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<refentry id="misc_conv">

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

  <refnamediv id="misc_conv-name">
    <refname>misc_conv</refname>
    <refpurpose>text based conversation function</refpurpose>
  </refnamediv>

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  <refsynopsisdiv>
    <funcsynopsis id="misc_conv-synopsis">
      <funcsynopsisinfo>#include &lt;security/pam_misc.h&gt;</funcsynopsisinfo>
      <funcprototype>
        <funcdef>void <function>misc_conv</function></funcdef>
        <paramdef>int <parameter>num_msg</parameter></paramdef>
        <paramdef>const struct pam_message **<parameter>msgm</parameter></paramdef>
        <paramdef>struct pam_response **<parameter>response</parameter></paramdef>
        <paramdef>void *<parameter>appdata_ptr</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1 id='misc_conv-description'>
    <title>DESCRIPTION</title>
    <para>
      The <function>misc_conv</function> function is part of
      <command>libpam_misc</command> and not of the standard
      <command>libpam</command> library. This function will prompt
      the user with the appropriate comments and obtain the appropriate
      inputs as directed by authentication modules.
    </para>
    <para>
      In addition to simply slotting into the appropriate <citerefentry>
      <refentrytitle>pam_conv</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>, this function provides some time-out facilities.
      The function exports five variables that can be used by an
      application programmer to limit the amount of time this conversation
      function will spend waiting for the user to type something. The
      five variabls are as follows:
    </para>
    <variablelist>
      <varlistentry>
        <term><type>time_t</type> <varname>pam_misc_conv_warn_time</varname>;</term>
        <listitem>
          <para>
            This variable contains the <emphasis>time</emphasis> (as
            returned by <citerefentry>
            <refentrytitle>time</refentrytitle><manvolnum>2</manvolnum>
            </citerefentry>) that the user should be first warned that
            the clock is ticking. By default it has the value
            <returnvalue>0</returnvalue>, which indicates that no such
            warning will be given. The application may set its value to
            sometime in the future, but this should be done prior to
            passing control to the <emphasis>Linux-PAM</emphasis> library.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><type>const char *</type><varname>pam_misc_conv_warn_line</varname>;</term>
        <listitem>
          <para>
            Used in conjuction with
            <varname>pam_misc_conv_warn_time</varname>, this variable is
            a pointer to the string that will be displayed when it becomes
            time to warn the user that the timeout is approaching. Its
            default value is a translated version of
            <quote>...Time is running out...</quote>, but this can be
            changed by the application prior to passing control to
            <emphasis>Linux-PAM</emphasis>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><type>time_t</type> <varname>pam_misc_conv_die_time</varname>;</term>
        <listitem>
          <para>
            This variable contains the <emphasis>time</emphasis> (as
            returned by <citerefentry>
            <refentrytitle>time</refentrytitle><manvolnum>2</manvolnum>
            </citerefentry>) that the will time out. By default it has
            the value <returnvalue>0</returnvalue>, which indicates that
            the conversation function will not timeout. The application
            may set its value to sometime in the future, but this should
            be done prior to passing control to the
            <emphasis>Linux-PAM</emphasis> library.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><type>const char *</type><varname>pam_misc_conv_die_line</varname>;</term>
        <listitem>
          <para>
            Used in conjuction with
            <varname>pam_misc_conv_die_time</varname>, this variable is
            a pointer to the string that will be displayed when the
            conversation times out. Its default value is a translated
            version of
            <quote>...Sorry, your time is up!</quote>, but this can be
            changed by the application prior to passing control to
            <emphasis>Linux-PAM</emphasis>.
          </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><type>int</type> <varname>pam_misc_conv_died</varname>;</term>
        <listitem>
          <para>
            Following a return from the <emphasis>Linux-PAM</emphasis>
            libraray, the value of this variable indicates whether the
            conversation has timed out. A value of
            <returnvalue>1</returnvalue> indicates the time-out occurred.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
    <para>
      The following two function pointers are available for supporting
      binary prompts in the conversation function. They are optimized
      for the current incarnation of the <command>libpamc</command>
      library and are subject to change.
    </para>
    <variablelist>
      <varlistentry>
        <term>
          <type>int</type> <varname>(*pam_binary_handler_fn)</varname>(<type>void *</type><varname>appdata</varname>, <type>pamc_bp_t *</type><varname>prompt_p</varname>);
        </term>
        <listitem>
          <para>
            This function pointer is initialized to
            <returnvalue>NULL</returnvalue> but can be filled with a
            function that provides machine-machine (hidden) message
            exchange. It is intended for use with hidden authentication
            protocols such as RSA or Diffie-Hellman key exchanges.
            (This is still under development.)
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>
          <type>int</type> <varname>(*pam_binary_handler_free)</varname>(<type>void *</type><varname>appdata</varname>, <type>pamc_bp_t *</type><varname>delete_me</varname>);
        </term>
        <listitem>
          <para>
            This function pointer is initialized to
            <function>PAM_BP_RENEW(delete_me, 0, 0)</function>, but can be
            redefined as desired by the application.
          </para>
        </listitem>
      </varlistentry>
     </variablelist>
  </refsect1>

  <refsect1 id='misc_conv-see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
        <refentrytitle>pam_conv</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>
    </para>
  </refsect1>

  <refsect1 id='misc_conv-standards'>
    <title>STANDARDS</title>
    <para>
      The <function>misc_conv</function> function is part of the
      <command>libpam_misc</command> Library and not defined in any
      standard.
    </para>
  </refsect1>

</refentry>
