libexfat/node.c

   1 /*
   2         node.c (09.10.09)
   3         exFAT file system implementation library.
   4
   5         Free exFAT implementation.
   6         Copyright (C) 2010-2016  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                 free(it->chunk);
 113                 exfat_error("failed to read directory cluster %#x", it->cluster);
 114                 return -EIO;
 115         }
 116         return 0;
 117 }
 118
 119 static void closedir(struct iterator* it)
 120 {
 121         it->cluster = 0;
 122         it->offset = 0;
 123         it->contiguous = 0;
 124         free(it->chunk);
 125         it->chunk = NULL;
 126 }
 127
 128 static bool fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 129                 struct iterator* it)
 130 {
 131         /* move iterator to the next entry in the directory */
 132         it->offset += sizeof(struct exfat_entry);
 133         /* fetch the next cluster if needed */
 134         if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
 135         {
 136                 /* reached the end of directory; the caller should check this
 137                    condition too */
 138                 if (it->offset >= parent->size)
 139                         return true;
 140                 it->cluster = exfat_next_cluster(ef, parent, it->cluster);
 141                 if (CLUSTER_INVALID(it->cluster))
 142                 {
 143                         exfat_error("invalid cluster 0x%x while reading directory",
 144                                         it->cluster);
 145                         return false;
 146                 }
 147                 if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 148                                 exfat_c2o(ef, it->cluster)) < 0)
 149                 {
 150                         exfat_error("failed to read the next directory cluster %#x",
 151                                         it->cluster);
 152                         return false;
 153                 }
 154         }
 155         return true;
 156 }
 157
 158 static struct exfat_node* allocate_node(void)
 159 {
 160         struct exfat_node* node = malloc(sizeof(struct exfat_node));
 161         if (node == NULL)
 162         {
 163                 exfat_error("failed to allocate node");
 164                 return NULL;
 165         }
 166         memset(node, 0, sizeof(struct exfat_node));
 167         return node;
 168 }
 169
 170 static void init_node_meta1(struct exfat_node* node,
 171                 const struct exfat_entry_meta1* meta1)
 172 {
 173         node->flags = le16_to_cpu(meta1->attrib);
 174         node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
 175                         meta1->mtime_cs);
 176         /* there is no centiseconds field for atime */
 177         node->atime = exfat_exfat2unix(meta1->adate, meta1->atime, 0);
 178 }
 179
 180 static void init_node_meta2(struct exfat_node* node,
 181                 const struct exfat_entry_meta2* meta2)
 182 {
 183         node->size = le64_to_cpu(meta2->size);
 184         node->start_cluster = le32_to_cpu(meta2->start_cluster);
 185         node->fptr_cluster = node->start_cluster;
 186         if (meta2->flags & EXFAT_FLAG_CONTIGUOUS)
 187                 node->flags |= EXFAT_ATTRIB_CONTIGUOUS;
 188 }
 189
 190 static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
 191                 const struct iterator* it)
 192 {
 193         return (const struct exfat_entry*)
 194                         (it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
 195 }
 196
 197 static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
 198                 uint16_t reference_checksum, uint64_t valid_size)
 199 {
 200         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 201
 202         /*
 203            Validate checksum first. If it's invalid all other fields probably
 204            contain just garbage.
 205         */
 206         if (actual_checksum != reference_checksum)
 207         {
 208                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 209                 exfat_error("'%s' has invalid checksum (%#hx != %#hx)", buffer,
 210                                 actual_checksum, reference_checksum);
 211                 return false;
 212         }
 213
 214         /*
 215            exFAT does not support sparse files but allows files with uninitialized
 216            clusters. For such files valid_size means initialized data size and
 217            cannot be greater than file size. See SetFileValidData() function
 218            description in MSDN.
 219         */
 220         if (valid_size > node->size)
 221         {
 222                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 223                 exfat_error("'%s' has valid size (%"PRIu64") greater than size "
 224                                 "(%"PRIu64")", buffer, valid_size, node->size);
 225                 return false;
 226         }
 227
 228         return true;
 229 }
 230
 231 static void decompress_upcase(uint16_t* output, const le16_t* source,
 232                 size_t size)
 233 {
 234         size_t si;
 235         size_t oi;
 236
 237         for (oi = 0; oi < EXFAT_UPCASE_CHARS; oi++)
 238                 output[oi] = oi;
 239
 240         for (si = 0, oi = 0; si < size && oi < EXFAT_UPCASE_CHARS; si++)
 241         {
 242                 uint16_t ch = le16_to_cpu(source[si]);
 243
 244                 if (ch == 0xffff && si + 1 < size)      /* indicates a run */
 245                         oi += le16_to_cpu(source[++si]);
 246                 else
 247                         output[oi++] = ch;
 248         }
 249 }
 250
 251 /*
 252  * Reads one entry in directory at position pointed by iterator and fills
 253  * node structure.
 254  */
 255 static int readdir(struct exfat* ef, const struct exfat_node* parent,
 256                 struct exfat_node** node, struct iterator* it)
 257 {
 258         int rc = -EIO;
 259         const struct exfat_entry* entry;
 260         const struct exfat_entry_meta1* meta1;
 261         const struct exfat_entry_meta2* meta2;
 262         const struct exfat_entry_name* file_name;
 263         const struct exfat_entry_upcase* upcase;
 264         const struct exfat_entry_bitmap* bitmap;
 265         const struct exfat_entry_label* label;
 266         uint8_t continuations = 0;
 267         le16_t* namep = NULL;
 268         uint16_t reference_checksum = 0;
 269         uint16_t actual_checksum = 0;
 270         uint64_t valid_size = 0;
 271         uint64_t upcase_size = 0;
 272         le16_t* upcase_comp = NULL;
 273
 274         *node = NULL;
 275
 276         for (;;)
 277         {
 278                 if (it->offset >= parent->size)
 279                 {
 280                         if (continuations != 0)
 281                         {
 282                                 exfat_error("expected %hhu continuations", continuations);
 283                                 goto error;
 284                         }
 285                         return -ENOENT; /* that's OK, means end of directory */
 286                 }
 287
 288                 entry = get_entry_ptr(ef, it);
 289                 switch (entry->type)
 290                 {
 291                 case EXFAT_ENTRY_FILE:
 292                         if (continuations != 0)
 293                         {
 294                                 exfat_error("expected %hhu continuations before new entry",
 295                                                 continuations);
 296                                 goto error;
 297                         }
 298                         meta1 = (const struct exfat_entry_meta1*) entry;
 299                         continuations = meta1->continuations;
 300                         /* each file entry must have at least 2 continuations:
 301                            info and name */
 302                         if (continuations < 2)
 303                         {
 304                                 exfat_error("too few continuations (%hhu)", continuations);
 305                                 goto error;
 306                         }
 307                         if (continuations > 1 +
 308                                         DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
 309                         {
 310                                 exfat_error("too many continuations (%hhu)", continuations);
 311                                 goto error;
 312                         }
 313                         reference_checksum = le16_to_cpu(meta1->checksum);
 314                         actual_checksum = exfat_start_checksum(meta1);
 315                         *node = allocate_node();
 316                         if (*node == NULL)
 317                         {
 318                                 rc = -ENOMEM;
 319                                 goto error;
 320                         }
 321                         /* new node has zero reference counter */
 322                         (*node)->entry_cluster = it->cluster;
 323                         (*node)->entry_offset = it->offset;
 324                         init_node_meta1(*node, meta1);
 325                         namep = (*node)->name;
 326                         break;
 327
 328                 case EXFAT_ENTRY_FILE_INFO:
 329                         if (continuations < 2)
 330                         {
 331                                 exfat_error("unexpected continuation (%hhu)",
 332                                                 continuations);
 333                                 goto error;
 334                         }
 335                         meta2 = (const struct exfat_entry_meta2*) entry;
 336                         if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
 337                         {
 338                                 exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
 339                                 goto error;
 340                         }
 341                         init_node_meta2(*node, meta2);
 342                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 343                         valid_size = le64_to_cpu(meta2->valid_size);
 344                         /* empty files must be marked as non-contiguous */
 345                         if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
 346                         {
 347                                 exfat_error("empty file marked as contiguous (0x%hhx)",
 348                                                 meta2->flags);
 349                                 goto error;
 350                         }
 351                         /* directories must be aligned on at cluster boundary */
 352                         if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
 353                                 (*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
 354                         {
 355                                 exfat_error("directory has invalid size %"PRIu64" bytes",
 356                                                 (*node)->size);
 357                                 goto error;
 358                         }
 359                         --continuations;
 360                         break;
 361
 362                 case EXFAT_ENTRY_FILE_NAME:
 363                         if (continuations == 0)
 364                         {
 365                                 exfat_error("unexpected continuation");
 366                                 goto error;
 367                         }
 368                         file_name = (const struct exfat_entry_name*) entry;
 369                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 370
 371                         memcpy(namep, file_name->name,
 372                                         MIN(EXFAT_ENAME_MAX,
 373                                                 ((*node)->name + EXFAT_NAME_MAX - namep)) *
 374                                         sizeof(le16_t));
 375                         namep += EXFAT_ENAME_MAX;
 376                         if (--continuations == 0)
 377                         {
 378                                 if (!check_node(*node, actual_checksum, reference_checksum,
 379                                                 valid_size))
 380                                         goto error;
 381                                 if (!fetch_next_entry(ef, parent, it))
 382                                         goto error;
 383                                 return 0; /* entry completed */
 384                         }
 385                         break;
 386
 387                 case EXFAT_ENTRY_UPCASE:
 388                         if (ef->upcase != NULL)
 389                                 break;
 390                         upcase = (const struct exfat_entry_upcase*) entry;
 391                         if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
 392                         {
 393                                 exfat_error("invalid cluster 0x%x in upcase table",
 394                                                 le32_to_cpu(upcase->start_cluster));
 395                                 goto error;
 396                         }
 397                         upcase_size = le64_to_cpu(upcase->size);
 398                         if (upcase_size == 0 ||
 399                                 upcase_size > EXFAT_UPCASE_CHARS * sizeof(uint16_t) ||
 400                                 upcase_size % sizeof(uint16_t) != 0)
 401                         {
 402                                 exfat_error("bad upcase table size (%"PRIu64" bytes)",
 403                                                 upcase_size);
 404                                 goto error;
 405                         }
 406                         upcase_comp = malloc(upcase_size);
 407                         if (upcase_comp == NULL)
 408                         {
 409                                 exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
 410                                                 upcase_size);
 411                                 rc = -ENOMEM;
 412                                 goto error;
 413                         }
 414
 415                         /* read compressed upcase table */
 416                         if (exfat_pread(ef->dev, upcase_comp, upcase_size,
 417                                         exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 418                         {
 419                                 free(upcase_comp);
 420                                 exfat_error("failed to read upper case table "
 421                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 422                                                 upcase_size,
 423                                                 le32_to_cpu(upcase->start_cluster));
 424                                 goto error;
 425                         }
 426
 427                         /* decompress upcase table */
 428                         ef->upcase = calloc(EXFAT_UPCASE_CHARS, sizeof(uint16_t));
 429                         if (ef->upcase == NULL)
 430                         {
 431                                 free(upcase_comp);
 432                                 exfat_error("failed to allocate decompressed upcase table");
 433                                 rc = -ENOMEM;
 434                                 goto error;
 435                         }
 436                         decompress_upcase(ef->upcase, upcase_comp,
 437                                         upcase_size / sizeof(uint16_t));
 438                         free(upcase_comp);
 439                         break;
 440
 441                 case EXFAT_ENTRY_BITMAP:
 442                         bitmap = (const struct exfat_entry_bitmap*) entry;
 443                         ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
 444                         if (CLUSTER_INVALID(ef->cmap.start_cluster))
 445                         {
 446                                 exfat_error("invalid cluster 0x%x in clusters bitmap",
 447                                                 ef->cmap.start_cluster);
 448                                 goto error;
 449                         }
 450                         ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 451                                 EXFAT_FIRST_DATA_CLUSTER;
 452                         if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 453                         {
 454                                 exfat_error("invalid clusters bitmap size: %"PRIu64
 455                                                 " (expected at least %u)",
 456                                                 le64_to_cpu(bitmap->size),
 457                                                 DIV_ROUND_UP(ef->cmap.size, 8));
 458                                 goto error;
 459                         }
 460                         /* FIXME bitmap can be rather big, up to 512 MB */
 461                         ef->cmap.chunk_size = ef->cmap.size;
 462                         ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 463                         if (ef->cmap.chunk == NULL)
 464                         {
 465                                 exfat_error("failed to allocate clusters bitmap chunk "
 466                                                 "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
 467                                 rc = -ENOMEM;
 468                                 goto error;
 469                         }
 470
 471                         if (exfat_pread(ef->dev, ef->cmap.chunk,
 472                                         BMAP_SIZE(ef->cmap.chunk_size),
 473                                         exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
 474                         {
 475                                 exfat_error("failed to read clusters bitmap "
 476                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 477                                                 le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
 478                                 goto error;
 479                         }
 480                         break;
 481
 482                 case EXFAT_ENTRY_LABEL:
 483                         label = (const struct exfat_entry_label*) entry;
 484                         if (label->length > EXFAT_ENAME_MAX)
 485                         {
 486                                 exfat_error("too long label (%hhu chars)", label->length);
 487                                 goto error;
 488                         }
 489                         if (utf16_to_utf8(ef->label, label->name,
 490                                                 sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
 491                                 goto error;
 492                         break;
 493
 494                 default:
 495                         if (!(entry->type & EXFAT_ENTRY_VALID))
 496                                 break; /* deleted entry, ignore it */
 497                         if (!(entry->type & EXFAT_ENTRY_OPTIONAL))
 498                         {
 499                                 exfat_error("unknown entry type %#hhx", entry->type);
 500                                 goto error;
 501                         }
 502                         /* optional entry, warn and skip */
 503                         exfat_warn("unknown entry type %#hhx", entry->type);
 504                         if (continuations == 0)
 505                         {
 506                                 exfat_error("unexpected continuation");
 507                                 goto error;
 508                         }
 509                         --continuations;
 510                         break;
 511                 }
 512
 513                 if (!fetch_next_entry(ef, parent, it))
 514                         goto error;
 515         }
 516         /* we never reach here */
 517
 518 error:
 519         free(*node);
 520         *node = NULL;
 521         return rc;
 522 }
 523
 524 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 525 {
 526         struct iterator it;
 527         int rc;
 528         struct exfat_node* node;
 529         struct exfat_node* current = NULL;
 530
 531         if (dir->flags & EXFAT_ATTRIB_CACHED)
 532                 return 0; /* already cached */
 533
 534         rc = opendir(ef, dir, &it);
 535         if (rc != 0)
 536                 return rc;
 537         while ((rc = readdir(ef, dir, &node, &it)) == 0)
 538         {
 539                 node->parent = dir;
 540                 if (current != NULL)
 541                 {
 542                         current->next = node;
 543                         node->prev = current;
 544                 }
 545                 else
 546                         dir->child = node;
 547
 548                 current = node;
 549         }
 550         closedir(&it);
 551
 552         if (rc != -ENOENT)
 553         {
 554                 /* rollback */
 555                 for (current = dir->child; current; current = node)
 556                 {
 557                         node = current->next;
 558                         free(current);
 559                 }
 560                 dir->child = NULL;
 561                 return rc;
 562         }
 563
 564         dir->flags |= EXFAT_ATTRIB_CACHED;
 565         return 0;
 566 }
 567
 568 static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
 569 {
 570         node->parent = dir;
 571         if (dir->child)
 572         {
 573                 dir->child->prev = node;
 574                 node->next = dir->child;
 575         }
 576         dir->child = node;
 577 }
 578
 579 static void tree_detach(struct exfat_node* node)
 580 {
 581         if (node->prev)
 582                 node->prev->next = node->next;
 583         else /* this is the first node in the list */
 584                 node->parent->child = node->next;
 585         if (node->next)
 586                 node->next->prev = node->prev;
 587         node->parent = NULL;
 588         node->prev = NULL;
 589         node->next = NULL;
 590 }
 591
 592 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 593 {
 594         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 595
 596         while (node->child)
 597         {
 598                 struct exfat_node* p = node->child;
 599                 reset_cache(ef, p);
 600                 tree_detach(p);
 601                 free(p);
 602         }
 603         node->flags &= ~EXFAT_ATTRIB_CACHED;
 604         if (node->references != 0)
 605         {
 606                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 607                 exfat_warn("non-zero reference counter (%d) for '%s'",
 608                                 node->references, buffer);
 609         }
 610         if (node != ef->root && (node->flags & EXFAT_ATTRIB_DIRTY))
 611         {
 612                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 613                 exfat_bug("node '%s' is dirty", buffer);
 614         }
 615         while (node->references)
 616                 exfat_put_node(ef, node);
 617 }
 618
 619 void exfat_reset_cache(struct exfat* ef)
 620 {
 621         reset_cache(ef, ef->root);
 622 }
 623
 624 static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 625                 cluster_t* cluster, off_t* offset)
 626 {
 627         *offset += sizeof(struct exfat_entry);
 628         if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
 629         {
 630                 *cluster = exfat_next_cluster(ef, parent, *cluster);
 631                 if (CLUSTER_INVALID(*cluster))
 632                 {
 633                         exfat_error("invalid cluster %#x while getting next entry",
 634                                         *cluster);
 635                         return false;
 636                 }
 637         }
 638         return true;
 639 }
 640
 641 int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 642 {
 643         cluster_t cluster;
 644         off_t offset;
 645         off_t meta1_offset, meta2_offset;
 646         struct exfat_entry_meta1 meta1;
 647         struct exfat_entry_meta2 meta2;
 648
 649         if (!(node->flags & EXFAT_ATTRIB_DIRTY))
 650                 return 0; /* no need to flush */
 651
 652         if (ef->ro)
 653                 exfat_bug("unable to flush node to read-only FS");
 654
 655         if (node->parent == NULL)
 656                 return 0; /* do not flush unlinked node */
 657
 658         cluster = node->entry_cluster;
 659         offset = node->entry_offset;
 660         meta1_offset = co2o(ef, cluster, offset);
 661         if (!next_entry(ef, node->parent, &cluster, &offset))
 662                 return -EIO;
 663         meta2_offset = co2o(ef, cluster, offset);
 664
 665         if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 666         {
 667                 exfat_error("failed to read meta1 entry on flush");
 668                 return -EIO;
 669         }
 670         if (meta1.type != EXFAT_ENTRY_FILE)
 671                 exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
 672         meta1.attrib = cpu_to_le16(node->flags);
 673         exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 674         exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 675
 676         if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 677         {
 678                 exfat_error("failed to read meta2 entry on flush");
 679                 return -EIO;
 680         }
 681         if (meta2.type != EXFAT_ENTRY_FILE_INFO)
 682                 exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
 683         meta2.size = meta2.valid_size = cpu_to_le64(node->size);
 684         meta2.start_cluster = cpu_to_le32(node->start_cluster);
 685         meta2.flags = EXFAT_FLAG_ALWAYS1;
 686         /* empty files must not be marked as contiguous */
 687         if (node->size != 0 && IS_CONTIGUOUS(*node))
 688                 meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 689         /* name hash remains unchanged, no need to recalculate it */
 690
 691         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 692
 693         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 694         {
 695                 exfat_error("failed to write meta1 entry on flush");
 696                 return -EIO;
 697         }
 698         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 699         {
 700                 exfat_error("failed to write meta2 entry on flush");
 701                 return -EIO;
 702         }
 703
 704         node->flags &= ~EXFAT_ATTRIB_DIRTY;
 705         return exfat_flush(ef);
 706 }
 707
 708 static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 709 {
 710         cluster_t cluster = node->entry_cluster;
 711         off_t offset = node->entry_offset;
 712         int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
 713         uint8_t entry_type;
 714
 715         entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
 716         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 717         {
 718                 exfat_error("failed to erase meta1 entry");
 719                 return false;
 720         }
 721
 722         if (!next_entry(ef, node->parent, &cluster, &offset))
 723                 return false;
 724         entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
 725         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 726         {
 727                 exfat_error("failed to erase meta2 entry");
 728                 return false;
 729         }
 730
 731         while (name_entries--)
 732         {
 733                 if (!next_entry(ef, node->parent, &cluster, &offset))
 734                         return false;
 735                 entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
 736                 if (exfat_pwrite(ef->dev, &entry_type, 1,
 737                                 co2o(ef, cluster, offset)) < 0)
 738                 {
 739                         exfat_error("failed to erase name entry");
 740                         return false;
 741                 }
 742         }
 743         return true;
 744 }
 745
 746 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 747                 off_t deleted_offset)
 748 {
 749         const struct exfat_node* node;
 750         const struct exfat_node* last_node;
 751         uint64_t entries = 0;
 752         uint64_t new_size;
 753
 754         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 755                 exfat_bug("attempted to shrink a file");
 756         if (!(dir->flags & EXFAT_ATTRIB_CACHED))
 757                 exfat_bug("attempted to shrink uncached directory");
 758
 759         for (last_node = node = dir->child; node; node = node->next)
 760         {
 761                 if (deleted_offset < node->entry_offset)
 762                 {
 763                         /* there are other entries after the removed one, no way to shrink
 764                            this directory */
 765                         return 0;
 766                 }
 767                 if (last_node->entry_offset < node->entry_offset)
 768                         last_node = node;
 769         }
 770
 771         if (last_node)
 772         {
 773                 /* offset of the last entry */
 774                 entries += last_node->entry_offset / sizeof(struct exfat_entry);
 775                 /* two subentries with meta info */
 776                 entries += 2;
 777                 /* subentries with file name */
 778                 entries += DIV_ROUND_UP(utf16_length(last_node->name),
 779                                 EXFAT_ENAME_MAX);
 780         }
 781
 782         new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
 783                                  CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
 784         if (new_size == 0) /* directory always has at least 1 cluster */
 785                 new_size = CLUSTER_SIZE(*ef->sb);
 786         if (new_size == dir->size)
 787                 return 0;
 788         return exfat_truncate(ef, dir, new_size, true);
 789 }
 790
 791 static int delete(struct exfat* ef, struct exfat_node* node)
 792 {
 793         struct exfat_node* parent = node->parent;
 794         off_t deleted_offset = node->entry_offset;
 795         int rc;
 796
 797         exfat_get_node(parent);
 798         if (!erase_entry(ef, node))
 799         {
 800                 exfat_put_node(ef, parent);
 801                 return -EIO;
 802         }
 803         exfat_update_mtime(parent);
 804         tree_detach(node);
 805         rc = shrink_directory(ef, parent, deleted_offset);
 806         node->flags |= EXFAT_ATTRIB_UNLINKED;
 807         if (rc != 0)
 808         {
 809                 exfat_flush_node(ef, parent);
 810                 exfat_put_node(ef, parent);
 811                 return rc;
 812         }
 813         rc = exfat_flush_node(ef, parent);
 814         exfat_put_node(ef, parent);
 815         return rc;
 816 }
 817
 818 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 819 {
 820         if (node->flags & EXFAT_ATTRIB_DIR)
 821                 return -EISDIR;
 822         return delete(ef, node);
 823 }
 824
 825 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 826 {
 827         int rc;
 828
 829         if (!(node->flags & EXFAT_ATTRIB_DIR))
 830                 return -ENOTDIR;
 831         /* check that directory is empty */
 832         rc = exfat_cache_directory(ef, node);
 833         if (rc != 0)
 834                 return rc;
 835         if (node->child)
 836                 return -ENOTEMPTY;
 837         return delete(ef, node);
 838 }
 839
 840 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 841                 uint64_t asize, uint32_t difference)
 842 {
 843         return exfat_truncate(ef, dir,
 844                         DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
 845                                 * CLUSTER_SIZE(*ef->sb), true);
 846 }
 847
 848 static int find_slot(struct exfat* ef, struct exfat_node* dir,
 849                 cluster_t* cluster, off_t* offset, int subentries)
 850 {
 851         struct iterator it;
 852         int rc;
 853         const struct exfat_entry* entry;
 854         int contiguous = 0;
 855
 856         rc = opendir(ef, dir, &it);
 857         if (rc != 0)
 858                 return rc;
 859         for (;;)
 860         {
 861                 if (contiguous == 0)
 862                 {
 863                         *cluster = it.cluster;
 864                         *offset = it.offset;
 865                 }
 866                 entry = get_entry_ptr(ef, &it);
 867                 if (entry->type & EXFAT_ENTRY_VALID)
 868                         contiguous = 0;
 869                 else
 870                         contiguous++;
 871                 if (contiguous == subentries)
 872                         break;  /* suitable slot is found */
 873                 if (it.offset + sizeof(struct exfat_entry) >= dir->size)
 874                 {
 875                         rc = grow_directory(ef, dir, dir->size,
 876                                         (subentries - contiguous) * sizeof(struct exfat_entry));
 877                         if (rc != 0)
 878                         {
 879                                 closedir(&it);
 880                                 return rc;
 881                         }
 882                 }
 883                 if (!fetch_next_entry(ef, dir, &it))
 884                 {
 885                         closedir(&it);
 886                         return -EIO;
 887                 }
 888         }
 889         closedir(&it);
 890         return 0;
 891 }
 892
 893 static int write_entry(struct exfat* ef, struct exfat_node* dir,
 894                 const le16_t* name, cluster_t cluster, off_t offset, uint16_t attrib)
 895 {
 896         struct exfat_node* node;
 897         struct exfat_entry_meta1 meta1;
 898         struct exfat_entry_meta2 meta2;
 899         const size_t name_length = utf16_length(name);
 900         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 901         int i;
 902
 903         node = allocate_node();
 904         if (node == NULL)
 905                 return -ENOMEM;
 906         node->entry_cluster = cluster;
 907         node->entry_offset = offset;
 908         memcpy(node->name, name, name_length * sizeof(le16_t));
 909
 910         memset(&meta1, 0, sizeof(meta1));
 911         meta1.type = EXFAT_ENTRY_FILE;
 912         meta1.continuations = 1 + name_entries;
 913         meta1.attrib = cpu_to_le16(attrib);
 914         exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
 915                         &meta1.crtime_cs);
 916         meta1.adate = meta1.mdate = meta1.crdate;
 917         meta1.atime = meta1.mtime = meta1.crtime;
 918         meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 919
 920         memset(&meta2, 0, sizeof(meta2));
 921         meta2.type = EXFAT_ENTRY_FILE_INFO;
 922         meta2.flags = EXFAT_FLAG_ALWAYS1;
 923         meta2.name_length = name_length;
 924         meta2.name_hash = exfat_calc_name_hash(ef, node->name);
 925         meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
 926
 927         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 928
 929         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 930                         co2o(ef, cluster, offset)) < 0)
 931         {
 932                 exfat_error("failed to write meta1 entry");
 933                 return -EIO;
 934         }
 935         if (!next_entry(ef, dir, &cluster, &offset))
 936                 return -EIO;
 937         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 938                         co2o(ef, cluster, offset)) < 0)
 939         {
 940                 exfat_error("failed to write meta2 entry");
 941                 return -EIO;
 942         }
 943         for (i = 0; i < name_entries; i++)
 944         {
 945                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 946                 memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
 947                                 MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
 948                                 sizeof(le16_t));
 949                 if (!next_entry(ef, dir, &cluster, &offset))
 950                         return -EIO;
 951                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 952                                 co2o(ef, cluster, offset)) < 0)
 953                 {
 954                         exfat_error("failed to write name entry");
 955                         return -EIO;
 956                 }
 957         }
 958
 959         init_node_meta1(node, &meta1);
 960         init_node_meta2(node, &meta2);
 961
 962         tree_attach(dir, node);
 963         exfat_update_mtime(dir);
 964         return 0;
 965 }
 966
 967 static int create(struct exfat* ef, const char* path, uint16_t attrib)
 968 {
 969         struct exfat_node* dir;
 970         struct exfat_node* existing;
 971         cluster_t cluster = EXFAT_CLUSTER_BAD;
 972         off_t offset = -1;
 973         le16_t name[EXFAT_NAME_MAX + 1];
 974         int rc;
 975
 976         rc = exfat_split(ef, &dir, &existing, name, path);
 977         if (rc != 0)
 978                 return rc;
 979         if (existing != NULL)
 980         {
 981                 exfat_put_node(ef, existing);
 982                 exfat_put_node(ef, dir);
 983                 return -EEXIST;
 984         }
 985
 986         rc = find_slot(ef, dir, &cluster, &offset,
 987                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
 988         if (rc != 0)
 989         {
 990                 exfat_put_node(ef, dir);
 991                 return rc;
 992         }
 993         rc = write_entry(ef, dir, name, cluster, offset, attrib);
 994         if (rc != 0)
 995         {
 996                 exfat_put_node(ef, dir);
 997                 return rc;
 998         }
 999         rc = exfat_flush_node(ef, dir);
1000         exfat_put_node(ef, dir);
1001         return rc;
1002 }
1003
1004 int exfat_mknod(struct exfat* ef, const char* path)
1005 {
1006         return create(ef, path, EXFAT_ATTRIB_ARCH);
1007 }
1008
1009 int exfat_mkdir(struct exfat* ef, const char* path)
1010 {
1011         int rc;
1012         struct exfat_node* node;
1013
1014         rc = create(ef, path, EXFAT_ATTRIB_DIR);
1015         if (rc != 0)
1016                 return rc;
1017         rc = exfat_lookup(ef, &node, path);
1018         if (rc != 0)
1019                 return 0;
1020         /* directories always have at least one cluster */
1021         rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
1022         if (rc != 0)
1023         {
1024                 delete(ef, node);
1025                 exfat_put_node(ef, node);
1026                 return rc;
1027         }
1028         rc = exfat_flush_node(ef, node);
1029         if (rc != 0)
1030         {
1031                 delete(ef, node);
1032                 exfat_put_node(ef, node);
1033                 return rc;
1034         }
1035         exfat_put_node(ef, node);
1036         return 0;
1037 }
1038
1039 static int rename_entry(struct exfat* ef, struct exfat_node* dir,
1040                 struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
1041                 off_t new_offset)
1042 {
1043         struct exfat_entry_meta1 meta1;
1044         struct exfat_entry_meta2 meta2;
1045         cluster_t old_cluster = node->entry_cluster;
1046         off_t old_offset = node->entry_offset;
1047         const size_t name_length = utf16_length(name);
1048         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
1049         int i;
1050
1051         if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
1052                         co2o(ef, old_cluster, old_offset)) < 0)
1053         {
1054                 exfat_error("failed to read meta1 entry on rename");
1055                 return -EIO;
1056         }
1057         if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
1058                 return -EIO;
1059         if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
1060                         co2o(ef, old_cluster, old_offset)) < 0)
1061         {
1062                 exfat_error("failed to read meta2 entry on rename");
1063                 return -EIO;
1064         }
1065         meta1.continuations = 1 + name_entries;
1066         meta2.name_hash = exfat_calc_name_hash(ef, name);
1067         meta2.name_length = name_length;
1068         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
1069
1070         if (!erase_entry(ef, node))
1071                 return -EIO;
1072
1073         node->entry_cluster = new_cluster;
1074         node->entry_offset = new_offset;
1075
1076         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
1077                         co2o(ef, new_cluster, new_offset)) < 0)
1078         {
1079                 exfat_error("failed to write meta1 entry on rename");
1080                 return -EIO;
1081         }
1082         if (!next_entry(ef, dir, &new_cluster, &new_offset))
1083                 return -EIO;
1084         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
1085                         co2o(ef, new_cluster, new_offset)) < 0)
1086         {
1087                 exfat_error("failed to write meta2 entry on rename");
1088                 return -EIO;
1089         }
1090
1091         for (i = 0; i < name_entries; i++)
1092         {
1093                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
1094                 memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
1095                                 EXFAT_ENAME_MAX * sizeof(le16_t));
1096                 if (!next_entry(ef, dir, &new_cluster, &new_offset))
1097                         return -EIO;
1098                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
1099                                 co2o(ef, new_cluster, new_offset)) < 0)
1100                 {
1101                         exfat_error("failed to write name entry on rename");
1102                         return -EIO;
1103                 }
1104         }
1105
1106         memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
1107         tree_detach(node);
1108         tree_attach(dir, node);
1109         return 0;
1110 }
1111
1112 int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
1113 {
1114         struct exfat_node* node;
1115         struct exfat_node* existing;
1116         struct exfat_node* dir;
1117         cluster_t cluster = EXFAT_CLUSTER_BAD;
1118         off_t offset = -1;
1119         le16_t name[EXFAT_NAME_MAX + 1];
1120         int rc;
1121
1122         rc = exfat_lookup(ef, &node, old_path);
1123         if (rc != 0)
1124                 return rc;
1125
1126         rc = exfat_split(ef, &dir, &existing, name, new_path);
1127         if (rc != 0)
1128         {
1129                 exfat_put_node(ef, node);
1130                 return rc;
1131         }
1132
1133         /* check that target is not a subdirectory of the source */
1134         if (node->flags & EXFAT_ATTRIB_DIR)
1135         {
1136                 struct exfat_node* p;
1137
1138                 for (p = dir; p; p = p->parent)
1139                         if (node == p)
1140                         {
1141                                 if (existing != NULL)
1142                                         exfat_put_node(ef, existing);
1143                                 exfat_put_node(ef, dir);
1144                                 exfat_put_node(ef, node);
1145                                 return -EINVAL;
1146                         }
1147         }
1148
1149         if (existing != NULL)
1150         {
1151                 /* remove target if it's not the same node as source */
1152                 if (existing != node)
1153                 {
1154                         if (existing->flags & EXFAT_ATTRIB_DIR)
1155                         {
1156                                 if (node->flags & EXFAT_ATTRIB_DIR)
1157                                         rc = exfat_rmdir(ef, existing);
1158                                 else
1159                                         rc = -ENOTDIR;
1160                         }
1161                         else
1162                         {
1163                                 if (!(node->flags & EXFAT_ATTRIB_DIR))
1164                                         rc = exfat_unlink(ef, existing);
1165                                 else
1166                                         rc = -EISDIR;
1167                         }
1168                         exfat_put_node(ef, existing);
1169                         if (rc != 0)
1170                         {
1171                                 /* free clusters even if something went wrong; overwise they
1172                                    will be just lost */
1173                                 exfat_cleanup_node(ef, existing);
1174                                 exfat_put_node(ef, dir);
1175                                 exfat_put_node(ef, node);
1176                                 return rc;
1177                         }
1178                         rc = exfat_cleanup_node(ef, existing);
1179                         if (rc != 0)
1180                         {
1181                                 exfat_put_node(ef, dir);
1182                                 exfat_put_node(ef, node);
1183                                 return rc;
1184                         }
1185                 }
1186                 else
1187                         exfat_put_node(ef, existing);
1188         }
1189
1190         rc = find_slot(ef, dir, &cluster, &offset,
1191                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
1192         if (rc != 0)
1193         {
1194                 exfat_put_node(ef, dir);
1195                 exfat_put_node(ef, node);
1196                 return rc;
1197         }
1198         rc = rename_entry(ef, dir, node, name, cluster, offset);
1199         exfat_put_node(ef, dir);
1200         exfat_put_node(ef, node);
1201         return rc;
1202 }
1203
1204 void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
1205 {
1206         node->atime = tv[0].tv_sec;
1207         node->mtime = tv[1].tv_sec;
1208         node->flags |= EXFAT_ATTRIB_DIRTY;
1209 }
1210
1211 void exfat_update_atime(struct exfat_node* node)
1212 {
1213         node->atime = time(NULL);
1214         node->flags |= EXFAT_ATTRIB_DIRTY;
1215 }
1216
1217 void exfat_update_mtime(struct exfat_node* node)
1218 {
1219         node->mtime = time(NULL);
1220         node->flags |= EXFAT_ATTRIB_DIRTY;
1221 }
1222
1223 const char* exfat_get_label(struct exfat* ef)
1224 {
1225         return ef->label;
1226 }
1227
1228 static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
1229 {
1230         struct iterator it;
1231         int rc;
1232
1233         rc = opendir(ef, ef->root, &it);
1234         if (rc != 0)
1235                 return rc;
1236
1237         for (;;)
1238         {
1239                 if (it.offset >= ef->root->size)
1240                 {
1241                         closedir(&it);
1242                         return -ENOENT;
1243                 }
1244
1245                 if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
1246                 {
1247                         *cluster = it.cluster;
1248                         *offset = it.offset;
1249                         closedir(&it);
1250                         return 0;
1251                 }
1252
1253                 if (!fetch_next_entry(ef, ef->root, &it))
1254                 {
1255                         closedir(&it);
1256                         return -EIO;
1257                 }
1258         }
1259 }
1260
1261 int exfat_set_label(struct exfat* ef, const char* label)
1262 {
1263         le16_t label_utf16[EXFAT_ENAME_MAX + 1];
1264         int rc;
1265         cluster_t cluster;
1266         off_t offset;
1267         struct exfat_entry_label entry;
1268
1269         memset(label_utf16, 0, sizeof(label_utf16));
1270         rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
1271         if (rc != 0)
1272                 return rc;
1273
1274         rc = find_label(ef, &cluster, &offset);
1275         if (rc == -ENOENT)
1276                 rc = find_slot(ef, ef->root, &cluster, &offset, 1);
1277         if (rc != 0)
1278                 return rc;
1279
1280         entry.type = EXFAT_ENTRY_LABEL;
1281         entry.length = utf16_length(label_utf16);
1282         memcpy(entry.name, label_utf16, sizeof(entry.name));
1283         if (entry.length == 0)
1284                 entry.type ^= EXFAT_ENTRY_VALID;
1285
1286         if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
1287                         co2o(ef, cluster, offset)) < 0)
1288         {
1289                 exfat_error("failed to write label entry");
1290                 return -EIO;
1291         }
1292         strcpy(ef->label, label);
1293         return 0;
1294 }