CODEWITHSUNDEEP
phpapacheapache-config
justjoe
justjoe

Reputation: 5574

PHP : How to understand bitmask value of access from ini_get_all function

i'm start to use ini_get_all function to retrieve all configuration option on a shared host server. in the end i got this chunk of array :

[allow_call_time_pass_reference] => Array
    (
        [global_value] => 1
        [local_value] => 1
        [access] => 6
    )

[allow_url_fopen] => Array
    (
        [global_value] => 1
        [local_value] => 1
        [access] => 4
    )

The PHP manual just give descripstion :

It's possible for a directive to have multiple access levels, which is why access shows the appropriate bitmask values.

so, can anybody explain about 'access' ? ans how to understand its bitmask values ?

Upvotes: 3

Views: 823

Answers (2)

jor
jor

Reputation: 2157

Correct values

I looked it up in the PHP source code and found what you could define as your constants:

define('PHP_INI_USER', 1)
define('PHP_INI_PERDIR', 2)
define('PHP_INI_SYSTEM', 4)
define('PHP_INI_ALL', PHP_INI_USER | PHP_INI_PERDIR | PHP_INI_SYSTEM); // = 7

To check an access level from ini_get_all() you can do (using allow_url_fopen as an example):

$all = ini_get_all();
$config = $all['allow_url_fopen'];
$isUserLevel = $config['access'] & PHP_INI_USER; // PHP_INI_USER = 1

For reference

In the PHP's source code in main/php_ini.h these constants are defined as aliases of the Zend equivalents:

#define PHP_INI_USER    ZEND_INI_USER
#define PHP_INI_PERDIR  ZEND_INI_PERDIR
#define PHP_INI_SYSTEM  ZEND_INI_SYSTEM

#define PHP_INI_ALL ZEND_INI_ALL

https://github.com/php/php-src/blob/c8aa6f3a9a3d2c114d0c5e0c9fdd0a465dbb54a5/main/php_ini.h#L45 (lines 45 to 49)

The Zend equivalents are defined in Zend/zend_ini.h as follows:

#define ZEND_INI_USER   (1<<0)
#define ZEND_INI_PERDIR (1<<1)
#define ZEND_INI_SYSTEM (1<<2)

#define ZEND_INI_ALL (ZEND_INI_USER|ZEND_INI_PERDIR|ZEND_INI_SYSTEM)

https://github.com/php/php-src/blob/c8aa6f3a9a3d2c114d0c5e0c9fdd0a465dbb54a5/Zend/zend_ini.h#L24 (lines 24 to 28)

<< is the bitwise shift operator in C++ so 1<<0 = 1, 1<<1 = 2, 1<<2 = 4. ZEND_INI_ALL is the addition of 1+2+4 = 7.

Upvotes: 2

zneak
zneak

Reputation: 138171

Would you have read a little further in the "Return Value" section, you'd have found the link to the change modes and what they mean:

  • 1: PHP_INI_USER: Entry can be set in user scripts (like with ini_set()) or in the Windows registry
  • 2: PHP_INI_PERDIR: Entry can be set in php.ini, .htaccess or httpd.conf
  • 4: PHP_INI_SYSTEM: Entry can be set in php.ini or httpd.conf
  • 7: PHP_INI_ALL: Entry can be set anywhere

Upvotes: 9

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