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         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
  98
  99         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 100         {
 101                 exfat_get_name(dir, buffer, sizeof(buffer) - 1);
 102                 exfat_bug("'%s' is not a directory", buffer);
 103         }
 104         it->cluster = dir->start_cluster;
 105         it->offset = 0;
 106         it->chunk = malloc(CLUSTER_SIZE(*ef->sb));
 107         if (it->chunk == NULL)
 108         {
 109                 exfat_error("failed to allocate memory for directory cluster");
 110                 return -ENOMEM;
 111         }
 112         if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 113                         exfat_c2o(ef, it->cluster)) < 0)
 114         {
 115                 free(it->chunk);
 116                 exfat_get_name(dir, buffer, sizeof(buffer) - 1);
 117                 exfat_error("failed to read '%s' directory cluster %#x", buffer,
 118                                 it->cluster);
 119                 return -EIO;
 120         }
 121         return 0;
 122 }
 123
 124 static void closedir(struct iterator* it)
 125 {
 126         it->cluster = 0;
 127         it->offset = 0;
 128         free(it->chunk);
 129         it->chunk = NULL;
 130 }
 131
 132 static bool fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
 133                 struct iterator* it)
 134 {
 135         /* move iterator to the next entry in the directory */
 136         it->offset += sizeof(struct exfat_entry);
 137         /* fetch the next cluster if needed */
 138         if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
 139         {
 140                 /* reached the end of directory; the caller should check this
 141                    condition too */
 142                 if (it->offset >= parent->size)
 143                         return true;
 144                 it->cluster = exfat_next_cluster(ef, parent, it->cluster);
 145                 if (CLUSTER_INVALID(it->cluster))
 146                 {
 147                         exfat_error("invalid cluster 0x%x while reading directory",
 148                                         it->cluster);
 149                         return false;
 150                 }
 151                 if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
 152                                 exfat_c2o(ef, it->cluster)) < 0)
 153                 {
 154                         exfat_error("failed to read the next directory cluster %#x",
 155                                         it->cluster);
 156                         return false;
 157                 }
 158         }
 159         return true;
 160 }
 161
 162 static struct exfat_node* allocate_node(void)
 163 {
 164         struct exfat_node* node = malloc(sizeof(struct exfat_node));
 165         if (node == NULL)
 166         {
 167                 exfat_error("failed to allocate node");
 168                 return NULL;
 169         }
 170         memset(node, 0, sizeof(struct exfat_node));
 171         return node;
 172 }
 173
 174 static void init_node_meta1(struct exfat_node* node,
 175                 const struct exfat_entry_meta1* meta1)
 176 {
 177         node->flags = le16_to_cpu(meta1->attrib);
 178         node->mtime = exfat_exfat2unix(meta1->mdate, meta1->mtime,
 179                         meta1->mtime_cs);
 180         /* there is no centiseconds field for atime */
 181         node->atime = exfat_exfat2unix(meta1->adate, meta1->atime, 0);
 182 }
 183
 184 static void init_node_meta2(struct exfat_node* node,
 185                 const struct exfat_entry_meta2* meta2)
 186 {
 187         node->size = le64_to_cpu(meta2->size);
 188         node->start_cluster = le32_to_cpu(meta2->start_cluster);
 189         node->fptr_cluster = node->start_cluster;
 190         if (meta2->flags & EXFAT_FLAG_CONTIGUOUS)
 191                 node->flags |= EXFAT_ATTRIB_CONTIGUOUS;
 192 }
 193
 194 static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
 195                 const struct iterator* it)
 196 {
 197         return (const struct exfat_entry*)
 198                         (it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
 199 }
 200
 201 static bool check_node(const struct exfat_node* node, uint16_t actual_checksum,
 202                 uint16_t reference_checksum, uint64_t valid_size)
 203 {
 204         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 205         bool ret = true;
 206
 207         /*
 208            Validate checksum first. If it's invalid all other fields probably
 209            contain just garbage.
 210         */
 211         if (actual_checksum != reference_checksum)
 212         {
 213                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 214                 exfat_error("'%s' has invalid checksum (%#hx != %#hx)", buffer,
 215                                 actual_checksum, reference_checksum);
 216                 ret = false;
 217         }
 218
 219         /*
 220            exFAT does not support sparse files but allows files with uninitialized
 221            clusters. For such files valid_size means initialized data size and
 222            cannot be greater than file size. See SetFileValidData() function
 223            description in MSDN.
 224         */
 225         if (valid_size > node->size)
 226         {
 227                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 228                 exfat_error("'%s' has valid size (%"PRIu64") greater than size "
 229                                 "(%"PRIu64")", buffer, valid_size, node->size);
 230                 ret = false;
 231         }
 232
 233         return ret;
 234 }
 235
 236 static void decompress_upcase(uint16_t* output, const le16_t* source,
 237                 size_t size)
 238 {
 239         size_t si;
 240         size_t oi;
 241
 242         for (oi = 0; oi < EXFAT_UPCASE_CHARS; oi++)
 243                 output[oi] = oi;
 244
 245         for (si = 0, oi = 0; si < size && oi < EXFAT_UPCASE_CHARS; si++)
 246         {
 247                 uint16_t ch = le16_to_cpu(source[si]);
 248
 249                 if (ch == 0xffff && si + 1 < size)      /* indicates a run */
 250                         oi += le16_to_cpu(source[++si]);
 251                 else
 252                         output[oi++] = ch;
 253         }
 254 }
 255
 256 /*
 257  * Reads one entry in directory at position pointed by iterator and fills
 258  * node structure.
 259  */
 260 static int readdir(struct exfat* ef, const struct exfat_node* parent,
 261                 struct exfat_node** node, struct iterator* it)
 262 {
 263         int rc = -EIO;
 264         const struct exfat_entry* entry;
 265         const struct exfat_entry_meta1* meta1;
 266         const struct exfat_entry_meta2* meta2;
 267         const struct exfat_entry_name* file_name;
 268         const struct exfat_entry_upcase* upcase;
 269         const struct exfat_entry_bitmap* bitmap;
 270         const struct exfat_entry_label* label;
 271         uint8_t continuations = 0;
 272         le16_t* namep = NULL;
 273         uint16_t reference_checksum = 0;
 274         uint16_t actual_checksum = 0;
 275         uint64_t valid_size = 0;
 276         uint64_t upcase_size = 0;
 277         le16_t* upcase_comp = NULL;
 278
 279         *node = NULL;
 280
 281         for (;;)
 282         {
 283                 if (it->offset >= parent->size)
 284                 {
 285                         if (continuations != 0)
 286                         {
 287                                 exfat_error("expected %hhu continuations", continuations);
 288                                 goto error;
 289                         }
 290                         return -ENOENT; /* that's OK, means end of directory */
 291                 }
 292
 293                 entry = get_entry_ptr(ef, it);
 294                 switch (entry->type)
 295                 {
 296                 case EXFAT_ENTRY_FILE:
 297                         if (continuations != 0)
 298                         {
 299                                 exfat_error("expected %hhu continuations before new entry",
 300                                                 continuations);
 301                                 goto error;
 302                         }
 303                         meta1 = (const struct exfat_entry_meta1*) entry;
 304                         continuations = meta1->continuations;
 305                         /* each file entry must have at least 2 continuations:
 306                            info and name */
 307                         if (continuations < 2)
 308                         {
 309                                 exfat_error("too few continuations (%hhu)", continuations);
 310                                 goto error;
 311                         }
 312                         if (continuations > 1 +
 313                                         DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
 314                         {
 315                                 exfat_error("too many continuations (%hhu)", continuations);
 316                                 goto error;
 317                         }
 318                         reference_checksum = le16_to_cpu(meta1->checksum);
 319                         actual_checksum = exfat_start_checksum(meta1);
 320                         *node = allocate_node();
 321                         if (*node == NULL)
 322                         {
 323                                 rc = -ENOMEM;
 324                                 goto error;
 325                         }
 326                         /* new node has zero reference counter */
 327                         (*node)->entry_cluster = it->cluster;
 328                         (*node)->entry_offset = it->offset;
 329                         init_node_meta1(*node, meta1);
 330                         namep = (*node)->name;
 331                         break;
 332
 333                 case EXFAT_ENTRY_FILE_INFO:
 334                         if (continuations < 2)
 335                         {
 336                                 exfat_error("unexpected continuation (%hhu)",
 337                                                 continuations);
 338                                 goto error;
 339                         }
 340                         meta2 = (const struct exfat_entry_meta2*) entry;
 341                         if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
 342                         {
 343                                 exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
 344                                 goto error;
 345                         }
 346                         init_node_meta2(*node, meta2);
 347                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 348                         valid_size = le64_to_cpu(meta2->valid_size);
 349                         /* empty files must be marked as non-contiguous */
 350                         if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
 351                         {
 352                                 exfat_error("empty file marked as contiguous (0x%hhx)",
 353                                                 meta2->flags);
 354                                 goto error;
 355                         }
 356                         /* directories must be aligned on at cluster boundary */
 357                         if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
 358                                 (*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
 359                         {
 360                                 exfat_error("directory has invalid size %"PRIu64" bytes",
 361                                                 (*node)->size);
 362                                 goto error;
 363                         }
 364                         --continuations;
 365                         break;
 366
 367                 case EXFAT_ENTRY_FILE_NAME:
 368                         if (continuations == 0)
 369                         {
 370                                 exfat_error("unexpected continuation");
 371                                 goto error;
 372                         }
 373                         file_name = (const struct exfat_entry_name*) entry;
 374                         actual_checksum = exfat_add_checksum(entry, actual_checksum);
 375
 376                         memcpy(namep, file_name->name,
 377                                         MIN(EXFAT_ENAME_MAX,
 378                                                 ((*node)->name + EXFAT_NAME_MAX - namep)) *
 379                                         sizeof(le16_t));
 380                         namep += EXFAT_ENAME_MAX;
 381                         if (--continuations == 0)
 382                         {
 383                                 if (!check_node(*node, actual_checksum, reference_checksum,
 384                                                 valid_size))
 385                                         goto error;
 386                                 if (!fetch_next_entry(ef, parent, it))
 387                                         goto error;
 388                                 return 0; /* entry completed */
 389                         }
 390                         break;
 391
 392                 case EXFAT_ENTRY_UPCASE:
 393                         if (ef->upcase != NULL)
 394                                 break;
 395                         upcase = (const struct exfat_entry_upcase*) entry;
 396                         if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
 397                         {
 398                                 exfat_error("invalid cluster 0x%x in upcase table",
 399                                                 le32_to_cpu(upcase->start_cluster));
 400                                 goto error;
 401                         }
 402                         upcase_size = le64_to_cpu(upcase->size);
 403                         if (upcase_size == 0 ||
 404                                 upcase_size > EXFAT_UPCASE_CHARS * sizeof(uint16_t) ||
 405                                 upcase_size % sizeof(uint16_t) != 0)
 406                         {
 407                                 exfat_error("bad upcase table size (%"PRIu64" bytes)",
 408                                                 upcase_size);
 409                                 goto error;
 410                         }
 411                         upcase_comp = malloc(upcase_size);
 412                         if (upcase_comp == NULL)
 413                         {
 414                                 exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
 415                                                 upcase_size);
 416                                 rc = -ENOMEM;
 417                                 goto error;
 418                         }
 419
 420                         /* read compressed upcase table */
 421                         if (exfat_pread(ef->dev, upcase_comp, upcase_size,
 422                                         exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
 423                         {
 424                                 free(upcase_comp);
 425                                 exfat_error("failed to read upper case table "
 426                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 427                                                 upcase_size,
 428                                                 le32_to_cpu(upcase->start_cluster));
 429                                 goto error;
 430                         }
 431
 432                         /* decompress upcase table */
 433                         ef->upcase = calloc(EXFAT_UPCASE_CHARS, sizeof(uint16_t));
 434                         if (ef->upcase == NULL)
 435                         {
 436                                 free(upcase_comp);
 437                                 exfat_error("failed to allocate decompressed upcase table");
 438                                 rc = -ENOMEM;
 439                                 goto error;
 440                         }
 441                         decompress_upcase(ef->upcase, upcase_comp,
 442                                         upcase_size / sizeof(uint16_t));
 443                         free(upcase_comp);
 444                         break;
 445
 446                 case EXFAT_ENTRY_BITMAP:
 447                         bitmap = (const struct exfat_entry_bitmap*) entry;
 448                         ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
 449                         if (CLUSTER_INVALID(ef->cmap.start_cluster))
 450                         {
 451                                 exfat_error("invalid cluster 0x%x in clusters bitmap",
 452                                                 ef->cmap.start_cluster);
 453                                 goto error;
 454                         }
 455                         ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
 456                                 EXFAT_FIRST_DATA_CLUSTER;
 457                         if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
 458                         {
 459                                 exfat_error("invalid clusters bitmap size: %"PRIu64
 460                                                 " (expected at least %u)",
 461                                                 le64_to_cpu(bitmap->size),
 462                                                 DIV_ROUND_UP(ef->cmap.size, 8));
 463                                 goto error;
 464                         }
 465                         /* FIXME bitmap can be rather big, up to 512 MB */
 466                         ef->cmap.chunk_size = ef->cmap.size;
 467                         ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
 468                         if (ef->cmap.chunk == NULL)
 469                         {
 470                                 exfat_error("failed to allocate clusters bitmap chunk "
 471                                                 "(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
 472                                 rc = -ENOMEM;
 473                                 goto error;
 474                         }
 475
 476                         if (exfat_pread(ef->dev, ef->cmap.chunk,
 477                                         BMAP_SIZE(ef->cmap.chunk_size),
 478                                         exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
 479                         {
 480                                 exfat_error("failed to read clusters bitmap "
 481                                                 "(%"PRIu64" bytes starting at cluster %#x)",
 482                                                 le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
 483                                 goto error;
 484                         }
 485                         break;
 486
 487                 case EXFAT_ENTRY_LABEL:
 488                         label = (const struct exfat_entry_label*) entry;
 489                         if (label->length > EXFAT_ENAME_MAX)
 490                         {
 491                                 exfat_error("too long label (%hhu chars)", label->length);
 492                                 goto error;
 493                         }
 494                         if (utf16_to_utf8(ef->label, label->name,
 495                                                 sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
 496                                 goto error;
 497                         break;
 498
 499                 default:
 500                         if (!(entry->type & EXFAT_ENTRY_VALID))
 501                                 break; /* deleted entry, ignore it */
 502                         if (!(entry->type & EXFAT_ENTRY_OPTIONAL))
 503                         {
 504                                 exfat_error("unknown entry type %#hhx", entry->type);
 505                                 goto error;
 506                         }
 507                         /* optional entry, warn and skip */
 508                         exfat_warn("unknown entry type %#hhx", entry->type);
 509                         if (continuations == 0)
 510                         {
 511                                 exfat_error("unexpected continuation");
 512                                 goto error;
 513                         }
 514                         --continuations;
 515                         break;
 516                 }
 517
 518                 if (!fetch_next_entry(ef, parent, it))
 519                         goto error;
 520         }
 521         /* we never reach here */
 522
 523 error:
 524         free(*node);
 525         *node = NULL;
 526         return rc;
 527 }
 528
 529 int exfat_cache_directory(struct exfat* ef, struct exfat_node* dir)
 530 {
 531         struct iterator it;
 532         int rc;
 533         struct exfat_node* node;
 534         struct exfat_node* current = NULL;
 535
 536         if (dir->flags & EXFAT_ATTRIB_CACHED)
 537                 return 0; /* already cached */
 538
 539         rc = opendir(ef, dir, &it);
 540         if (rc != 0)
 541                 return rc;
 542         while ((rc = readdir(ef, dir, &node, &it)) == 0)
 543         {
 544                 node->parent = dir;
 545                 if (current != NULL)
 546                 {
 547                         current->next = node;
 548                         node->prev = current;
 549                 }
 550                 else
 551                         dir->child = node;
 552
 553                 current = node;
 554         }
 555         closedir(&it);
 556
 557         if (rc != -ENOENT)
 558         {
 559                 /* rollback */
 560                 for (current = dir->child; current; current = node)
 561                 {
 562                         node = current->next;
 563                         free(current);
 564                 }
 565                 dir->child = NULL;
 566                 return rc;
 567         }
 568
 569         dir->flags |= EXFAT_ATTRIB_CACHED;
 570         return 0;
 571 }
 572
 573 static void tree_attach(struct exfat_node* dir, struct exfat_node* node)
 574 {
 575         node->parent = dir;
 576         if (dir->child)
 577         {
 578                 dir->child->prev = node;
 579                 node->next = dir->child;
 580         }
 581         dir->child = node;
 582 }
 583
 584 static void tree_detach(struct exfat_node* node)
 585 {
 586         if (node->prev)
 587                 node->prev->next = node->next;
 588         else /* this is the first node in the list */
 589                 node->parent->child = node->next;
 590         if (node->next)
 591                 node->next->prev = node->prev;
 592         node->parent = NULL;
 593         node->prev = NULL;
 594         node->next = NULL;
 595 }
 596
 597 static void reset_cache(struct exfat* ef, struct exfat_node* node)
 598 {
 599         char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
 600
 601         while (node->child)
 602         {
 603                 struct exfat_node* p = node->child;
 604                 reset_cache(ef, p);
 605                 tree_detach(p);
 606                 free(p);
 607         }
 608         node->flags &= ~EXFAT_ATTRIB_CACHED;
 609         if (node->references != 0)
 610         {
 611                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 612                 exfat_warn("non-zero reference counter (%d) for '%s'",
 613                                 node->references, buffer);
 614         }
 615         if (node != ef->root && (node->flags & EXFAT_ATTRIB_DIRTY))
 616         {
 617                 exfat_get_name(node, buffer, sizeof(buffer) - 1);
 618                 exfat_bug("node '%s' is dirty", buffer);
 619         }
 620         while (node->references)
 621                 exfat_put_node(ef, node);
 622 }
 623
 624 void exfat_reset_cache(struct exfat* ef)
 625 {
 626         reset_cache(ef, ef->root);
 627 }
 628
 629 static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
 630                 cluster_t* cluster, off_t* offset)
 631 {
 632         *offset += sizeof(struct exfat_entry);
 633         if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
 634         {
 635                 *cluster = exfat_next_cluster(ef, parent, *cluster);
 636                 if (CLUSTER_INVALID(*cluster))
 637                 {
 638                         exfat_error("invalid cluster %#x while getting next entry",
 639                                         *cluster);
 640                         return false;
 641                 }
 642         }
 643         return true;
 644 }
 645
 646 int exfat_flush_node(struct exfat* ef, struct exfat_node* node)
 647 {
 648         cluster_t cluster;
 649         off_t offset;
 650         off_t meta1_offset, meta2_offset;
 651         struct exfat_entry_meta1 meta1;
 652         struct exfat_entry_meta2 meta2;
 653
 654         if (!(node->flags & EXFAT_ATTRIB_DIRTY))
 655                 return 0; /* no need to flush */
 656
 657         if (ef->ro)
 658                 exfat_bug("unable to flush node to read-only FS");
 659
 660         if (node->parent == NULL)
 661                 return 0; /* do not flush unlinked node */
 662
 663         cluster = node->entry_cluster;
 664         offset = node->entry_offset;
 665         meta1_offset = co2o(ef, cluster, offset);
 666         if (!next_entry(ef, node->parent, &cluster, &offset))
 667                 return -EIO;
 668         meta2_offset = co2o(ef, cluster, offset);
 669
 670         if (exfat_pread(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 671         {
 672                 exfat_error("failed to read meta1 entry on flush");
 673                 return -EIO;
 674         }
 675         if (meta1.type != EXFAT_ENTRY_FILE)
 676                 exfat_bug("invalid type of meta1: 0x%hhx", meta1.type);
 677         meta1.attrib = cpu_to_le16(node->flags);
 678         exfat_unix2exfat(node->mtime, &meta1.mdate, &meta1.mtime, &meta1.mtime_cs);
 679         exfat_unix2exfat(node->atime, &meta1.adate, &meta1.atime, NULL);
 680
 681         if (exfat_pread(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 682         {
 683                 exfat_error("failed to read meta2 entry on flush");
 684                 return -EIO;
 685         }
 686         if (meta2.type != EXFAT_ENTRY_FILE_INFO)
 687                 exfat_bug("invalid type of meta2: 0x%hhx", meta2.type);
 688         meta2.size = meta2.valid_size = cpu_to_le64(node->size);
 689         meta2.start_cluster = cpu_to_le32(node->start_cluster);
 690         meta2.flags = EXFAT_FLAG_ALWAYS1;
 691         /* empty files must not be marked as contiguous */
 692         if (node->size != 0 && IS_CONTIGUOUS(*node))
 693                 meta2.flags |= EXFAT_FLAG_CONTIGUOUS;
 694         /* name hash remains unchanged, no need to recalculate it */
 695
 696         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 697
 698         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1), meta1_offset) < 0)
 699         {
 700                 exfat_error("failed to write meta1 entry on flush");
 701                 return -EIO;
 702         }
 703         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2), meta2_offset) < 0)
 704         {
 705                 exfat_error("failed to write meta2 entry on flush");
 706                 return -EIO;
 707         }
 708
 709         node->flags &= ~EXFAT_ATTRIB_DIRTY;
 710         return exfat_flush(ef);
 711 }
 712
 713 static bool erase_entry(struct exfat* ef, struct exfat_node* node)
 714 {
 715         cluster_t cluster = node->entry_cluster;
 716         off_t offset = node->entry_offset;
 717         int name_entries = DIV_ROUND_UP(utf16_length(node->name), EXFAT_ENAME_MAX);
 718         uint8_t entry_type;
 719
 720         entry_type = EXFAT_ENTRY_FILE & ~EXFAT_ENTRY_VALID;
 721         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 722         {
 723                 exfat_error("failed to erase meta1 entry");
 724                 return false;
 725         }
 726
 727         if (!next_entry(ef, node->parent, &cluster, &offset))
 728                 return false;
 729         entry_type = EXFAT_ENTRY_FILE_INFO & ~EXFAT_ENTRY_VALID;
 730         if (exfat_pwrite(ef->dev, &entry_type, 1, co2o(ef, cluster, offset)) < 0)
 731         {
 732                 exfat_error("failed to erase meta2 entry");
 733                 return false;
 734         }
 735
 736         while (name_entries--)
 737         {
 738                 if (!next_entry(ef, node->parent, &cluster, &offset))
 739                         return false;
 740                 entry_type = EXFAT_ENTRY_FILE_NAME & ~EXFAT_ENTRY_VALID;
 741                 if (exfat_pwrite(ef->dev, &entry_type, 1,
 742                                 co2o(ef, cluster, offset)) < 0)
 743                 {
 744                         exfat_error("failed to erase name entry");
 745                         return false;
 746                 }
 747         }
 748         return true;
 749 }
 750
 751 static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
 752                 off_t deleted_offset)
 753 {
 754         const struct exfat_node* node;
 755         const struct exfat_node* last_node;
 756         uint64_t entries = 0;
 757         uint64_t new_size;
 758
 759         if (!(dir->flags & EXFAT_ATTRIB_DIR))
 760                 exfat_bug("attempted to shrink a file");
 761         if (!(dir->flags & EXFAT_ATTRIB_CACHED))
 762                 exfat_bug("attempted to shrink uncached directory");
 763
 764         for (last_node = node = dir->child; node; node = node->next)
 765         {
 766                 if (deleted_offset < node->entry_offset)
 767                 {
 768                         /* there are other entries after the removed one, no way to shrink
 769                            this directory */
 770                         return 0;
 771                 }
 772                 if (last_node->entry_offset < node->entry_offset)
 773                         last_node = node;
 774         }
 775
 776         if (last_node)
 777         {
 778                 /* offset of the last entry */
 779                 entries += last_node->entry_offset / sizeof(struct exfat_entry);
 780                 /* two subentries with meta info */
 781                 entries += 2;
 782                 /* subentries with file name */
 783                 entries += DIV_ROUND_UP(utf16_length(last_node->name),
 784                                 EXFAT_ENAME_MAX);
 785         }
 786
 787         new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
 788                                  CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
 789         if (new_size == 0) /* directory always has at least 1 cluster */
 790                 new_size = CLUSTER_SIZE(*ef->sb);
 791         if (new_size == dir->size)
 792                 return 0;
 793         return exfat_truncate(ef, dir, new_size, true);
 794 }
 795
 796 static int delete(struct exfat* ef, struct exfat_node* node)
 797 {
 798         struct exfat_node* parent = node->parent;
 799         off_t deleted_offset = node->entry_offset;
 800         int rc;
 801
 802         exfat_get_node(parent);
 803         if (!erase_entry(ef, node))
 804         {
 805                 exfat_put_node(ef, parent);
 806                 return -EIO;
 807         }
 808         exfat_update_mtime(parent);
 809         tree_detach(node);
 810         rc = shrink_directory(ef, parent, deleted_offset);
 811         node->flags |= EXFAT_ATTRIB_UNLINKED;
 812         if (rc != 0)
 813         {
 814                 exfat_flush_node(ef, parent);
 815                 exfat_put_node(ef, parent);
 816                 return rc;
 817         }
 818         rc = exfat_flush_node(ef, parent);
 819         exfat_put_node(ef, parent);
 820         return rc;
 821 }
 822
 823 int exfat_unlink(struct exfat* ef, struct exfat_node* node)
 824 {
 825         if (node->flags & EXFAT_ATTRIB_DIR)
 826                 return -EISDIR;
 827         return delete(ef, node);
 828 }
 829
 830 int exfat_rmdir(struct exfat* ef, struct exfat_node* node)
 831 {
 832         int rc;
 833
 834         if (!(node->flags & EXFAT_ATTRIB_DIR))
 835                 return -ENOTDIR;
 836         /* check that directory is empty */
 837         rc = exfat_cache_directory(ef, node);
 838         if (rc != 0)
 839                 return rc;
 840         if (node->child)
 841                 return -ENOTEMPTY;
 842         return delete(ef, node);
 843 }
 844
 845 static int grow_directory(struct exfat* ef, struct exfat_node* dir,
 846                 uint64_t asize, uint32_t difference)
 847 {
 848         return exfat_truncate(ef, dir,
 849                         DIV_ROUND_UP(asize + difference, CLUSTER_SIZE(*ef->sb))
 850                                 * CLUSTER_SIZE(*ef->sb), true);
 851 }
 852
 853 static int find_slot(struct exfat* ef, struct exfat_node* dir,
 854                 cluster_t* cluster, off_t* offset, int subentries)
 855 {
 856         struct iterator it;
 857         int rc;
 858         const struct exfat_entry* entry;
 859         int contiguous = 0;
 860
 861         rc = opendir(ef, dir, &it);
 862         if (rc != 0)
 863                 return rc;
 864         for (;;)
 865         {
 866                 if (contiguous == 0)
 867                 {
 868                         *cluster = it.cluster;
 869                         *offset = it.offset;
 870                 }
 871                 entry = get_entry_ptr(ef, &it);
 872                 if (entry->type & EXFAT_ENTRY_VALID)
 873                         contiguous = 0;
 874                 else
 875                         contiguous++;
 876                 if (contiguous == subentries)
 877                         break;  /* suitable slot is found */
 878                 if (it.offset + sizeof(struct exfat_entry) >= dir->size)
 879                 {
 880                         rc = grow_directory(ef, dir, dir->size,
 881                                         (subentries - contiguous) * sizeof(struct exfat_entry));
 882                         if (rc != 0)
 883                         {
 884                                 closedir(&it);
 885                                 return rc;
 886                         }
 887                 }
 888                 if (!fetch_next_entry(ef, dir, &it))
 889                 {
 890                         closedir(&it);
 891                         return -EIO;
 892                 }
 893         }
 894         closedir(&it);
 895         return 0;
 896 }
 897
 898 static int write_entry(struct exfat* ef, struct exfat_node* dir,
 899                 const le16_t* name, cluster_t cluster, off_t offset, uint16_t attrib)
 900 {
 901         struct exfat_node* node;
 902         struct exfat_entry_meta1 meta1;
 903         struct exfat_entry_meta2 meta2;
 904         const size_t name_length = utf16_length(name);
 905         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
 906         int i;
 907
 908         node = allocate_node();
 909         if (node == NULL)
 910                 return -ENOMEM;
 911         node->entry_cluster = cluster;
 912         node->entry_offset = offset;
 913         memcpy(node->name, name, name_length * sizeof(le16_t));
 914
 915         memset(&meta1, 0, sizeof(meta1));
 916         meta1.type = EXFAT_ENTRY_FILE;
 917         meta1.continuations = 1 + name_entries;
 918         meta1.attrib = cpu_to_le16(attrib);
 919         exfat_unix2exfat(time(NULL), &meta1.crdate, &meta1.crtime,
 920                         &meta1.crtime_cs);
 921         meta1.adate = meta1.mdate = meta1.crdate;
 922         meta1.atime = meta1.mtime = meta1.crtime;
 923         meta1.mtime_cs = meta1.crtime_cs; /* there is no atime_cs */
 924
 925         memset(&meta2, 0, sizeof(meta2));
 926         meta2.type = EXFAT_ENTRY_FILE_INFO;
 927         meta2.flags = EXFAT_FLAG_ALWAYS1;
 928         meta2.name_length = name_length;
 929         meta2.name_hash = exfat_calc_name_hash(ef, node->name);
 930         meta2.start_cluster = cpu_to_le32(EXFAT_CLUSTER_FREE);
 931
 932         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, node->name);
 933
 934         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
 935                         co2o(ef, cluster, offset)) < 0)
 936         {
 937                 exfat_error("failed to write meta1 entry");
 938                 return -EIO;
 939         }
 940         if (!next_entry(ef, dir, &cluster, &offset))
 941                 return -EIO;
 942         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
 943                         co2o(ef, cluster, offset)) < 0)
 944         {
 945                 exfat_error("failed to write meta2 entry");
 946                 return -EIO;
 947         }
 948         for (i = 0; i < name_entries; i++)
 949         {
 950                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
 951                 memcpy(name_entry.name, node->name + i * EXFAT_ENAME_MAX,
 952                                 MIN(EXFAT_ENAME_MAX, EXFAT_NAME_MAX - i * EXFAT_ENAME_MAX) *
 953                                 sizeof(le16_t));
 954                 if (!next_entry(ef, dir, &cluster, &offset))
 955                         return -EIO;
 956                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
 957                                 co2o(ef, cluster, offset)) < 0)
 958                 {
 959                         exfat_error("failed to write name entry");
 960                         return -EIO;
 961                 }
 962         }
 963
 964         init_node_meta1(node, &meta1);
 965         init_node_meta2(node, &meta2);
 966
 967         tree_attach(dir, node);
 968         exfat_update_mtime(dir);
 969         return 0;
 970 }
 971
 972 static int create(struct exfat* ef, const char* path, uint16_t attrib)
 973 {
 974         struct exfat_node* dir;
 975         struct exfat_node* existing;
 976         cluster_t cluster = EXFAT_CLUSTER_BAD;
 977         off_t offset = -1;
 978         le16_t name[EXFAT_NAME_MAX + 1];
 979         int rc;
 980
 981         rc = exfat_split(ef, &dir, &existing, name, path);
 982         if (rc != 0)
 983                 return rc;
 984         if (existing != NULL)
 985         {
 986                 exfat_put_node(ef, existing);
 987                 exfat_put_node(ef, dir);
 988                 return -EEXIST;
 989         }
 990
 991         rc = find_slot(ef, dir, &cluster, &offset,
 992                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
 993         if (rc != 0)
 994         {
 995                 exfat_put_node(ef, dir);
 996                 return rc;
 997         }
 998         rc = write_entry(ef, dir, name, cluster, offset, attrib);
 999         if (rc != 0)
1000         {
1001                 exfat_put_node(ef, dir);
1002                 return rc;
1003         }
1004         rc = exfat_flush_node(ef, dir);
1005         exfat_put_node(ef, dir);
1006         return rc;
1007 }
1008
1009 int exfat_mknod(struct exfat* ef, const char* path)
1010 {
1011         return create(ef, path, EXFAT_ATTRIB_ARCH);
1012 }
1013
1014 int exfat_mkdir(struct exfat* ef, const char* path)
1015 {
1016         int rc;
1017         struct exfat_node* node;
1018
1019         rc = create(ef, path, EXFAT_ATTRIB_DIR);
1020         if (rc != 0)
1021                 return rc;
1022         rc = exfat_lookup(ef, &node, path);
1023         if (rc != 0)
1024                 return 0;
1025         /* directories always have at least one cluster */
1026         rc = exfat_truncate(ef, node, CLUSTER_SIZE(*ef->sb), true);
1027         if (rc != 0)
1028         {
1029                 delete(ef, node);
1030                 exfat_put_node(ef, node);
1031                 return rc;
1032         }
1033         rc = exfat_flush_node(ef, node);
1034         if (rc != 0)
1035         {
1036                 delete(ef, node);
1037                 exfat_put_node(ef, node);
1038                 return rc;
1039         }
1040         exfat_put_node(ef, node);
1041         return 0;
1042 }
1043
1044 static int rename_entry(struct exfat* ef, struct exfat_node* dir,
1045                 struct exfat_node* node, const le16_t* name, cluster_t new_cluster,
1046                 off_t new_offset)
1047 {
1048         struct exfat_entry_meta1 meta1;
1049         struct exfat_entry_meta2 meta2;
1050         cluster_t old_cluster = node->entry_cluster;
1051         off_t old_offset = node->entry_offset;
1052         const size_t name_length = utf16_length(name);
1053         const int name_entries = DIV_ROUND_UP(name_length, EXFAT_ENAME_MAX);
1054         int i;
1055
1056         if (exfat_pread(ef->dev, &meta1, sizeof(meta1),
1057                         co2o(ef, old_cluster, old_offset)) < 0)
1058         {
1059                 exfat_error("failed to read meta1 entry on rename");
1060                 return -EIO;
1061         }
1062         if (!next_entry(ef, node->parent, &old_cluster, &old_offset))
1063                 return -EIO;
1064         if (exfat_pread(ef->dev, &meta2, sizeof(meta2),
1065                         co2o(ef, old_cluster, old_offset)) < 0)
1066         {
1067                 exfat_error("failed to read meta2 entry on rename");
1068                 return -EIO;
1069         }
1070         meta1.continuations = 1 + name_entries;
1071         meta2.name_hash = exfat_calc_name_hash(ef, name);
1072         meta2.name_length = name_length;
1073         meta1.checksum = exfat_calc_checksum(&meta1, &meta2, name);
1074
1075         if (!erase_entry(ef, node))
1076                 return -EIO;
1077
1078         node->entry_cluster = new_cluster;
1079         node->entry_offset = new_offset;
1080
1081         if (exfat_pwrite(ef->dev, &meta1, sizeof(meta1),
1082                         co2o(ef, new_cluster, new_offset)) < 0)
1083         {
1084                 exfat_error("failed to write meta1 entry on rename");
1085                 return -EIO;
1086         }
1087         if (!next_entry(ef, dir, &new_cluster, &new_offset))
1088                 return -EIO;
1089         if (exfat_pwrite(ef->dev, &meta2, sizeof(meta2),
1090                         co2o(ef, new_cluster, new_offset)) < 0)
1091         {
1092                 exfat_error("failed to write meta2 entry on rename");
1093                 return -EIO;
1094         }
1095
1096         for (i = 0; i < name_entries; i++)
1097         {
1098                 struct exfat_entry_name name_entry = {EXFAT_ENTRY_FILE_NAME, 0};
1099                 memcpy(name_entry.name, name + i * EXFAT_ENAME_MAX,
1100                                 EXFAT_ENAME_MAX * sizeof(le16_t));
1101                 if (!next_entry(ef, dir, &new_cluster, &new_offset))
1102                         return -EIO;
1103                 if (exfat_pwrite(ef->dev, &name_entry, sizeof(name_entry),
1104                                 co2o(ef, new_cluster, new_offset)) < 0)
1105                 {
1106                         exfat_error("failed to write name entry on rename");
1107                         return -EIO;
1108                 }
1109         }
1110
1111         memcpy(node->name, name, (EXFAT_NAME_MAX + 1) * sizeof(le16_t));
1112         tree_detach(node);
1113         tree_attach(dir, node);
1114         return 0;
1115 }
1116
1117 int exfat_rename(struct exfat* ef, const char* old_path, const char* new_path)
1118 {
1119         struct exfat_node* node;
1120         struct exfat_node* existing;
1121         struct exfat_node* dir;
1122         cluster_t cluster = EXFAT_CLUSTER_BAD;
1123         off_t offset = -1;
1124         le16_t name[EXFAT_NAME_MAX + 1];
1125         int rc;
1126
1127         rc = exfat_lookup(ef, &node, old_path);
1128         if (rc != 0)
1129                 return rc;
1130
1131         rc = exfat_split(ef, &dir, &existing, name, new_path);
1132         if (rc != 0)
1133         {
1134                 exfat_put_node(ef, node);
1135                 return rc;
1136         }
1137
1138         /* check that target is not a subdirectory of the source */
1139         if (node->flags & EXFAT_ATTRIB_DIR)
1140         {
1141                 struct exfat_node* p;
1142
1143                 for (p = dir; p; p = p->parent)
1144                         if (node == p)
1145                         {
1146                                 if (existing != NULL)
1147                                         exfat_put_node(ef, existing);
1148                                 exfat_put_node(ef, dir);
1149                                 exfat_put_node(ef, node);
1150                                 return -EINVAL;
1151                         }
1152         }
1153
1154         if (existing != NULL)
1155         {
1156                 /* remove target if it's not the same node as source */
1157                 if (existing != node)
1158                 {
1159                         if (existing->flags & EXFAT_ATTRIB_DIR)
1160                         {
1161                                 if (node->flags & EXFAT_ATTRIB_DIR)
1162                                         rc = exfat_rmdir(ef, existing);
1163                                 else
1164                                         rc = -ENOTDIR;
1165                         }
1166                         else
1167                         {
1168                                 if (!(node->flags & EXFAT_ATTRIB_DIR))
1169                                         rc = exfat_unlink(ef, existing);
1170                                 else
1171                                         rc = -EISDIR;
1172                         }
1173                         exfat_put_node(ef, existing);
1174                         if (rc != 0)
1175                         {
1176                                 /* free clusters even if something went wrong; overwise they
1177                                    will be just lost */
1178                                 exfat_cleanup_node(ef, existing);
1179                                 exfat_put_node(ef, dir);
1180                                 exfat_put_node(ef, node);
1181                                 return rc;
1182                         }
1183                         rc = exfat_cleanup_node(ef, existing);
1184                         if (rc != 0)
1185                         {
1186                                 exfat_put_node(ef, dir);
1187                                 exfat_put_node(ef, node);
1188                                 return rc;
1189                         }
1190                 }
1191                 else
1192                         exfat_put_node(ef, existing);
1193         }
1194
1195         rc = find_slot(ef, dir, &cluster, &offset,
1196                         2 + DIV_ROUND_UP(utf16_length(name), EXFAT_ENAME_MAX));
1197         if (rc != 0)
1198         {
1199                 exfat_put_node(ef, dir);
1200                 exfat_put_node(ef, node);
1201                 return rc;
1202         }
1203         rc = rename_entry(ef, dir, node, name, cluster, offset);
1204         exfat_put_node(ef, dir);
1205         exfat_put_node(ef, node);
1206         return rc;
1207 }
1208
1209 void exfat_utimes(struct exfat_node* node, const struct timespec tv[2])
1210 {
1211         node->atime = tv[0].tv_sec;
1212         node->mtime = tv[1].tv_sec;
1213         node->flags |= EXFAT_ATTRIB_DIRTY;
1214 }
1215
1216 void exfat_update_atime(struct exfat_node* node)
1217 {
1218         node->atime = time(NULL);
1219         node->flags |= EXFAT_ATTRIB_DIRTY;
1220 }
1221
1222 void exfat_update_mtime(struct exfat_node* node)
1223 {
1224         node->mtime = time(NULL);
1225         node->flags |= EXFAT_ATTRIB_DIRTY;
1226 }
1227
1228 const char* exfat_get_label(struct exfat* ef)
1229 {
1230         return ef->label;
1231 }
1232
1233 static int find_label(struct exfat* ef, cluster_t* cluster, off_t* offset)
1234 {
1235         struct iterator it;
1236         int rc;
1237
1238         rc = opendir(ef, ef->root, &it);
1239         if (rc != 0)
1240                 return rc;
1241
1242         for (;;)
1243         {
1244                 if (it.offset >= ef->root->size)
1245                 {
1246                         closedir(&it);
1247                         return -ENOENT;
1248                 }
1249
1250                 if (get_entry_ptr(ef, &it)->type == EXFAT_ENTRY_LABEL)
1251                 {
1252                         *cluster = it.cluster;
1253                         *offset = it.offset;
1254                         closedir(&it);
1255                         return 0;
1256                 }
1257
1258                 if (!fetch_next_entry(ef, ef->root, &it))
1259                 {
1260                         closedir(&it);
1261                         return -EIO;
1262                 }
1263         }
1264 }
1265
1266 int exfat_set_label(struct exfat* ef, const char* label)
1267 {
1268         le16_t label_utf16[EXFAT_ENAME_MAX + 1];
1269         int rc;
1270         cluster_t cluster;
1271         off_t offset;
1272         struct exfat_entry_label entry;
1273
1274         memset(label_utf16, 0, sizeof(label_utf16));
1275         rc = utf8_to_utf16(label_utf16, label, EXFAT_ENAME_MAX, strlen(label));
1276         if (rc != 0)
1277                 return rc;
1278
1279         rc = find_label(ef, &cluster, &offset);
1280         if (rc == -ENOENT)
1281                 rc = find_slot(ef, ef->root, &cluster, &offset, 1);
1282         if (rc != 0)
1283                 return rc;
1284
1285         entry.type = EXFAT_ENTRY_LABEL;
1286         entry.length = utf16_length(label_utf16);
1287         memcpy(entry.name, label_utf16, sizeof(entry.name));
1288         if (entry.length == 0)
1289                 entry.type ^= EXFAT_ENTRY_VALID;
1290
1291         if (exfat_pwrite(ef->dev, &entry, sizeof(struct exfat_entry_label),
1292                         co2o(ef, cluster, offset)) < 0)
1293         {
1294                 exfat_error("failed to write label entry");
1295                 return -EIO;
1296         }
1297         strcpy(ef->label, label);
1298         return 0;
1299 }