libexfat/node.c

   1 /*
   2         node.c (09.10.09)
   3         exFAT file system implementation library.
   4
   5         Free exFAT implementation.
   6         Copyright (C) 2010-2014  Andrew Nayenko
   7
   8         This program is free software; you can redistribute it and/or modify
   9         it under the terms of the GNU General Public License as published by
  10         the Free Software Foundation, either version 2 of the License, or
  11         (at your option) any later version.
  12
  13         This program is distributed in the hope that it will be useful,
  14         but WITHOUT ANY WARRANTY; without even the implied warranty of
  15         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16         GNU General Public License for more details.
  17
  18         You should have received a copy of the GNU General Public License along
  19         with this program; if not, write to the Free Software Foundation, Inc.,
  20         51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21 */
  22
  23 #include "exfat.h"
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <inttypes.h>
  27
  28 /* on-disk nodes iterator */
  29 struct iterator
  30 {
  31         cluster_t cluster;
  32         off_t offset;
  33         int contiguous;
  34         char* chunk;
  35 };
  36
  37 struct exfat_node* exfat_get_node(struct exfat_node* node)
  38 {
  39         /* if we switch to multi-threaded mode we will need atomic
  40            increment here and atomic decrement in exfat_put_node() */
  41         node->references++;
  42         return node;
  43 }
  44
  45 void exfat_put_node(struct exfat* ef, struct exfat_node* node)
  46 {
  47         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
  48
  49         --node->references;
  50         if (node->references < 0)
  51         {
  52                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
  53                 exfat_bug("reference counter of '%s' is below zero", buffer);
  54         }
  55         else if (node->references == 0 && node != ef->root)
  56         {
  57                 if (node->flags & EXFAT_ATTRIB_DIRTY)
  58                 {
  59                         exfat_get_name(node, buffer, sizeof(buffer) - 1);
  60                         exfat_warn("dirty node '%s' with zero references", buffer);
  61                 }
  62         }
  63 }
  64
  65 /**
  66  * This function must be called on rmdir and unlink (after the last
  67  * exfat_put_node()) to free clusters.
  68  */
  69 int exfat_cleanup_node(struct exfat* ef, struct exfat_node* node)
  70 {
  71         int rc = 0;
  72
  73         if (node->references != 0)
  74                 exfat_bug("unable to cleanup a node with %d references",
  75                                 node->references);
  76
  77         if (node->flags & EXFAT_ATTRIB_UNLINKED)
  78         {
  79                 /* free all clusters and node structure itself */
  80                 rc = exfat_truncate(ef, node, 0, true);
  81                 /* free the node even in case of error or its memory will be lost */
  82                 free(node);
  83         }
  84         return rc;
  85 }
  86
  87 /**
  88  * Cluster + offset from the beginning of the directory to absolute offset.
  89  */
  90 static off_t co2o(struct exfat* ef, cluster_t cluster, off_t offset)
  91 {
  92         return exfat_c2o(ef, cluster) + offset % CLUSTER_SIZE(*ef->sb);
  93 }
  94
  95 static int opendir(struct exfat* ef, const struct exfat_node* dir,
  96                 struct iterator* it)
  97 {
  98         if (!(dir->flags & EXFAT_ATTRIB_DIR))
  99                 exfat_bug("not a directory");
 100         it->cluster = dir->start_cluster;
 101         it->offset = 0;
 102         it->contiguous = IS_CONTIGUOUS(*dir);
 103         it->chunk = malloc(CLUSTER_SIZE(*ef->sb));
 104         if (it->chunk == NULL)
 105         {
 106                 exfat_error("out of memory");
 107                 return -ENOMEM;
 108         }
 109         if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 110                         exfat_c2o(ef, it->cluster)) < 0)
 111         {
 112                 exfat_error("failed to read directory cluster %#x", it->cluster);
 113                 return -EIO;
 114         }
 115         return 0;
 116 }
 117
 118 static void closedir(struct iterator* it)
 119 {
 120         it->cluster = 0;
 121         it->offset = 0;
 122         it->contiguous = 0;
 123         free(it->chunk);
 124         it->chunk = NULL;
 125 }
 126
 127 static bool fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 128                 struct iterator* it)
 129 {
 130         /* move iterator to the next entry in the directory */
 131         it->offset += sizeof(struct exfat_entry);
 132         /* fetch the next cluster if needed */
 133         if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
 134         {
 135                 /* reached the end of directory; the caller should check this
 136                    condition too */
 137                 if (it->offset >= parent->size)
 138                         return true;
 139                 it->cluster = exfat_next_cluster(ef, parent, it->cluster);
 140                 if (CLUSTER_INVALID(it->cluster))
 141                 {
 142                         exfat_error("invalid cluster 0x%x while reading directory",
 143                                         it->cluster);
 144                         return false;
 145                 }
 146                 if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 147                                 exfat_c2o(ef, it->cluster)) < 0)
 148                 {
 149                         exfat_error("failed to read the next directory cluster %#x",
 150                                         it->cluster);
 151                         return false;
 152                 }
 153         }
 154         return true;
 155 }
 156
 157 static struct exfat_node* allocate_node(void)
 158 {
 159         struct exfat_node* node = malloc(sizeof(struct exfat_node));
 160         if (node == NULL)
 161         {
 162                 exfat_error("failed to allocate node");
 163                 return NULL;
 164         }
 165         memset(node, 0, sizeof(struct exfat_node));
 166         return node;
 167 }
 168
 169 static void init_node_meta1(struct exfat_node* node,
 170                 const struct exfat_entry_meta1* meta1)
 171 {
 172         node->flags = le16_to_cpu(meta1->attrib);
 173         node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
 174                         meta1->mtime_cs);
 175         /* there is no centiseconds field for atime */
 176         node->atime = exfat_exfat2unix(meta1->adate, meta1->atime, 0);
 177 }
 178
 179 static void init_node_meta2(struct exfat_node* node,
 180                 const struct exfat_entry_meta2* meta2)
 181 {
 182         node->size = le64_to_cpu(meta2->size);
 183         node->start_cluster = le32_to_cpu(meta2->start_cluster);
 184         node->fptr_cluster = node->start_cluster;
 185         if (meta2->flags & EXFAT_FLAG_CONTIGUOUS)
 186                 node->flags |= EXFAT_ATTRIB_CONTIGUOUS;
 187 }
 188
 189 static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
 190                 const struct iterator* it)
 191 {
 192         return (const struct exfat_entry*)
 193                         (it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
 194 }
 195
 196 static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
 197                 uint16_t reference_checksum, uint64_t valid_size)
 198 {
 199         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 200
 201         /*
 202            Validate checksum first. If it's invalid all other fields probably
 203            contain just garbage.
 204         */
 205         if (actual_checksum != reference_checksum)
 206         {
 207                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 208                 exfat_error("'%s' has invalid checksum (%#hx != %#hx)", buffer,
 209                                 actual_checksum, reference_checksum);
 210                 return false;
 211         }
 212
 213         /*
 214            exFAT does not support sparse files but allows files with uninitialized
 215            clusters. For such files valid_size means initialized data size and
 216            cannot be greater than file size. See SetFileValidData() function
 217            description in MSDN.
 218         */
 219         if (valid_size > node->size)
 220         {
 221                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 222                 exfat_error("'%s' has valid size (%"PRIu64") greater than size "
 223                                 "(%"PRIu64")", buffer, valid_size, node->size);
 224                 return false;
 225         }
 226
 227         return true;
 228 }
 229
 230 /*
 231  * Reads one entry in directory at position pointed by iterator and fills
 232  * node structure.
 233  */
 234 static int readdir(struct exfat* ef, const struct exfat_node* parent,
 235                 struct exfat_node** node, struct iterator* it)
 236 {
 237         int rc = -EIO;
 238         const struct exfat_entry* entry;
 239         const struct exfat_entry_meta1* meta1;
 240         const struct exfat_entry_meta2* meta2;
 241         const struct exfat_entry_name* file_name;
 242         const struct exfat_entry_upcase* upcase;
 243         const struct exfat_entry_bitmap* bitmap;
 244         const struct exfat_entry_label* label;
 245         uint8_t continuations = 0;
 246         le16_t* namep = NULL;
 247         uint16_t reference_checksum = 0;
 248         uint16_t actual_checksum = 0;
 249         uint64_t valid_size = 0;
 250
 251         *node = NULL;
 252
 253         for (;;)
 254         {
 255                 if (it->offset >= parent->size)
 256                 {
 257                         if (continuations != 0)
 258                         {
 259                                 exfat_error("expected %hhu continuations", continuations);
 260                                 goto error;
 261                         }
 262                         return -ENOENT; /* that's OK, means end of directory */
 263                 }
 264
 265                 entry = get_entry_ptr(ef, it);
 266                 switch (entry->type)
 267                 {
 268                 case EXFAT_ENTRY_FILE:
 269                         if (continuations != 0)
 270                         {
 271                                 exfat_error("expected %hhu continuations before new entry",
 272                                                 continuations);
 273                                 goto error;
 274                         }
 275                         meta1 = (const struct exfat_entry_meta1*) entry;
 276                         continuations = meta1->continuations;
 277                         /* each file entry must have at least 2 continuations:
 278                            info and name */
 279                         if (continuations < 2)
 280                         {
 281                                 exfat_error("too few continuations (%hhu)", continuations);
 282                                 goto error;
 283                         }
 284                         if (continuations > 1 +
 285                                         DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
 286                         {
 287                                 exfat_error("too many continuations (%hhu)", continuations);
 288                                 goto error;
 289                         }
 290                         reference_checksum = le16_to_cpu(meta1->checksum);
 291                         actual_checksum = exfat_start_checksum(meta1);
 292                         *node = allocate_node();
 293                         if (*node == NULL)
 294                         {
 295                                 rc = -ENOMEM;
 296                                 goto error;
 297                         }
 298                         /* new node has zero reference counter */
 299                         (*node)->entry_cluster = it->cluster;
 300                         (*node)->entry_offset = it->offset;
 301                         init_node_meta1(*node, meta1);
 302                         namep = (*node)->name;
 303                         break;
 304
 305                 case EXFAT_ENTRY_FILE_INFO:
 306                         if (continuations < 2)
 307                         {
 308                                 exfat_error("unexpected continuation (%hhu)",
 309                                                 continuations);
 310                                 goto error;
 311                         }
 312                         meta2 = (const struct exfat_entry_meta2*) entry;
 313                         if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
 314                         {
 315                                 exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
 316                                 goto error;
 317                         }
 318                         init_node_meta2(*node, meta2);
 319                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 320                         valid_size = le64_to_cpu(meta2->valid_size);
 321                         /* empty files must be marked as non-contiguous */
 322                         if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
 323                         {
 324                                 exfat_error("empty file marked as contiguous (0x%hhx)",
 325                                                 meta2->flags);
 326                                 goto error;
 327                         }
 328                         /* directories must be aligned on at cluster boundary */
 329                         if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
 330                                 (*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
 331                         {
 332                                 exfat_error("directory has invalid size %"PRIu64" bytes",
 333                                                 (*node)->size);
 334                                 goto error;
 335                         }
 336                         --continuations;
 337                         break;
 338
 339                 case EXFAT_ENTRY_FILE_NAME:
 340                         if (continuations == 0)
 341                         {
 342                                 exfat_error("unexpected continuation");
 343                                 goto error;
 344                         }
 345                         file_name = (const struct exfat_entry_name*) entry;
 346                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 347
 348                         memcpy(namep, file_name->name,
 349                                         MIN(EXFAT_ENAME_MAX,
 350                                                 ((*node)->name + EXFAT_NAME_MAX - namep)) *
 351                                         sizeof(le16_t));
 352                         namep += EXFAT_ENAME_MAX;
 353                         if (--continuations == 0)
 354                         {
 355                                 if (!check_node(*node, actual_checksum, reference_checksum,
 356                                                 valid_size))
 357                                         goto error;
 358                                 if (!fetch_next_entry(ef, parent, it))
 359                                         goto error;
 360                                 return 0; /* entry completed */
 361                         }
 362                         break;
 363
 364                 case EXFAT_ENTRY_UPCASE:
 365                         if (ef->upcase != NULL)
 366                                 break;
 367                         upcase = (const struct exfat_entry_upcase*) entry;
 368                         if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
 369                         {
 370                                 exfat_error("invalid cluster 0x%x in upcase table",
 371                                                 le32_to_cpu(upcase->start_cluster));
 372                                 goto error;
 373                         }
 374                         if (le64_to_cpu(upcase->size) == 0 ||
 375                                 le64_to_cpu(upcase->size) > 0xffff * sizeof(uint16_t) ||
 376                                 le64_to_cpu(upcase->size) % sizeof(uint16_t) != 0)
 377                         {
 378                                 exfat_error("bad upcase table size (%"PRIu64" bytes)",
 379                                                 le64_to_cpu(upcase->size));
 380                                 goto error;
 381                         }
 382                         ef->upcase = malloc(le64_to_cpu(upcase->size));
 383                         if (ef->upcase == NULL)
 384                         {
 385                                 exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
 386                                                 le64_to_cpu(upcase->size));
 387                                 rc = -ENOMEM;
 388                                 goto error;
 389                         }
 390                         ef->upcase_chars = le64_to_cpu(upcase->size) / sizeof(le16_t);
 391
 392                         if (exfat_pread(ef->dev, ef->upcase, le64_to_cpu(upcase->size),
 393                                         exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 394                         {
 395                                 exfat_error("failed to read upper case table "
 396                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 397                                                 le64_to_cpu(upcase->size),
 398                                                 le32_to_cpu(upcase->start_cluster));
 399                                 goto error;
 400                         }
 401                         break;
 402
 403                 case EXFAT_ENTRY_BITMAP:
 404                         bitmap = (const struct exfat_entry_bitmap*) entry;
 405                         ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
 406                         if (CLUSTER_INVALID(ef->cmap.start_cluster))
 407                         {
 408                                 exfat_error("invalid cluster 0x%x in clusters bitmap",
 409                                                 ef->cmap.start_cluster);
 410                                 goto error;
 411                         }
 412                         ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 413                                 EXFAT_FIRST_DATA_CLUSTER;
 414                         if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 415                         {
 416                                 exfat_error("invalid clusters bitmap size: %"PRIu64
 417                                                 " (expected at least %u)",
 418                                                 le64_to_cpu(bitmap->size),
 419                                                 DIV_ROUND_UP(ef->cmap.size, 8));
 420                                 goto error;
 421                         }
 422                         /* FIXME bitmap can be rather big, up to 512 MB */
 423                         ef->cmap.chunk_size = ef->cmap.size;
 424                         ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 425                         if (ef->cmap.chunk == NULL)
 426                         {
 427                                 exfat_error("failed to allocate clusters bitmap chunk "
 428                                                 "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
 429                                 rc = -ENOMEM;
 430                                 goto error;
 431                         }
 432
 433                         if (exfat_pread(ef->dev, ef->cmap.chunk,
 434                                         BMAP_SIZE(ef->cmap.chunk_size),
 435                                         exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
 436                         {
 437                                 exfat_error("failed to read clusters bitmap "
 438                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 439                                                 le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
 440                                 goto error;
 441                         }
 442                         break;
 443
 444                 case EXFAT_ENTRY_LABEL:
 445                         label = (const struct exfat_entry_label*) entry;
 446                         if (label->length > EXFAT_ENAME_MAX)
 447                         {
 448                                 exfat_error("too long label (%hhu chars)", label->length);
 449                                 goto error;
 450                         }
 451                         if (utf16_to_utf8(ef->label, label->name,
 452                                                 sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
 453                                 goto error;
 454                         break;
 455
 456                 default:
 457                         if (entry->type & EXFAT_ENTRY_VALID)
 458                         {
 459                                 exfat_error("unknown entry type 0x%hhx", entry->type);
 460                                 goto error;
 461                         }
 462                         break;
 463                 }
 464
 465                 if (!fetch_next_entry(ef, parent, it))
 466                         goto error;
 467         }
 468         /* we never reach here */
 469
 470 error:
 471         free(*node);
 472         *node = NULL;
 473         return rc;
 474 }
 475
 476 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 477 {
 478         struct iterator it;
 479         int rc;
 480         struct exfat_node* node;
 481         struct exfat_node* current = NULL;
 482
 483         if (dir->flags & EXFAT_ATTRIB_CACHED)
 484                 return 0; /* already cached */
 485
 486         rc = opendir(ef, dir, &it);
 487         if (rc != 0)
 488                 return rc;
 489         while ((rc = readdir(ef, dir, &node, &it)) == 0)
 490         {
 491                 node->parent = dir;
 492                 if (current != NULL)
 493                 {
 494                         current->next = node;
 495                         node->prev = current;
 496                 }
 497                 else
 498                         dir->child = node;
 499
 500                 current = node;
 501         }
 502         closedir(&it);
 503
 504         if (rc != -ENOENT)
 505         {
 506                 /* rollback */
 507                 for (current = dir->child; current; current = node)
 508                 {
 509                         node = current->next;
 510                         free(current);
 511                 }
 512                 dir->child = NULL;
 513                 return rc;
 514         }
 515
 516         dir->flags |= EXFAT_ATTRIB_CACHED;
 517         return 0;
 518 }
 519
 520 static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
 521 {
 522         node->parent = dir;
 523         if (dir->child)
 524         {
 525                 dir->child->prev = node;
 526                 node->next = dir->child;
 527         }
 528         dir->child = node;
 529 }
 530
 531 static void tree_detach(struct exfat_node* node)
 532 {
 533         if (node->prev)
 534                 node->prev->next = node->next;
 535         else /* this is the first node in the list */
 536                 node->parent->child = node->next;
 537         if (node->next)
 538                 node->next->prev = node->prev;
 539         node->parent = NULL;
 540         node->prev = NULL;
 541         node->next = NULL;
 542 }
 543
 544 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 545 {
 546         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 547
 548         while (node->child)
 549         {
 550                 struct exfat_node* p = node->child;
 551                 reset_cache(ef, p);
 552                 tree_detach(p);
 553                 free(p);
 554         }
 555         node->flags &= ~EXFAT_ATTRIB_CACHED;
 556         if (node->references != 0)
 557         {
 558                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 559                 exfat_warn("non-zero reference counter (%d) for '%s'",
 560                                 node->references, buffer);
 561         }
 562         if (node != ef->root && (node->flags & EXFAT_ATTRIB_DIRTY))
 563         {
 564                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 565                 exfat_bug("node '%s' is dirty", buffer);
 566         }
 567         while (node->references)
 568                 exfat_put_node(ef, node);
 569 }
 570
 571 void exfat_reset_cache(struct exfat* ef)
 572 {
 573         reset_cache(ef, ef->root);
 574 }
 575
 576 static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 577                 cluster_t* cluster, off_t* offset)
 578 {
 579         *offset += sizeof(struct exfat_entry);
 580         if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
 581         {
 582                 *cluster = exfat_next_cluster(ef, parent, *cluster);
 583                 if (CLUSTER_INVALID(*cluster))
 584                 {
 585                         exfat_error("invalid cluster %#x while getting next entry",
 586                                         *cluster);
 587                         return false;
 588                 }
 589         }
 590         return true;
 591 }
 592
 593 int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 594 {
 595         cluster_t cluster;
 596         off_t offset;
 597         off_t meta1_offset, meta2_offset;
 598         struct exfat_entry_meta1 meta1;
 599         struct exfat_entry_meta2 meta2;
 600
 601         if (!(node->flags & EXFAT_ATTRIB_DIRTY))
 602                 return 0; /* no need to flush */
 603
 604         if (ef->ro)
 605                 exfat_bug("unable to flush node to read-only FS");
 606
 607         if (node->parent == NULL)
 608                 return 0; /* do not flush unlinked node */
 609
 610         cluster = node->entry_cluster;
 611         offset = node->entry_offset;
 612         meta1_offset = co2o(ef, cluster, offset);
 613         if (!next_entry(ef, node->parent, &cluster, &offset))
 614                 return -EIO;
 615         meta2_offset = co2o(ef, cluster, offset);
 616
 617         if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 618         {
 619                 exfat_error("failed to read meta1 entry on flush");
 620                 return -EIO;
 621         }
 622         if (meta1.type != EXFAT_ENTRY_FILE)
 623                 exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
 624         meta1.attrib = cpu_to_le16(node->flags);
 625         exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 626         exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 627
 628         if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 629         {
 630                 exfat_error("failed to read meta2 entry on flush");
 631                 return -EIO;
 632         }
 633         if (meta2.type != EXFAT_ENTRY_FILE_INFO)
 634                 exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
 635         meta2.size = meta2.valid_size = cpu_to_le64(node->size);
 636         meta2.start_cluster = cpu_to_le32(node->start_cluster);
 637         meta2.flags = EXFAT_FLAG_ALWAYS1;
 638         /* empty files must not be marked as contiguous */
 639         if (node->size != 0 && IS_CONTIGUOUS(*node))
 640                 meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 641         /* name hash remains unchanged, no need to recalculate it */
 642
 643         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 644
 645         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 646         {
 647                 exfat_error("failed to write meta1 entry on flush");
 648                 return -EIO;
 649         }
 650         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 651         {
 652                 exfat_error("failed to write meta2 entry on flush");
 653                 return -EIO;
 654         }
 655
 656         node->flags &= ~EXFAT_ATTRIB_DIRTY;
 657         return 0;
 658 }
 659
 660 static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 661 {
 662         cluster_t cluster = node->entry_cluster;
 663         off_t offset = node->entry_offset;
 664         int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
 665         uint8_t entry_type;
 666
 667         entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
 668         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 669         {
 670                 exfat_error("failed to erase meta1 entry");
 671                 return false;
 672         }
 673
 674         if (!next_entry(ef, node->parent, &cluster, &offset))
 675                 return false;
 676         entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
 677         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 678         {
 679                 exfat_error("failed to erase meta2 entry");
 680                 return false;
 681         }
 682
 683         while (name_entries--)
 684         {
 685                 if (!next_entry(ef, node->parent, &cluster, &offset))
 686                         return false;
 687                 entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
 688                 if (exfat_pwrite(ef->dev, &entry_type, 1,
 689                                 co2o(ef, cluster, offset)) < 0)
 690                 {
 691                         exfat_error("failed to erase name entry");
 692                         return false;
 693                 }
 694         }
 695         return true;
 696 }
 697
 698 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 699                 off_t deleted_offset)
 700 {
 701         const struct exfat_node* node;
 702         const struct exfat_node* last_node;
 703         uint64_t entries = 0;
 704         uint64_t new_size;
 705
 706         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 707                 exfat_bug("attempted to shrink a file");
 708         if (!(dir->flags & EXFAT_ATTRIB_CACHED))
 709                 exfat_bug("attempted to shrink uncached directory");
 710
 711         for (last_node = node = dir->child; node; node = node->next)
 712         {
 713                 if (deleted_offset < node->entry_offset)
 714                 {
 715                         /* there are other entries after the removed one, no way to shrink
 716                            this directory */
 717                         return 0;
 718                 }
 719                 if (last_node->entry_offset < node->entry_offset)
 720                         last_node = node;
 721         }
 722
 723         if (last_node)
 724         {
 725                 /* offset of the last entry */
 726                 entries += last_node->entry_offset / sizeof(struct exfat_entry);
 727                 /* two subentries with meta info */
 728                 entries += 2;
 729                 /* subentries with file name */
 730                 entries += DIV_ROUND_UP(utf16_length(last_node->name),
 731                                 EXFAT_ENAME_MAX);
 732         }
 733
 734         new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
 735                                  CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
 736         if (new_size == 0) /* directory always has at least 1 cluster */
 737                 new_size = CLUSTER_SIZE(*ef->sb);
 738         if (new_size == dir->size)
 739                 return 0;
 740         return exfat_truncate(ef, dir, new_size, true);
 741 }
 742
 743 static int delete(struct exfat* ef, struct exfat_node* node)
 744 {
 745         struct exfat_node* parent = node->parent;
 746         off_t deleted_offset = node->entry_offset;
 747         int rc;
 748
 749         exfat_get_node(parent);
 750         if (!erase_entry(ef, node))
 751         {
 752                 exfat_put_node(ef, parent);
 753                 return -EIO;
 754         }
 755         exfat_update_mtime(parent);
 756         tree_detach(node);
 757         rc = shrink_directory(ef, parent, deleted_offset);
 758         node->flags |= EXFAT_ATTRIB_UNLINKED;
 759         if (rc != 0)
 760         {
 761                 exfat_flush_node(ef, parent);
 762                 exfat_put_node(ef, parent);
 763                 return rc;
 764         }
 765         rc = exfat_flush_node(ef, parent);
 766         exfat_put_node(ef, parent);
 767         return rc;
 768 }
 769
 770 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 771 {
 772         if (node->flags & EXFAT_ATTRIB_DIR)
 773                 return -EISDIR;
 774         return delete(ef, node);
 775 }
 776
 777 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 778 {
 779         int rc;
 780
 781         if (!(node->flags & EXFAT_ATTRIB_DIR))
 782                 return -ENOTDIR;
 783         /* check that directory is empty */
 784         rc = exfat_cache_directory(ef, node);
 785         if (rc != 0)
 786                 return rc;
 787         if (node->child)
 788                 return -ENOTEMPTY;
 789         return delete(ef, node);
 790 }
 791
 792 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 793                 uint64_t asize, uint32_t difference)
 794 {
 795         return exfat_truncate(ef, dir,
 796                         DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
 797                                 * CLUSTER_SIZE(*ef->sb), true);
 798 }
 799
 800 static int find_slot(struct exfat* ef, struct exfat_node* dir,
 801                 cluster_t* cluster, off_t* offset, int subentries)
 802 {
 803         struct iterator it;
 804         int rc;
 805         const struct exfat_entry* entry;
 806         int contiguous = 0;
 807
 808         rc = opendir(ef, dir, &it);
 809         if (rc != 0)
 810                 return rc;
 811         for (;;)
 812         {
 813                 if (contiguous == 0)
 814                 {
 815                         *cluster = it.cluster;
 816                         *offset = it.offset;
 817                 }
 818                 entry = get_entry_ptr(ef, &it);
 819                 if (entry->type & EXFAT_ENTRY_VALID)
 820                         contiguous = 0;
 821                 else
 822                         contiguous++;
 823                 if (contiguous == subentries)
 824                         break;  /* suitable slot is found */
 825                 if (it.offset + sizeof(struct exfat_entry) >= dir->size)
 826                 {
 827                         rc = grow_directory(ef, dir, dir->size,
 828                                         (subentries - contiguous) * sizeof(struct exfat_entry));
 829                         if (rc != 0)
 830                         {
 831                                 closedir(&it);
 832                                 return rc;
 833                         }
 834                 }
 835                 if (!fetch_next_entry(ef, dir, &it))
 836                 {
 837                         closedir(&it);
 838                         return -EIO;
 839                 }
 840         }
 841         closedir(&it);
 842         return 0;
 843 }
 844
 845 static int write_entry(struct exfat* ef, struct exfat_node* dir,
 846                 const le16_t* name, cluster_t cluster, off_t offset, uint16_t attrib)
 847 {
 848         struct exfat_node* node;
 849         struct exfat_entry_meta1 meta1;
 850         struct exfat_entry_meta2 meta2;
 851         const size_t name_length = utf16_length(name);
 852         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 853         int i;
 854
 855         node = allocate_node();
 856         if (node == NULL)
 857                 return -ENOMEM;
 858         node->entry_cluster = cluster;
 859         node->entry_offset = offset;
 860         memcpy(node->name, name, name_length * sizeof(le16_t));
 861
 862         memset(&meta1, 0, sizeof(meta1));
 863         meta1.type = EXFAT_ENTRY_FILE;
 864         meta1.continuations = 1 + name_entries;
 865         meta1.attrib = cpu_to_le16(attrib);
 866         exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
 867                         &meta1.crtime_cs);
 868         meta1.adate = meta1.mdate = meta1.crdate;
 869         meta1.atime = meta1.mtime = meta1.crtime;
 870         meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 871
 872         memset(&meta2, 0, sizeof(meta2));
 873         meta2.type = EXFAT_ENTRY_FILE_INFO;
 874         meta2.flags = EXFAT_FLAG_ALWAYS1;
 875         meta2.name_length = name_length;
 876         meta2.name_hash = exfat_calc_name_hash(ef, node->name);
 877         meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
 878
 879         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 880
 881         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 882                         co2o(ef, cluster, offset)) < 0)
 883         {
 884                 exfat_error("failed to write meta1 entry");
 885                 return -EIO;
 886         }
 887         if (!next_entry(ef, dir, &cluster, &offset))
 888                 return -EIO;
 889         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 890                         co2o(ef, cluster, offset)) < 0)
 891         {
 892                 exfat_error("failed to write meta2 entry");
 893                 return -EIO;
 894         }
 895         for (i = 0; i < name_entries; i++)
 896         {
 897                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 898                 memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
 899                                 MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
 900                                 sizeof(le16_t));
 901                 if (!next_entry(ef, dir, &cluster, &offset))
 902                         return -EIO;
 903                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 904                                 co2o(ef, cluster, offset)) < 0)
 905                 {
 906                         exfat_error("failed to write name entry");
 907                         return -EIO;
 908                 }
 909         }
 910
 911         init_node_meta1(node, &meta1);
 912         init_node_meta2(node, &meta2);
 913
 914         tree_attach(dir, node);
 915         exfat_update_mtime(dir);
 916         return 0;
 917 }
 918
 919 static int create(struct exfat* ef, const char* path, uint16_t attrib)
 920 {
 921         struct exfat_node* dir;
 922         struct exfat_node* existing;
 923         cluster_t cluster = EXFAT_CLUSTER_BAD;
 924         off_t offset = -1;
 925         le16_t name[EXFAT_NAME_MAX + 1];
 926         int rc;
 927
 928         rc = exfat_split(ef, &dir, &existing, name, path);
 929         if (rc != 0)
 930                 return rc;
 931         if (existing != NULL)
 932         {
 933                 exfat_put_node(ef, existing);
 934                 exfat_put_node(ef, dir);
 935                 return -EEXIST;
 936         }
 937
 938         rc = find_slot(ef, dir, &cluster, &offset,
 939                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
 940         if (rc != 0)
 941         {
 942                 exfat_put_node(ef, dir);
 943                 return rc;
 944         }
 945         rc = write_entry(ef, dir, name, cluster, offset, attrib);
 946         if (rc != 0)
 947         {
 948                 exfat_put_node(ef, dir);
 949                 return rc;
 950         }
 951         rc = exfat_flush_node(ef, dir);
 952         exfat_put_node(ef, dir);
 953         return rc;
 954 }
 955
 956 int exfat_mknod(struct exfat* ef, const char* path)
 957 {
 958         return create(ef, path, EXFAT_ATTRIB_ARCH);
 959 }
 960
 961 int exfat_mkdir(struct exfat* ef, const char* path)
 962 {
 963         int rc;
 964         struct exfat_node* node;
 965
 966         rc = create(ef, path, EXFAT_ATTRIB_ARCH | EXFAT_ATTRIB_DIR);
 967         if (rc != 0)
 968                 return rc;
 969         rc = exfat_lookup(ef, &node, path);
 970         if (rc != 0)
 971                 return 0;
 972         /* directories always have at least one cluster */
 973         rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
 974         if (rc != 0)
 975         {
 976                 delete(ef, node);
 977                 exfat_put_node(ef, node);
 978                 return rc;
 979         }
 980         rc = exfat_flush_node(ef, node);
 981         if (rc != 0)
 982         {
 983                 delete(ef, node);
 984                 exfat_put_node(ef, node);
 985                 return rc;
 986         }
 987         exfat_put_node(ef, node);
 988         return 0;
 989 }
 990
 991 static int rename_entry(struct exfat* ef, struct exfat_node* dir,
 992                 struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
 993                 off_t new_offset)
 994 {
 995         struct exfat_entry_meta1 meta1;
 996         struct exfat_entry_meta2 meta2;
 997         cluster_t old_cluster = node->entry_cluster;
 998         off_t old_offset = node->entry_offset;
 999         const size_t name_length = utf16_length(name);
1000         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
1001         int i;
1002
1003         if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
1004                         co2o(ef, old_cluster, old_offset)) < 0)
1005         {
1006                 exfat_error("failed to read meta1 entry on rename");
1007                 return -EIO;
1008         }
1009         if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
1010                 return -EIO;
1011         if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
1012                         co2o(ef, old_cluster, old_offset)) < 0)
1013         {
1014                 exfat_error("failed to read meta2 entry on rename");
1015                 return -EIO;
1016         }
1017         meta1.continuations = 1 + name_entries;
1018         meta2.name_hash = exfat_calc_name_hash(ef, name);
1019         meta2.name_length = name_length;
1020         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
1021
1022         if (!erase_entry(ef, node))
1023                 return -EIO;
1024
1025         node->entry_cluster = new_cluster;
1026         node->entry_offset = new_offset;
1027
1028         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
1029                         co2o(ef, new_cluster, new_offset)) < 0)
1030         {
1031                 exfat_error("failed to write meta1 entry on rename");
1032                 return -EIO;
1033         }
1034         if (!next_entry(ef, dir, &new_cluster, &new_offset))
1035                 return -EIO;
1036         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
1037                         co2o(ef, new_cluster, new_offset)) < 0)
1038         {
1039                 exfat_error("failed to write meta2 entry on rename");
1040                 return -EIO;
1041         }
1042
1043         for (i = 0; i < name_entries; i++)
1044         {
1045                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
1046                 memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
1047                                 EXFAT_ENAME_MAX * sizeof(le16_t));
1048                 if (!next_entry(ef, dir, &new_cluster, &new_offset))
1049                         return -EIO;
1050                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
1051                                 co2o(ef, new_cluster, new_offset)) < 0)
1052                 {
1053                         exfat_error("failed to write name entry on rename");
1054                         return -EIO;
1055                 }
1056         }
1057
1058         memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
1059         tree_detach(node);
1060         tree_attach(dir, node);
1061         return 0;
1062 }
1063
1064 int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
1065 {
1066         struct exfat_node* node;
1067         struct exfat_node* existing;
1068         struct exfat_node* dir;
1069         cluster_t cluster = EXFAT_CLUSTER_BAD;
1070         off_t offset = -1;
1071         le16_t name[EXFAT_NAME_MAX + 1];
1072         int rc;
1073
1074         rc = exfat_lookup(ef, &node, old_path);
1075         if (rc != 0)
1076                 return rc;
1077
1078         rc = exfat_split(ef, &dir, &existing, name, new_path);
1079         if (rc != 0)
1080         {
1081                 exfat_put_node(ef, node);
1082                 return rc;
1083         }
1084
1085         /* check that target is not a subdirectory of the source */
1086         if (node->flags & EXFAT_ATTRIB_DIR)
1087         {
1088                 struct exfat_node* p;
1089
1090                 for (p = dir; p; p = p->parent)
1091                         if (node == p)
1092                         {
1093                                 if (existing != NULL)
1094                                         exfat_put_node(ef, existing);
1095                                 exfat_put_node(ef, dir);
1096                                 exfat_put_node(ef, node);
1097                                 return -EINVAL;
1098                         }
1099         }
1100
1101         if (existing != NULL)
1102         {
1103                 /* remove target if it's not the same node as source */
1104                 if (existing != node)
1105                 {
1106                         if (existing->flags & EXFAT_ATTRIB_DIR)
1107                         {
1108                                 if (node->flags & EXFAT_ATTRIB_DIR)
1109                                         rc = exfat_rmdir(ef, existing);
1110                                 else
1111                                         rc = -ENOTDIR;
1112                         }
1113                         else
1114                         {
1115                                 if (!(node->flags & EXFAT_ATTRIB_DIR))
1116                                         rc = exfat_unlink(ef, existing);
1117                                 else
1118                                         rc = -EISDIR;
1119                         }
1120                         exfat_put_node(ef, existing);
1121                         if (rc != 0)
1122                         {
1123                                 exfat_put_node(ef, dir);
1124                                 exfat_put_node(ef, node);
1125                                 return rc;
1126                         }
1127                 }
1128                 else
1129                         exfat_put_node(ef, existing);
1130         }
1131
1132         rc = find_slot(ef, dir, &cluster, &offset,
1133                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
1134         if (rc != 0)
1135         {
1136                 exfat_put_node(ef, dir);
1137                 exfat_put_node(ef, node);
1138                 return rc;
1139         }
1140         rc = rename_entry(ef, dir, node, name, cluster, offset);
1141         exfat_put_node(ef, dir);
1142         exfat_put_node(ef, node);
1143         return rc;
1144 }
1145
1146 void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
1147 {
1148         node->atime = tv[0].tv_sec;
1149         node->mtime = tv[1].tv_sec;
1150         node->flags |= EXFAT_ATTRIB_DIRTY;
1151 }
1152
1153 void exfat_update_atime(struct exfat_node* node)
1154 {
1155         node->atime = time(NULL);
1156         node->flags |= EXFAT_ATTRIB_DIRTY;
1157 }
1158
1159 void exfat_update_mtime(struct exfat_node* node)
1160 {
1161         node->mtime = time(NULL);
1162         node->flags |= EXFAT_ATTRIB_DIRTY;
1163 }
1164
1165 const char* exfat_get_label(struct exfat* ef)
1166 {
1167         return ef->label;
1168 }
1169
1170 static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
1171 {
1172         struct iterator it;
1173         int rc;
1174
1175         rc = opendir(ef, ef->root, &it);
1176         if (rc != 0)
1177                 return rc;
1178
1179         for (;;)
1180         {
1181                 if (it.offset >= ef->root->size)
1182                 {
1183                         closedir(&it);
1184                         return -ENOENT;
1185                 }
1186
1187                 if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
1188                 {
1189                         *cluster = it.cluster;
1190                         *offset = it.offset;
1191                         closedir(&it);
1192                         return 0;
1193                 }
1194
1195                 if (!fetch_next_entry(ef, ef->root, &it))
1196                 {
1197                         closedir(&it);
1198                         return -EIO;
1199                 }
1200         }
1201 }
1202
1203 int exfat_set_label(struct exfat* ef, const char* label)
1204 {
1205         le16_t label_utf16[EXFAT_ENAME_MAX + 1];
1206         int rc;
1207         cluster_t cluster;
1208         off_t offset;
1209         struct exfat_entry_label entry;
1210
1211         memset(label_utf16, 0, sizeof(label_utf16));
1212         rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
1213         if (rc != 0)
1214                 return rc;
1215
1216         rc = find_label(ef, &cluster, &offset);
1217         if (rc == -ENOENT)
1218                 rc = find_slot(ef, ef->root, &cluster, &offset, 1);
1219         if (rc != 0)
1220                 return rc;
1221
1222         entry.type = EXFAT_ENTRY_LABEL;
1223         entry.length = utf16_length(label_utf16);
1224         memcpy(entry.name, label_utf16, sizeof(entry.name));
1225         if (entry.length == 0)
1226                 entry.type ^= EXFAT_ENTRY_VALID;
1227
1228         if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
1229                         co2o(ef, cluster, offset)) < 0)
1230         {
1231                 exfat_error("failed to write label entry");
1232                 return -EIO;
1233         }
1234         strcpy(ef->label, label);
1235         return 0;
1236 }