lwext4/ext4_xattr.c

   1 /*
   2  * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com)
   3  * Copyright (c) 2015 Kaho Ng (ngkaho1234@gmail.com)
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright
  10  *   notice, this list of conditions and the following disclaimer.
  11  * - Redistributions in binary form must reproduce the above copyright
  12  *   notice, this list of conditions and the following disclaimer in the
  13  *   documentation and/or other materials provided with the distribution.
  14  * - The name of the author may not be used to endorse or promote products
  15  *   derived from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 /** @addtogroup lwext4
  30  * @{
  31  */
  32 /**
  33  * @file  ext4_xattr.c
  34  * @brief Extended Attribute manipulation.
  35  */
  36
  37 #include "ext4_config.h"
  38 #include "ext4_types.h"
  39 #include "ext4_fs.h"
  40 #include "ext4_errno.h"
  41 #include "ext4_blockdev.h"
  42 #include "ext4_super.h"
  43 #include "ext4_crc32c.h"
  44 #include "ext4_debug.h"
  45 #include "ext4_block_group.h"
  46 #include "ext4_balloc.h"
  47 #include "ext4_inode.h"
  48
  49 #include <string.h>
  50 #include <stdlib.h>
  51
  52 /**
  53  * @file  ext4_xattr.c
  54  * @brief Extended Attribute Manipulation
  55  */
  56
  57 #define NAME_HASH_SHIFT 5
  58 #define VALUE_HASH_SHIFT 16
  59
  60 static inline void ext4_xattr_compute_hash(struct ext4_xattr_header *header,
  61                                            struct ext4_xattr_entry *entry)
  62 {
  63         uint32_t hash = 0;
  64         char *name = EXT4_XATTR_NAME(entry);
  65         int n;
  66
  67         for (n = 0; n < entry->e_name_len; n++) {
  68                 hash = (hash << NAME_HASH_SHIFT) ^
  69                        (hash >> (8 * sizeof(hash) - NAME_HASH_SHIFT)) ^ *name++;
  70         }
  71
  72         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
  73                 uint32_t *value =
  74                     (uint32_t *)((char *)header + to_le16(entry->e_value_offs));
  75                 for (n = (to_le32(entry->e_value_size) + EXT4_XATTR_ROUND) >>
  76                          EXT4_XATTR_PAD_BITS;
  77                      n; n--) {
  78                         hash = (hash << VALUE_HASH_SHIFT) ^
  79                                (hash >> (8 * sizeof(hash) - VALUE_HASH_SHIFT)) ^
  80                                to_le32(*value++);
  81                 }
  82         }
  83         entry->e_hash = to_le32(hash);
  84 }
  85
  86 #define BLOCK_HASH_SHIFT 16
  87
  88 /*
  89  * ext4_xattr_rehash()
  90  *
  91  * Re-compute the extended attribute hash value after an entry has changed.
  92  */
  93 static void ext4_xattr_rehash(struct ext4_xattr_header *header,
  94                               struct ext4_xattr_entry *entry)
  95 {
  96         struct ext4_xattr_entry *here;
  97         uint32_t hash = 0;
  98
  99         ext4_xattr_compute_hash(header, entry);
 100         here = EXT4_XATTR_ENTRY(header + 1);
 101         while (!EXT4_XATTR_IS_LAST_ENTRY(here)) {
 102                 if (!here->e_hash) {
 103                         /* Block is not shared if an entry's hash value == 0 */
 104                         hash = 0;
 105                         break;
 106                 }
 107                 hash = (hash << BLOCK_HASH_SHIFT) ^
 108                        (hash >> (8 * sizeof(hash) - BLOCK_HASH_SHIFT)) ^
 109                        to_le32(here->e_hash);
 110                 here = EXT4_XATTR_NEXT(here);
 111         }
 112         header->h_hash = to_le32(hash);
 113 }
 114
 115 #if CONFIG_META_CSUM_ENABLE
 116 static uint32_t
 117 ext4_xattr_block_checksum(struct ext4_inode_ref *inode_ref,
 118                           ext4_fsblk_t blocknr,
 119                           struct ext4_xattr_header *header)
 120 {
 121         uint32_t checksum = 0;
 122         uint64_t le64_blocknr = blocknr;
 123         struct ext4_sblock *sb = &inode_ref->fs->sb;
 124
 125         if (ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM)) {
 126                 uint32_t orig_checksum;
 127
 128                 /* Preparation: temporarily set bg checksum to 0 */
 129                 orig_checksum = header->h_checksum;
 130                 header->h_checksum = 0;
 131                 /* First calculate crc32 checksum against fs uuid */
 132                 checksum = ext4_crc32c(EXT4_CRC32_INIT, sb->uuid,
 133                                 sizeof(sb->uuid));
 134                 /* Then calculate crc32 checksum block number */
 135                 checksum = ext4_crc32c(checksum, &le64_blocknr,
 136                                      sizeof(le64_blocknr));
 137                 /* Finally calculate crc32 checksum against
 138                  * the entire xattr block */
 139                 checksum = ext4_crc32c(checksum, header,
 140                                    ext4_sb_get_block_size(sb));
 141                 header->h_checksum = orig_checksum;
 142         }
 143         return checksum;
 144 }
 145 #else
 146 #define ext4_xattr_block_checksum(...) 0
 147 #endif
 148
 149 static void
 150 ext4_xattr_set_block_checksum(struct ext4_inode_ref *inode_ref,
 151                               ext4_fsblk_t blocknr __unused,
 152                               struct ext4_xattr_header *header)
 153 {
 154         struct ext4_sblock *sb = &inode_ref->fs->sb;
 155         if (!ext4_sb_feature_ro_com(sb, EXT4_FRO_COM_METADATA_CSUM))
 156                 return;
 157
 158         header->h_checksum =
 159                 ext4_xattr_block_checksum(inode_ref, blocknr, header);
 160 }
 161
 162 static int ext4_xattr_item_cmp(struct ext4_xattr_item *a,
 163                                struct ext4_xattr_item *b)
 164 {
 165         int result;
 166         if (a->in_inode && !b->in_inode)
 167                 return -1;
 168
 169         if (!a->in_inode && b->in_inode)
 170                 return 1;
 171
 172         result = a->name_index - b->name_index;
 173         if (result)
 174                 return result;
 175
 176         result = a->name_len - b->name_len;
 177         if (result)
 178                 return result;
 179
 180         return memcmp(a->name, b->name, a->name_len);
 181 }
 182
 183 RB_GENERATE_INTERNAL(ext4_xattr_tree, ext4_xattr_item, node,
 184                      ext4_xattr_item_cmp, static inline)
 185
 186 static struct ext4_xattr_item *
 187 ext4_xattr_item_alloc(uint8_t name_index, const char *name, size_t name_len)
 188 {
 189         struct ext4_xattr_item *item;
 190         item = malloc(sizeof(struct ext4_xattr_item) + name_len);
 191         if (!item)
 192                 return NULL;
 193
 194         item->name_index = name_index;
 195         item->name = (char *)(item + 1);
 196         item->name_len = name_len;
 197         item->data = NULL;
 198         item->data_size = 0;
 199
 200         memset(&item->node, 0, sizeof(item->node));
 201         memcpy(item->name, name, name_len);
 202
 203         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 204             name_len == 4 &&
 205             !memcmp(name, "data", 4))
 206                 item->in_inode = true;
 207
 208         return item;
 209 }
 210
 211 static int ext4_xattr_item_alloc_data(struct ext4_xattr_item *item,
 212                                       const void *orig_data, size_t data_size)
 213 {
 214         void *data = NULL;
 215         ext4_assert(!item->data);
 216         data = malloc(data_size);
 217         if (!data)
 218                 return ENOMEM;
 219
 220         if (orig_data)
 221                 memcpy(data, orig_data, data_size);
 222
 223         item->data = data;
 224         item->data_size = data_size;
 225         return EOK;
 226 }
 227
 228 static void ext4_xattr_item_free_data(struct ext4_xattr_item *item)
 229 {
 230         ext4_assert(item->data);
 231         free(item->data);
 232         item->data = NULL;
 233         item->data_size = 0;
 234 }
 235
 236 static int ext4_xattr_item_resize_data(struct ext4_xattr_item *item,
 237                                        size_t new_data_size)
 238 {
 239         if (new_data_size != item->data_size) {
 240                 void *new_data;
 241                 new_data = realloc(item->data, new_data_size);
 242                 if (!new_data)
 243                         return ENOMEM;
 244
 245                 item->data = new_data;
 246                 item->data_size = new_data_size;
 247         }
 248         return EOK;
 249 }
 250
 251 static void ext4_xattr_item_free(struct ext4_xattr_item *item)
 252 {
 253         if (item->data)
 254                 ext4_xattr_item_free_data(item);
 255
 256         free(item);
 257 }
 258
 259 static void *ext4_xattr_entry_data(struct ext4_xattr_ref *xattr_ref,
 260                                    struct ext4_xattr_entry *entry,
 261                                    bool in_inode)
 262 {
 263         char *ret;
 264         if (in_inode) {
 265                 struct ext4_xattr_ibody_header *header;
 266                 struct ext4_xattr_entry *first_entry;
 267                 int16_t inode_size =
 268                     ext4_get16(&xattr_ref->fs->sb, inode_size);
 269                 header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 270                 first_entry = EXT4_XATTR_IFIRST(header);
 271
 272                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 273                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 274                         (char *)xattr_ref->inode_ref->inode > inode_size)
 275                         ret = NULL;
 276
 277                 return ret;
 278
 279         }
 280         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 281         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 282         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 283                         (char *)xattr_ref->block.data > block_size)
 284                 ret = NULL;
 285         return ret;
 286 }
 287
 288 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 289 {
 290         int ret = EOK;
 291         size_t size_rem;
 292         void *data;
 293         struct ext4_xattr_entry *entry = NULL;
 294
 295         ext4_assert(xattr_ref->block.data);
 296         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 297
 298         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 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, false);
 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 int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 333 {
 334         void *data;
 335         size_t size_rem;
 336         int ret = EOK;
 337         struct ext4_xattr_ibody_header *header = NULL;
 338         struct ext4_xattr_entry *entry = NULL;
 339         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 340
 341         header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 342         entry = EXT4_XATTR_IFIRST(header);
 343
 344         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 345                    xattr_ref->inode_ref->inode->extra_isize;
 346         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 347              entry = EXT4_XATTR_NEXT(entry),
 348              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 349                 struct ext4_xattr_item *item;
 350                 char *e_name = EXT4_XATTR_NAME(entry);
 351
 352                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 353                 if (!data) {
 354                         ret = EIO;
 355                         goto Finish;
 356                 }
 357
 358                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 359                                              (size_t)entry->e_name_len);
 360                 if (!item) {
 361                         ret = ENOMEM;
 362                         goto Finish;
 363                 }
 364                 if (ext4_xattr_item_alloc_data(
 365                         item, data, to_le32(entry->e_value_size)) != EOK) {
 366                         ext4_xattr_item_free(item);
 367                         ret = ENOMEM;
 368                         goto Finish;
 369                 }
 370                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 371                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 372                                       EXT4_XATTR_LEN(item->name_len);
 373         }
 374
 375 Finish:
 376         return ret;
 377 }
 378
 379 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 380 {
 381         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 382         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 383                             xattr_ref->inode_ref->inode->extra_isize;
 384         return size_rem;
 385 }
 386
 387 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 388 {
 389         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 390 }
 391
 392 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 393 {
 394         int ret = EOK;
 395         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 396         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 397                 ret = ext4_xattr_inode_fetch(xattr_ref);
 398                 if (ret != EOK)
 399                         return ret;
 400         }
 401
 402         if (xattr_ref->block_loaded)
 403                 ret = ext4_xattr_block_fetch(xattr_ref);
 404
 405         xattr_ref->dirty = false;
 406         return ret;
 407 }
 408
 409 static struct ext4_xattr_item *
 410 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 411                        const char *name, size_t name_len)
 412 {
 413         struct ext4_xattr_item tmp = {
 414                 .name_index = name_index,
 415                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 416                 .name_len = name_len,
 417         };
 418         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 419             name_len == 4 &&
 420             !memcmp(name, "data", 4))
 421                 tmp.in_inode = true;
 422
 423         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 424 }
 425
 426 static struct ext4_xattr_item *
 427 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 428                        const char *name, size_t name_len, const void *data,
 429                        size_t data_size)
 430 {
 431         struct ext4_xattr_item *item;
 432         item = ext4_xattr_item_alloc(name_index, name, name_len);
 433         if (!item)
 434                 return NULL;
 435
 436         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 437                 EXT4_XATTR_LEN(item->name_len)
 438                         >
 439             ext4_xattr_inode_space(xattr_ref) -
 440                 sizeof(struct ext4_xattr_ibody_header))
 441                 &&
 442             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 443                 EXT4_XATTR_LEN(item->name_len) >
 444             ext4_xattr_block_space(xattr_ref) -
 445                 sizeof(struct ext4_xattr_header))) {
 446                 ext4_xattr_item_free(item);
 447
 448                 return NULL;
 449         }
 450         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 451                 ext4_xattr_item_free(item);
 452                 return NULL;
 453         }
 454         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 455         xattr_ref->ea_size +=
 456             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 457         xattr_ref->dirty = true;
 458         return item;
 459 }
 460
 461 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 462                                   uint8_t name_index, const char *name,
 463                                   size_t name_len)
 464 {
 465         int ret = ENOENT;
 466         struct ext4_xattr_item *item =
 467             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 468         if (item) {
 469                 if (item == xattr_ref->iter_from)
 470                         xattr_ref->iter_from =
 471                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 472
 473                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 474                                       EXT4_XATTR_LEN(item->name_len);
 475
 476                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 477                 ext4_xattr_item_free(item);
 478                 xattr_ref->dirty = true;
 479                 ret = EOK;
 480         }
 481         return ret;
 482 }
 483
 484 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 485                                   struct ext4_xattr_item *item,
 486                                   size_t new_data_size)
 487 {
 488         int ret = EOK;
 489         size_t old_data_size = item->data_size;
 490         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 491                 EXT4_XATTR_SIZE(new_data_size)
 492                         >
 493             ext4_xattr_inode_space(xattr_ref) -
 494                 sizeof(struct ext4_xattr_ibody_header))
 495                 &&
 496             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 497                 EXT4_XATTR_SIZE(new_data_size)
 498                         >
 499             ext4_xattr_block_space(xattr_ref) -
 500                 sizeof(struct ext4_xattr_header))) {
 501
 502                 return ENOSPC;
 503         }
 504         ret = ext4_xattr_item_resize_data(item, new_data_size);
 505         if (ret != EOK) {
 506                 return ret;
 507         }
 508         xattr_ref->ea_size =
 509             xattr_ref->ea_size -
 510             EXT4_XATTR_SIZE(old_data_size) +
 511             EXT4_XATTR_SIZE(new_data_size);
 512         xattr_ref->dirty = true;
 513         return ret;
 514 }
 515
 516 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 517 {
 518         struct ext4_xattr_item *item, *save_item;
 519         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 520         {
 521                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 522                 ext4_xattr_item_free(item);
 523         }
 524         xattr_ref->ea_size = 0;
 525 }
 526
 527 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 528 {
 529         int ret = EOK;
 530
 531         ext4_fsblk_t xattr_block = 0;
 532         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 533                                               &xattr_ref->fs->sb);
 534         if (!xattr_block) {
 535                 ext4_fsblk_t goal =
 536                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 537
 538                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 539                                               goal,
 540                                               &xattr_block);
 541                 if (ret != EOK)
 542                         goto Finish;
 543
 544                 ret = ext4_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 545                                      xattr_block);
 546                 if (ret != EOK) {
 547                         ext4_balloc_free_block(xattr_ref->inode_ref,
 548                                                xattr_block);
 549                         goto Finish;
 550                 }
 551
 552                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 553                                         &xattr_ref->fs->sb, xattr_block);
 554                 xattr_ref->inode_ref->dirty = true;
 555                 xattr_ref->block_loaded = true;
 556         }
 557
 558 Finish:
 559         return ret;
 560 }
 561
 562 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 563 {
 564         ext4_fsblk_t xattr_block;
 565         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 566                                               &xattr_ref->fs->sb);
 567         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 568                                 0);
 569         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 570         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 571         xattr_ref->inode_ref->dirty = true;
 572         xattr_ref->block_loaded = false;
 573 }
 574
 575 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 576 {
 577         struct ext4_xattr_header *block_header = NULL;
 578         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 579
 580         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 581         block_header->h_magic = EXT4_XATTR_MAGIC;
 582         block_header->h_refcount = to_le32(1);
 583         block_header->h_blocks = to_le32(1);
 584 }
 585
 586 static void
 587 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 588                            struct ext4_xattr_ibody_header *ibody_header,
 589                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 590 {
 591         entry->e_name_len = to_le32(item->name_len);
 592         entry->e_name_index = item->name_index;
 593         entry->e_value_offs =
 594             (char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header);
 595         entry->e_value_block = 0;
 596         entry->e_value_size = item->data_size;
 597 }
 598
 599 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 600                                        struct ext4_xattr_header *block_header,
 601                                        struct ext4_xattr_entry *block_entry,
 602                                        void *block_data_ptr)
 603 {
 604         block_entry->e_name_len = to_le32(item->name_len);
 605         block_entry->e_name_index = item->name_index;
 606         block_entry->e_value_offs =
 607             (char *)block_data_ptr - (char *)block_header;
 608         block_entry->e_value_block = 0;
 609         block_entry->e_value_size = item->data_size;
 610 }
 611
 612 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 613 {
 614         int ret = EOK;
 615         bool block_modified = false;
 616         void *ibody_data = NULL;
 617         void *block_data = NULL;
 618         struct ext4_xattr_item *item, *save_item;
 619         size_t inode_size_rem, block_size_rem;
 620         struct ext4_xattr_ibody_header *ibody_header = NULL;
 621         struct ext4_xattr_header *block_header = NULL;
 622         struct ext4_xattr_entry *entry = NULL;
 623         struct ext4_xattr_entry *block_entry = NULL;
 624
 625         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 626         block_size_rem = ext4_xattr_block_space(xattr_ref);
 627         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 628                 ibody_header = EXT4_XATTR_IHDR(xattr_ref->inode_ref->inode);
 629                 entry = EXT4_XATTR_IFIRST(ibody_header);
 630         }
 631
 632         if (!xattr_ref->dirty)
 633                 goto Finish;
 634         /* If there are enough spaces in the ibody EA table.*/
 635         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 636                 memset(ibody_header, 0, inode_size_rem);
 637                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 638                 ibody_data = (char *)ibody_header + inode_size_rem;
 639                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 640
 641                 xattr_ref->inode_ref->dirty = true;
 642         }
 643         /* If we need an extra block to hold the EA entries*/
 644         if (xattr_ref->ea_size > inode_size_rem) {
 645                 if (!xattr_ref->block_loaded) {
 646                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 647                         if (ret != EOK)
 648                                 goto Finish;
 649                 }
 650                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 651                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 652                 ext4_xattr_set_block_header(xattr_ref);
 653                 block_data = (char *)block_header + block_size_rem;
 654                 block_size_rem -= sizeof(struct ext4_xattr_header);
 655
 656                 xattr_ref->block.dirty = true;
 657         } else {
 658                 /* We don't need an extra block.*/
 659                 if (xattr_ref->block_loaded) {
 660                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 661                         block_header->h_refcount =
 662                             to_le32(to_le32(block_header->h_refcount) - 1);
 663                         if (!block_header->h_refcount) {
 664                                 ext4_xattr_try_free_block(xattr_ref);
 665                                 block_header = NULL;
 666                         } else {
 667                                 block_entry =
 668                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 669                                 block_data =
 670                                     (char *)block_header + block_size_rem;
 671                                 block_size_rem -=
 672                                     sizeof(struct ext4_xattr_header);
 673                                 ext4_inode_set_file_acl(
 674                                     xattr_ref->inode_ref->inode,
 675                                     &xattr_ref->fs->sb, 0);
 676
 677                                 xattr_ref->inode_ref->dirty = true;
 678                                 xattr_ref->block.dirty = true;
 679                         }
 680                 }
 681         }
 682         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 683         {
 684                 if (EXT4_XATTR_SIZE(item->data_size) +
 685                         EXT4_XATTR_LEN(item->name_len) <=
 686                     inode_size_rem) {
 687                         ibody_data = (char *)ibody_data -
 688                                      EXT4_XATTR_SIZE(item->data_size);
 689                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 690                                                    ibody_data);
 691                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 692                                item->name_len);
 693                         memcpy(ibody_data, item->data, item->data_size);
 694                         entry = EXT4_XATTR_NEXT(entry);
 695                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 696                                           EXT4_XATTR_LEN(item->name_len);
 697
 698                         xattr_ref->inode_ref->dirty = true;
 699                         continue;
 700                 }
 701                 if (EXT4_XATTR_SIZE(item->data_size) +
 702                         EXT4_XATTR_LEN(item->name_len) >
 703                     block_size_rem) {
 704                         ret = ENOSPC;
 705                         goto Finish;
 706                 }
 707                 block_data =
 708                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 709                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 710                                            block_data);
 711                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 712                        item->name_len);
 713                 memcpy(block_data, item->data, item->data_size);
 714                 block_entry = EXT4_XATTR_NEXT(block_entry);
 715                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 716                                   EXT4_XATTR_LEN(item->name_len);
 717
 718                 block_modified = true;
 719         }
 720         xattr_ref->dirty = false;
 721         if (block_modified) {
 722                 ext4_xattr_rehash(block_header,
 723                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 724                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 725                                               xattr_ref->block.lb_id,
 726                                               block_header);
 727                 xattr_ref->block.dirty = true;
 728         }
 729
 730 Finish:
 731         return ret;
 732 }
 733
 734 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 735                            int (*iter)(struct ext4_xattr_ref *ref,
 736                                      struct ext4_xattr_item *item))
 737 {
 738         struct ext4_xattr_item *item;
 739         if (!ref->iter_from)
 740                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 741
 742         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 743         {
 744                 int ret = EXT4_XATTR_ITERATE_CONT;
 745                 if (iter)
 746                         iter(ref, item);
 747
 748                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 749                         if (ret == EXT4_XATTR_ITERATE_STOP)
 750                                 ref->iter_from = NULL;
 751
 752                         break;
 753                 }
 754         }
 755 }
 756
 757 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 758 {
 759         ref->iter_from = NULL;
 760 }
 761
 762 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 763                       const char *name, size_t name_len, const void *data,
 764                       size_t data_size, bool replace)
 765 {
 766         int ret = EOK;
 767         struct ext4_xattr_item *item =
 768             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 769         if (replace) {
 770                 if (!item) {
 771                         ret = ENODATA;
 772                         goto Finish;
 773                 }
 774                 if (item->data_size != data_size)
 775                         ret = ext4_xattr_resize_item(ref, item, data_size);
 776
 777                 if (ret != EOK) {
 778                         goto Finish;
 779                 }
 780                 memcpy(item->data, data, data_size);
 781         } else {
 782                 if (item) {
 783                         ret = EEXIST;
 784                         goto Finish;
 785                 }
 786                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 787                                               data, data_size);
 788                 if (!item)
 789                         ret = ENOMEM;
 790         }
 791 Finish:
 792         return ret;
 793 }
 794
 795 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 796                          const char *name, size_t name_len)
 797 {
 798         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 799 }
 800
 801 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 802                       const char *name, size_t name_len, void *buf, size_t buf_size,
 803                       size_t *data_size)
 804 {
 805         int ret = EOK;
 806         size_t item_size = 0;
 807         struct ext4_xattr_item *item =
 808             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 809
 810         if (!item) {
 811                 ret = ENODATA;
 812                 goto Finish;
 813         }
 814         item_size = item->data_size;
 815         if (buf_size > item_size)
 816                 buf_size = item_size;
 817
 818         if (buf)
 819                 memcpy(buf, item->data, buf_size);
 820
 821 Finish:
 822         if (data_size)
 823                 *data_size = item_size;
 824
 825         return ret;
 826 }
 827
 828 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 829                           struct ext4_xattr_ref *ref)
 830 {
 831         int rc;
 832         ext4_fsblk_t xattr_block;
 833         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 834         RB_INIT(&ref->root);
 835         ref->ea_size = 0;
 836         ref->iter_from = NULL;
 837         if (xattr_block) {
 838                 rc = ext4_block_get(fs->bdev, &ref->block, xattr_block);
 839                 if (rc != EOK)
 840                         return EIO;
 841
 842                 ref->block_loaded = true;
 843         } else
 844                 ref->block_loaded = false;
 845
 846         ref->inode_ref = inode_ref;
 847         ref->fs = fs;
 848
 849         rc = ext4_xattr_fetch(ref);
 850         if (rc != EOK) {
 851                 ext4_xattr_purge_items(ref);
 852                 if (xattr_block)
 853                         ext4_block_set(fs->bdev, &inode_ref->block);
 854
 855                 ref->block_loaded = false;
 856                 return rc;
 857         }
 858         return EOK;
 859 }
 860
 861 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 862 {
 863         ext4_xattr_write_to_disk(ref);
 864         if (ref->block_loaded) {
 865                 ext4_block_set(ref->fs->bdev, &ref->block);
 866                 ref->block_loaded = false;
 867         }
 868         ext4_xattr_purge_items(ref);
 869         ref->inode_ref = NULL;
 870         ref->fs = NULL;
 871 }
 872
 873 struct xattr_prefix {
 874         const char *prefix;
 875         uint8_t name_index;
 876 };
 877
 878 static const struct xattr_prefix prefix_tbl[] = {
 879     {"user.", EXT4_XATTR_INDEX_USER},
 880     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 881     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 882     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 883     {NULL, 0},
 884 };
 885
 886 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 887                               uint8_t *name_index, size_t *name_len)
 888 {
 889         int i;
 890         ext4_assert(name_index);
 891         if (!full_name_len) {
 892                 if (name_len)
 893                         *name_len = 0;
 894
 895                 return NULL;
 896         }
 897
 898         for (i = 0; prefix_tbl[i].prefix; i++) {
 899                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 900                 if (full_name_len >= prefix_len &&
 901                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 902                         *name_index = prefix_tbl[i].name_index;
 903                         if (name_len)
 904                                 *name_len = full_name_len - prefix_len;
 905
 906                         return full_name + prefix_len;
 907                 }
 908         }
 909         if (name_len)
 910                 *name_len = 0;
 911
 912         return NULL;
 913 }
 914
 915 const char *ext4_get_xattr_name_prefix(uint8_t name_index, size_t *ret_prefix_len)
 916 {
 917         int i;
 918
 919         for (i = 0; prefix_tbl[i].prefix; i++) {
 920                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 921                 if (prefix_tbl[i].name_index == name_index) {
 922                         if (ret_prefix_len)
 923                                 *ret_prefix_len = prefix_len;
 924
 925                         return prefix_tbl[i].prefix;
 926                 }
 927         }
 928         if (ret_prefix_len)
 929                 *ret_prefix_len = 0;
 930
 931         return NULL;
 932 }
 933
 934 /**
 935  * @}
 936  */