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 #include "pstypes.h"
  68 #include "encrypt.h"
  69 #include "scramble.h"
  70
  71 #undef malloc
  72 #undef free
  73 #undef strdup
  74
  75 #ifndef PLAT_UNIX
  76 #define strncasecmp strnicmp
  77 #define strcasecmp stricmp
  78 #else
  79 int _filelength (int fd)
  80 {
  81         struct stat buf;
  82         if (fstat (fd, &buf) == -1)
  83                 return -1;
  84
  85         return buf.st_size;
  86 }
  87 #endif
  88
  89 #define MAX_LINE_LEN    512
  90
  91 //static int Use_8bit = 0;      // set to 1 to disable 7bit character packing
  92 static int Use_8bit = 1;
  93
  94
  95 // strip out any ships tbl data not used in demo (ie entries without @ preceding name)
  96 void scramble_read_ships_tbl(char **text, int *text_len, FILE *fp)
  97 {
  98         char    line[MAX_LINE_LEN+1];
  99         char    token_line[MAX_LINE_LEN+1];
 100         char    *dest;
 101         int     line_len, discard_line = 1, keep_all_lines = 0, post_discard = 0;
 102         char    seps[]   = " ,\t\n";
 103         char    *token;
 104
 105         *text_len = _filelength(fileno(fp));
 106         *text = (char*)malloc(*text_len+1);
 107
 108         dest = *text;
 109
 110         while ( fgets(line, MAX_LINE_LEN, fp) != NULL ) {
 111
 112                 line_len = strlen(line);
 113                 memcpy(token_line, line, line_len+1);
 114
 115                 if ( !keep_all_lines ) {
 116                         token = strtok( token_line, seps );
 117
 118                         if ( token ) {
 119                                 if ( !strncasecmp("#End", token, 4) ) {
 120                                         keep_all_lines = 1;
 121                                 } else if ( !strncasecmp("#Ship", token, 5) ) {
 122                                         discard_line = 0;
 123                                         post_discard = 1;
 124                                 } else if ( !strncasecmp("$Name:", token, 6) ) {
 125                                         token = strtok( NULL, seps );
 126                                         if ( token ) {
 127                                                 if ( token[0] == '@' ) {
 128                                                         discard_line = 0;
 129                                                 } else {
 130                                                         discard_line = 1;
 131                                                 }
 132                                         }
 133                                 }
 134                         }
 135                 }
 136
 137                 if ( !discard_line || keep_all_lines ) {
 138                         memcpy(dest, line, line_len);
 139                         dest += line_len;
 140                 }
 141
 142                 if ( post_discard ) {
 143                         discard_line = 1;
 144                         post_discard = 0;
 145                 }
 146         }
 147
 148         *text_len = dest - *text;
 149 }
 150
 151 // strip out any weapons tbl data not used in demo (ie entries without @ preceding name)
 152 void scramble_read_weapons_tbl(char **text, int *text_len, FILE *fp)
 153 {
 154         char    line[MAX_LINE_LEN+1];
 155         char    token_line[MAX_LINE_LEN+1];
 156         char    *dest;
 157         int     line_len, discard_line = 1, keep_all_lines = 0, post_discard = 0;
 158         char    seps[]   = " ,\t\n";
 159         char    *token = NULL;
 160
 161         *text_len = _filelength(fileno(fp));
 162         *text = (char*)malloc(*text_len+1);
 163
 164         dest = *text;
 165
 166         while ( fgets(line, MAX_LINE_LEN, fp) != NULL ) {
 167
 168                 line_len = strlen(line);
 169                 memcpy(token_line, line, line_len+1);
 170
 171                 if ( !keep_all_lines ) {
 172                         token = strtok( token_line, seps );
 173
 174                         if ( token ) {
 175                                 if ( !strncasecmp("#Countermeasures", token, 16) ) {
 176                                         keep_all_lines = 1;
 177                                 } else if ( !strncasecmp("#End", token, 4) || !strncasecmp("#Beam", token, 5) || !strncasecmp("#Primary", token, 8) || !strncasecmp("#Secondary", token, 10) ) {
 178                                         discard_line = 0;
 179                                         post_discard = 1;
 180                                 } else if ( !strncasecmp("$Name:", token, 6) ) {
 181                                         discard_line = 1;
 182                                         token = strtok( NULL, seps );
 183                                         if ( token ) {
 184                                                 if ( token[0] == '@' ) {
 185                                                         discard_line = 0;
 186                                                 }
 187                                         }
 188                                 }
 189                         }
 190                 }
 191
 192                 if ( (token[0] != ';') && (!discard_line || keep_all_lines) ) {
 193                         memcpy(dest, line, line_len);
 194                         dest += line_len;
 195                 }
 196
 197                 if ( post_discard ) {
 198                         discard_line = 1;
 199                         post_discard = 0;
 200                 }
 201         }
 202
 203         *text_len = dest - *text;
 204 }
 205
 206 void scramble_read_default(char **text, int *text_len, FILE *fp)
 207 {
 208         *text_len = _filelength(fileno(fp));
 209         *text = (char*)malloc(*text_len+1);
 210         fread( *text, *text_len, 1, fp );
 211 }
 212
 213 // scramble a file
 214 //
 215 // input:       src_filename    =>      filename of text to scramble
 216 //                              dest_filename   =>      optional, this is the filename scrambled data will get stored to
 217 void scramble_file(char *src_filename, char *dest_filename, int preprocess)
 218 {
 219         FILE    *fp;
 220         int     text_len, scramble_len;
 221         char    *text, *scramble_text;
 222
 223         fp = fopen(src_filename, "rb");
 224         if ( !fp ) {
 225                 return;
 226         }
 227
 228         // read in data, maybe preprocess
 229         switch(preprocess) {
 230         case PREPROCESS_SHIPS_TBL:
 231                 scramble_read_ships_tbl(&text, &text_len, fp);
 232                 break;
 233         case PREPROCESS_WEAPONS_TBL:
 234                 scramble_read_weapons_tbl(&text, &text_len, fp);
 235                 break;
 236         default:
 237                 // read in the raw data
 238                 scramble_read_default(&text, &text_len, fp);
 239                 break;
 240         }
 241
 242         fclose(fp);
 243
 244         // open up file for writing scrambled text
 245         if ( dest_filename ) {
 246                 fp = fopen(dest_filename, "wb");
 247         } else {
 248                 fp = fopen(src_filename, "wb");
 249         }
 250
 251         if ( !fp ) {
 252                 return;
 253         }
 254
 255         scramble_text = (char*)malloc(text_len+32);
 256
 257         encrypt(text, text_len, scramble_text, &scramble_len, Use_8bit);
 258
 259         // write out scrambled data
 260         fwrite( scramble_text, scramble_len, 1, fp );
 261
 262         free(text);
 263         free(scramble_text);
 264         fclose(fp);
 265 }
 266
 267 // unscramble a file
 268 //
 269 // input:       src_filename    =>      filename of scrambled text
 270 //                              dest_filename   =>      optional, this is the filename unscrambled text data will get stored to
 271 void unscramble_file(char *src_filename, char *dest_filename)
 272 {
 273         FILE    *fp;
 274         int     scramble_len, text_len;
 275         char    *text, *scramble_text;
 276
 277         fp = fopen(src_filename, "rb");
 278         if ( !fp ) {
 279                 return;
 280         }
 281
 282         // read in the scrambled data
 283         scramble_len = _filelength(fileno(fp));
 284         scramble_text = (char*)malloc(scramble_len+1);
 285         fread( scramble_text, scramble_len, 1, fp );
 286         fclose(fp);
 287
 288         // open up file for writing unscrambled text
 289         if ( dest_filename ) {
 290                 fp = fopen(dest_filename, "wb");
 291         } else {
 292                 fp = fopen(src_filename, "wb");
 293         }
 294         if ( !fp ) {
 295                 return;
 296         }
 297
 298         // assume original text no larger than double scrambled size
 299         text = (char*)malloc(scramble_len*2);
 300
 301         unencrypt(scramble_text, scramble_len, text, &text_len);
 302
 303         // write out unscrambled data
 304         fwrite( text, text_len, 1, fp );
 305
 306         free(text);
 307         free(scramble_text);
 308         fclose(fp);
 309 }
 310
 311 void print_instructions()
 312 {
 313         printf("Encrypt: scramble [-st] [-wt] <filename_in> [filename_out] \n");
 314         printf("Decrypt: scramble -u <filename_in> [filename_out] \n");
 315 }
 316
 317 int main(int argc, char *argv[])
 318 {
 319         switch (argc) {
 320         case 2:
 321                 encrypt_init();
 322                 scramble_file(argv[1]);
 323                 break;
 324         case 3:
 325                 encrypt_init();
 326                 if ( !strcasecmp("-u", argv[1]) ) {
 327                         unscramble_file(argv[2]);
 328                 } else if ( !strcasecmp("-st", argv[1]) ) {
 329                         scramble_file(argv[2], argv[2], PREPROCESS_SHIPS_TBL);
 330                 } else if ( !strcasecmp("-wt", argv[1]) ) {
 331                         scramble_file(argv[2], argv[2], PREPROCESS_WEAPONS_TBL);
 332                 } else {
 333                         scramble_file(argv[1], argv[2]);
 334                 }
 335                 break;
 336         case 4:
 337                 encrypt_init();
 338                 if ( !strcasecmp("-u", argv[1]) ) {
 339                         unscramble_file(argv[2], argv[3]);
 340                 } else if ( !strcasecmp("-st", argv[1]) ) {
 341                         scramble_file(argv[2], argv[3], PREPROCESS_SHIPS_TBL);
 342                 } else if ( !strcasecmp("-wt", argv[1]) ) {
 343                         scramble_file(argv[2], argv[3], PREPROCESS_WEAPONS_TBL);
 344                 } else {
 345                         print_instructions();
 346                 }
 347                 break;
 348         default:
 349                 print_instructions();
 350                 break;
 351         }
 352
 353         return 0;
 354 }
 355