From the [apache documentation](http://httpd.apache.org/docs/2.2/custom-error.html), it seems that the environment variable `REDIRECT_URL` will carry the name of the page the user has accessed. Also see [ErrorDocument](http://httpd.apache.org/docs/2.2/mod/core.html#errordocument)'s documentation.
From the [apache documentation](http://httpd.apache.org/docs/2.2/custom-error.html), it seems that the environment variable `REDIRECT_URL` will carry the name of the page the user has accessed. Also see [ErrorDocument](http://httpd.apache.org/docs/2.2/mod/core.html#errordocument)'s documentation.