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