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<refentry id="sd_bus_creds_new_from_pid" conditional="ENABLE_KDBUS">

  <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_ref</refname>
    <refname>sd_bus_creds_unref</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>const 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>
    </funcsynopsis>

    <para>
      <constant>SD_BUS_CREDS_PID</constant>,
      <constant>SD_BUS_CREDS_PID_STARTTIME</constant>,
      <constant>SD_BUS_CREDS_TID</constant>,
      <constant>SD_BUS_CREDS_UID</constant>,
      <constant>SD_BUS_CREDS_GID</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_USER_UNIT</constant>,
      <constant>SD_BUS_CREDS_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_UNIQUE_NAME</constant>,
      <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</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>. This pointer to this object will
    be stored in <parameter>ret</parameter> pointer.</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_PID_STARTTIME</constant>,
    <constant>SD_BUS_CREDS_TID</constant>,
    <constant>SD_BUS_CREDS_UID</constant>,
    <constant>SD_BUS_CREDS_GID</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_USER_UNIT</constant>,
    <constant>SD_BUS_CREDS_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_UNIQUE_NAME</constant>,
    <constant>SD_BUS_CREDS_WELL_KNOWN_NAMES</constant>,
    or <constant>_SD_BUS_CREDS_ALL</constant> to indicate
    all known fields.</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 sucessfully set
    (acquired from <filename>/proc</filename>, etc.) 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><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 futher
    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>
  </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_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><varname>-ESRCH</varname></term>

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

      <varlistentry>
        <term><varname>-EINVAL</varname></term>

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

      <varlistentry>
        <term><varname>-ENOMEM</varname></term>

        <listitem><para>Memory allocation failed.</para></listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Notes</title>

    <para><function>sd_bus_creds_new_from_pid()</function> is
    available as a shared library, which can be compiled and linked to
    with the
    <constant>libsystemd</constant> <citerefentry><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_ref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_unref</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_pid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_pid_starttime</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_tid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_uid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_gid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_comm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_tid_comm</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_exe</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_cmdline</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_cgroup</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_unit</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_user_unit</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_slice</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_owner_uid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_has_effective_cap</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_has_permitted_cap</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_has_inheritable_cap</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_has_bounding_cap</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_selinux_context</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_audit_session_id</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_audit_login_uid</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_unique_name</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>sd_bus_creds_get_well_known_names</refentrytitle><manvolnum>3</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>