#!/usr/bin/perl -w

# luksformat - wrapper around LUKS-capable cryptsetup and mkfs for easy
# creation of an encrypted device.
#
# (C) 2005 Canonical Ltd.
# Author: Martin Pitt <martin.pitt@ubuntu.com>
# License: GNU General Public License, v2 or any later
# (http://www.gnu.org/copyleft/gpl.html)

use Getopt::Long;

sub help() {
    print "luksformat - Create and format an encrypted LUKS device
Usage: luksformat [-t <file system>] <device>\n";
    exit 1;
}

# default file system
$fs = 'vfat';
exit 1 unless GetOptions ('t|type=s' => \$fs);

help() if $#ARGV != 0;

if ($> != 0) {
    print STDERR "This program needs to be started as root\n";
    exit 1;
}

$device = $ARGV[0];

$mkfs = "/sbin/mkfs.$fs";
if (! -x $mkfs) {
    print STDERR "Error: invalid file system: $fs\n";
    exit 1;
}

# generate temporary mapped device name which is not yet used
$name = "";
for ($i = 1; $i < 100; $i++) {
    if (! -e "/dev/mapper/luksformat$i") {
	$name = "luksformat$i";
	last;
    }
}

$name or die "Error: could not generate temporary mapped device name";

# we do not need to be overly concerned with race conditions here, cryptsetup
# will just fail if the name already exists now.
print "Creating encrypted device on $device...\n";
if ((system 'cryptsetup', 'luksFormat', '-c', 'aes-lrw-benbi', '-y', '-s', '384', $device)) {
    die "Could not create LUKS device $device";
}

print "Please enter your passphrase again to verify it\n";
if ((system 'cryptsetup', 'luksOpen', $device, $name) != 0) {
    print STDERR "The passphrases you entered were not identical\n";
    exit 1;
}

$result = system $mkfs, "/dev/mapper/$name";
print "\n";
system 'cryptsetup', 'luksClose', $name;

die "Could not format device with file system $fs" if $result;

__END__

=head1 NAME

luksformat - Create and format an encrypted LUKS device 

=head1 SYNOPSIS

B<luksformat> [B<-t> I<fstype>] I<device>

=head1 DESCRIPTION

B<luksformat> is a wrapper around B<cryptsetup> and B<mkfs> which provides an
easy interface for creating an encrypted device that follows the LUKS standard
and for putting a file system onto the encrypted device.

The default file system is B<vfat> since that is most commonly used on
removable devices. However, you can specify any available file system with the
B<-t> option.

=head1 SEE ALSO

L<cryptsetup(8)>, L<mkfs(8)>

=head1 AUTHOR

This program was written by Martin Pitt <martin.pitt@ubuntu.com>.