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   1 /*
   2  * extract.c
   3  *
   4  * Support for extracting WIM files.
   5  *
   6  * Copyright (C) 2010 Carl Thijssen
   7  * Copyright (C) 2012 Eric Biggers
   8  *
   9  * wimlib - Library for working with WIM files
  10  *
  11  * This library is free software; you can redistribute it and/or modify it under
  12  * the terms of the GNU Lesser General Public License as published by the Free
  13  * Software Foundation; either version 2.1 of the License, or (at your option) any
  14  * later version.
  15  *
  16  * This library is distributed in the hope that it will be useful, but WITHOUT ANY
  17  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
  18  * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License along
  21  * with this library; if not, write to the Free Software Foundation, Inc., 59
  22  * Temple Place, Suite 330, Boston, MA 02111-1307 USA
  23  */
  24
  25 #include "wimlib_internal.h"
  26 #include "dentry.h"
  27 #include "lookup_table.h"
  28 #include "xml.h"
  29 #include <sys/stat.h>
  30 #include <fcntl.h>
  31 #include <unistd.h>
  32 #include <dirent.h>
  33 #include <string.h>
  34 #include <errno.h>
  35
  36
  37 /*
  38  * Extracts a regular file from the WIM archive.
  39  *
  40  * @dentry:             The directory entry for the file, which must be a
  41  *                              regular file.
  42  * @output_path:        The path to which the file is to be extracted.
  43  * @lookup_table:       The lookup table for the WIM file.
  44  * @wim_fp:             The FILE* for the WIM, opened for reading.
  45  * @wim_ctype:          The type of compression used in the WIM.
  46  * @link_type:          One of WIM_LINK_TYPE_*; specifies what to do with
  47  *                      files that are hard-linked inside the WIM.
  48  * @is_multi_image_extraction:
  49  *                      True if the image currently being extracted is just one
  50  *                      image of a multi-image extraction.  This is needed so
  51  *                      that cross-image symbolic links can be created
  52  *                      correctly.
  53  */
  54 static int extract_regular_file(WIMStruct *w,
  55                                 const struct dentry *dentry,
  56                                 const char *output_path)
  57 {
  58         struct lookup_table *lookup_table;
  59         int link_type;
  60         bool is_multi_image_extraction;
  61         struct lookup_table_entry *lte;
  62         int ret;
  63         int out_fd;
  64         const struct resource_entry *res_entry;
  65
  66         lookup_table = w->lookup_table;
  67         link_type = w->link_type;
  68         is_multi_image_extraction = w->is_multi_image_extraction;
  69         lte = lookup_resource(lookup_table, dentry->hash);
  70
  71         /* If we already extracted the same file or a hard link copy of it, we
  72          * may be able to simply create a link.  The exact action is specified
  73          * by the current @link_type. */
  74         if (link_type != WIM_LINK_TYPE_NONE && lte && lte->out_refcnt != 0) {
  75                 wimlib_assert(lte->file_on_disk);
  76
  77                 if (link_type == WIM_LINK_TYPE_HARD) {
  78                         if (link(lte->file_on_disk, output_path) != 0) {
  79                                 ERROR("Failed to hard link `%s' to `%s': %m\n",
  80                                                 output_path, lte->file_on_disk);
  81                                 return WIMLIB_ERR_LINK;
  82                         }
  83                 } else {
  84                         int num_path_components;
  85                         int num_output_dir_path_components;
  86                         size_t file_on_disk_len;
  87                         char *p;
  88                         const char *p2;
  89                         size_t i;
  90
  91                         num_path_components =
  92                                 get_num_path_components(dentry->full_path_utf8) - 1;
  93                         num_output_dir_path_components =
  94                                 get_num_path_components(w->output_dir);
  95
  96                         if (is_multi_image_extraction) {
  97                                 num_path_components++;
  98                                 num_output_dir_path_components--;
  99                         }
 100                         file_on_disk_len = strlen(lte->file_on_disk);
 101
 102                         char buf[file_on_disk_len + 3 * num_path_components + 1];
 103                         p = &buf[0];
 104
 105                         for (i = 0; i < num_path_components; i++) {
 106                                 *p++ = '.';
 107                                 *p++ = '.';
 108                                 *p++ = '/';
 109                         }
 110                         p2 = lte->file_on_disk;
 111                         while (*p2 == '/')
 112                                 p2++;
 113                         while (num_output_dir_path_components--)
 114                                 p2 = path_next_part(p2, NULL);
 115                         strcpy(p, p2);
 116                         if (symlink(buf, output_path) != 0) {
 117                                 ERROR("Failed to symlink `%s' to `%s': %m\n",
 118                                                 buf, lte->file_on_disk);
 119                                 return WIMLIB_ERR_LINK;
 120                         }
 121
 122                 }
 123                 return 0;
 124         }
 125
 126         /* Otherwise, we must actually extract the file contents. */
 127
 128         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 129         if (out_fd == -1) {
 130                 ERROR("Failed to open the file `%s' for writing: "
 131                                 "%m\n", output_path);
 132                 return WIMLIB_ERR_OPEN;
 133         }
 134
 135         /* Extract empty file, with no lookup table entry... */
 136         if (!lte) {
 137                 DEBUG("Empty file `%s'\n", output_path);
 138                 ret = 0;
 139                 goto done;
 140         }
 141
 142         res_entry = &lte->resource_entry;
 143
 144         ret = extract_resource_to_fd(w, res_entry, out_fd,
 145                                      res_entry->original_size);
 146
 147         if (ret != 0) {
 148                 ERROR("Failed to extract resource to `%s'!\n", output_path);
 149                 goto done;
 150         }
 151
 152         /* Mark the lookup table entry to indicate this file has been extracted. */
 153         lte->out_refcnt++;
 154         FREE(lte->file_on_disk);
 155         lte->file_on_disk = STRDUP(output_path);
 156         if (lte->file_on_disk)
 157                 ret = 0;
 158         else
 159                 ret = WIMLIB_ERR_NOMEM;
 160 done:
 161         close(out_fd);
 162         return ret;
 163 }
 164
 165 /*
 166  * Extracts a directory from the WIM archive.
 167  *
 168  * @dentry:             The directory entry for the directory.
 169  * @output_path:        The path to which the directory is to be extracted to.
 170  * @return:             True on success, false on failure.
 171  */
 172 static int extract_directory(struct dentry *dentry, const char *output_path)
 173 {
 174         /* Compute the output path directory to the directory. */
 175         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0)
 176         {
 177                 switch (errno) {
 178                 case EEXIST: /* Already existing directory is OK */
 179                 case EACCES: /* We may have permissions to extract files inside
 180                                  the directory, but not for the directory
 181                                  itself. */
 182                         return 0;
 183                 default:
 184                         ERROR("Cannot create directory `%s': %m\n",
 185                                         output_path);
 186                         return WIMLIB_ERR_MKDIR;
 187                 }
 188         }
 189         return 0;
 190 }
 191
 192
 193 /*
 194  * Extracts a file or directory from the WIM archive.  For use in
 195  * for_dentry_in_tree().
 196  *
 197  * @dentry:     The dentry to extract.
 198  * @arg:        A pointer to the WIMStruct for the WIM file.
 199  */
 200 static int extract_regular_file_or_directory(struct dentry *dentry, void *arg)
 201 {
 202         WIMStruct *w = (WIMStruct*)arg;
 203         size_t len = strlen(w->output_dir);
 204         char output_path[len + dentry->full_path_utf8_len + 1];
 205
 206         if (w->verbose)
 207                 puts(dentry->full_path_utf8);
 208
 209         memcpy(output_path, w->output_dir, len);
 210         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 211         output_path[len + dentry->full_path_utf8_len] = '\0';
 212
 213
 214         if (dentry_is_regular_file(dentry)) {
 215                 return extract_regular_file(w, dentry, output_path);
 216         } else {
 217                 if (dentry_is_root(dentry)) /* Root doesn't need to be extracted. */
 218                         return 0;
 219                 else
 220                         return extract_directory(dentry, output_path);
 221         }
 222 }
 223
 224 static int extract_single_image(WIMStruct *w, int image)
 225 {
 226         DEBUG("Extracting image %d\n", image);
 227
 228         int ret;
 229         ret = wimlib_select_image(w, image);
 230         if (ret != 0)
 231                 return ret;
 232
 233         return for_dentry_in_tree(wim_root_dentry(w),
 234                                   extract_regular_file_or_directory, w);
 235 }
 236
 237
 238 /* Extracts all images from the WIM to w->output_dir, with the images placed in
 239  * subdirectories named by their image names. */
 240 static int extract_all_images(WIMStruct *w)
 241 {
 242         size_t image_name_max_len = xml_get_max_image_name_len(w);
 243         size_t output_path_len = strlen(w->output_dir);
 244         char buf[output_path_len + 1 + image_name_max_len + 1];
 245         int ret;
 246         int image;
 247
 248         DEBUG("Attempting to extract all images from `%s'\n", w->filename);
 249
 250         memcpy(buf, w->output_dir, output_path_len);
 251         buf[output_path_len] = '/';
 252         for (image = 1; image <= w->hdr.image_count; image++) {
 253                 buf[output_path_len + 1] = '\0';
 254                 strncat(buf + output_path_len + 1, wimlib_get_image_name(w, image),
 255                                 image_name_max_len);
 256                 ret = wimlib_set_output_dir(w, buf);
 257                 if (ret != 0)
 258                         goto done;
 259                 ret = extract_single_image(w, image);
 260                 if (ret != 0)
 261                         goto done;
 262         }
 263         ret = 0;
 264 done:
 265         buf[output_path_len + 1] = '\0';
 266         wimlib_set_output_dir(w, buf);
 267         return ret;
 268 }
 269
 270 /* Extracts a single image or all images from a WIM file. */
 271 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image)
 272 {
 273         if (!w->output_dir) {
 274                 ERROR("No output directory selected.\n");
 275                 return WIMLIB_ERR_NOTDIR;
 276         }
 277         if (image == WIM_ALL_IMAGES) {
 278                 w->is_multi_image_extraction = true;
 279                 return extract_all_images(w);
 280         } else {
 281                 w->is_multi_image_extraction = false;
 282                 return extract_single_image(w, image);
 283         }
 284
 285 }
 286
 287 /* Set the output directory for WIM extraction.  The directory is created using
 288  * mkdir().  Fails if directory cannot be created or already exists. */
 289 WIMLIBAPI int wimlib_set_output_dir(WIMStruct *w, const char *dir)
 290 {
 291         char *p;
 292         DEBUG("Setting output directory to `%s'\n", dir);
 293
 294         if (!dir) {
 295                 ERROR("Must specify a directory!\n");
 296                 return WIMLIB_ERR_INVALID_PARAM;
 297         }
 298         p = STRDUP(dir);
 299         if (!p) {
 300                 ERROR("Out of memory!\n");
 301                 return WIMLIB_ERR_NOMEM;
 302         }
 303
 304         if (mkdir(dir, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0) {
 305                 if (errno == EEXIST) {
 306                         DEBUG("`%s' already exists\n", dir);
 307                         goto done;
 308                 }
 309                 ERROR("Cannot create directory `%s': %m\n", dir);
 310                 FREE(p);
 311                 return WIMLIB_ERR_MKDIR;
 312         } else {
 313                 DEBUG("Created directory `%s'\n", dir);
 314         }
 315 done:
 316         FREE(w->output_dir);
 317         w->output_dir = p;
 318         return 0;
 319 }
 320
 321 WIMLIBAPI int wimlib_set_link_type(WIMStruct *w, int link_type)
 322 {
 323         switch (link_type) {
 324                 case WIM_LINK_TYPE_NONE:
 325                 case WIM_LINK_TYPE_HARD:
 326                 case WIM_LINK_TYPE_SYMBOLIC:
 327                         w->link_type = link_type;
 328                         return 0;
 329                 default:
 330                         return WIMLIB_ERR_INVALID_PARAM;
 331         }
 332 }
 333