lwext4/ext4_xattr.c

   1 /*
   2  * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com)
   3  * Copyright (c) 2015 Kaho Ng (ngkaho1234@gmail.com)
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup lwext4
  30  * @{
  31  */
  32 /**
  33  * @file  ext4_xattr.c
  34  * @brief Extended Attribute manipulation.
  35  */
  36
  37 #include "ext4_config.h"
  38 #include "ext4_types.h"
  39 #include "ext4_fs.h"
  40 #include "ext4_errno.h"
  41 #include "ext4_blockdev.h"
  42 #include "ext4_super.h"
  43 #include "ext4_debug.h"
  44 #include "ext4_block_group.h"
  45 #include "ext4_balloc.h"
  46 #include "ext4_inode.h"
  47 #include "ext4_extent.h"
  48
  49 #include <string.h>
  50 #include <stdlib.h>
  51
  52 /**
  53  * @file  ext4_xattr.c
  54  * @brief Extended Attribute Manipulation
  55  */
  56
  57 #define NAME_HASH_SHIFT 5
  58 #define VALUE_HASH_SHIFT 16
  59
  60 static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
  61                                            struct ext4_xattr_entry *entry)
  62 {
  63         uint32_t hash = 0;
  64         char *name = EXT4_XATTR_NAME(entry);
  65         int n;
  66
  67         for (n = 0; n < entry->e_name_len; n++) {
  68                 hash = (hash << NAME_HASH_SHIFT) ^
  69                        (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
  70         }
  71
  72         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
  73                 uint32_t *value =
  74                     (uint32_t *)((char *)header + to_le16(entry->e_value_offs));
  75                 for (n = (to_le32(entry->e_value_size) + EXT4_XATTR_ROUND) >>
  76                          EXT4_XATTR_PAD_BITS;
  77                      n; n--) {
  78                         hash = (hash << VALUE_HASH_SHIFT) ^
  79                                (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
  80                                to_le32(*value++);
  81                 }
  82         }
  83         entry->e_hash = to_le32(hash);
  84 }
  85
  86 #define BLOCK_HASH_SHIFT 16
  87
  88 /*
  89  * ext4_xattr_rehash()
  90  *
  91  * Re-compute the extended attribute hash value after an entry has changed.
  92  */
  93 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
  94                               struct ext4_xattr_entry *entry)
  95 {
  96         struct ext4_xattr_entry *here;
  97         uint32_t hash = 0;
  98
  99         ext4_xattr_compute_hash(header, entry);
 100         here = EXT4_XATTR_ENTRY(header + 1);
 101         while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
 102                 if (!here->e_hash) {
 103                         /* Block is not shared if an entry's hash value == 0 */
 104                         hash = 0;
 105                         break;
 106                 }
 107                 hash = (hash << BLOCK_HASH_SHIFT) ^
 108                        (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
 109                        to_le32(here->e_hash);
 110                 here = EXT4_XATTR_NEXT(here);
 111         }
 112         header->h_hash = to_le32(hash);
 113 }
 114
 115 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 116                                struct ext4_xattr_item *b)
 117 {
 118         int result;
 119         result = a->name_index - b->name_index;
 120         if (result)
 121                 return result;
 122
 123         result = a->name_len - b->name_len;
 124         if (result)
 125                 return result;
 126
 127         return memcmp(a->name, b->name, a->name_len);
 128 }
 129
 130 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 131                      ext4_xattr_item_cmp, static inline)
 132
 133 static struct ext4_xattr_item *
 134 ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 135 {
 136         struct ext4_xattr_item *item;
 137         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 138         if (!item)
 139                 return NULL;
 140
 141         item->name_index = name_index;
 142         item->name = (char *)(item + 1);
 143         item->name_len = name_len;
 144         item->data = NULL;
 145         item->data_size = 0;
 146
 147         memset(&item->node, 0, sizeof(item->node));
 148         memcpy(item->name, name, name_len);
 149
 150         return item;
 151 }
 152
 153 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 154                                       const void *orig_data, size_t data_size)
 155 {
 156         void *data = NULL;
 157         ext4_assert(!item->data);
 158         data = malloc(data_size);
 159         if (!data)
 160                 return ENOMEM;
 161
 162         if (orig_data)
 163                 memcpy(data, orig_data, data_size);
 164
 165         item->data = data;
 166         item->data_size = data_size;
 167         return EOK;
 168 }
 169
 170 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 171 {
 172         ext4_assert(item->data);
 173         free(item->data);
 174         item->data = NULL;
 175         item->data_size = 0;
 176 }
 177
 178 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 179                                        size_t new_data_size)
 180 {
 181         if (new_data_size != item->data_size) {
 182                 void *new_data;
 183                 new_data = realloc(item->data, new_data_size);
 184                 if (!new_data)
 185                         return ENOMEM;
 186
 187                 item->data = new_data;
 188                 item->data_size = new_data_size;
 189         }
 190         return EOK;
 191 }
 192
 193 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 194 {
 195         if (item->data)
 196                 ext4_xattr_item_free_data(item);
 197
 198         free(item);
 199 }
 200
 201 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 202                                    struct ext4_xattr_entry *entry,
 203                                    bool in_inode)
 204 {
 205         char *ret;
 206         if (in_inode) {
 207                 struct ext4_xattr_ibody_header *header;
 208                 struct ext4_xattr_entry *first_entry;
 209                 int16_t inode_size =
 210                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 211                 header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 212                 first_entry = EXT4_XATTR_IFIRST(header);
 213
 214                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 215                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 216                         (char *)xattr_ref->inode_ref->inode > inode_size)
 217                         ret = NULL;
 218
 219                 return ret;
 220
 221         }
 222         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 223         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 224         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 225                         (char *)xattr_ref->block.data > block_size)
 226                 ret = NULL;
 227         return ret;
 228 }
 229
 230 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 231 {
 232         int ret = EOK;
 233         size_t size_rem;
 234         void *data;
 235         struct ext4_xattr_entry *entry = NULL;
 236
 237         ext4_assert(xattr_ref->block.data);
 238         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 239
 240         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 241         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 242              entry = EXT4_XATTR_NEXT(entry),
 243              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 244                 struct ext4_xattr_item *item;
 245                 char *e_name = EXT4_XATTR_NAME(entry);
 246
 247                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 248                 if (!data) {
 249                         ret = EIO;
 250                         goto Finish;
 251                 }
 252
 253                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 254                                              (size_t)entry->e_name_len);
 255                 if (!item) {
 256                         ret = ENOMEM;
 257                         goto Finish;
 258                 }
 259                 if (ext4_xattr_item_alloc_data(
 260                         item, data, to_le32(entry->e_value_size)) != EOK) {
 261                         ext4_xattr_item_free(item);
 262                         ret = ENOMEM;
 263                         goto Finish;
 264                 }
 265                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 266                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 267                                       EXT4_XATTR_LEN(item->name_len);
 268         }
 269
 270 Finish:
 271         return ret;
 272 }
 273
 274 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 275 {
 276         void *data;
 277         size_t size_rem;
 278         int ret = EOK;
 279         struct ext4_xattr_ibody_header *header = NULL;
 280         struct ext4_xattr_entry *entry = NULL;
 281         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 282
 283         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 284         entry = EXT4_XATTR_IFIRST(header);
 285
 286         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 287                    xattr_ref->inode_ref->inode->extra_isize;
 288         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 289              entry = EXT4_XATTR_NEXT(entry),
 290              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 291                 struct ext4_xattr_item *item;
 292                 char *e_name = EXT4_XATTR_NAME(entry);
 293
 294                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 295                 if (!data) {
 296                         ret = EIO;
 297                         goto Finish;
 298                 }
 299
 300                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 301                                              (size_t)entry->e_name_len);
 302                 if (!item) {
 303                         ret = ENOMEM;
 304                         goto Finish;
 305                 }
 306                 if (ext4_xattr_item_alloc_data(
 307                         item, data, to_le32(entry->e_value_size)) != EOK) {
 308                         ext4_xattr_item_free(item);
 309                         ret = ENOMEM;
 310                         goto Finish;
 311                 }
 312                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 313                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 314                                       EXT4_XATTR_LEN(item->name_len);
 315         }
 316
 317 Finish:
 318         return ret;
 319 }
 320
 321 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 322 {
 323         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 324         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 325                             xattr_ref->inode_ref->inode->extra_isize;
 326         return size_rem;
 327 }
 328
 329 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 330 {
 331         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 332 }
 333
 334 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 335 {
 336         int ret = EOK;
 337         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 338         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 339                 ret = ext4_xattr_inode_fetch(xattr_ref);
 340                 if (ret != EOK)
 341                         return ret;
 342         }
 343
 344         if (xattr_ref->block_loaded)
 345                 ret = ext4_xattr_block_fetch(xattr_ref);
 346
 347         xattr_ref->dirty = false;
 348         return ret;
 349 }
 350
 351 static struct ext4_xattr_item *
 352 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 353                        const char *name, size_t name_len)
 354 {
 355         struct ext4_xattr_item tmp = {
 356                 .name_index = name_index,
 357                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 358                 .name_len = name_len,
 359         };
 360
 361         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 362 }
 363
 364 static struct ext4_xattr_item *
 365 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 366                        const char *name, size_t name_len, const void *data,
 367                        size_t data_size)
 368 {
 369         struct ext4_xattr_item *item;
 370         item = ext4_xattr_item_alloc(name_index, name, name_len);
 371         if (!item)
 372                 return NULL;
 373
 374         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 375                 EXT4_XATTR_LEN(item->name_len)
 376                         >
 377             ext4_xattr_inode_space(xattr_ref) -
 378                 sizeof(struct ext4_xattr_ibody_header))
 379                 &&
 380             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 381                 EXT4_XATTR_LEN(item->name_len) >
 382             ext4_xattr_block_space(xattr_ref) -
 383                 sizeof(struct ext4_xattr_header))) {
 384                 ext4_xattr_item_free(item);
 385
 386                 return NULL;
 387         }
 388         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 389                 ext4_xattr_item_free(item);
 390                 return NULL;
 391         }
 392         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 393         xattr_ref->ea_size +=
 394             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 395         xattr_ref->dirty = true;
 396         return item;
 397 }
 398
 399 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 400                                   uint8_t name_index, const char *name,
 401                                   size_t name_len)
 402 {
 403         int ret = ENOENT;
 404         struct ext4_xattr_item *item =
 405             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 406         if (item) {
 407                 if (item == xattr_ref->iter_from)
 408                         xattr_ref->iter_from =
 409                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 410
 411                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 412                                       EXT4_XATTR_LEN(item->name_len);
 413
 414                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 415                 ext4_xattr_item_free(item);
 416                 xattr_ref->dirty = true;
 417                 ret = EOK;
 418         }
 419         return ret;
 420 }
 421
 422 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 423                                   struct ext4_xattr_item *item,
 424                                   size_t new_data_size)
 425 {
 426         int ret = EOK;
 427         size_t old_data_size = item->data_size;
 428         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 429                 EXT4_XATTR_SIZE(new_data_size)
 430                         >
 431             ext4_xattr_inode_space(xattr_ref) -
 432                 sizeof(struct ext4_xattr_ibody_header))
 433                 &&
 434             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 435                 EXT4_XATTR_SIZE(new_data_size)
 436                         >
 437             ext4_xattr_block_space(xattr_ref) -
 438                 sizeof(struct ext4_xattr_header))) {
 439
 440                 return ENOSPC;
 441         }
 442         ret = ext4_xattr_item_resize_data(item, new_data_size);
 443         if (ret != EOK) {
 444                 return ret;
 445         }
 446         xattr_ref->ea_size =
 447             xattr_ref->ea_size -
 448             EXT4_XATTR_SIZE(old_data_size) +
 449             EXT4_XATTR_SIZE(new_data_size);
 450         xattr_ref->dirty = true;
 451         return ret;
 452 }
 453
 454 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 455 {
 456         struct ext4_xattr_item *item, *save_item;
 457         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 458         {
 459                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 460                 ext4_xattr_item_free(item);
 461         }
 462         xattr_ref->ea_size = 0;
 463 }
 464
 465 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 466 {
 467         int ret = EOK;
 468
 469         uint64_t xattr_block = 0;
 470         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 471                                               &xattr_ref->fs->sb);
 472         if (!xattr_block) {
 473                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 474                                               (uint32_t *)&xattr_block);
 475                 if (ret != EOK)
 476                         goto Finish;
 477
 478                 ret = ext4_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 479                                      xattr_block);
 480                 if (ret != EOK) {
 481                         ext4_balloc_free_block(xattr_ref->inode_ref,
 482                                                xattr_block);
 483                         goto Finish;
 484                 }
 485
 486                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 487                                         &xattr_ref->fs->sb, xattr_block);
 488                 xattr_ref->inode_ref->dirty = true;
 489                 xattr_ref->block_loaded = true;
 490         }
 491
 492 Finish:
 493         return ret;
 494 }
 495
 496 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 497 {
 498         uint64_t xattr_block;
 499         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 500                                               &xattr_ref->fs->sb);
 501         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 502                                 0);
 503         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 504         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 505         xattr_ref->inode_ref->dirty = true;
 506         xattr_ref->block_loaded = false;
 507 }
 508
 509 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 510 {
 511         struct ext4_xattr_header *block_header = NULL;
 512         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 513
 514         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 515         block_header->h_magic = EXT4_XATTR_MAGIC;
 516         block_header->h_refcount = to_le32(1);
 517         block_header->h_blocks = to_le32(1);
 518 }
 519
 520 static void
 521 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 522                            struct ext4_xattr_ibody_header *ibody_header,
 523                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 524 {
 525         entry->e_name_len = to_le32(item->name_len);
 526         entry->e_name_index = item->name_index;
 527         entry->e_value_offs =
 528             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 529         entry->e_value_block = 0;
 530         entry->e_value_size = item->data_size;
 531 }
 532
 533 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 534                                        struct ext4_xattr_header *block_header,
 535                                        struct ext4_xattr_entry *block_entry,
 536                                        void *block_data_ptr)
 537 {
 538         block_entry->e_name_len = to_le32(item->name_len);
 539         block_entry->e_name_index = item->name_index;
 540         block_entry->e_value_offs =
 541             (char *)block_data_ptr - (char *)block_header;
 542         block_entry->e_value_block = 0;
 543         block_entry->e_value_size = item->data_size;
 544 }
 545
 546 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 547 {
 548         int ret = EOK;
 549         bool block_modified = false;
 550         void *ibody_data = NULL;
 551         void *block_data = NULL;
 552         struct ext4_xattr_item *item, *save_item;
 553         size_t inode_size_rem, block_size_rem;
 554         struct ext4_xattr_ibody_header *ibody_header = NULL;
 555         struct ext4_xattr_header *block_header = NULL;
 556         struct ext4_xattr_entry *entry = NULL;
 557         struct ext4_xattr_entry *block_entry = NULL;
 558
 559         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 560         block_size_rem = ext4_xattr_block_space(xattr_ref);
 561         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 562                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 563                 entry = EXT4_XATTR_IFIRST(ibody_header);
 564         }
 565
 566         if (!xattr_ref->dirty)
 567                 goto Finish;
 568         /* If there are enough spaces in the ibody EA table.*/
 569         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 570                 memset(ibody_header, 0, inode_size_rem);
 571                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 572                 ibody_data = (char *)ibody_header + inode_size_rem;
 573                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 574
 575                 xattr_ref->inode_ref->dirty = true;
 576         }
 577         /* If we need an extra block to hold the EA entries*/
 578         if (xattr_ref->ea_size > inode_size_rem) {
 579                 if (!xattr_ref->block_loaded) {
 580                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 581                         if (ret != EOK)
 582                                 goto Finish;
 583                 }
 584                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 585                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 586                 ext4_xattr_set_block_header(xattr_ref);
 587                 block_data = (char *)block_header + block_size_rem;
 588                 block_size_rem -= sizeof(struct ext4_xattr_header);
 589
 590                 xattr_ref->block.dirty = true;
 591         } else {
 592                 /* We don't need an extra block.*/
 593                 if (xattr_ref->block_loaded) {
 594                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 595                         block_header->h_refcount =
 596                             to_le32(to_le32(block_header->h_refcount) - 1);
 597                         if (!block_header->h_refcount) {
 598                                 ext4_xattr_try_free_block(xattr_ref);
 599                                 block_header = NULL;
 600                         } else {
 601                                 block_entry =
 602                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 603                                 block_data =
 604                                     (char *)block_header + block_size_rem;
 605                                 block_size_rem -=
 606                                     sizeof(struct ext4_xattr_header);
 607                                 ext4_inode_set_file_acl(
 608                                     xattr_ref->inode_ref->inode,
 609                                     &xattr_ref->fs->sb, 0);
 610
 611                                 xattr_ref->inode_ref->dirty = true;
 612                                 xattr_ref->block.dirty = true;
 613                         }
 614                 }
 615         }
 616         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 617         {
 618                 if (EXT4_XATTR_SIZE(item->data_size) +
 619                         EXT4_XATTR_LEN(item->name_len) <=
 620                     inode_size_rem) {
 621                         ibody_data = (char *)ibody_data -
 622                                      EXT4_XATTR_SIZE(item->data_size);
 623                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 624                                                    ibody_data);
 625                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 626                                item->name_len);
 627                         memcpy(ibody_data, item->data, item->data_size);
 628                         entry = EXT4_XATTR_NEXT(entry);
 629                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 630                                           EXT4_XATTR_LEN(item->name_len);
 631
 632                         xattr_ref->inode_ref->dirty = true;
 633                         continue;
 634                 }
 635                 if (EXT4_XATTR_SIZE(item->data_size) +
 636                         EXT4_XATTR_LEN(item->name_len) >
 637                     block_size_rem) {
 638                         ret = ENOSPC;
 639                         goto Finish;
 640                 }
 641                 block_data =
 642                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 643                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 644                                            block_data);
 645                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 646                        item->name_len);
 647                 memcpy(block_data, item->data, item->data_size);
 648                 block_entry = EXT4_XATTR_NEXT(block_entry);
 649                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 650                                   EXT4_XATTR_LEN(item->name_len);
 651
 652                 block_modified = true;
 653         }
 654         xattr_ref->dirty = false;
 655         if (block_modified) {
 656                 ext4_xattr_rehash(block_header,
 657                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 658                 xattr_ref->block.dirty = true;
 659         }
 660
 661 Finish:
 662         return ret;
 663 }
 664
 665 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 666                            int (*iter)(struct ext4_xattr_ref *ref,
 667                                      struct ext4_xattr_item *item))
 668 {
 669         struct ext4_xattr_item *item;
 670         if (!ref->iter_from)
 671                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 672
 673         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 674         {
 675                 int ret = EXT4_XATTR_ITERATE_CONT;
 676                 if (iter)
 677                         iter(ref, item);
 678
 679                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 680                         if (ret == EXT4_XATTR_ITERATE_STOP)
 681                                 ref->iter_from = NULL;
 682
 683                         break;
 684                 }
 685         }
 686 }
 687
 688 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 689 {
 690         ref->iter_from = NULL;
 691 }
 692
 693 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 694                       const char *name, size_t name_len, const void *data,
 695                       size_t data_size, bool replace)
 696 {
 697         int ret = EOK;
 698         struct ext4_xattr_item *item =
 699             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 700         if (replace) {
 701                 if (!item) {
 702                         ret = ENODATA;
 703                         goto Finish;
 704                 }
 705                 if (item->data_size != data_size)
 706                         ret = ext4_xattr_resize_item(ref, item, data_size);
 707
 708                 if (ret != EOK) {
 709                         goto Finish;
 710                 }
 711                 memcpy(item->data, data, data_size);
 712         } else {
 713                 if (item) {
 714                         ret = EEXIST;
 715                         goto Finish;
 716                 }
 717                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 718                                               data, data_size);
 719                 if (!item)
 720                         ret = ENOMEM;
 721         }
 722 Finish:
 723         return ret;
 724 }
 725
 726 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 727                          const char *name, size_t name_len)
 728 {
 729         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 730 }
 731
 732 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 733                       const char *name, size_t name_len, void *buf, size_t buf_size,
 734                       size_t *data_size)
 735 {
 736         int ret = EOK;
 737         size_t item_size = 0;
 738         struct ext4_xattr_item *item =
 739             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 740
 741         if (!item) {
 742                 ret = ENODATA;
 743                 goto Finish;
 744         }
 745         item_size = item->data_size;
 746         if (buf_size > item_size)
 747                 buf_size = item_size;
 748
 749         if (buf)
 750                 memcpy(buf, item->data, buf_size);
 751
 752 Finish:
 753         if (data_size)
 754                 *data_size = item_size;
 755
 756         return ret;
 757 }
 758
 759 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 760                           struct ext4_xattr_ref *ref)
 761 {
 762         int rc;
 763         uint64_t xattr_block;
 764         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 765         RB_INIT(&ref->root);
 766         ref->ea_size = 0;
 767         ref->iter_from = NULL;
 768         if (xattr_block) {
 769                 rc = ext4_block_get(fs->bdev, &ref->block, xattr_block);
 770                 if (rc != EOK)
 771                         return EIO;
 772
 773                 ref->block_loaded = true;
 774         } else
 775                 ref->block_loaded = false;
 776
 777         ref->inode_ref = inode_ref;
 778         ref->fs = fs;
 779
 780         rc = ext4_xattr_fetch(ref);
 781         if (rc != EOK) {
 782                 ext4_xattr_purge_items(ref);
 783                 if (xattr_block)
 784                         ext4_block_set(fs->bdev, &inode_ref->block);
 785
 786                 ref->block_loaded = false;
 787                 return rc;
 788         }
 789         return EOK;
 790 }
 791
 792 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 793 {
 794         ext4_xattr_write_to_disk(ref);
 795         if (ref->block_loaded) {
 796                 ext4_block_set(ref->fs->bdev, &ref->block);
 797                 ref->block_loaded = false;
 798         }
 799         ext4_xattr_purge_items(ref);
 800         ref->inode_ref = NULL;
 801         ref->fs = NULL;
 802 }
 803
 804 struct xattr_prefix {
 805         const char *prefix;
 806         uint8_t name_index;
 807 };
 808
 809 static const struct xattr_prefix prefix_tbl[] = {
 810     {"user.", EXT4_XATTR_INDEX_USER},
 811     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 812     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 813     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 814     {NULL, 0},
 815 };
 816
 817 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 818                               uint8_t *name_index, size_t *name_len)
 819 {
 820         int i;
 821         ext4_assert(name_index);
 822         if (!full_name_len) {
 823                 if (name_len)
 824                         *name_len = 0;
 825
 826                 return NULL;
 827         }
 828
 829         for (i = 0; prefix_tbl[i].prefix; i++) {
 830                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 831                 if (full_name_len >= prefix_len &&
 832                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 833                         *name_index = prefix_tbl[i].name_index;
 834                         if (name_len)
 835                                 *name_len = full_name_len - prefix_len;
 836
 837                         return full_name + prefix_len;
 838                 }
 839         }
 840         if (name_len)
 841                 *name_len = 0;
 842
 843         return NULL;
 844 }
 845
 846 const char *ext4_get_xattr_name_prefix(uint8_t name_index, size_t *ret_prefix_len)
 847 {
 848         int i;
 849
 850         for (i = 0; prefix_tbl[i].prefix; i++) {
 851                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 852                 if (prefix_tbl[i].name_index == name_index) {
 853                         if (ret_prefix_len)
 854                                 *ret_prefix_len = prefix_len;
 855
 856                         return prefix_tbl[i].prefix;
 857                 }
 858         }
 859         if (ret_prefix_len)
 860                 *ret_prefix_len = 0;
 861
 862         return NULL;
 863 }
 864
 865 /**
 866  * @}
 867  */