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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("Failed to hard link `%s' to `%s': %m\n",
  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(w->output_dir);
  97
  98                         if (is_multi_image_extraction) {
  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("Failed to symlink `%s' to `%s': %m\n",
 120                                                 buf, lte->file_on_disk);
 121                                 return WIMLIB_ERR_LINK;
 122                         }
 123
 124                 }
 125                 return 0;
 126         }
 127
 128         /* Otherwise, we must actually extract the file contents. */
 129
 130         out_fd = open(output_path, O_WRONLY | O_CREAT | O_TRUNC, 0644);
 131         if (out_fd == -1) {
 132                 ERROR("Failed to open the file `%s' for writing: "
 133                                 "%m\n", output_path);
 134                 return WIMLIB_ERR_OPEN;
 135         }
 136
 137         /* Extract empty file, with no lookup table entry... */
 138         if (!lte) {
 139                 DEBUG("Empty file `%s'\n", output_path);
 140                 ret = 0;
 141                 goto done;
 142         }
 143
 144         res_entry = &lte->resource_entry;
 145
 146         ret = extract_resource_to_fd(w, res_entry, out_fd,
 147                                      res_entry->original_size);
 148
 149         if (ret != 0) {
 150                 ERROR("Failed to extract resource to `%s'!\n", output_path);
 151                 goto done;
 152         }
 153
 154         /* Mark the lookup table entry to indicate this file has been extracted. */
 155         lte->out_refcnt++;
 156         FREE(lte->file_on_disk);
 157         lte->file_on_disk = STRDUP(output_path);
 158         if (lte->file_on_disk)
 159                 ret = 0;
 160         else
 161                 ret = WIMLIB_ERR_NOMEM;
 162 done:
 163         close(out_fd);
 164         return ret;
 165 }
 166
 167 /*
 168  * Extracts a directory from the WIM archive.
 169  *
 170  * @dentry:             The directory entry for the directory.
 171  * @output_path:        The path to which the directory is to be extracted to.
 172  * @return:             True on success, false on failure.
 173  */
 174 static int extract_directory(struct dentry *dentry, const char *output_path)
 175 {
 176         /* Compute the output path directory to the directory. */
 177         if (mkdir(output_path, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0)
 178         {
 179                 switch (errno) {
 180                 case EEXIST: /* Already existing directory is OK */
 181                 case EACCES: /* We may have permissions to extract files inside
 182                                  the directory, but not for the directory
 183                                  itself. */
 184                         return 0;
 185                 default:
 186                         ERROR("Cannot create directory `%s': %m\n",
 187                                         output_path);
 188                         return WIMLIB_ERR_MKDIR;
 189                 }
 190         }
 191         return 0;
 192 }
 193
 194
 195 /*
 196  * Extracts a file or directory from the WIM archive.  For use in
 197  * for_dentry_in_tree().
 198  *
 199  * @dentry:     The dentry to extract.
 200  * @arg:        A pointer to the WIMStruct for the WIM file.
 201  */
 202 static int extract_regular_file_or_directory(struct dentry *dentry, void *arg)
 203 {
 204         WIMStruct *w = (WIMStruct*)arg;
 205         size_t len = strlen(w->output_dir);
 206         char output_path[len + dentry->full_path_utf8_len + 1];
 207
 208         if (w->verbose)
 209                 puts(dentry->full_path_utf8);
 210
 211         memcpy(output_path, w->output_dir, len);
 212         memcpy(output_path + len, dentry->full_path_utf8, dentry->full_path_utf8_len);
 213         output_path[len + dentry->full_path_utf8_len] = '\0';
 214
 215
 216         if (dentry_is_regular_file(dentry)) {
 217                 return extract_regular_file(w, dentry, output_path);
 218         } else {
 219                 if (dentry_is_root(dentry)) /* Root doesn't need to be extracted. */
 220                         return 0;
 221                 else
 222                         return extract_directory(dentry, output_path);
 223         }
 224 }
 225
 226 static int extract_single_image(WIMStruct *w, int image)
 227 {
 228         DEBUG("Extracting image %d\n", image);
 229
 230         int ret;
 231         ret = wimlib_select_image(w, image);
 232         if (ret != 0)
 233                 return ret;
 234
 235         return for_dentry_in_tree(wim_root_dentry(w),
 236                                   extract_regular_file_or_directory, w);
 237 }
 238
 239
 240 /* Extracts all images from the WIM to w->output_dir, with the images placed in
 241  * subdirectories named by their image names. */
 242 static int extract_all_images(WIMStruct *w)
 243 {
 244         size_t image_name_max_len = max(xml_get_max_image_name_len(w), 20);
 245         size_t output_path_len = strlen(w->output_dir);
 246         char buf[output_path_len + 1 + image_name_max_len + 1];
 247         int ret;
 248         int image;
 249         const char *image_name;
 250
 251         DEBUG("Attempting to extract all images from `%s'\n", w->filename);
 252
 253         memcpy(buf, w->output_dir, output_path_len);
 254         buf[output_path_len] = '/';
 255         for (image = 1; image <= w->hdr.image_count; image++) {
 256                 buf[output_path_len + 1] = '\0';
 257
 258                 image_name = wimlib_get_image_name(w, image);
 259                 if (*image_name) {
 260                         strncat(buf + output_path_len + 1, image_name,
 261                                 image_name_max_len);
 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         ret = 0;
 274 done:
 275         buf[output_path_len + 1] = '\0';
 276         wimlib_set_output_dir(w, buf);
 277         return ret;
 278 }
 279
 280 /* Extracts a single image or all images from a WIM file. */
 281 WIMLIBAPI int wimlib_extract_image(WIMStruct *w, int image)
 282 {
 283         if (!w->output_dir) {
 284                 ERROR("No output directory selected.\n");
 285                 return WIMLIB_ERR_NOTDIR;
 286         }
 287         if (image == WIM_ALL_IMAGES) {
 288                 w->is_multi_image_extraction = true;
 289                 return extract_all_images(w);
 290         } else {
 291                 w->is_multi_image_extraction = false;
 292                 return extract_single_image(w, image);
 293         }
 294
 295 }
 296
 297 /* Set the output directory for WIM extraction.  The directory is created using
 298  * mkdir().  Fails if directory cannot be created or already exists. */
 299 WIMLIBAPI int wimlib_set_output_dir(WIMStruct *w, const char *dir)
 300 {
 301         char *p;
 302         DEBUG("Setting output directory to `%s'\n", dir);
 303
 304         if (!dir) {
 305                 ERROR("Must specify a directory!\n");
 306                 return WIMLIB_ERR_INVALID_PARAM;
 307         }
 308         p = STRDUP(dir);
 309         if (!p) {
 310                 ERROR("Out of memory!\n");
 311                 return WIMLIB_ERR_NOMEM;
 312         }
 313
 314         if (mkdir(dir, S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH) != 0) {
 315                 if (errno == EEXIST) {
 316                         DEBUG("`%s' already exists\n", dir);
 317                         goto done;
 318                 }
 319                 ERROR("Cannot create directory `%s': %m\n", dir);
 320                 FREE(p);
 321                 return WIMLIB_ERR_MKDIR;
 322         } else {
 323                 DEBUG("Created directory `%s'\n", dir);
 324         }
 325 done:
 326         FREE(w->output_dir);
 327         w->output_dir = p;
 328         return 0;
 329 }
 330
 331 WIMLIBAPI int wimlib_set_link_type(WIMStruct *w, int link_type)
 332 {
 333         switch (link_type) {
 334                 case WIM_LINK_TYPE_NONE:
 335                 case WIM_LINK_TYPE_HARD:
 336                 case WIM_LINK_TYPE_SYMBOLIC:
 337                         w->link_type = link_type;
 338                         return 0;
 339                 default:
 340                         return WIMLIB_ERR_INVALID_PARAM;
 341         }
 342 }
 343