wimlib.net Git - wimlib/blob - src/write.c

   1 /*
   2  * write.c
   3  *
   4  * Support for writing WIM files; write a WIM file, overwrite a WIM file, write
   5  * compressed file resources, etc.
   6  */
   7
   8 /*
   9  * Copyright (C) 2012, 2013 Eric Biggers
  10  *
  11  * This file is part of wimlib, a library for working with WIM files.
  12  *
  13  * wimlib is free software; you can redistribute it and/or modify it under the
  14  * terms of the GNU General Public License as published by the Free
  15  * Software Foundation; either version 3 of the License, or (at your option)
  16  * any later version.
  17  *
  18  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  19  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  20  * A PARTICULAR PURPOSE. See the GNU General Public License for more
  21  * details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  25  */
  26
  27 #include "config.h"
  28
  29 #if defined(HAVE_SYS_FILE_H) && defined(HAVE_FLOCK)
  30 /* On BSD, this should be included before "list.h" so that "list.h" can
  31  * overwrite the LIST_HEAD macro. */
  32 #  include <sys/file.h>
  33 #endif
  34
  35 #ifdef __WIN32__
  36 #  include "win32.h"
  37 #endif
  38
  39 #include "list.h"
  40 #include "wimlib_internal.h"
  41 #include "buffer_io.h"
  42 #include "dentry.h"
  43 #include "lookup_table.h"
  44 #include "xml.h"
  45 #include "lzx.h"
  46 #include "xpress.h"
  47
  48
  49 #ifdef ENABLE_MULTITHREADED_COMPRESSION
  50 #  include <pthread.h>
  51 #endif
  52
  53 #include <unistd.h>
  54 #include <errno.h>
  55
  56 #ifdef WITH_NTFS_3G
  57 #  include <time.h>
  58 #  include <ntfs-3g/attrib.h>
  59 #  include <ntfs-3g/inode.h>
  60 #  include <ntfs-3g/dir.h>
  61 #endif
  62
  63 #ifdef HAVE_ALLOCA_H
  64 #  include <alloca.h>
  65 #else
  66 #  include <stdlib.h>
  67 #endif
  68
  69 #include <limits.h>
  70
  71 #if defined(__WIN32__) && !defined(INVALID_HANDLE_VALUE)
  72 #  define INVALID_HANDLE_VALUE ((HANDLE)(-1))
  73 #endif
  74
  75 static int
  76 fflush_and_ftruncate(FILE *fp, off_t size)
  77 {
  78         int ret;
  79
  80         ret = fflush(fp);
  81         if (ret != 0) {
  82                 ERROR_WITH_ERRNO("Failed to flush data to output WIM file");
  83                 return WIMLIB_ERR_WRITE;
  84         }
  85         ret = ftruncate(fileno(fp), size);
  86         if (ret != 0) {
  87                 ERROR_WITH_ERRNO("Failed to truncate output WIM file to "
  88                                  "%"PRIu64" bytes", size);
  89                 return WIMLIB_ERR_WRITE;
  90         }
  91         return 0;
  92 }
  93
  94 /* Chunk table that's located at the beginning of each compressed resource in
  95  * the WIM.  (This is not the on-disk format; the on-disk format just has an
  96  * array of offsets.) */
  97 struct chunk_table {
  98         off_t file_offset;
  99         u64 num_chunks;
 100         u64 original_resource_size;
 101         u64 bytes_per_chunk_entry;
 102         u64 table_disk_size;
 103         u64 cur_offset;
 104         u64 *cur_offset_p;
 105         u64 offsets[0];
 106 };
 107
 108 /*
 109  * Allocates and initializes a chunk table, and reserves space for it in the
 110  * output file.
 111  */
 112 static int
 113 begin_wim_resource_chunk_tab(const struct wim_lookup_table_entry *lte,
 114                              FILE *out_fp,
 115                              off_t file_offset,
 116                              struct chunk_table **chunk_tab_ret)
 117 {
 118         u64 size = wim_resource_size(lte);
 119         u64 num_chunks = (size + WIM_CHUNK_SIZE - 1) / WIM_CHUNK_SIZE;
 120         size_t alloc_size = sizeof(struct chunk_table) + num_chunks * sizeof(u64);
 121         struct chunk_table *chunk_tab = CALLOC(1, alloc_size);
 122         int ret;
 123
 124         if (!chunk_tab) {
 125                 ERROR("Failed to allocate chunk table for %"PRIu64" byte "
 126                       "resource", size);
 127                 ret = WIMLIB_ERR_NOMEM;
 128                 goto out;
 129         }
 130         chunk_tab->file_offset = file_offset;
 131         chunk_tab->num_chunks = num_chunks;
 132         chunk_tab->original_resource_size = size;
 133         chunk_tab->bytes_per_chunk_entry = (size >= (1ULL << 32)) ? 8 : 4;
 134         chunk_tab->table_disk_size = chunk_tab->bytes_per_chunk_entry *
 135                                      (num_chunks - 1);
 136         chunk_tab->cur_offset = 0;
 137         chunk_tab->cur_offset_p = chunk_tab->offsets;
 138
 139         if (fwrite(chunk_tab, 1, chunk_tab->table_disk_size, out_fp) !=
 140                    chunk_tab->table_disk_size) {
 141                 ERROR_WITH_ERRNO("Failed to write chunk table in compressed "
 142                                  "file resource");
 143                 ret = WIMLIB_ERR_WRITE;
 144                 goto out;
 145         }
 146
 147         ret = 0;
 148 out:
 149         *chunk_tab_ret = chunk_tab;
 150         return ret;
 151 }
 152
 153 /*
 154  * Pointer to function to compresses a chunk of a WIM resource.
 155  *
 156  * @chunk:              Uncompressed data of the chunk.
 157  * @chunk_size:         Size of the uncompressed chunk in bytes.
 158  * @compressed_chunk:   Pointer to output buffer of size at least
 159  *                              (@chunk_size - 1) bytes.
 160  * @compressed_chunk_len_ret:   Pointer to an unsigned int into which the size
 161  *                                      of the compressed chunk will be
 162  *                                      returned.
 163  *
 164  * Returns zero if compressed succeeded, and nonzero if the chunk could not be
 165  * compressed to any smaller than @chunk_size.  This function cannot fail for
 166  * any other reasons.
 167  */
 168 typedef int (*compress_func_t)(const void *, unsigned, void *, unsigned *);
 169
 170 compress_func_t
 171 get_compress_func(int out_ctype)
 172 {
 173         if (out_ctype == WIMLIB_COMPRESSION_TYPE_LZX)
 174                 return lzx_compress;
 175         else
 176                 return xpress_compress;
 177 }
 178
 179 /*
 180  * Writes a chunk of a WIM resource to an output file.
 181  *
 182  * @chunk:        Uncompressed data of the chunk.
 183  * @chunk_size:   Size of the chunk (<= WIM_CHUNK_SIZE)
 184  * @out_fp:       FILE * to write tho chunk to.
 185  * @out_ctype:    Compression type to use when writing the chunk (ignored if no
 186  *                      chunk table provided)
 187  * @chunk_tab:    Pointer to chunk table being created.  It is updated with the
 188  *                      offset of the chunk we write.
 189  *
 190  * Returns 0 on success; nonzero on failure.
 191  */
 192 static int
 193 write_wim_resource_chunk(const u8 chunk[], unsigned chunk_size,
 194                          FILE *out_fp, compress_func_t compress,
 195                          struct chunk_table *chunk_tab)
 196 {
 197         const u8 *out_chunk;
 198         unsigned out_chunk_size;
 199         if (chunk_tab) {
 200                 u8 *compressed_chunk = alloca(chunk_size);
 201                 int ret;
 202
 203                 ret = compress(chunk, chunk_size, compressed_chunk,
 204                                &out_chunk_size);
 205                 if (ret == 0) {
 206                         out_chunk = compressed_chunk;
 207                 } else {
 208                         out_chunk = chunk;
 209                         out_chunk_size = chunk_size;
 210                 }
 211                 *chunk_tab->cur_offset_p++ = chunk_tab->cur_offset;
 212                 chunk_tab->cur_offset += out_chunk_size;
 213         } else {
 214                 out_chunk = chunk;
 215                 out_chunk_size = chunk_size;
 216         }
 217         if (fwrite(out_chunk, 1, out_chunk_size, out_fp) != out_chunk_size) {
 218                 ERROR_WITH_ERRNO("Failed to write WIM resource chunk");
 219                 return WIMLIB_ERR_WRITE;
 220         }
 221         return 0;
 222 }
 223
 224 /*
 225  * Finishes a WIM chunk table and writes it to the output file at the correct
 226  * offset.
 227  *
 228  * The final size of the full compressed resource is returned in the
 229  * @compressed_size_p.
 230  */
 231 static int
 232 finish_wim_resource_chunk_tab(struct chunk_table *chunk_tab,
 233                               FILE *out_fp, u64 *compressed_size_p)
 234 {
 235         size_t bytes_written;
 236         if (fseeko(out_fp, chunk_tab->file_offset, SEEK_SET) != 0) {
 237                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" of output "
 238                                  "WIM file", chunk_tab->file_offset);
 239                 return WIMLIB_ERR_WRITE;
 240         }
 241
 242         if (chunk_tab->bytes_per_chunk_entry == 8) {
 243                 array_cpu_to_le64(chunk_tab->offsets, chunk_tab->num_chunks);
 244         } else {
 245                 for (u64 i = 0; i < chunk_tab->num_chunks; i++)
 246                         ((u32*)chunk_tab->offsets)[i] =
 247                                 cpu_to_le32(chunk_tab->offsets[i]);
 248         }
 249         bytes_written = fwrite((u8*)chunk_tab->offsets +
 250                                         chunk_tab->bytes_per_chunk_entry,
 251                                1, chunk_tab->table_disk_size, out_fp);
 252         if (bytes_written != chunk_tab->table_disk_size) {
 253                 ERROR_WITH_ERRNO("Failed to write chunk table in compressed "
 254                                  "file resource");
 255                 return WIMLIB_ERR_WRITE;
 256         }
 257         if (fseeko(out_fp, 0, SEEK_END) != 0) {
 258                 ERROR_WITH_ERRNO("Failed to seek to end of output WIM file");
 259                 return WIMLIB_ERR_WRITE;
 260         }
 261         *compressed_size_p = chunk_tab->cur_offset + chunk_tab->table_disk_size;
 262         return 0;
 263 }
 264
 265 /* Prepare for multiple reads to a resource by caching a FILE * or NTFS
 266  * attribute pointer in the lookup table entry. */
 267 static int
 268 prepare_resource_for_read(struct wim_lookup_table_entry *lte
 269
 270                                 #ifdef WITH_NTFS_3G
 271                                 , ntfs_inode **ni_ret
 272                                 #endif
 273                         )
 274 {
 275         switch (lte->resource_location) {
 276         case RESOURCE_IN_FILE_ON_DISK:
 277                 if (!lte->file_on_disk_fp) {
 278                         lte->file_on_disk_fp = fopen(lte->file_on_disk, "rb");
 279                         if (!lte->file_on_disk_fp) {
 280                                 ERROR_WITH_ERRNO("Failed to open the file "
 281                                                  "`%s'", lte->file_on_disk);
 282                                 return WIMLIB_ERR_OPEN;
 283                         }
 284                 }
 285                 break;
 286 #ifdef WITH_NTFS_3G
 287         case RESOURCE_IN_NTFS_VOLUME:
 288                 if (!lte->attr) {
 289                         struct ntfs_location *loc = lte->ntfs_loc;
 290                         ntfs_inode *ni;
 291                         wimlib_assert(loc);
 292                         ni = ntfs_pathname_to_inode(*loc->ntfs_vol_p, NULL, loc->path);
 293                         if (!ni) {
 294                                 ERROR_WITH_ERRNO("Failed to open inode `%s' in NTFS "
 295                                                  "volume", loc->path);
 296                                 return WIMLIB_ERR_NTFS_3G;
 297                         }
 298                         lte->attr = ntfs_attr_open(ni,
 299                                                    loc->is_reparse_point ? AT_REPARSE_POINT : AT_DATA,
 300                                                    loc->stream_name,
 301                                                    loc->stream_name_nchars);
 302                         if (!lte->attr) {
 303                                 ERROR_WITH_ERRNO("Failed to open attribute of `%s' in "
 304                                                  "NTFS volume", loc->path);
 305                                 ntfs_inode_close(ni);
 306                                 return WIMLIB_ERR_NTFS_3G;
 307                         }
 308                         *ni_ret = ni;
 309                 }
 310                 break;
 311 #endif
 312 #ifdef __WIN32__
 313         case RESOURCE_WIN32:
 314                 if (lte->win32_file_on_disk_fp == INVALID_HANDLE_VALUE) {
 315                         lte->win32_file_on_disk_fp =
 316                                 win32_open_file_data_only(lte->win32_file_on_disk);
 317                         if (lte->win32_file_on_disk_fp == INVALID_HANDLE_VALUE) {
 318                                 ERROR("Win32 API: Can't open %ls", lte->win32_file_on_disk);
 319                                 win32_error_last();
 320                                 return WIMLIB_ERR_OPEN;
 321                         }
 322                 }
 323                 break;
 324 #endif
 325         default:
 326                 break;
 327         }
 328         return 0;
 329 }
 330
 331 /* Undo prepare_resource_for_read() by closing the cached FILE * or NTFS
 332  * attribute. */
 333 static void
 334 end_wim_resource_read(struct wim_lookup_table_entry *lte
 335                         #ifdef WITH_NTFS_3G
 336                                 , ntfs_inode *ni
 337                         #endif
 338                         )
 339 {
 340         if (lte->resource_location == RESOURCE_IN_FILE_ON_DISK
 341             && lte->file_on_disk_fp)
 342         {
 343                 fclose(lte->file_on_disk_fp);
 344                 lte->file_on_disk_fp = NULL;
 345         }
 346 #ifdef WITH_NTFS_3G
 347         else if (lte->resource_location == RESOURCE_IN_NTFS_VOLUME) {
 348                 if (lte->attr) {
 349                         ntfs_attr_close(lte->attr);
 350                         lte->attr = NULL;
 351                 }
 352                 if (ni)
 353                         ntfs_inode_close(ni);
 354         }
 355 #endif
 356 #ifdef __WIN32__
 357         else if (lte->resource_location == RESOURCE_WIN32
 358                  && lte->win32_file_on_disk_fp != INVALID_HANDLE_VALUE)
 359         {
 360                 win32_close_file(lte->win32_file_on_disk_fp);
 361                 lte->win32_file_on_disk_fp = INVALID_HANDLE_VALUE;
 362         }
 363 #endif
 364 }
 365
 366 static int
 367 write_uncompressed_resource_and_truncate(struct wim_lookup_table_entry *lte,
 368                                          FILE *out_fp,
 369                                          off_t file_offset,
 370                                          struct resource_entry *out_res_entry)
 371 {
 372         int ret;
 373         if (fseeko(out_fp, file_offset, SEEK_SET) != 0) {
 374                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" of "
 375                                  "output WIM file", file_offset);
 376                 return WIMLIB_ERR_WRITE;
 377         }
 378         ret = write_wim_resource(lte, out_fp, WIMLIB_COMPRESSION_TYPE_NONE,
 379                                  out_res_entry, 0);
 380         if (ret != 0)
 381                 return ret;
 382
 383         return fflush_and_ftruncate(out_fp,
 384                                     file_offset + wim_resource_size(lte));
 385 }
 386
 387 /*
 388  * Writes a WIM resource to a FILE * opened for writing.  The resource may be
 389  * written uncompressed or compressed depending on the @out_ctype parameter.
 390  *
 391  * If by chance the resource compresses to more than the original size (this may
 392  * happen with random data or files than are pre-compressed), the resource is
 393  * instead written uncompressed (and this is reflected in the @out_res_entry by
 394  * removing the WIM_RESHDR_FLAG_COMPRESSED flag).
 395  *
 396  * @lte:        The lookup table entry for the WIM resource.
 397  * @out_fp:     The FILE * to write the resource to.
 398  * @out_ctype:  The compression type of the resource to write.  Note: if this is
 399  *                      the same as the compression type of the WIM resource we
 400  *                      need to read, we simply copy the data (i.e. we do not
 401  *                      uncompress it, then compress it again).
 402  * @out_res_entry:  If non-NULL, a resource entry that is filled in with the
 403  *                  offset, original size, compressed size, and compression flag
 404  *                  of the output resource.
 405  *
 406  * Returns 0 on success; nonzero on failure.
 407  */
 408 int
 409 write_wim_resource(struct wim_lookup_table_entry *lte,
 410                    FILE *out_fp, int out_ctype,
 411                    struct resource_entry *out_res_entry,
 412                    int flags)
 413 {
 414         u64 bytes_remaining;
 415         u64 original_size;
 416         u64 old_compressed_size;
 417         u64 new_compressed_size;
 418         u64 offset;
 419         int ret;
 420         struct chunk_table *chunk_tab = NULL;
 421         bool raw;
 422         off_t file_offset;
 423         compress_func_t compress = NULL;
 424 #ifdef WITH_NTFS_3G
 425         ntfs_inode *ni = NULL;
 426 #endif
 427
 428         wimlib_assert(lte);
 429
 430         /* Original size of the resource */
 431         original_size = wim_resource_size(lte);
 432
 433         /* Compressed size of the resource (as it exists now) */
 434         old_compressed_size = wim_resource_compressed_size(lte);
 435
 436         /* Current offset in output file */
 437         file_offset = ftello(out_fp);
 438         if (file_offset == -1) {
 439                 ERROR_WITH_ERRNO("Failed to get offset in output "
 440                                  "stream");
 441                 return WIMLIB_ERR_WRITE;
 442         }
 443
 444         /* Are the compression types the same?  If so, do a raw copy (copy
 445          * without decompressing and recompressing the data). */
 446         raw = (wim_resource_compression_type(lte) == out_ctype
 447                && out_ctype != WIMLIB_COMPRESSION_TYPE_NONE
 448                && !(flags & WIMLIB_RESOURCE_FLAG_RECOMPRESS));
 449
 450         if (raw) {
 451                 flags |= WIMLIB_RESOURCE_FLAG_RAW;
 452                 bytes_remaining = old_compressed_size;
 453         } else {
 454                 flags &= ~WIMLIB_RESOURCE_FLAG_RAW;
 455                 bytes_remaining = original_size;
 456         }
 457
 458         /* Empty resource; nothing needs to be done, so just return success. */
 459         if (bytes_remaining == 0)
 460                 return 0;
 461
 462         /* Buffer for reading chunks for the resource */
 463         u8 buf[min(WIM_CHUNK_SIZE, bytes_remaining)];
 464
 465         /* If we are writing a compressed resource and not doing a raw copy, we
 466          * need to initialize the chunk table */
 467         if (out_ctype != WIMLIB_COMPRESSION_TYPE_NONE && !raw) {
 468                 ret = begin_wim_resource_chunk_tab(lte, out_fp, file_offset,
 469                                                    &chunk_tab);
 470                 if (ret != 0)
 471                         goto out;
 472         }
 473
 474         /* If the WIM resource is in an external file, open a FILE * to it so we
 475          * don't have to open a temporary one in read_wim_resource() for each
 476          * chunk. */
 477 #ifdef WITH_NTFS_3G
 478         ret = prepare_resource_for_read(lte, &ni);
 479 #else
 480         ret = prepare_resource_for_read(lte);
 481 #endif
 482         if (ret != 0)
 483                 goto out;
 484
 485         /* If we aren't doing a raw copy, we will compute the SHA1 message
 486          * digest of the resource as we read it, and verify it's the same as the
 487          * hash given in the lookup table entry once we've finished reading the
 488          * resource. */
 489         SHA_CTX ctx;
 490         if (!raw) {
 491                 sha1_init(&ctx);
 492                 compress = get_compress_func(out_ctype);
 493         }
 494         offset = 0;
 495
 496         /* While there are still bytes remaining in the WIM resource, read a
 497          * chunk of the resource, update SHA1, then write that chunk using the
 498          * desired compression type. */
 499         do {
 500                 u64 to_read = min(bytes_remaining, WIM_CHUNK_SIZE);
 501                 ret = read_wim_resource(lte, buf, to_read, offset, flags);
 502                 if (ret != 0)
 503                         goto out_fclose;
 504                 if (!raw)
 505                         sha1_update(&ctx, buf, to_read);
 506                 ret = write_wim_resource_chunk(buf, to_read, out_fp,
 507                                                compress, chunk_tab);
 508                 if (ret != 0)
 509                         goto out_fclose;
 510                 bytes_remaining -= to_read;
 511                 offset += to_read;
 512         } while (bytes_remaining);
 513
 514         /* Raw copy:  The new compressed size is the same as the old compressed
 515          * size
 516          *
 517          * Using WIMLIB_COMPRESSION_TYPE_NONE:  The new compressed size is the
 518          * original size
 519          *
 520          * Using a different compression type:  Call
 521          * finish_wim_resource_chunk_tab() and it will provide the new
 522          * compressed size.
 523          */
 524         if (raw) {
 525                 new_compressed_size = old_compressed_size;
 526         } else {
 527                 if (out_ctype == WIMLIB_COMPRESSION_TYPE_NONE)
 528                         new_compressed_size = original_size;
 529                 else {
 530                         ret = finish_wim_resource_chunk_tab(chunk_tab, out_fp,
 531                                                             &new_compressed_size);
 532                         if (ret != 0)
 533                                 goto out_fclose;
 534                 }
 535         }
 536
 537         /* Verify SHA1 message digest of the resource, unless we are doing a raw
 538          * write (in which case we never even saw the uncompressed data).  Or,
 539          * if the hash we had before is all 0's, just re-set it to be the new
 540          * hash. */
 541         if (!raw) {
 542                 u8 md[SHA1_HASH_SIZE];
 543                 sha1_final(md, &ctx);
 544                 if (is_zero_hash(lte->hash)) {
 545                         copy_hash(lte->hash, md);
 546                 } else if (!hashes_equal(md, lte->hash)) {
 547                         ERROR("WIM resource has incorrect hash!");
 548                         if (lte->resource_location == RESOURCE_IN_FILE_ON_DISK) {
 549                                 ERROR("We were reading it from `%s'; maybe it changed "
 550                                       "while we were reading it.",
 551                                       lte->file_on_disk);
 552                         }
 553                         ret = WIMLIB_ERR_INVALID_RESOURCE_HASH;
 554                         goto out_fclose;
 555                 }
 556         }
 557
 558         if (!raw && new_compressed_size >= original_size &&
 559             out_ctype != WIMLIB_COMPRESSION_TYPE_NONE)
 560         {
 561                 /* Oops!  We compressed the resource to larger than the original
 562                  * size.  Write the resource uncompressed instead. */
 563                 ret = write_uncompressed_resource_and_truncate(lte,
 564                                                                out_fp,
 565                                                                file_offset,
 566                                                                out_res_entry);
 567                 if (ret != 0)
 568                         goto out_fclose;
 569         } else {
 570                 if (out_res_entry) {
 571                         out_res_entry->size          = new_compressed_size;
 572                         out_res_entry->original_size = original_size;
 573                         out_res_entry->offset        = file_offset;
 574                         out_res_entry->flags         = lte->resource_entry.flags
 575                                                         & ~WIM_RESHDR_FLAG_COMPRESSED;
 576                         if (out_ctype != WIMLIB_COMPRESSION_TYPE_NONE)
 577                                 out_res_entry->flags |= WIM_RESHDR_FLAG_COMPRESSED;
 578                 }
 579         }
 580         ret = 0;
 581 out_fclose:
 582 #ifdef WITH_NTFS_3G
 583         end_wim_resource_read(lte, ni);
 584 #else
 585         end_wim_resource_read(lte);
 586 #endif
 587 out:
 588         FREE(chunk_tab);
 589         return ret;
 590 }
 591
 592 #ifdef ENABLE_MULTITHREADED_COMPRESSION
 593
 594 /* Blocking shared queue (solves the producer-consumer problem) */
 595 struct shared_queue {
 596         unsigned size;
 597         unsigned front;
 598         unsigned back;
 599         unsigned filled_slots;
 600         void **array;
 601         pthread_mutex_t lock;
 602         pthread_cond_t msg_avail_cond;
 603         pthread_cond_t space_avail_cond;
 604 };
 605
 606 static int
 607 shared_queue_init(struct shared_queue *q, unsigned size)
 608 {
 609         wimlib_assert(size != 0);
 610         q->array = CALLOC(sizeof(q->array[0]), size);
 611         if (!q->array)
 612                 return WIMLIB_ERR_NOMEM;
 613         q->filled_slots = 0;
 614         q->front = 0;
 615         q->back = size - 1;
 616         q->size = size;
 617         pthread_mutex_init(&q->lock, NULL);
 618         pthread_cond_init(&q->msg_avail_cond, NULL);
 619         pthread_cond_init(&q->space_avail_cond, NULL);
 620         return 0;
 621 }
 622
 623 static void
 624 shared_queue_destroy(struct shared_queue *q)
 625 {
 626         FREE(q->array);
 627         pthread_mutex_destroy(&q->lock);
 628         pthread_cond_destroy(&q->msg_avail_cond);
 629         pthread_cond_destroy(&q->space_avail_cond);
 630 }
 631
 632 static void
 633 shared_queue_put(struct shared_queue *q, void *obj)
 634 {
 635         pthread_mutex_lock(&q->lock);
 636         while (q->filled_slots == q->size)
 637                 pthread_cond_wait(&q->space_avail_cond, &q->lock);
 638
 639         q->back = (q->back + 1) % q->size;
 640         q->array[q->back] = obj;
 641         q->filled_slots++;
 642
 643         pthread_cond_broadcast(&q->msg_avail_cond);
 644         pthread_mutex_unlock(&q->lock);
 645 }
 646
 647 static void *
 648 shared_queue_get(struct shared_queue *q)
 649 {
 650         void *obj;
 651
 652         pthread_mutex_lock(&q->lock);
 653         while (q->filled_slots == 0)
 654                 pthread_cond_wait(&q->msg_avail_cond, &q->lock);
 655
 656         obj = q->array[q->front];
 657         q->array[q->front] = NULL;
 658         q->front = (q->front + 1) % q->size;
 659         q->filled_slots--;
 660
 661         pthread_cond_broadcast(&q->space_avail_cond);
 662         pthread_mutex_unlock(&q->lock);
 663         return obj;
 664 }
 665
 666 struct compressor_thread_params {
 667         struct shared_queue *res_to_compress_queue;
 668         struct shared_queue *compressed_res_queue;
 669         compress_func_t compress;
 670 };
 671
 672 #define MAX_CHUNKS_PER_MSG 2
 673
 674 struct message {
 675         struct wim_lookup_table_entry *lte;
 676         u8 *uncompressed_chunks[MAX_CHUNKS_PER_MSG];
 677         u8 *out_compressed_chunks[MAX_CHUNKS_PER_MSG];
 678         u8 *compressed_chunks[MAX_CHUNKS_PER_MSG];
 679         unsigned uncompressed_chunk_sizes[MAX_CHUNKS_PER_MSG];
 680         unsigned compressed_chunk_sizes[MAX_CHUNKS_PER_MSG];
 681         unsigned num_chunks;
 682         struct list_head list;
 683         bool complete;
 684         u64 begin_chunk;
 685 };
 686
 687 static void
 688 compress_chunks(struct message *msg, compress_func_t compress)
 689 {
 690         for (unsigned i = 0; i < msg->num_chunks; i++) {
 691                 DEBUG2("compress chunk %u of %u", i, msg->num_chunks);
 692                 int ret = compress(msg->uncompressed_chunks[i],
 693                                    msg->uncompressed_chunk_sizes[i],
 694                                    msg->compressed_chunks[i],
 695                                    &msg->compressed_chunk_sizes[i]);
 696                 if (ret == 0) {
 697                         msg->out_compressed_chunks[i] = msg->compressed_chunks[i];
 698                 } else {
 699                         msg->out_compressed_chunks[i] = msg->uncompressed_chunks[i];
 700                         msg->compressed_chunk_sizes[i] = msg->uncompressed_chunk_sizes[i];
 701                 }
 702         }
 703 }
 704
 705 /* Compressor thread routine.  This is a lot simpler than the main thread
 706  * routine: just repeatedly get a group of chunks from the
 707  * res_to_compress_queue, compress them, and put them in the
 708  * compressed_res_queue.  A NULL pointer indicates that the thread should stop.
 709  * */
 710 static void *
 711 compressor_thread_proc(void *arg)
 712 {
 713         struct compressor_thread_params *params = arg;
 714         struct shared_queue *res_to_compress_queue = params->res_to_compress_queue;
 715         struct shared_queue *compressed_res_queue = params->compressed_res_queue;
 716         compress_func_t compress = params->compress;
 717         struct message *msg;
 718
 719         DEBUG("Compressor thread ready");
 720         while ((msg = shared_queue_get(res_to_compress_queue)) != NULL) {
 721                 compress_chunks(msg, compress);
 722                 shared_queue_put(compressed_res_queue, msg);
 723         }
 724         DEBUG("Compressor thread terminating");
 725         return NULL;
 726 }
 727 #endif /* ENABLE_MULTITHREADED_COMPRESSION */
 728
 729 static int
 730 do_write_stream_list(struct list_head *my_resources,
 731                      FILE *out_fp,
 732                      int out_ctype,
 733                      wimlib_progress_func_t progress_func,
 734                      union wimlib_progress_info *progress,
 735                      int write_resource_flags)
 736 {
 737         int ret;
 738         struct wim_lookup_table_entry *lte, *tmp;
 739
 740         list_for_each_entry_safe(lte, tmp, my_resources, staging_list) {
 741                 ret = write_wim_resource(lte,
 742                                          out_fp,
 743                                          out_ctype,
 744                                          &lte->output_resource_entry,
 745                                          write_resource_flags);
 746                 if (ret != 0)
 747                         return ret;
 748                 list_del(&lte->staging_list);
 749                 progress->write_streams.completed_bytes +=
 750                         wim_resource_size(lte);
 751                 progress->write_streams.completed_streams++;
 752                 if (progress_func) {
 753                         progress_func(WIMLIB_PROGRESS_MSG_WRITE_STREAMS,
 754                                       progress);
 755                 }
 756         }
 757         return 0;
 758 }
 759
 760 static int
 761 write_stream_list_serial(struct list_head *stream_list,
 762                          FILE *out_fp,
 763                          int out_ctype,
 764                          int write_flags,
 765                          wimlib_progress_func_t progress_func,
 766                          union wimlib_progress_info *progress)
 767 {
 768         int write_resource_flags;
 769
 770         if (write_flags & WIMLIB_WRITE_FLAG_RECOMPRESS)
 771                 write_resource_flags = WIMLIB_RESOURCE_FLAG_RECOMPRESS;
 772         else
 773                 write_resource_flags = 0;
 774         progress->write_streams.num_threads = 1;
 775         if (progress_func)
 776                 progress_func(WIMLIB_PROGRESS_MSG_WRITE_STREAMS, progress);
 777         return do_write_stream_list(stream_list, out_fp,
 778                                     out_ctype, progress_func,
 779                                     progress, write_resource_flags);
 780 }
 781
 782 #ifdef ENABLE_MULTITHREADED_COMPRESSION
 783 static int
 784 write_wim_chunks(struct message *msg, FILE *out_fp,
 785                  struct chunk_table *chunk_tab)
 786 {
 787         for (unsigned i = 0; i < msg->num_chunks; i++) {
 788                 unsigned chunk_csize = msg->compressed_chunk_sizes[i];
 789
 790                 DEBUG2("Write wim chunk %u of %u (csize = %u)",
 791                       i, msg->num_chunks, chunk_csize);
 792
 793                 if (fwrite(msg->out_compressed_chunks[i], 1, chunk_csize, out_fp)
 794                     != chunk_csize)
 795                 {
 796                         ERROR_WITH_ERRNO("Failed to write WIM chunk");
 797                         return WIMLIB_ERR_WRITE;
 798                 }
 799
 800                 *chunk_tab->cur_offset_p++ = chunk_tab->cur_offset;
 801                 chunk_tab->cur_offset += chunk_csize;
 802         }
 803         return 0;
 804 }
 805
 806 /*
 807  * This function is executed by the main thread when the resources are being
 808  * compressed in parallel.  The main thread is in change of all reading of the
 809  * uncompressed data and writing of the compressed data.  The compressor threads
 810  * *only* do compression from/to in-memory buffers.
 811  *
 812  * Each unit of work given to a compressor thread is up to MAX_CHUNKS_PER_MSG
 813  * chunks of compressed data to compress, represented in a `struct message'.
 814  * Each message is passed from the main thread to a worker thread through the
 815  * res_to_compress_queue, and it is passed back through the
 816  * compressed_res_queue.
 817  */
 818 static int
 819 main_writer_thread_proc(struct list_head *stream_list,
 820                         FILE *out_fp,
 821                         int out_ctype,
 822                         struct shared_queue *res_to_compress_queue,
 823                         struct shared_queue *compressed_res_queue,
 824                         size_t num_messages,
 825                         int write_flags,
 826                         wimlib_progress_func_t progress_func,
 827                         union wimlib_progress_info *progress)
 828 {
 829         int ret;
 830         struct chunk_table *cur_chunk_tab = NULL;
 831         struct message *msgs = CALLOC(num_messages, sizeof(struct message));
 832         struct wim_lookup_table_entry *next_lte = NULL;
 833
 834         // Initially, all the messages are available to use.
 835         LIST_HEAD(available_msgs);
 836
 837         if (!msgs) {
 838                 ret = WIMLIB_ERR_NOMEM;
 839                 goto out;
 840         }
 841
 842         for (size_t i = 0; i < num_messages; i++)
 843                 list_add(&msgs[i].list, &available_msgs);
 844
 845         // outstanding_resources is the list of resources that currently have
 846         // had chunks sent off for compression.
 847         //
 848         // The first stream in outstanding_resources is the stream that is
 849         // currently being written (cur_lte).
 850         //
 851         // The last stream in outstanding_resources is the stream that is
 852         // currently being read and chunks fed to the compressor threads
 853         // (next_lte).
 854         //
 855         // Depending on the number of threads and the sizes of the resource,
 856         // the outstanding streams list may contain streams between cur_lte and
 857         // next_lte that have all their chunks compressed or being compressed,
 858         // but haven't been written yet.
 859         //
 860         LIST_HEAD(outstanding_resources);
 861         struct list_head *next_resource = stream_list->next;
 862         u64 next_chunk = 0;
 863         u64 next_num_chunks = 0;
 864
 865         // As in write_wim_resource(), each resource we read is checksummed.
 866         SHA_CTX next_sha_ctx;
 867         u8 next_hash[SHA1_HASH_SIZE];
 868
 869         // Resources that don't need any chunks compressed are added to this
 870         // list and written directly by the main thread.
 871         LIST_HEAD(my_resources);
 872
 873         struct wim_lookup_table_entry *cur_lte = NULL;
 874         struct message *msg;
 875
 876 #ifdef WITH_NTFS_3G
 877         ntfs_inode *ni = NULL;
 878 #endif
 879
 880         DEBUG("Initializing buffers for uncompressed "
 881               "and compressed data (%zu bytes needed)",
 882               num_messages * MAX_CHUNKS_PER_MSG * WIM_CHUNK_SIZE * 2);
 883
 884         // Pre-allocate all the buffers that will be needed to do the chunk
 885         // compression.
 886         for (size_t i = 0; i < num_messages; i++) {
 887                 for (size_t j = 0; j < MAX_CHUNKS_PER_MSG; j++) {
 888                         msgs[i].compressed_chunks[j] = MALLOC(WIM_CHUNK_SIZE);
 889
 890                         // The extra 8 bytes is because longest_match() in
 891                         // lz77.c may read a little bit off the end of the
 892                         // uncompressed data.  It doesn't need to be
 893                         // initialized--- we really just need to avoid accessing
 894                         // an unmapped page.
 895                         msgs[i].uncompressed_chunks[j] = MALLOC(WIM_CHUNK_SIZE + 8);
 896                         if (msgs[i].compressed_chunks[j] == NULL ||
 897                             msgs[i].uncompressed_chunks[j] == NULL)
 898                         {
 899                                 ret = WIMLIB_ERR_NOMEM;
 900                                 goto out;
 901                         }
 902                 }
 903         }
 904
 905         // This loop is executed until all resources have been written, except
 906         // possibly a few that have been added to the @my_resources list for
 907         // writing later.
 908         while (1) {
 909                 // Send chunks to the compressor threads until either (a) there
 910                 // are no more messages available since they were all sent off,
 911                 // or (b) there are no more resources that need to be
 912                 // compressed.
 913                 while (!list_empty(&available_msgs)) {
 914                         if (next_chunk == next_num_chunks) {
 915                                 // If next_chunk == next_num_chunks, there are
 916                                 // no more chunks to write in the current
 917                                 // stream.  So, check the SHA1 message digest of
 918                                 // the stream that was just finished (unless
 919                                 // next_lte == NULL, which is the case the very
 920                                 // first time this loop is entered, and also
 921                                 // near the very end of the compression when
 922                                 // there are no more streams.)  Then, advance to
 923                                 // the next stream (if there is one).
 924                                 if (next_lte != NULL) {
 925                                 #ifdef WITH_NTFS_3G
 926                                         end_wim_resource_read(next_lte, ni);
 927                                         ni = NULL;
 928                                 #else
 929                                         end_wim_resource_read(next_lte);
 930                                 #endif
 931                                         DEBUG2("Finalize SHA1 md (next_num_chunks=%zu)",
 932                                                next_num_chunks);
 933                                         sha1_final(next_hash, &next_sha_ctx);
 934                                         if (!hashes_equal(next_lte->hash, next_hash)) {
 935                                                 ERROR("WIM resource has incorrect hash!");
 936                                                 if (next_lte->resource_location ==
 937                                                     RESOURCE_IN_FILE_ON_DISK)
 938                                                 {
 939                                                         ERROR("We were reading it from `%s'; "
 940                                                               "maybe it changed while we were "
 941                                                               "reading it.",
 942                                                               next_lte->file_on_disk);
 943                                                 }
 944                                                 ret = WIMLIB_ERR_INVALID_RESOURCE_HASH;
 945                                                 goto out;
 946                                         }
 947                                 }
 948
 949                                 // Advance to the next resource.
 950                                 //
 951                                 // If the next resource needs no compression, just write
 952                                 // it with this thread (not now though--- we could be in
 953                                 // the middle of writing another resource.)  Keep doing
 954                                 // this until we either get to the end of the resources
 955                                 // list, or we get to a resource that needs compression.
 956                                 while (1) {
 957                                         if (next_resource == stream_list) {
 958                                                 // No more resources to send for
 959                                                 // compression
 960                                                 next_lte = NULL;
 961                                                 break;
 962                                         }
 963                                         next_lte = container_of(next_resource,
 964                                                                 struct wim_lookup_table_entry,
 965                                                                 staging_list);
 966                                         next_resource = next_resource->next;
 967                                         if ((!(write_flags & WIMLIB_WRITE_FLAG_RECOMPRESS)
 968                                                && wim_resource_compression_type(next_lte) == out_ctype)
 969                                             || wim_resource_size(next_lte) == 0)
 970                                         {
 971                                                 list_add_tail(&next_lte->staging_list,
 972                                                               &my_resources);
 973                                         } else {
 974                                                 list_add_tail(&next_lte->staging_list,
 975                                                               &outstanding_resources);
 976                                                 next_chunk = 0;
 977                                                 next_num_chunks = wim_resource_chunks(next_lte);
 978                                                 sha1_init(&next_sha_ctx);
 979                                                 INIT_LIST_HEAD(&next_lte->msg_list);
 980                                         #ifdef WITH_NTFS_3G
 981                                                 ret = prepare_resource_for_read(next_lte, &ni);
 982                                         #else
 983                                                 ret = prepare_resource_for_read(next_lte);
 984                                         #endif
 985
 986                                                 if (ret != 0)
 987                                                         goto out;
 988                                                 if (cur_lte == NULL) {
 989                                                         // Set cur_lte for the
 990                                                         // first time
 991                                                         cur_lte = next_lte;
 992                                                 }
 993                                                 break;
 994                                         }
 995                                 }
 996                         }
 997
 998                         if (next_lte == NULL) {
 999                                 // No more resources to send for compression
1000                                 break;
1001                         }
1002
1003                         // Get a message from the available messages
1004                         // list
1005                         msg = container_of(available_msgs.next,
1006                                            struct message,
1007                                            list);
1008
1009                         // ... and delete it from the available messages
1010                         // list
1011                         list_del(&msg->list);
1012
1013                         // Initialize the message with the chunks to
1014                         // compress.
1015                         msg->num_chunks = min(next_num_chunks - next_chunk,
1016                                               MAX_CHUNKS_PER_MSG);
1017                         msg->lte = next_lte;
1018                         msg->complete = false;
1019                         msg->begin_chunk = next_chunk;
1020
1021                         unsigned size = WIM_CHUNK_SIZE;
1022                         for (unsigned i = 0; i < msg->num_chunks; i++) {
1023
1024                                 // Read chunk @next_chunk of the stream into the
1025                                 // message so that a compressor thread can
1026                                 // compress it.
1027
1028                                 if (next_chunk == next_num_chunks - 1) {
1029                                         size = MODULO_NONZERO(wim_resource_size(next_lte),
1030                                                               WIM_CHUNK_SIZE);
1031                                 }
1032
1033                                 DEBUG2("Read resource (size=%u, offset=%zu)",
1034                                       size, next_chunk * WIM_CHUNK_SIZE);
1035
1036                                 msg->uncompressed_chunk_sizes[i] = size;
1037
1038                                 ret = read_wim_resource(next_lte,
1039                                                         msg->uncompressed_chunks[i],
1040                                                         size,
1041                                                         next_chunk * WIM_CHUNK_SIZE,
1042                                                         0);
1043                                 if (ret != 0)
1044                                         goto out;
1045                                 sha1_update(&next_sha_ctx,
1046                                             msg->uncompressed_chunks[i], size);
1047                                 next_chunk++;
1048                         }
1049
1050                         // Send the compression request
1051                         list_add_tail(&msg->list, &next_lte->msg_list);
1052                         shared_queue_put(res_to_compress_queue, msg);
1053                         DEBUG2("Compression request sent");
1054                 }
1055
1056                 // If there are no outstanding resources, there are no more
1057                 // resources that need to be written.
1058                 if (list_empty(&outstanding_resources)) {
1059                         ret = 0;
1060                         goto out;
1061                 }
1062
1063                 // Get the next message from the queue and process it.
1064                 // The message will contain 1 or more data chunks that have been
1065                 // compressed.
1066                 msg = shared_queue_get(compressed_res_queue);
1067                 msg->complete = true;
1068
1069                 // Is this the next chunk in the current resource?  If it's not
1070                 // (i.e., an earlier chunk in a same or different resource
1071                 // hasn't been compressed yet), do nothing, and keep this
1072                 // message around until all earlier chunks are received.
1073                 //
1074                 // Otherwise, write all the chunks we can.
1075                 while (cur_lte != NULL &&
1076                        !list_empty(&cur_lte->msg_list) &&
1077                        (msg = container_of(cur_lte->msg_list.next,
1078                                            struct message,
1079                                            list))->complete)
1080                 {
1081                         DEBUG2("Complete msg (begin_chunk=%"PRIu64")", msg->begin_chunk);
1082                         if (msg->begin_chunk == 0) {
1083                                 DEBUG2("Begin chunk tab");
1084
1085                                 // This is the first set of chunks.  Leave space
1086                                 // for the chunk table in the output file.
1087                                 off_t cur_offset = ftello(out_fp);
1088                                 if (cur_offset == -1) {
1089                                         ret = WIMLIB_ERR_WRITE;
1090                                         goto out;
1091                                 }
1092                                 ret = begin_wim_resource_chunk_tab(cur_lte,
1093                                                                    out_fp,
1094                                                                    cur_offset,
1095                                                                    &cur_chunk_tab);
1096                                 if (ret != 0)
1097                                         goto out;
1098                         }
1099
1100                         // Write the compressed chunks from the message.
1101                         ret = write_wim_chunks(msg, out_fp, cur_chunk_tab);
1102                         if (ret != 0)
1103                                 goto out;
1104
1105                         list_del(&msg->list);
1106
1107                         // This message is available to use for different chunks
1108                         // now.
1109                         list_add(&msg->list, &available_msgs);
1110
1111                         // Was this the last chunk of the stream?  If so, finish
1112                         // it.
1113                         if (list_empty(&cur_lte->msg_list) &&
1114                             msg->begin_chunk + msg->num_chunks == cur_chunk_tab->num_chunks)
1115                         {
1116                                 DEBUG2("Finish wim chunk tab");
1117                                 u64 res_csize;
1118                                 ret = finish_wim_resource_chunk_tab(cur_chunk_tab,
1119                                                                     out_fp,
1120                                                                     &res_csize);
1121                                 if (ret != 0)
1122                                         goto out;
1123
1124                                 if (res_csize >= wim_resource_size(cur_lte)) {
1125                                         /* Oops!  We compressed the resource to
1126                                          * larger than the original size.  Write
1127                                          * the resource uncompressed instead. */
1128                                         ret = write_uncompressed_resource_and_truncate(
1129                                                          cur_lte,
1130                                                          out_fp,
1131                                                          cur_chunk_tab->file_offset,
1132                                                          &cur_lte->output_resource_entry);
1133                                         if (ret != 0)
1134                                                 goto out;
1135                                 } else {
1136                                         cur_lte->output_resource_entry.size =
1137                                                 res_csize;
1138
1139                                         cur_lte->output_resource_entry.original_size =
1140                                                 cur_lte->resource_entry.original_size;
1141
1142                                         cur_lte->output_resource_entry.offset =
1143                                                 cur_chunk_tab->file_offset;
1144
1145                                         cur_lte->output_resource_entry.flags =
1146                                                 cur_lte->resource_entry.flags |
1147                                                         WIM_RESHDR_FLAG_COMPRESSED;
1148                                 }
1149
1150                                 progress->write_streams.completed_bytes +=
1151                                                 wim_resource_size(cur_lte);
1152                                 progress->write_streams.completed_streams++;
1153
1154                                 if (progress_func) {
1155                                         progress_func(WIMLIB_PROGRESS_MSG_WRITE_STREAMS,
1156                                                       progress);
1157                                 }
1158
1159                                 FREE(cur_chunk_tab);
1160                                 cur_chunk_tab = NULL;
1161
1162                                 struct list_head *next = cur_lte->staging_list.next;
1163                                 list_del(&cur_lte->staging_list);
1164
1165                                 if (next == &outstanding_resources)
1166                                         cur_lte = NULL;
1167                                 else
1168                                         cur_lte = container_of(cur_lte->staging_list.next,
1169                                                                struct wim_lookup_table_entry,
1170                                                                staging_list);
1171
1172                                 // Since we just finished writing a stream,
1173                                 // write any streams that have been added to the
1174                                 // my_resources list for direct writing by the
1175                                 // main thread (e.g. resources that don't need
1176                                 // to be compressed because the desired
1177                                 // compression type is the same as the previous
1178                                 // compression type).
1179                                 ret = do_write_stream_list(&my_resources,
1180                                                            out_fp,
1181                                                            out_ctype,
1182                                                            progress_func,
1183                                                            progress,
1184                                                            0);
1185                                 if (ret != 0)
1186                                         goto out;
1187                         }
1188                 }
1189         }
1190
1191 out:
1192         if (ret == WIMLIB_ERR_NOMEM) {
1193                 ERROR("Could not allocate enough memory for "
1194                       "multi-threaded compression");
1195         }
1196
1197         if (next_lte) {
1198 #ifdef WITH_NTFS_3G
1199                 end_wim_resource_read(next_lte, ni);
1200 #else
1201                 end_wim_resource_read(next_lte);
1202 #endif
1203         }
1204
1205         if (ret == 0) {
1206                 ret = do_write_stream_list(&my_resources, out_fp,
1207                                            out_ctype, progress_func,
1208                                            progress, 0);
1209         } else {
1210                 if (msgs) {
1211                         size_t num_available_msgs = 0;
1212                         struct list_head *cur;
1213
1214                         list_for_each(cur, &available_msgs) {
1215                                 num_available_msgs++;
1216                         }
1217
1218                         while (num_available_msgs < num_messages) {
1219                                 shared_queue_get(compressed_res_queue);
1220                                 num_available_msgs++;
1221                         }
1222                 }
1223         }
1224
1225         if (msgs) {
1226                 for (size_t i = 0; i < num_messages; i++) {
1227                         for (size_t j = 0; j < MAX_CHUNKS_PER_MSG; j++) {
1228                                 FREE(msgs[i].compressed_chunks[j]);
1229                                 FREE(msgs[i].uncompressed_chunks[j]);
1230                         }
1231                 }
1232                 FREE(msgs);
1233         }
1234
1235         FREE(cur_chunk_tab);
1236         return ret;
1237 }
1238
1239 static long
1240 get_default_num_threads()
1241 {
1242 #ifdef __WIN32__
1243         return win32_get_number_of_processors();
1244 #else
1245         return sysconf(_SC_NPROCESSORS_ONLN);
1246 #endif
1247 }
1248
1249 static int
1250 write_stream_list_parallel(struct list_head *stream_list,
1251                            FILE *out_fp,
1252                            int out_ctype,
1253                            int write_flags,
1254                            unsigned num_threads,
1255                            wimlib_progress_func_t progress_func,
1256                            union wimlib_progress_info *progress)
1257 {
1258         int ret;
1259         struct shared_queue res_to_compress_queue;
1260         struct shared_queue compressed_res_queue;
1261         pthread_t *compressor_threads = NULL;
1262
1263         if (num_threads == 0) {
1264                 long nthreads = get_default_num_threads();
1265                 if (nthreads < 1 || nthreads > UINT_MAX) {
1266                         WARNING("Could not determine number of processors! Assuming 1");
1267                         goto out_serial;
1268                 } else {
1269                         num_threads = nthreads;
1270                 }
1271         }
1272
1273         progress->write_streams.num_threads = num_threads;
1274         wimlib_assert(stream_list->next != stream_list);
1275
1276         static const double MESSAGES_PER_THREAD = 2.0;
1277         size_t queue_size = (size_t)(num_threads * MESSAGES_PER_THREAD);
1278
1279         DEBUG("Initializing shared queues (queue_size=%zu)", queue_size);
1280
1281         ret = shared_queue_init(&res_to_compress_queue, queue_size);
1282         if (ret != 0)
1283                 goto out_serial;
1284
1285         ret = shared_queue_init(&compressed_res_queue, queue_size);
1286         if (ret != 0)
1287                 goto out_destroy_res_to_compress_queue;
1288
1289         struct compressor_thread_params params;
1290         params.res_to_compress_queue = &res_to_compress_queue;
1291         params.compressed_res_queue = &compressed_res_queue;
1292         params.compress = get_compress_func(out_ctype);
1293
1294         compressor_threads = MALLOC(num_threads * sizeof(pthread_t));
1295         if (!compressor_threads) {
1296                 ret = WIMLIB_ERR_NOMEM;
1297                 goto out_destroy_compressed_res_queue;
1298         }
1299
1300         for (unsigned i = 0; i < num_threads; i++) {
1301                 DEBUG("pthread_create thread %u", i);
1302                 ret = pthread_create(&compressor_threads[i], NULL,
1303                                      compressor_thread_proc, &params);
1304                 if (ret != 0) {
1305                         ret = -1;
1306                         ERROR_WITH_ERRNO("Failed to create compressor "
1307                                          "thread %u", i);
1308                         num_threads = i;
1309                         goto out_join;
1310                 }
1311         }
1312
1313         if (progress_func)
1314                 progress_func(WIMLIB_PROGRESS_MSG_WRITE_STREAMS, progress);
1315
1316         ret = main_writer_thread_proc(stream_list,
1317                                       out_fp,
1318                                       out_ctype,
1319                                       &res_to_compress_queue,
1320                                       &compressed_res_queue,
1321                                       queue_size,
1322                                       write_flags,
1323                                       progress_func,
1324                                       progress);
1325 out_join:
1326         for (unsigned i = 0; i < num_threads; i++)
1327                 shared_queue_put(&res_to_compress_queue, NULL);
1328
1329         for (unsigned i = 0; i < num_threads; i++) {
1330                 if (pthread_join(compressor_threads[i], NULL)) {
1331                         WARNING_WITH_ERRNO("Failed to join compressor "
1332                                            "thread %u", i);
1333                 }
1334         }
1335         FREE(compressor_threads);
1336 out_destroy_compressed_res_queue:
1337         shared_queue_destroy(&compressed_res_queue);
1338 out_destroy_res_to_compress_queue:
1339         shared_queue_destroy(&res_to_compress_queue);
1340         if (ret >= 0 && ret != WIMLIB_ERR_NOMEM)
1341                 return ret;
1342 out_serial:
1343         WARNING("Falling back to single-threaded compression");
1344         return write_stream_list_serial(stream_list,
1345                                         out_fp,
1346                                         out_ctype,
1347                                         write_flags,
1348                                         progress_func,
1349                                         progress);
1350
1351 }
1352 #endif
1353
1354 /*
1355  * Write a list of streams to a WIM (@out_fp) using the compression type
1356  * @out_ctype and up to @num_threads compressor threads.
1357  */
1358 static int
1359 write_stream_list(struct list_head *stream_list, FILE *out_fp,
1360                   int out_ctype, int write_flags,
1361                   unsigned num_threads,
1362                   wimlib_progress_func_t progress_func)
1363 {
1364         struct wim_lookup_table_entry *lte;
1365         size_t num_streams = 0;
1366         u64 total_bytes = 0;
1367         u64 total_compression_bytes = 0;
1368         union wimlib_progress_info progress;
1369
1370         list_for_each_entry(lte, stream_list, staging_list) {
1371                 num_streams++;
1372                 total_bytes += wim_resource_size(lte);
1373                 if (out_ctype != WIMLIB_COMPRESSION_TYPE_NONE
1374                        && (wim_resource_compression_type(lte) != out_ctype ||
1375                            (write_flags & WIMLIB_WRITE_FLAG_RECOMPRESS)))
1376                 {
1377                         total_compression_bytes += wim_resource_size(lte);
1378                 }
1379         }
1380         progress.write_streams.total_bytes       = total_bytes;
1381         progress.write_streams.total_streams     = num_streams;
1382         progress.write_streams.completed_bytes   = 0;
1383         progress.write_streams.completed_streams = 0;
1384         progress.write_streams.num_threads       = num_threads;
1385         progress.write_streams.compression_type  = out_ctype;
1386
1387 #ifdef ENABLE_MULTITHREADED_COMPRESSION
1388         if (total_compression_bytes >= 1000000 && num_threads != 1)
1389                 return write_stream_list_parallel(stream_list,
1390                                                   out_fp,
1391                                                   out_ctype,
1392                                                   write_flags,
1393                                                   num_threads,
1394                                                   progress_func,
1395                                                   &progress);
1396         else
1397 #endif
1398                 return write_stream_list_serial(stream_list,
1399                                                 out_fp,
1400                                                 out_ctype,
1401                                                 write_flags,
1402                                                 progress_func,
1403                                                 &progress);
1404 }
1405
1406 struct lte_overwrite_prepare_args {
1407         WIMStruct *wim;
1408         off_t end_offset;
1409         struct list_head *stream_list;
1410 };
1411
1412 static int
1413 lte_overwrite_prepare(struct wim_lookup_table_entry *lte, void *arg)
1414 {
1415         struct lte_overwrite_prepare_args *args = arg;
1416
1417         if (lte->resource_location == RESOURCE_IN_WIM &&
1418             lte->wim == args->wim &&
1419             lte->resource_entry.offset + lte->resource_entry.size > args->end_offset)
1420         {
1421         #ifdef ENABLE_ERROR_MESSAGES
1422                 ERROR("The following resource is after the XML data:");
1423                 print_lookup_table_entry(lte, stderr);
1424         #endif
1425                 return WIMLIB_ERR_RESOURCE_ORDER;
1426         }
1427
1428         lte->out_refcnt = lte->refcnt;
1429         memcpy(&lte->output_resource_entry, &lte->resource_entry,
1430                sizeof(struct resource_entry));
1431         if (!(lte->resource_entry.flags & WIM_RESHDR_FLAG_METADATA)) {
1432                 wimlib_assert(lte->resource_location != RESOURCE_NONEXISTENT);
1433                 if (lte->resource_location != RESOURCE_IN_WIM || lte->wim != args->wim)
1434                         list_add(&lte->staging_list, args->stream_list);
1435         }
1436         return 0;
1437 }
1438
1439 static int
1440 wim_find_new_streams(WIMStruct *wim, off_t end_offset,
1441                      struct list_head *stream_list)
1442 {
1443         struct lte_overwrite_prepare_args args = {
1444                 .wim         = wim,
1445                 .end_offset  = end_offset,
1446                 .stream_list = stream_list,
1447         };
1448
1449         return for_lookup_table_entry(wim->lookup_table,
1450                                       lte_overwrite_prepare, &args);
1451 }
1452
1453 static int
1454 inode_find_streams_to_write(struct wim_inode *inode,
1455                             struct wim_lookup_table *table,
1456                             struct list_head *stream_list)
1457 {
1458         struct wim_lookup_table_entry *lte;
1459         for (unsigned i = 0; i <= inode->i_num_ads; i++) {
1460                 lte = inode_stream_lte(inode, i, table);
1461                 if (lte) {
1462                         if (lte->out_refcnt == 0)
1463                                 list_add_tail(&lte->staging_list, stream_list);
1464                         lte->out_refcnt += inode->i_nlink;
1465                 }
1466         }
1467         return 0;
1468 }
1469
1470 static int
1471 image_find_streams_to_write(WIMStruct *w)
1472 {
1473         struct wim_inode *inode;
1474         struct hlist_node *cur;
1475         struct hlist_head *inode_list;
1476
1477         inode_list = &wim_get_current_image_metadata(w)->inode_list;
1478         hlist_for_each_entry(inode, cur, inode_list, i_hlist) {
1479                 inode_find_streams_to_write(inode, w->lookup_table,
1480                                             (struct list_head*)w->private);
1481         }
1482         return 0;
1483 }
1484
1485 static int
1486 write_wim_streams(WIMStruct *w, int image, int write_flags,
1487                              unsigned num_threads,
1488                              wimlib_progress_func_t progress_func)
1489 {
1490
1491         for_lookup_table_entry(w->lookup_table, lte_zero_out_refcnt, NULL);
1492         LIST_HEAD(stream_list);
1493         w->private = &stream_list;
1494         for_image(w, image, image_find_streams_to_write);
1495         return write_stream_list(&stream_list, w->out_fp,
1496                                  wimlib_get_compression_type(w), write_flags,
1497                                  num_threads, progress_func);
1498 }
1499
1500 /*
1501  * Finish writing a WIM file: write the lookup table, xml data, and integrity
1502  * table (optional), then overwrite the WIM header.
1503  *
1504  * write_flags is a bitwise OR of the following:
1505  *
1506  *      (public)  WIMLIB_WRITE_FLAG_CHECK_INTEGRITY:
1507  *              Include an integrity table.
1508  *
1509  *      (public)  WIMLIB_WRITE_FLAG_SHOW_PROGRESS:
1510  *              Show progress information when (if) writing the integrity table.
1511  *
1512  *      (private) WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE:
1513  *              Don't write the lookup table.
1514  *
1515  *      (private) WIMLIB_WRITE_FLAG_REUSE_INTEGRITY_TABLE:
1516  *              When (if) writing the integrity table, re-use entries from the
1517  *              existing integrity table, if possible.
1518  *
1519  *      (private) WIMLIB_WRITE_FLAG_CHECKPOINT_AFTER_XML:
1520  *              After writing the XML data but before writing the integrity
1521  *              table, write a temporary WIM header and flush the stream so that
1522  *              the WIM is less likely to become corrupted upon abrupt program
1523  *              termination.
1524  *
1525  *      (private) WIMLIB_WRITE_FLAG_FSYNC:
1526  *              fsync() the output file before closing it.
1527  *
1528  */
1529 int
1530 finish_write(WIMStruct *w, int image, int write_flags,
1531              wimlib_progress_func_t progress_func)
1532 {
1533         int ret;
1534         struct wim_header hdr;
1535         FILE *out = w->out_fp;
1536
1537         /* @hdr will be the header for the new WIM.  First copy all the data
1538          * from the header in the WIMStruct; then set all the fields that may
1539          * have changed, including the resource entries, boot index, and image
1540          * count.  */
1541         memcpy(&hdr, &w->hdr, sizeof(struct wim_header));
1542
1543         if (!(write_flags & WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE)) {
1544                 ret = write_lookup_table(w->lookup_table, out, &hdr.lookup_table_res_entry);
1545                 if (ret != 0)
1546                         goto out;
1547         }
1548
1549         ret = write_xml_data(w->wim_info, image, out,
1550                              (write_flags & WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE) ?
1551                               wim_info_get_total_bytes(w->wim_info) : 0,
1552                              &hdr.xml_res_entry);
1553         if (ret != 0)
1554                 goto out;
1555
1556         if (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY) {
1557                 if (write_flags & WIMLIB_WRITE_FLAG_CHECKPOINT_AFTER_XML) {
1558                         struct wim_header checkpoint_hdr;
1559                         memcpy(&checkpoint_hdr, &hdr, sizeof(struct wim_header));
1560                         memset(&checkpoint_hdr.integrity, 0, sizeof(struct resource_entry));
1561                         if (fseeko(out, 0, SEEK_SET) != 0) {
1562                                 ERROR_WITH_ERRNO("Failed to seek to beginning "
1563                                                  "of WIM being written");
1564                                 ret = WIMLIB_ERR_WRITE;
1565                                 goto out;
1566                         }
1567                         ret = write_header(&checkpoint_hdr, out);
1568                         if (ret != 0)
1569                                 goto out;
1570
1571                         if (fflush(out) != 0) {
1572                                 ERROR_WITH_ERRNO("Can't write data to WIM");
1573                                 ret = WIMLIB_ERR_WRITE;
1574                                 goto out;
1575                         }
1576
1577                         if (fseeko(out, 0, SEEK_END) != 0) {
1578                                 ERROR_WITH_ERRNO("Failed to seek to end "
1579                                                  "of WIM being written");
1580                                 ret = WIMLIB_ERR_WRITE;
1581                                 goto out;
1582                         }
1583                 }
1584
1585                 off_t old_lookup_table_end;
1586                 off_t new_lookup_table_end;
1587                 if (write_flags & WIMLIB_WRITE_FLAG_REUSE_INTEGRITY_TABLE) {
1588                         old_lookup_table_end = w->hdr.lookup_table_res_entry.offset +
1589                                                w->hdr.lookup_table_res_entry.size;
1590                 } else {
1591                         old_lookup_table_end = 0;
1592                 }
1593                 new_lookup_table_end = hdr.lookup_table_res_entry.offset +
1594                                        hdr.lookup_table_res_entry.size;
1595
1596                 ret = write_integrity_table(out,
1597                                             &hdr.integrity,
1598                                             new_lookup_table_end,
1599                                             old_lookup_table_end,
1600                                             progress_func);
1601                 if (ret != 0)
1602                         goto out;
1603         } else {
1604                 memset(&hdr.integrity, 0, sizeof(struct resource_entry));
1605         }
1606
1607         /*
1608          * In the WIM header, there is room for the resource entry for a
1609          * metadata resource labeled as the "boot metadata".  This entry should
1610          * be zeroed out if there is no bootable image (boot_idx 0).  Otherwise,
1611          * it should be a copy of the resource entry for the image that is
1612          * marked as bootable.  This is not well documented...
1613          */
1614
1615         /* Set image count and boot index correctly for single image writes */
1616         if (image != WIMLIB_ALL_IMAGES) {
1617                 hdr.image_count = 1;
1618                 if (hdr.boot_idx == image)
1619                         hdr.boot_idx = 1;
1620                 else
1621                         hdr.boot_idx = 0;
1622         }
1623
1624         if (hdr.boot_idx == 0) {
1625                 memset(&hdr.boot_metadata_res_entry, 0,
1626                        sizeof(struct resource_entry));
1627         } else {
1628                 memcpy(&hdr.boot_metadata_res_entry,
1629                        &w->image_metadata[
1630                           hdr.boot_idx - 1].metadata_lte->output_resource_entry,
1631                        sizeof(struct resource_entry));
1632         }
1633
1634         if (fseeko(out, 0, SEEK_SET) != 0) {
1635                 ERROR_WITH_ERRNO("Failed to seek to beginning of WIM "
1636                                  "being written");
1637                 ret = WIMLIB_ERR_WRITE;
1638                 goto out;
1639         }
1640
1641         ret = write_header(&hdr, out);
1642         if (ret != 0)
1643                 goto out;
1644
1645         if (write_flags & WIMLIB_WRITE_FLAG_FSYNC) {
1646                 if (fflush(out) != 0
1647                     || fsync(fileno(out)) != 0)
1648                 {
1649                         ERROR_WITH_ERRNO("Error flushing data to WIM file");
1650                         ret = WIMLIB_ERR_WRITE;
1651                 }
1652         }
1653 out:
1654         if (fclose(out) != 0) {
1655                 ERROR_WITH_ERRNO("Failed to close the WIM file");
1656                 if (ret == 0)
1657                         ret = WIMLIB_ERR_WRITE;
1658         }
1659         w->out_fp = NULL;
1660         return ret;
1661 }
1662
1663 #if defined(HAVE_SYS_FILE_H) && defined(HAVE_FLOCK)
1664 int
1665 lock_wim(WIMStruct *w, FILE *fp)
1666 {
1667         int ret = 0;
1668         if (fp && !w->wim_locked) {
1669                 ret = flock(fileno(fp), LOCK_EX | LOCK_NB);
1670                 if (ret != 0) {
1671                         if (errno == EWOULDBLOCK) {
1672                                 ERROR("`%s' is already being modified or has been "
1673                                       "mounted read-write\n"
1674                                       "        by another process!", w->filename);
1675                                 ret = WIMLIB_ERR_ALREADY_LOCKED;
1676                         } else {
1677                                 WARNING_WITH_ERRNO("Failed to lock `%s'",
1678                                                    w->filename);
1679                                 ret = 0;
1680                         }
1681                 } else {
1682                         w->wim_locked = 1;
1683                 }
1684         }
1685         return ret;
1686 }
1687 #endif
1688
1689 static int
1690 open_wim_writable(WIMStruct *w, const mbchar *path,
1691                   bool trunc, bool readable)
1692 {
1693         const char *mode;
1694         if (trunc)
1695                 if (readable)
1696                         mode = "w+b";
1697                 else
1698                         mode = "wb";
1699         else
1700                 mode = "r+b";
1701
1702         wimlib_assert(w->out_fp == NULL);
1703         w->out_fp = fopen(path, mode);
1704         if (w->out_fp) {
1705                 return 0;
1706         } else {
1707                 ERROR_WITH_ERRNO("Failed to open `%s' for writing", path);
1708                 return WIMLIB_ERR_OPEN;
1709         }
1710 }
1711
1712
1713 void
1714 close_wim_writable(WIMStruct *w)
1715 {
1716         if (w->out_fp) {
1717                 if (fclose(w->out_fp) != 0) {
1718                         WARNING_WITH_ERRNO("Failed to close output WIM");
1719                 }
1720                 w->out_fp = NULL;
1721         }
1722 }
1723
1724 /* Open file stream and write dummy header for WIM. */
1725 int
1726 begin_write(WIMStruct *w, const mbchar *path, int write_flags)
1727 {
1728         int ret;
1729         ret = open_wim_writable(w, path, true,
1730                                 (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY) != 0);
1731         if (ret != 0)
1732                 return ret;
1733         /* Write dummy header. It will be overwritten later. */
1734         return write_header(&w->hdr, w->out_fp);
1735 }
1736
1737 /* Writes a stand-alone WIM to a file.  */
1738 WIMLIBAPI int
1739 wimlib_write(WIMStruct *w, const mbchar *path,
1740              int image, int write_flags, unsigned num_threads,
1741              wimlib_progress_func_t progress_func)
1742 {
1743         int ret;
1744
1745         if (!path)
1746                 return WIMLIB_ERR_INVALID_PARAM;
1747
1748         write_flags &= WIMLIB_WRITE_MASK_PUBLIC;
1749
1750         if (image != WIMLIB_ALL_IMAGES &&
1751              (image < 1 || image > w->hdr.image_count))
1752                 return WIMLIB_ERR_INVALID_IMAGE;
1753
1754         if (w->hdr.total_parts != 1) {
1755                 ERROR("Cannot call wimlib_write() on part of a split WIM");
1756                 return WIMLIB_ERR_SPLIT_UNSUPPORTED;
1757         }
1758
1759         ret = begin_write(w, path, write_flags);
1760         if (ret != 0)
1761                 goto out;
1762
1763         ret = write_wim_streams(w, image, write_flags, num_threads,
1764                                 progress_func);
1765         if (ret != 0)
1766                 goto out;
1767
1768         if (progress_func)
1769                 progress_func(WIMLIB_PROGRESS_MSG_WRITE_METADATA_BEGIN, NULL);
1770
1771         ret = for_image(w, image, write_metadata_resource);
1772         if (ret != 0)
1773                 goto out;
1774
1775         if (progress_func)
1776                 progress_func(WIMLIB_PROGRESS_MSG_WRITE_METADATA_END, NULL);
1777
1778         ret = finish_write(w, image, write_flags, progress_func);
1779 out:
1780         close_wim_writable(w);
1781         DEBUG("wimlib_write(path=%s) = %d", path, ret);
1782         return ret;
1783 }
1784
1785 static bool
1786 any_images_modified(WIMStruct *w)
1787 {
1788         for (int i = 0; i < w->hdr.image_count; i++)
1789                 if (w->image_metadata[i].modified)
1790                         return true;
1791         return false;
1792 }
1793
1794 /*
1795  * Overwrite a WIM, possibly appending streams to it.
1796  *
1797  * A WIM looks like (or is supposed to look like) the following:
1798  *
1799  *                   Header (212 bytes)
1800  *                   Streams and metadata resources (variable size)
1801  *                   Lookup table (variable size)
1802  *                   XML data (variable size)
1803  *                   Integrity table (optional) (variable size)
1804  *
1805  * If we are not adding any streams or metadata resources, the lookup table is
1806  * unchanged--- so we only need to overwrite the XML data, integrity table, and
1807  * header.  This operation is potentially unsafe if the program is abruptly
1808  * terminated while the XML data or integrity table are being overwritten, but
1809  * before the new header has been written.  To partially alleviate this problem,
1810  * a special flag (WIMLIB_WRITE_FLAG_CHECKPOINT_AFTER_XML) is passed to
1811  * finish_write() to cause a temporary WIM header to be written after the XML
1812  * data has been written.  This may prevent the WIM from becoming corrupted if
1813  * the program is terminated while the integrity table is being calculated (but
1814  * no guarantees, due to write re-ordering...).
1815  *
1816  * If we are adding new streams or images (metadata resources), the lookup table
1817  * needs to be changed, and those streams need to be written.  In this case, we
1818  * try to perform a safe update of the WIM file by writing the streams *after*
1819  * the end of the previous WIM, then writing the new lookup table, XML data, and
1820  * (optionally) integrity table following the new streams.  This will produce a
1821  * layout like the following:
1822  *
1823  *                   Header (212 bytes)
1824  *                   (OLD) Streams and metadata resources (variable size)
1825  *                   (OLD) Lookup table (variable size)
1826  *                   (OLD) XML data (variable size)
1827  *                   (OLD) Integrity table (optional) (variable size)
1828  *                   (NEW) Streams and metadata resources (variable size)
1829  *                   (NEW) Lookup table (variable size)
1830  *                   (NEW) XML data (variable size)
1831  *                   (NEW) Integrity table (optional) (variable size)
1832  *
1833  * At all points, the WIM is valid as nothing points to the new data yet.  Then,
1834  * the header is overwritten to point to the new lookup table, XML data, and
1835  * integrity table, to produce the following layout:
1836  *
1837  *                   Header (212 bytes)
1838  *                   Streams and metadata resources (variable size)
1839  *                   Nothing (variable size)
1840  *                   More Streams and metadata resources (variable size)
1841  *                   Lookup table (variable size)
1842  *                   XML data (variable size)
1843  *                   Integrity table (optional) (variable size)
1844  *
1845  * This method allows an image to be appended to a large WIM very quickly, and
1846  * is is crash-safe except in the case of write re-ordering, but the
1847  * disadvantage is that a small hole is left in the WIM where the old lookup
1848  * table, xml data, and integrity table were.  (These usually only take up a
1849  * small amount of space compared to the streams, however.)
1850  */
1851 static int
1852 overwrite_wim_inplace(WIMStruct *w, int write_flags,
1853                       unsigned num_threads,
1854                       wimlib_progress_func_t progress_func)
1855 {
1856         int ret;
1857         struct list_head stream_list;
1858         off_t old_wim_end;
1859         bool found_modified_image;
1860
1861         DEBUG("Overwriting `%s' in-place", w->filename);
1862
1863         /* Make sure that the integrity table (if present) is after the XML
1864          * data, and that there are no stream resources, metadata resources, or
1865          * lookup tables after the XML data.  Otherwise, these data would be
1866          * overwritten. */
1867         if (w->hdr.integrity.offset != 0 &&
1868             w->hdr.integrity.offset < w->hdr.xml_res_entry.offset) {
1869                 ERROR("Didn't expect the integrity table to be before the XML data");
1870                 return WIMLIB_ERR_RESOURCE_ORDER;
1871         }
1872
1873         if (w->hdr.lookup_table_res_entry.offset > w->hdr.xml_res_entry.offset) {
1874                 ERROR("Didn't expect the lookup table to be after the XML data");
1875                 return WIMLIB_ERR_RESOURCE_ORDER;
1876         }
1877
1878
1879         if (w->hdr.integrity.offset)
1880                 old_wim_end = w->hdr.integrity.offset + w->hdr.integrity.size;
1881         else
1882                 old_wim_end = w->hdr.xml_res_entry.offset + w->hdr.xml_res_entry.size;
1883
1884         if (!w->deletion_occurred && !any_images_modified(w)) {
1885                 /* If no images have been modified and no images have been
1886                  * deleted, a new lookup table does not need to be written. */
1887                 old_wim_end = w->hdr.lookup_table_res_entry.offset +
1888                               w->hdr.lookup_table_res_entry.size;
1889                 write_flags |= WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE |
1890                                WIMLIB_WRITE_FLAG_CHECKPOINT_AFTER_XML;
1891         }
1892         INIT_LIST_HEAD(&stream_list);
1893         ret = wim_find_new_streams(w, old_wim_end, &stream_list);
1894         if (ret != 0)
1895                 return ret;
1896
1897         ret = open_wim_writable(w, w->filename, false,
1898                                 (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY) != 0);
1899         if (ret != 0)
1900                 return ret;
1901
1902         ret = lock_wim(w, w->out_fp);
1903         if (ret != 0) {
1904                 fclose(w->out_fp);
1905                 w->out_fp = NULL;
1906                 return ret;
1907         }
1908
1909         if (fseeko(w->out_fp, old_wim_end, SEEK_SET) != 0) {
1910                 ERROR_WITH_ERRNO("Can't seek to end of WIM");
1911                 fclose(w->out_fp);
1912                 w->out_fp = NULL;
1913                 w->wim_locked = 0;
1914                 return WIMLIB_ERR_WRITE;
1915         }
1916
1917         if (!list_empty(&stream_list)) {
1918                 DEBUG("Writing newly added streams (offset = %"PRIu64")",
1919                       old_wim_end);
1920                 ret = write_stream_list(&stream_list, w->out_fp,
1921                                         wimlib_get_compression_type(w),
1922                                         write_flags, num_threads,
1923                                         progress_func);
1924                 if (ret != 0)
1925                         goto out_ftruncate;
1926         } else {
1927                 DEBUG("No new streams were added");
1928         }
1929
1930         found_modified_image = false;
1931         for (int i = 0; i < w->hdr.image_count; i++) {
1932                 if (!found_modified_image)
1933                         found_modified_image = w->image_metadata[i].modified;
1934                 if (found_modified_image) {
1935                         select_wim_image(w, i + 1);
1936                         ret = write_metadata_resource(w);
1937                         if (ret != 0)
1938                                 goto out_ftruncate;
1939                 }
1940         }
1941         write_flags |= WIMLIB_WRITE_FLAG_REUSE_INTEGRITY_TABLE;
1942         ret = finish_write(w, WIMLIB_ALL_IMAGES, write_flags,
1943                            progress_func);
1944 out_ftruncate:
1945         close_wim_writable(w);
1946         if (ret != 0 && !(write_flags & WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE)) {
1947                 WARNING("Truncating `%s' to its original size (%"PRIu64" bytes)",
1948                         w->filename, old_wim_end);
1949                 /* Return value of truncate() is ignored because this is already
1950                  * an error path. */
1951                 (void)truncate(w->filename, old_wim_end);
1952         }
1953         w->wim_locked = 0;
1954         return ret;
1955 }
1956
1957 static int
1958 overwrite_wim_via_tmpfile(WIMStruct *w, int write_flags,
1959                           unsigned num_threads,
1960                           wimlib_progress_func_t progress_func)
1961 {
1962         size_t wim_name_len;
1963         int ret;
1964
1965         DEBUG("Overwriting `%s' via a temporary file", w->filename);
1966
1967         /* Write the WIM to a temporary file in the same directory as the
1968          * original WIM. */
1969         wim_name_len = strlen(w->filename);
1970         mbchar tmpfile[wim_name_len + 10];
1971         memcpy(tmpfile, w->filename, wim_name_len);
1972         randomize_char_array_with_alnum(tmpfile + wim_name_len, 9);
1973         tmpfile[wim_name_len + 9] = '\0';
1974
1975         ret = wimlib_write(w, tmpfile, WIMLIB_ALL_IMAGES,
1976                            write_flags | WIMLIB_WRITE_FLAG_FSYNC,
1977                            num_threads, progress_func);
1978         if (ret != 0) {
1979                 ERROR("Failed to write the WIM file `%s'", tmpfile);
1980                 goto err;
1981         }
1982
1983         DEBUG("Renaming `%s' to `%s'", tmpfile, w->filename);
1984
1985 #ifdef __WIN32__
1986         /* Windows won't let you delete open files unless FILE_SHARE_DELETE was
1987          * specified to CreateFile().  The WIM was opened with fopen(), which
1988          * didn't provided this flag to CreateFile, so the handle must be closed
1989          * before executing the rename(). */
1990         if (w->fp != NULL) {
1991                 fclose(w->fp);
1992                 w->fp = NULL;
1993         }
1994 #endif
1995
1996         /* Rename the new file to the old file .*/
1997         if (rename(tmpfile, w->filename) != 0) {
1998                 ERROR_WITH_ERRNO("Failed to rename `%s' to `%s'",
1999                                  tmpfile, w->filename);
2000                 ret = WIMLIB_ERR_RENAME;
2001                 goto err;
2002         }
2003
2004         if (progress_func) {
2005                 union wimlib_progress_info progress;
2006                 progress.rename.from = tmpfile;
2007                 progress.rename.to = w->filename;
2008                 progress_func(WIMLIB_PROGRESS_MSG_RENAME, &progress);
2009         }
2010
2011         /* Close the original WIM file that was opened for reading. */
2012         if (w->fp != NULL) {
2013                 fclose(w->fp);
2014                 w->fp = NULL;
2015         }
2016
2017         /* Re-open the WIM read-only. */
2018         w->fp = fopen(w->filename, "rb");
2019         if (w->fp == NULL) {
2020                 ret = WIMLIB_ERR_REOPEN;
2021                 WARNING_WITH_ERRNO("Failed to re-open `%s' read-only",
2022                                    w->filename);
2023                 FREE(w->filename);
2024                 w->filename = NULL;
2025         }
2026         return ret;
2027 err:
2028         /* Remove temporary file. */
2029         if (unlink(tmpfile) != 0)
2030                 WARNING_WITH_ERRNO("Failed to remove `%s'", tmpfile);
2031         return ret;
2032 }
2033
2034 /*
2035  * Writes a WIM file to the original file that it was read from, overwriting it.
2036  */
2037 WIMLIBAPI int
2038 wimlib_overwrite(WIMStruct *w, int write_flags,
2039                  unsigned num_threads,
2040                  wimlib_progress_func_t progress_func)
2041 {
2042         write_flags &= WIMLIB_WRITE_MASK_PUBLIC;
2043
2044         if (!w->filename)
2045                 return WIMLIB_ERR_NO_FILENAME;
2046
2047         if (w->hdr.total_parts != 1) {
2048                 ERROR("Cannot modify a split WIM");
2049                 return WIMLIB_ERR_SPLIT_UNSUPPORTED;
2050         }
2051
2052         if ((!w->deletion_occurred || (write_flags & WIMLIB_WRITE_FLAG_SOFT_DELETE))
2053             && !(write_flags & WIMLIB_WRITE_FLAG_REBUILD))
2054         {
2055                 int ret;
2056                 ret = overwrite_wim_inplace(w, write_flags, num_threads,
2057                                             progress_func);
2058                 if (ret == WIMLIB_ERR_RESOURCE_ORDER)
2059                         WARNING("Falling back to re-building entire WIM");
2060                 else
2061                         return ret;
2062         }
2063         return overwrite_wim_via_tmpfile(w, write_flags, num_threads,
2064                                          progress_func);
2065 }