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 #if CONFIG_META_CSUM_ENABLE
 116 static uint32_t
 117 ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
 118                           ext4_fsblk_t blocknr,
 119                           struct ext4_xattr_header *header)
 120 {
 121         uint32_t checksum = 0;
 122         uint64_t le64_blocknr = blocknr;
 123         struct ext4_sblock *sb = &inode_ref->fs->sb;
 124
 125         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 126                 uint32_t orig_checksum;
 127
 128                 /* Preparation: temporarily set bg checksum to 0 */
 129                 orig_checksum = header->h_checksum;
 130                 header->h_checksum = 0;
 131                 /* First calculate crc32 checksum against fs uuid */
 132                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 133                                 sizeof(sb->uuid));
 134                 /* Then calculate crc32 checksum block number */
 135                 checksum = ext4_crc32c(checksum, &le64_blocknr,
 136                                      sizeof(le64_blocknr));
 137                 /* Finally calculate crc32 checksum against
 138                  * the entire xattr block */
 139                 checksum = ext4_crc32c(checksum, header,
 140                                    ext4_sb_get_block_size(sb));
 141                 header->h_checksum = orig_checksum;
 142         }
 143         return checksum;
 144 }
 145 #else
 146 #define ext4_xattr_block_checksum(...) 0
 147 #endif
 148
 149 static void
 150 ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
 151                               ext4_fsblk_t blocknr __unused,
 152                               struct ext4_xattr_header *header)
 153 {
 154         struct ext4_sblock *sb = &inode_ref->fs->sb;
 155         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 156                 return;
 157
 158         header->h_checksum =
 159                 ext4_xattr_block_checksum(inode_ref, blocknr, header);
 160 }
 161
 162 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 163                                struct ext4_xattr_item *b)
 164 {
 165         int result;
 166         if (a->in_inode && !b->in_inode)
 167                 return -1;
 168
 169         if (!a->in_inode && b->in_inode)
 170                 return 1;
 171
 172         result = a->name_index - b->name_index;
 173         if (result)
 174                 return result;
 175
 176         result = a->name_len - b->name_len;
 177         if (result)
 178                 return result;
 179
 180         return memcmp(a->name, b->name, a->name_len);
 181 }
 182
 183 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 184                      ext4_xattr_item_cmp, static inline)
 185
 186 static struct ext4_xattr_item *
 187 ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 188 {
 189         struct ext4_xattr_item *item;
 190         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 191         if (!item)
 192                 return NULL;
 193
 194         item->name_index = name_index;
 195         item->name = (char *)(item + 1);
 196         item->name_len = name_len;
 197         item->data = NULL;
 198         item->data_size = 0;
 199
 200         memset(&item->node, 0, sizeof(item->node));
 201         memcpy(item->name, name, name_len);
 202
 203         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 204             name_len == 4 &&
 205             !memcmp(name, "data", 4))
 206                 item->in_inode = true;
 207         else
 208                 item->in_inode = false;
 209
 210         return item;
 211 }
 212
 213 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 214                                       const void *orig_data, size_t data_size)
 215 {
 216         void *data = NULL;
 217         ext4_assert(!item->data);
 218         data = malloc(data_size);
 219         if (!data)
 220                 return ENOMEM;
 221
 222         if (orig_data)
 223                 memcpy(data, orig_data, data_size);
 224
 225         item->data = data;
 226         item->data_size = data_size;
 227         return EOK;
 228 }
 229
 230 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 231 {
 232         ext4_assert(item->data);
 233         free(item->data);
 234         item->data = NULL;
 235         item->data_size = 0;
 236 }
 237
 238 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 239                                        size_t new_data_size)
 240 {
 241         if (new_data_size != item->data_size) {
 242                 void *new_data;
 243                 new_data = realloc(item->data, new_data_size);
 244                 if (!new_data)
 245                         return ENOMEM;
 246
 247                 item->data = new_data;
 248                 item->data_size = new_data_size;
 249         }
 250         return EOK;
 251 }
 252
 253 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 254 {
 255         if (item->data)
 256                 ext4_xattr_item_free_data(item);
 257
 258         free(item);
 259 }
 260
 261 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 262                                    struct ext4_xattr_entry *entry,
 263                                    bool in_inode)
 264 {
 265         char *ret;
 266         if (in_inode) {
 267                 struct ext4_xattr_ibody_header *header;
 268                 struct ext4_xattr_entry *first_entry;
 269                 int16_t inode_size =
 270                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 271                 header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 272                 first_entry = EXT4_XATTR_IFIRST(header);
 273
 274                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 275                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 276                         (char *)xattr_ref->inode_ref->inode > inode_size)
 277                         ret = NULL;
 278
 279                 return ret;
 280
 281         }
 282         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 283         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 284         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 285                         (char *)xattr_ref->block.data > block_size)
 286                 ret = NULL;
 287         return ret;
 288 }
 289
 290 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 291 {
 292         int ret = EOK;
 293         size_t size_rem;
 294         void *data;
 295         struct ext4_xattr_entry *entry = NULL;
 296
 297         ext4_assert(xattr_ref->block.data);
 298         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 299
 300         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 301         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 302              entry = EXT4_XATTR_NEXT(entry),
 303              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 304                 struct ext4_xattr_item *item;
 305                 char *e_name = EXT4_XATTR_NAME(entry);
 306
 307                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 308                 if (!data) {
 309                         ret = EIO;
 310                         goto Finish;
 311                 }
 312
 313                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 314                                              (size_t)entry->e_name_len);
 315                 if (!item) {
 316                         ret = ENOMEM;
 317                         goto Finish;
 318                 }
 319                 if (ext4_xattr_item_alloc_data(
 320                         item, data, to_le32(entry->e_value_size)) != EOK) {
 321                         ext4_xattr_item_free(item);
 322                         ret = ENOMEM;
 323                         goto Finish;
 324                 }
 325                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 326                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 327                                       EXT4_XATTR_LEN(item->name_len);
 328         }
 329
 330 Finish:
 331         return ret;
 332 }
 333
 334 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 335 {
 336         void *data;
 337         size_t size_rem;
 338         int ret = EOK;
 339         struct ext4_xattr_ibody_header *header = NULL;
 340         struct ext4_xattr_entry *entry = NULL;
 341         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 342
 343         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 344         entry = EXT4_XATTR_IFIRST(header);
 345
 346         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 347                    xattr_ref->inode_ref->inode->extra_isize;
 348         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 349              entry = EXT4_XATTR_NEXT(entry),
 350              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 351                 struct ext4_xattr_item *item;
 352                 char *e_name = EXT4_XATTR_NAME(entry);
 353
 354                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 355                 if (!data) {
 356                         ret = EIO;
 357                         goto Finish;
 358                 }
 359
 360                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 361                                              (size_t)entry->e_name_len);
 362                 if (!item) {
 363                         ret = ENOMEM;
 364                         goto Finish;
 365                 }
 366                 if (ext4_xattr_item_alloc_data(
 367                         item, data, to_le32(entry->e_value_size)) != EOK) {
 368                         ext4_xattr_item_free(item);
 369                         ret = ENOMEM;
 370                         goto Finish;
 371                 }
 372                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 373                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 374                                       EXT4_XATTR_LEN(item->name_len);
 375         }
 376
 377 Finish:
 378         return ret;
 379 }
 380
 381 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 382 {
 383         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 384         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 385                             xattr_ref->inode_ref->inode->extra_isize;
 386         return size_rem;
 387 }
 388
 389 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 390 {
 391         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 392 }
 393
 394 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 395 {
 396         int ret = EOK;
 397         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 398         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 399                 ret = ext4_xattr_inode_fetch(xattr_ref);
 400                 if (ret != EOK)
 401                         return ret;
 402         }
 403
 404         if (xattr_ref->block_loaded)
 405                 ret = ext4_xattr_block_fetch(xattr_ref);
 406
 407         xattr_ref->dirty = false;
 408         return ret;
 409 }
 410
 411 static struct ext4_xattr_item *
 412 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 413                        const char *name, size_t name_len)
 414 {
 415         struct ext4_xattr_item tmp = {
 416                 .name_index = name_index,
 417                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 418                 .name_len = name_len,
 419         };
 420         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 421             name_len == 4 &&
 422             !memcmp(name, "data", 4))
 423                 tmp.in_inode = true;
 424
 425         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 426 }
 427
 428 static struct ext4_xattr_item *
 429 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 430                        const char *name, size_t name_len, const void *data,
 431                        size_t data_size)
 432 {
 433         struct ext4_xattr_item *item;
 434         item = ext4_xattr_item_alloc(name_index, name, name_len);
 435         if (!item)
 436                 return NULL;
 437
 438         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 439                 EXT4_XATTR_LEN(item->name_len)
 440                         >
 441             ext4_xattr_inode_space(xattr_ref) -
 442                 sizeof(struct ext4_xattr_ibody_header))
 443                 &&
 444             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 445                 EXT4_XATTR_LEN(item->name_len) >
 446             ext4_xattr_block_space(xattr_ref) -
 447                 sizeof(struct ext4_xattr_header))) {
 448                 ext4_xattr_item_free(item);
 449
 450                 return NULL;
 451         }
 452         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 453                 ext4_xattr_item_free(item);
 454                 return NULL;
 455         }
 456         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 457         xattr_ref->ea_size +=
 458             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 459         xattr_ref->dirty = true;
 460         return item;
 461 }
 462
 463 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 464                                   uint8_t name_index, const char *name,
 465                                   size_t name_len)
 466 {
 467         int ret = ENOENT;
 468         struct ext4_xattr_item *item =
 469             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 470         if (item) {
 471                 if (item == xattr_ref->iter_from)
 472                         xattr_ref->iter_from =
 473                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 474
 475                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 476                                       EXT4_XATTR_LEN(item->name_len);
 477
 478                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 479                 ext4_xattr_item_free(item);
 480                 xattr_ref->dirty = true;
 481                 ret = EOK;
 482         }
 483         return ret;
 484 }
 485
 486 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 487                                   struct ext4_xattr_item *item,
 488                                   size_t new_data_size)
 489 {
 490         int ret = EOK;
 491         size_t old_data_size = item->data_size;
 492         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 493                 EXT4_XATTR_SIZE(new_data_size)
 494                         >
 495             ext4_xattr_inode_space(xattr_ref) -
 496                 sizeof(struct ext4_xattr_ibody_header))
 497                 &&
 498             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 499                 EXT4_XATTR_SIZE(new_data_size)
 500                         >
 501             ext4_xattr_block_space(xattr_ref) -
 502                 sizeof(struct ext4_xattr_header))) {
 503
 504                 return ENOSPC;
 505         }
 506         ret = ext4_xattr_item_resize_data(item, new_data_size);
 507         if (ret != EOK) {
 508                 return ret;
 509         }
 510         xattr_ref->ea_size =
 511             xattr_ref->ea_size -
 512             EXT4_XATTR_SIZE(old_data_size) +
 513             EXT4_XATTR_SIZE(new_data_size);
 514         xattr_ref->dirty = true;
 515         return ret;
 516 }
 517
 518 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 519 {
 520         struct ext4_xattr_item *item, *save_item;
 521         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 522         {
 523                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 524                 ext4_xattr_item_free(item);
 525         }
 526         xattr_ref->ea_size = 0;
 527 }
 528
 529 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 530 {
 531         int ret = EOK;
 532
 533         ext4_fsblk_t xattr_block = 0;
 534         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 535                                               &xattr_ref->fs->sb);
 536         if (!xattr_block) {
 537                 ext4_fsblk_t goal =
 538                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 539
 540                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 541                                               goal,
 542                                               &xattr_block);
 543                 if (ret != EOK)
 544                         goto Finish;
 545
 546                 ret = ext4_trans_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 547                                      xattr_block);
 548                 if (ret != EOK) {
 549                         ext4_balloc_free_block(xattr_ref->inode_ref,
 550                                                xattr_block);
 551                         goto Finish;
 552                 }
 553
 554                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 555                                         &xattr_ref->fs->sb, xattr_block);
 556                 xattr_ref->inode_ref->dirty = true;
 557                 xattr_ref->block_loaded = true;
 558         }
 559
 560 Finish:
 561         return ret;
 562 }
 563
 564 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 565 {
 566         ext4_fsblk_t xattr_block;
 567         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 568                                               &xattr_ref->fs->sb);
 569         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 570                                 0);
 571         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 572         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 573         xattr_ref->inode_ref->dirty = true;
 574         xattr_ref->block_loaded = false;
 575 }
 576
 577 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 578 {
 579         struct ext4_xattr_header *block_header = NULL;
 580         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 581
 582         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 583         block_header->h_magic = EXT4_XATTR_MAGIC;
 584         block_header->h_refcount = to_le32(1);
 585         block_header->h_blocks = to_le32(1);
 586 }
 587
 588 static void
 589 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 590                            struct ext4_xattr_ibody_header *ibody_header,
 591                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 592 {
 593         entry->e_name_len = to_le32(item->name_len);
 594         entry->e_name_index = item->name_index;
 595         entry->e_value_offs =
 596             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 597         entry->e_value_block = 0;
 598         entry->e_value_size = item->data_size;
 599 }
 600
 601 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 602                                        struct ext4_xattr_header *block_header,
 603                                        struct ext4_xattr_entry *block_entry,
 604                                        void *block_data_ptr)
 605 {
 606         block_entry->e_name_len = to_le32(item->name_len);
 607         block_entry->e_name_index = item->name_index;
 608         block_entry->e_value_offs =
 609             (char *)block_data_ptr - (char *)block_header;
 610         block_entry->e_value_block = 0;
 611         block_entry->e_value_size = item->data_size;
 612 }
 613
 614 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 615 {
 616         int ret = EOK;
 617         bool block_modified = false;
 618         void *ibody_data = NULL;
 619         void *block_data = NULL;
 620         struct ext4_xattr_item *item, *save_item;
 621         size_t inode_size_rem, block_size_rem;
 622         struct ext4_xattr_ibody_header *ibody_header = NULL;
 623         struct ext4_xattr_header *block_header = NULL;
 624         struct ext4_xattr_entry *entry = NULL;
 625         struct ext4_xattr_entry *block_entry = NULL;
 626
 627         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 628         block_size_rem = ext4_xattr_block_space(xattr_ref);
 629         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 630                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 631                 entry = EXT4_XATTR_IFIRST(ibody_header);
 632         }
 633
 634         if (!xattr_ref->dirty)
 635                 goto Finish;
 636         /* If there are enough spaces in the ibody EA table.*/
 637         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 638                 memset(ibody_header, 0, inode_size_rem);
 639                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 640                 ibody_data = (char *)ibody_header + inode_size_rem;
 641                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 642
 643                 xattr_ref->inode_ref->dirty = true;
 644         }
 645         /* If we need an extra block to hold the EA entries*/
 646         if (xattr_ref->ea_size > inode_size_rem) {
 647                 if (!xattr_ref->block_loaded) {
 648                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 649                         if (ret != EOK)
 650                                 goto Finish;
 651                 }
 652                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 653                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 654                 ext4_xattr_set_block_header(xattr_ref);
 655                 block_data = (char *)block_header + block_size_rem;
 656                 block_size_rem -= sizeof(struct ext4_xattr_header);
 657
 658                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 659         } else {
 660                 /* We don't need an extra block.*/
 661                 if (xattr_ref->block_loaded) {
 662                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 663                         block_header->h_refcount =
 664                             to_le32(to_le32(block_header->h_refcount) - 1);
 665                         if (!block_header->h_refcount) {
 666                                 ext4_xattr_try_free_block(xattr_ref);
 667                                 block_header = NULL;
 668                         } else {
 669                                 block_entry =
 670                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 671                                 block_data =
 672                                     (char *)block_header + block_size_rem;
 673                                 block_size_rem -=
 674                                     sizeof(struct ext4_xattr_header);
 675                                 ext4_inode_set_file_acl(
 676                                     xattr_ref->inode_ref->inode,
 677                                     &xattr_ref->fs->sb, 0);
 678
 679                                 xattr_ref->inode_ref->dirty = true;
 680                                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 681                         }
 682                 }
 683         }
 684         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 685         {
 686                 if (EXT4_XATTR_SIZE(item->data_size) +
 687                         EXT4_XATTR_LEN(item->name_len) <=
 688                     inode_size_rem) {
 689                         ibody_data = (char *)ibody_data -
 690                                      EXT4_XATTR_SIZE(item->data_size);
 691                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 692                                                    ibody_data);
 693                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 694                                item->name_len);
 695                         memcpy(ibody_data, item->data, item->data_size);
 696                         entry = EXT4_XATTR_NEXT(entry);
 697                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 698                                           EXT4_XATTR_LEN(item->name_len);
 699
 700                         xattr_ref->inode_ref->dirty = true;
 701                         continue;
 702                 }
 703                 if (EXT4_XATTR_SIZE(item->data_size) +
 704                         EXT4_XATTR_LEN(item->name_len) >
 705                     block_size_rem) {
 706                         ret = ENOSPC;
 707                         goto Finish;
 708                 }
 709                 block_data =
 710                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 711                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 712                                            block_data);
 713                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 714                        item->name_len);
 715                 memcpy(block_data, item->data, item->data_size);
 716                 block_entry = EXT4_XATTR_NEXT(block_entry);
 717                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 718                                   EXT4_XATTR_LEN(item->name_len);
 719
 720                 block_modified = true;
 721         }
 722         xattr_ref->dirty = false;
 723         if (block_modified) {
 724                 ext4_xattr_rehash(block_header,
 725                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 726                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 727                                               xattr_ref->block.lb_id,
 728                                               block_header);
 729                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 730         }
 731
 732 Finish:
 733         return ret;
 734 }
 735
 736 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 737                            int (*iter)(struct ext4_xattr_ref *ref,
 738                                      struct ext4_xattr_item *item))
 739 {
 740         struct ext4_xattr_item *item;
 741         if (!ref->iter_from)
 742                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 743
 744         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 745         {
 746                 int ret = EXT4_XATTR_ITERATE_CONT;
 747                 if (iter)
 748                         iter(ref, item);
 749
 750                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 751                         if (ret == EXT4_XATTR_ITERATE_STOP)
 752                                 ref->iter_from = NULL;
 753
 754                         break;
 755                 }
 756         }
 757 }
 758
 759 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 760 {
 761         ref->iter_from = NULL;
 762 }
 763
 764 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 765                       const char *name, size_t name_len, const void *data,
 766                       size_t data_size, bool replace)
 767 {
 768         int ret = EOK;
 769         struct ext4_xattr_item *item =
 770             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 771         if (replace) {
 772                 if (!item) {
 773                         ret = ENODATA;
 774                         goto Finish;
 775                 }
 776                 if (item->data_size != data_size)
 777                         ret = ext4_xattr_resize_item(ref, item, data_size);
 778
 779                 if (ret != EOK) {
 780                         goto Finish;
 781                 }
 782                 memcpy(item->data, data, data_size);
 783         } else {
 784                 if (item) {
 785                         ret = EEXIST;
 786                         goto Finish;
 787                 }
 788                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 789                                               data, data_size);
 790                 if (!item)
 791                         ret = ENOMEM;
 792         }
 793 Finish:
 794         return ret;
 795 }
 796
 797 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 798                          const char *name, size_t name_len)
 799 {
 800         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 801 }
 802
 803 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 804                       const char *name, size_t name_len, void *buf,
 805                       size_t buf_size, size_t *data_size)
 806 {
 807         int ret = EOK;
 808         size_t item_size = 0;
 809         struct ext4_xattr_item *item =
 810             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 811
 812         if (!item) {
 813                 ret = ENODATA;
 814                 goto Finish;
 815         }
 816         item_size = item->data_size;
 817         if (buf_size > item_size)
 818                 buf_size = item_size;
 819
 820         if (buf)
 821                 memcpy(buf, item->data, buf_size);
 822
 823 Finish:
 824         if (data_size)
 825                 *data_size = item_size;
 826
 827         return ret;
 828 }
 829
 830 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 831                           struct ext4_xattr_ref *ref)
 832 {
 833         int rc;
 834         ext4_fsblk_t xattr_block;
 835         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 836         RB_INIT(&ref->root);
 837         ref->ea_size = 0;
 838         ref->iter_from = NULL;
 839         if (xattr_block) {
 840                 rc = ext4_trans_block_get(fs->bdev, &ref->block, xattr_block);
 841                 if (rc != EOK)
 842                         return EIO;
 843
 844                 ref->block_loaded = true;
 845         } else
 846                 ref->block_loaded = false;
 847
 848         ref->inode_ref = inode_ref;
 849         ref->fs = fs;
 850
 851         rc = ext4_xattr_fetch(ref);
 852         if (rc != EOK) {
 853                 ext4_xattr_purge_items(ref);
 854                 if (xattr_block)
 855                         ext4_block_set(fs->bdev, &inode_ref->block);
 856
 857                 ref->block_loaded = false;
 858                 return rc;
 859         }
 860         return EOK;
 861 }
 862
 863 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 864 {
 865         ext4_xattr_write_to_disk(ref);
 866         if (ref->block_loaded) {
 867                 ext4_block_set(ref->fs->bdev, &ref->block);
 868                 ref->block_loaded = false;
 869         }
 870         ext4_xattr_purge_items(ref);
 871         ref->inode_ref = NULL;
 872         ref->fs = NULL;
 873 }
 874
 875 struct xattr_prefix {
 876         const char *prefix;
 877         uint8_t name_index;
 878 };
 879
 880 static const struct xattr_prefix prefix_tbl[] = {
 881     {"user.", EXT4_XATTR_INDEX_USER},
 882     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 883     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 884     {"trusted.", EXT4_XATTR_INDEX_TRUSTED},
 885     {"security.", EXT4_XATTR_INDEX_SECURITY},
 886     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 887     {"system.richacl", EXT4_XATTR_INDEX_RICHACL},
 888     {NULL, 0},
 889 };
 890
 891 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 892                               uint8_t *name_index, size_t *name_len)
 893 {
 894         int i;
 895         ext4_assert(name_index);
 896         if (!full_name_len) {
 897                 if (name_len)
 898                         *name_len = 0;
 899
 900                 return NULL;
 901         }
 902
 903         for (i = 0; prefix_tbl[i].prefix; i++) {
 904                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 905                 if (full_name_len >= prefix_len &&
 906                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 907                         *name_index = prefix_tbl[i].name_index;
 908                         if (name_len)
 909                                 *name_len = full_name_len - prefix_len;
 910
 911                         return full_name + prefix_len;
 912                 }
 913         }
 914         if (name_len)
 915                 *name_len = 0;
 916
 917         return NULL;
 918 }
 919
 920 const char *ext4_get_xattr_name_prefix(uint8_t name_index,
 921                                        size_t *ret_prefix_len)
 922 {
 923         int i;
 924
 925         for (i = 0; prefix_tbl[i].prefix; i++) {
 926                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 927                 if (prefix_tbl[i].name_index == name_index) {
 928                         if (ret_prefix_len)
 929                                 *ret_prefix_len = prefix_len;
 930
 931                         return prefix_tbl[i].prefix;
 932                 }
 933         }
 934         if (ret_prefix_len)
 935                 *ret_prefix_len = 0;
 936
 937         return NULL;
 938 }
 939
 940 /**
 941  * @}
 942  */