<refentry xmlns="http://docbook.org/ns/docbook" version="5.0" xml:id="pam_chauthtok">
  <refmeta>
    <refentrytitle>pam_chauthtok</refentrytitle>
    <manvolnum>3</manvolnum>
    <refmiscinfo class="source">Linux-PAM</refmiscinfo>
    <refmiscinfo class="manual">Linux-PAM Manual</refmiscinfo>
  </refmeta>

  <refnamediv xml:id="pam_chauthtok-name">
    <refname>pam_chauthtok</refname>
    <refpurpose>updating authentication tokens</refpurpose>
  </refnamediv>

<!-- body begins here -->

  <refsynopsisdiv>
    <funcsynopsis xml:id="pam_chauthtok-synopsis">
      <funcsynopsisinfo>#include &lt;security/pam_appl.h&gt;</funcsynopsisinfo>
      <funcprototype>
        <funcdef>int <function>pam_chauthtok</function></funcdef>
        <paramdef>pam_handle_t *<parameter>pamh</parameter></paramdef>
        <paramdef>int <parameter>flags</parameter></paramdef>
      </funcprototype>
    </funcsynopsis>
  </refsynopsisdiv>


  <refsect1 xml:id="pam_chauthtok-description">
    <title>DESCRIPTION</title>
    <para>
      The <function>pam_chauthtok</function> function is used to change the
      authentication token for a given user (as indicated by the state
      associated with the handle <emphasis>pamh</emphasis>).
    </para>
    <para>
      The <emphasis>pamh</emphasis> argument is an authentication
      handle obtained by a prior call to pam_start().
      The flags argument is the binary or of zero or more of the
      following values:
    </para>
    <variablelist>
      <varlistentry>
        <term>PAM_SILENT</term>
        <listitem>
           <para>
             Do not emit any messages.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_CHANGE_EXPIRED_AUTHTOK</term>
        <listitem>
          <para>
            This argument indicates to the modules that the user's
            authentication token (password) should only be changed
            if it has expired.
            If this argument is not passed, the application requires
            that all authentication tokens are to be changed.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 xml:id="pam_chauthtok-return_values">
    <title>RETURN VALUES</title>
    <variablelist>
      <varlistentry>
        <term>PAM_AUTHTOK_ERR</term>
        <listitem>
           <para>
             A module was unable to obtain the new authentication token.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_AUTHTOK_RECOVERY_ERR</term>
        <listitem>
           <para>
             A module was unable to obtain the old authentication token.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_AUTHTOK_LOCK_BUSY</term>
        <listitem>
           <para>
             One or more of the modules was unable to change the
             authentication token since it is currently locked.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_AUTHTOK_DISABLE_AGING</term>
        <listitem>
           <para>
             Authentication token aging has been disabled for at least
             one of the modules.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_PERM_DENIED</term>
        <listitem>
           <para>
             Permission denied.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_SUCCESS</term>
        <listitem>
           <para>
             The authentication token was successfully updated.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_TRY_AGAIN</term>
        <listitem>
           <para>
             Not all of the modules were in a position to update the
             authentication token(s). In such a case none of the user's
             authentication tokens are updated.
          </para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term>PAM_USER_UNKNOWN</term>
        <listitem>
           <para>
             User unknown to password service.
          </para>
        </listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 xml:id="pam_chauthtok-see_also">
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
        <refentrytitle>pam_start</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>pam_authenticate</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>pam_setcred</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>pam_get_item</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>pam_strerror</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
        <refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum>
      </citerefentry>
    </para>
  </refsect1>
</refentry>