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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 /* 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         wimlib_assert(lte->extracted_file);
  57
  58         if (extract_flags & WIMLIB_EXTRACT_FLAG_HARDLINK) {
  59                 if (link(lte->extracted_file, output_path) != 0) {
  60                         ERROR_WITH_ERRNO("Failed to hard link "
  61                                          "`%s' to `%s'",
  62                                          output_path, lte->extracted_file);
  63                         return WIMLIB_ERR_LINK;
  64                 }
  65         } else {
  66                 int num_path_components;
  67                 int num_output_dir_path_components;
  68                 size_t extracted_file_len;
  69                 char *p;
  70                 const char *p2;
  71                 size_t i;
  72
  73                 wimlib_assert(extract_flags & WIMLIB_EXTRACT_FLAG_SYMLINK);
  74
  75                 num_path_components =
  76                         get_num_path_components(dentry->full_path_utf8) - 1;
  77                 num_output_dir_path_components =
  78                         get_num_path_components(output_dir);
  79
  80                 if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
  81                         num_path_components++;
  82                         num_output_dir_path_components--;
  83                 }
  84                 extracted_file_len = strlen(lte->extracted_file);
  85
  86                 char buf[extracted_file_len + 3 * num_path_components + 1];
  87                 p = &buf[0];
  88
  89                 for (i = 0; i < num_path_components; i++) {
  90                         *p++ = '.';
  91                         *p++ = '.';
  92                         *p++ = '/';
  93                 }
  94                 p2 = lte->extracted_file;
  95                 while (*p2 == '/')
  96                         p2++;
  97                 while (num_output_dir_path_components--)
  98                         p2 = path_next_part(p2, NULL);
  99                 strcpy(p, p2);
 100                 if (symlink(buf, output_path) != 0) {
 101                         ERROR_WITH_ERRNO("Failed to symlink `%s' to "
 102                                          "`%s'",
 103                                          buf, lte->extracted_file);
 104                         return WIMLIB_ERR_LINK;
 105                 }
 106
 107         }
 108         return 0;
 109 }
 110
 111 static int extract_regular_file_unlinked(WIMStruct *w,
 112                                          struct dentry *dentry,
 113                                          const char *output_path,
 114                                          int extract_flags,
 115                                          struct lookup_table_entry *lte)
 116 {
 117         /* Normal mode of extraction.  Regular files and hard links are
 118          * extracted in the way that they appear in the WIM. */
 119
 120         int out_fd;
 121         const struct resource_entry *res_entry;
 122         int ret;
 123         const struct list_head *head = &dentry->link_group_list;
 124
 125         if (head->next != head &&
 126              !(extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE))
 127         {
 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         ret = extract_full_wim_resource_to_fd(lte, out_fd);
 174         if (ret != 0) {
 175                 ERROR("Failed to extract resource to `%s'", output_path);
 176                 goto done;
 177         }
 178
 179 done:
 180         if (close(out_fd) != 0) {
 181                 ERROR_WITH_ERRNO("Failed to close file `%s'", output_path);
 182                 ret = WIMLIB_ERR_WRITE;
 183         }
 184         return ret;
 185 }
 186
 187 /*
 188  * Extracts a regular file from the WIM archive.
 189  */
 190 static int extract_regular_file(WIMStruct *w,
 191                                 struct dentry *dentry,
 192                                 const char *output_dir,
 193                                 const char *output_path,
 194                                 int extract_flags)
 195 {
 196         struct lookup_table_entry *lte;
 197
 198         lte = dentry_first_lte(dentry, w->lookup_table);
 199
 200         if ((extract_flags & (WIMLIB_EXTRACT_FLAG_SYMLINK |
 201                               WIMLIB_EXTRACT_FLAG_HARDLINK)) && lte) {
 202                 if (++lte->out_refcnt != 1)
 203                         return extract_regular_file_linked(dentry, output_dir,
 204                                                            output_path,
 205                                                            extract_flags, lte);
 206                 lte->extracted_file = STRDUP(output_path);
 207                 if (!lte->extracted_file)
 208                         return WIMLIB_ERR_NOMEM;
 209         }
 210
 211         return extract_regular_file_unlinked(w, dentry, output_path,
 212                                              extract_flags, lte);
 213
 214 }
 215
 216 static int extract_symlink(const struct dentry *dentry, const char *output_path,
 217                            const WIMStruct *w)
 218 {
 219         char target[4096];
 220         ssize_t ret = dentry_readlink(dentry, target, sizeof(target), w);
 221         if (ret <= 0) {
 222                 ERROR("Could not read the symbolic link from dentry `%s'",
 223                       dentry->full_path_utf8);
 224                 return WIMLIB_ERR_INVALID_DENTRY;
 225         }
 226         ret = symlink(target, output_path);
 227         if (ret != 0) {
 228                 ERROR_WITH_ERRNO("Failed to symlink `%s' to `%s'",
 229                                  output_path, target);
 230                 return WIMLIB_ERR_LINK;
 231         }
 232         return 0;
 233 }
 234
 235 /*
 236  * Extracts a directory from the WIM archive.
 237  *
 238  * @dentry:             The directory entry for the directory.
 239  * @output_path:        The path to which the directory is to be extracted to.
 240  * @return:             True on success, false on failure.
 241  */
 242 static int extract_directory(const char *output_path, bool is_root)
 243 {
 244         int ret;
 245         struct stat stbuf;
 246         ret = stat(output_path, &stbuf);
 247         if (ret == 0) {
 248                 if (S_ISDIR(stbuf.st_mode)) {
 249                         if (!is_root)
 250                                 WARNING("`%s' already exists", output_path);
 251                         return 0;
 252                 } else {
 253                         ERROR("`%s' is not a directory", output_path);
 254                         return WIMLIB_ERR_MKDIR;
 255                 }
 256         } else {
 257                 if (errno != ENOENT) {
 258                         ERROR_WITH_ERRNO("Failed to stat `%s'", output_path);
 259                         return WIMLIB_ERR_STAT;
 260                 }
 261         }
 262         /* Compute the output path directory to the directory. */
 263         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP |
 264                                S_IROTH | S_IXOTH) != 0) {
 265                 ERROR_WITH_ERRNO("Cannot create directory `%s'",
 266                                  output_path);
 267                 return WIMLIB_ERR_MKDIR;
 268         }
 269         return 0;
 270 }
 271
 272 struct extract_args {
 273         WIMStruct *w;
 274         int extract_flags;
 275         const char *output_dir;
 276 #ifdef WITH_NTFS_3G
 277         struct SECURITY_API *scapi;
 278 #endif
 279 };
 280
 281 /*
 282  * Extracts a file, directory, or symbolic link from the WIM archive.  For use
 283  * in for_dentry_in_tree().
 284  */
 285 static int extract_dentry(struct dentry *dentry, void *arg)
 286 {
 287         struct extract_args *args = arg;
 288         WIMStruct *w = args->w;
 289         int extract_flags = args->extract_flags;
 290         size_t len = strlen(args->output_dir);
 291         char output_path[len + dentry->full_path_utf8_len + 1];
 292         int ret;
 293
 294         if (extract_flags & WIMLIB_EXTRACT_FLAG_VERBOSE) {
 295                 wimlib_assert(dentry->full_path_utf8);
 296                 puts(dentry->full_path_utf8);
 297         }
 298
 299         memcpy(output_path, args->output_dir, len);
 300         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 301         output_path[len + dentry->full_path_utf8_len] = '\0';
 302
 303         if (dentry_is_symlink(dentry))
 304                 ret = extract_symlink(dentry, output_path, w);
 305         else if (dentry_is_directory(dentry))
 306                 ret = extract_directory(output_path, dentry_is_root(dentry));
 307         else
 308                 ret = extract_regular_file(w, dentry, args->output_dir,
 309                                             output_path, extract_flags);
 310         if (ret != 0)
 311                 return ret;
 312
 313         return 0;
 314 }
 315
 316 /* Apply timestamp to extracted file */
 317 static int apply_dentry_timestamps(struct dentry *dentry, void *arg)
 318 {
 319         struct extract_args *args = arg;
 320         size_t len = strlen(args->output_dir);
 321         char output_path[len + dentry->full_path_utf8_len + 1];
 322
 323         memcpy(output_path, args->output_dir, len);
 324         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 325         output_path[len + dentry->full_path_utf8_len] = '\0';
 326
 327         struct timeval tv[2];
 328         wim_timestamp_to_timeval(dentry->last_access_time, &tv[0]);
 329         wim_timestamp_to_timeval(dentry->last_write_time, &tv[1]);
 330         if (lutimes(output_path, tv) != 0) {
 331                 WARNING("Failed to set timestamp on file `%s': %s",
 332                         output_path, strerror(errno));
 333         }
 334         return 0;
 335 }
 336
 337
 338 static int extract_single_image(WIMStruct *w, int image,
 339                                 const char *output_dir, int extract_flags)
 340 {
 341         DEBUG("Extracting image %d", image);
 342
 343         int ret;
 344         ret = wimlib_select_image(w, image);
 345         if (ret != 0)
 346                 return ret;
 347
 348         struct extract_args args = {
 349                 .w = w,
 350                 .extract_flags = extract_flags,
 351                 .output_dir = output_dir,
 352         #ifdef WITH_NTFS_3G
 353                 .scapi = NULL
 354         #endif
 355         };
 356
 357         ret = for_dentry_in_tree(wim_root_dentry(w), extract_dentry, &args);
 358         if (ret != 0)
 359                 return ret;
 360         return for_dentry_in_tree_depth(wim_root_dentry(w),
 361                                         apply_dentry_timestamps, &args);
 362
 363 }
 364
 365
 366 /* Extracts all images from the WIM to @output_dir, with the images placed in
 367  * subdirectories named by their image names. */
 368 static int extract_all_images(WIMStruct *w, const char *output_dir,
 369                               int extract_flags)
 370 {
 371         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 372         size_t output_path_len = strlen(output_dir);
 373         char buf[output_path_len + 1 + image_name_max_len + 1];
 374         int ret;
 375         int image;
 376         const char *image_name;
 377
 378         DEBUG("Attempting to extract all images from `%s'", w->filename);
 379
 380         ret = extract_directory(output_dir, true);
 381         if (ret != 0)
 382                 return ret;
 383
 384         memcpy(buf, output_dir, output_path_len);
 385         buf[output_path_len] = '/';
 386         for (image = 1; image <= w->hdr.image_count; image++) {
 387
 388                 image_name = wimlib_get_image_name(w, image);
 389                 if (*image_name) {
 390                         strcpy(buf + output_path_len + 1, image_name);
 391                 } else {
 392                         /* Image name is empty. Use image number instead */
 393                         sprintf(buf + output_path_len + 1, "%d", image);
 394                 }
 395                 ret = extract_single_image(w, image, buf, extract_flags);
 396                 if (ret != 0)
 397                         goto done;
 398         }
 399 done:
 400         /* Restore original output directory */
 401         buf[output_path_len + 1] = '\0';
 402         return 0;
 403 }
 404
 405 /* Extracts a single image or all images from a WIM file. */
 406 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image,
 407                                    const char *output_dir, int flags)
 408 {
 409         if (!output_dir)
 410                 return WIMLIB_ERR_INVALID_PARAM;
 411
 412         if ((flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 413                         == (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 414                 return WIMLIB_ERR_INVALID_PARAM;
 415
 416         for_lookup_table_entry(w->lookup_table, zero_out_refcnts, NULL);
 417
 418         if (image == WIM_ALL_IMAGES) {
 419                 flags |= WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 420                 return extract_all_images(w, output_dir, flags);
 421         } else {
 422                 flags &= ~WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 423                 return extract_single_image(w, image, output_dir, flags);
 424         }
 425
 426 }