libexfat/node.c

   1 /*
   2         node.c (09.10.09)
   3         exFAT file system implementation library.
   4
   5         Free exFAT implementation.
   6         Copyright (C) 2010-2013  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 int 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 0;
 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 1;
 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 1;
 152                 }
 153         }
 154         return 0;
 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 real_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            It's unclear what is real_size field needed for. It usually equals to
 215            the size but may contain any value less than size (including 0).
 216         */
 217         if (real_size > node->size)
 218         {
 219                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 220                 exfat_error("`%s' has real size (%"PRIu64") greater than size "
 221                                 "(%"PRIu64")", buffer, real_size, node->size);
 222                 return false;
 223         }
 224
 225         return true;
 226 }
 227
 228 /*
 229  * Reads one entry in directory at position pointed by iterator and fills
 230  * node structure.
 231  */
 232 static int readdir(struct exfat* ef, const struct exfat_node* parent,
 233                 struct exfat_node** node, struct iterator* it)
 234 {
 235         int rc = -EIO;
 236         const struct exfat_entry* entry;
 237         const struct exfat_entry_meta1* meta1;
 238         const struct exfat_entry_meta2* meta2;
 239         const struct exfat_entry_name* file_name;
 240         const struct exfat_entry_upcase* upcase;
 241         const struct exfat_entry_bitmap* bitmap;
 242         const struct exfat_entry_label* label;
 243         uint8_t continuations = 0;
 244         le16_t* namep = NULL;
 245         uint16_t reference_checksum = 0;
 246         uint16_t actual_checksum = 0;
 247         uint64_t real_size = 0;
 248
 249         *node = NULL;
 250
 251         for (;;)
 252         {
 253                 if (it->offset >= parent->size)
 254                 {
 255                         if (continuations != 0)
 256                         {
 257                                 exfat_error("expected %hhu continuations", continuations);
 258                                 goto error;
 259                         }
 260                         return -ENOENT; /* that's OK, means end of directory */
 261                 }
 262
 263                 entry = get_entry_ptr(ef, it);
 264                 switch (entry->type)
 265                 {
 266                 case EXFAT_ENTRY_FILE:
 267                         if (continuations != 0)
 268                         {
 269                                 exfat_error("expected %hhu continuations before new entry",
 270                                                 continuations);
 271                                 goto error;
 272                         }
 273                         meta1 = (const struct exfat_entry_meta1*) entry;
 274                         continuations = meta1->continuations;
 275                         /* each file entry must have at least 2 continuations:
 276                            info and name */
 277                         if (continuations < 2)
 278                         {
 279                                 exfat_error("too few continuations (%hhu)", continuations);
 280                                 goto error;
 281                         }
 282                         if (continuations > 1 +
 283                                         DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
 284                         {
 285                                 exfat_error("too many continuations (%hhu)", continuations);
 286                                 goto error;
 287                         }
 288                         reference_checksum = le16_to_cpu(meta1->checksum);
 289                         actual_checksum = exfat_start_checksum(meta1);
 290                         *node = allocate_node();
 291                         if (*node == NULL)
 292                         {
 293                                 rc = -ENOMEM;
 294                                 goto error;
 295                         }
 296                         /* new node has zero reference counter */
 297                         (*node)->entry_cluster = it->cluster;
 298                         (*node)->entry_offset = it->offset;
 299                         init_node_meta1(*node, meta1);
 300                         namep = (*node)->name;
 301                         break;
 302
 303                 case EXFAT_ENTRY_FILE_INFO:
 304                         if (continuations < 2)
 305                         {
 306                                 exfat_error("unexpected continuation (%hhu)",
 307                                                 continuations);
 308                                 goto error;
 309                         }
 310                         meta2 = (const struct exfat_entry_meta2*) entry;
 311                         if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
 312                         {
 313                                 exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
 314                                 goto error;
 315                         }
 316                         init_node_meta2(*node, meta2);
 317                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 318                         real_size = le64_to_cpu(meta2->real_size);
 319                         /* empty files must be marked as non-contiguous */
 320                         if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
 321                         {
 322                                 exfat_error("empty file marked as contiguous (0x%hhx)",
 323                                                 meta2->flags);
 324                                 goto error;
 325                         }
 326                         /* directories must be aligned on at cluster boundary */
 327                         if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
 328                                 (*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
 329                         {
 330                                 exfat_error("directory has invalid size %"PRIu64" bytes",
 331                                                 (*node)->size);
 332                                 goto error;
 333                         }
 334                         --continuations;
 335                         break;
 336
 337                 case EXFAT_ENTRY_FILE_NAME:
 338                         if (continuations == 0)
 339                         {
 340                                 exfat_error("unexpected continuation");
 341                                 goto error;
 342                         }
 343                         file_name = (const struct exfat_entry_name*) entry;
 344                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 345
 346                         memcpy(namep, file_name->name,
 347                                         MIN(EXFAT_ENAME_MAX,
 348                                                 ((*node)->name + EXFAT_NAME_MAX - namep)) *
 349                                         sizeof(le16_t));
 350                         namep += EXFAT_ENAME_MAX;
 351                         if (--continuations == 0)
 352                         {
 353                                 if (!check_node(*node, actual_checksum, reference_checksum,
 354                                                 real_size))
 355                                         goto error;
 356                                 if (fetch_next_entry(ef, parent, it) != 0)
 357                                         goto error;
 358                                 return 0; /* entry completed */
 359                         }
 360                         break;
 361
 362                 case EXFAT_ENTRY_UPCASE:
 363                         if (ef->upcase != NULL)
 364                                 break;
 365                         upcase = (const struct exfat_entry_upcase*) entry;
 366                         if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
 367                         {
 368                                 exfat_error("invalid cluster 0x%x in upcase table",
 369                                                 le32_to_cpu(upcase->start_cluster));
 370                                 goto error;
 371                         }
 372                         if (le64_to_cpu(upcase->size) == 0 ||
 373                                 le64_to_cpu(upcase->size) > 0xffff * sizeof(uint16_t) ||
 374                                 le64_to_cpu(upcase->size) % sizeof(uint16_t) != 0)
 375                         {
 376                                 exfat_error("bad upcase table size (%"PRIu64" bytes)",
 377                                                 le64_to_cpu(upcase->size));
 378                                 goto error;
 379                         }
 380                         ef->upcase = malloc(le64_to_cpu(upcase->size));
 381                         if (ef->upcase == NULL)
 382                         {
 383                                 exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
 384                                                 le64_to_cpu(upcase->size));
 385                                 rc = -ENOMEM;
 386                                 goto error;
 387                         }
 388                         ef->upcase_chars = le64_to_cpu(upcase->size) / sizeof(le16_t);
 389
 390                         if (exfat_pread(ef->dev, ef->upcase, le64_to_cpu(upcase->size),
 391                                         exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 392                         {
 393                                 exfat_error("failed to read upper case table "
 394                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 395                                                 le64_to_cpu(upcase->size),
 396                                                 le32_to_cpu(upcase->start_cluster));
 397                                 goto error;
 398                         }
 399                         break;
 400
 401                 case EXFAT_ENTRY_BITMAP:
 402                         bitmap = (const struct exfat_entry_bitmap*) entry;
 403                         ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
 404                         if (CLUSTER_INVALID(ef->cmap.start_cluster))
 405                         {
 406                                 exfat_error("invalid cluster 0x%x in clusters bitmap",
 407                                                 ef->cmap.start_cluster);
 408                                 goto error;
 409                         }
 410                         ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 411                                 EXFAT_FIRST_DATA_CLUSTER;
 412                         if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 413                         {
 414                                 exfat_error("invalid clusters bitmap size: %"PRIu64
 415                                                 " (expected at least %u)",
 416                                                 le64_to_cpu(bitmap->size),
 417                                                 DIV_ROUND_UP(ef->cmap.size, 8));
 418                                 goto error;
 419                         }
 420                         /* FIXME bitmap can be rather big, up to 512 MB */
 421                         ef->cmap.chunk_size = ef->cmap.size;
 422                         ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 423                         if (ef->cmap.chunk == NULL)
 424                         {
 425                                 exfat_error("failed to allocate clusters bitmap chunk "
 426                                                 "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
 427                                 rc = -ENOMEM;
 428                                 goto error;
 429                         }
 430
 431                         if (exfat_pread(ef->dev, ef->cmap.chunk,
 432                                         BMAP_SIZE(ef->cmap.chunk_size),
 433                                         exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
 434                         {
 435                                 exfat_error("failed to read clusters bitmap "
 436                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 437                                                 le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
 438                                 goto error;
 439                         }
 440                         break;
 441
 442                 case EXFAT_ENTRY_LABEL:
 443                         label = (const struct exfat_entry_label*) entry;
 444                         if (label->length > EXFAT_ENAME_MAX)
 445                         {
 446                                 exfat_error("too long label (%hhu chars)", label->length);
 447                                 goto error;
 448                         }
 449                         if (utf16_to_utf8(ef->label, label->name,
 450                                                 sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
 451                                 goto error;
 452                         break;
 453
 454                 default:
 455                         if (entry->type & EXFAT_ENTRY_VALID)
 456                         {
 457                                 exfat_error("unknown entry type 0x%hhx", entry->type);
 458                                 goto error;
 459                         }
 460                         break;
 461                 }
 462
 463                 if (fetch_next_entry(ef, parent, it) != 0)
 464                         goto error;
 465         }
 466         /* we never reach here */
 467
 468 error:
 469         free(*node);
 470         *node = NULL;
 471         return rc;
 472 }
 473
 474 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 475 {
 476         struct iterator it;
 477         int rc;
 478         struct exfat_node* node;
 479         struct exfat_node* current = NULL;
 480
 481         if (dir->flags & EXFAT_ATTRIB_CACHED)
 482                 return 0; /* already cached */
 483
 484         rc = opendir(ef, dir, &it);
 485         if (rc != 0)
 486                 return rc;
 487         while ((rc = readdir(ef, dir, &node, &it)) == 0)
 488         {
 489                 node->parent = dir;
 490                 if (current != NULL)
 491                 {
 492                         current->next = node;
 493                         node->prev = current;
 494                 }
 495                 else
 496                         dir->child = node;
 497
 498                 current = node;
 499         }
 500         closedir(&it);
 501
 502         if (rc != -ENOENT)
 503         {
 504                 /* rollback */
 505                 for (current = dir->child; current; current = node)
 506                 {
 507                         node = current->next;
 508                         free(current);
 509                 }
 510                 dir->child = NULL;
 511                 return rc;
 512         }
 513
 514         dir->flags |= EXFAT_ATTRIB_CACHED;
 515         return 0;
 516 }
 517
 518 static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
 519 {
 520         node->parent = dir;
 521         if (dir->child)
 522         {
 523                 dir->child->prev = node;
 524                 node->next = dir->child;
 525         }
 526         dir->child = node;
 527 }
 528
 529 static void tree_detach(struct exfat_node* node)
 530 {
 531         if (node->prev)
 532                 node->prev->next = node->next;
 533         else /* this is the first node in the list */
 534                 node->parent->child = node->next;
 535         if (node->next)
 536                 node->next->prev = node->prev;
 537         node->parent = NULL;
 538         node->prev = NULL;
 539         node->next = NULL;
 540 }
 541
 542 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 543 {
 544         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 545
 546         while (node->child)
 547         {
 548                 struct exfat_node* p = node->child;
 549                 reset_cache(ef, p);
 550                 tree_detach(p);
 551                 free(p);
 552         }
 553         node->flags &= ~EXFAT_ATTRIB_CACHED;
 554         if (node->references != 0)
 555         {
 556                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 557                 exfat_warn("non-zero reference counter (%d) for `%s'",
 558                                 node->references, buffer);
 559         }
 560         if (node != ef->root && (node->flags & EXFAT_ATTRIB_DIRTY))
 561         {
 562                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 563                 exfat_bug("node `%s' is dirty", buffer);
 564         }
 565         while (node->references)
 566                 exfat_put_node(ef, node);
 567 }
 568
 569 void exfat_reset_cache(struct exfat* ef)
 570 {
 571         reset_cache(ef, ef->root);
 572 }
 573
 574 static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 575                 cluster_t* cluster, off_t* offset)
 576 {
 577         *offset += sizeof(struct exfat_entry);
 578         if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
 579         {
 580                 *cluster = exfat_next_cluster(ef, parent, *cluster);
 581                 if (CLUSTER_INVALID(*cluster))
 582                 {
 583                         exfat_error("invalid cluster %#x while getting next entry",
 584                                         *cluster);
 585                         return false;
 586                 }
 587         }
 588         return true;
 589 }
 590
 591 int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 592 {
 593         cluster_t cluster;
 594         off_t offset;
 595         off_t meta1_offset, meta2_offset;
 596         struct exfat_entry_meta1 meta1;
 597         struct exfat_entry_meta2 meta2;
 598
 599         if (!(node->flags & EXFAT_ATTRIB_DIRTY))
 600                 return 0; /* no need to flush */
 601
 602         if (ef->ro)
 603                 exfat_bug("unable to flush node to read-only FS");
 604
 605         if (node->parent == NULL)
 606                 return 0; /* do not flush unlinked node */
 607
 608         cluster = node->entry_cluster;
 609         offset = node->entry_offset;
 610         meta1_offset = co2o(ef, cluster, offset);
 611         if (!next_entry(ef, node->parent, &cluster, &offset))
 612                 return -EIO;
 613         meta2_offset = co2o(ef, cluster, offset);
 614
 615         if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 616         {
 617                 exfat_error("failed to read meta1 entry on flush");
 618                 return -EIO;
 619         }
 620         if (meta1.type != EXFAT_ENTRY_FILE)
 621                 exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
 622         meta1.attrib = cpu_to_le16(node->flags);
 623         exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 624         exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 625
 626         if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 627         {
 628                 exfat_error("failed to read meta2 entry on flush");
 629                 return -EIO;
 630         }
 631         if (meta2.type != EXFAT_ENTRY_FILE_INFO)
 632                 exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
 633         meta2.size = meta2.real_size = cpu_to_le64(node->size);
 634         meta2.start_cluster = cpu_to_le32(node->start_cluster);
 635         meta2.flags = EXFAT_FLAG_ALWAYS1;
 636         /* empty files must not be marked as contiguous */
 637         if (node->size != 0 && IS_CONTIGUOUS(*node))
 638                 meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 639         /* name hash remains unchanged, no need to recalculate it */
 640
 641         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 642
 643         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 644         {
 645                 exfat_error("failed to write meta1 entry on flush");
 646                 return -EIO;
 647         }
 648         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 649         {
 650                 exfat_error("failed to write meta2 entry on flush");
 651                 return -EIO;
 652         }
 653
 654         node->flags &= ~EXFAT_ATTRIB_DIRTY;
 655         return 0;
 656 }
 657
 658 static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 659 {
 660         cluster_t cluster = node->entry_cluster;
 661         off_t offset = node->entry_offset;
 662         int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
 663         uint8_t entry_type;
 664
 665         entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
 666         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 667         {
 668                 exfat_error("failed to erase meta1 entry");
 669                 return false;
 670         }
 671
 672         if (!next_entry(ef, node->parent, &cluster, &offset))
 673                 return false;
 674         entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
 675         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 676         {
 677                 exfat_error("failed to erase meta2 entry");
 678                 return false;
 679         }
 680
 681         while (name_entries--)
 682         {
 683                 if (!next_entry(ef, node->parent, &cluster, &offset))
 684                         return false;
 685                 entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
 686                 if (exfat_pwrite(ef->dev, &entry_type, 1,
 687                                 co2o(ef, cluster, offset)) < 0)
 688                 {
 689                         exfat_error("failed to erase name entry");
 690                         return false;
 691                 }
 692         }
 693         return true;
 694 }
 695
 696 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 697                 off_t deleted_offset)
 698 {
 699         const struct exfat_node* node;
 700         const struct exfat_node* last_node;
 701         uint64_t entries = 0;
 702         uint64_t new_size;
 703
 704         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 705                 exfat_bug("attempted to shrink a file");
 706         if (!(dir->flags & EXFAT_ATTRIB_CACHED))
 707                 exfat_bug("attempted to shrink uncached directory");
 708
 709         for (last_node = node = dir->child; node; node = node->next)
 710         {
 711                 if (deleted_offset < node->entry_offset)
 712                 {
 713                         /* there are other entries after the removed one, no way to shrink
 714                            this directory */
 715                         return 0;
 716                 }
 717                 if (last_node->entry_offset < node->entry_offset)
 718                         last_node = node;
 719         }
 720
 721         if (last_node)
 722         {
 723                 /* offset of the last entry */
 724                 entries += last_node->entry_offset / sizeof(struct exfat_entry);
 725                 /* two subentries with meta info */
 726                 entries += 2;
 727                 /* subentries with file name */
 728                 entries += DIV_ROUND_UP(utf16_length(last_node->name),
 729                                 EXFAT_ENAME_MAX);
 730         }
 731
 732         new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
 733                                  CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
 734         if (new_size == 0) /* directory always has at least 1 cluster */
 735                 new_size = CLUSTER_SIZE(*ef->sb);
 736         if (new_size == dir->size)
 737                 return 0;
 738         return exfat_truncate(ef, dir, new_size, true);
 739 }
 740
 741 static int delete(struct exfat* ef, struct exfat_node* node)
 742 {
 743         struct exfat_node* parent = node->parent;
 744         off_t deleted_offset = node->entry_offset;
 745         int rc;
 746
 747         exfat_get_node(parent);
 748         if (!erase_entry(ef, node))
 749         {
 750                 exfat_put_node(ef, parent);
 751                 return -EIO;
 752         }
 753         exfat_update_mtime(parent);
 754         tree_detach(node);
 755         rc = shrink_directory(ef, parent, deleted_offset);
 756         node->flags |= EXFAT_ATTRIB_UNLINKED;
 757         if (rc != 0)
 758         {
 759                 exfat_flush_node(ef, parent);
 760                 exfat_put_node(ef, parent);
 761                 return rc;
 762         }
 763         rc = exfat_flush_node(ef, parent);
 764         exfat_put_node(ef, parent);
 765         return rc;
 766 }
 767
 768 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 769 {
 770         if (node->flags & EXFAT_ATTRIB_DIR)
 771                 return -EISDIR;
 772         return delete(ef, node);
 773 }
 774
 775 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 776 {
 777         int rc;
 778
 779         if (!(node->flags & EXFAT_ATTRIB_DIR))
 780                 return -ENOTDIR;
 781         /* check that directory is empty */
 782         rc = exfat_cache_directory(ef, node);
 783         if (rc != 0)
 784                 return rc;
 785         if (node->child)
 786                 return -ENOTEMPTY;
 787         return delete(ef, node);
 788 }
 789
 790 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 791                 uint64_t asize, uint32_t difference)
 792 {
 793         return exfat_truncate(ef, dir,
 794                         DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
 795                                 * CLUSTER_SIZE(*ef->sb), true);
 796 }
 797
 798 static int find_slot(struct exfat* ef, struct exfat_node* dir,
 799                 cluster_t* cluster, off_t* offset, int subentries)
 800 {
 801         struct iterator it;
 802         int rc;
 803         const struct exfat_entry* entry;
 804         int contiguous = 0;
 805
 806         rc = opendir(ef, dir, &it);
 807         if (rc != 0)
 808                 return rc;
 809         for (;;)
 810         {
 811                 if (contiguous == 0)
 812                 {
 813                         *cluster = it.cluster;
 814                         *offset = it.offset;
 815                 }
 816                 entry = get_entry_ptr(ef, &it);
 817                 if (entry->type & EXFAT_ENTRY_VALID)
 818                         contiguous = 0;
 819                 else
 820                         contiguous++;
 821                 if (contiguous == subentries)
 822                         break;  /* suitable slot is found */
 823                 if (it.offset + sizeof(struct exfat_entry) >= dir->size)
 824                 {
 825                         rc = grow_directory(ef, dir, dir->size,
 826                                         (subentries - contiguous) * sizeof(struct exfat_entry));
 827                         if (rc != 0)
 828                         {
 829                                 closedir(&it);
 830                                 return rc;
 831                         }
 832                 }
 833                 if (fetch_next_entry(ef, dir, &it) != 0)
 834                 {
 835                         closedir(&it);
 836                         return -EIO;
 837                 }
 838         }
 839         closedir(&it);
 840         return 0;
 841 }
 842
 843 static int write_entry(struct exfat* ef, struct exfat_node* dir,
 844                 const le16_t* name, cluster_t cluster, off_t offset, uint16_t attrib)
 845 {
 846         struct exfat_node* node;
 847         struct exfat_entry_meta1 meta1;
 848         struct exfat_entry_meta2 meta2;
 849         const size_t name_length = utf16_length(name);
 850         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 851         int i;
 852
 853         node = allocate_node();
 854         if (node == NULL)
 855                 return -ENOMEM;
 856         node->entry_cluster = cluster;
 857         node->entry_offset = offset;
 858         memcpy(node->name, name, name_length * sizeof(le16_t));
 859
 860         memset(&meta1, 0, sizeof(meta1));
 861         meta1.type = EXFAT_ENTRY_FILE;
 862         meta1.continuations = 1 + name_entries;
 863         meta1.attrib = cpu_to_le16(attrib);
 864         exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
 865                         &meta1.crtime_cs);
 866         meta1.adate = meta1.mdate = meta1.crdate;
 867         meta1.atime = meta1.mtime = meta1.crtime;
 868         meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 869
 870         memset(&meta2, 0, sizeof(meta2));
 871         meta2.type = EXFAT_ENTRY_FILE_INFO;
 872         meta2.flags = EXFAT_FLAG_ALWAYS1;
 873         meta2.name_length = name_length;
 874         meta2.name_hash = exfat_calc_name_hash(ef, node->name);
 875         meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
 876
 877         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 878
 879         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 880                         co2o(ef, cluster, offset)) < 0)
 881         {
 882                 exfat_error("failed to write meta1 entry");
 883                 return -EIO;
 884         }
 885         if (!next_entry(ef, dir, &cluster, &offset))
 886                 return -EIO;
 887         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 888                         co2o(ef, cluster, offset)) < 0)
 889         {
 890                 exfat_error("failed to write meta2 entry");
 891                 return -EIO;
 892         }
 893         for (i = 0; i < name_entries; i++)
 894         {
 895                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 896                 memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
 897                                 MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
 898                                 sizeof(le16_t));
 899                 if (!next_entry(ef, dir, &cluster, &offset))
 900                         return -EIO;
 901                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 902                                 co2o(ef, cluster, offset)) < 0)
 903                 {
 904                         exfat_error("failed to write name entry");
 905                         return -EIO;
 906                 }
 907         }
 908
 909         init_node_meta1(node, &meta1);
 910         init_node_meta2(node, &meta2);
 911
 912         tree_attach(dir, node);
 913         exfat_update_mtime(dir);
 914         return 0;
 915 }
 916
 917 static int create(struct exfat* ef, const char* path, uint16_t attrib)
 918 {
 919         struct exfat_node* dir;
 920         struct exfat_node* existing;
 921         cluster_t cluster = EXFAT_CLUSTER_BAD;
 922         off_t offset = -1;
 923         le16_t name[EXFAT_NAME_MAX + 1];
 924         int rc;
 925
 926         rc = exfat_split(ef, &dir, &existing, name, path);
 927         if (rc != 0)
 928                 return rc;
 929         if (existing != NULL)
 930         {
 931                 exfat_put_node(ef, existing);
 932                 exfat_put_node(ef, dir);
 933                 return -EEXIST;
 934         }
 935
 936         rc = find_slot(ef, dir, &cluster, &offset,
 937                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
 938         if (rc != 0)
 939         {
 940                 exfat_put_node(ef, dir);
 941                 return rc;
 942         }
 943         rc = write_entry(ef, dir, name, cluster, offset, attrib);
 944         if (rc != 0)
 945         {
 946                 exfat_put_node(ef, dir);
 947                 return rc;
 948         }
 949         rc = exfat_flush_node(ef, dir);
 950         exfat_put_node(ef, dir);
 951         return rc;
 952 }
 953
 954 int exfat_mknod(struct exfat* ef, const char* path)
 955 {
 956         return create(ef, path, EXFAT_ATTRIB_ARCH);
 957 }
 958
 959 int exfat_mkdir(struct exfat* ef, const char* path)
 960 {
 961         int rc;
 962         struct exfat_node* node;
 963
 964         rc = create(ef, path, EXFAT_ATTRIB_ARCH | EXFAT_ATTRIB_DIR);
 965         if (rc != 0)
 966                 return rc;
 967         rc = exfat_lookup(ef, &node, path);
 968         if (rc != 0)
 969                 return 0;
 970         /* directories always have at least one cluster */
 971         rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
 972         if (rc != 0)
 973         {
 974                 delete(ef, node);
 975                 exfat_put_node(ef, node);
 976                 return rc;
 977         }
 978         rc = exfat_flush_node(ef, node);
 979         if (rc != 0)
 980         {
 981                 delete(ef, node);
 982                 exfat_put_node(ef, node);
 983                 return rc;
 984         }
 985         exfat_put_node(ef, node);
 986         return 0;
 987 }
 988
 989 static int rename_entry(struct exfat* ef, struct exfat_node* dir,
 990                 struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
 991                 off_t new_offset)
 992 {
 993         struct exfat_entry_meta1 meta1;
 994         struct exfat_entry_meta2 meta2;
 995         cluster_t old_cluster = node->entry_cluster;
 996         off_t old_offset = node->entry_offset;
 997         const size_t name_length = utf16_length(name);
 998         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 999         int i;
1000
1001         if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
1002                         co2o(ef, old_cluster, old_offset)) < 0)
1003         {
1004                 exfat_error("failed to read meta1 entry on rename");
1005                 return -EIO;
1006         }
1007         if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
1008                 return -EIO;
1009         if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
1010                         co2o(ef, old_cluster, old_offset)) < 0)
1011         {
1012                 exfat_error("failed to read meta2 entry on rename");
1013                 return -EIO;
1014         }
1015         meta1.continuations = 1 + name_entries;
1016         meta2.name_hash = exfat_calc_name_hash(ef, name);
1017         meta2.name_length = name_length;
1018         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
1019
1020         if (!erase_entry(ef, node))
1021                 return -EIO;
1022
1023         node->entry_cluster = new_cluster;
1024         node->entry_offset = new_offset;
1025
1026         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
1027                         co2o(ef, new_cluster, new_offset)) < 0)
1028         {
1029                 exfat_error("failed to write meta1 entry on rename");
1030                 return -EIO;
1031         }
1032         if (!next_entry(ef, dir, &new_cluster, &new_offset))
1033                 return -EIO;
1034         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
1035                         co2o(ef, new_cluster, new_offset)) < 0)
1036         {
1037                 exfat_error("failed to write meta2 entry on rename");
1038                 return -EIO;
1039         }
1040
1041         for (i = 0; i < name_entries; i++)
1042         {
1043                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
1044                 memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
1045                                 EXFAT_ENAME_MAX * sizeof(le16_t));
1046                 if (!next_entry(ef, dir, &new_cluster, &new_offset))
1047                         return -EIO;
1048                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
1049                                 co2o(ef, new_cluster, new_offset)) < 0)
1050                 {
1051                         exfat_error("failed to write name entry on rename");
1052                         return -EIO;
1053                 }
1054         }
1055
1056         memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
1057         tree_detach(node);
1058         tree_attach(dir, node);
1059         return 0;
1060 }
1061
1062 int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
1063 {
1064         struct exfat_node* node;
1065         struct exfat_node* existing;
1066         struct exfat_node* dir;
1067         cluster_t cluster = EXFAT_CLUSTER_BAD;
1068         off_t offset = -1;
1069         le16_t name[EXFAT_NAME_MAX + 1];
1070         int rc;
1071
1072         rc = exfat_lookup(ef, &node, old_path);
1073         if (rc != 0)
1074                 return rc;
1075
1076         rc = exfat_split(ef, &dir, &existing, name, new_path);
1077         if (rc != 0)
1078         {
1079                 exfat_put_node(ef, node);
1080                 return rc;
1081         }
1082
1083         /* check that target is not a subdirectory of the source */
1084         if (node->flags & EXFAT_ATTRIB_DIR)
1085         {
1086                 struct exfat_node* p;
1087
1088                 for (p = dir; p; p = p->parent)
1089                         if (node == p)
1090                         {
1091                                 if (existing != NULL)
1092                                         exfat_put_node(ef, existing);
1093                                 exfat_put_node(ef, dir);
1094                                 exfat_put_node(ef, node);
1095                                 return -EINVAL;
1096                         }
1097         }
1098
1099         if (existing != NULL)
1100         {
1101                 /* remove target if it's not the same node as source */
1102                 if (existing != node)
1103                 {
1104                         if (existing->flags & EXFAT_ATTRIB_DIR)
1105                         {
1106                                 if (node->flags & EXFAT_ATTRIB_DIR)
1107                                         rc = exfat_rmdir(ef, existing);
1108                                 else
1109                                         rc = -ENOTDIR;
1110                         }
1111                         else
1112                         {
1113                                 if (!(node->flags & EXFAT_ATTRIB_DIR))
1114                                         rc = exfat_unlink(ef, existing);
1115                                 else
1116                                         rc = -EISDIR;
1117                         }
1118                         exfat_put_node(ef, existing);
1119                         if (rc != 0)
1120                         {
1121                                 exfat_put_node(ef, dir);
1122                                 exfat_put_node(ef, node);
1123                                 return rc;
1124                         }
1125                 }
1126                 else
1127                         exfat_put_node(ef, existing);
1128         }
1129
1130         rc = find_slot(ef, dir, &cluster, &offset,
1131                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
1132         if (rc != 0)
1133         {
1134                 exfat_put_node(ef, dir);
1135                 exfat_put_node(ef, node);
1136                 return rc;
1137         }
1138         rc = rename_entry(ef, dir, node, name, cluster, offset);
1139         exfat_put_node(ef, dir);
1140         exfat_put_node(ef, node);
1141         return rc;
1142 }
1143
1144 void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
1145 {
1146         node->atime = tv[0].tv_sec;
1147         node->mtime = tv[1].tv_sec;
1148         node->flags |= EXFAT_ATTRIB_DIRTY;
1149 }
1150
1151 void exfat_update_atime(struct exfat_node* node)
1152 {
1153         node->atime = time(NULL);
1154         node->flags |= EXFAT_ATTRIB_DIRTY;
1155 }
1156
1157 void exfat_update_mtime(struct exfat_node* node)
1158 {
1159         node->mtime = time(NULL);
1160         node->flags |= EXFAT_ATTRIB_DIRTY;
1161 }
1162
1163 const char* exfat_get_label(struct exfat* ef)
1164 {
1165         return ef->label;
1166 }
1167
1168 static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
1169 {
1170         struct iterator it;
1171         int rc;
1172
1173         rc = opendir(ef, ef->root, &it);
1174         if (rc != 0)
1175                 return rc;
1176
1177         for (;;)
1178         {
1179                 if (it.offset >= ef->root->size)
1180                 {
1181                         closedir(&it);
1182                         return -ENOENT;
1183                 }
1184
1185                 if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
1186                 {
1187                         *cluster = it.cluster;
1188                         *offset = it.offset;
1189                         closedir(&it);
1190                         return 0;
1191                 }
1192
1193                 if (fetch_next_entry(ef, ef->root, &it) != 0)
1194                 {
1195                         closedir(&it);
1196                         return -EIO;
1197                 }
1198         }
1199 }
1200
1201 int exfat_set_label(struct exfat* ef, const char* label)
1202 {
1203         le16_t label_utf16[EXFAT_ENAME_MAX + 1];
1204         int rc;
1205         cluster_t cluster;
1206         off_t offset;
1207         struct exfat_entry_label entry;
1208
1209         memset(label_utf16, 0, sizeof(label_utf16));
1210         rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
1211         if (rc != 0)
1212                 return rc;
1213
1214         rc = find_label(ef, &cluster, &offset);
1215         if (rc == -ENOENT)
1216                 rc = find_slot(ef, ef->root, &cluster, &offset, 1);
1217         if (rc != 0)
1218                 return rc;
1219
1220         entry.type = EXFAT_ENTRY_LABEL;
1221         entry.length = utf16_length(label_utf16);
1222         memcpy(entry.name, label_utf16, sizeof(entry.name));
1223         if (entry.length == 0)
1224                 entry.type ^= EXFAT_ENTRY_VALID;
1225
1226         if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
1227                         co2o(ef, cluster, offset)) < 0)
1228         {
1229                 exfat_error("failed to write label entry");
1230                 return -EIO;
1231         }
1232         strcpy(ef->label, label);
1233         return 0;
1234 }