pw_rand.c

/*
 * pw_rand.c --- generate completely random (and hard to remember)
 * 	passwords
 *
 * Copyright (C) 2001,2002 by Theodore Ts'o
 * 
 * This file may be distributed under the terms of the GNU Public
 * License.
 */

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include "pwgen.h"

const char *pw_digits = "0123456789";
const char *pw_uppers = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
const char *pw_lowers = "abcdefghijklmnopqrstuvwxyz";
const char *pw_symbols = "!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~";
const char *pw_ambiguous = "B8G6I1l0OQDS5Z2";
const char *pw_vowels = "01aeiouyAEIOUY";

void pw_rand(char *buf, int size, int pw_flags)
{
	char		ch, *chars, *wchars;
	int		i, len, feature_flags;

	len = 0;
	if (pw_flags & PW_DIGITS) {
		len += strlen(pw_digits);
	}
	if (pw_flags & PW_UPPERS) {
		len += strlen(pw_uppers);
	}
	len += strlen(pw_lowers);
	if (pw_flags & PW_SYMBOLS) {
		len += strlen(pw_symbols);
	}
        chars = malloc(len+1);
        if (!chars) {
		fprintf(stderr, "Couldn't malloc pw_rand buffer.\n");
		exit(1);
	}
	wchars = chars;
	if (pw_flags & PW_DIGITS) {
		strcpy(wchars, pw_digits);
		wchars += strlen(pw_digits);
	}
	if (pw_flags & PW_UPPERS) {
		strcpy(wchars, pw_uppers);
		wchars += strlen(pw_uppers);
	}
	strcpy(wchars, pw_lowers);
	wchars += strlen(pw_lowers);
	if (pw_flags & PW_SYMBOLS) {
		strcpy(wchars, pw_symbols);
	}
try_again:
	len = strlen(chars);
	feature_flags = pw_flags;
	i = 0;
	while (i < size) {
		ch = chars[pw_number(len)];
		if ((pw_flags & PW_AMBIGUOUS) && strchr(pw_ambiguous,ch))
			continue;
		if ((pw_flags & PW_NO_VOWELS) && strchr(pw_vowels, ch))
			continue;
		buf[i++] = ch;
		if (strchr(pw_digits, ch))
			feature_flags &= ~PW_DIGITS;
		if (strchr(pw_uppers, ch))
			feature_flags &= ~PW_UPPERS;
		if (strchr(pw_symbols, ch))
			feature_flags &= ~PW_SYMBOLS;
	}
	if (feature_flags & (PW_UPPERS | PW_DIGITS | PW_SYMBOLS))
		goto try_again;
	buf[size] = 0;
	free(chars);
	return;
}