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