to get the username of the process owner (rather than the file owner), you can use:
<?php
$processUser = posix_getpwuid(posix_geteuid());
print $processUser['name'];
?>
(PHP 4, PHP 5, PHP 7)
get_current_user — Gets the name of the owner of the current PHP script
Returns the name of the owner of the current PHP script.
Returns the username as a string.
Example #1 get_current_user() example
<?php
echo 'Current script owner: ' . get_current_user();
?>
The above example will output something similar to:
Current script owner: SYSTEM
to get the username of the process owner (rather than the file owner), you can use:
<?php
$processUser = posix_getpwuid(posix_geteuid());
print $processUser['name'];
?>
On Centos, the Red Hat linux clone, this instruction gives the file's OWNER (the first parameter in instruction 'chown'). It does not reveal the file's GROUP.
get_current_user() does NOT reveal the current process' user's identity.
See: posix_getuid() - Return the real user ID of the current process
The information returned by get_current_user() seems to depend on the platform.
Using PHP 5.1.1 running as CGI with IIS 5.0 on Windows NT, get_current_user() returns the owner of the process running the script, *not* the owner of the script itself.
It's easy to test - create a file containing:
<?php
echo get_current_user();
?>
Then access it through the browser. I get: IUSR_MACHINE, the Internet Guest Account on Windows, which is certainly not the owner of the script.
If you want to get the name of the user who executes the current PHP script, you can use
<?php
$username = getenv('USERNAME') ?: getenv('USER');
echo $username; // e.g. root or www-data
?>
Since this only returns the file owner and not the actual user running the script, an alternative in Linux is:
<?php
$current_user = trim(shell_exec('whoami'));
?>