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 "libbb.h"
  29
  30 extern void seek_sub_file(FILE *src_stream, const int count);
  31 extern char *extract_archive(FILE *src_stream, FILE *out_stream, const file_header_t *file_entry,
  32  const int function, const char *prefix);
  33
  34
  35 #ifdef L_archive_offset
  36 off_t archive_offset;
  37 #else
  38 extern off_t archive_offset;
  39 #endif
  40
  41 #ifdef L_seek_sub_file
  42 void seek_sub_file(FILE *src_stream, const int count)
  43 {
  44         int i;
  45         /* Try to fseek as faster */
  46         archive_offset += count;
  47         if (fseek(src_stream, count, SEEK_CUR) != 0 && errno == ESPIPE) {
  48         for (i = 0; i < count; i++) {
  49                 fgetc(src_stream);
  50                 }
  51         }
  52         return;
  53 }
  54 #endif
  55
  56
  57
  58 #ifdef L_extract_archive
  59 /* Extract the data postioned at src_stream to either filesystem, stdout or
  60  * buffer depending on the value of 'function' which is defined in libbb.h
  61  *
  62  * prefix doesnt have to be just a directory, it may prefix the filename as well.
  63  *
  64  * e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath
  65  * '/var/lib/dpkg/info/' and all files/dirs created in that dir will have
  66  * 'dpkg.' as their prefix
  67  *
  68  * For this reason if prefix does point to a dir then it must end with a
  69  * trailing '/' or else the last dir will be assumed to be the file prefix
  70  */
  71 char *extract_archive(FILE *src_stream, FILE *out_stream, const file_header_t *file_entry,
  72  const int function, const char *prefix)
  73 {
  74         FILE *dst_stream = NULL;
  75         char *full_name = NULL;
  76         char *buffer = NULL;
  77         struct utimbuf t;
  78
  79         /* prefix doesnt have to be a proper path it may prepend
  80          * the filename as well */
  81         if (prefix != NULL) {
  82                 /* strip leading '/' in filename to extract as prefix may not be dir */
  83                 /* Cant use concat_path_file here as prefix might not be a directory */
  84                 char *path = file_entry->name;
  85                 if (strncmp("./", path, 2) == 0) {
  86                         path += 2;
  87                         if (strlen(path) == 0) {
  88                                 return(NULL);
  89                         }
  90                 }
  91                 full_name = xmalloc(strlen(prefix) + strlen(path) + 1);
  92                 strcpy(full_name, prefix);
  93                 strcat(full_name, path);
  94         } else {
  95                 full_name = file_entry->name;
  96         }
  97         if (function & extract_to_stdout) {
  98                 if (S_ISREG(file_entry->mode)) {
  99                         copy_file_chunk(src_stream, out_stream, file_entry->size);
 100                         archive_offset += file_entry->size;
 101                 }
 102         }
 103         else if (function & extract_one_to_buffer) {
 104                 if (S_ISREG(file_entry->mode)) {
 105                         buffer = (char *) xmalloc(file_entry->size + 1);
 106                         fread(buffer, 1, file_entry->size, src_stream);
 107                         buffer[file_entry->size] = '\0';
 108                         archive_offset += file_entry->size;
 109                         return(buffer);
 110                 }
 111         }
 112         else if (function & extract_all_to_fs) {
 113                 struct stat oldfile;
 114                 int stat_res;
 115                 stat_res = lstat (full_name, &oldfile);
 116                 if (stat_res == 0) { /* The file already exists */
 117                         if ((function & extract_unconditional) || (oldfile.st_mtime < file_entry->mtime)) {
 118                                 if (!S_ISDIR(oldfile.st_mode)) {
 119                                         unlink(full_name); /* Directories might not be empty etc */
 120                                 }
 121                         } else {
 122                                 if ((function & extract_quiet) != extract_quiet) {
 123                                         error_msg("%s not created: newer or same age file exists", file_entry->name);
 124                                 }
 125                                 seek_sub_file(src_stream, file_entry->size);
 126                                 return (NULL);
 127                         }
 128                 }
 129                 if (function & extract_create_leading_dirs) { /* Create leading directories with default umask */
 130                         char *parent = dirname(full_name);
 131                         if (make_directory (parent, -1, FILEUTILS_RECUR) != 0) {
 132                                 if ((function & extract_quiet) != extract_quiet) {
 133                                         error_msg("couldn't create leading directories");
 134                                 }
 135                         }
 136                         free (parent);
 137                 }
 138                 switch(file_entry->mode & S_IFMT) {
 139                         case S_IFREG:
 140                                 if (file_entry->link_name) { /* Found a cpio hard link */
 141                                         if (link(file_entry->link_name, full_name) != 0) {
 142                                                 if ((function & extract_quiet) != extract_quiet) {
 143                                                         perror_msg("Cannot link from %s to '%s'",
 144                                                                 file_entry->name, file_entry->link_name);
 145                                                 }
 146                                         }
 147                                 } else {
 148                                         if ((dst_stream = wfopen(full_name, "w")) == NULL) {
 149                                                 seek_sub_file(src_stream, file_entry->size);
 150                                                 return NULL;
 151                                         }
 152                                         archive_offset += file_entry->size;
 153                                         copy_file_chunk(src_stream, dst_stream, file_entry->size);
 154                                         fclose(dst_stream);
 155                                 }
 156                                 break;
 157                         case S_IFDIR:
 158                                 if (stat_res != 0) {
 159                                         if (mkdir(full_name, file_entry->mode) < 0) {
 160                                                 if ((function & extract_quiet) != extract_quiet) {
 161                                                         perror_msg("extract_archive: ");
 162                                                 }
 163                                         }
 164                                 }
 165                                 break;
 166                         case S_IFLNK:
 167                                 if (symlink(file_entry->link_name, full_name) < 0) {
 168                                         if ((function & extract_quiet) != extract_quiet) {
 169                                                 perror_msg("Cannot create symlink from %s to '%s'", file_entry->name, file_entry->link_name);
 170                                         }
 171                                         return NULL;
 172                                 }
 173                                 break;
 174                         case S_IFSOCK:
 175                         case S_IFBLK:
 176                         case S_IFCHR:
 177                         case S_IFIFO:
 178                                 if (mknod(full_name, file_entry->mode, file_entry->device) == -1) {
 179                                         if ((function & extract_quiet) != extract_quiet) {
 180                                                 perror_msg("Cannot create node %s", file_entry->name);
 181                                         }
 182                                         return NULL;
 183                                 }
 184                                 break;
 185                 }
 186
 187                 /* Changing a symlink's properties normally changes the properties of the
 188                  * file pointed to, so dont try and change the date or mode, lchown does
 189                  * does the right thing, but isnt available in older versions of libc */
 190                 if (S_ISLNK(file_entry->mode)) {
 191 #if (__GLIBC__ > 2) && (__GLIBC_MINOR__ > 1)
 192                         lchown(full_name, file_entry->uid, file_entry->gid);
 193 #endif
 194                 } else {
 195                         if (function & extract_preserve_date) {
 196                                 t.actime = file_entry->mtime;
 197                                 t.modtime = file_entry->mtime;
 198                                 utime(full_name, &t);
 199                         }
 200                         chmod(full_name, file_entry->mode);
 201                         chown(full_name, file_entry->uid, file_entry->gid);
 202                 }
 203         } else {
 204                 /* If we arent extracting data we have to skip it,
 205                  * if data size is 0 then then just do it anyway
 206                  * (saves testing for it) */
 207                 seek_sub_file(src_stream, file_entry->size);
 208         }
 209
 210         /* extract_list and extract_verbose_list can be used in conjunction
 211          * with one of the above four extraction functions, so do this seperately */
 212         if (function & extract_verbose_list) {
 213                 fprintf(out_stream, "%s %d/%d %8d %s ", mode_string(file_entry->mode),
 214                         file_entry->uid, file_entry->gid,
 215                         (int) file_entry->size, time_string(file_entry->mtime));
 216         }
 217         if ((function & extract_list) || (function & extract_verbose_list)){
 218                 /* fputs doesnt add a trailing \n, so use fprintf */
 219                 fprintf(out_stream, "%s\n", file_entry->name);
 220         }
 221
 222         free(full_name);
 223
 224         return(NULL); /* Maybe we should say if failed */
 225 }
 226 #endif
 227
 228 #ifdef L_unarchive
 229 char *unarchive(FILE *src_stream, FILE *out_stream, file_header_t *(*get_headers)(FILE *),
 230         const int extract_function, const char *prefix, char **extract_names)
 231 {
 232         file_header_t *file_entry;
 233         int extract_flag;
 234         int i;
 235         char *buffer = NULL;
 236
 237         archive_offset = 0;
 238         while ((file_entry = get_headers(src_stream)) != NULL) {
 239                 extract_flag = TRUE;
 240                 if (extract_names != NULL) {
 241                         int found_flag = FALSE;
 242                         for(i = 0; extract_names[i] != 0; i++) {
 243                                 if (strcmp(extract_names[i], file_entry->name) == 0) {
 244                                         found_flag = TRUE;
 245                                         break;
 246                                 }
 247                         }
 248                         if (extract_function & extract_exclude_list) {
 249                                 if (found_flag == TRUE) {
 250                                         extract_flag = FALSE;
 251                                 }
 252                         } else {
 253                                 /* If its not found in the include list dont extract it */
 254                                 if (found_flag == FALSE) {
 255                                         extract_flag = FALSE;
 256                                 }
 257                         }
 258
 259                 }
 260
 261                 if (extract_flag == TRUE) {
 262                         buffer = extract_archive(src_stream, out_stream, file_entry, extract_function, prefix);
 263                 } else {
 264                         /* seek past the data entry */
 265                         seek_sub_file(src_stream, file_entry->size);
 266                 }
 267         }
 268         return(buffer);
 269 }
 270 #endif
 271
 272 #ifdef L_get_header_ar
 273 file_header_t *get_header_ar(FILE *src_stream)
 274 {
 275         file_header_t *typed;
 276         union {
 277                 char raw[60];
 278                 struct {
 279                         char name[16];
 280                         char date[12];
 281                         char uid[6];
 282                         char gid[6];
 283                         char mode[8];
 284                         char size[10];
 285                         char magic[2];
 286                 } formated;
 287         } ar;
 288         static char *ar_long_names;
 289
 290         if (fread(ar.raw, 1, 60, src_stream) != 60) {
 291                 return(NULL);
 292         }
 293         archive_offset += 60;
 294         /* align the headers based on the header magic */
 295         if ((ar.formated.magic[0] != '`') || (ar.formated.magic[1] != '\n')) {
 296                 /* some version of ar, have an extra '\n' after each data entry,
 297                  * this puts the next header out by 1 */
 298                 if (ar.formated.magic[1] != '`') {
 299                         error_msg("Invalid magic");
 300                         return(NULL);
 301                 }
 302                 /* read the next char out of what would be the data section,
 303                  * if its a '\n' then it is a valid header offset by 1*/
 304                 archive_offset++;
 305                 if (fgetc(src_stream) != '\n') {
 306                         error_msg("Invalid magic");
 307                         return(NULL);
 308                 }
 309                 /* fix up the header, we started reading 1 byte too early */
 310                 /* raw_header[60] wont be '\n' as it should, but it doesnt matter */
 311                 memmove(ar.raw, &ar.raw[1], 59);
 312         }
 313
 314         typed = (file_header_t *) xcalloc(1, sizeof(file_header_t));
 315
 316         typed->size = (size_t) atoi(ar.formated.size);
 317         /* long filenames have '/' as the first character */
 318         if (ar.formated.name[0] == '/') {
 319                 if (ar.formated.name[1] == '/') {
 320                         /* If the second char is a '/' then this entries data section
 321                          * stores long filename for multiple entries, they are stored
 322                          * in static variable long_names for use in future entries */
 323                         ar_long_names = (char *) xrealloc(ar_long_names, typed->size);
 324                         fread(ar_long_names, 1, typed->size, src_stream);
 325                         archive_offset += typed->size;
 326                         /* This ar entries data section only contained filenames for other records
 327                          * they are stored in the static ar_long_names for future reference */
 328                         return (get_header_ar(src_stream)); /* Return next header */
 329                 } else if (ar.formated.name[1] == ' ') {
 330                         /* This is the index of symbols in the file for compilers */
 331                         seek_sub_file(src_stream, typed->size);
 332                         return (get_header_ar(src_stream)); /* Return next header */
 333                 } else {
 334                         /* The number after the '/' indicates the offset in the ar data section
 335                         (saved in variable long_name) that conatains the real filename */
 336                         if (!ar_long_names) {
 337                                 error_msg("Cannot resolve long file name");
 338                                 return (NULL);
 339                         }
 340                         typed->name = xstrdup(ar_long_names + atoi(&ar.formated.name[1]));
 341                 }
 342         } else {
 343                 /* short filenames */
 344                 typed->name = xcalloc(1, 16);
 345                 strncpy(typed->name, ar.formated.name, 16);
 346         }
 347         typed->name[strcspn(typed->name, " /")]='\0';
 348
 349         /* convert the rest of the now valid char header to its typed struct */
 350         parse_mode(ar.formated.mode, &typed->mode);
 351         typed->mtime = atoi(ar.formated.date);
 352         typed->uid = atoi(ar.formated.uid);
 353         typed->gid = atoi(ar.formated.gid);
 354
 355         return(typed);
 356 }
 357 #endif
 358
 359 #ifdef L_get_header_cpio
 360 struct hardlinks {
 361         file_header_t *entry;
 362         int inode;
 363         struct hardlinks *next;
 364 };
 365
 366 file_header_t *get_header_cpio(FILE *src_stream)
 367 {
 368         file_header_t *cpio_entry = NULL;
 369         char cpio_header[110];
 370         int namesize;
 371         char dummy[16];
 372         int major, minor, nlink, inode;
 373         static struct hardlinks *saved_hardlinks = NULL;
 374         static int pending_hardlinks = 0;
 375
 376         if (pending_hardlinks) { /* Deal with any pending hardlinks */
 377                 struct hardlinks *tmp = saved_hardlinks, *oldtmp = NULL;
 378                 while (tmp) {
 379                         if (tmp->entry->link_name) { /* Found a hardlink ready to be extracted */
 380                                 cpio_entry = tmp->entry;
 381                                 if (oldtmp) oldtmp->next = tmp->next; /* Remove item from linked list */
 382                                 else saved_hardlinks = tmp->next;
 383                                 free(tmp);
 384                                 return (cpio_entry);
 385                         }
 386                         oldtmp = tmp;
 387                         tmp = tmp->next;
 388                 }
 389                 pending_hardlinks = 0; /* No more pending hardlinks, read next file entry */
 390         }
 391
 392         /* There can be padding before archive header */
 393         seek_sub_file(src_stream, (4 - (archive_offset % 4)) % 4);
 394         if (fread(cpio_header, 1, 110, src_stream) == 110) {
 395                 archive_offset += 110;
 396                 if (strncmp(cpio_header, "07070", 5) != 0) {
 397                         error_msg("Unsupported format or invalid magic");
 398                         return(NULL);
 399                 }
 400                 switch (cpio_header[5]) {
 401                         case '2': /* "crc" header format */
 402                                 /* Doesnt do the crc check yet */
 403                         case '1': /* "newc" header format */
 404                                 cpio_entry = (file_header_t *) xcalloc(1, sizeof(file_header_t));
 405                                 sscanf(cpio_header, "%6c%8x%8x%8x%8x%8x%8lx%8lx%16c%8x%8x%8x%8c",
 406                                         dummy, &inode, (unsigned int*)&cpio_entry->mode,
 407                                         (unsigned int*)&cpio_entry->uid, (unsigned int*)&cpio_entry->gid,
 408                                         &nlink, &cpio_entry->mtime, &cpio_entry->size,
 409                                         dummy, &major, &minor, &namesize, dummy);
 410
 411                                 cpio_entry->name = (char *) xcalloc(1, namesize);
 412                                 fread(cpio_entry->name, 1, namesize, src_stream); /* Read in filename */
 413                                 archive_offset += namesize;
 414                                 /* Skip padding before file contents */
 415                                 seek_sub_file(src_stream, (4 - (archive_offset % 4)) % 4);
 416                                 if (strcmp(cpio_entry->name, "TRAILER!!!") == 0) {
 417                                         printf("%d blocks\n", (int) (archive_offset % 512 ? (archive_offset / 512) + 1 : archive_offset / 512)); /* Always round up */
 418                                         if (saved_hardlinks) { /* Bummer - we still have unresolved hardlinks */
 419                                                 struct hardlinks *tmp = saved_hardlinks, *oldtmp = NULL;
 420                                                 while (tmp) {
 421                                                         error_msg("%s not created: cannot resolve hardlink", tmp->entry->name);
 422                                                         oldtmp = tmp;
 423                                                         tmp = tmp->next;
 424                                                         free (oldtmp->entry->name);
 425                                                         free (oldtmp->entry);
 426                                                         free (oldtmp);
 427                                                 }
 428                                                 saved_hardlinks = NULL;
 429                                                 pending_hardlinks = 0;
 430                                         }
 431                                         return(NULL);
 432                                 }
 433
 434                                 if (S_ISLNK(cpio_entry->mode)) {
 435                                         cpio_entry->link_name = (char *) xcalloc(1, cpio_entry->size + 1);
 436                                         fread(cpio_entry->link_name, 1, cpio_entry->size, src_stream);
 437                                         archive_offset += cpio_entry->size;
 438                                         cpio_entry->size = 0; /* Stop possiable seeks in future */
 439                                 }
 440                                 if (nlink > 1 && !S_ISDIR(cpio_entry->mode)) {
 441                                         if (cpio_entry->size == 0) { /* Put file on a linked list for later */
 442                                                 struct hardlinks *new = xmalloc(sizeof(struct hardlinks));
 443                                                 new->next = saved_hardlinks;
 444                                                 new->inode = inode;
 445                                                 new->entry = cpio_entry;
 446                                                 saved_hardlinks = new;
 447                                         return(get_header_cpio(src_stream)); /* Recurse to next file */
 448                                         } else { /* Found the file with data in */
 449                                                 struct hardlinks *tmp = saved_hardlinks;
 450                                                 pending_hardlinks = 1;
 451                                                 while (tmp) {
 452                                                         if (tmp->inode == inode) {
 453                                                                 tmp->entry->link_name = xstrdup(cpio_entry->name);
 454                                                                 nlink--;
 455                                                         }
 456                                                         tmp = tmp->next;
 457                                                 }
 458                                                 if (nlink > 1) error_msg("error resolving hardlink: did you create the archive with GNU cpio 2.0-2.2?");
 459                                         }
 460                                 }
 461                                 cpio_entry->device = (major << 8) | minor;
 462                                 break;
 463                         default:
 464                                 error_msg("Unsupported format");
 465                                 return(NULL);
 466                 }
 467                 if (ferror(src_stream) || feof(src_stream)) {
 468                         perror_msg("Stream error");
 469                         return(NULL);
 470                 }
 471         }
 472         return(cpio_entry);
 473 }
 474 #endif
 475
 476 #ifdef L_get_header_tar
 477 file_header_t *get_header_tar(FILE *tar_stream)
 478 {
 479         union {
 480                 unsigned char raw[512];
 481                 struct {
 482                         char name[100];         /*   0-99 */
 483                         char mode[8];           /* 100-107 */
 484                         char uid[8];            /* 108-115 */
 485                         char gid[8];            /* 116-123 */
 486                         char size[12];          /* 124-135 */
 487                         char mtime[12];         /* 136-147 */
 488                         char chksum[8];         /* 148-155 */
 489                         char typeflag;          /* 156-156 */
 490                         char linkname[100];     /* 157-256 */
 491                         char magic[6];          /* 257-262 */
 492                         char version[2];        /* 263-264 */
 493                         char uname[32];         /* 265-296 */
 494                         char gname[32];         /* 297-328 */
 495                         char devmajor[8];       /* 329-336 */
 496                         char devminor[8];       /* 337-344 */
 497                         char prefix[155];       /* 345-499 */
 498                         char padding[12];       /* 500-512 */
 499                 } formated;
 500         } tar;
 501         file_header_t *tar_entry = NULL;
 502         long i;
 503         long sum = 0;
 504
 505         if (archive_offset % 512 != 0) {
 506                 seek_sub_file(tar_stream, 512 - (archive_offset % 512));
 507         }
 508
 509         if (fread(tar.raw, 1, 512, tar_stream) != 512) {
 510                 /* Unfortunatly its common for tar files to have all sorts of
 511                  * trailing garbage, fail silently */
 512 //              error_msg("Couldnt read header");
 513                 return(NULL);
 514         }
 515         archive_offset += 512;
 516
 517         /* Check header has valid magic, unfortunately some tar files
 518          * have empty (0'ed) tar entries at the end, which will
 519          * cause this to fail, so fail silently for now
 520          */
 521         if (strncmp(tar.formated.magic, "ustar", 5) != 0) {
 522                 return(NULL);
 523         }
 524
 525         /* Do checksum on headers */
 526         for (i =  0; i < 148 ; i++) {
 527                 sum += tar.raw[i];
 528         }
 529         sum += ' ' * 8;
 530         for (i =  156; i < 512 ; i++) {
 531                 sum += tar.raw[i];
 532         }
 533         if (sum != strtol(tar.formated.chksum, NULL, 8)) {
 534                 error_msg("Invalid tar header checksum");
 535                 return(NULL);
 536         }
 537
 538         /* convert to type'ed variables */
 539         tar_entry = xcalloc(1, sizeof(file_header_t));
 540         tar_entry->name = xstrdup(tar.formated.name);
 541
 542         parse_mode(tar.formated.mode, &tar_entry->mode);
 543         tar_entry->uid   = strtol(tar.formated.uid, NULL, 8);
 544         tar_entry->gid   = strtol(tar.formated.gid, NULL, 8);
 545         tar_entry->size  = strtol(tar.formated.size, NULL, 8);
 546         tar_entry->mtime = strtol(tar.formated.mtime, NULL, 8);
 547         tar_entry->link_name  = strlen(tar.formated.linkname) ?
 548             xstrdup(tar.formated.linkname) : NULL;
 549         tar_entry->device = (strtol(tar.formated.devmajor, NULL, 8) << 8) +
 550                 strtol(tar.formated.devminor, NULL, 8);
 551
 552         return(tar_entry);
 553 }
 554 #endif
 555
 556 #ifdef L_deb_extract
 557 char *deb_extract(const char *package_filename, FILE *out_stream,
 558         const int extract_function, const char *prefix, const char *filename)
 559 {
 560         FILE *deb_stream;
 561         FILE *uncompressed_stream = NULL;
 562         file_header_t *ar_header = NULL;
 563         char **file_list = NULL;
 564         char *output_buffer = NULL;
 565         char *ared_file = NULL;
 566         char ar_magic[8];
 567         int gunzip_pid;
 568
 569         if (filename != NULL) {
 570                 file_list = xmalloc(sizeof(char *) * 2);
 571                 file_list[0] = xstrdup(filename);
 572                 file_list[1] = NULL;
 573         }
 574
 575         if (extract_function & extract_control_tar_gz) {
 576                 ared_file = xstrdup("control.tar.gz");
 577         }
 578         else if (extract_function & extract_data_tar_gz) {
 579                 ared_file = xstrdup("data.tar.gz");
 580         }
 581
 582         /* open the debian package to be worked on */
 583         deb_stream = wfopen(package_filename, "r");
 584         if (deb_stream == NULL) {
 585                 return(NULL);
 586         }
 587         /* set the buffer size */
 588         setvbuf(deb_stream, NULL, _IOFBF, 0x8000);
 589
 590         /* check ar magic */
 591         fread(ar_magic, 1, 8, deb_stream);
 592         if (strncmp(ar_magic,"!<arch>",7) != 0) {
 593                 error_msg_and_die("invalid magic");
 594         }
 595         archive_offset = 8;
 596
 597         while ((ar_header = get_header_ar(deb_stream)) != NULL) {
 598                 if (strcmp(ared_file, ar_header->name) == 0) {
 599                         /* open a stream of decompressed data */
 600                         uncompressed_stream = gz_open(deb_stream, &gunzip_pid);
 601                         archive_offset = 0;
 602                         output_buffer = unarchive(uncompressed_stream, out_stream, get_header_tar, extract_function, prefix, file_list);
 603                 }
 604                 seek_sub_file(deb_stream, ar_header->size);
 605         }
 606         gz_close(gunzip_pid);
 607         fclose(deb_stream);
 608         fclose(uncompressed_stream);
 609         free(ared_file);
 610         return(output_buffer);
 611 }
 612 #endif