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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 "timestamp.h"
  31 #include "xml.h"
  32 #include <sys/stat.h>
  33 #include <fcntl.h>
  34 #include <unistd.h>
  35 #include <dirent.h>
  36 #include <string.h>
  37 #include <errno.h>
  38
  39 #ifdef WITH_NTFS_3G
  40 #include <ntfs-3g/volume.h>
  41 #include <ntfs-3g/security.h>
  42 #endif
  43
  44 /* Internal */
  45 #define WIMLIB_EXTRACT_FLAG_MULTI_IMAGE 0x80000000
  46
  47 static int extract_regular_file_linked(const struct dentry *dentry,
  48                                        const char *output_dir,
  49                                        const char *output_path,
  50                                        int extract_flags,
  51                                        struct lookup_table_entry *lte)
  52 {
  53         /* This mode overrides the normal hard-link extraction and
  54          * instead either symlinks or hardlinks *all* identical files in
  55          * the WIM, even if they are in a different image (in the case
  56          * of a multi-image extraction) */
  57
  58         wimlib_assert(lte->file_on_disk);
  59
  60
  61         if (extract_flags & WIMLIB_EXTRACT_FLAG_HARDLINK) {
  62                 if (link(lte->file_on_disk, output_path) != 0) {
  63                         ERROR_WITH_ERRNO("Failed to hard link "
  64                                          "`%s' to `%s'",
  65                                          output_path, lte->file_on_disk);
  66                         return WIMLIB_ERR_LINK;
  67                 }
  68         } else {
  69                 int num_path_components;
  70                 int num_output_dir_path_components;
  71                 size_t file_on_disk_len;
  72                 char *p;
  73                 const char *p2;
  74                 size_t i;
  75
  76                 wimlib_assert(extract_flags & WIMLIB_EXTRACT_FLAG_SYMLINK);
  77
  78                 num_path_components =
  79                         get_num_path_components(dentry->full_path_utf8) - 1;
  80                 num_output_dir_path_components =
  81                         get_num_path_components(output_dir);
  82
  83                 if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
  84                         num_path_components++;
  85                         num_output_dir_path_components--;
  86                 }
  87                 file_on_disk_len = strlen(lte->file_on_disk);
  88
  89                 char buf[file_on_disk_len + 3 * num_path_components + 1];
  90                 p = &buf[0];
  91
  92                 for (i = 0; i < num_path_components; i++) {
  93                         *p++ = '.';
  94                         *p++ = '.';
  95                         *p++ = '/';
  96                 }
  97                 p2 = lte->file_on_disk;
  98                 while (*p2 == '/')
  99                         p2++;
 100                 while (num_output_dir_path_components--)
 101                         p2 = path_next_part(p2, NULL);
 102                 strcpy(p, p2);
 103                 if (symlink(buf, output_path) != 0) {
 104                         ERROR_WITH_ERRNO("Failed to symlink `%s' to "
 105                                          "`%s'",
 106                                          buf, lte->file_on_disk);
 107                         return WIMLIB_ERR_LINK;
 108                 }
 109
 110         }
 111         return 0;
 112 }
 113
 114 static int extract_regular_file_unlinked(WIMStruct *w,
 115                                          struct dentry *dentry,
 116                                          const char *output_path,
 117                                          int extract_flags,
 118                                          struct lookup_table_entry *lte)
 119 {
 120         /* Normal mode of extraction.  Regular files and hard links are
 121          * extracted in the way that they appear in the WIM. */
 122
 123         int out_fd;
 124         const struct resource_entry *res_entry;
 125         int ret;
 126         const struct list_head *head = &dentry->link_group_list;
 127
 128         if (head->next != head) {
 129                 /* This dentry is one of a hard link set of at least 2 dentries.
 130                  * If one of the other dentries has already been extracted, make
 131                  * a hard link to the file corresponding to this
 132                  * already-extracted directory.  Otherwise, extract the
 133                  * file, and set the dentry->extracted_file field so that other
 134                  * dentries in the hard link group can link to it. */
 135                 struct dentry *other;
 136                 list_for_each_entry(other, head, link_group_list) {
 137                         if (other->extracted_file) {
 138                                 DEBUG("Extracting hard link `%s' => `%s'",
 139                                       output_path, other->extracted_file);
 140                                 if (link(other->extracted_file, output_path) != 0) {
 141                                         ERROR_WITH_ERRNO("Failed to hard link "
 142                                                          "`%s' to `%s'",
 143                                                          output_path,
 144                                                          other->extracted_file);
 145                                         return WIMLIB_ERR_LINK;
 146                                 }
 147                                 return 0;
 148                         }
 149                 }
 150                 FREE(dentry->extracted_file);
 151                 dentry->extracted_file = STRDUP(output_path);
 152                 if (!dentry->extracted_file) {
 153                         ERROR("Failed to allocate memory for filename");
 154                         return WIMLIB_ERR_NOMEM;
 155                 }
 156         }
 157
 158         /* Extract the contents of the file to @output_path. */
 159
 160         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 161         if (out_fd == -1) {
 162                 ERROR_WITH_ERRNO("Failed to open the file `%s' for writing",
 163                                  output_path);
 164                 return WIMLIB_ERR_OPEN;
 165         }
 166
 167         if (!lte) {
 168                 /* Empty file with no lookup table entry */
 169                 DEBUG("Empty file `%s'.", output_path);
 170                 ret = 0;
 171                 goto done;
 172         }
 173
 174
 175         res_entry = &lte->resource_entry;
 176
 177         ret = extract_resource_to_fd(w, res_entry, out_fd,
 178                                      res_entry->original_size);
 179
 180         if (ret != 0) {
 181                 ERROR("Failed to extract resource to `%s'", output_path);
 182                 goto done;
 183         }
 184
 185         if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
 186                 /* Mark the lookup table entry to indicate this file has been
 187                  * extracted. */
 188                 lte->out_refcnt++;
 189                 FREE(lte->file_on_disk);
 190                 lte->file_on_disk = STRDUP(output_path);
 191                 if (!lte->file_on_disk)
 192                         ret = WIMLIB_ERR_NOMEM;
 193         }
 194 done:
 195         if (close(out_fd) != 0) {
 196                 ERROR_WITH_ERRNO("Failed to close file `%s'", output_path);
 197                 ret = WIMLIB_ERR_WRITE;
 198         }
 199         return ret;
 200 }
 201
 202 /*
 203  * Extracts a regular file from the WIM archive.
 204  */
 205 static int extract_regular_file(WIMStruct *w,
 206                                 struct dentry *dentry,
 207                                 const char *output_dir,
 208                                 const char *output_path,
 209                                 int extract_flags)
 210 {
 211         struct lookup_table_entry *lte;
 212
 213         lte = dentry_first_lte(dentry, w->lookup_table);
 214
 215         if ((extract_flags & (WIMLIB_EXTRACT_FLAG_SYMLINK |
 216                               WIMLIB_EXTRACT_FLAG_HARDLINK)) && lte) {
 217                 if (lte->out_refcnt++ != 0)
 218                         return extract_regular_file_linked(dentry, output_dir,
 219                                                            output_path,
 220                                                            extract_flags, lte);
 221                 lte->file_on_disk = STRDUP(output_path);
 222                 if (!lte->file_on_disk)
 223                         return WIMLIB_ERR_NOMEM;
 224         }
 225
 226         return extract_regular_file_unlinked(w, dentry, output_path,
 227                                              extract_flags, lte);
 228
 229 }
 230
 231 static int extract_symlink(const struct dentry *dentry, const char *output_path,
 232                            const WIMStruct *w)
 233 {
 234         char target[4096];
 235         ssize_t ret = dentry_readlink(dentry, target, sizeof(target), w);
 236         if (ret <= 0) {
 237                 ERROR("Could not read the symbolic link from dentry `%s'",
 238                       dentry->full_path_utf8);
 239                 return WIMLIB_ERR_INVALID_DENTRY;
 240         }
 241         ret = symlink(target, output_path);
 242         if (ret != 0) {
 243                 ERROR_WITH_ERRNO("Failed to symlink `%s' to `%s'",
 244                                  output_path, target);
 245                 return WIMLIB_ERR_LINK;
 246         }
 247         return 0;
 248 }
 249
 250 /*
 251  * Extracts a directory from the WIM archive.
 252  *
 253  * @dentry:             The directory entry for the directory.
 254  * @output_path:        The path to which the directory is to be extracted to.
 255  * @return:             True on success, false on failure.
 256  */
 257 static int extract_directory(const char *output_path)
 258 {
 259         /* Compute the output path directory to the directory. */
 260         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0)
 261         {
 262                 switch (errno) {
 263                 case EEXIST: /* Already existing directory is OK */
 264                 case EACCES: /* We may have permissions to extract files inside
 265                                  the directory, but not for the directory
 266                                  itself. */
 267                         return 0;
 268                 default:
 269                         ERROR_WITH_ERRNO("Cannot create directory `%s'",
 270                                          output_path);
 271                         return WIMLIB_ERR_MKDIR;
 272                 }
 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);
 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         struct timeval tv[2];
 319         wim_timestamp_to_timeval(dentry->last_access_time, &tv[0]);
 320         wim_timestamp_to_timeval(dentry->last_write_time, &tv[1]);
 321         if (lutimes(output_path, tv) != 0) {
 322                 WARNING("Failed to set timestamp on file `%s': %s",
 323                         output_path, strerror(errno));
 324         }
 325         return 0;
 326 }
 327
 328
 329 static int extract_single_image(WIMStruct *w, int image,
 330                                 const char *output_dir, int extract_flags)
 331 {
 332         DEBUG("Extracting image %d", image);
 333
 334         int ret;
 335         ret = wimlib_select_image(w, image);
 336         if (ret != 0)
 337                 return ret;
 338
 339         struct extract_args args = {
 340                 .w = w,
 341                 .extract_flags = extract_flags,
 342                 .output_dir = output_dir,
 343         #ifdef WITH_NTFS_3G
 344                 .scapi = NULL
 345         #endif
 346         };
 347
 348         return for_dentry_in_tree(wim_root_dentry(w), extract_dentry, &args);
 349 }
 350
 351
 352 /* Extracts all images from the WIM to @output_dir, with the images placed in
 353  * subdirectories named by their image names. */
 354 static int extract_all_images(WIMStruct *w, const char *output_dir,
 355                               int extract_flags)
 356 {
 357         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 358         size_t output_path_len = strlen(output_dir);
 359         char buf[output_path_len + 1 + image_name_max_len + 1];
 360         int ret;
 361         int image;
 362         const char *image_name;
 363
 364         DEBUG("Attempting to extract all images from `%s'", w->filename);
 365
 366         ret = extract_directory(output_dir);
 367         if (ret != 0)
 368                 return ret;
 369
 370         memcpy(buf, output_dir, output_path_len);
 371         buf[output_path_len] = '/';
 372         for (image = 1; image <= w->hdr.image_count; image++) {
 373
 374                 image_name = wimlib_get_image_name(w, image);
 375                 if (*image_name) {
 376                         strcpy(buf + output_path_len + 1, image_name);
 377                 } else {
 378                         /* Image name is empty. Use image number instead */
 379                         sprintf(buf + output_path_len + 1, "%d", image);
 380                 }
 381                 ret = extract_single_image(w, image, buf, extract_flags);
 382                 if (ret != 0)
 383                         goto done;
 384         }
 385 done:
 386         /* Restore original output directory */
 387         buf[output_path_len + 1] = '\0';
 388         return 0;
 389 }
 390
 391 /* Extracts a single image or all images from a WIM file. */
 392 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image,
 393                                    const char *output_dir, int flags)
 394 {
 395
 396         if (!output_dir)
 397                 return WIMLIB_ERR_INVALID_PARAM;
 398
 399         if ((flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 400                         == (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 401                 return WIMLIB_ERR_INVALID_PARAM;
 402
 403         if ((flags & WIMLIB_EXTRACT_FLAG_NTFS)) {
 404         #ifdef WITH_NTFS_3G
 405                 unsigned long mnt_flags;
 406                 int ret = ntfs_check_if_mounted(output_dir, &mnt_flags);
 407                 if (ret != 0) {
 408                         ERROR_WITH_ERRNO("NTFS-3g: Cannot determine if `%s' "
 409                                          "is mounted", output_dir);
 410                         return WIMLIB_ERR_NTFS_3G;
 411                 }
 412                 if (!(mnt_flags & NTFS_MF_MOUNTED)) {
 413                         ERROR("NTFS-3g: Filesystem on `%s' is not mounted ",
 414                               output_dir);
 415                         return WIMLIB_ERR_NTFS_3G;
 416                 }
 417                 if (mnt_flags & NTFS_MF_READONLY) {
 418                         ERROR("NTFS-3g: Filesystem on `%s' is mounted "
 419                               "read-only", output_dir);
 420                         return WIMLIB_ERR_NTFS_3G;
 421                 }
 422         #else
 423                 ERROR("wimlib was compiled without support for NTFS-3g, so");
 424                 ERROR("we cannot extract a WIM image while preserving NTFS-");
 425                 ERROR("specific information");
 426                 return WIMLIB_ERR_UNSUPPORTED;
 427         #endif
 428         }
 429
 430         for_lookup_table_entry(w->lookup_table, zero_out_refcnts, NULL);
 431
 432         if (image == WIM_ALL_IMAGES) {
 433                 flags |= WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 434                 return extract_all_images(w, output_dir, flags);
 435         } else {
 436                 flags &= ~WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 437                 return extract_single_image(w, image, output_dir, flags);
 438         }
 439
 440 }