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"-//OASIS//DTD DocBook XML V4.2//EN"
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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
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24 <refentry id=
"sd_bus_creds_new_from_pid">
27 <title>sd_bus_creds_new_from_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_new_from_pid
</refentrytitle>
42 <manvolnum>3</manvolnum>
46 <refname>sd_bus_creds_new_from_pid
</refname>
47 <refname>sd_bus_creds_get_mask
</refname>
48 <refname>sd_bus_creds_get_augmented_mask
</refname>
49 <refname>sd_bus_creds_ref
</refname>
50 <refname>sd_bus_creds_unref
</refname>
52 <refpurpose>Retrieve credentials object for the specified PID
</refpurpose>
57 <funcsynopsisinfo>#include
<systemd/sd-bus.h
></funcsynopsisinfo>
60 <funcdef>int
<function>sd_bus_creds_new_from_pid
</function></funcdef>
61 <paramdef>pid_t
<parameter>pid
</parameter></paramdef>
62 <paramdef>uint64_t
<parameter>creds_mask
</parameter></paramdef>
63 <paramdef>sd_bus_creds **
<parameter>ret
</parameter></paramdef>
67 <funcdef>uint64_t
<function>sd_bus_creds_get_mask
</function></funcdef>
68 <paramdef>const sd_bus_creds *
<parameter>c
</parameter></paramdef>
72 <funcdef>uint64_t
<function>sd_bus_creds_get_augmented_mask
</function></funcdef>
73 <paramdef>const sd_bus_creds *
<parameter>c
</parameter></paramdef>
77 <funcdef>sd_bus_creds *
<function>sd_bus_creds_ref
</function></funcdef>
78 <paramdef>sd_bus_creds *
<parameter>c
</parameter></paramdef>
82 <funcdef>sd_bus_creds *
<function>sd_bus_creds_unref
</function></funcdef>
83 <paramdef>sd_bus_creds *
<parameter>c
</parameter></paramdef>
88 <constant>SD_BUS_CREDS_PID
</constant>,
89 <constant>SD_BUS_CREDS_PPID
</constant>,
90 <constant>SD_BUS_CREDS_TID
</constant>,
91 <constant>SD_BUS_CREDS_UID
</constant>,
92 <constant>SD_BUS_CREDS_EUID
</constant>,
93 <constant>SD_BUS_CREDS_SUID
</constant>,
94 <constant>SD_BUS_CREDS_FSUID
</constant>,
95 <constant>SD_BUS_CREDS_GID
</constant>,
96 <constant>SD_BUS_CREDS_EGID
</constant>,
97 <constant>SD_BUS_CREDS_SGID
</constant>,
98 <constant>SD_BUS_CREDS_FSGID
</constant>,
99 <constant>SD_BUS_CREDS_SUPPLEMENTARY_GIDS
</constant>,
100 <constant>SD_BUS_CREDS_COMM
</constant>,
101 <constant>SD_BUS_CREDS_TID_COMM
</constant>,
102 <constant>SD_BUS_CREDS_EXE
</constant>,
103 <constant>SD_BUS_CREDS_CMDLINE
</constant>,
104 <constant>SD_BUS_CREDS_CGROUP
</constant>,
105 <constant>SD_BUS_CREDS_UNIT
</constant>,
106 <constant>SD_BUS_CREDS_SLICE
</constant>,
107 <constant>SD_BUS_CREDS_USER_UNIT
</constant>,
108 <constant>SD_BUS_CREDS_USER_SLICE
</constant>,
109 <constant>SD_BUS_CREDS_SESSION
</constant>,
110 <constant>SD_BUS_CREDS_OWNER_UID
</constant>,
111 <constant>SD_BUS_CREDS_EFFECTIVE_CAPS
</constant>,
112 <constant>SD_BUS_CREDS_PERMITTED_CAPS
</constant>,
113 <constant>SD_BUS_CREDS_INHERITABLE_CAPS
</constant>,
114 <constant>SD_BUS_CREDS_BOUNDING_CAPS
</constant>,
115 <constant>SD_BUS_CREDS_SELINUX_CONTEXT
</constant>,
116 <constant>SD_BUS_CREDS_AUDIT_SESSION_ID
</constant>,
117 <constant>SD_BUS_CREDS_AUDIT_LOGIN_UID
</constant>,
118 <constant>SD_BUS_CREDS_TTY
</constant>,
119 <constant>SD_BUS_CREDS_UNIQUE_NAME
</constant>,
120 <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES
</constant>,
121 <constant>SD_BUS_CREDS_DESCRIPTION
</constant>,
122 <constant>SD_BUS_CREDS_AUGMENT
</constant>,
123 <constant>_SD_BUS_CREDS_ALL
</constant>
128 <title>Description
</title>
130 <para><function>sd_bus_creds_new_from_pid()
</function> creates a
131 new credentials object and fills it with information about the
132 process
<parameter>pid
</parameter>. The pointer to this object
133 will be stored in
<parameter>ret
</parameter> pointer. Note that
134 credential objects may also be created and retrieved via
135 <citerefentry><refentrytitle>sd_bus_get_name_creds
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
136 <citerefentry><refentrytitle>sd_bus_get_owner_creds
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
138 <citerefentry><refentrytitle>sd_bus_message_get_creds
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
140 <para>The information that will be stored is determined by
141 <parameter>creds_mask
</parameter>. It may contain a subset of ORed
142 constants
<constant>SD_BUS_CREDS_PID
</constant>,
143 <constant>SD_BUS_CREDS_PPID
</constant>,
144 <constant>SD_BUS_CREDS_TID
</constant>,
145 <constant>SD_BUS_CREDS_UID
</constant>,
146 <constant>SD_BUS_CREDS_EUID
</constant>,
147 <constant>SD_BUS_CREDS_SUID
</constant>,
148 <constant>SD_BUS_CREDS_FSUID
</constant>,
149 <constant>SD_BUS_CREDS_GID
</constant>,
150 <constant>SD_BUS_CREDS_EGID
</constant>,
151 <constant>SD_BUS_CREDS_SGID
</constant>,
152 <constant>SD_BUS_CREDS_FSGID
</constant>,
153 <constant>SD_BUS_CREDS_SUPPLEMENTARY_GIDS
</constant>,
154 <constant>SD_BUS_CREDS_COMM
</constant>,
155 <constant>SD_BUS_CREDS_TID_COMM
</constant>,
156 <constant>SD_BUS_CREDS_EXE
</constant>,
157 <constant>SD_BUS_CREDS_CMDLINE
</constant>,
158 <constant>SD_BUS_CREDS_CGROUP
</constant>,
159 <constant>SD_BUS_CREDS_UNIT
</constant>,
160 <constant>SD_BUS_CREDS_SLICE
</constant>,
161 <constant>SD_BUS_CREDS_USER_UNIT
</constant>,
162 <constant>SD_BUS_CREDS_USER_SLICE
</constant>,
163 <constant>SD_BUS_CREDS_SESSION
</constant>,
164 <constant>SD_BUS_CREDS_OWNER_UID
</constant>,
165 <constant>SD_BUS_CREDS_EFFECTIVE_CAPS
</constant>,
166 <constant>SD_BUS_CREDS_PERMITTED_CAPS
</constant>,
167 <constant>SD_BUS_CREDS_INHERITABLE_CAPS
</constant>,
168 <constant>SD_BUS_CREDS_BOUNDING_CAPS
</constant>,
169 <constant>SD_BUS_CREDS_SELINUX_CONTEXT
</constant>,
170 <constant>SD_BUS_CREDS_AUDIT_SESSION_ID
</constant>,
171 <constant>SD_BUS_CREDS_AUDIT_LOGIN_UID
</constant>,
172 <constant>SD_BUS_CREDS_TTY
</constant>,
173 <constant>SD_BUS_CREDS_UNIQUE_NAME
</constant>,
174 <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES
</constant>,
175 <constant>SD_BUS_CREDS_DESCRIPTION
</constant>. Use the special
176 value
<constant>_SD_BUS_CREDS_ALL
</constant> to request all
177 supported fields. The
<constant>SD_BUS_CREDS_AUGMENT
</constant>
178 may not be ORed into the mask for invocations of
179 <function>sd_bus_creds_new_from_pid()
</function>.
</para>
181 <para>Fields can be retrieved from the credentials object using
182 <citerefentry><refentrytitle>sd_bus_creds_get_pid
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
183 and other functions which correspond directly to the constants
186 <para>A mask of fields which were actually successfully retrieved
187 can be retrieved with
188 <function>sd_bus_creds_get_mask()
</function>. If the credentials
189 object was created with
190 <function>sd_bus_creds_new_from_pid()
</function>, this will be a
191 subset of fields requested in
<parameter>creds_mask
</parameter>.
194 <para>Similar to
<function>sd_bus_creds_get_mask()
</function> the
195 function
<function>sd_bus_creds_get_augmented_mask()
</function>
196 returns a bitmask of field constants. The mask indicates which
197 credential fields have been retrieved in a non-atomic fashion. For
198 credential objects created via
199 <function>sd_bus_creds_new_from_pid()
</function> this mask will be
200 identical to the mask returned by
201 <function>sd_bus_creds_get_mask()
</function>. However, for
202 credential objects retrieved via
203 <function>sd_bus_get_name_creds()
</function> this mask will be set
204 for the credential fields that could not be determined atomically
205 at peer connection time, and which were later added by reading
206 augmenting credential data from
207 <filename>/proc
</filename>. Similar, for credential objects
208 retrieved via
<function>sd_bus_get_owner_creds()
</function> the
209 mask is set for the fields that could not be determined atomically
210 at bus creation time, but have been augmented. Similar, for
211 credential objects retrieved via
212 <function>sd_bus_message_get_creds()
</function> the mask is set
213 for the fields that could not be determined atomically at message
214 send time, but have been augmented. The mask returned by
215 <function>sd_bus_creds_get_augmented_mask()
</function> is always a
216 subset of (or identical to) the mask returned by
217 <function>sd_bus_creds_get_mask()
</function> for the same
218 object. The latter call hence returns all credential fields
219 available in the credential object, the former then marks the
220 subset of those that have been augmented. Note that augmented
221 fields are unsuitable for authorization decisions as they may be
222 retrieved at different times, thus being subject to races. Hence
223 augmented fields should be used exclusively for informational
227 <para><function>sd_bus_creds_ref()
</function> creates a new
228 reference to the credentials object
<parameter>c
</parameter>. This
229 object will not be destroyed until
230 <function>sd_bus_creds_unref()
</function> has been called as many
231 times plus once more. Once the reference count has dropped to zero,
232 <parameter>c
</parameter> cannot be used anymore, so further
233 calls to
<function>sd_bus_creds_ref(c)
</function> or
234 <function>sd_bus_creds_unref(c)
</function> are illegal.
</para>
236 <para><function>sd_bus_creds_unref()
</function> destroys a reference
237 to
<parameter>c
</parameter>.
</para>
241 <title>Return Value
</title>
243 <para>On success,
<function>sd_bus_creds_new_from_pid()
</function>
244 returns
0 or a positive integer. On failure, it returns a negative
245 errno-style error code.
</para>
247 <para><function>sd_bus_creds_get_mask()
</function> returns the
248 mask of successfully acquired fields.
</para>
250 <para><function>sd_bus_creds_get_augmented_mask()
</function>
251 returns the mask of fields that have been augmented from data in
252 <filename>/proc
</filename>, and are thus not suitable for
253 authorization decisions.
</para>
255 <para><function>sd_bus_creds_ref()
</function> always returns the
258 <para><function>sd_bus_creds_unref()
</function> always returns
259 <constant>NULL
</constant>.
</para>
263 <title>Reference ownership
</title>
265 <para>Function
<function>sd_bus_creds_new_from_pid()
</function>
266 creates a new object and the caller owns the sole reference. When
267 not needed anymore, this reference should be destroyed with
268 <citerefentry><refentrytitle>sd_bus_creds_unref
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
273 <title>Errors
</title>
275 <para>Returned errors may indicate the following problems:
</para>
280 <term><constant>-ESRCH
</constant></term>
282 <listitem><para>Specified
<parameter>pid
</parameter> could not
283 be found.
</para></listitem>
287 <term><constant>-EINVAL
</constant></term>
289 <listitem><para>Specified parameter is invalid
290 (
<constant>NULL
</constant> in case of output
291 parameters).
</para></listitem>
295 <term><constant>-ENOMEM
</constant></term>
297 <listitem><para>Memory allocation failed.
</para></listitem>
301 <term><constant>-EOPNOTSUPP
</constant></term>
303 <listitem><para>One of the requested fields is unknown to the local system.
</para></listitem>
311 <para><function>sd_bus_creds_new_from_pid()
</function> and the
312 other calls described here are available as a shared library,
313 which can be compiled and linked to with the
314 <constant>libsystemd
</constant> <citerefentry
315 project='die-net'
><refentrytitle>pkg-config
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
320 <title>See Also
</title>
323 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
324 <citerefentry><refentrytitle>sd-bus
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
325 <citerefentry><refentrytitle>sd_bus_creds_get_pid
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
326 <citerefentry><refentrytitle>sd_bus_get_name_creds
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
327 <citerefentry><refentrytitle>sd_bus_get_owner_creds
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
328 <citerefentry><refentrytitle>sd_bus_message_get_creds
</refentrytitle><manvolnum>3</manvolnum></citerefentry>