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<title>User::pwent - by-name interface to Perl's built-in getpw* functions</title>
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<h1><a>User::pwent - by-name interface to Perl's built-in getpw* functions</a></h1>
<p><a name="__index__"></a></p>
<!-- INDEX BEGIN -->
<ul>
<li><a href="#name">NAME</a></li>
<li><a href="#synopsis">SYNOPSIS</a></li>
<li><a href="#description">DESCRIPTION</a></li>
<ul>
<li><a href="#system_specifics">System Specifics</a></li>
</ul>
<li><a href="#note">NOTE</a></li>
<li><a href="#author">AUTHOR</a></li>
<li><a href="#history">HISTORY</a></li>
</ul>
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<p>
</p>
<h1><a name="name">NAME</a></h1>
<p>User::pwent - by-name interface to Perl's built-in getpw*() functions</p>
<p>
</p>
<hr />
<h1><a name="synopsis">SYNOPSIS</a></h1>
<pre>
<span class="keyword">use</span> <span class="variable">User::pwent</span><span class="operator">;</span>
<span class="variable">$pw</span> <span class="operator">=</span> <span class="keyword">getpwnam</span><span class="operator">(</span><span class="string">'daemon'</span><span class="operator">)</span> <span class="operator">||</span> <span class="keyword">die</span> <span class="string">"No daemon user"</span><span class="operator">;</span>
<span class="keyword">if</span> <span class="operator">(</span> <span class="variable">$pw</span><span class="operator">-></span><span class="variable">uid</span> <span class="operator">==</span> <span class="number">1</span> <span class="operator">&&</span> <span class="variable">$pw</span><span class="operator">-></span><span class="variable">dir</span> <span class="operator">=~</span> <span class="regex">m#^/(bin|tmp)?\z#s</span> <span class="operator">)</span> <span class="operator">{</span>
<span class="keyword">print</span> <span class="string">"gid 1 on root dir"</span><span class="operator">;</span>
<span class="operator">}</span>
</pre>
<pre>
<span class="variable">$real_shell</span> <span class="operator">=</span> <span class="variable">$pw</span><span class="operator">-></span><span class="variable">shell</span> <span class="operator">||</span> <span class="string">'/bin/sh'</span><span class="operator">;</span>
</pre>
<pre>
<span class="keyword">for</span> <span class="operator">((</span><span class="variable">$fullname</span><span class="operator">,</span> <span class="variable">$office</span><span class="operator">,</span> <span class="variable">$workphone</span><span class="operator">,</span> <span class="variable">$homephone</span><span class="operator">)</span> <span class="operator">=</span>
<span class="keyword">split</span> <span class="regex">/\s*,\s*/</span><span class="operator">,</span> <span class="variable">$pw</span><span class="operator">-></span><span class="variable">gecos</span><span class="operator">)</span>
<span class="operator">{</span>
<span class="regex">s/&/ucfirst(lc($pw->name))/ge</span><span class="operator">;</span>
<span class="operator">}</span>
</pre>
<pre>
<span class="keyword">use</span> <span class="variable">User::pwent</span> <span class="string">qw(:FIELDS)</span><span class="operator">;</span>
<span class="keyword">getpwnam</span><span class="operator">(</span><span class="string">'daemon'</span><span class="operator">)</span> <span class="operator">||</span> <span class="keyword">die</span> <span class="string">"No daemon user"</span><span class="operator">;</span>
<span class="keyword">if</span> <span class="operator">(</span> <span class="variable">$pw_uid</span> <span class="operator">==</span> <span class="number">1</span> <span class="operator">&&</span> <span class="variable">$pw_dir</span> <span class="operator">=~</span> <span class="regex">m#^/(bin|tmp)?\z#s</span> <span class="operator">)</span> <span class="operator">{</span>
<span class="keyword">print</span> <span class="string">"gid 1 on root dir"</span><span class="operator">;</span>
<span class="operator">}</span>
</pre>
<pre>
<span class="variable">$pw</span> <span class="operator">=</span> <span class="variable">getpw</span><span class="operator">(</span><span class="variable">$whoever</span><span class="operator">);</span>
</pre>
<pre>
<span class="keyword">use</span> <span class="variable">User::pwent</span> <span class="string">qw/:DEFAULT pw_has/</span><span class="operator">;</span>
<span class="keyword">if</span> <span class="operator">(</span><span class="variable">pw_has</span><span class="operator">(</span><span class="string">qw[gecos expire quota]</span><span class="operator">))</span> <span class="operator">{</span> <span class="operator">....</span> <span class="operator">}</span>
<span class="keyword">if</span> <span class="operator">(</span><span class="variable">pw_has</span><span class="operator">(</span><span class="string">"name uid gid passwd"</span><span class="operator">))</span> <span class="operator">{</span> <span class="operator">....</span> <span class="operator">}</span>
<span class="keyword">print</span> <span class="string">"Your struct pwd has: "</span><span class="operator">,</span> <span class="keyword">scalar</span> <span class="variable">pw_has</span><span class="operator">(),</span> <span class="string">"\n"</span><span class="operator">;</span>
</pre>
<p>
</p>
<hr />
<h1><a name="description">DESCRIPTION</a></h1>
<p>This module's default exports override the core getpwent(), getpwuid(),
and <a href="../../lib/Pod/perlfunc.html#item_getpwnam"><code>getpwnam()</code></a> functions, replacing them with versions that return
<code>User::pwent</code> objects. This object has methods that return the
similarly named structure field name from the C's passwd structure
from <em>pwd.h</em>, stripped of their leading "pw_" parts, namely <code>name</code>,
<code>passwd</code>, <code>uid</code>, <code>gid</code>, <code>change</code>, <code>age</code>, <code>quota</code>, <code>comment</code>,
<code>class</code>, <code>gecos</code>, <code>dir</code>, <code>shell</code>, and <code>expire</code>. The <code>passwd</code>,
<code>gecos</code>, and <code>shell</code> fields are tainted when running in taint mode.</p>
<p>You may also import all the structure fields directly into your
namespace as regular variables using the :FIELDS import tag. (Note
that this still overrides your core functions.) Access these fields
as variables named with a preceding <code>pw_</code> in front their method
names. Thus, <code>$passwd_obj->shell</code> corresponds to $pw_shell
if you import the fields.</p>
<p>The <code>getpw()</code> function is a simple front-end that forwards
a numeric argument to <a href="../../lib/Pod/perlfunc.html#item_getpwuid"><code>getpwuid()</code></a> and the rest to getpwnam().</p>
<p>To access this functionality without the core overrides, pass the
<a href="../../lib/Pod/perlfunc.html#item_use"><code>use</code></a> an empty import list, and then access function functions
with their full qualified names. The built-ins are always still
available via the <code>CORE::</code> pseudo-package.</p>
<p>
</p>
<h2><a name="system_specifics">System Specifics</a></h2>
<p>Perl believes that no machine ever has more than one of <code>change</code>,
<code>age</code>, or <code>quota</code> implemented, nor more than one of either
<code>comment</code> or <code>class</code>. Some machines do not support <code>expire</code>,
<code>gecos</code>, or allegedly, <code>passwd</code>. You may call these methods
no matter what machine you're on, but they return <a href="../../lib/Pod/perlfunc.html#item_undef"><code>undef</code></a> if
unimplemented.</p>
<p>You may ask whether one of these was implemented on the system Perl
was built on by asking the importable <code>pw_has</code> function about them.
This function returns true if all parameters are supported fields
on the build platform, false if one or more were not, and raises
an exception if you asked about a field that Perl never knows how
to provide. Parameters may be in a space-separated string, or as
separate arguments. If you pass no parameters, the function returns
the list of <code>struct pwd</code> fields supported by your build platform's
C library, as a list in list context, or a space-separated string
in scalar context. Note that just because your C library had
a field doesn't necessarily mean that it's fully implemented on
that system.</p>
<p>Interpretation of the <code>gecos</code> field varies between systems, but
traditionally holds 4 comma-separated fields containing the user's
full name, office location, work phone number, and home phone number.
An <code>&</code> in the gecos field should be replaced by the user's properly
capitalized login <code>name</code>. The <code>shell</code> field, if blank, must be
assumed to be <em>/bin/sh</em>. Perl does not do this for you. The
<code>passwd</code> is one-way hashed garble, not clear text, and may not be
unhashed save by brute-force guessing. Secure systems use more a
more secure hashing than DES. On systems supporting shadow password
systems, Perl automatically returns the shadow password entry when
called by a suitably empowered user, even if your underlying
vendor-provided C library was too short-sighted to realize it should
do this.</p>
<p>See <code>passwd(5)</code> and <a href="../../lib/Pod/perlfunc.html#item_getpwent"><code>getpwent(3)</code></a> for details.</p>
<p>
</p>
<hr />
<h1><a name="note">NOTE</a></h1>
<p>While this class is currently implemented using the Class::Struct
module to build a struct-like class, you shouldn't rely upon this.</p>
<p>
</p>
<hr />
<h1><a name="author">AUTHOR</a></h1>
<p>Tom Christiansen</p>
<p>
</p>
<hr />
<h1><a name="history">HISTORY</a></h1>
<dl>
<dt><strong><a name="item_march_18th_2c_2000">March 18th, 2000</a></strong>
<dd>
<p>Reworked internals to support better interface to dodgey fields
than normal Perl function provides. Added <code>pw_has()</code> field. Improved
documentation.</p>
</dd>
</li>
</dl>
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