src/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_misc.h"
  40 #include "ext4_errno.h"
  41 #include "ext4_debug.h"
  42
  43 #include "ext4_fs.h"
  44 #include "ext4_trans.h"
  45 #include "ext4_xattr.h"
  46 #include "ext4_blockdev.h"
  47 #include "ext4_super.h"
  48 #include "ext4_crc32.h"
  49 #include "ext4_block_group.h"
  50 #include "ext4_balloc.h"
  51 #include "ext4_inode.h"
  52
  53 #include <string.h>
  54 #include <stdlib.h>
  55
  56 /**
  57  * @file  ext4_xattr.c
  58  * @brief Extended Attribute Manipulation
  59  */
  60
  61 #define NAME_HASH_SHIFT 5
  62 #define VALUE_HASH_SHIFT 16
  63
  64 static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
  65                                            struct ext4_xattr_entry *entry)
  66 {
  67         uint32_t hash = 0;
  68         char *name = EXT4_XATTR_NAME(entry);
  69         int n;
  70
  71         for (n = 0; n < entry->e_name_len; n++) {
  72                 hash = (hash << NAME_HASH_SHIFT) ^
  73                        (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
  74         }
  75
  76         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
  77                 uint32_t *value =
  78                     (uint32_t *)((char *)header + to_le16(entry->e_value_offs));
  79                 for (n = (to_le32(entry->e_value_size) + EXT4_XATTR_ROUND) >>
  80                          EXT4_XATTR_PAD_BITS;
  81                      n; n--) {
  82                         hash = (hash << VALUE_HASH_SHIFT) ^
  83                                (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
  84                                to_le32(*value++);
  85                 }
  86         }
  87         entry->e_hash = to_le32(hash);
  88 }
  89
  90 #define BLOCK_HASH_SHIFT 16
  91
  92 /*
  93  * ext4_xattr_rehash()
  94  *
  95  * Re-compute the extended attribute hash value after an entry has changed.
  96  */
  97 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
  98                               struct ext4_xattr_entry *entry)
  99 {
 100         struct ext4_xattr_entry *here;
 101         uint32_t hash = 0;
 102
 103         ext4_xattr_compute_hash(header, entry);
 104         here = EXT4_XATTR_ENTRY(header + 1);
 105         while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
 106                 if (!here->e_hash) {
 107                         /* Block is not shared if an entry's hash value == 0 */
 108                         hash = 0;
 109                         break;
 110                 }
 111                 hash = (hash << BLOCK_HASH_SHIFT) ^
 112                        (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
 113                        to_le32(here->e_hash);
 114                 here = EXT4_XATTR_NEXT(here);
 115         }
 116         header->h_hash = to_le32(hash);
 117 }
 118
 119 #if CONFIG_META_CSUM_ENABLE
 120 static uint32_t
 121 ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
 122                           ext4_fsblk_t blocknr,
 123                           struct ext4_xattr_header *header)
 124 {
 125         uint32_t checksum = 0;
 126         uint64_t le64_blocknr = blocknr;
 127         struct ext4_sblock *sb = &inode_ref->fs->sb;
 128
 129         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 130                 uint32_t orig_checksum;
 131
 132                 /* Preparation: temporarily set bg checksum to 0 */
 133                 orig_checksum = header->h_checksum;
 134                 header->h_checksum = 0;
 135                 /* First calculate crc32 checksum against fs uuid */
 136                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 137                                 sizeof(sb->uuid));
 138                 /* Then calculate crc32 checksum block number */
 139                 checksum = ext4_crc32c(checksum, &le64_blocknr,
 140                                      sizeof(le64_blocknr));
 141                 /* Finally calculate crc32 checksum against
 142                  * the entire xattr block */
 143                 checksum = ext4_crc32c(checksum, header,
 144                                    ext4_sb_get_block_size(sb));
 145                 header->h_checksum = orig_checksum;
 146         }
 147         return checksum;
 148 }
 149 #else
 150 #define ext4_xattr_block_checksum(...) 0
 151 #endif
 152
 153 static void
 154 ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
 155                               ext4_fsblk_t blocknr __unused,
 156                               struct ext4_xattr_header *header)
 157 {
 158         struct ext4_sblock *sb = &inode_ref->fs->sb;
 159         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 160                 return;
 161
 162         header->h_checksum =
 163                 ext4_xattr_block_checksum(inode_ref, blocknr, header);
 164 }
 165
 166 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 167                                struct ext4_xattr_item *b)
 168 {
 169         int result;
 170         if (a->in_inode && !b->in_inode)
 171                 return -1;
 172
 173         if (!a->in_inode && b->in_inode)
 174                 return 1;
 175
 176         result = a->name_index - b->name_index;
 177         if (result)
 178                 return result;
 179
 180         result = a->name_len - b->name_len;
 181         if (result)
 182                 return result;
 183
 184         return memcmp(a->name, b->name, a->name_len);
 185 }
 186
 187 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 188                      ext4_xattr_item_cmp, static inline)
 189
 190 static struct ext4_xattr_item *
 191 ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 192 {
 193         struct ext4_xattr_item *item;
 194         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 195         if (!item)
 196                 return NULL;
 197
 198         item->name_index = name_index;
 199         item->name = (char *)(item + 1);
 200         item->name_len = name_len;
 201         item->data = NULL;
 202         item->data_size = 0;
 203
 204         memset(&item->node, 0, sizeof(item->node));
 205         memcpy(item->name, name, name_len);
 206
 207         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 208             name_len == 4 &&
 209             !memcmp(name, "data", 4))
 210                 item->in_inode = true;
 211         else
 212                 item->in_inode = false;
 213
 214         return item;
 215 }
 216
 217 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 218                                       const void *orig_data, size_t data_size)
 219 {
 220         void *data = NULL;
 221         ext4_assert(!item->data);
 222         data = malloc(data_size);
 223         if (!data)
 224                 return ENOMEM;
 225
 226         if (orig_data)
 227                 memcpy(data, orig_data, data_size);
 228
 229         item->data = data;
 230         item->data_size = data_size;
 231         return EOK;
 232 }
 233
 234 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 235 {
 236         ext4_assert(item->data);
 237         free(item->data);
 238         item->data = NULL;
 239         item->data_size = 0;
 240 }
 241
 242 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 243                                        size_t new_data_size)
 244 {
 245         if (new_data_size != item->data_size) {
 246                 void *new_data;
 247                 new_data = realloc(item->data, new_data_size);
 248                 if (!new_data)
 249                         return ENOMEM;
 250
 251                 item->data = new_data;
 252                 item->data_size = new_data_size;
 253         }
 254         return EOK;
 255 }
 256
 257 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 258 {
 259         if (item->data)
 260                 ext4_xattr_item_free_data(item);
 261
 262         free(item);
 263 }
 264
 265 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 266                                    struct ext4_xattr_entry *entry,
 267                                    bool in_inode)
 268 {
 269         char *ret;
 270         if (in_inode) {
 271                 struct ext4_xattr_ibody_header *header;
 272                 struct ext4_xattr_entry *first_entry;
 273                 int16_t inode_size =
 274                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 275                 header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 276                 first_entry = EXT4_XATTR_IFIRST(header);
 277
 278                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 279                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 280                         (char *)xattr_ref->inode_ref->inode > inode_size)
 281                         ret = NULL;
 282
 283                 return ret;
 284
 285         }
 286         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 287         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 288         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 289                         (char *)xattr_ref->block.data > block_size)
 290                 ret = NULL;
 291         return ret;
 292 }
 293
 294 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 295 {
 296         int ret = EOK;
 297         size_t size_rem;
 298         void *data;
 299         struct ext4_xattr_entry *entry = NULL;
 300
 301         ext4_assert(xattr_ref->block.data);
 302         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 303
 304         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 305         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 306              entry = EXT4_XATTR_NEXT(entry),
 307              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 308                 struct ext4_xattr_item *item;
 309                 char *e_name = EXT4_XATTR_NAME(entry);
 310
 311                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 312                 if (!data) {
 313                         ret = EIO;
 314                         goto Finish;
 315                 }
 316
 317                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 318                                              (size_t)entry->e_name_len);
 319                 if (!item) {
 320                         ret = ENOMEM;
 321                         goto Finish;
 322                 }
 323                 if (ext4_xattr_item_alloc_data(
 324                         item, data, to_le32(entry->e_value_size)) != EOK) {
 325                         ext4_xattr_item_free(item);
 326                         ret = ENOMEM;
 327                         goto Finish;
 328                 }
 329                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 330                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 331                                       EXT4_XATTR_LEN(item->name_len);
 332         }
 333
 334 Finish:
 335         return ret;
 336 }
 337
 338 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 339 {
 340         void *data;
 341         size_t size_rem;
 342         int ret = EOK;
 343         struct ext4_xattr_ibody_header *header = NULL;
 344         struct ext4_xattr_entry *entry = NULL;
 345         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 346
 347         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 348         entry = EXT4_XATTR_IFIRST(header);
 349
 350         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 351                    xattr_ref->inode_ref->inode->extra_isize;
 352         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 353              entry = EXT4_XATTR_NEXT(entry),
 354              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 355                 struct ext4_xattr_item *item;
 356                 char *e_name = EXT4_XATTR_NAME(entry);
 357
 358                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 359                 if (!data) {
 360                         ret = EIO;
 361                         goto Finish;
 362                 }
 363
 364                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 365                                              (size_t)entry->e_name_len);
 366                 if (!item) {
 367                         ret = ENOMEM;
 368                         goto Finish;
 369                 }
 370                 if (ext4_xattr_item_alloc_data(
 371                         item, data, to_le32(entry->e_value_size)) != EOK) {
 372                         ext4_xattr_item_free(item);
 373                         ret = ENOMEM;
 374                         goto Finish;
 375                 }
 376                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 377                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 378                                       EXT4_XATTR_LEN(item->name_len);
 379         }
 380
 381 Finish:
 382         return ret;
 383 }
 384
 385 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 386 {
 387         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 388         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 389                             xattr_ref->inode_ref->inode->extra_isize;
 390         return size_rem;
 391 }
 392
 393 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 394 {
 395         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 396 }
 397
 398 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 399 {
 400         int ret = EOK;
 401         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 402         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 403                 ret = ext4_xattr_inode_fetch(xattr_ref);
 404                 if (ret != EOK)
 405                         return ret;
 406         }
 407
 408         if (xattr_ref->block_loaded)
 409                 ret = ext4_xattr_block_fetch(xattr_ref);
 410
 411         xattr_ref->dirty = false;
 412         return ret;
 413 }
 414
 415 static struct ext4_xattr_item *
 416 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 417                        const char *name, size_t name_len)
 418 {
 419         struct ext4_xattr_item tmp = {
 420                 .name_index = name_index,
 421                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 422                 .name_len = name_len,
 423         };
 424         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 425             name_len == 4 &&
 426             !memcmp(name, "data", 4))
 427                 tmp.in_inode = true;
 428
 429         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 430 }
 431
 432 static struct ext4_xattr_item *
 433 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 434                        const char *name, size_t name_len, const void *data,
 435                        size_t data_size)
 436 {
 437         struct ext4_xattr_item *item;
 438         item = ext4_xattr_item_alloc(name_index, name, name_len);
 439         if (!item)
 440                 return NULL;
 441
 442         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 443                 EXT4_XATTR_LEN(item->name_len)
 444                         >
 445             ext4_xattr_inode_space(xattr_ref) -
 446                 sizeof(struct ext4_xattr_ibody_header))
 447                 &&
 448             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 449                 EXT4_XATTR_LEN(item->name_len) >
 450             ext4_xattr_block_space(xattr_ref) -
 451                 sizeof(struct ext4_xattr_header))) {
 452                 ext4_xattr_item_free(item);
 453
 454                 return NULL;
 455         }
 456         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 457                 ext4_xattr_item_free(item);
 458                 return NULL;
 459         }
 460         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 461         xattr_ref->ea_size +=
 462             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 463         xattr_ref->dirty = true;
 464         return item;
 465 }
 466
 467 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 468                                   uint8_t name_index, const char *name,
 469                                   size_t name_len)
 470 {
 471         int ret = ENOENT;
 472         struct ext4_xattr_item *item =
 473             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 474         if (item) {
 475                 if (item == xattr_ref->iter_from)
 476                         xattr_ref->iter_from =
 477                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 478
 479                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 480                                       EXT4_XATTR_LEN(item->name_len);
 481
 482                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 483                 ext4_xattr_item_free(item);
 484                 xattr_ref->dirty = true;
 485                 ret = EOK;
 486         }
 487         return ret;
 488 }
 489
 490 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 491                                   struct ext4_xattr_item *item,
 492                                   size_t new_data_size)
 493 {
 494         int ret = EOK;
 495         size_t old_data_size = item->data_size;
 496         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 497                 EXT4_XATTR_SIZE(new_data_size)
 498                         >
 499             ext4_xattr_inode_space(xattr_ref) -
 500                 sizeof(struct ext4_xattr_ibody_header))
 501                 &&
 502             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 503                 EXT4_XATTR_SIZE(new_data_size)
 504                         >
 505             ext4_xattr_block_space(xattr_ref) -
 506                 sizeof(struct ext4_xattr_header))) {
 507
 508                 return ENOSPC;
 509         }
 510         ret = ext4_xattr_item_resize_data(item, new_data_size);
 511         if (ret != EOK) {
 512                 return ret;
 513         }
 514         xattr_ref->ea_size =
 515             xattr_ref->ea_size -
 516             EXT4_XATTR_SIZE(old_data_size) +
 517             EXT4_XATTR_SIZE(new_data_size);
 518         xattr_ref->dirty = true;
 519         return ret;
 520 }
 521
 522 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 523 {
 524         struct ext4_xattr_item *item, *save_item;
 525         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 526         {
 527                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 528                 ext4_xattr_item_free(item);
 529         }
 530         xattr_ref->ea_size = 0;
 531 }
 532
 533 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 534 {
 535         int ret = EOK;
 536
 537         ext4_fsblk_t xattr_block = 0;
 538         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 539                                               &xattr_ref->fs->sb);
 540         if (!xattr_block) {
 541                 ext4_fsblk_t goal =
 542                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 543
 544                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 545                                               goal,
 546                                               &xattr_block);
 547                 if (ret != EOK)
 548                         goto Finish;
 549
 550                 ret = ext4_trans_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 551                                      xattr_block);
 552                 if (ret != EOK) {
 553                         ext4_balloc_free_block(xattr_ref->inode_ref,
 554                                                xattr_block);
 555                         goto Finish;
 556                 }
 557
 558                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 559                                         &xattr_ref->fs->sb, xattr_block);
 560                 xattr_ref->inode_ref->dirty = true;
 561                 xattr_ref->block_loaded = true;
 562         }
 563
 564 Finish:
 565         return ret;
 566 }
 567
 568 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 569 {
 570         ext4_fsblk_t xattr_block;
 571         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 572                                               &xattr_ref->fs->sb);
 573         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 574                                 0);
 575         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 576         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 577         xattr_ref->inode_ref->dirty = true;
 578         xattr_ref->block_loaded = false;
 579 }
 580
 581 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 582 {
 583         struct ext4_xattr_header *block_header = NULL;
 584         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 585
 586         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 587         block_header->h_magic = EXT4_XATTR_MAGIC;
 588         block_header->h_refcount = to_le32(1);
 589         block_header->h_blocks = to_le32(1);
 590 }
 591
 592 static void
 593 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 594                            struct ext4_xattr_ibody_header *ibody_header,
 595                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 596 {
 597         entry->e_name_len = (uint8_t)item->name_len;
 598         entry->e_name_index = item->name_index;
 599         entry->e_value_offs =
 600             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 601         entry->e_value_block = 0;
 602         entry->e_value_size = item->data_size;
 603 }
 604
 605 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 606                                        struct ext4_xattr_header *block_header,
 607                                        struct ext4_xattr_entry *block_entry,
 608                                        void *block_data_ptr)
 609 {
 610         block_entry->e_name_len = (uint8_t)item->name_len;
 611         block_entry->e_name_index = item->name_index;
 612         block_entry->e_value_offs =
 613             (char *)block_data_ptr - (char *)block_header;
 614         block_entry->e_value_block = 0;
 615         block_entry->e_value_size = item->data_size;
 616 }
 617
 618 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 619 {
 620         int ret = EOK;
 621         bool block_modified = false;
 622         void *ibody_data = NULL;
 623         void *block_data = NULL;
 624         struct ext4_xattr_item *item, *save_item;
 625         size_t inode_size_rem, block_size_rem;
 626         struct ext4_xattr_ibody_header *ibody_header = NULL;
 627         struct ext4_xattr_header *block_header = NULL;
 628         struct ext4_xattr_entry *entry = NULL;
 629         struct ext4_xattr_entry *block_entry = NULL;
 630
 631         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 632         block_size_rem = ext4_xattr_block_space(xattr_ref);
 633         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 634                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 635                 entry = EXT4_XATTR_IFIRST(ibody_header);
 636         }
 637
 638         if (!xattr_ref->dirty)
 639                 goto Finish;
 640         /* If there are enough spaces in the ibody EA table.*/
 641         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 642                 memset(ibody_header, 0, inode_size_rem);
 643                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 644                 ibody_data = (char *)ibody_header + inode_size_rem;
 645                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 646
 647                 xattr_ref->inode_ref->dirty = true;
 648         }
 649         /* If we need an extra block to hold the EA entries*/
 650         if (xattr_ref->ea_size > inode_size_rem) {
 651                 if (!xattr_ref->block_loaded) {
 652                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 653                         if (ret != EOK)
 654                                 goto Finish;
 655                 }
 656                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 657                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 658                 ext4_xattr_set_block_header(xattr_ref);
 659                 block_data = (char *)block_header + block_size_rem;
 660                 block_size_rem -= sizeof(struct ext4_xattr_header);
 661
 662                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 663         } else {
 664                 /* We don't need an extra block.*/
 665                 if (xattr_ref->block_loaded) {
 666                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 667                         block_header->h_refcount =
 668                             to_le32(to_le32(block_header->h_refcount) - 1);
 669                         if (!block_header->h_refcount) {
 670                                 ext4_xattr_try_free_block(xattr_ref);
 671                                 block_header = NULL;
 672                         } else {
 673                                 block_entry =
 674                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 675                                 block_data =
 676                                     (char *)block_header + block_size_rem;
 677                                 block_size_rem -=
 678                                     sizeof(struct ext4_xattr_header);
 679                                 ext4_inode_set_file_acl(
 680                                     xattr_ref->inode_ref->inode,
 681                                     &xattr_ref->fs->sb, 0);
 682
 683                                 xattr_ref->inode_ref->dirty = true;
 684                                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 685                         }
 686                 }
 687         }
 688         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 689         {
 690                 if (EXT4_XATTR_SIZE(item->data_size) +
 691                         EXT4_XATTR_LEN(item->name_len) <=
 692                     inode_size_rem) {
 693                         ibody_data = (char *)ibody_data -
 694                                      EXT4_XATTR_SIZE(item->data_size);
 695                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 696                                                    ibody_data);
 697                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 698                                item->name_len);
 699                         memcpy(ibody_data, item->data, item->data_size);
 700                         entry = EXT4_XATTR_NEXT(entry);
 701                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 702                                           EXT4_XATTR_LEN(item->name_len);
 703
 704                         xattr_ref->inode_ref->dirty = true;
 705                         continue;
 706                 }
 707                 if (EXT4_XATTR_SIZE(item->data_size) +
 708                         EXT4_XATTR_LEN(item->name_len) >
 709                     block_size_rem) {
 710                         ret = ENOSPC;
 711                         goto Finish;
 712                 }
 713                 block_data =
 714                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 715                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 716                                            block_data);
 717                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 718                        item->name_len);
 719                 memcpy(block_data, item->data, item->data_size);
 720                 block_entry = EXT4_XATTR_NEXT(block_entry);
 721                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 722                                   EXT4_XATTR_LEN(item->name_len);
 723
 724                 block_modified = true;
 725         }
 726         xattr_ref->dirty = false;
 727         if (block_modified) {
 728                 ext4_xattr_rehash(block_header,
 729                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 730                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 731                                               xattr_ref->block.lb_id,
 732                                               block_header);
 733                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 734         }
 735
 736 Finish:
 737         return ret;
 738 }
 739
 740 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 741                            int (*iter)(struct ext4_xattr_ref *ref,
 742                                      struct ext4_xattr_item *item))
 743 {
 744         struct ext4_xattr_item *item;
 745         if (!ref->iter_from)
 746                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 747
 748         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 749         {
 750                 int ret = EXT4_XATTR_ITERATE_CONT;
 751                 if (iter)
 752                         iter(ref, item);
 753
 754                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 755                         if (ret == EXT4_XATTR_ITERATE_STOP)
 756                                 ref->iter_from = NULL;
 757
 758                         break;
 759                 }
 760         }
 761 }
 762
 763 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 764 {
 765         ref->iter_from = NULL;
 766 }
 767
 768 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 769                       const char *name, size_t name_len, const void *data,
 770                       size_t data_size, bool replace)
 771 {
 772         int ret = EOK;
 773         struct ext4_xattr_item *item =
 774             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 775         if (replace) {
 776                 if (!item) {
 777                         ret = ENODATA;
 778                         goto Finish;
 779                 }
 780                 if (item->data_size != data_size)
 781                         ret = ext4_xattr_resize_item(ref, item, data_size);
 782
 783                 if (ret != EOK) {
 784                         goto Finish;
 785                 }
 786                 memcpy(item->data, data, data_size);
 787         } else {
 788                 if (item) {
 789                         ret = EEXIST;
 790                         goto Finish;
 791                 }
 792                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 793                                               data, data_size);
 794                 if (!item)
 795                         ret = ENOMEM;
 796         }
 797 Finish:
 798         return ret;
 799 }
 800
 801 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 802                          const char *name, size_t name_len)
 803 {
 804         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 805 }
 806
 807 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 808                       const char *name, size_t name_len, void *buf,
 809                       size_t buf_size, size_t *data_size)
 810 {
 811         int ret = EOK;
 812         size_t item_size = 0;
 813         struct ext4_xattr_item *item =
 814             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 815
 816         if (!item) {
 817                 ret = ENODATA;
 818                 goto Finish;
 819         }
 820         item_size = item->data_size;
 821         if (buf_size > item_size)
 822                 buf_size = item_size;
 823
 824         if (buf)
 825                 memcpy(buf, item->data, buf_size);
 826
 827 Finish:
 828         if (data_size)
 829                 *data_size = item_size;
 830
 831         return ret;
 832 }
 833
 834 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 835                           struct ext4_xattr_ref *ref)
 836 {
 837         int rc;
 838         ext4_fsblk_t xattr_block;
 839         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 840         RB_INIT(&ref->root);
 841         ref->ea_size = 0;
 842         ref->iter_from = NULL;
 843         if (xattr_block) {
 844                 rc = ext4_trans_block_get(fs->bdev, &ref->block, xattr_block);
 845                 if (rc != EOK)
 846                         return EIO;
 847
 848                 ref->block_loaded = true;
 849         } else
 850                 ref->block_loaded = false;
 851
 852         ref->inode_ref = inode_ref;
 853         ref->fs = fs;
 854
 855         rc = ext4_xattr_fetch(ref);
 856         if (rc != EOK) {
 857                 ext4_xattr_purge_items(ref);
 858                 if (xattr_block)
 859                         ext4_block_set(fs->bdev, &ref->block);
 860
 861                 ref->block_loaded = false;
 862                 return rc;
 863         }
 864         return EOK;
 865 }
 866
 867 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 868 {
 869         ext4_xattr_write_to_disk(ref);
 870         if (ref->block_loaded) {
 871                 ext4_block_set(ref->fs->bdev, &ref->block);
 872                 ref->block_loaded = false;
 873         }
 874         ext4_xattr_purge_items(ref);
 875         ref->inode_ref = NULL;
 876         ref->fs = NULL;
 877 }
 878
 879 struct xattr_prefix {
 880         const char *prefix;
 881         uint8_t name_index;
 882 };
 883
 884 static const struct xattr_prefix prefix_tbl[] = {
 885     {"user.", EXT4_XATTR_INDEX_USER},
 886     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 887     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 888     {"trusted.", EXT4_XATTR_INDEX_TRUSTED},
 889     {"security.", EXT4_XATTR_INDEX_SECURITY},
 890     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 891     {"system.richacl", EXT4_XATTR_INDEX_RICHACL},
 892     {NULL, 0},
 893 };
 894
 895 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 896                               uint8_t *name_index, size_t *name_len,
 897                               bool *found)
 898 {
 899         int i;
 900         ext4_assert(name_index);
 901         ext4_assert(found);
 902
 903         *found = false;
 904
 905         if (!full_name_len) {
 906                 if (name_len)
 907                         *name_len = 0;
 908
 909                 return NULL;
 910         }
 911
 912         for (i = 0; prefix_tbl[i].prefix; i++) {
 913                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 914                 if (full_name_len >= prefix_len &&
 915                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 916                         bool require_name =
 917                                 prefix_tbl[i].prefix[prefix_len - 1] == '.';
 918                         *name_index = prefix_tbl[i].name_index;
 919                         if (name_len)
 920                                 *name_len = full_name_len - prefix_len;
 921
 922                         if (!(full_name_len - prefix_len) && require_name)
 923                                 return NULL;
 924
 925                         *found = true;
 926                         if (require_name)
 927                                 return full_name + prefix_len;
 928
 929                         return NULL;
 930                 }
 931         }
 932         if (name_len)
 933                 *name_len = 0;
 934
 935         return NULL;
 936 }
 937
 938 const char *ext4_get_xattr_name_prefix(uint8_t name_index,
 939                                        size_t *ret_prefix_len)
 940 {
 941         int i;
 942
 943         for (i = 0; prefix_tbl[i].prefix; i++) {
 944                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 945                 if (prefix_tbl[i].name_index == name_index) {
 946                         if (ret_prefix_len)
 947                                 *ret_prefix_len = prefix_len;
 948
 949                         return prefix_tbl[i].prefix;
 950                 }
 951         }
 952         if (ret_prefix_len)
 953                 *ret_prefix_len = 0;
 954
 955         return NULL;
 956 }
 957
 958 /**
 959  * @}
 960  */