man/sd_bus_creds_new_from_pid.xml

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   8
   9 <refentry id="sd_bus_creds_new_from_pid" xmlns:xi="http://www.w3.org/2001/XInclude">
  10
  11   <refentryinfo>
  12     <title>sd_bus_creds_new_from_pid</title>
  13     <productname>systemd</productname>
  14   </refentryinfo>
  15
  16   <refmeta>
  17     <refentrytitle>sd_bus_creds_new_from_pid</refentrytitle>
  18     <manvolnum>3</manvolnum>
  19   </refmeta>
  20
  21   <refnamediv>
  22     <refname>sd_bus_creds_new_from_pid</refname>
  23     <refname>sd_bus_creds_get_mask</refname>
  24     <refname>sd_bus_creds_get_augmented_mask</refname>
  25     <refname>sd_bus_creds_ref</refname>
  26     <refname>sd_bus_creds_unref</refname>
  27     <refname>sd_bus_creds_unrefp</refname>
  28
  29     <refpurpose>Retrieve credentials object for the specified PID</refpurpose>
  30   </refnamediv>
  31
  32   <refsynopsisdiv>
  33     <funcsynopsis>
  34       <funcsynopsisinfo>#include &lt;systemd/sd-bus.h&gt;</funcsynopsisinfo>
  35
  36       <funcprototype>
  37         <funcdef>int <function>sd_bus_creds_new_from_pid</function></funcdef>
  38         <paramdef>pid_t <parameter>pid</parameter></paramdef>
  39         <paramdef>uint64_t <parameter>creds_mask</parameter></paramdef>
  40         <paramdef>sd_bus_creds **<parameter>ret</parameter></paramdef>
  41       </funcprototype>
  42
  43       <funcprototype>
  44         <funcdef>uint64_t <function>sd_bus_creds_get_mask</function></funcdef>
  45         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  46       </funcprototype>
  47
  48       <funcprototype>
  49         <funcdef>uint64_t <function>sd_bus_creds_get_augmented_mask</function></funcdef>
  50         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  51       </funcprototype>
  52
  53       <funcprototype>
  54         <funcdef>sd_bus_creds *<function>sd_bus_creds_ref</function></funcdef>
  55         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  56       </funcprototype>
  57
  58       <funcprototype>
  59         <funcdef>sd_bus_creds *<function>sd_bus_creds_unref</function></funcdef>
  60         <paramdef>sd_bus_creds *<parameter>c</parameter></paramdef>
  61       </funcprototype>
  62
  63       <funcprototype>
  64         <funcdef>void <function>sd_bus_creds_unrefp</function></funcdef>
  65         <paramdef>sd_bus_creds **<parameter>c</parameter></paramdef>
  66       </funcprototype>
  67     </funcsynopsis>
  68
  69     <para>
  70       <constant>SD_BUS_CREDS_PID</constant>,
  71       <constant>SD_BUS_CREDS_PPID</constant>,
  72       <constant>SD_BUS_CREDS_TID</constant>,
  73       <constant>SD_BUS_CREDS_UID</constant>,
  74       <constant>SD_BUS_CREDS_EUID</constant>,
  75       <constant>SD_BUS_CREDS_SUID</constant>,
  76       <constant>SD_BUS_CREDS_FSUID</constant>,
  77       <constant>SD_BUS_CREDS_GID</constant>,
  78       <constant>SD_BUS_CREDS_EGID</constant>,
  79       <constant>SD_BUS_CREDS_SGID</constant>,
  80       <constant>SD_BUS_CREDS_FSGID</constant>,
  81       <constant>SD_BUS_CREDS_SUPPLEMENTARY_GIDS</constant>,
  82       <constant>SD_BUS_CREDS_COMM</constant>,
  83       <constant>SD_BUS_CREDS_TID_COMM</constant>,
  84       <constant>SD_BUS_CREDS_EXE</constant>,
  85       <constant>SD_BUS_CREDS_CMDLINE</constant>,
  86       <constant>SD_BUS_CREDS_CGROUP</constant>,
  87       <constant>SD_BUS_CREDS_UNIT</constant>,
  88       <constant>SD_BUS_CREDS_SLICE</constant>,
  89       <constant>SD_BUS_CREDS_USER_UNIT</constant>,
  90       <constant>SD_BUS_CREDS_USER_SLICE</constant>,
  91       <constant>SD_BUS_CREDS_SESSION</constant>,
  92       <constant>SD_BUS_CREDS_OWNER_UID</constant>,
  93       <constant>SD_BUS_CREDS_EFFECTIVE_CAPS</constant>,
  94       <constant>SD_BUS_CREDS_PERMITTED_CAPS</constant>,
  95       <constant>SD_BUS_CREDS_INHERITABLE_CAPS</constant>,
  96       <constant>SD_BUS_CREDS_BOUNDING_CAPS</constant>,
  97       <constant>SD_BUS_CREDS_SELINUX_CONTEXT</constant>,
  98       <constant>SD_BUS_CREDS_AUDIT_SESSION_ID</constant>,
  99       <constant>SD_BUS_CREDS_AUDIT_LOGIN_UID</constant>,
 100       <constant>SD_BUS_CREDS_TTY</constant>,
 101       <constant>SD_BUS_CREDS_UNIQUE_NAME</constant>,
 102       <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant>,
 103       <constant>SD_BUS_CREDS_DESCRIPTION</constant>,
 104       <constant>SD_BUS_CREDS_AUGMENT</constant>,
 105       <constant>_SD_BUS_CREDS_ALL</constant>
 106     </para>
 107   </refsynopsisdiv>
 108
 109   <refsect1>
 110     <title>Description</title>
 111
 112     <para><function>sd_bus_creds_new_from_pid()</function> creates a
 113     new credentials object and fills it with information about the
 114     process <parameter>pid</parameter>. The pointer to this object
 115     will be stored in the <parameter>ret</parameter> pointer. Note that
 116     credential objects may also be created and retrieved via
 117     <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 118     <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 119     and
 120     <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
 121
 122     <para>The information that will be stored is determined by
 123     <parameter>creds_mask</parameter>. It may contain a subset of ORed
 124     constants <constant>SD_BUS_CREDS_PID</constant>,
 125     <constant>SD_BUS_CREDS_PPID</constant>,
 126     <constant>SD_BUS_CREDS_TID</constant>,
 127     <constant>SD_BUS_CREDS_UID</constant>,
 128     <constant>SD_BUS_CREDS_EUID</constant>,
 129     <constant>SD_BUS_CREDS_SUID</constant>,
 130     <constant>SD_BUS_CREDS_FSUID</constant>,
 131     <constant>SD_BUS_CREDS_GID</constant>,
 132     <constant>SD_BUS_CREDS_EGID</constant>,
 133     <constant>SD_BUS_CREDS_SGID</constant>,
 134     <constant>SD_BUS_CREDS_FSGID</constant>,
 135     <constant>SD_BUS_CREDS_SUPPLEMENTARY_GIDS</constant>,
 136     <constant>SD_BUS_CREDS_COMM</constant>,
 137     <constant>SD_BUS_CREDS_TID_COMM</constant>,
 138     <constant>SD_BUS_CREDS_EXE</constant>,
 139     <constant>SD_BUS_CREDS_CMDLINE</constant>,
 140     <constant>SD_BUS_CREDS_CGROUP</constant>,
 141     <constant>SD_BUS_CREDS_UNIT</constant>,
 142     <constant>SD_BUS_CREDS_SLICE</constant>,
 143     <constant>SD_BUS_CREDS_USER_UNIT</constant>,
 144     <constant>SD_BUS_CREDS_USER_SLICE</constant>,
 145     <constant>SD_BUS_CREDS_SESSION</constant>,
 146     <constant>SD_BUS_CREDS_OWNER_UID</constant>,
 147     <constant>SD_BUS_CREDS_EFFECTIVE_CAPS</constant>,
 148     <constant>SD_BUS_CREDS_PERMITTED_CAPS</constant>,
 149     <constant>SD_BUS_CREDS_INHERITABLE_CAPS</constant>,
 150     <constant>SD_BUS_CREDS_BOUNDING_CAPS</constant>,
 151     <constant>SD_BUS_CREDS_SELINUX_CONTEXT</constant>,
 152     <constant>SD_BUS_CREDS_AUDIT_SESSION_ID</constant>,
 153     <constant>SD_BUS_CREDS_AUDIT_LOGIN_UID</constant>,
 154     <constant>SD_BUS_CREDS_TTY</constant>,
 155     <constant>SD_BUS_CREDS_UNIQUE_NAME</constant>,
 156     <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant>, and
 157     <constant>SD_BUS_CREDS_DESCRIPTION</constant>. Use the special
 158     value <constant>_SD_BUS_CREDS_ALL</constant> to request all
 159     supported fields. The <constant>SD_BUS_CREDS_AUGMENT</constant>
 160     constant may not be ORed into the mask for invocations of
 161     <function>sd_bus_creds_new_from_pid()</function>.</para>
 162
 163     <para>Fields can be retrieved from the credentials object using
 164     <citerefentry><refentrytitle>sd_bus_creds_get_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 165     and other functions which correspond directly to the constants
 166     listed above.</para>
 167
 168     <para>A mask of fields which were actually successfully retrieved
 169     can be retrieved with
 170     <function>sd_bus_creds_get_mask()</function>. If the credentials
 171     object was created with
 172     <function>sd_bus_creds_new_from_pid()</function>, this will be a
 173     subset of fields requested in <parameter>creds_mask</parameter>.
 174     </para>
 175
 176     <para>Similar to <function>sd_bus_creds_get_mask()</function>, the
 177     function <function>sd_bus_creds_get_augmented_mask()</function>
 178     returns a bitmask of field constants. The mask indicates which
 179     credential fields have been retrieved in a non-atomic fashion. For
 180     credential objects created via
 181     <function>sd_bus_creds_new_from_pid()</function>, this mask will be
 182     identical to the mask returned by
 183     <function>sd_bus_creds_get_mask()</function>. However, for
 184     credential objects retrieved via
 185     <function>sd_bus_get_name_creds()</function>, this mask will be set
 186     for the credential fields that could not be determined atomically
 187     at peer connection time, and which were later added by reading
 188     augmenting credential data from
 189     <filename>/proc</filename>. Similarly, for credential objects
 190     retrieved via <function>sd_bus_get_owner_creds()</function>, the
 191     mask is set for the fields that could not be determined atomically
 192     at bus creation time, but have been augmented. Similarly, for
 193     credential objects retrieved via
 194     <function>sd_bus_message_get_creds()</function>, the mask is set
 195     for the fields that could not be determined atomically at message
 196     sending time, but have been augmented. The mask returned by
 197     <function>sd_bus_creds_get_augmented_mask()</function> is always a
 198     subset of (or identical to) the mask returned by
 199     <function>sd_bus_creds_get_mask()</function> for the same
 200     object. The latter call hence returns all credential fields
 201     available in the credential object, the former then marks the
 202     subset of those that have been augmented. Note that augmented
 203     fields are unsuitable for authorization decisions, as they may be
 204     retrieved at different times, thus being subject to races. Hence,
 205     augmented fields should be used exclusively for informational
 206     purposes.
 207     </para>
 208
 209     <para><function>sd_bus_creds_ref()</function> creates a new
 210     reference to the credentials object <parameter>c</parameter>. This
 211     object will not be destroyed until
 212     <function>sd_bus_creds_unref()</function> has been called as many
 213     times plus once more. Once the reference count has dropped to zero,
 214     <parameter>c</parameter> cannot be used anymore, so further
 215     calls to <function>sd_bus_creds_ref(c)</function> or
 216     <function>sd_bus_creds_unref(c)</function> are illegal.</para>
 217
 218     <para><function>sd_bus_creds_unref()</function> destroys a reference
 219     to <parameter>c</parameter>.</para>
 220
 221     <para><function>sd_bus_creds_unrefp()</function> is similar to
 222     <function>sd_bus_creds_unref()</function> but takes a pointer to a
 223     pointer to an <type>sd_bus_creds</type> object. This call is useful in
 224     conjunction with GCC's and LLVM's <ulink
 225     url="https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html">Clean-up
 226     Variable Attribute</ulink>. Note that this function is defined as
 227     inline function.</para>
 228
 229     <para><function>sd_bus_creds_ref()</function>,
 230     <function>sd_bus_creds_unref()</function> and
 231     <function>sd_bus_creds_unrefp()</function> execute no operation if
 232     the passed in bus credentials object is
 233     <constant>NULL</constant>.</para>
 234
 235   </refsect1>
 236
 237   <refsect1>
 238     <title>Return Value</title>
 239
 240     <para>On success, <function>sd_bus_creds_new_from_pid()</function>
 241     returns 0 or a positive integer. On failure, it returns a negative
 242     errno-style error code.</para>
 243
 244     <para><function>sd_bus_creds_get_mask()</function> returns the
 245     mask of successfully acquired fields.</para>
 246
 247     <para><function>sd_bus_creds_get_augmented_mask()</function>
 248     returns the mask of fields that have been augmented from data in
 249     <filename>/proc</filename>, and are thus not suitable for
 250     authorization decisions.</para>
 251
 252     <para><function>sd_bus_creds_ref()</function> always returns the
 253     argument.</para>
 254
 255     <para><function>sd_bus_creds_unref()</function> always returns
 256     <constant>NULL</constant>.</para>
 257   </refsect1>
 258
 259   <refsect1>
 260     <title>Reference ownership</title>
 261
 262     <para>Function <function>sd_bus_creds_new_from_pid()</function>
 263     creates a new object and the caller owns the sole reference. When
 264     not needed anymore, this reference should be destroyed with
 265     <citerefentry><refentrytitle>sd_bus_creds_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
 266     </para>
 267   </refsect1>
 268
 269   <refsect1>
 270     <title>Errors</title>
 271
 272     <para>Returned errors may indicate the following problems:</para>
 273
 274     <variablelist>
 275
 276       <varlistentry>
 277         <term><constant>-ESRCH</constant></term>
 278
 279         <listitem><para>Specified <parameter>pid</parameter> could not
 280         be found.</para></listitem>
 281       </varlistentry>
 282
 283       <varlistentry>
 284         <term><constant>-EINVAL</constant></term>
 285
 286         <listitem><para>Specified parameter is invalid
 287         (<constant>NULL</constant> in case of output
 288         parameters).</para></listitem>
 289       </varlistentry>
 290
 291       <varlistentry>
 292         <term><constant>-ENOMEM</constant></term>
 293
 294         <listitem><para>Memory allocation failed.</para></listitem>
 295       </varlistentry>
 296
 297       <varlistentry>
 298         <term><constant>-EOPNOTSUPP</constant></term>
 299
 300         <listitem><para>One of the requested fields is unknown to the local system.</para></listitem>
 301       </varlistentry>
 302     </variablelist>
 303   </refsect1>
 304
 305   <xi:include href="libsystemd-pkgconfig.xml" />
 306
 307   <refsect1>
 308     <title>See Also</title>
 309
 310     <para>
 311       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 312       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 313       <citerefentry><refentrytitle>sd_bus_creds_get_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 314       <citerefentry><refentrytitle>sd_bus_get_name_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 315       <citerefentry><refentrytitle>sd_bus_get_owner_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 316       <citerefentry><refentrytitle>sd_bus_message_get_creds</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 317     </para>
 318   </refsect1>
 319
 320 </refentry>