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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 #endif
  41
  42 /* Sets and creates the directory to which files are to be extracted when
  43  * extracting files from the WIM. */
  44 static int set_output_dir(WIMStruct *w, const char *dir)
  45 {
  46         char *p;
  47         DEBUG("Setting output directory to `%s'", dir);
  48
  49         p = STRDUP(dir);
  50         if (!p) {
  51                 ERROR("Out of memory");
  52                 return WIMLIB_ERR_NOMEM;
  53         }
  54
  55         if (mkdir(dir, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0) {
  56                 if (errno == EEXIST) {
  57                         DEBUG("`%s' already exists", dir);
  58                         goto done;
  59                 }
  60                 ERROR_WITH_ERRNO("Cannot create directory `%s'", dir);
  61                 FREE(p);
  62                 return WIMLIB_ERR_MKDIR;
  63         } else {
  64                 DEBUG("Created directory `%s'", dir);
  65         }
  66 done:
  67         FREE(w->output_dir);
  68         w->output_dir = p;
  69         return 0;
  70 }
  71
  72 /*
  73  * Extracts a regular file from the WIM archive.
  74  *
  75  * @dentry:             The directory entry for the file, which must be a
  76  *                              regular file.
  77  * @output_path:        The path to which the file is to be extracted.
  78  * @lookup_table:       The lookup table for the WIM file.
  79  * @wim_fp:             The FILE* for the WIM, opened for reading.
  80  * @wim_ctype:          The type of compression used in the WIM.
  81  * @link_type:          One of WIM_LINK_TYPE_*; specifies what to do with
  82  *                      files that are hard-linked inside the WIM.
  83  * @is_multi_image_extraction:
  84  *                      True if the image currently being extracted is just one
  85  *                      image of a multi-image extraction.  This is needed so
  86  *                      that cross-image symbolic links can be created
  87  *                      correctly.
  88  */
  89 static int extract_regular_file(WIMStruct *w,
  90                                 const struct dentry *dentry,
  91                                 const char *output_path)
  92 {
  93         struct lookup_table_entry *lte;
  94         int ret;
  95         int out_fd;
  96         const struct resource_entry *res_entry;
  97
  98         lte = lookup_resource(w->lookup_table, dentry->hash);
  99
 100         /* If we already extracted the same file or a hard link copy of it, we
 101          * may be able to simply create a link.  The exact action is specified
 102          * by the current @link_type. */
 103         if ((w->extract_flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK)) &&
 104               lte && lte->out_refcnt != 0)
 105         {
 106                 wimlib_assert(lte->file_on_disk);
 107
 108                 if (w->extract_flags & WIMLIB_EXTRACT_FLAG_HARDLINK) {
 109                         if (link(lte->file_on_disk, output_path) != 0) {
 110                                 ERROR_WITH_ERRNO("Failed to hard link "
 111                                                  "`%s' to `%s'",
 112                                                  output_path, lte->file_on_disk);
 113                                 return WIMLIB_ERR_LINK;
 114                         }
 115                 } else {
 116                         int num_path_components;
 117                         int num_output_dir_path_components;
 118                         size_t file_on_disk_len;
 119                         char *p;
 120                         const char *p2;
 121                         size_t i;
 122
 123                         num_path_components =
 124                                 get_num_path_components(dentry->full_path_utf8) - 1;
 125                         num_output_dir_path_components =
 126                                 get_num_path_components(w->output_dir);
 127
 128                         if (w->is_multi_image_extraction) {
 129                                 num_path_components++;
 130                                 num_output_dir_path_components--;
 131                         }
 132                         file_on_disk_len = strlen(lte->file_on_disk);
 133
 134                         char buf[file_on_disk_len + 3 * num_path_components + 1];
 135                         p = &buf[0];
 136
 137                         for (i = 0; i < num_path_components; i++) {
 138                                 *p++ = '.';
 139                                 *p++ = '.';
 140                                 *p++ = '/';
 141                         }
 142                         p2 = lte->file_on_disk;
 143                         while (*p2 == '/')
 144                                 p2++;
 145                         while (num_output_dir_path_components--)
 146                                 p2 = path_next_part(p2, NULL);
 147                         strcpy(p, p2);
 148                         if (symlink(buf, output_path) != 0) {
 149                                 ERROR_WITH_ERRNO("Failed to symlink `%s' to "
 150                                                  "`%s'",
 151                                                  buf, lte->file_on_disk);
 152                                 return WIMLIB_ERR_LINK;
 153                         }
 154
 155                 }
 156                 return 0;
 157         }
 158
 159         /* Otherwise, we must actually extract the file contents. */
 160
 161         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 162         if (out_fd == -1) {
 163                 ERROR_WITH_ERRNO("Failed to open the file `%s' for writing",
 164                                  output_path);
 165                 return WIMLIB_ERR_OPEN;
 166         }
 167
 168         /* Extract empty file, with no lookup table entry... */
 169         if (!lte) {
 170                 DEBUG("Empty file `%s'.", output_path);
 171                 ret = 0;
 172                 goto done;
 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         /* Mark the lookup table entry to indicate this file has been extracted. */
 186         lte->out_refcnt++;
 187         FREE(lte->file_on_disk);
 188         lte->file_on_disk = STRDUP(output_path);
 189         if (lte->file_on_disk)
 190                 ret = 0;
 191         else
 192                 ret = WIMLIB_ERR_NOMEM;
 193 done:
 194         close(out_fd);
 195         return ret;
 196 }
 197
 198 /*
 199  * Extracts a directory from the WIM archive.
 200  *
 201  * @dentry:             The directory entry for the directory.
 202  * @output_path:        The path to which the directory is to be extracted to.
 203  * @return:             True on success, false on failure.
 204  */
 205 static int extract_directory(struct dentry *dentry, const char *output_path)
 206 {
 207         /* Compute the output path directory to the directory. */
 208         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0)
 209         {
 210                 switch (errno) {
 211                 case EEXIST: /* Already existing directory is OK */
 212                 case EACCES: /* We may have permissions to extract files inside
 213                                  the directory, but not for the directory
 214                                  itself. */
 215                         return 0;
 216                 default:
 217                         ERROR_WITH_ERRNO("Cannot create directory `%s'",
 218                                          output_path);
 219                         return WIMLIB_ERR_MKDIR;
 220                 }
 221         }
 222         return 0;
 223 }
 224
 225
 226 /*
 227  * Extracts a file or directory from the WIM archive.  For use in
 228  * for_dentry_in_tree().
 229  *
 230  * @dentry:     The dentry to extract.
 231  * @arg:        A pointer to the WIMStruct for the WIM file.
 232  */
 233 static int extract_regular_file_or_directory(struct dentry *dentry, void *arg)
 234 {
 235         WIMStruct *w = (WIMStruct*)arg;
 236         size_t len = strlen(w->output_dir);
 237         char output_path[len + dentry->full_path_utf8_len + 1];
 238
 239         if (w->extract_flags & WIMLIB_EXTRACT_FLAG_VERBOSE)
 240                 puts(dentry->full_path_utf8);
 241
 242         memcpy(output_path, w->output_dir, len);
 243         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 244         output_path[len + dentry->full_path_utf8_len] = '\0';
 245
 246         if (dentry_is_regular_file(dentry)) {
 247                 return extract_regular_file(w, dentry, output_path);
 248         } else {
 249                 if (dentry_is_root(dentry)) /* Root doesn't need to be extracted. */
 250                         return 0;
 251                 else
 252                         return extract_directory(dentry, output_path);
 253         }
 254 }
 255
 256 static int extract_single_image(WIMStruct *w, int image)
 257 {
 258         DEBUG("Extracting image %d", image);
 259
 260         int ret;
 261         ret = wimlib_select_image(w, image);
 262         if (ret != 0)
 263                 return ret;
 264
 265         return for_dentry_in_tree(wim_root_dentry(w),
 266                                   extract_regular_file_or_directory, w);
 267 }
 268
 269
 270 /* Extracts all images from the WIM to w->output_dir, with the images placed in
 271  * subdirectories named by their image names. */
 272 static int extract_all_images(WIMStruct *w)
 273 {
 274         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 275         size_t output_path_len = strlen(w->output_dir);
 276         char buf[output_path_len + 1 + image_name_max_len + 1];
 277         int ret;
 278         int image;
 279         const char *image_name;
 280
 281         DEBUG("Attempting to extract all images from `%s'", w->filename);
 282
 283         memcpy(buf, w->output_dir, output_path_len);
 284         buf[output_path_len] = '/';
 285         for (image = 1; image <= w->hdr.image_count; image++) {
 286
 287                 image_name = wimlib_get_image_name(w, image);
 288                 if (*image_name) {
 289                         strcpy(buf + output_path_len + 1, image_name);
 290                 } else {
 291                         /* Image name is empty. Use image number instead */
 292                         sprintf(buf + output_path_len + 1, "%d", image);
 293                 }
 294                 ret = set_output_dir(w, buf);
 295                 if (ret != 0)
 296                         goto done;
 297                 ret = extract_single_image(w, image);
 298                 if (ret != 0)
 299                         goto done;
 300         }
 301 done:
 302         /* Restore original output directory */
 303         buf[output_path_len + 1] = '\0';
 304         return 0;
 305 }
 306
 307 /* Extracts a single image or all images from a WIM file. */
 308 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image,
 309                                    const char *output_dir, int flags)
 310 {
 311         int ret;
 312         if (!output_dir)
 313                 return WIMLIB_ERR_INVALID_PARAM;
 314         if ((flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 315                         == (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 316                 return WIMLIB_ERR_INVALID_PARAM;
 317
 318         ret = set_output_dir(w, output_dir);
 319         if (ret != 0)
 320                 return ret;
 321
 322         if ((flags & WIMLIB_EXTRACT_FLAG_NTFS)) {
 323         #ifdef WITH_NTFS_3G
 324                 unsigned long mnt_flags;
 325                 ret = ntfs_check_if_mounted(output_dir, &mnt_flags);
 326                 if (ret != 0) {
 327                         ERROR_WITH_ERRNO("NTFS-3g: Cannot determine if `%s' "
 328                                          "is mounted", output_dir);
 329                         return WIMLIB_ERR_NTFS_3G;
 330                 }
 331                 if (!(mnt_flags & NTFS_MF_MOUNTED)) {
 332                         ERROR("NTFS-3g: Filesystem on `%s' is not mounted ",
 333                               output_dir);
 334                 }
 335                 if (mnt_flags & NTFS_MF_READONLY) {
 336                         ERROR("NTFS-3g: Filesystem on `%s' is mounted "
 337                               "read-only", output_dir);
 338                         return WIMLIB_ERR_NTFS_3G;
 339                 }
 340         #else
 341                 ERROR("wimlib was compiled without support for NTFS-3g, so");
 342                 ERROR("we cannot extract a WIM image while preserving NTFS-");
 343                 ERROR("specific information");
 344                 return WIMLIB_ERR_UNSUPPORTED;
 345         #endif
 346         }
 347         w->extract_flags = flags;
 348         if (image == WIM_ALL_IMAGES) {
 349                 w->is_multi_image_extraction = true;
 350                 ret = extract_all_images(w);
 351         } else {
 352                 w->is_multi_image_extraction = false;
 353                 ret = extract_single_image(w, image);
 354         }
 355         return ret;
 356
 357 }