Provided by: libsafe-hole-perl_0.13-1build1_amd64 bug


       Safe::Hole - make a hole to the original main compartment in the Safe compartment


         use Safe;
         use Safe::Hole;
         $cpt = new Safe;
         $hole = new Safe::Hole {};
         sub test { Test->test; }
         $Testobj = new Test;
         # $cpt->share('&test');  # alternate as next line
         $hole->wrap(\&test, $cpt, '&test');
         # ${$cpt->varglob('Testobj')} = $Testobj;  # alternate as next line
         $hole->wrap($Testobj, $cpt, '$Testobj');
         $cpt->reval('test; $Testobj->test;');
         print $@ if $@;
         package Test;
         sub new { bless {},shift(); }
         sub test { my $self = shift; $self->test2; }
         sub test2 { print "Test->test2 called\n"; }


         We can call outside defined subroutines from the Safe compartment
       using share(), or can call methods through the object that is copied
       into the Safe compartment using varglob(). But that subroutines or
       methods are executed in the Safe compartment too, so they cannot call
       another subroutines that are dinamically qualified with the package
       name such as class methods nor can they compile code that uses opcodes
       that are forbidden within the compartment.

         Through Safe::Hole, we can execute outside defined subroutines in the
       original main compartment from the Safe compartment.

         Note that if a subroutine called through Safe::Hole::call does a
       Carp::croak() it will report the error as having occured within
       Safe::Hole.  This can be avoided by including Safe::Hole::User in the
       @ISA for the package containing the subroutine.

       new [NAMESPACE]
           Class method. Backward compatible constructor.
             NAMESPACE is the alternate root namespace that makes the compartment in which call()
           method execute the subroutine.  Default of NAMESPACE means the current 'main'. This
           emulates the behaviour of Safe-Hole-0.08 and earlier.

       new \%arguments
           Class method. Constructor.
             The constructor is called with a hash reference providing the constructor arguments.
           The argument ROOT specifies the alternate root namespace for the object.  If the ROOT
           argument is not specified then Safe::Hole object will attempt restore as much as it
           can of the environment in which it was constrtucted.  This includes the opcode mask,
           %INC and @INC.  If a root namespace is specified then it would not make sense to
           restore the %INC and @INC from main:: so this is not done.  Also if a root namespace
           is given the opcode mask is not restored either.

       call $coderef [,@args]
           Object method.
             Call the subroutine refered by $coderef in the compartment that is specified with
           constructor new. @args are passed as the arguments to the called $coderef.  Note that
           the arguments are not currently passed by reference although this may change in a
           future version.

       wrap $ref [,$cpt ,$name]
           Object method.
             If $ref is a code reference, this method returns the anonymous subroutine reference
           that calls $ref using call() method of Safe::Hole (see above).
             If $ref is a class object, this method makes a wrapper class of that object and
           returns a new object of the wrapper class. Through the wrapper class, all original
           class methods called using call() method of Safe::Hole.
             If $cpt as Safe object and $name as subroutine or scalar name specified, this method
           works like share() method of Safe. When $ref is a code reference $name must like
           '&subroutine'. When $ref is a object $name must like '$var'.
             Name $name may not be same as referent of $ref. For example:
             $hole->wrap(\&foo, $cpt, '&bar');
             $hole->wrap(sub{...}, $cpt, '&foo');
             $hole->wrap($objfoo, $cpt, '$objbar');

           Object method.  Return the namespace that is specified with constructor new().  If no
           namespace was then root() returns 'main'.

       You MUST NOT share the Safe::Hole object with the Safe compartment. If you do it the Safe
       compartment is NOT safe.

       This module provides a means to go from a state where an opcode is denied back to a state
       where it is not.  Reasonable care has been taken to ensure that programs cannot simply
       manipulate the internals to the Safe::Hole object to reduce the opmask in effect.  However
       there may still be a way that the authors have not considered.  In particular it relies on
       the fact that a Perl program cannot change stuff inside the magic on a Perl variable.  If
       you install a module that allows a Perl program to fiddle inside the magic then this
       assuption breaks down.  One would hope that any system that was running un-trusted code
       would not have such a module installed.


       Sey Nakajima <> (Initial version)

       Brian McCauley <> (Maintenance)

       Todd Rinaldo <> (Maintenance)