summaryrefslogtreecommitdiff
path: root/man/sd_bus_creds_new_from_pid.xml
blob: ed26f4418b55fb7cbc0ff4347eb4142aba8429b3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
<?xml version='1.0'?> <!--*- Mode: nxml; nxml-child-indent: 2; indent-tabs-mode: nil -*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<!--
  SPDX-License-Identifier: LGPL-2.1+

  This file is part of systemd.

  Copyright 2014 Zbigniew Jędrzejewski-Szmek
-->

<refentry id="sd_bus_creds_new_from_pid">

  <refentryinfo>
    <title>sd_bus_creds_new_from_pid</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>A monkey with a typewriter</contrib>
        <firstname>Zbigniew</firstname>
        <surname>Jędrzejewski-Szmek</surname>
        <email>zbyszek@in.waw.pl</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>sd_bus_creds_new_from_pid</refentrytitle>
    <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>sd_bus_creds_new_from_pid</refname>
    <refname>sd_bus_creds_get_mask</refname>
    <refname>sd_bus_creds_get_augmented_mask</refname>
    <refname>sd_bus_creds_ref</refname>
    <refname>sd_bus_creds_unref</refname>
    <refname>sd_bus_creds_unrefp</refname>

    <refpurpose>Retrieve credentials object for the specified PID</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <funcsynopsis>
      <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>

      <funcprototype>
        <funcdef>int <function>sd_bus_creds_new_from_pid</function></funcdef>
        <paramdef>pid_t <parameter>pid</parameter></paramdef>
        <paramdef>uint64_t <parameter>creds_mask</parameter></paramdef>
        <paramdef>sd_bus_creds **<parameter>ret</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>uint64_t <function>sd_bus_creds_get_mask</function></funcdef>
        <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>uint64_t <function>sd_bus_creds_get_augmented_mask</function></funcdef>
        <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>sd_bus_creds *<function>sd_bus_creds_ref</function></funcdef>
        <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>sd_bus_creds *<function>sd_bus_creds_unref</function></funcdef>
        <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>void <function>sd_bus_creds_unrefp</function></funcdef>
        <paramdef>sd_bus_creds **<parameter>c</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>

    <para>
      <constant>SD_BUS_CREDS_PID</constant>,
      <constant>SD_BUS_CREDS_PPID</constant>,
      <constant>SD_BUS_CREDS_TID</constant>,
      <constant>SD_BUS_CREDS_UID</constant>,
      <constant>SD_BUS_CREDS_EUID</constant>,
      <constant>SD_BUS_CREDS_SUID</constant>,
      <constant>SD_BUS_CREDS_FSUID</constant>,
      <constant>SD_BUS_CREDS_GID</constant>,
      <constant>SD_BUS_CREDS_EGID</constant>,
      <constant>SD_BUS_CREDS_SGID</constant>,
      <constant>SD_BUS_CREDS_FSGID</constant>,
      <constant>SD_BUS_CREDS_SUPPLEMENTARY_GIDS</constant>,
      <constant>SD_BUS_CREDS_COMM</constant>,
      <constant>SD_BUS_CREDS_TID_COMM</constant>,
      <constant>SD_BUS_CREDS_EXE</constant>,
      <constant>SD_BUS_CREDS_CMDLINE</constant>,
      <constant>SD_BUS_CREDS_CGROUP</constant>,
      <constant>SD_BUS_CREDS_UNIT</constant>,
      <constant>SD_BUS_CREDS_SLICE</constant>,
      <constant>SD_BUS_CREDS_USER_UNIT</constant>,
      <constant>SD_BUS_CREDS_USER_SLICE</constant>,
      <constant>SD_BUS_CREDS_SESSION</constant>,
      <constant>SD_BUS_CREDS_OWNER_UID</constant>,
      <constant>SD_BUS_CREDS_EFFECTIVE_CAPS</constant>,
      <constant>SD_BUS_CREDS_PERMITTED_CAPS</constant>,
      <constant>SD_BUS_CREDS_INHERITABLE_CAPS</constant>,
      <constant>SD_BUS_CREDS_BOUNDING_CAPS</constant>,
      <constant>SD_BUS_CREDS_SELINUX_CONTEXT</constant>,
      <constant>SD_BUS_CREDS_AUDIT_SESSION_ID</constant>,
      <constant>SD_BUS_CREDS_AUDIT_LOGIN_UID</constant>,
      <constant>SD_BUS_CREDS_TTY</constant>,
      <constant>SD_BUS_CREDS_UNIQUE_NAME</constant>,
      <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant>,
      <constant>SD_BUS_CREDS_DESCRIPTION</constant>,
      <constant>SD_BUS_CREDS_AUGMENT</constant>,
      <constant>_SD_BUS_CREDS_ALL</constant>
    </para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><function>sd_bus_creds_new_from_pid()</function> creates a
    new credentials object and fills it with information about the
    process <parameter>pid</parameter>. The pointer to this object
    will be stored in the <parameter>ret</parameter> pointer. Note that
    credential objects may also be created and retrieved via
    <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
    <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
    and
    <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>

    <para>The information that will be stored is determined by
    <parameter>creds_mask</parameter>. It may contain a subset of ORed
    constants <constant>SD_BUS_CREDS_PID</constant>,
    <constant>SD_BUS_CREDS_PPID</constant>,
    <constant>SD_BUS_CREDS_TID</constant>,
    <constant>SD_BUS_CREDS_UID</constant>,
    <constant>SD_BUS_CREDS_EUID</constant>,
    <constant>SD_BUS_CREDS_SUID</constant>,
    <constant>SD_BUS_CREDS_FSUID</constant>,
    <constant>SD_BUS_CREDS_GID</constant>,
    <constant>SD_BUS_CREDS_EGID</constant>,
    <constant>SD_BUS_CREDS_SGID</constant>,
    <constant>SD_BUS_CREDS_FSGID</constant>,
    <constant>SD_BUS_CREDS_SUPPLEMENTARY_GIDS</constant>,
    <constant>SD_BUS_CREDS_COMM</constant>,
    <constant>SD_BUS_CREDS_TID_COMM</constant>,
    <constant>SD_BUS_CREDS_EXE</constant>,
    <constant>SD_BUS_CREDS_CMDLINE</constant>,
    <constant>SD_BUS_CREDS_CGROUP</constant>,
    <constant>SD_BUS_CREDS_UNIT</constant>,
    <constant>SD_BUS_CREDS_SLICE</constant>,
    <constant>SD_BUS_CREDS_USER_UNIT</constant>,
    <constant>SD_BUS_CREDS_USER_SLICE</constant>,
    <constant>SD_BUS_CREDS_SESSION</constant>,
    <constant>SD_BUS_CREDS_OWNER_UID</constant>,
    <constant>SD_BUS_CREDS_EFFECTIVE_CAPS</constant>,
    <constant>SD_BUS_CREDS_PERMITTED_CAPS</constant>,
    <constant>SD_BUS_CREDS_INHERITABLE_CAPS</constant>,
    <constant>SD_BUS_CREDS_BOUNDING_CAPS</constant>,
    <constant>SD_BUS_CREDS_SELINUX_CONTEXT</constant>,
    <constant>SD_BUS_CREDS_AUDIT_SESSION_ID</constant>,
    <constant>SD_BUS_CREDS_AUDIT_LOGIN_UID</constant>,
    <constant>SD_BUS_CREDS_TTY</constant>,
    <constant>SD_BUS_CREDS_UNIQUE_NAME</constant>,
    <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant>, and
    <constant>SD_BUS_CREDS_DESCRIPTION</constant>. Use the special
    value <constant>_SD_BUS_CREDS_ALL</constant> to request all
    supported fields. The <constant>SD_BUS_CREDS_AUGMENT</constant>
    constant may not be ORed into the mask for invocations of
    <function>sd_bus_creds_new_from_pid()</function>.</para>

    <para>Fields can be retrieved from the credentials object using
    <citerefentry><refentrytitle>sd_bus_creds_get_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>
    and other functions which correspond directly to the constants
    listed above.</para>

    <para>A mask of fields which were actually successfully retrieved
    can be retrieved with
    <function>sd_bus_creds_get_mask()</function>. If the credentials
    object was created with
    <function>sd_bus_creds_new_from_pid()</function>, this will be a
    subset of fields requested in <parameter>creds_mask</parameter>.
    </para>

    <para>Similar to <function>sd_bus_creds_get_mask()</function>, the
    function <function>sd_bus_creds_get_augmented_mask()</function>
    returns a bitmask of field constants. The mask indicates which
    credential fields have been retrieved in a non-atomic fashion. For
    credential objects created via
    <function>sd_bus_creds_new_from_pid()</function>, this mask will be
    identical to the mask returned by
    <function>sd_bus_creds_get_mask()</function>. However, for
    credential objects retrieved via
    <function>sd_bus_get_name_creds()</function>, this mask will be set
    for the credential fields that could not be determined atomically
    at peer connection time, and which were later added by reading
    augmenting credential data from
    <filename>/proc</filename>. Similarly, for credential objects
    retrieved via <function>sd_bus_get_owner_creds()</function>, the
    mask is set for the fields that could not be determined atomically
    at bus creation time, but have been augmented. Similarly, for
    credential objects retrieved via
    <function>sd_bus_message_get_creds()</function>, the mask is set
    for the fields that could not be determined atomically at message
    sending time, but have been augmented. The mask returned by
    <function>sd_bus_creds_get_augmented_mask()</function> is always a
    subset of (or identical to) the mask returned by
    <function>sd_bus_creds_get_mask()</function> for the same
    object. The latter call hence returns all credential fields
    available in the credential object, the former then marks the
    subset of those that have been augmented. Note that augmented
    fields are unsuitable for authorization decisions, as they may be
    retrieved at different times, thus being subject to races. Hence,
    augmented fields should be used exclusively for informational
    purposes.
    </para>

    <para><function>sd_bus_creds_ref()</function> creates a new
    reference to the credentials object <parameter>c</parameter>. This
    object will not be destroyed until
    <function>sd_bus_creds_unref()</function> has been called as many
    times plus once more. Once the reference count has dropped to zero,
    <parameter>c</parameter> cannot be used anymore, so further
    calls to <function>sd_bus_creds_ref(c)</function> or
    <function>sd_bus_creds_unref(c)</function> are illegal.</para>

    <para><function>sd_bus_creds_unref()</function> destroys a reference
    to <parameter>c</parameter>.</para>

    <para><function>sd_bus_creds_unrefp()</function> is similar to
    <function>sd_bus_creds_unref()</function> but takes a pointer to a
    pointer to an <type>sd_bus_creds</type> object. This call is useful in
    conjunction with GCC's and LLVM's <ulink
    url="https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html">Clean-up
    Variable Attribute</ulink>. Note that this function is defined as
    inline function.</para>

    <para><function>sd_bus_creds_ref()</function>,
    <function>sd_bus_creds_unref()</function> and
    <function>sd_bus_creds_unrefp()</function> execute no operation if
    the passed in bus credentials object is
    <constant>NULL</constant>.</para>

  </refsect1>

  <refsect1>
    <title>Return Value</title>

    <para>On success, <function>sd_bus_creds_new_from_pid()</function>
    returns 0 or a positive integer. On failure, it returns a negative
    errno-style error code.</para>

    <para><function>sd_bus_creds_get_mask()</function> returns the
    mask of successfully acquired fields.</para>

    <para><function>sd_bus_creds_get_augmented_mask()</function>
    returns the mask of fields that have been augmented from data in
    <filename>/proc</filename>, and are thus not suitable for
    authorization decisions.</para>

    <para><function>sd_bus_creds_ref()</function> always returns the
    argument.</para>

    <para><function>sd_bus_creds_unref()</function> always returns
    <constant>NULL</constant>.</para>
  </refsect1>

  <refsect1>
    <title>Reference ownership</title>

    <para>Function <function>sd_bus_creds_new_from_pid()</function>
    creates a new object and the caller owns the sole reference. When
    not needed anymore, this reference should be destroyed with
    <citerefentry><refentrytitle>sd_bus_creds_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
    </para>
  </refsect1>

  <refsect1>
    <title>Errors</title>

    <para>Returned errors may indicate the following problems:</para>

    <variablelist>

      <varlistentry>
        <term><constant>-ESRCH</constant></term>

        <listitem><para>Specified <parameter>pid</parameter> could not
        be found.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><constant>-EINVAL</constant></term>

        <listitem><para>Specified parameter is invalid
        (<constant>NULL</constant> in case of output
        parameters).</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><constant>-ENOMEM</constant></term>

        <listitem><para>Memory allocation failed.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><constant>-EOPNOTSUPP</constant></term>

        <listitem><para>One of the requested fields is unknown to the local system.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Notes</title>

    <para><function>sd_bus_creds_new_from_pid()</function> and the
    other calls described here are available as a shared library,
    which can be compiled and linked to with the
    <constant>libsystemd</constant> <citerefentry
    project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    file.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>

    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>