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  *
   6  * HelenOS:
   7  * Copyright (c) 2012 Martin Sucha
   8  * Copyright (c) 2012 Frantisek Princ
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  *
  15  * - Redistributions of source code must retain the above copyright
  16  *   notice, this list of conditions and the following disclaimer.
  17  * - Redistributions in binary form must reproduce the above copyright
  18  *   notice, this list of conditions and the following disclaimer in the
  19  *   documentation and/or other materials provided with the distribution.
  20  * - The name of the author may not be used to endorse or promote products
  21  *   derived from this software without specific prior written permission.
  22  *
  23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  24  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  25  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  26  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  30  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 /** @addtogroup lwext4
  36  * @{
  37  */
  38 /**
  39  * @file  ext4_xattr.c
  40  * @brief Extended Attribute manipulation.
  41  */
  42
  43 #include "ext4_config.h"
  44 #include "ext4_types.h"
  45 #include "ext4_fs.h"
  46 #include "ext4_errno.h"
  47 #include "ext4_blockdev.h"
  48 #include "ext4_super.h"
  49 #include "ext4_debug.h"
  50 #include "ext4_block_group.h"
  51 #include "ext4_balloc.h"
  52 #include "ext4_inode.h"
  53 #include "ext4_extent.h"
  54
  55 #include <string.h>
  56 #include <stdlib.h>
  57
  58 /**
  59  * @file  ext4_xattr.c
  60  * @brief Extended Attribute Manipulation
  61  */
  62
  63 #define NAME_HASH_SHIFT 5
  64 #define VALUE_HASH_SHIFT 16
  65
  66 static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
  67                                            struct ext4_xattr_entry *entry)
  68 {
  69         uint32_t hash = 0;
  70         char *name = EXT4_XATTR_NAME(entry);
  71         int n;
  72
  73         for (n = 0; n < entry->e_name_len; n++) {
  74                 hash = (hash << NAME_HASH_SHIFT) ^
  75                        (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
  76         }
  77
  78         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
  79                 uint32_t *value =
  80                     (uint32_t *)((char *)header + to_le16(entry->e_value_offs));
  81                 for (n = (to_le32(entry->e_value_size) + EXT4_XATTR_ROUND) >>
  82                          EXT4_XATTR_PAD_BITS;
  83                      n; n--) {
  84                         hash = (hash << VALUE_HASH_SHIFT) ^
  85                                (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
  86                                to_le32(*value++);
  87                 }
  88         }
  89         entry->e_hash = to_le32(hash);
  90 }
  91
  92 #define BLOCK_HASH_SHIFT 16
  93
  94 /*
  95  * ext4_xattr_rehash()
  96  *
  97  * Re-compute the extended attribute hash value after an entry has changed.
  98  */
  99 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
 100                               struct ext4_xattr_entry *entry)
 101 {
 102         struct ext4_xattr_entry *here;
 103         uint32_t hash = 0;
 104
 105         ext4_xattr_compute_hash(header, entry);
 106         here = EXT4_XATTR_ENTRY(header + 1);
 107         while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
 108                 if (!here->e_hash) {
 109                         /* Block is not shared if an entry's hash value == 0 */
 110                         hash = 0;
 111                         break;
 112                 }
 113                 hash = (hash << BLOCK_HASH_SHIFT) ^
 114                        (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
 115                        to_le32(here->e_hash);
 116                 here = EXT4_XATTR_NEXT(here);
 117         }
 118         header->h_hash = to_le32(hash);
 119 }
 120
 121 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 122                                struct ext4_xattr_item *b)
 123 {
 124         int result;
 125         result = a->name_index - b->name_index;
 126         if (result)
 127                 return result;
 128
 129         result = a->name_len - b->name_len;
 130         if (result)
 131                 return result;
 132
 133         return memcmp(a->name, b->name, a->name_len);
 134 }
 135
 136 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 137                      ext4_xattr_item_cmp, static inline)
 138
 139 static struct ext4_xattr_item *
 140 ext4_xattr_item_alloc(uint8_t name_index, char *name, size_t name_len)
 141 {
 142         struct ext4_xattr_item *item;
 143         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 144         if (!item)
 145                 return NULL;
 146
 147         item->name_index = name_index;
 148         item->name = (char *)(item + 1);
 149         item->name_len = name_len;
 150         item->data = NULL;
 151         item->data_size = 0;
 152
 153         memset(&item->node, 0, sizeof(item->node));
 154         memcpy(item->name, name, name_len);
 155
 156         return item;
 157 }
 158
 159 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 160                                       void *orig_data, size_t data_size)
 161 {
 162         void *data = NULL;
 163         ext4_assert(!item->data);
 164         data = malloc(data_size);
 165         if (!data)
 166                 return ENOMEM;
 167
 168         if (orig_data)
 169                 memcpy(data, orig_data, data_size);
 170
 171         item->data = data;
 172         item->data_size = data_size;
 173         return EOK;
 174 }
 175
 176 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 177 {
 178         ext4_assert(item->data);
 179         free(item->data);
 180         item->data = NULL;
 181         item->data_size = 0;
 182 }
 183
 184 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 185                                        size_t new_data_size)
 186 {
 187         if (new_data_size != item->data_size) {
 188                 void *new_data;
 189                 new_data = realloc(item->data, new_data_size);
 190                 if (!new_data)
 191                         return ENOMEM;
 192
 193                 item->data = new_data;
 194                 item->data_size = new_data_size;
 195         }
 196         return EOK;
 197 }
 198
 199 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 200 {
 201         if (item->data)
 202                 ext4_xattr_item_free_data(item);
 203
 204         free(item);
 205 }
 206
 207 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 208                                    struct ext4_xattr_entry *entry,
 209                                    bool in_inode)
 210 {
 211         void *ret;
 212         if (in_inode) {
 213                 struct ext4_xattr_ibody_header *header;
 214                 struct ext4_xattr_entry *first_entry;
 215                 uint16_t inode_size =
 216                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 217                 header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 218                 first_entry = EXT4_XATTR_IFIRST(header);
 219
 220                 ret = (void *)((char *)first_entry +
 221                                to_le16(entry->e_value_offs));
 222                 if ((char *)ret +
 223                         EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 224                         (char *)xattr_ref->inode_ref->inode >
 225                     inode_size)
 226                         ret = NULL;
 227
 228         } else {
 229                 int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 230                 ret = (void *)((char *)xattr_ref->block.data +
 231                                to_le16(entry->e_value_offs));
 232                 if ((char *)ret +
 233                         EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 234                         (char *)xattr_ref->block.data >
 235                     block_size)
 236                         ret = NULL;
 237         }
 238         return ret;
 239 }
 240
 241 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 242 {
 243         int ret = EOK;
 244         size_t size_rem;
 245         void *data;
 246         struct ext4_xattr_entry *entry = NULL;
 247
 248         ext4_assert(xattr_ref->block.data);
 249         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 250
 251         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 252         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 253              entry = EXT4_XATTR_NEXT(entry),
 254              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 255                 struct ext4_xattr_item *item;
 256                 char *e_name = EXT4_XATTR_NAME(entry);
 257
 258                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 259                 if (!data) {
 260                         ret = EIO;
 261                         goto Finish;
 262                 }
 263
 264                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 265                                              (size_t)entry->e_name_len);
 266                 if (!item) {
 267                         ret = ENOMEM;
 268                         goto Finish;
 269                 }
 270                 if (ext4_xattr_item_alloc_data(
 271                         item, data, to_le32(entry->e_value_size)) != EOK) {
 272                         ext4_xattr_item_free(item);
 273                         ret = ENOMEM;
 274                         goto Finish;
 275                 }
 276                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 277                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 278                                       EXT4_XATTR_LEN(item->name_len);
 279         }
 280
 281 Finish:
 282         return ret;
 283 }
 284
 285 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 286 {
 287         void *data;
 288         size_t size_rem;
 289         int ret = EOK;
 290         struct ext4_xattr_ibody_header *header = NULL;
 291         struct ext4_xattr_entry *entry = NULL;
 292         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 293
 294         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 295         entry = EXT4_XATTR_IFIRST(header);
 296
 297         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 298                    xattr_ref->inode_ref->inode->extra_isize;
 299         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 300              entry = EXT4_XATTR_NEXT(entry),
 301              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 302                 struct ext4_xattr_item *item;
 303                 char *e_name = EXT4_XATTR_NAME(entry);
 304
 305                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 306                 if (!data) {
 307                         ret = EIO;
 308                         goto Finish;
 309                 }
 310
 311                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 312                                              (size_t)entry->e_name_len);
 313                 if (!item) {
 314                         ret = ENOMEM;
 315                         goto Finish;
 316                 }
 317                 if (ext4_xattr_item_alloc_data(
 318                         item, data, to_le32(entry->e_value_size)) != EOK) {
 319                         ext4_xattr_item_free(item);
 320                         ret = ENOMEM;
 321                         goto Finish;
 322                 }
 323                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 324                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 325                                       EXT4_XATTR_LEN(item->name_len);
 326         }
 327
 328 Finish:
 329         return ret;
 330 }
 331
 332 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 333 {
 334         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 335         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 336                             xattr_ref->inode_ref->inode->extra_isize;
 337         return size_rem;
 338 }
 339
 340 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 341 {
 342         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 343 }
 344
 345 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 346 {
 347         int ret = EOK;
 348         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 349         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 350                 ret = ext4_xattr_inode_fetch(xattr_ref);
 351                 if (ret != EOK)
 352                         return ret;
 353         }
 354
 355         if (xattr_ref->block_loaded)
 356                 ret = ext4_xattr_block_fetch(xattr_ref);
 357
 358         xattr_ref->dirty = false;
 359         return ret;
 360 }
 361
 362 static struct ext4_xattr_item *
 363 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 364                        char *name, size_t name_len)
 365 {
 366         struct ext4_xattr_item tmp, *ret;
 367         tmp.name_index = name_index;
 368         tmp.name = name;
 369         tmp.name_len = name_len;
 370         ret = RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 371         return ret;
 372 }
 373
 374 static struct ext4_xattr_item *
 375 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 376                        char *name, size_t name_len, void *data,
 377                        size_t data_size)
 378 {
 379         struct ext4_xattr_item *item;
 380         item = ext4_xattr_item_alloc(name_index, name, name_len);
 381         if (!item)
 382                 return NULL;
 383
 384         if (xattr_ref->ea_size + EXT4_XATTR_SIZE(item->data_size) +
 385                 EXT4_XATTR_LEN(item->name_len) >
 386             ext4_xattr_inode_space(xattr_ref) +
 387                 ext4_xattr_block_space(xattr_ref)) {
 388                 ext4_xattr_item_free(item);
 389                 return NULL;
 390         }
 391         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 392                 ext4_xattr_item_free(item);
 393                 return NULL;
 394         }
 395         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 396         xattr_ref->ea_size +=
 397             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 398         xattr_ref->dirty = true;
 399         return item;
 400 }
 401
 402 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 403                                   uint8_t name_index, char *name,
 404                                   size_t name_len)
 405 {
 406         int ret = ENOENT;
 407         struct ext4_xattr_item *item =
 408             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 409         if (item) {
 410                 if (item == xattr_ref->iter_from)
 411                         xattr_ref->iter_from =
 412                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 413
 414                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 415                 ext4_xattr_item_free(item);
 416                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 417                                       EXT4_XATTR_LEN(item->name_len);
 418                 xattr_ref->dirty = true;
 419                 ret = EOK;
 420         }
 421         return ret;
 422 }
 423
 424 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 425                                   struct ext4_xattr_item *item,
 426                                   size_t new_data_size)
 427 {
 428         int ret = EOK;
 429         if (xattr_ref->ea_size - EXT4_XATTR_SIZE(item->data_size) +
 430                 EXT4_XATTR_SIZE(new_data_size) >
 431             ext4_xattr_inode_space(xattr_ref) +
 432                 ext4_xattr_block_space(xattr_ref)) {
 433
 434                 return ENOSPC;
 435         }
 436         ret = ext4_xattr_item_resize_data(item, new_data_size);
 437         if (ret != EOK) {
 438                 return ret;
 439         }
 440         xattr_ref->ea_size -=
 441             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_SIZE(new_data_size);
 442         xattr_ref->dirty = true;
 443         return ret;
 444 }
 445
 446 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 447 {
 448         struct ext4_xattr_item *item, *save_item;
 449         uint64_t xattr_block = ext4_inode_get_file_acl(
 450             xattr_ref->inode_ref->inode, &xattr_ref->fs->sb);
 451         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 452         {
 453                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 454                 ext4_xattr_item_free(item);
 455         }
 456         xattr_ref->ea_size = 0;
 457         if (xattr_block)
 458                 xattr_ref->ea_size += sizeof(struct ext4_xattr_header);
 459
 460         if (ext4_xattr_inode_space(xattr_ref) >
 461             sizeof(struct ext4_xattr_ibody_header))
 462                 xattr_ref->ea_size += sizeof(struct ext4_xattr_ibody_header);
 463 }
 464
 465 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 466 {
 467         int ret = EOK;
 468
 469         uint64_t xattr_block = 0;
 470         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 471                                               &xattr_ref->fs->sb);
 472         if (!xattr_block) {
 473                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 474                                               (uint32_t *)&xattr_block);
 475                 if (ret != EOK)
 476                         goto Finish;
 477
 478                 ret = ext4_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 479                                      xattr_block);
 480                 if (ret != EOK) {
 481                         ext4_balloc_free_block(xattr_ref->inode_ref,
 482                                                xattr_block);
 483                         goto Finish;
 484                 }
 485
 486                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 487                                         &xattr_ref->fs->sb, xattr_block);
 488                 xattr_ref->inode_ref->dirty = true;
 489                 xattr_ref->block_loaded = true;
 490                 xattr_ref->ea_size += sizeof(struct ext4_xattr_header);
 491         }
 492
 493 Finish:
 494         return ret;
 495 }
 496
 497 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 498 {
 499         uint64_t xattr_block;
 500         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 501                                               &xattr_ref->fs->sb);
 502         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 503                                 0);
 504         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 505         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 506         xattr_ref->inode_ref->dirty = true;
 507         xattr_ref->block_loaded = false;
 508         xattr_ref->ea_size -= sizeof(struct ext4_xattr_header);
 509 }
 510
 511 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 512 {
 513         struct ext4_xattr_header *block_header = NULL;
 514         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 515
 516         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 517         block_header->h_magic = EXT4_XATTR_MAGIC;
 518         block_header->h_refcount = to_le32(1);
 519         block_header->h_blocks = to_le32(1);
 520 }
 521
 522 static void
 523 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 524                            struct ext4_xattr_ibody_header *ibody_header,
 525                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 526 {
 527         entry->e_name_len = to_le32(item->name_len);
 528         entry->e_name_index = item->name_index;
 529         entry->e_value_offs =
 530             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 531         entry->e_value_block = 0;
 532         entry->e_value_size = item->data_size;
 533 }
 534
 535 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 536                                        struct ext4_xattr_header *block_header,
 537                                        struct ext4_xattr_entry *block_entry,
 538                                        void *block_data_ptr)
 539 {
 540         block_entry->e_name_len = to_le32(item->name_len);
 541         block_entry->e_name_index = item->name_index;
 542         block_entry->e_value_offs =
 543             (char *)block_data_ptr - (char *)block_header;
 544         block_entry->e_value_block = 0;
 545         block_entry->e_value_size = item->data_size;
 546 }
 547
 548 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 549 {
 550         int ret = EOK;
 551         bool block_modified = false;
 552         void *ibody_data, *block_data;
 553         struct ext4_xattr_item *item, *save_item;
 554         size_t inode_size_rem, block_size_rem;
 555         struct ext4_xattr_ibody_header *ibody_header = NULL;
 556         struct ext4_xattr_header *block_header = NULL;
 557         struct ext4_xattr_entry *entry = NULL;
 558         struct ext4_xattr_entry *block_entry = NULL;
 559
 560         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 561         block_size_rem = ext4_xattr_block_space(xattr_ref);
 562         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 563                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 564                 entry = EXT4_XATTR_IFIRST(ibody_header);
 565         }
 566
 567         if (!xattr_ref->dirty)
 568                 goto Finish;
 569         /* If there are enough spaces in the ibody EA table.*/
 570         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 571                 memset(ibody_header, 0, inode_size_rem);
 572                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 573                 ibody_data = (char *)ibody_header + inode_size_rem;
 574                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 575
 576                 xattr_ref->inode_ref->dirty = true;
 577         }
 578         /* If we need an extra block to hold the EA entries*/
 579         if (xattr_ref->ea_size > inode_size_rem) {
 580                 if (!xattr_ref->block_loaded) {
 581                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 582                         if (ret != EOK)
 583                                 goto Finish;
 584                 }
 585                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 586                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 587                 ext4_xattr_set_block_header(xattr_ref);
 588                 block_data = (char *)block_header + block_size_rem;
 589                 block_size_rem -= sizeof(struct ext4_xattr_header);
 590
 591                 xattr_ref->block.dirty = true;
 592         } else {
 593                 /* We don't need an extra block.*/
 594                 if (xattr_ref->block_loaded) {
 595                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 596                         block_header->h_refcount =
 597                             to_le32(to_le32(block_header->h_refcount) - 1);
 598                         if (!block_header->h_refcount) {
 599                                 ext4_xattr_try_free_block(xattr_ref);
 600                                 block_header = NULL;
 601                         } else {
 602                                 block_entry =
 603                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 604                                 block_data =
 605                                     (char *)block_header + block_size_rem;
 606                                 block_size_rem -=
 607                                     sizeof(struct ext4_xattr_header);
 608                                 ext4_inode_set_file_acl(
 609                                     xattr_ref->inode_ref->inode,
 610                                     &xattr_ref->fs->sb, 0);
 611
 612                                 xattr_ref->inode_ref->dirty = true;
 613                                 xattr_ref->block.dirty = true;
 614                         }
 615                 }
 616         }
 617         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 618         {
 619                 if (EXT4_XATTR_SIZE(item->data_size) +
 620                         EXT4_XATTR_LEN(item->name_len) <=
 621                     inode_size_rem) {
 622                         ibody_data = (char *)ibody_data -
 623                                      EXT4_XATTR_SIZE(item->data_size);
 624                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 625                                                    ibody_data);
 626                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 627                                item->name_len);
 628                         memcpy(ibody_data, item->data, item->data_size);
 629                         entry = EXT4_XATTR_NEXT(entry);
 630                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 631                                           EXT4_XATTR_LEN(item->name_len);
 632
 633                         xattr_ref->inode_ref->dirty = true;
 634                         continue;
 635                 }
 636                 if (EXT4_XATTR_SIZE(item->data_size) +
 637                         EXT4_XATTR_LEN(item->name_len) >
 638                     block_size_rem) {
 639                         ret = ENOSPC;
 640                         goto Finish;
 641                 }
 642                 block_data =
 643                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 644                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 645                                            block_data);
 646                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 647                        item->name_len);
 648                 memcpy(block_data, item->data, item->data_size);
 649                 block_entry = EXT4_XATTR_NEXT(block_entry);
 650                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 651                                   EXT4_XATTR_LEN(item->name_len);
 652
 653                 block_modified = true;
 654         }
 655         xattr_ref->dirty = false;
 656         if (block_modified) {
 657                 ext4_xattr_rehash(block_header,
 658                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 659                 xattr_ref->block.dirty = true;
 660         }
 661
 662 Finish:
 663         return ret;
 664 }
 665
 666 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 667                            int(iter)(struct ext4_xattr_ref *ref,
 668                                      struct ext4_xattr_item *item))
 669 {
 670         struct ext4_xattr_item *item;
 671         if (!ref->iter_from)
 672                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 673
 674         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 675         {
 676                 int ret = EXT4_XATTR_ITERATE_CONT;
 677                 if (iter)
 678                         iter(ref, item);
 679
 680                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 681                         if (ret == EXT4_XATTR_ITERATE_STOP)
 682                                 ref->iter_from = NULL;
 683
 684                         break;
 685                 }
 686         }
 687 }
 688
 689 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 690 {
 691         ref->iter_from = NULL;
 692 }
 693
 694 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 695                       char *name, size_t name_len, void *data, size_t data_size,
 696                       bool replace)
 697 {
 698         int ret = EOK;
 699         struct ext4_xattr_item *item =
 700             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 701         if (replace) {
 702                 if (!item) {
 703                         ret = ENOATTR;
 704                         goto Finish;
 705                 }
 706                 if (item->data_size != data_size)
 707                         ret = ext4_xattr_resize_item(ref, item, data_size);
 708
 709                 if (ret != EOK) {
 710                         goto Finish;
 711                 }
 712                 memcpy(item->data, data, data_size);
 713         } else {
 714                 if (item) {
 715                         ret = EEXIST;
 716                         goto Finish;
 717                 }
 718                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 719                                               data, data_size);
 720                 if (!item)
 721                         ret = ENOMEM;
 722         }
 723 Finish:
 724         return ret;
 725 }
 726
 727 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 728                          char *name, size_t name_len)
 729 {
 730         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 731 }
 732
 733 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 734                       char *name, size_t name_len, void *buf, size_t buf_size,
 735                       size_t *size_got)
 736 {
 737         int ret = EOK;
 738         size_t item_size = 0;
 739         struct ext4_xattr_item *item =
 740             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 741
 742         if (!item) {
 743                 ret = ENOATTR;
 744                 goto Finish;
 745         }
 746         item_size = item->data_size;
 747         if (buf_size > item_size)
 748                 buf_size = item_size;
 749
 750         if (buf)
 751                 memcpy(buf, item->data, buf_size);
 752
 753 Finish:
 754         if (size_got)
 755                 *size_got = buf_size;
 756
 757         return ret;
 758 }
 759
 760 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 761                           struct ext4_xattr_ref *ref)
 762 {
 763         int rc;
 764         uint64_t xattr_block;
 765         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 766         RB_INIT(&ref->root);
 767         ref->ea_size = 0;
 768         ref->iter_from = NULL;
 769         if (xattr_block) {
 770                 rc = ext4_block_get(fs->bdev, &ref->block, xattr_block);
 771                 if (rc != EOK)
 772                         return EIO;
 773
 774                 ref->ea_size += sizeof(struct ext4_xattr_header);
 775                 ref->block_loaded = true;
 776         } else
 777                 ref->block_loaded = false;
 778
 779         ref->inode_ref = inode_ref;
 780         ref->fs = fs;
 781
 782         if (ext4_xattr_inode_space(ref) >
 783             sizeof(struct ext4_xattr_ibody_header))
 784                 ref->ea_size += sizeof(struct ext4_xattr_ibody_header);
 785
 786         rc = ext4_xattr_fetch(ref);
 787         if (rc != EOK) {
 788                 ext4_xattr_purge_items(ref);
 789                 if (xattr_block)
 790                         ext4_block_set(fs->bdev, &inode_ref->block);
 791
 792                 ref->block_loaded = false;
 793                 return rc;
 794         }
 795         return EOK;
 796 }
 797
 798 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 799 {
 800         ext4_xattr_write_to_disk(ref);
 801         if (ref->block_loaded) {
 802                 ext4_block_set(ref->fs->bdev, &ref->block);
 803                 ref->block_loaded = false;
 804         }
 805         ext4_xattr_purge_items(ref);
 806         ref->inode_ref = NULL;
 807         ref->fs = NULL;
 808 }
 809
 810 struct xattr_prefix {
 811         char *prefix;
 812         uint8_t name_index;
 813 };
 814
 815 static const struct xattr_prefix prefix_tbl[] = {
 816     {"user.", EXT4_XATTR_INDEX_USER},
 817     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 818     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 819     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 820     {NULL, 0},
 821 };
 822
 823 char *ext4_extract_xattr_name(char *full_name, size_t full_name_len,
 824                               uint8_t *name_index, size_t *name_len)
 825 {
 826         int i;
 827         ext4_assert(name_index);
 828         if (!full_name_len)
 829                 return NULL;
 830
 831         for (i = 0; prefix_tbl[i].prefix; i++) {
 832                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 833                 if (full_name_len >= prefix_len &&
 834                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 835                         *name_index = prefix_tbl[i].name_index;
 836                         if (name_len)
 837                                 *name_len = full_name_len - prefix_len;
 838
 839                         return full_name + prefix_len;
 840                 }
 841         }
 842         if (name_len)
 843                 *name_len = 0;
 844
 845         return NULL;
 846 }
 847
 848 /**
 849  * @}
 850  */