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_crc32c.h"
  44 #include "ext4_debug.h"
  45 #include "ext4_block_group.h"
  46 #include "ext4_balloc.h"
  47 #include "ext4_inode.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 uint32_t
 116 ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
 117                           ext4_fsblk_t blocknr,
 118                           struct ext4_xattr_header *header)
 119 {
 120         uint32_t checksum = 0;
 121         uint64_t le64_blocknr = blocknr;
 122         struct ext4_sblock *sb = &inode_ref->fs->sb;
 123
 124         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 125                 uint32_t orig_checksum;
 126
 127                 /* Preparation: temporarily set bg checksum to 0 */
 128                 orig_checksum = header->h_checksum;
 129                 header->h_checksum = 0;
 130                 /* First calculate crc32 checksum against fs uuid */
 131                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 132                                 sizeof(sb->uuid));
 133                 /* Then calculate crc32 checksum block number */
 134                 checksum = ext4_crc32c(checksum, &le64_blocknr,
 135                                      sizeof(le64_blocknr));
 136                 /* Finally calculate crc32 checksum against
 137                  * the entire xattr block */
 138                 checksum = ext4_crc32c(checksum, header,
 139                                    ext4_sb_get_block_size(sb));
 140                 header->h_checksum = orig_checksum;
 141         }
 142         return checksum;
 143 }
 144
 145 static void
 146 ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
 147                               ext4_fsblk_t blocknr,
 148                               struct ext4_xattr_header *header)
 149 {
 150         struct ext4_sblock *sb = &inode_ref->fs->sb;
 151         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 152                 return;
 153
 154         header->h_checksum =
 155                 ext4_xattr_block_checksum(inode_ref, blocknr, header);
 156 }
 157
 158 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 159                                struct ext4_xattr_item *b)
 160 {
 161         int result;
 162         result = a->name_index - b->name_index;
 163         if (result)
 164                 return result;
 165
 166         result = a->name_len - b->name_len;
 167         if (result)
 168                 return result;
 169
 170         return memcmp(a->name, b->name, a->name_len);
 171 }
 172
 173 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 174                      ext4_xattr_item_cmp, static inline)
 175
 176 static struct ext4_xattr_item *
 177 ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 178 {
 179         struct ext4_xattr_item *item;
 180         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 181         if (!item)
 182                 return NULL;
 183
 184         item->name_index = name_index;
 185         item->name = (char *)(item + 1);
 186         item->name_len = name_len;
 187         item->data = NULL;
 188         item->data_size = 0;
 189
 190         memset(&item->node, 0, sizeof(item->node));
 191         memcpy(item->name, name, name_len);
 192
 193         return item;
 194 }
 195
 196 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 197                                       const void *orig_data, size_t data_size)
 198 {
 199         void *data = NULL;
 200         ext4_assert(!item->data);
 201         data = malloc(data_size);
 202         if (!data)
 203                 return ENOMEM;
 204
 205         if (orig_data)
 206                 memcpy(data, orig_data, data_size);
 207
 208         item->data = data;
 209         item->data_size = data_size;
 210         return EOK;
 211 }
 212
 213 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 214 {
 215         ext4_assert(item->data);
 216         free(item->data);
 217         item->data = NULL;
 218         item->data_size = 0;
 219 }
 220
 221 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 222                                        size_t new_data_size)
 223 {
 224         if (new_data_size != item->data_size) {
 225                 void *new_data;
 226                 new_data = realloc(item->data, new_data_size);
 227                 if (!new_data)
 228                         return ENOMEM;
 229
 230                 item->data = new_data;
 231                 item->data_size = new_data_size;
 232         }
 233         return EOK;
 234 }
 235
 236 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 237 {
 238         if (item->data)
 239                 ext4_xattr_item_free_data(item);
 240
 241         free(item);
 242 }
 243
 244 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 245                                    struct ext4_xattr_entry *entry,
 246                                    bool in_inode)
 247 {
 248         char *ret;
 249         if (in_inode) {
 250                 struct ext4_xattr_ibody_header *header;
 251                 struct ext4_xattr_entry *first_entry;
 252                 int16_t inode_size =
 253                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 254                 header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 255                 first_entry = EXT4_XATTR_IFIRST(header);
 256
 257                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 258                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 259                         (char *)xattr_ref->inode_ref->inode > inode_size)
 260                         ret = NULL;
 261
 262                 return ret;
 263
 264         }
 265         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 266         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 267         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 268                         (char *)xattr_ref->block.data > block_size)
 269                 ret = NULL;
 270         return ret;
 271 }
 272
 273 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 274 {
 275         int ret = EOK;
 276         size_t size_rem;
 277         void *data;
 278         struct ext4_xattr_entry *entry = NULL;
 279
 280         ext4_assert(xattr_ref->block.data);
 281         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 282
 283         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 284         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 285              entry = EXT4_XATTR_NEXT(entry),
 286              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 287                 struct ext4_xattr_item *item;
 288                 char *e_name = EXT4_XATTR_NAME(entry);
 289
 290                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 291                 if (!data) {
 292                         ret = EIO;
 293                         goto Finish;
 294                 }
 295
 296                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 297                                              (size_t)entry->e_name_len);
 298                 if (!item) {
 299                         ret = ENOMEM;
 300                         goto Finish;
 301                 }
 302                 if (ext4_xattr_item_alloc_data(
 303                         item, data, to_le32(entry->e_value_size)) != EOK) {
 304                         ext4_xattr_item_free(item);
 305                         ret = ENOMEM;
 306                         goto Finish;
 307                 }
 308                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 309                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 310                                       EXT4_XATTR_LEN(item->name_len);
 311         }
 312
 313 Finish:
 314         return ret;
 315 }
 316
 317 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 318 {
 319         void *data;
 320         size_t size_rem;
 321         int ret = EOK;
 322         struct ext4_xattr_ibody_header *header = NULL;
 323         struct ext4_xattr_entry *entry = NULL;
 324         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 325
 326         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 327         entry = EXT4_XATTR_IFIRST(header);
 328
 329         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 330                    xattr_ref->inode_ref->inode->extra_isize;
 331         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 332              entry = EXT4_XATTR_NEXT(entry),
 333              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 334                 struct ext4_xattr_item *item;
 335                 char *e_name = EXT4_XATTR_NAME(entry);
 336
 337                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 338                 if (!data) {
 339                         ret = EIO;
 340                         goto Finish;
 341                 }
 342
 343                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 344                                              (size_t)entry->e_name_len);
 345                 if (!item) {
 346                         ret = ENOMEM;
 347                         goto Finish;
 348                 }
 349                 if (ext4_xattr_item_alloc_data(
 350                         item, data, to_le32(entry->e_value_size)) != EOK) {
 351                         ext4_xattr_item_free(item);
 352                         ret = ENOMEM;
 353                         goto Finish;
 354                 }
 355                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 356                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 357                                       EXT4_XATTR_LEN(item->name_len);
 358         }
 359
 360 Finish:
 361         return ret;
 362 }
 363
 364 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 365 {
 366         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 367         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 368                             xattr_ref->inode_ref->inode->extra_isize;
 369         return size_rem;
 370 }
 371
 372 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 373 {
 374         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 375 }
 376
 377 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 378 {
 379         int ret = EOK;
 380         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 381         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 382                 ret = ext4_xattr_inode_fetch(xattr_ref);
 383                 if (ret != EOK)
 384                         return ret;
 385         }
 386
 387         if (xattr_ref->block_loaded)
 388                 ret = ext4_xattr_block_fetch(xattr_ref);
 389
 390         xattr_ref->dirty = false;
 391         return ret;
 392 }
 393
 394 static struct ext4_xattr_item *
 395 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 396                        const char *name, size_t name_len)
 397 {
 398         struct ext4_xattr_item tmp = {
 399                 .name_index = name_index,
 400                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 401                 .name_len = name_len,
 402         };
 403
 404         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 405 }
 406
 407 static struct ext4_xattr_item *
 408 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 409                        const char *name, size_t name_len, const void *data,
 410                        size_t data_size)
 411 {
 412         struct ext4_xattr_item *item;
 413         item = ext4_xattr_item_alloc(name_index, name, name_len);
 414         if (!item)
 415                 return NULL;
 416
 417         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 418                 EXT4_XATTR_LEN(item->name_len)
 419                         >
 420             ext4_xattr_inode_space(xattr_ref) -
 421                 sizeof(struct ext4_xattr_ibody_header))
 422                 &&
 423             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 424                 EXT4_XATTR_LEN(item->name_len) >
 425             ext4_xattr_block_space(xattr_ref) -
 426                 sizeof(struct ext4_xattr_header))) {
 427                 ext4_xattr_item_free(item);
 428
 429                 return NULL;
 430         }
 431         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 432                 ext4_xattr_item_free(item);
 433                 return NULL;
 434         }
 435         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 436         xattr_ref->ea_size +=
 437             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 438         xattr_ref->dirty = true;
 439         return item;
 440 }
 441
 442 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 443                                   uint8_t name_index, const char *name,
 444                                   size_t name_len)
 445 {
 446         int ret = ENOENT;
 447         struct ext4_xattr_item *item =
 448             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 449         if (item) {
 450                 if (item == xattr_ref->iter_from)
 451                         xattr_ref->iter_from =
 452                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 453
 454                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 455                                       EXT4_XATTR_LEN(item->name_len);
 456
 457                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 458                 ext4_xattr_item_free(item);
 459                 xattr_ref->dirty = true;
 460                 ret = EOK;
 461         }
 462         return ret;
 463 }
 464
 465 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 466                                   struct ext4_xattr_item *item,
 467                                   size_t new_data_size)
 468 {
 469         int ret = EOK;
 470         size_t old_data_size = item->data_size;
 471         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 472                 EXT4_XATTR_SIZE(new_data_size)
 473                         >
 474             ext4_xattr_inode_space(xattr_ref) -
 475                 sizeof(struct ext4_xattr_ibody_header))
 476                 &&
 477             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 478                 EXT4_XATTR_SIZE(new_data_size)
 479                         >
 480             ext4_xattr_block_space(xattr_ref) -
 481                 sizeof(struct ext4_xattr_header))) {
 482
 483                 return ENOSPC;
 484         }
 485         ret = ext4_xattr_item_resize_data(item, new_data_size);
 486         if (ret != EOK) {
 487                 return ret;
 488         }
 489         xattr_ref->ea_size =
 490             xattr_ref->ea_size -
 491             EXT4_XATTR_SIZE(old_data_size) +
 492             EXT4_XATTR_SIZE(new_data_size);
 493         xattr_ref->dirty = true;
 494         return ret;
 495 }
 496
 497 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 498 {
 499         struct ext4_xattr_item *item, *save_item;
 500         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 501         {
 502                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 503                 ext4_xattr_item_free(item);
 504         }
 505         xattr_ref->ea_size = 0;
 506 }
 507
 508 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 509 {
 510         int ret = EOK;
 511
 512         ext4_fsblk_t xattr_block = 0;
 513         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 514                                               &xattr_ref->fs->sb);
 515         if (!xattr_block) {
 516                 ext4_fsblk_t goal =
 517                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 518
 519                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 520                                               goal,
 521                                               &xattr_block);
 522                 if (ret != EOK)
 523                         goto Finish;
 524
 525                 ret = ext4_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 526                                      xattr_block);
 527                 if (ret != EOK) {
 528                         ext4_balloc_free_block(xattr_ref->inode_ref,
 529                                                xattr_block);
 530                         goto Finish;
 531                 }
 532
 533                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 534                                         &xattr_ref->fs->sb, xattr_block);
 535                 xattr_ref->inode_ref->dirty = true;
 536                 xattr_ref->block_loaded = true;
 537         }
 538
 539 Finish:
 540         return ret;
 541 }
 542
 543 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 544 {
 545         ext4_fsblk_t xattr_block;
 546         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 547                                               &xattr_ref->fs->sb);
 548         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 549                                 0);
 550         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 551         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 552         xattr_ref->inode_ref->dirty = true;
 553         xattr_ref->block_loaded = false;
 554 }
 555
 556 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 557 {
 558         struct ext4_xattr_header *block_header = NULL;
 559         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 560
 561         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 562         block_header->h_magic = EXT4_XATTR_MAGIC;
 563         block_header->h_refcount = to_le32(1);
 564         block_header->h_blocks = to_le32(1);
 565 }
 566
 567 static void
 568 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 569                            struct ext4_xattr_ibody_header *ibody_header,
 570                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 571 {
 572         entry->e_name_len = to_le32(item->name_len);
 573         entry->e_name_index = item->name_index;
 574         entry->e_value_offs =
 575             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 576         entry->e_value_block = 0;
 577         entry->e_value_size = item->data_size;
 578 }
 579
 580 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 581                                        struct ext4_xattr_header *block_header,
 582                                        struct ext4_xattr_entry *block_entry,
 583                                        void *block_data_ptr)
 584 {
 585         block_entry->e_name_len = to_le32(item->name_len);
 586         block_entry->e_name_index = item->name_index;
 587         block_entry->e_value_offs =
 588             (char *)block_data_ptr - (char *)block_header;
 589         block_entry->e_value_block = 0;
 590         block_entry->e_value_size = item->data_size;
 591 }
 592
 593 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 594 {
 595         int ret = EOK;
 596         bool block_modified = false;
 597         void *ibody_data = NULL;
 598         void *block_data = NULL;
 599         struct ext4_xattr_item *item, *save_item;
 600         size_t inode_size_rem, block_size_rem;
 601         struct ext4_xattr_ibody_header *ibody_header = NULL;
 602         struct ext4_xattr_header *block_header = NULL;
 603         struct ext4_xattr_entry *entry = NULL;
 604         struct ext4_xattr_entry *block_entry = NULL;
 605
 606         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 607         block_size_rem = ext4_xattr_block_space(xattr_ref);
 608         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 609                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 610                 entry = EXT4_XATTR_IFIRST(ibody_header);
 611         }
 612
 613         if (!xattr_ref->dirty)
 614                 goto Finish;
 615         /* If there are enough spaces in the ibody EA table.*/
 616         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 617                 memset(ibody_header, 0, inode_size_rem);
 618                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 619                 ibody_data = (char *)ibody_header + inode_size_rem;
 620                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 621
 622                 xattr_ref->inode_ref->dirty = true;
 623         }
 624         /* If we need an extra block to hold the EA entries*/
 625         if (xattr_ref->ea_size > inode_size_rem) {
 626                 if (!xattr_ref->block_loaded) {
 627                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 628                         if (ret != EOK)
 629                                 goto Finish;
 630                 }
 631                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 632                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 633                 ext4_xattr_set_block_header(xattr_ref);
 634                 block_data = (char *)block_header + block_size_rem;
 635                 block_size_rem -= sizeof(struct ext4_xattr_header);
 636
 637                 xattr_ref->block.dirty = true;
 638         } else {
 639                 /* We don't need an extra block.*/
 640                 if (xattr_ref->block_loaded) {
 641                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 642                         block_header->h_refcount =
 643                             to_le32(to_le32(block_header->h_refcount) - 1);
 644                         if (!block_header->h_refcount) {
 645                                 ext4_xattr_try_free_block(xattr_ref);
 646                                 block_header = NULL;
 647                         } else {
 648                                 block_entry =
 649                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 650                                 block_data =
 651                                     (char *)block_header + block_size_rem;
 652                                 block_size_rem -=
 653                                     sizeof(struct ext4_xattr_header);
 654                                 ext4_inode_set_file_acl(
 655                                     xattr_ref->inode_ref->inode,
 656                                     &xattr_ref->fs->sb, 0);
 657
 658                                 xattr_ref->inode_ref->dirty = true;
 659                                 xattr_ref->block.dirty = true;
 660                         }
 661                 }
 662         }
 663         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 664         {
 665                 if (EXT4_XATTR_SIZE(item->data_size) +
 666                         EXT4_XATTR_LEN(item->name_len) <=
 667                     inode_size_rem) {
 668                         ibody_data = (char *)ibody_data -
 669                                      EXT4_XATTR_SIZE(item->data_size);
 670                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 671                                                    ibody_data);
 672                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 673                                item->name_len);
 674                         memcpy(ibody_data, item->data, item->data_size);
 675                         entry = EXT4_XATTR_NEXT(entry);
 676                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 677                                           EXT4_XATTR_LEN(item->name_len);
 678
 679                         xattr_ref->inode_ref->dirty = true;
 680                         continue;
 681                 }
 682                 if (EXT4_XATTR_SIZE(item->data_size) +
 683                         EXT4_XATTR_LEN(item->name_len) >
 684                     block_size_rem) {
 685                         ret = ENOSPC;
 686                         goto Finish;
 687                 }
 688                 block_data =
 689                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 690                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 691                                            block_data);
 692                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 693                        item->name_len);
 694                 memcpy(block_data, item->data, item->data_size);
 695                 block_entry = EXT4_XATTR_NEXT(block_entry);
 696                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 697                                   EXT4_XATTR_LEN(item->name_len);
 698
 699                 block_modified = true;
 700         }
 701         xattr_ref->dirty = false;
 702         if (block_modified) {
 703                 ext4_xattr_rehash(block_header,
 704                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 705                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 706                                               xattr_ref->block.lb_id,
 707                                               block_header);
 708                 xattr_ref->block.dirty = true;
 709         }
 710
 711 Finish:
 712         return ret;
 713 }
 714
 715 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 716                            int (*iter)(struct ext4_xattr_ref *ref,
 717                                      struct ext4_xattr_item *item))
 718 {
 719         struct ext4_xattr_item *item;
 720         if (!ref->iter_from)
 721                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 722
 723         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 724         {
 725                 int ret = EXT4_XATTR_ITERATE_CONT;
 726                 if (iter)
 727                         iter(ref, item);
 728
 729                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 730                         if (ret == EXT4_XATTR_ITERATE_STOP)
 731                                 ref->iter_from = NULL;
 732
 733                         break;
 734                 }
 735         }
 736 }
 737
 738 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 739 {
 740         ref->iter_from = NULL;
 741 }
 742
 743 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 744                       const char *name, size_t name_len, const void *data,
 745                       size_t data_size, bool replace)
 746 {
 747         int ret = EOK;
 748         struct ext4_xattr_item *item =
 749             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 750         if (replace) {
 751                 if (!item) {
 752                         ret = ENODATA;
 753                         goto Finish;
 754                 }
 755                 if (item->data_size != data_size)
 756                         ret = ext4_xattr_resize_item(ref, item, data_size);
 757
 758                 if (ret != EOK) {
 759                         goto Finish;
 760                 }
 761                 memcpy(item->data, data, data_size);
 762         } else {
 763                 if (item) {
 764                         ret = EEXIST;
 765                         goto Finish;
 766                 }
 767                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 768                                               data, data_size);
 769                 if (!item)
 770                         ret = ENOMEM;
 771         }
 772 Finish:
 773         return ret;
 774 }
 775
 776 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 777                          const char *name, size_t name_len)
 778 {
 779         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 780 }
 781
 782 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 783                       const char *name, size_t name_len, void *buf, size_t buf_size,
 784                       size_t *data_size)
 785 {
 786         int ret = EOK;
 787         size_t item_size = 0;
 788         struct ext4_xattr_item *item =
 789             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 790
 791         if (!item) {
 792                 ret = ENODATA;
 793                 goto Finish;
 794         }
 795         item_size = item->data_size;
 796         if (buf_size > item_size)
 797                 buf_size = item_size;
 798
 799         if (buf)
 800                 memcpy(buf, item->data, buf_size);
 801
 802 Finish:
 803         if (data_size)
 804                 *data_size = item_size;
 805
 806         return ret;
 807 }
 808
 809 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 810                           struct ext4_xattr_ref *ref)
 811 {
 812         int rc;
 813         ext4_fsblk_t xattr_block;
 814         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 815         RB_INIT(&ref->root);
 816         ref->ea_size = 0;
 817         ref->iter_from = NULL;
 818         if (xattr_block) {
 819                 rc = ext4_block_get(fs->bdev, &ref->block, xattr_block);
 820                 if (rc != EOK)
 821                         return EIO;
 822
 823                 ref->block_loaded = true;
 824         } else
 825                 ref->block_loaded = false;
 826
 827         ref->inode_ref = inode_ref;
 828         ref->fs = fs;
 829
 830         rc = ext4_xattr_fetch(ref);
 831         if (rc != EOK) {
 832                 ext4_xattr_purge_items(ref);
 833                 if (xattr_block)
 834                         ext4_block_set(fs->bdev, &inode_ref->block);
 835
 836                 ref->block_loaded = false;
 837                 return rc;
 838         }
 839         return EOK;
 840 }
 841
 842 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 843 {
 844         ext4_xattr_write_to_disk(ref);
 845         if (ref->block_loaded) {
 846                 ext4_block_set(ref->fs->bdev, &ref->block);
 847                 ref->block_loaded = false;
 848         }
 849         ext4_xattr_purge_items(ref);
 850         ref->inode_ref = NULL;
 851         ref->fs = NULL;
 852 }
 853
 854 struct xattr_prefix {
 855         const char *prefix;
 856         uint8_t name_index;
 857 };
 858
 859 static const struct xattr_prefix prefix_tbl[] = {
 860     {"user.", EXT4_XATTR_INDEX_USER},
 861     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 862     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 863     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 864     {NULL, 0},
 865 };
 866
 867 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 868                               uint8_t *name_index, size_t *name_len)
 869 {
 870         int i;
 871         ext4_assert(name_index);
 872         if (!full_name_len) {
 873                 if (name_len)
 874                         *name_len = 0;
 875
 876                 return NULL;
 877         }
 878
 879         for (i = 0; prefix_tbl[i].prefix; i++) {
 880                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 881                 if (full_name_len >= prefix_len &&
 882                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 883                         *name_index = prefix_tbl[i].name_index;
 884                         if (name_len)
 885                                 *name_len = full_name_len - prefix_len;
 886
 887                         return full_name + prefix_len;
 888                 }
 889         }
 890         if (name_len)
 891                 *name_len = 0;
 892
 893         return NULL;
 894 }
 895
 896 const char *ext4_get_xattr_name_prefix(uint8_t name_index, size_t *ret_prefix_len)
 897 {
 898         int i;
 899
 900         for (i = 0; prefix_tbl[i].prefix; i++) {
 901                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 902                 if (prefix_tbl[i].name_index == name_index) {
 903                         if (ret_prefix_len)
 904                                 *ret_prefix_len = prefix_len;
 905
 906                         return prefix_tbl[i].prefix;
 907                 }
 908         }
 909         if (ret_prefix_len)
 910                 *ret_prefix_len = 0;
 911
 912         return NULL;
 913 }
 914
 915 /**
 916  * @}
 917  */