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 void move_inline_data_to_front(struct ext2_xattr_handle *h)
 258 {
 259         struct ext2_xattr *x;
 260         struct ext2_xattr tmp;
 261
 262         for (x = h->attrs + 1; x < h->attrs + h->length; x++) {
 263                 if (!x->name)
 264                         continue;
 265
 266                 if (strcmp(x->name, "system.data") == 0) {
 267                         memcpy(&tmp, x, sizeof(tmp));
 268                         memcpy(x, h->attrs, sizeof(tmp));
 269                         memcpy(h->attrs, &tmp, sizeof(tmp));
 270                         return;
 271                 }
 272         }
 273 }
 274
 275 static const char *find_ea_prefix(int index)
 276 {
 277         struct ea_name_index *e;
 278
 279         for (e = ea_names; e->name; e++)
 280                 if (e->index == index)
 281                         return e->name;
 282
 283         return NULL;
 284 }
 285
 286 static int find_ea_index(const char *fullname, char **name, int *index)
 287 {
 288         struct ea_name_index *e;
 289
 290         for (e = ea_names; e->name; e++) {
 291                 if (memcmp(fullname, e->name, strlen(e->name)) == 0) {
 292                         *name = (char *)fullname + strlen(e->name);
 293                         *index = e->index;
 294                         return 1;
 295                 }
 296         }
 297         return 0;
 298 }
 299
 300 errcode_t ext2fs_free_ext_attr(ext2_filsys fs, ext2_ino_t ino,
 301                                struct ext2_inode_large *inode)
 302 {
 303         struct ext2_ext_attr_header *header;
 304         void *block_buf = NULL;
 305         blk64_t blk;
 306         errcode_t err;
 307         struct ext2_inode_large i;
 308
 309         /* Read inode? */
 310         if (inode == NULL) {
 311                 err = ext2fs_read_inode_full(fs, ino, (struct ext2_inode *)&i,
 312                                              sizeof(struct ext2_inode_large));
 313                 if (err)
 314                         return err;
 315                 inode = &i;
 316         }
 317
 318         /* Do we already have an EA block? */
 319         blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
 320         if (blk == 0)
 321                 return 0;
 322
 323         /* Find block, zero it, write back */
 324         if ((blk < fs->super->s_first_data_block) ||
 325             (blk >= ext2fs_blocks_count(fs->super))) {
 326                 err = EXT2_ET_BAD_EA_BLOCK_NUM;
 327                 goto out;
 328         }
 329
 330         err = ext2fs_get_mem(fs->blocksize, &block_buf);
 331         if (err)
 332                 goto out;
 333
 334         err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
 335         if (err)
 336                 goto out2;
 337
 338         /* We only know how to deal with v2 EA blocks */
 339         header = (struct ext2_ext_attr_header *) block_buf;
 340         if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 341                 err = EXT2_ET_BAD_EA_HEADER;
 342                 goto out2;
 343         }
 344
 345         header->h_refcount--;
 346         err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
 347         if (err)
 348                 goto out2;
 349
 350         /* Erase link to block */
 351         ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, 0);
 352         if (header->h_refcount == 0)
 353                 ext2fs_block_alloc_stats2(fs, blk, -1);
 354         err = ext2fs_iblk_sub_blocks(fs, (struct ext2_inode *)inode, 1);
 355         if (err)
 356                 goto out2;
 357
 358         /* Write inode? */
 359         if (inode == &i) {
 360                 err = ext2fs_write_inode_full(fs, ino, (struct ext2_inode *)&i,
 361                                               sizeof(struct ext2_inode_large));
 362                 if (err)
 363                         goto out2;
 364         }
 365
 366 out2:
 367         ext2fs_free_mem(&block_buf);
 368 out:
 369         return err;
 370 }
 371
 372 static errcode_t prep_ea_block_for_write(ext2_filsys fs, ext2_ino_t ino,
 373                                          struct ext2_inode_large *inode)
 374 {
 375         struct ext2_ext_attr_header *header;
 376         void *block_buf = NULL;
 377         dgrp_t grp;
 378         blk64_t blk, goal;
 379         errcode_t err;
 380
 381         /* Do we already have an EA block? */
 382         blk = ext2fs_file_acl_block(fs, (struct ext2_inode *)inode);
 383         if (blk != 0) {
 384                 if ((blk < fs->super->s_first_data_block) ||
 385                     (blk >= ext2fs_blocks_count(fs->super))) {
 386                         err = EXT2_ET_BAD_EA_BLOCK_NUM;
 387                         goto out;
 388                 }
 389
 390                 err = ext2fs_get_mem(fs->blocksize, &block_buf);
 391                 if (err)
 392                         goto out;
 393
 394                 err = ext2fs_read_ext_attr3(fs, blk, block_buf, ino);
 395                 if (err)
 396                         goto out2;
 397
 398                 /* We only know how to deal with v2 EA blocks */
 399                 header = (struct ext2_ext_attr_header *) block_buf;
 400                 if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 401                         err = EXT2_ET_BAD_EA_HEADER;
 402                         goto out2;
 403                 }
 404
 405                 /* Single-user block.  We're done here. */
 406                 if (header->h_refcount == 1)
 407                         goto out2;
 408
 409                 /* We need to CoW the block. */
 410                 header->h_refcount--;
 411                 err = ext2fs_write_ext_attr3(fs, blk, block_buf, ino);
 412                 if (err)
 413                         goto out2;
 414         } else {
 415                 /* No block, we must increment i_blocks */
 416                 err = ext2fs_iblk_add_blocks(fs, (struct ext2_inode *)inode,
 417                                              1);
 418                 if (err)
 419                         goto out;
 420         }
 421
 422         /* Allocate a block */
 423         grp = ext2fs_group_of_ino(fs, ino);
 424         goal = ext2fs_inode_table_loc(fs, grp);
 425         err = ext2fs_alloc_block2(fs, goal, NULL, &blk);
 426         if (err)
 427                 goto out2;
 428         ext2fs_file_acl_block_set(fs, (struct ext2_inode *)inode, blk);
 429 out2:
 430         if (block_buf)
 431                 ext2fs_free_mem(&block_buf);
 432 out:
 433         return err;
 434 }
 435
 436
 437 static errcode_t write_xattrs_to_buffer(struct ext2_xattr_handle *handle,
 438                                         struct ext2_xattr **pos,
 439                                         void *entries_start,
 440                                         unsigned int storage_size,
 441                                         unsigned int value_offset_correction)
 442 {
 443         struct ext2_xattr *x = *pos;
 444         struct ext2_ext_attr_entry *e = entries_start;
 445         void *end = entries_start + storage_size;
 446         char *shortname;
 447         unsigned int entry_size, value_size;
 448         int idx, ret;
 449
 450         memset(entries_start, 0, storage_size);
 451         /* For all remaining x...  */
 452         for (; x < handle->attrs + handle->length; x++) {
 453                 if (!x->name)
 454                         continue;
 455
 456                 /* Calculate index and shortname position */
 457                 shortname = x->name;
 458                 ret = find_ea_index(x->name, &shortname, &idx);
 459
 460                 /* Calculate entry and value size */
 461                 entry_size = (sizeof(*e) + strlen(shortname) +
 462                               EXT2_EXT_ATTR_PAD - 1) &
 463                              ~(EXT2_EXT_ATTR_PAD - 1);
 464                 value_size = ((x->value_len + EXT2_EXT_ATTR_PAD - 1) /
 465                               EXT2_EXT_ATTR_PAD) * EXT2_EXT_ATTR_PAD;
 466
 467                 /*
 468                  * Would entry collide with value?
 469                  * Note that we must leave sufficient room for a (u32)0 to
 470                  * mark the end of the entries.
 471                  */
 472                 if ((void *)e + entry_size + sizeof(__u32) > end - value_size)
 473                         break;
 474
 475                 /* Fill out e appropriately */
 476                 e->e_name_len = strlen(shortname);
 477                 e->e_name_index = (ret ? idx : 0);
 478                 e->e_value_offs = end - value_size - (void *)entries_start +
 479                                 value_offset_correction;
 480                 e->e_value_block = 0;
 481                 e->e_value_size = x->value_len;
 482
 483                 /* Store name and value */
 484                 end -= value_size;
 485                 memcpy((void *)e + sizeof(*e), shortname, e->e_name_len);
 486                 memcpy(end, x->value, e->e_value_size);
 487
 488                 e->e_hash = ext2fs_ext_attr_hash_entry(e, end);
 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         move_inline_data_to_front(handle);
 525
 526         x = handle->attrs;
 527         /* Does the inode have size for EA? */
 528         if (EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 529                                                   inode->i_extra_isize +
 530                                                   sizeof(__u32))
 531                 goto write_ea_block;
 532
 533         /* Write the inode EA */
 534         ea_inode_magic = EXT2_EXT_ATTR_MAGIC;
 535         memcpy(((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 536                inode->i_extra_isize, &ea_inode_magic, sizeof(__u32));
 537         storage_size = EXT2_INODE_SIZE(handle->fs->super) -
 538                 EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
 539                 sizeof(__u32);
 540         start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 541                 inode->i_extra_isize + sizeof(__u32);
 542
 543         err = write_xattrs_to_buffer(handle, &x, start, storage_size, 0);
 544         if (err)
 545                 goto out;
 546
 547         /* Are we done? */
 548         if (x == handle->attrs + handle->length)
 549                 goto skip_ea_block;
 550
 551 write_ea_block:
 552         /* Write the EA block */
 553         err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
 554         if (err)
 555                 goto out;
 556
 557         storage_size = handle->fs->blocksize -
 558                 sizeof(struct ext2_ext_attr_header);
 559         start = block_buf + sizeof(struct ext2_ext_attr_header);
 560
 561         err = write_xattrs_to_buffer(handle, &x, start, storage_size,
 562                                      (void *)start - block_buf);
 563         if (err)
 564                 goto out2;
 565
 566         if (x < handle->attrs + handle->length) {
 567                 err = EXT2_ET_EA_NO_SPACE;
 568                 goto out2;
 569         }
 570
 571         /* Write a header on the EA block */
 572         header = block_buf;
 573         header->h_magic = EXT2_EXT_ATTR_MAGIC;
 574         header->h_refcount = 1;
 575         header->h_blocks = 1;
 576
 577         /* Get a new block for writing */
 578         err = prep_ea_block_for_write(handle->fs, handle->ino, inode);
 579         if (err)
 580                 goto out2;
 581
 582         /* Finally, write the new EA block */
 583         blk = ext2fs_file_acl_block(handle->fs,
 584                                     (struct ext2_inode *)inode);
 585         err = ext2fs_write_ext_attr3(handle->fs, blk, block_buf,
 586                                      handle->ino);
 587         if (err)
 588                 goto out2;
 589
 590 skip_ea_block:
 591         blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
 592         if (!block_buf && blk) {
 593                 /* xattrs shrunk, free the block */
 594                 err = ext2fs_free_ext_attr(handle->fs, handle->ino, inode);
 595                 if (err)
 596                         goto out;
 597         }
 598
 599         /* Write the inode */
 600         err = ext2fs_write_inode_full(handle->fs, handle->ino,
 601                                       (struct ext2_inode *)inode,
 602                                       EXT2_INODE_SIZE(handle->fs->super));
 603         if (err)
 604                 goto out2;
 605
 606 out2:
 607         ext2fs_free_mem(&block_buf);
 608 out:
 609         ext2fs_free_mem(&inode);
 610         handle->dirty = 0;
 611         return err;
 612 }
 613
 614 static errcode_t read_xattrs_from_buffer(struct ext2_xattr_handle *handle,
 615                                          struct ext2_ext_attr_entry *entries,
 616                                          unsigned int storage_size,
 617                                          void *value_start,
 618                                          size_t *nr_read)
 619 {
 620         struct ext2_xattr *x;
 621         struct ext2_ext_attr_entry *entry, *end;
 622         const char *prefix;
 623         unsigned int remain, prefix_len;
 624         errcode_t err;
 625         unsigned int values_size = storage_size +
 626                         ((char *)entries - (char *)value_start);
 627
 628         x = handle->attrs;
 629         while (x->name)
 630                 x++;
 631
 632         /* find the end */
 633         end = entries;
 634         remain = storage_size;
 635         while (remain >= sizeof(struct ext2_ext_attr_entry) &&
 636                !EXT2_EXT_IS_LAST_ENTRY(end)) {
 637
 638                 /* header eats this space */
 639                 remain -= sizeof(struct ext2_ext_attr_entry);
 640
 641                 /* is attribute name valid? */
 642                 if (EXT2_EXT_ATTR_SIZE(end->e_name_len) > remain)
 643                         return EXT2_ET_EA_BAD_NAME_LEN;
 644
 645                 /* attribute len eats this space */
 646                 remain -= EXT2_EXT_ATTR_SIZE(end->e_name_len);
 647                 end = EXT2_EXT_ATTR_NEXT(end);
 648         }
 649
 650         entry = entries;
 651         remain = storage_size;
 652         while (remain >= sizeof(struct ext2_ext_attr_entry) &&
 653                !EXT2_EXT_IS_LAST_ENTRY(entry)) {
 654                 __u32 hash;
 655
 656                 /* header eats this space */
 657                 remain -= sizeof(struct ext2_ext_attr_entry);
 658
 659                 /* attribute len eats this space */
 660                 remain -= EXT2_EXT_ATTR_SIZE(entry->e_name_len);
 661
 662                 /* check value size */
 663                 if (entry->e_value_size > remain)
 664                         return EXT2_ET_EA_BAD_VALUE_SIZE;
 665
 666                 if (entry->e_value_offs + entry->e_value_size > values_size)
 667                         return EXT2_ET_EA_BAD_VALUE_OFFSET;
 668
 669                 if (entry->e_value_size > 0 &&
 670                     value_start + entry->e_value_offs <
 671                     (void *)end + sizeof(__u32))
 672                         return EXT2_ET_EA_BAD_VALUE_OFFSET;
 673
 674                 /* e_value_block must be 0 in inode's ea */
 675                 if (entry->e_value_block != 0)
 676                         return EXT2_ET_BAD_EA_BLOCK_NUM;
 677
 678                 hash = ext2fs_ext_attr_hash_entry(entry, value_start +
 679                                                          entry->e_value_offs);
 680
 681                 /* e_hash may be 0 in older inode's ea */
 682                 if (entry->e_hash != 0 && entry->e_hash != hash)
 683                         return EXT2_ET_BAD_EA_HASH;
 684
 685                 remain -= entry->e_value_size;
 686
 687                 /* Allocate space for more attrs? */
 688                 if (x == handle->attrs + handle->length) {
 689                         err = ext2fs_xattrs_expand(handle, 4);
 690                         if (err)
 691                                 return err;
 692                         x = handle->attrs + handle->length - 4;
 693                 }
 694
 695                 /* Extract name/value */
 696                 prefix = find_ea_prefix(entry->e_name_index);
 697                 prefix_len = (prefix ? strlen(prefix) : 0);
 698                 err = ext2fs_get_memzero(entry->e_name_len + prefix_len + 1,
 699                                          &x->name);
 700                 if (err)
 701                         return err;
 702                 if (prefix)
 703                         memcpy(x->name, prefix, prefix_len);
 704                 if (entry->e_name_len)
 705                         memcpy(x->name + prefix_len,
 706                                (void *)entry + sizeof(*entry),
 707                                entry->e_name_len);
 708
 709                 err = ext2fs_get_mem(entry->e_value_size, &x->value);
 710                 if (err)
 711                         return err;
 712                 x->value_len = entry->e_value_size;
 713                 memcpy(x->value, value_start + entry->e_value_offs,
 714                        entry->e_value_size);
 715                 x++;
 716                 (*nr_read)++;
 717                 entry = EXT2_EXT_ATTR_NEXT(entry);
 718         }
 719
 720         return 0;
 721 }
 722
 723 static void xattrs_free_keys(struct ext2_xattr_handle *h)
 724 {
 725         struct ext2_xattr *a = h->attrs;
 726         size_t i;
 727
 728         for (i = 0; i < h->length; i++) {
 729                 if (a[i].name)
 730                         ext2fs_free_mem(&a[i].name);
 731                 if (a[i].value)
 732                         ext2fs_free_mem(&a[i].value);
 733         }
 734         h->count = 0;
 735 }
 736
 737 errcode_t ext2fs_xattrs_read(struct ext2_xattr_handle *handle)
 738 {
 739         struct ext2_inode_large *inode;
 740         struct ext2_ext_attr_header *header;
 741         __u32 ea_inode_magic;
 742         unsigned int storage_size;
 743         void *start, *block_buf = NULL;
 744         blk64_t blk;
 745         int i;
 746         errcode_t err;
 747
 748         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
 749         i = EXT2_INODE_SIZE(handle->fs->super);
 750         if (i < sizeof(*inode))
 751                 i = sizeof(*inode);
 752         err = ext2fs_get_memzero(i, &inode);
 753         if (err)
 754                 return err;
 755
 756         err = ext2fs_read_inode_full(handle->fs, handle->ino,
 757                                      (struct ext2_inode *)inode,
 758                                      EXT2_INODE_SIZE(handle->fs->super));
 759         if (err)
 760                 goto out;
 761
 762         xattrs_free_keys(handle);
 763
 764         /* Does the inode have size for EA? */
 765         if (EXT2_INODE_SIZE(handle->fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 766                                                   inode->i_extra_isize +
 767                                                   sizeof(__u32))
 768                 goto read_ea_block;
 769
 770         /* Look for EA in the inode */
 771         memcpy(&ea_inode_magic, ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 772                inode->i_extra_isize, sizeof(__u32));
 773         if (ea_inode_magic == EXT2_EXT_ATTR_MAGIC) {
 774                 storage_size = EXT2_INODE_SIZE(handle->fs->super) -
 775                         EXT2_GOOD_OLD_INODE_SIZE - inode->i_extra_isize -
 776                         sizeof(__u32);
 777                 start = ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 778                         inode->i_extra_isize + sizeof(__u32);
 779
 780                 err = read_xattrs_from_buffer(handle, start, storage_size,
 781                                               start, &handle->count);
 782                 if (err)
 783                         goto out;
 784         }
 785
 786 read_ea_block:
 787         /* Look for EA in a separate EA block */
 788         blk = ext2fs_file_acl_block(handle->fs, (struct ext2_inode *)inode);
 789         if (blk != 0) {
 790                 if ((blk < handle->fs->super->s_first_data_block) ||
 791                     (blk >= ext2fs_blocks_count(handle->fs->super))) {
 792                         err = EXT2_ET_BAD_EA_BLOCK_NUM;
 793                         goto out;
 794                 }
 795
 796                 err = ext2fs_get_mem(handle->fs->blocksize, &block_buf);
 797                 if (err)
 798                         goto out;
 799
 800                 err = ext2fs_read_ext_attr3(handle->fs, blk, block_buf,
 801                                             handle->ino);
 802                 if (err)
 803                         goto out3;
 804
 805                 /* We only know how to deal with v2 EA blocks */
 806                 header = (struct ext2_ext_attr_header *) block_buf;
 807                 if (header->h_magic != EXT2_EXT_ATTR_MAGIC) {
 808                         err = EXT2_ET_BAD_EA_HEADER;
 809                         goto out3;
 810                 }
 811
 812                 /* Read EAs */
 813                 storage_size = handle->fs->blocksize -
 814                         sizeof(struct ext2_ext_attr_header);
 815                 start = block_buf + sizeof(struct ext2_ext_attr_header);
 816                 err = read_xattrs_from_buffer(handle, start, storage_size,
 817                                               block_buf, &handle->count);
 818                 if (err)
 819                         goto out3;
 820
 821                 ext2fs_free_mem(&block_buf);
 822         }
 823
 824         ext2fs_free_mem(&block_buf);
 825         ext2fs_free_mem(&inode);
 826         return 0;
 827
 828 out3:
 829         ext2fs_free_mem(&block_buf);
 830 out:
 831         ext2fs_free_mem(&inode);
 832         return err;
 833 }
 834
 835 errcode_t ext2fs_xattrs_iterate(struct ext2_xattr_handle *h,
 836                                 int (*func)(char *name, char *value,
 837                                             size_t value_len, void *data),
 838                                 void *data)
 839 {
 840         struct ext2_xattr *x;
 841         int ret;
 842
 843         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
 844         for (x = h->attrs; x < h->attrs + h->length; x++) {
 845                 if (!x->name)
 846                         continue;
 847
 848                 ret = func(x->name, x->value, x->value_len, data);
 849                 if (ret & XATTR_CHANGED)
 850                         h->dirty = 1;
 851                 if (ret & XATTR_ABORT)
 852                         return 0;
 853         }
 854
 855         return 0;
 856 }
 857
 858 errcode_t ext2fs_xattr_get(struct ext2_xattr_handle *h, const char *key,
 859                            void **value, size_t *value_len)
 860 {
 861         struct ext2_xattr *x;
 862         void *val;
 863         errcode_t err;
 864
 865         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
 866         for (x = h->attrs; x < h->attrs + h->length; x++) {
 867                 if (!x->name)
 868                         continue;
 869
 870                 if (strcmp(x->name, key) == 0) {
 871                         err = ext2fs_get_mem(x->value_len, &val);
 872                         if (err)
 873                                 return err;
 874                         memcpy(val, x->value, x->value_len);
 875                         *value = val;
 876                         *value_len = x->value_len;
 877                         return 0;
 878                 }
 879         }
 880
 881         return EXT2_ET_EA_KEY_NOT_FOUND;
 882 }
 883
 884 errcode_t ext2fs_xattr_inode_max_size(ext2_filsys fs, ext2_ino_t ino,
 885                                       size_t *size)
 886 {
 887         struct ext2_ext_attr_entry *entry;
 888         struct ext2_inode_large *inode;
 889         __u32 ea_inode_magic;
 890         unsigned int minoff;
 891         void *start;
 892         int i;
 893         errcode_t err;
 894
 895         i = EXT2_INODE_SIZE(fs->super);
 896         if (i < sizeof(*inode))
 897                 i = sizeof(*inode);
 898         err = ext2fs_get_memzero(i, &inode);
 899         if (err)
 900                 return err;
 901
 902         err = ext2fs_read_inode_full(fs, ino, (struct ext2_inode *)inode,
 903                                      EXT2_INODE_SIZE(fs->super));
 904         if (err)
 905                 goto out;
 906
 907         /* Does the inode have size for EA? */
 908         if (EXT2_INODE_SIZE(fs->super) <= EXT2_GOOD_OLD_INODE_SIZE +
 909                                                   inode->i_extra_isize +
 910                                                   sizeof(__u32)) {
 911                 err = EXT2_ET_INLINE_DATA_NO_SPACE;
 912                 goto out;
 913         }
 914
 915         minoff = EXT2_INODE_SIZE(fs->super) - sizeof(*inode) - sizeof(__u32);
 916         memcpy(&ea_inode_magic, ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 917                inode->i_extra_isize, sizeof(__u32));
 918         if (ea_inode_magic == EXT2_EXT_ATTR_MAGIC) {
 919                 /* has xattrs.  calculate the size */
 920                 start= ((char *) inode) + EXT2_GOOD_OLD_INODE_SIZE +
 921                         inode->i_extra_isize + sizeof(__u32);
 922                 entry = start;
 923                 while (!EXT2_EXT_IS_LAST_ENTRY(entry)) {
 924                         if (!entry->e_value_block && entry->e_value_size) {
 925                                 unsigned int offs = entry->e_value_offs;
 926                                 if (offs < minoff)
 927                                         minoff = offs;
 928                         }
 929                         entry = EXT2_EXT_ATTR_NEXT(entry);
 930                 }
 931                 *size = minoff - ((char *)entry - (char *)start) - sizeof(__u32);
 932         } else {
 933                 /* no xattr.  return a maximum size */
 934                 *size = EXT2_EXT_ATTR_SIZE(minoff -
 935                                            EXT2_EXT_ATTR_LEN(strlen("data")) -
 936                                            EXT2_EXT_ATTR_ROUND - sizeof(__u32));
 937         }
 938
 939 out:
 940         ext2fs_free_mem(&inode);
 941         return err;
 942 }
 943
 944 errcode_t ext2fs_xattr_set(struct ext2_xattr_handle *handle,
 945                            const char *key,
 946                            const void *value,
 947                            size_t value_len)
 948 {
 949         struct ext2_xattr *x, *last_empty;
 950         char *new_value;
 951         errcode_t err;
 952
 953         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
 954         last_empty = NULL;
 955         for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
 956                 if (!x->name) {
 957                         last_empty = x;
 958                         continue;
 959                 }
 960
 961                 /* Replace xattr */
 962                 if (strcmp(x->name, key) == 0) {
 963                         err = ext2fs_get_mem(value_len, &new_value);
 964                         if (err)
 965                                 return err;
 966                         memcpy(new_value, value, value_len);
 967                         ext2fs_free_mem(&x->value);
 968                         x->value = new_value;
 969                         x->value_len = value_len;
 970                         handle->dirty = 1;
 971                         return 0;
 972                 }
 973         }
 974
 975         /* Add attr to empty slot */
 976         if (last_empty) {
 977                 err = ext2fs_get_mem(strlen(key) + 1, &last_empty->name);
 978                 if (err)
 979                         return err;
 980                 strcpy(last_empty->name, key);
 981
 982                 err = ext2fs_get_mem(value_len, &last_empty->value);
 983                 if (err)
 984                         return err;
 985                 memcpy(last_empty->value, value, value_len);
 986                 last_empty->value_len = value_len;
 987                 handle->dirty = 1;
 988                 handle->count++;
 989                 return 0;
 990         }
 991
 992         /* Expand array, append slot */
 993         err = ext2fs_xattrs_expand(handle, 4);
 994         if (err)
 995                 return err;
 996
 997         x = handle->attrs + handle->length - 4;
 998         err = ext2fs_get_mem(strlen(key) + 1, &x->name);
 999         if (err)
1000                 return err;
1001         strcpy(x->name, key);
1002
1003         err = ext2fs_get_mem(value_len, &x->value);
1004         if (err)
1005                 return err;
1006         memcpy(x->value, value, value_len);
1007         x->value_len = value_len;
1008         handle->dirty = 1;
1009         handle->count++;
1010         return 0;
1011 }
1012
1013 errcode_t ext2fs_xattr_remove(struct ext2_xattr_handle *handle,
1014                               const char *key)
1015 {
1016         struct ext2_xattr *x;
1017
1018         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
1019         for (x = handle->attrs; x < handle->attrs + handle->length; x++) {
1020                 if (!x->name)
1021                         continue;
1022
1023                 if (strcmp(x->name, key) == 0) {
1024                         ext2fs_free_mem(&x->name);
1025                         ext2fs_free_mem(&x->value);
1026                         x->value_len = 0;
1027                         handle->dirty = 1;
1028                         handle->count--;
1029                         return 0;
1030                 }
1031         }
1032
1033         /* no key found, success! */
1034         return 0;
1035 }
1036
1037 errcode_t ext2fs_xattrs_open(ext2_filsys fs, ext2_ino_t ino,
1038                              struct ext2_xattr_handle **handle)
1039 {
1040         struct ext2_xattr_handle *h;
1041         errcode_t err;
1042
1043         if (!EXT2_HAS_COMPAT_FEATURE(fs->super,
1044                                      EXT2_FEATURE_COMPAT_EXT_ATTR) &&
1045             !EXT2_HAS_INCOMPAT_FEATURE(fs->super,
1046                                      EXT4_FEATURE_INCOMPAT_INLINE_DATA))
1047                 return EXT2_ET_MISSING_EA_FEATURE;
1048
1049         err = ext2fs_get_memzero(sizeof(*h), &h);
1050         if (err)
1051                 return err;
1052
1053         h->magic = EXT2_ET_MAGIC_EA_HANDLE;
1054         h->length = 4;
1055         err = ext2fs_get_arrayzero(h->length, sizeof(struct ext2_xattr),
1056                                    &h->attrs);
1057         if (err) {
1058                 ext2fs_free_mem(&h);
1059                 return err;
1060         }
1061         h->count = 0;
1062         h->ino = ino;
1063         h->fs = fs;
1064         *handle = h;
1065         return 0;
1066 }
1067
1068 errcode_t ext2fs_xattrs_close(struct ext2_xattr_handle **handle)
1069 {
1070         struct ext2_xattr_handle *h = *handle;
1071         errcode_t err;
1072
1073         EXT2_CHECK_MAGIC(h, EXT2_ET_MAGIC_EA_HANDLE);
1074         if (h->dirty) {
1075                 err = ext2fs_xattrs_write(h);
1076                 if (err)
1077                         return err;
1078         }
1079
1080         xattrs_free_keys(h);
1081         ext2fs_free_mem(&h->attrs);
1082         ext2fs_free_mem(handle);
1083         return 0;
1084 }
1085
1086 errcode_t ext2fs_xattrs_count(struct ext2_xattr_handle *handle, size_t *count)
1087 {
1088         EXT2_CHECK_MAGIC(handle, EXT2_ET_MAGIC_EA_HANDLE);
1089         *count = handle->count;
1090         return 0;
1091 }