libbb/unarchive.c

   1 /*
   2  *  Copyright (C) 2000 by Glenn McGrath
   3  *  Copyright (C) 2001 by Laurence Anderson
   4  *
   5  *  Based on previous work by busybox developers and others.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 2 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU Library General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, write to the Free Software
  19  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20  */
  21
  22 #include <stdio.h>
  23 #include <errno.h>
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <unistd.h>
  27 #include <utime.h>
  28 #include <libgen.h>
  29
  30 #include "libbb.h"
  31
  32 #define CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY 1
  33 #define CONFIG_FEATURE_TAR_GNU_EXTENSIONS
  34
  35 #ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
  36 static char *longname = NULL;
  37 static char *linkname = NULL;
  38 #endif
  39
  40 off_t archive_offset;
  41
  42 #define SEEK_BUF 4096
  43 static ssize_t
  44 seek_by_read(FILE* fd, size_t len)
  45 {
  46         ssize_t cc, total = 0;
  47         char buf[SEEK_BUF];
  48
  49         while (len) {
  50                 cc = fread(buf, sizeof(buf[0]),
  51                                 len > SEEK_BUF ? SEEK_BUF : len,
  52                                 fd);
  53
  54                 total += cc;
  55                 len -= cc;
  56
  57                 if(feof(fd) || ferror(fd))
  58                         break;
  59         }
  60         return total;
  61 }
  62
  63 static void
  64 seek_sub_file(FILE *src_stream, const int count)
  65 {
  66         /* Try to fseek as faster */
  67         archive_offset += count;
  68         seek_by_read(src_stream, count);
  69         return;
  70 }
  71
  72
  73 /* Extract the data postioned at src_stream to either filesystem, stdout or
  74  * buffer depending on the value of 'function' which is defined in libbb.h
  75  *
  76  * prefix doesnt have to be just a directory, it may prefix the filename as well.
  77  *
  78  * e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath
  79  * '/var/lib/dpkg/info/' and all files/dirs created in that dir will have
  80  * 'dpkg.' as their prefix
  81  *
  82  * For this reason if prefix does point to a dir then it must end with a
  83  * trailing '/' or else the last dir will be assumed to be the file prefix
  84  */
  85 static char *
  86 extract_archive(FILE *src_stream, FILE *out_stream,
  87                 const file_header_t *file_entry, const int function,
  88                 const char *prefix,
  89                 int *err)
  90 {
  91         FILE *dst_stream = NULL;
  92         char *full_name = NULL;
  93         char *full_link_name = NULL;
  94         char *buffer = NULL;
  95         struct utimbuf t;
  96
  97         *err = 0;
  98
  99         /* prefix doesnt have to be a proper path it may prepend
 100          * the filename as well */
 101         if (prefix != NULL) {
 102                 /* strip leading '/' in filename to extract as prefix may not be dir */
 103                 /* Cant use concat_path_file here as prefix might not be a directory */
 104                 char *path = file_entry->name;
 105                 if (strncmp("./", path, 2) == 0) {
 106                         path += 2;
 107                         if (strlen(path) == 0)
 108                                 /* Do nothing, current dir already exists. */
 109                                 return NULL;
 110                 }
 111                 full_name = xmalloc(strlen(prefix) + strlen(path) + 1);
 112                 strcpy(full_name, prefix);
 113                 strcat(full_name, path);
 114                 if ( file_entry->link_name ){
 115                    full_link_name = xmalloc(strlen(prefix) + strlen(file_entry->link_name) + 1);
 116                    strcpy(full_link_name, prefix);
 117                    strcat(full_link_name, file_entry->link_name);
 118                 }
 119         } else {
 120                 full_name = xstrdup(file_entry->name);
 121                 if ( file_entry->link_name )
 122                    full_link_name = xstrdup(file_entry->link_name);
 123         }
 124
 125
 126         if (function & extract_to_stream) {
 127                 if (S_ISREG(file_entry->mode)) {
 128                         *err = copy_file_chunk(src_stream, out_stream, file_entry->size);
 129                         archive_offset += file_entry->size;
 130                 }
 131         }
 132         else if (function & extract_one_to_buffer) {
 133                 if (S_ISREG(file_entry->mode)) {
 134                         buffer = (char *) xmalloc(file_entry->size + 1);
 135                         fread(buffer, 1, file_entry->size, src_stream);
 136                         buffer[file_entry->size] = '\0';
 137                         archive_offset += file_entry->size;
 138                         goto cleanup;
 139                 }
 140         }
 141         else if (function & extract_all_to_fs) {
 142                 struct stat oldfile;
 143                 int stat_res;
 144                 stat_res = lstat (full_name, &oldfile);
 145                 if (stat_res == 0) { /* The file already exists */
 146                         if ((function & extract_unconditional) || (oldfile.st_mtime < file_entry->mtime)) {
 147                                 if (!S_ISDIR(oldfile.st_mode)) {
 148                                         unlink(full_name); /* Directories might not be empty etc */
 149                                 }
 150                         } else {
 151                                 if ((function & extract_quiet) != extract_quiet) {
 152                                         *err = -1;
 153                                         error_msg("%s not created: newer or same age file exists", file_entry->name);
 154                                 }
 155                                 seek_sub_file(src_stream, file_entry->size);
 156                                 goto cleanup;
 157                         }
 158                 }
 159                 if (function & extract_create_leading_dirs) { /* Create leading directories with default umask */
 160                         char *buf, *parent;
 161                         buf = xstrdup(full_name);
 162                         parent = dirname(buf);
 163                         if (make_directory (parent, -1, FILEUTILS_RECUR) != 0) {
 164                                 if ((function & extract_quiet) != extract_quiet) {
 165                                         *err = -1;
 166                                         error_msg("couldn't create leading directories");
 167                                 }
 168                         }
 169                         free (buf);
 170                 }
 171                 switch(file_entry->mode & S_IFMT) {
 172                         case S_IFREG:
 173                                 if (file_entry->link_name) { /* Found a cpio hard link */
 174                                         if (link(full_link_name, full_name) != 0) {
 175                                                 if ((function & extract_quiet) != extract_quiet) {
 176                                                         *err = -1;
 177                                                         perror_msg("Cannot link from %s to '%s'",
 178                                                                 file_entry->name, file_entry->link_name);
 179                                                 }
 180                                         }
 181                                 } else {
 182                                         if ((dst_stream = wfopen(full_name, "w")) == NULL) {
 183                                                 *err = -1;
 184                                                 seek_sub_file(src_stream, file_entry->size);
 185                                                 goto cleanup;
 186                                         }
 187                                         archive_offset += file_entry->size;
 188                                         copy_file_chunk(src_stream, dst_stream, file_entry->size);
 189                                         fclose(dst_stream);
 190                                 }
 191                                 break;
 192                         case S_IFDIR:
 193                                 if (stat_res != 0) {
 194                                         if (mkdir(full_name, file_entry->mode) < 0) {
 195                                                 if ((function & extract_quiet) != extract_quiet) {
 196                                                         *err = -1;
 197                                                         perror_msg("%s: %s", __FUNCTION__, full_name);
 198                                                 }
 199                                         }
 200                                 }
 201                                 break;
 202                         case S_IFLNK:
 203                                 if (symlink(file_entry->link_name, full_name) < 0) {
 204                                         if ((function & extract_quiet) != extract_quiet) {
 205                                                 *err = -1;
 206                                                 perror_msg("Cannot create symlink from %s to '%s'", file_entry->name, file_entry->link_name);
 207                                         }
 208                                         goto cleanup;
 209                                 }
 210                                 break;
 211                         case S_IFSOCK:
 212                         case S_IFBLK:
 213                         case S_IFCHR:
 214                         case S_IFIFO:
 215                                 if (mknod(full_name, file_entry->mode, file_entry->device) == -1) {
 216                                         if ((function & extract_quiet) != extract_quiet) {
 217                                                 *err = -1;
 218                                                 perror_msg("Cannot create node %s", file_entry->name);
 219                                         }
 220                                         goto cleanup;
 221                                 }
 222                                 break;
 223                          default:
 224                                 *err = -1;
 225                                 perror_msg("Don't know how to handle %s", full_name);
 226
 227                 }
 228
 229                 /* Changing a symlink's properties normally changes the properties of the
 230                  * file pointed to, so dont try and change the date or mode, lchown does
 231                  * does the right thing, but isnt available in older versions of libc */
 232                 if (S_ISLNK(file_entry->mode)) {
 233 #if (__GLIBC__ > 2) && (__GLIBC_MINOR__ > 1)
 234                         lchown(full_name, file_entry->uid, file_entry->gid);
 235 #endif
 236                 } else {
 237                         if (function & extract_preserve_date) {
 238                                 t.actime = file_entry->mtime;
 239                                 t.modtime = file_entry->mtime;
 240                                 utime(full_name, &t);
 241                         }
 242                         chown(full_name, file_entry->uid, file_entry->gid);
 243                         chmod(full_name, file_entry->mode);
 244                 }
 245         } else {
 246                 /* If we arent extracting data we have to skip it,
 247                  * if data size is 0 then then just do it anyway
 248                  * (saves testing for it) */
 249                 seek_sub_file(src_stream, file_entry->size);
 250         }
 251
 252         /* extract_list and extract_verbose_list can be used in conjunction
 253          * with one of the above four extraction functions, so do this seperately */
 254         if (function & extract_verbose_list) {
 255                 fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(file_entry->mode),
 256                         file_entry->uid, file_entry->gid,
 257                         (int) file_entry->size, time_string(file_entry->mtime));
 258         }
 259         if ((function & extract_list) || (function & extract_verbose_list)){
 260                 /* fputs doesnt add a trailing \n, so use fprintf */
 261                 fprintf(out_stream, "%s\n", file_entry->name);
 262         }
 263
 264 cleanup:
 265         free(full_name);
 266         if ( full_link_name )
 267             free(full_link_name);
 268
 269         return buffer;
 270 }
 271
 272 static char *
 273 unarchive(FILE *src_stream, FILE *out_stream,
 274                 file_header_t *(*get_headers)(FILE *),
 275                 void (*free_headers)(file_header_t *),
 276                 const int extract_function,
 277                 const char *prefix,
 278                 const char **extract_names,
 279                 int *err)
 280 {
 281         file_header_t *file_entry;
 282         int extract_flag;
 283         int i;
 284         char *buffer = NULL;
 285
 286         *err = 0;
 287
 288         archive_offset = 0;
 289         while ((file_entry = get_headers(src_stream)) != NULL) {
 290                 extract_flag = TRUE;
 291
 292                 if (extract_names != NULL) {
 293                         int found_flag = FALSE;
 294                         for(i = 0; extract_names[i] != 0; i++) {
 295                                 if (strcmp(extract_names[i], file_entry->name) == 0) {
 296                                         found_flag = TRUE;
 297                                         break;
 298                                 }
 299                         }
 300                         if (extract_function & extract_exclude_list) {
 301                                 if (found_flag == TRUE) {
 302                                         extract_flag = FALSE;
 303                                 }
 304                         } else {
 305                                 /* If its not found in the include list dont extract it */
 306                                 if (found_flag == FALSE) {
 307                                         extract_flag = FALSE;
 308                                 }
 309                         }
 310                 }
 311
 312                 if (extract_flag == TRUE) {
 313                         buffer = extract_archive(src_stream, out_stream,
 314                                         file_entry, extract_function,
 315                                         prefix, err);
 316                         if (*err) {
 317                                 free_headers(file_entry);
 318                                 break;
 319                         }
 320                 } else {
 321                         /* seek past the data entry */
 322                         seek_sub_file(src_stream, file_entry->size);
 323                 }
 324                 free_headers(file_entry);
 325         }
 326
 327         return buffer;
 328 }
 329
 330 static file_header_t *
 331 get_header_ar(FILE *src_stream)
 332 {
 333         file_header_t *typed;
 334         union {
 335                 char raw[60];
 336                 struct {
 337                         char name[16];
 338                         char date[12];
 339                         char uid[6];
 340                         char gid[6];
 341                         char mode[8];
 342                         char size[10];
 343                         char magic[2];
 344                 } formated;
 345         } ar;
 346         static char *ar_long_names;
 347
 348         if (fread(ar.raw, 1, 60, src_stream) != 60) {
 349                 return(NULL);
 350         }
 351         archive_offset += 60;
 352         /* align the headers based on the header magic */
 353         if ((ar.formated.magic[0] != '`') || (ar.formated.magic[1] != '\n')) {
 354                 /* some version of ar, have an extra '\n' after each data entry,
 355                  * this puts the next header out by 1 */
 356                 if (ar.formated.magic[1] != '`') {
 357                         error_msg("Invalid magic");
 358                         return(NULL);
 359                 }
 360                 /* read the next char out of what would be the data section,
 361                  * if its a '\n' then it is a valid header offset by 1*/
 362                 archive_offset++;
 363                 if (fgetc(src_stream) != '\n') {
 364                         error_msg("Invalid magic");
 365                         return(NULL);
 366                 }
 367                 /* fix up the header, we started reading 1 byte too early */
 368                 /* raw_header[60] wont be '\n' as it should, but it doesnt matter */
 369                 memmove(ar.raw, &ar.raw[1], 59);
 370         }
 371
 372         typed = (file_header_t *) xcalloc(1, sizeof(file_header_t));
 373
 374         typed->size = (size_t) atoi(ar.formated.size);
 375         /* long filenames have '/' as the first character */
 376         if (ar.formated.name[0] == '/') {
 377                 if (ar.formated.name[1] == '/') {
 378                         /* If the second char is a '/' then this entries data section
 379                          * stores long filename for multiple entries, they are stored
 380                          * in static variable long_names for use in future entries */
 381                         ar_long_names = (char *) xrealloc(ar_long_names, typed->size);
 382                         fread(ar_long_names, 1, typed->size, src_stream);
 383                         archive_offset += typed->size;
 384                         /* This ar entries data section only contained filenames for other records
 385                          * they are stored in the static ar_long_names for future reference */
 386                         return (get_header_ar(src_stream)); /* Return next header */
 387                 } else if (ar.formated.name[1] == ' ') {
 388                         /* This is the index of symbols in the file for compilers */
 389                         seek_sub_file(src_stream, typed->size);
 390                         return (get_header_ar(src_stream)); /* Return next header */
 391                 } else {
 392                         /* The number after the '/' indicates the offset in the ar data section
 393                         (saved in variable long_name) that conatains the real filename */
 394                         if (!ar_long_names) {
 395                                 error_msg("Cannot resolve long file name");
 396                                 return (NULL);
 397                         }
 398                         typed->name = xstrdup(ar_long_names + atoi(&ar.formated.name[1]));
 399                 }
 400         } else {
 401                 /* short filenames */
 402                 typed->name = xcalloc(1, 16);
 403                 strncpy(typed->name, ar.formated.name, 16);
 404         }
 405         typed->name[strcspn(typed->name, " /")]='\0';
 406
 407         /* convert the rest of the now valid char header to its typed struct */
 408         parse_mode(ar.formated.mode, &typed->mode);
 409         typed->mtime = atoi(ar.formated.date);
 410         typed->uid = atoi(ar.formated.uid);
 411         typed->gid = atoi(ar.formated.gid);
 412
 413         return(typed);
 414 }
 415
 416 static void
 417 free_header_ar(file_header_t *ar_entry)
 418 {
 419         if (ar_entry == NULL)
 420                 return;
 421
 422         free(ar_entry->name);
 423         if (ar_entry->link_name)
 424                 free(ar_entry->link_name);
 425
 426         free(ar_entry);
 427 }
 428
 429
 430 static file_header_t *
 431 get_header_tar(FILE *tar_stream)
 432 {
 433         union {
 434                 unsigned char raw[512];
 435                 struct {
 436                         char name[100];         /*   0-99 */
 437                         char mode[8];           /* 100-107 */
 438                         char uid[8];            /* 108-115 */
 439                         char gid[8];            /* 116-123 */
 440                         char size[12];          /* 124-135 */
 441                         char mtime[12];         /* 136-147 */
 442                         char chksum[8];         /* 148-155 */
 443                         char typeflag;          /* 156-156 */
 444                         char linkname[100];     /* 157-256 */
 445                         char magic[6];          /* 257-262 */
 446                         char version[2];        /* 263-264 */
 447                         char uname[32];         /* 265-296 */
 448                         char gname[32];         /* 297-328 */
 449                         char devmajor[8];       /* 329-336 */
 450                         char devminor[8];       /* 337-344 */
 451                         char prefix[155];       /* 345-499 */
 452                         char padding[12];       /* 500-512 */
 453                 } formated;
 454         } tar;
 455         file_header_t *tar_entry = NULL;
 456         long i;
 457         long sum = 0;
 458
 459         if (archive_offset % 512 != 0) {
 460                 seek_sub_file(tar_stream, 512 - (archive_offset % 512));
 461         }
 462
 463         if (fread(tar.raw, 1, 512, tar_stream) != 512) {
 464                 /* Unfortunatly its common for tar files to have all sorts of
 465                  * trailing garbage, fail silently */
 466 //              error_msg("Couldnt read header");
 467                 return(NULL);
 468         }
 469         archive_offset += 512;
 470
 471         /* Check header has valid magic, unfortunately some tar files
 472          * have empty (0'ed) tar entries at the end, which will
 473          * cause this to fail, so fail silently for now
 474          */
 475         if (strncmp(tar.formated.magic, "ustar", 5) != 0) {
 476 #ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
 477                 if (strncmp(tar.formated.magic, "\0\0\0\0\0", 5) != 0)
 478 #endif
 479                 return(NULL);
 480         }
 481
 482         /* Do checksum on headers */
 483         for (i =  0; i < 148 ; i++) {
 484                 sum += tar.raw[i];
 485         }
 486         sum += ' ' * 8;
 487         for (i =  156; i < 512 ; i++) {
 488                 sum += tar.raw[i];
 489         }
 490         if (sum != strtol(tar.formated.chksum, NULL, 8)) {
 491                 if ( strtol(tar.formated.chksum,NULL,8) != 0 )
 492                         error_msg("Invalid tar header checksum");
 493                 return(NULL);
 494         }
 495
 496         /* convert to type'ed variables */
 497         tar_entry = xcalloc(1, sizeof(file_header_t));
 498
 499 #ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
 500         if (longname) {
 501                 tar_entry->name = longname;
 502                 longname = NULL;
 503         }
 504         else if (linkname) {
 505                 tar_entry->name = linkname;
 506                 linkname = NULL;
 507         } else
 508 #endif
 509         {
 510                 tar_entry->name = xstrndup(tar.formated.name, 100);
 511
 512                 if (tar.formated.prefix[0]) {
 513                         char *temp = tar_entry->name;
 514                         char *prefixTemp = xstrndup(tar.formated.prefix, 155);
 515                         tar_entry->name = concat_path_file(prefixTemp, temp);
 516                         free(temp);
 517                         free(prefixTemp);
 518                 }
 519         }
 520
 521         // tar_entry->name = xstrdup(tar.formated.name);
 522
 523 /*
 524         parse_mode(tar.formated.mode, &tar_entry->mode);
 525 */
 526         tar_entry->mode = 07777 & strtol(tar.formated.mode, NULL, 8);
 527
 528         tar_entry->uid   = strtol(tar.formated.uid, NULL, 8);
 529         tar_entry->gid   = strtol(tar.formated.gid, NULL, 8);
 530         tar_entry->size  = strtol(tar.formated.size, NULL, 8);
 531         tar_entry->mtime = strtol(tar.formated.mtime, NULL, 8);
 532         tar_entry->link_name  = *tar.formated.linkname != '\0' ? xstrndup(tar.formated.linkname, 100) : NULL;
 533         tar_entry->device = (strtol(tar.formated.devmajor, NULL, 8) << 8) +
 534                 strtol(tar.formated.devminor, NULL, 8);
 535
 536         /* Fix mode, used by the old format */
 537         switch (tar.formated.typeflag) {
 538         /* hard links are detected as regular files with 0 size and a link name */
 539         case '1':
 540                 tar_entry->mode |= S_IFREG ;
 541                 break;
 542         case 0:
 543         case '0':
 544
 545 # ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
 546                 if (last_char_is(tar_entry->name, '/')) {
 547                         tar_entry->mode |= S_IFDIR;
 548                 } else
 549 # endif
 550                         tar_entry->mode |= S_IFREG;
 551                 break;
 552         case '2':
 553                 tar_entry->mode |= S_IFLNK;
 554                 break;
 555         case '3':
 556                 tar_entry->mode |= S_IFCHR;
 557                 break;
 558         case '4':
 559                 tar_entry->mode |= S_IFBLK;
 560                 break;
 561         case '5':
 562                 tar_entry->mode |= S_IFDIR;
 563                 break;
 564         case '6':
 565                 tar_entry->mode |= S_IFIFO;
 566                 break;
 567 # ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
 568         case 'L': {
 569                         longname = xmalloc(tar_entry->size + 1);
 570                         if(fread(longname, tar_entry->size, 1, tar_stream) != 1)
 571                                 return NULL;
 572                         longname[tar_entry->size] = '\0';
 573                         archive_offset += tar_entry->size;
 574
 575                         return(get_header_tar(tar_stream));
 576                 }
 577         case 'K': {
 578                         linkname = xmalloc(tar_entry->size + 1);
 579                         if(fread(linkname, tar_entry->size, 1, tar_stream) != 1)
 580                                 return NULL;
 581                         linkname[tar_entry->size] = '\0';
 582                         archive_offset += tar_entry->size;
 583
 584                         tar_entry->name = linkname;
 585                         return(get_header_tar(tar_stream));
 586                 }
 587         case 'D':
 588         case 'M':
 589         case 'N':
 590         case 'S':
 591         case 'V':
 592                 perror_msg("Ignoring GNU extension type %c", tar.formated.typeflag);
 593 # endif
 594         default:
 595                 perror_msg("Unknown typeflag: 0x%x", tar.formated.typeflag);
 596                 break;
 597
 598         }
 599
 600         return(tar_entry);
 601 }
 602
 603 static void
 604 free_header_tar(file_header_t *tar_entry)
 605 {
 606         if (tar_entry == NULL)
 607                 return;
 608
 609         free(tar_entry->name);
 610         if (tar_entry->link_name);
 611                 free(tar_entry->link_name);
 612
 613         free(tar_entry);
 614 }
 615
 616 char *
 617 deb_extract(const char *package_filename, FILE *out_stream,
 618         const int extract_function, const char *prefix,
 619         const char *filename, int *err)
 620 {
 621         FILE *deb_stream = NULL;
 622         file_header_t *ar_header = NULL;
 623         const char **file_list = NULL;
 624         char *output_buffer = NULL;
 625         char *ared_file = NULL;
 626         char ar_magic[8];
 627
 628         *err = 0;
 629
 630         if (filename != NULL) {
 631                 file_list = xmalloc(sizeof(char *) * 2);
 632                 file_list[0] = filename;
 633                 file_list[1] = NULL;
 634         }
 635
 636         if (extract_function & extract_control_tar_gz) {
 637                 ared_file = "control.tar.gz";
 638         }
 639         else if (extract_function & extract_data_tar_gz) {
 640                 ared_file = "data.tar.gz";
 641         } else {
 642                 fprintf(stderr, "no file specified to extract -- extract_function=%x\n", extract_function);
 643                 *err = -1;
 644                 goto cleanup;
 645         }
 646
 647         /* open the debian package to be worked on */
 648         deb_stream = wfopen(package_filename, "r");
 649         if (deb_stream == NULL) {
 650                 *err = -1;
 651                 goto cleanup;
 652         }
 653         /* set the buffer size */
 654         setvbuf(deb_stream, NULL, _IOFBF, 0x8000);
 655
 656         /* check ar magic */
 657         fread(ar_magic, 1, 8, deb_stream);
 658
 659         if (strncmp(ar_magic,"!<arch>",7) == 0) {
 660                 archive_offset = 8;
 661
 662                 while ((ar_header = get_header_ar(deb_stream)) != NULL) {
 663                         if (strcmp(ared_file, ar_header->name) == 0) {
 664                                 int gunzip_pid = 0;
 665                                 FILE *uncompressed_stream;
 666                                 /* open a stream of decompressed data */
 667                                 uncompressed_stream = gz_open(deb_stream, &gunzip_pid);
 668                                 if (uncompressed_stream == NULL) {
 669                                         printf("%s: %d\n", __FUNCTION__, __LINE__);
 670                                         *err = -1;
 671                                         goto cleanup;
 672                                 }
 673
 674                                 archive_offset = 0;
 675                                 output_buffer = unarchive(uncompressed_stream,
 676                                                 out_stream, get_header_tar,
 677                                                 free_header_tar,
 678                                                 extract_function, prefix,
 679                                                 file_list, err);
 680                                 fclose(uncompressed_stream);
 681                                 gz_close(gunzip_pid);
 682                                 free_header_ar(ar_header);
 683                                 break;
 684                         }
 685                         seek_sub_file(deb_stream, ar_header->size);
 686                         free_header_ar(ar_header);
 687                 }
 688                 goto cleanup;
 689         } else if (strncmp(ar_magic, "\037\213", 2) == 0) {
 690                 /* it's a gz file, let's assume it's an opkg */
 691                 int unzipped_opkg_pid;
 692                 FILE *unzipped_opkg_stream;
 693                 file_header_t *tar_header;
 694                 archive_offset = 0;
 695                 fseek(deb_stream, 0, SEEK_SET);
 696                 unzipped_opkg_stream = gz_open(deb_stream, &unzipped_opkg_pid);
 697                 if (unzipped_opkg_stream == NULL) {
 698                         *err = -1;
 699                         goto cleanup;
 700                 }
 701
 702                 /* walk through outer tar file to find ared_file */
 703                 while ((tar_header = get_header_tar(unzipped_opkg_stream)) != NULL) {
 704                         int name_offset = 0;
 705                         if (strncmp(tar_header->name, "./", 2) == 0)
 706                                 name_offset = 2;
 707                         if (strcmp(ared_file, tar_header->name+name_offset) == 0) {
 708                                 int gunzip_pid = 0;
 709                                 FILE *uncompressed_stream;
 710                                 /* open a stream of decompressed data */
 711                                 uncompressed_stream = gz_open(unzipped_opkg_stream, &gunzip_pid);
 712                                 if (uncompressed_stream == NULL) {
 713                                         *err = -1;
 714                                         goto cleanup;
 715                                 }
 716                                 archive_offset = 0;
 717
 718                                 output_buffer = unarchive(uncompressed_stream,
 719                                                           out_stream,
 720                                                           get_header_tar,
 721                                                           free_header_tar,
 722                                                           extract_function,
 723                                                           prefix,
 724                                                           file_list,
 725                                                           err);
 726
 727                                 free_header_tar(tar_header);
 728                                 fclose(uncompressed_stream);
 729                                 gz_close(gunzip_pid);
 730                                 free_header_tar(tar_header);
 731                                 break;
 732                         }
 733                         seek_sub_file(unzipped_opkg_stream, tar_header->size);
 734                         free_header_tar(tar_header);
 735                 }
 736                 fclose(unzipped_opkg_stream);
 737                 gz_close(unzipped_opkg_pid);
 738
 739                 goto cleanup;
 740         } else {
 741                 *err = -1;
 742                 error_msg("%s: invalid magic", package_filename);
 743         }
 744
 745 cleanup:
 746         if (deb_stream)
 747                 fclose(deb_stream);
 748         if (file_list)
 749                 free(file_list);
 750
 751         return output_buffer;
 752 }