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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 #include <ntfs-3g/security.h>
  41 #endif
  42
  43 /* Internal */
  44 #define WIMLIB_EXTRACT_FLAG_MULTI_IMAGE 0x80000000
  45
  46 /* Sets and creates the directory to which files are to be extracted when
  47  * extracting files from the WIM. */
  48 static int make_output_dir(const char *dir)
  49 {
  50         char *p;
  51         DEBUG("Setting output directory to `%s'", dir);
  52
  53         if (mkdir(dir, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0) {
  54                 if (errno == EEXIST) {
  55                         DEBUG("`%s' already exists", dir);
  56                         return 0;
  57                 }
  58                 ERROR_WITH_ERRNO("Cannot create directory `%s'", dir);
  59                 return WIMLIB_ERR_MKDIR;
  60         } else {
  61                 DEBUG("Created directory `%s'", dir);
  62         }
  63         return 0;
  64 }
  65
  66 static int extract_regular_file_linked(const struct dentry *dentry,
  67                                        const char *output_dir,
  68                                        const char *output_path,
  69                                        int extract_flags,
  70                                        const struct lookup_table_entry *lte)
  71 {
  72         /* This mode overrides the normal hard-link extraction and
  73          * instead either symlinks or hardlinks *all* identical files in
  74          * the WIM, even if they are in a different image (in the case
  75          * of a multi-image extraction) */
  76         wimlib_assert(lte->file_on_disk);
  77
  78         if (extract_flags & WIMLIB_EXTRACT_FLAG_HARDLINK) {
  79                 if (link(lte->file_on_disk, output_path) != 0) {
  80                         ERROR_WITH_ERRNO("Failed to hard link "
  81                                          "`%s' to `%s'",
  82                                          output_path, lte->file_on_disk);
  83                         return WIMLIB_ERR_LINK;
  84                 }
  85         } else {
  86                 int num_path_components;
  87                 int num_output_dir_path_components;
  88                 size_t file_on_disk_len;
  89                 char *p;
  90                 const char *p2;
  91                 size_t i;
  92
  93                 num_path_components =
  94                         get_num_path_components(dentry->full_path_utf8) - 1;
  95                 num_output_dir_path_components =
  96                         get_num_path_components(output_dir);
  97
  98                 if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
  99                         num_path_components++;
 100                         num_output_dir_path_components--;
 101                 }
 102                 file_on_disk_len = strlen(lte->file_on_disk);
 103
 104                 char buf[file_on_disk_len + 3 * num_path_components + 1];
 105                 p = &buf[0];
 106
 107                 for (i = 0; i < num_path_components; i++) {
 108                         *p++ = '.';
 109                         *p++ = '.';
 110                         *p++ = '/';
 111                 }
 112                 p2 = lte->file_on_disk;
 113                 while (*p2 == '/')
 114                         p2++;
 115                 while (num_output_dir_path_components--)
 116                         p2 = path_next_part(p2, NULL);
 117                 strcpy(p, p2);
 118                 if (symlink(buf, output_path) != 0) {
 119                         ERROR_WITH_ERRNO("Failed to symlink `%s' to "
 120                                          "`%s'",
 121                                          buf, lte->file_on_disk);
 122                         return WIMLIB_ERR_LINK;
 123                 }
 124
 125         }
 126         return 0;
 127 }
 128
 129 static int extract_regular_file_unlinked(WIMStruct *w,
 130                                          const struct dentry *dentry,
 131                                          const char *output_path,
 132                                          int extract_flags,
 133                                          struct lookup_table_entry *lte)
 134 {
 135         int out_fd;
 136         const struct resource_entry *res_entry;
 137         int ret;
 138         /* Otherwise, we must actually extract the file contents. */
 139
 140         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 141         if (out_fd == -1) {
 142                 ERROR_WITH_ERRNO("Failed to open the file `%s' for writing",
 143                                  output_path);
 144                 return WIMLIB_ERR_OPEN;
 145         }
 146
 147         /* Extract empty file, with no lookup table entry... */
 148         if (!lte) {
 149                 DEBUG("Empty file `%s'.", output_path);
 150                 ret = 0;
 151                 goto done;
 152         }
 153
 154         res_entry = &lte->resource_entry;
 155
 156         ret = extract_resource_to_fd(w, res_entry, out_fd,
 157                                      res_entry->original_size);
 158
 159         if (ret != 0) {
 160                 ERROR("Failed to extract resource to `%s'", output_path);
 161                 goto done;
 162         }
 163
 164         /* Mark the lookup table entry to indicate this file has been extracted. */
 165         lte->out_refcnt++;
 166         FREE(lte->file_on_disk);
 167         lte->file_on_disk = STRDUP(output_path);
 168         if (!lte->file_on_disk)
 169                 ret = WIMLIB_ERR_NOMEM;
 170 done:
 171         close(out_fd);
 172         return ret;
 173 }
 174
 175 /*
 176  * Extracts a regular file from the WIM archive.
 177  */
 178 static int extract_regular_file(WIMStruct *w,
 179                                 const struct dentry *dentry,
 180                                 const char *output_dir,
 181                                 const char *output_path,
 182                                 int extract_flags)
 183 {
 184         struct lookup_table_entry *lte;
 185
 186         lte = __lookup_resource(w->lookup_table, dentry_hash(dentry));
 187
 188         /* If we already extracted the same file or a hard link copy of it, we
 189          * may be able to simply create a link.  The exact action is specified
 190          * by the current @link_type. */
 191         if ((extract_flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK)) &&
 192               lte && lte->out_refcnt != 0)
 193                 return extract_regular_file_linked(dentry, output_dir,
 194                                                    output_path, extract_flags,
 195                                                    lte);
 196         else
 197                 return extract_regular_file_unlinked(w, dentry, output_path,
 198                                                      extract_flags, lte);
 199
 200 }
 201
 202 static int extract_symlink(const struct dentry *dentry, const char *output_path,
 203                            const WIMStruct *w)
 204 {
 205         char target[4096];
 206         ssize_t ret = dentry_readlink(dentry, target, sizeof(target), w);
 207         if (ret <= 0) {
 208                 ERROR("Could not read the symbolic link from dentry `%s'",
 209                       dentry->full_path_utf8);
 210                 return WIMLIB_ERR_INVALID_DENTRY;
 211         }
 212         ret = symlink(target, output_path);
 213         if (ret != 0) {
 214                 ERROR_WITH_ERRNO("Failed to symlink `%s' to `%s'",
 215                                  output_path, target);
 216                 return WIMLIB_ERR_LINK;
 217         }
 218         return 0;
 219 }
 220
 221 /*
 222  * Extracts a directory from the WIM archive.
 223  *
 224  * @dentry:             The directory entry for the directory.
 225  * @output_path:        The path to which the directory is to be extracted to.
 226  * @return:             True on success, false on failure.
 227  */
 228 static int extract_directory(struct dentry *dentry, const char *output_path)
 229 {
 230         /* Compute the output path directory to the directory. */
 231         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0)
 232         {
 233                 switch (errno) {
 234                 case EEXIST: /* Already existing directory is OK */
 235                 case EACCES: /* We may have permissions to extract files inside
 236                                  the directory, but not for the directory
 237                                  itself. */
 238                         return 0;
 239                 default:
 240                         ERROR_WITH_ERRNO("Cannot create directory `%s'",
 241                                          output_path);
 242                         return WIMLIB_ERR_MKDIR;
 243                 }
 244         }
 245         return 0;
 246 }
 247
 248 struct extract_args {
 249         WIMStruct *w;
 250         int extract_flags;
 251         const char *output_dir;
 252 #ifdef WITH_NTFS_3G
 253         struct SECURITY_API *scapi;
 254 #endif
 255 };
 256
 257 /*
 258  * Extracts a file or directory from the WIM archive.  For use in
 259  * for_dentry_in_tree().
 260  *
 261  * @dentry:     The dentry to extract.
 262  * @arg:        A pointer to the WIMStruct for the WIM file.
 263  */
 264 static int extract_dentry(struct dentry *dentry, void *arg)
 265 {
 266         struct extract_args *args = arg;
 267         WIMStruct *w = args->w;
 268         int extract_flags = args->extract_flags;
 269         size_t len = strlen(args->output_dir);
 270         char output_path[len + dentry->full_path_utf8_len + 1];
 271         int ret = 0;
 272
 273         if (extract_flags & WIMLIB_EXTRACT_FLAG_VERBOSE)
 274                 puts(dentry->full_path_utf8);
 275
 276         memcpy(output_path, args->output_dir, len);
 277         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 278         output_path[len + dentry->full_path_utf8_len] = '\0';
 279
 280         if (dentry_is_symlink(dentry)) {
 281                 ret = extract_symlink(dentry, output_path, w);
 282         } else if (dentry_is_directory(dentry)) {
 283                 if (!dentry_is_root(dentry)) /* Root doesn't need to be extracted. */
 284                         ret = extract_directory(dentry, output_path);
 285         } else {
 286                 ret = extract_regular_file(w, dentry, args->output_dir,
 287                                            output_path, extract_flags);
 288         }
 289         return ret;
 290 }
 291
 292
 293 static int extract_single_image(WIMStruct *w, int image,
 294                                 const char *output_dir, int extract_flags)
 295 {
 296         DEBUG("Extracting image %d", image);
 297
 298         int ret;
 299         ret = wimlib_select_image(w, image);
 300         if (ret != 0)
 301                 return ret;
 302
 303         struct extract_args args = {
 304                 .w = w,
 305                 .extract_flags = extract_flags,
 306                 .output_dir = output_dir,
 307         #ifdef WITH_NTFS_3G
 308                 .scapi = NULL
 309         #endif
 310         };
 311
 312         return for_dentry_in_tree(wim_root_dentry(w), extract_dentry, &args);
 313 }
 314
 315
 316 /* Extracts all images from the WIM to @output_dir, with the images placed in
 317  * subdirectories named by their image names. */
 318 static int extract_all_images(WIMStruct *w, const char *output_dir,
 319                               int extract_flags)
 320 {
 321         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 322         size_t output_path_len = strlen(output_dir);
 323         char buf[output_path_len + 1 + image_name_max_len + 1];
 324         int ret;
 325         int image;
 326         const char *image_name;
 327
 328         DEBUG("Attempting to extract all images from `%s'", w->filename);
 329
 330         memcpy(buf, output_dir, output_path_len);
 331         buf[output_path_len] = '/';
 332         for (image = 1; image <= w->hdr.image_count; image++) {
 333
 334                 image_name = wimlib_get_image_name(w, image);
 335                 if (*image_name) {
 336                         strcpy(buf + output_path_len + 1, image_name);
 337                 } else {
 338                         /* Image name is empty. Use image number instead */
 339                         sprintf(buf + output_path_len + 1, "%d", image);
 340                 }
 341                 ret = make_output_dir(buf);
 342                 if (ret != 0)
 343                         goto done;
 344                 ret = extract_single_image(w, image, buf, extract_flags);
 345                 if (ret != 0)
 346                         goto done;
 347         }
 348 done:
 349         /* Restore original output directory */
 350         buf[output_path_len + 1] = '\0';
 351         return 0;
 352 }
 353
 354 /* Extracts a single image or all images from a WIM file. */
 355 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image,
 356                                    const char *output_dir, int flags)
 357 {
 358         int ret;
 359         if (!output_dir)
 360                 return WIMLIB_ERR_INVALID_PARAM;
 361         if ((flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 362                         == (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 363                 return WIMLIB_ERR_INVALID_PARAM;
 364
 365         if (image == WIM_ALL_IMAGES)
 366                 flags |= WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 367         else
 368                 flags &= ~WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 369
 370         ret = make_output_dir(output_dir);
 371         if (ret != 0)
 372                 return ret;
 373
 374         if ((flags & WIMLIB_EXTRACT_FLAG_NTFS)) {
 375         #ifdef WITH_NTFS_3G
 376                 unsigned long mnt_flags;
 377                 ret = ntfs_check_if_mounted(output_dir, &mnt_flags);
 378                 if (ret != 0) {
 379                         ERROR_WITH_ERRNO("NTFS-3g: Cannot determine if `%s' "
 380                                          "is mounted", output_dir);
 381                         return WIMLIB_ERR_NTFS_3G;
 382                 }
 383                 if (!(mnt_flags & NTFS_MF_MOUNTED)) {
 384                         ERROR("NTFS-3g: Filesystem on `%s' is not mounted ",
 385                               output_dir);
 386                 }
 387                 if (mnt_flags & NTFS_MF_READONLY) {
 388                         ERROR("NTFS-3g: Filesystem on `%s' is mounted "
 389                               "read-only", output_dir);
 390                         return WIMLIB_ERR_NTFS_3G;
 391                 }
 392         #else
 393                 ERROR("wimlib was compiled without support for NTFS-3g, so");
 394                 ERROR("we cannot extract a WIM image while preserving NTFS-");
 395                 ERROR("specific information");
 396                 return WIMLIB_ERR_UNSUPPORTED;
 397         #endif
 398         }
 399         if (image == WIM_ALL_IMAGES)
 400                 ret = extract_all_images(w, output_dir, flags);
 401         else
 402                 ret = extract_single_image(w, image, output_dir, flags);
 403         return ret;
 404
 405 }