Don't create unnecessary temporary files
[wimlib] / 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 #ifdef HAVE_CONFIG_H
28 #  include "config.h"
29 #endif
30
31 #if defined(HAVE_SYS_FILE_H) && defined(HAVE_FLOCK)
32 /* On BSD, this should be included before "wimlib/list.h" so that "wimlib/list.h" can
33  * overwrite the LIST_HEAD macro. */
34 #  include <sys/file.h>
35 #endif
36
37 #include "wimlib/chunk_compressor.h"
38 #include "wimlib/endianness.h"
39 #include "wimlib/error.h"
40 #include "wimlib/file_io.h"
41 #include "wimlib/header.h"
42 #include "wimlib/inode.h"
43 #include "wimlib/integrity.h"
44 #include "wimlib/lookup_table.h"
45 #include "wimlib/metadata.h"
46 #include "wimlib/resource.h"
47 #ifdef __WIN32__
48 #  include "wimlib/win32.h" /* win32_rename_replacement() */
49 #endif
50 #include "wimlib/write.h"
51 #include "wimlib/xml.h"
52
53 #include <errno.h>
54 #include <fcntl.h>
55 #include <stdlib.h>
56 #include <unistd.h>
57
58 #ifdef HAVE_ALLOCA_H
59 #  include <alloca.h>
60 #endif
61
62 /* wimlib internal flags used when writing resources.  */
63 #define WRITE_RESOURCE_FLAG_RECOMPRESS          0x00000001
64 #define WRITE_RESOURCE_FLAG_PIPABLE             0x00000002
65 #define WRITE_RESOURCE_FLAG_PACK_STREAMS        0x00000004
66
67 static inline int
68 write_flags_to_resource_flags(int write_flags)
69 {
70         int write_resource_flags = 0;
71
72         if (write_flags & WIMLIB_WRITE_FLAG_RECOMPRESS)
73                 write_resource_flags |= WRITE_RESOURCE_FLAG_RECOMPRESS;
74         if (write_flags & WIMLIB_WRITE_FLAG_PIPABLE)
75                 write_resource_flags |= WRITE_RESOURCE_FLAG_PIPABLE;
76         if (write_flags & WIMLIB_WRITE_FLAG_PACK_STREAMS)
77                 write_resource_flags |= WRITE_RESOURCE_FLAG_PACK_STREAMS;
78         return write_resource_flags;
79 }
80
81 struct filter_context {
82         int write_flags;
83         WIMStruct *wim;
84 };
85
86 /* Determine specified stream should be filtered out from the write.
87  *
88  * Return values:
89  *
90  *  < 0 : The stream should be hard-filtered; that is, not included in the
91  *        output WIM at all.
92  *    0 : The stream should not be filtered out.
93  *  > 0 : The stream should be soft-filtered; that is, it already exists in the
94  *        WIM file and may not need to be written again.
95  */
96 static int
97 stream_filtered(const struct wim_lookup_table_entry *lte,
98                 const struct filter_context *ctx)
99 {
100         int write_flags = ctx->write_flags;
101         WIMStruct *wim = ctx->wim;
102
103         if (ctx == NULL)
104                 return 0;
105
106         if (write_flags & WIMLIB_WRITE_FLAG_OVERWRITE &&
107             lte->resource_location == RESOURCE_IN_WIM &&
108             lte->rspec->wim == wim)
109                 return 1;
110
111         if (write_flags & WIMLIB_WRITE_FLAG_SKIP_EXTERNAL_WIMS &&
112             lte->resource_location == RESOURCE_IN_WIM &&
113             lte->rspec->wim != wim)
114                 return -1;
115
116         return 0;
117 }
118
119 static bool
120 stream_hard_filtered(const struct wim_lookup_table_entry *lte,
121                      struct filter_context *ctx)
122 {
123         return stream_filtered(lte, ctx) < 0;
124 }
125
126 static inline int
127 may_soft_filter_streams(const struct filter_context *ctx)
128 {
129         if (ctx == NULL)
130                 return 0;
131         return ctx->write_flags & WIMLIB_WRITE_FLAG_OVERWRITE;
132 }
133
134 static inline int
135 may_hard_filter_streams(const struct filter_context *ctx)
136 {
137         if (ctx == NULL)
138                 return 0;
139         return ctx->write_flags & WIMLIB_WRITE_FLAG_SKIP_EXTERNAL_WIMS;
140 }
141
142 static inline int
143 may_filter_streams(const struct filter_context *ctx)
144 {
145         return (may_soft_filter_streams(ctx) ||
146                 may_hard_filter_streams(ctx));
147 }
148
149
150 /* Return true if the specified resource is compressed and the compressed data
151  * can be reused with the specified output parameters.  */
152 static bool
153 can_raw_copy(const struct wim_lookup_table_entry *lte,
154              int write_resource_flags, int out_ctype, u32 out_chunk_size)
155 {
156         const struct wim_resource_spec *rspec;
157
158         if (write_resource_flags & WRITE_RESOURCE_FLAG_RECOMPRESS)
159                 return false;
160
161         if (out_ctype == WIMLIB_COMPRESSION_TYPE_NONE)
162                 return false;
163
164         if (lte->resource_location != RESOURCE_IN_WIM)
165                 return false;
166
167         rspec = lte->rspec;
168
169         if (rspec->is_pipable != !!(write_resource_flags & WRITE_RESOURCE_FLAG_PIPABLE))
170                 return false;
171
172         if (rspec->flags & WIM_RESHDR_FLAG_COMPRESSED) {
173                 /* Normal compressed resource: Must use same compression type
174                  * and chunk size.  */
175                 return (rspec->compression_type == out_ctype &&
176                         rspec->chunk_size == out_chunk_size);
177         }
178
179         if ((rspec->flags & WIM_RESHDR_FLAG_PACKED_STREAMS) &&
180             (write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS))
181         {
182                 /* Packed resource: Such resources may contain multiple streams,
183                  * and in general only a subset of them need to be written.  As
184                  * a heuristic, re-use the raw data if more than two-thirds the
185                  * uncompressed size is being written.  */
186
187                 /* Note: packed resources contain a header that specifies the
188                  * compression type and chunk size; therefore we don't need to
189                  * check if they are compatible with @out_ctype and
190                  * @out_chunk_size.  */
191
192                 struct wim_lookup_table_entry *res_stream;
193                 u64 write_size = 0;
194
195                 list_for_each_entry(res_stream, &rspec->stream_list, rspec_node)
196                         if (res_stream->will_be_in_output_wim)
197                                 write_size += res_stream->size;
198
199                 return (write_size > rspec->uncompressed_size * 2 / 3);
200         }
201
202         return false;
203 }
204
205 static u8
206 filter_resource_flags(u8 flags)
207 {
208         return (flags & ~(WIM_RESHDR_FLAG_PACKED_STREAMS |
209                           WIM_RESHDR_FLAG_COMPRESSED |
210                           WIM_RESHDR_FLAG_SPANNED |
211                           WIM_RESHDR_FLAG_FREE));
212 }
213
214 static void
215 stream_set_out_reshdr_for_reuse(struct wim_lookup_table_entry *lte)
216 {
217         const struct wim_resource_spec *rspec;
218
219         wimlib_assert(lte->resource_location == RESOURCE_IN_WIM);
220         rspec = lte->rspec;
221
222         if (rspec->flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
223
224                 wimlib_assert(lte->flags & WIM_RESHDR_FLAG_PACKED_STREAMS);
225
226                 lte->out_reshdr.offset_in_wim = lte->offset_in_res;
227                 lte->out_reshdr.uncompressed_size = 0;
228                 lte->out_reshdr.size_in_wim = lte->size;
229
230                 lte->out_res_offset_in_wim = rspec->offset_in_wim;
231                 lte->out_res_size_in_wim = rspec->size_in_wim;
232                 lte->out_res_uncompressed_size = rspec->uncompressed_size;
233         } else {
234                 wimlib_assert(!(lte->flags & WIM_RESHDR_FLAG_PACKED_STREAMS));
235
236                 lte->out_reshdr.offset_in_wim = rspec->offset_in_wim;
237                 lte->out_reshdr.uncompressed_size = rspec->uncompressed_size;
238                 lte->out_reshdr.size_in_wim = rspec->size_in_wim;
239         }
240         lte->out_reshdr.flags = lte->flags;
241 }
242
243
244 /* Write the header for a stream in a pipable WIM.  */
245 static int
246 write_pwm_stream_header(const struct wim_lookup_table_entry *lte,
247                         struct filedes *out_fd,
248                         int additional_reshdr_flags)
249 {
250         struct pwm_stream_hdr stream_hdr;
251         u32 reshdr_flags;
252         int ret;
253
254         stream_hdr.magic = cpu_to_le64(PWM_STREAM_MAGIC);
255         stream_hdr.uncompressed_size = cpu_to_le64(lte->size);
256         if (additional_reshdr_flags & PWM_RESHDR_FLAG_UNHASHED) {
257                 zero_out_hash(stream_hdr.hash);
258         } else {
259                 wimlib_assert(!lte->unhashed);
260                 copy_hash(stream_hdr.hash, lte->hash);
261         }
262
263         reshdr_flags = filter_resource_flags(lte->flags);
264         reshdr_flags |= additional_reshdr_flags;
265         stream_hdr.flags = cpu_to_le32(reshdr_flags);
266         ret = full_write(out_fd, &stream_hdr, sizeof(stream_hdr));
267         if (ret)
268                 ERROR_WITH_ERRNO("Write error");
269         return ret;
270 }
271
272 struct write_streams_progress_data {
273         wimlib_progress_func_t progress_func;
274         union wimlib_progress_info progress;
275         uint64_t next_progress;
276 };
277
278 static void
279 do_write_streams_progress(struct write_streams_progress_data *progress_data,
280                           struct wim_lookup_table_entry *cur_stream,
281                           u64 complete_size,
282                           u32 complete_count,
283                           bool discarded)
284 {
285         union wimlib_progress_info *progress = &progress_data->progress;
286
287         if (discarded) {
288                 progress->write_streams.total_bytes -= complete_size;
289                 progress->write_streams.total_streams -= complete_count;
290                 if (progress_data->next_progress != ~(uint64_t)0 &&
291                     progress_data->next_progress > progress->write_streams.total_bytes)
292                 {
293                         progress_data->next_progress = progress->write_streams.total_bytes;
294                 }
295         } else {
296                 progress->write_streams.completed_bytes += complete_size;
297                 progress->write_streams.completed_streams += complete_count;
298         }
299
300         if (progress_data->progress_func
301             && (progress->write_streams.completed_bytes >= progress_data->next_progress))
302         {
303                 progress_data->progress_func(WIMLIB_PROGRESS_MSG_WRITE_STREAMS,
304                                              progress);
305                 if (progress_data->next_progress == progress->write_streams.total_bytes) {
306                         progress_data->next_progress = ~(uint64_t)0;
307                 } else {
308                         progress_data->next_progress =
309                                 min(progress->write_streams.total_bytes,
310                                     progress->write_streams.completed_bytes +
311                                         progress->write_streams.total_bytes / 100);
312                 }
313         }
314 }
315
316 struct write_streams_ctx {
317         /* File descriptor the streams are being written to.  */
318         struct filedes *out_fd;
319
320         /* Lookup table for the WIMStruct on whose behalf the streams are being
321          * written.  */
322         struct wim_lookup_table *lookup_table;
323
324         /* Compression format to use.  */
325         int out_ctype;
326
327         /* Maximum uncompressed chunk size in compressed resources to use.  */
328         u32 out_chunk_size;
329
330         /* Flags that affect how the streams will be written.  */
331         int write_resource_flags;
332
333         /* Data used for issuing WRITE_STREAMS progress.  */
334         struct write_streams_progress_data progress_data;
335
336         struct filter_context *filter_ctx;
337
338         /* Upper bound on the total number of bytes that need to be compressed.
339          * */
340         u64 num_bytes_to_compress;
341
342         /* Pointer to the chunk_compressor implementation being used for
343          * compressing chunks of data, or NULL if chunks are being written
344          * uncompressed.  */
345         struct chunk_compressor *compressor;
346
347         /* Buffer for dividing the read data into chunks of size
348          * @out_chunk_size.  */
349         u8 *chunk_buf;
350
351         /* Number of bytes in @chunk_buf that are currently filled.  */
352         size_t chunk_buf_filled;
353
354         /* List of streams that currently have chunks being compressed.  */
355         struct list_head pending_streams;
356
357         /* List of streams in the resource pack.  Streams are moved here after
358          * @pending_streams only when writing a packed resource.  */
359         struct list_head pack_streams;
360
361         /* Set to true if the stream currently being read was a duplicate, and
362          * therefore the corresponding stream entry needs to be freed once the
363          * read finishes.  (In this case we add the duplicate entry to
364          * pending_streams rather than the entry being read.)  */
365         bool stream_was_duplicate;
366
367         /* Current uncompressed offset in the stream being read.  */
368         u64 cur_read_stream_offset;
369
370         /* Uncompressed size of the stream currently being read.  */
371         u64 cur_read_stream_size;
372
373         /* Current uncompressed offset in the stream being written.  */
374         u64 cur_write_stream_offset;
375
376         /* Uncompressed size of resource currently being written.  */
377         u64 cur_write_res_size;
378
379         /* Array that is filled in with compressed chunk sizes as a resource is
380          * being written.  */
381         u64 *chunk_csizes;
382
383         /* Index of next entry in @chunk_csizes to fill in.  */
384         size_t chunk_index;
385
386         /* Number of entries in @chunk_csizes currently allocated.  */
387         size_t num_alloc_chunks;
388
389         /* Offset in the output file of the start of the chunks of the resource
390          * currently being written.  */
391         u64 chunks_start_offset;
392 };
393
394 /* Reserve space for the chunk table and prepare to accumulate the chunk table
395  * in memory.  */
396 static int
397 begin_chunk_table(struct write_streams_ctx *ctx, u64 res_expected_size)
398 {
399         u64 expected_num_chunks;
400         u64 expected_num_chunk_entries;
401         size_t reserve_size;
402         int ret;
403
404         /* Calculate the number of chunks and chunk entries that should be
405          * needed for the resource.  These normally will be the final values,
406          * but in PACKED_STREAMS mode some of the streams we're planning to
407          * write into the resource may be duplicates, and therefore discarded,
408          * potentially decreasing the number of chunk entries needed.  */
409         expected_num_chunks = DIV_ROUND_UP(res_expected_size, ctx->out_chunk_size);
410         expected_num_chunk_entries = expected_num_chunks;
411         if (!(ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS))
412                 expected_num_chunk_entries--;
413
414         /* Make sure the chunk_csizes array is long enough to store the
415          * compressed size of each chunk.  */
416         if (expected_num_chunks > ctx->num_alloc_chunks) {
417                 u64 new_length = expected_num_chunks + 50;
418
419                 if ((size_t)new_length != new_length) {
420                         ERROR("Resource size too large (%"PRIu64" bytes!",
421                               res_expected_size);
422                         return WIMLIB_ERR_NOMEM;
423                 }
424
425                 FREE(ctx->chunk_csizes);
426                 ctx->chunk_csizes = MALLOC(new_length * sizeof(ctx->chunk_csizes[0]));
427                 if (ctx->chunk_csizes == NULL) {
428                         ctx->num_alloc_chunks = 0;
429                         return WIMLIB_ERR_NOMEM;
430                 }
431                 ctx->num_alloc_chunks = new_length;
432         }
433
434         ctx->chunk_index = 0;
435
436         if (!(ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PIPABLE)) {
437                 /* Reserve space for the chunk table in the output file.  In the
438                  * case of packed resources this reserves the upper bound for
439                  * the needed space, not necessarily the exact space which will
440                  * prove to be needed.  At this point, we just use @chunk_csizes
441                  * for a buffer of 0's because the actual compressed chunk sizes
442                  * are unknown.  */
443                 reserve_size = expected_num_chunk_entries *
444                                get_chunk_entry_size(res_expected_size,
445                                                     0 != (ctx->write_resource_flags &
446                                                           WIM_RESHDR_FLAG_PACKED_STREAMS));
447                 if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS)
448                         reserve_size += sizeof(struct alt_chunk_table_header_disk);
449                 memset(ctx->chunk_csizes, 0, reserve_size);
450                 ret = full_write(ctx->out_fd, ctx->chunk_csizes, reserve_size);
451                 if (ret)
452                         return ret;
453         }
454         return 0;
455 }
456
457 static int
458 begin_write_resource(struct write_streams_ctx *ctx, u64 res_expected_size)
459 {
460         int ret;
461
462         wimlib_assert(res_expected_size != 0);
463
464         if (ctx->compressor != NULL) {
465                 ret = begin_chunk_table(ctx, res_expected_size);
466                 if (ret)
467                         return ret;
468         }
469
470         /* Output file descriptor is now positioned at the offset at which to
471          * write the first chunk of the resource.  */
472         ctx->chunks_start_offset = ctx->out_fd->offset;
473         ctx->cur_write_stream_offset = 0;
474         ctx->cur_write_res_size = res_expected_size;
475         return 0;
476 }
477
478 static int
479 end_chunk_table(struct write_streams_ctx *ctx, u64 res_actual_size,
480                 u64 *res_start_offset_ret, u64 *res_store_size_ret)
481 {
482         size_t actual_num_chunks;
483         size_t actual_num_chunk_entries;
484         size_t chunk_entry_size;
485         int ret;
486
487         actual_num_chunks = ctx->chunk_index;
488         actual_num_chunk_entries = actual_num_chunks;
489         if (!(ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS))
490                 actual_num_chunk_entries--;
491
492         chunk_entry_size = get_chunk_entry_size(res_actual_size,
493                                                 0 != (ctx->write_resource_flags &
494                                                       WIM_RESHDR_FLAG_PACKED_STREAMS));
495
496         typedef le64 __attribute__((may_alias)) aliased_le64_t;
497         typedef le32 __attribute__((may_alias)) aliased_le32_t;
498
499         if (chunk_entry_size == 4) {
500                 aliased_le32_t *entries = (aliased_le32_t*)ctx->chunk_csizes;
501
502                 if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS) {
503                         for (size_t i = 0; i < actual_num_chunk_entries; i++)
504                                 entries[i] = cpu_to_le32(ctx->chunk_csizes[i]);
505                 } else {
506                         u32 offset = ctx->chunk_csizes[0];
507                         for (size_t i = 0; i < actual_num_chunk_entries; i++) {
508                                 u32 next_size = ctx->chunk_csizes[i + 1];
509                                 entries[i] = cpu_to_le32(offset);
510                                 offset += next_size;
511                         }
512                 }
513         } else {
514                 aliased_le64_t *entries = (aliased_le64_t*)ctx->chunk_csizes;
515
516                 if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS) {
517                         for (size_t i = 0; i < actual_num_chunk_entries; i++)
518                                 entries[i] = cpu_to_le64(ctx->chunk_csizes[i]);
519                 } else {
520                         u64 offset = ctx->chunk_csizes[0];
521                         for (size_t i = 0; i < actual_num_chunk_entries; i++) {
522                                 u64 next_size = ctx->chunk_csizes[i + 1];
523                                 entries[i] = cpu_to_le64(offset);
524                                 offset += next_size;
525                         }
526                 }
527         }
528
529         size_t chunk_table_size = actual_num_chunk_entries * chunk_entry_size;
530         u64 res_start_offset;
531         u64 res_end_offset;
532
533         if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PIPABLE) {
534                 ret = full_write(ctx->out_fd, ctx->chunk_csizes, chunk_table_size);
535                 if (ret)
536                         goto error;
537                 res_end_offset = ctx->out_fd->offset;
538                 res_start_offset = ctx->chunks_start_offset;
539         } else {
540                 res_end_offset = ctx->out_fd->offset;
541
542                 u64 chunk_table_offset;
543
544                 chunk_table_offset = ctx->chunks_start_offset - chunk_table_size;
545
546                 if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS) {
547                         struct alt_chunk_table_header_disk hdr;
548
549                         hdr.res_usize = cpu_to_le64(res_actual_size);
550                         hdr.chunk_size = cpu_to_le32(ctx->out_chunk_size);
551                         hdr.compression_format = cpu_to_le32(ctx->out_ctype);
552
553                         BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_XPRESS != 1);
554                         BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_LZX != 2);
555                         BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_LZMS != 3);
556
557                         ret = full_pwrite(ctx->out_fd, &hdr, sizeof(hdr),
558                                           chunk_table_offset - sizeof(hdr));
559                         if (ret)
560                                 goto error;
561                         res_start_offset = chunk_table_offset - sizeof(hdr);
562                 } else {
563                         res_start_offset = chunk_table_offset;
564                 }
565
566                 ret = full_pwrite(ctx->out_fd, ctx->chunk_csizes,
567                                   chunk_table_size, chunk_table_offset);
568                 if (ret)
569                         goto error;
570         }
571
572         *res_start_offset_ret = res_start_offset;
573         *res_store_size_ret = res_end_offset - res_start_offset;
574
575         return 0;
576
577 error:
578         ERROR_WITH_ERRNO("Write error");
579         return ret;
580 }
581
582 /* Finish writing a WIM resource by writing or updating the chunk table (if not
583  * writing the data uncompressed) and loading its metadata into @out_reshdr.  */
584 static int
585 end_write_resource(struct write_streams_ctx *ctx, struct wim_reshdr *out_reshdr)
586 {
587         int ret;
588         u64 res_size_in_wim;
589         u64 res_uncompressed_size;
590         u64 res_offset_in_wim;
591
592         wimlib_assert(ctx->cur_write_stream_offset == ctx->cur_write_res_size ||
593                       (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS));
594         res_uncompressed_size = ctx->cur_write_res_size;
595
596         if (ctx->compressor) {
597                 ret = end_chunk_table(ctx, res_uncompressed_size,
598                                       &res_offset_in_wim, &res_size_in_wim);
599                 if (ret)
600                         return ret;
601         } else {
602                 res_offset_in_wim = ctx->chunks_start_offset;
603                 res_size_in_wim = ctx->out_fd->offset - res_offset_in_wim;
604         }
605         out_reshdr->uncompressed_size = res_uncompressed_size;
606         out_reshdr->size_in_wim = res_size_in_wim;
607         out_reshdr->offset_in_wim = res_offset_in_wim;
608         DEBUG("Finished writing resource: %"PRIu64" => %"PRIu64" @ %"PRIu64"",
609               res_uncompressed_size, res_size_in_wim, res_offset_in_wim);
610         return 0;
611 }
612
613 /* Begin processing a stream for writing.  */
614 static int
615 write_stream_begin_read(struct wim_lookup_table_entry *lte,
616                         u32 flags, void *_ctx)
617 {
618         struct write_streams_ctx *ctx = _ctx;
619         int ret;
620
621         wimlib_assert(lte->size > 0);
622
623         ctx->cur_read_stream_offset = 0;
624         ctx->cur_read_stream_size = lte->size;
625
626         /* As an optimization, we allow some streams to be "unhashed", meaning
627          * their SHA1 message digests are unknown.  This is the case with
628          * streams that are added by scanning a directry tree with
629          * wimlib_add_image(), for example.  Since WIM uses single-instance
630          * streams, we don't know whether such each such stream really need to
631          * written until it is actually checksummed, unless it has a unique
632          * size.  In such cases we read and checksum the stream in this
633          * function, thereby advancing ahead of read_stream_list(), which will
634          * still provide the data again to write_stream_process_chunk().  This
635          * is okay because an unhashed stream cannot be in a WIM resource, which
636          * might be costly to decompress.  */
637         ctx->stream_was_duplicate = false;
638         if (ctx->lookup_table != NULL && lte->unhashed && !lte->unique_size) {
639
640                 wimlib_assert(!(flags & BEGIN_STREAM_FLAG_PARTIAL_RESOURCE));
641
642                 struct wim_lookup_table_entry *lte_new;
643
644                 ret = hash_unhashed_stream(lte, ctx->lookup_table, &lte_new);
645                 if (ret)
646                         return ret;
647                 if (lte_new != lte) {
648                         /* Duplicate stream detected.  */
649
650                         if (lte_new->will_be_in_output_wim ||
651                             stream_filtered(lte_new, ctx->filter_ctx))
652                         {
653                                 /* The duplicate stream is already being
654                                  * included in the output WIM, or it would be
655                                  * filtered out if it had been.  Skip writing
656                                  * this stream (and reading it again) entirely,
657                                  * passing its output reference count to the
658                                  * duplicate stream in the former case.  */
659                                 DEBUG("Discarding duplicate stream of "
660                                       "length %"PRIu64, lte->size);
661                                 do_write_streams_progress(&ctx->progress_data,
662                                                           lte, lte->size,
663                                                           1, true);
664                                 list_del(&lte->write_streams_list);
665                                 list_del(&lte->lookup_table_list);
666                                 if (lte_new->will_be_in_output_wim)
667                                         lte_new->out_refcnt += lte->out_refcnt;
668                                 if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS)
669                                         ctx->cur_write_res_size -= lte->size;
670                                 free_lookup_table_entry(lte);
671                                 return BEGIN_STREAM_STATUS_SKIP_STREAM;
672                         } else {
673                                 /* The duplicate stream can validly be written,
674                                  * but was not marked as such.  Discard the
675                                  * current stream entry and use the duplicate,
676                                  * but actually freeing the current entry must
677                                  * wait until read_stream_list() has finished
678                                  * reading its data.  */
679                                 DEBUG("Stream duplicate, but not already "
680                                       "selected for writing.");
681                                 list_replace(&lte->write_streams_list,
682                                              &lte_new->write_streams_list);
683                                 list_replace(&lte->lookup_table_list,
684                                              &lte_new->lookup_table_list);
685                                 lte_new->out_refcnt = lte->out_refcnt;
686                                 lte_new->will_be_in_output_wim = 1;
687                                 ctx->stream_was_duplicate = true;
688                                 lte = lte_new;
689                         }
690                 }
691         }
692         list_move_tail(&lte->write_streams_list, &ctx->pending_streams);
693         return 0;
694 }
695
696 /* Rewrite a stream that was just written compressed as uncompressed instead.
697  * This function is optional, but if a stream did not compress to less than its
698  * original size, it might as well be written uncompressed.  */
699 static int
700 write_stream_uncompressed(struct wim_lookup_table_entry *lte,
701                           struct filedes *out_fd)
702 {
703         int ret;
704         u64 begin_offset = lte->out_reshdr.offset_in_wim;
705         u64 end_offset = out_fd->offset;
706
707         if (filedes_seek(out_fd, begin_offset) == -1)
708                 return 0;
709
710         ret = extract_full_stream_to_fd(lte, out_fd);
711         if (ret) {
712                 /* Error reading the uncompressed data.  */
713                 if (out_fd->offset == begin_offset &&
714                     filedes_seek(out_fd, end_offset) != -1)
715                 {
716                         /* Nothing was actually written yet, and we successfully
717                          * seeked to the end of the compressed resource, so
718                          * don't issue a hard error; just keep the compressed
719                          * resource instead.  */
720                         WARNING("Recovered compressed stream of "
721                                 "size %"PRIu64", continuing on.",
722                                 lte->size);
723                         return 0;
724                 }
725                 return ret;
726         }
727
728         wimlib_assert(out_fd->offset - begin_offset == lte->size);
729
730         if (out_fd->offset < end_offset &&
731             0 != ftruncate(out_fd->fd, out_fd->offset))
732         {
733                 ERROR_WITH_ERRNO("Can't truncate output file to "
734                                  "offset %"PRIu64, out_fd->offset);
735                 return WIMLIB_ERR_WRITE;
736         }
737
738         lte->out_reshdr.size_in_wim = lte->size;
739         lte->out_reshdr.flags &= ~(WIM_RESHDR_FLAG_COMPRESSED |
740                                    WIM_RESHDR_FLAG_PACKED_STREAMS);
741         return 0;
742 }
743
744 /* Write the next chunk of (typically compressed) data to the output WIM,
745  * handling the writing of the chunk table.  */
746 static int
747 write_chunk(struct write_streams_ctx *ctx, const void *cchunk,
748             size_t csize, size_t usize)
749 {
750         int ret;
751
752         struct wim_lookup_table_entry *lte;
753         u32 completed_stream_count;
754         u32 completed_size;
755
756         lte = list_entry(ctx->pending_streams.next,
757                          struct wim_lookup_table_entry, write_streams_list);
758
759         if (ctx->cur_write_stream_offset == 0 &&
760             !(ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS))
761         {
762                 /* Starting to write a new stream in non-packed mode.  */
763
764                 if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PIPABLE) {
765                         int additional_reshdr_flags = 0;
766                         if (ctx->compressor != NULL)
767                                 additional_reshdr_flags |= WIM_RESHDR_FLAG_COMPRESSED;
768
769                         DEBUG("Writing pipable WIM stream header "
770                               "(offset=%"PRIu64")", ctx->out_fd->offset);
771
772                         ret = write_pwm_stream_header(lte, ctx->out_fd,
773                                                       additional_reshdr_flags);
774                         if (ret)
775                                 return ret;
776                 }
777
778                 ret = begin_write_resource(ctx, lte->size);
779                 if (ret)
780                         return ret;
781         }
782
783         if (ctx->compressor != NULL) {
784                 /* Record the compresed chunk size.  */
785                 wimlib_assert(ctx->chunk_index < ctx->num_alloc_chunks);
786                 ctx->chunk_csizes[ctx->chunk_index++] = csize;
787
788                /* If writing a pipable WIM, before the chunk data write a chunk
789                 * header that provides the compressed chunk size.  */
790                 if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PIPABLE) {
791                         struct pwm_chunk_hdr chunk_hdr = {
792                                 .compressed_size = cpu_to_le32(csize),
793                         };
794                         ret = full_write(ctx->out_fd, &chunk_hdr,
795                                          sizeof(chunk_hdr));
796                         if (ret)
797                                 goto error;
798                 }
799         }
800
801         /* Write the chunk data.  */
802         ret = full_write(ctx->out_fd, cchunk, csize);
803         if (ret)
804                 goto error;
805
806         ctx->cur_write_stream_offset += usize;
807
808         completed_size = usize;
809         completed_stream_count = 0;
810         if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS) {
811                 /* Wrote chunk in packed mode.  It may have finished multiple
812                  * streams.  */
813                 while (ctx->cur_write_stream_offset > lte->size) {
814                         struct wim_lookup_table_entry *next;
815
816                         ctx->cur_write_stream_offset -= lte->size;
817
818                         wimlib_assert(!list_is_singular(&ctx->pending_streams) &&
819                                       !list_empty(&ctx->pending_streams));
820                         next = list_entry(lte->write_streams_list.next,
821                                           struct wim_lookup_table_entry,
822                                           write_streams_list);
823                         list_move_tail(&lte->write_streams_list,
824                                        &ctx->pack_streams);
825                         lte = next;
826                         completed_stream_count++;
827                 }
828                 if (ctx->cur_write_stream_offset == lte->size) {
829                         ctx->cur_write_stream_offset = 0;
830                         list_move_tail(&lte->write_streams_list,
831                                        &ctx->pack_streams);
832                         completed_stream_count++;
833                 }
834         } else {
835                 /* Wrote chunk in non-packed mode.  It may have finished a
836                  * stream.  */
837                 if (ctx->cur_write_stream_offset == lte->size) {
838
839                         completed_stream_count++;
840
841                         list_del(&lte->write_streams_list);
842
843                         wimlib_assert(ctx->cur_write_stream_offset ==
844                                       ctx->cur_write_res_size);
845
846                         ret = end_write_resource(ctx, &lte->out_reshdr);
847                         if (ret)
848                                 return ret;
849
850                         lte->out_reshdr.flags = filter_resource_flags(lte->flags);
851                         if (ctx->compressor != NULL)
852                                 lte->out_reshdr.flags |= WIM_RESHDR_FLAG_COMPRESSED;
853
854                         if (ctx->compressor != NULL &&
855                             lte->out_reshdr.size_in_wim >= lte->out_reshdr.uncompressed_size &&
856                             !(ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PIPABLE) &&
857                             !(lte->flags & WIM_RESHDR_FLAG_PACKED_STREAMS))
858                         {
859                                 /* Stream did not compress to less than its original
860                                  * size.  If we're not writing a pipable WIM (which
861                                  * could mean the output file descriptor is
862                                  * non-seekable), and the stream isn't located in a
863                                  * resource pack (which would make reading it again
864                                  * costly), truncate the file to the start of the stream
865                                  * and write it uncompressed instead.  */
866                                 DEBUG("Stream of size %"PRIu64" did not compress to "
867                                       "less than original size; writing uncompressed.",
868                                       lte->size);
869                                 ret = write_stream_uncompressed(lte, ctx->out_fd);
870                                 if (ret)
871                                         return ret;
872                         }
873                         wimlib_assert(lte->out_reshdr.uncompressed_size == lte->size);
874
875                         ctx->cur_write_stream_offset = 0;
876                 }
877         }
878
879         do_write_streams_progress(&ctx->progress_data, lte,
880                                   completed_size, completed_stream_count,
881                                   false);
882
883         return 0;
884
885 error:
886         ERROR_WITH_ERRNO("Write error");
887         return ret;
888 }
889
890 static int
891 submit_chunk_for_compression(struct write_streams_ctx *ctx,
892                              const void *chunk, size_t size)
893 {
894         /* While we are unable to submit the chunk for compression (due to too
895          * many chunks already outstanding), retrieve and write the next
896          * compressed chunk.  */
897         while (!ctx->compressor->submit_chunk(ctx->compressor, chunk, size)) {
898                 const void *cchunk;
899                 unsigned csize;
900                 unsigned usize;
901                 bool bret;
902                 int ret;
903
904                 bret = ctx->compressor->get_chunk(ctx->compressor,
905                                                   &cchunk, &csize, &usize);
906
907                 wimlib_assert(bret);
908
909                 ret = write_chunk(ctx, cchunk, csize, usize);
910                 if (ret)
911                         return ret;
912         }
913         return 0;
914 }
915
916 /* Process the next chunk of data to be written to a WIM resource.  */
917 static int
918 write_stream_process_chunk(const void *chunk, size_t size, void *_ctx)
919 {
920         struct write_streams_ctx *ctx = _ctx;
921         int ret;
922         const u8 *chunkptr, *chunkend;
923
924         wimlib_assert(size != 0);
925
926         if (ctx->compressor == NULL) {
927                 /* Write chunk uncompressed.  */
928                  ret = write_chunk(ctx, chunk, size, size);
929                  if (ret)
930                          return ret;
931                  ctx->cur_read_stream_offset += size;
932                  return 0;
933         }
934
935         /* Submit the chunk for compression, but take into account that the
936          * @size the chunk was provided in may not correspond to the
937          * @out_chunk_size being used for compression.  */
938         chunkptr = chunk;
939         chunkend = chunkptr + size;
940         do {
941                 const u8 *resized_chunk;
942                 size_t needed_chunk_size;
943
944                 if (ctx->write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS) {
945                         needed_chunk_size = ctx->out_chunk_size;
946                 } else {
947                         u64 res_bytes_remaining;
948
949                         res_bytes_remaining = ctx->cur_read_stream_size -
950                                               ctx->cur_read_stream_offset;
951                         needed_chunk_size = min(ctx->out_chunk_size,
952                                                 ctx->chunk_buf_filled +
953                                                         res_bytes_remaining);
954                 }
955
956                 if (ctx->chunk_buf_filled == 0 &&
957                     chunkend - chunkptr >= needed_chunk_size)
958                 {
959                         /* No intermediate buffering needed.  */
960                         resized_chunk = chunkptr;
961                         chunkptr += needed_chunk_size;
962                         ctx->cur_read_stream_offset += needed_chunk_size;
963                 } else {
964                         /* Intermediate buffering needed.  */
965                         size_t bytes_consumed;
966
967                         bytes_consumed = min(chunkend - chunkptr,
968                                              needed_chunk_size - ctx->chunk_buf_filled);
969
970                         memcpy(&ctx->chunk_buf[ctx->chunk_buf_filled],
971                                chunkptr, bytes_consumed);
972
973                         chunkptr += bytes_consumed;
974                         ctx->cur_read_stream_offset += bytes_consumed;
975                         ctx->chunk_buf_filled += bytes_consumed;
976                         if (ctx->chunk_buf_filled == needed_chunk_size) {
977                                 resized_chunk = ctx->chunk_buf;
978                                 ctx->chunk_buf_filled = 0;
979                         } else {
980                                 break;
981                         }
982
983                 }
984
985                 ret = submit_chunk_for_compression(ctx, resized_chunk,
986                                                    needed_chunk_size);
987                 if (ret)
988                         return ret;
989
990         } while (chunkptr != chunkend);
991         return 0;
992 }
993
994 /* Finish processing a stream for writing.  It may not have been completely
995  * written yet, as the chunk_compressor implementation may still have chunks
996  * buffered or being compressed.  */
997 static int
998 write_stream_end_read(struct wim_lookup_table_entry *lte, int status, void *_ctx)
999 {
1000         struct write_streams_ctx *ctx = _ctx;
1001         if (status == 0)
1002                 wimlib_assert(ctx->cur_read_stream_offset == ctx->cur_read_stream_size);
1003         if (ctx->stream_was_duplicate) {
1004                 free_lookup_table_entry(lte);
1005         } else if (lte->unhashed && ctx->lookup_table != NULL) {
1006                 list_del(&lte->unhashed_list);
1007                 lookup_table_insert(ctx->lookup_table, lte);
1008                 lte->unhashed = 0;
1009         }
1010         return status;
1011 }
1012
1013 /* Compute statistics about a list of streams that will be written.
1014  *
1015  * Assumes the streams are sorted such that all streams located in each distinct
1016  * WIM (specified by WIMStruct) are together.  */
1017 static void
1018 compute_stream_list_stats(struct list_head *stream_list,
1019                           struct write_streams_ctx *ctx)
1020 {
1021         struct wim_lookup_table_entry *lte;
1022         u64 total_bytes = 0;
1023         u64 num_streams = 0;
1024         u64 total_parts = 0;
1025         WIMStruct *prev_wim_part = NULL;
1026
1027         list_for_each_entry(lte, stream_list, write_streams_list) {
1028                 num_streams++;
1029                 total_bytes += lte->size;
1030                 if (lte->resource_location == RESOURCE_IN_WIM) {
1031                         if (prev_wim_part != lte->rspec->wim) {
1032                                 prev_wim_part = lte->rspec->wim;
1033                                 total_parts++;
1034                         }
1035                 }
1036         }
1037         ctx->progress_data.progress.write_streams.total_bytes       = total_bytes;
1038         ctx->progress_data.progress.write_streams.total_streams     = num_streams;
1039         ctx->progress_data.progress.write_streams.completed_bytes   = 0;
1040         ctx->progress_data.progress.write_streams.completed_streams = 0;
1041         ctx->progress_data.progress.write_streams.compression_type  = ctx->out_ctype;
1042         ctx->progress_data.progress.write_streams.total_parts       = total_parts;
1043         ctx->progress_data.progress.write_streams.completed_parts   = 0;
1044         ctx->progress_data.next_progress = 0;
1045 }
1046
1047 /* Find streams in @stream_list that can be copied to the output WIM in raw form
1048  * rather than compressed.  Delete these streams from @stream_list and move them
1049  * to @raw_copy_streams.  Return the total uncompressed size of the streams that
1050  * need to be compressed.  */
1051 static u64
1052 find_raw_copy_streams(struct list_head *stream_list,
1053                       int write_resource_flags,
1054                       int out_ctype,
1055                       u32 out_chunk_size,
1056                       struct list_head *raw_copy_streams)
1057 {
1058         struct wim_lookup_table_entry *lte, *tmp;
1059         u64 num_bytes_to_compress = 0;
1060
1061         INIT_LIST_HEAD(raw_copy_streams);
1062
1063         /* Initialize temporary raw_copy_ok flag.  */
1064         list_for_each_entry(lte, stream_list, write_streams_list)
1065                 if (lte->resource_location == RESOURCE_IN_WIM)
1066                         lte->rspec->raw_copy_ok = 0;
1067
1068         list_for_each_entry_safe(lte, tmp, stream_list, write_streams_list) {
1069                 if (lte->resource_location == RESOURCE_IN_WIM &&
1070                     lte->rspec->raw_copy_ok)
1071                 {
1072                         list_move_tail(&lte->write_streams_list,
1073                                        raw_copy_streams);
1074                 } else if (can_raw_copy(lte, write_resource_flags,
1075                                  out_ctype, out_chunk_size))
1076                 {
1077                         lte->rspec->raw_copy_ok = 1;
1078                         list_move_tail(&lte->write_streams_list,
1079                                        raw_copy_streams);
1080                 } else {
1081                         num_bytes_to_compress += lte->size;
1082                 }
1083         }
1084
1085         return num_bytes_to_compress;
1086 }
1087
1088 /* Copy a raw compressed resource located in another WIM file to the WIM file
1089  * being written.  */
1090 static int
1091 write_raw_copy_resource(struct wim_resource_spec *in_rspec,
1092                         struct filedes *out_fd)
1093 {
1094         u64 cur_read_offset;
1095         u64 end_read_offset;
1096         u8 buf[BUFFER_SIZE];
1097         size_t bytes_to_read;
1098         int ret;
1099         struct filedes *in_fd;
1100         struct wim_lookup_table_entry *lte;
1101         u64 out_offset_in_wim;
1102
1103         DEBUG("Copying raw compressed data (size_in_wim=%"PRIu64", "
1104               "uncompressed_size=%"PRIu64")",
1105               in_rspec->size_in_wim, in_rspec->uncompressed_size);
1106
1107         /* Copy the raw data.  */
1108         cur_read_offset = in_rspec->offset_in_wim;
1109         end_read_offset = cur_read_offset + in_rspec->size_in_wim;
1110
1111         out_offset_in_wim = out_fd->offset;
1112
1113         if (in_rspec->is_pipable) {
1114                 if (cur_read_offset < sizeof(struct pwm_stream_hdr))
1115                         return WIMLIB_ERR_INVALID_PIPABLE_WIM;
1116                 cur_read_offset -= sizeof(struct pwm_stream_hdr);
1117                 out_offset_in_wim += sizeof(struct pwm_stream_hdr);
1118         }
1119         in_fd = &in_rspec->wim->in_fd;
1120         wimlib_assert(cur_read_offset != end_read_offset);
1121         do {
1122
1123                 bytes_to_read = min(sizeof(buf), end_read_offset - cur_read_offset);
1124
1125                 ret = full_pread(in_fd, buf, bytes_to_read, cur_read_offset);
1126                 if (ret)
1127                         return ret;
1128
1129                 ret = full_write(out_fd, buf, bytes_to_read);
1130                 if (ret)
1131                         return ret;
1132
1133                 cur_read_offset += bytes_to_read;
1134
1135         } while (cur_read_offset != end_read_offset);
1136
1137         list_for_each_entry(lte, &in_rspec->stream_list, rspec_node) {
1138                 if (lte->will_be_in_output_wim) {
1139                         stream_set_out_reshdr_for_reuse(lte);
1140                         if (in_rspec->flags & WIM_RESHDR_FLAG_PACKED_STREAMS)
1141                                 lte->out_res_offset_in_wim = out_offset_in_wim;
1142                         else
1143                                 lte->out_reshdr.offset_in_wim = out_offset_in_wim;
1144
1145                 }
1146         }
1147         return 0;
1148 }
1149
1150 /* Copy a list of raw compressed resources located in other WIM file(s) to the
1151  * WIM file being written.  */
1152 static int
1153 write_raw_copy_resources(struct list_head *raw_copy_streams,
1154                          struct filedes *out_fd,
1155                          struct write_streams_progress_data *progress_data)
1156 {
1157         struct wim_lookup_table_entry *lte;
1158         int ret;
1159
1160         list_for_each_entry(lte, raw_copy_streams, write_streams_list)
1161                 lte->rspec->raw_copy_ok = 1;
1162
1163         list_for_each_entry(lte, raw_copy_streams, write_streams_list) {
1164                 if (lte->rspec->raw_copy_ok) {
1165                         /* Write each packed resource only one time, no matter
1166                          * how many streams reference it.  */
1167                         ret = write_raw_copy_resource(lte->rspec, out_fd);
1168                         if (ret)
1169                                 return ret;
1170                         lte->rspec->raw_copy_ok = 0;
1171                 }
1172                 do_write_streams_progress(progress_data, lte, lte->size,
1173                                           1, false);
1174         }
1175         return 0;
1176 }
1177
1178 /* Wait for and write all chunks pending in the compressor.  */
1179 static int
1180 finish_remaining_chunks(struct write_streams_ctx *ctx)
1181 {
1182         const void *cdata;
1183         unsigned csize;
1184         unsigned usize;
1185         int ret;
1186
1187         if (ctx->compressor == NULL)
1188                 return 0;
1189
1190         if (ctx->chunk_buf_filled != 0) {
1191                 ret = submit_chunk_for_compression(ctx, ctx->chunk_buf,
1192                                                    ctx->chunk_buf_filled);
1193                 if (ret)
1194                         return ret;
1195         }
1196
1197         while (ctx->compressor->get_chunk(ctx->compressor, &cdata, &csize, &usize)) {
1198                 ret = write_chunk(ctx, cdata, csize, usize);
1199                 if (ret)
1200                         return ret;
1201         }
1202         return 0;
1203 }
1204
1205 static void
1206 remove_zero_length_streams(struct list_head *stream_list)
1207 {
1208         struct wim_lookup_table_entry *lte, *tmp;
1209
1210         list_for_each_entry_safe(lte, tmp, stream_list, write_streams_list) {
1211                 wimlib_assert(lte->will_be_in_output_wim);
1212                 if (lte->size == 0) {
1213                         list_del(&lte->write_streams_list);
1214                         lte->out_reshdr.offset_in_wim = 0;
1215                         lte->out_reshdr.size_in_wim = 0;
1216                         lte->out_reshdr.uncompressed_size = 0;
1217                         lte->out_reshdr.flags = filter_resource_flags(lte->flags);
1218                 }
1219         }
1220 }
1221
1222 /*
1223  * Write a list of streams to the output WIM file.
1224  *
1225  * @stream_list
1226  *      The list of streams to write, specified by a list of `struct
1227  *      wim_lookup_table_entry's linked by the 'write_streams_list' member.
1228  *
1229  * @out_fd
1230  *      The file descriptor, opened for writing, to which to write the streams.
1231  *
1232  * @write_resource_flags
1233  *      Flags to modify how the streams are written:
1234  *
1235  *      WRITE_RESOURCE_FLAG_RECOMPRESS:
1236  *              Force compression of all resources, even if they could otherwise
1237  *              be re-used by copying the raw data, due to being located in a WIM
1238  *              file with compatible compression parameters.
1239  *
1240  *      WRITE_RESOURCE_FLAG_PIPABLE:
1241  *              Write the resources in the wimlib-specific pipable format, and
1242  *              furthermore do so in such a way that no seeking backwards in
1243  *              @out_fd will be performed (so it may be a pipe).
1244  *
1245  *      WRITE_RESOURCE_FLAG_PACK_STREAMS:
1246  *              Pack all the streams into a single resource rather than writing
1247  *              them in separate resources.  This flag is only valid if the WIM
1248  *              version number has been, or will be, set to
1249  *              WIM_VERSION_PACKED_STREAMS.  This flag may not be combined with
1250  *              WRITE_RESOURCE_FLAG_PIPABLE.
1251  *
1252  * @out_ctype
1253  *      Compression format to use to write the output streams, specified as one
1254  *      of the WIMLIB_COMPRESSION_TYPE_* constants, excepting
1255  *      WIMLIB_COMPRESSION_TYPE_INVALID but including
1256  *      WIMLIB_COMPRESSION_TYPE_NONE.
1257  *
1258  * @out_chunk_size
1259  *      Chunk size to use to write the streams.  It must be a valid chunk size
1260  *      for the specified compression format @out_ctype, unless @out_ctype is
1261  *      WIMLIB_COMPRESSION_TYPE_NONE, in which case this parameter is ignored.
1262  *
1263  * @num_threads
1264  *      Number of threads to use to compress data.  If 0, a default number of
1265  *      threads will be chosen.  The number of threads still may be decreased
1266  *      from the specified value if insufficient memory is detected.
1267  *
1268  * @lookup_table
1269  *      If on-the-fly deduplication of unhashed streams is desired, this
1270  *      parameter must be pointer to the lookup table for the WIMStruct on whose
1271  *      behalf the streams are being written.  Otherwise, this parameter can be
1272  *      NULL.
1273  *
1274  * @filter_ctx
1275  *      If on-the-fly deduplication of unhashed streams is desired, this
1276  *      parameter can be a pointer to a context for stream filtering used to
1277  *      detect whether the duplicate stream has been hard-filtered or not.  If
1278  *      no streams are hard-filtered or no streams are unhashed, this parameter
1279  *      can be NULL.
1280  *
1281  * @progress_func
1282  *      If non-NULL, a progress function that will be called periodically with
1283  *      WIMLIB_PROGRESS_MSG_WRITE_STREAMS messages.  Note that on-the-fly
1284  *      deduplication of unhashed streams may result in the total bytes provided
1285  *      in the progress data to decrease from one message to the next.
1286  *
1287  * This function will write the streams in @stream_list to resources in
1288  * consecutive positions in the output WIM file, or to a single packed resource
1289  * if WRITE_RESOURCE_FLAG_PACK_STREAMS was specified in @write_resource_flags.
1290  * In both cases, the @out_reshdr of the `struct wim_lookup_table_entry' for
1291  * each stream written will be updated to specify its location, size, and flags
1292  * in the output WIM.  In the packed resource case,
1293  * WIM_RESHDR_FLAG_PACKED_STREAMS will be set in the @flags field of each
1294  * @out_reshdr, and furthermore @out_res_offset_in_wim and @out_res_size_in_wim
1295  * of each @out_reshdr will be set to the offset and size, respectively, in the
1296  * output WIM of the packed resource containing the corresponding stream.
1297  *
1298  * Each of the streams to write may be in any location supported by the
1299  * resource-handling code (specifically, read_stream_list()), such as the
1300  * contents of external file that has been logically added to the output WIM, or
1301  * a stream in another WIM file that has been imported, or even a stream in the
1302  * "same" WIM file of which a modified copy is being written.  In the case that
1303  * a stream is already in a WIM file and uses compatible compression parameters,
1304  * by default this function will re-use the raw data instead of decompressing
1305  * it, then recompressing it; however, with WRITE_RESOURCE_FLAG_RECOMPRESS
1306  * specified in @write_resource_flags, this is not done.
1307  *
1308  * As a further requirement, this function requires that the
1309  * @will_be_in_output_wim member be set to 1 on all streams in @stream_list as
1310  * well as any other streams not in @stream_list that will be in the output WIM
1311  * file, but set to 0 on any other streams in the output WIM's lookup table or
1312  * sharing a packed resource with a stream in @stream_list.  Still furthermore,
1313  * if on-the-fly deduplication of streams is possible, then all streams in
1314  * @stream_list must also be linked by @lookup_table_list along with any other
1315  * streams that have @will_be_in_output_wim set.
1316  *
1317  * This function handles on-the-fly deduplication of streams for which SHA1
1318  * message digests have not yet been calculated.  Such streams may or may not
1319  * need to be written.  If @lookup_table is non-NULL, then each stream in
1320  * @stream_list that has @unhashed set but not @unique_size set is checksummed
1321  * immediately before it would otherwise be read for writing in order to
1322  * determine if it is identical to another stream already being written or one
1323  * that would be filtered out of the output WIM using stream_filtered() with the
1324  * context @filter_ctx.  Each such duplicate stream will be removed from
1325  * @stream_list, its reference count transfered to the pre-existing duplicate
1326  * stream, its memory freed, and will not be written.  Alternatively, if a
1327  * stream in @stream_list is a duplicate with any stream in @lookup_table that
1328  * has not been marked for writing or would not be hard-filtered, it is freed
1329  * and the pre-existing duplicate is written instead, taking ownership of the
1330  * reference count and slot in the @lookup_table_list.
1331  *
1332  * Returns 0 if every stream was either written successfully or did not need to
1333  * be written; otherwise returns a non-zero error code.
1334  */
1335 static int
1336 write_stream_list(struct list_head *stream_list,
1337                   struct filedes *out_fd,
1338                   int write_resource_flags,
1339                   int out_ctype,
1340                   u32 out_chunk_size,
1341                   unsigned num_threads,
1342                   struct wim_lookup_table *lookup_table,
1343                   struct filter_context *filter_ctx,
1344                   wimlib_progress_func_t progress_func)
1345 {
1346         int ret;
1347         struct write_streams_ctx ctx;
1348         struct list_head raw_copy_streams;
1349
1350         wimlib_assert((write_resource_flags &
1351                        (WRITE_RESOURCE_FLAG_PACK_STREAMS |
1352                         WRITE_RESOURCE_FLAG_PIPABLE)) !=
1353                                 (WRITE_RESOURCE_FLAG_PACK_STREAMS |
1354                                  WRITE_RESOURCE_FLAG_PIPABLE));
1355
1356         remove_zero_length_streams(stream_list);
1357
1358         if (list_empty(stream_list)) {
1359                 DEBUG("No streams to write.");
1360                 return 0;
1361         }
1362
1363         memset(&ctx, 0, sizeof(ctx));
1364
1365         /* Pre-sorting the streams is required for compute_stream_list_stats().
1366          * Afterwards, read_stream_list() need not sort them again.  */
1367         ret = sort_stream_list_by_sequential_order(stream_list,
1368                                                    offsetof(struct wim_lookup_table_entry,
1369                                                             write_streams_list));
1370         if (ret)
1371                 return ret;
1372
1373         ctx.out_fd = out_fd;
1374         ctx.lookup_table = lookup_table;
1375         ctx.out_ctype = out_ctype;
1376         ctx.out_chunk_size = out_chunk_size;
1377         ctx.write_resource_flags = write_resource_flags;
1378         ctx.filter_ctx = filter_ctx;
1379
1380         if (out_ctype != WIMLIB_COMPRESSION_TYPE_NONE) {
1381                 wimlib_assert(out_chunk_size != 0);
1382                 if (out_chunk_size <= STACK_MAX) {
1383                         ctx.chunk_buf = alloca(out_chunk_size);
1384                 } else {
1385                         ctx.chunk_buf = MALLOC(out_chunk_size);
1386                         if (ctx.chunk_buf == NULL) {
1387                                 ret = WIMLIB_ERR_NOMEM;
1388                                 goto out_destroy_context;
1389                         }
1390                 }
1391         }
1392         ctx.chunk_buf_filled = 0;
1393
1394         compute_stream_list_stats(stream_list, &ctx);
1395
1396         ctx.progress_data.progress_func = progress_func;
1397
1398         ctx.num_bytes_to_compress = find_raw_copy_streams(stream_list,
1399                                                           write_resource_flags,
1400                                                           out_ctype,
1401                                                           out_chunk_size,
1402                                                           &raw_copy_streams);
1403
1404         DEBUG("Writing stream list "
1405               "(offset = %"PRIu64", write_resource_flags=0x%08x, "
1406               "out_ctype=%d, out_chunk_size=%u, num_threads=%u, "
1407               "total_bytes=%"PRIu64", num_bytes_to_compress=%"PRIu64")",
1408               out_fd->offset, write_resource_flags,
1409               out_ctype, out_chunk_size, num_threads,
1410               ctx.progress_data.progress.write_streams.total_bytes,
1411               ctx.num_bytes_to_compress);
1412
1413         if (ctx.num_bytes_to_compress == 0) {
1414                 DEBUG("No compression needed; skipping to raw copy!");
1415                 goto out_write_raw_copy_resources;
1416         }
1417
1418         /* Unless uncompressed output was required, allocate a chunk_compressor
1419          * to do compression.  There are serial and parallel implementations of
1420          * the chunk_compressor interface.  We default to parallel using the
1421          * specified number of threads, unless the upper bound on the number
1422          * bytes needing to be compressed is less than a heuristic value.  */
1423         if (out_ctype != WIMLIB_COMPRESSION_TYPE_NONE) {
1424
1425         #ifdef ENABLE_MULTITHREADED_COMPRESSION
1426                 if (ctx.num_bytes_to_compress > max(2000000, out_chunk_size)) {
1427                         ret = new_parallel_chunk_compressor(out_ctype,
1428                                                             out_chunk_size,
1429                                                             num_threads, 0,
1430                                                             &ctx.compressor);
1431                         if (ret) {
1432                                 DEBUG("Couldn't create parallel chunk compressor "
1433                                       "(status %d)", ret);
1434                         }
1435                 }
1436         #endif
1437
1438                 if (ctx.compressor == NULL) {
1439                         ret = new_serial_chunk_compressor(out_ctype, out_chunk_size,
1440                                                           &ctx.compressor);
1441                         if (ret)
1442                                 goto out_destroy_context;
1443                 }
1444         }
1445
1446         if (ctx.compressor)
1447                 ctx.progress_data.progress.write_streams.num_threads = ctx.compressor->num_threads;
1448         else
1449                 ctx.progress_data.progress.write_streams.num_threads = 1;
1450
1451         DEBUG("Actually using %u threads",
1452               ctx.progress_data.progress.write_streams.num_threads);
1453
1454         INIT_LIST_HEAD(&ctx.pending_streams);
1455         INIT_LIST_HEAD(&ctx.pack_streams);
1456
1457         if (ctx.progress_data.progress_func) {
1458                 (*ctx.progress_data.progress_func)(WIMLIB_PROGRESS_MSG_WRITE_STREAMS,
1459                                                    &ctx.progress_data.progress);
1460         }
1461
1462         if (write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS) {
1463                 ret = begin_write_resource(&ctx, ctx.num_bytes_to_compress);
1464                 if (ret)
1465                         goto out_destroy_context;
1466         }
1467
1468         /* Read the list of streams needing to be compressed, using the
1469          * specified callbacks to execute processing of the data.  */
1470
1471         struct read_stream_list_callbacks cbs = {
1472                 .begin_stream           = write_stream_begin_read,
1473                 .begin_stream_ctx       = &ctx,
1474                 .consume_chunk          = write_stream_process_chunk,
1475                 .consume_chunk_ctx      = &ctx,
1476                 .end_stream             = write_stream_end_read,
1477                 .end_stream_ctx         = &ctx,
1478         };
1479
1480         ret = read_stream_list(stream_list,
1481                                offsetof(struct wim_lookup_table_entry, write_streams_list),
1482                                &cbs,
1483                                STREAM_LIST_ALREADY_SORTED |
1484                                         VERIFY_STREAM_HASHES |
1485                                         COMPUTE_MISSING_STREAM_HASHES);
1486
1487         if (ret)
1488                 goto out_destroy_context;
1489
1490         ret = finish_remaining_chunks(&ctx);
1491         if (ret)
1492                 goto out_destroy_context;
1493
1494         if (write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS) {
1495                 struct wim_reshdr reshdr;
1496                 struct wim_lookup_table_entry *lte;
1497                 u64 offset_in_res;
1498
1499                 ret = end_write_resource(&ctx, &reshdr);
1500                 if (ret)
1501                         goto out_destroy_context;
1502
1503                 DEBUG("Ending packed resource: %lu %lu %lu.",
1504                       reshdr.offset_in_wim,
1505                       reshdr.size_in_wim,
1506                       reshdr.uncompressed_size);
1507
1508                 offset_in_res = 0;
1509                 list_for_each_entry(lte, &ctx.pack_streams, write_streams_list) {
1510                         lte->out_reshdr.size_in_wim = lte->size;
1511                         lte->out_reshdr.flags = filter_resource_flags(lte->flags);
1512                         lte->out_reshdr.flags |= WIM_RESHDR_FLAG_PACKED_STREAMS;
1513                         lte->out_reshdr.uncompressed_size = 0;
1514                         lte->out_reshdr.offset_in_wim = offset_in_res;
1515                         lte->out_res_offset_in_wim = reshdr.offset_in_wim;
1516                         lte->out_res_size_in_wim = reshdr.size_in_wim;
1517                         lte->out_res_uncompressed_size = reshdr.uncompressed_size;
1518                         offset_in_res += lte->size;
1519                 }
1520                 wimlib_assert(offset_in_res == reshdr.uncompressed_size);
1521         }
1522
1523 out_write_raw_copy_resources:
1524         /* Copy any compressed resources for which the raw data can be reused
1525          * without decompression.  */
1526         ret = write_raw_copy_resources(&raw_copy_streams, ctx.out_fd,
1527                                        &ctx.progress_data);
1528
1529 out_destroy_context:
1530         if (out_ctype != WIMLIB_COMPRESSION_TYPE_NONE && out_chunk_size > STACK_MAX)
1531                 FREE(ctx.chunk_buf);
1532         FREE(ctx.chunk_csizes);
1533         if (ctx.compressor)
1534                 ctx.compressor->destroy(ctx.compressor);
1535         DEBUG("Done (ret=%d)", ret);
1536         return ret;
1537 }
1538
1539 static int
1540 wim_write_stream_list(WIMStruct *wim,
1541                       struct list_head *stream_list,
1542                       int write_flags,
1543                       unsigned num_threads,
1544                       struct filter_context *filter_ctx,
1545                       wimlib_progress_func_t progress_func)
1546 {
1547         int out_ctype;
1548         u32 out_chunk_size;
1549         int write_resource_flags;
1550
1551         write_resource_flags = write_flags_to_resource_flags(write_flags);
1552
1553         /* wimlib v1.6.3: pack streams by default if the WIM version number is
1554          * that usually used in solid archives.  */
1555         if (wim->hdr.wim_version == WIM_VERSION_PACKED_STREAMS)
1556                 write_resource_flags |= WRITE_RESOURCE_FLAG_PACK_STREAMS;
1557
1558         if (write_resource_flags & WRITE_RESOURCE_FLAG_PACK_STREAMS) {
1559                 out_chunk_size = wim->out_pack_chunk_size;
1560                 out_ctype = wim->out_pack_compression_type;
1561         } else {
1562                 out_chunk_size = wim->out_chunk_size;
1563                 out_ctype = wim->out_compression_type;
1564         }
1565
1566         return write_stream_list(stream_list,
1567                                  &wim->out_fd,
1568                                  write_resource_flags,
1569                                  out_ctype,
1570                                  out_chunk_size,
1571                                  num_threads,
1572                                  wim->lookup_table,
1573                                  filter_ctx,
1574                                  progress_func);
1575 }
1576
1577 static int
1578 write_wim_resource(struct wim_lookup_table_entry *lte,
1579                    struct filedes *out_fd,
1580                    int out_ctype,
1581                    u32 out_chunk_size,
1582                    int write_resource_flags)
1583 {
1584         LIST_HEAD(stream_list);
1585         list_add(&lte->write_streams_list, &stream_list);
1586         lte->will_be_in_output_wim = 1;
1587         return write_stream_list(&stream_list,
1588                                  out_fd,
1589                                  write_resource_flags & ~WRITE_RESOURCE_FLAG_PACK_STREAMS,
1590                                  out_ctype,
1591                                  out_chunk_size,
1592                                  1,
1593                                  NULL,
1594                                  NULL,
1595                                  NULL);
1596 }
1597
1598 int
1599 write_wim_resource_from_buffer(const void *buf, size_t buf_size,
1600                                int reshdr_flags, struct filedes *out_fd,
1601                                int out_ctype,
1602                                u32 out_chunk_size,
1603                                struct wim_reshdr *out_reshdr,
1604                                u8 *hash,
1605                                int write_resource_flags)
1606 {
1607         int ret;
1608         struct wim_lookup_table_entry *lte;
1609
1610         /* Set up a temporary lookup table entry to provide to
1611          * write_wim_resource().  */
1612
1613         lte = new_lookup_table_entry();
1614         if (lte == NULL)
1615                 return WIMLIB_ERR_NOMEM;
1616
1617         lte->resource_location  = RESOURCE_IN_ATTACHED_BUFFER;
1618         lte->attached_buffer    = (void*)buf;
1619         lte->size               = buf_size;
1620         lte->flags              = reshdr_flags;
1621
1622         if (write_resource_flags & WRITE_RESOURCE_FLAG_PIPABLE) {
1623                 sha1_buffer(buf, buf_size, lte->hash);
1624                 lte->unhashed = 0;
1625         } else {
1626                 lte->unhashed = 1;
1627         }
1628
1629         ret = write_wim_resource(lte, out_fd, out_ctype, out_chunk_size,
1630                                  write_resource_flags);
1631         if (ret)
1632                 goto out_free_lte;
1633
1634         copy_reshdr(out_reshdr, &lte->out_reshdr);
1635
1636         if (hash)
1637                 copy_hash(hash, lte->hash);
1638         ret = 0;
1639 out_free_lte:
1640         lte->resource_location = RESOURCE_NONEXISTENT;
1641         free_lookup_table_entry(lte);
1642         return ret;
1643 }
1644
1645 struct stream_size_table {
1646         struct hlist_head *array;
1647         size_t num_entries;
1648         size_t capacity;
1649 };
1650
1651 static int
1652 init_stream_size_table(struct stream_size_table *tab, size_t capacity)
1653 {
1654         tab->array = CALLOC(capacity, sizeof(tab->array[0]));
1655         if (tab->array == NULL)
1656                 return WIMLIB_ERR_NOMEM;
1657         tab->num_entries = 0;
1658         tab->capacity = capacity;
1659         return 0;
1660 }
1661
1662 static void
1663 destroy_stream_size_table(struct stream_size_table *tab)
1664 {
1665         FREE(tab->array);
1666 }
1667
1668 static int
1669 stream_size_table_insert(struct wim_lookup_table_entry *lte, void *_tab)
1670 {
1671         struct stream_size_table *tab = _tab;
1672         size_t pos;
1673         struct wim_lookup_table_entry *same_size_lte;
1674         struct hlist_node *tmp;
1675
1676         pos = hash_u64(lte->size) % tab->capacity;
1677         lte->unique_size = 1;
1678         hlist_for_each_entry(same_size_lte, tmp, &tab->array[pos], hash_list_2) {
1679                 if (same_size_lte->size == lte->size) {
1680                         lte->unique_size = 0;
1681                         same_size_lte->unique_size = 0;
1682                         break;
1683                 }
1684         }
1685
1686         hlist_add_head(&lte->hash_list_2, &tab->array[pos]);
1687         tab->num_entries++;
1688         return 0;
1689 }
1690
1691 struct find_streams_ctx {
1692         WIMStruct *wim;
1693         int write_flags;
1694         struct list_head stream_list;
1695         struct stream_size_table stream_size_tab;
1696 };
1697
1698 static void
1699 reference_stream_for_write(struct wim_lookup_table_entry *lte,
1700                            struct list_head *stream_list, u32 nref)
1701 {
1702         if (!lte->will_be_in_output_wim) {
1703                 lte->out_refcnt = 0;
1704                 list_add_tail(&lte->write_streams_list, stream_list);
1705                 lte->will_be_in_output_wim = 1;
1706         }
1707         lte->out_refcnt += nref;
1708 }
1709
1710 static int
1711 fully_reference_stream_for_write(struct wim_lookup_table_entry *lte,
1712                                  void *_stream_list)
1713 {
1714         struct list_head *stream_list = _stream_list;
1715         lte->will_be_in_output_wim = 0;
1716         reference_stream_for_write(lte, stream_list, lte->refcnt);
1717         return 0;
1718 }
1719
1720 static int
1721 inode_find_streams_to_reference(const struct wim_inode *inode,
1722                                 const struct wim_lookup_table *table,
1723                                 struct list_head *stream_list)
1724 {
1725         struct wim_lookup_table_entry *lte;
1726         unsigned i;
1727
1728         wimlib_assert(inode->i_nlink > 0);
1729
1730         for (i = 0; i <= inode->i_num_ads; i++) {
1731                 lte = inode_stream_lte(inode, i, table);
1732                 if (lte)
1733                         reference_stream_for_write(lte, stream_list,
1734                                                    inode->i_nlink);
1735                 else if (!is_zero_hash(inode_stream_hash(inode, i)))
1736                         return WIMLIB_ERR_RESOURCE_NOT_FOUND;
1737         }
1738         return 0;
1739 }
1740
1741 static int
1742 do_stream_set_not_in_output_wim(struct wim_lookup_table_entry *lte, void *_ignore)
1743 {
1744         lte->will_be_in_output_wim = 0;
1745         return 0;
1746 }
1747
1748 static int
1749 image_find_streams_to_reference(WIMStruct *wim)
1750 {
1751         struct wim_image_metadata *imd;
1752         struct wim_inode *inode;
1753         struct wim_lookup_table_entry *lte;
1754         struct list_head *stream_list;
1755         int ret;
1756
1757         imd = wim_get_current_image_metadata(wim);
1758
1759         image_for_each_unhashed_stream(lte, imd)
1760                 lte->will_be_in_output_wim = 0;
1761
1762         stream_list = wim->private;
1763         image_for_each_inode(inode, imd) {
1764                 ret = inode_find_streams_to_reference(inode,
1765                                                       wim->lookup_table,
1766                                                       stream_list);
1767                 if (ret)
1768                         return ret;
1769         }
1770         return 0;
1771 }
1772
1773 static int
1774 prepare_unfiltered_list_of_streams_in_output_wim(WIMStruct *wim,
1775                                                  int image,
1776                                                  int streams_ok,
1777                                                  struct list_head *stream_list_ret)
1778 {
1779         int ret;
1780
1781         INIT_LIST_HEAD(stream_list_ret);
1782
1783         if (streams_ok && (image == WIMLIB_ALL_IMAGES ||
1784                            (image == 1 && wim->hdr.image_count == 1)))
1785         {
1786                 /* Fast case:  Assume that all streams are being written and
1787                  * that the reference counts are correct.  */
1788                 struct wim_lookup_table_entry *lte;
1789                 struct wim_image_metadata *imd;
1790                 unsigned i;
1791
1792                 for_lookup_table_entry(wim->lookup_table,
1793                                        fully_reference_stream_for_write,
1794                                        stream_list_ret);
1795
1796                 for (i = 0; i < wim->hdr.image_count; i++) {
1797                         imd = wim->image_metadata[i];
1798                         image_for_each_unhashed_stream(lte, imd)
1799                                 fully_reference_stream_for_write(lte, stream_list_ret);
1800                 }
1801         } else {
1802                 /* Slow case:  Walk through the images being written and
1803                  * determine the streams referenced.  */
1804                 for_lookup_table_entry(wim->lookup_table,
1805                                        do_stream_set_not_in_output_wim, NULL);
1806                 wim->private = stream_list_ret;
1807                 ret = for_image(wim, image, image_find_streams_to_reference);
1808                 if (ret)
1809                         return ret;
1810         }
1811
1812         return 0;
1813 }
1814
1815 struct insert_other_if_hard_filtered_ctx {
1816         struct stream_size_table *tab;
1817         struct filter_context *filter_ctx;
1818 };
1819
1820 static int
1821 insert_other_if_hard_filtered(struct wim_lookup_table_entry *lte, void *_ctx)
1822 {
1823         struct insert_other_if_hard_filtered_ctx *ctx = _ctx;
1824
1825         if (!lte->will_be_in_output_wim &&
1826             stream_hard_filtered(lte, ctx->filter_ctx))
1827                 stream_size_table_insert(lte, ctx->tab);
1828         return 0;
1829 }
1830
1831 static int
1832 determine_stream_size_uniquity(struct list_head *stream_list,
1833                                struct wim_lookup_table *lt,
1834                                struct filter_context *filter_ctx)
1835 {
1836         int ret;
1837         struct stream_size_table tab;
1838         struct wim_lookup_table_entry *lte;
1839
1840         ret = init_stream_size_table(&tab, 9001);
1841         if (ret)
1842                 return ret;
1843
1844         if (may_hard_filter_streams(filter_ctx)) {
1845                 struct insert_other_if_hard_filtered_ctx ctx = {
1846                         .tab = &tab,
1847                         .filter_ctx = filter_ctx,
1848                 };
1849                 for_lookup_table_entry(lt, insert_other_if_hard_filtered, &ctx);
1850         }
1851
1852         list_for_each_entry(lte, stream_list, write_streams_list)
1853                 stream_size_table_insert(lte, &tab);
1854
1855         destroy_stream_size_table(&tab);
1856         return 0;
1857 }
1858
1859 static void
1860 filter_stream_list_for_write(struct list_head *stream_list,
1861                              struct filter_context *filter_ctx)
1862 {
1863         struct wim_lookup_table_entry *lte, *tmp;
1864
1865         list_for_each_entry_safe(lte, tmp,
1866                                  stream_list, write_streams_list)
1867         {
1868                 int status = stream_filtered(lte, filter_ctx);
1869
1870                 if (status == 0) {
1871                         /* Not filtered.  */
1872                         continue;
1873                 } else {
1874                         if (status > 0) {
1875                                 /* Soft filtered.  */
1876                         } else {
1877                                 /* Hard filtered.  */
1878                                 lte->will_be_in_output_wim = 0;
1879                                 list_del(&lte->lookup_table_list);
1880                         }
1881                         list_del(&lte->write_streams_list);
1882                 }
1883         }
1884 }
1885
1886 /*
1887  * prepare_stream_list_for_write() -
1888  *
1889  * Prepare the list of streams to write for writing a WIM containing the
1890  * specified image(s) with the specified write flags.
1891  *
1892  * @wim
1893  *      The WIMStruct on whose behalf the write is occurring.
1894  *
1895  * @image
1896  *      Image(s) from the WIM to write; may be WIMLIB_ALL_IMAGES.
1897  *
1898  * @write_flags
1899  *      WIMLIB_WRITE_FLAG_* flags for the write operation:
1900  *
1901  *      STREAMS_OK:  For writes of all images, assume that all streams in the
1902  *      lookup table of @wim and the per-image lists of unhashed streams should
1903  *      be taken as-is, and image metadata should not be searched for
1904  *      references.  This does not exclude filtering with OVERWRITE and
1905  *      SKIP_EXTERNAL_WIMS, below.
1906  *
1907  *      OVERWRITE:  Streams already present in @wim shall not be returned in
1908  *      @stream_list_ret.
1909  *
1910  *      SKIP_EXTERNAL_WIMS:  Streams already present in a WIM file, but not
1911  *      @wim, shall be be returned in neither @stream_list_ret nor
1912  *      @lookup_table_list_ret.
1913  *
1914  * @stream_list_ret
1915  *      List of streams, linked by write_streams_list, that need to be written
1916  *      will be returned here.
1917  *
1918  *      Note that this function assumes that unhashed streams will be written;
1919  *      it does not take into account that they may become duplicates when
1920  *      actually hashed.
1921  *
1922  * @lookup_table_list_ret
1923  *      List of streams, linked by lookup_table_list, that need to be included
1924  *      in the WIM's lookup table will be returned here.  This will be a
1925  *      superset of the streams in @stream_list_ret.
1926  *
1927  *      This list will be a proper superset of @stream_list_ret if and only if
1928  *      WIMLIB_WRITE_FLAG_OVERWRITE was specified in @write_flags and some of
1929  *      the streams that would otherwise need to be written were already located
1930  *      in the WIM file.
1931  *
1932  *      All streams in this list will have @out_refcnt set to the number of
1933  *      references to the stream in the output WIM.  If
1934  *      WIMLIB_WRITE_FLAG_STREAMS_OK was specified in @write_flags, @out_refcnt
1935  *      may be as low as 0.
1936  *
1937  * @filter_ctx_ret
1938  *      A context for queries of stream filter status with stream_filtered() is
1939  *      returned in this location.
1940  *
1941  * In addition, @will_be_in_output_wim will be set to 1 in all stream entries
1942  * inserted into @lookup_table_list_ret and to 0 in all stream entries in the
1943  * lookup table of @wim not inserted into @lookup_table_list_ret.
1944  *
1945  * Still furthermore, @unique_size will be set to 1 on all stream entries in
1946  * @stream_list_ret that have unique size among all stream entries in
1947  * @stream_list_ret and among all stream entries in the lookup table of @wim
1948  * that are ineligible for being written due to filtering.
1949  *
1950  * Returns 0 on success; nonzero on read error, memory allocation error, or
1951  * otherwise.
1952  */
1953 static int
1954 prepare_stream_list_for_write(WIMStruct *wim, int image,
1955                               int write_flags,
1956                               struct list_head *stream_list_ret,
1957                               struct list_head *lookup_table_list_ret,
1958                               struct filter_context *filter_ctx_ret)
1959 {
1960         int ret;
1961         struct wim_lookup_table_entry *lte;
1962
1963         filter_ctx_ret->write_flags = write_flags;
1964         filter_ctx_ret->wim = wim;
1965
1966         ret = prepare_unfiltered_list_of_streams_in_output_wim(
1967                                 wim,
1968                                 image,
1969                                 write_flags & WIMLIB_WRITE_FLAG_STREAMS_OK,
1970                                 stream_list_ret);
1971         if (ret)
1972                 return ret;
1973
1974         INIT_LIST_HEAD(lookup_table_list_ret);
1975         list_for_each_entry(lte, stream_list_ret, write_streams_list)
1976                 list_add_tail(&lte->lookup_table_list, lookup_table_list_ret);
1977
1978         ret = determine_stream_size_uniquity(stream_list_ret, wim->lookup_table,
1979                                              filter_ctx_ret);
1980         if (ret)
1981                 return ret;
1982
1983         if (may_filter_streams(filter_ctx_ret))
1984                 filter_stream_list_for_write(stream_list_ret, filter_ctx_ret);
1985
1986         return 0;
1987 }
1988
1989 static int
1990 write_wim_streams(WIMStruct *wim, int image, int write_flags,
1991                   unsigned num_threads,
1992                   wimlib_progress_func_t progress_func,
1993                   struct list_head *stream_list_override,
1994                   struct list_head *lookup_table_list_ret)
1995 {
1996         int ret;
1997         struct list_head _stream_list;
1998         struct list_head *stream_list;
1999         struct wim_lookup_table_entry *lte;
2000         struct filter_context _filter_ctx;
2001         struct filter_context *filter_ctx;
2002
2003         if (stream_list_override == NULL) {
2004                 /* Normal case: prepare stream list from image(s) being written.
2005                  */
2006                 stream_list = &_stream_list;
2007                 filter_ctx = &_filter_ctx;
2008                 ret = prepare_stream_list_for_write(wim, image, write_flags,
2009                                                     stream_list,
2010                                                     lookup_table_list_ret,
2011                                                     filter_ctx);
2012                 if (ret)
2013                         return ret;
2014         } else {
2015                 /* Currently only as a result of wimlib_split() being called:
2016                  * use stream list already explicitly provided.  Use existing
2017                  * reference counts.  */
2018                 stream_list = stream_list_override;
2019                 filter_ctx = NULL;
2020                 INIT_LIST_HEAD(lookup_table_list_ret);
2021                 list_for_each_entry(lte, stream_list, write_streams_list) {
2022                         lte->out_refcnt = lte->refcnt;
2023                         lte->will_be_in_output_wim = 1;
2024                         lte->unique_size = 0;
2025                         list_add_tail(&lte->lookup_table_list, lookup_table_list_ret);
2026                 }
2027         }
2028
2029         return wim_write_stream_list(wim,
2030                                      stream_list,
2031                                      write_flags,
2032                                      num_threads,
2033                                      filter_ctx,
2034                                      progress_func);
2035 }
2036
2037 static int
2038 write_wim_metadata_resources(WIMStruct *wim, int image, int write_flags,
2039                              wimlib_progress_func_t progress_func)
2040 {
2041         int ret;
2042         int start_image;
2043         int end_image;
2044         int write_resource_flags;
2045
2046         if (write_flags & WIMLIB_WRITE_FLAG_NO_METADATA) {
2047                 DEBUG("Not writing any metadata resources.");
2048                 return 0;
2049         }
2050
2051         write_resource_flags = write_flags_to_resource_flags(write_flags);
2052
2053         write_resource_flags &= ~WRITE_RESOURCE_FLAG_PACK_STREAMS;
2054
2055         DEBUG("Writing metadata resources (offset=%"PRIu64")",
2056               wim->out_fd.offset);
2057
2058         if (progress_func)
2059                 progress_func(WIMLIB_PROGRESS_MSG_WRITE_METADATA_BEGIN, NULL);
2060
2061         if (image == WIMLIB_ALL_IMAGES) {
2062                 start_image = 1;
2063                 end_image = wim->hdr.image_count;
2064         } else {
2065                 start_image = image;
2066                 end_image = image;
2067         }
2068
2069         for (int i = start_image; i <= end_image; i++) {
2070                 struct wim_image_metadata *imd;
2071
2072                 imd = wim->image_metadata[i - 1];
2073                 /* Build a new metadata resource only if image was modified from
2074                  * the original (or was newly added).  Otherwise just copy the
2075                  * existing one.  */
2076                 if (imd->modified) {
2077                         DEBUG("Image %u was modified; building and writing new "
2078                               "metadata resource", i);
2079                         ret = write_metadata_resource(wim, i,
2080                                                       write_resource_flags);
2081                 } else if (write_flags & WIMLIB_WRITE_FLAG_OVERWRITE) {
2082                         DEBUG("Image %u was not modified; re-using existing "
2083                               "metadata resource.", i);
2084                         stream_set_out_reshdr_for_reuse(imd->metadata_lte);
2085                         ret = 0;
2086                 } else {
2087                         DEBUG("Image %u was not modified; copying existing "
2088                               "metadata resource.", i);
2089                         ret = write_wim_resource(imd->metadata_lte,
2090                                                  &wim->out_fd,
2091                                                  wim->out_compression_type,
2092                                                  wim->out_chunk_size,
2093                                                  write_resource_flags);
2094                 }
2095                 if (ret)
2096                         return ret;
2097         }
2098         if (progress_func)
2099                 progress_func(WIMLIB_PROGRESS_MSG_WRITE_METADATA_END, NULL);
2100         return 0;
2101 }
2102
2103 static int
2104 open_wim_writable(WIMStruct *wim, const tchar *path, int open_flags)
2105 {
2106         int raw_fd;
2107         DEBUG("Opening \"%"TS"\" for writing.", path);
2108
2109         raw_fd = topen(path, open_flags | O_BINARY, 0644);
2110         if (raw_fd < 0) {
2111                 ERROR_WITH_ERRNO("Failed to open \"%"TS"\" for writing", path);
2112                 return WIMLIB_ERR_OPEN;
2113         }
2114         filedes_init(&wim->out_fd, raw_fd);
2115         return 0;
2116 }
2117
2118 static int
2119 close_wim_writable(WIMStruct *wim, int write_flags)
2120 {
2121         int ret = 0;
2122
2123         if (!(write_flags & WIMLIB_WRITE_FLAG_FILE_DESCRIPTOR)) {
2124                 DEBUG("Closing WIM file.");
2125                 if (filedes_valid(&wim->out_fd))
2126                         if (filedes_close(&wim->out_fd))
2127                                 ret = WIMLIB_ERR_WRITE;
2128         }
2129         filedes_invalidate(&wim->out_fd);
2130         return ret;
2131 }
2132
2133 static int
2134 cmp_streams_by_out_rspec(const void *p1, const void *p2)
2135 {
2136         const struct wim_lookup_table_entry *lte1, *lte2;
2137
2138         lte1 = *(const struct wim_lookup_table_entry**)p1;
2139         lte2 = *(const struct wim_lookup_table_entry**)p2;
2140
2141         if (lte1->out_reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
2142                 if (lte2->out_reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
2143                         if (lte1->out_res_offset_in_wim != lte2->out_res_offset_in_wim)
2144                                 return cmp_u64(lte1->out_res_offset_in_wim,
2145                                                lte2->out_res_offset_in_wim);
2146                 } else {
2147                         return 1;
2148                 }
2149         } else {
2150                 if (lte2->out_reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS)
2151                         return -1;
2152         }
2153         return cmp_u64(lte1->out_reshdr.offset_in_wim,
2154                        lte2->out_reshdr.offset_in_wim);
2155 }
2156
2157 static int
2158 write_wim_lookup_table(WIMStruct *wim, int image, int write_flags,
2159                        struct wim_reshdr *out_reshdr,
2160                        struct list_head *lookup_table_list)
2161 {
2162         int ret;
2163
2164         /* Set output resource metadata for streams already present in WIM.  */
2165         if (write_flags & WIMLIB_WRITE_FLAG_OVERWRITE) {
2166                 struct wim_lookup_table_entry *lte;
2167                 list_for_each_entry(lte, lookup_table_list, lookup_table_list)
2168                 {
2169                         if (lte->resource_location == RESOURCE_IN_WIM &&
2170                             lte->rspec->wim == wim)
2171                         {
2172                                 stream_set_out_reshdr_for_reuse(lte);
2173                         }
2174                 }
2175         }
2176
2177         ret = sort_stream_list(lookup_table_list,
2178                                offsetof(struct wim_lookup_table_entry, lookup_table_list),
2179                                cmp_streams_by_out_rspec);
2180         if (ret)
2181                 return ret;
2182
2183         /* Add entries for metadata resources.  */
2184         if (!(write_flags & WIMLIB_WRITE_FLAG_NO_METADATA)) {
2185                 int start_image;
2186                 int end_image;
2187
2188                 if (image == WIMLIB_ALL_IMAGES) {
2189                         start_image = 1;
2190                         end_image = wim->hdr.image_count;
2191                 } else {
2192                         start_image = image;
2193                         end_image = image;
2194                 }
2195
2196                 /* Push metadata resource lookup table entries onto the front of
2197                  * the list in reverse order, so that they're written in order.
2198                  */
2199                 for (int i = end_image; i >= start_image; i--) {
2200                         struct wim_lookup_table_entry *metadata_lte;
2201
2202                         metadata_lte = wim->image_metadata[i - 1]->metadata_lte;
2203                         wimlib_assert(metadata_lte->out_reshdr.flags & WIM_RESHDR_FLAG_METADATA);
2204                         metadata_lte->out_refcnt = 1;
2205                         list_add(&metadata_lte->lookup_table_list, lookup_table_list);
2206                 }
2207         }
2208
2209         return write_wim_lookup_table_from_stream_list(lookup_table_list,
2210                                                        &wim->out_fd,
2211                                                        wim->hdr.part_number,
2212                                                        out_reshdr,
2213                                                        write_flags_to_resource_flags(write_flags));
2214 }
2215
2216 /*
2217  * finish_write():
2218  *
2219  * Finish writing a WIM file: write the lookup table, xml data, and integrity
2220  * table, then overwrite the WIM header.  By default, closes the WIM file
2221  * descriptor (@wim->out_fd) if successful.
2222  *
2223  * write_flags is a bitwise OR of the following:
2224  *
2225  *      (public) WIMLIB_WRITE_FLAG_CHECK_INTEGRITY:
2226  *              Include an integrity table.
2227  *
2228  *      (public) WIMLIB_WRITE_FLAG_FSYNC:
2229  *              fsync() the output file before closing it.
2230  *
2231  *      (public) WIMLIB_WRITE_FLAG_PIPABLE:
2232  *              Writing a pipable WIM, possibly to a pipe; include pipable WIM
2233  *              stream headers before the lookup table and XML data, and also
2234  *              write the WIM header at the end instead of seeking to the
2235  *              beginning.  Can't be combined with
2236  *              WIMLIB_WRITE_FLAG_CHECK_INTEGRITY.
2237  *
2238  *      (private) WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE:
2239  *              Don't write the lookup table.
2240  *
2241  *      (private) WIMLIB_WRITE_FLAG_REUSE_INTEGRITY_TABLE:
2242  *              When (if) writing the integrity table, re-use entries from the
2243  *              existing integrity table, if possible.
2244  *
2245  *      (private) WIMLIB_WRITE_FLAG_CHECKPOINT_AFTER_XML:
2246  *              After writing the XML data but before writing the integrity
2247  *              table, write a temporary WIM header and flush the stream so that
2248  *              the WIM is less likely to become corrupted upon abrupt program
2249  *              termination.
2250  *      (private) WIMLIB_WRITE_FLAG_HEADER_AT_END:
2251  *              Instead of overwriting the WIM header at the beginning of the
2252  *              file, simply append it to the end of the file.  (Used when
2253  *              writing to pipe.)
2254  *      (private) WIMLIB_WRITE_FLAG_FILE_DESCRIPTOR:
2255  *              Do not close the file descriptor @wim->out_fd on either success
2256  *              on failure.
2257  *      (private) WIMLIB_WRITE_FLAG_USE_EXISTING_TOTALBYTES:
2258  *              Use the existing <TOTALBYTES> stored in the in-memory XML
2259  *              information, rather than setting it to the offset of the XML
2260  *              data being written.
2261  */
2262 static int
2263 finish_write(WIMStruct *wim, int image, int write_flags,
2264              wimlib_progress_func_t progress_func,
2265              struct list_head *lookup_table_list)
2266 {
2267         int ret;
2268         off_t hdr_offset;
2269         int write_resource_flags;
2270         off_t old_lookup_table_end;
2271         off_t new_lookup_table_end;
2272         u64 xml_totalbytes;
2273
2274         DEBUG("image=%d, write_flags=%08x", image, write_flags);
2275
2276         write_resource_flags = write_flags_to_resource_flags(write_flags);
2277
2278         /* In the WIM header, there is room for the resource entry for a
2279          * metadata resource labeled as the "boot metadata".  This entry should
2280          * be zeroed out if there is no bootable image (boot_idx 0).  Otherwise,
2281          * it should be a copy of the resource entry for the image that is
2282          * marked as bootable.  This is not well documented...  */
2283         if (wim->hdr.boot_idx == 0) {
2284                 zero_reshdr(&wim->hdr.boot_metadata_reshdr);
2285         } else {
2286                 copy_reshdr(&wim->hdr.boot_metadata_reshdr,
2287                             &wim->image_metadata[
2288                                 wim->hdr.boot_idx - 1]->metadata_lte->out_reshdr);
2289         }
2290
2291         /* Write lookup table.  (Save old position first.)  */
2292         old_lookup_table_end = wim->hdr.lookup_table_reshdr.offset_in_wim +
2293                                wim->hdr.lookup_table_reshdr.size_in_wim;
2294         if (!(write_flags & WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE)) {
2295                 ret = write_wim_lookup_table(wim, image, write_flags,
2296                                              &wim->hdr.lookup_table_reshdr,
2297                                              lookup_table_list);
2298                 if (ret)
2299                         return ret;
2300         }
2301
2302         /* Write XML data.  */
2303         xml_totalbytes = wim->out_fd.offset;
2304         if (write_flags & WIMLIB_WRITE_FLAG_USE_EXISTING_TOTALBYTES)
2305                 xml_totalbytes = WIM_TOTALBYTES_USE_EXISTING;
2306         ret = write_wim_xml_data(wim, image, xml_totalbytes,
2307                                  &wim->hdr.xml_data_reshdr,
2308                                  write_resource_flags);
2309         if (ret)
2310                 return ret;
2311
2312         /* Write integrity table (optional).  */
2313         if (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY) {
2314                 if (write_flags & WIMLIB_WRITE_FLAG_CHECKPOINT_AFTER_XML) {
2315                         struct wim_header checkpoint_hdr;
2316                         memcpy(&checkpoint_hdr, &wim->hdr, sizeof(struct wim_header));
2317                         zero_reshdr(&checkpoint_hdr.integrity_table_reshdr);
2318                         checkpoint_hdr.flags |= WIM_HDR_FLAG_WRITE_IN_PROGRESS;
2319                         ret = write_wim_header_at_offset(&checkpoint_hdr,
2320                                                          &wim->out_fd, 0);
2321                         if (ret)
2322                                 return ret;
2323                 }
2324
2325                 if (!(write_flags & WIMLIB_WRITE_FLAG_REUSE_INTEGRITY_TABLE))
2326                         old_lookup_table_end = 0;
2327
2328                 new_lookup_table_end = wim->hdr.lookup_table_reshdr.offset_in_wim +
2329                                        wim->hdr.lookup_table_reshdr.size_in_wim;
2330
2331                 ret = write_integrity_table(wim,
2332                                             new_lookup_table_end,
2333                                             old_lookup_table_end,
2334                                             progress_func);
2335                 if (ret)
2336                         return ret;
2337         } else {
2338                 /* No integrity table.  */
2339                 zero_reshdr(&wim->hdr.integrity_table_reshdr);
2340         }
2341
2342         /* Now that all information in the WIM header has been determined, the
2343          * preliminary header written earlier can be overwritten, the header of
2344          * the existing WIM file can be overwritten, or the final header can be
2345          * written to the end of the pipable WIM.  */
2346         wim->hdr.flags &= ~WIM_HDR_FLAG_WRITE_IN_PROGRESS;
2347         hdr_offset = 0;
2348         if (write_flags & WIMLIB_WRITE_FLAG_HEADER_AT_END)
2349                 hdr_offset = wim->out_fd.offset;
2350         DEBUG("Writing new header @ %"PRIu64".", hdr_offset);
2351         ret = write_wim_header_at_offset(&wim->hdr, &wim->out_fd, hdr_offset);
2352         if (ret)
2353                 return ret;
2354
2355         /* Possibly sync file data to disk before closing.  On POSIX systems, it
2356          * is necessary to do this before using rename() to overwrite an
2357          * existing file with a new file.  Otherwise, data loss would occur if
2358          * the system is abruptly terminated when the metadata for the rename
2359          * operation has been written to disk, but the new file data has not.
2360          */
2361         if (write_flags & WIMLIB_WRITE_FLAG_FSYNC) {
2362                 DEBUG("Syncing WIM file.");
2363                 if (fsync(wim->out_fd.fd)) {
2364                         ERROR_WITH_ERRNO("Error syncing data to WIM file");
2365                         return WIMLIB_ERR_WRITE;
2366                 }
2367         }
2368
2369         if (close_wim_writable(wim, write_flags)) {
2370                 ERROR_WITH_ERRNO("Failed to close the output WIM file");
2371                 return WIMLIB_ERR_WRITE;
2372         }
2373
2374         return 0;
2375 }
2376
2377 #if defined(HAVE_SYS_FILE_H) && defined(HAVE_FLOCK)
2378 int
2379 lock_wim(WIMStruct *wim, int fd)
2380 {
2381         int ret = 0;
2382         if (fd != -1 && !wim->wim_locked) {
2383                 ret = flock(fd, LOCK_EX | LOCK_NB);
2384                 if (ret != 0) {
2385                         if (errno == EWOULDBLOCK) {
2386                                 ERROR("`%"TS"' is already being modified or has been "
2387                                       "mounted read-write\n"
2388                                       "        by another process!", wim->filename);
2389                                 ret = WIMLIB_ERR_ALREADY_LOCKED;
2390                         } else {
2391                                 WARNING_WITH_ERRNO("Failed to lock `%"TS"'",
2392                                                    wim->filename);
2393                                 ret = 0;
2394                         }
2395                 } else {
2396                         wim->wim_locked = 1;
2397                 }
2398         }
2399         return ret;
2400 }
2401 #endif
2402
2403 /*
2404  * write_pipable_wim():
2405  *
2406  * Perform the intermediate stages of creating a "pipable" WIM (i.e. a WIM
2407  * capable of being applied from a pipe).
2408  *
2409  * Pipable WIMs are a wimlib-specific modification of the WIM format such that
2410  * images can be applied from them sequentially when the file data is sent over
2411  * a pipe.  In addition, a pipable WIM can be written sequentially to a pipe.
2412  * The modifications made to the WIM format for pipable WIMs are:
2413  *
2414  * - Magic characters in header are "WLPWM\0\0\0" (wimlib pipable WIM) instead
2415  *   of "MSWIM\0\0\0".  This lets wimlib know that the WIM is pipable and also
2416  *   stops other software from trying to read the file as a normal WIM.
2417  *
2418  * - The header at the beginning of the file does not contain all the normal
2419  *   information; in particular it will have all 0's for the lookup table and
2420  *   XML data resource entries.  This is because this information cannot be
2421  *   determined until the lookup table and XML data have been written.
2422  *   Consequently, wimlib will write the full header at the very end of the
2423  *   file.  The header at the end, however, is only used when reading the WIM
2424  *   from a seekable file (not a pipe).
2425  *
2426  * - An extra copy of the XML data is placed directly after the header.  This
2427  *   allows image names and sizes to be determined at an appropriate time when
2428  *   reading the WIM from a pipe.  This copy of the XML data is ignored if the
2429  *   WIM is read from a seekable file (not a pipe).
2430  *
2431  * - The format of resources, or streams, has been modified to allow them to be
2432  *   used before the "lookup table" has been read.  Each stream is prefixed with
2433  *   a `struct pwm_stream_hdr' that is basically an abbreviated form of `struct
2434  *   wim_lookup_table_entry_disk' that only contains the SHA1 message digest,
2435  *   uncompressed stream size, and flags that indicate whether the stream is
2436  *   compressed.  The data of uncompressed streams then follows literally, while
2437  *   the data of compressed streams follows in a modified format.  Compressed
2438  *   streams do not begin with a chunk table, since the chunk table cannot be
2439  *   written until all chunks have been compressed.  Instead, each compressed
2440  *   chunk is prefixed by a `struct pwm_chunk_hdr' that gives its size.
2441  *   Furthermore, the chunk table is written at the end of the resource instead
2442  *   of the start.  Note: chunk offsets are given in the chunk table as if the
2443  *   `struct pwm_chunk_hdr's were not present; also, the chunk table is only
2444  *   used if the WIM is being read from a seekable file (not a pipe).
2445  *
2446  * - Metadata resources always come before other file resources (streams).
2447  *   (This does not by itself constitute an incompatibility with normal WIMs,
2448  *   since this is valid in normal WIMs.)
2449  *
2450  * - At least up to the end of the file resources, all components must be packed
2451  *   as tightly as possible; there cannot be any "holes" in the WIM.  (This does
2452  *   not by itself consititute an incompatibility with normal WIMs, since this
2453  *   is valid in normal WIMs.)
2454  *
2455  * Note: the lookup table, XML data, and header at the end are not used when
2456  * applying from a pipe.  They exist to support functionality such as image
2457  * application and export when the WIM is *not* read from a pipe.
2458  *
2459  *   Layout of pipable WIM:
2460  *
2461  * ---------+----------+--------------------+----------------+--------------+-----------+--------+
2462  * | Header | XML data | Metadata resources | File resources | Lookup table | XML data  | Header |
2463  * ---------+----------+--------------------+----------------+--------------+-----------+--------+
2464  *
2465  *   Layout of normal WIM:
2466  *
2467  * +--------+-----------------------------+-------------------------+
2468  * | Header | File and metadata resources | Lookup table | XML data |
2469  * +--------+-----------------------------+-------------------------+
2470  *
2471  * An optional integrity table can follow the final XML data in both normal and
2472  * pipable WIMs.  However, due to implementation details, wimlib currently can
2473  * only include an integrity table in a pipable WIM when writing it to a
2474  * seekable file (not a pipe).
2475  *
2476  * Do note that since pipable WIMs are not supported by Microsoft's software,
2477  * wimlib does not create them unless explicitly requested (with
2478  * WIMLIB_WRITE_FLAG_PIPABLE) and as stated above they use different magic
2479  * characters to identify the file.
2480  */
2481 static int
2482 write_pipable_wim(WIMStruct *wim, int image, int write_flags,
2483                   unsigned num_threads, wimlib_progress_func_t progress_func,
2484                   struct list_head *stream_list_override,
2485                   struct list_head *lookup_table_list_ret)
2486 {
2487         int ret;
2488         struct wim_reshdr xml_reshdr;
2489
2490         WARNING("Creating a pipable WIM, which will "
2491                 "be incompatible\n"
2492                 "          with Microsoft's software (wimgapi/imagex/Dism).");
2493
2494         /* At this point, the header at the beginning of the file has already
2495          * been written.  */
2496
2497         /* For efficiency, when wimlib adds an image to the WIM with
2498          * wimlib_add_image(), the SHA1 message digests of files is not
2499          * calculated; instead, they are calculated while the files are being
2500          * written.  However, this does not work when writing a pipable WIM,
2501          * since when writing a stream to a pipable WIM, its SHA1 message digest
2502          * needs to be known before the stream data is written.  Therefore,
2503          * before getting much farther, we need to pre-calculate the SHA1
2504          * message digests of all streams that will be written.  */
2505         ret = wim_checksum_unhashed_streams(wim);
2506         if (ret)
2507                 return ret;
2508
2509         /* Write extra copy of the XML data.  */
2510         ret = write_wim_xml_data(wim, image, WIM_TOTALBYTES_OMIT,
2511                                  &xml_reshdr,
2512                                  WRITE_RESOURCE_FLAG_PIPABLE);
2513         if (ret)
2514                 return ret;
2515
2516         /* Write metadata resources for the image(s) being included in the
2517          * output WIM.  */
2518         ret = write_wim_metadata_resources(wim, image, write_flags,
2519                                            progress_func);
2520         if (ret)
2521                 return ret;
2522
2523         /* Write streams needed for the image(s) being included in the output
2524          * WIM, or streams needed for the split WIM part.  */
2525         return write_wim_streams(wim, image, write_flags, num_threads,
2526                                  progress_func, stream_list_override,
2527                                  lookup_table_list_ret);
2528
2529         /* The lookup table, XML data, and header at end are handled by
2530          * finish_write().  */
2531 }
2532
2533 /* Write a standalone WIM or split WIM (SWM) part to a new file or to a file
2534  * descriptor.  */
2535 int
2536 write_wim_part(WIMStruct *wim,
2537                const void *path_or_fd,
2538                int image,
2539                int write_flags,
2540                unsigned num_threads,
2541                wimlib_progress_func_t progress_func,
2542                unsigned part_number,
2543                unsigned total_parts,
2544                struct list_head *stream_list_override,
2545                const u8 *guid)
2546 {
2547         int ret;
2548         struct wim_header hdr_save;
2549         struct list_head lookup_table_list;
2550
2551         if (total_parts == 1)
2552                 DEBUG("Writing standalone WIM.");
2553         else
2554                 DEBUG("Writing split WIM part %u/%u", part_number, total_parts);
2555         if (image == WIMLIB_ALL_IMAGES)
2556                 DEBUG("Including all images.");
2557         else
2558                 DEBUG("Including image %d only.", image);
2559         if (write_flags & WIMLIB_WRITE_FLAG_FILE_DESCRIPTOR)
2560                 DEBUG("File descriptor: %d", *(const int*)path_or_fd);
2561         else
2562                 DEBUG("Path: \"%"TS"\"", (const tchar*)path_or_fd);
2563         DEBUG("Write flags: 0x%08x", write_flags);
2564
2565         if (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY)
2566                 DEBUG("\tCHECK_INTEGRITY");
2567
2568         if (write_flags & WIMLIB_WRITE_FLAG_REBUILD)
2569                 DEBUG("\tREBUILD");
2570
2571         if (write_flags & WIMLIB_WRITE_FLAG_RECOMPRESS)
2572                 DEBUG("\tRECOMPRESS");
2573
2574         if (write_flags & WIMLIB_WRITE_FLAG_FSYNC)
2575                 DEBUG("\tFSYNC");
2576
2577         if (write_flags & WIMLIB_WRITE_FLAG_SOFT_DELETE)
2578                 DEBUG("\tFSYNC");
2579
2580         if (write_flags & WIMLIB_WRITE_FLAG_IGNORE_READONLY_FLAG)
2581                 DEBUG("\tIGNORE_READONLY_FLAG");
2582
2583         if (write_flags & WIMLIB_WRITE_FLAG_PIPABLE)
2584                 DEBUG("\tPIPABLE");
2585
2586         if (write_flags & WIMLIB_WRITE_FLAG_NOT_PIPABLE)
2587                 DEBUG("\tNOT_PIPABLE");
2588
2589         if (write_flags & WIMLIB_WRITE_FLAG_PACK_STREAMS)
2590                 DEBUG("\tPACK_STREAMS");
2591
2592         if (write_flags & WIMLIB_WRITE_FLAG_FILE_DESCRIPTOR)
2593                 DEBUG("\tFILE_DESCRIPTOR");
2594
2595         if (write_flags & WIMLIB_WRITE_FLAG_NO_METADATA)
2596                 DEBUG("\tNO_METADATA");
2597
2598         if (write_flags & WIMLIB_WRITE_FLAG_USE_EXISTING_TOTALBYTES)
2599                 DEBUG("\tUSE_EXISTING_TOTALBYTES");
2600
2601         if (num_threads == 0)
2602                 DEBUG("Number of threads: autodetect");
2603         else
2604                 DEBUG("Number of threads: %u", num_threads);
2605         DEBUG("Progress function: %s", (progress_func ? "yes" : "no"));
2606         DEBUG("Stream list:       %s", (stream_list_override ? "specified" : "autodetect"));
2607         DEBUG("GUID:              %s", ((guid || wim->guid_set_explicitly) ?
2608                                         "specified" : "generate new"));
2609
2610         /* Internally, this is always called with a valid part number and total
2611          * parts.  */
2612         wimlib_assert(total_parts >= 1);
2613         wimlib_assert(part_number >= 1 && part_number <= total_parts);
2614
2615         /* A valid image (or all images) must be specified.  */
2616         if (image != WIMLIB_ALL_IMAGES &&
2617              (image < 1 || image > wim->hdr.image_count))
2618                 return WIMLIB_ERR_INVALID_IMAGE;
2619
2620         /* If we need to write metadata resources, make sure the ::WIMStruct has
2621          * the needed information attached (e.g. is not a resource-only WIM,
2622          * such as a non-first part of a split WIM).  */
2623         if (!wim_has_metadata(wim) &&
2624             !(write_flags & WIMLIB_WRITE_FLAG_NO_METADATA))
2625                 return WIMLIB_ERR_METADATA_NOT_FOUND;
2626
2627         /* Check for contradictory flags.  */
2628         if ((write_flags & (WIMLIB_WRITE_FLAG_CHECK_INTEGRITY |
2629                             WIMLIB_WRITE_FLAG_NO_CHECK_INTEGRITY))
2630                                 == (WIMLIB_WRITE_FLAG_CHECK_INTEGRITY |
2631                                     WIMLIB_WRITE_FLAG_NO_CHECK_INTEGRITY))
2632                 return WIMLIB_ERR_INVALID_PARAM;
2633
2634         if ((write_flags & (WIMLIB_WRITE_FLAG_PIPABLE |
2635                             WIMLIB_WRITE_FLAG_NOT_PIPABLE))
2636                                 == (WIMLIB_WRITE_FLAG_PIPABLE |
2637                                     WIMLIB_WRITE_FLAG_NOT_PIPABLE))
2638                 return WIMLIB_ERR_INVALID_PARAM;
2639
2640         /* Save previous header, then start initializing the new one.  */
2641         memcpy(&hdr_save, &wim->hdr, sizeof(struct wim_header));
2642
2643         /* Set default integrity, pipable, and packed stream flags.  */
2644         if (!(write_flags & (WIMLIB_WRITE_FLAG_PIPABLE |
2645                              WIMLIB_WRITE_FLAG_NOT_PIPABLE)))
2646                 if (wim_is_pipable(wim)) {
2647                         DEBUG("WIM is pipable; default to PIPABLE.");
2648                         write_flags |= WIMLIB_WRITE_FLAG_PIPABLE;
2649                 }
2650
2651         if (!(write_flags & (WIMLIB_WRITE_FLAG_CHECK_INTEGRITY |
2652                              WIMLIB_WRITE_FLAG_NO_CHECK_INTEGRITY)))
2653                 if (wim_has_integrity_table(wim)) {
2654                         DEBUG("Integrity table present; default to CHECK_INTEGRITY.");
2655                         write_flags |= WIMLIB_WRITE_FLAG_CHECK_INTEGRITY;
2656                 }
2657
2658         if ((write_flags & (WIMLIB_WRITE_FLAG_PIPABLE |
2659                             WIMLIB_WRITE_FLAG_PACK_STREAMS))
2660                                     == (WIMLIB_WRITE_FLAG_PIPABLE |
2661                                         WIMLIB_WRITE_FLAG_PACK_STREAMS))
2662         {
2663                 ERROR("Cannot specify both PIPABLE and PACK_STREAMS!");
2664                 return WIMLIB_ERR_INVALID_PARAM;
2665         }
2666
2667         /* Set appropriate magic number.  */
2668         if (write_flags & WIMLIB_WRITE_FLAG_PIPABLE)
2669                 wim->hdr.magic = PWM_MAGIC;
2670         else
2671                 wim->hdr.magic = WIM_MAGIC;
2672
2673         /* Set appropriate version number.  */
2674         if ((write_flags & WIMLIB_WRITE_FLAG_PACK_STREAMS) ||
2675             wim->out_compression_type == WIMLIB_COMPRESSION_TYPE_LZMS)
2676                 wim->hdr.wim_version = WIM_VERSION_PACKED_STREAMS;
2677         else
2678                 wim->hdr.wim_version = WIM_VERSION_DEFAULT;
2679
2680         /* Clear header flags that will be set automatically.  */
2681         wim->hdr.flags &= ~(WIM_HDR_FLAG_METADATA_ONLY          |
2682                             WIM_HDR_FLAG_RESOURCE_ONLY          |
2683                             WIM_HDR_FLAG_SPANNED                |
2684                             WIM_HDR_FLAG_WRITE_IN_PROGRESS);
2685
2686         /* Set SPANNED header flag if writing part of a split WIM.  */
2687         if (total_parts != 1)
2688                 wim->hdr.flags |= WIM_HDR_FLAG_SPANNED;
2689
2690         /* Set part number and total parts of split WIM.  This will be 1 and 1
2691          * if the WIM is standalone.  */
2692         wim->hdr.part_number = part_number;
2693         wim->hdr.total_parts = total_parts;
2694
2695         /* Set compression type if different.  */
2696         if (wim->compression_type != wim->out_compression_type) {
2697                 ret = set_wim_hdr_cflags(wim->out_compression_type, &wim->hdr);
2698                 wimlib_assert(ret == 0);
2699         }
2700
2701         /* Set chunk size if different.  */
2702         wim->hdr.chunk_size = wim->out_chunk_size;
2703
2704         /* Use GUID if specified; otherwise generate a new one.  */
2705         if (guid)
2706                 memcpy(wim->hdr.guid, guid, WIMLIB_GUID_LEN);
2707         else if (!wim->guid_set_explicitly)
2708                 randomize_byte_array(wim->hdr.guid, WIMLIB_GUID_LEN);
2709
2710         /* Clear references to resources that have not been written yet.  */
2711         zero_reshdr(&wim->hdr.lookup_table_reshdr);
2712         zero_reshdr(&wim->hdr.xml_data_reshdr);
2713         zero_reshdr(&wim->hdr.boot_metadata_reshdr);
2714         zero_reshdr(&wim->hdr.integrity_table_reshdr);
2715
2716         /* Set image count and boot index correctly for single image writes.  */
2717         if (image != WIMLIB_ALL_IMAGES) {
2718                 wim->hdr.image_count = 1;
2719                 if (wim->hdr.boot_idx == image)
2720                         wim->hdr.boot_idx = 1;
2721                 else
2722                         wim->hdr.boot_idx = 0;
2723         }
2724
2725         /* Split WIMs can't be bootable.  */
2726         if (total_parts != 1)
2727                 wim->hdr.boot_idx = 0;
2728
2729         /* Initialize output file descriptor.  */
2730         if (write_flags & WIMLIB_WRITE_FLAG_FILE_DESCRIPTOR) {
2731                 /* File descriptor was explicitly provided.  Return error if
2732                  * file descriptor is not seekable, unless writing a pipable WIM
2733                  * was requested.  */
2734                 wim->out_fd.fd = *(const int*)path_or_fd;
2735                 wim->out_fd.offset = 0;
2736                 if (!filedes_is_seekable(&wim->out_fd)) {
2737                         ret = WIMLIB_ERR_INVALID_PARAM;
2738                         if (!(write_flags & WIMLIB_WRITE_FLAG_PIPABLE))
2739                                 goto out_restore_hdr;
2740                         if (write_flags & WIMLIB_WRITE_FLAG_CHECK_INTEGRITY) {
2741                                 ERROR("Can't include integrity check when "
2742                                       "writing pipable WIM to pipe!");
2743                                 goto out_restore_hdr;
2744                         }
2745                 }
2746
2747         } else {
2748                 /* Filename of WIM to write was provided; open file descriptor
2749                  * to it.  */
2750                 ret = open_wim_writable(wim, (const tchar*)path_or_fd,
2751                                         O_TRUNC | O_CREAT | O_RDWR);
2752                 if (ret)
2753                         goto out_restore_hdr;
2754         }
2755
2756         /* Write initial header.  This is merely a "dummy" header since it
2757          * doesn't have all the information yet, so it will be overwritten later
2758          * (unless writing a pipable WIM).  */
2759         if (!(write_flags & WIMLIB_WRITE_FLAG_PIPABLE))
2760                 wim->hdr.flags |= WIM_HDR_FLAG_WRITE_IN_PROGRESS;
2761         ret = write_wim_header(&wim->hdr, &wim->out_fd);
2762         wim->hdr.flags &= ~WIM_HDR_FLAG_WRITE_IN_PROGRESS;
2763         if (ret)
2764                 goto out_restore_hdr;
2765
2766         /* Write metadata resources and streams.  */
2767         if (!(write_flags & WIMLIB_WRITE_FLAG_PIPABLE)) {
2768                 /* Default case: create a normal (non-pipable) WIM.  */
2769                 ret = write_wim_streams(wim, image, write_flags, num_threads,
2770                                         progress_func, stream_list_override,
2771                                         &lookup_table_list);
2772                 if (ret)
2773                         goto out_restore_hdr;
2774
2775                 ret = write_wim_metadata_resources(wim, image, write_flags,
2776                                                    progress_func);
2777                 if (ret)
2778                         goto out_restore_hdr;
2779         } else {
2780                 /* Non-default case: create pipable WIM.  */
2781                 ret = write_pipable_wim(wim, image, write_flags, num_threads,
2782                                         progress_func, stream_list_override,
2783                                         &lookup_table_list);
2784                 if (ret)
2785                         goto out_restore_hdr;
2786                 write_flags |= WIMLIB_WRITE_FLAG_HEADER_AT_END;
2787         }
2788
2789
2790         /* Write lookup table, XML data, and (optional) integrity table.  */
2791         ret = finish_write(wim, image, write_flags, progress_func,
2792                            &lookup_table_list);
2793 out_restore_hdr:
2794         memcpy(&wim->hdr, &hdr_save, sizeof(struct wim_header));
2795         (void)close_wim_writable(wim, write_flags);
2796         DEBUG("ret=%d", ret);
2797         return ret;
2798 }
2799
2800 /* Write a standalone WIM to a file or file descriptor.  */
2801 static int
2802 write_standalone_wim(WIMStruct *wim, const void *path_or_fd,
2803                      int image, int write_flags, unsigned num_threads,
2804                      wimlib_progress_func_t progress_func)
2805 {
2806         return write_wim_part(wim, path_or_fd, image, write_flags,
2807                               num_threads, progress_func, 1, 1, NULL, NULL);
2808 }
2809
2810 /* API function documented in wimlib.h  */
2811 WIMLIBAPI int
2812 wimlib_write(WIMStruct *wim, const tchar *path,
2813              int image, int write_flags, unsigned num_threads,
2814              wimlib_progress_func_t progress_func)
2815 {
2816         if (write_flags & ~WIMLIB_WRITE_MASK_PUBLIC)
2817                 return WIMLIB_ERR_INVALID_PARAM;
2818
2819         if (path == NULL || path[0] == T('\0'))
2820                 return WIMLIB_ERR_INVALID_PARAM;
2821
2822         return write_standalone_wim(wim, path, image, write_flags,
2823                                     num_threads, progress_func);
2824 }
2825
2826 /* API function documented in wimlib.h  */
2827 WIMLIBAPI int
2828 wimlib_write_to_fd(WIMStruct *wim, int fd,
2829                    int image, int write_flags, unsigned num_threads,
2830                    wimlib_progress_func_t progress_func)
2831 {
2832         if (write_flags & ~WIMLIB_WRITE_MASK_PUBLIC)
2833                 return WIMLIB_ERR_INVALID_PARAM;
2834
2835         if (fd < 0)
2836                 return WIMLIB_ERR_INVALID_PARAM;
2837
2838         write_flags |= WIMLIB_WRITE_FLAG_FILE_DESCRIPTOR;
2839
2840         return write_standalone_wim(wim, &fd, image, write_flags,
2841                                     num_threads, progress_func);
2842 }
2843
2844 static bool
2845 any_images_modified(WIMStruct *wim)
2846 {
2847         for (int i = 0; i < wim->hdr.image_count; i++)
2848                 if (wim->image_metadata[i]->modified)
2849                         return true;
2850         return false;
2851 }
2852
2853 static int
2854 check_resource_offset(struct wim_lookup_table_entry *lte, void *_wim)
2855 {
2856         const WIMStruct *wim = _wim;
2857         off_t end_offset = *(const off_t*)wim->private;
2858
2859         if (lte->resource_location == RESOURCE_IN_WIM && lte->rspec->wim == wim &&
2860             lte->rspec->offset_in_wim + lte->rspec->size_in_wim > end_offset)
2861                 return WIMLIB_ERR_RESOURCE_ORDER;
2862         return 0;
2863 }
2864
2865 /* Make sure no file or metadata resources are located after the XML data (or
2866  * integrity table if present)--- otherwise we can't safely overwrite the WIM in
2867  * place and we return WIMLIB_ERR_RESOURCE_ORDER.  */
2868 static int
2869 check_resource_offsets(WIMStruct *wim, off_t end_offset)
2870 {
2871         int ret;
2872         unsigned i;
2873
2874         wim->private = &end_offset;
2875         ret = for_lookup_table_entry(wim->lookup_table, check_resource_offset, wim);
2876         if (ret)
2877                 return ret;
2878
2879         for (i = 0; i < wim->hdr.image_count; i++) {
2880                 ret = check_resource_offset(wim->image_metadata[i]->metadata_lte, wim);
2881                 if (ret)
2882                         return ret;
2883         }
2884         return 0;
2885 }
2886
2887 /*
2888  * Overwrite a WIM, possibly appending streams to it.
2889  *
2890  * A WIM looks like (or is supposed to look like) the following:
2891  *
2892  *                   Header (212 bytes)
2893  *                   Streams and metadata resources (variable size)
2894  *                   Lookup table (variable size)
2895  *                   XML data (variable size)
2896  *                   Integrity table (optional) (variable size)
2897  *
2898  * If we are not adding any streams or metadata resources, the lookup table is
2899  * unchanged--- so we only need to overwrite the XML data, integrity table, and
2900  * header.  This operation is potentially unsafe if the program is abruptly
2901  * terminated while the XML data or integrity table are being overwritten, but
2902  * before the new header has been written.  To partially alleviate this problem,
2903  * a special flag (WIMLIB_WRITE_FLAG_CHECKPOINT_AFTER_XML) is passed to
2904  * finish_write() to cause a temporary WIM header to be written after the XML
2905  * data has been written.  This may prevent the WIM from becoming corrupted if
2906  * the program is terminated while the integrity table is being calculated (but
2907  * no guarantees, due to write re-ordering...).
2908  *
2909  * If we are adding new streams or images (metadata resources), the lookup table
2910  * needs to be changed, and those streams need to be written.  In this case, we
2911  * try to perform a safe update of the WIM file by writing the streams *after*
2912  * the end of the previous WIM, then writing the new lookup table, XML data, and
2913  * (optionally) integrity table following the new streams.  This will produce a
2914  * layout like the following:
2915  *
2916  *                   Header (212 bytes)
2917  *                   (OLD) Streams and metadata resources (variable size)
2918  *                   (OLD) Lookup table (variable size)
2919  *                   (OLD) XML data (variable size)
2920  *                   (OLD) Integrity table (optional) (variable size)
2921  *                   (NEW) Streams and metadata resources (variable size)
2922  *                   (NEW) Lookup table (variable size)
2923  *                   (NEW) XML data (variable size)
2924  *                   (NEW) Integrity table (optional) (variable size)
2925  *
2926  * At all points, the WIM is valid as nothing points to the new data yet.  Then,
2927  * the header is overwritten to point to the new lookup table, XML data, and
2928  * integrity table, to produce the following layout:
2929  *
2930  *                   Header (212 bytes)
2931  *                   Streams and metadata resources (variable size)
2932  *                   Nothing (variable size)
2933  *                   More Streams and metadata resources (variable size)
2934  *                   Lookup table (variable size)
2935  *                   XML data (variable size)
2936  *                   Integrity table (optional) (variable size)
2937  *
2938  * This method allows an image to be appended to a large WIM very quickly, and
2939  * is is crash-safe except in the case of write re-ordering, but the
2940  * disadvantage is that a small hole is left in the WIM where the old lookup
2941  * table, xml data, and integrity table were.  (These usually only take up a
2942  * small amount of space compared to the streams, however.)
2943  */
2944 static int
2945 overwrite_wim_inplace(WIMStruct *wim, int write_flags,
2946                       unsigned num_threads,
2947                       wimlib_progress_func_t progress_func)
2948 {
2949         int ret;
2950         off_t old_wim_end;
2951         u64 old_lookup_table_end, old_xml_begin, old_xml_end;
2952         struct wim_header hdr_save;
2953         struct list_head stream_list;
2954         struct list_head lookup_table_list;
2955         struct filter_context filter_ctx;
2956
2957         DEBUG("Overwriting `%"TS"' in-place", wim->filename);
2958
2959         /* Save original header so it can be restored in case of error  */
2960         memcpy(&hdr_save, &wim->hdr, sizeof(struct wim_header));
2961
2962         /* Set default integrity flag.  */
2963         if (!(write_flags & (WIMLIB_WRITE_FLAG_CHECK_INTEGRITY |
2964                              WIMLIB_WRITE_FLAG_NO_CHECK_INTEGRITY)))
2965                 if (wim_has_integrity_table(wim))
2966                         write_flags |= WIMLIB_WRITE_FLAG_CHECK_INTEGRITY;
2967
2968         /* Set WIM version if adding packed streams.  */
2969         if (write_flags & WIMLIB_WRITE_FLAG_PACK_STREAMS)
2970                 wim->hdr.wim_version = WIM_VERSION_PACKED_STREAMS;
2971
2972         /* Set additional flags for overwrite.  */
2973         write_flags |= WIMLIB_WRITE_FLAG_OVERWRITE |
2974                        WIMLIB_WRITE_FLAG_STREAMS_OK;
2975
2976         /* Make sure that the integrity table (if present) is after the XML
2977          * data, and that there are no stream resources, metadata resources, or
2978          * lookup tables after the XML data.  Otherwise, these data would be
2979          * overwritten. */
2980         old_xml_begin = wim->hdr.xml_data_reshdr.offset_in_wim;
2981         old_xml_end = old_xml_begin + wim->hdr.xml_data_reshdr.size_in_wim;
2982         old_lookup_table_end = wim->hdr.lookup_table_reshdr.offset_in_wim +
2983                                wim->hdr.lookup_table_reshdr.size_in_wim;
2984         if (wim->hdr.integrity_table_reshdr.offset_in_wim != 0 &&
2985             wim->hdr.integrity_table_reshdr.offset_in_wim < old_xml_end) {
2986                 WARNING("Didn't expect the integrity table to be before the XML data");
2987                 ret = WIMLIB_ERR_RESOURCE_ORDER;
2988                 goto out_restore_memory_hdr;
2989         }
2990
2991         if (old_lookup_table_end > old_xml_begin) {
2992                 WARNING("Didn't expect the lookup table to be after the XML data");
2993                 ret = WIMLIB_ERR_RESOURCE_ORDER;
2994                 goto out_restore_memory_hdr;
2995         }
2996
2997         /* Set @old_wim_end, which indicates the point beyond which we don't
2998          * allow any file and metadata resources to appear without returning
2999          * WIMLIB_ERR_RESOURCE_ORDER (due to the fact that we would otherwise
3000          * overwrite these resources). */
3001         if (!wim->deletion_occurred && !any_images_modified(wim)) {
3002                 /* If no images have been modified and no images have been
3003                  * deleted, a new lookup table does not need to be written.  We
3004                  * shall write the new XML data and optional integrity table
3005                  * immediately after the lookup table.  Note that this may
3006                  * overwrite an existing integrity table. */
3007                 DEBUG("Skipping writing lookup table "
3008                       "(no images modified or deleted)");
3009                 old_wim_end = old_lookup_table_end;
3010                 write_flags |= WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE |
3011                                WIMLIB_WRITE_FLAG_CHECKPOINT_AFTER_XML;
3012         } else if (wim->hdr.integrity_table_reshdr.offset_in_wim != 0) {
3013                 /* Old WIM has an integrity table; begin writing new streams
3014                  * after it. */
3015                 old_wim_end = wim->hdr.integrity_table_reshdr.offset_in_wim +
3016                               wim->hdr.integrity_table_reshdr.size_in_wim;
3017         } else {
3018                 /* No existing integrity table; begin writing new streams after
3019                  * the old XML data. */
3020                 old_wim_end = old_xml_end;
3021         }
3022
3023         ret = check_resource_offsets(wim, old_wim_end);
3024         if (ret)
3025                 goto out_restore_memory_hdr;
3026
3027         ret = prepare_stream_list_for_write(wim, WIMLIB_ALL_IMAGES, write_flags,
3028                                             &stream_list, &lookup_table_list,
3029                                             &filter_ctx);
3030         if (ret)
3031                 goto out_restore_memory_hdr;
3032
3033         ret = open_wim_writable(wim, wim->filename, O_RDWR);
3034         if (ret)
3035                 goto out_restore_memory_hdr;
3036
3037         ret = lock_wim(wim, wim->out_fd.fd);
3038         if (ret)
3039                 goto out_close_wim;
3040
3041         /* Set WIM_HDR_FLAG_WRITE_IN_PROGRESS flag in header. */
3042         wim->hdr.flags |= WIM_HDR_FLAG_WRITE_IN_PROGRESS;
3043         ret = write_wim_header_flags(wim->hdr.flags, &wim->out_fd);
3044         if (ret) {
3045                 ERROR_WITH_ERRNO("Error updating WIM header flags");
3046                 goto out_unlock_wim;
3047         }
3048
3049         if (filedes_seek(&wim->out_fd, old_wim_end) == -1) {
3050                 ERROR_WITH_ERRNO("Can't seek to end of WIM");
3051                 ret = WIMLIB_ERR_WRITE;
3052                 goto out_restore_physical_hdr;
3053         }
3054
3055         ret = wim_write_stream_list(wim,
3056                                     &stream_list,
3057                                     write_flags,
3058                                     num_threads,
3059                                     &filter_ctx,
3060                                     progress_func);
3061         if (ret)
3062                 goto out_truncate;
3063
3064         ret = write_wim_metadata_resources(wim, WIMLIB_ALL_IMAGES,
3065                                            write_flags, progress_func);
3066         if (ret)
3067                 goto out_truncate;
3068
3069         write_flags |= WIMLIB_WRITE_FLAG_REUSE_INTEGRITY_TABLE;
3070         ret = finish_write(wim, WIMLIB_ALL_IMAGES, write_flags,
3071                            progress_func, &lookup_table_list);
3072         if (ret)
3073                 goto out_truncate;
3074
3075         wim->wim_locked = 0;
3076         return 0;
3077
3078 out_truncate:
3079         if (!(write_flags & WIMLIB_WRITE_FLAG_NO_LOOKUP_TABLE)) {
3080                 WARNING("Truncating `%"TS"' to its original size (%"PRIu64" bytes)",
3081                         wim->filename, old_wim_end);
3082                 /* Return value of ftruncate() is ignored because this is
3083                  * already an error path.  */
3084                 (void)ftruncate(wim->out_fd.fd, old_wim_end);
3085         }
3086 out_restore_physical_hdr:
3087         (void)write_wim_header_flags(hdr_save.flags, &wim->out_fd);
3088 out_unlock_wim:
3089         wim->wim_locked = 0;
3090 out_close_wim:
3091         (void)close_wim_writable(wim, write_flags);
3092 out_restore_memory_hdr:
3093         memcpy(&wim->hdr, &hdr_save, sizeof(struct wim_header));
3094         return ret;
3095 }
3096
3097 static int
3098 overwrite_wim_via_tmpfile(WIMStruct *wim, int write_flags,
3099                           unsigned num_threads,
3100                           wimlib_progress_func_t progress_func)
3101 {
3102         size_t wim_name_len;
3103         int ret;
3104
3105         DEBUG("Overwriting `%"TS"' via a temporary file", wim->filename);
3106
3107         /* Write the WIM to a temporary file in the same directory as the
3108          * original WIM. */
3109         wim_name_len = tstrlen(wim->filename);
3110         tchar tmpfile[wim_name_len + 10];
3111         tmemcpy(tmpfile, wim->filename, wim_name_len);
3112         randomize_char_array_with_alnum(tmpfile + wim_name_len, 9);
3113         tmpfile[wim_name_len + 9] = T('\0');
3114
3115         ret = wimlib_write(wim, tmpfile, WIMLIB_ALL_IMAGES,
3116                            write_flags | WIMLIB_WRITE_FLAG_FSYNC,
3117                            num_threads, progress_func);
3118         if (ret) {
3119                 tunlink(tmpfile);
3120                 return ret;
3121         }
3122
3123         if (filedes_valid(&wim->in_fd)) {
3124                 filedes_close(&wim->in_fd);
3125                 filedes_invalidate(&wim->in_fd);
3126         }
3127
3128         /* Rename the new WIM file to the original WIM file.  Note: on Windows
3129          * this actually calls win32_rename_replacement(), not _wrename(), so
3130          * that removing the existing destination file can be handled.  */
3131         DEBUG("Renaming `%"TS"' to `%"TS"'", tmpfile, wim->filename);
3132         ret = trename(tmpfile, wim->filename);
3133         if (ret) {
3134                 ERROR_WITH_ERRNO("Failed to rename `%"TS"' to `%"TS"'",
3135                                  tmpfile, wim->filename);
3136         #ifdef __WIN32__
3137                 if (ret < 0)
3138         #endif
3139                 {
3140                         tunlink(tmpfile);
3141                 }
3142                 return WIMLIB_ERR_RENAME;
3143         }
3144
3145         if (progress_func) {
3146                 union wimlib_progress_info progress;
3147                 progress.rename.from = tmpfile;
3148                 progress.rename.to = wim->filename;
3149                 progress_func(WIMLIB_PROGRESS_MSG_RENAME, &progress);
3150         }
3151         return 0;
3152 }
3153
3154 /* Determine if the specified WIM file may be updated by appending in-place
3155  * rather than writing and replacing it with an entirely new file.  */
3156 static bool
3157 can_overwrite_wim_inplace(const WIMStruct *wim, int write_flags)
3158 {
3159         /* REBUILD flag forces full rebuild.  */
3160         if (write_flags & WIMLIB_WRITE_FLAG_REBUILD)
3161                 return false;
3162
3163         /* Deletions cause full rebuild by default.  */
3164         if (wim->deletion_occurred && !(write_flags & WIMLIB_WRITE_FLAG_SOFT_DELETE))
3165                 return false;
3166
3167         /* Pipable WIMs cannot be updated in place, nor can a non-pipable WIM be
3168          * turned into a pipable WIM in-place.  */
3169         if (wim_is_pipable(wim) || (write_flags & WIMLIB_WRITE_FLAG_PIPABLE))
3170                 return false;
3171
3172         /* The default compression type and compression chunk size selected for
3173          * the output WIM must be the same as those currently used for the WIM.
3174          */
3175         if (wim->compression_type != wim->out_compression_type)
3176                 return false;
3177         if (wim->chunk_size != wim->out_chunk_size)
3178                 return false;
3179
3180         return true;
3181 }
3182
3183 /* API function documented in wimlib.h  */
3184 WIMLIBAPI int
3185 wimlib_overwrite(WIMStruct *wim, int write_flags,
3186                  unsigned num_threads,
3187                  wimlib_progress_func_t progress_func)
3188 {
3189         int ret;
3190         u32 orig_hdr_flags;
3191
3192         if (write_flags & ~WIMLIB_WRITE_MASK_PUBLIC)
3193                 return WIMLIB_ERR_INVALID_PARAM;
3194
3195         if (!wim->filename)
3196                 return WIMLIB_ERR_NO_FILENAME;
3197
3198         orig_hdr_flags = wim->hdr.flags;
3199         if (write_flags & WIMLIB_WRITE_FLAG_IGNORE_READONLY_FLAG)
3200                 wim->hdr.flags &= ~WIM_HDR_FLAG_READONLY;
3201         ret = can_modify_wim(wim);
3202         wim->hdr.flags = orig_hdr_flags;
3203         if (ret)
3204                 return ret;
3205
3206         if (can_overwrite_wim_inplace(wim, write_flags)) {
3207                 ret = overwrite_wim_inplace(wim, write_flags, num_threads,
3208                                             progress_func);
3209                 if (ret != WIMLIB_ERR_RESOURCE_ORDER)
3210                         return ret;
3211                 WARNING("Falling back to re-building entire WIM");
3212         }
3213         return overwrite_wim_via_tmpfile(wim, write_flags, num_threads,
3214                                          progress_func);
3215 }