NAME

       File::Policy - Site policy for file I/O functions

SYNOPSIS

               use File::Policy;
               use File::Policy qw/check_safe/;   # to import a specific subroutine
               use File::Policy qw/:all/;         # to import all subroutines

               #Checking I/O policy
               check_safe($filename, 'r');
               check_safe($filename, 'w');

               #Preferred directory locations
               $logdir = get_log_dir();
               $tmpdir = get_temp_dir();

DESCRIPTION

       This defines the policy for file I/O with modules such as File::Slurp::WithinPolicy.  The
       purpose is to allow systems administrators to define locations and restrictions for
       applications' file I/O and give app developers a policy to follow.  Note that the module
       doesn't ENFORCE the policy - application developers can choose to ignore it (and systems
       administrators can choose not to install their applications if they do!).

       You may control which policy gets applied by creating a File::Policy::Config module with
       an IMPLEMENTATION constant. You may write your own policy as a module within the
       File::Policy:: namespace.

       By default (if no File::Policy::Config is present), the File::Policy::Default policy gets
       applied which doesn't impose any restrictions and provides reasonable default locations
       for temporary and log files.

       The motivation behind this module was a standard, flexible approach to allow a site wide
       file policy to be defined.  This will be most useful in large environments where a few
       sysadmins are responsible for code written by many other people.  Simply ensuring that
       submitted code calls check_safe() ensures file access is sane, reducing the amount of
       effort required to do a security audit.

       If your code is not security audit'd, or you are the only developer at your site, this
       might be overkill. However you may consider it good practise regardless and protection
       against paths in your code getting corrupted accidentally or maliciously in the future.

       There are two major benefits of using this module.  One, sites that do implement a policy
       can more easily integrate your code in a standard way.  If you have a file policy at your
       site, you can apply different policies (via File::Policy::Config) in different
       environments (production, integration test, development) and the appropriate policy is
       automatically applied without having to change your code or configs.

FUNCTIONS

       check_safe
                   check_safe( FILENAME , MODE );

           Checks FILENAME is safe - dies if not.  MODE is r (read) or w (write).

       get_temp_dir
                   $temporary_directory = get_temp_dir();

           Returns the path to temporary directory.  Note that any return value will have been
           cleared of a trailing slash.

       get_log_dir
                   $log_directory = get_log_dir();

           Returns the path to log directory.  Note that any return value will have been cleared
           of a trailing slash.

DEFINING YOUR OWN POLICY

       To implement your own custom policy

         cp File/Policy/Default.pm File/Policy/YourPolicy.pm

       and modify YourPolicy accordingly.  Then, create File/Policy/Config.pm containing:

         use constant IMPLEMENTATION => 'YourPolicy';

       Now having used File::Policy, calling check_safe in your scripts will enforce your policy
       (as well as give you access to log and temp paths in locations you recommend).

SEE ALSO

       File::Policy::Default, Safe

VERSION

       $Revision: 1.5 $ on $Date: 2005/05/18 15:58:21 $ by $Author: johna $

AUTHOR

       John Alden <cpan _at_ bbc _dot_ co _dot_ uk>

COPYRIGHT

       (c) BBC 2005. This program is free software; you can redistribute it and/or modify it
       under the GNU GPL.

       See the file COPYING in this distribution, or http://www.gnu.org/licenses/gpl.txt