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