Edit File: adg-libpam-functions.html
<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 V1.78.1"><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 <security/pam_misc.h></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 <security/pam_misc.h></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 <security/pam_misc.h></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 <security/pam_misc.h></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>