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 elogind.
8 Copyright 2014 Zbigniew Jędrzejewski-Szmek
10 elogind 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 elogind 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 elogind; 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>elogind</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_session</refname>
64 <refname>sd_bus_creds_get_owner_uid</refname>
65 <refname>sd_bus_creds_has_effective_cap</refname>
66 <refname>sd_bus_creds_has_permitted_cap</refname>
67 <refname>sd_bus_creds_has_inheritable_cap</refname>
68 <refname>sd_bus_creds_has_bounding_cap</refname>
69 <refname>sd_bus_creds_get_selinux_context</refname>
70 <refname>sd_bus_creds_get_audit_session_id</refname>
71 <refname>sd_bus_creds_get_audit_login_uid</refname>
72 <refname>sd_bus_creds_get_tty</refname>
73 <refname>sd_bus_creds_get_unique_name</refname>
74 <refname>sd_bus_creds_get_well_known_names</refname>
75 <refname>sd_bus_creds_get_description</refname>
77 <refpurpose>Retrieve fields from a credentials object</refpurpose>
82 <funcsynopsisinfo>#include <elogind/sd-bus.h></funcsynopsisinfo>
85 <funcdef>int <function>sd_bus_creds_get_pid</function></funcdef>
86 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
87 <paramdef>pid_t *<parameter>pid</parameter></paramdef>
91 <funcdef>int <function>sd_bus_creds_get_ppid</function></funcdef>
92 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
93 <paramdef>pid_t *<parameter>ppid</parameter></paramdef>
97 <funcdef>int <function>sd_bus_creds_get_tid</function></funcdef>
98 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
99 <paramdef>pid_t *<parameter>tid</parameter></paramdef>
103 <funcdef>int <function>sd_bus_creds_get_uid</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_euid</function></funcdef>
110 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
111 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
115 <funcdef>int <function>sd_bus_creds_get_suid</function></funcdef>
116 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
117 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
121 <funcdef>int <function>sd_bus_creds_get_fsuid</function></funcdef>
122 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
123 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
127 <funcdef>int <function>sd_bus_creds_get_gid</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_egid</function></funcdef>
134 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
135 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
139 <funcdef>int <function>sd_bus_creds_get_sgid</function></funcdef>
140 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
141 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
145 <funcdef>int <function>sd_bus_creds_get_fsgid</function></funcdef>
146 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
147 <paramdef>gid_t *<parameter>gid</parameter></paramdef>
151 <funcdef>int <function>sd_bus_creds_get_supplementary_gids</function></funcdef>
152 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
153 <paramdef>const gid_t **<parameter>gids</parameter></paramdef>
157 <funcdef>int <function>sd_bus_creds_get_comm</function></funcdef>
158 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
159 <paramdef>const char **<parameter>comm</parameter></paramdef>
163 <funcdef>int <function>sd_bus_creds_get_tid_comm</function></funcdef>
164 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
165 <paramdef>const char **<parameter>comm</parameter></paramdef>
169 <funcdef>int <function>sd_bus_creds_get_exe</function></funcdef>
170 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
171 <paramdef>const char **<parameter>exe</parameter></paramdef>
175 <funcdef>int <function>sd_bus_creds_get_cmdline</function></funcdef>
176 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
177 <paramdef>char ***<parameter>cmdline</parameter></paramdef>
181 <funcdef>int <function>sd_bus_creds_get_cgroup</function></funcdef>
182 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
183 <paramdef>const char **<parameter>cgroup</parameter></paramdef>
187 <funcdef>int <function>sd_bus_creds_get_session</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_owner_uid</function></funcdef>
194 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
195 <paramdef>uid_t *<parameter>uid</parameter></paramdef>
199 <funcdef>int <function>sd_bus_creds_has_effective_cap</function></funcdef>
200 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
201 <paramdef>int <parameter>capability</parameter></paramdef>
205 <funcdef>int <function>sd_bus_creds_has_permitted_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_inheritable_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_bounding_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_get_selinux_context</function></funcdef>
224 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
225 <paramdef>const char **<parameter>context</parameter></paramdef>
229 <funcdef>int <function>sd_bus_creds_get_audit_session_id</function></funcdef>
230 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
231 <paramdef>uint32_t *<parameter>sessionid</parameter></paramdef>
235 <funcdef>int <function>sd_bus_creds_get_audit_login_uid</function></funcdef>
236 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
237 <paramdef>uid_t *<parameter>loginuid</parameter></paramdef>
241 <funcdef>int <function>sd_bus_creds_get_tty</function></funcdef>
242 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
243 <paramdef>const char **<parameter>tty</parameter></paramdef>
247 <funcdef>int <function>sd_bus_creds_get_unique_name</function></funcdef>
248 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
249 <paramdef>const char **<parameter>name</parameter></paramdef>
253 <funcdef>int <function>sd_bus_creds_get_well_known_names</function></funcdef>
254 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
255 <paramdef>char ***<parameter>name</parameter></paramdef>
259 <funcdef>int <function>sd_bus_creds_get_description</function></funcdef>
260 <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
261 <paramdef>const char **<parameter>name</parameter></paramdef>
268 <title>Description</title>
270 <para>These functions return credential information from an
271 <parameter>sd_bus_creds</parameter> object. Credential objects may
273 <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
274 in which case they describe the credentials of the process
275 identified by the specified PID, with
276 <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
277 in which case they describe the credentials of a bus peer
278 identified by the specified bus name, with
279 <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
280 in which case they describe the credentials of the creator of a
282 <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
283 in which case they describe the credentials of the sender of the
286 <para>Not all credential fields are part of every
287 <literal>sd_bus_creds</literal> object. Use
288 <citerefentry><refentrytitle>sd_bus_creds_get_mask</refentrytitle><manvolnum>3</manvolnum></citerefentry>
289 to determine the mask of fields available.</para>
291 <para><function>sd_bus_creds_get_pid()</function> will retrieve
292 the PID (process identifier). Similarly,
293 <function>sd_bus_creds_get_ppid()</function> will retrieve the
294 parent PID. Note that PID 1 has no parent process, in which case
295 -ENXIO is returned.</para>
297 <para><function>sd_bus_creds_get_tid()</function> will retrieve the
298 TID (thread identifier).</para>
300 <para><function>sd_bus_creds_get_uid()</function> will retrieve
301 the numeric UID (user identifier). Similarly,
302 <function>sd_bus_creds_get_euid()</function> returns the effective
303 UID, <function>sd_bus_creds_get_suid()</function> the saved UID
304 and <function>sd_bus_creds_get_fsuid()</function> the file system
307 <para><function>sd_bus_creds_get_gid()</function> will retrieve the
308 numeric GID (group identifier). Similarly,
309 <function>sd_bus_creds_get_egid()</function> returns the effective
310 GID, <function>sd_bus_creds_get_sgid()</function> the saved GID
311 and <function>sd_bus_creds_get_fsgid()</function> the file system
314 <para><function>sd_bus_creds_get_supplementary_gids()</function>
315 will retrieve the supplementary GIDs list.</para>
317 <para><function>sd_bus_creds_get_comm()</function> will retrieve the
318 comm field (truncated name of the executable, as stored in
319 <filename>/proc/<replaceable>pid</replaceable>/comm</filename>).
322 <para><function>sd_bus_creds_get_tid_comm()</function> will retrieve
323 the comm field of the thread (as stored in
324 <filename>/proc/<replaceable>pid</replaceable>/task/<replaceable>tid</replaceable>/comm</filename>).
327 <para><function>sd_bus_creds_get_exe()</function> will retrieve
328 the path to the program executable (as stored in the
329 <filename>/proc/<replaceable>pid</replaceable>/exe</filename>
330 link, but with the <literal> (deleted)</literal> suffix removed). Note
331 that kernel threads do not have an executable path, in which case
332 -ENXIO is returned.</para>
334 <para><function>sd_bus_creds_get_cmdline()</function> will
335 retrieve an array of command line arguments (as stored in
336 <filename>/proc/<replaceable>pid</replaceable>/cmdline</filename>). Note
337 that kernel threads do not have a command line, in which case
338 -ENXIO is returned.</para>
340 <para><function>sd_bus_creds_get_cgroup()</function> will retrieve
341 the cgroup path. See <ulink
342 url="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt">cgroups.txt</ulink>.
345 <para><function>sd_bus_creds_get_session()</function> will
346 retrieve the identifier of the login session that the process is
348 <citerefentry><refentrytitle>elogind-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>. For
349 processes that are not part of a session, returns -ENXIO.
352 <para><function>sd_bus_creds_get_owner_uid()</function> will
353 retrieve the numeric UID (user identifier) of the user who owns
354 the login session that the process is a part of. See
355 <citerefentry><refentrytitle>elogind-logind.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
356 For processes that are not part of a session, returns -ENXIO.
359 <para><function>sd_bus_creds_has_effective_cap()</function> will
360 check whether the capability specified by
361 <parameter>capability</parameter> was set in the effective
362 capabilities mask. A positive return value means that is was
363 set, zero means that it was not set, and a negative return
364 value indicates an error. See
365 <citerefentry project='man-pages'><refentrytitle>capabilities</refentrytitle><manvolnum>7</manvolnum></citerefentry>
366 and <varname>Capabilities=</varname> and
367 <varname>CapabilityBoundingSet=</varname> settings in
368 <citerefentry><refentrytitle>elogind.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
371 <para><function>sd_bus_creds_has_permitted_cap()</function> is
372 similar to <function>sd_bus_creds_has_effective_cap()</function>,
373 but will check the permitted capabilities mask.</para>
375 <para><function>sd_bus_creds_has_inheritable_cap()</function> is
376 similar to <function>sd_bus_creds_has_effective_cap()</function>,
377 but will check the inheritable capabilities mask.</para>
379 <para><function>sd_bus_creds_has_bounding_cap()</function> is
380 similar to <function>sd_bus_creds_has_effective_cap()</function>,
381 but will check the bounding capabilities mask.</para>
383 <para><function>sd_bus_creds_get_selinux_context()</function> will
384 retrieve the SELinux security context (label) of the process.</para>
386 <para><function>sd_bus_creds_get_audit_session_id()</function>
387 will retrieve the audit session identifier of the process. Returns
388 -ENXIO for processes that are not part of an audit session.</para>
390 <para><function>sd_bus_creds_get_audit_login_uid()</function> will
391 retrieve the audit user login identifier (the identifier of the
392 user who is "responsible" for the session). Returns -ENXIO for
393 processes that are not part of an audit session.</para>
395 <para><function>sd_bus_creds_get_tty()</function> will retrieve
396 the controlling TTY, without the prefixing "/dev/". Returns -ENXIO
397 for processes that have no controlling TTY.</para>
399 <para><function>sd_bus_creds_get_unique_name()</function> will
400 retrieve the D-Bus unique name. See <ulink
401 url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
402 D-Bus specification</ulink>.</para>
404 <para><function>sd_bus_creds_get_well_known_names()</function> will
405 retrieve the set of D-Bus well-known names. See <ulink
406 url="http://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-names-bus">The
407 D-Bus specification</ulink>.</para>
409 <para><function>sd_bus_creds_get_description()</function> will
410 retrieve a descriptive name of the bus connection of the
411 peer. This name is useful to discern multiple bus connections by
412 the same peer, and may be altered by the peer with the
413 <citerefentry><refentrytitle>sd_bus_set_description</refentrytitle><manvolnum>3</manvolnum></citerefentry>
416 <para>All functions that take a <parameter>const
417 char**</parameter> parameter will store the answer there as an
418 address of a NUL-terminated string. It will be valid as long as
419 <parameter>c</parameter> remains valid, and should not be freed or
420 modified by the caller.</para>
422 <para>All functions that take a <parameter>char***</parameter>
423 parameter will store the answer there as an address of an array
424 of strings. Each individual string is NUL-terminated, and the
425 array is NULL-terminated as a whole. It will be valid as long as
426 <parameter>c</parameter> remains valid, and should not be freed or
427 modified by the caller.</para>
431 <title>Return Value</title>
433 <para>On success, these calls return 0 or a positive integer. On
434 failure, these calls return a negative errno-style error code.
439 <title>Errors</title>
441 <para>Returned errors may indicate the following problems:</para>
445 <term><constant>-ENODATA</constant></term>
447 <listitem><para>The given field is not available in the
448 credentials object <parameter>c</parameter>.</para>
453 <term><constant>-ENXIO</constant></term>
455 <listitem><para>The given field is not specified for the described
456 process or peer. This will be returned by
457 <function>sd_bus_get_session()</function>, and
458 <function>sd_bus_get_owner_uid()</function> if the process is
459 not part of a elogind system unit, systemd user unit, systemd
460 slice, or logind session. It will also be returned by
461 <function>sd_bus_creds_get_exe()</function> and
462 <function>sd_bus_creds_get_cmdline()</function> for kernel
463 threads (since these are not started from an executable binary,
464 nor have a command line), and by
465 <function>sd_bus_creds_get_audit_session_id()</function> and
466 <function>sd_bus_creds_get_audit_login_uid()</function> when
467 the process is not part of an audit session, and
468 <function>sd_bus_creds_get_tty()</function> if the process has
475 <term><constant>-EINVAL</constant></term>
477 <listitem><para>Specified pointer parameter is <constant>NULL</constant>.
482 <term><constant>-ENOMEM</constant></term>
484 <listitem><para>Memory allocation failed.</para></listitem>
492 <para><function>sd_bus_creds_get_pid()</function> and the other
493 functions described here are available as a shared library, which
494 can be compiled and linked to with the
495 <constant>libelogind</constant> <citerefentry
496 project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
501 <title>See Also</title>
504 <citerefentry><refentrytitle>elogind</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
505 <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
506 <citerefentry><refentrytitle>sd_bus_creds_new_from_pid</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
507 <citerefentry project='man-pages'><refentrytitle>fork</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
508 <citerefentry project='man-pages'><refentrytitle>execve</refentrytitle><manvolnum>2</manvolnum></citerefentry>,
509 <citerefentry project='man-pages'><refentrytitle>credentials</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
510 <citerefentry project='man-pages'><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
511 <citerefentry project='man-pages'><refentrytitle>proc</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
512 <citerefentry><refentrytitle>elogind.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>