-
Notifications
You must be signed in to change notification settings - Fork 29.1k
/
fs.c
2167 lines (1796 loc) · 54.7 KB
/
fs.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
/* Caveat emptor: this file deviates from the libuv convention of returning
* negated errno codes. Most uv_fs_*() functions map directly to the system
* call of the same name. For more complex wrappers, it's easier to just
* return -1 with errno set. The dispatcher in uv__fs_work() takes care of
* getting the errno to the right place (req->result or as the return value.)
*/
#include "uv.h"
#include "internal.h"
#include <errno.h>
#include <dlfcn.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h> /* PATH_MAX */
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/uio.h>
#include <unistd.h>
#include <fcntl.h>
#include <poll.h>
#if defined(__linux__)
# include <sys/sendfile.h>
#endif
#if defined(__sun)
# include <sys/sendfile.h>
# include <sys/sysmacros.h>
#endif
#if defined(__APPLE__)
# include <sys/sysctl.h>
#elif defined(__linux__) && !defined(FICLONE)
# include <sys/ioctl.h>
# define FICLONE _IOW(0x94, 9, int)
#endif
#if defined(_AIX) && !defined(_AIX71)
# include <utime.h>
#endif
#if defined(__APPLE__) || \
defined(__DragonFly__) || \
defined(__FreeBSD__) || \
defined(__OpenBSD__) || \
defined(__NetBSD__)
# include <sys/param.h>
# include <sys/mount.h>
#elif defined(__sun) || \
defined(__MVS__) || \
defined(__NetBSD__) || \
defined(__HAIKU__) || \
defined(__QNX__)
# include <sys/statvfs.h>
#else
# include <sys/statfs.h>
#endif
#if defined(__CYGWIN__) || \
(defined(__HAIKU__) && B_HAIKU_VERSION < B_HAIKU_VERSION_1_PRE_BETA_5) || \
(defined(__sun) && !defined(__illumos__)) || \
(defined(__APPLE__) && !TARGET_OS_IPHONE && \
MAC_OS_X_VERSION_MIN_REQUIRED < 110000)
#define preadv(fd, bufs, nbufs, off) \
pread(fd, (bufs)->iov_base, (bufs)->iov_len, off)
#define pwritev(fd, bufs, nbufs, off) \
pwrite(fd, (bufs)->iov_base, (bufs)->iov_len, off)
#endif
#if defined(_AIX) && _XOPEN_SOURCE <= 600
extern char *mkdtemp(char *template); /* See issue #740 on AIX < 7 */
#endif
#define INIT(subtype) \
do { \
if (req == NULL) \
return UV_EINVAL; \
UV_REQ_INIT(req, UV_FS); \
req->fs_type = UV_FS_ ## subtype; \
req->result = 0; \
req->ptr = NULL; \
req->loop = loop; \
req->path = NULL; \
req->new_path = NULL; \
req->bufs = NULL; \
req->cb = cb; \
} \
while (0)
#define PATH \
do { \
assert(path != NULL); \
if (cb == NULL) { \
req->path = path; \
} else { \
req->path = uv__strdup(path); \
if (req->path == NULL) \
return UV_ENOMEM; \
} \
} \
while (0)
#define PATH2 \
do { \
if (cb == NULL) { \
req->path = path; \
req->new_path = new_path; \
} else { \
size_t path_len; \
size_t new_path_len; \
path_len = strlen(path) + 1; \
new_path_len = strlen(new_path) + 1; \
req->path = uv__malloc(path_len + new_path_len); \
if (req->path == NULL) \
return UV_ENOMEM; \
req->new_path = req->path + path_len; \
memcpy((void*) req->path, path, path_len); \
memcpy((void*) req->new_path, new_path, new_path_len); \
} \
} \
while (0)
#define POST \
do { \
if (cb != NULL) { \
uv__req_register(loop, req); \
uv__work_submit(loop, \
&req->work_req, \
UV__WORK_FAST_IO, \
uv__fs_work, \
uv__fs_done); \
return 0; \
} \
else { \
uv__fs_work(&req->work_req); \
return req->result; \
} \
} \
while (0)
static int uv__fs_close(int fd) {
int rc;
rc = uv__close_nocancel(fd);
if (rc == -1)
if (errno == EINTR || errno == EINPROGRESS)
rc = 0; /* The close is in progress, not an error. */
return rc;
}
static ssize_t uv__fs_fsync(uv_fs_t* req) {
#if defined(__APPLE__)
/* Apple's fdatasync and fsync explicitly do NOT flush the drive write cache
* to the drive platters. This is in contrast to Linux's fdatasync and fsync
* which do, according to recent man pages. F_FULLFSYNC is Apple's equivalent
* for flushing buffered data to permanent storage. If F_FULLFSYNC is not
* supported by the file system we fall back to F_BARRIERFSYNC or fsync().
* This is the same approach taken by sqlite, except sqlite does not issue
* an F_BARRIERFSYNC call.
*/
int r;
r = fcntl(req->file, F_FULLFSYNC);
if (r != 0)
r = fcntl(req->file, 85 /* F_BARRIERFSYNC */); /* fsync + barrier */
if (r != 0)
r = fsync(req->file);
return r;
#else
return fsync(req->file);
#endif
}
static ssize_t uv__fs_fdatasync(uv_fs_t* req) {
#if defined(__linux__) || defined(__sun) || defined(__NetBSD__)
return fdatasync(req->file);
#elif defined(__APPLE__)
/* See the comment in uv__fs_fsync. */
return uv__fs_fsync(req);
#else
return fsync(req->file);
#endif
}
UV_UNUSED(static struct timespec uv__fs_to_timespec(double time)) {
struct timespec ts;
ts.tv_sec = time;
ts.tv_nsec = (time - ts.tv_sec) * 1e9;
/* TODO(bnoordhuis) Remove this. utimesat() has nanosecond resolution but we
* stick to microsecond resolution for the sake of consistency with other
* platforms. I'm the original author of this compatibility hack but I'm
* less convinced it's useful nowadays.
*/
ts.tv_nsec -= ts.tv_nsec % 1000;
if (ts.tv_nsec < 0) {
ts.tv_nsec += 1e9;
ts.tv_sec -= 1;
}
return ts;
}
UV_UNUSED(static struct timeval uv__fs_to_timeval(double time)) {
struct timeval tv;
tv.tv_sec = time;
tv.tv_usec = (time - tv.tv_sec) * 1e6;
if (tv.tv_usec < 0) {
tv.tv_usec += 1e6;
tv.tv_sec -= 1;
}
return tv;
}
static ssize_t uv__fs_futime(uv_fs_t* req) {
#if defined(__linux__) \
|| defined(_AIX71) \
|| defined(__HAIKU__) \
|| defined(__GNU__)
struct timespec ts[2];
ts[0] = uv__fs_to_timespec(req->atime);
ts[1] = uv__fs_to_timespec(req->mtime);
return futimens(req->file, ts);
#elif defined(__APPLE__) \
|| defined(__DragonFly__) \
|| defined(__FreeBSD__) \
|| defined(__NetBSD__) \
|| defined(__OpenBSD__) \
|| defined(__sun)
struct timeval tv[2];
tv[0] = uv__fs_to_timeval(req->atime);
tv[1] = uv__fs_to_timeval(req->mtime);
# if defined(__sun)
return futimesat(req->file, NULL, tv);
# else
return futimes(req->file, tv);
# endif
#elif defined(__MVS__)
attrib_t atr;
memset(&atr, 0, sizeof(atr));
atr.att_mtimechg = 1;
atr.att_atimechg = 1;
atr.att_mtime = req->mtime;
atr.att_atime = req->atime;
return __fchattr(req->file, &atr, sizeof(atr));
#else
errno = ENOSYS;
return -1;
#endif
}
static ssize_t uv__fs_mkdtemp(uv_fs_t* req) {
return mkdtemp((char*) req->path) ? 0 : -1;
}
static int (*uv__mkostemp)(char*, int);
static void uv__mkostemp_initonce(void) {
/* z/os doesn't have RTLD_DEFAULT but that's okay
* because it doesn't have mkostemp(O_CLOEXEC) either.
*/
#ifdef RTLD_DEFAULT
uv__mkostemp = (int (*)(char*, int)) dlsym(RTLD_DEFAULT, "mkostemp");
/* We don't care about errors, but we do want to clean them up.
* If there has been no error, then dlerror() will just return
* NULL.
*/
dlerror();
#endif /* RTLD_DEFAULT */
}
static int uv__fs_mkstemp(uv_fs_t* req) {
static uv_once_t once = UV_ONCE_INIT;
int r;
#ifdef O_CLOEXEC
static _Atomic int no_cloexec_support;
#endif
static const char pattern[] = "XXXXXX";
static const size_t pattern_size = sizeof(pattern) - 1;
char* path;
size_t path_length;
path = (char*) req->path;
path_length = strlen(path);
/* EINVAL can be returned for 2 reasons:
1. The template's last 6 characters were not XXXXXX
2. open() didn't support O_CLOEXEC
We want to avoid going to the fallback path in case
of 1, so it's manually checked before. */
if (path_length < pattern_size ||
strcmp(path + path_length - pattern_size, pattern)) {
errno = EINVAL;
r = -1;
goto clobber;
}
uv_once(&once, uv__mkostemp_initonce);
#ifdef O_CLOEXEC
if (atomic_load_explicit(&no_cloexec_support, memory_order_relaxed) == 0 &&
uv__mkostemp != NULL) {
r = uv__mkostemp(path, O_CLOEXEC);
if (r >= 0)
return r;
/* If mkostemp() returns EINVAL, it means the kernel doesn't
support O_CLOEXEC, so we just fallback to mkstemp() below. */
if (errno != EINVAL)
goto clobber;
/* We set the static variable so that next calls don't even
try to use mkostemp. */
atomic_store_explicit(&no_cloexec_support, 1, memory_order_relaxed);
}
#endif /* O_CLOEXEC */
if (req->cb != NULL)
uv_rwlock_rdlock(&req->loop->cloexec_lock);
r = mkstemp(path);
/* In case of failure `uv__cloexec` will leave error in `errno`,
* so it is enough to just set `r` to `-1`.
*/
if (r >= 0 && uv__cloexec(r, 1) != 0) {
r = uv__close(r);
if (r != 0)
abort();
r = -1;
}
if (req->cb != NULL)
uv_rwlock_rdunlock(&req->loop->cloexec_lock);
clobber:
if (r < 0)
path[0] = '\0';
return r;
}
static ssize_t uv__fs_open(uv_fs_t* req) {
#ifdef O_CLOEXEC
return open(req->path, req->flags | O_CLOEXEC, req->mode);
#else /* O_CLOEXEC */
int r;
if (req->cb != NULL)
uv_rwlock_rdlock(&req->loop->cloexec_lock);
r = open(req->path, req->flags, req->mode);
/* In case of failure `uv__cloexec` will leave error in `errno`,
* so it is enough to just set `r` to `-1`.
*/
if (r >= 0 && uv__cloexec(r, 1) != 0) {
r = uv__close(r);
if (r != 0)
abort();
r = -1;
}
if (req->cb != NULL)
uv_rwlock_rdunlock(&req->loop->cloexec_lock);
return r;
#endif /* O_CLOEXEC */
}
static ssize_t uv__fs_read(uv_fs_t* req) {
const struct iovec* bufs;
unsigned int iovmax;
size_t nbufs;
ssize_t r;
off_t off;
int fd;
fd = req->file;
off = req->off;
bufs = (const struct iovec*) req->bufs;
nbufs = req->nbufs;
iovmax = uv__getiovmax();
if (nbufs > iovmax)
nbufs = iovmax;
r = 0;
if (off < 0) {
if (nbufs == 1)
r = read(fd, bufs->iov_base, bufs->iov_len);
else if (nbufs > 1)
r = readv(fd, bufs, nbufs);
} else {
if (nbufs == 1)
r = pread(fd, bufs->iov_base, bufs->iov_len, off);
else if (nbufs > 1)
r = preadv(fd, bufs, nbufs, off);
}
#ifdef __PASE__
/* PASE returns EOPNOTSUPP when reading a directory, convert to EISDIR */
if (r == -1 && errno == EOPNOTSUPP) {
struct stat buf;
ssize_t rc;
rc = uv__fstat(fd, &buf);
if (rc == 0 && S_ISDIR(buf.st_mode)) {
errno = EISDIR;
}
}
#endif
/* We don't own the buffer list in the synchronous case. */
if (req->cb != NULL)
if (req->bufs != req->bufsml)
uv__free(req->bufs);
req->bufs = NULL;
req->nbufs = 0;
return r;
}
static int uv__fs_scandir_filter(const uv__dirent_t* dent) {
return strcmp(dent->d_name, ".") != 0 && strcmp(dent->d_name, "..") != 0;
}
static int uv__fs_scandir_sort(const uv__dirent_t** a, const uv__dirent_t** b) {
return strcmp((*a)->d_name, (*b)->d_name);
}
static ssize_t uv__fs_scandir(uv_fs_t* req) {
uv__dirent_t** dents;
int n;
dents = NULL;
n = scandir(req->path, &dents, uv__fs_scandir_filter, uv__fs_scandir_sort);
/* NOTE: We will use nbufs as an index field */
req->nbufs = 0;
if (n == 0) {
/* OS X still needs to deallocate some memory.
* Memory was allocated using the system allocator, so use free() here.
*/
free(dents);
dents = NULL;
} else if (n == -1) {
return n;
}
req->ptr = dents;
return n;
}
static int uv__fs_opendir(uv_fs_t* req) {
uv_dir_t* dir;
dir = uv__malloc(sizeof(*dir));
if (dir == NULL)
goto error;
dir->dir = opendir(req->path);
if (dir->dir == NULL)
goto error;
req->ptr = dir;
return 0;
error:
uv__free(dir);
req->ptr = NULL;
return -1;
}
static int uv__fs_readdir(uv_fs_t* req) {
uv_dir_t* dir;
uv_dirent_t* dirent;
struct dirent* res;
unsigned int dirent_idx;
unsigned int i;
dir = req->ptr;
dirent_idx = 0;
while (dirent_idx < dir->nentries) {
/* readdir() returns NULL on end of directory, as well as on error. errno
is used to differentiate between the two conditions. */
errno = 0;
res = readdir(dir->dir);
if (res == NULL) {
if (errno != 0)
goto error;
break;
}
if (strcmp(res->d_name, ".") == 0 || strcmp(res->d_name, "..") == 0)
continue;
dirent = &dir->dirents[dirent_idx];
dirent->name = uv__strdup(res->d_name);
if (dirent->name == NULL)
goto error;
dirent->type = uv__fs_get_dirent_type(res);
++dirent_idx;
}
return dirent_idx;
error:
for (i = 0; i < dirent_idx; ++i) {
uv__free((char*) dir->dirents[i].name);
dir->dirents[i].name = NULL;
}
return -1;
}
static int uv__fs_closedir(uv_fs_t* req) {
uv_dir_t* dir;
dir = req->ptr;
if (dir->dir != NULL) {
closedir(dir->dir);
dir->dir = NULL;
}
uv__free(req->ptr);
req->ptr = NULL;
return 0;
}
static int uv__fs_statfs(uv_fs_t* req) {
uv_statfs_t* stat_fs;
#if defined(__sun) || \
defined(__MVS__) || \
defined(__NetBSD__) || \
defined(__HAIKU__) || \
defined(__QNX__)
struct statvfs buf;
if (0 != statvfs(req->path, &buf))
#else
struct statfs buf;
if (0 != statfs(req->path, &buf))
#endif /* defined(__sun) */
return -1;
stat_fs = uv__malloc(sizeof(*stat_fs));
if (stat_fs == NULL) {
errno = ENOMEM;
return -1;
}
#if defined(__sun) || \
defined(__MVS__) || \
defined(__OpenBSD__) || \
defined(__NetBSD__) || \
defined(__HAIKU__) || \
defined(__QNX__)
stat_fs->f_type = 0; /* f_type is not supported. */
#else
stat_fs->f_type = buf.f_type;
#endif
stat_fs->f_bsize = buf.f_bsize;
stat_fs->f_blocks = buf.f_blocks;
stat_fs->f_bfree = buf.f_bfree;
stat_fs->f_bavail = buf.f_bavail;
stat_fs->f_files = buf.f_files;
stat_fs->f_ffree = buf.f_ffree;
req->ptr = stat_fs;
return 0;
}
static ssize_t uv__fs_pathmax_size(const char* path) {
ssize_t pathmax;
pathmax = pathconf(path, _PC_PATH_MAX);
if (pathmax == -1)
pathmax = UV__PATH_MAX;
return pathmax;
}
static ssize_t uv__fs_readlink(uv_fs_t* req) {
ssize_t maxlen;
ssize_t len;
char* buf;
#if defined(_POSIX_PATH_MAX) || defined(PATH_MAX)
maxlen = uv__fs_pathmax_size(req->path);
#else
/* We may not have a real PATH_MAX. Read size of link. */
struct stat st;
int ret;
ret = uv__lstat(req->path, &st);
if (ret != 0)
return -1;
if (!S_ISLNK(st.st_mode)) {
errno = EINVAL;
return -1;
}
maxlen = st.st_size;
/* According to readlink(2) lstat can report st_size == 0
for some symlinks, such as those in /proc or /sys. */
if (maxlen == 0)
maxlen = uv__fs_pathmax_size(req->path);
#endif
buf = uv__malloc(maxlen);
if (buf == NULL) {
errno = ENOMEM;
return -1;
}
#if defined(__MVS__)
len = os390_readlink(req->path, buf, maxlen);
#else
len = readlink(req->path, buf, maxlen);
#endif
if (len == -1) {
uv__free(buf);
return -1;
}
/* Uncommon case: resize to make room for the trailing nul byte. */
if (len == maxlen) {
buf = uv__reallocf(buf, len + 1);
if (buf == NULL)
return -1;
}
buf[len] = '\0';
req->ptr = buf;
return 0;
}
static ssize_t uv__fs_realpath(uv_fs_t* req) {
char* buf;
#if defined(_POSIX_VERSION) && _POSIX_VERSION >= 200809L
buf = realpath(req->path, NULL);
if (buf == NULL)
return -1;
#else
ssize_t len;
len = uv__fs_pathmax_size(req->path);
buf = uv__malloc(len + 1);
if (buf == NULL) {
errno = ENOMEM;
return -1;
}
if (realpath(req->path, buf) == NULL) {
uv__free(buf);
return -1;
}
#endif
req->ptr = buf;
return 0;
}
static ssize_t uv__fs_sendfile_emul(uv_fs_t* req) {
struct pollfd pfd;
int use_pread;
off_t offset;
ssize_t nsent;
ssize_t nread;
ssize_t nwritten;
size_t buflen;
size_t len;
ssize_t n;
int in_fd;
int out_fd;
char buf[8192];
len = req->bufsml[0].len;
in_fd = req->flags;
out_fd = req->file;
offset = req->off;
use_pread = 1;
/* Here are the rules regarding errors:
*
* 1. Read errors are reported only if nsent==0, otherwise we return nsent.
* The user needs to know that some data has already been sent, to stop
* them from sending it twice.
*
* 2. Write errors are always reported. Write errors are bad because they
* mean data loss: we've read data but now we can't write it out.
*
* We try to use pread() and fall back to regular read() if the source fd
* doesn't support positional reads, for example when it's a pipe fd.
*
* If we get EAGAIN when writing to the target fd, we poll() on it until
* it becomes writable again.
*
* FIXME: If we get a write error when use_pread==1, it should be safe to
* return the number of sent bytes instead of an error because pread()
* is, in theory, idempotent. However, special files in /dev or /proc
* may support pread() but not necessarily return the same data on
* successive reads.
*
* FIXME: There is no way now to signal that we managed to send *some* data
* before a write error.
*/
for (nsent = 0; (size_t) nsent < len; ) {
buflen = len - nsent;
if (buflen > sizeof(buf))
buflen = sizeof(buf);
do
if (use_pread)
nread = pread(in_fd, buf, buflen, offset);
else
nread = read(in_fd, buf, buflen);
while (nread == -1 && errno == EINTR);
if (nread == 0)
goto out;
if (nread == -1) {
if (use_pread && nsent == 0 && (errno == EIO || errno == ESPIPE)) {
use_pread = 0;
continue;
}
if (nsent == 0)
nsent = -1;
goto out;
}
for (nwritten = 0; nwritten < nread; ) {
do
n = write(out_fd, buf + nwritten, nread - nwritten);
while (n == -1 && errno == EINTR);
if (n != -1) {
nwritten += n;
continue;
}
if (errno != EAGAIN && errno != EWOULDBLOCK) {
nsent = -1;
goto out;
}
pfd.fd = out_fd;
pfd.events = POLLOUT;
pfd.revents = 0;
do
n = poll(&pfd, 1, -1);
while (n == -1 && errno == EINTR);
if (n == -1 || (pfd.revents & ~POLLOUT) != 0) {
errno = EIO;
nsent = -1;
goto out;
}
}
offset += nread;
nsent += nread;
}
out:
if (nsent != -1)
req->off = offset;
return nsent;
}
#ifdef __linux__
/* Pre-4.20 kernels have a bug where CephFS uses the RADOS copy-from command
* in copy_file_range() when it shouldn't. There is no workaround except to
* fall back to a regular copy.
*/
static int uv__is_buggy_cephfs(int fd) {
struct statfs s;
if (-1 == fstatfs(fd, &s))
return 0;
if (s.f_type != /* CephFS */ 0xC36400)
return 0;
return uv__kernel_version() < /* 4.20.0 */ 0x041400;
}
static int uv__is_cifs_or_smb(int fd) {
struct statfs s;
if (-1 == fstatfs(fd, &s))
return 0;
switch ((unsigned) s.f_type) {
case 0x0000517Bu: /* SMB */
case 0xFE534D42u: /* SMB2 */
case 0xFF534D42u: /* CIFS */
return 1;
}
return 0;
}
static ssize_t uv__fs_try_copy_file_range(int in_fd, off_t* off,
int out_fd, size_t len) {
static _Atomic int no_copy_file_range_support;
ssize_t r;
if (atomic_load_explicit(&no_copy_file_range_support, memory_order_relaxed)) {
errno = ENOSYS;
return -1;
}
r = uv__fs_copy_file_range(in_fd, off, out_fd, NULL, len, 0);
if (r != -1)
return r;
switch (errno) {
case EACCES:
/* Pre-4.20 kernels have a bug where CephFS uses the RADOS
* copy-from command when it shouldn't.
*/
if (uv__is_buggy_cephfs(in_fd))
errno = ENOSYS; /* Use fallback. */
break;
case ENOSYS:
atomic_store_explicit(&no_copy_file_range_support, 1, memory_order_relaxed);
break;
case EPERM:
/* It's been reported that CIFS spuriously fails.
* Consider it a transient error.
*/
if (uv__is_cifs_or_smb(out_fd))
errno = ENOSYS; /* Use fallback. */
break;
case ENOTSUP:
case EXDEV:
/* ENOTSUP - it could work on another file system type.
* EXDEV - it will not work when in_fd and out_fd are not on the same
* mounted filesystem (pre Linux 5.3)
*/
errno = ENOSYS; /* Use fallback. */
break;
}
return -1;
}
#endif /* __linux__ */
static ssize_t uv__fs_sendfile(uv_fs_t* req) {
int in_fd;
int out_fd;
in_fd = req->flags;
out_fd = req->file;
#if defined(__linux__) || defined(__sun)
{
off_t off;
ssize_t r;
size_t len;
int try_sendfile;
off = req->off;
len = req->bufsml[0].len;
try_sendfile = 1;
#ifdef __linux__
r = uv__fs_try_copy_file_range(in_fd, &off, out_fd, len);
try_sendfile = (r == -1 && errno == ENOSYS);
#endif
if (try_sendfile)
r = sendfile(out_fd, in_fd, &off, len);
/* sendfile() on SunOS returns EINVAL if the target fd is not a socket but
* it still writes out data. Fortunately, we can detect it by checking if
* the offset has been updated.
*/
if (r != -1 || off > req->off) {
r = off - req->off;
req->off = off;
return r;
}
if (errno == EINVAL ||
errno == EIO ||
errno == ENOTSOCK ||
errno == EXDEV) {
errno = 0;
return uv__fs_sendfile_emul(req);
}
return -1;
}
#elif defined(__APPLE__) || defined(__DragonFly__) || defined(__FreeBSD__)
{
off_t len;
ssize_t r;
/* sendfile() on FreeBSD and Darwin returns EAGAIN if the target fd is in
* non-blocking mode and not all data could be written. If a non-zero
* number of bytes have been sent, we don't consider it an error.
*/
#if defined(__FreeBSD__) || defined(__DragonFly__)
#if defined(__FreeBSD__)
off_t off;
off = req->off;
r = uv__fs_copy_file_range(in_fd, &off, out_fd, NULL, req->bufsml[0].len, 0);
if (r >= 0) {
r = off - req->off;
req->off = off;
return r;
}
#endif
len = 0;
r = sendfile(in_fd, out_fd, req->off, req->bufsml[0].len, NULL, &len, 0);
#else
/* The darwin sendfile takes len as an input for the length to send,
* so make sure to initialize it with the caller's value. */
len = req->bufsml[0].len;
r = sendfile(in_fd, out_fd, req->off, &len, NULL, 0);
#endif
/*
* The man page for sendfile(2) on DragonFly states that `len` contains
* a meaningful value ONLY in case of EAGAIN and EINTR.
* Nothing is said about it's value in case of other errors, so better
* not depend on the potential wrong assumption that is was not modified