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 /*
  13 read files from a zip file.
  14
  15 *depends on zlib
  16 *zip archive may be in a file, or accessed using a reader struct
  17 *reader struct must support seeking
  18 *directory listing is supported
  19 *various errors with the archive and i/o are reported via zip_geterror()
  20
  21 *files in the archive are accessed sequentially, no seek supported
  22 *writing is not supported
  23 *zip64 not supported
  24 *only inflate compression method supported
  25
  26 */
  27
  28
  29 #include <stdio.h>
  30 #include <string.h>
  31 #include <stdlib.h>
  32
  33 #include <zlib.h>
  34
  35 #include <zip.h>
  36
  37 #define BUF_SIZE 1024
  38 #define TABLE_SIZE 128
  39 #define EBUF_SIZE 256
  40
  41 struct record {
  42         char* filename;
  43         unsigned offset;
  44         unsigned clen;
  45         unsigned ulen;
  46         unsigned method;
  47         struct record* next;
  48         struct record* contents;
  49 };
  50
  51 struct zip_archive {
  52         int (*read)(void* userdata, byte buf[], int count);
  53         int (*seek)(void* userdata, int offset, int whence);
  54         void (*close)(void* userdata);
  55         void* userdata;
  56
  57         struct record* table[TABLE_SIZE];
  58         int ptr;
  59 };
  60
  61 struct zip_file {
  62         zip_archive* arc;
  63         int cptr, clen;
  64         int uptr, ulen;
  65         int offset;
  66         byte inbuf[BUF_SIZE];
  67         int eof;
  68         z_stream strm;
  69 };
  70
  71 struct zip_dir {
  72         struct record* ptr;
  73 };
  74
  75
  76 static char errbuf[EBUF_SIZE] = "";
  77
  78
  79 /* internal routines */
  80
  81 static void set_error(char* msg){
  82         strncpy(errbuf, msg, EBUF_SIZE);
  83         errbuf[EBUF_SIZE-1] = '\0';
  84 }
  85
  86 static void out_of_memory(){
  87         set_error("OUT OF MEMORY");
  88 }
  89
  90 /* http://www.cse.yorku.ca/~oz/hash.html */
  91 static unsigned long hash(char* str){
  92         unsigned char* ptr = (unsigned char*)str;
  93         unsigned long hash = 5381;
  94         int c;
  95         while((c = *ptr++))
  96                 hash = ((hash << 5) + hash) + c; /* hash * 33 + c */
  97         return hash;
  98 }
  99
 100
 101 static struct record* make_record(char* filename, int ulen, int clen, int offset, int method){
 102         struct record* r = malloc(sizeof(struct record));
 103         if(r == NULL){
 104                 return NULL;
 105         }
 106         r->filename = strdup(filename);
 107         r->clen = clen;
 108         r->ulen = ulen;
 109         r->offset = offset;
 110         r->method = method;
 111         r->next = NULL;
 112         r->contents = NULL;
 113         return r;
 114 }
 115
 116 static struct record* copy_record(struct record* rec){
 117         return make_record(rec->filename, rec->ulen, rec->clen, rec->offset, rec->method);
 118 }
 119
 120 static struct record* get_record(zip_archive* arc, char* filename){
 121         int i = hash(filename) % TABLE_SIZE;
 122         struct record* ptr = arc->table[i];
 123         while(ptr){
 124                 if(strcmp(filename, ptr->filename) == 0){
 125                         return ptr;
 126                 }
 127                 ptr = ptr->next;
 128         }
 129         return NULL;
 130 }
 131
 132 static void hash_insert(zip_archive* arc, struct record* rec){
 133         int i = hash(rec->filename) % TABLE_SIZE;
 134         struct record* ptr = arc->table[i];
 135
 136         if(get_record(arc, rec->filename)){
 137                 fprintf(stderr, "zip: can't insert %s twice\n", rec->filename);
 138                 return;
 139         }
 140
 141         if(ptr == NULL){
 142                 arc->table[i] = rec;
 143                 return;
 144         }
 145
 146         rec->next = ptr;
 147         arc->table[i] = rec;
 148 }
 149
 150 static char* baseof(char* path){
 151         if(strlen(path) < 2) return NULL;
 152         int ptr = strlen(path) - 2;
 153         while(ptr > 0 && path[ptr] != '/') ptr--;
 154         if(ptr == 0) return NULL;
 155         char* result = malloc(ptr+5);
 156         memcpy(result, path, ptr+1);
 157         result[ptr+1] = '\0';
 158         return result;
 159 }
 160
 161 static void contents_insert(struct record* item, struct record* dir){
 162         item->next = dir->contents;
 163         dir->contents = item;
 164 }
 165 /*
 166 static void print_hash(zip_archive* arc){
 167         int i;
 168         struct record* rec;
 169         for(i=0; i<TABLE_SIZE; i++){
 170                 printf("table[%d]: ",i);
 171                 rec = arc->table[i];
 172                 while(rec){
 173                         printf("%p ", rec);
 174                         rec = rec->next;
 175                 }
 176                 printf("\n");
 177         }
 178 }
 179
 180 static void print_zipfile(zip_file* f){
 181         printf("(+0x%x, %u/%uB, cptr +0x%x, uptr %u)\n",
 182         f->offset, f->clen, f->ulen, f->cptr, f->uptr);
 183 }
 184
 185 static void print_record(struct record* rec){
 186         printf("(%s, %uB, %uB, +0x%x, method %u)\n", rec->filename, rec->clen, rec->ulen, rec->offset, rec->method);
 187 }
 188 */
 189 static char* method_str(unsigned method){
 190         switch(method){
 191                 case 0: return "uncompressed";
 192                 case 1: return "shrink";
 193                 case 2:
 194                 case 3:
 195                 case 4:
 196                 case 5: return "reduce";
 197                 case 6: return "implode";
 198                 case 8: return "deflate";
 199                 case 9: return "deflate64";
 200                 case 10: return "IBM TERSE (old)";
 201                 case 12: return "bzip2";
 202                 case 14: return "lzma";
 203                 case 18: return "IBM TERSE (new)";
 204                 case 19: return "IBM LZ77 z";
 205                 case 97: return "WavPack";
 206                 case 98: return "PPMd";
 207                 default: return "unknown";
 208         }
 209 }
 210
 211 static void unrecognized_method(unsigned method){
 212         char buf[64];
 213         snprintf(buf, 64, "unrecognized compression method '%s'", method_str(method));
 214         buf[63] = '\0';
 215         set_error(buf);
 216 }
 217
 218 static void set_record(zip_archive* arc, char* filename, int ulen, int clen, int offset, int method){
 219         struct record* rec;
 220         struct record* dir;
 221         char* dirname;
 222         if(get_record(arc, filename)) return;
 223         rec = make_record(filename, ulen, clen, offset, method);
 224         hash_insert(arc, rec);
 225         dirname = baseof(filename);
 226         if(dirname == NULL) return;
 227         if(get_record(arc, dirname) == NULL)
 228                 set_record(arc, dirname, 0, 0, 0, 0);
 229         dir = get_record(arc, dirname);
 230         contents_insert(copy_record(rec), dir);
 231         free(dirname);
 232 }
 233
 234
 235
 236 static int read_bytes(zip_archive* arc, void* buf, int count){
 237         return arc->read(arc->userdata, buf, count);
 238 }
 239
 240 static int read_chunk(zip_archive* arc, void* buf, int count){
 241         int n = read_bytes(arc, buf, count);
 242         if(n < 0){
 243                 set_error("read error");
 244                 return -1;
 245         }
 246         if(n < count){
 247                 set_error("not enough data");
 248                 return -1;
 249         }
 250         return 0;
 251 }
 252
 253 static int skip(zip_archive* arc, int count){
 254         char buf[256];
 255         int n;
 256         int total = 0;
 257
 258         while(total != count){
 259                 int diff = count - total;
 260                 int chunk = diff < 256 ? diff : 256;
 261                 n = read_bytes(arc, buf, chunk);
 262                 if(n < 0){
 263                         set_error("read error");
 264                         return -1;
 265                 }
 266                 if(n < chunk){
 267                         set_error("not enough data");
 268                         return -1;
 269                 }
 270                 total += n;
 271         }
 272
 273         return 0;
 274 }
 275
 276 static int read_long(zip_archive* arc, unsigned* n){
 277         unsigned char b[4];
 278         int e = read_bytes(arc, b, 4);
 279         if(e < 0){
 280                 set_error("read error");
 281                 return -1;
 282         }
 283         if(e < 4){
 284                 set_error("not enough data");
 285                 return -1;
 286         }
 287         *n = b[0] | (b[1]<<8) | (b[2]<<16) | (b[3]<<24);
 288         return 0;
 289 }
 290
 291 static int read_short(zip_archive* arc, unsigned* n){
 292         unsigned char b[2];
 293         int e = read_bytes(arc, b, 2);
 294         if(e < 0){
 295                 set_error("read error");
 296                 return -1;
 297         }
 298         if(e < 2){
 299                 set_error("not enough data");
 300                 return -1;
 301         }
 302         *n = b[0] | (b[1]<<8);
 303         return 0;
 304 }
 305
 306
 307 static int parse_local_header(zip_archive* arc){
 308         unsigned L1, L2;
 309         char* filename;
 310         unsigned method;
 311         unsigned clen, ulen;
 312         unsigned offset;
 313         unsigned flags;
 314
 315         if(
 316                 skip(arc, 2) ||
 317                 read_short(arc, &flags) ||
 318                 read_short(arc, &method) ||
 319                 skip(arc, 8) ||
 320                 read_long(arc, &clen) ||
 321                 read_long(arc, &ulen) ||
 322                 read_short(arc, &L1) ||
 323                 read_short(arc, &L2)
 324         ){
 325                 return -1;
 326         }
 327
 328         filename = malloc(L1+1);
 329         if(
 330                 read_chunk(arc, filename, L1) ||
 331                 skip(arc, L2) ||
 332                 skip(arc, clen)
 333         ){
 334                 free(filename);
 335                 return -1;
 336         }
 337
 338         filename[L1] = '\0';
 339         offset = arc->ptr + 30 + L1 + L2;
 340         arc->ptr = offset + clen + (flags&(1<<3) ? 12 : 0);
 341
 342         set_record(arc, filename, ulen, clen, offset, method);
 343
 344         free(filename);
 345
 346         return 0;
 347 }
 348
 349 static int build_directory(zip_archive* arc){
 350         while(1){
 351                 unsigned sig;
 352                 if(read_long(arc, &sig) < 0) return -1;
 353                 else if(sig == 0x04034b50) parse_local_header(arc);
 354                 else break;
 355         }
 356
 357         return 0;
 358 }
 359
 360
 361 static void free_directory_r(struct record* r){
 362         if(r->contents) free_directory_r(r->contents);
 363         if(r->next) free_directory_r(r->next);
 364         free(r->filename);
 365         free(r);
 366 }
 367
 368 static void free_directory(zip_archive* arc){
 369         int i;
 370         for(i=0; i<TABLE_SIZE; i++){
 371                 if(arc->table[i]) free_directory_r(arc->table[i]);
 372         }
 373 }
 374
 375
 376 static int fill_inbuf(zip_file* f){
 377         int nread, nwant;
 378         int nleftstream, nleftbuffer;
 379
 380         /* shift everything left */
 381         memmove(f->inbuf, f->strm.next_in, f->strm.avail_in);
 382         f->strm.next_in = f->inbuf;
 383
 384         /* fill the buffer */
 385         if(f->arc->seek(f->arc->userdata, f->offset+f->cptr, SEEK_SET) < 0){
 386                 set_error("archive seek error");
 387                 return -1;
 388         }
 389
 390         /* you want the minimum of
 391         a) bytes needed to fill the buffer and
 392         b) bytes left in the compressed stream */
 393         nleftstream = f->clen - f->cptr;
 394         nleftbuffer = BUF_SIZE - f->strm.avail_in;
 395         nwant = nleftstream < nleftbuffer ? nleftstream : nleftbuffer;
 396         nread = f->arc->read(f->arc->userdata, f->inbuf+f->strm.avail_in, nwant);
 397         if(nread < 0){
 398                 set_error("archive read error");
 399                 return -1;
 400         }
 401
 402         f->cptr += nread;
 403         f->strm.avail_in += nread;
 404         return nread;
 405 }
 406
 407 static int inflate_chunk(zip_file* f, byte buf[], int count){
 408         f->strm.next_out = buf;
 409         f->strm.avail_out = count;
 410         int e = inflate(&f->strm, Z_SYNC_FLUSH);
 411         switch(e){
 412         case Z_OK:
 413                 return count - f->strm.avail_out;
 414         case Z_STREAM_END:
 415                 f->eof = 1;
 416                 return count - f->strm.avail_out;
 417         case Z_BUF_ERROR:
 418                 return 0;
 419         case Z_NEED_DICT:
 420                 set_error("inflate needs a preset dictionary at this point");
 421                 return -1;
 422         case Z_DATA_ERROR:
 423                 set_error("inflate data error (input corrupted or in wrong format)");
 424                 return -1;
 425         case Z_STREAM_ERROR:
 426                 set_error("inflate stream error (inconsistent stream structure)");
 427                 return -1;
 428         case Z_MEM_ERROR:
 429                 set_error("inflate out of memory");
 430                 return -1;
 431         default:
 432                 set_error("inflate error (unknown)");
 433                 return -1;
 434         }
 435 }
 436
 437
 438 /* these are callbacks for the default archive reader, filesystem i/o */
 439 static int file_read(void* f, byte buf[], int count){
 440         return fread(buf, 1, count, f);
 441 }
 442
 443 static int file_seek(void* f, int offset, int whence){
 444         return fseek(f, offset, whence);
 445 }
 446
 447 static void file_close(void* f){
 448         fclose(f);
 449 }
 450
 451
 452
 453
 454
 455
 456
 457 /* public methods */
 458
 459 zip_archive* zip_aropenf(char* filename){
 460         FILE* f = fopen(filename, "r");
 461         if(f == NULL){
 462                 set_error("i/o error");
 463                 return NULL;
 464         }
 465         zip_reader rd = {file_read, file_seek, file_close, f};
 466         return zip_aropen(&rd);
 467 }
 468
 469 zip_archive* zip_aropen(zip_reader* rd){
 470         int i;
 471         zip_archive* arc = malloc(sizeof(zip_archive));
 472         if(arc == NULL){
 473                 out_of_memory();
 474                 return NULL;
 475         }
 476         arc->read = rd->read;
 477         arc->seek = rd->seek;
 478         arc->close = rd->close;
 479         arc->userdata = rd->userdata;
 480         arc->ptr = 0;
 481
 482         for(i=0; i<TABLE_SIZE; i++){
 483                 arc->table[i] = NULL;
 484         }
 485
 486         if(build_directory(arc) < 0){
 487                 free_directory(arc);
 488                 free(arc);
 489                 return NULL;
 490         }
 491
 492         return arc;
 493 }
 494
 495 void zip_arclose(zip_archive* arc){
 496         arc->close(arc->userdata);
 497         free_directory(arc);
 498         free(arc);
 499 }
 500
 501 zip_file* zip_fopen(zip_archive* arc, char* path){
 502         struct record* r = get_record(arc, path);
 503         if(r == NULL){
 504                 set_error("file not found");
 505                 return NULL;
 506         }
 507
 508         if(r->filename[strlen(r->filename)-1] == '/'){
 509                 set_error("cannot open directory");
 510                 return NULL;
 511         }
 512
 513         if(r->method != 8){
 514                 unrecognized_method(r->method);
 515                 return NULL;
 516         }
 517
 518         zip_file* f = malloc(sizeof(zip_file));
 519         if(f == NULL){
 520                 out_of_memory();
 521                 return NULL;
 522         }
 523
 524         f->eof = 0;
 525         f->arc = arc;
 526         f->strm.zalloc = NULL;
 527         f->strm.zfree = NULL;
 528         f->strm.opaque = NULL;
 529         f->strm.next_in = f->inbuf;
 530         f->strm.avail_in = 0;
 531         f->strm.next_out = NULL;
 532         f->strm.avail_out = 0;
 533         f->clen = r->clen;
 534         f->cptr = 0;
 535         f->ulen = r->ulen;
 536         f->uptr = 0;
 537         f->offset = r->offset;
 538
 539         int e = inflateInit2(&f->strm, -15);
 540         if(e != Z_OK){
 541                 switch(e){
 542                         case Z_MEM_ERROR: set_error("memory"); break;
 543                         case Z_STREAM_ERROR: set_error("stream"); break;
 544                 }
 545                 free(f);
 546                 return NULL;
 547         }
 548
 549         return f;
 550 }
 551
 552 void zip_fclose(zip_file* f){
 553         inflateEnd(&f->strm);
 554         free(f);
 555 }
 556
 557 int zip_fread(zip_file* f, byte buf[], int count){
 558         int total = 0;
 559         int n;
 560         int sentry = 0; /* annoying */
 561
 562         while(count > 0 && !f->eof){
 563                 n = inflate_chunk(f, buf+total, count);
 564
 565                 if(n < 0) return -1;
 566                 if(n == 0){
 567                         /* need more input */
 568                         if(fill_inbuf(f) < 0) return -1;
 569                         if(sentry == 1){
 570                                 set_error("unable to satisfy buffer requirements");
 571                                 return -1;
 572                         }
 573                         sentry = 1;
 574                         continue;
 575                 }
 576
 577                 sentry = 0;
 578                 count -= n;
 579                 total += n;
 580
 581                 f->uptr += n;
 582                 if(f->uptr == f->ulen){
 583                         f->eof = 1;
 584                 }
 585         }
 586
 587         return total;
 588 }
 589
 590 int zip_feof(zip_file* f){
 591         return f->eof;
 592 }
 593
 594
 595
 596
 597 zip_dir* zip_opendir(zip_archive* arc, char* path){
 598         if(path[strlen(path)-1] != '/'){
 599                 set_error("path does not specify directory");
 600                 return NULL;
 601         }
 602
 603         zip_dir* dir = malloc(sizeof(zip_dir));
 604         if(dir == NULL){
 605                 out_of_memory();
 606                 return NULL;
 607         }
 608
 609         struct record* r = get_record(arc, path);
 610         if(r == NULL){
 611                 set_error("file not found");
 612                 free(dir);
 613                 return NULL;
 614         }
 615
 616         dir->ptr = r->contents;
 617         return dir;
 618 }
 619
 620 char* zip_readdir(zip_dir* dir){
 621         if(dir->ptr == NULL){
 622                 /* no more entries, not an error */
 623                 return NULL;
 624         }
 625         else{
 626                 char* filename = dir->ptr->filename;
 627                 dir->ptr = dir->ptr->next;
 628                 return filename;
 629         }
 630 }
 631
 632 void zip_closedir(zip_dir* dir){
 633         free(dir);
 634 }
 635
 636
 637 char* zip_geterror(){
 638         return errbuf;
 639 }