shadow/man/shadow.3.xml

<?xml version="1.0" encoding="UTF-8"?>
<!--
   Copyright (c) 1989 - 1993, Julianne Frances Haugh
   Copyright (c) 2007 - 2008, Nicolas François
   All rights reserved.
  
   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:
   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.
   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.
   3. The name of the copyright holders or contributors may not be used to
      endorse or promote products derived from this software without
      specific prior written permission.
  
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT
   HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-->
<refentry id='shadow.3'>
  <!--  $Id$ -->
  <refmeta>
    <refentrytitle>shadow</refentrytitle>
    <manvolnum>3</manvolnum>
    <refmiscinfo class="sectdesc">Library Calls</refmiscinfo>
  </refmeta>
  <refnamediv id='name'>
    <refname>shadow</refname>
    <refname>getspnam</refname>
    <refpurpose>encrypted password file routines</refpurpose>
  </refnamediv>

  <refsect1 id='syntax'>
    <title>SYNTAX</title>
    <para>
      <emphasis>#include &lt;shadow.h&gt;</emphasis>
    </para>

    <para>
      <emphasis>struct spwd *getspent();</emphasis>
    </para>

    <para>
      <emphasis>struct spwd *getspnam(char</emphasis> <emphasis
      remap='I'>*name</emphasis><emphasis>);</emphasis>
    </para>

    <para>
      <emphasis>void setspent();</emphasis>
    </para>

    <para>
      <emphasis>void endspent();</emphasis>
    </para>

    <para>
      <emphasis>struct spwd *fgetspent(FILE</emphasis> <emphasis
      remap='I'>*fp</emphasis><emphasis>);</emphasis>
    </para>

    <para>
      <emphasis>struct spwd *sgetspent(char</emphasis> <emphasis
      remap='I'>*cp</emphasis><emphasis>);</emphasis>
    </para>

    <para>
      <emphasis>int putspent(struct spwd</emphasis> <emphasis
      remap='I'>*p,</emphasis> <emphasis>FILE</emphasis> <emphasis
      remap='I'>*fp</emphasis><emphasis>);</emphasis>
    </para>

    <para>
      <emphasis>int lckpwdf();</emphasis>
    </para>

    <para>
      <emphasis>int ulckpwdf();</emphasis>
    </para>
  </refsect1>

  <refsect1 id='description'>
    <title>DESCRIPTION</title>
    <para>
      <emphasis remap='I'>shadow</emphasis> manipulates the contents of the
      shadow password file, <filename>/etc/shadow</filename>. The structure
      in the <emphasis remap='I'>#include</emphasis> file is:
    </para>
    <programlisting>struct spwd {
      char		*sp_namp; /* user login name */
      char		*sp_pwdp; /* encrypted password */
      long int		sp_lstchg; /* last password change */
      long int		sp_min; /* days until change allowed. */
      long int		sp_max; /* days before change required */
      long int		sp_warn; /* days warning for expiration */
      long int		sp_inact; /* days before account inactive */
      long int		sp_expire; /* date when account expires */
      unsigned long int	sp_flag; /* reserved for future use */
}
    </programlisting>
    <para>The meanings of each field are:</para>
    <itemizedlist mark='bullet'>
      <listitem>
	<para>sp_namp - pointer to null-terminated user name</para>
      </listitem>
      <listitem>
	<para>sp_pwdp - pointer to null-terminated password</para>
      </listitem>
      <listitem>
	<para>sp_lstchg - days since Jan 1, 1970 password was last changed</para>
      </listitem>
      <listitem>
	<para>sp_min - days before which password may not be changed</para>
      </listitem>
      <listitem>
	<para>sp_max - days after which password must be changed</para>
      </listitem>
      <listitem>
	 <para>sp_warn - days before password is to expire that user is warned of
	   pending password expiration
	 </para>
      </listitem>
      <listitem>
	<para>sp_inact - days after password expires that account is considered
	  inactive and disabled
	</para>
      </listitem>
      <listitem>
	<para>sp_expire - days since Jan 1, 1970 when account will be disabled</para>
      </listitem>
      <listitem>
	<para>sp_flag - reserved for future use</para>
      </listitem>
    </itemizedlist>

  </refsect1>

  <refsect1 id='description2'>
    <title>DESCRIPTION</title>
    <para>
      <emphasis>getspent</emphasis>, <emphasis>getspname</emphasis>,
      <emphasis>fgetspent</emphasis>, and <emphasis>sgetspent</emphasis>
      each return a pointer to a <emphasis>struct spwd</emphasis>.
      <emphasis>getspent</emphasis> returns the next entry from the file,
      and <emphasis>fgetspent</emphasis> returns the next entry from the
      given stream, which is assumed to be a file of the proper format.
      <emphasis>sgetspent</emphasis> returns a pointer to a <emphasis>struct
      spwd</emphasis> using the provided string as input.
      <emphasis>getspnam</emphasis> searches from the current position in
      the file for an entry matching <emphasis>name</emphasis>.
    </para>

    <para>
      <emphasis>setspent</emphasis> and <emphasis>endspent</emphasis> may be
      used to begin and end, respectively, access to the shadow password
      file.
    </para>
    
    <para>
      The <emphasis>lckpwdf</emphasis> and <emphasis>ulckpwdf</emphasis>
      routines should be used to insure exclusive access to the
      <filename>/etc/shadow</filename> file.  <emphasis>lckpwdf</emphasis>
      attempts to acquire a lock using <emphasis>pw_lock</emphasis> for up
      to 15 seconds. It continues by attempting to acquire a second lock
      using <emphasis>spw_lock</emphasis> for the remainder of the initial
      15 seconds. Should either attempt fail after a total of 15 seconds,
      <emphasis>lckpwdf</emphasis> returns -1. When both locks are acquired
      0 is returned.
    </para>
  </refsect1>

  <refsect1 id='diagnostics'>
    <title>DIAGNOSTICS</title>
    <para>
      Routines return NULL if no more entries are available or if an error
      occurs during processing. Routines which have <emphasis>int</emphasis>
      as the return value return 0 for success and
      -1 for failure.
    </para>
  </refsect1>

  <refsect1 id='caveats'>
    <title>CAVEATS</title>
    <para>
      These routines may only be used by the superuser as access to the
      shadow password file is restricted.
    </para>
  </refsect1>

  <refsect1 id='files'>
    <title>FILES</title>
    <variablelist>
      <varlistentry>
	<term><filename>/etc/shadow</filename></term>
	<listitem>
	  <para>Secure user account information.</para>
	</listitem>
      </varlistentry>
    </variablelist>
  </refsect1>

  <refsect1 id='see_also'>
    <title>SEE ALSO</title>
    <para>
      <citerefentry>
	<refentrytitle>getpwent</refentrytitle><manvolnum>3</manvolnum>
      </citerefentry>,
      <citerefentry>
	<refentrytitle>shadow</refentrytitle><manvolnum>5</manvolnum>
      </citerefentry>.
    </para>
  </refsect1>
</refentry>