lib/ext2fs/ext_attr.c

   1 /*
   2  * ext_attr.c --- extended attribute blocks
   3  *
   4  * Copyright (C) 2001 Andreas Gruenbacher, <a.gruenbacher@computer.org>
   5  *
   6  * Copyright (C) 2002 Theodore Ts'o.
   7  *
   8  * %Begin-Header%
   9  * This file may be redistributed under the terms of the GNU Library
  10  * General Public License, version 2.
  11  * %End-Header%
  12  */
  13
  14 #include "config.h"
  15 #include <stdio.h>
  16 #if HAVE_UNISTD_H
  17 #include <unistd.h>
  18 #endif
  19 #include <string.h>
  20 #include <time.h>
  21
  22 #include "ext2_fs.h"
  23 #include "ext2_ext_attr.h"
  24
  25 #include "ext2fs.h"
  26
  27 #define NAME_HASH_SHIFT 5
  28 #define VALUE_HASH_SHIFT 16
  29
  30 /*
  31  * ext2_xattr_hash_entry()
  32  *
  33  * Compute the hash of an extended attribute.
  34  */
  35 __u32 ext2fs_ext_attr_hash_entry(struct ext2_ext_attr_entry *entry, void *data)
  36 {
  37         __u32 hash = 0;
  38         char *name = ((char *) entry) + sizeof(struct ext2_ext_attr_entry);
  39         int n;
  40
  41         for (n = 0; n < entry->e_name_len; n++) {
  42                 hash = (hash << NAME_HASH_SHIFT) ^
  43                        (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
  44                        *name++;
  45         }
  46
  47         /* The hash needs to be calculated on the data in little-endian. */
  48         if (entry->e_value_block == 0 && entry->e_value_size != 0) {
  49                 __u32 *value = (__u32 *)data;
  50                 for (n = (entry->e_value_size + EXT2_EXT_ATTR_ROUND) >>
  51                          EXT2_EXT_ATTR_PAD_BITS; n; n--) {
  52                         hash = (hash << VALUE_HASH_SHIFT) ^
  53                                (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^
  54                                ext2fs_le32_to_cpu(*value++);
  55                 }
  56         }
  57
  58         return hash;
  59 }
  60
  61 static errcode_t check_ext_attr_header(struct ext2_ext_attr_header *header)
  62 {
  63         if ((header->h_magic != EXT2_EXT_ATTR_MAGIC_v1 &&
  64              header->h_magic != EXT2_EXT_ATTR_MAGIC) ||
  65             header->h_blocks != 1)
  66                 return EXT2_ET_BAD_EA_HEADER;
  67
  68         return 0;
  69 }
  70
  71 #undef NAME_HASH_SHIFT
  72 #undef VALUE_HASH_SHIFT
  73
  74 errcode_t ext2fs_read_ext_attr3(ext2_filsys fs, blk64_t block, void *buf,
  75                                 ext2_ino_t inum)
  76 {
  77         int             csum_failed = 0;
  78         errcode_t       retval;
  79
  80         retval = io_channel_read_blk64(fs->io, block, 1, buf);
  81         if (retval)
  82                 return retval;
  83
  84         if (!(fs->flags & EXT2_FLAG_IGNORE_CSUM_ERRORS) &&
  85             !ext2fs_ext_attr_block_csum_verify(fs, inum, block, buf))
  86                 csum_failed = 1;
  87
  88 #ifdef WORDS_BIGENDIAN
  89         ext2fs_swap_ext_attr(buf, buf, fs->blocksize, 1);
  90 #endif
  91
  92         retval = check_ext_attr_header(buf);
  93         if (retval == 0 && csum_failed)
  94                 retval = EXT2_ET_EXT_ATTR_CSUM_INVALID;
  95
  96         return retval;
  97 }
  98
  99 errcode_t ext2fs_read_ext_attr2(ext2_filsys fs, blk64_t block, void *buf)
 100 {
 101         return ext2fs_read_ext_attr3(fs, block, buf, 0);
 102 }
 103
 104 errcode_t ext2fs_read_ext_attr(ext2_filsys fs, blk_t block, void *buf)
 105 {
 106         return ext2fs_read_ext_attr2(fs, block, buf);
 107 }
 108
 109 errcode_t ext2fs_write_ext_attr3(ext2_filsys fs, blk64_t block, void *inbuf,
 110                                  ext2_ino_t inum)
 111 {
 112         errcode_t       retval;
 113         char            *write_buf;
 114
 115 #ifdef WORDS_BIGENDIAN
 116         retval = ext2fs_get_mem(fs->blocksize, &write_buf);
 117         if (retval)
 118                 return retval;
 119         ext2fs_swap_ext_attr(write_buf, inbuf, fs->blocksize, 1);
 120 #else
 121         write_buf = (char *) inbuf;
 122 #endif
 123
 124         retval = ext2fs_ext_attr_block_csum_set(fs, inum, block,
 125                         (struct ext2_ext_attr_header *)write_buf);
 126         if (retval)
 127                 return retval;
 128
 129         retval = io_channel_write_blk64(fs->io, block, 1, write_buf);
 130 #ifdef WORDS_BIGENDIAN
 131         ext2fs_free_mem(&write_buf);
 132 #endif
 133         if (!retval)
 134                 ext2fs_mark_changed(fs);
 135         return retval;
 136 }
 137
 138 errcode_t ext2fs_write_ext_attr2(ext2_filsys fs, blk64_t block, void *inbuf)
 139 {
 140         return ext2fs_write_ext_attr3(fs, block, inbuf, 0);
 141 }
 142
 143 errcode_t ext2fs_write_ext_attr(ext2_filsys fs, blk_t block, void *inbuf)
 144 {
 145         return ext2fs_write_ext_attr2(fs, block, inbuf);
 146 }
 147
 148 /*
 149  * This function adjusts the reference count of the EA block.
 150  */
 151 errcode_t ext2fs_adjust_ea_refcount3(ext2_filsys fs, blk64_t blk,
 152                                     char *block_buf, int adjust,
 153                                     __u32 *newcount, ext2_ino_t inum)
 154 {
 155         errcode_t       retval;
 156         struct ext2_ext_attr_header *header;
 157         char    *buf = 0;
 158
 159         if ((blk >= ext2fs_blocks_count(fs->super)) ||
 160             (blk < fs->super->s_first_data_block))
 161                 return EXT2_ET_BAD_EA_BLOCK_NUM;
 162
 163         if (!block_buf) {
 164                 retval = ext2fs_get_mem(fs->blocksize, &buf);
 165                 if (retval)
 166                         return retval;
 167                 block_buf = buf;
 168         }
 169
 170         retval = ext2fs_read_ext_attr3(fs, blk, block_buf, inum);
 171         if (retval)
 172                 goto errout;
 173
 174         header = (struct ext2_ext_attr_header *) block_buf;
 175         header->h_refcount += adjust;
 176         if (newcount)
 177                 *newcount = header->h_refcount;
 178
 179         retval = ext2fs_write_ext_attr3(fs, blk, block_buf, inum);
 180         if (retval)
 181                 goto errout;
 182
 183 errout:
 184         if (buf)
 185                 ext2fs_free_mem(&buf);
 186         return retval;
 187 }
 188
 189 errcode_t ext2fs_adjust_ea_refcount2(ext2_filsys fs, blk64_t blk,
 190                                     char *block_buf, int adjust,
 191                                     __u32 *newcount)
 192 {
 193         return ext2fs_adjust_ea_refcount3(fs, blk, block_buf, adjust,
 194                                           newcount, 0);
 195 }
 196
 197 errcode_t ext2fs_adjust_ea_refcount(ext2_filsys fs, blk_t blk,
 198                                         char *block_buf, int adjust,
 199                                         __u32 *newcount)
 200 {
 201         return ext2fs_adjust_ea_refcount2(fs, blk, block_buf, adjust,
 202                                           newcount);
 203 }
 204
 205 /* Manipulate the contents of extended attribute regions */
 206 struct ext2_xattr {
 207         char *name;
 208         void *value;
 209         size_t value_len;
 210 };
 211
 212 struct ext2_xattr_handle {
 213         errcode_t magic;
 214         ext2_filsys fs;
 215         struct ext2_xattr *attrs;
 216         size_t length, count;
 217         ext2_ino_t ino;
 218         int dirty;
 219 };
 220
 221 static errcode_t ext2fs_xattrs_expand(struct ext2_xattr_handle *h,
 222                                       unsigned int expandby)
 223 {
 224         struct ext2_xattr *new_attrs;
 225         errcode_t err;
 226
 227         err = ext2fs_get_arrayzero(h->length + expandby,
 228                                    sizeof(struct ext2_xattr), &new_attrs);
 229         if (err)
 230                 return err;
 231
 232         memcpy(new_attrs, h->attrs, h->length * sizeof(struct ext2_xattr));
 233         ext2fs_free_mem(&h->attrs);
 234         h->length += expandby;
 235         h->attrs = new_attrs;
 236
 237         return 0;
 238 }
 239
 240 struct ea_name_index {
 241         int index;
 242         const char *name;
 243 };
 244
 245 /* Keep these names sorted in order of decreasing specificity. */
 246 static struct ea_name_index ea_names[] = {
 247         {3, "system.posix_acl_default"},
 248         {2, "system.posix_acl_access"},
 249         {8, "system.richacl"},
 250         {6, "security."},
 251         {4, "trusted."},
 252         {7, "system."},
 253         {1, "user."},
 254         {0, NULL},
 255 };
 256
 257 /* Push empty attributes to the end and inlinedata to the front. */
 258 static int attr_compare(const void *a, const void *b)
 259 {
 260         const struct ext2_xattr *xa = a, *xb = b;
 261
 262         if (xa->name == NULL)
 263                 return +1;
 264         else if (xb->name == NULL)
 265                 return -1;
 266         else if (!strcmp(xa->name, "system.data"))
 267                 return -1;
 268         else if (!strcmp(xb->name, "system.data"))
 269                 return +1;
 270         return 0;
 271 }
 272
 273 static const char *find_ea_prefix(int index)
 274 {
 275         struct ea_name_index *e;
 276
 277         for (e = ea_names; e->name; e++)
 278                 if (e->index == index)
 279                         return e->name;
 280
 281         return NULL;
 282 }
 283
 284 static int find_ea_index(const char *fullname, char **name, int *index)
 285 {
 286         struct ea_name_index *e;
 287
 288         for (e = ea_names; e->name; e++) {
 289                 if (memcmp(fullname, e->name, strlen(e->name)) == 0) {
 290                         *name = (char *)fullname + strlen(e->name);
 291                         *index = e->index;
 292                         return 1;
 293                 }
 294         }
 295         return 0;
 296 }
 297
 298 errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
 299                                struct ext2_inode_large *inode)
 300 {
 301         struct ext2_ext_attr_header *header;
 302         void *block_buf = NULL;
 303         blk64_t blk;
 304         errcode_t err;
 305         struct ext2_inode_large i;
 306
 307         /* Read inode? */
 308         if (inode == NULL) {
 309                 err = ext2fs_read_inode_full(fs, ino, (struct ext2_inode *)&i,
 310                                              sizeof(struct ext2_inode_large));
 311                 if (err)
 312                         return err;
 313                 inode = &i;
 314         }
 315
 316         /* Do we already have an EA block? */
 317         blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
 318         if (blk == 0)
 319                 return 0;
 320
 321         /* Find block, zero it, write back */
 322         if ((blk < fs->super->s_first_data_block) ||
 323             (blk >= ext2fs_blocks_count(fs->super))) {
 324                 err = EXT2_ET_BAD_EA_BLOCK_NUM;
 325                 goto out;
 326         }
 327
 328         err = ext2fs_get_mem(fs->blocksize, &block_buf);
 329         if (err)
 330                 goto out;
 331
 332         err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
 333         if (err)
 334                 goto out2;
 335
 336         /* We only know how to deal with v2 EA blocks */
 337         header = (struct ext2_ext_attr_header *) block_buf;
 338         if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 339                 err = EXT2_ET_BAD_EA_HEADER;
 340                 goto out2;
 341         }
 342
 343         header->h_refcount--;
 344         err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
 345         if (err)
 346                 goto out2;
 347
 348         /* Erase link to block */
 349         ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, 0);
 350         if (header->h_refcount == 0)
 351                 ext2fs_block_alloc_stats2(fs, blk, -1);
 352         err = ext2fs_iblk_sub_blocks(fs, (struct ext2_inode *)inode, 1);
 353         if (err)
 354                 goto out2;
 355
 356         /* Write inode? */
 357         if (inode == &i) {
 358                 err = ext2fs_write_inode_full(fs, ino, (struct ext2_inode *)&i,
 359                                               sizeof(struct ext2_inode_large));
 360                 if (err)
 361                         goto out2;
 362         }
 363
 364 out2:
 365         ext2fs_free_mem(&block_buf);
 366 out:
 367         return err;
 368 }
 369
 370 static errcode_t prep_ea_block_for_write(ext2_filsys fs, ext2_ino_t ino,
 371                                          struct ext2_inode_large *inode)
 372 {
 373         struct ext2_ext_attr_header *header;
 374         void *block_buf = NULL;
 375         blk64_t blk, goal;
 376         errcode_t err;
 377
 378         /* Do we already have an EA block? */
 379         blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
 380         if (blk != 0) {
 381                 if ((blk < fs->super->s_first_data_block) ||
 382                     (blk >= ext2fs_blocks_count(fs->super))) {
 383                         err = EXT2_ET_BAD_EA_BLOCK_NUM;
 384                         goto out;
 385                 }
 386
 387                 err = ext2fs_get_mem(fs->blocksize, &block_buf);
 388                 if (err)
 389                         goto out;
 390
 391                 err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
 392                 if (err)
 393                         goto out2;
 394
 395                 /* We only know how to deal with v2 EA blocks */
 396                 header = (struct ext2_ext_attr_header *) block_buf;
 397                 if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 398                         err = EXT2_ET_BAD_EA_HEADER;
 399                         goto out2;
 400                 }
 401
 402                 /* Single-user block.  We're done here. */
 403                 if (header->h_refcount == 1)
 404                         goto out2;
 405
 406                 /* We need to CoW the block. */
 407                 header->h_refcount--;
 408                 err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
 409                 if (err)
 410                         goto out2;
 411         } else {
 412                 /* No block, we must increment i_blocks */
 413                 err = ext2fs_iblk_add_blocks(fs, (struct ext2_inode *)inode,
 414                                              1);
 415                 if (err)
 416                         goto out;
 417         }
 418
 419         /* Allocate a block */
 420         goal = ext2fs_find_inode_goal(fs, ino, (struct ext2_inode *)inode, 0);
 421         err = ext2fs_alloc_block2(fs, goal, NULL, &blk);
 422         if (err)
 423                 goto out2;
 424         ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, blk);
 425 out2:
 426         if (block_buf)
 427                 ext2fs_free_mem(&block_buf);
 428 out:
 429         return err;
 430 }
 431
 432
 433 static errcode_t write_xattrs_to_buffer(struct ext2_xattr_handle *handle,
 434                                         struct ext2_xattr **pos,
 435                                         void *entries_start,
 436                                         unsigned int storage_size,
 437                                         unsigned int value_offset_correction,
 438                                         int write_hash)
 439 {
 440         struct ext2_xattr *x = *pos;
 441         struct ext2_ext_attr_entry *e = entries_start;
 442         void *end = entries_start + storage_size;
 443         char *shortname;
 444         unsigned int entry_size, value_size;
 445         int idx, ret;
 446
 447         memset(entries_start, 0, storage_size);
 448         /* For all remaining x...  */
 449         for (; x < handle->attrs + handle->length; x++) {
 450                 if (!x->name)
 451                         continue;
 452
 453                 /* Calculate index and shortname position */
 454                 shortname = x->name;
 455                 ret = find_ea_index(x->name, &shortname, &idx);
 456
 457                 /* Calculate entry and value size */
 458                 entry_size = (sizeof(*e) + strlen(shortname) +
 459                               EXT2_EXT_ATTR_PAD - 1) &
 460                              ~(EXT2_EXT_ATTR_PAD - 1);
 461                 value_size = ((x->value_len + EXT2_EXT_ATTR_PAD - 1) /
 462                               EXT2_EXT_ATTR_PAD) * EXT2_EXT_ATTR_PAD;
 463
 464                 /*
 465                  * Would entry collide with value?
 466                  * Note that we must leave sufficient room for a (u32)0 to
 467                  * mark the end of the entries.
 468                  */
 469                 if ((void *)e + entry_size + sizeof(__u32) > end - value_size)
 470                         break;
 471
 472                 /* Fill out e appropriately */
 473                 e->e_name_len = strlen(shortname);
 474                 e->e_name_index = (ret ? idx : 0);
 475                 e->e_value_offs = end - value_size - (void *)entries_start +
 476                                 value_offset_correction;
 477                 e->e_value_block = 0;
 478                 e->e_value_size = x->value_len;
 479
 480                 /* Store name and value */
 481                 end -= value_size;
 482                 memcpy((void *)e + sizeof(*e), shortname, e->e_name_len);
 483                 memcpy(end, x->value, e->e_value_size);
 484
 485                 if (write_hash)
 486                         e->e_hash = ext2fs_ext_attr_hash_entry(e, end);
 487                 else
 488                         e->e_hash = 0;
 489
 490                 e = EXT2_EXT_ATTR_NEXT(e);
 491                 *(__u32 *)e = 0;
 492         }
 493         *pos = x;
 494
 495         return 0;
 496 }
 497
 498 errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle)
 499 {
 500         struct ext2_xattr *x;
 501         struct ext2_inode_large *inode;
 502         void *start, *block_buf = NULL;
 503         struct ext2_ext_attr_header *header;
 504         __u32 ea_inode_magic;
 505         blk64_t blk;
 506         unsigned int storage_size;
 507         unsigned int i;
 508         errcode_t err;
 509
 510         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
 511         i = EXT2_INODE_SIZE(handle->fs->super);
 512         if (i < sizeof(*inode))
 513                 i = sizeof(*inode);
 514         err = ext2fs_get_memzero(i, &inode);
 515         if (err)
 516                 return err;
 517
 518         err = ext2fs_read_inode_full(handle->fs, handle->ino,
 519                                      (struct ext2_inode *)inode,
 520                                      EXT2_INODE_SIZE(handle->fs->super));
 521         if (err)
 522                 goto out;
 523
 524         /* If extra_isize isn't set, we need to set it now */
 525         if (inode->i_extra_isize == 0 &&
 526             EXT2_INODE_SIZE(handle->fs->super) > EXT2_GOOD_OLD_INODE_SIZE) {
 527                 char *p = (char *)inode;
 528                 size_t extra = handle->fs->super->s_want_extra_isize;
 529
 530                 if (extra == 0)
 531                         extra = sizeof(__u32);
 532                 memset(p + EXT2_GOOD_OLD_INODE_SIZE, 0, extra);
 533                 inode->i_extra_isize = extra;
 534         }
 535
 536         /*
 537          * Force the inlinedata attr to the front and the empty entries
 538          * to the end.
 539          */
 540         x = handle->attrs;
 541         qsort(x, handle->length, sizeof(struct ext2_xattr), attr_compare);
 542
 543         /* Does the inode have space for EA? */
 544         if (inode->i_extra_isize < sizeof(inode->i_extra_isize) ||
 545             EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 546                                                   inode->i_extra_isize +
 547                                                   sizeof(__u32))
 548                 goto write_ea_block;
 549
 550         /* Write the inode EA */
 551         ea_inode_magic = EXT2_EXT_ATTR_MAGIC;
 552         memcpy(((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 553                inode->i_extra_isize, &ea_inode_magic, sizeof(__u32));
 554         storage_size = EXT2_INODE_SIZE(handle->fs->super) -
 555                 EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
 556                 sizeof(__u32);
 557         start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 558                 inode->i_extra_isize + sizeof(__u32);
 559
 560         err = write_xattrs_to_buffer(handle, &x, start, storage_size, 0, 0);
 561         if (err)
 562                 goto out;
 563
 564 write_ea_block:
 565         /* Are we done? */
 566         if (x >= handle->attrs + handle->count)
 567                 goto skip_ea_block;
 568
 569         /* Write the EA block */
 570         err = ext2fs_get_memzero(handle->fs->blocksize, &block_buf);
 571         if (err)
 572                 goto out;
 573
 574         storage_size = handle->fs->blocksize -
 575                 sizeof(struct ext2_ext_attr_header);
 576         start = block_buf + sizeof(struct ext2_ext_attr_header);
 577
 578         err = write_xattrs_to_buffer(handle, &x, start, storage_size,
 579                                      (void *)start - block_buf, 1);
 580         if (err)
 581                 goto out2;
 582
 583         if (x < handle->attrs + handle->length) {
 584                 err = EXT2_ET_EA_NO_SPACE;
 585                 goto out2;
 586         }
 587
 588         /* Write a header on the EA block */
 589         header = block_buf;
 590         header->h_magic = EXT2_EXT_ATTR_MAGIC;
 591         header->h_refcount = 1;
 592         header->h_blocks = 1;
 593
 594         /* Get a new block for writing */
 595         err = prep_ea_block_for_write(handle->fs, handle->ino, inode);
 596         if (err)
 597                 goto out2;
 598
 599         /* Finally, write the new EA block */
 600         blk = ext2fs_file_acl_block(handle->fs,
 601                                     (struct ext2_inode *)inode);
 602         err = ext2fs_write_ext_attr3(handle->fs, blk, block_buf,
 603                                      handle->ino);
 604         if (err)
 605                 goto out2;
 606
 607 skip_ea_block:
 608         blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
 609         if (!block_buf && blk) {
 610                 /* xattrs shrunk, free the block */
 611                 err = ext2fs_free_ext_attr(handle->fs, handle->ino, inode);
 612                 if (err)
 613                         goto out;
 614         }
 615
 616         /* Write the inode */
 617         err = ext2fs_write_inode_full(handle->fs, handle->ino,
 618                                       (struct ext2_inode *)inode,
 619                                       EXT2_INODE_SIZE(handle->fs->super));
 620         if (err)
 621                 goto out2;
 622
 623 out2:
 624         ext2fs_free_mem(&block_buf);
 625 out:
 626         ext2fs_free_mem(&inode);
 627         handle->dirty = 0;
 628         return err;
 629 }
 630
 631 static errcode_t read_xattrs_from_buffer(struct ext2_xattr_handle *handle,
 632                                          struct ext2_ext_attr_entry *entries,
 633                                          unsigned int storage_size,
 634                                          void *value_start,
 635                                          size_t *nr_read)
 636 {
 637         struct ext2_xattr *x;
 638         struct ext2_ext_attr_entry *entry, *end;
 639         const char *prefix;
 640         unsigned int remain, prefix_len;
 641         errcode_t err;
 642         unsigned int values_size = storage_size +
 643                         ((char *)entries - (char *)value_start);
 644
 645         x = handle->attrs;
 646         while (x->name)
 647                 x++;
 648
 649         /* find the end */
 650         end = entries;
 651         remain = storage_size;
 652         while (remain >= sizeof(struct ext2_ext_attr_entry) &&
 653                !EXT2_EXT_IS_LAST_ENTRY(end)) {
 654
 655                 /* header eats this space */
 656                 remain -= sizeof(struct ext2_ext_attr_entry);
 657
 658                 /* is attribute name valid? */
 659                 if (EXT2_EXT_ATTR_SIZE(end->e_name_len) > remain)
 660                         return EXT2_ET_EA_BAD_NAME_LEN;
 661
 662                 /* attribute len eats this space */
 663                 remain -= EXT2_EXT_ATTR_SIZE(end->e_name_len);
 664                 end = EXT2_EXT_ATTR_NEXT(end);
 665         }
 666
 667         entry = entries;
 668         remain = storage_size;
 669         while (remain >= sizeof(struct ext2_ext_attr_entry) &&
 670                !EXT2_EXT_IS_LAST_ENTRY(entry)) {
 671                 __u32 hash;
 672
 673                 /* header eats this space */
 674                 remain -= sizeof(struct ext2_ext_attr_entry);
 675
 676                 /* attribute len eats this space */
 677                 remain -= EXT2_EXT_ATTR_SIZE(entry->e_name_len);
 678
 679                 /* check value size */
 680                 if (entry->e_value_size > remain)
 681                         return EXT2_ET_EA_BAD_VALUE_SIZE;
 682
 683                 if (entry->e_value_offs + entry->e_value_size > values_size)
 684                         return EXT2_ET_EA_BAD_VALUE_OFFSET;
 685
 686                 if (entry->e_value_size > 0 &&
 687                     value_start + entry->e_value_offs <
 688                     (void *)end + sizeof(__u32))
 689                         return EXT2_ET_EA_BAD_VALUE_OFFSET;
 690
 691                 /* e_value_block must be 0 in inode's ea */
 692                 if (entry->e_value_block != 0)
 693                         return EXT2_ET_BAD_EA_BLOCK_NUM;
 694
 695                 hash = ext2fs_ext_attr_hash_entry(entry, value_start +
 696                                                          entry->e_value_offs);
 697
 698                 /* e_hash may be 0 in older inode's ea */
 699                 if (entry->e_hash != 0 && entry->e_hash != hash)
 700                         return EXT2_ET_BAD_EA_HASH;
 701
 702                 remain -= entry->e_value_size;
 703
 704                 /* Allocate space for more attrs? */
 705                 if (x == handle->attrs + handle->length) {
 706                         err = ext2fs_xattrs_expand(handle, 4);
 707                         if (err)
 708                                 return err;
 709                         x = handle->attrs + handle->length - 4;
 710                 }
 711
 712                 /* Extract name/value */
 713                 prefix = find_ea_prefix(entry->e_name_index);
 714                 prefix_len = (prefix ? strlen(prefix) : 0);
 715                 err = ext2fs_get_memzero(entry->e_name_len + prefix_len + 1,
 716                                          &x->name);
 717                 if (err)
 718                         return err;
 719                 if (prefix)
 720                         memcpy(x->name, prefix, prefix_len);
 721                 if (entry->e_name_len)
 722                         memcpy(x->name + prefix_len,
 723                                (void *)entry + sizeof(*entry),
 724                                entry->e_name_len);
 725
 726                 err = ext2fs_get_mem(entry->e_value_size, &x->value);
 727                 if (err)
 728                         return err;
 729                 x->value_len = entry->e_value_size;
 730                 memcpy(x->value, value_start + entry->e_value_offs,
 731                        entry->e_value_size);
 732                 x++;
 733                 (*nr_read)++;
 734                 entry = EXT2_EXT_ATTR_NEXT(entry);
 735         }
 736
 737         return 0;
 738 }
 739
 740 static void xattrs_free_keys(struct ext2_xattr_handle *h)
 741 {
 742         struct ext2_xattr *a = h->attrs;
 743         size_t i;
 744
 745         for (i = 0; i < h->length; i++) {
 746                 if (a[i].name)
 747                         ext2fs_free_mem(&a[i].name);
 748                 if (a[i].value)
 749                         ext2fs_free_mem(&a[i].value);
 750         }
 751         h->count = 0;
 752 }
 753
 754 errcode_t ext2fs_xattrs_read(struct ext2_xattr_handle *handle)
 755 {
 756         struct ext2_inode_large *inode;
 757         struct ext2_ext_attr_header *header;
 758         __u32 ea_inode_magic;
 759         unsigned int storage_size;
 760         void *start, *block_buf = NULL;
 761         blk64_t blk;
 762         int i;
 763         errcode_t err;
 764
 765         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
 766         i = EXT2_INODE_SIZE(handle->fs->super);
 767         if (i < sizeof(*inode))
 768                 i = sizeof(*inode);
 769         err = ext2fs_get_memzero(i, &inode);
 770         if (err)
 771                 return err;
 772
 773         err = ext2fs_read_inode_full(handle->fs, handle->ino,
 774                                      (struct ext2_inode *)inode,
 775                                      EXT2_INODE_SIZE(handle->fs->super));
 776         if (err)
 777                 goto out;
 778
 779         xattrs_free_keys(handle);
 780
 781         /* Does the inode have space for EA? */
 782         if (inode->i_extra_isize < sizeof(inode->i_extra_isize) ||
 783             EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 784                                                   inode->i_extra_isize +
 785                                                   sizeof(__u32))
 786                 goto read_ea_block;
 787
 788         /* Look for EA in the inode */
 789         memcpy(&ea_inode_magic, ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 790                inode->i_extra_isize, sizeof(__u32));
 791         if (ea_inode_magic == EXT2_EXT_ATTR_MAGIC) {
 792                 storage_size = EXT2_INODE_SIZE(handle->fs->super) -
 793                         EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
 794                         sizeof(__u32);
 795                 start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 796                         inode->i_extra_isize + sizeof(__u32);
 797
 798                 err = read_xattrs_from_buffer(handle, start, storage_size,
 799                                               start, &handle->count);
 800                 if (err)
 801                         goto out;
 802         }
 803
 804 read_ea_block:
 805         /* Look for EA in a separate EA block */
 806         blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
 807         if (blk != 0) {
 808                 if ((blk < handle->fs->super->s_first_data_block) ||
 809                     (blk >= ext2fs_blocks_count(handle->fs->super))) {
 810                         err = EXT2_ET_BAD_EA_BLOCK_NUM;
 811                         goto out;
 812                 }
 813
 814                 err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
 815                 if (err)
 816                         goto out;
 817
 818                 err = ext2fs_read_ext_attr3(handle->fs, blk, block_buf,
 819                                             handle->ino);
 820                 if (err)
 821                         goto out3;
 822
 823                 /* We only know how to deal with v2 EA blocks */
 824                 header = (struct ext2_ext_attr_header *) block_buf;
 825                 if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 826                         err = EXT2_ET_BAD_EA_HEADER;
 827                         goto out3;
 828                 }
 829
 830                 /* Read EAs */
 831                 storage_size = handle->fs->blocksize -
 832                         sizeof(struct ext2_ext_attr_header);
 833                 start = block_buf + sizeof(struct ext2_ext_attr_header);
 834                 err = read_xattrs_from_buffer(handle, start, storage_size,
 835                                               block_buf, &handle->count);
 836                 if (err)
 837                         goto out3;
 838
 839                 ext2fs_free_mem(&block_buf);
 840         }
 841
 842         ext2fs_free_mem(&block_buf);
 843         ext2fs_free_mem(&inode);
 844         return 0;
 845
 846 out3:
 847         ext2fs_free_mem(&block_buf);
 848 out:
 849         ext2fs_free_mem(&inode);
 850         return err;
 851 }
 852
 853 errcode_t ext2fs_xattrs_iterate(struct ext2_xattr_handle *h,
 854                                 int (*func)(char *name, char *value,
 855                                             size_t value_len, void *data),
 856                                 void *data)
 857 {
 858         struct ext2_xattr *x;
 859         int ret;
 860
 861         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
 862         for (x = h->attrs; x < h->attrs + h->length; x++) {
 863                 if (!x->name)
 864                         continue;
 865
 866                 ret = func(x->name, x->value, x->value_len, data);
 867                 if (ret & XATTR_CHANGED)
 868                         h->dirty = 1;
 869                 if (ret & XATTR_ABORT)
 870                         return 0;
 871         }
 872
 873         return 0;
 874 }
 875
 876 errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
 877                            void **value, size_t *value_len)
 878 {
 879         struct ext2_xattr *x;
 880         void *val;
 881         errcode_t err;
 882
 883         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
 884         for (x = h->attrs; x < h->attrs + h->length; x++) {
 885                 if (!x->name)
 886                         continue;
 887
 888                 if (strcmp(x->name, key) == 0) {
 889                         err = ext2fs_get_mem(x->value_len, &val);
 890                         if (err)
 891                                 return err;
 892                         memcpy(val, x->value, x->value_len);
 893                         *value = val;
 894                         *value_len = x->value_len;
 895                         return 0;
 896                 }
 897         }
 898
 899         return EXT2_ET_EA_KEY_NOT_FOUND;
 900 }
 901
 902 errcode_t ext2fs_xattr_inode_max_size(ext2_filsys fs, ext2_ino_t ino,
 903                                       size_t *size)
 904 {
 905         struct ext2_ext_attr_entry *entry;
 906         struct ext2_inode_large *inode;
 907         __u32 ea_inode_magic;
 908         unsigned int minoff;
 909         void *start;
 910         int i;
 911         errcode_t err;
 912
 913         i = EXT2_INODE_SIZE(fs->super);
 914         if (i < sizeof(*inode))
 915                 i = sizeof(*inode);
 916         err = ext2fs_get_memzero(i, &inode);
 917         if (err)
 918                 return err;
 919
 920         err = ext2fs_read_inode_full(fs, ino, (struct ext2_inode *)inode,
 921                                      EXT2_INODE_SIZE(fs->super));
 922         if (err)
 923                 goto out;
 924
 925         /* Does the inode have size for EA? */
 926         if (EXT2_INODE_SIZE(fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 927                                                   inode->i_extra_isize +
 928                                                   sizeof(__u32)) {
 929                 err = EXT2_ET_INLINE_DATA_NO_SPACE;
 930                 goto out;
 931         }
 932
 933         minoff = EXT2_INODE_SIZE(fs->super) - sizeof(*inode) - sizeof(__u32);
 934         memcpy(&ea_inode_magic, ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 935                inode->i_extra_isize, sizeof(__u32));
 936         if (ea_inode_magic == EXT2_EXT_ATTR_MAGIC) {
 937                 /* has xattrs.  calculate the size */
 938                 start= ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 939                         inode->i_extra_isize + sizeof(__u32);
 940                 entry = start;
 941                 while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
 942                         if (!entry->e_value_block && entry->e_value_size) {
 943                                 unsigned int offs = entry->e_value_offs;
 944                                 if (offs < minoff)
 945                                         minoff = offs;
 946                         }
 947                         entry = EXT2_EXT_ATTR_NEXT(entry);
 948                 }
 949                 *size = minoff - ((char *)entry - (char *)start) - sizeof(__u32);
 950         } else {
 951                 /* no xattr.  return a maximum size */
 952                 *size = EXT2_EXT_ATTR_SIZE(minoff -
 953                                            EXT2_EXT_ATTR_LEN(strlen("data")) -
 954                                            EXT2_EXT_ATTR_ROUND - sizeof(__u32));
 955         }
 956
 957 out:
 958         ext2fs_free_mem(&inode);
 959         return err;
 960 }
 961
 962 errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
 963                            const char *key,
 964                            const void *value,
 965                            size_t value_len)
 966 {
 967         struct ext2_xattr *x, *last_empty;
 968         char *new_value;
 969         errcode_t err;
 970
 971         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
 972         last_empty = NULL;
 973         for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
 974                 if (!x->name) {
 975                         last_empty = x;
 976                         continue;
 977                 }
 978
 979                 /* Replace xattr */
 980                 if (strcmp(x->name, key) == 0) {
 981                         err = ext2fs_get_mem(value_len, &new_value);
 982                         if (err)
 983                                 return err;
 984                         memcpy(new_value, value, value_len);
 985                         ext2fs_free_mem(&x->value);
 986                         x->value = new_value;
 987                         x->value_len = value_len;
 988                         handle->dirty = 1;
 989                         return 0;
 990                 }
 991         }
 992
 993         /* Add attr to empty slot */
 994         if (last_empty) {
 995                 err = ext2fs_get_mem(strlen(key) + 1, &last_empty->name);
 996                 if (err)
 997                         return err;
 998                 strcpy(last_empty->name, key);
 999
1000                 err = ext2fs_get_mem(value_len, &last_empty->value);
1001                 if (err)
1002                         return err;
1003                 memcpy(last_empty->value, value, value_len);
1004                 last_empty->value_len = value_len;
1005                 handle->dirty = 1;
1006                 handle->count++;
1007                 return 0;
1008         }
1009
1010         /* Expand array, append slot */
1011         err = ext2fs_xattrs_expand(handle, 4);
1012         if (err)
1013                 return err;
1014
1015         x = handle->attrs + handle->length - 4;
1016         err = ext2fs_get_mem(strlen(key) + 1, &x->name);
1017         if (err)
1018                 return err;
1019         strcpy(x->name, key);
1020
1021         err = ext2fs_get_mem(value_len, &x->value);
1022         if (err)
1023                 return err;
1024         memcpy(x->value, value, value_len);
1025         x->value_len = value_len;
1026         handle->dirty = 1;
1027         handle->count++;
1028         return 0;
1029 }
1030
1031 errcode_t ext2fs_xattr_remove(struct ext2_xattr_handle *handle,
1032                               const char *key)
1033 {
1034         struct ext2_xattr *x;
1035
1036         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
1037         for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
1038                 if (!x->name)
1039                         continue;
1040
1041                 if (strcmp(x->name, key) == 0) {
1042                         ext2fs_free_mem(&x->name);
1043                         ext2fs_free_mem(&x->value);
1044                         x->value_len = 0;
1045                         handle->dirty = 1;
1046                         handle->count--;
1047                         return 0;
1048                 }
1049         }
1050
1051         /* no key found, success! */
1052         return 0;
1053 }
1054
1055 errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
1056                              struct ext2_xattr_handle **handle)
1057 {
1058         struct ext2_xattr_handle *h;
1059         errcode_t err;
1060
1061         if (!EXT2_HAS_COMPAT_FEATURE(fs->super,
1062                                      EXT2_FEATURE_COMPAT_EXT_ATTR) &&
1063             !EXT2_HAS_INCOMPAT_FEATURE(fs->super,
1064                                      EXT4_FEATURE_INCOMPAT_INLINE_DATA))
1065                 return EXT2_ET_MISSING_EA_FEATURE;
1066
1067         err = ext2fs_get_memzero(sizeof(*h), &h);
1068         if (err)
1069                 return err;
1070
1071         h->magic = EXT2_ET_MAGIC_EA_HANDLE;
1072         h->length = 4;
1073         err = ext2fs_get_arrayzero(h->length, sizeof(struct ext2_xattr),
1074                                    &h->attrs);
1075         if (err) {
1076                 ext2fs_free_mem(&h);
1077                 return err;
1078         }
1079         h->count = 0;
1080         h->ino = ino;
1081         h->fs = fs;
1082         *handle = h;
1083         return 0;
1084 }
1085
1086 errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle)
1087 {
1088         struct ext2_xattr_handle *h = *handle;
1089         errcode_t err;
1090
1091         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
1092         if (h->dirty) {
1093                 err = ext2fs_xattrs_write(h);
1094                 if (err)
1095                         return err;
1096         }
1097
1098         xattrs_free_keys(h);
1099         ext2fs_free_mem(&h->attrs);
1100         ext2fs_free_mem(handle);
1101         return 0;
1102 }
1103
1104 errcode_t ext2fs_xattrs_count(struct ext2_xattr_handle *handle, size_t *count)
1105 {
1106         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
1107         *count = handle->count;
1108         return 0;
1109 }