granicus.if.org Git - linux-pam/blob - doc/man/pam_start.3.xml

   1 <?xml version="1.0" encoding="ISO-8859-1"?>
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
   3                    "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd">
   4
   5 <refentry id='pam_start'>
   6
   7   <refmeta>
   8     <refentrytitle>pam_start</refentrytitle>
   9     <manvolnum>3</manvolnum>
  10     <refmiscinfo class='setdesc'>Linux-PAM Manual</refmiscinfo>
  11   </refmeta>
  12
  13   <refnamediv id="pam_start-name">
  14     <refname>pam_start</refname>
  15     <refpurpose>initialization of PAM transaction</refpurpose>
  16   </refnamediv>
  17
  18 <!-- body begins here -->
  19
  20   <refsynopsisdiv id="pam_start-synopsis">
  21     <funcsynopsis>
  22       <funcsynopsisinfo>#include &lt;security/pam_appl.h&gt;</funcsynopsisinfo>
  23       <funcprototype>
  24         <funcdef>int <function>pam_start</function></funcdef>
  25         <paramdef>const char *<parameter>service_name</parameter></paramdef>
  26         <paramdef>const char *<parameter>user</parameter></paramdef>
  27         <paramdef>const struct pam_conv *<parameter>pam_conversation</parameter></paramdef>
  28         <paramdef>pam_handle_t **<parameter>pamh</parameter></paramdef>
  29       </funcprototype>
  30     </funcsynopsis>
  31   </refsynopsisdiv>
  32
  33
  34   <refsect1 id="pam_start-description">
  35     <title>DESCRIPTION</title>
  36     <para>
  37       The <function>pam_start</function> function creates the PAM context
  38       and initiates the PAM transaction. It is the first of the PAM
  39       functions that needs to be called by an application.
  40     </para>
  41
  42     <para>
  43       The <emphasis>service_name</emphasis> argument specifies the name
  44       of the service to apply and will be stored as PAM_SERVICE item in
  45       the new context. The policy for the service will be read from the
  46       file <filename>/etc/pam.d/service_name</filename> or, if that file
  47       does not exist, from <filename>/etc/pam.conf</filename>.
  48     </para>
  49
  50     <para>
  51        The <emphasis>user</emphasis> argument can specify the name
  52        of the target user and will be stored as PAM_USER item. If
  53        the argument is NULL, the module has to ask for this item if
  54        necessary.
  55     </para>
  56
  57     <para>
  58        The <emphasis>pam_conversation</emphasis> argument points to
  59        a <emphasis>struct pam_conv</emphasis> describing the
  60        conversation function to use. An application must provide this
  61        for direct communication between a loaded module and the
  62        application.
  63     </para>
  64
  65     <para>
  66        Following a successful return (PAM_SUCCESS) the contents of
  67        <emphasis>pamh</emphasis> is a handle that contains the PAM
  68        context for successive calls to the PAM functions. In an error
  69        case is the content of <emphasis>pamh</emphasis> undefined.
  70     </para>
  71
  72     <para>
  73       The <emphasis>pam_handle_t</emphasis> is a blind structure and
  74       the application should not attempt to probe it directly for
  75       information. Instead the PAM library provides the functions
  76       <citerefentry>
  77         <refentrytitle>pam_set_item</refentrytitle><manvolnum>3</manvolnum>
  78       </citerefentry> and
  79       <citerefentry>
  80         <refentrytitle>pam_get_item</refentrytitle><manvolnum>3</manvolnum>
  81       </citerefentry>.
  82       The PAM handle cannot be used for mulitiple authentications at the
  83       same time as long as <function>pam_end</function> was not called on
  84       it before.
  85     </para>
  86   </refsect1>
  87   <refsect1 id="pam_start-return_values">
  88     <title>RETURN VALUES</title>
  89     <variablelist>
  90       <varlistentry>
  91         <term>PAM_ABORT</term>
  92         <listitem>
  93            <para>
  94               General failure.
  95           </para>
  96         </listitem>
  97       </varlistentry>
  98       <varlistentry>
  99         <term>PAM_BUF_ERR</term>
 100         <listitem>
 101            <para>
 102               Memory buffer error.
 103           </para>
 104         </listitem>
 105       </varlistentry>
 106       <varlistentry>
 107         <term>PAM_SUCCESS</term>
 108         <listitem>
 109            <para>
 110              Transaction was successful created.
 111           </para>
 112         </listitem>
 113       </varlistentry>
 114       <varlistentry>
 115         <term>PAM_SYSTEM_ERR</term>
 116         <listitem>
 117            <para>
 118               System error, for example a NULL pointer was submitted
 119               instead of a pointer to data.
 120           </para>
 121         </listitem>
 122       </varlistentry>
 123     </variablelist>
 124   </refsect1>
 125
 126   <refsect1 id="pam_start-see_also">
 127     <title>SEE ALSO</title>
 128     <para>
 129       <citerefentry>
 130         <refentrytitle>pam_get_data</refentrytitle><manvolnum>3</manvolnum>
 131       </citerefentry>,
 132       <citerefentry>
 133         <refentrytitle>pam_set_data</refentrytitle><manvolnum>3</manvolnum>
 134       </citerefentry>,
 135       <citerefentry>
 136         <refentrytitle>pam_end</refentrytitle><manvolnum>3</manvolnum>
 137       </citerefentry>,
 138       <citerefentry>
 139         <refentrytitle>pam_strerror</refentrytitle><manvolnum>3</manvolnum>
 140       </citerefentry>
 141     </para>
 142   </refsect1>
 143 </refentry>