.htaccess redirect all requests to perl file - .htaccess

Question

I want to redirect all requests to a perl file which is supposed to handle them depending on the sub domain.
I tried using this .htaccess:
Options +ExecCGI
AddHandler fcgid-script .pl
RewriteEngine On
RewriteCond %{HTTP_HOST} ^(.+?)\.example\.com$
RewriteRule ^(.*)$ /%1/main.pl/$1 [L]
I would expect that, if I try to open master.example.com that my ~/html-root/master/main.pl would get executed, but instead I get an "Internal Server Error".
Apache's error_log says
[Wed Jan 20 18:06:36 2016] [error] [client xxx.xxx.xxx.xxx] Request exceeded the limit of 10 internal redirects due to probable configuration error. Use 'LimitInternalRecursion' to increase the limit if necessary. Use 'LogLevel debug' to get a backtrace., referer: http://master.example.com/
If I try to visit example.com/master/main.pl my script gets executed just fine.
What am I doing wrong?

Answer 1

Try your rule this way,
Options +ExecCGI
AddHandler fcgid-script .pl
RewriteEngine On
RewriteCond %{HTTP_HOST} ^(.+?)\.example\.com$
RewriteCond %1::%{REQUEST_URI} !^(.*?)::/\1/? [NC]
RewriteRule ^(.*)$ /%1/main.pl/$1 [L]

Answer 2

I have found sort of a workaround:
Options +ExecCGI
AddHandler fcgid-script .pl
RewriteEngine On
RewriteCond %{ENV:REDIRECT_ENV} !^.+$
RewriteCond %{HTTP_HOST} ^(.+?)\.example\.com$
RewriteRule ^(.*)$ /%1/main.pl/$1 [L,E=ENV:%1]
Instead of not redirecting requests to /\1/main.pl I set an environment variable on the first redirect. If that variable is set, I don't do any more redirects thus getting out of the infinite loop that otherwise would be happening.