mod_ruid2 is a suexec module for apache 2.0, 2.2 and 2.4, based on mod_ruid and mod_suid2

-it runs only on Linux because only the Linux kernel has implemented the required process capabilities.
-it has better performance than mod_suid2 because it doesn`t need to kill httpd children
 after one request. it makes use of kernel capabilites and after receiving a new request suids again.
-there are some security issues, for instance if attacker successfully exploits the httpd process,
 he can set effective capabilities and setuid to root. i recommend to use some security patch in kernel (grsec),
 or something..

-there are two main operation modes: stat and config
 1. config
 is default, you must define uid and gid. If no [ug]id is defined the default user and group are used.

 2. stat
 httpd setuid and setgid to uid and gid of requested filename(script)/directory
 this is good if you use mod_vhost_alias for virtual hosting

 1. download and install latest libcap from here
 2. run /apachedir/bin/apxs -a -i -l cap -c mod_ruid2.c
 3. configure httpd.conf
 4. restart apache

 RMode config|stat (default is config)
 RUidGid user|#uid group|#gid - when RMode is config, set to this uid and gid

 RMinUidGid user|#uid group|#gid - when uid/gid is < than min uid/gid set to default uid/gid
 RDefaultUidGid user|#uid group|#gid

 RGroups group1 group2 - additional groups set via setgroups
 @none - clear all previous defined groups.

 RDocumentChrRoot - Set chroot directory and the document root inside


 LoadModule ruid2_module   modules/mod_ruid2.so
 User                     apache
 Group                    apache
 RMode                    stat
 RGroups                  apachetmp
 RDocumentChRoot          /home /example.com/public_html

 <VirtualHost example.com>
   ServerAdmin    webmaster@example.com
   RDocumentChRoot /home /example.com/public_html
   ServerName     example.com
   ServerAlias    www.example.com
   RMode          config		# unnecessary since config is the default
   RUidGid        user1 group1
   RGroups        apachetmp

   <Directory /home/example.com/public_html/dir>
       RMode stat

   <Directory /home/example.com/public_html/dir/test>
       RMode config
       RUidGid user2 group2
       RGroups groups1

   <Directory /home/example.com/public_html/dir/test/123>
       RUidGid user3 group3

   <Location /yustadir>
       RMode config
       RUidGid user4 user4
       RGroups groups4


 <VirtualHost example.net>
   ServerAdmin    webmaster@example.net
   DocumentRoot   /home/example.net/public_html
   ServerName     example.net
   ServerAlias    www.example.net