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