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GnuPG/Tie.pm  view on Meta::CPAN

#
#    GnuPG.pm - Abstract tied interface to the GnuPG.
#
#    This file is part of GnuPG.pm.
#
#    Author: Francis J. Lacoste <francis.lacoste@Contre.COM>
#
#    Copyright (C) 1999, 2000 iNsu Innovations Inc.
#    Copyright (C) 2001 Francis J. Lacoste
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
package GnuPG::Tie;

use GnuPG;
use Symbol;

use Carp;

use Fcntl;

use strict;

sub TIEHANDLE {
    my $class = shift;
    $class = ref $class || $class;

    my ($gpg_in, $gpg_out)  = ( gensym, gensym );
    my ($tie_in,$tie_out)   = ( gensym, gensym );
    pipe $gpg_in, $tie_out
      or croak "error while creating pipe: $!";
    pipe $tie_in, $gpg_out
      or croak "error while creating pipe: $!";

    # Unbuffer writer pipes
    for my $fd ( ($gpg_out, $tie_out) ) {
	my $old = select $fd;
	$| = 1;
	select $old;
    }

    # Keep pipes open after exec
    # Removed close on exec from all file descriptor
    for my $fd ( ( $gpg_in, $gpg_out, $tie_in, $tie_out ) ) {
	fcntl( $fd, F_SETFD, 0 )
	  or croak "error removing close on exec flag: $!\n" ;
    }

    # Operate in non blocking mode
    for my $fd ( $tie_in, $tie_out ) {
	my $flags = fcntl $fd, F_GETFL, 0
	  or croak "error getting flags on pipe: $!\n";
	fcntl $fd, F_SETFL, $flags | O_NONBLOCK
	  or croak "error setting non-blocking IO on pipe: $!\n";
    }

    my $self = bless { reader	    => $tie_in,
		       writer	    => $tie_out,
		       done_writing => 0,
		       buffer	    => "",
		       len	    => 0,
		       offset	    => 0,
		       line_buffer  => "",
		       eof	    => 0,
		       gnupg	    => new GnuPG( @_ ),
		     }, $class;

    # Let subclass call the appropriate method and set
    # up the GnuPG object.
    $self->run_gnupg( @_,
		      input	=> $gpg_in,
		      output	=> $gpg_out,
		      tie_mode	=> 1,
		    );
    close $gpg_in;
    close $gpg_out;

    return $self;
}

sub WRITE {
    my ( $self, $buf, $len, $offset ) = @_;

    croak "attempt to read on a closed file handle\n"
      unless defined $self->{writer};

    croak ( "can't write after having read" ) if $self->{done_writing};

    my ( $r_in, $w_in ) = ( '', '' );
    vec( $r_in, fileno $self->{reader}, 1) = 1;
    vec( $w_in, fileno $self->{writer}, 1) = 1;

    my $left = $len;
    while ( $left ) {
	my ($r_out, $w_out) = ($r_in, $w_in);
	my $nfound = select $r_out, $w_out, undef, undef;
	croak "error in select: $!\n" unless defined $nfound;

	# Check if we can write
	if ( vec $w_out, fileno $self->{writer}, 1 ) {
	    my $n = syswrite $self->{writer}, $buf, $len, $offset;
	    croak "error on write: $!\n" unless defined $n;
	    $left -= $n;
	    $offset += $n;
	}
	# Check if we can read
	if ( vec $r_out, fileno $self->{reader}, 1 ) {
	    my $n = sysread $self->{reader}, $self->{buffer}, 1024,
	      $self->{len};
	    croak "error on read: $!\n" unless defined $n;
	    $self->{len} += $n;
	}
    }

    return $len;
}

sub done_writing() {
    my $self = shift;

    # Once we start reading, no other writing can be place
    # on the pipe. So we close the writer file descriptor
    unless ( $self->{done_writing} ) {
	$self->{done_writing} = 1;
	close $self->{writer}
	  or croak "error closing writer pipe: $\n";

	$self->postwrite_hook();
    }
}

sub READ {
    my $self = shift;
    my $bufref = \$_[0];
    my ( undef, $len, $offset ) = @_;

GnuPG/Tie.pm  view on Meta::CPAN

=head1 NAME

GnuPG::Tie::Encrypt - Tied filehandle interface to encryption with the GNU Privacy Guard.

GnuPG::Tie::Decrypt - Tied filehandle interface to decryption with the GNU Privacy Guard.

=head1 SYNOPSIS

    use GnuPG::Tie::Encrypt;
    use GnuPG::Tie::Decrypt;

    tie *CIPHER, 'GnuPG::Tie::Encrypt', armor => 1, recipient => 'User';
    print CIPHER <<EOF;
This is a secret
EOF
    local $/ = undef;
    my $ciphertext = <CIPHER>;
    close CIPHER;
    untie *CIPHER;

    tie *PLAINTEXT, 'GnuPG::Tie::Decrypt', passphrase => 'secret';
    print PLAINTEXT $ciphertext;
    my $plaintext = <PLAINTEXT>;

    # $plaintext should now contains 'This is a secret'
    close PLAINTEXT;
    untie *PLAINTEXT;

=head1 DESCRIPTION

GnuPG::Tie::Encrypt and GnuPG::Tie::Decrypt provides a tied  file handle
interface to encryption/decryption facilities of the GNU Privacy guard.

With GnuPG::Tie::Encrypt everyting you write to the file handle will be
encrypted. You can read the ciphertext from the same file handle.

With GnuPG::Tie::Decrypt you may read the plaintext equivalent of a
ciphertext. This is one can have been written to file handle.

All options given to the tie constructor will be passed on to the underlying
GnuPG object. You can use a mix of options to output directly to a file or
to read directly from a file, only remember than once you start reading
from the file handle you can't write to it anymore.

=head1 AUTHOR

Francis J. Lacoste <francis.lacoste@Contre.COM>

=head1 COPYRIGHT

Copyright (c) 1999, 2000 iNsu Innovations Inc.
Copyright (c) 2001 Francis J. Lacoste

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

=head1 SEE ALSO

gpg(1) GnuPG(3)

=cut