/*
 *  SPL - The SPL Programming Language
 *  Copyright (C) 2004, 2005  Clifford Wolf <clifford@clifford.at>
 *
 *  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
 *
 *  mod_crypt.c: A simple frontend to the C crypt() function
 */

/**
 * A crypt() function (like in C).
 */

#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>

#include "spl.h"
#include "compat.h"

extern void SPL_ABI(spl_mod_crypt_init)(struct spl_vm *vm, struct spl_module *mod, int restore);
extern void SPL_ABI(spl_mod_crypt_done)(struct spl_vm *vm, struct spl_module *mod);

/**
 * This function is a frontend to the C crypt() function. If salt is not given
 * or shorten then 2 characters then a random salt ([a-zA-Z0-9./]{2}) is used.
 */
// builtin crypt(key, salt)
static struct spl_node *handler_crypt(struct spl_task *task, void UNUSED(*data))
{
	char *key = spl_clib_get_string(task);
	char *salt = spl_clib_get_string(task);
	char saltset[] = "abcdefghijklmnnopqrstuvwxyzABCDEFGHIJKLMNNOPQRSTUVWXYZ0123456789./";
	unsigned char random_byte;
	char random_salt[12];
	int generate_md5 = 0;
	int i;

	if (strlen(salt) == 3 && !strcmp(salt, "$1$"))
		generate_md5 = 1;

	if (generate_md5 || strlen(salt) < 2)
	{
		int fd = open("/dev/urandom", O_RDONLY);

		if (generate_md5) {
			random_salt[0] = salt[0];
			random_salt[1] = salt[1];
			random_salt[2] = salt[2];

			for (i=3; i<11; i++) {
				if (fd >= 0) {
					read(fd, &random_byte, 1);
					random_salt[i] = saltset[random_byte % sizeof(saltset)];
				} else
					random_salt[i] = 'X';
			}

			random_salt[11] = 0;
		} else {
			if (fd >= 0) {
				read(fd, &random_byte, 1);
				random_salt[0] = saltset[random_byte % sizeof(saltset)];
				read(fd, &random_byte, 1);
				random_salt[1] = saltset[random_byte % sizeof(saltset)];
			} else {
				random_salt[0] = 'X';
				random_salt[1] = 'X';
			}

			random_salt[2] = 0;
		}

		if (fd >= 0)
			close(fd);
		salt = random_salt;
	}

	return SPL_NEW_STRING_DUP(crypt(key, salt));
}

void SPL_ABI(spl_mod_crypt_init)(struct spl_vm *vm, struct spl_module UNUSED(*mod), int UNUSED(restore))
{
	spl_clib_reg(vm, "crypt", handler_crypt, 0);
}

void SPL_ABI(spl_mod_crypt_done)(struct spl_vm UNUSED(*vm), struct spl_module UNUSED(*mod))
{
	return;
}