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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>5.1. Functions supplied</title><meta name="generator" content="DocBook XSL Stylesheets Vsnapshot"><link rel="home" href="Linux-PAM_ADG.html" title="The Linux-PAM Application Developers' Guide"><link rel="up" href="adg-libpam_misc.html" title="Chapter 5. A library of miscellaneous helper functions"><link rel="prev" href="adg-libpam_misc.html" title="Chapter 5. A library of miscellaneous helper functions"><link rel="next" href="adg-porting.html" title="Chapter 6. Porting legacy applications"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">5.1. Functions supplied</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="adg-libpam_misc.html">Prev</a> </td><th width="60%" align="center">Chapter 5. A library of miscellaneous helper functions</th><td width="20%" align="right"> <a accesskey="n" href="adg-porting.html">Next</a></td></tr></table><hr></div><div class="section"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a name="adg-libpam-functions"></a>5.1. Functions supplied</h2></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="adg-misc_conv"></a>5.1.1. Text based conversation function</h3></div></div></div><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;security/pam_misc.h&gt;</pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">misc_conv</b>(</code></td><td><var class="pdparam">num_msg</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">msgm</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">response</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">appdata_ptr</var><code>)</code>;</td><td> </td></tr></table><div class="paramdef-list"><code>int <var class="pdparam">num_msg</var></code>;<br><code>const struct pam_message **<var class="pdparam">msgm</var></code>;<br><code>struct pam_response **<var class="pdparam">response</var></code>;<br><code>void *<var class="pdparam">appdata_ptr</var></code>;</div><div class="funcprototype-spacer"> </div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="adg-misc_conv-description"></a>5.1.1.1. DESCRIPTION</h4></div></div></div><p>
      The <code class="function">misc_conv</code> function is part of
      <span class="command"><strong>libpam_misc</strong></span> and not of the standard
      <span class="command"><strong>libpam</strong></span> library. This function will prompt
      the user with the appropriate comments and obtain the appropriate
      inputs as directed by authentication modules.
    </p><p>
      In addition to simply slotting into the appropriate <span class="citerefentry"><span class="refentrytitle">pam_conv</span>(3)</span>, 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:
    </p><div class="variablelist"><dl class="variablelist"><dt><span class="term"><span class="type">time_t</span> <code class="varname">pam_misc_conv_warn_time</code>;</span></dt><dd><p>
            This variable contains the <span class="emphasis"><em>time</em></span> (as
            returned by <span class="citerefentry"><span class="refentrytitle">time</span>(2)</span>) that the user should be first warned that
            the clock is ticking. By default it has the value
            <span class="returnvalue">0</span>, 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 <span class="emphasis"><em>Linux-PAM</em></span> library.
          </p></dd><dt><span class="term"><span class="type">const char *</span><code class="varname">pam_misc_conv_warn_line</code>;</span></dt><dd><p>
            Used in conjuction with
            <code class="varname">pam_misc_conv_warn_time</code>, 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
            <span class="quote">“<span class="quote">...Time is running out...</span>”</span>, but this can be
            changed by the application prior to passing control to
            <span class="emphasis"><em>Linux-PAM</em></span>.
          </p></dd><dt><span class="term"><span class="type">time_t</span> <code class="varname">pam_misc_conv_die_time</code>;</span></dt><dd><p>
            This variable contains the <span class="emphasis"><em>time</em></span> (as
            returned by <span class="citerefentry"><span class="refentrytitle">time</span>(2)</span>) that the will time out. By default it has
            the value <span class="returnvalue">0</span>, 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
            <span class="emphasis"><em>Linux-PAM</em></span> library.
          </p></dd><dt><span class="term"><span class="type">const char *</span><code class="varname">pam_misc_conv_die_line</code>;</span></dt><dd><p>
            Used in conjuction with
            <code class="varname">pam_misc_conv_die_time</code>, 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
            <span class="quote">“<span class="quote">...Sorry, your time is up!</span>”</span>, but this can be
            changed by the application prior to passing control to
            <span class="emphasis"><em>Linux-PAM</em></span>.
          </p></dd><dt><span class="term"><span class="type">int</span> <code class="varname">pam_misc_conv_died</code>;</span></dt><dd><p>
            Following a return from the <span class="emphasis"><em>Linux-PAM</em></span>
            libraray, the value of this variable indicates whether the
            conversation has timed out. A value of
            <span class="returnvalue">1</span> indicates the time-out occurred.
          </p></dd></dl></div><p>
      The following two function pointers are available for supporting
      binary prompts in the conversation function. They are optimized
      for the current incarnation of the <span class="command"><strong>libpamc</strong></span>
      library and are subject to change.
    </p><div class="variablelist"><dl class="variablelist"><dt><span class="term">
          <span class="type">int</span> <code class="varname">(*pam_binary_handler_fn)</code>(<span class="type">void *</span><code class="varname">appdata</code>, <span class="type">pamc_bp_t *</span><code class="varname">prompt_p</code>);
        </span></dt><dd><p>
            This function pointer is initialized to
            <span class="returnvalue">NULL</span> 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.)
          </p></dd><dt><span class="term">
          <span class="type">int</span> <code class="varname">(*pam_binary_handler_free)</code>(<span class="type">void *</span><code class="varname">appdata</code>, <span class="type">pamc_bp_t *</span><code class="varname">delete_me</code>);
        </span></dt><dd><p>
            This function pointer is initialized to
            <code class="function">PAM_BP_RENEW(delete_me, 0, 0)</code>, but can be
            redefined as desired by the application.
          </p></dd></dl></div></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="adg-pam_misc_paste_env"></a>5.1.2. Transcribing an environment to that of PAM</h3></div></div></div><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;security/pam_misc.h&gt;</pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">pam_misc_paste_env</b>(</code></td><td><var class="pdparam">pamh</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">user</var><code>)</code>;</td><td> </td></tr></table><div class="paramdef-list"><code>pam_handle_t *<var class="pdparam">pamh</var></code>;<br><code>const char * const *<var class="pdparam">user</var></code>;</div><div class="funcprototype-spacer"> </div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="adg-pam_misc_paste_env-description"></a>5.1.2.1. DESCRIPTION</h4></div></div></div><p>
      This function takes the supplied list of environment pointers and
      <span class="emphasis"><em>uploads</em></span> its contents to the PAM environment.
      Success is indicated by <span class="errorname">PAM_SUCCESS</span>.
    </p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="adg-pam_misc_drop_env"></a>5.1.3. Liberating a locally saved environment</h3></div></div></div><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;security/pam_misc.h&gt;</pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">pam_misc_drop_env</b>(</code></td><td><var class="pdparam">env</var><code>)</code>;</td><td> </td></tr></table><div class="paramdef-list"><code>char **<var class="pdparam">env</var></code>;</div><div class="funcprototype-spacer"> </div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="adg-pam_misc_drop_env-description"></a>5.1.3.1. DESCRIPTION</h4></div></div></div><p>
      This function is defined to complement the <span class="citerefentry"><span class="refentrytitle">pam_getenvlist</span>(3)</span> function. It liberates the memory associated
      with <em class="parameter"><code>env</code></em>, <span class="emphasis"><em>overwriting</em></span>
      with <span class="emphasis"><em>0</em></span> all memory before
      <code class="function">free()</code>ing it.
    </p></div></div><div class="section"><div class="titlepage"><div><div><h3 class="title"><a name="adg-pam_misc_setenv"></a>5.1.4. BSD like PAM environment variable setting</h3></div></div></div><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;security/pam_misc.h&gt;</pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">pam_misc_setenv</b>(</code></td><td><var class="pdparam">pamh</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">name</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">value</var>, </td><td> </td></tr><tr><td> </td><td><var class="pdparam">readonly</var><code>)</code>;</td><td> </td></tr></table><div class="paramdef-list"><code>pam_handle_t *<var class="pdparam">pamh</var></code>;<br><code>const char *<var class="pdparam">name</var></code>;<br><code>const char *<var class="pdparam">value</var></code>;<br><code>int <var class="pdparam">readonly</var></code>;</div><div class="funcprototype-spacer"> </div></div><div class="section"><div class="titlepage"><div><div><h4 class="title"><a name="adg-pam_misc_setenv-description"></a>5.1.4.1. DESCRIPTION</h4></div></div></div><p>
      This function performs a task equivalent to <span class="citerefentry"><span class="refentrytitle">pam_putenv</span>(3)</span>, its syntax is, however, more like the BSD style
      function; <code class="function">setenv()</code>. The <em class="parameter"><code>name</code></em>
      and <em class="parameter"><code>value</code></em> are concatenated with an '=' to
      form a name=value and passed to <code class="function">pam_putenv()</code>.
      If, however, the PAM variable is already set, the replacement will
      only be applied if the last argument, <em class="parameter"><code>readonly</code></em>,
      is zero.
    </p></div></div></div><div class="navfooter"><hr><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="adg-libpam_misc.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="adg-libpam_misc.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="adg-porting.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">Chapter 5. A library of miscellaneous helper functions </td><td width="20%" align="center"><a accesskey="h" href="Linux-PAM_ADG.html">Home</a></td><td width="40%" align="right" valign="top"> Chapter 6. Porting legacy applications</td></tr></table></div></body></html>