Extend mod_setenvif to support specifying regular expressions

Changes with Apache 2.0.19-dev

  *) Extend mod_setenvif to support specifying regular expressions

     on the SetEnvIf (and SetEnvIfNoCase) directive attribute field.

     Example:  SetEnvIf ^TS*  [a-z].* HAVE_TS 

     will cause HAVE_TS to be set if any of the request headers begins 

     with "TS" and has a value that begins with any character in the

     set [a-z]. [Bill Stoddard]

  *) httpd children now re-bind themselves to a random CPU on

     multiprocessor systems on AIX via bindprocessor() in 2.0.

     [Victor J. Orlikowski]

   scope.</STRONG>

  </BLOCKQUOTE>

  <P>

  <EM>attribute</EM> may be a regular expression when used to match a request header.

  If <EM>attribute</EM> is a regular expression and it doesn't match any of the

  request's header names, then <EM>attribute</EM> is not tested against the request's

  environment variable list.

  </P>

  <P>

  Example:

  </P>

  <PRE>

   SetEnvIf Referer www\.mydomain\.com intra_site_referral

        :

   SetEnvIf object_is_image xbm XBIT_PROCESSING=1

        :

   SetEnvIf ^TS*  ^[a-z].*  HAVE_TS

  </PRE>

  <P>

  The first three will set the environment variable <SAMP>object_is_image</SAMP> if the

  <SAMP>intra_site_referral</SAMP> if the referring page was somewhere

  on the <SAMP>www.mydomain.com</SAMP> Web site.

  </P>

  <P>

  The last example will set environment variable <SAMP>HAVE_TS</SAMP> if the request

  contains any headers that begin with "TS" whose values begins with any character

  in the set [a-z].

  </P>

  <HR> <!-- the HR is part of the directive description -->

  <H2>

   <A NAME="SetEnvIfNoCase">SetEnvIfNoCase directive

 *   SetEnvIf name regex var ...

 *

 * where name is either a HTTP request header name, or one of the

 * special values (see below). The 'value' of the header (or the

 * value of the special value from below) are compared against the

 * regex argument. If this is a simple string, a simple sub-string

 * special values (see below). 'name' may be a regex when it is used

 * to specify an HTTP request header name. The 'value' of the header 

 & (or the value of the special value from below) are compared against

 * the regex argument. If this is a simple string, a simple sub-string

 * match is performed. Otherwise, a request expression match is

 * done. If the value matches the string or regular expression, the

 * environment variables listed as var ... are set. Each var can 

 * This could be written as:

 *

 *    SetEnvIf remote_addr (127.0.0.1|192.168.10.) LOCAL

 *

 * To set HAVE_TS if the client request contains any header beginning

 * with "TS" with a value beginning with a lower case alphabet:

 *

 *    SetEnvIf ^TS* ^[a-z].* HAVE_TS

 */

#include "apr.h"