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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
  39 /*
  40  * Extracts a regular file from the WIM archive.
  41  *
  42  * @dentry:             The directory entry for the file, which must be a
  43  *                              regular file.
  44  * @output_path:        The path to which the file is to be extracted.
  45  * @lookup_table:       The lookup table for the WIM file.
  46  * @wim_fp:             The FILE* for the WIM, opened for reading.
  47  * @wim_ctype:          The type of compression used in the WIM.
  48  * @link_type:          One of WIM_LINK_TYPE_*; specifies what to do with
  49  *                      files that are hard-linked inside the WIM.
  50  * @is_multi_image_extraction:
  51  *                      True if the image currently being extracted is just one
  52  *                      image of a multi-image extraction.  This is needed so
  53  *                      that cross-image symbolic links can be created
  54  *                      correctly.
  55  */
  56 static int extract_regular_file(WIMStruct *w,
  57                                 const struct dentry *dentry,
  58                                 const char *output_path)
  59 {
  60         struct lookup_table *lookup_table;
  61         int link_type;
  62         bool is_multi_image_extraction;
  63         struct lookup_table_entry *lte;
  64         int ret;
  65         int out_fd;
  66         const struct resource_entry *res_entry;
  67
  68         lookup_table = w->lookup_table;
  69         link_type = w->link_type;
  70         is_multi_image_extraction = w->is_multi_image_extraction;
  71         lte = lookup_resource(lookup_table, dentry->hash);
  72
  73         /* If we already extracted the same file or a hard link copy of it, we
  74          * may be able to simply create a link.  The exact action is specified
  75          * by the current @link_type. */
  76         if (link_type != WIM_LINK_TYPE_NONE && lte && lte->out_refcnt != 0) {
  77                 wimlib_assert(lte->file_on_disk);
  78
  79                 if (link_type == WIM_LINK_TYPE_HARD) {
  80                         if (link(lte->file_on_disk, output_path) != 0) {
  81                                 ERROR_WITH_ERRNO("Failed to hard link "
  82                                                  "`%s' to `%s'",
  83                                                  output_path, lte->file_on_disk);
  84                                 return WIMLIB_ERR_LINK;
  85                         }
  86                 } else {
  87                         int num_path_components;
  88                         int num_output_dir_path_components;
  89                         size_t file_on_disk_len;
  90                         char *p;
  91                         const char *p2;
  92                         size_t i;
  93
  94                         num_path_components =
  95                                 get_num_path_components(dentry->full_path_utf8) - 1;
  96                         num_output_dir_path_components =
  97                                 get_num_path_components(w->output_dir);
  98
  99                         if (is_multi_image_extraction) {
 100                                 num_path_components++;
 101                                 num_output_dir_path_components--;
 102                         }
 103                         file_on_disk_len = strlen(lte->file_on_disk);
 104
 105                         char buf[file_on_disk_len + 3 * num_path_components + 1];
 106                         p = &buf[0];
 107
 108                         for (i = 0; i < num_path_components; i++) {
 109                                 *p++ = '.';
 110                                 *p++ = '.';
 111                                 *p++ = '/';
 112                         }
 113                         p2 = lte->file_on_disk;
 114                         while (*p2 == '/')
 115                                 p2++;
 116                         while (num_output_dir_path_components--)
 117                                 p2 = path_next_part(p2, NULL);
 118                         strcpy(p, p2);
 119                         if (symlink(buf, output_path) != 0) {
 120                                 ERROR_WITH_ERRNO("Failed to symlink `%s' to "
 121                                                  "`%s'",
 122                                                  buf, lte->file_on_disk);
 123                                 return WIMLIB_ERR_LINK;
 124                         }
 125
 126                 }
 127                 return 0;
 128         }
 129
 130         /* Otherwise, we must actually extract the file contents. */
 131
 132         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 133         if (out_fd == -1) {
 134                 ERROR_WITH_ERRNO("Failed to open the file `%s' for writing",
 135                                  output_path);
 136                 return WIMLIB_ERR_OPEN;
 137         }
 138
 139         /* Extract empty file, with no lookup table entry... */
 140         if (!lte) {
 141                 DEBUG("Empty file `%s'.", output_path);
 142                 ret = 0;
 143                 goto done;
 144         }
 145
 146         res_entry = &lte->resource_entry;
 147
 148         ret = extract_resource_to_fd(w, res_entry, out_fd,
 149                                      res_entry->original_size);
 150
 151         if (ret != 0) {
 152                 ERROR("Failed to extract resource to `%s'", output_path);
 153                 goto done;
 154         }
 155
 156         /* Mark the lookup table entry to indicate this file has been extracted. */
 157         lte->out_refcnt++;
 158         FREE(lte->file_on_disk);
 159         lte->file_on_disk = STRDUP(output_path);
 160         if (lte->file_on_disk)
 161                 ret = 0;
 162         else
 163                 ret = WIMLIB_ERR_NOMEM;
 164 done:
 165         close(out_fd);
 166         return ret;
 167 }
 168
 169 /*
 170  * Extracts a directory from the WIM archive.
 171  *
 172  * @dentry:             The directory entry for the directory.
 173  * @output_path:        The path to which the directory is to be extracted to.
 174  * @return:             True on success, false on failure.
 175  */
 176 static int extract_directory(struct dentry *dentry, const char *output_path)
 177 {
 178         /* Compute the output path directory to the directory. */
 179         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0)
 180         {
 181                 switch (errno) {
 182                 case EEXIST: /* Already existing directory is OK */
 183                 case EACCES: /* We may have permissions to extract files inside
 184                                  the directory, but not for the directory
 185                                  itself. */
 186                         return 0;
 187                 default:
 188                         ERROR_WITH_ERRNO("Cannot create directory `%s'",
 189                                          output_path);
 190                         return WIMLIB_ERR_MKDIR;
 191                 }
 192         }
 193         return 0;
 194 }
 195
 196
 197 /*
 198  * Extracts a file or directory from the WIM archive.  For use in
 199  * for_dentry_in_tree().
 200  *
 201  * @dentry:     The dentry to extract.
 202  * @arg:        A pointer to the WIMStruct for the WIM file.
 203  */
 204 static int extract_regular_file_or_directory(struct dentry *dentry, void *arg)
 205 {
 206         WIMStruct *w = (WIMStruct*)arg;
 207         size_t len = strlen(w->output_dir);
 208         char output_path[len + dentry->full_path_utf8_len + 1];
 209
 210         if (w->verbose)
 211                 puts(dentry->full_path_utf8);
 212
 213         memcpy(output_path, w->output_dir, len);
 214         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 215         output_path[len + dentry->full_path_utf8_len] = '\0';
 216
 217
 218         if (dentry_is_regular_file(dentry)) {
 219                 return extract_regular_file(w, dentry, output_path);
 220         } else {
 221                 if (dentry_is_root(dentry)) /* Root doesn't need to be extracted. */
 222                         return 0;
 223                 else
 224                         return extract_directory(dentry, output_path);
 225         }
 226 }
 227
 228 static int extract_single_image(WIMStruct *w, int image)
 229 {
 230         DEBUG("Extracting image %d", image);
 231
 232         int ret;
 233         ret = wimlib_select_image(w, image);
 234         if (ret != 0)
 235                 return ret;
 236
 237         return for_dentry_in_tree(wim_root_dentry(w),
 238                                   extract_regular_file_or_directory, w);
 239 }
 240
 241
 242 /* Extracts all images from the WIM to w->output_dir, with the images placed in
 243  * subdirectories named by their image names. */
 244 static int extract_all_images(WIMStruct *w)
 245 {
 246         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 247         size_t output_path_len = strlen(w->output_dir);
 248         char buf[output_path_len + 1 + image_name_max_len + 1];
 249         int ret;
 250         int image;
 251         const char *image_name;
 252
 253         DEBUG("Attempting to extract all images from `%s'", w->filename);
 254
 255         memcpy(buf, w->output_dir, output_path_len);
 256         buf[output_path_len] = '/';
 257         for (image = 1; image <= w->hdr.image_count; image++) {
 258
 259                 image_name = wimlib_get_image_name(w, image);
 260                 if (*image_name) {
 261                         strcpy(buf + output_path_len + 1, image_name);
 262                 } else {
 263                         /* Image name is empty. Use image number instead */
 264                         sprintf(buf + output_path_len + 1, "%d", image);
 265                 }
 266                 ret = wimlib_set_output_dir(w, buf);
 267                 if (ret != 0)
 268                         goto done;
 269                 ret = extract_single_image(w, image);
 270                 if (ret != 0)
 271                         goto done;
 272         }
 273 done:
 274         /* Restore original output directory */
 275         buf[output_path_len + 1] = '\0';
 276         return wimlib_set_output_dir(w, buf);
 277 }
 278
 279 /* Extracts a single image or all images from a WIM file. */
 280 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image)
 281 {
 282         if (!w->output_dir) {
 283                 ERROR("No output directory selected.");
 284                 return WIMLIB_ERR_NOTDIR;
 285         }
 286         if (image == WIM_ALL_IMAGES) {
 287                 w->is_multi_image_extraction = true;
 288                 return extract_all_images(w);
 289         } else {
 290                 w->is_multi_image_extraction = false;
 291                 return extract_single_image(w, image);
 292         }
 293
 294 }
 295
 296 /* Sets and creates the directory to which files are to be extracted when
 297  * extracting files from the WIM. */
 298 WIMLIBAPI int wimlib_set_output_dir(WIMStruct *w, const char *dir)
 299 {
 300         char *p;
 301         DEBUG("Setting output directory to `%s'", dir);
 302
 303         if (!dir) {
 304                 ERROR("Must specify a directory!");
 305                 return WIMLIB_ERR_INVALID_PARAM;
 306         }
 307         p = STRDUP(dir);
 308         if (!p) {
 309                 ERROR("Out of memory");
 310                 return WIMLIB_ERR_NOMEM;
 311         }
 312
 313         if (mkdir(dir, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0) {
 314                 if (errno == EEXIST) {
 315                         DEBUG("`%s' already exists", dir);
 316                         goto done;
 317                 }
 318                 ERROR_WITH_ERRNO("Cannot create directory `%s'", dir);
 319                 FREE(p);
 320                 return WIMLIB_ERR_MKDIR;
 321         } else {
 322                 DEBUG("Created directory `%s'", dir);
 323         }
 324 done:
 325         FREE(w->output_dir);
 326         w->output_dir = p;
 327         return 0;
 328 }
 329
 330 WIMLIBAPI int wimlib_set_link_type(WIMStruct *w, int link_type)
 331 {
 332         switch (link_type) {
 333                 case WIM_LINK_TYPE_NONE:
 334                 case WIM_LINK_TYPE_HARD:
 335                 case WIM_LINK_TYPE_SYMBOLIC:
 336                         w->link_type = link_type;
 337                         return 0;
 338                 default:
 339                         return WIMLIB_ERR_INVALID_PARAM;
 340         }
 341 }
 342