.htaccess rewrite: subdomain as GET var and path as GET var

Question

Desired result:

http://example.com/                 -> index.php
http://www.example.com/             -> index.php
http://hello.example.com/           -> index.php?subdomain=hello
http://whatever.example.com/        -> index.php?subdomain=whatever
http://example.com/world            -> index.php?path=world
http://example.com/world/test       -> index.php?path=world/test
http://hello.example.com/world/test -> index.php?subdomain=hello&path=world/test

With the .htaccess I have right now, I can achieve one or the other re-mapping, but not both at the same time.

RewriteEngine On

# Parse the subdomain as a variable we can access in PHP, and
# run the main index.php script
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{HTTP_HOST}        !^www
RewriteCond %{HTTP_HOST}         ^([^\.]+)\.([^\.]+)\.([^\.]+)$
RewriteRule ^.*$ index.php?subdomain=%1

# Map all requests to the 'path' get variable in index.php
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php?path=$1 [L] 

I'm having a hard time combining the two...any pointers, please?

EDIT
The unwanted behavior I'm experiencing now is that if I have a subdomain and a path after .com/, only the subdomain will be passed through, ie:

http://hello.example.com/world-> index.php?subdomain=hello

Answer 1

Use the first rule to add the subdomain parameter, without changing the URI, then use the 2nd rule to route the URI to index.php:

RewriteEngine On

# Parse the subdomain as a variable we can access in PHP, and
# run the main index.php script
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{HTTP_HOST}        !^www
RewriteCond %{HTTP_HOST}         ^([^\.]+)\.([^\.]+)\.([^\.]+)$
RewriteRule ^(.*)$ /$1?subdomain=%1

# Map all requests to the 'path' get variable in index.php
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php?path=$1 [L,QSA] 

The second rule needs to have the QSA flag, otherwise the first rule's query string gets lost.