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   1 /*
   2  * lookup_table.c
   3  *
   4  * Lookup table, implemented as a hash table, that maps dentries to file
   5  * resources.
   6  */
   7
   8 /*
   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 "lookup_table.h"
  29 #include "io.h"
  30 #include <errno.h>
  31
  32 struct lookup_table *new_lookup_table(size_t capacity)
  33 {
  34         struct lookup_table *table;
  35         struct hlist_head *array;
  36
  37         table = MALLOC(sizeof(struct lookup_table));
  38         if (!table)
  39                 goto err;
  40         array = CALLOC(capacity, sizeof(array[0]));
  41         if (!array) {
  42                 FREE(table);
  43                 goto err;
  44         }
  45         table->num_entries = 0;
  46         table->capacity = capacity;
  47         table->array = array;
  48         return table;
  49 err:
  50         ERROR("Failed to allocate memory for lookup table with capacity %zu",
  51               capacity);
  52         return NULL;
  53 }
  54
  55 struct lookup_table_entry *new_lookup_table_entry(WIMStruct *wim)
  56 {
  57         struct lookup_table_entry *lte;
  58
  59         lte = CALLOC(1, sizeof(struct lookup_table_entry));
  60         if (!lte) {
  61                 ERROR("Out of memory (tried to allocate %zu bytes for "
  62                       "lookup table entry)",
  63                       sizeof(struct lookup_table_entry));
  64                 return NULL;
  65         }
  66
  67         lte->part_number  = 1;
  68         lte->refcnt       = 1;
  69         lte->wim          = wim;
  70         INIT_LIST_HEAD(&lte->lte_group_list);
  71         return lte;
  72 }
  73
  74 void free_lookup_table_entry(struct lookup_table_entry *lte)
  75 {
  76         if (lte) {
  77                 if (lte->staging_list.next)
  78                         list_del(&lte->staging_list);
  79                 if (lte->resource_location != RESOURCE_IN_WIM &&
  80                     lte->resource_location != RESOURCE_NONEXISTENT)
  81                         FREE(lte->file_on_disk);
  82                 FREE(lte);
  83         }
  84 }
  85
  86 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
  87                                       void *ignore)
  88 {
  89         free_lookup_table_entry(entry);
  90         return 0;
  91 }
  92
  93
  94 void free_lookup_table(struct lookup_table *table)
  95 {
  96         DEBUG("Freeing lookup table");
  97         if (table) {
  98                 if (table->array) {
  99                         for_lookup_table_entry(table,
 100                                                do_free_lookup_table_entry,
 101                                                NULL);
 102                         FREE(table->array);
 103                 }
 104                 FREE(table);
 105         }
 106 }
 107
 108 /*
 109  * Inserts an entry into the lookup table.
 110  *
 111  * @table:      A pointer to the lookup table.
 112  * @entry:      A pointer to the entry to insert.
 113  */
 114 void lookup_table_insert(struct lookup_table *table,
 115                          struct lookup_table_entry *lte)
 116 {
 117         size_t i = lte->hash_short % table->capacity;
 118         hlist_add_head(&lte->hash_list, &table->array[i]);
 119
 120         /* XXX Make the table grow when too many entries have been inserted. */
 121         table->num_entries++;
 122 }
 123
 124
 125
 126 /* Decrements the reference count for the lookup table entry @lte.  If its
 127  * reference count reaches 0, it is unlinked from the lookup table.  If,
 128  * furthermore, the entry has no opened file descriptors associated with it, the
 129  * entry is freed.  */
 130 struct lookup_table_entry *
 131 lte_decrement_refcnt(struct lookup_table_entry *lte, struct lookup_table *table)
 132 {
 133         if (lte) {
 134                 wimlib_assert(lte->refcnt);
 135                 if (--lte->refcnt == 0) {
 136                         lookup_table_unlink(table, lte);
 137                         if (lte->num_opened_fds == 0) {
 138                                 free_lookup_table_entry(lte);
 139                                 lte = NULL;
 140                         }
 141                 }
 142         }
 143         return lte;
 144 }
 145
 146 /*
 147  * Calls a function on all the entries in the lookup table.  Stop early and
 148  * return nonzero if any call to the function returns nonzero.
 149  */
 150 int for_lookup_table_entry(struct lookup_table *table,
 151                            int (*visitor)(struct lookup_table_entry *, void *),
 152                            void *arg)
 153 {
 154         struct lookup_table_entry *lte;
 155         struct hlist_node *pos, *tmp;
 156         int ret;
 157
 158         for (size_t i = 0; i < table->capacity; i++) {
 159                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 160                                           hash_list)
 161                 {
 162                         ret = visitor(lte, arg);
 163                         if (ret != 0)
 164                                 return ret;
 165                 }
 166         }
 167         return 0;
 168 }
 169
 170
 171 /*
 172  * Reads the lookup table from a WIM file.
 173  */
 174 int read_lookup_table(WIMStruct *w)
 175 {
 176         u64    num_entries;
 177         u8     buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 178         int    ret;
 179         struct lookup_table *table;
 180
 181         DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
 182               w->hdr.lookup_table_res_entry.offset,
 183               w->hdr.lookup_table_res_entry.original_size);
 184
 185         if (fseeko(w->fp, w->hdr.lookup_table_res_entry.offset, SEEK_SET) != 0) {
 186                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
 187                                  "lookup table",
 188                                  w->hdr.lookup_table_res_entry.offset);
 189                 return WIMLIB_ERR_READ;
 190         }
 191
 192         num_entries = w->hdr.lookup_table_res_entry.original_size /
 193                       WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
 194         table = new_lookup_table(num_entries * 2 + 1);
 195         if (!table)
 196                 return WIMLIB_ERR_NOMEM;
 197
 198         while (num_entries--) {
 199                 const u8 *p;
 200                 struct lookup_table_entry *cur_entry, *duplicate_entry;
 201
 202                 if (fread(buf, 1, sizeof(buf), w->fp) != sizeof(buf)) {
 203                         if (feof(w->fp)) {
 204                                 ERROR("Unexpected EOF in WIM lookup table!");
 205                         } else {
 206                                 ERROR_WITH_ERRNO("Error reading WIM lookup "
 207                                                  "table");
 208                         }
 209                         ret = WIMLIB_ERR_READ;
 210                         goto out;
 211                 }
 212                 cur_entry = new_lookup_table_entry(w);
 213                 if (!cur_entry) {
 214                         ret = WIMLIB_ERR_NOMEM;
 215                         goto out;
 216                 }
 217                 cur_entry->wim = w;
 218                 cur_entry->resource_location = RESOURCE_IN_WIM;
 219
 220                 p = get_resource_entry(buf, &cur_entry->resource_entry);
 221                 p = get_u16(p, &cur_entry->part_number);
 222                 p = get_u32(p, &cur_entry->refcnt);
 223                 p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
 224
 225                 duplicate_entry = __lookup_resource(table, cur_entry->hash);
 226                 if (duplicate_entry) {
 227                         ERROR("The WIM lookup table contains two entries with the "
 228                               "same SHA1 message digest!");
 229                         ERROR("The first entry is:");
 230                         print_lookup_table_entry(duplicate_entry);
 231                         ERROR("The second entry is:");
 232                         print_lookup_table_entry(cur_entry);
 233                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 234                         goto out;
 235                 }
 236                 lookup_table_insert(table, cur_entry);
 237
 238                 if (!(cur_entry->resource_entry.flags & WIM_RESHDR_FLAG_COMPRESSED)
 239                     && (cur_entry->resource_entry.size !=
 240                       cur_entry->resource_entry.original_size))
 241                 {
 242                         ERROR("Found uncompressed resource with original size "
 243                               "not the same as compressed size");
 244                         ERROR("The lookup table entry for the resource is as follows:");
 245                         print_lookup_table_entry(cur_entry);
 246                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 247                         goto out;
 248                 }
 249         }
 250         DEBUG("Done reading lookup table.");
 251         w->lookup_table = table;
 252         return 0;
 253 out:
 254         free_lookup_table(table);
 255         return ret;
 256 }
 257
 258
 259 /*
 260  * Writes a lookup table entry to the output file.
 261  */
 262 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
 263 {
 264         FILE *out;
 265         u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 266         u8 *p;
 267
 268         out = __out;
 269
 270         /* do not write lookup table entries for empty files */
 271         if (lte->output_resource_entry.original_size == 0)
 272                 return 0;
 273
 274         /* Don't write entries that have not had file resources or metadata
 275          * resources written for them. */
 276         if (lte->out_refcnt == 0)
 277                 return 0;
 278
 279         if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
 280                 DEBUG("Writing metadata entry at %lu (orig size = %zu)",
 281                       ftello(out), lte->output_resource_entry.original_size);
 282
 283         p = put_resource_entry(buf, &lte->output_resource_entry);
 284         p = put_u16(p, lte->part_number);
 285         p = put_u32(p, lte->out_refcnt);
 286         p = put_bytes(p, SHA1_HASH_SIZE, lte->hash);
 287         if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
 288                 ERROR_WITH_ERRNO("Failed to write lookup table entry");
 289                 return WIMLIB_ERR_WRITE;
 290         }
 291         return 0;
 292 }
 293
 294
 295
 296 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
 297 {
 298         entry->out_refcnt = 0;
 299         return 0;
 300 }
 301
 302 void print_lookup_table_entry(const struct lookup_table_entry *lte)
 303 {
 304         if (!lte) {
 305                 putchar('\n');
 306                 return;
 307         }
 308         printf("Offset            = %"PRIu64" bytes\n",
 309                lte->resource_entry.offset);
 310         printf("Size              = %"PRIu64" bytes\n",
 311                (u64)lte->resource_entry.size);
 312         printf("Original size     = %"PRIu64" bytes\n",
 313                lte->resource_entry.original_size);
 314         printf("Part Number       = %hu\n", lte->part_number);
 315         printf("Reference Count   = %u\n", lte->refcnt);
 316         printf("Hash              = 0x");
 317         print_hash(lte->hash);
 318         putchar('\n');
 319         printf("Flags             = ");
 320         u8 flags = lte->resource_entry.flags;
 321         if (flags & WIM_RESHDR_FLAG_COMPRESSED)
 322                 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
 323         if (flags & WIM_RESHDR_FLAG_FREE)
 324                 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
 325         if (flags & WIM_RESHDR_FLAG_METADATA)
 326                 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
 327         if (flags & WIM_RESHDR_FLAG_SPANNED)
 328                 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
 329         putchar('\n');
 330         switch (lte->resource_location) {
 331         case RESOURCE_IN_WIM:
 332                 if (lte->wim->filename) {
 333                         printf("WIM file          = `%s'\n",
 334                                lte->wim->filename);
 335                 }
 336                 break;
 337         case RESOURCE_IN_FILE_ON_DISK:
 338                 printf("File on Disk      = `%s'\n", lte->file_on_disk);
 339                 break;
 340         case RESOURCE_IN_STAGING_FILE:
 341                 printf("Staging File      = `%s'\n", lte->staging_file_name);
 342                 break;
 343         }
 344         putchar('\n');
 345 }
 346
 347 static int do_print_lookup_table_entry(struct lookup_table_entry *lte,
 348                                        void *ignore)
 349 {
 350         print_lookup_table_entry(lte);
 351         return 0;
 352 }
 353
 354 /*
 355  * Prints the lookup table of a WIM file.
 356  */
 357 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
 358 {
 359         for_lookup_table_entry(w->lookup_table,
 360                                do_print_lookup_table_entry,
 361                                NULL);
 362 }
 363
 364 /*
 365  * Looks up an entry in the lookup table.
 366  */
 367 struct lookup_table_entry *
 368 __lookup_resource(const struct lookup_table *table, const u8 hash[])
 369 {
 370         size_t i;
 371         struct lookup_table_entry *lte;
 372         struct hlist_node *pos;
 373
 374         i = *(size_t*)hash % table->capacity;
 375         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 376                 if (hashes_equal(hash, lte->hash))
 377                         return lte;
 378         return NULL;
 379 }
 380
 381 /*
 382  * Finds the dentry, lookup table entry, and stream index for a WIM file stream,
 383  * given a path name.
 384  *
 385  * This is only for pre-resolved dentries.
 386  */
 387 int lookup_resource(WIMStruct *w, const char *path,
 388                     int lookup_flags,
 389                     struct dentry **dentry_ret,
 390                     struct lookup_table_entry **lte_ret,
 391                     unsigned *stream_idx_ret)
 392 {
 393         struct dentry *dentry;
 394         struct lookup_table_entry *lte;
 395         unsigned stream_idx;
 396         const char *stream_name;
 397         char *p = NULL;
 398
 399         if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
 400                 stream_name = path_stream_name(path);
 401                 if (stream_name) {
 402                         p = (char*)stream_name - 1;
 403                         *p = '\0';
 404                 }
 405         }
 406
 407         dentry = get_dentry(w, path);
 408         if (p)
 409                 *p = ':';
 410         if (!dentry)
 411                 return -ENOENT;
 412
 413         wimlib_assert(dentry->resolved);
 414
 415         lte = dentry->lte;
 416         if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
 417               && dentry_is_directory(dentry))
 418                 return -EISDIR;
 419         stream_idx = 0;
 420         if (stream_name) {
 421                 size_t stream_name_len = strlen(stream_name);
 422                 for (u16 i = 0; i < dentry->num_ads; i++) {
 423                         if (ads_entry_has_name(&dentry->ads_entries[i],
 424                                                stream_name,
 425                                                stream_name_len))
 426                         {
 427                                 stream_idx = i + 1;
 428                                 lte = dentry->ads_entries[i].lte;
 429                                 goto out;
 430                         }
 431                 }
 432                 return -ENOENT;
 433         }
 434 out:
 435         if (dentry_ret)
 436                 *dentry_ret = dentry;
 437         if (lte_ret)
 438                 *lte_ret = lte;
 439         if (stream_idx_ret)
 440                 *stream_idx_ret = stream_idx;
 441         return 0;
 442 }
 443
 444 /* Resolve a dentry's lookup table entries
 445  *
 446  * This replaces the SHA1 hash fields (which are used to lookup an entry in the
 447  * lookup table) with pointers directly to the lookup table entries.  A circular
 448  * linked list of streams sharing the same lookup table entry is created.
 449  *
 450  * This function always succeeds; unresolved lookup table entries are given a
 451  * NULL pointer.
 452  */
 453 int dentry_resolve_ltes(struct dentry *dentry, void *__table)
 454 {
 455         struct lookup_table *table = __table;
 456         struct lookup_table_entry *lte;
 457
 458         if (dentry->resolved)
 459                 return 0;
 460
 461         /* Resolve the default file stream */
 462         lte = __lookup_resource(table, dentry->hash);
 463         if (lte)
 464                 list_add(&dentry->lte_group_list.list, &lte->lte_group_list);
 465         else
 466                 INIT_LIST_HEAD(&dentry->lte_group_list.list);
 467         dentry->lte = lte;
 468         dentry->lte_group_list.type = STREAM_TYPE_NORMAL;
 469         dentry->resolved = true;
 470
 471         /* Resolve the alternate data streams */
 472         if (dentry->ads_entries_status != ADS_ENTRIES_USER) {
 473                 for (u16 i = 0; i < dentry->num_ads; i++) {
 474                         struct ads_entry *cur_entry = &dentry->ads_entries[i];
 475
 476                         lte = __lookup_resource(table, cur_entry->hash);
 477                         if (lte)
 478                                 list_add(&cur_entry->lte_group_list.list,
 479                                          &lte->lte_group_list);
 480                         else
 481                                 INIT_LIST_HEAD(&cur_entry->lte_group_list.list);
 482                         cur_entry->lte = lte;
 483                         cur_entry->lte_group_list.type = STREAM_TYPE_ADS;
 484                 }
 485         }
 486         return 0;
 487 }
 488
 489 struct lookup_table_entry *
 490 dentry_first_lte(const struct dentry *dentry, const struct lookup_table *table)
 491 {
 492         if (dentry->resolved)
 493                 return dentry_first_lte_resolved(dentry);
 494         else
 495                 return dentry_first_lte_unresolved(dentry, table);
 496 }
 497