libexfat/node.c

   1 /*
   2         node.c (09.10.09)
   3         exFAT file system implementation library.
   4
   5         Free exFAT implementation.
   6         Copyright (C) 2010-2015  Andrew Nayenko
   7
   8         This program is free software; you can redistribute it and/or modify
   9         it under the terms of the GNU General Public License as published by
  10         the Free Software Foundation, either version 2 of the License, or
  11         (at your option) any later version.
  12
  13         This program is distributed in the hope that it will be useful,
  14         but WITHOUT ANY WARRANTY; without even the implied warranty of
  15         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16         GNU General Public License for more details.
  17
  18         You should have received a copy of the GNU General Public License along
  19         with this program; if not, write to the Free Software Foundation, Inc.,
  20         51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21 */
  22
  23 #include "exfat.h"
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <inttypes.h>
  27
  28 /* on-disk nodes iterator */
  29 struct iterator
  30 {
  31         cluster_t cluster;
  32         off_t offset;
  33         int contiguous;
  34         char* chunk;
  35 };
  36
  37 struct exfat_node* exfat_get_node(struct exfat_node* node)
  38 {
  39         /* if we switch to multi-threaded mode we will need atomic
  40            increment here and atomic decrement in exfat_put_node() */
  41         node->references++;
  42         return node;
  43 }
  44
  45 void exfat_put_node(struct exfat* ef, struct exfat_node* node)
  46 {
  47         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
  48
  49         --node->references;
  50         if (node->references < 0)
  51         {
  52                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
  53                 exfat_bug("reference counter of '%s' is below zero", buffer);
  54         }
  55         else if (node->references == 0 && node != ef->root)
  56         {
  57                 if (node->flags & EXFAT_ATTRIB_DIRTY)
  58                 {
  59                         exfat_get_name(node, buffer, sizeof(buffer) - 1);
  60                         exfat_warn("dirty node '%s' with zero references", buffer);
  61                 }
  62         }
  63 }
  64
  65 /**
  66  * This function must be called on rmdir and unlink (after the last
  67  * exfat_put_node()) to free clusters.
  68  */
  69 int exfat_cleanup_node(struct exfat* ef, struct exfat_node* node)
  70 {
  71         int rc = 0;
  72
  73         if (node->references != 0)
  74                 exfat_bug("unable to cleanup a node with %d references",
  75                                 node->references);
  76
  77         if (node->flags & EXFAT_ATTRIB_UNLINKED)
  78         {
  79                 /* free all clusters and node structure itself */
  80                 rc = exfat_truncate(ef, node, 0, true);
  81                 /* free the node even in case of error or its memory will be lost */
  82                 free(node);
  83         }
  84         return rc;
  85 }
  86
  87 /**
  88  * Cluster + offset from the beginning of the directory to absolute offset.
  89  */
  90 static off_t co2o(struct exfat* ef, cluster_t cluster, off_t offset)
  91 {
  92         return exfat_c2o(ef, cluster) + offset % CLUSTER_SIZE(*ef->sb);
  93 }
  94
  95 static int opendir(struct exfat* ef, const struct exfat_node* dir,
  96                 struct iterator* it)
  97 {
  98         if (!(dir->flags & EXFAT_ATTRIB_DIR))
  99                 exfat_bug("not a directory");
 100         it->cluster = dir->start_cluster;
 101         it->offset = 0;
 102         it->contiguous = IS_CONTIGUOUS(*dir);
 103         it->chunk = malloc(CLUSTER_SIZE(*ef->sb));
 104         if (it->chunk == NULL)
 105         {
 106                 exfat_error("out of memory");
 107                 return -ENOMEM;
 108         }
 109         if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 110                         exfat_c2o(ef, it->cluster)) < 0)
 111         {
 112                 exfat_error("failed to read directory cluster %#x", it->cluster);
 113                 return -EIO;
 114         }
 115         return 0;
 116 }
 117
 118 static void closedir(struct iterator* it)
 119 {
 120         it->cluster = 0;
 121         it->offset = 0;
 122         it->contiguous = 0;
 123         free(it->chunk);
 124         it->chunk = NULL;
 125 }
 126
 127 static bool fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 128                 struct iterator* it)
 129 {
 130         /* move iterator to the next entry in the directory */
 131         it->offset += sizeof(struct exfat_entry);
 132         /* fetch the next cluster if needed */
 133         if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
 134         {
 135                 /* reached the end of directory; the caller should check this
 136                    condition too */
 137                 if (it->offset >= parent->size)
 138                         return true;
 139                 it->cluster = exfat_next_cluster(ef, parent, it->cluster);
 140                 if (CLUSTER_INVALID(it->cluster))
 141                 {
 142                         exfat_error("invalid cluster 0x%x while reading directory",
 143                                         it->cluster);
 144                         return false;
 145                 }
 146                 if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 147                                 exfat_c2o(ef, it->cluster)) < 0)
 148                 {
 149                         exfat_error("failed to read the next directory cluster %#x",
 150                                         it->cluster);
 151                         return false;
 152                 }
 153         }
 154         return true;
 155 }
 156
 157 static struct exfat_node* allocate_node(void)
 158 {
 159         struct exfat_node* node = malloc(sizeof(struct exfat_node));
 160         if (node == NULL)
 161         {
 162                 exfat_error("failed to allocate node");
 163                 return NULL;
 164         }
 165         memset(node, 0, sizeof(struct exfat_node));
 166         return node;
 167 }
 168
 169 static void init_node_meta1(struct exfat_node* node,
 170                 const struct exfat_entry_meta1* meta1)
 171 {
 172         node->flags = le16_to_cpu(meta1->attrib);
 173         node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
 174                         meta1->mtime_cs);
 175         /* there is no centiseconds field for atime */
 176         node->atime = exfat_exfat2unix(meta1->adate, meta1->atime, 0);
 177 }
 178
 179 static void init_node_meta2(struct exfat_node* node,
 180                 const struct exfat_entry_meta2* meta2)
 181 {
 182         node->size = le64_to_cpu(meta2->size);
 183         node->start_cluster = le32_to_cpu(meta2->start_cluster);
 184         node->fptr_cluster = node->start_cluster;
 185         if (meta2->flags & EXFAT_FLAG_CONTIGUOUS)
 186                 node->flags |= EXFAT_ATTRIB_CONTIGUOUS;
 187 }
 188
 189 static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
 190                 const struct iterator* it)
 191 {
 192         return (const struct exfat_entry*)
 193                         (it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
 194 }
 195
 196 static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
 197                 uint16_t reference_checksum, uint64_t valid_size)
 198 {
 199         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 200
 201         /*
 202            Validate checksum first. If it's invalid all other fields probably
 203            contain just garbage.
 204         */
 205         if (actual_checksum != reference_checksum)
 206         {
 207                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 208                 exfat_error("'%s' has invalid checksum (%#hx != %#hx)", buffer,
 209                                 actual_checksum, reference_checksum);
 210                 return false;
 211         }
 212
 213         /*
 214            exFAT does not support sparse files but allows files with uninitialized
 215            clusters. For such files valid_size means initialized data size and
 216            cannot be greater than file size. See SetFileValidData() function
 217            description in MSDN.
 218         */
 219         if (valid_size > node->size)
 220         {
 221                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 222                 exfat_error("'%s' has valid size (%"PRIu64") greater than size "
 223                                 "(%"PRIu64")", buffer, valid_size, node->size);
 224                 return false;
 225         }
 226
 227         return true;
 228 }
 229
 230 /*
 231  * Reads one entry in directory at position pointed by iterator and fills
 232  * node structure.
 233  */
 234 static int readdir(struct exfat* ef, const struct exfat_node* parent,
 235                 struct exfat_node** node, struct iterator* it)
 236 {
 237         int rc = -EIO;
 238         const struct exfat_entry* entry;
 239         const struct exfat_entry_meta1* meta1;
 240         const struct exfat_entry_meta2* meta2;
 241         const struct exfat_entry_name* file_name;
 242         const struct exfat_entry_upcase* upcase;
 243         const struct exfat_entry_bitmap* bitmap;
 244         const struct exfat_entry_label* label;
 245         uint8_t continuations = 0;
 246         le16_t* namep = NULL;
 247         uint16_t reference_checksum = 0;
 248         uint16_t actual_checksum = 0;
 249         uint64_t valid_size = 0;
 250
 251         *node = NULL;
 252
 253         for (;;)
 254         {
 255                 if (it->offset >= parent->size)
 256                 {
 257                         if (continuations != 0)
 258                         {
 259                                 exfat_error("expected %hhu continuations", continuations);
 260                                 goto error;
 261                         }
 262                         return -ENOENT; /* that's OK, means end of directory */
 263                 }
 264
 265                 entry = get_entry_ptr(ef, it);
 266                 switch (entry->type)
 267                 {
 268                 case EXFAT_ENTRY_FILE:
 269                         if (continuations != 0)
 270                         {
 271                                 exfat_error("expected %hhu continuations before new entry",
 272                                                 continuations);
 273                                 goto error;
 274                         }
 275                         meta1 = (const struct exfat_entry_meta1*) entry;
 276                         continuations = meta1->continuations;
 277                         /* each file entry must have at least 2 continuations:
 278                            info and name */
 279                         if (continuations < 2)
 280                         {
 281                                 exfat_error("too few continuations (%hhu)", continuations);
 282                                 goto error;
 283                         }
 284                         if (continuations > 1 +
 285                                         DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
 286                         {
 287                                 exfat_error("too many continuations (%hhu)", continuations);
 288                                 goto error;
 289                         }
 290                         reference_checksum = le16_to_cpu(meta1->checksum);
 291                         actual_checksum = exfat_start_checksum(meta1);
 292                         *node = allocate_node();
 293                         if (*node == NULL)
 294                         {
 295                                 rc = -ENOMEM;
 296                                 goto error;
 297                         }
 298                         /* new node has zero reference counter */
 299                         (*node)->entry_cluster = it->cluster;
 300                         (*node)->entry_offset = it->offset;
 301                         init_node_meta1(*node, meta1);
 302                         namep = (*node)->name;
 303                         break;
 304
 305                 case EXFAT_ENTRY_FILE_INFO:
 306                         if (continuations < 2)
 307                         {
 308                                 exfat_error("unexpected continuation (%hhu)",
 309                                                 continuations);
 310                                 goto error;
 311                         }
 312                         meta2 = (const struct exfat_entry_meta2*) entry;
 313                         if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
 314                         {
 315                                 exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
 316                                 goto error;
 317                         }
 318                         init_node_meta2(*node, meta2);
 319                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 320                         valid_size = le64_to_cpu(meta2->valid_size);
 321                         /* empty files must be marked as non-contiguous */
 322                         if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
 323                         {
 324                                 exfat_error("empty file marked as contiguous (0x%hhx)",
 325                                                 meta2->flags);
 326                                 goto error;
 327                         }
 328                         /* directories must be aligned on at cluster boundary */
 329                         if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
 330                                 (*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
 331                         {
 332                                 exfat_error("directory has invalid size %"PRIu64" bytes",
 333                                                 (*node)->size);
 334                                 goto error;
 335                         }
 336                         --continuations;
 337                         break;
 338
 339                 case EXFAT_ENTRY_FILE_NAME:
 340                         if (continuations == 0)
 341                         {
 342                                 exfat_error("unexpected continuation");
 343                                 goto error;
 344                         }
 345                         file_name = (const struct exfat_entry_name*) entry;
 346                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 347
 348                         memcpy(namep, file_name->name,
 349                                         MIN(EXFAT_ENAME_MAX,
 350                                                 ((*node)->name + EXFAT_NAME_MAX - namep)) *
 351                                         sizeof(le16_t));
 352                         namep += EXFAT_ENAME_MAX;
 353                         if (--continuations == 0)
 354                         {
 355                                 if (!check_node(*node, actual_checksum, reference_checksum,
 356                                                 valid_size))
 357                                         goto error;
 358                                 if (!fetch_next_entry(ef, parent, it))
 359                                         goto error;
 360                                 return 0; /* entry completed */
 361                         }
 362                         break;
 363
 364                 case EXFAT_ENTRY_UPCASE:
 365                         if (ef->upcase != NULL)
 366                                 break;
 367                         upcase = (const struct exfat_entry_upcase*) entry;
 368                         if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
 369                         {
 370                                 exfat_error("invalid cluster 0x%x in upcase table",
 371                                                 le32_to_cpu(upcase->start_cluster));
 372                                 goto error;
 373                         }
 374                         if (le64_to_cpu(upcase->size) == 0 ||
 375                                 le64_to_cpu(upcase->size) > 0xffff * sizeof(uint16_t) ||
 376                                 le64_to_cpu(upcase->size) % sizeof(uint16_t) != 0)
 377                         {
 378                                 exfat_error("bad upcase table size (%"PRIu64" bytes)",
 379                                                 le64_to_cpu(upcase->size));
 380                                 goto error;
 381                         }
 382                         ef->upcase = malloc(le64_to_cpu(upcase->size));
 383                         if (ef->upcase == NULL)
 384                         {
 385                                 exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
 386                                                 le64_to_cpu(upcase->size));
 387                                 rc = -ENOMEM;
 388                                 goto error;
 389                         }
 390                         ef->upcase_chars = le64_to_cpu(upcase->size) / sizeof(le16_t);
 391
 392                         if (exfat_pread(ef->dev, ef->upcase, le64_to_cpu(upcase->size),
 393                                         exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 394                         {
 395                                 exfat_error("failed to read upper case table "
 396                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 397                                                 le64_to_cpu(upcase->size),
 398                                                 le32_to_cpu(upcase->start_cluster));
 399                                 goto error;
 400                         }
 401                         break;
 402
 403                 case EXFAT_ENTRY_BITMAP:
 404                         bitmap = (const struct exfat_entry_bitmap*) entry;
 405                         ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
 406                         if (CLUSTER_INVALID(ef->cmap.start_cluster))
 407                         {
 408                                 exfat_error("invalid cluster 0x%x in clusters bitmap",
 409                                                 ef->cmap.start_cluster);
 410                                 goto error;
 411                         }
 412                         ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 413                                 EXFAT_FIRST_DATA_CLUSTER;
 414                         if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 415                         {
 416                                 exfat_error("invalid clusters bitmap size: %"PRIu64
 417                                                 " (expected at least %u)",
 418                                                 le64_to_cpu(bitmap->size),
 419                                                 DIV_ROUND_UP(ef->cmap.size, 8));
 420                                 goto error;
 421                         }
 422                         /* FIXME bitmap can be rather big, up to 512 MB */
 423                         ef->cmap.chunk_size = ef->cmap.size;
 424                         ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 425                         if (ef->cmap.chunk == NULL)
 426                         {
 427                                 exfat_error("failed to allocate clusters bitmap chunk "
 428                                                 "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
 429                                 rc = -ENOMEM;
 430                                 goto error;
 431                         }
 432
 433                         if (exfat_pread(ef->dev, ef->cmap.chunk,
 434                                         BMAP_SIZE(ef->cmap.chunk_size),
 435                                         exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
 436                         {
 437                                 exfat_error("failed to read clusters bitmap "
 438                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 439                                                 le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
 440                                 goto error;
 441                         }
 442                         break;
 443
 444                 case EXFAT_ENTRY_LABEL:
 445                         label = (const struct exfat_entry_label*) entry;
 446                         if (label->length > EXFAT_ENAME_MAX)
 447                         {
 448                                 exfat_error("too long label (%hhu chars)", label->length);
 449                                 goto error;
 450                         }
 451                         if (utf16_to_utf8(ef->label, label->name,
 452                                                 sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
 453                                 goto error;
 454                         break;
 455
 456                 default:
 457                         if (!(entry->type & EXFAT_ENTRY_VALID))
 458                                 break; /* deleted entry, ignore it */
 459                         if (!(entry->type & EXFAT_ENTRY_OPTIONAL))
 460                         {
 461                                 exfat_error("unknown entry type %#hhx", entry->type);
 462                                 goto error;
 463                         }
 464                         /* optional entry, warn and skip */
 465                         exfat_warn("unknown entry type %#hhx", entry->type);
 466                         if (continuations == 0)
 467                         {
 468                                 exfat_error("unexpected continuation");
 469                                 goto error;
 470                         }
 471                         --continuations;
 472                         break;
 473                 }
 474
 475                 if (!fetch_next_entry(ef, parent, it))
 476                         goto error;
 477         }
 478         /* we never reach here */
 479
 480 error:
 481         free(*node);
 482         *node = NULL;
 483         return rc;
 484 }
 485
 486 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 487 {
 488         struct iterator it;
 489         int rc;
 490         struct exfat_node* node;
 491         struct exfat_node* current = NULL;
 492
 493         if (dir->flags & EXFAT_ATTRIB_CACHED)
 494                 return 0; /* already cached */
 495
 496         rc = opendir(ef, dir, &it);
 497         if (rc != 0)
 498                 return rc;
 499         while ((rc = readdir(ef, dir, &node, &it)) == 0)
 500         {
 501                 node->parent = dir;
 502                 if (current != NULL)
 503                 {
 504                         current->next = node;
 505                         node->prev = current;
 506                 }
 507                 else
 508                         dir->child = node;
 509
 510                 current = node;
 511         }
 512         closedir(&it);
 513
 514         if (rc != -ENOENT)
 515         {
 516                 /* rollback */
 517                 for (current = dir->child; current; current = node)
 518                 {
 519                         node = current->next;
 520                         free(current);
 521                 }
 522                 dir->child = NULL;
 523                 return rc;
 524         }
 525
 526         dir->flags |= EXFAT_ATTRIB_CACHED;
 527         return 0;
 528 }
 529
 530 static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
 531 {
 532         node->parent = dir;
 533         if (dir->child)
 534         {
 535                 dir->child->prev = node;
 536                 node->next = dir->child;
 537         }
 538         dir->child = node;
 539 }
 540
 541 static void tree_detach(struct exfat_node* node)
 542 {
 543         if (node->prev)
 544                 node->prev->next = node->next;
 545         else /* this is the first node in the list */
 546                 node->parent->child = node->next;
 547         if (node->next)
 548                 node->next->prev = node->prev;
 549         node->parent = NULL;
 550         node->prev = NULL;
 551         node->next = NULL;
 552 }
 553
 554 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 555 {
 556         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 557
 558         while (node->child)
 559         {
 560                 struct exfat_node* p = node->child;
 561                 reset_cache(ef, p);
 562                 tree_detach(p);
 563                 free(p);
 564         }
 565         node->flags &= ~EXFAT_ATTRIB_CACHED;
 566         if (node->references != 0)
 567         {
 568                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 569                 exfat_warn("non-zero reference counter (%d) for '%s'",
 570                                 node->references, buffer);
 571         }
 572         if (node != ef->root && (node->flags & EXFAT_ATTRIB_DIRTY))
 573         {
 574                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 575                 exfat_bug("node '%s' is dirty", buffer);
 576         }
 577         while (node->references)
 578                 exfat_put_node(ef, node);
 579 }
 580
 581 void exfat_reset_cache(struct exfat* ef)
 582 {
 583         reset_cache(ef, ef->root);
 584 }
 585
 586 static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 587                 cluster_t* cluster, off_t* offset)
 588 {
 589         *offset += sizeof(struct exfat_entry);
 590         if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
 591         {
 592                 *cluster = exfat_next_cluster(ef, parent, *cluster);
 593                 if (CLUSTER_INVALID(*cluster))
 594                 {
 595                         exfat_error("invalid cluster %#x while getting next entry",
 596                                         *cluster);
 597                         return false;
 598                 }
 599         }
 600         return true;
 601 }
 602
 603 int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 604 {
 605         cluster_t cluster;
 606         off_t offset;
 607         off_t meta1_offset, meta2_offset;
 608         struct exfat_entry_meta1 meta1;
 609         struct exfat_entry_meta2 meta2;
 610
 611         if (!(node->flags & EXFAT_ATTRIB_DIRTY))
 612                 return 0; /* no need to flush */
 613
 614         if (ef->ro)
 615                 exfat_bug("unable to flush node to read-only FS");
 616
 617         if (node->parent == NULL)
 618                 return 0; /* do not flush unlinked node */
 619
 620         cluster = node->entry_cluster;
 621         offset = node->entry_offset;
 622         meta1_offset = co2o(ef, cluster, offset);
 623         if (!next_entry(ef, node->parent, &cluster, &offset))
 624                 return -EIO;
 625         meta2_offset = co2o(ef, cluster, offset);
 626
 627         if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 628         {
 629                 exfat_error("failed to read meta1 entry on flush");
 630                 return -EIO;
 631         }
 632         if (meta1.type != EXFAT_ENTRY_FILE)
 633                 exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
 634         meta1.attrib = cpu_to_le16(node->flags);
 635         exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 636         exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 637
 638         if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 639         {
 640                 exfat_error("failed to read meta2 entry on flush");
 641                 return -EIO;
 642         }
 643         if (meta2.type != EXFAT_ENTRY_FILE_INFO)
 644                 exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
 645         meta2.size = meta2.valid_size = cpu_to_le64(node->size);
 646         meta2.start_cluster = cpu_to_le32(node->start_cluster);
 647         meta2.flags = EXFAT_FLAG_ALWAYS1;
 648         /* empty files must not be marked as contiguous */
 649         if (node->size != 0 && IS_CONTIGUOUS(*node))
 650                 meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 651         /* name hash remains unchanged, no need to recalculate it */
 652
 653         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 654
 655         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 656         {
 657                 exfat_error("failed to write meta1 entry on flush");
 658                 return -EIO;
 659         }
 660         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 661         {
 662                 exfat_error("failed to write meta2 entry on flush");
 663                 return -EIO;
 664         }
 665
 666         node->flags &= ~EXFAT_ATTRIB_DIRTY;
 667         return 0;
 668 }
 669
 670 static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 671 {
 672         cluster_t cluster = node->entry_cluster;
 673         off_t offset = node->entry_offset;
 674         int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
 675         uint8_t entry_type;
 676
 677         entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
 678         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 679         {
 680                 exfat_error("failed to erase meta1 entry");
 681                 return false;
 682         }
 683
 684         if (!next_entry(ef, node->parent, &cluster, &offset))
 685                 return false;
 686         entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
 687         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 688         {
 689                 exfat_error("failed to erase meta2 entry");
 690                 return false;
 691         }
 692
 693         while (name_entries--)
 694         {
 695                 if (!next_entry(ef, node->parent, &cluster, &offset))
 696                         return false;
 697                 entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
 698                 if (exfat_pwrite(ef->dev, &entry_type, 1,
 699                                 co2o(ef, cluster, offset)) < 0)
 700                 {
 701                         exfat_error("failed to erase name entry");
 702                         return false;
 703                 }
 704         }
 705         return true;
 706 }
 707
 708 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 709                 off_t deleted_offset)
 710 {
 711         const struct exfat_node* node;
 712         const struct exfat_node* last_node;
 713         uint64_t entries = 0;
 714         uint64_t new_size;
 715
 716         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 717                 exfat_bug("attempted to shrink a file");
 718         if (!(dir->flags & EXFAT_ATTRIB_CACHED))
 719                 exfat_bug("attempted to shrink uncached directory");
 720
 721         for (last_node = node = dir->child; node; node = node->next)
 722         {
 723                 if (deleted_offset < node->entry_offset)
 724                 {
 725                         /* there are other entries after the removed one, no way to shrink
 726                            this directory */
 727                         return 0;
 728                 }
 729                 if (last_node->entry_offset < node->entry_offset)
 730                         last_node = node;
 731         }
 732
 733         if (last_node)
 734         {
 735                 /* offset of the last entry */
 736                 entries += last_node->entry_offset / sizeof(struct exfat_entry);
 737                 /* two subentries with meta info */
 738                 entries += 2;
 739                 /* subentries with file name */
 740                 entries += DIV_ROUND_UP(utf16_length(last_node->name),
 741                                 EXFAT_ENAME_MAX);
 742         }
 743
 744         new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
 745                                  CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
 746         if (new_size == 0) /* directory always has at least 1 cluster */
 747                 new_size = CLUSTER_SIZE(*ef->sb);
 748         if (new_size == dir->size)
 749                 return 0;
 750         return exfat_truncate(ef, dir, new_size, true);
 751 }
 752
 753 static int delete(struct exfat* ef, struct exfat_node* node)
 754 {
 755         struct exfat_node* parent = node->parent;
 756         off_t deleted_offset = node->entry_offset;
 757         int rc;
 758
 759         exfat_get_node(parent);
 760         if (!erase_entry(ef, node))
 761         {
 762                 exfat_put_node(ef, parent);
 763                 return -EIO;
 764         }
 765         exfat_update_mtime(parent);
 766         tree_detach(node);
 767         rc = shrink_directory(ef, parent, deleted_offset);
 768         node->flags |= EXFAT_ATTRIB_UNLINKED;
 769         if (rc != 0)
 770         {
 771                 exfat_flush_node(ef, parent);
 772                 exfat_put_node(ef, parent);
 773                 return rc;
 774         }
 775         rc = exfat_flush_node(ef, parent);
 776         exfat_put_node(ef, parent);
 777         return rc;
 778 }
 779
 780 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 781 {
 782         if (node->flags & EXFAT_ATTRIB_DIR)
 783                 return -EISDIR;
 784         return delete(ef, node);
 785 }
 786
 787 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 788 {
 789         int rc;
 790
 791         if (!(node->flags & EXFAT_ATTRIB_DIR))
 792                 return -ENOTDIR;
 793         /* check that directory is empty */
 794         rc = exfat_cache_directory(ef, node);
 795         if (rc != 0)
 796                 return rc;
 797         if (node->child)
 798                 return -ENOTEMPTY;
 799         return delete(ef, node);
 800 }
 801
 802 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 803                 uint64_t asize, uint32_t difference)
 804 {
 805         return exfat_truncate(ef, dir,
 806                         DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
 807                                 * CLUSTER_SIZE(*ef->sb), true);
 808 }
 809
 810 static int find_slot(struct exfat* ef, struct exfat_node* dir,
 811                 cluster_t* cluster, off_t* offset, int subentries)
 812 {
 813         struct iterator it;
 814         int rc;
 815         const struct exfat_entry* entry;
 816         int contiguous = 0;
 817
 818         rc = opendir(ef, dir, &it);
 819         if (rc != 0)
 820                 return rc;
 821         for (;;)
 822         {
 823                 if (contiguous == 0)
 824                 {
 825                         *cluster = it.cluster;
 826                         *offset = it.offset;
 827                 }
 828                 entry = get_entry_ptr(ef, &it);
 829                 if (entry->type & EXFAT_ENTRY_VALID)
 830                         contiguous = 0;
 831                 else
 832                         contiguous++;
 833                 if (contiguous == subentries)
 834                         break;  /* suitable slot is found */
 835                 if (it.offset + sizeof(struct exfat_entry) >= dir->size)
 836                 {
 837                         rc = grow_directory(ef, dir, dir->size,
 838                                         (subentries - contiguous) * sizeof(struct exfat_entry));
 839                         if (rc != 0)
 840                         {
 841                                 closedir(&it);
 842                                 return rc;
 843                         }
 844                 }
 845                 if (!fetch_next_entry(ef, dir, &it))
 846                 {
 847                         closedir(&it);
 848                         return -EIO;
 849                 }
 850         }
 851         closedir(&it);
 852         return 0;
 853 }
 854
 855 static int write_entry(struct exfat* ef, struct exfat_node* dir,
 856                 const le16_t* name, cluster_t cluster, off_t offset, uint16_t attrib)
 857 {
 858         struct exfat_node* node;
 859         struct exfat_entry_meta1 meta1;
 860         struct exfat_entry_meta2 meta2;
 861         const size_t name_length = utf16_length(name);
 862         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 863         int i;
 864
 865         node = allocate_node();
 866         if (node == NULL)
 867                 return -ENOMEM;
 868         node->entry_cluster = cluster;
 869         node->entry_offset = offset;
 870         memcpy(node->name, name, name_length * sizeof(le16_t));
 871
 872         memset(&meta1, 0, sizeof(meta1));
 873         meta1.type = EXFAT_ENTRY_FILE;
 874         meta1.continuations = 1 + name_entries;
 875         meta1.attrib = cpu_to_le16(attrib);
 876         exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
 877                         &meta1.crtime_cs);
 878         meta1.adate = meta1.mdate = meta1.crdate;
 879         meta1.atime = meta1.mtime = meta1.crtime;
 880         meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 881
 882         memset(&meta2, 0, sizeof(meta2));
 883         meta2.type = EXFAT_ENTRY_FILE_INFO;
 884         meta2.flags = EXFAT_FLAG_ALWAYS1;
 885         meta2.name_length = name_length;
 886         meta2.name_hash = exfat_calc_name_hash(ef, node->name);
 887         meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
 888
 889         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 890
 891         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 892                         co2o(ef, cluster, offset)) < 0)
 893         {
 894                 exfat_error("failed to write meta1 entry");
 895                 return -EIO;
 896         }
 897         if (!next_entry(ef, dir, &cluster, &offset))
 898                 return -EIO;
 899         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 900                         co2o(ef, cluster, offset)) < 0)
 901         {
 902                 exfat_error("failed to write meta2 entry");
 903                 return -EIO;
 904         }
 905         for (i = 0; i < name_entries; i++)
 906         {
 907                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 908                 memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
 909                                 MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
 910                                 sizeof(le16_t));
 911                 if (!next_entry(ef, dir, &cluster, &offset))
 912                         return -EIO;
 913                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 914                                 co2o(ef, cluster, offset)) < 0)
 915                 {
 916                         exfat_error("failed to write name entry");
 917                         return -EIO;
 918                 }
 919         }
 920
 921         init_node_meta1(node, &meta1);
 922         init_node_meta2(node, &meta2);
 923
 924         tree_attach(dir, node);
 925         exfat_update_mtime(dir);
 926         return 0;
 927 }
 928
 929 static int create(struct exfat* ef, const char* path, uint16_t attrib)
 930 {
 931         struct exfat_node* dir;
 932         struct exfat_node* existing;
 933         cluster_t cluster = EXFAT_CLUSTER_BAD;
 934         off_t offset = -1;
 935         le16_t name[EXFAT_NAME_MAX + 1];
 936         int rc;
 937
 938         rc = exfat_split(ef, &dir, &existing, name, path);
 939         if (rc != 0)
 940                 return rc;
 941         if (existing != NULL)
 942         {
 943                 exfat_put_node(ef, existing);
 944                 exfat_put_node(ef, dir);
 945                 return -EEXIST;
 946         }
 947
 948         rc = find_slot(ef, dir, &cluster, &offset,
 949                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
 950         if (rc != 0)
 951         {
 952                 exfat_put_node(ef, dir);
 953                 return rc;
 954         }
 955         rc = write_entry(ef, dir, name, cluster, offset, attrib);
 956         if (rc != 0)
 957         {
 958                 exfat_put_node(ef, dir);
 959                 return rc;
 960         }
 961         rc = exfat_flush_node(ef, dir);
 962         exfat_put_node(ef, dir);
 963         return rc;
 964 }
 965
 966 int exfat_mknod(struct exfat* ef, const char* path)
 967 {
 968         return create(ef, path, EXFAT_ATTRIB_ARCH);
 969 }
 970
 971 int exfat_mkdir(struct exfat* ef, const char* path)
 972 {
 973         int rc;
 974         struct exfat_node* node;
 975
 976         rc = create(ef, path, EXFAT_ATTRIB_DIR);
 977         if (rc != 0)
 978                 return rc;
 979         rc = exfat_lookup(ef, &node, path);
 980         if (rc != 0)
 981                 return 0;
 982         /* directories always have at least one cluster */
 983         rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
 984         if (rc != 0)
 985         {
 986                 delete(ef, node);
 987                 exfat_put_node(ef, node);
 988                 return rc;
 989         }
 990         rc = exfat_flush_node(ef, node);
 991         if (rc != 0)
 992         {
 993                 delete(ef, node);
 994                 exfat_put_node(ef, node);
 995                 return rc;
 996         }
 997         exfat_put_node(ef, node);
 998         return 0;
 999 }
1000
1001 static int rename_entry(struct exfat* ef, struct exfat_node* dir,
1002                 struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
1003                 off_t new_offset)
1004 {
1005         struct exfat_entry_meta1 meta1;
1006         struct exfat_entry_meta2 meta2;
1007         cluster_t old_cluster = node->entry_cluster;
1008         off_t old_offset = node->entry_offset;
1009         const size_t name_length = utf16_length(name);
1010         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
1011         int i;
1012
1013         if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
1014                         co2o(ef, old_cluster, old_offset)) < 0)
1015         {
1016                 exfat_error("failed to read meta1 entry on rename");
1017                 return -EIO;
1018         }
1019         if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
1020                 return -EIO;
1021         if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
1022                         co2o(ef, old_cluster, old_offset)) < 0)
1023         {
1024                 exfat_error("failed to read meta2 entry on rename");
1025                 return -EIO;
1026         }
1027         meta1.continuations = 1 + name_entries;
1028         meta2.name_hash = exfat_calc_name_hash(ef, name);
1029         meta2.name_length = name_length;
1030         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
1031
1032         if (!erase_entry(ef, node))
1033                 return -EIO;
1034
1035         node->entry_cluster = new_cluster;
1036         node->entry_offset = new_offset;
1037
1038         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
1039                         co2o(ef, new_cluster, new_offset)) < 0)
1040         {
1041                 exfat_error("failed to write meta1 entry on rename");
1042                 return -EIO;
1043         }
1044         if (!next_entry(ef, dir, &new_cluster, &new_offset))
1045                 return -EIO;
1046         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
1047                         co2o(ef, new_cluster, new_offset)) < 0)
1048         {
1049                 exfat_error("failed to write meta2 entry on rename");
1050                 return -EIO;
1051         }
1052
1053         for (i = 0; i < name_entries; i++)
1054         {
1055                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
1056                 memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
1057                                 EXFAT_ENAME_MAX * sizeof(le16_t));
1058                 if (!next_entry(ef, dir, &new_cluster, &new_offset))
1059                         return -EIO;
1060                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
1061                                 co2o(ef, new_cluster, new_offset)) < 0)
1062                 {
1063                         exfat_error("failed to write name entry on rename");
1064                         return -EIO;
1065                 }
1066         }
1067
1068         memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
1069         tree_detach(node);
1070         tree_attach(dir, node);
1071         return 0;
1072 }
1073
1074 int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
1075 {
1076         struct exfat_node* node;
1077         struct exfat_node* existing;
1078         struct exfat_node* dir;
1079         cluster_t cluster = EXFAT_CLUSTER_BAD;
1080         off_t offset = -1;
1081         le16_t name[EXFAT_NAME_MAX + 1];
1082         int rc;
1083
1084         rc = exfat_lookup(ef, &node, old_path);
1085         if (rc != 0)
1086                 return rc;
1087
1088         rc = exfat_split(ef, &dir, &existing, name, new_path);
1089         if (rc != 0)
1090         {
1091                 exfat_put_node(ef, node);
1092                 return rc;
1093         }
1094
1095         /* check that target is not a subdirectory of the source */
1096         if (node->flags & EXFAT_ATTRIB_DIR)
1097         {
1098                 struct exfat_node* p;
1099
1100                 for (p = dir; p; p = p->parent)
1101                         if (node == p)
1102                         {
1103                                 if (existing != NULL)
1104                                         exfat_put_node(ef, existing);
1105                                 exfat_put_node(ef, dir);
1106                                 exfat_put_node(ef, node);
1107                                 return -EINVAL;
1108                         }
1109         }
1110
1111         if (existing != NULL)
1112         {
1113                 /* remove target if it's not the same node as source */
1114                 if (existing != node)
1115                 {
1116                         if (existing->flags & EXFAT_ATTRIB_DIR)
1117                         {
1118                                 if (node->flags & EXFAT_ATTRIB_DIR)
1119                                         rc = exfat_rmdir(ef, existing);
1120                                 else
1121                                         rc = -ENOTDIR;
1122                         }
1123                         else
1124                         {
1125                                 if (!(node->flags & EXFAT_ATTRIB_DIR))
1126                                         rc = exfat_unlink(ef, existing);
1127                                 else
1128                                         rc = -EISDIR;
1129                         }
1130                         exfat_put_node(ef, existing);
1131                         if (rc != 0)
1132                         {
1133                                 exfat_put_node(ef, dir);
1134                                 exfat_put_node(ef, node);
1135                                 return rc;
1136                         }
1137                 }
1138                 else
1139                         exfat_put_node(ef, existing);
1140         }
1141
1142         rc = find_slot(ef, dir, &cluster, &offset,
1143                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
1144         if (rc != 0)
1145         {
1146                 exfat_put_node(ef, dir);
1147                 exfat_put_node(ef, node);
1148                 return rc;
1149         }
1150         rc = rename_entry(ef, dir, node, name, cluster, offset);
1151         exfat_put_node(ef, dir);
1152         exfat_put_node(ef, node);
1153         return rc;
1154 }
1155
1156 void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
1157 {
1158         node->atime = tv[0].tv_sec;
1159         node->mtime = tv[1].tv_sec;
1160         node->flags |= EXFAT_ATTRIB_DIRTY;
1161 }
1162
1163 void exfat_update_atime(struct exfat_node* node)
1164 {
1165         node->atime = time(NULL);
1166         node->flags |= EXFAT_ATTRIB_DIRTY;
1167 }
1168
1169 void exfat_update_mtime(struct exfat_node* node)
1170 {
1171         node->mtime = time(NULL);
1172         node->flags |= EXFAT_ATTRIB_DIRTY;
1173 }
1174
1175 const char* exfat_get_label(struct exfat* ef)
1176 {
1177         return ef->label;
1178 }
1179
1180 static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
1181 {
1182         struct iterator it;
1183         int rc;
1184
1185         rc = opendir(ef, ef->root, &it);
1186         if (rc != 0)
1187                 return rc;
1188
1189         for (;;)
1190         {
1191                 if (it.offset >= ef->root->size)
1192                 {
1193                         closedir(&it);
1194                         return -ENOENT;
1195                 }
1196
1197                 if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
1198                 {
1199                         *cluster = it.cluster;
1200                         *offset = it.offset;
1201                         closedir(&it);
1202                         return 0;
1203                 }
1204
1205                 if (!fetch_next_entry(ef, ef->root, &it))
1206                 {
1207                         closedir(&it);
1208                         return -EIO;
1209                 }
1210         }
1211 }
1212
1213 int exfat_set_label(struct exfat* ef, const char* label)
1214 {
1215         le16_t label_utf16[EXFAT_ENAME_MAX + 1];
1216         int rc;
1217         cluster_t cluster;
1218         off_t offset;
1219         struct exfat_entry_label entry;
1220
1221         memset(label_utf16, 0, sizeof(label_utf16));
1222         rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
1223         if (rc != 0)
1224                 return rc;
1225
1226         rc = find_label(ef, &cluster, &offset);
1227         if (rc == -ENOENT)
1228                 rc = find_slot(ef, ef->root, &cluster, &offset, 1);
1229         if (rc != 0)
1230                 return rc;
1231
1232         entry.type = EXFAT_ENTRY_LABEL;
1233         entry.length = utf16_length(label_utf16);
1234         memcpy(entry.name, label_utf16, sizeof(entry.name));
1235         if (entry.length == 0)
1236                 entry.type ^= EXFAT_ENTRY_VALID;
1237
1238         if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
1239                         co2o(ef, cluster, offset)) < 0)
1240         {
1241                 exfat_error("failed to write label entry");
1242                 return -EIO;
1243         }
1244         strcpy(ef->label, label);
1245         return 0;
1246 }