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         char* chunk;
  34 };
  35
  36 struct exfat_node* exfat_get_node(struct exfat_node* node)
  37 {
  38         /* if we switch to multi-threaded mode we will need atomic
  39            increment here and atomic decrement in exfat_put_node() */
  40         node->references++;
  41         return node;
  42 }
  43
  44 void exfat_put_node(struct exfat* ef, struct exfat_node* node)
  45 {
  46         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
  47
  48         --node->references;
  49         if (node->references < 0)
  50         {
  51                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
  52                 exfat_bug("reference counter of '%s' is below zero", buffer);
  53         }
  54         else if (node->references == 0 && node != ef->root)
  55         {
  56                 if (node->flags & EXFAT_ATTRIB_DIRTY)
  57                 {
  58                         exfat_get_name(node, buffer, sizeof(buffer) - 1);
  59                         exfat_warn("dirty node '%s' with zero references", buffer);
  60                 }
  61         }
  62 }
  63
  64 /**
  65  * This function must be called on rmdir and unlink (after the last
  66  * exfat_put_node()) to free clusters.
  67  */
  68 int exfat_cleanup_node(struct exfat* ef, struct exfat_node* node)
  69 {
  70         int rc = 0;
  71
  72         if (node->references != 0)
  73                 exfat_bug("unable to cleanup a node with %d references",
  74                                 node->references);
  75
  76         if (node->flags & EXFAT_ATTRIB_UNLINKED)
  77         {
  78                 /* free all clusters and node structure itself */
  79                 rc = exfat_truncate(ef, node, 0, true);
  80                 /* free the node even in case of error or its memory will be lost */
  81                 free(node);
  82         }
  83         return rc;
  84 }
  85
  86 /**
  87  * Cluster + offset from the beginning of the directory to absolute offset.
  88  */
  89 static off_t co2o(struct exfat* ef, cluster_t cluster, off_t offset)
  90 {
  91         return exfat_c2o(ef, cluster) + offset % CLUSTER_SIZE(*ef->sb);
  92 }
  93
  94 static int opendir(struct exfat* ef, const struct exfat_node* dir,
  95                 struct iterator* it)
  96 {
  97         if (!(dir->flags & EXFAT_ATTRIB_DIR))
  98                 exfat_bug("not a directory");
  99         it->cluster = dir->start_cluster;
 100         it->offset = 0;
 101         it->chunk = malloc(CLUSTER_SIZE(*ef->sb));
 102         if (it->chunk == NULL)
 103         {
 104                 exfat_error("out of memory");
 105                 return -ENOMEM;
 106         }
 107         if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 108                         exfat_c2o(ef, it->cluster)) < 0)
 109         {
 110                 free(it->chunk);
 111                 exfat_error("failed to read directory cluster %#x", it->cluster);
 112                 return -EIO;
 113         }
 114         return 0;
 115 }
 116
 117 static void closedir(struct iterator* it)
 118 {
 119         it->cluster = 0;
 120         it->offset = 0;
 121         free(it->chunk);
 122         it->chunk = NULL;
 123 }
 124
 125 static bool fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 126                 struct iterator* it)
 127 {
 128         /* move iterator to the next entry in the directory */
 129         it->offset += sizeof(struct exfat_entry);
 130         /* fetch the next cluster if needed */
 131         if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
 132         {
 133                 /* reached the end of directory; the caller should check this
 134                    condition too */
 135                 if (it->offset >= parent->size)
 136                         return true;
 137                 it->cluster = exfat_next_cluster(ef, parent, it->cluster);
 138                 if (CLUSTER_INVALID(it->cluster))
 139                 {
 140                         exfat_error("invalid cluster 0x%x while reading directory",
 141                                         it->cluster);
 142                         return false;
 143                 }
 144                 if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 145                                 exfat_c2o(ef, it->cluster)) < 0)
 146                 {
 147                         exfat_error("failed to read the next directory cluster %#x",
 148                                         it->cluster);
 149                         return false;
 150                 }
 151         }
 152         return true;
 153 }
 154
 155 static struct exfat_node* allocate_node(void)
 156 {
 157         struct exfat_node* node = malloc(sizeof(struct exfat_node));
 158         if (node == NULL)
 159         {
 160                 exfat_error("failed to allocate node");
 161                 return NULL;
 162         }
 163         memset(node, 0, sizeof(struct exfat_node));
 164         return node;
 165 }
 166
 167 static void init_node_meta1(struct exfat_node* node,
 168                 const struct exfat_entry_meta1* meta1)
 169 {
 170         node->flags = le16_to_cpu(meta1->attrib);
 171         node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
 172                         meta1->mtime_cs);
 173         /* there is no centiseconds field for atime */
 174         node->atime = exfat_exfat2unix(meta1->adate, meta1->atime, 0);
 175 }
 176
 177 static void init_node_meta2(struct exfat_node* node,
 178                 const struct exfat_entry_meta2* meta2)
 179 {
 180         node->size = le64_to_cpu(meta2->size);
 181         node->start_cluster = le32_to_cpu(meta2->start_cluster);
 182         node->fptr_cluster = node->start_cluster;
 183         if (meta2->flags & EXFAT_FLAG_CONTIGUOUS)
 184                 node->flags |= EXFAT_ATTRIB_CONTIGUOUS;
 185 }
 186
 187 static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
 188                 const struct iterator* it)
 189 {
 190         return (const struct exfat_entry*)
 191                         (it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
 192 }
 193
 194 static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
 195                 uint16_t reference_checksum, uint64_t valid_size)
 196 {
 197         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 198
 199         /*
 200            Validate checksum first. If it's invalid all other fields probably
 201            contain just garbage.
 202         */
 203         if (actual_checksum != reference_checksum)
 204         {
 205                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 206                 exfat_error("'%s' has invalid checksum (%#hx != %#hx)", buffer,
 207                                 actual_checksum, reference_checksum);
 208                 return false;
 209         }
 210
 211         /*
 212            exFAT does not support sparse files but allows files with uninitialized
 213            clusters. For such files valid_size means initialized data size and
 214            cannot be greater than file size. See SetFileValidData() function
 215            description in MSDN.
 216         */
 217         if (valid_size > node->size)
 218         {
 219                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 220                 exfat_error("'%s' has valid size (%"PRIu64") greater than size "
 221                                 "(%"PRIu64")", buffer, valid_size, node->size);
 222                 return false;
 223         }
 224
 225         return true;
 226 }
 227
 228 static void decompress_upcase(uint16_t* output, const le16_t* source,
 229                 size_t size)
 230 {
 231         size_t si;
 232         size_t oi;
 233
 234         for (oi = 0; oi < EXFAT_UPCASE_CHARS; oi++)
 235                 output[oi] = oi;
 236
 237         for (si = 0, oi = 0; si < size && oi < EXFAT_UPCASE_CHARS; si++)
 238         {
 239                 uint16_t ch = le16_to_cpu(source[si]);
 240
 241                 if (ch == 0xffff && si + 1 < size)      /* indicates a run */
 242                         oi += le16_to_cpu(source[++si]);
 243                 else
 244                         output[oi++] = ch;
 245         }
 246 }
 247
 248 /*
 249  * Reads one entry in directory at position pointed by iterator and fills
 250  * node structure.
 251  */
 252 static int readdir(struct exfat* ef, const struct exfat_node* parent,
 253                 struct exfat_node** node, struct iterator* it)
 254 {
 255         int rc = -EIO;
 256         const struct exfat_entry* entry;
 257         const struct exfat_entry_meta1* meta1;
 258         const struct exfat_entry_meta2* meta2;
 259         const struct exfat_entry_name* file_name;
 260         const struct exfat_entry_upcase* upcase;
 261         const struct exfat_entry_bitmap* bitmap;
 262         const struct exfat_entry_label* label;
 263         uint8_t continuations = 0;
 264         le16_t* namep = NULL;
 265         uint16_t reference_checksum = 0;
 266         uint16_t actual_checksum = 0;
 267         uint64_t valid_size = 0;
 268         uint64_t upcase_size = 0;
 269         le16_t* upcase_comp = NULL;
 270
 271         *node = NULL;
 272
 273         for (;;)
 274         {
 275                 if (it->offset >= parent->size)
 276                 {
 277                         if (continuations != 0)
 278                         {
 279                                 exfat_error("expected %hhu continuations", continuations);
 280                                 goto error;
 281                         }
 282                         return -ENOENT; /* that's OK, means end of directory */
 283                 }
 284
 285                 entry = get_entry_ptr(ef, it);
 286                 switch (entry->type)
 287                 {
 288                 case EXFAT_ENTRY_FILE:
 289                         if (continuations != 0)
 290                         {
 291                                 exfat_error("expected %hhu continuations before new entry",
 292                                                 continuations);
 293                                 goto error;
 294                         }
 295                         meta1 = (const struct exfat_entry_meta1*) entry;
 296                         continuations = meta1->continuations;
 297                         /* each file entry must have at least 2 continuations:
 298                            info and name */
 299                         if (continuations < 2)
 300                         {
 301                                 exfat_error("too few continuations (%hhu)", continuations);
 302                                 goto error;
 303                         }
 304                         if (continuations > 1 +
 305                                         DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
 306                         {
 307                                 exfat_error("too many continuations (%hhu)", continuations);
 308                                 goto error;
 309                         }
 310                         reference_checksum = le16_to_cpu(meta1->checksum);
 311                         actual_checksum = exfat_start_checksum(meta1);
 312                         *node = allocate_node();
 313                         if (*node == NULL)
 314                         {
 315                                 rc = -ENOMEM;
 316                                 goto error;
 317                         }
 318                         /* new node has zero reference counter */
 319                         (*node)->entry_cluster = it->cluster;
 320                         (*node)->entry_offset = it->offset;
 321                         init_node_meta1(*node, meta1);
 322                         namep = (*node)->name;
 323                         break;
 324
 325                 case EXFAT_ENTRY_FILE_INFO:
 326                         if (continuations < 2)
 327                         {
 328                                 exfat_error("unexpected continuation (%hhu)",
 329                                                 continuations);
 330                                 goto error;
 331                         }
 332                         meta2 = (const struct exfat_entry_meta2*) entry;
 333                         if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
 334                         {
 335                                 exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
 336                                 goto error;
 337                         }
 338                         init_node_meta2(*node, meta2);
 339                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 340                         valid_size = le64_to_cpu(meta2->valid_size);
 341                         /* empty files must be marked as non-contiguous */
 342                         if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
 343                         {
 344                                 exfat_error("empty file marked as contiguous (0x%hhx)",
 345                                                 meta2->flags);
 346                                 goto error;
 347                         }
 348                         /* directories must be aligned on at cluster boundary */
 349                         if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
 350                                 (*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
 351                         {
 352                                 exfat_error("directory has invalid size %"PRIu64" bytes",
 353                                                 (*node)->size);
 354                                 goto error;
 355                         }
 356                         --continuations;
 357                         break;
 358
 359                 case EXFAT_ENTRY_FILE_NAME:
 360                         if (continuations == 0)
 361                         {
 362                                 exfat_error("unexpected continuation");
 363                                 goto error;
 364                         }
 365                         file_name = (const struct exfat_entry_name*) entry;
 366                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 367
 368                         memcpy(namep, file_name->name,
 369                                         MIN(EXFAT_ENAME_MAX,
 370                                                 ((*node)->name + EXFAT_NAME_MAX - namep)) *
 371                                         sizeof(le16_t));
 372                         namep += EXFAT_ENAME_MAX;
 373                         if (--continuations == 0)
 374                         {
 375                                 if (!check_node(*node, actual_checksum, reference_checksum,
 376                                                 valid_size))
 377                                         goto error;
 378                                 if (!fetch_next_entry(ef, parent, it))
 379                                         goto error;
 380                                 return 0; /* entry completed */
 381                         }
 382                         break;
 383
 384                 case EXFAT_ENTRY_UPCASE:
 385                         if (ef->upcase != NULL)
 386                                 break;
 387                         upcase = (const struct exfat_entry_upcase*) entry;
 388                         if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
 389                         {
 390                                 exfat_error("invalid cluster 0x%x in upcase table",
 391                                                 le32_to_cpu(upcase->start_cluster));
 392                                 goto error;
 393                         }
 394                         upcase_size = le64_to_cpu(upcase->size);
 395                         if (upcase_size == 0 ||
 396                                 upcase_size > EXFAT_UPCASE_CHARS * sizeof(uint16_t) ||
 397                                 upcase_size % sizeof(uint16_t) != 0)
 398                         {
 399                                 exfat_error("bad upcase table size (%"PRIu64" bytes)",
 400                                                 upcase_size);
 401                                 goto error;
 402                         }
 403                         upcase_comp = malloc(upcase_size);
 404                         if (upcase_comp == NULL)
 405                         {
 406                                 exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
 407                                                 upcase_size);
 408                                 rc = -ENOMEM;
 409                                 goto error;
 410                         }
 411
 412                         /* read compressed upcase table */
 413                         if (exfat_pread(ef->dev, upcase_comp, upcase_size,
 414                                         exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 415                         {
 416                                 free(upcase_comp);
 417                                 exfat_error("failed to read upper case table "
 418                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 419                                                 upcase_size,
 420                                                 le32_to_cpu(upcase->start_cluster));
 421                                 goto error;
 422                         }
 423
 424                         /* decompress upcase table */
 425                         ef->upcase = calloc(EXFAT_UPCASE_CHARS, sizeof(uint16_t));
 426                         if (ef->upcase == NULL)
 427                         {
 428                                 free(upcase_comp);
 429                                 exfat_error("failed to allocate decompressed upcase table");
 430                                 rc = -ENOMEM;
 431                                 goto error;
 432                         }
 433                         decompress_upcase(ef->upcase, upcase_comp,
 434                                         upcase_size / sizeof(uint16_t));
 435                         free(upcase_comp);
 436                         break;
 437
 438                 case EXFAT_ENTRY_BITMAP:
 439                         bitmap = (const struct exfat_entry_bitmap*) entry;
 440                         ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
 441                         if (CLUSTER_INVALID(ef->cmap.start_cluster))
 442                         {
 443                                 exfat_error("invalid cluster 0x%x in clusters bitmap",
 444                                                 ef->cmap.start_cluster);
 445                                 goto error;
 446                         }
 447                         ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 448                                 EXFAT_FIRST_DATA_CLUSTER;
 449                         if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 450                         {
 451                                 exfat_error("invalid clusters bitmap size: %"PRIu64
 452                                                 " (expected at least %u)",
 453                                                 le64_to_cpu(bitmap->size),
 454                                                 DIV_ROUND_UP(ef->cmap.size, 8));
 455                                 goto error;
 456                         }
 457                         /* FIXME bitmap can be rather big, up to 512 MB */
 458                         ef->cmap.chunk_size = ef->cmap.size;
 459                         ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 460                         if (ef->cmap.chunk == NULL)
 461                         {
 462                                 exfat_error("failed to allocate clusters bitmap chunk "
 463                                                 "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
 464                                 rc = -ENOMEM;
 465                                 goto error;
 466                         }
 467
 468                         if (exfat_pread(ef->dev, ef->cmap.chunk,
 469                                         BMAP_SIZE(ef->cmap.chunk_size),
 470                                         exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
 471                         {
 472                                 exfat_error("failed to read clusters bitmap "
 473                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 474                                                 le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
 475                                 goto error;
 476                         }
 477                         break;
 478
 479                 case EXFAT_ENTRY_LABEL:
 480                         label = (const struct exfat_entry_label*) entry;
 481                         if (label->length > EXFAT_ENAME_MAX)
 482                         {
 483                                 exfat_error("too long label (%hhu chars)", label->length);
 484                                 goto error;
 485                         }
 486                         if (utf16_to_utf8(ef->label, label->name,
 487                                                 sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
 488                                 goto error;
 489                         break;
 490
 491                 default:
 492                         if (!(entry->type & EXFAT_ENTRY_VALID))
 493                                 break; /* deleted entry, ignore it */
 494                         if (!(entry->type & EXFAT_ENTRY_OPTIONAL))
 495                         {
 496                                 exfat_error("unknown entry type %#hhx", entry->type);
 497                                 goto error;
 498                         }
 499                         /* optional entry, warn and skip */
 500                         exfat_warn("unknown entry type %#hhx", entry->type);
 501                         if (continuations == 0)
 502                         {
 503                                 exfat_error("unexpected continuation");
 504                                 goto error;
 505                         }
 506                         --continuations;
 507                         break;
 508                 }
 509
 510                 if (!fetch_next_entry(ef, parent, it))
 511                         goto error;
 512         }
 513         /* we never reach here */
 514
 515 error:
 516         free(*node);
 517         *node = NULL;
 518         return rc;
 519 }
 520
 521 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 522 {
 523         struct iterator it;
 524         int rc;
 525         struct exfat_node* node;
 526         struct exfat_node* current = NULL;
 527
 528         if (dir->flags & EXFAT_ATTRIB_CACHED)
 529                 return 0; /* already cached */
 530
 531         rc = opendir(ef, dir, &it);
 532         if (rc != 0)
 533                 return rc;
 534         while ((rc = readdir(ef, dir, &node, &it)) == 0)
 535         {
 536                 node->parent = dir;
 537                 if (current != NULL)
 538                 {
 539                         current->next = node;
 540                         node->prev = current;
 541                 }
 542                 else
 543                         dir->child = node;
 544
 545                 current = node;
 546         }
 547         closedir(&it);
 548
 549         if (rc != -ENOENT)
 550         {
 551                 /* rollback */
 552                 for (current = dir->child; current; current = node)
 553                 {
 554                         node = current->next;
 555                         free(current);
 556                 }
 557                 dir->child = NULL;
 558                 return rc;
 559         }
 560
 561         dir->flags |= EXFAT_ATTRIB_CACHED;
 562         return 0;
 563 }
 564
 565 static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
 566 {
 567         node->parent = dir;
 568         if (dir->child)
 569         {
 570                 dir->child->prev = node;
 571                 node->next = dir->child;
 572         }
 573         dir->child = node;
 574 }
 575
 576 static void tree_detach(struct exfat_node* node)
 577 {
 578         if (node->prev)
 579                 node->prev->next = node->next;
 580         else /* this is the first node in the list */
 581                 node->parent->child = node->next;
 582         if (node->next)
 583                 node->next->prev = node->prev;
 584         node->parent = NULL;
 585         node->prev = NULL;
 586         node->next = NULL;
 587 }
 588
 589 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 590 {
 591         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 592
 593         while (node->child)
 594         {
 595                 struct exfat_node* p = node->child;
 596                 reset_cache(ef, p);
 597                 tree_detach(p);
 598                 free(p);
 599         }
 600         node->flags &= ~EXFAT_ATTRIB_CACHED;
 601         if (node->references != 0)
 602         {
 603                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 604                 exfat_warn("non-zero reference counter (%d) for '%s'",
 605                                 node->references, buffer);
 606         }
 607         if (node != ef->root && (node->flags & EXFAT_ATTRIB_DIRTY))
 608         {
 609                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 610                 exfat_bug("node '%s' is dirty", buffer);
 611         }
 612         while (node->references)
 613                 exfat_put_node(ef, node);
 614 }
 615
 616 void exfat_reset_cache(struct exfat* ef)
 617 {
 618         reset_cache(ef, ef->root);
 619 }
 620
 621 static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 622                 cluster_t* cluster, off_t* offset)
 623 {
 624         *offset += sizeof(struct exfat_entry);
 625         if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
 626         {
 627                 *cluster = exfat_next_cluster(ef, parent, *cluster);
 628                 if (CLUSTER_INVALID(*cluster))
 629                 {
 630                         exfat_error("invalid cluster %#x while getting next entry",
 631                                         *cluster);
 632                         return false;
 633                 }
 634         }
 635         return true;
 636 }
 637
 638 int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 639 {
 640         cluster_t cluster;
 641         off_t offset;
 642         off_t meta1_offset, meta2_offset;
 643         struct exfat_entry_meta1 meta1;
 644         struct exfat_entry_meta2 meta2;
 645
 646         if (!(node->flags & EXFAT_ATTRIB_DIRTY))
 647                 return 0; /* no need to flush */
 648
 649         if (ef->ro)
 650                 exfat_bug("unable to flush node to read-only FS");
 651
 652         if (node->parent == NULL)
 653                 return 0; /* do not flush unlinked node */
 654
 655         cluster = node->entry_cluster;
 656         offset = node->entry_offset;
 657         meta1_offset = co2o(ef, cluster, offset);
 658         if (!next_entry(ef, node->parent, &cluster, &offset))
 659                 return -EIO;
 660         meta2_offset = co2o(ef, cluster, offset);
 661
 662         if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 663         {
 664                 exfat_error("failed to read meta1 entry on flush");
 665                 return -EIO;
 666         }
 667         if (meta1.type != EXFAT_ENTRY_FILE)
 668                 exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
 669         meta1.attrib = cpu_to_le16(node->flags);
 670         exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 671         exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 672
 673         if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 674         {
 675                 exfat_error("failed to read meta2 entry on flush");
 676                 return -EIO;
 677         }
 678         if (meta2.type != EXFAT_ENTRY_FILE_INFO)
 679                 exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
 680         meta2.size = meta2.valid_size = cpu_to_le64(node->size);
 681         meta2.start_cluster = cpu_to_le32(node->start_cluster);
 682         meta2.flags = EXFAT_FLAG_ALWAYS1;
 683         /* empty files must not be marked as contiguous */
 684         if (node->size != 0 && IS_CONTIGUOUS(*node))
 685                 meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 686         /* name hash remains unchanged, no need to recalculate it */
 687
 688         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 689
 690         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 691         {
 692                 exfat_error("failed to write meta1 entry on flush");
 693                 return -EIO;
 694         }
 695         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 696         {
 697                 exfat_error("failed to write meta2 entry on flush");
 698                 return -EIO;
 699         }
 700
 701         node->flags &= ~EXFAT_ATTRIB_DIRTY;
 702         return exfat_flush(ef);
 703 }
 704
 705 static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 706 {
 707         cluster_t cluster = node->entry_cluster;
 708         off_t offset = node->entry_offset;
 709         int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
 710         uint8_t entry_type;
 711
 712         entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
 713         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 714         {
 715                 exfat_error("failed to erase meta1 entry");
 716                 return false;
 717         }
 718
 719         if (!next_entry(ef, node->parent, &cluster, &offset))
 720                 return false;
 721         entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
 722         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 723         {
 724                 exfat_error("failed to erase meta2 entry");
 725                 return false;
 726         }
 727
 728         while (name_entries--)
 729         {
 730                 if (!next_entry(ef, node->parent, &cluster, &offset))
 731                         return false;
 732                 entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
 733                 if (exfat_pwrite(ef->dev, &entry_type, 1,
 734                                 co2o(ef, cluster, offset)) < 0)
 735                 {
 736                         exfat_error("failed to erase name entry");
 737                         return false;
 738                 }
 739         }
 740         return true;
 741 }
 742
 743 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 744                 off_t deleted_offset)
 745 {
 746         const struct exfat_node* node;
 747         const struct exfat_node* last_node;
 748         uint64_t entries = 0;
 749         uint64_t new_size;
 750
 751         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 752                 exfat_bug("attempted to shrink a file");
 753         if (!(dir->flags & EXFAT_ATTRIB_CACHED))
 754                 exfat_bug("attempted to shrink uncached directory");
 755
 756         for (last_node = node = dir->child; node; node = node->next)
 757         {
 758                 if (deleted_offset < node->entry_offset)
 759                 {
 760                         /* there are other entries after the removed one, no way to shrink
 761                            this directory */
 762                         return 0;
 763                 }
 764                 if (last_node->entry_offset < node->entry_offset)
 765                         last_node = node;
 766         }
 767
 768         if (last_node)
 769         {
 770                 /* offset of the last entry */
 771                 entries += last_node->entry_offset / sizeof(struct exfat_entry);
 772                 /* two subentries with meta info */
 773                 entries += 2;
 774                 /* subentries with file name */
 775                 entries += DIV_ROUND_UP(utf16_length(last_node->name),
 776                                 EXFAT_ENAME_MAX);
 777         }
 778
 779         new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
 780                                  CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
 781         if (new_size == 0) /* directory always has at least 1 cluster */
 782                 new_size = CLUSTER_SIZE(*ef->sb);
 783         if (new_size == dir->size)
 784                 return 0;
 785         return exfat_truncate(ef, dir, new_size, true);
 786 }
 787
 788 static int delete(struct exfat* ef, struct exfat_node* node)
 789 {
 790         struct exfat_node* parent = node->parent;
 791         off_t deleted_offset = node->entry_offset;
 792         int rc;
 793
 794         exfat_get_node(parent);
 795         if (!erase_entry(ef, node))
 796         {
 797                 exfat_put_node(ef, parent);
 798                 return -EIO;
 799         }
 800         exfat_update_mtime(parent);
 801         tree_detach(node);
 802         rc = shrink_directory(ef, parent, deleted_offset);
 803         node->flags |= EXFAT_ATTRIB_UNLINKED;
 804         if (rc != 0)
 805         {
 806                 exfat_flush_node(ef, parent);
 807                 exfat_put_node(ef, parent);
 808                 return rc;
 809         }
 810         rc = exfat_flush_node(ef, parent);
 811         exfat_put_node(ef, parent);
 812         return rc;
 813 }
 814
 815 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 816 {
 817         if (node->flags & EXFAT_ATTRIB_DIR)
 818                 return -EISDIR;
 819         return delete(ef, node);
 820 }
 821
 822 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 823 {
 824         int rc;
 825
 826         if (!(node->flags & EXFAT_ATTRIB_DIR))
 827                 return -ENOTDIR;
 828         /* check that directory is empty */
 829         rc = exfat_cache_directory(ef, node);
 830         if (rc != 0)
 831                 return rc;
 832         if (node->child)
 833                 return -ENOTEMPTY;
 834         return delete(ef, node);
 835 }
 836
 837 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 838                 uint64_t asize, uint32_t difference)
 839 {
 840         return exfat_truncate(ef, dir,
 841                         DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
 842                                 * CLUSTER_SIZE(*ef->sb), true);
 843 }
 844
 845 static int find_slot(struct exfat* ef, struct exfat_node* dir,
 846                 cluster_t* cluster, off_t* offset, int subentries)
 847 {
 848         struct iterator it;
 849         int rc;
 850         const struct exfat_entry* entry;
 851         int contiguous = 0;
 852
 853         rc = opendir(ef, dir, &it);
 854         if (rc != 0)
 855                 return rc;
 856         for (;;)
 857         {
 858                 if (contiguous == 0)
 859                 {
 860                         *cluster = it.cluster;
 861                         *offset = it.offset;
 862                 }
 863                 entry = get_entry_ptr(ef, &it);
 864                 if (entry->type & EXFAT_ENTRY_VALID)
 865                         contiguous = 0;
 866                 else
 867                         contiguous++;
 868                 if (contiguous == subentries)
 869                         break;  /* suitable slot is found */
 870                 if (it.offset + sizeof(struct exfat_entry) >= dir->size)
 871                 {
 872                         rc = grow_directory(ef, dir, dir->size,
 873                                         (subentries - contiguous) * sizeof(struct exfat_entry));
 874                         if (rc != 0)
 875                         {
 876                                 closedir(&it);
 877                                 return rc;
 878                         }
 879                 }
 880                 if (!fetch_next_entry(ef, dir, &it))
 881                 {
 882                         closedir(&it);
 883                         return -EIO;
 884                 }
 885         }
 886         closedir(&it);
 887         return 0;
 888 }
 889
 890 static int write_entry(struct exfat* ef, struct exfat_node* dir,
 891                 const le16_t* name, cluster_t cluster, off_t offset, uint16_t attrib)
 892 {
 893         struct exfat_node* node;
 894         struct exfat_entry_meta1 meta1;
 895         struct exfat_entry_meta2 meta2;
 896         const size_t name_length = utf16_length(name);
 897         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 898         int i;
 899
 900         node = allocate_node();
 901         if (node == NULL)
 902                 return -ENOMEM;
 903         node->entry_cluster = cluster;
 904         node->entry_offset = offset;
 905         memcpy(node->name, name, name_length * sizeof(le16_t));
 906
 907         memset(&meta1, 0, sizeof(meta1));
 908         meta1.type = EXFAT_ENTRY_FILE;
 909         meta1.continuations = 1 + name_entries;
 910         meta1.attrib = cpu_to_le16(attrib);
 911         exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
 912                         &meta1.crtime_cs);
 913         meta1.adate = meta1.mdate = meta1.crdate;
 914         meta1.atime = meta1.mtime = meta1.crtime;
 915         meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 916
 917         memset(&meta2, 0, sizeof(meta2));
 918         meta2.type = EXFAT_ENTRY_FILE_INFO;
 919         meta2.flags = EXFAT_FLAG_ALWAYS1;
 920         meta2.name_length = name_length;
 921         meta2.name_hash = exfat_calc_name_hash(ef, node->name);
 922         meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
 923
 924         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 925
 926         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 927                         co2o(ef, cluster, offset)) < 0)
 928         {
 929                 exfat_error("failed to write meta1 entry");
 930                 return -EIO;
 931         }
 932         if (!next_entry(ef, dir, &cluster, &offset))
 933                 return -EIO;
 934         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 935                         co2o(ef, cluster, offset)) < 0)
 936         {
 937                 exfat_error("failed to write meta2 entry");
 938                 return -EIO;
 939         }
 940         for (i = 0; i < name_entries; i++)
 941         {
 942                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 943                 memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
 944                                 MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
 945                                 sizeof(le16_t));
 946                 if (!next_entry(ef, dir, &cluster, &offset))
 947                         return -EIO;
 948                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 949                                 co2o(ef, cluster, offset)) < 0)
 950                 {
 951                         exfat_error("failed to write name entry");
 952                         return -EIO;
 953                 }
 954         }
 955
 956         init_node_meta1(node, &meta1);
 957         init_node_meta2(node, &meta2);
 958
 959         tree_attach(dir, node);
 960         exfat_update_mtime(dir);
 961         return 0;
 962 }
 963
 964 static int create(struct exfat* ef, const char* path, uint16_t attrib)
 965 {
 966         struct exfat_node* dir;
 967         struct exfat_node* existing;
 968         cluster_t cluster = EXFAT_CLUSTER_BAD;
 969         off_t offset = -1;
 970         le16_t name[EXFAT_NAME_MAX + 1];
 971         int rc;
 972
 973         rc = exfat_split(ef, &dir, &existing, name, path);
 974         if (rc != 0)
 975                 return rc;
 976         if (existing != NULL)
 977         {
 978                 exfat_put_node(ef, existing);
 979                 exfat_put_node(ef, dir);
 980                 return -EEXIST;
 981         }
 982
 983         rc = find_slot(ef, dir, &cluster, &offset,
 984                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
 985         if (rc != 0)
 986         {
 987                 exfat_put_node(ef, dir);
 988                 return rc;
 989         }
 990         rc = write_entry(ef, dir, name, cluster, offset, attrib);
 991         if (rc != 0)
 992         {
 993                 exfat_put_node(ef, dir);
 994                 return rc;
 995         }
 996         rc = exfat_flush_node(ef, dir);
 997         exfat_put_node(ef, dir);
 998         return rc;
 999 }
1000
1001 int exfat_mknod(struct exfat* ef, const char* path)
1002 {
1003         return create(ef, path, EXFAT_ATTRIB_ARCH);
1004 }
1005
1006 int exfat_mkdir(struct exfat* ef, const char* path)
1007 {
1008         int rc;
1009         struct exfat_node* node;
1010
1011         rc = create(ef, path, EXFAT_ATTRIB_DIR);
1012         if (rc != 0)
1013                 return rc;
1014         rc = exfat_lookup(ef, &node, path);
1015         if (rc != 0)
1016                 return 0;
1017         /* directories always have at least one cluster */
1018         rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
1019         if (rc != 0)
1020         {
1021                 delete(ef, node);
1022                 exfat_put_node(ef, node);
1023                 return rc;
1024         }
1025         rc = exfat_flush_node(ef, node);
1026         if (rc != 0)
1027         {
1028                 delete(ef, node);
1029                 exfat_put_node(ef, node);
1030                 return rc;
1031         }
1032         exfat_put_node(ef, node);
1033         return 0;
1034 }
1035
1036 static int rename_entry(struct exfat* ef, struct exfat_node* dir,
1037                 struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
1038                 off_t new_offset)
1039 {
1040         struct exfat_entry_meta1 meta1;
1041         struct exfat_entry_meta2 meta2;
1042         cluster_t old_cluster = node->entry_cluster;
1043         off_t old_offset = node->entry_offset;
1044         const size_t name_length = utf16_length(name);
1045         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
1046         int i;
1047
1048         if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
1049                         co2o(ef, old_cluster, old_offset)) < 0)
1050         {
1051                 exfat_error("failed to read meta1 entry on rename");
1052                 return -EIO;
1053         }
1054         if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
1055                 return -EIO;
1056         if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
1057                         co2o(ef, old_cluster, old_offset)) < 0)
1058         {
1059                 exfat_error("failed to read meta2 entry on rename");
1060                 return -EIO;
1061         }
1062         meta1.continuations = 1 + name_entries;
1063         meta2.name_hash = exfat_calc_name_hash(ef, name);
1064         meta2.name_length = name_length;
1065         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
1066
1067         if (!erase_entry(ef, node))
1068                 return -EIO;
1069
1070         node->entry_cluster = new_cluster;
1071         node->entry_offset = new_offset;
1072
1073         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
1074                         co2o(ef, new_cluster, new_offset)) < 0)
1075         {
1076                 exfat_error("failed to write meta1 entry on rename");
1077                 return -EIO;
1078         }
1079         if (!next_entry(ef, dir, &new_cluster, &new_offset))
1080                 return -EIO;
1081         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
1082                         co2o(ef, new_cluster, new_offset)) < 0)
1083         {
1084                 exfat_error("failed to write meta2 entry on rename");
1085                 return -EIO;
1086         }
1087
1088         for (i = 0; i < name_entries; i++)
1089         {
1090                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
1091                 memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
1092                                 EXFAT_ENAME_MAX * sizeof(le16_t));
1093                 if (!next_entry(ef, dir, &new_cluster, &new_offset))
1094                         return -EIO;
1095                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
1096                                 co2o(ef, new_cluster, new_offset)) < 0)
1097                 {
1098                         exfat_error("failed to write name entry on rename");
1099                         return -EIO;
1100                 }
1101         }
1102
1103         memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
1104         tree_detach(node);
1105         tree_attach(dir, node);
1106         return 0;
1107 }
1108
1109 int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
1110 {
1111         struct exfat_node* node;
1112         struct exfat_node* existing;
1113         struct exfat_node* dir;
1114         cluster_t cluster = EXFAT_CLUSTER_BAD;
1115         off_t offset = -1;
1116         le16_t name[EXFAT_NAME_MAX + 1];
1117         int rc;
1118
1119         rc = exfat_lookup(ef, &node, old_path);
1120         if (rc != 0)
1121                 return rc;
1122
1123         rc = exfat_split(ef, &dir, &existing, name, new_path);
1124         if (rc != 0)
1125         {
1126                 exfat_put_node(ef, node);
1127                 return rc;
1128         }
1129
1130         /* check that target is not a subdirectory of the source */
1131         if (node->flags & EXFAT_ATTRIB_DIR)
1132         {
1133                 struct exfat_node* p;
1134
1135                 for (p = dir; p; p = p->parent)
1136                         if (node == p)
1137                         {
1138                                 if (existing != NULL)
1139                                         exfat_put_node(ef, existing);
1140                                 exfat_put_node(ef, dir);
1141                                 exfat_put_node(ef, node);
1142                                 return -EINVAL;
1143                         }
1144         }
1145
1146         if (existing != NULL)
1147         {
1148                 /* remove target if it's not the same node as source */
1149                 if (existing != node)
1150                 {
1151                         if (existing->flags & EXFAT_ATTRIB_DIR)
1152                         {
1153                                 if (node->flags & EXFAT_ATTRIB_DIR)
1154                                         rc = exfat_rmdir(ef, existing);
1155                                 else
1156                                         rc = -ENOTDIR;
1157                         }
1158                         else
1159                         {
1160                                 if (!(node->flags & EXFAT_ATTRIB_DIR))
1161                                         rc = exfat_unlink(ef, existing);
1162                                 else
1163                                         rc = -EISDIR;
1164                         }
1165                         exfat_put_node(ef, existing);
1166                         if (rc != 0)
1167                         {
1168                                 /* free clusters even if something went wrong; overwise they
1169                                    will be just lost */
1170                                 exfat_cleanup_node(ef, existing);
1171                                 exfat_put_node(ef, dir);
1172                                 exfat_put_node(ef, node);
1173                                 return rc;
1174                         }
1175                         rc = exfat_cleanup_node(ef, existing);
1176                         if (rc != 0)
1177                         {
1178                                 exfat_put_node(ef, dir);
1179                                 exfat_put_node(ef, node);
1180                                 return rc;
1181                         }
1182                 }
1183                 else
1184                         exfat_put_node(ef, existing);
1185         }
1186
1187         rc = find_slot(ef, dir, &cluster, &offset,
1188                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
1189         if (rc != 0)
1190         {
1191                 exfat_put_node(ef, dir);
1192                 exfat_put_node(ef, node);
1193                 return rc;
1194         }
1195         rc = rename_entry(ef, dir, node, name, cluster, offset);
1196         exfat_put_node(ef, dir);
1197         exfat_put_node(ef, node);
1198         return rc;
1199 }
1200
1201 void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
1202 {
1203         node->atime = tv[0].tv_sec;
1204         node->mtime = tv[1].tv_sec;
1205         node->flags |= EXFAT_ATTRIB_DIRTY;
1206 }
1207
1208 void exfat_update_atime(struct exfat_node* node)
1209 {
1210         node->atime = time(NULL);
1211         node->flags |= EXFAT_ATTRIB_DIRTY;
1212 }
1213
1214 void exfat_update_mtime(struct exfat_node* node)
1215 {
1216         node->mtime = time(NULL);
1217         node->flags |= EXFAT_ATTRIB_DIRTY;
1218 }
1219
1220 const char* exfat_get_label(struct exfat* ef)
1221 {
1222         return ef->label;
1223 }
1224
1225 static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
1226 {
1227         struct iterator it;
1228         int rc;
1229
1230         rc = opendir(ef, ef->root, &it);
1231         if (rc != 0)
1232                 return rc;
1233
1234         for (;;)
1235         {
1236                 if (it.offset >= ef->root->size)
1237                 {
1238                         closedir(&it);
1239                         return -ENOENT;
1240                 }
1241
1242                 if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
1243                 {
1244                         *cluster = it.cluster;
1245                         *offset = it.offset;
1246                         closedir(&it);
1247                         return 0;
1248                 }
1249
1250                 if (!fetch_next_entry(ef, ef->root, &it))
1251                 {
1252                         closedir(&it);
1253                         return -EIO;
1254                 }
1255         }
1256 }
1257
1258 int exfat_set_label(struct exfat* ef, const char* label)
1259 {
1260         le16_t label_utf16[EXFAT_ENAME_MAX + 1];
1261         int rc;
1262         cluster_t cluster;
1263         off_t offset;
1264         struct exfat_entry_label entry;
1265
1266         memset(label_utf16, 0, sizeof(label_utf16));
1267         rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
1268         if (rc != 0)
1269                 return rc;
1270
1271         rc = find_label(ef, &cluster, &offset);
1272         if (rc == -ENOENT)
1273                 rc = find_slot(ef, ef->root, &cluster, &offset, 1);
1274         if (rc != 0)
1275                 return rc;
1276
1277         entry.type = EXFAT_ENTRY_LABEL;
1278         entry.length = utf16_length(label_utf16);
1279         memcpy(entry.name, label_utf16, sizeof(entry.name));
1280         if (entry.length == 0)
1281                 entry.type ^= EXFAT_ENTRY_VALID;
1282
1283         if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
1284                         co2o(ef, cluster, offset)) < 0)
1285         {
1286                 exfat_error("failed to write label entry");
1287                 return -EIO;
1288         }
1289         strcpy(ef->label, label);
1290         return 0;
1291 }