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