adventure/save.c

   1 /*      $NetBSD: save.c,v 1.14 2014/03/22 22:04:40 dholland Exp $       */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * The game adventure was originally written in Fortran by Will Crowther
   8  * and Don Woods.  It was later translated to C and enhanced by Jim
   9  * Gillogly.  This code is derived from software contributed to Berkeley
  10  * by Jim Gillogly at The Rand Corporation.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #include <sys/cdefs.h>
  38 #ifndef lint
  39 #if 0
  40 static char sccsid[] = "@(#)save.c      8.1 (Berkeley) 5/31/93";
  41 #else
  42 __RCSID("$NetBSD: save.c,v 1.14 2014/03/22 22:04:40 dholland Exp $");
  43 #endif
  44 #endif                          /* not lint */
  45
  46 #include <sys/types.h>
  47 #include <sys/time.h>
  48 #include <stdbool.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <err.h>
  52 #include <assert.h>
  53
  54 #include "hdr.h"
  55 #include "extern.h"
  56
  57 struct savefile {
  58         FILE *f;
  59         const char *name;
  60         bool warned;
  61         size_t bintextpos;
  62         uint32_t key;
  63         struct crcstate crc;
  64         unsigned char pad[8];
  65         unsigned padpos;
  66 };
  67
  68 #define BINTEXT_WIDTH 60
  69 #define FORMAT_VERSION 2
  70 #define FORMAT_VERSION_NOSUM 1
  71 static const char header[] = "Adventure save file\n";
  72
  73 ////////////////////////////////////////////////////////////
  74 // base16 output encoding
  75
  76 /*
  77  * Map 16 plain values into 90 coded values and back.
  78  */
  79
  80 static const char coding[90] =
  81         "Db.GOyT]7a6zpF(c*5H9oK~0[WVAg&kR)ml,2^q-1Y3v+"
  82         "X/=JirZL$C>_N?:}B{dfnsxU<@MQ%8|P!4h`ESt;euwIj"
  83 ;
  84
  85 static int
  86 readletter(char letter, unsigned char *ret)
  87 {
  88         const char *s;
  89
  90         s = strchr(coding, letter);
  91         if (s == NULL) {
  92                 return 1;
  93         }
  94         *ret = (s - coding) % 16;
  95         return 0;
  96 }
  97
  98 static char
  99 writeletter(unsigned char nibble)
 100 {
 101         unsigned code;
 102
 103         assert(nibble < 16);
 104         do {
 105                 code = (16 * (random() % 6)) + nibble;
 106         } while (code >= 90);
 107         return coding[code];
 108 }
 109
 110 ////////////////////////////////////////////////////////////
 111 // savefile
 112
 113 /*
 114  * Open a savefile.
 115  */
 116 static struct savefile *
 117 savefile_open(const char *name, bool forwrite)
 118 {
 119         struct savefile *sf;
 120
 121         sf = malloc(sizeof(*sf));
 122         if (sf == NULL) {
 123                 return NULL;
 124         }
 125         sf->f = fopen(name, forwrite ? "w" : "r");
 126         if (sf->f == NULL) {
 127                 free(sf);
 128                 fprintf(stderr,
 129                     "Hmm.  The name \"%s\" appears to be magically blocked.\n",
 130                     name);
 131                 return NULL;
 132         }
 133         sf->name = name;
 134         sf->warned = false;
 135         sf->bintextpos = 0;
 136         sf->key = 0;
 137         crc_start(&sf->crc);
 138         memset(sf->pad, 0, sizeof(sf->pad));
 139         sf->padpos = 0;
 140         return sf;
 141 }
 142
 143 /*
 144  * Raw read.
 145  */
 146 static int
 147 savefile_rawread(struct savefile *sf, void *data, size_t len)
 148 {
 149         size_t result;
 150
 151         result = fread(data, 1, len, sf->f);
 152         if (result != len || ferror(sf->f)) {
 153                 fprintf(stderr, "Oops: error reading %s.\n", sf->name);
 154                 sf->warned = true;
 155                 return 1;
 156         }
 157         return 0;
 158 }
 159
 160 /*
 161  * Raw write.
 162  */
 163 static int
 164 savefile_rawwrite(struct savefile *sf, const void *data, size_t len)
 165 {
 166         size_t result;
 167
 168         result = fwrite(data, 1, len, sf->f);
 169         if (result != len || ferror(sf->f)) {
 170                 fprintf(stderr, "Oops: error writing %s.\n", sf->name);
 171                 sf->warned = true;
 172                 return 1;
 173         }
 174         return 0;
 175 }
 176
 177 /*
 178  * Close a savefile.
 179  */
 180 static int
 181 savefile_close(struct savefile *sf)
 182 {
 183         int ret;
 184
 185         if (sf->bintextpos > 0) {
 186                 savefile_rawwrite(sf, "\n", 1);
 187         }
 188
 189         ret = 0;
 190         if (fclose(sf->f)) {
 191                 if (!sf->warned) {
 192                         fprintf(stderr, "Oops: error on %s.\n", sf->name);
 193                 }
 194                 ret = 1;
 195         }
 196         free(sf);
 197         return ret;
 198 }
 199
 200 /*
 201  * Read encoded binary data, discarding any whitespace that appears.
 202  */
 203 static int
 204 savefile_bintextread(struct savefile *sf, void *data, size_t len)
 205 {
 206         size_t pos;
 207         unsigned char *udata;
 208         int ch;
 209
 210         udata = data;
 211         pos = 0;
 212         while (pos < len) {
 213                 ch = fgetc(sf->f);
 214                 if (ch == EOF || ferror(sf->f)) {
 215                         fprintf(stderr, "Oops: error reading %s.\n", sf->name);
 216                         sf->warned = true;
 217                         return 1;
 218                 }
 219                 if (ch == ' ' || ch == '\t' || ch == '\r' || ch == '\n') {
 220                         continue;
 221                 }
 222                 udata[pos++] = ch;
 223         }
 224         return 0;
 225 }
 226
 227 /*
 228  * Read binary data, decoding from text using readletter().
 229  */
 230 static int
 231 savefile_binread(struct savefile *sf, void *data, size_t len)
 232 {
 233         unsigned char buf[64];
 234         unsigned char *udata;
 235         unsigned char val1, val2;
 236         size_t pos, amt, i;
 237
 238         udata = data;
 239         pos = 0;
 240         while (pos < len) {
 241                 amt = len - pos;
 242                 if (amt > sizeof(buf) / 2) {
 243                         amt = sizeof(buf) / 2;
 244                 }
 245                 if (savefile_bintextread(sf, buf, amt*2)) {
 246                         return 1;
 247                 }
 248                 for (i=0; i<amt; i++) {
 249                         if (readletter(buf[i*2], &val1)) {
 250                                 return 1;
 251                         }
 252                         if (readletter(buf[i*2 + 1], &val2)) {
 253                                 return 1;
 254                         }
 255                         udata[pos++] = val1 * 16 + val2;
 256                 }
 257         }
 258         return 0;
 259 }
 260
 261 /*
 262  * Write encoded binary data, inserting newlines to get a neatly
 263  * formatted block.
 264  */
 265 static int
 266 savefile_bintextwrite(struct savefile *sf, const void *data, size_t len)
 267 {
 268         size_t pos, amt;
 269         const unsigned char *udata;
 270
 271         udata = data;
 272         pos = 0;
 273         while (pos < len) {
 274                 amt = BINTEXT_WIDTH - sf->bintextpos;
 275                 if (amt > len - pos) {
 276                         amt = len - pos;
 277                 }
 278                 if (savefile_rawwrite(sf, udata + pos, amt)) {
 279                         return 1;
 280                 }
 281                 pos += amt;
 282                 sf->bintextpos += amt;
 283                 if (sf->bintextpos >= BINTEXT_WIDTH) {
 284                         savefile_rawwrite(sf, "\n", 1);
 285                         sf->bintextpos = 0;
 286                 }
 287         }
 288         return 0;
 289 }
 290
 291 /*
 292  * Write binary data, encoding as text using writeletter().
 293  */
 294 static int
 295 savefile_binwrite(struct savefile *sf, const void *data, size_t len)
 296 {
 297         unsigned char buf[64];
 298         const unsigned char *udata;
 299         size_t pos, bpos;
 300         unsigned char byte;
 301
 302         udata = data;
 303         pos = 0;
 304         bpos = 0;
 305         while (pos < len) {
 306                 byte = udata[pos++];
 307                 buf[bpos++] = writeletter(byte >> 4);
 308                 buf[bpos++] = writeletter(byte & 0xf);
 309                 if (bpos >= sizeof(buf)) {
 310                         if (savefile_bintextwrite(sf, buf, bpos)) {
 311                                 return 1;
 312                         }
 313                         bpos = 0;
 314                 }
 315         }
 316         if (savefile_bintextwrite(sf, buf, bpos)) {
 317                 return 1;
 318         }
 319         return 0;
 320 }
 321
 322 /*
 323  * Lightweight "encryption" for save files. This is not meant to
 324  * be secure and wouldn't be even if we didn't write the decrypt
 325  * key to the beginning of the save file; it's just meant to be
 326  * enough to discourage casual cheating.
 327  */
 328
 329 /*
 330  * Make cheesy hash of buf[0..buflen]. Note: buf and outhash may overlap.
 331  */
 332 static void
 333 hash(const void *data, size_t datalen, unsigned char *out, size_t outlen)
 334 {
 335         const unsigned char *udata;
 336         size_t i;
 337         uint64_t val;
 338         const unsigned char *uval;
 339         size_t valpos;
 340
 341         udata = data;
 342         val = 0;
 343         for (i=0; i<datalen; i++) {
 344                 val = val ^ 0xbadc0ffee;
 345                 val = (val << 4) | (val >> 60);
 346                 val += udata[i] ^ 0xbeefU;
 347         }
 348
 349         uval = (unsigned char *)&val;
 350         valpos = 0;
 351         for (i=0; i<outlen; i++) {
 352                 out[i] = uval[valpos++];
 353                 if (valpos >= sizeof(val)) {
 354                         valpos = 0;
 355                 }
 356         }
 357 }
 358
 359 /*
 360  * Set the "encryption" key.
 361  */
 362 static void
 363 savefile_key(struct savefile *sf, uint32_t key)
 364 {
 365         sf->key = 0;
 366         crc_start(&sf->crc);
 367         hash(&sf->key, sizeof(sf->key), sf->pad, sizeof(sf->pad));
 368         sf->padpos = 0;
 369 }
 370
 371 /*
 372  * Get an "encryption" pad byte. This forms a stream "cipher" that we
 373  * xor with the plaintext save data.
 374  */
 375 static unsigned char
 376 savefile_getpad(struct savefile *sf)
 377 {
 378         unsigned char ret;
 379
 380         ret = sf->pad[sf->padpos++];
 381         if (sf->padpos >= sizeof(sf->pad)) {
 382                 hash(sf->pad, sizeof(sf->pad), sf->pad, sizeof(sf->pad));
 383                 sf->padpos = 0;
 384         }
 385         return ret;
 386 }
 387
 388 /*
 389  * Read "encrypted" data.
 390  */
 391 static int
 392 savefile_cread(struct savefile *sf, void *data, size_t len)
 393 {
 394         char buf[64];
 395         unsigned char *udata;
 396         size_t pos, amt, i;
 397         unsigned char ch;
 398
 399         udata = data;
 400         pos = 0;
 401         while (pos < len) {
 402                 amt = len - pos;
 403                 if (amt > sizeof(buf)) {
 404                         amt = sizeof(buf);
 405                 }
 406                 if (savefile_binread(sf, buf, amt)) {
 407                         return 1;
 408                 }
 409                 for (i=0; i<amt; i++) {
 410                         ch = buf[i];
 411                         ch ^= savefile_getpad(sf);
 412                         udata[pos + i] = ch;
 413                 }
 414                 pos += amt;
 415         }
 416         crc_add(&sf->crc, data, len);
 417         return 0;
 418 }
 419
 420 /*
 421  * Write "encrypted" data.
 422  */
 423 static int
 424 savefile_cwrite(struct savefile *sf, const void *data, size_t len)
 425 {
 426         char buf[64];
 427         const unsigned char *udata;
 428         size_t pos, amt, i;
 429         unsigned char ch;
 430
 431         udata = data;
 432         pos = 0;
 433         while (pos < len) {
 434                 amt = len - pos;
 435                 if (amt > sizeof(buf)) {
 436                         amt = sizeof(buf);
 437                 }
 438                 for (i=0; i<amt; i++) {
 439                         ch = udata[pos + i];
 440                         ch ^= savefile_getpad(sf);
 441                         buf[i] = ch;
 442                 }
 443                 if (savefile_binwrite(sf, buf, amt)) {
 444                         return 1;
 445                 }
 446                 pos += amt;
 447         }
 448         crc_add(&sf->crc, data, len);
 449         return 0;
 450 }
 451
 452 ////////////////////////////////////////////////////////////
 453 // compat for old save files
 454
 455 struct compat_saveinfo {
 456         void   *address;
 457         size_t  width;
 458 };
 459
 460 static const struct compat_saveinfo compat_savearray[] =
 461 {
 462         {&abbnum, sizeof(abbnum)},
 463         {&attack, sizeof(attack)},
 464         {&blklin, sizeof(blklin)},
 465         {&bonus, sizeof(bonus)},
 466         {&chloc, sizeof(chloc)},
 467         {&chloc2, sizeof(chloc2)},
 468         {&clock1, sizeof(clock1)},
 469         {&clock2, sizeof(clock2)},
 470         {&closed, sizeof(closed)},
 471         {&isclosing, sizeof(isclosing)},
 472         {&daltloc, sizeof(daltloc)},
 473         {&demo, sizeof(demo)},
 474         {&detail, sizeof(detail)},
 475         {&dflag, sizeof(dflag)},
 476         {&dkill, sizeof(dkill)},
 477         {&dtotal, sizeof(dtotal)},
 478         {&foobar, sizeof(foobar)},
 479         {&gaveup, sizeof(gaveup)},
 480         {&holding, sizeof(holding)},
 481         {&iwest, sizeof(iwest)},
 482         {&k, sizeof(k)},
 483         {&k2, sizeof(k2)},
 484         {&knfloc, sizeof(knfloc)},
 485         {&kq, sizeof(kq)},
 486         {&latency, sizeof(latency)},
 487         {&limit, sizeof(limit)},
 488         {&lmwarn, sizeof(lmwarn)},
 489         {&loc, sizeof(loc)},
 490         {&maxdie, sizeof(maxdie)},
 491         {&maxscore, sizeof(maxscore)},
 492         {&newloc, sizeof(newloc)},
 493         {&numdie, sizeof(numdie)},
 494         {&obj, sizeof(obj)},
 495         {&oldloc2, sizeof(oldloc2)},
 496         {&oldloc, sizeof(oldloc)},
 497         {&panic, sizeof(panic)},
 498         {&saveday, sizeof(saveday)},
 499         {&savet, sizeof(savet)},
 500         {&scoring, sizeof(scoring)},
 501         {&spk, sizeof(spk)},
 502         {&stick, sizeof(stick)},
 503         {&tally, sizeof(tally)},
 504         {&tally2, sizeof(tally2)},
 505         {&tkk, sizeof(tkk)},
 506         {&turns, sizeof(turns)},
 507         {&verb, sizeof(verb)},
 508         {&wd1, sizeof(wd1)},
 509         {&wd2, sizeof(wd2)},
 510         {&wasdark, sizeof(wasdark)},
 511         {&yea, sizeof(yea)},
 512         {atloc, sizeof(atloc)},
 513         {dloc, sizeof(dloc)},
 514         {dseen, sizeof(dseen)},
 515         {fixed, sizeof(fixed)},
 516         {hinted, sizeof(hinted)},
 517         {links, sizeof(links)},
 518         {odloc, sizeof(odloc)},
 519         {place, sizeof(place)},
 520         {prop, sizeof(prop)},
 521         {tk, sizeof(tk)},
 522
 523         {NULL, 0}
 524 };
 525
 526 static int
 527 compat_restore(const char *infile)
 528 {
 529         FILE   *in;
 530         const struct compat_saveinfo *p;
 531         char   *s;
 532         long    sum, cksum = 0;
 533         size_t  i;
 534         struct crcstate crc;
 535
 536         if ((in = fopen(infile, "rb")) == NULL) {
 537                 fprintf(stderr,
 538                     "Hmm.  The file \"%s\" appears to be magically blocked.\n",
 539                     infile);
 540                 return 1;
 541         }
 542         fread(&sum, sizeof(sum), 1, in);        /* Get the seed */
 543         srandom((int) sum);
 544         for (p = compat_savearray; p->address != NULL; p++) {
 545                 fread(p->address, p->width, 1, in);
 546                 for (s = p->address, i = 0; i < p->width; i++, s++)
 547                         *s = (*s ^ random()) & 0xFF;    /* Lightly decrypt */
 548         }
 549         fclose(in);
 550
 551         crc_start(&crc);                /* See if she cheated */
 552         for (p = compat_savearray; p->address != NULL; p++)
 553                 crc_add(&crc, p->address, p->width);
 554         cksum = crc_get(&crc);
 555         if (sum != cksum)       /* Tsk tsk */
 556                 return 2;       /* Altered the file */
 557         /* We successfully restored, so this really was a save file */
 558
 559         /*
 560          * The above code loads these from disk even though they're
 561          * pointers. Null them out and hope we don't crash on them
 562          * later; that's better than having them be garbage.
 563          */
 564         tkk = NULL;
 565         wd1 = NULL;
 566         wd2 = NULL;
 567
 568         return 0;
 569 }
 570
 571 ////////////////////////////////////////////////////////////
 572 // save + restore
 573
 574 static int *const save_ints[] = {
 575         &abbnum,
 576         &attack,
 577         &blklin,
 578         &bonus,
 579         &chloc,
 580         &chloc2,
 581         &clock1,
 582         &clock2,
 583         &closed,
 584         &isclosing,
 585         &daltloc,
 586         &demo,
 587         &detail,
 588         &dflag,
 589         &dkill,
 590         &dtotal,
 591         &foobar,
 592         &gaveup,
 593         &holding,
 594         &iwest,
 595         &k,
 596         &k2,
 597         &knfloc,
 598         &kq,
 599         &latency,
 600         &limit,
 601         &lmwarn,
 602         &loc,
 603         &maxdie,
 604         &maxscore,
 605         &newloc,
 606         &numdie,
 607         &obj,
 608         &oldloc2,
 609         &oldloc,
 610         &panic,
 611         &saveday,
 612         &savet,
 613         &scoring,
 614         &spk,
 615         &stick,
 616         &tally,
 617         &tally2,
 618         &turns,
 619         &verb,
 620         &wasdark,
 621         &yea,
 622 };
 623 static const unsigned num_save_ints = __arraycount(save_ints);
 624
 625 #define INTARRAY(sym) { sym, __arraycount(sym) }
 626
 627 static const struct {
 628         int *ptr;
 629         unsigned num;
 630 } save_intarrays[] = {
 631         INTARRAY(atloc),
 632         INTARRAY(dseen),
 633         INTARRAY(dloc),
 634         INTARRAY(odloc),
 635         INTARRAY(fixed),
 636         INTARRAY(hinted),
 637         INTARRAY(links),
 638         INTARRAY(place),
 639         INTARRAY(prop),
 640         INTARRAY(tk),
 641 };
 642 static const unsigned num_save_intarrays = __arraycount(save_intarrays);
 643
 644 #undef INTARRAY
 645
 646 #if 0
 647 static const struct {
 648         void *ptr;
 649         size_t len;
 650 } save_blobs[] = {
 651         { &wd1, sizeof(wd1) },
 652         { &wd2, sizeof(wd2) },
 653         { &tkk, sizeof(tkk) },
 654 };
 655 static const unsigned num_save_blobs = __arraycount(save_blobs);
 656 #endif
 657
 658 /*
 659  * Write out a save file. Returns nonzero on error.
 660  */
 661 int
 662 save(const char *outfile)
 663 {
 664         struct savefile *sf;
 665         struct timespec now;
 666         uint32_t key, writeable_key;
 667         uint32_t version;
 668         unsigned i, j, n;
 669         uint32_t val, sum;
 670
 671         sf = savefile_open(outfile, true);
 672         if (sf == NULL) {
 673                 return 1;
 674         }
 675
 676         if (savefile_rawwrite(sf, header, strlen(header))) {
 677                 savefile_close(sf);
 678                 return 1;
 679         }
 680
 681         version = htonl(FORMAT_VERSION);
 682         if (savefile_binwrite(sf, &version, sizeof(version))) {
 683                 savefile_close(sf);
 684                 return 1;
 685         }
 686
 687         clock_gettime(CLOCK_REALTIME, &now);
 688         key = (uint32_t)(now.tv_sec & 0xffffffff) ^ (uint32_t)(now.tv_nsec);
 689
 690         writeable_key = htonl(key);
 691         if (savefile_binwrite(sf, &writeable_key, sizeof(writeable_key))) {
 692                 savefile_close(sf);
 693                 return 1;
 694         }
 695
 696         /* other parts of the code may depend on us doing this here */
 697         srandom(key);
 698
 699         savefile_key(sf, key);
 700
 701         /*
 702          * Integers
 703          */
 704         for (i=0; i<num_save_ints; i++) {
 705                 val = *(save_ints[i]);
 706                 val = htonl(val);
 707                 if (savefile_cwrite(sf, &val, sizeof(val))) {
 708                         savefile_close(sf);
 709                         return 1;
 710                 }
 711         }
 712
 713         /*
 714          * Arrays of integers
 715          */
 716         for (i=0; i<num_save_intarrays; i++) {
 717                 n = save_intarrays[i].num;
 718                 for (j=0; j<n; j++) {
 719                         val = save_intarrays[i].ptr[j];
 720                         val = htonl(val);
 721                         if (savefile_cwrite(sf, &val, sizeof(val))) {
 722                                 savefile_close(sf);
 723                                 return 1;
 724                         }
 725                 }
 726         }
 727
 728 #if 0
 729         /*
 730          * Blobs
 731          */
 732         for (i=0; i<num_save_blobs; i++) {
 733                 if (savefile_cwrite(sf, save_blobs[i].ptr, save_blobs[i].len)) {
 734                         savefile_close(sf);
 735                         return 1;
 736                 }
 737         }
 738 #endif
 739
 740         sum = htonl(crc_get(&sf->crc));
 741         if (savefile_binwrite(sf, &sum, sizeof(&sum))) {
 742                 savefile_close(sf);
 743                 return 1;
 744         }
 745         savefile_close(sf);
 746         return 0;
 747 }
 748
 749 /*
 750  * Read in a save file. Returns nonzero on error.
 751  */
 752 int
 753 restore(const char *infile)
 754 {
 755         struct savefile *sf;
 756         char buf[sizeof(header)];
 757         size_t headersize = strlen(header);
 758         uint32_t version, key, sum;
 759         unsigned i, j, n;
 760         uint32_t val;
 761         bool skipsum = false;
 762
 763         sf = savefile_open(infile, false);
 764         if (sf == NULL) {
 765                 return 1;
 766         }
 767
 768         if (savefile_rawread(sf, buf, headersize)) {
 769                 savefile_close(sf);
 770                 return 1;
 771         }
 772         buf[headersize] = 0;
 773         if (strcmp(buf, header) != 0) {
 774                 savefile_close(sf);
 775                 fprintf(stderr, "Oh dear, that isn't one of my save files.\n");
 776                 fprintf(stderr,
 777                     "Trying the Olde Waye; this myte notte Worke.\n");
 778                 return compat_restore(infile);
 779         }
 780
 781         if (savefile_binread(sf, &version, sizeof(version))) {
 782                 savefile_close(sf);
 783                 return 1;
 784         }
 785         version = ntohl(version);
 786         switch (version) {
 787             case FORMAT_VERSION:
 788                 break;
 789             case FORMAT_VERSION_NOSUM:
 790                 skipsum = true;
 791                 break;
 792             default:
 793                 savefile_close(sf);
 794                 fprintf(stderr,
 795                     "Oh dear, that file must be from the future. I don't know"
 796                     " how to read it!\n");
 797                 return 1;
 798         }
 799
 800         if (savefile_binread(sf, &key, sizeof(key))) {
 801                 savefile_close(sf);
 802                 return 1;
 803         }
 804         key = ntohl(key);
 805         savefile_key(sf, key);
 806
 807         /* other parts of the code may depend on us doing this here */
 808         srandom(key);
 809
 810         /*
 811          * Integers
 812          */
 813         for (i=0; i<num_save_ints; i++) {
 814                 if (savefile_cread(sf, &val, sizeof(val))) {
 815                         savefile_close(sf);
 816                         return 1;
 817                 }
 818                 val = ntohl(val);
 819                 *(save_ints[i]) = val;
 820         }
 821
 822         /*
 823          * Arrays of integers
 824          */
 825         for (i=0; i<num_save_intarrays; i++) {
 826                 n = save_intarrays[i].num;
 827                 for (j=0; j<n; j++) {
 828                         if (savefile_cread(sf, &val, sizeof(val))) {
 829                                 savefile_close(sf);
 830                                 return 1;
 831                         }
 832                         val = ntohl(val);
 833                         save_intarrays[i].ptr[j] = val;
 834                 }
 835         }
 836
 837 #if 0
 838         /*
 839          * Blobs
 840          */
 841         for (i=0; i<num_save_blobs; i++) {
 842                 if (savefile_cread(sf, save_blobs[i].ptr, save_blobs[i].len)) {
 843                         savefile_close(sf);
 844                         return 1;
 845                 }
 846         }
 847 #endif
 848
 849         if (savefile_binread(sf, &sum, sizeof(&sum))) {
 850                 savefile_close(sf);
 851                 return 1;
 852         }
 853         sum = ntohl(sum);
 854         /* See if she cheated */
 855         if (!skipsum && sum != crc_get(&sf->crc)) {
 856                 /* Tsk tsk, altered the file */
 857                 savefile_close(sf);
 858                 return 2;
 859         }
 860         savefile_close(sf);
 861
 862         /* Load theoretically invalidates these */
 863         tkk = NULL;
 864         wd1 = NULL;
 865         wd2 = NULL;
 866
 867         return 0;
 868 }