/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */


/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*
 *      A one-rotor machine designed along the lines of Enigma
 *      but considerably trivialized.
 */

#define ECHO 010
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <crypt.h>
#include <errno.h>

#define ROTORSZ 256
#define MASK 0377
char    t1[ROTORSZ];
char    t2[ROTORSZ];
char    t3[ROTORSZ];

static void
setup(pw)
char *pw;
{
        int ic, i, k, temp;
        unsigned random;
        char buf[13];
        long seed;
        char *ret;
        int err;

        (void) strncpy(buf, pw, 8);
        buf[8] = buf[0];
        buf[9] = buf[1];
        errno = 0;
        ret = des_crypt(buf, &buf[8]);
        if (ret == NULL) {
                err = errno;
                (void) fprintf(stderr, "crypt: setup failed, unable to"
                    " initialize rotors: %s\n", strerror(err));
                exit(1);
        }
        (void) strncpy(buf, ret, 13);
        seed = 123;
        for (i = 0; i < 13; i++)
                seed = seed*buf[i] + i;
        for (i = 0; i < ROTORSZ; i++) {
                t1[i] = i;
                t3[i] = 0;
        }
        for (i = 0; i < ROTORSZ; i++) {
                seed = 5*seed + buf[i%13];
                random = seed % 65521;
                k = ROTORSZ-1 - i;
                ic = (random&MASK)%(k+1);
                random >>= 8;
                temp = t1[k];
                t1[k] = t1[ic];
                t1[ic] = temp;
                if (t3[k] != 0) continue;
                ic = (random&MASK) % k;
                while (t3[ic] != 0) ic = (ic+1) % k;
                t3[k] = ic;
                t3[ic] = k;
        }
        for (i = 0; i < ROTORSZ; i++)
                t2[t1[i]&MASK] = i;
}

int
main(int argc, char **argv)
{
        extern int optind;
        char *p1;
        int i, n1, n2, nchar;
        int c;
        struct {
                long offset;
                unsigned int count;
        } header;
        int pflag = 0;
        int kflag = 0;
        char *buf;
        char key[8];
        char keyvar[] = "CrYpTkEy=XXXXXXXX";
        char *s;

        if (argc < 2) {
                if ((buf = (char *)getpass("Enter key:")) == NULL) {
                        (void) fprintf(stderr, "Cannot open /dev/tty\n");
                        exit(1);
                }
                setup(buf);
        } else {
                while ((c = getopt(argc, argv, "pk")) != EOF)
                        switch (c) {
                        case 'p':
                        /* notify editor that exec has succeeded */
                                if (write(1, "y", 1) != 1)
                                        exit(1);
                                if (read(0, key, 8) != 8)
                                        exit(1);
                                setup(key);
                                pflag = 1;
                                break;
                        case 'k':
                                if ((s = getenv("CrYpTkEy")) == (char *)NULL) {
                                        (void) fprintf(stderr,
                                            "CrYpTkEy not set.\n");
                                        exit(1);
                                }
                                (void) strncpy(key, s, 8);
                                setup(key);
                                kflag = 1;
                                break;
                        case '?':
                                (void) fprintf(stderr,
                                    "usage: crypt [ -k ] [ key]\n");
                                exit(2);
                        }
                if (pflag == 0 && kflag == 0) {
                        (void) strncpy(keyvar+9, argv[optind], 8);
                        (void) putenv(keyvar);
                        (void) execlp("crypt", "crypt", "-k", 0);
                }
        }
        if (pflag)
                for (;;) {
                        if ((nchar = read(0, (char *)&header, sizeof (header)))
                            != sizeof (header))
                                exit(nchar);
                        n1 = (int)(header.offset&MASK);
                        n2 = (int)((header.offset >> 8) &MASK);
                        nchar = header.count;
                        buf = (char *)malloc(nchar);
                        p1 = buf;
                        if (read(0, buf, nchar) != nchar)
                                exit(1);
                        while (nchar--) {
                                *p1 = t2[(t3[(t1[(*p1 + n1)&MASK]+
                                    n2)&MASK] - n2)&MASK] - n1;
                                n1++;
                                if (n1 == ROTORSZ) {
                                        n1 = 0;
                                        n2++;
                                        if (n2 == ROTORSZ) n2 = 0;
                                }
                                p1++;
                        }
                        nchar = header.count;
                        if (write(1, buf, nchar) != nchar)
                                exit(1);
                        free(buf);
                }

        n1 = 0;
        n2 = 0;

        while ((i = getchar()) >= 0) {
                i = t2[(t3[(t1[(i+n1)&MASK]+n2)&MASK]-n2)&MASK]-n1;
                (void) putchar(i);
                n1++;
                if (n1 == ROTORSZ) {
                        n1 = 0;
                        n2++;
                        if (n2 == ROTORSZ) n2 = 0;
                }
        }
        return (0);
}