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Fix for CVE-2009-2906.
[Samba.git] / source3 / smbd / fileio.c
blobadf664b3960301da1713a81589b8b8e75a6f9307
1 /*
2 Unix SMB/Netbios implementation.
3 Version 1.9.
4 read/write to a files_struct
5 Copyright (C) Andrew Tridgell 1992-1998
6 Copyright (C) Jeremy Allison 2000-2002. - write cache.
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 */
21
22 #include "includes.h"
23 #include "smbd/globals.h"
24
25 static bool setup_write_cache(files_struct *, SMB_OFF_T);
26
27 /****************************************************************************
28 Read from write cache if we can.
29 ****************************************************************************/
30
31 static bool read_from_write_cache(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
32 {
33 write_cache *wcp = fsp->wcp;
34
35 if(!wcp) {
36 return False;
37 }
38
39 if( n > wcp->data_size || pos < wcp->offset || pos + n > wcp->offset + wcp->data_size) {
40 return False;
41 }
42
43 memcpy(data, wcp->data + (pos - wcp->offset), n);
44
45 DO_PROFILE_INC(writecache_read_hits);
46
47 return True;
48 }
49
50 /****************************************************************************
51 Read from a file.
52 ****************************************************************************/
53
54 ssize_t read_file(files_struct *fsp,char *data,SMB_OFF_T pos,size_t n)
55 {
56 ssize_t ret=0,readret;
57
58 /* you can't read from print files */
59 if (fsp->print_file) {
60 return -1;
61 }
62
63 /*
64 * Serve from write cache if we can.
65 */
66
67 if(read_from_write_cache(fsp, data, pos, n)) {
68 fsp->fh->pos = pos + n;
69 fsp->fh->position_information = fsp->fh->pos;
70 return n;
71 }
72
73 flush_write_cache(fsp, READ_FLUSH);
74
75 fsp->fh->pos = pos;
76
77 if (n > 0) {
78 #ifdef DMF_FIX
79 int numretries = 3;
80 tryagain:
81 readret = SMB_VFS_PREAD(fsp,data,n,pos);
82
83 if (readret == -1) {
84 if ((errno == EAGAIN) && numretries) {
85 DEBUG(3,("read_file EAGAIN retry in 10 seconds\n"));
86 (void)sleep(10);
87 --numretries;
88 goto tryagain;
89 }
90 return -1;
91 }
92 #else /* NO DMF fix. */
93 readret = SMB_VFS_PREAD(fsp,data,n,pos);
94
95 if (readret == -1) {
96 return -1;
97 }
98 #endif
99 if (readret > 0) {
100 ret += readret;
101 }
102 }
103
104 DEBUG(10,("read_file (%s): pos = %.0f, size = %lu, returned %lu\n",
105 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
106
107 fsp->fh->pos += ret;
108 fsp->fh->position_information = fsp->fh->pos;
109
110 return(ret);
111 }
112
113 /****************************************************************************
114 *Really* write to a file.
115 ****************************************************************************/
116
117 static ssize_t real_write_file(struct smb_request *req,
118 files_struct *fsp,
119 const char *data,
120 SMB_OFF_T pos,
121 size_t n)
122 {
123 ssize_t ret;
124
125 if (pos == -1) {
126 ret = vfs_write_data(req, fsp, data, n);
127 } else {
128 fsp->fh->pos = pos;
129 if (pos && lp_strict_allocate(SNUM(fsp->conn))) {
130 if (vfs_fill_sparse(fsp, pos) == -1) {
131 return -1;
132 }
133 }
134 ret = vfs_pwrite_data(req, fsp, data, n, pos);
135 }
136
137 DEBUG(10,("real_write_file (%s): pos = %.0f, size = %lu, returned %ld\n",
138 fsp->fsp_name, (double)pos, (unsigned long)n, (long)ret ));
139
140 if (ret != -1) {
141 fsp->fh->pos += ret;
142
143 /* Yes - this is correct - writes don't update this. JRA. */
144 /* Found by Samba4 tests. */
145 #if 0
146 fsp->position_information = fsp->pos;
147 #endif
148 }
149
150 return ret;
151 }
152
153 /****************************************************************************
154 File size cache change.
155 Updates size on disk but doesn't flush the cache.
156 ****************************************************************************/
157
158 static int wcp_file_size_change(files_struct *fsp)
159 {
160 int ret;
161 write_cache *wcp = fsp->wcp;
162
163 wcp->file_size = wcp->offset + wcp->data_size;
164 ret = SMB_VFS_FTRUNCATE(fsp, wcp->file_size);
165 if (ret == -1) {
166 DEBUG(0,("wcp_file_size_change (%s): ftruncate of size %.0f error %s\n",
167 fsp->fsp_name, (double)wcp->file_size, strerror(errno) ));
168 }
169 return ret;
170 }
171
172 static void update_write_time_handler(struct event_context *ctx,
173 struct timed_event *te,
174 struct timeval now,
175 void *private_data)
176 {
177 files_struct *fsp = (files_struct *)private_data;
178
179 /* Remove the timed event handler. */
180 TALLOC_FREE(fsp->update_write_time_event);
181 DEBUG(5, ("Update write time on %s\n", fsp->fsp_name));
182
183 /* change the write time if not already changed by someone else */
184 update_write_time(fsp);
185 }
186
187 /*********************************************************
188 Schedule a write time update for WRITE_TIME_UPDATE_USEC_DELAY
189 in the future.
190 *********************************************************/
191
192 void trigger_write_time_update(struct files_struct *fsp)
193 {
194 int delay;
195
196 if (fsp->write_time_forced) {
197 /* No point - "sticky" write times
198 * in effect.
199 */
200 return;
201 }
202
203 if (fsp->update_write_time_triggered) {
204 /*
205 * We only update the write time
206 * on the first write. After that
207 * no other writes affect this.
208 */
209 return;
210 }
211 fsp->update_write_time_triggered = true;
212
213 delay = lp_parm_int(SNUM(fsp->conn),
214 "smbd", "writetimeupdatedelay",
215 WRITE_TIME_UPDATE_USEC_DELAY);
216
217 /* trigger the update 2 seconds later */
218 fsp->update_write_time_on_close = true;
219 fsp->update_write_time_event =
220 event_add_timed(smbd_event_context(), NULL,
221 timeval_current_ofs(0, delay),
222 update_write_time_handler, fsp);
223 }
224
225 void trigger_write_time_update_immediate(struct files_struct *fsp)
226 {
227 if (fsp->write_time_forced) {
228 /*
229 * No point - "sticky" write times
230 * in effect.
231 */
232 return;
233 }
234
235 TALLOC_FREE(fsp->update_write_time_event);
236 DEBUG(5, ("Update write time immediate on %s\n", fsp->fsp_name));
237
238 fsp->update_write_time_triggered = true;
239
240 fsp->update_write_time_on_close = false;
241 update_write_time(fsp);
242 }
243
244 /****************************************************************************
245 Write to a file.
246 ****************************************************************************/
247
248 ssize_t write_file(struct smb_request *req,
249 files_struct *fsp,
250 const char *data,
251 SMB_OFF_T pos,
252 size_t n)
253 {
254 write_cache *wcp = fsp->wcp;
255 ssize_t total_written = 0;
256 int write_path = -1;
257
258 if (fsp->print_file) {
259 uint32 jobid;
260
261 if (!rap_to_pjobid(fsp->rap_print_jobid, NULL, &jobid)) {
262 DEBUG(3,("write_file: Unable to map RAP jobid %u to jobid.\n",
263 (unsigned int)fsp->rap_print_jobid ));
264 errno = EBADF;
265 return -1;
266 }
267
268 return print_job_write(SNUM(fsp->conn), jobid, data, pos, n);
269 }
270
271 if (!fsp->can_write) {
272 errno = EPERM;
273 return -1;
274 }
275
276 if (!fsp->modified) {
277 SMB_STRUCT_STAT st;
278 fsp->modified = True;
279
280 if (SMB_VFS_FSTAT(fsp, &st) == 0) {
281 int dosmode;
282 trigger_write_time_update(fsp);
283 dosmode = dos_mode(fsp->conn,fsp->fsp_name,&st);
284 if ((lp_store_dos_attributes(SNUM(fsp->conn)) ||
285 MAP_ARCHIVE(fsp->conn)) &&
286 !IS_DOS_ARCHIVE(dosmode)) {
287 file_set_dosmode(fsp->conn,fsp->fsp_name,
288 dosmode | aARCH,&st,
289 NULL,
290 false);
291 }
292
293 /*
294 * If this is the first write and we have an exclusive oplock then setup
295 * the write cache.
296 */
297
298 if (EXCLUSIVE_OPLOCK_TYPE(fsp->oplock_type) && !wcp) {
299 setup_write_cache(fsp, st.st_size);
300 wcp = fsp->wcp;
301 }
302 }
303 }
304
305 #ifdef WITH_PROFILE
306 DO_PROFILE_INC(writecache_total_writes);
307 if (!fsp->oplock_type) {
308 DO_PROFILE_INC(writecache_non_oplock_writes);
309 }
310 #endif
311
312 /*
313 * If this file is level II oplocked then we need
314 * to grab the shared memory lock and inform all
315 * other files with a level II lock that they need
316 * to flush their read caches. We keep the lock over
317 * the shared memory area whilst doing this.
318 */
319
320 /* This should actually be improved to span the write. */
321 contend_level2_oplocks_begin(fsp, LEVEL2_CONTEND_WRITE);
322 contend_level2_oplocks_end(fsp, LEVEL2_CONTEND_WRITE);
323
324 #ifdef WITH_PROFILE
325 if (profile_p && profile_p->writecache_total_writes % 500 == 0) {
326 DEBUG(3,("WRITECACHE: initwrites=%u abutted=%u total=%u \
327 nonop=%u allocated=%u active=%u direct=%u perfect=%u readhits=%u\n",
328 profile_p->writecache_init_writes,
329 profile_p->writecache_abutted_writes,
330 profile_p->writecache_total_writes,
331 profile_p->writecache_non_oplock_writes,
332 profile_p->writecache_allocated_write_caches,
333 profile_p->writecache_num_write_caches,
334 profile_p->writecache_direct_writes,
335 profile_p->writecache_num_perfect_writes,
336 profile_p->writecache_read_hits ));
337
338 DEBUG(3,("WRITECACHE: Flushes SEEK=%d, READ=%d, WRITE=%d, READRAW=%d, OPLOCK=%d, CLOSE=%d, SYNC=%d\n",
339 profile_p->writecache_flushed_writes[SEEK_FLUSH],
340 profile_p->writecache_flushed_writes[READ_FLUSH],
341 profile_p->writecache_flushed_writes[WRITE_FLUSH],
342 profile_p->writecache_flushed_writes[READRAW_FLUSH],
343 profile_p->writecache_flushed_writes[OPLOCK_RELEASE_FLUSH],
344 profile_p->writecache_flushed_writes[CLOSE_FLUSH],
345 profile_p->writecache_flushed_writes[SYNC_FLUSH] ));
346 }
347 #endif
348
349 if (wcp && req->unread_bytes) {
350 /* If we're using receivefile don't
351 * deal with a write cache.
352 */
353 flush_write_cache(fsp, WRITE_FLUSH);
354 delete_write_cache(fsp);
355 wcp = NULL;
356 }
357
358 if(!wcp) {
359 DO_PROFILE_INC(writecache_direct_writes);
360 total_written = real_write_file(req, fsp, data, pos, n);
361 return total_written;
362 }
363
364 DEBUG(9,("write_file (%s)(fd=%d pos=%.0f size=%u) wcp->offset=%.0f wcp->data_size=%u\n",
365 fsp->fsp_name, fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size));
366
367 fsp->fh->pos = pos + n;
368
369 /*
370 * If we have active cache and it isn't contiguous then we flush.
371 * NOTE: There is a small problem with running out of disk ....
372 */
373
374 if (wcp->data_size) {
375 bool cache_flush_needed = False;
376
377 if ((pos >= wcp->offset) && (pos <= wcp->offset + wcp->data_size)) {
378
379 /* ASCII art.... JRA.
380
381 +--------------+-----
382 | Cached data | Rest of allocated cache buffer....
383 +--------------+-----
384
385 +-------------------+
386 | Data to write |
387 +-------------------+
388
389 */
390
391 /*
392 * Start of write overlaps or abutts the existing data.
393 */
394
395 size_t data_used = MIN((wcp->alloc_size - (pos - wcp->offset)), n);
396
397 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
398
399 /*
400 * Update the current buffer size with the new data.
401 */
402
403 if(pos + data_used > wcp->offset + wcp->data_size) {
404 wcp->data_size = pos + data_used - wcp->offset;
405 }
406
407 /*
408 * Update the file size if changed.
409 */
410
411 if (wcp->offset + wcp->data_size > wcp->file_size) {
412 if (wcp_file_size_change(fsp) == -1) {
413 return -1;
414 }
415 }
416
417 /*
418 * If we used all the data then
419 * return here.
420 */
421
422 if(n == data_used) {
423 return n;
424 } else {
425 cache_flush_needed = True;
426 }
427 /*
428 * Move the start of data forward by the amount used,
429 * cut down the amount left by the same amount.
430 */
431
432 data += data_used;
433 pos += data_used;
434 n -= data_used;
435
436 DO_PROFILE_INC(writecache_abutted_writes);
437 total_written = data_used;
438
439 write_path = 1;
440
441 } else if ((pos < wcp->offset) && (pos + n > wcp->offset) &&
442 (pos + n <= wcp->offset + wcp->alloc_size)) {
443
444 /* ASCII art.... JRA.
445
446 +---------------+
447 | Cache buffer |
448 +---------------+
449
450 +-------------------+
451 | Data to write |
452 +-------------------+
453
454 */
455
456 /*
457 * End of write overlaps the existing data.
458 */
459
460 size_t data_used = pos + n - wcp->offset;
461
462 memcpy(wcp->data, data + n - data_used, data_used);
463
464 /*
465 * Update the current buffer size with the new data.
466 */
467
468 if(pos + n > wcp->offset + wcp->data_size) {
469 wcp->data_size = pos + n - wcp->offset;
470 }
471
472 /*
473 * Update the file size if changed.
474 */
475
476 if (wcp->offset + wcp->data_size > wcp->file_size) {
477 if (wcp_file_size_change(fsp) == -1) {
478 return -1;
479 }
480 }
481
482 /*
483 * We don't need to move the start of data, but we
484 * cut down the amount left by the amount used.
485 */
486
487 n -= data_used;
488
489 /*
490 * We cannot have used all the data here.
491 */
492
493 cache_flush_needed = True;
494
495 DO_PROFILE_INC(writecache_abutted_writes);
496 total_written = data_used;
497
498 write_path = 2;
499
500 } else if ( (pos >= wcp->file_size) &&
501 (wcp->offset + wcp->data_size == wcp->file_size) &&
502 (pos > wcp->offset + wcp->data_size) &&
503 (pos < wcp->offset + wcp->alloc_size) ) {
504
505 /* ASCII art.... JRA.
506
507 End of file ---->|
508
509 +---------------+---------------+
510 | Cached data | Cache buffer |
511 +---------------+---------------+
512
513 +-------------------+
514 | Data to write |
515 +-------------------+
516
517 */
518
519 /*
520 * Non-contiguous write part of which fits within
521 * the cache buffer and is extending the file
522 * and the cache contents reflect the current
523 * data up to the current end of the file.
524 */
525
526 size_t data_used;
527
528 if(pos + n <= wcp->offset + wcp->alloc_size) {
529 data_used = n;
530 } else {
531 data_used = wcp->offset + wcp->alloc_size - pos;
532 }
533
534 /*
535 * Fill in the non-continuous area with zeros.
536 */
537
538 memset(wcp->data + wcp->data_size, '\0',
539 pos - (wcp->offset + wcp->data_size) );
540
541 memcpy(wcp->data + (pos - wcp->offset), data, data_used);
542
543 /*
544 * Update the current buffer size with the new data.
545 */
546
547 if(pos + data_used > wcp->offset + wcp->data_size) {
548 wcp->data_size = pos + data_used - wcp->offset;
549 }
550
551 /*
552 * Update the file size if changed.
553 */
554
555 if (wcp->offset + wcp->data_size > wcp->file_size) {
556 if (wcp_file_size_change(fsp) == -1) {
557 return -1;
558 }
559 }
560
561 /*
562 * If we used all the data then
563 * return here.
564 */
565
566 if(n == data_used) {
567 return n;
568 } else {
569 cache_flush_needed = True;
570 }
571
572 /*
573 * Move the start of data forward by the amount used,
574 * cut down the amount left by the same amount.
575 */
576
577 data += data_used;
578 pos += data_used;
579 n -= data_used;
580
581 DO_PROFILE_INC(writecache_abutted_writes);
582 total_written = data_used;
583
584 write_path = 3;
585
586 } else if ( (pos >= wcp->file_size) &&
587 (n == 1) &&
588 (wcp->file_size == wcp->offset + wcp->data_size) &&
589 (pos < wcp->file_size + wcp->alloc_size)) {
590
591 /*
592
593 End of file ---->|
594
595 +---------------+---------------+
596 | Cached data | Cache buffer |
597 +---------------+---------------+
598
599 |<------- allocated size ---------------->|
600
601 +--------+
602 | 1 Byte |
603 +--------+
604
605 MS-Office seems to do this a lot to determine if there's enough
606 space on the filesystem to write a new file.
607
608 Change to :
609
610 End of file ---->|
611 +-----------------------+--------+
612 | Zeroed Cached data | 1 Byte |
613 +-----------------------+--------+
614 */
615
616 flush_write_cache(fsp, WRITE_FLUSH);
617 wcp->offset = wcp->file_size;
618 wcp->data_size = pos - wcp->file_size + 1;
619 memset(wcp->data, '\0', wcp->data_size);
620 memcpy(wcp->data + wcp->data_size-1, data, 1);
621
622 /*
623 * Update the file size if changed.
624 */
625
626 if (wcp->offset + wcp->data_size > wcp->file_size) {
627 if (wcp_file_size_change(fsp) == -1) {
628 return -1;
629 }
630 }
631
632 return n;
633
634 } else {
635
636 /* ASCII art..... JRA.
637
638 Case 1).
639
640 +---------------+---------------+
641 | Cached data | Cache buffer |
642 +---------------+---------------+
643
644 +-------------------+
645 | Data to write |
646 +-------------------+
647
648 Case 2).
649
650 +---------------+---------------+
651 | Cached data | Cache buffer |
652 +---------------+---------------+
653
654 +-------------------+
655 | Data to write |
656 +-------------------+
657
658 Case 3).
659
660 +---------------+---------------+
661 | Cached data | Cache buffer |
662 +---------------+---------------+
663
664 +-----------------------------------------------------+
665 | Data to write |
666 +-----------------------------------------------------+
667
668 */
669
670 /*
671 * Write is bigger than buffer, or there is no overlap on the
672 * low or high ends.
673 */
674
675 DEBUG(9,("write_file: non cacheable write : fd = %d, pos = %.0f, len = %u, current cache pos = %.0f \
676 len = %u\n",fsp->fh->fd, (double)pos, (unsigned int)n, (double)wcp->offset, (unsigned int)wcp->data_size ));
677
678 /*
679 * If write would fit in the cache, and is larger than
680 * the data already in the cache, flush the cache and
681 * preferentially copy the data new data into it. Otherwise
682 * just write the data directly.
683 */
684
685 if ( n <= wcp->alloc_size && n > wcp->data_size) {
686 cache_flush_needed = True;
687 } else {
688 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
689
690 /*
691 * If the write overlaps the entire cache, then
692 * discard the current contents of the cache.
693 * Fix from Rasmus Borup Hansen rbh@math.ku.dk.
694 */
695
696 if ((pos <= wcp->offset) &&
697 (pos + n >= wcp->offset + wcp->data_size) ) {
698 DEBUG(9,("write_file: discarding overwritten write \
699 cache: fd = %d, off=%.0f, size=%u\n", fsp->fh->fd, (double)wcp->offset, (unsigned int)wcp->data_size ));
700 wcp->data_size = 0;
701 }
702
703 DO_PROFILE_INC(writecache_direct_writes);
704 if (ret == -1) {
705 return ret;
706 }
707
708 if (pos + ret > wcp->file_size) {
709 wcp->file_size = pos + ret;
710 }
711
712 return ret;
713 }
714
715 write_path = 4;
716
717 }
718
719 if (cache_flush_needed) {
720 DEBUG(3,("WRITE_FLUSH:%d: due to noncontinuous write: fd = %d, size = %.0f, pos = %.0f, \
721 n = %u, wcp->offset=%.0f, wcp->data_size=%u\n",
722 write_path, fsp->fh->fd, (double)wcp->file_size, (double)pos, (unsigned int)n,
723 (double)wcp->offset, (unsigned int)wcp->data_size ));
724
725 flush_write_cache(fsp, WRITE_FLUSH);
726 }
727 }
728
729 /*
730 * If the write request is bigger than the cache
731 * size, write it all out.
732 */
733
734 if (n > wcp->alloc_size ) {
735 ssize_t ret = real_write_file(NULL,fsp, data, pos, n);
736 if (ret == -1) {
737 return -1;
738 }
739
740 if (pos + ret > wcp->file_size) {
741 wcp->file_size = pos + n;
742 }
743
744 DO_PROFILE_INC(writecache_direct_writes);
745 return total_written + n;
746 }
747
748 /*
749 * If there's any data left, cache it.
750 */
751
752 if (n) {
753 #ifdef WITH_PROFILE
754 if (wcp->data_size) {
755 DO_PROFILE_INC(writecache_abutted_writes);
756 } else {
757 DO_PROFILE_INC(writecache_init_writes);
758 }
759 #endif
760 memcpy(wcp->data+wcp->data_size, data, n);
761 if (wcp->data_size == 0) {
762 wcp->offset = pos;
763 DO_PROFILE_INC(writecache_num_write_caches);
764 }
765 wcp->data_size += n;
766
767 /*
768 * Update the file size if changed.
769 */
770
771 if (wcp->offset + wcp->data_size > wcp->file_size) {
772 if (wcp_file_size_change(fsp) == -1) {
773 return -1;
774 }
775 }
776 DEBUG(9,("wcp->offset = %.0f wcp->data_size = %u cache return %u\n",
777 (double)wcp->offset, (unsigned int)wcp->data_size, (unsigned int)n));
778
779 total_written += n;
780 return total_written; /* .... that's a write :) */
781 }
782
783 return total_written;
784 }
785
786 /****************************************************************************
787 Delete the write cache structure.
788 ****************************************************************************/
789
790 void delete_write_cache(files_struct *fsp)
791 {
792 write_cache *wcp;
793
794 if(!fsp) {
795 return;
796 }
797
798 if(!(wcp = fsp->wcp)) {
799 return;
800 }
801
802 DO_PROFILE_DEC(writecache_allocated_write_caches);
803 allocated_write_caches--;
804
805 SMB_ASSERT(wcp->data_size == 0);
806
807 SAFE_FREE(wcp->data);
808 SAFE_FREE(fsp->wcp);
809
810 DEBUG(10,("delete_write_cache: File %s deleted write cache\n", fsp->fsp_name ));
811 }
812
813 /****************************************************************************
814 Setup the write cache structure.
815 ****************************************************************************/
816
817 static bool setup_write_cache(files_struct *fsp, SMB_OFF_T file_size)
818 {
819 ssize_t alloc_size = lp_write_cache_size(SNUM(fsp->conn));
820 write_cache *wcp;
821
822 if (allocated_write_caches >= MAX_WRITE_CACHES) {
823 return False;
824 }
825
826 if(alloc_size == 0 || fsp->wcp) {
827 return False;
828 }
829
830 if((wcp = SMB_MALLOC_P(write_cache)) == NULL) {
831 DEBUG(0,("setup_write_cache: malloc fail.\n"));
832 return False;
833 }
834
835 wcp->file_size = file_size;
836 wcp->offset = 0;
837 wcp->alloc_size = alloc_size;
838 wcp->data_size = 0;
839 if((wcp->data = (char *)SMB_MALLOC(wcp->alloc_size)) == NULL) {
840 DEBUG(0,("setup_write_cache: malloc fail for buffer size %u.\n",
841 (unsigned int)wcp->alloc_size ));
842 SAFE_FREE(wcp);
843 return False;
844 }
845
846 memset(wcp->data, '\0', wcp->alloc_size );
847
848 fsp->wcp = wcp;
849 DO_PROFILE_INC(writecache_allocated_write_caches);
850 allocated_write_caches++;
851
852 DEBUG(10,("setup_write_cache: File %s allocated write cache size %lu\n",
853 fsp->fsp_name, (unsigned long)wcp->alloc_size ));
854
855 return True;
856 }
857
858 /****************************************************************************
859 Cope with a size change.
860 ****************************************************************************/
861
862 void set_filelen_write_cache(files_struct *fsp, SMB_OFF_T file_size)
863 {
864 if(fsp->wcp) {
865 /* The cache *must* have been flushed before we do this. */
866 if (fsp->wcp->data_size != 0) {
867 char *msg;
868 if (asprintf(&msg, "set_filelen_write_cache: size change "
869 "on file %s with write cache size = %lu\n",
870 fsp->fsp_name,
871 (unsigned long)fsp->wcp->data_size) != -1) {
872 smb_panic(msg);
873 } else {
874 smb_panic("set_filelen_write_cache");
875 }
876 }
877 fsp->wcp->file_size = file_size;
878 }
879 }
880
881 /*******************************************************************
882 Flush a write cache struct to disk.
883 ********************************************************************/
884
885 ssize_t flush_write_cache(files_struct *fsp, enum flush_reason_enum reason)
886 {
887 write_cache *wcp = fsp->wcp;
888 size_t data_size;
889 ssize_t ret;
890
891 if(!wcp || !wcp->data_size) {
892 return 0;
893 }
894
895 data_size = wcp->data_size;
896 wcp->data_size = 0;
897
898 DO_PROFILE_DEC_INC(writecache_num_write_caches,writecache_flushed_writes[reason]);
899
900 DEBUG(9,("flushing write cache: fd = %d, off=%.0f, size=%u\n",
901 fsp->fh->fd, (double)wcp->offset, (unsigned int)data_size));
902
903 #ifdef WITH_PROFILE
904 if(data_size == wcp->alloc_size) {
905 DO_PROFILE_INC(writecache_num_perfect_writes);
906 }
907 #endif
908
909 ret = real_write_file(NULL, fsp, wcp->data, wcp->offset, data_size);
910
911 /*
912 * Ensure file size if kept up to date if write extends file.
913 */
914
915 if ((ret != -1) && (wcp->offset + ret > wcp->file_size)) {
916 wcp->file_size = wcp->offset + ret;
917 }
918
919 return ret;
920 }
921
922 /*******************************************************************
923 sync a file
924 ********************************************************************/
925
926 NTSTATUS sync_file(connection_struct *conn, files_struct *fsp, bool write_through)
927 {
928 if (fsp->fh->fd == -1)
929 return NT_STATUS_INVALID_HANDLE;
930
931 if (lp_strict_sync(SNUM(conn)) &&
932 (lp_syncalways(SNUM(conn)) || write_through)) {
933 int ret = flush_write_cache(fsp, SYNC_FLUSH);
934 if (ret == -1) {
935 return map_nt_error_from_unix(errno);
936 }
937 ret = SMB_VFS_FSYNC(fsp);
938 if (ret == -1) {
939 return map_nt_error_from_unix(errno);
940 }
941 }
942 return NT_STATUS_OK;
943 }
944
945 /************************************************************
946 Perform a stat whether a valid fd or not.
947 ************************************************************/
948
949 int fsp_stat(files_struct *fsp, SMB_STRUCT_STAT *pst)
950 {
951 if (fsp->fh->fd == -1) {
952 return SMB_VFS_STAT(fsp->conn, fsp->fsp_name, pst);
953 } else {
954 return SMB_VFS_FSTAT(fsp, pst);
955 }
956 }
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