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 static int find_ea_index(char *fullname, char **name, int *index);
 258
 259 /* Push empty attributes to the end and inlinedata to the front. */
 260 static int attr_compare(const void *a, const void *b)
 261 {
 262         const struct ext2_xattr *xa = a, *xb = b;
 263         char *xa_suffix, *xb_suffix;
 264         int xa_idx, xb_idx;
 265         int cmp;
 266
 267         if (xa->name == NULL)
 268                 return +1;
 269         else if (xb->name == NULL)
 270                 return -1;
 271         else if (!strcmp(xa->name, "system.data"))
 272                 return -1;
 273         else if (!strcmp(xb->name, "system.data"))
 274                 return +1;
 275
 276         /*
 277          * Duplicate the kernel's sorting algorithm because xattr blocks
 278          * require sorted keys.
 279          */
 280         xa_suffix = xa->name;
 281         xb_suffix = xb->name;
 282         xa_idx = xb_idx = 0;
 283         find_ea_index(xa->name, &xa_suffix, &xa_idx);
 284         find_ea_index(xb->name, &xb_suffix, &xb_idx);
 285         cmp = xa_idx - xb_idx;
 286         if (cmp)
 287                 return cmp;
 288         cmp = strlen(xa_suffix) - strlen(xb_suffix);
 289         if (cmp)
 290                 return cmp;
 291         cmp = strcmp(xa_suffix, xb_suffix);
 292         return cmp;
 293 }
 294
 295 static const char *find_ea_prefix(int index)
 296 {
 297         struct ea_name_index *e;
 298
 299         for (e = ea_names; e->name; e++)
 300                 if (e->index == index)
 301                         return e->name;
 302
 303         return NULL;
 304 }
 305
 306 static int find_ea_index(char *fullname, char **name, int *index)
 307 {
 308         struct ea_name_index *e;
 309
 310         for (e = ea_names; e->name; e++) {
 311                 if (memcmp(fullname, e->name, strlen(e->name)) == 0) {
 312                         *name = (char *)fullname + strlen(e->name);
 313                         *index = e->index;
 314                         return 1;
 315                 }
 316         }
 317         return 0;
 318 }
 319
 320 errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
 321                                struct ext2_inode_large *inode)
 322 {
 323         struct ext2_ext_attr_header *header;
 324         void *block_buf = NULL;
 325         blk64_t blk;
 326         errcode_t err;
 327         struct ext2_inode_large i;
 328
 329         /* Read inode? */
 330         if (inode == NULL) {
 331                 err = ext2fs_read_inode_full(fs, ino, (struct ext2_inode *)&i,
 332                                              sizeof(struct ext2_inode_large));
 333                 if (err)
 334                         return err;
 335                 inode = &i;
 336         }
 337
 338         /* Do we already have an EA block? */
 339         blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
 340         if (blk == 0)
 341                 return 0;
 342
 343         /* Find block, zero it, write back */
 344         if ((blk < fs->super->s_first_data_block) ||
 345             (blk >= ext2fs_blocks_count(fs->super))) {
 346                 err = EXT2_ET_BAD_EA_BLOCK_NUM;
 347                 goto out;
 348         }
 349
 350         err = ext2fs_get_mem(fs->blocksize, &block_buf);
 351         if (err)
 352                 goto out;
 353
 354         err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
 355         if (err)
 356                 goto out2;
 357
 358         /* We only know how to deal with v2 EA blocks */
 359         header = (struct ext2_ext_attr_header *) block_buf;
 360         if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 361                 err = EXT2_ET_BAD_EA_HEADER;
 362                 goto out2;
 363         }
 364
 365         header->h_refcount--;
 366         err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
 367         if (err)
 368                 goto out2;
 369
 370         /* Erase link to block */
 371         ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, 0);
 372         if (header->h_refcount == 0)
 373                 ext2fs_block_alloc_stats2(fs, blk, -1);
 374         err = ext2fs_iblk_sub_blocks(fs, (struct ext2_inode *)inode, 1);
 375         if (err)
 376                 goto out2;
 377
 378         /* Write inode? */
 379         if (inode == &i) {
 380                 err = ext2fs_write_inode_full(fs, ino, (struct ext2_inode *)&i,
 381                                               sizeof(struct ext2_inode_large));
 382                 if (err)
 383                         goto out2;
 384         }
 385
 386 out2:
 387         ext2fs_free_mem(&block_buf);
 388 out:
 389         return err;
 390 }
 391
 392 static errcode_t prep_ea_block_for_write(ext2_filsys fs, ext2_ino_t ino,
 393                                          struct ext2_inode_large *inode)
 394 {
 395         struct ext2_ext_attr_header *header;
 396         void *block_buf = NULL;
 397         blk64_t blk, goal;
 398         errcode_t err;
 399
 400         /* Do we already have an EA block? */
 401         blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
 402         if (blk != 0) {
 403                 if ((blk < fs->super->s_first_data_block) ||
 404                     (blk >= ext2fs_blocks_count(fs->super))) {
 405                         err = EXT2_ET_BAD_EA_BLOCK_NUM;
 406                         goto out;
 407                 }
 408
 409                 err = ext2fs_get_mem(fs->blocksize, &block_buf);
 410                 if (err)
 411                         goto out;
 412
 413                 err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
 414                 if (err)
 415                         goto out2;
 416
 417                 /* We only know how to deal with v2 EA blocks */
 418                 header = (struct ext2_ext_attr_header *) block_buf;
 419                 if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 420                         err = EXT2_ET_BAD_EA_HEADER;
 421                         goto out2;
 422                 }
 423
 424                 /* Single-user block.  We're done here. */
 425                 if (header->h_refcount == 1)
 426                         goto out2;
 427
 428                 /* We need to CoW the block. */
 429                 header->h_refcount--;
 430                 err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
 431                 if (err)
 432                         goto out2;
 433         } else {
 434                 /* No block, we must increment i_blocks */
 435                 err = ext2fs_iblk_add_blocks(fs, (struct ext2_inode *)inode,
 436                                              1);
 437                 if (err)
 438                         goto out;
 439         }
 440
 441         /* Allocate a block */
 442         goal = ext2fs_find_inode_goal(fs, ino, (struct ext2_inode *)inode, 0);
 443         err = ext2fs_alloc_block2(fs, goal, NULL, &blk);
 444         if (err)
 445                 goto out2;
 446         ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, blk);
 447 out2:
 448         if (block_buf)
 449                 ext2fs_free_mem(&block_buf);
 450 out:
 451         return err;
 452 }
 453
 454
 455 static errcode_t write_xattrs_to_buffer(struct ext2_xattr_handle *handle,
 456                                         struct ext2_xattr **pos,
 457                                         void *entries_start,
 458                                         unsigned int storage_size,
 459                                         unsigned int value_offset_correction,
 460                                         int write_hash)
 461 {
 462         struct ext2_xattr *x = *pos;
 463         struct ext2_ext_attr_entry *e = entries_start;
 464         char *end = (char *) entries_start + storage_size;
 465         char *shortname;
 466         unsigned int entry_size, value_size;
 467         int idx, ret;
 468
 469         memset(entries_start, 0, storage_size);
 470         /* For all remaining x...  */
 471         for (; x < handle->attrs + handle->length; x++) {
 472                 if (!x->name)
 473                         continue;
 474
 475                 /* Calculate index and shortname position */
 476                 shortname = x->name;
 477                 ret = find_ea_index(x->name, &shortname, &idx);
 478
 479                 /* Calculate entry and value size */
 480                 entry_size = (sizeof(*e) + strlen(shortname) +
 481                               EXT2_EXT_ATTR_PAD - 1) &
 482                              ~(EXT2_EXT_ATTR_PAD - 1);
 483                 value_size = ((x->value_len + EXT2_EXT_ATTR_PAD - 1) /
 484                               EXT2_EXT_ATTR_PAD) * EXT2_EXT_ATTR_PAD;
 485
 486                 /*
 487                  * Would entry collide with value?
 488                  * Note that we must leave sufficient room for a (u32)0 to
 489                  * mark the end of the entries.
 490                  */
 491                 if ((char *)e + entry_size + sizeof(__u32) > end - value_size)
 492                         break;
 493
 494                 /* Fill out e appropriately */
 495                 e->e_name_len = strlen(shortname);
 496                 e->e_name_index = (ret ? idx : 0);
 497                 e->e_value_offs = end - value_size - (char *)entries_start +
 498                                 value_offset_correction;
 499                 e->e_value_block = 0;
 500                 e->e_value_size = x->value_len;
 501
 502                 /* Store name and value */
 503                 end -= value_size;
 504                 memcpy((char *)e + sizeof(*e), shortname, e->e_name_len);
 505                 memcpy(end, x->value, e->e_value_size);
 506
 507                 if (write_hash)
 508                         e->e_hash = ext2fs_ext_attr_hash_entry(e, end);
 509                 else
 510                         e->e_hash = 0;
 511
 512                 e = EXT2_EXT_ATTR_NEXT(e);
 513                 *(__u32 *)e = 0;
 514         }
 515         *pos = x;
 516
 517         return 0;
 518 }
 519
 520 errcode_t ext2fs_xattrs_write(struct ext2_xattr_handle *handle)
 521 {
 522         struct ext2_xattr *x;
 523         struct ext2_inode_large *inode;
 524         char *start, *block_buf = NULL;
 525         struct ext2_ext_attr_header *header;
 526         __u32 ea_inode_magic;
 527         blk64_t blk;
 528         unsigned int storage_size;
 529         unsigned int i;
 530         errcode_t err;
 531
 532         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
 533         i = EXT2_INODE_SIZE(handle->fs->super);
 534         if (i < sizeof(*inode))
 535                 i = sizeof(*inode);
 536         err = ext2fs_get_memzero(i, &inode);
 537         if (err)
 538                 return err;
 539
 540         err = ext2fs_read_inode_full(handle->fs, handle->ino,
 541                                      (struct ext2_inode *)inode,
 542                                      EXT2_INODE_SIZE(handle->fs->super));
 543         if (err)
 544                 goto out;
 545
 546         /* If extra_isize isn't set, we need to set it now */
 547         if (inode->i_extra_isize == 0 &&
 548             EXT2_INODE_SIZE(handle->fs->super) > EXT2_GOOD_OLD_INODE_SIZE) {
 549                 char *p = (char *)inode;
 550                 size_t extra = handle->fs->super->s_want_extra_isize;
 551
 552                 if (extra == 0)
 553                         extra = sizeof(__u32);
 554                 memset(p + EXT2_GOOD_OLD_INODE_SIZE, 0, extra);
 555                 inode->i_extra_isize = extra;
 556         }
 557
 558         /*
 559          * Force the inlinedata attr to the front and the empty entries
 560          * to the end.
 561          */
 562         x = handle->attrs;
 563         qsort(x, handle->length, sizeof(struct ext2_xattr), attr_compare);
 564
 565         /* Does the inode have space for EA? */
 566         if (inode->i_extra_isize < sizeof(inode->i_extra_isize) ||
 567             EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 568                                                   inode->i_extra_isize +
 569                                                   sizeof(__u32))
 570                 goto write_ea_block;
 571
 572         /* Write the inode EA */
 573         ea_inode_magic = EXT2_EXT_ATTR_MAGIC;
 574         memcpy(((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 575                inode->i_extra_isize, &ea_inode_magic, sizeof(__u32));
 576         storage_size = EXT2_INODE_SIZE(handle->fs->super) -
 577                 EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
 578                 sizeof(__u32);
 579         start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 580                 inode->i_extra_isize + sizeof(__u32);
 581
 582         err = write_xattrs_to_buffer(handle, &x, start, storage_size, 0, 0);
 583         if (err)
 584                 goto out;
 585
 586 write_ea_block:
 587         /* Are we done? */
 588         if (x >= handle->attrs + handle->count)
 589                 goto skip_ea_block;
 590
 591         /* Write the EA block */
 592         err = ext2fs_get_memzero(handle->fs->blocksize, &block_buf);
 593         if (err)
 594                 goto out;
 595
 596         storage_size = handle->fs->blocksize -
 597                 sizeof(struct ext2_ext_attr_header);
 598         start = block_buf + sizeof(struct ext2_ext_attr_header);
 599
 600         err = write_xattrs_to_buffer(handle, &x, start, storage_size,
 601                                      start - block_buf, 1);
 602         if (err)
 603                 goto out2;
 604
 605         if (x < handle->attrs + handle->length) {
 606                 err = EXT2_ET_EA_NO_SPACE;
 607                 goto out2;
 608         }
 609
 610         /* Write a header on the EA block */
 611         header = (struct ext2_ext_attr_header *) block_buf;
 612         header->h_magic = EXT2_EXT_ATTR_MAGIC;
 613         header->h_refcount = 1;
 614         header->h_blocks = 1;
 615
 616         /* Get a new block for writing */
 617         err = prep_ea_block_for_write(handle->fs, handle->ino, inode);
 618         if (err)
 619                 goto out2;
 620
 621         /* Finally, write the new EA block */
 622         blk = ext2fs_file_acl_block(handle->fs,
 623                                     (struct ext2_inode *)inode);
 624         err = ext2fs_write_ext_attr3(handle->fs, blk, block_buf,
 625                                      handle->ino);
 626         if (err)
 627                 goto out2;
 628
 629 skip_ea_block:
 630         blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
 631         if (!block_buf && blk) {
 632                 /* xattrs shrunk, free the block */
 633                 err = ext2fs_free_ext_attr(handle->fs, handle->ino, inode);
 634                 if (err)
 635                         goto out;
 636         }
 637
 638         /* Write the inode */
 639         err = ext2fs_write_inode_full(handle->fs, handle->ino,
 640                                       (struct ext2_inode *)inode,
 641                                       EXT2_INODE_SIZE(handle->fs->super));
 642         if (err)
 643                 goto out2;
 644
 645 out2:
 646         ext2fs_free_mem(&block_buf);
 647 out:
 648         ext2fs_free_mem(&inode);
 649         handle->dirty = 0;
 650         return err;
 651 }
 652
 653 static errcode_t read_xattrs_from_buffer(struct ext2_xattr_handle *handle,
 654                                          struct ext2_ext_attr_entry *entries,
 655                                          unsigned int storage_size,
 656                                          char *value_start,
 657                                          size_t *nr_read)
 658 {
 659         struct ext2_xattr *x;
 660         struct ext2_ext_attr_entry *entry, *end;
 661         const char *prefix;
 662         unsigned int remain, prefix_len;
 663         errcode_t err;
 664         unsigned int values_size = storage_size +
 665                         ((char *)entries - value_start);
 666
 667         x = handle->attrs;
 668         while (x->name)
 669                 x++;
 670
 671         /* find the end */
 672         end = entries;
 673         remain = storage_size;
 674         while (remain >= sizeof(struct ext2_ext_attr_entry) &&
 675                !EXT2_EXT_IS_LAST_ENTRY(end)) {
 676
 677                 /* header eats this space */
 678                 remain -= sizeof(struct ext2_ext_attr_entry);
 679
 680                 /* is attribute name valid? */
 681                 if (EXT2_EXT_ATTR_SIZE(end->e_name_len) > remain)
 682                         return EXT2_ET_EA_BAD_NAME_LEN;
 683
 684                 /* attribute len eats this space */
 685                 remain -= EXT2_EXT_ATTR_SIZE(end->e_name_len);
 686                 end = EXT2_EXT_ATTR_NEXT(end);
 687         }
 688
 689         entry = entries;
 690         remain = storage_size;
 691         while (remain >= sizeof(struct ext2_ext_attr_entry) &&
 692                !EXT2_EXT_IS_LAST_ENTRY(entry)) {
 693                 __u32 hash;
 694
 695                 /* header eats this space */
 696                 remain -= sizeof(struct ext2_ext_attr_entry);
 697
 698                 /* attribute len eats this space */
 699                 remain -= EXT2_EXT_ATTR_SIZE(entry->e_name_len);
 700
 701                 /* check value size */
 702                 if (entry->e_value_size > remain)
 703                         return EXT2_ET_EA_BAD_VALUE_SIZE;
 704
 705                 if (entry->e_value_offs + entry->e_value_size > values_size)
 706                         return EXT2_ET_EA_BAD_VALUE_OFFSET;
 707
 708                 if (entry->e_value_size > 0 &&
 709                     value_start + entry->e_value_offs <
 710                     (char *)end + sizeof(__u32))
 711                         return EXT2_ET_EA_BAD_VALUE_OFFSET;
 712
 713                 /* e_value_block must be 0 in inode's ea */
 714                 if (entry->e_value_block != 0)
 715                         return EXT2_ET_BAD_EA_BLOCK_NUM;
 716
 717                 hash = ext2fs_ext_attr_hash_entry(entry, value_start +
 718                                                          entry->e_value_offs);
 719
 720                 /* e_hash may be 0 in older inode's ea */
 721                 if (entry->e_hash != 0 && entry->e_hash != hash)
 722                         return EXT2_ET_BAD_EA_HASH;
 723
 724                 remain -= entry->e_value_size;
 725
 726                 /* Allocate space for more attrs? */
 727                 if (x == handle->attrs + handle->length) {
 728                         err = ext2fs_xattrs_expand(handle, 4);
 729                         if (err)
 730                                 return err;
 731                         x = handle->attrs + handle->length - 4;
 732                 }
 733
 734                 /* Extract name/value */
 735                 prefix = find_ea_prefix(entry->e_name_index);
 736                 prefix_len = (prefix ? strlen(prefix) : 0);
 737                 err = ext2fs_get_memzero(entry->e_name_len + prefix_len + 1,
 738                                          &x->name);
 739                 if (err)
 740                         return err;
 741                 if (prefix)
 742                         memcpy(x->name, prefix, prefix_len);
 743                 if (entry->e_name_len)
 744                         memcpy(x->name + prefix_len,
 745                                (char *)entry + sizeof(*entry),
 746                                entry->e_name_len);
 747
 748                 err = ext2fs_get_mem(entry->e_value_size, &x->value);
 749                 if (err)
 750                         return err;
 751                 x->value_len = entry->e_value_size;
 752                 memcpy(x->value, value_start + entry->e_value_offs,
 753                        entry->e_value_size);
 754                 x++;
 755                 (*nr_read)++;
 756                 entry = EXT2_EXT_ATTR_NEXT(entry);
 757         }
 758
 759         return 0;
 760 }
 761
 762 static void xattrs_free_keys(struct ext2_xattr_handle *h)
 763 {
 764         struct ext2_xattr *a = h->attrs;
 765         size_t i;
 766
 767         for (i = 0; i < h->length; i++) {
 768                 if (a[i].name)
 769                         ext2fs_free_mem(&a[i].name);
 770                 if (a[i].value)
 771                         ext2fs_free_mem(&a[i].value);
 772         }
 773         h->count = 0;
 774 }
 775
 776 errcode_t ext2fs_xattrs_read(struct ext2_xattr_handle *handle)
 777 {
 778         struct ext2_inode_large *inode;
 779         struct ext2_ext_attr_header *header;
 780         __u32 ea_inode_magic;
 781         unsigned int storage_size;
 782         char *start, *block_buf = NULL;
 783         blk64_t blk;
 784         size_t i;
 785         errcode_t err;
 786
 787         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
 788         i = EXT2_INODE_SIZE(handle->fs->super);
 789         if (i < sizeof(*inode))
 790                 i = sizeof(*inode);
 791         err = ext2fs_get_memzero(i, &inode);
 792         if (err)
 793                 return err;
 794
 795         err = ext2fs_read_inode_full(handle->fs, handle->ino,
 796                                      (struct ext2_inode *)inode,
 797                                      EXT2_INODE_SIZE(handle->fs->super));
 798         if (err)
 799                 goto out;
 800
 801         xattrs_free_keys(handle);
 802
 803         /* Does the inode have space for EA? */
 804         if (inode->i_extra_isize < sizeof(inode->i_extra_isize) ||
 805             EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 806                                                   inode->i_extra_isize +
 807                                                   sizeof(__u32))
 808                 goto read_ea_block;
 809
 810         /* Look for EA in the inode */
 811         memcpy(&ea_inode_magic, ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 812                inode->i_extra_isize, sizeof(__u32));
 813         if (ea_inode_magic == EXT2_EXT_ATTR_MAGIC) {
 814                 storage_size = EXT2_INODE_SIZE(handle->fs->super) -
 815                         EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
 816                         sizeof(__u32);
 817                 start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 818                         inode->i_extra_isize + sizeof(__u32);
 819
 820                 err = read_xattrs_from_buffer(handle,
 821                         (struct ext2_ext_attr_entry *) start, storage_size,
 822                                               start, &handle->count);
 823                 if (err)
 824                         goto out;
 825         }
 826
 827 read_ea_block:
 828         /* Look for EA in a separate EA block */
 829         blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
 830         if (blk != 0) {
 831                 if ((blk < handle->fs->super->s_first_data_block) ||
 832                     (blk >= ext2fs_blocks_count(handle->fs->super))) {
 833                         err = EXT2_ET_BAD_EA_BLOCK_NUM;
 834                         goto out;
 835                 }
 836
 837                 err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
 838                 if (err)
 839                         goto out;
 840
 841                 err = ext2fs_read_ext_attr3(handle->fs, blk, block_buf,
 842                                             handle->ino);
 843                 if (err)
 844                         goto out3;
 845
 846                 /* We only know how to deal with v2 EA blocks */
 847                 header = (struct ext2_ext_attr_header *) block_buf;
 848                 if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 849                         err = EXT2_ET_BAD_EA_HEADER;
 850                         goto out3;
 851                 }
 852
 853                 /* Read EAs */
 854                 storage_size = handle->fs->blocksize -
 855                         sizeof(struct ext2_ext_attr_header);
 856                 start = block_buf + sizeof(struct ext2_ext_attr_header);
 857                 err = read_xattrs_from_buffer(handle,
 858                         (struct ext2_ext_attr_entry *) start, storage_size,
 859                                               block_buf, &handle->count);
 860                 if (err)
 861                         goto out3;
 862
 863                 ext2fs_free_mem(&block_buf);
 864         }
 865
 866         ext2fs_free_mem(&block_buf);
 867         ext2fs_free_mem(&inode);
 868         return 0;
 869
 870 out3:
 871         ext2fs_free_mem(&block_buf);
 872 out:
 873         ext2fs_free_mem(&inode);
 874         return err;
 875 }
 876
 877 errcode_t ext2fs_xattrs_iterate(struct ext2_xattr_handle *h,
 878                                 int (*func)(char *name, char *value,
 879                                             size_t value_len, void *data),
 880                                 void *data)
 881 {
 882         struct ext2_xattr *x;
 883         int ret;
 884
 885         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
 886         for (x = h->attrs; x < h->attrs + h->length; x++) {
 887                 if (!x->name)
 888                         continue;
 889
 890                 ret = func(x->name, x->value, x->value_len, data);
 891                 if (ret & XATTR_CHANGED)
 892                         h->dirty = 1;
 893                 if (ret & XATTR_ABORT)
 894                         return 0;
 895         }
 896
 897         return 0;
 898 }
 899
 900 errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
 901                            void **value, size_t *value_len)
 902 {
 903         struct ext2_xattr *x;
 904         char *val;
 905         errcode_t err;
 906
 907         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
 908         for (x = h->attrs; x < h->attrs + h->length; x++) {
 909                 if (!x->name)
 910                         continue;
 911
 912                 if (strcmp(x->name, key) == 0) {
 913                         err = ext2fs_get_mem(x->value_len, &val);
 914                         if (err)
 915                                 return err;
 916                         memcpy(val, x->value, x->value_len);
 917                         *value = val;
 918                         *value_len = x->value_len;
 919                         return 0;
 920                 }
 921         }
 922
 923         return EXT2_ET_EA_KEY_NOT_FOUND;
 924 }
 925
 926 errcode_t ext2fs_xattr_inode_max_size(ext2_filsys fs, ext2_ino_t ino,
 927                                       size_t *size)
 928 {
 929         struct ext2_ext_attr_entry *entry;
 930         struct ext2_inode_large *inode;
 931         __u32 ea_inode_magic;
 932         unsigned int minoff;
 933         char *start;
 934         size_t i;
 935         errcode_t err;
 936
 937         i = EXT2_INODE_SIZE(fs->super);
 938         if (i < sizeof(*inode))
 939                 i = sizeof(*inode);
 940         err = ext2fs_get_memzero(i, &inode);
 941         if (err)
 942                 return err;
 943
 944         err = ext2fs_read_inode_full(fs, ino, (struct ext2_inode *)inode,
 945                                      EXT2_INODE_SIZE(fs->super));
 946         if (err)
 947                 goto out;
 948
 949         /* Does the inode have size for EA? */
 950         if (EXT2_INODE_SIZE(fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 951                                                   inode->i_extra_isize +
 952                                                   sizeof(__u32)) {
 953                 err = EXT2_ET_INLINE_DATA_NO_SPACE;
 954                 goto out;
 955         }
 956
 957         minoff = EXT2_INODE_SIZE(fs->super) - sizeof(*inode) - sizeof(__u32);
 958         memcpy(&ea_inode_magic, ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 959                inode->i_extra_isize, sizeof(__u32));
 960         if (ea_inode_magic == EXT2_EXT_ATTR_MAGIC) {
 961                 /* has xattrs.  calculate the size */
 962                 start= ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 963                         inode->i_extra_isize + sizeof(__u32);
 964                 entry = (struct ext2_ext_attr_entry *) start;
 965                 while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
 966                         if (!entry->e_value_block && entry->e_value_size) {
 967                                 unsigned int offs = entry->e_value_offs;
 968                                 if (offs < minoff)
 969                                         minoff = offs;
 970                         }
 971                         entry = EXT2_EXT_ATTR_NEXT(entry);
 972                 }
 973                 *size = minoff - ((char *)entry - (char *)start) - sizeof(__u32);
 974         } else {
 975                 /* no xattr.  return a maximum size */
 976                 *size = EXT2_EXT_ATTR_SIZE(minoff -
 977                                            EXT2_EXT_ATTR_LEN(strlen("data")) -
 978                                            EXT2_EXT_ATTR_ROUND - sizeof(__u32));
 979         }
 980
 981 out:
 982         ext2fs_free_mem(&inode);
 983         return err;
 984 }
 985
 986 errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
 987                            const char *key,
 988                            const void *value,
 989                            size_t value_len)
 990 {
 991         struct ext2_xattr *x, *last_empty;
 992         char *new_value;
 993         errcode_t err;
 994
 995         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
 996         last_empty = NULL;
 997         for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
 998                 if (!x->name) {
 999                         last_empty = x;
1000                         continue;
1001                 }
1002
1003                 /* Replace xattr */
1004                 if (strcmp(x->name, key) == 0) {
1005                         err = ext2fs_get_mem(value_len, &new_value);
1006                         if (err)
1007                                 return err;
1008                         memcpy(new_value, value, value_len);
1009                         ext2fs_free_mem(&x->value);
1010                         x->value = new_value;
1011                         x->value_len = value_len;
1012                         handle->dirty = 1;
1013                         return 0;
1014                 }
1015         }
1016
1017         /* Add attr to empty slot */
1018         if (last_empty) {
1019                 err = ext2fs_get_mem(strlen(key) + 1, &last_empty->name);
1020                 if (err)
1021                         return err;
1022                 strcpy(last_empty->name, key);
1023
1024                 err = ext2fs_get_mem(value_len, &last_empty->value);
1025                 if (err)
1026                         return err;
1027                 memcpy(last_empty->value, value, value_len);
1028                 last_empty->value_len = value_len;
1029                 handle->dirty = 1;
1030                 handle->count++;
1031                 return 0;
1032         }
1033
1034         /* Expand array, append slot */
1035         err = ext2fs_xattrs_expand(handle, 4);
1036         if (err)
1037                 return err;
1038
1039         x = handle->attrs + handle->length - 4;
1040         err = ext2fs_get_mem(strlen(key) + 1, &x->name);
1041         if (err)
1042                 return err;
1043         strcpy(x->name, key);
1044
1045         err = ext2fs_get_mem(value_len, &x->value);
1046         if (err)
1047                 return err;
1048         memcpy(x->value, value, value_len);
1049         x->value_len = value_len;
1050         handle->dirty = 1;
1051         handle->count++;
1052         return 0;
1053 }
1054
1055 errcode_t ext2fs_xattr_remove(struct ext2_xattr_handle *handle,
1056                               const char *key)
1057 {
1058         struct ext2_xattr *x;
1059
1060         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
1061         for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
1062                 if (!x->name)
1063                         continue;
1064
1065                 if (strcmp(x->name, key) == 0) {
1066                         ext2fs_free_mem(&x->name);
1067                         ext2fs_free_mem(&x->value);
1068                         x->value_len = 0;
1069                         handle->dirty = 1;
1070                         handle->count--;
1071                         return 0;
1072                 }
1073         }
1074
1075         /* no key found, success! */
1076         return 0;
1077 }
1078
1079 errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
1080                              struct ext2_xattr_handle **handle)
1081 {
1082         struct ext2_xattr_handle *h;
1083         errcode_t err;
1084
1085         if (!ext2fs_has_feature_xattr(fs->super) &&
1086             !ext2fs_has_feature_inline_data(fs->super))
1087                 return EXT2_ET_MISSING_EA_FEATURE;
1088
1089         err = ext2fs_get_memzero(sizeof(*h), &h);
1090         if (err)
1091                 return err;
1092
1093         h->magic = EXT2_ET_MAGIC_EA_HANDLE;
1094         h->length = 4;
1095         err = ext2fs_get_arrayzero(h->length, sizeof(struct ext2_xattr),
1096                                    &h->attrs);
1097         if (err) {
1098                 ext2fs_free_mem(&h);
1099                 return err;
1100         }
1101         h->count = 0;
1102         h->ino = ino;
1103         h->fs = fs;
1104         *handle = h;
1105         return 0;
1106 }
1107
1108 errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle)
1109 {
1110         struct ext2_xattr_handle *h = *handle;
1111         errcode_t err;
1112
1113         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
1114         if (h->dirty) {
1115                 err = ext2fs_xattrs_write(h);
1116                 if (err)
1117                         return err;
1118         }
1119
1120         xattrs_free_keys(h);
1121         ext2fs_free_mem(&h->attrs);
1122         ext2fs_free_mem(handle);
1123         return 0;
1124 }
1125
1126 errcode_t ext2fs_xattrs_count(struct ext2_xattr_handle *handle, size_t *count)
1127 {
1128         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
1129         *count = handle->count;
1130         return 0;
1131 }