[php] How to check what user php is running as?

I need to detect if php is running as nobody. How do I do this?

Are there any other names for "nobody"? "apache"? Any others?

$_SERVER["USER"]

$_SERVER["USERNAME"] 

$user = $_SERVER['REMOTE_USER'];

http://php.net/manual/en/reserved.variables.server.php

Authenticated user

More details would be useful, but assuming it's a linux system, and assuming php is running under apache, it will run as what ever user apache runs as.

An easy way to check ( again, assuming some unix like environment ) is to create a php file with:

<?php
    print shell_exec( 'whoami' );
?>

which will give you the user.

For my AWS instance, I am getting apache as output when I run this script.

Proposal

A tad late, but even though the following is a work-around, it solves the requirement as this works just fine:

<?
    function get_sys_usr()
    {
        $unique_name = uniqid();  // not-so-unique id
        $native_path = "./temp/$unique_name.php";
        $public_path = "http://example.com/temp/$unique_name.php";
        $php_content = "<? echo get_current_user(); ?>";
        $process_usr = "apache";  // fall-back

        if (is_readable("./temp") && is_writable("./temp"))
        {
            file_put_contents($native_path,$php_content);
            $process_usr = trim(file_get_contents($public_path));
            unlink($native_path);
        }

        return $process_usr;
    }


    echo get_sys_usr();  // www-data
?>

Description

The code-highlighting above is not accurate, please copy & paste in your favorite editor and view as PHP code, or save and test it yourself.

As you probably know, get_current_user() returns the owner of the "current running script" - so if you did not "chown" a script on the server to the web-server-user it will most probably be "nobody", or if the developer-user exists on the same OS, it will rather display that username.

To work around this, we create a file with the current running process. If you just require() this into the current running script, it will return the same as the parent-script as mentioned; so, we need to run it as a separate request to take effect.

Process-flow

In order to make this effective, consider running a design pattern that incorporates "runtime-mode", so when the server is in "development-mode or test-mode" then only it could run this function and save its output somewhere in an include, -or just plain text or database, or whichever.

Of course you can change some particulars of the code above as you wish to make it more dynamic, but the logic is as follows:

• define a unique reference to limit interference with other users
• define a local file-path for writing a temporary file
• define a public url/path to run this file in its own process
• write the temporary php file that outputs the script owner name
• get the output of this script by making a request to it
• delete the file as it is no longer needed - or leave it if you want
• return the output of the request as return-value of the function

i would use:

lsof -i
lsof -i | less
lsof -i | grep :http

any of these. You can type em in your ssh command line and you will see what user is listening what service.

you can also go and check this file:

more /etc/apache2/envvars

and look for these lines:

export APACHE_RUN_USER=user-name
export APACHE_RUN_GROUP=group-name

to filter out envvars file data, you can use grep:

 more  /etc/apache2/envvars |grep APACHE_RUN_

You can use these commands :

<? system('whoami');?>

or

<? passthru('whoami');?>

or

<? print exec('whoami');?>

or

<? print shell_exec('whoami');?>

Be aware, the get_current_user() returns the name of the owner of the current PHP script !

add the file info.php to the following directory - your default http/apache directory - normally /var/www/html

with the following contents

<?php                                                                           
phpinfo();                                                                    
?>  

Then httpd/apache restart the go to your default html directory http://enter.server.here/info.php

would deliver the whole php pedigree!

<?php echo exec('whoami'); ?>

exec('whoami') will do this

<?php
echo exec('whoami');
?>

Kind of backward way, but without exec/system:

file_put_contents("testFile", "test");
$user = fileowner("testFile");
unlink("testFile");

If you create a file, the owner will be the PHP user.

This could also likely be run with any of the temporary file functions such as tempnam(), which creates a random file in the temporary directory and returns the name of that file. If there are issues due to something like the permissions, open_basedir or safe mode that prevent writing a file, typically, the temp directory will still be allowed.

You can try using backticks like this:

echo `whoami`;

<?php phpinfo(); ?>

save as info.php and

open info.php in your browser

ctrl+f then type any of these:

APACHE_RUN_USER
APACHE_RUN_GROUP
user/group

you can see the user and the group apache is running as.

I usually use

<?php echo get_current_user(); ?>

I will be glad if it helped you

Straight from the shell you can run:

php -r "echo exec('whoami');"

In my setup I want to check if the current process has permission to create folders, subfolders and files before I begin a process and suggest a solution if it looks like I can't. I wanted to run stat(<file>) on various things to ensure the permissions match those of the running process (I'm using php-fpm so it varies depending on the pool).
The posix based solution Mario gave above, seems perfect, however it seems the posix extension is --disabled so I couldn't do the above and as I want to compare the results with the response from running stat() running whoami in a separate shell isn't helpful either (I need the uid and gid not the username).

However I found a useful hint, I could stat(/proc/self) and stat(/proc/self/attr) and see the uid and gid of the file.

Hope that helps someone else