wimlib.net Git - wimlib/blob - src/extract.c

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