# NAME

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

# SYNOPSIS

    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"; }

# DESCRIPTION

    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 dynamically 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 occurred within
  Safe::Hole.  This can be avoided by including Safe::Hole::User in the
  @ISA for the package containing the subroutine.

## Methods

- 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 constructed.  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 referred to 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');

- root

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

## Warning

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
assumption breaks down.  One would hope that any system that was
running un-trusted code would not have such a module installed.

# AUTHORS

Sey Nakajima <nakajima@netstock.co.jp> (Initial version)

Brian McCauley <nobull@cpan.org> (Maintenance)

Todd Rinaldo <toddr@cpan.org> (Maintenance)

# SEE ALSO

Safe(3).