use XML::Simple

suppose I have a .passwds.xml file like this:

<?xml version="1.0"?>
<users>
 <user>
  <uid>0</uid>
  <name>root</name>
  <passwd>123456</passwd>
  <identity>root</identity>
 </user>
 <user>
  <uid>1</uid>
  <name>test</name>
  <passwd>123456</passwd>
  <identity>root</identity>
 </user>
</users>

and I can use the following perl script to parse it and determin whether a user can login

#!/usr/bin/perl
use XML::Simple;

$passwds = ".passwds.xml";

my $xmlobj = new XML::Simple(KeyAttr=>[]);

my $data = $xmlobj->XMLin("$passwds");

my $loggedin = -1;

my $username = "test";

my $password = "123456";

foreach  (@{$data->{"user"}}){
 if (($_->{"name"} ne $username)){
  next;
 }
 $loggedin = 0;
 if ($_->{"passwd"} eq $password){
  $loggedin = 1;
 }
 last;
}
if ($loggedin == -1){
 print "username incorrect\n";
 die;
}
if ($loggedin == 0){
 print "password incorrect";
 die;
}
print "successfully login\n";