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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 #include "wimlib_internal.h"
  28 #include "dentry.h"
  29 #include "lookup_table.h"
  30 #include "xml.h"
  31 #include <sys/stat.h>
  32 #include <fcntl.h>
  33 #include <unistd.h>
  34 #include <dirent.h>
  35 #include <string.h>
  36 #include <errno.h>
  37
  38 #ifdef WITH_NTFS_3G
  39 #include <ntfs-3g/volume.h>
  40 #include <ntfs-3g/security.h>
  41 #endif
  42
  43 /* Internal */
  44 #define WIMLIB_EXTRACT_FLAG_MULTI_IMAGE 0x80000000
  45
  46 static int extract_regular_file_linked(const struct dentry *dentry,
  47                                        const char *output_dir,
  48                                        const char *output_path,
  49                                        int extract_flags,
  50                                        struct lookup_table_entry *lte)
  51 {
  52         /* This mode overrides the normal hard-link extraction and
  53          * instead either symlinks or hardlinks *all* identical files in
  54          * the WIM, even if they are in a different image (in the case
  55          * of a multi-image extraction) */
  56
  57         wimlib_assert(lte->file_on_disk);
  58
  59
  60         if (extract_flags & WIMLIB_EXTRACT_FLAG_HARDLINK) {
  61                 if (link(lte->file_on_disk, output_path) != 0) {
  62                         ERROR_WITH_ERRNO("Failed to hard link "
  63                                          "`%s' to `%s'",
  64                                          output_path, lte->file_on_disk);
  65                         return WIMLIB_ERR_LINK;
  66                 }
  67         } else {
  68                 int num_path_components;
  69                 int num_output_dir_path_components;
  70                 size_t file_on_disk_len;
  71                 char *p;
  72                 const char *p2;
  73                 size_t i;
  74
  75                 wimlib_assert(extract_flags & WIMLIB_EXTRACT_FLAG_SYMLINK);
  76
  77                 num_path_components =
  78                         get_num_path_components(dentry->full_path_utf8) - 1;
  79                 num_output_dir_path_components =
  80                         get_num_path_components(output_dir);
  81
  82                 if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
  83                         num_path_components++;
  84                         num_output_dir_path_components--;
  85                 }
  86                 file_on_disk_len = strlen(lte->file_on_disk);
  87
  88                 char buf[file_on_disk_len + 3 * num_path_components + 1];
  89                 p = &buf[0];
  90
  91                 for (i = 0; i < num_path_components; i++) {
  92                         *p++ = '.';
  93                         *p++ = '.';
  94                         *p++ = '/';
  95                 }
  96                 p2 = lte->file_on_disk;
  97                 while (*p2 == '/')
  98                         p2++;
  99                 while (num_output_dir_path_components--)
 100                         p2 = path_next_part(p2, NULL);
 101                 strcpy(p, p2);
 102                 if (symlink(buf, output_path) != 0) {
 103                         ERROR_WITH_ERRNO("Failed to symlink `%s' to "
 104                                          "`%s'",
 105                                          buf, lte->file_on_disk);
 106                         return WIMLIB_ERR_LINK;
 107                 }
 108
 109         }
 110         return 0;
 111 }
 112
 113 static int extract_regular_file_unlinked(WIMStruct *w,
 114                                          struct dentry *dentry,
 115                                          const char *output_path,
 116                                          int extract_flags,
 117                                          struct lookup_table_entry *lte)
 118 {
 119         /* Normal mode of extraction.  Regular files and hard links are
 120          * extracted in the way that they appear in the WIM. */
 121
 122         int out_fd;
 123         const struct resource_entry *res_entry;
 124         int ret;
 125         const struct list_head *head = &dentry->link_group_list;
 126
 127         if (head->next != head) {
 128                 /* This dentry is one of a hard link set of at least 2 dentries.
 129                  * If one of the other dentries has already been extracted, make
 130                  * a hard link to the file corresponding to this
 131                  * already-extracted directory.  Otherwise, extract the
 132                  * file, and set the dentry->extracted_file field so that other
 133                  * dentries in the hard link group can link to it. */
 134                 struct dentry *other;
 135                 list_for_each_entry(other, head, link_group_list) {
 136                         if (other->extracted_file) {
 137                                 DEBUG("Extracting hard link `%s' => `%s'",
 138                                       output_path, other->extracted_file);
 139                                 if (link(other->extracted_file, output_path) != 0) {
 140                                         ERROR_WITH_ERRNO("Failed to hard link "
 141                                                          "`%s' to `%s'",
 142                                                          output_path,
 143                                                          other->extracted_file);
 144                                         return WIMLIB_ERR_LINK;
 145                                 }
 146                                 return 0;
 147                         }
 148                 }
 149                 FREE(dentry->extracted_file);
 150                 dentry->extracted_file = STRDUP(output_path);
 151                 if (!dentry->extracted_file) {
 152                         ERROR("Failed to allocate memory for filename");
 153                         return WIMLIB_ERR_NOMEM;
 154                 }
 155         }
 156
 157         /* Extract the contents of the file to @output_path. */
 158
 159         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 160         if (out_fd == -1) {
 161                 ERROR_WITH_ERRNO("Failed to open the file `%s' for writing",
 162                                  output_path);
 163                 return WIMLIB_ERR_OPEN;
 164         }
 165
 166         if (!lte) {
 167                 /* Empty file with no lookup table entry */
 168                 DEBUG("Empty file `%s'.", output_path);
 169                 ret = 0;
 170                 goto done;
 171         }
 172
 173
 174         res_entry = &lte->resource_entry;
 175
 176         ret = extract_resource_to_fd(w, res_entry, out_fd,
 177                                      res_entry->original_size);
 178
 179         if (ret != 0) {
 180                 ERROR("Failed to extract resource to `%s'", output_path);
 181                 goto done;
 182         }
 183
 184         if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
 185                 /* Mark the lookup table entry to indicate this file has been
 186                  * extracted. */
 187                 lte->out_refcnt++;
 188                 FREE(lte->file_on_disk);
 189                 lte->file_on_disk = STRDUP(output_path);
 190                 if (!lte->file_on_disk)
 191                         ret = WIMLIB_ERR_NOMEM;
 192         }
 193 done:
 194         if (close(out_fd) != 0) {
 195                 ERROR_WITH_ERRNO("Failed to close file `%s'", output_path);
 196                 ret = WIMLIB_ERR_WRITE;
 197         }
 198         return ret;
 199 }
 200
 201 /*
 202  * Extracts a regular file from the WIM archive.
 203  */
 204 static int extract_regular_file(WIMStruct *w,
 205                                 struct dentry *dentry,
 206                                 const char *output_dir,
 207                                 const char *output_path,
 208                                 int extract_flags)
 209 {
 210         struct lookup_table_entry *lte;
 211
 212         lte = __lookup_resource(w->lookup_table, dentry_hash(dentry));
 213
 214         if ((extract_flags & (WIMLIB_EXTRACT_FLAG_SYMLINK |
 215                               WIMLIB_EXTRACT_FLAG_HARDLINK)) && lte) {
 216                 if (lte->out_refcnt++ != 0)
 217                         return extract_regular_file_linked(dentry, output_dir,
 218                                                            output_path,
 219                                                            extract_flags, lte);
 220                 lte->file_on_disk = STRDUP(output_path);
 221                 if (!lte->file_on_disk)
 222                         return WIMLIB_ERR_NOMEM;
 223         }
 224
 225         return extract_regular_file_unlinked(w, dentry, output_path,
 226                                              extract_flags, lte);
 227
 228 }
 229
 230 static int extract_symlink(const struct dentry *dentry, const char *output_path,
 231                            const WIMStruct *w)
 232 {
 233         char target[4096];
 234         ssize_t ret = dentry_readlink(dentry, target, sizeof(target), w);
 235         if (ret <= 0) {
 236                 ERROR("Could not read the symbolic link from dentry `%s'",
 237                       dentry->full_path_utf8);
 238                 return WIMLIB_ERR_INVALID_DENTRY;
 239         }
 240         ret = symlink(target, output_path);
 241         if (ret != 0) {
 242                 ERROR_WITH_ERRNO("Failed to symlink `%s' to `%s'",
 243                                  output_path, target);
 244                 return WIMLIB_ERR_LINK;
 245         }
 246         return 0;
 247 }
 248
 249 /*
 250  * Extracts a directory from the WIM archive.
 251  *
 252  * @dentry:             The directory entry for the directory.
 253  * @output_path:        The path to which the directory is to be extracted to.
 254  * @return:             True on success, false on failure.
 255  */
 256 static int extract_directory(const char *output_path)
 257 {
 258         /* Compute the output path directory to the directory. */
 259         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0)
 260         {
 261                 switch (errno) {
 262                 case EEXIST: /* Already existing directory is OK */
 263                 case EACCES: /* We may have permissions to extract files inside
 264                                  the directory, but not for the directory
 265                                  itself. */
 266                         return 0;
 267                 default:
 268                         ERROR_WITH_ERRNO("Cannot create directory `%s'",
 269                                          output_path);
 270                         return WIMLIB_ERR_MKDIR;
 271                 }
 272         }
 273         return 0;
 274 }
 275
 276 struct extract_args {
 277         WIMStruct *w;
 278         int extract_flags;
 279         const char *output_dir;
 280 #ifdef WITH_NTFS_3G
 281         struct SECURITY_API *scapi;
 282 #endif
 283 };
 284
 285 /*
 286  * Extracts a file or directory from the WIM archive.  For use in
 287  * for_dentry_in_tree().
 288  *
 289  * @dentry:     The dentry to extract.
 290  * @arg:        A pointer to the WIMStruct for the WIM file.
 291  */
 292 static int extract_dentry(struct dentry *dentry, void *arg)
 293 {
 294         struct extract_args *args = arg;
 295         WIMStruct *w = args->w;
 296         int extract_flags = args->extract_flags;
 297         size_t len = strlen(args->output_dir);
 298         char output_path[len + dentry->full_path_utf8_len + 1];
 299         int ret = 0;
 300
 301         if (extract_flags & WIMLIB_EXTRACT_FLAG_VERBOSE)
 302                 puts(dentry->full_path_utf8);
 303
 304         memcpy(output_path, args->output_dir, len);
 305         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 306         output_path[len + dentry->full_path_utf8_len] = '\0';
 307
 308         if (dentry_is_symlink(dentry)) {
 309                 ret = extract_symlink(dentry, output_path, w);
 310         } else if (dentry_is_directory(dentry)) {
 311                 ret = extract_directory(output_path);
 312         } else {
 313                 ret = extract_regular_file(w, dentry, args->output_dir,
 314                                            output_path, extract_flags);
 315         }
 316         return ret;
 317 }
 318
 319
 320 static int extract_single_image(WIMStruct *w, int image,
 321                                 const char *output_dir, int extract_flags)
 322 {
 323         DEBUG("Extracting image %d", image);
 324
 325         int ret;
 326         ret = wimlib_select_image(w, image);
 327         if (ret != 0)
 328                 return ret;
 329
 330         struct extract_args args = {
 331                 .w = w,
 332                 .extract_flags = extract_flags,
 333                 .output_dir = output_dir,
 334         #ifdef WITH_NTFS_3G
 335                 .scapi = NULL
 336         #endif
 337         };
 338
 339         return for_dentry_in_tree(wim_root_dentry(w), extract_dentry, &args);
 340 }
 341
 342
 343 /* Extracts all images from the WIM to @output_dir, with the images placed in
 344  * subdirectories named by their image names. */
 345 static int extract_all_images(WIMStruct *w, const char *output_dir,
 346                               int extract_flags)
 347 {
 348         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 349         size_t output_path_len = strlen(output_dir);
 350         char buf[output_path_len + 1 + image_name_max_len + 1];
 351         int ret;
 352         int image;
 353         const char *image_name;
 354
 355         DEBUG("Attempting to extract all images from `%s'", w->filename);
 356
 357         ret = extract_directory(output_dir);
 358         if (ret != 0)
 359                 return ret;
 360
 361         memcpy(buf, output_dir, output_path_len);
 362         buf[output_path_len] = '/';
 363         for (image = 1; image <= w->hdr.image_count; image++) {
 364
 365                 image_name = wimlib_get_image_name(w, image);
 366                 if (*image_name) {
 367                         strcpy(buf + output_path_len + 1, image_name);
 368                 } else {
 369                         /* Image name is empty. Use image number instead */
 370                         sprintf(buf + output_path_len + 1, "%d", image);
 371                 }
 372                 ret = extract_single_image(w, image, buf, extract_flags);
 373                 if (ret != 0)
 374                         goto done;
 375         }
 376 done:
 377         /* Restore original output directory */
 378         buf[output_path_len + 1] = '\0';
 379         return 0;
 380 }
 381
 382 /* Extracts a single image or all images from a WIM file. */
 383 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image,
 384                                    const char *output_dir, int flags)
 385 {
 386         int ret;
 387         if (!output_dir)
 388                 return WIMLIB_ERR_INVALID_PARAM;
 389         if ((flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 390                         == (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 391                 return WIMLIB_ERR_INVALID_PARAM;
 392
 393         if (image == WIM_ALL_IMAGES) {
 394                 flags |= WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 395                 for_lookup_table_entry(w->lookup_table, zero_out_refcnts, NULL);
 396         } else {
 397                 flags &= ~WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 398         }
 399
 400         if ((flags & WIMLIB_EXTRACT_FLAG_NTFS)) {
 401         #ifdef WITH_NTFS_3G
 402                 unsigned long mnt_flags;
 403                 ret = ntfs_check_if_mounted(output_dir, &mnt_flags);
 404                 if (ret != 0) {
 405                         ERROR_WITH_ERRNO("NTFS-3g: Cannot determine if `%s' "
 406                                          "is mounted", output_dir);
 407                         return WIMLIB_ERR_NTFS_3G;
 408                 }
 409                 if (!(mnt_flags & NTFS_MF_MOUNTED)) {
 410                         ERROR("NTFS-3g: Filesystem on `%s' is not mounted ",
 411                               output_dir);
 412                         return WIMLIB_ERR_NTFS_3G;
 413                 }
 414                 if (mnt_flags & NTFS_MF_READONLY) {
 415                         ERROR("NTFS-3g: Filesystem on `%s' is mounted "
 416                               "read-only", output_dir);
 417                         return WIMLIB_ERR_NTFS_3G;
 418                 }
 419         #else
 420                 ERROR("wimlib was compiled without support for NTFS-3g, so");
 421                 ERROR("we cannot extract a WIM image while preserving NTFS-");
 422                 ERROR("specific information");
 423                 return WIMLIB_ERR_UNSUPPORTED;
 424         #endif
 425         }
 426         if (image == WIM_ALL_IMAGES)
 427                 ret = extract_all_images(w, output_dir, flags);
 428         else
 429                 ret = extract_single_image(w, image, output_dir, flags);
 430         return ret;
 431
 432 }