linux-pam/doc/man/pam_set_data.3.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
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<refentry id='pam_set_data'>

  <refmeta>
    <refentrytitle>pam_set_data</refentrytitle>
    <manvolnum>3</manvolnum>
    <refmiscinfo class='setdesc'>Linux-PAM Manual</refmiscinfo>
  </refmeta>

  <refnamediv id='pam_set_data-name'>
    <refname>pam_set_data</refname>
    <refpurpose>
       set module internal data
    </refpurpose>
  </refnamediv>


<!-- body begins here -->

  <refsynopsisdiv>

   <funcsynopsis id="pam_set_data-synopsis">
     <funcsynopsisinfo>#include &lt;security/pam_modules.h&gt;</funcsynopsisinfo>
     <funcprototype>
       <funcdef>int <function>pam_set_data</function></funcdef>
       <paramdef>pam_handle_t *<parameter>pamh</parameter></paramdef>
       <paramdef>const char *<parameter>module_data_name</parameter></paramdef>
       <paramdef>void *<parameter>data</parameter></paramdef>
       <paramdef>void <parameter>(*cleanup)(pam_handle_t *pamh, void *data, int error_status)</parameter></paramdef>
     </funcprototype>
   </funcsynopsis>

  </refsynopsisdiv>


  <refsect1 id="pam_set_data-description">
    <title>DESCRIPTION</title>
    <para>
      The <function>pam_set_data</function> function associates a pointer
      to an object with the (hopefully) unique string
      <emphasis>module_data_name</emphasis> in the PAM context specified
      by the <emphasis>pamh</emphasis> argument.
    </para>

    <para>
      PAM modules may be dynamically loadable objects. In general such files
      should not contain <emphasis>static</emphasis> variables. This function
      and its counterpart
      <citerefentry>
        <refentrytitle>pam_get_data</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      provide a mechanism for a module to associate some data with
      the handle <emphasis>pamh</emphasis>. Typically a module will call the
      <function>pam_set_data</function> function to register some data
       under a (hopefully) unique <emphasis>module_data_name</emphasis>.
       The data is available for use by other modules too but
       <emphasis>not</emphasis> by an application. Since this functions
       stores only a pointer to the <emphasis>data</emphasis>, the module
       should not modify or free the content of it.
    </para>

    <para>
      The function <function>cleanup()</function> is associated with the
      <emphasis>data</emphasis> and, if non-NULL, it is called when this
      data is over-written or following a call to
      <citerefentry>
        <refentrytitle>pam_end</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>.
    </para>

    <para>
      The <emphasis>error_status</emphasis> argument is used to indicate
      to the module the sort of action it is to take in cleaning this data
      item. As an example, Kerberos creates a ticket file during the
      authentication phase, this file might be associated with a data item.
      When
      <citerefentry>
        <refentrytitle>pam_end</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>
      is called by the module, the <emphasis>error_status</emphasis>
      carries the return value of the
      <citerefentry>
        <refentrytitle>pam_authenticate</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>
     or other <emphasis>libpam</emphasis> function as appropriate. Based
     on this value the Kerberos module may choose to delete the ticket file
     (<emphasis>authentication failure</emphasis>) or leave it in place.
   </para>

   <para>
     The <emphasis>error_status</emphasis> may have been logically
     OR'd with either of the following two values:
   </para>

    <variablelist>
      <varlistentry>
        <term>PAM_DATA_REPLACE</term>
        <listitem>
          <para>
            When a data item is being replaced (through a second call to
            <function>pam_set_data</function>) this mask is used.
            Otherwise, the call is assumed to be from
            <citerefentry>
              <refentrytitle>pam_end</refentrytitle><manvolnum>3</manvolnum>
            </citerefentry>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term>PAM_DATA_SILENT</term>
        <listitem>
          <para>
            Which indicates that the process would prefer to perform the
            <function>cleanup()</function> quietly. That is, discourages
            logging/messages to the user.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id="pam_set_data-return_values">
    <title>RETURN VALUES</title>
    <variablelist>
      <varlistentry>
        <term>PAM_BUF_ERR</term>
        <listitem>
           <para>
              Memory buffer error.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_SUCCESS</term>
        <listitem>
           <para>
             Data was successful stored.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_SYSTEM_ERR</term>
        <listitem>
           <para>
             A NULL pointer was submitted as PAM handle or the
             function was called by an application.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id="pam_set_data-see_also">
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
        <refentrytitle>pam_end</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>pam_get_data</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>pam_strerror</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>
    </para>
  </refsect1>

</refentry>