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