有没有办法看到哪些php.ini值具有非默认设置？

Question

I've had to do some archeology on an old PHP 5 server. I've been digging around in the ini files and it occurred to me that it would be very convenient to check which settings have non-default values. I've discovered php --ini and php -r 'php_info();' and other variants, as well as the ini_get_all() function, which can show the value set in the php ini files and any overridden value (e.g. from .htaccess or ini_set).

The php.net documentation describes a default setting for every ini directive. Is there a way to access these defaults from inside PHP code? That way I could do some simple array manipulations on the return value of ini_get_all and pick out which ones have non-default values.

I was looking at ini_restore and the example given reads as though it only restores to the startup value, i.e. the value configured in the ini files, not the php default value.

Answer 1

Additionally, you could rename your current ini file to something other than php.ini and restart PHP so that ini_get_all will give you the values which are baked into the core and use parse_ini_file() on your renamed file. – MonkeyZeus

This worked a charm! Before starting, I had a linked conf.d and I had overridden the cli/php.ini file to point to the apache2/php.ini file so that my php cli invocations would use the web server configs. The cli/php.ini file had been renamed .old, like so:

$ ls -l /etc/php5/cli/
total 68
lrwxrwxrwx 1 root root     9 Apr 24  2013 conf.d -> ../conf.d
lrwxrwxrwx 1 root root    25 Mar 13 05:04 php.ini -> /etc/php5/apache2/php.ini
-rw-r--r-- 1 root root 67629 Mar  4  2013 php.ini.old

I took the web server out of our load balancer pool and made some modifications.

$ rm /etc/php5/cli/conf.d /etc/php5/cli/php.ini
$ php --ini
Configuration File (php.ini) Path: /etc/php5/cli
Loaded Configuration File:         (none)
Scan for additional .ini files in: /etc/php5/cli/conf.d
Additional .ini files parsed:      (none)

I then added a file called check_config.php with these contents:

echo("
Defaults that are changed by or not present in ini file $path:
");
print_r(array_diff_assoc($defaults, $ini));

echo("
Values set by $path which differ from or are not included in the defaults:
");
print_r(array_diff_assoc($ini, $defaults));

And got some delicious output.

$ /usr/bin/php /etc/php5/cli/check_config.php 

Defaults that are changed by or not present in ini file /etc/php5/apache2/php.ini:
Array
(
    [allow_call_time_pass_reference] => 1
    [allow_url_include] => 0
    //...snip
)

Values set by /etc/php5/apache2/php.ini which differ from or are not included in the defaults:
Array
(
    [engine] => 1
    [asp_tags] => 
    //...snip
)

This did what I wanted, but it has a lot of red herrings - a lot of directives have a default value but are not included in the ini file and similarly a lot of module specific directives that are not in the values returned by ini_get_all(). I suppose I could improve this a bit by further finagling the config setups to enable more modules which should get their directives included in the list, but there are rather a lot of modules, so I think I'm good for now.