</para></listitem>
542 <para><function>sd_bus_creds_get_pid()</function> and the other
543 functions described here are available as a shared library, which
544 can be compiled and linked to with the
545 <constant>libelogind</constant> <citerefentry
546 project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
551 <title>See Also</title>
554 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
555 <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
556 <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
557 <citerefentry project='man-pages'><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
558 <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
559 <citerefentry project='man-pages'><refentrytitle>credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
560 <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
561 <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
562 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>