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 #include "gzip.h"
  32
  33 #define CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY 1
  34 #define CONFIG_FEATURE_TAR_GNU_EXTENSIONS
  35
  36 #ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
  37 static char *longname = NULL;
  38 static char *linkname = NULL;
  39 #endif
  40
  41 off_t archive_offset;
  42
  43 static ssize_t seek_forward(struct gzip_handle *zh, ssize_t len)
  44 {
  45         ssize_t slen = gzip_seek(zh, len);
  46
  47         if (slen == len)
  48                 archive_offset += len;
  49
  50         return slen;
  51 }
  52
  53 /* Extract the data postioned at src_stream to either filesystem, stdout or
  54  * buffer depending on the value of 'function' which is defined in libbb.h
  55  *
  56  * prefix doesnt have to be just a directory, it may prefix the filename as well.
  57  *
  58  * e.g. '/var/lib/dpkg/info/dpkg.' will extract all files to the base bath
  59  * '/var/lib/dpkg/info/' and all files/dirs created in that dir will have
  60  * 'dpkg.' as their prefix
  61  *
  62  * For this reason if prefix does point to a dir then it must end with a
  63  * trailing '/' or else the last dir will be assumed to be the file prefix
  64  */
  65 static char *extract_archive(struct gzip_handle *src_stream, FILE * out_stream,
  66                              const file_header_t * file_entry,
  67                              const int function, const char *prefix, int *err)
  68 {
  69         FILE *dst_stream = NULL;
  70         char *full_name = NULL;
  71         char *full_link_name = NULL;
  72         char *buffer = NULL;
  73         struct utimbuf t;
  74
  75         *err = 0;
  76
  77         /* prefix doesnt have to be a proper path it may prepend
  78          * the filename as well */
  79         if (prefix != NULL) {
  80                 /* strip leading '/' in filename to extract as prefix may not be dir */
  81                 /* Cant use concat_path_file here as prefix might not be a directory */
  82                 char *path = file_entry->name;
  83                 if (strncmp("./", path, 2) == 0) {
  84                         path += 2;
  85                         if (strlen(path) == 0)
  86                                 /* Do nothing, current dir already exists. */
  87                                 return NULL;
  88                 }
  89                 full_name = xmalloc(strlen(prefix) + strlen(path) + 1);
  90                 strcpy(full_name, prefix);
  91                 strcat(full_name, path);
  92                 if (file_entry->link_name) {
  93                         full_link_name =
  94                             xmalloc(strlen(prefix) +
  95                                     strlen(file_entry->link_name) + 1);
  96                         strcpy(full_link_name, prefix);
  97                         strcat(full_link_name, file_entry->link_name);
  98                 }
  99         } else {
 100                 full_name = xstrdup(file_entry->name);
 101                 if (file_entry->link_name)
 102                         full_link_name = xstrdup(file_entry->link_name);
 103         }
 104
 105         if (function & extract_to_stream) {
 106                 if (S_ISREG(file_entry->mode)) {
 107                         *err =
 108                             gzip_copy(src_stream, out_stream, file_entry->size);
 109                         archive_offset += file_entry->size;
 110                 }
 111         } else if (function & extract_one_to_buffer) {
 112                 if (S_ISREG(file_entry->mode)) {
 113                         buffer = (char *)xmalloc(file_entry->size + 1);
 114                         gzip_read(src_stream, buffer, file_entry->size);
 115                         buffer[file_entry->size] = '\0';
 116                         archive_offset += file_entry->size;
 117                         goto cleanup;
 118                 }
 119         } else if (function & extract_all_to_fs) {
 120                 struct stat oldfile;
 121                 int stat_res;
 122                 stat_res = lstat(full_name, &oldfile);
 123                 if (stat_res == 0) {    /* The file already exists */
 124                         if ((function & extract_unconditional)
 125                             || (oldfile.st_mtime < file_entry->mtime)) {
 126                                 if (!S_ISDIR(oldfile.st_mode)) {
 127                                         unlink(full_name);      /* Directories might not be empty etc */
 128                                 }
 129                         } else {
 130                                 if ((function & extract_quiet) != extract_quiet) {
 131                                         *err = -1;
 132                                         error_msg
 133                                             ("%s not created: newer or same age file exists",
 134                                              file_entry->name);
 135                                 }
 136                                 seek_forward(src_stream, file_entry->size);
 137                                 goto cleanup;
 138                         }
 139                 }
 140                 if (function & extract_create_leading_dirs) {   /* Create leading directories with default umask */
 141                         char *buf, *parent;
 142                         buf = xstrdup(full_name);
 143                         parent = dirname(buf);
 144                         if (make_directory(parent, -1, FILEUTILS_RECUR) != 0) {
 145                                 if ((function & extract_quiet) != extract_quiet) {
 146                                         *err = -1;
 147                                         error_msg
 148                                             ("couldn't create leading directories");
 149                                 }
 150                         }
 151                         free(buf);
 152                 }
 153                 switch (file_entry->mode & S_IFMT) {
 154                 case S_IFREG:
 155                         if (file_entry->link_name) {    /* Found a cpio hard link */
 156                                 if (link(full_link_name, full_name) != 0) {
 157                                         if ((function & extract_quiet) !=
 158                                             extract_quiet) {
 159                                                 *err = -1;
 160                                                 perror_msg
 161                                                     ("Cannot link from %s to '%s'",
 162                                                      file_entry->name,
 163                                                      file_entry->link_name);
 164                                         }
 165                                 }
 166                         } else {
 167                                 if ((dst_stream =
 168                                      wfopen(full_name, "w")) == NULL) {
 169                                         *err = -1;
 170                                         seek_forward(src_stream,
 171                                                      file_entry->size);
 172                                         goto cleanup;
 173                                 }
 174                                 archive_offset += file_entry->size;
 175                                 *err =
 176                                     gzip_copy(src_stream, dst_stream,
 177                                               file_entry->size);
 178                                 fclose(dst_stream);
 179                         }
 180                         break;
 181                 case S_IFDIR:
 182                         if (stat_res != 0) {
 183                                 if (mkdir(full_name, file_entry->mode) < 0) {
 184                                         if ((function & extract_quiet) !=
 185                                             extract_quiet) {
 186                                                 *err = -1;
 187                                                 perror_msg("Cannot make dir %s",
 188                                                            full_name);
 189                                         }
 190                                 }
 191                         }
 192                         break;
 193                 case S_IFLNK:
 194                         if (symlink(file_entry->link_name, full_name) < 0) {
 195                                 if ((function & extract_quiet) != extract_quiet) {
 196                                         *err = -1;
 197                                         perror_msg
 198                                             ("Cannot create symlink from %s to '%s'",
 199                                              file_entry->name,
 200                                              file_entry->link_name);
 201                                 }
 202                                 goto cleanup;
 203                         }
 204                         break;
 205                 case S_IFSOCK:
 206                 case S_IFBLK:
 207                 case S_IFCHR:
 208                 case S_IFIFO:
 209                         if (mknod
 210                             (full_name, file_entry->mode,
 211                              file_entry->device) == -1) {
 212                                 if ((function & extract_quiet) != extract_quiet) {
 213                                         *err = -1;
 214                                         perror_msg("Cannot create node %s",
 215                                                    file_entry->name);
 216                                 }
 217                                 goto cleanup;
 218                         }
 219                         break;
 220                 default:
 221                         *err = -1;
 222                         perror_msg("Don't know how to handle %s", full_name);
 223
 224                 }
 225
 226                 /* Changing a symlink's properties normally changes the properties of the
 227                  * file pointed to, so dont try and change the date or mode, lchown does
 228                  * does the right thing, but isnt available in older versions of libc */
 229                 if (S_ISLNK(file_entry->mode)) {
 230 #if (__GLIBC__ > 2) && (__GLIBC_MINOR__ > 1)
 231                         lchown(full_name, file_entry->uid, file_entry->gid);
 232 #endif
 233                 } else {
 234                         if (function & extract_preserve_date) {
 235                                 t.actime = file_entry->mtime;
 236                                 t.modtime = file_entry->mtime;
 237                                 utime(full_name, &t);
 238                         }
 239                         chown(full_name, file_entry->uid, file_entry->gid);
 240                         chmod(full_name, file_entry->mode);
 241                 }
 242         } else {
 243                 /* If we arent extracting data we have to skip it,
 244                  * if data size is 0 then then just do it anyway
 245                  * (saves testing for it) */
 246                 seek_forward(src_stream, file_entry->size);
 247         }
 248
 249         /* extract_list and extract_verbose_list can be used in conjunction
 250          * with one of the above four extraction functions, so do this seperately */
 251         if (function & extract_verbose_list) {
 252                 fprintf(out_stream, "%s %d/%d %8d %s ",
 253                         mode_string(file_entry->mode), file_entry->uid,
 254                         file_entry->gid, (int)file_entry->size,
 255                         time_string(file_entry->mtime));
 256         }
 257         if ((function & extract_list) || (function & extract_verbose_list)) {
 258                 /* fputs doesnt add a trailing \n, so use fprintf */
 259                 fprintf(out_stream, "%s\n", file_entry->name);
 260         }
 261
 262 cleanup:
 263         free(full_name);
 264         if (full_link_name)
 265                 free(full_link_name);
 266
 267         return buffer;
 268 }
 269
 270 static char *unarchive(struct gzip_handle *src_stream, FILE * out_stream,
 271                        file_header_t * (*get_headers) (struct gzip_handle *),
 272                        void (*free_headers) (file_header_t *),
 273                        const int extract_function,
 274                        const char *prefix, const char **extract_names, int *err)
 275 {
 276         file_header_t *file_entry;
 277         int extract_flag;
 278         int i;
 279         char *buffer = NULL;
 280
 281         *err = 0;
 282
 283         archive_offset = 0;
 284         while ((file_entry = get_headers(src_stream)) != NULL) {
 285                 extract_flag = TRUE;
 286
 287                 if (extract_names != NULL) {
 288                         int found_flag = FALSE;
 289                         char *p = file_entry->name;
 290
 291                         if (p[0] == '.' && p[1] == '/')
 292                                 p += 2;
 293
 294                         for (i = 0; extract_names[i] != 0; i++) {
 295                                 if (strcmp(extract_names[i], p) == 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                         *err = 0;       /* XXX: ignore extraction errors */
 317                         if (*err) {
 318                                 free_headers(file_entry);
 319                                 break;
 320                         }
 321                 } else {
 322                         /* seek past the data entry */
 323                         seek_forward(src_stream, file_entry->size);
 324                 }
 325                 free_headers(file_entry);
 326         }
 327
 328         return buffer;
 329 }
 330
 331 static file_header_t *get_header_tar(struct gzip_handle *tar_stream)
 332 {
 333         union {
 334                 unsigned char raw[512];
 335                 struct {
 336                         char name[100]; /*   0-99 */
 337                         char mode[8];   /* 100-107 */
 338                         char uid[8];    /* 108-115 */
 339                         char gid[8];    /* 116-123 */
 340                         char size[12];  /* 124-135 */
 341                         char mtime[12]; /* 136-147 */
 342                         char chksum[8]; /* 148-155 */
 343                         char typeflag;  /* 156-156 */
 344                         char linkname[100];     /* 157-256 */
 345                         char magic[6];  /* 257-262 */
 346                         char version[2];        /* 263-264 */
 347                         char uname[32]; /* 265-296 */
 348                         char gname[32]; /* 297-328 */
 349                         char devmajor[8];       /* 329-336 */
 350                         char devminor[8];       /* 337-344 */
 351                         char prefix[155];       /* 345-499 */
 352                         char padding[12];       /* 500-512 */
 353                 } formated;
 354         } tar;
 355         file_header_t *tar_entry = NULL;
 356         long i;
 357         long sum = 0;
 358
 359         if (archive_offset % 512 != 0) {
 360                 seek_forward(tar_stream, 512 - (archive_offset % 512));
 361         }
 362
 363         if (gzip_read(tar_stream, tar.raw, 512) != 512) {
 364                 /* Unfortunately its common for tar files to have all sorts of
 365                  * trailing garbage, fail silently */
 366 //              error_msg("Couldnt read header");
 367                 return (NULL);
 368         }
 369         archive_offset += 512;
 370
 371         /* Check header has valid magic, unfortunately some tar files
 372          * have empty (0'ed) tar entries at the end, which will
 373          * cause this to fail, so fail silently for now
 374          */
 375         if (strncmp(tar.formated.magic, "ustar", 5) != 0) {
 376 #ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
 377                 if (strncmp(tar.formated.magic, "\0\0\0\0\0", 5) != 0)
 378 #endif
 379                         return (NULL);
 380         }
 381
 382         /* Do checksum on headers */
 383         for (i = 0; i < 148; i++) {
 384                 sum += tar.raw[i];
 385         }
 386         sum += ' ' * 8;
 387         for (i = 156; i < 512; i++) {
 388                 sum += tar.raw[i];
 389         }
 390         if (sum != strtol(tar.formated.chksum, NULL, 8)) {
 391                 if (strtol(tar.formated.chksum, NULL, 8) != 0)
 392                         error_msg("Invalid tar header checksum");
 393                 return (NULL);
 394         }
 395
 396         /* convert to type'ed variables */
 397         tar_entry = xcalloc(1, sizeof(file_header_t));
 398
 399         // tar_entry->name = xstrdup(tar.formated.name);
 400
 401 /*
 402         parse_mode(tar.formated.mode, &tar_entry->mode);
 403 */
 404         tar_entry->mode = 07777 & strtol(tar.formated.mode, NULL, 8);
 405
 406         tar_entry->uid = strtol(tar.formated.uid, NULL, 8);
 407         tar_entry->gid = strtol(tar.formated.gid, NULL, 8);
 408         tar_entry->size = strtol(tar.formated.size, NULL, 8);
 409         tar_entry->mtime = strtol(tar.formated.mtime, NULL, 8);
 410
 411         tar_entry->device = (strtol(tar.formated.devmajor, NULL, 8) << 8) +
 412             strtol(tar.formated.devminor, NULL, 8);
 413
 414         /* Fix mode, used by the old format */
 415         switch (tar.formated.typeflag) {
 416                 /* hard links are detected as regular files with 0 size and a link name */
 417         case '1':
 418                 tar_entry->mode |= S_IFREG;
 419                 break;
 420         case 0:
 421         case '0':
 422
 423 #ifdef CONFIG_FEATURE_TAR_OLDGNU_COMPATABILITY
 424                 if (last_char_is(tar_entry->name, '/')) {
 425                         tar_entry->mode |= S_IFDIR;
 426                 } else
 427 #endif
 428                         tar_entry->mode |= S_IFREG;
 429                 break;
 430         case '2':
 431                 tar_entry->mode |= S_IFLNK;
 432                 break;
 433         case '3':
 434                 tar_entry->mode |= S_IFCHR;
 435                 break;
 436         case '4':
 437                 tar_entry->mode |= S_IFBLK;
 438                 break;
 439         case '5':
 440                 tar_entry->mode |= S_IFDIR;
 441                 break;
 442         case '6':
 443                 tar_entry->mode |= S_IFIFO;
 444                 break;
 445 #ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
 446         case 'L':{
 447                         longname = xmalloc(tar_entry->size + 1);
 448                         if (gzip_read(tar_stream, longname, tar_entry->size) !=
 449                             tar_entry->size)
 450                                 return NULL;
 451                         longname[tar_entry->size] = '\0';
 452                         archive_offset += tar_entry->size;
 453
 454                         return (get_header_tar(tar_stream));
 455                 }
 456         case 'K':{
 457                         linkname = xmalloc(tar_entry->size + 1);
 458                         if (gzip_read(tar_stream, linkname, tar_entry->size) !=
 459                             tar_entry->size)
 460                                 return NULL;
 461                         linkname[tar_entry->size] = '\0';
 462                         archive_offset += tar_entry->size;
 463
 464                         return (get_header_tar(tar_stream));
 465                 }
 466         case 'D':
 467         case 'M':
 468         case 'N':
 469         case 'S':
 470         case 'V':
 471                 perror_msg("Ignoring GNU extension type %c",
 472                            tar.formated.typeflag);
 473 #endif
 474         default:
 475                 perror_msg("Unknown typeflag: 0x%x", tar.formated.typeflag);
 476                 break;
 477
 478         }
 479
 480 #ifdef CONFIG_FEATURE_TAR_GNU_EXTENSIONS
 481         if (longname) {
 482                 tar_entry->name = longname;
 483                 longname = NULL;
 484         } else
 485 #endif
 486         {
 487                 tar_entry->name = xstrndup(tar.formated.name, 100);
 488
 489                 if (tar.formated.prefix[0]) {
 490                         char *temp = tar_entry->name;
 491                         char *prefixTemp = xstrndup(tar.formated.prefix, 155);
 492                         tar_entry->name = concat_path_file(prefixTemp, temp);
 493                         free(temp);
 494                         free(prefixTemp);
 495                 }
 496         }
 497
 498         if (linkname) {
 499                 tar_entry->link_name = linkname;
 500                 linkname = NULL;
 501         } else {
 502                 tar_entry->link_name = *tar.formated.linkname != '\0' ?
 503                     xstrndup(tar.formated.linkname, 100) : NULL;
 504         }
 505
 506         return (tar_entry);
 507 }
 508
 509 static void free_header_tar(file_header_t * tar_entry)
 510 {
 511         if (tar_entry == NULL)
 512                 return;
 513
 514         free(tar_entry->name);
 515         if (tar_entry->link_name)
 516                 free(tar_entry->link_name);
 517
 518         free(tar_entry);
 519 }
 520
 521 char *deb_extract(const char *package_filename, FILE * out_stream,
 522                   const int extract_function, const char *prefix,
 523                   const char *filename, int *err)
 524 {
 525         FILE *deb_stream = NULL;
 526         file_header_t *ar_header = NULL;
 527         const char **file_list = NULL;
 528         char *output_buffer = NULL;
 529         char *ared_file = NULL;
 530         char ar_magic[8];
 531         int gz_err;
 532         struct gzip_handle tar_outer = { }, tar_inner = { };
 533         file_header_t *tar_header;
 534         ssize_t len;
 535
 536         *err = 0;
 537
 538         if (filename != NULL) {
 539                 file_list = xmalloc(sizeof(char *) * 2);
 540                 file_list[0] = filename;
 541                 file_list[1] = NULL;
 542         }
 543
 544         if (extract_function & extract_control_tar_gz) {
 545                 ared_file = "control.tar.gz";
 546         } else if (extract_function & extract_data_tar_gz) {
 547                 ared_file = "data.tar.gz";
 548         } else {
 549                 opkg_msg(ERROR, "Internal error: extract_function=%x\n",
 550                          extract_function);
 551                 *err = -1;
 552                 goto cleanup;
 553         }
 554
 555         /* open the debian package to be worked on */
 556         deb_stream = wfopen(package_filename, "r");
 557         if (deb_stream == NULL) {
 558                 *err = -1;
 559                 goto cleanup;
 560         }
 561         /* set the buffer size */
 562         setvbuf(deb_stream, NULL, _IOFBF, 0x8000);
 563
 564         tar_outer.file = deb_stream;
 565         gzip_exec(&tar_outer, NULL);
 566
 567         /* walk through outer tar file to find ared_file */
 568         while ((tar_header = get_header_tar(&tar_outer)) != NULL) {
 569                 int name_offset = 0;
 570                 if (strncmp(tar_header->name, "./", 2) == 0)
 571                         name_offset = 2;
 572
 573                 if (strcmp(ared_file, tar_header->name + name_offset) == 0) {
 574                         tar_inner.gzip = &tar_outer;
 575                         gzip_exec(&tar_inner, NULL);
 576
 577                         archive_offset = 0;
 578
 579                         output_buffer = unarchive(&tar_inner,
 580                                                   out_stream,
 581                                                   get_header_tar,
 582                                                   free_header_tar,
 583                                                   extract_function,
 584                                                   prefix, file_list, err);
 585
 586                         free_header_tar(tar_header);
 587                         gzip_close(&tar_inner);
 588                         break;
 589                 }
 590
 591                 seek_forward(&tar_outer, tar_header->size);
 592                 free_header_tar(tar_header);
 593         }
 594
 595 cleanup:
 596         gzip_close(&tar_outer);
 597
 598         if (file_list)
 599                 free(file_list);
 600
 601         return output_buffer;
 602 }