zip.c

   1 /*
   2 zip
   3 read from a zip file
   4
   5 Copyright (C) 2009 Evan Rinehart
   6
   7 This software comes with no warranty.
   8 1. This software can be used for any purpose, good or evil.
   9 2. Modifications must retain this license, at least in spirit.
  10 */
  11
  12 #include <stdio.h>
  13 #include <string.h>
  14 #include <stdlib.h>
  15
  16 #include <zlib.h>
  17
  18 #include <zip.h>
  19
  20 #define BUF_SIZE 1024
  21 #define TABLE_SIZE 128
  22 #define EBUF_SIZE 256
  23
  24 struct record {
  25         char* filename;
  26         unsigned offset;
  27         unsigned clen;
  28         unsigned ulen;
  29         unsigned method;
  30         struct record* next;
  31         struct record* contents;
  32 };
  33
  34 struct zip_archive {
  35         int (*read)(void* userdata, byte buf[], int count);
  36         int (*seek)(void* userdata, int offset, int whence);
  37         void (*close)(void* userdata);
  38         void* userdata;
  39
  40         struct record* table[TABLE_SIZE];
  41         int ptr;
  42 };
  43
  44 struct zip_file {
  45         zip_archive* arc;
  46         int cptr, clen;
  47         int uptr, ulen;
  48         int offset;
  49         byte inbuf[BUF_SIZE];
  50         int eof;
  51         z_stream strm;
  52 };
  53
  54 struct zip_dir {
  55         struct record* ptr;
  56 };
  57
  58
  59 static char errbuf[EBUF_SIZE] = "";
  60
  61
  62 /* internal routines */
  63
  64 static void set_error(char* msg){
  65         strncpy(errbuf, msg, EBUF_SIZE);
  66         errbuf[EBUF_SIZE-1] = '\0';
  67 }
  68
  69 static void out_of_memory(){
  70         set_error("OUT OF MEMORY");
  71 }
  72
  73 /* http://www.cse.yorku.ca/~oz/hash.html */
  74 static unsigned long hash(char* str){
  75         unsigned char* ptr = (unsigned char*)str;
  76         unsigned long hash = 5381;
  77         int c;
  78         while((c = *ptr++))
  79                 hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
  80         return hash;
  81 }
  82
  83
  84 static struct record* make_record(char* filename, int ulen, int clen, int offset, int method){
  85         struct record* r = malloc(sizeof(struct record));
  86         if(r == NULL){
  87                 return NULL;
  88         }
  89         r->filename = strdup(filename);
  90         r->clen = clen;
  91         r->ulen = ulen;
  92         r->offset = offset;
  93         r->method = method;
  94         r->next = NULL;
  95         r->contents = NULL;
  96         return r;
  97 }
  98
  99 static struct record* copy_record(struct record* rec){
 100         return make_record(rec->filename, rec->ulen, rec->clen, rec->offset, rec->method);
 101 }
 102
 103 static struct record* get_record(zip_archive* arc, char* filename){
 104         int i = hash(filename) % TABLE_SIZE;
 105         struct record* ptr = arc->table[i];
 106         while(ptr){
 107                 if(strcmp(filename, ptr->filename) == 0){
 108                         return ptr;
 109                 }
 110                 ptr = ptr->next;
 111         }
 112         return NULL;
 113 }
 114
 115 static void hash_insert(zip_archive* arc, struct record* rec){
 116         int i = hash(rec->filename) % TABLE_SIZE;
 117         struct record* ptr = arc->table[i];
 118
 119         if(get_record(arc, rec->filename)){
 120                 fprintf(stderr, "zip: can't insert %s twice\n", rec->filename);
 121                 return;
 122         }
 123
 124         if(ptr == NULL){
 125                 arc->table[i] = rec;
 126                 return;
 127         }
 128
 129         rec->next = ptr;
 130         arc->table[i] = rec;
 131 }
 132
 133 static char* baseof(char* path){
 134         if(strlen(path) < 2) return NULL;
 135         int ptr = strlen(path) - 2;
 136         while(ptr > 0 && path[ptr] != '/') ptr--;
 137         if(ptr == 0) return NULL;
 138         char* result = malloc(ptr+5);
 139         memcpy(result, path, ptr+1);
 140         result[ptr+1] = '\0';
 141         return result;
 142 }
 143
 144 static void contents_insert(struct record* item, struct record* dir){
 145         item->next = dir->contents;
 146         dir->contents = item;
 147 }
 148 /*
 149 static void print_hash(zip_archive* arc){
 150         int i;
 151         struct record* rec;
 152         for(i=0; i<TABLE_SIZE; i++){
 153                 printf("table[%d]: ",i);
 154                 rec = arc->table[i];
 155                 while(rec){
 156                         printf("%p ", rec);
 157                         rec = rec->next;
 158                 }
 159                 printf("\n");
 160         }
 161 }
 162
 163 static void print_zipfile(zip_file* f){
 164         printf("(+0x%x, %u/%uB, cptr +0x%x, uptr %u)\n",
 165         f->offset, f->clen, f->ulen, f->cptr, f->uptr);
 166 }
 167
 168 static void print_record(struct record* rec){
 169         printf("(%s, %uB, %uB, +0x%x, method %u)\n", rec->filename, rec->clen, rec->ulen, rec->offset, rec->method);
 170 }
 171 */
 172 static char* method_str(unsigned method){
 173         switch(method){
 174                 case 0: return "uncompressed";
 175                 case 1: return "shrink";
 176                 case 2:
 177                 case 3:
 178                 case 4:
 179                 case 5: return "reduce";
 180                 case 6: return "implode";
 181                 case 8: return "deflate";
 182                 case 9: return "deflate64";
 183                 case 10: return "IBM TERSE (old)";
 184                 case 12: return "bzip2";
 185                 case 14: return "lzma";
 186                 case 18: return "IBM TERSE (new)";
 187                 case 19: return "IBM LZ77 z";
 188                 case 97: return "WavPack";
 189                 case 98: return "PPMd";
 190                 default: return "unknown";
 191         }
 192 }
 193
 194 static void unrecognized_method(unsigned method){
 195         char buf[64];
 196         snprintf(buf, 64, "unrecognized compression method '%s'", method_str(method));
 197         buf[63] = '\0';
 198         set_error(buf);
 199 }
 200
 201 static void set_record(zip_archive* arc, char* filename, int ulen, int clen, int offset, int method){
 202         struct record* rec;
 203         struct record* dir;
 204         char* dirname;
 205         if(get_record(arc, filename)) return;
 206         rec = make_record(filename, ulen, clen, offset, method);
 207         hash_insert(arc, rec);
 208         dirname = baseof(filename);
 209         if(dirname == NULL) return;
 210         if(get_record(arc, dirname) == NULL)
 211                 set_record(arc, dirname, 0, 0, 0, 0);
 212         dir = get_record(arc, dirname);
 213         contents_insert(copy_record(rec), dir);
 214         free(dirname);
 215 }
 216
 217
 218
 219 static int read_bytes(zip_archive* arc, void* buf, int count){
 220         return arc->read(arc->userdata, buf, count);
 221 }
 222
 223 static int read_chunk(zip_archive* arc, void* buf, int count){
 224         int n = read_bytes(arc, buf, count);
 225         if(n < 0){
 226                 set_error("read error");
 227                 return -1;
 228         }
 229         if(n < count){
 230                 set_error("not enough data");
 231                 return -1;
 232         }
 233         return 0;
 234 }
 235
 236 static int skip(zip_archive* arc, int count){
 237         char buf[256];
 238         int n;
 239         int total = 0;
 240
 241         while(total != count){
 242                 int diff = count - total;
 243                 int chunk = diff < 256 ? diff : 256;
 244                 n = read_bytes(arc, buf, chunk);
 245                 if(n < 0){
 246                         set_error("read error");
 247                         return -1;
 248                 }
 249                 if(n < chunk){
 250                         set_error("not enough data");
 251                         return -1;
 252                 }
 253                 total += n;
 254         }
 255
 256         return 0;
 257 }
 258
 259 static int read_long(zip_archive* arc, unsigned* n){
 260         unsigned char b[4];
 261         int e = read_bytes(arc, b, 4);
 262         if(e < 0){
 263                 set_error("read error");
 264                 return -1;
 265         }
 266         if(e < 4){
 267                 set_error("not enough data");
 268                 return -1;
 269         }
 270         *n = b[0] | (b[1]<<8) | (b[2]<<16) | (b[3]<<24);
 271         return 0;
 272 }
 273
 274 static int read_short(zip_archive* arc, unsigned* n){
 275         unsigned char b[2];
 276         int e = read_bytes(arc, b, 2);
 277         if(e < 0){
 278                 set_error("read error");
 279                 return -1;
 280         }
 281         if(e < 2){
 282                 set_error("not enough data");
 283                 return -1;
 284         }
 285         *n = b[0] | (b[1]<<8);
 286         return 0;
 287 }
 288
 289
 290 static int parse_local_header(zip_archive* arc){
 291         unsigned L1, L2;
 292         char* filename;
 293         unsigned method;
 294         unsigned clen, ulen;
 295         unsigned offset;
 296         unsigned flags;
 297
 298         if(
 299                 skip(arc, 2) ||
 300                 read_short(arc, &flags) ||
 301                 read_short(arc, &method) ||
 302                 skip(arc, 8) ||
 303                 read_long(arc, &clen) ||
 304                 read_long(arc, &ulen) ||
 305                 read_short(arc, &L1) ||
 306                 read_short(arc, &L2)
 307         ){
 308                 return -1;
 309         }
 310
 311         filename = malloc(L1+1);
 312         if(
 313                 read_chunk(arc, filename, L1) ||
 314                 skip(arc, L2) ||
 315                 skip(arc, clen)
 316         ){
 317                 free(filename);
 318                 return -1;
 319         }
 320
 321         filename[L1] = '\0';
 322         offset = arc->ptr + 30 + L1 + L2;
 323         arc->ptr = offset + clen + (flags&(1<<3) ? 12 : 0);
 324
 325         set_record(arc, filename, ulen, clen, offset, method);
 326
 327         free(filename);
 328
 329         return 0;
 330 }
 331
 332 static int build_directory(zip_archive* arc){
 333         while(1){
 334                 unsigned sig;
 335                 if(read_long(arc, &sig) < 0) return -1;
 336                 else if(sig == 0x04034b50) parse_local_header(arc);
 337                 else break;
 338         }
 339
 340         return 0;
 341 }
 342
 343
 344 static void free_directory_r(struct record* r){
 345         if(r->contents) free_directory_r(r->contents);
 346         if(r->next) free_directory_r(r->next);
 347         free(r->filename);
 348         free(r);
 349 }
 350
 351 static void free_directory(zip_archive* arc){
 352         int i;
 353         for(i=0; i<TABLE_SIZE; i++){
 354                 if(arc->table[i]) free_directory_r(arc->table[i]);
 355         }
 356 }
 357
 358
 359 static int fill_inbuf(zip_file* f){
 360         int nread, nwant;
 361         int nleftstream, nleftbuffer;
 362
 363         /* shift everything left */
 364         memmove(f->inbuf, f->strm.next_in, f->strm.avail_in);
 365         f->strm.next_in = f->inbuf;
 366
 367         /* fill the buffer */
 368         if(f->arc->seek(f->arc->userdata, f->offset+f->cptr, SEEK_SET) < 0){
 369                 set_error("archive seek error");
 370                 return -1;
 371         }
 372
 373         /* you want the minimum of
 374         a) bytes needed to fill the buffer and
 375         b) bytes left in the compressed stream */
 376         nleftstream = f->clen - f->cptr;
 377         nleftbuffer = BUF_SIZE - f->strm.avail_in;
 378         nwant = nleftstream < nleftbuffer ? nleftstream : nleftbuffer;
 379         nread = f->arc->read(f->arc->userdata, f->inbuf+f->strm.avail_in, nwant);
 380         if(nread < 0){
 381                 set_error("archive read error");
 382                 return -1;
 383         }
 384
 385         f->cptr += nread;
 386         f->strm.avail_in += nread;
 387         return nread;
 388 }
 389
 390 static int inflate_chunk(zip_file* f, byte buf[], int count){
 391         f->strm.next_out = buf;
 392         f->strm.avail_out = count;
 393         int e = inflate(&f->strm, Z_SYNC_FLUSH);
 394         switch(e){
 395         case Z_OK:
 396                 return count - f->strm.avail_out;
 397         case Z_STREAM_END:
 398                 f->eof = 1;
 399                 return count - f->strm.avail_out;
 400         case Z_BUF_ERROR:
 401                 return 0;
 402         case Z_NEED_DICT:
 403                 set_error("inflate needs a preset dictionary at this point");
 404                 return -1;
 405         case Z_DATA_ERROR:
 406                 set_error("inflate data error (input corrupted or in wrong format)");
 407                 return -1;
 408         case Z_STREAM_ERROR:
 409                 set_error("inflate stream error (inconsistent stream structure)");
 410                 return -1;
 411         case Z_MEM_ERROR:
 412                 set_error("inflate out of memory");
 413                 return -1;
 414         default:
 415                 set_error("inflate error (unknown)");
 416                 return -1;
 417         }
 418 }
 419
 420
 421 /* these are callbacks for the default archive reader, filesystem i/o */
 422 static int file_read(void* f, byte buf[], int count){
 423         return fread(buf, 1, count, f);
 424 }
 425
 426 static int file_seek(void* f, int offset, int whence){
 427         return fseek(f, offset, whence);
 428 }
 429
 430 static void file_close(void* f){
 431         fclose(f);
 432 }
 433
 434
 435
 436
 437
 438
 439
 440 /* public methods */
 441
 442 zip_archive* zip_aropenf(char* filename){
 443         FILE* f = fopen(filename, "r");
 444         if(f == NULL){
 445                 set_error("i/o error");
 446                 return NULL;
 447         }
 448         zip_reader rd = {file_read, file_seek, file_close, f};
 449         return zip_aropen(&rd);
 450 }
 451
 452 zip_archive* zip_aropen(zip_reader* rd){
 453         int i;
 454         zip_archive* arc = malloc(sizeof(zip_archive));
 455         if(arc == NULL){
 456                 out_of_memory();
 457                 return NULL;
 458         }
 459         arc->read = rd->read;
 460         arc->seek = rd->seek;
 461         arc->close = rd->close;
 462         arc->userdata = rd->userdata;
 463         arc->ptr = 0;
 464
 465         for(i=0; i<TABLE_SIZE; i++){
 466                 arc->table[i] = NULL;
 467         }
 468
 469         if(build_directory(arc) < 0){
 470                 free_directory(arc);
 471                 free(arc);
 472                 return NULL;
 473         }
 474
 475         return arc;
 476 }
 477
 478 void zip_arclose(zip_archive* arc){
 479         arc->close(arc->userdata);
 480         free_directory(arc);
 481         free(arc);
 482 }
 483
 484 zip_file* zip_fopen(zip_archive* arc, char* path){
 485         struct record* r = get_record(arc, path);
 486         if(r == NULL){
 487                 set_error("file not found");
 488                 return NULL;
 489         }
 490
 491         if(r->filename[strlen(r->filename)-1] == '/'){
 492                 set_error("cannot open directory");
 493                 return NULL;
 494         }
 495
 496         if(r->method != 8){
 497                 unrecognized_method(r->method);
 498                 return NULL;
 499         }
 500
 501         zip_file* f = malloc(sizeof(zip_file));
 502         if(f == NULL){
 503                 out_of_memory();
 504                 return NULL;
 505         }
 506
 507         f->eof = 0;
 508         f->arc = arc;
 509         f->strm.zalloc = NULL;
 510         f->strm.zfree = NULL;
 511         f->strm.opaque = NULL;
 512         f->strm.next_in = f->inbuf;
 513         f->strm.avail_in = 0;
 514         f->strm.next_out = NULL;
 515         f->strm.avail_out = 0;
 516         f->clen = r->clen;
 517         f->cptr = 0;
 518         f->ulen = r->ulen;
 519         f->uptr = 0;
 520         f->offset = r->offset;
 521
 522         int e = inflateInit2(&f->strm, -15);
 523         if(e != Z_OK){
 524                 switch(e){
 525                         case Z_MEM_ERROR: set_error("memory"); break;
 526                         case Z_STREAM_ERROR: set_error("stream"); break;
 527                 }
 528                 free(f);
 529                 return NULL;
 530         }
 531
 532         return f;
 533 }
 534
 535 void zip_fclose(zip_file* f){
 536         inflateEnd(&f->strm);
 537         free(f);
 538 }
 539
 540 int zip_fread(zip_file* f, byte buf[], int count){
 541         int total = 0;
 542         int n;
 543         int sentry = 0; /* annoying */
 544
 545         while(count > 0 && !f->eof){
 546                 n = inflate_chunk(f, buf+total, count);
 547
 548                 if(n < 0) return -1;
 549                 if(n == 0){
 550                         /* need more input */
 551                         if(fill_inbuf(f) < 0) return -1;
 552                         if(sentry == 1){
 553                                 set_error("unable to satisfy buffer requirements");
 554                                 return -1;
 555                         }
 556                         sentry = 1;
 557                         continue;
 558                 }
 559
 560                 sentry = 0;
 561                 count -= n;
 562                 total += n;
 563
 564                 f->uptr += n;
 565                 if(f->uptr == f->ulen){
 566                         f->eof = 1;
 567                 }
 568         }
 569
 570         return total;
 571 }
 572
 573 int zip_feof(zip_file* f){
 574         return f->eof;
 575 }
 576
 577
 578
 579
 580 zip_dir* zip_opendir(zip_archive* arc, char* path){
 581         if(path[strlen(path)-1] != '/'){
 582                 set_error("path does not specify directory");
 583                 return NULL;
 584         }
 585
 586         zip_dir* dir = malloc(sizeof(zip_dir));
 587         if(dir == NULL){
 588                 out_of_memory();
 589                 return NULL;
 590         }
 591
 592         struct record* r = get_record(arc, path);
 593         if(r == NULL){
 594                 set_error("file not found");
 595                 free(dir);
 596                 return NULL;
 597         }
 598
 599         dir->ptr = r->contents;
 600         return dir;
 601 }
 602
 603 char* zip_readdir(zip_dir* dir){
 604         if(dir->ptr == NULL){
 605                 /* no more entries, not an error */
 606                 return NULL;
 607         }
 608         else{
 609                 char* filename = dir->ptr->filename;
 610                 dir->ptr = dir->ptr->next;
 611                 return filename;
 612         }
 613 }
 614
 615 void zip_closedir(zip_dir* dir){
 616         free(dir);
 617 }
 618
 619
 620 char* zip_geterror(){
 621         return errbuf;
 622 }