同一页面中的两个php函数发生冲突，我可以更改为什么

我试图通过使成员专用区域成为保护页面的区域，在这种情况下我使用的代码是

<?php 
include 'dbc.php';
page_protect();

?>

使用此代码没有错误，而且工作正常但问题是，每当我把下面的代码放在同一页上时问题会发生在iPhone上，只有这个设备，但其他设备仍然可以，比如PC、笔记本电脑和平板电脑（iPad），它们都没有问题

但iPhone的问题是，你可以在登录后访问该页面，但无论何时刷新，它都会将你重定向到登录页面，并要求再次登录。

<?php
if(!isset($_GET['link'])){ 
    $link = 1; 
} else { 
    $link = $_GET['link']; 
}
if ($link == 1) {
echo "";
} elseif ($link == 23) {
echo "";
} else {
echo "";
} 
?>

没有错误显示或任何内容。

我的问题是，无论如何都有保护页面的功能，因为我需要这是会员专用区域，上面的代码非常重要，需要在页面中。

提前谢谢。

这是dbc.php对此感到抱歉，但我复制了整个脚本并将放在这里

<?php
/*************** PHP LOGIN SCRIPT V 2.3*********************
(c) Balakrishnan 2010. All Rights Reserved
Usage: This script can be used FREE of charge for any commercial or personal projects. Enjoy!
Limitations:
- This script cannot be sold.
- This script should have copyright notice intact. Dont remove it please...
- This script may not be provided for download except from its original site.
For further usage, please contact me.
/******************** MAIN SETTINGS - PHP LOGIN SCRIPT V2.1 **********************
Please complete wherever marked xxxxxxxxx
/************* MYSQL DATABASE SETTINGS *****************
1. Specify Database name in $dbname
2. MySQL host (localhost or remotehost)
3. MySQL user name with ALL previleges assigned.
4. MySQL password
Note: If you use cpanel, the name will be like account_database
*************************************************************/
define ("DB_HOST", "xxxxxx"); // set database host
define ("DB_USER", "xxxxxx"); // set database user
define ("DB_PASS","xxxxxxx"); // set database password
define ("DB_NAME","xxxxxx"); // set database name
$link = mysql_connect(DB_HOST, DB_USER, DB_PASS) or die("Couldn't make connection.");
$db = mysql_select_db(DB_NAME, $link) or die("Couldn't select database");
/* Registration Type (Automatic or Manual) 
 1 -> Automatic Registration (Users will receive activation code and they will be automatically approved after clicking activation link)
 0 -> Manual Approval (Users will not receive activation code and you will need to approve every user manually)
*/
$user_registration = 1;  // set 0 or 1
define("COOKIE_TIME_OUT", 10); //specify cookie timeout in days (default is 10 days)
define('SALT_LENGTH', 9); // salt for password
//define ("ADMIN_NAME", "admin"); // sp
/* Specify user levels */
define ("ADMIN_LEVEL", 5);
define ("USER_LEVEL", 1);
define ("GUEST_LEVEL", 0);

/*************** reCAPTCHA KEYS****************/
$publickey = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";
$privatekey = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx";

/**** PAGE PROTECT CODE  ********************************
This code protects pages to only logged in users. If users have not logged in then it will redirect to login page.
If you want to add a new page and want to login protect, COPY this from this to END marker.
Remember this code must be placed on very top of any html or php page.
********************************************************/
function page_protect() {
session_start();
global $db; 
/* Secure against Session Hijacking by checking user agent */
if (isset($_SESSION['HTTP_USER_AGENT']))
{
    if ($_SESSION['HTTP_USER_AGENT'] != md5($_SERVER['HTTP_USER_AGENT']))
    {
        logout();
        exit;
    }
}
// before we allow sessions, we need to check authentication key - ckey and ctime stored in database
/* If session not set, check for cookies set by Remember me */
if (!isset($_SESSION['user_id']) && !isset($_SESSION['user_name']) ) 
{
    if(isset($_COOKIE['user_id']) && isset($_COOKIE['user_key'])){
    /* we double check cookie expiry time against stored in database */
    $cookie_user_id  = filter($_COOKIE['user_id']);
    $rs_ctime = mysql_query("select `ckey`,`ctime` from `users` where `id` ='$cookie_user_id'") or die(mysql_error());
    list($ckey,$ctime) = mysql_fetch_row($rs_ctime);
    // coookie expiry
    if( (time() - $ctime) > 60*60*24*COOKIE_TIME_OUT) {
        logout();
        }
/* Security check with untrusted cookies - dont trust value stored in cookie.       
/* We also do authentication check of the `ckey` stored in cookie matches that stored in database during login*/
     if( !empty($ckey) && is_numeric($_COOKIE['user_id']) && isUserID($_COOKIE['user_name']) && $_COOKIE['user_key'] == sha1($ckey)  ) {
          session_regenerate_id(); //against session fixation attacks.
          $_SESSION['user_id'] = $_COOKIE['user_id'];
          $_SESSION['user_name'] = $_COOKIE['user_name'];
        /* query user level from database instead of storing in cookies */  
          list($user_level) = mysql_fetch_row(mysql_query("select user_level from users where id='$_SESSION[user_id]'"));
          $_SESSION['user_level'] = $user_level;
          $_SESSION['HTTP_USER_AGENT'] = md5($_SERVER['HTTP_USER_AGENT']);
       } else {
       logout();
       }
  } else {
    header("Location: login.php");
    exit();
    }
}
}

function filter($data) {
    $data = trim(htmlentities(strip_tags($data)));
    if (get_magic_quotes_gpc())
        $data = stripslashes($data);
    $data = mysql_real_escape_string($data);
    return $data;
}

function EncodeURL($url)
{
$new = strtolower(ereg_replace(' ','_',$url));
return($new);
}
function DecodeURL($url)
{
$new = ucwords(ereg_replace('_',' ',$url));
return($new);
}
function ChopStr($str, $len) 
{
    if (strlen($str) < $len)
        return $str;
    $str = substr($str,0,$len);
    if ($spc_pos = strrpos($str," "))
            $str = substr($str,0,$spc_pos);
    return $str . "...";
}   
function isEmail($email){
  return preg_match('/^'S+@['w'd.-]{2,}'.['w]{2,6}$/iU', $email) ? TRUE : FALSE;
}
function isUserID($username)
{
    if (preg_match('/^[a-z'd_]{5,20}$/i', $username)) {
        return true;
    } else {
        return false;
    }
 }  
function isURL($url) 
{
    if (preg_match('/^(http|https|ftp):'/'/([A-Z0-9][A-Z0-9_-]*(?:'.[A-Z0-9][A-Z0-9_-]*)+):?('d+)?'/?/i', $url)) {
        return true;
    } else {
        return false;
    }
} 
function checkPwd($x,$y) 
{
if(empty($x) || empty($y) ) { return false; }
if (strlen($x) < 4 || strlen($y) < 4) { return false; }
if (strcmp($x,$y) != 0) {
 return false;
 } 
return true;
}
function GenPwd($length = 7)
{
  $password = "";
  $possible = "0123456789bcdfghjkmnpqrstvwxyz"; //no vowels
  $i = 0; 
  while ($i < $length) { 

    $char = substr($possible, mt_rand(0, strlen($possible)-1), 1);

    if (!strstr($password, $char)) { 
      $password .= $char;
      $i++;
    }
  }
  return $password;
}
function GenKey($length = 7)
{
  $password = "";
  $possible = "0123456789abcdefghijkmnopqrstuvwxyz"; 
  $i = 0; 
  while ($i < $length) { 

    $char = substr($possible, mt_rand(0, strlen($possible)-1), 1);

    if (!strstr($password, $char)) { 
      $password .= $char;
      $i++;
    }
  }
  return $password;
}

function logout()
{
global $db;
session_start();
if(isset($_SESSION['user_id']) || isset($_COOKIE['user_id'])) {
mysql_query("update `users` 
            set `ckey`= '', `ctime`= '' 
            where `id`='$_SESSION[user_id]' OR  `id` = '$_COOKIE[user_id]'") or die(mysql_error());
}           
/************ Delete the sessions****************/
unset($_SESSION['user_id']);
unset($_SESSION['user_name']);
unset($_SESSION['user_level']);
unset($_SESSION['HTTP_USER_AGENT']);
session_unset();
session_destroy(); 
/* Delete the cookies*******************/
setcookie("user_id", '', time()-60*60*24*COOKIE_TIME_OUT, "/");
setcookie("user_name", '', time()-60*60*24*COOKIE_TIME_OUT, "/");
setcookie("user_key", '', time()-60*60*24*COOKIE_TIME_OUT, "/");
header("Location: login.php");
}
// Password and salt generation
function PwdHash($pwd, $salt = null)
{
    if ($salt === null)     {
        $salt = substr(md5(uniqid(rand(), true)), 0, SALT_LENGTH);
    }
    else     {
        $salt = substr($salt, 0, SALT_LENGTH);
    }
    return $salt . sha1($pwd . $salt);
}
function checkAdmin() {
if($_SESSION['user_level'] == ADMIN_LEVEL) {
return 1;
} else { return 0 ;
}
}
?>