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->fs->sb,
 276                                 xattr_ref->inode_ref->inode);
 277                 first_entry = EXT4_XATTR_IFIRST(header);
 278
 279                 ret = ((char *)first_entry + to_le16(entry->e_value_offs));
 280                 if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 281                         (char *)xattr_ref->inode_ref->inode > inode_size)
 282                         ret = NULL;
 283
 284                 return ret;
 285
 286         }
 287         int32_t block_size = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 288         ret = ((char *)xattr_ref->block.data + to_le16(entry->e_value_offs));
 289         if (ret + EXT4_XATTR_SIZE(to_le32(entry->e_value_size)) -
 290                         (char *)xattr_ref->block.data > block_size)
 291                 ret = NULL;
 292         return ret;
 293 }
 294
 295 static int ext4_xattr_block_fetch(struct ext4_xattr_ref *xattr_ref)
 296 {
 297         int ret = EOK;
 298         size_t size_rem;
 299         void *data;
 300         struct ext4_xattr_entry *entry = NULL;
 301
 302         ext4_assert(xattr_ref->block.data);
 303         entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 304
 305         size_rem = ext4_sb_get_block_size(&xattr_ref->fs->sb);
 306         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 307              entry = EXT4_XATTR_NEXT(entry),
 308              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 309                 struct ext4_xattr_item *item;
 310                 char *e_name = EXT4_XATTR_NAME(entry);
 311
 312                 data = ext4_xattr_entry_data(xattr_ref, entry, false);
 313                 if (!data) {
 314                         ret = EIO;
 315                         goto Finish;
 316                 }
 317
 318                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 319                                              (size_t)entry->e_name_len);
 320                 if (!item) {
 321                         ret = ENOMEM;
 322                         goto Finish;
 323                 }
 324                 if (ext4_xattr_item_alloc_data(
 325                         item, data, to_le32(entry->e_value_size)) != EOK) {
 326                         ext4_xattr_item_free(item);
 327                         ret = ENOMEM;
 328                         goto Finish;
 329                 }
 330                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 331                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 332                                       EXT4_XATTR_LEN(item->name_len);
 333         }
 334
 335 Finish:
 336         return ret;
 337 }
 338
 339 static int ext4_xattr_inode_fetch(struct ext4_xattr_ref *xattr_ref)
 340 {
 341         void *data;
 342         size_t size_rem;
 343         int ret = EOK;
 344         struct ext4_xattr_ibody_header *header = NULL;
 345         struct ext4_xattr_entry *entry = NULL;
 346         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 347         uint16_t extra_isize = ext4_inode_get_extra_isize(&xattr_ref->fs->sb,
 348                                         xattr_ref->inode_ref->inode);
 349
 350         header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 351                                  xattr_ref->inode_ref->inode);
 352         entry = EXT4_XATTR_IFIRST(header);
 353
 354         size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 355                    extra_isize;
 356         for (; size_rem > 0 && !EXT4_XATTR_IS_LAST_ENTRY(entry);
 357              entry = EXT4_XATTR_NEXT(entry),
 358              size_rem -= EXT4_XATTR_LEN(entry->e_name_len)) {
 359                 struct ext4_xattr_item *item;
 360                 char *e_name = EXT4_XATTR_NAME(entry);
 361
 362                 data = ext4_xattr_entry_data(xattr_ref, entry, true);
 363                 if (!data) {
 364                         ret = EIO;
 365                         goto Finish;
 366                 }
 367
 368                 item = ext4_xattr_item_alloc(entry->e_name_index, e_name,
 369                                              (size_t)entry->e_name_len);
 370                 if (!item) {
 371                         ret = ENOMEM;
 372                         goto Finish;
 373                 }
 374                 if (ext4_xattr_item_alloc_data(
 375                         item, data, to_le32(entry->e_value_size)) != EOK) {
 376                         ext4_xattr_item_free(item);
 377                         ret = ENOMEM;
 378                         goto Finish;
 379                 }
 380                 RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 381                 xattr_ref->ea_size += EXT4_XATTR_SIZE(item->data_size) +
 382                                       EXT4_XATTR_LEN(item->name_len);
 383         }
 384
 385 Finish:
 386         return ret;
 387 }
 388
 389 static size_t ext4_xattr_inode_space(struct ext4_xattr_ref *xattr_ref)
 390 {
 391         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 392         uint16_t extra_isize = ext4_inode_get_extra_isize(&xattr_ref->fs->sb,
 393                                         xattr_ref->inode_ref->inode);
 394         uint16_t size_rem = inode_size - EXT4_GOOD_OLD_INODE_SIZE -
 395                             extra_isize;
 396         return size_rem;
 397 }
 398
 399 static size_t ext4_xattr_block_space(struct ext4_xattr_ref *xattr_ref)
 400 {
 401         return ext4_sb_get_block_size(&xattr_ref->fs->sb);
 402 }
 403
 404 static int ext4_xattr_fetch(struct ext4_xattr_ref *xattr_ref)
 405 {
 406         int ret = EOK;
 407         uint16_t inode_size = ext4_get16(&xattr_ref->fs->sb, inode_size);
 408         if (inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
 409                 ret = ext4_xattr_inode_fetch(xattr_ref);
 410                 if (ret != EOK)
 411                         return ret;
 412         }
 413
 414         if (xattr_ref->block_loaded)
 415                 ret = ext4_xattr_block_fetch(xattr_ref);
 416
 417         xattr_ref->dirty = false;
 418         return ret;
 419 }
 420
 421 static struct ext4_xattr_item *
 422 ext4_xattr_lookup_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 423                        const char *name, size_t name_len)
 424 {
 425         struct ext4_xattr_item tmp = {
 426                 .name_index = name_index,
 427                 .name = (char *)name, /*RB_FIND - won't touch this string*/
 428                 .name_len = name_len,
 429         };
 430         if (name_index == EXT4_XATTR_INDEX_SYSTEM &&
 431             name_len == 4 &&
 432             !memcmp(name, "data", 4))
 433                 tmp.in_inode = true;
 434
 435         return RB_FIND(ext4_xattr_tree, &xattr_ref->root, &tmp);
 436 }
 437
 438 static struct ext4_xattr_item *
 439 ext4_xattr_insert_item(struct ext4_xattr_ref *xattr_ref, uint8_t name_index,
 440                        const char *name, size_t name_len, const void *data,
 441                        size_t data_size)
 442 {
 443         struct ext4_xattr_item *item;
 444         item = ext4_xattr_item_alloc(name_index, name, name_len);
 445         if (!item)
 446                 return NULL;
 447
 448         if ((xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 449                 EXT4_XATTR_LEN(item->name_len)
 450                         >
 451             ext4_xattr_inode_space(xattr_ref) -
 452                 sizeof(struct ext4_xattr_ibody_header))
 453                 &&
 454             (xattr_ref->ea_size + EXT4_XATTR_SIZE(data_size) +
 455                 EXT4_XATTR_LEN(item->name_len) >
 456             ext4_xattr_block_space(xattr_ref) -
 457                 sizeof(struct ext4_xattr_header))) {
 458                 ext4_xattr_item_free(item);
 459
 460                 return NULL;
 461         }
 462         if (ext4_xattr_item_alloc_data(item, data, data_size) != EOK) {
 463                 ext4_xattr_item_free(item);
 464                 return NULL;
 465         }
 466         RB_INSERT(ext4_xattr_tree, &xattr_ref->root, item);
 467         xattr_ref->ea_size +=
 468             EXT4_XATTR_SIZE(item->data_size) + EXT4_XATTR_LEN(item->name_len);
 469         xattr_ref->dirty = true;
 470         return item;
 471 }
 472
 473 static int ext4_xattr_remove_item(struct ext4_xattr_ref *xattr_ref,
 474                                   uint8_t name_index, const char *name,
 475                                   size_t name_len)
 476 {
 477         int ret = ENOENT;
 478         struct ext4_xattr_item *item =
 479             ext4_xattr_lookup_item(xattr_ref, name_index, name, name_len);
 480         if (item) {
 481                 if (item == xattr_ref->iter_from)
 482                         xattr_ref->iter_from =
 483                             RB_NEXT(ext4_xattr_tree, &xattr_ref->root, item);
 484
 485                 xattr_ref->ea_size -= EXT4_XATTR_SIZE(item->data_size) +
 486                                       EXT4_XATTR_LEN(item->name_len);
 487
 488                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 489                 ext4_xattr_item_free(item);
 490                 xattr_ref->dirty = true;
 491                 ret = EOK;
 492         }
 493         return ret;
 494 }
 495
 496 static int ext4_xattr_resize_item(struct ext4_xattr_ref *xattr_ref,
 497                                   struct ext4_xattr_item *item,
 498                                   size_t new_data_size)
 499 {
 500         int ret = EOK;
 501         size_t old_data_size = item->data_size;
 502         if ((xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 503                 EXT4_XATTR_SIZE(new_data_size)
 504                         >
 505             ext4_xattr_inode_space(xattr_ref) -
 506                 sizeof(struct ext4_xattr_ibody_header))
 507                 &&
 508             (xattr_ref->ea_size - EXT4_XATTR_SIZE(old_data_size) +
 509                 EXT4_XATTR_SIZE(new_data_size)
 510                         >
 511             ext4_xattr_block_space(xattr_ref) -
 512                 sizeof(struct ext4_xattr_header))) {
 513
 514                 return ENOSPC;
 515         }
 516         ret = ext4_xattr_item_resize_data(item, new_data_size);
 517         if (ret != EOK) {
 518                 return ret;
 519         }
 520         xattr_ref->ea_size =
 521             xattr_ref->ea_size -
 522             EXT4_XATTR_SIZE(old_data_size) +
 523             EXT4_XATTR_SIZE(new_data_size);
 524         xattr_ref->dirty = true;
 525         return ret;
 526 }
 527
 528 static void ext4_xattr_purge_items(struct ext4_xattr_ref *xattr_ref)
 529 {
 530         struct ext4_xattr_item *item, *save_item;
 531         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 532         {
 533                 RB_REMOVE(ext4_xattr_tree, &xattr_ref->root, item);
 534                 ext4_xattr_item_free(item);
 535         }
 536         xattr_ref->ea_size = 0;
 537 }
 538
 539 static int ext4_xattr_try_alloc_block(struct ext4_xattr_ref *xattr_ref)
 540 {
 541         int ret = EOK;
 542
 543         ext4_fsblk_t xattr_block = 0;
 544         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 545                                               &xattr_ref->fs->sb);
 546         if (!xattr_block) {
 547                 ext4_fsblk_t goal =
 548                         ext4_fs_inode_to_goal_block(xattr_ref->inode_ref);
 549
 550                 ret = ext4_balloc_alloc_block(xattr_ref->inode_ref,
 551                                               goal,
 552                                               &xattr_block);
 553                 if (ret != EOK)
 554                         goto Finish;
 555
 556                 ret = ext4_trans_block_get(xattr_ref->fs->bdev, &xattr_ref->block,
 557                                      xattr_block);
 558                 if (ret != EOK) {
 559                         ext4_balloc_free_block(xattr_ref->inode_ref,
 560                                                xattr_block);
 561                         goto Finish;
 562                 }
 563
 564                 ext4_inode_set_file_acl(xattr_ref->inode_ref->inode,
 565                                         &xattr_ref->fs->sb, xattr_block);
 566                 xattr_ref->inode_ref->dirty = true;
 567                 xattr_ref->block_loaded = true;
 568         }
 569
 570 Finish:
 571         return ret;
 572 }
 573
 574 static void ext4_xattr_try_free_block(struct ext4_xattr_ref *xattr_ref)
 575 {
 576         ext4_fsblk_t xattr_block;
 577         xattr_block = ext4_inode_get_file_acl(xattr_ref->inode_ref->inode,
 578                                               &xattr_ref->fs->sb);
 579         ext4_inode_set_file_acl(xattr_ref->inode_ref->inode, &xattr_ref->fs->sb,
 580                                 0);
 581         ext4_block_set(xattr_ref->fs->bdev, &xattr_ref->block);
 582         ext4_balloc_free_block(xattr_ref->inode_ref, xattr_block);
 583         xattr_ref->inode_ref->dirty = true;
 584         xattr_ref->block_loaded = false;
 585 }
 586
 587 static void ext4_xattr_set_block_header(struct ext4_xattr_ref *xattr_ref)
 588 {
 589         struct ext4_xattr_header *block_header = NULL;
 590         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 591
 592         memset(block_header, 0, sizeof(struct ext4_xattr_header));
 593         block_header->h_magic = EXT4_XATTR_MAGIC;
 594         block_header->h_refcount = to_le32(1);
 595         block_header->h_blocks = to_le32(1);
 596 }
 597
 598 static void
 599 ext4_xattr_set_inode_entry(struct ext4_xattr_item *item,
 600                            struct ext4_xattr_ibody_header *ibody_header,
 601                            struct ext4_xattr_entry *entry, void *ibody_data_ptr)
 602 {
 603         entry->e_name_len = (uint8_t)item->name_len;
 604         entry->e_name_index = item->name_index;
 605         entry->e_value_offs =
 606             to_le16((char *)ibody_data_ptr - (char *)EXT4_XATTR_IFIRST(ibody_header));
 607         entry->e_value_block = 0;
 608         entry->e_value_size = to_le32(item->data_size);
 609 }
 610
 611 static void ext4_xattr_set_block_entry(struct ext4_xattr_item *item,
 612                                        struct ext4_xattr_header *block_header,
 613                                        struct ext4_xattr_entry *block_entry,
 614                                        void *block_data_ptr)
 615 {
 616         block_entry->e_name_len = (uint8_t)item->name_len;
 617         block_entry->e_name_index = item->name_index;
 618         block_entry->e_value_offs =
 619             to_le16((char *)block_data_ptr - (char *)block_header);
 620         block_entry->e_value_block = 0;
 621         block_entry->e_value_size = to_le32(item->data_size);
 622 }
 623
 624 static int ext4_xattr_write_to_disk(struct ext4_xattr_ref *xattr_ref)
 625 {
 626         int ret = EOK;
 627         bool block_modified = false;
 628         void *ibody_data = NULL;
 629         void *block_data = NULL;
 630         struct ext4_xattr_item *item, *save_item;
 631         size_t inode_size_rem, block_size_rem;
 632         struct ext4_xattr_ibody_header *ibody_header = NULL;
 633         struct ext4_xattr_header *block_header = NULL;
 634         struct ext4_xattr_entry *entry = NULL;
 635         struct ext4_xattr_entry *block_entry = NULL;
 636
 637         inode_size_rem = ext4_xattr_inode_space(xattr_ref);
 638         block_size_rem = ext4_xattr_block_space(xattr_ref);
 639         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 640                 ibody_header = EXT4_XATTR_IHDR(&xattr_ref->fs->sb,
 641                                                xattr_ref->inode_ref->inode);
 642                 entry = EXT4_XATTR_IFIRST(ibody_header);
 643         }
 644
 645         if (!xattr_ref->dirty)
 646                 goto Finish;
 647         /* If there are enough spaces in the ibody EA table.*/
 648         if (inode_size_rem > sizeof(struct ext4_xattr_ibody_header)) {
 649                 memset(ibody_header, 0, inode_size_rem);
 650                 ibody_header->h_magic = EXT4_XATTR_MAGIC;
 651                 ibody_data = (char *)ibody_header + inode_size_rem;
 652                 inode_size_rem -= sizeof(struct ext4_xattr_ibody_header);
 653
 654                 xattr_ref->inode_ref->dirty = true;
 655         }
 656         /* If we need an extra block to hold the EA entries*/
 657         if (xattr_ref->ea_size > inode_size_rem) {
 658                 if (!xattr_ref->block_loaded) {
 659                         ret = ext4_xattr_try_alloc_block(xattr_ref);
 660                         if (ret != EOK)
 661                                 goto Finish;
 662                 }
 663                 block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 664                 block_entry = EXT4_XATTR_BFIRST(&xattr_ref->block);
 665                 ext4_xattr_set_block_header(xattr_ref);
 666                 block_data = (char *)block_header + block_size_rem;
 667                 block_size_rem -= sizeof(struct ext4_xattr_header);
 668
 669                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 670         } else {
 671                 /* We don't need an extra block.*/
 672                 if (xattr_ref->block_loaded) {
 673                         block_header = EXT4_XATTR_BHDR(&xattr_ref->block);
 674                         block_header->h_refcount =
 675                             to_le32(to_le32(block_header->h_refcount) - 1);
 676                         if (!block_header->h_refcount) {
 677                                 ext4_xattr_try_free_block(xattr_ref);
 678                                 block_header = NULL;
 679                         } else {
 680                                 block_entry =
 681                                     EXT4_XATTR_BFIRST(&xattr_ref->block);
 682                                 block_data =
 683                                     (char *)block_header + block_size_rem;
 684                                 block_size_rem -=
 685                                     sizeof(struct ext4_xattr_header);
 686                                 ext4_inode_set_file_acl(
 687                                     xattr_ref->inode_ref->inode,
 688                                     &xattr_ref->fs->sb, 0);
 689
 690                                 xattr_ref->inode_ref->dirty = true;
 691                                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 692                         }
 693                 }
 694         }
 695         RB_FOREACH_SAFE(item, ext4_xattr_tree, &xattr_ref->root, save_item)
 696         {
 697                 if (EXT4_XATTR_SIZE(item->data_size) +
 698                         EXT4_XATTR_LEN(item->name_len) <=
 699                     inode_size_rem) {
 700                         ibody_data = (char *)ibody_data -
 701                                      EXT4_XATTR_SIZE(item->data_size);
 702                         ext4_xattr_set_inode_entry(item, ibody_header, entry,
 703                                                    ibody_data);
 704                         memcpy(EXT4_XATTR_NAME(entry), item->name,
 705                                item->name_len);
 706                         memcpy(ibody_data, item->data, item->data_size);
 707                         entry = EXT4_XATTR_NEXT(entry);
 708                         inode_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 709                                           EXT4_XATTR_LEN(item->name_len);
 710
 711                         xattr_ref->inode_ref->dirty = true;
 712                         continue;
 713                 }
 714                 if (EXT4_XATTR_SIZE(item->data_size) +
 715                         EXT4_XATTR_LEN(item->name_len) >
 716                     block_size_rem) {
 717                         ret = ENOSPC;
 718                         goto Finish;
 719                 }
 720                 block_data =
 721                     (char *)block_data - EXT4_XATTR_SIZE(item->data_size);
 722                 ext4_xattr_set_block_entry(item, block_header, block_entry,
 723                                            block_data);
 724                 memcpy(EXT4_XATTR_NAME(block_entry), item->name,
 725                        item->name_len);
 726                 memcpy(block_data, item->data, item->data_size);
 727                 block_entry = EXT4_XATTR_NEXT(block_entry);
 728                 block_size_rem -= EXT4_XATTR_SIZE(item->data_size) +
 729                                   EXT4_XATTR_LEN(item->name_len);
 730
 731                 block_modified = true;
 732         }
 733         xattr_ref->dirty = false;
 734         if (block_modified) {
 735                 ext4_xattr_rehash(block_header,
 736                                   EXT4_XATTR_BFIRST(&xattr_ref->block));
 737                 ext4_xattr_set_block_checksum(xattr_ref->inode_ref,
 738                                               xattr_ref->block.lb_id,
 739                                               block_header);
 740                 ext4_trans_set_block_dirty(xattr_ref->block.buf);
 741         }
 742
 743 Finish:
 744         return ret;
 745 }
 746
 747 void ext4_fs_xattr_iterate(struct ext4_xattr_ref *ref,
 748                            int (*iter)(struct ext4_xattr_ref *ref,
 749                                      struct ext4_xattr_item *item))
 750 {
 751         struct ext4_xattr_item *item;
 752         if (!ref->iter_from)
 753                 ref->iter_from = RB_MIN(ext4_xattr_tree, &ref->root);
 754
 755         RB_FOREACH_FROM(item, ext4_xattr_tree, ref->iter_from)
 756         {
 757                 int ret = EXT4_XATTR_ITERATE_CONT;
 758                 if (iter)
 759                         iter(ref, item);
 760
 761                 if (ret != EXT4_XATTR_ITERATE_CONT) {
 762                         if (ret == EXT4_XATTR_ITERATE_STOP)
 763                                 ref->iter_from = NULL;
 764
 765                         break;
 766                 }
 767         }
 768 }
 769
 770 void ext4_fs_xattr_iterate_reset(struct ext4_xattr_ref *ref)
 771 {
 772         ref->iter_from = NULL;
 773 }
 774
 775 int ext4_fs_set_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 776                       const char *name, size_t name_len, const void *data,
 777                       size_t data_size, bool replace)
 778 {
 779         int ret = EOK;
 780         struct ext4_xattr_item *item =
 781             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 782         if (replace) {
 783                 if (!item) {
 784                         ret = ENODATA;
 785                         goto Finish;
 786                 }
 787                 if (item->data_size != data_size)
 788                         ret = ext4_xattr_resize_item(ref, item, data_size);
 789
 790                 if (ret != EOK) {
 791                         goto Finish;
 792                 }
 793                 memcpy(item->data, data, data_size);
 794         } else {
 795                 if (item) {
 796                         ret = EEXIST;
 797                         goto Finish;
 798                 }
 799                 item = ext4_xattr_insert_item(ref, name_index, name, name_len,
 800                                               data, data_size);
 801                 if (!item)
 802                         ret = ENOMEM;
 803         }
 804 Finish:
 805         return ret;
 806 }
 807
 808 int ext4_fs_remove_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 809                          const char *name, size_t name_len)
 810 {
 811         return ext4_xattr_remove_item(ref, name_index, name, name_len);
 812 }
 813
 814 int ext4_fs_get_xattr(struct ext4_xattr_ref *ref, uint8_t name_index,
 815                       const char *name, size_t name_len, void *buf,
 816                       size_t buf_size, size_t *data_size)
 817 {
 818         int ret = EOK;
 819         size_t item_size = 0;
 820         struct ext4_xattr_item *item =
 821             ext4_xattr_lookup_item(ref, name_index, name, name_len);
 822
 823         if (!item) {
 824                 ret = ENODATA;
 825                 goto Finish;
 826         }
 827         item_size = item->data_size;
 828         if (buf_size > item_size)
 829                 buf_size = item_size;
 830
 831         if (buf)
 832                 memcpy(buf, item->data, buf_size);
 833
 834 Finish:
 835         if (data_size)
 836                 *data_size = item_size;
 837
 838         return ret;
 839 }
 840
 841 int ext4_fs_get_xattr_ref(struct ext4_fs *fs, struct ext4_inode_ref *inode_ref,
 842                           struct ext4_xattr_ref *ref)
 843 {
 844         int rc;
 845         ext4_fsblk_t xattr_block;
 846         xattr_block = ext4_inode_get_file_acl(inode_ref->inode, &fs->sb);
 847         RB_INIT(&ref->root);
 848         ref->ea_size = 0;
 849         ref->iter_from = NULL;
 850         if (xattr_block) {
 851                 rc = ext4_trans_block_get(fs->bdev, &ref->block, xattr_block);
 852                 if (rc != EOK)
 853                         return EIO;
 854
 855                 ref->block_loaded = true;
 856         } else
 857                 ref->block_loaded = false;
 858
 859         ref->inode_ref = inode_ref;
 860         ref->fs = fs;
 861
 862         rc = ext4_xattr_fetch(ref);
 863         if (rc != EOK) {
 864                 ext4_xattr_purge_items(ref);
 865                 if (xattr_block)
 866                         ext4_block_set(fs->bdev, &ref->block);
 867
 868                 ref->block_loaded = false;
 869                 return rc;
 870         }
 871         return EOK;
 872 }
 873
 874 void ext4_fs_put_xattr_ref(struct ext4_xattr_ref *ref)
 875 {
 876         ext4_xattr_write_to_disk(ref);
 877         if (ref->block_loaded) {
 878                 ext4_block_set(ref->fs->bdev, &ref->block);
 879                 ref->block_loaded = false;
 880         }
 881         ext4_xattr_purge_items(ref);
 882         ref->inode_ref = NULL;
 883         ref->fs = NULL;
 884 }
 885
 886 struct xattr_prefix {
 887         const char *prefix;
 888         uint8_t name_index;
 889 };
 890
 891 static const struct xattr_prefix prefix_tbl[] = {
 892     {"user.", EXT4_XATTR_INDEX_USER},
 893     {"system.posix_acl_access", EXT4_XATTR_INDEX_POSIX_ACL_ACCESS},
 894     {"system.posix_acl_default", EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT},
 895     {"trusted.", EXT4_XATTR_INDEX_TRUSTED},
 896     {"security.", EXT4_XATTR_INDEX_SECURITY},
 897     {"system.", EXT4_XATTR_INDEX_SYSTEM},
 898     {"system.richacl", EXT4_XATTR_INDEX_RICHACL},
 899     {NULL, 0},
 900 };
 901
 902 const char *ext4_extract_xattr_name(const char *full_name, size_t full_name_len,
 903                               uint8_t *name_index, size_t *name_len,
 904                               bool *found)
 905 {
 906         int i;
 907         ext4_assert(name_index);
 908         ext4_assert(found);
 909
 910         *found = false;
 911
 912         if (!full_name_len) {
 913                 if (name_len)
 914                         *name_len = 0;
 915
 916                 return NULL;
 917         }
 918
 919         for (i = 0; prefix_tbl[i].prefix; i++) {
 920                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 921                 if (full_name_len >= prefix_len &&
 922                     !memcmp(full_name, prefix_tbl[i].prefix, prefix_len)) {
 923                         bool require_name =
 924                                 prefix_tbl[i].prefix[prefix_len - 1] == '.';
 925                         *name_index = prefix_tbl[i].name_index;
 926                         if (name_len)
 927                                 *name_len = full_name_len - prefix_len;
 928
 929                         if (!(full_name_len - prefix_len) && require_name)
 930                                 return NULL;
 931
 932                         *found = true;
 933                         if (require_name)
 934                                 return full_name + prefix_len;
 935
 936                         return NULL;
 937                 }
 938         }
 939         if (name_len)
 940                 *name_len = 0;
 941
 942         return NULL;
 943 }
 944
 945 const char *ext4_get_xattr_name_prefix(uint8_t name_index,
 946                                        size_t *ret_prefix_len)
 947 {
 948         int i;
 949
 950         for (i = 0; prefix_tbl[i].prefix; i++) {
 951                 size_t prefix_len = strlen(prefix_tbl[i].prefix);
 952                 if (prefix_tbl[i].name_index == name_index) {
 953                         if (ret_prefix_len)
 954                                 *ret_prefix_len = prefix_len;
 955
 956                         return prefix_tbl[i].prefix;
 957                 }
 958         }
 959         if (ret_prefix_len)
 960                 *ret_prefix_len = 0;
 961
 962         return NULL;
 963 }
 964
 965 /**
 966  * @}
 967  */