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   1 /*
   2  * extract.c
   3  *
   4  * Support for extracting WIM files.
   5  */
   6
   7 /*
   8  * Copyright (C) 2010 Carl Thijssen
   9  * Copyright (C) 2012 Eric Biggers
  10  *
  11  * This file is part of wimlib, a library for working with WIM files.
  12  *
  13  * wimlib is free software; you can redistribute it and/or modify it under the
  14  * terms of the GNU Lesser General Public License as published by the Free
  15  * Software Foundation; either version 2.1 of the License, or (at your option)
  16  * any later version.
  17  *
  18  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  19  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  20  * A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  21  * details.
  22  *
  23  * You should have received a copy of the GNU Lesser General Public License
  24  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  25  */
  26
  27
  28 #include <dirent.h>
  29 #include <errno.h>
  30 #include <fcntl.h>
  31 #include <string.h>
  32 #include <sys/stat.h>
  33 #include <sys/time.h>
  34 #include <unistd.h>
  35
  36 #include "config.h"
  37 #include "dentry.h"
  38 #include "lookup_table.h"
  39 #include "timestamp.h"
  40 #include "wimlib_internal.h"
  41 #include "xml.h"
  42
  43 #ifdef WITH_NTFS_3G
  44 #include <ntfs-3g/volume.h>
  45 #include <ntfs-3g/security.h>
  46 #endif
  47
  48
  49 /* Internal */
  50 #define WIMLIB_EXTRACT_FLAG_MULTI_IMAGE 0x80000000
  51
  52 static int extract_regular_file_linked(const struct dentry *dentry,
  53                                        const char *output_dir,
  54                                        const char *output_path,
  55                                        int extract_flags,
  56                                        struct lookup_table_entry *lte)
  57 {
  58         /* This mode overrides the normal hard-link extraction and
  59          * instead either symlinks or hardlinks *all* identical files in
  60          * the WIM, even if they are in a different image (in the case
  61          * of a multi-image extraction) */
  62
  63         wimlib_assert(lte->file_on_disk);
  64
  65
  66         if (extract_flags & WIMLIB_EXTRACT_FLAG_HARDLINK) {
  67                 if (link(lte->file_on_disk, output_path) != 0) {
  68                         ERROR_WITH_ERRNO("Failed to hard link "
  69                                          "`%s' to `%s'",
  70                                          output_path, lte->file_on_disk);
  71                         return WIMLIB_ERR_LINK;
  72                 }
  73         } else {
  74                 int num_path_components;
  75                 int num_output_dir_path_components;
  76                 size_t file_on_disk_len;
  77                 char *p;
  78                 const char *p2;
  79                 size_t i;
  80
  81                 wimlib_assert(extract_flags & WIMLIB_EXTRACT_FLAG_SYMLINK);
  82
  83                 num_path_components =
  84                         get_num_path_components(dentry->full_path_utf8) - 1;
  85                 num_output_dir_path_components =
  86                         get_num_path_components(output_dir);
  87
  88                 if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
  89                         num_path_components++;
  90                         num_output_dir_path_components--;
  91                 }
  92                 file_on_disk_len = strlen(lte->file_on_disk);
  93
  94                 char buf[file_on_disk_len + 3 * num_path_components + 1];
  95                 p = &buf[0];
  96
  97                 for (i = 0; i < num_path_components; i++) {
  98                         *p++ = '.';
  99                         *p++ = '.';
 100                         *p++ = '/';
 101                 }
 102                 p2 = lte->file_on_disk;
 103                 while (*p2 == '/')
 104                         p2++;
 105                 while (num_output_dir_path_components--)
 106                         p2 = path_next_part(p2, NULL);
 107                 strcpy(p, p2);
 108                 if (symlink(buf, output_path) != 0) {
 109                         ERROR_WITH_ERRNO("Failed to symlink `%s' to "
 110                                          "`%s'",
 111                                          buf, lte->file_on_disk);
 112                         return WIMLIB_ERR_LINK;
 113                 }
 114
 115         }
 116         return 0;
 117 }
 118
 119 static int extract_regular_file_unlinked(WIMStruct *w,
 120                                          struct dentry *dentry,
 121                                          const char *output_path,
 122                                          int extract_flags,
 123                                          struct lookup_table_entry *lte)
 124 {
 125         /* Normal mode of extraction.  Regular files and hard links are
 126          * extracted in the way that they appear in the WIM. */
 127
 128         int out_fd;
 129         const struct resource_entry *res_entry;
 130         int ret;
 131         const struct list_head *head = &dentry->link_group_list;
 132
 133         if (head->next != head) {
 134                 /* This dentry is one of a hard link set of at least 2 dentries.
 135                  * If one of the other dentries has already been extracted, make
 136                  * a hard link to the file corresponding to this
 137                  * already-extracted directory.  Otherwise, extract the
 138                  * file, and set the dentry->extracted_file field so that other
 139                  * dentries in the hard link group can link to it. */
 140                 struct dentry *other;
 141                 list_for_each_entry(other, head, link_group_list) {
 142                         if (other->extracted_file) {
 143                                 DEBUG("Extracting hard link `%s' => `%s'",
 144                                       output_path, other->extracted_file);
 145                                 if (link(other->extracted_file, output_path) != 0) {
 146                                         ERROR_WITH_ERRNO("Failed to hard link "
 147                                                          "`%s' to `%s'",
 148                                                          output_path,
 149                                                          other->extracted_file);
 150                                         return WIMLIB_ERR_LINK;
 151                                 }
 152                                 return 0;
 153                         }
 154                 }
 155                 FREE(dentry->extracted_file);
 156                 dentry->extracted_file = STRDUP(output_path);
 157                 if (!dentry->extracted_file) {
 158                         ERROR("Failed to allocate memory for filename");
 159                         return WIMLIB_ERR_NOMEM;
 160                 }
 161         }
 162
 163         /* Extract the contents of the file to @output_path. */
 164
 165         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 166         if (out_fd == -1) {
 167                 ERROR_WITH_ERRNO("Failed to open the file `%s' for writing",
 168                                  output_path);
 169                 return WIMLIB_ERR_OPEN;
 170         }
 171
 172         if (!lte) {
 173                 /* Empty file with no lookup table entry */
 174                 DEBUG("Empty file `%s'.", output_path);
 175                 ret = 0;
 176                 goto done;
 177         }
 178
 179
 180         res_entry = &lte->resource_entry;
 181
 182         ret = extract_resource_to_fd(w, res_entry, out_fd,
 183                                      res_entry->original_size);
 184
 185         if (ret != 0) {
 186                 ERROR("Failed to extract resource to `%s'", output_path);
 187                 goto done;
 188         }
 189
 190         if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
 191                 /* Mark the lookup table entry to indicate this file has been
 192                  * extracted. */
 193                 lte->out_refcnt++;
 194                 FREE(lte->file_on_disk);
 195                 lte->file_on_disk = STRDUP(output_path);
 196                 if (!lte->file_on_disk)
 197                         ret = WIMLIB_ERR_NOMEM;
 198         }
 199 done:
 200         if (close(out_fd) != 0) {
 201                 ERROR_WITH_ERRNO("Failed to close file `%s'", output_path);
 202                 ret = WIMLIB_ERR_WRITE;
 203         }
 204         return ret;
 205 }
 206
 207 /*
 208  * Extracts a regular file from the WIM archive.
 209  */
 210 static int extract_regular_file(WIMStruct *w,
 211                                 struct dentry *dentry,
 212                                 const char *output_dir,
 213                                 const char *output_path,
 214                                 int extract_flags)
 215 {
 216         struct lookup_table_entry *lte;
 217
 218         lte = dentry_first_lte(dentry, w->lookup_table);
 219
 220         if ((extract_flags & (WIMLIB_EXTRACT_FLAG_SYMLINK |
 221                               WIMLIB_EXTRACT_FLAG_HARDLINK)) && lte) {
 222                 if (lte->out_refcnt++ != 0)
 223                         return extract_regular_file_linked(dentry, output_dir,
 224                                                            output_path,
 225                                                            extract_flags, lte);
 226                 lte->file_on_disk = STRDUP(output_path);
 227                 if (!lte->file_on_disk)
 228                         return WIMLIB_ERR_NOMEM;
 229         }
 230
 231         return extract_regular_file_unlinked(w, dentry, output_path,
 232                                              extract_flags, lte);
 233
 234 }
 235
 236 static int extract_symlink(const struct dentry *dentry, const char *output_path,
 237                            const WIMStruct *w)
 238 {
 239         char target[4096];
 240         ssize_t ret = dentry_readlink(dentry, target, sizeof(target), w);
 241         if (ret <= 0) {
 242                 ERROR("Could not read the symbolic link from dentry `%s'",
 243                       dentry->full_path_utf8);
 244                 return WIMLIB_ERR_INVALID_DENTRY;
 245         }
 246         ret = symlink(target, output_path);
 247         if (ret != 0) {
 248                 ERROR_WITH_ERRNO("Failed to symlink `%s' to `%s'",
 249                                  output_path, target);
 250                 return WIMLIB_ERR_LINK;
 251         }
 252         return 0;
 253 }
 254
 255 /*
 256  * Extracts a directory from the WIM archive.
 257  *
 258  * @dentry:             The directory entry for the directory.
 259  * @output_path:        The path to which the directory is to be extracted to.
 260  * @return:             True on success, false on failure.
 261  */
 262 static int extract_directory(const char *output_path, bool is_root)
 263 {
 264         int ret;
 265         struct stat stbuf;
 266         ret = stat(output_path, &stbuf);
 267         if (ret == 0) {
 268                 if (S_ISDIR(stbuf.st_mode)) {
 269                         if (!is_root)
 270                                 WARNING("`%s' already exists", output_path);
 271                         return 0;
 272                 } else {
 273                         ERROR("`%s' is not a directory", output_path);
 274                         return WIMLIB_ERR_MKDIR;
 275                 }
 276         } else {
 277                 if (errno != ENOENT) {
 278                         ERROR_WITH_ERRNO("Failed to stat `%s'", output_path);
 279                         return WIMLIB_ERR_STAT;
 280                 }
 281         }
 282         /* Compute the output path directory to the directory. */
 283         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP |
 284                                S_IROTH | S_IXOTH) != 0) {
 285                 ERROR_WITH_ERRNO("Cannot create directory `%s'",
 286                                  output_path);
 287                 return WIMLIB_ERR_MKDIR;
 288         }
 289         return 0;
 290 }
 291
 292 struct extract_args {
 293         WIMStruct *w;
 294         int extract_flags;
 295         const char *output_dir;
 296 #ifdef WITH_NTFS_3G
 297         struct SECURITY_API *scapi;
 298 #endif
 299 };
 300
 301 /*
 302  * Extracts a file, directory, or symbolic link from the WIM archive.  For use
 303  * in for_dentry_in_tree().
 304  */
 305 static int extract_dentry(struct dentry *dentry, void *arg)
 306 {
 307         struct extract_args *args = arg;
 308         WIMStruct *w = args->w;
 309         int extract_flags = args->extract_flags;
 310         size_t len = strlen(args->output_dir);
 311         char output_path[len + dentry->full_path_utf8_len + 1];
 312         int ret;
 313
 314         if (extract_flags & WIMLIB_EXTRACT_FLAG_VERBOSE) {
 315                 wimlib_assert(dentry->full_path_utf8);
 316                 puts(dentry->full_path_utf8);
 317         }
 318
 319         memcpy(output_path, args->output_dir, len);
 320         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 321         output_path[len + dentry->full_path_utf8_len] = '\0';
 322
 323         if (dentry_is_symlink(dentry))
 324                 ret = extract_symlink(dentry, output_path, w);
 325         else if (dentry_is_directory(dentry))
 326                 ret = extract_directory(output_path, dentry_is_root(dentry));
 327         else
 328                 ret = extract_regular_file(w, dentry, args->output_dir,
 329                                             output_path, extract_flags);
 330         if (ret != 0)
 331                 return ret;
 332
 333         return 0;
 334 }
 335
 336 static int apply_dentry_timestamps(struct dentry *dentry, void *arg)
 337 {
 338         struct extract_args *args = arg;
 339         size_t len = strlen(args->output_dir);
 340         char output_path[len + dentry->full_path_utf8_len + 1];
 341
 342         memcpy(output_path, args->output_dir, len);
 343         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 344         output_path[len + dentry->full_path_utf8_len] = '\0';
 345
 346         struct timeval tv[2];
 347         wim_timestamp_to_timeval(dentry->last_access_time, &tv[0]);
 348         wim_timestamp_to_timeval(dentry->last_write_time, &tv[1]);
 349         if (lutimes(output_path, tv) != 0) {
 350                 WARNING("Failed to set timestamp on file `%s': %s",
 351                         output_path, strerror(errno));
 352         }
 353         return 0;
 354 }
 355
 356
 357 static int extract_single_image(WIMStruct *w, int image,
 358                                 const char *output_dir, int extract_flags)
 359 {
 360         DEBUG("Extracting image %d", image);
 361
 362         int ret;
 363         ret = wimlib_select_image(w, image);
 364         if (ret != 0)
 365                 return ret;
 366
 367         struct extract_args args = {
 368                 .w = w,
 369                 .extract_flags = extract_flags,
 370                 .output_dir = output_dir,
 371         #ifdef WITH_NTFS_3G
 372                 .scapi = NULL
 373         #endif
 374         };
 375
 376         ret = for_dentry_in_tree(wim_root_dentry(w), extract_dentry, &args);
 377         if (ret != 0)
 378                 return ret;
 379         return for_dentry_in_tree_depth(wim_root_dentry(w),
 380                                         apply_dentry_timestamps, &args);
 381
 382 }
 383
 384
 385 /* Extracts all images from the WIM to @output_dir, with the images placed in
 386  * subdirectories named by their image names. */
 387 static int extract_all_images(WIMStruct *w, const char *output_dir,
 388                               int extract_flags)
 389 {
 390         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 391         size_t output_path_len = strlen(output_dir);
 392         char buf[output_path_len + 1 + image_name_max_len + 1];
 393         int ret;
 394         int image;
 395         const char *image_name;
 396
 397         DEBUG("Attempting to extract all images from `%s'", w->filename);
 398
 399         ret = extract_directory(output_dir, true);
 400         if (ret != 0)
 401                 return ret;
 402
 403         memcpy(buf, output_dir, output_path_len);
 404         buf[output_path_len] = '/';
 405         for (image = 1; image <= w->hdr.image_count; image++) {
 406
 407                 image_name = wimlib_get_image_name(w, image);
 408                 if (*image_name) {
 409                         strcpy(buf + output_path_len + 1, image_name);
 410                 } else {
 411                         /* Image name is empty. Use image number instead */
 412                         sprintf(buf + output_path_len + 1, "%d", image);
 413                 }
 414                 ret = extract_single_image(w, image, buf, extract_flags);
 415                 if (ret != 0)
 416                         goto done;
 417         }
 418 done:
 419         /* Restore original output directory */
 420         buf[output_path_len + 1] = '\0';
 421         return 0;
 422 }
 423
 424 /* Extracts a single image or all images from a WIM file. */
 425 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image,
 426                                    const char *output_dir, int flags)
 427 {
 428
 429         if (!output_dir)
 430                 return WIMLIB_ERR_INVALID_PARAM;
 431
 432         if ((flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 433                         == (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 434                 return WIMLIB_ERR_INVALID_PARAM;
 435
 436
 437         /*ntfs_initialize_file_security(*/
 438
 439         for_lookup_table_entry(w->lookup_table, zero_out_refcnts, NULL);
 440
 441         if (image == WIM_ALL_IMAGES) {
 442                 flags |= WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 443                 return extract_all_images(w, output_dir, flags);
 444         } else {
 445                 flags &= ~WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 446                 return extract_single_image(w, image, output_dir, flags);
 447         }
 448
 449 }
 450
 451 WIMLIBAPI int wimlib_apply_image_to_ntfs_volume(WIMStruct *w, int image,
 452                                                 const char *device, int flags)
 453 {
 454         if ((flags & WIMLIB_EXTRACT_FLAG_NTFS)) {
 455         #ifndef WITH_NTFS_3G
 456                 ERROR("wimlib was compiled without support for NTFS-3g, so");
 457                 ERROR("we cannot extract a WIM image while preserving NTFS-");
 458                 ERROR("specific information");
 459         #endif
 460                 if (flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 461                         return WIMLIB_ERR_INVALID_PARAM;
 462                 if (getuid() != 0) {
 463                         ERROR("We are not root, but NTFS-3g requires root privileges to set arbitrary");
 464                         ERROR("security data on the NTFS filesystem.  Please run this program as root");
 465                         ERROR("if you want to extract a WIM image while preserving NTFS-specific");
 466                         ERROR("information.");
 467
 468                         return WIMLIB_ERR_NOT_ROOT;
 469                 }
 470         }
 471 }