src/scramble/scramble.cpp

   1 /*
   2  * Copyright (C) Volition, Inc. 1999.  All rights reserved.
   3  *
   4  * All source code herein is the property of Volition, Inc. You may not sell
   5  * or otherwise commercially exploit the source or things you created based on
   6  * the source.
   7  */
   8
   9 /*
  10  * $Logfile: /Freespace2/code/scramble/scramble.cpp $
  11  * $Revision$
  12  * $Date$
  13  * $Author$
  14  *
  15  * Module for file scrambler
  16  *
  17  * $Log$
  18  * Revision 1.3  2003/01/30 20:05:01  relnev
  19  * ported (Taylor Richards)
  20  *
  21  * Revision 1.2  2002/06/09 04:41:25  relnev
  22  * added copyright header
  23  *
  24  * Revision 1.1.1.1  2002/05/03 03:28:10  root
  25  * Initial import.
  26  *
  27  *
  28  * 3     3/25/99 11:26a Dave
  29  * Beefed up encryption scheme so that even someone viewing the
  30  * disassembly would have a hard time cracking it.
  31  *
  32  * 2     10/24/98 11:41p Dave
  33  *
  34  * 1     10/24/98 11:31p Dave
  35  *
  36  * 7     8/09/98 4:44p Lawrance
  37  * support alternate encryption scheme (doesn't pack chars into 7 bits)
  38  *
  39  * 6     4/14/98 4:14p Lawrance
  40  * fix bug with ships and weapons tbl preprocessing
  41  *
  42  * 5     4/14/98 1:39p Lawrance
  43  * Add command line switches to preprocess ship and weapon tables
  44  *
  45  * 4     3/31/98 1:14a Lawrance
  46  * Get .tbl and mission file encryption working.
  47  *
  48  * 3     3/30/98 5:57p Lawrance
  49  * add some comments
  50  *
  51  * 2     3/30/98 5:51p Lawrance
  52  * file encryption and decryption
  53  *
  54  * $NoKeywords: $
  55  *
  56 */
  57
  58 #include <stdlib.h>
  59 #include <stdio.h>
  60 #ifndef PLAT_UNIX
  61 #include <io.h>
  62 #else
  63 #include <sys/stat.h>
  64 #endif
  65 #include <string.h>
  66
  67 #define SDL_MAIN_HANDLED
  68
  69 #include "pstypes.h"
  70 #include "encrypt.h"
  71 #include "scramble.h"
  72
  73 #undef malloc
  74 #undef free
  75 #undef strdup
  76
  77 #ifndef PLAT_UNIX
  78 #define strncasecmp strnicmp
  79 #define strcasecmp stricmp
  80 #else
  81 int _filelength (int fd)
  82 {
  83         struct stat buf;
  84         if (fstat (fd, &buf) == -1)
  85                 return -1;
  86
  87         return buf.st_size;
  88 }
  89 #endif
  90
  91 #define MAX_LINE_LEN    512
  92
  93 //static int Use_8bit = 0;      // set to 1 to disable 7bit character packing
  94 static int Use_8bit = 1;
  95
  96
  97 // strip out any ships tbl data not used in demo (ie entries without @ preceding name)
  98 void scramble_read_ships_tbl(char **text, int *text_len, FILE *fp)
  99 {
 100         char    line[MAX_LINE_LEN+1];
 101         char    token_line[MAX_LINE_LEN+1];
 102         char    *dest;
 103         int     line_len, discard_line = 1, keep_all_lines = 0, post_discard = 0;
 104         char    seps[]   = " ,\t\n";
 105         char    *token;
 106
 107         *text_len = _filelength(fileno(fp));
 108         *text = (char*)malloc(*text_len+1);
 109
 110         dest = *text;
 111
 112         while ( fgets(line, MAX_LINE_LEN, fp) != NULL ) {
 113
 114                 line_len = strlen(line);
 115                 memcpy(token_line, line, line_len+1);
 116
 117                 if ( !keep_all_lines ) {
 118                         token = strtok( token_line, seps );
 119
 120                         if ( token ) {
 121                                 if ( !strncasecmp("#End", token, 4) ) {
 122                                         keep_all_lines = 1;
 123                                 } else if ( !strncasecmp("#Ship", token, 5) ) {
 124                                         discard_line = 0;
 125                                         post_discard = 1;
 126                                 } else if ( !strncasecmp("$Name:", token, 6) ) {
 127                                         token = strtok( NULL, seps );
 128                                         if ( token ) {
 129                                                 if ( token[0] == '@' ) {
 130                                                         discard_line = 0;
 131                                                 } else {
 132                                                         discard_line = 1;
 133                                                 }
 134                                         }
 135                                 }
 136                         }
 137                 }
 138
 139                 if ( !discard_line || keep_all_lines ) {
 140                         memcpy(dest, line, line_len);
 141                         dest += line_len;
 142                 }
 143
 144                 if ( post_discard ) {
 145                         discard_line = 1;
 146                         post_discard = 0;
 147                 }
 148         }
 149
 150         *text_len = dest - *text;
 151 }
 152
 153 // strip out any weapons tbl data not used in demo (ie entries without @ preceding name)
 154 void scramble_read_weapons_tbl(char **text, int *text_len, FILE *fp)
 155 {
 156         char    line[MAX_LINE_LEN+1];
 157         char    token_line[MAX_LINE_LEN+1];
 158         char    *dest;
 159         int     line_len, discard_line = 1, keep_all_lines = 0, post_discard = 0;
 160         char    seps[]   = " ,\t\n";
 161         char    *token = NULL;
 162
 163         *text_len = _filelength(fileno(fp));
 164         *text = (char*)malloc(*text_len+1);
 165
 166         dest = *text;
 167
 168         while ( fgets(line, MAX_LINE_LEN, fp) != NULL ) {
 169
 170                 line_len = strlen(line);
 171                 memcpy(token_line, line, line_len+1);
 172
 173                 if ( !keep_all_lines ) {
 174                         token = strtok( token_line, seps );
 175
 176                         if ( token ) {
 177                                 if ( !strncasecmp("#Countermeasures", token, 16) ) {
 178                                         keep_all_lines = 1;
 179                                 } else if ( !strncasecmp("#End", token, 4) || !strncasecmp("#Beam", token, 5) || !strncasecmp("#Primary", token, 8) || !strncasecmp("#Secondary", token, 10) ) {
 180                                         discard_line = 0;
 181                                         post_discard = 1;
 182                                 } else if ( !strncasecmp("$Name:", token, 6) ) {
 183                                         discard_line = 1;
 184                                         token = strtok( NULL, seps );
 185                                         if ( token ) {
 186                                                 if ( token[0] == '@' ) {
 187                                                         discard_line = 0;
 188                                                 }
 189                                         }
 190                                 }
 191                         }
 192                 }
 193
 194                 if ( (token[0] != ';') && (!discard_line || keep_all_lines) ) {
 195                         memcpy(dest, line, line_len);
 196                         dest += line_len;
 197                 }
 198
 199                 if ( post_discard ) {
 200                         discard_line = 1;
 201                         post_discard = 0;
 202                 }
 203         }
 204
 205         *text_len = dest - *text;
 206 }
 207
 208 void scramble_read_default(char **text, int *text_len, FILE *fp)
 209 {
 210         *text_len = _filelength(fileno(fp));
 211         *text = (char*)malloc(*text_len+1);
 212
 213         if ( !fread(*text, *text_len, 1, fp) ) {
 214                 free(*text);
 215                 *text = NULL;
 216                 *text_len = 0;
 217         }
 218 }
 219
 220 // scramble a file
 221 //
 222 // input:       src_filename    =>      filename of text to scramble
 223 //                              dest_filename   =>      optional, this is the filename scrambled data will get stored to
 224 void scramble_file(char *src_filename, char *dest_filename, int preprocess)
 225 {
 226         FILE    *fp;
 227         int     text_len, scramble_len;
 228         char    *text, *scramble_text;
 229
 230         fp = fopen(src_filename, "rb");
 231         if ( !fp ) {
 232                 return;
 233         }
 234
 235         // read in data, maybe preprocess
 236         switch(preprocess) {
 237         case PREPROCESS_SHIPS_TBL:
 238                 scramble_read_ships_tbl(&text, &text_len, fp);
 239                 break;
 240         case PREPROCESS_WEAPONS_TBL:
 241                 scramble_read_weapons_tbl(&text, &text_len, fp);
 242                 break;
 243         default:
 244                 // read in the raw data
 245                 scramble_read_default(&text, &text_len, fp);
 246                 break;
 247         }
 248
 249         fclose(fp);
 250
 251         if (text == NULL) {
 252                 return;
 253         }
 254
 255         // open up file for writing scrambled text
 256         if ( dest_filename ) {
 257                 fp = fopen(dest_filename, "wb");
 258         } else {
 259                 fp = fopen(src_filename, "wb");
 260         }
 261
 262         if ( !fp ) {
 263                 return;
 264         }
 265
 266         scramble_text = (char*)malloc(text_len+32);
 267
 268         encrypt(text, text_len, scramble_text, &scramble_len, Use_8bit);
 269
 270         // write out scrambled data
 271         fwrite( scramble_text, scramble_len, 1, fp );
 272
 273         free(text);
 274         free(scramble_text);
 275         fclose(fp);
 276 }
 277
 278 // unscramble a file
 279 //
 280 // input:       src_filename    =>      filename of scrambled text
 281 //                              dest_filename   =>      optional, this is the filename unscrambled text data will get stored to
 282 void unscramble_file(char *src_filename, char *dest_filename)
 283 {
 284         FILE    *fp;
 285         int     scramble_len, text_len;
 286         char    *text, *scramble_text;
 287
 288         fp = fopen(src_filename, "rb");
 289         if ( !fp ) {
 290                 return;
 291         }
 292
 293         // read in the scrambled data
 294         scramble_len = _filelength(fileno(fp));
 295         scramble_text = (char*)malloc(scramble_len+1);
 296
 297         if ( !fread(scramble_text, scramble_len, 1, fp) ) {
 298                 fclose(fp);
 299                 free(scramble_text);
 300                 return;
 301         }
 302
 303         fclose(fp);
 304
 305         // open up file for writing unscrambled text
 306         if ( dest_filename ) {
 307                 fp = fopen(dest_filename, "wb");
 308         } else {
 309                 fp = fopen(src_filename, "wb");
 310         }
 311         if ( !fp ) {
 312                 return;
 313         }
 314
 315         // assume original text no larger than double scrambled size
 316         text = (char*)malloc(scramble_len*2);
 317
 318         unencrypt(scramble_text, scramble_len, text, &text_len);
 319
 320         // write out unscrambled data
 321         fwrite( text, text_len, 1, fp );
 322
 323         free(text);
 324         free(scramble_text);
 325         fclose(fp);
 326 }
 327
 328 void print_instructions()
 329 {
 330         printf("Encrypt: scramble [-st] [-wt] <filename_in> [filename_out] \n");
 331         printf("Decrypt: scramble -u <filename_in> [filename_out] \n");
 332 }
 333
 334 int main(int argc, char *argv[])
 335 {
 336         switch (argc) {
 337         case 2:
 338                 encrypt_init();
 339                 scramble_file(argv[1]);
 340                 break;
 341         case 3:
 342                 encrypt_init();
 343                 if ( !strcasecmp("-u", argv[1]) ) {
 344                         unscramble_file(argv[2]);
 345                 } else if ( !strcasecmp("-st", argv[1]) ) {
 346                         scramble_file(argv[2], argv[2], PREPROCESS_SHIPS_TBL);
 347                 } else if ( !strcasecmp("-wt", argv[1]) ) {
 348                         scramble_file(argv[2], argv[2], PREPROCESS_WEAPONS_TBL);
 349                 } else {
 350                         scramble_file(argv[1], argv[2]);
 351                 }
 352                 break;
 353         case 4:
 354                 encrypt_init();
 355                 if ( !strcasecmp("-u", argv[1]) ) {
 356                         unscramble_file(argv[2], argv[3]);
 357                 } else if ( !strcasecmp("-st", argv[1]) ) {
 358                         scramble_file(argv[2], argv[3], PREPROCESS_SHIPS_TBL);
 359                 } else if ( !strcasecmp("-wt", argv[1]) ) {
 360                         scramble_file(argv[2], argv[3], PREPROCESS_WEAPONS_TBL);
 361                 } else {
 362                         print_instructions();
 363                 }
 364                 break;
 365         default:
 366                 print_instructions();
 367                 break;
 368         }
 369
 370         return 0;
 371 }
 372