#!/bin/sh -- # A comment mentioning perl, to prevent perl from looping. Indented to work with bash.
eval 'exec perl -S $0 ${1+"$@"}'
        if 0;

$debug = 0;
$devrandom = 0;
$decimal = 0;
$hex = 0;
$mac = 0;
$wep = 0;
$skipchars  = '';
$charlist = '';
$length = 8;
$quiet = 0;
$nmax = 0;
$unique = 0;
$ascii = 0;

@args = @ARGV;

chop($Program = `basename $0`);

$Usage = <<"END";

$Program: generate a random password from a seed.

Usage: $Program <options>

Options:
	-s <skipchars>		Characters to not use.
	-c <charlist>		Use charlist characters only.
	-a			"ascii", use [a-z0-9] only
	-A			"ascii", use [A-z0-9] only
	-l <n>			Length of passwd (default: $length)
	-u			Unique, do not repeat chars.
	-q,-n			Quiet (no echo) when prompting for seed.
	-D			Decimal digits only.
	-hex			Hexidecimal digits only.
	-mac			-hex and separate pairs of hex digits with ":"
	-N <n>			Use the first <n> chars of the list.
				A-Za-z0-9~!@#$%^&*(){}[]_+-=|:;,./<>?
	-x			use /dev/urandom for seeding.
	-d			Debug mode.

Notes:
	To get a random permutation of the alphabet do:
	rp -u -l 26 -N 26 <seed>

END

LOOP:	
while (@ARGV) {
    $_ = shift;
    CASE: {
	/^-s$/ && ($skipchars = shift, last CASE);
	/^-c$/ && ($charlist = shift, last CASE);
	/^-l$/ && ($length = shift, last CASE);
	/^-u$/ && ($unique = 1, last CASE);
	/^-a$/ && ($ascii = 1, last CASE);
	/^-A$/ && ($ascii = 2, last CASE);
	/^(-q|-n)$/ && ($quiet = 1, last CASE);
	/^-D$/ && ($decimal = 1, last CASE);
	/^-hex$/ && ($hex = 1, last CASE);
	/^-mac$/ && ($mac = 1, last CASE);
	/^-wep$/ && ($wep = 1, last CASE);
	/^-N$/ && ($nmax = shift, last CASE);
	/^-d$/ && ($debug = 1, last CASE);
	/^-x$/ && ($devrandom = 1, last CASE);
	/^--$/ && (last LOOP);	# -- means end of switches
	/^-(-.*)$/ && (unshift(@ARGV, $1), last CASE);
	/^(-h|-help)$/ && ((print STDERR $Usage), exit 0, last CASE);
	if ( /^-(..+)$/ ) {	# split bundled switches:
		local($y, $x) = ($1, '');
		foreach $x (reverse(split(//, $y))) { unshift(@ARGV,"-$x") };
		last CASE;
	}
	/^-/ && ((print STDERR "Invalid arg: $_\n$Usage"), exit 1, last CASE);
	unshift(@ARGV,$_);
	last LOOP;
    }
}

if ( $wep && ! $ENV{RP_WEP} ) {
	#easiest way...
	$ENV{RP_WEP} = 1;
	$args = join(' ', @args);
	$result = `$0 -hex -l 26 $args`;
	print STDOUT $result;
	$result =~ s/(....)/$1-/g;
	print STDOUT $result;
	exit 0;
}
if ( $mac && ! $ENV{RP_MAC} ) {
	#easiest way...
	$ENV{RP_MAC} = 1;
	$args = join(' ', @args);
	$result = `$0 -hex $args`;
	$result =~ s/(..)/$1:/g;
	$result =~ s/:$//;
	print STDOUT $result;
	exit 0;
}

&Initialize_List($skipchars);

select(STDERR); $| = 1;
select(STDOUT); $| = 1;

if ( $length !~ /^\d+$/ ) {
	print STDERR "$Usage";
	exit 1;
}

if ( $devrandom ) {
	my $rbytes;
	my $n = 8;
	my $file = '';
	if ( open(RAN, "</dev/urandom") ) {
		read(RAN, $rbytes, $n);
		$file = '/dev/urandom';
	} elsif ( open(RAN, "</dev/random") ) {
		read(RAN, $rbytes, $n);
		$file = '/dev/random';
	} else {
		die "$!";
	}
	close(RAN);
	if ( length($rbytes) != $n ) {
		die "bad data from: $file";
	}
	# print STDERR "rbytes: $rbytes\n";
	my $seed = join('', unpack("C$n", $rbytes));
	$seed = substr($seed, -9);
	# print STDERR "seed: $seed\n";
	push(@ARGV, $seed);
}

if ($ARGV[0] eq '-') {
	my $s = <STDIN>;
	chomp($s);
	$ARGV[0] = $s;
}

if ( $ARGV[0] eq '' ) {
	print STDERR "Please enter a seed number or phrase: ";
	if ( $quiet ) {
		$seed1 = &get_passwd();
		print STDERR "Enter it again: ";
		$seed2 = &get_passwd();
		if ( $seed1 ne $seed2 ) {
			print STDERR "Seeds differ. Exiting.\n";
			exit 1;
		}
		$seed = $seed1;
	} else {
		chop($seed = <STDIN>);
	}
} else {
	$seed = join(' ', @ARGV);
}

if ( $seed =~ /^\d*$/ ) {
	if ( $seed eq '' ) {
		srand();
	} else {
		srand($seed);
	}
} else {
	chop($x = `echo "$seed" | sum | awk '{print \$1}' 2>/dev/null`);
	chop($y = $seed);
	$y = $seed if $y eq '';
	chop($y = `echo "$y"    | sum | awk '{print \$1}' 2>/dev/null`);
	if ( $x =~ /^\d+$/ && $y =~ /^\d+$/ ) {
		$z = $x * $y;
		# print STDERR "(using seed $z)\n\n";
		srand($z);
	} else {
		# print STDERR "(not using seed $x * $y)\n\n";
		srand($seed);
	}
}

if ( $unique && $length > $Size )  {
	print STDERR "length too long: $length > $Size, resetting length to $Size\n";
	$length = $Size;
}

for ($i = 0; $i < $length; $i++) {
	$R = int(rand($Size)); 

	if ( $unique && $Hit{$R} ) {
		$i--;
		next;
	}
	$Hit{$R}++;
	print STDOUT $List[$R];
	
	$f = int(10*rand()) + 1;
	for ( $j=0; $j < $f; $j++) {
		$R = rand();
		# print STDERR "." if $debug;
	}
}
print STDOUT "\n";

exit 0;

sub Initialize_List {

	local($skip) = @_;

	local(@List0, $item);

	if ( $charlist ne '' ) {
	    @List0 = split(//, $charlist);

	} elsif ( $ascii == 1 ) {
	    @List0 = qw '
		a b c d e f g h i j k l m n o p q r s t u v w x y z 
		1 2 3 4 5 6 7 8 9 0 
		';
		
	} elsif ( $ascii == 2 ) {
	    @List0 = qw '
		A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
		a b c d e f g h i j k l m n o p q r s t u v w x y z 
		1 2 3 4 5 6 7 8 9 0 
		';
		
	} elsif ( $decimal ) {
	    @List0 = qw '
		1 2 3 4 5 6 7 8 9 0 
		';

	} elsif ( $hex ) {
	    @List0 = qw '
		1 2 3 4 5 6 7 8 9 0 a b c d e f
		';

	} else {
		
	    @List0 = qw '
		A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 
		a b c d e f g h i j k l m n o p q r s t u v w x y z 
		1 2 3 4 5 6 7 8 9 0 
		~ ! @ # $ % ^ & * ( ) { } [ ] _ + - = | : ; , . / < > ? 
		';
	}

	$skip =~ s/(\W)/\\$1/g;
	#print STDERR "skip: $skip\n";
	$cnt = 0;
	foreach $item (@List0) {
		$cnt++;
		if ( $nmax > 0 && $cnt > $nmax ) {
			# print STDERR "last item is: $item\n";
			last;
		}
		next if $skip ne '' && $item =~ /[$skip]/;
		push (@List, $item);
	}

	$Size = @List;

	if ( $debug ) {
		for ($i = 0; $i < $Size; $i++) {
			print STDERR "$i: $List[$i]\n";
		}
	}

}


sub get_passwd {	# prompt for a password w/o echoing.

	local($input) = '';
	system("stty -echo");
	chop($input=<STDIN>);
	print "\n";
	system("stty echo");
	return $input;
}

__END__