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 {
  90         FILE *dst_stream = NULL;
  91         char *full_name = NULL;
  92         char *full_link_name = NULL;
  93         char *buffer = NULL;
  94         struct utimbuf t;
  95
  96
  97         /* prefix doesnt have to be a proper path it may prepend
  98          * the filename as well */
  99         if (prefix != NULL) {
 100                 /* strip leading '/' in filename to extract as prefix may not be dir */
 101                 /* Cant use concat_path_file here as prefix might not be a directory */
 102                 char *path = file_entry->name;
 103                 if (strncmp("./", path, 2) == 0) {
 104                         path += 2;
 105                         if (strlen(path) == 0) {
 106                                 return(NULL);
 107                         }
 108                 }
 109                 full_name = xmalloc(strlen(prefix) + strlen(path) + 1);
 110                 strcpy(full_name, prefix);
 111                 strcat(full_name, path);
 112                 if ( file_entry->link_name ){
 113                    full_link_name = xmalloc(strlen(prefix) + strlen(file_entry->link_name) + 1);
 114                    strcpy(full_link_name, prefix);
 115                    strcat(full_link_name, file_entry->link_name);
 116                 }
 117         } else {
 118                 full_name = xstrdup(file_entry->name);
 119                 if ( file_entry->link_name )
 120                    full_link_name = xstrdup(file_entry->link_name);
 121         }
 122
 123
 124         if (function & extract_to_stream) {
 125                 if (S_ISREG(file_entry->mode)) {
 126                         copy_file_chunk(src_stream, out_stream, file_entry->size);
 127                         archive_offset += file_entry->size;
 128                 }
 129         }
 130         else if (function & extract_one_to_buffer) {
 131                 if (S_ISREG(file_entry->mode)) {
 132                         buffer = (char *) xmalloc(file_entry->size + 1);
 133                         fread(buffer, 1, file_entry->size, src_stream);
 134                         buffer[file_entry->size] = '\0';
 135                         archive_offset += file_entry->size;
 136                         goto cleanup;
 137                 }
 138         }
 139         else if (function & extract_all_to_fs) {
 140                 struct stat oldfile;
 141                 int stat_res;
 142                 stat_res = lstat (full_name, &oldfile);
 143                 if (stat_res == 0) { /* The file already exists */
 144                         if ((function & extract_unconditional) || (oldfile.st_mtime < file_entry->mtime)) {
 145                                 if (!S_ISDIR(oldfile.st_mode)) {
 146                                         unlink(full_name); /* Directories might not be empty etc */
 147                                 }
 148                         } else {
 149                                 if ((function & extract_quiet) != extract_quiet) {
 150                                         error_msg("%s not created: newer or same age file exists", file_entry->name);
 151                                 }
 152                                 seek_sub_file(src_stream, file_entry->size);
 153                                 goto cleanup;
 154                         }
 155                 }
 156                 if (function & extract_create_leading_dirs) { /* Create leading directories with default umask */
 157                         char *buf, *parent;
 158                         buf = xstrdup(full_name);
 159                         parent = dirname(buf);
 160                         if (make_directory (parent, -1, FILEUTILS_RECUR) != 0) {
 161                                 if ((function & extract_quiet) != extract_quiet) {
 162                                         error_msg("couldn't create leading directories");
 163                                 }
 164                         }
 165                         free (buf);
 166                 }
 167                 switch(file_entry->mode & S_IFMT) {
 168                         case S_IFREG:
 169                                 if (file_entry->link_name) { /* Found a cpio hard link */
 170                                         if (link(full_link_name, full_name) != 0) {
 171                                                 if ((function & extract_quiet) != extract_quiet) {
 172                                                         perror_msg("Cannot link from %s to '%s'",
 173                                                                 file_entry->name, file_entry->link_name);
 174                                                 }
 175                                         }
 176                                 } else {
 177                                         if ((dst_stream = wfopen(full_name, "w")) == NULL) {
 178                                                 seek_sub_file(src_stream, file_entry->size);
 179                                                 goto cleanup;
 180                                         }
 181                                         archive_offset += file_entry->size;
 182                                         copy_file_chunk(src_stream, dst_stream, file_entry->size);
 183                                         fclose(dst_stream);
 184                                 }
 185                                 break;
 186                         case S_IFDIR:
 187                                 if (stat_res != 0) {
 188                                         if (mkdir(full_name, file_entry->mode) < 0) {
 189                                                 if ((function & extract_quiet) != extract_quiet) {
 190                                                         perror_msg("extract_archive: %s", full_name);
 191                                                 }
 192                                         }
 193                                 }
 194                                 break;
 195                         case S_IFLNK:
 196                                 if (symlink(file_entry->link_name, full_name) < 0) {
 197                                         if ((function & extract_quiet) != extract_quiet) {
 198                                                 perror_msg("Cannot create symlink from %s to '%s'", file_entry->name, file_entry->link_name);
 199                                         }
 200                                         goto cleanup;
 201                                 }
 202                                 break;
 203                         case S_IFSOCK:
 204                         case S_IFBLK:
 205                         case S_IFCHR:
 206                         case S_IFIFO:
 207                                 if (mknod(full_name, file_entry->mode, file_entry->device) == -1) {
 208                                         if ((function & extract_quiet) != extract_quiet) {
 209                                                 perror_msg("Cannot create node %s", file_entry->name);
 210                                         }
 211                                         goto cleanup;
 212                                 }
 213                                 break;
 214                          default:
 215                             perror_msg("Don't know how to handle %s", full_name);
 216
 217                 }
 218
 219                 /* Changing a symlink's properties normally changes the properties of the
 220                  * file pointed to, so dont try and change the date or mode, lchown does
 221                  * does the right thing, but isnt available in older versions of libc */
 222                 if (S_ISLNK(file_entry->mode)) {
 223 #if (__GLIBC__ > 2) && (__GLIBC_MINOR__ > 1)
 224                         lchown(full_name, file_entry->uid, file_entry->gid);
 225 #endif
 226                 } else {
 227                         if (function & extract_preserve_date) {
 228                                 t.actime = file_entry->mtime;
 229                                 t.modtime = file_entry->mtime;
 230                                 utime(full_name, &t);
 231                         }
 232                         chown(full_name, file_entry->uid, file_entry->gid);
 233                         chmod(full_name, file_entry->mode);
 234                 }
 235         } else {
 236                 /* If we arent extracting data we have to skip it,
 237                  * if data size is 0 then then just do it anyway
 238                  * (saves testing for it) */
 239                 seek_sub_file(src_stream, file_entry->size);
 240         }
 241
 242         /* extract_list and extract_verbose_list can be used in conjunction
 243          * with one of the above four extraction functions, so do this seperately */
 244         if (function & extract_verbose_list) {
 245                 fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(file_entry->mode),
 246                         file_entry->uid, file_entry->gid,
 247                         (int) file_entry->size, time_string(file_entry->mtime));
 248         }
 249         if ((function & extract_list) || (function & extract_verbose_list)){
 250                 /* fputs doesnt add a trailing \n, so use fprintf */
 251                 fprintf(out_stream, "%s\n", file_entry->name);
 252         }
 253
 254 cleanup:
 255         free(full_name);
 256         if ( full_link_name )
 257             free(full_link_name);
 258
 259         return(buffer); /* Maybe we should say if failed */
 260 }
 261
 262 static char *
 263 unarchive(FILE *src_stream, FILE *out_stream,
 264                 file_header_t *(*get_headers)(FILE *),
 265                 void (*free_headers)(file_header_t *),
 266                 const int extract_function,
 267                 const char *prefix,
 268                 const char **extract_names)
 269 {
 270         file_header_t *file_entry;
 271         int extract_flag;
 272         int i;
 273         char *buffer = NULL;
 274
 275         archive_offset = 0;
 276         while ((file_entry = get_headers(src_stream)) != NULL) {
 277                 extract_flag = TRUE;
 278                 /* fprintf(stderr, __FUNCTION__ " getting headers\n"); */
 279                 if (extract_names != NULL) {
 280                         int found_flag = FALSE;
 281                         for(i = 0; extract_names[i] != 0; i++) {
 282                                 if (strcmp(extract_names[i], file_entry->name) == 0) {
 283                                         found_flag = TRUE;
 284                                         break;
 285                                 }
 286                         }
 287                         if (extract_function & extract_exclude_list) {
 288                                 if (found_flag == TRUE) {
 289                                         extract_flag = FALSE;
 290                                 }
 291                         } else {
 292                                 /* If its not found in the include list dont extract it */
 293                                 if (found_flag == FALSE) {
 294                                         extract_flag = FALSE;
 295                                 }
 296                         }
 297
 298                 }
 299
 300                 if (extract_flag == TRUE) {
 301                         /* fprintf(stderr, __FUNCTION__ " extract?\n"); */
 302                         buffer = extract_archive(src_stream, out_stream, file_entry, extract_function, prefix);
 303                         /* fprintf(stderr, __FUNCTION__ " extracted\n"); */
 304                 } else {
 305                         /* seek past the data entry */
 306                         seek_sub_file(src_stream, file_entry->size);
 307                 }
 308                 free_headers(file_entry);
 309         }
 310         /*fprintf(stderr, __FUNCTION__ " goin home\n");*/
 311
 312         return(buffer);
 313 }
 314
 315 static file_header_t *
 316 get_header_ar(FILE *src_stream)
 317 {
 318         file_header_t *typed;
 319         union {
 320                 char raw[60];
 321                 struct {
 322                         char name[16];
 323                         char date[12];
 324                         char uid[6];
 325                         char gid[6];
 326                         char mode[8];
 327                         char size[10];
 328                         char magic[2];
 329                 } formated;
 330         } ar;
 331         static char *ar_long_names;
 332
 333         if (fread(ar.raw, 1, 60, src_stream) != 60) {
 334                 return(NULL);
 335         }
 336         archive_offset += 60;
 337         /* align the headers based on the header magic */
 338         if ((ar.formated.magic[0] != '`') || (ar.formated.magic[1] != '\n')) {
 339                 /* some version of ar, have an extra '\n' after each data entry,
 340                  * this puts the next header out by 1 */
 341                 if (ar.formated.magic[1] != '`') {
 342                         error_msg("Invalid magic");
 343                         return(NULL);
 344                 }
 345                 /* read the next char out of what would be the data section,
 346                  * if its a '\n' then it is a valid header offset by 1*/
 347                 archive_offset++;
 348                 if (fgetc(src_stream) != '\n') {
 349                         error_msg("Invalid magic");
 350                         return(NULL);
 351                 }
 352                 /* fix up the header, we started reading 1 byte too early */
 353                 /* raw_header[60] wont be '\n' as it should, but it doesnt matter */
 354                 memmove(ar.raw, &ar.raw[1], 59);
 355         }
 356
 357         typed = (file_header_t *) xcalloc(1, sizeof(file_header_t));
 358
 359         typed->size = (size_t) atoi(ar.formated.size);
 360         /* long filenames have '/' as the first character */
 361         if (ar.formated.name[0] == '/') {
 362                 if (ar.formated.name[1] == '/') {
 363                         /* If the second char is a '/' then this entries data section
 364                          * stores long filename for multiple entries, they are stored
 365                          * in static variable long_names for use in future entries */
 366                         ar_long_names = (char *) xrealloc(ar_long_names, typed->size);
 367                         fread(ar_long_names, 1, typed->size, src_stream);
 368                         archive_offset += typed->size;
 369                         /* This ar entries data section only contained filenames for other records
 370                          * they are stored in the static ar_long_names for future reference */
 371                         return (get_header_ar(src_stream)); /* Return next header */
 372                 } else if (ar.formated.name[1] == ' ') {
 373                         /* This is the index of symbols in the file for compilers */
 374                         seek_sub_file(src_stream, typed->size);
 375                         return (get_header_ar(src_stream)); /* Return next header */
 376                 } else {
 377                         /* The number after the '/' indicates the offset in the ar data section
 378                         (saved in variable long_name) that conatains the real filename */
 379                         if (!ar_long_names) {
 380                                 error_msg("Cannot resolve long file name");
 381                                 return (NULL);
 382                         }
 383                         typed->name = xstrdup(ar_long_names + atoi(&ar.formated.name[1]));
 384                 }
 385         } else {
 386                 /* short filenames */
 387                 typed->name = xcalloc(1, 16);
 388                 strncpy(typed->name, ar.formated.name, 16);
 389         }
 390         typed->name[strcspn(typed->name, " /")]='\0';
 391
 392         /* convert the rest of the now valid char header to its typed struct */
 393         parse_mode(ar.formated.mode, &typed->mode);
 394         typed->mtime = atoi(ar.formated.date);
 395         typed->uid = atoi(ar.formated.uid);
 396         typed->gid = atoi(ar.formated.gid);
 397
 398         return(typed);
 399 }
 400
 401 static void
 402 free_header_ar(file_header_t *ar_entry)
 403 {
 404         if (ar_entry == NULL)
 405                 return;
 406
 407         free(ar_entry->name);
 408         if (ar_entry->link_name)
 409                 free(ar_entry->link_name);
 410
 411         free(ar_entry);
 412 }
 413
 414
 415 static file_header_t *
 416 get_header_tar(FILE *tar_stream)
 417 {
 418         union {
 419                 unsigned char raw[512];
 420                 struct {
 421                         char name[100];         /*   0-99 */
 422                         char mode[8];           /* 100-107 */
 423                         char uid[8];            /* 108-115 */
 424                         char gid[8];            /* 116-123 */
 425                         char size[12];          /* 124-135 */
 426                         char mtime[12];         /* 136-147 */
 427                         char chksum[8];         /* 148-155 */
 428                         char typeflag;          /* 156-156 */
 429                         char linkname[100];     /* 157-256 */
 430                         char magic[6];          /* 257-262 */
 431                         char version[2];        /* 263-264 */
 432                         char uname[32];         /* 265-296 */
 433                         char gname[32];         /* 297-328 */
 434                         char devmajor[8];       /* 329-336 */
 435                         char devminor[8];       /* 337-344 */
 436                         char prefix[155];       /* 345-499 */
 437                         char padding[12];       /* 500-512 */
 438                 } formated;
 439         } tar;
 440         file_header_t *tar_entry = NULL;
 441         long i;
 442         long sum = 0;
 443
 444         if (archive_offset % 512 != 0) {
 445                 seek_sub_file(tar_stream, 512 - (archive_offset % 512));
 446         }
 447
 448         if (fread(tar.raw, 1, 512, tar_stream) != 512) {
 449                 /* Unfortunatly its common for tar files to have all sorts of
 450                  * trailing garbage, fail silently */
 451 //              error_msg("Couldnt read header");
 452                 return(NULL);
 453         }
 454         archive_offset += 512;
 455
 456         /* Check header has valid magic, unfortunately some tar files
 457          * have empty (0'ed) tar entries at the end, which will
 458          * cause this to fail, so fail silently for now
 459          */
 460         if (strncmp(tar.formated.magic, "ustar", 5) != 0) {
 461 #ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
 462                 if (strncmp(tar.formated.magic, "\0\0\0\0\0", 5) != 0)
 463 #endif
 464                 return(NULL);
 465         }
 466
 467         /* Do checksum on headers */
 468         for (i =  0; i < 148 ; i++) {
 469                 sum += tar.raw[i];
 470         }
 471         sum += ' ' * 8;
 472         for (i =  156; i < 512 ; i++) {
 473                 sum += tar.raw[i];
 474         }
 475         if (sum != strtol(tar.formated.chksum, NULL, 8)) {
 476                 if ( strtol(tar.formated.chksum,NULL,8) != 0 )
 477                         error_msg("Invalid tar header checksum");
 478                 return(NULL);
 479         }
 480
 481         /* convert to type'ed variables */
 482         tar_entry = xcalloc(1, sizeof(file_header_t));
 483
 484 #ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
 485         if (longname) {
 486                 tar_entry->name = longname;
 487                 longname = NULL;
 488         }
 489         else if (linkname) {
 490                 tar_entry->name = linkname;
 491                 linkname = NULL;
 492         } else
 493 #endif
 494         {
 495                 tar_entry->name = xstrndup(tar.formated.name, 100);
 496
 497                 if (tar.formated.prefix[0]) {
 498                         char *temp = tar_entry->name;
 499                         char *prefixTemp = xstrndup(tar.formated.prefix, 155);
 500                         tar_entry->name = concat_path_file(prefixTemp, temp);
 501                         free(temp);
 502                         free(prefixTemp);
 503                 }
 504         }
 505
 506         // tar_entry->name = xstrdup(tar.formated.name);
 507
 508 /*
 509         parse_mode(tar.formated.mode, &tar_entry->mode);
 510 */
 511         tar_entry->mode = 07777 & strtol(tar.formated.mode, NULL, 8);
 512
 513         tar_entry->uid   = strtol(tar.formated.uid, NULL, 8);
 514         tar_entry->gid   = strtol(tar.formated.gid, NULL, 8);
 515         tar_entry->size  = strtol(tar.formated.size, NULL, 8);
 516         tar_entry->mtime = strtol(tar.formated.mtime, NULL, 8);
 517         tar_entry->link_name  = *tar.formated.linkname != '\0' ? xstrndup(tar.formated.linkname, 100) : NULL;
 518         tar_entry->device = (strtol(tar.formated.devmajor, NULL, 8) << 8) +
 519                 strtol(tar.formated.devminor, NULL, 8);
 520
 521         /* Fix mode, used by the old format */
 522         switch (tar.formated.typeflag) {
 523         /* hard links are detected as regular files with 0 size and a link name */
 524         case '1':
 525                 tar_entry->mode |= S_IFREG ;
 526                 break;
 527         case 0:
 528         case '0':
 529
 530 # ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
 531                 if (last_char_is(tar_entry->name, '/')) {
 532                         tar_entry->mode |= S_IFDIR;
 533                 } else
 534 # endif
 535                         tar_entry->mode |= S_IFREG;
 536                 break;
 537         case '2':
 538                 tar_entry->mode |= S_IFLNK;
 539                 break;
 540         case '3':
 541                 tar_entry->mode |= S_IFCHR;
 542                 break;
 543         case '4':
 544                 tar_entry->mode |= S_IFBLK;
 545                 break;
 546         case '5':
 547                 tar_entry->mode |= S_IFDIR;
 548                 break;
 549         case '6':
 550                 tar_entry->mode |= S_IFIFO;
 551                 break;
 552 # ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
 553         case 'L': {
 554                         longname = xmalloc(tar_entry->size + 1);
 555                         if(fread(longname, tar_entry->size, 1, tar_stream) != 1)
 556                                 return NULL;
 557                         longname[tar_entry->size] = '\0';
 558                         archive_offset += tar_entry->size;
 559
 560                         return(get_header_tar(tar_stream));
 561                 }
 562         case 'K': {
 563                         linkname = xmalloc(tar_entry->size + 1);
 564                         if(fread(linkname, tar_entry->size, 1, tar_stream) != 1)
 565                                 return NULL;
 566                         linkname[tar_entry->size] = '\0';
 567                         archive_offset += tar_entry->size;
 568
 569                         tar_entry->name = linkname;
 570                         return(get_header_tar(tar_stream));
 571                 }
 572         case 'D':
 573         case 'M':
 574         case 'N':
 575         case 'S':
 576         case 'V':
 577                 perror_msg("Ignoring GNU extension type %c", tar.formated.typeflag);
 578 # endif
 579         default:
 580                 perror_msg("Unknown typeflag: 0x%x", tar.formated.typeflag);
 581                 break;
 582
 583         }
 584
 585         return(tar_entry);
 586 }
 587
 588 static void
 589 free_header_tar(file_header_t *tar_entry)
 590 {
 591         if (tar_entry == NULL)
 592                 return;
 593
 594         free(tar_entry->name);
 595         if (tar_entry->link_name);
 596                 free(tar_entry->link_name);
 597
 598         free(tar_entry);
 599 }
 600
 601 char *
 602 deb_extract(const char *package_filename, FILE *out_stream,
 603                   const int extract_function, const char *prefix, const char *filename)
 604 {
 605         FILE *deb_stream = NULL;
 606         file_header_t *ar_header = NULL;
 607         const char **file_list = NULL;
 608         char *output_buffer = NULL;
 609         char *ared_file = NULL;
 610         char ar_magic[8];
 611
 612         if (filename != NULL) {
 613                 file_list = xmalloc(sizeof(char *) * 2);
 614                 file_list[0] = filename;
 615                 file_list[1] = NULL;
 616         }
 617
 618         if (extract_function & extract_control_tar_gz) {
 619                 ared_file = "control.tar.gz";
 620         }
 621         else if (extract_function & extract_data_tar_gz) {
 622                 ared_file = "data.tar.gz";
 623         } else {
 624                 fprintf(stderr, "no file specified to extract -- extract_function=%x\n", extract_function);
 625                 goto cleanup;
 626         }
 627
 628         /* open the debian package to be worked on */
 629         deb_stream = wfopen(package_filename, "r");
 630         if (deb_stream == NULL) {
 631                 goto cleanup;
 632         }
 633         /* set the buffer size */
 634         setvbuf(deb_stream, NULL, _IOFBF, 0x8000);
 635
 636         /* check ar magic */
 637         fread(ar_magic, 1, 8, deb_stream);
 638         /*fprintf(stderr, "deb_extract ar_magic=%08x\n", *(long *)ar_magic);*/
 639         if (strncmp(ar_magic,"!<arch>",7) == 0) {
 640                 archive_offset = 8;
 641
 642                 while ((ar_header = get_header_ar(deb_stream)) != NULL) {
 643                         if (strcmp(ared_file, ar_header->name) == 0) {
 644                                 int gunzip_pid = 0;
 645                                 FILE *uncompressed_stream;
 646                                 /* open a stream of decompressed data */
 647                                 uncompressed_stream = gz_open(deb_stream, &gunzip_pid);
 648                                 if (uncompressed_stream == NULL) {
 649                                         goto cleanup;
 650                                 }
 651
 652                                 archive_offset = 0;
 653                                 output_buffer = unarchive(uncompressed_stream, out_stream, get_header_tar, free_header_tar, extract_function, prefix, file_list);
 654                                 fclose(uncompressed_stream);
 655                                 gz_close(gunzip_pid);
 656                                 free_header_ar(ar_header);
 657                                 break;
 658                         }
 659                         seek_sub_file(deb_stream, ar_header->size);
 660                         free_header_ar(ar_header);
 661                 }
 662                 goto cleanup;
 663         } else if (strncmp(ar_magic, "\037\213", 2) == 0) {
 664                 /* it's a gz file, let's assume it's an opkg */
 665                 int unzipped_opkg_pid;
 666                 FILE *unzipped_opkg_stream;
 667                 file_header_t *tar_header;
 668                 archive_offset = 0;
 669                 fseek(deb_stream, 0, SEEK_SET);
 670                 unzipped_opkg_stream = gz_open(deb_stream, &unzipped_opkg_pid);
 671                 if (unzipped_opkg_stream == NULL) {
 672                         goto cleanup;
 673                 }
 674
 675                 /*fprintf(stderr, __FUNCTION__ ": processing opkg %s -- ared_file=%s\n", package_filename, ared_file);*/
 676                 /* walk through outer tar file to find ared_file */
 677                 while ((tar_header = get_header_tar(unzipped_opkg_stream)) != NULL) {
 678                         int name_offset = 0;
 679                         if (strncmp(tar_header->name, "./", 2) == 0)
 680                                 name_offset = 2;
 681                         if (strcmp(ared_file, tar_header->name+name_offset) == 0) {
 682                                 int gunzip_pid = 0;
 683                                 FILE *uncompressed_stream;
 684                                 /* open a stream of decompressed data */
 685                                 uncompressed_stream = gz_open(unzipped_opkg_stream, &gunzip_pid);
 686                                 if (uncompressed_stream == NULL) {
 687                                         goto cleanup;
 688                                 }
 689                                 archive_offset = 0;
 690                                 /*fprintf(stderr, __FUNCTION__ ":%d: here -- found file\n", __LINE__);*/
 691                                 output_buffer = unarchive(uncompressed_stream,
 692                                                           out_stream,
 693                                                           get_header_tar,
 694                                                           free_header_tar,
 695                                                           extract_function,
 696                                                           prefix,
 697                                                           file_list);
 698                                 /*fprintf(stderr, __FUNCTION__ ":%d: unarchive complete\n", __LINE__);*/
 699                                 free_header_tar(tar_header);
 700                                 fclose(uncompressed_stream);
 701                                 gz_close(gunzip_pid);
 702                                 free_header_tar(tar_header);
 703                                 break;
 704                         }
 705                         seek_sub_file(unzipped_opkg_stream, tar_header->size);
 706                         free_header_tar(tar_header);
 707                 }
 708                 fclose(unzipped_opkg_stream);
 709                 gz_close(unzipped_opkg_pid);
 710                 /*fprintf(stderr, __FUNCTION__ ":%d: done\n", __LINE__);*/
 711                 goto cleanup;
 712         } else {
 713                 error_msg_and_die("invalid magic");
 714         }
 715
 716 cleanup:
 717         if (deb_stream)
 718                 fclose(deb_stream);
 719         if (file_list)
 720                 free(file_list);
 721
 722         return output_buffer;
 723 }