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   1 /*
   2  * extract.c
   3  *
   4  * Support for extracting WIM files.
   5  *
   6  * This code does NOT contain any filesystem-specific features.  In particular,
   7  * security information (i.e. file permissions) and alternate data streams are
   8  * ignored, except possibly to read an alternate data stream that contains
   9  * symbolic link data.
  10  */
  11
  12 /*
  13  * Copyright (C) 2010 Carl Thijssen
  14  * Copyright (C) 2012 Eric Biggers
  15  *
  16  * This file is part of wimlib, a library for working with WIM files.
  17  *
  18  * wimlib is free software; you can redistribute it and/or modify it under the
  19  * terms of the GNU General Public License as published by the Free
  20  * Software Foundation; either version 3 of the License, or (at your option)
  21  * any later version.
  22  *
  23  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  24  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  25  * A PARTICULAR PURPOSE. See the GNU General Public License for more
  26  * details.
  27  *
  28  * You should have received a copy of the GNU General Public License
  29  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  30  */
  31
  32
  33 #include "config.h"
  34
  35 #include <dirent.h>
  36 #include <errno.h>
  37 #include <fcntl.h>
  38 #include <string.h>
  39 #include <sys/stat.h>
  40 #include <sys/time.h>
  41
  42 #ifdef HAVE_UTIME_H
  43 #include <utime.h>
  44 #endif
  45
  46 #include <unistd.h>
  47
  48 #include "dentry.h"
  49 #include "lookup_table.h"
  50 #include "timestamp.h"
  51 #include "wimlib_internal.h"
  52 #include "xml.h"
  53
  54 /* Internal */
  55 #define WIMLIB_EXTRACT_FLAG_MULTI_IMAGE 0x80000000
  56
  57 static int extract_regular_file_linked(const struct dentry *dentry,
  58                                        const char *output_dir,
  59                                        const char *output_path,
  60                                        int extract_flags,
  61                                        struct lookup_table_entry *lte)
  62 {
  63         /* This mode overrides the normal hard-link extraction and
  64          * instead either symlinks or hardlinks *all* identical files in
  65          * the WIM, even if they are in a different image (in the case
  66          * of a multi-image extraction) */
  67         wimlib_assert(lte->extracted_file);
  68
  69         if (extract_flags & WIMLIB_EXTRACT_FLAG_HARDLINK) {
  70                 if (link(lte->extracted_file, output_path) != 0) {
  71                         ERROR_WITH_ERRNO("Failed to hard link "
  72                                          "`%s' to `%s'",
  73                                          output_path, lte->extracted_file);
  74                         return WIMLIB_ERR_LINK;
  75                 }
  76         } else {
  77                 int num_path_components;
  78                 int num_output_dir_path_components;
  79                 size_t extracted_file_len;
  80                 char *p;
  81                 const char *p2;
  82                 size_t i;
  83
  84                 wimlib_assert(extract_flags & WIMLIB_EXTRACT_FLAG_SYMLINK);
  85
  86                 num_path_components =
  87                         get_num_path_components(dentry->full_path_utf8) - 1;
  88                 num_output_dir_path_components =
  89                         get_num_path_components(output_dir);
  90
  91                 if (extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE) {
  92                         num_path_components++;
  93                         num_output_dir_path_components--;
  94                 }
  95                 extracted_file_len = strlen(lte->extracted_file);
  96
  97                 char buf[extracted_file_len + 3 * num_path_components + 1];
  98                 p = &buf[0];
  99
 100                 for (i = 0; i < num_path_components; i++) {
 101                         *p++ = '.';
 102                         *p++ = '.';
 103                         *p++ = '/';
 104                 }
 105                 p2 = lte->extracted_file;
 106                 while (*p2 == '/')
 107                         p2++;
 108                 while (num_output_dir_path_components--)
 109                         p2 = path_next_part(p2, NULL);
 110                 strcpy(p, p2);
 111                 if (symlink(buf, output_path) != 0) {
 112                         ERROR_WITH_ERRNO("Failed to symlink `%s' to "
 113                                          "`%s'",
 114                                          buf, lte->extracted_file);
 115                         return WIMLIB_ERR_LINK;
 116                 }
 117
 118         }
 119         return 0;
 120 }
 121
 122 static int extract_regular_file_unlinked(WIMStruct *w,
 123                                          struct dentry *dentry,
 124                                          const char *output_path,
 125                                          int extract_flags,
 126                                          struct lookup_table_entry *lte)
 127 {
 128         /* Normal mode of extraction.  Regular files and hard links are
 129          * extracted in the way that they appear in the WIM. */
 130
 131         int out_fd;
 132         int ret;
 133         struct inode *inode = dentry->d_inode;
 134
 135         if (!((extract_flags & WIMLIB_EXTRACT_FLAG_MULTI_IMAGE)
 136                 && (extract_flags & (WIMLIB_EXTRACT_FLAG_SYMLINK |
 137                                      WIMLIB_EXTRACT_FLAG_HARDLINK))))
 138         {
 139                 /* If the dentry is one of a hard link set of at least 2
 140                  * dentries and one of the other dentries has already been
 141                  * extracted, make a hard link to the file corresponding to this
 142                  * already-extracted directory.  Otherwise, extract the file,
 143                  * and set the inode->extracted_file field so that other
 144                  * dentries in the hard link group can link to it. */
 145                 if (inode->link_count > 1) {
 146                         if (inode->extracted_file) {
 147                                 DEBUG("Extracting hard link `%s' => `%s'",
 148                                       output_path, inode->extracted_file);
 149                                 if (link(inode->extracted_file, output_path) != 0) {
 150                                         ERROR_WITH_ERRNO("Failed to hard link "
 151                                                          "`%s' to `%s'",
 152                                                          output_path,
 153                                                          inode->extracted_file);
 154                                         return WIMLIB_ERR_LINK;
 155                                 }
 156                                 return 0;
 157                         }
 158                         FREE(inode->extracted_file);
 159                         inode->extracted_file = STRDUP(output_path);
 160                         if (!inode->extracted_file) {
 161                                 ERROR("Failed to allocate memory for filename");
 162                                 return WIMLIB_ERR_NOMEM;
 163                         }
 164                 }
 165         }
 166
 167         /* Extract the contents of the file to @output_path. */
 168
 169         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 170         if (out_fd == -1) {
 171                 ERROR_WITH_ERRNO("Failed to open the file `%s' for writing",
 172                                  output_path);
 173                 return WIMLIB_ERR_OPEN;
 174         }
 175
 176         if (!lte) {
 177                 /* Empty file with no lookup table entry */
 178                 DEBUG("Empty file `%s'.", output_path);
 179                 ret = 0;
 180                 goto out;
 181         }
 182
 183         ret = extract_full_wim_resource_to_fd(lte, out_fd);
 184         if (ret != 0) {
 185                 ERROR("Failed to extract resource to `%s'", output_path);
 186                 goto out;
 187         }
 188
 189 out:
 190         if (close(out_fd) != 0) {
 191                 ERROR_WITH_ERRNO("Failed to close file `%s'", output_path);
 192                 ret = WIMLIB_ERR_WRITE;
 193         }
 194         return ret;
 195 }
 196
 197 /*
 198  * Extracts a regular file from the WIM archive.
 199  */
 200 static int extract_regular_file(WIMStruct *w,
 201                                 struct dentry *dentry,
 202                                 const char *output_dir,
 203                                 const char *output_path,
 204                                 int extract_flags)
 205 {
 206         struct lookup_table_entry *lte;
 207         const struct inode *inode = dentry->d_inode;
 208
 209         lte = inode_unnamed_lte(inode, w->lookup_table);
 210
 211         if ((extract_flags & (WIMLIB_EXTRACT_FLAG_SYMLINK |
 212                               WIMLIB_EXTRACT_FLAG_HARDLINK)) && lte) {
 213                 if (lte->extracted_file) {
 214                         return extract_regular_file_linked(dentry, output_dir,
 215                                                            output_path,
 216                                                            extract_flags, lte);
 217                 } else {
 218                         lte->extracted_file = STRDUP(output_path);
 219                         if (!lte->extracted_file)
 220                                 return WIMLIB_ERR_NOMEM;
 221                 }
 222         }
 223
 224         return extract_regular_file_unlinked(w, dentry, output_path,
 225                                              extract_flags, lte);
 226
 227 }
 228
 229 static int extract_symlink(const struct dentry *dentry, const char *output_path,
 230                            const WIMStruct *w)
 231 {
 232         char target[4096];
 233         ssize_t ret = inode_readlink(dentry->d_inode, target,
 234                                      sizeof(target), w, 0);
 235         if (ret <= 0) {
 236                 ERROR("Could not read the symbolic link from dentry `%s'",
 237                       dentry->full_path_utf8);
 238                 return WIMLIB_ERR_INVALID_DENTRY;
 239         }
 240         ret = symlink(target, output_path);
 241         if (ret != 0) {
 242                 ERROR_WITH_ERRNO("Failed to symlink `%s' to `%s'",
 243                                  output_path, target);
 244                 return WIMLIB_ERR_LINK;
 245         }
 246         return 0;
 247 }
 248
 249 /*
 250  * Extracts a directory from the WIM archive.
 251  *
 252  * @dentry:             The directory entry for the directory.
 253  * @output_path:        The path to which the directory is to be extracted to.
 254  * @return:             True on success, false on failure.
 255  */
 256 static int extract_directory(const char *output_path, bool is_root)
 257 {
 258         int ret;
 259         struct stat stbuf;
 260         ret = stat(output_path, &stbuf);
 261         if (ret == 0) {
 262                 if (S_ISDIR(stbuf.st_mode)) {
 263                         if (!is_root)
 264                                 WARNING("`%s' already exists", output_path);
 265                         return 0;
 266                 } else {
 267                         ERROR("`%s' is not a directory", output_path);
 268                         return WIMLIB_ERR_MKDIR;
 269                 }
 270         } else {
 271                 if (errno != ENOENT) {
 272                         ERROR_WITH_ERRNO("Failed to stat `%s'", output_path);
 273                         return WIMLIB_ERR_STAT;
 274                 }
 275         }
 276         /* Compute the output path directory to the directory. */
 277         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP |
 278                                S_IROTH | S_IXOTH) != 0) {
 279                 ERROR_WITH_ERRNO("Cannot create directory `%s'",
 280                                  output_path);
 281                 return WIMLIB_ERR_MKDIR;
 282         }
 283         return 0;
 284 }
 285
 286 struct extract_args {
 287         WIMStruct *w;
 288         int extract_flags;
 289         const char *output_dir;
 290         unsigned num_lutimes_warnings;
 291 };
 292
 293 /*
 294  * Extracts a file, directory, or symbolic link from the WIM archive.  For use
 295  * in for_dentry_in_tree().
 296  */
 297 static int extract_dentry(struct dentry *dentry, void *arg)
 298 {
 299         struct extract_args *args = arg;
 300         WIMStruct *w = args->w;
 301         int extract_flags = args->extract_flags;
 302         size_t len = strlen(args->output_dir);
 303         char output_path[len + dentry->full_path_utf8_len + 1];
 304
 305         if (extract_flags & WIMLIB_EXTRACT_FLAG_VERBOSE) {
 306                 wimlib_assert(dentry->full_path_utf8);
 307                 puts(dentry->full_path_utf8);
 308         }
 309
 310         memcpy(output_path, args->output_dir, len);
 311         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 312         output_path[len + dentry->full_path_utf8_len] = '\0';
 313
 314         if (dentry_is_symlink(dentry))
 315                 return extract_symlink(dentry, output_path, w);
 316         else if (dentry_is_directory(dentry))
 317                 return extract_directory(output_path, dentry_is_root(dentry));
 318         else
 319                 return extract_regular_file(w, dentry, args->output_dir,
 320                                             output_path, extract_flags);
 321 }
 322
 323 /* Apply timestamp to extracted file */
 324 static int apply_dentry_timestamps(struct dentry *dentry, void *arg)
 325 {
 326         struct extract_args *args = arg;
 327         size_t len = strlen(args->output_dir);
 328         char output_path[len + dentry->full_path_utf8_len + 1];
 329         const struct inode *inode = dentry->d_inode;
 330         int ret;
 331
 332         memcpy(output_path, args->output_dir, len);
 333         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 334         output_path[len + dentry->full_path_utf8_len] = '\0';
 335
 336         struct timeval tv[2];
 337         wim_timestamp_to_timeval(inode->last_access_time, &tv[0]);
 338         wim_timestamp_to_timeval(inode->last_write_time, &tv[1]);
 339         #ifdef HAVE_LUTIMES
 340         ret = lutimes(output_path, tv);
 341         #else
 342         ret = -1;
 343         errno = ENOSYS;
 344         #endif
 345         if (ret != 0) {
 346                 #ifdef HAVE_UTIME
 347                 if (errno == ENOSYS) {
 348                         struct utimbuf buf;
 349                         buf.actime = wim_timestamp_to_unix(inode->last_access_time);
 350                         buf.modtime = wim_timestamp_to_unix(inode->last_write_time);
 351                         if (utime(output_path, &buf) == 0)
 352                                 return 0;
 353                 }
 354                 #endif
 355                 if (errno != ENOSYS || args->num_lutimes_warnings < 10) {
 356                         WARNING("Failed to set timestamp on file `%s': %s",
 357                                 output_path, strerror(errno));
 358                         args->num_lutimes_warnings++;
 359                 }
 360         }
 361         return 0;
 362 }
 363
 364
 365 static int extract_single_image(WIMStruct *w, int image,
 366                                 const char *output_dir, int extract_flags)
 367 {
 368         DEBUG("Extracting image %d", image);
 369
 370         int ret;
 371         ret = select_wim_image(w, image);
 372         if (ret != 0)
 373                 return ret;
 374
 375         struct extract_args args = {
 376                 .w                    = w,
 377                 .extract_flags        = extract_flags,
 378                 .output_dir           = output_dir,
 379                 .num_lutimes_warnings = 0,
 380         };
 381
 382         ret = for_dentry_in_tree(wim_root_dentry(w), extract_dentry, &args);
 383         if (ret != 0)
 384                 return ret;
 385         return for_dentry_in_tree_depth(wim_root_dentry(w),
 386                                         apply_dentry_timestamps, &args);
 387
 388 }
 389
 390
 391 /* Extracts all images from the WIM to @output_dir, with the images placed in
 392  * subdirectories named by their image names. */
 393 static int extract_all_images(WIMStruct *w, const char *output_dir,
 394                               int extract_flags)
 395 {
 396         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 397         size_t output_path_len = strlen(output_dir);
 398         char buf[output_path_len + 1 + image_name_max_len + 1];
 399         int ret;
 400         int image;
 401         const char *image_name;
 402
 403         DEBUG("Attempting to extract all images from `%s' to `%s'",
 404               w->filename, output_dir);
 405
 406         ret = extract_directory(output_dir, true);
 407         if (ret != 0)
 408                 return ret;
 409
 410         memcpy(buf, output_dir, output_path_len);
 411         buf[output_path_len] = '/';
 412         for (image = 1; image <= w->hdr.image_count; image++) {
 413
 414                 image_name = wimlib_get_image_name(w, image);
 415                 if (*image_name) {
 416                         strcpy(buf + output_path_len + 1, image_name);
 417                 } else {
 418                         /* Image name is empty. Use image number instead */
 419                         sprintf(buf + output_path_len + 1, "%d", image);
 420                 }
 421                 ret = extract_single_image(w, image, buf, extract_flags);
 422                 if (ret != 0)
 423                         return ret;
 424         }
 425         return 0;
 426 }
 427
 428
 429 /* Extracts a single image or all images from a WIM file. */
 430 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image,
 431                                    const char *output_dir, int flags,
 432                                    WIMStruct **additional_swms,
 433                                    unsigned num_additional_swms)
 434 {
 435         struct lookup_table *joined_tab, *w_tab_save;
 436         int ret;
 437
 438         DEBUG("w->filename = %s, image = %d, output_dir = %s, flags = 0x%x, "
 439               "num_additional_swms = %u",
 440               w->filename, image, output_dir, flags, num_additional_swms);
 441
 442         if (!w || !output_dir)
 443                 return WIMLIB_ERR_INVALID_PARAM;
 444
 445         if ((flags & (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 446                         == (WIMLIB_EXTRACT_FLAG_SYMLINK | WIMLIB_EXTRACT_FLAG_HARDLINK))
 447                 return WIMLIB_ERR_INVALID_PARAM;
 448
 449         ret = verify_swm_set(w, additional_swms, num_additional_swms);
 450         if (ret != 0)
 451                 return ret;
 452
 453         if (num_additional_swms) {
 454                 ret = new_joined_lookup_table(w, additional_swms,
 455                                               num_additional_swms, &joined_tab);
 456                 if (ret != 0)
 457                         return ret;
 458                 w_tab_save = w->lookup_table;
 459                 w->lookup_table = joined_tab;
 460         }
 461
 462         for_lookup_table_entry(w->lookup_table, lte_zero_extracted_file, NULL);
 463
 464         if (image == WIM_ALL_IMAGES) {
 465                 flags |= WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 466                 ret = extract_all_images(w, output_dir, flags);
 467         } else {
 468                 flags &= ~WIMLIB_EXTRACT_FLAG_MULTI_IMAGE;
 469                 ret = extract_single_image(w, image, output_dir, flags);
 470         }
 471         if (num_additional_swms) {
 472                 free_lookup_table(w->lookup_table);
 473                 w->lookup_table = w_tab_save;
 474         }
 475         for_lookup_table_entry(w->lookup_table, lte_free_extracted_file, NULL);
 476         return ret;
 477
 478 }