wimlib.net Git - wimlib/blob - src/modify.c

   1 /*
   2  * modify.c
   3  *
   4  * Support for modifying WIM files with image-level operations (delete an image,
   5  * add an image, export an imagex from one WIM to another.)  There is nothing
   6  * here that lets you change individual files in the WIM; for that you will need
   7  * to look at the filesystem implementation in mount.c.
   8  */
   9
  10 /*
  11  * Copyright (C) 2012 Eric Biggers
  12  *
  13  * This file is part of wimlib, a library for working with WIM files.
  14  *
  15  * wimlib is free software; you can redistribute it and/or modify it under the
  16  * terms of the GNU Lesser General Public License as published by the Free
  17  * Software Foundation; either version 2.1 of the License, or (at your option)
  18  * any later version.
  19  *
  20  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  21  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  22  * A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  23  * details.
  24  *
  25  * You should have received a copy of the GNU Lesser General Public License
  26  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  27  */
  28
  29 #include "wimlib_internal.h"
  30 #include "util.h"
  31 #include "sha1.h"
  32 #include "dentry.h"
  33 #include "xml.h"
  34 #include "lookup_table.h"
  35 #include <sys/stat.h>
  36 #include <dirent.h>
  37 #include <string.h>
  38 #include <errno.h>
  39 #include <unistd.h>
  40
  41 /** Private flag: Used to mark that we currently adding the root directory of
  42  * the WIM. */
  43 #define WIMLIB_ADD_IMAGE_FLAG_ROOT 0x80000000
  44
  45 void destroy_image_metadata(struct image_metadata *imd,struct lookup_table *lt)
  46 {
  47         free_dentry_tree(imd->root_dentry, lt);
  48         free_security_data(imd->security_data);
  49         free_link_group_table(imd->lgt);
  50
  51         /* Get rid of the lookup table entry for this image's metadata resource
  52          * */
  53         if (lt)
  54                 lookup_table_remove(lt, imd->metadata_lte);
  55 }
  56
  57 /*
  58  * Recursively builds a dentry tree from a directory tree on disk, outside the
  59  * WIM file.
  60  *
  61  * @root:  A dentry that has already been created for the root of the dentry
  62  *         tree.
  63  * @root_disk_path:  The path to the root of the tree on disk.
  64  * @lookup_table: The lookup table for the WIM file.  For each file added to the
  65  *              dentry tree being built, an entry is added to the lookup table,
  66  *              unless an identical file is already in the lookup table.  These
  67  *              lookup table entries that are added point to the file on disk.
  68  *
  69  * @return:     0 on success, nonzero on failure.  It is a failure if any of
  70  *              the files cannot be `stat'ed, or if any of the needed
  71  *              directories cannot be opened or read.  Failure to add the files
  72  *              to the WIM may still occur later when trying to actually read
  73  *              the regular files in the tree into the WIM as file resources.
  74  */
  75 static int build_dentry_tree(struct dentry *root, const char *root_disk_path,
  76                              struct lookup_table* lookup_table,
  77                              int add_flags)
  78 {
  79         DEBUG("%s", root_disk_path);
  80         struct stat root_stbuf;
  81         int ret = 0;
  82         int (*stat_fn)(const char *restrict, struct stat *restrict);
  83
  84         if (add_flags & WIMLIB_ADD_IMAGE_FLAG_DEREFERENCE)
  85                 stat_fn = stat;
  86         else
  87                 stat_fn = lstat;
  88
  89
  90         ret = (*stat_fn)(root_disk_path, &root_stbuf);
  91         if (ret != 0) {
  92                 ERROR_WITH_ERRNO("Failed to stat `%s'", root_disk_path);
  93                 return WIMLIB_ERR_STAT;
  94         }
  95
  96         if ((add_flags & WIMLIB_ADD_IMAGE_FLAG_ROOT) &&
  97               !S_ISDIR(root_stbuf.st_mode)) {
  98                 ERROR("`%s' is not a directory", root_disk_path);
  99                 return WIMLIB_ERR_NOTDIR;
 100         }
 101         if (!S_ISREG(root_stbuf.st_mode) && !S_ISDIR(root_stbuf.st_mode)
 102             && !S_ISLNK(root_stbuf.st_mode)) {
 103                 ERROR("`%s' is not a regular file, directory, or symbolic link.");
 104                 return WIMLIB_ERR_SPECIAL_FILE;
 105         }
 106         stbuf_to_dentry(&root_stbuf, root);
 107         add_flags &= ~WIMLIB_ADD_IMAGE_FLAG_ROOT;
 108         root->resolved = true;
 109
 110         if (dentry_is_directory(root)) {
 111                 /* Open the directory on disk */
 112                 DIR *dir;
 113                 struct dirent *p;
 114                 struct dentry *child;
 115
 116                 dir = opendir(root_disk_path);
 117                 if (!dir) {
 118                         ERROR_WITH_ERRNO("Failed to open the directory `%s'",
 119                                          root_disk_path);
 120                         return WIMLIB_ERR_OPEN;
 121                 }
 122
 123                 /* Buffer for names of files in directory. */
 124                 size_t len = strlen(root_disk_path);
 125                 char name[len + 1 + FILENAME_MAX + 1];
 126                 memcpy(name, root_disk_path, len);
 127                 name[len] = '/';
 128
 129                 /* Create a dentry for each entry in the directory on disk, and recurse
 130                  * to any subdirectories. */
 131                 while ((p = readdir(dir)) != NULL) {
 132                         if (p->d_name[0] == '.' && (p->d_name[1] == '\0'
 133                               || (p->d_name[1] == '.' && p->d_name[2] == '\0')))
 134                                         continue;
 135                         strcpy(name + len + 1, p->d_name);
 136                         child = new_dentry(p->d_name);
 137                         if (!child)
 138                                 return WIMLIB_ERR_NOMEM;
 139                         ret = build_dentry_tree(child, name, lookup_table,
 140                                                 add_flags);
 141                         link_dentry(child, root);
 142                         if (ret != 0)
 143                                 break;
 144                 }
 145                 closedir(dir);
 146         } else if (dentry_is_symlink(root)) {
 147                 /* Archiving a symbolic link */
 148                 size_t symlink_buf_len;
 149                 char deref_name_buf[4096];
 150                 ssize_t deref_name_len;
 151
 152                 deref_name_len = readlink(root_disk_path, deref_name_buf,
 153                                           sizeof(deref_name_buf) - 1);
 154                 if (deref_name_len == -1) {
 155                         ERROR_WITH_ERRNO("Failed to read target of "
 156                                          "symbolic link `%s'", root_disk_path);
 157                         return WIMLIB_ERR_READLINK;
 158                 }
 159                 deref_name_buf[deref_name_len] = '\0';
 160                 DEBUG("Read symlink `%s'", deref_name_buf);
 161                 ret = dentry_set_symlink(root, deref_name_buf,
 162                                          lookup_table, NULL);
 163         } else {
 164                 /* Regular file */
 165                 struct lookup_table_entry *lte;
 166                 u8 hash[SHA1_HASH_SIZE];
 167
 168                 /* For each regular file, we must check to see if the file is in
 169                  * the lookup table already; if it is, we increment its refcnt;
 170                  * otherwise, we create a new lookup table entry and insert it.
 171                  * */
 172                 ret = sha1sum(root_disk_path, hash);
 173                 if (ret != 0)
 174                         return ret;
 175
 176                 lte = __lookup_resource(lookup_table, hash);
 177                 if (lte) {
 178                         lte->refcnt++;
 179                         DEBUG("Add lte reference %u for `%s'", lte->refcnt,
 180                               root_disk_path);
 181                 } else {
 182                         char *file_on_disk = STRDUP(root_disk_path);
 183                         if (!file_on_disk) {
 184                                 ERROR("Failed to allocate memory for file path");
 185                                 return WIMLIB_ERR_NOMEM;
 186                         }
 187                         lte = new_lookup_table_entry();
 188                         if (!lte) {
 189                                 FREE(file_on_disk);
 190                                 return WIMLIB_ERR_NOMEM;
 191                         }
 192                         lte->file_on_disk = file_on_disk;
 193                         lte->resource_location = RESOURCE_IN_FILE_ON_DISK;
 194                         lte->resource_entry.original_size = root_stbuf.st_size;
 195                         lte->resource_entry.size = root_stbuf.st_size;
 196                         copy_hash(lte->hash, hash);
 197                         lookup_table_insert(lookup_table, lte);
 198                 }
 199                 root->lte = lte;
 200         }
 201         return ret;
 202 }
 203
 204 struct wim_pair {
 205         WIMStruct *src_wim;
 206         WIMStruct *dest_wim;
 207 };
 208
 209 /*
 210  * This function takes in a dentry that was previously located only in image(s)
 211  * in @src_wim, but now is being added to @dest_wim. If there is in fact already a
 212  * lookup table entry for this file in the lookup table of the destination WIM
 213  * file, we simply increment its reference count.  Otherwise, a new lookup table
 214  * entry is created that references the location of the file resource in the
 215  * source WIM file through the other_wim_fp field of the lookup table entry.
 216  */
 217 static int add_lte_to_dest_wim(struct dentry *dentry, void *arg)
 218 {
 219         WIMStruct *src_wim, *dest_wim;
 220
 221         src_wim = ((struct wim_pair*)arg)->src_wim;
 222         dest_wim = ((struct wim_pair*)arg)->dest_wim;
 223
 224         wimlib_assert(!dentry->resolved);
 225
 226         for (unsigned i = 0; i < (unsigned)dentry->num_ads + 1; i++) {
 227                 struct lookup_table_entry *src_lte, *dest_lte;
 228                 src_lte = dentry_stream_lte_unresolved(dentry, i,
 229                                                        src_wim->lookup_table);
 230                 if (!src_lte)
 231                         continue;
 232                 dest_lte = dentry_stream_lte_unresolved(dentry, i,
 233                                                         dest_wim->lookup_table);
 234                 if (dest_lte) {
 235                         dest_lte->refcnt++;
 236                 } else {
 237                         dest_lte = new_lookup_table_entry();
 238                         if (!dest_lte)
 239                                 return WIMLIB_ERR_NOMEM;
 240                         dest_lte->wim = src_wim;
 241                         memcpy(&dest_lte->resource_entry,
 242                                &src_lte->resource_entry,
 243                                sizeof(struct resource_entry));
 244                         copy_hash(dest_lte->hash,
 245                                   dentry_stream_hash_unresolved(dentry, i));
 246                         lookup_table_insert(dest_wim->lookup_table, dest_lte);
 247                 }
 248         }
 249         return 0;
 250 }
 251
 252 /*
 253  * Adds an image (given by its dentry tree) to the image metadata array of a WIM
 254  * file, adds an entry to the lookup table for the image metadata, updates the
 255  * image count in the header, and selects the new image.
 256  *
 257  * Does not update the XML data.
 258  *
 259  * @w:            The WIMStruct for the WIM file.
 260  * @root_dentry:  The root of the directory tree for the image.
 261  */
 262 static int add_new_dentry_tree(WIMStruct *w, struct dentry *root_dentry)
 263 {
 264         struct lookup_table_entry *metadata_lte;
 265         struct image_metadata *imd;
 266         struct image_metadata *new_imd;
 267         struct wim_security_data *sd;
 268         struct link_group_table *lgt;
 269
 270         DEBUG("Reallocating image metadata array for image_count = %u",
 271               w->hdr.image_count + 1);
 272         imd = CALLOC((w->hdr.image_count + 1), sizeof(struct image_metadata));
 273
 274         if (!imd) {
 275                 ERROR("Failed to allocate memory for new image metadata array");
 276                 return WIMLIB_ERR_NOMEM;
 277         }
 278
 279         memcpy(imd, w->image_metadata,
 280                w->hdr.image_count * sizeof(struct image_metadata));
 281
 282         metadata_lte = new_lookup_table_entry();
 283         if (!metadata_lte)
 284                 goto out_free_imd;
 285         sd = CALLOC(1, sizeof(struct wim_security_data));
 286         if (!sd)
 287                 goto out_free_metadata_lte;
 288         sd->refcnt = 1;
 289         sd->total_length = 8;
 290
 291         lgt = new_link_group_table(9001);
 292         if (!lgt)
 293                 goto out_free_security_data;
 294
 295         metadata_lte->resource_entry.flags = WIM_RESHDR_FLAG_METADATA;
 296         random_hash(metadata_lte->hash);
 297         lookup_table_insert(w->lookup_table, metadata_lte);
 298
 299         new_imd = &imd[w->hdr.image_count];
 300
 301         new_imd->root_dentry    = root_dentry;
 302         new_imd->metadata_lte   = metadata_lte;
 303         new_imd->security_data  = sd;
 304         new_imd->lgt            = lgt;
 305         new_imd->modified       = true;
 306
 307         FREE(w->image_metadata);
 308         w->image_metadata       = imd;
 309         w->hdr.image_count++;
 310
 311         /* Change the current image to the new one. */
 312         return wimlib_select_image(w, w->hdr.image_count);
 313 out_free_security_data:
 314         FREE(sd);
 315 out_free_metadata_lte:
 316         FREE(metadata_lte);
 317 out_free_imd:
 318         FREE(imd);
 319         return WIMLIB_ERR_NOMEM;
 320
 321 }
 322
 323 /*
 324  * Copies an image, or all the images, from a WIM file, into another WIM file.
 325  */
 326 WIMLIBAPI int wimlib_export_image(WIMStruct *src_wim,
 327                                   int src_image,
 328                                   WIMStruct *dest_wim,
 329                                   const char *dest_name,
 330                                   const char *dest_description,
 331                                   int flags)
 332 {
 333         int i;
 334         int ret;
 335         struct dentry *root;
 336         struct wim_pair wims;
 337
 338         if (src_image == WIM_ALL_IMAGES) {
 339                 if (src_wim->hdr.image_count > 1) {
 340
 341                         /* multi-image export. */
 342
 343                         if ((flags & WIMLIB_EXPORT_FLAG_BOOT) &&
 344                               (src_wim->hdr.boot_idx == 0))
 345                         {
 346                                 /* Specifying the boot flag on a multi-image
 347                                  * source WIM makes the boot index default to
 348                                  * the bootable image in the source WIM.  It is
 349                                  * an error if there is no such bootable image.
 350                                  * */
 351                                 ERROR("Cannot specify `boot' flag when "
 352                                       "exporting multiple images from a WIM "
 353                                       "with no bootable images");
 354                                 return WIMLIB_ERR_INVALID_PARAM;
 355                         }
 356                         if (dest_name || dest_description) {
 357                                 ERROR("Image name or image description was "
 358                                       "specified, but we are exporting "
 359                                       "multiple images");
 360                                 return WIMLIB_ERR_INVALID_PARAM;
 361                         }
 362                         for (i = 1; i <= src_wim->hdr.image_count; i++) {
 363                                 int export_flags = flags;
 364
 365                                 if (i != src_wim->hdr.boot_idx)
 366                                         export_flags &= ~WIMLIB_EXPORT_FLAG_BOOT;
 367
 368                                 ret = wimlib_export_image(src_wim, i, dest_wim,
 369                                                           NULL,
 370                                                           dest_description,
 371                                                           export_flags);
 372                                 if (ret != 0)
 373                                         return ret;
 374                         }
 375                         return 0;
 376                 } else {
 377                         src_image = 1;
 378                 }
 379         }
 380
 381         ret = wimlib_select_image(src_wim, src_image);
 382         if (ret != 0) {
 383                 ERROR("Could not select image %d from the WIM `%s' "
 384                       "to export it", src_image, src_wim->filename);
 385                 return ret;
 386         }
 387
 388         if (!dest_name) {
 389                 dest_name = wimlib_get_image_name(src_wim, src_image);
 390                 DEBUG("Using name `%s' for source image %d",
 391                       dest_name, src_image);
 392         }
 393
 394         DEBUG("Exporting image %d from `%s'", src_image, src_wim->filename);
 395
 396         if (wimlib_image_name_in_use(dest_wim, dest_name)) {
 397                 ERROR("There is already an image named `%s' in the "
 398                       "destination WIM", dest_name);
 399                 return WIMLIB_ERR_IMAGE_NAME_COLLISION;
 400         }
 401
 402
 403         /* Cleaning up here on failure would be hard.  For example, we could
 404          * fail to allocate memory in add_lte_to_dest_wim(),
 405          * leaving the lookup table entries in the destination WIM in an
 406          * inconsistent state.  Until these issues can be resolved,
 407          * wimlib_export_image() is documented as leaving dest_wim is an
 408          * indeterminate state.  */
 409         root = wim_root_dentry(src_wim);
 410         for_dentry_in_tree(root, increment_dentry_refcnt, NULL);
 411         wims.src_wim = src_wim;
 412         wims.dest_wim = dest_wim;
 413         ret = for_dentry_in_tree(root, add_lte_to_dest_wim, &wims);
 414         if (ret != 0)
 415                 return ret;
 416         ret = add_new_dentry_tree(dest_wim, root);
 417         if (ret != 0)
 418                 return ret;
 419         /* Bring over old security data */
 420         struct wim_security_data *sd = wim_security_data(src_wim);
 421         struct image_metadata *new_imd = wim_get_current_image_metadata(dest_wim);
 422         wimlib_assert(sd);
 423         free_security_data(new_imd->security_data);
 424         new_imd->security_data = sd;
 425         sd->refcnt++;
 426
 427         if (flags & WIMLIB_EXPORT_FLAG_BOOT) {
 428                 DEBUG("Setting boot_idx to %d", dest_wim->hdr.image_count);
 429                 dest_wim->hdr.boot_idx = dest_wim->hdr.image_count;
 430         }
 431
 432         return xml_export_image(src_wim->wim_info, src_image, &dest_wim->wim_info,
 433                                 dest_name, dest_description);
 434 }
 435
 436 /*
 437  * Deletes an image from the WIM.
 438  */
 439 WIMLIBAPI int wimlib_delete_image(WIMStruct *w, int image)
 440 {
 441         int num_images;
 442         int i;
 443         int ret;
 444
 445         if (image == WIM_ALL_IMAGES) {
 446                 num_images = w->hdr.image_count;
 447                 for (i = 1; i <= num_images; i++) {
 448                         /* Always delete the first image, since by the end
 449                          * there won't be any more than that!  */
 450                         ret = wimlib_delete_image(w, 1);
 451                         if (ret != 0)
 452                                 return ret;
 453                 }
 454                 return 0;
 455         }
 456
 457         DEBUG("Deleting image %d", image);
 458
 459         /* Even if the dentry tree is not allocated, we must select it (and
 460          * therefore allocate it) so that we can decrement the reference counts
 461          * in the lookup table.  */
 462         ret = wimlib_select_image(w, image);
 463         if (ret != 0)
 464                 return ret;
 465
 466         /* Free the dentry tree, any lookup table entries that have their
 467          * refcnt decremented to 0, and the security data. */
 468         destroy_image_metadata(wim_get_current_image_metadata(w),
 469                                w->lookup_table);
 470
 471         /* Get rid of the empty slot in the image metadata array. */
 472         memmove(&w->image_metadata[image - 1], &w->image_metadata[image],
 473                 (w->hdr.image_count - image) * sizeof(struct image_metadata));
 474
 475         /* Decrement the image count. */
 476         if (--w->hdr.image_count == 0) {
 477                 FREE(w->image_metadata);
 478                 w->image_metadata = NULL;
 479         }
 480
 481         /* Fix the boot index. */
 482         if (w->hdr.boot_idx == image)
 483                 w->hdr.boot_idx = 0;
 484         else if (w->hdr.boot_idx > image)
 485                 w->hdr.boot_idx--;
 486
 487         w->current_image = WIM_NO_IMAGE;
 488
 489         /* Remove the image from the XML information. */
 490         xml_delete_image(&w->wim_info, image);
 491         return 0;
 492 }
 493
 494 /*
 495  * Adds an image to a WIM file from a directory tree on disk.
 496  */
 497 WIMLIBAPI int wimlib_add_image(WIMStruct *w, const char *dir,
 498                                const char *name, const char *description,
 499                                const char *flags_element, int flags)
 500 {
 501         struct dentry *root_dentry;
 502         struct image_metadata *imd;
 503         int ret;
 504
 505         DEBUG("Adding dentry tree from dir `%s'.", dir);
 506
 507         if (!name || !*name) {
 508                 ERROR("Must specify a non-empty string for the image name");
 509                 return WIMLIB_ERR_INVALID_PARAM;
 510         }
 511         if (!dir) {
 512                 ERROR("Must specify the name of a directory");
 513                 return WIMLIB_ERR_INVALID_PARAM;
 514         }
 515
 516         if (wimlib_image_name_in_use(w, name)) {
 517                 ERROR("There is already an image named \"%s\" in `%s'",
 518                       name, w->filename);
 519                 return WIMLIB_ERR_IMAGE_NAME_COLLISION;
 520         }
 521
 522         DEBUG("Creating root dentry.");
 523
 524         root_dentry = new_dentry("");
 525         if (!root_dentry)
 526                 return WIMLIB_ERR_NOMEM;
 527
 528         DEBUG("Building dentry tree.");
 529         ret = build_dentry_tree(root_dentry, dir, w->lookup_table,
 530                                 flags | WIMLIB_ADD_IMAGE_FLAG_ROOT);
 531
 532         if (ret != 0) {
 533                 ERROR("Failed to build dentry tree for `%s'", dir);
 534                 goto out_free_dentry_tree;
 535         }
 536
 537         DEBUG("Calculating full paths of dentries.");
 538         ret = for_dentry_in_tree(root_dentry, calculate_dentry_full_path, NULL);
 539         if (ret != 0)
 540                 goto out_free_dentry_tree;
 541
 542         ret = add_new_dentry_tree(w, root_dentry);
 543         if (ret != 0)
 544                 goto out_free_dentry_tree;
 545
 546         DEBUG("Inserting dentries into hard link group table");
 547         ret = for_dentry_in_tree(root_dentry, link_group_table_insert,
 548                                  w->image_metadata[w->hdr.image_count - 1].lgt);
 549         if (ret != 0)
 550                 goto out_destroy_imd;
 551         DEBUG("Assigning hard link groups");
 552         assign_link_groups(w->image_metadata[w->hdr.image_count - 1].lgt);
 553
 554         if (flags & WIMLIB_ADD_IMAGE_FLAG_BOOT)
 555                 wimlib_set_boot_idx(w, w->hdr.image_count);
 556
 557         ret = xml_add_image(w, root_dentry, name, description, flags_element);
 558         if (ret != 0)
 559                 goto out_destroy_imd;
 560
 561         return 0;
 562 out_destroy_imd:
 563         destroy_image_metadata(&w->image_metadata[w->hdr.image_count - 1],
 564                                w->lookup_table);
 565         w->hdr.image_count--;
 566         return ret;
 567 out_free_dentry_tree:
 568         free_dentry_tree(root_dentry, w->lookup_table);
 569         return ret;
 570 }