#!/bin/sh -
#
#   Script to generate good passwords (i.e. random and non-reproducible),
#   among other things.  Type "genpwd -h" for usage information.
#   Works on FreeBSD.  For other systems, you might have to change
#   a few of the *stat calls.
#
#   Copyright (C) 2001 Oliver Fromme <olli@fromme.com> <olli@secnetix.de>
#   2-clause BSD-style license and disclaimer applies.
#

PATH=/bin:/usr/bin:/sbin:/usr/sbin

CDEF="lludds"
NDEF=8
WDEF=8

Usage()
{
	ME=`basename $0`
	cat <<-tac >&2

	Usage:  $ME [-luds] [-c <chars>] [-n <num>] [-w <width>]
	   -l           include lowercase letters
	   -u           include uppercase letters
	   -d           include digits
	   -s           include special characters
	   -c <chars>   include characters from <chars>
	   -n <num>     print <num> passwords (default: $NDEF)
	   -w <width>   make <width> characters per passwords (default: $WDEF)
	   -m           separate by spaces instead of newlines
	Repeat an option to use more of this kind of characters.
	The default is -$CDEF.

	Examples of advanced uses:
	If you're upset, use this command to express your feelings:
	   $ME -w4 -n30 -cargl
	To generate a labyrinth, try this one:
	   $ME -w20 -n20 -c'/\'

	tac
	exit 1
}

CUSE=""
NUSE=$NDEF
WUSE=$WDEF
CADD=""
NEWL=1

#
#   The following emulates pretty well the standard UNIX
#   parsing of command line options and arguments.
#
while [ $# -gt 0 ]; do
	if [ "$GETC" = 1 ]; then
		CADD="$1$CADD"
		GETC=0
		shift
		continue
	fi
	if [ "$GETN" = 1 ]; then
		NUSE="$1"
		GETN=0
		shift
		continue
	fi
	if [ "$GETW" = 1 ]; then
		WUSE="$1"
		GETW=0
		shift
		continue
	fi
	OPT="$1"
	if ! expr "x$OPT" : 'x-.[^-]*$' >/dev/null; then
		break	# End of option parsing.
	fi
	while :; do
		OPT=`expr "x$OPT" : 'x.\(.*\)$'`
		case "$OPT" in
			"")
				shift
				break		# End of this option string.
				;;
			[luds]*)
				CUSE=`expr "$OPT" : '\(.\)'`$CUSE
				;;
			m*)
				NEWL=0
				;;
			c)
				GETC=1
				;;
			c?*)
				CADD=`expr "x$OPT" : 'x.\(.*\)$'`"$CADD"
				OPT=""
				;;
			n)
				GETN=1
				;;
			n?*)
				NUSE=`expr "x$OPT" : 'x.\(.*\)$'`"$CADD"
				OPT=""
				;;
			w)
				GETW=1
				;;
			w?*)
				WUSE=`expr "x$OPT" : 'x.\(.*\)$'`"$CADD"
				OPT=""
				;;
			-)
				shift
				break 2		# End of option parsing.
				;;
			*)
				echo "\"$OPT\""
				Usage
				;;
		esac
	done
done
if [ $# -gt 0 -o "$GETC" = 1 -o "$GETN" = 1 -o "$GETW" = 1 ]; then
	# Some non-option arguments left, or option arguments missing.
	Usage
fi

if ! expr "$NUSE" : '[0-9][0-9]*$' >/dev/null; then
	# Not an integer number.
	Usage
fi
if ! expr "$WUSE" : '[0-9][0-9]*$' >/dev/null; then
	# Not an integer number.
	Usage
fi
if [ $WUSE -lt 1 ]; then
	Usage
fi

if [ -z "$CUSE" -a -z "$CADD" ]; then
	CUSE=$CDEF
fi
export CUSE CADD NUSE WUSE NEWL

I=0
MAXBLA=`expr \( $NUSE \* $WUSE + 15 \) / 16`
while [ $I -lt $MAXBLA ]; do
	{
		# Generate some non-reproducible "randomness" ...
		echo $$
		if [ -r /dev/urandom ]; then
			dd if=/dev/urandom bs=16 count=1 2>/dev/null
		elif [ -r /dev/random ]; then
			dd if=/dev/random bs=16 count=1 2>/dev/null
		fi
		netstat -na
		netstat -bin
		netstat -s
		netstat -m
		ps -auxww
		iostat
		vmstat
		vmstat -i
		vmstat -s
		vmstat -m
		vmstat -z
		pstat -f
		pstat -t
	} 2>/dev/null \
	| md5
	I=`expr $I + 1`
done \
| awk '
	BEGIN {
		nuse = ENVIRON["NUSE"];
		wuse = ENVIRON["WUSE"];
		cuse = ENVIRON["CUSE"];
		cset = ENVIRON["CADD"];
		newl = ENVIRON["NEWL"];
		for (i = 1; i <= length(cuse); i++) {
			ch = substr(cuse, i, 1);
			if (ch == "l")
				cset = "abcdefghijkmnpqrstuvwxyz" cset;
			else if (ch == "u")
				cset = "ABCDEFGHJKLMNPQRSTUVWXYZ" cset;
			else if (ch == "d")
				cset = "23456789" cset;
			else
				cset = "!@#$%&*-+=/." cset;
		}
		clen = length(cset);
		for (i = 0; i < 256; i++) {
			ch = substr(cset, 1 + i % clen, 1);
			c[sprintf("%02x", i)] = ch;
			c[sprintf("%02X", i)] = ch;
		}
		ccount = 0;
		lcount = 0;
	}
	{
		while ($0 ~ /^[0-9A-Fa-f][0-9A-Fa-f]/) {
			if (lcount >= nuse)
				exit;
			printf "%c", c[substr($0, 1, 2)];
			if (++ccount % wuse == 0) {
				printf (newl ? "\n" : " ");
				lcount++;
			}
			$0 = substr($0, 3);
		}
	}
	END {
		if (ccount % wuse != 0 || !newl)
			printf "\n";
	}
'

#--