This source file includes following definitions.
- page_cache_pipe_buf_steal
- page_cache_pipe_buf_release
- page_cache_pipe_buf_confirm
- user_page_pipe_buf_steal
- wakeup_pipe_readers
- splice_to_pipe
- add_to_pipe
- splice_grow_spd
- splice_shrink_spd
- generic_file_splice_read
- generic_pipe_buf_nosteal
- kernel_readv
- default_file_splice_read
- pipe_to_sendpage
- wakeup_pipe_writers
- splice_from_pipe_feed
- splice_from_pipe_next
- splice_from_pipe_begin
- splice_from_pipe_end
- __splice_from_pipe
- splice_from_pipe
- iter_file_splice_write
- write_pipe_buf
- default_file_splice_write
- generic_splice_sendpage
- do_splice_from
- do_splice_to
- splice_direct_to_actor
- direct_splice_actor
- do_splice_direct
- wait_for_space
- do_splice
- iter_to_pipe
- pipe_to_user
- vmsplice_to_user
- vmsplice_to_pipe
- vmsplice_type
- do_vmsplice
- SYSCALL_DEFINE4
- COMPAT_SYSCALL_DEFINE4
- SYSCALL_DEFINE6
- ipipe_prep
- opipe_prep
- splice_pipe_to_pipe
- link_pipe
- do_tee
- SYSCALL_DEFINE4
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21 #include <linux/bvec.h>
22 #include <linux/fs.h>
23 #include <linux/file.h>
24 #include <linux/pagemap.h>
25 #include <linux/splice.h>
26 #include <linux/memcontrol.h>
27 #include <linux/mm_inline.h>
28 #include <linux/swap.h>
29 #include <linux/writeback.h>
30 #include <linux/export.h>
31 #include <linux/syscalls.h>
32 #include <linux/uio.h>
33 #include <linux/security.h>
34 #include <linux/gfp.h>
35 #include <linux/socket.h>
36 #include <linux/compat.h>
37 #include <linux/sched/signal.h>
38
39 #include "internal.h"
40
41
42
43
44
45
46
47 static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
48 struct pipe_buffer *buf)
49 {
50 struct page *page = buf->page;
51 struct address_space *mapping;
52
53 lock_page(page);
54
55 mapping = page_mapping(page);
56 if (mapping) {
57 WARN_ON(!PageUptodate(page));
58
59
60
61
62
63
64
65
66
67 wait_on_page_writeback(page);
68
69 if (page_has_private(page) &&
70 !try_to_release_page(page, GFP_KERNEL))
71 goto out_unlock;
72
73
74
75
76
77 if (remove_mapping(mapping, page)) {
78 buf->flags |= PIPE_BUF_FLAG_LRU;
79 return 0;
80 }
81 }
82
83
84
85
86
87 out_unlock:
88 unlock_page(page);
89 return 1;
90 }
91
92 static void page_cache_pipe_buf_release(struct pipe_inode_info *pipe,
93 struct pipe_buffer *buf)
94 {
95 put_page(buf->page);
96 buf->flags &= ~PIPE_BUF_FLAG_LRU;
97 }
98
99
100
101
102
103 static int page_cache_pipe_buf_confirm(struct pipe_inode_info *pipe,
104 struct pipe_buffer *buf)
105 {
106 struct page *page = buf->page;
107 int err;
108
109 if (!PageUptodate(page)) {
110 lock_page(page);
111
112
113
114
115
116 if (!page->mapping) {
117 err = -ENODATA;
118 goto error;
119 }
120
121
122
123
124 if (!PageUptodate(page)) {
125 err = -EIO;
126 goto error;
127 }
128
129
130
131
132 unlock_page(page);
133 }
134
135 return 0;
136 error:
137 unlock_page(page);
138 return err;
139 }
140
141 const struct pipe_buf_operations page_cache_pipe_buf_ops = {
142 .confirm = page_cache_pipe_buf_confirm,
143 .release = page_cache_pipe_buf_release,
144 .steal = page_cache_pipe_buf_steal,
145 .get = generic_pipe_buf_get,
146 };
147
148 static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe,
149 struct pipe_buffer *buf)
150 {
151 if (!(buf->flags & PIPE_BUF_FLAG_GIFT))
152 return 1;
153
154 buf->flags |= PIPE_BUF_FLAG_LRU;
155 return generic_pipe_buf_steal(pipe, buf);
156 }
157
158 static const struct pipe_buf_operations user_page_pipe_buf_ops = {
159 .confirm = generic_pipe_buf_confirm,
160 .release = page_cache_pipe_buf_release,
161 .steal = user_page_pipe_buf_steal,
162 .get = generic_pipe_buf_get,
163 };
164
165 static void wakeup_pipe_readers(struct pipe_inode_info *pipe)
166 {
167 smp_mb();
168 if (waitqueue_active(&pipe->wait))
169 wake_up_interruptible(&pipe->wait);
170 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
171 }
172
173
174
175
176
177
178
179
180
181
182
183
184 ssize_t splice_to_pipe(struct pipe_inode_info *pipe,
185 struct splice_pipe_desc *spd)
186 {
187 unsigned int spd_pages = spd->nr_pages;
188 int ret = 0, page_nr = 0;
189
190 if (!spd_pages)
191 return 0;
192
193 if (unlikely(!pipe->readers)) {
194 send_sig(SIGPIPE, current, 0);
195 ret = -EPIPE;
196 goto out;
197 }
198
199 while (pipe->nrbufs < pipe->buffers) {
200 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
201 struct pipe_buffer *buf = pipe->bufs + newbuf;
202
203 buf->page = spd->pages[page_nr];
204 buf->offset = spd->partial[page_nr].offset;
205 buf->len = spd->partial[page_nr].len;
206 buf->private = spd->partial[page_nr].private;
207 buf->ops = spd->ops;
208 buf->flags = 0;
209
210 pipe->nrbufs++;
211 page_nr++;
212 ret += buf->len;
213
214 if (!--spd->nr_pages)
215 break;
216 }
217
218 if (!ret)
219 ret = -EAGAIN;
220
221 out:
222 while (page_nr < spd_pages)
223 spd->spd_release(spd, page_nr++);
224
225 return ret;
226 }
227 EXPORT_SYMBOL_GPL(splice_to_pipe);
228
229 ssize_t add_to_pipe(struct pipe_inode_info *pipe, struct pipe_buffer *buf)
230 {
231 int ret;
232
233 if (unlikely(!pipe->readers)) {
234 send_sig(SIGPIPE, current, 0);
235 ret = -EPIPE;
236 } else if (pipe->nrbufs == pipe->buffers) {
237 ret = -EAGAIN;
238 } else {
239 int newbuf = (pipe->curbuf + pipe->nrbufs) & (pipe->buffers - 1);
240 pipe->bufs[newbuf] = *buf;
241 pipe->nrbufs++;
242 return buf->len;
243 }
244 pipe_buf_release(pipe, buf);
245 return ret;
246 }
247 EXPORT_SYMBOL(add_to_pipe);
248
249
250
251
252
253 int splice_grow_spd(const struct pipe_inode_info *pipe, struct splice_pipe_desc *spd)
254 {
255 unsigned int buffers = READ_ONCE(pipe->buffers);
256
257 spd->nr_pages_max = buffers;
258 if (buffers <= PIPE_DEF_BUFFERS)
259 return 0;
260
261 spd->pages = kmalloc_array(buffers, sizeof(struct page *), GFP_KERNEL);
262 spd->partial = kmalloc_array(buffers, sizeof(struct partial_page),
263 GFP_KERNEL);
264
265 if (spd->pages && spd->partial)
266 return 0;
267
268 kfree(spd->pages);
269 kfree(spd->partial);
270 return -ENOMEM;
271 }
272
273 void splice_shrink_spd(struct splice_pipe_desc *spd)
274 {
275 if (spd->nr_pages_max <= PIPE_DEF_BUFFERS)
276 return;
277
278 kfree(spd->pages);
279 kfree(spd->partial);
280 }
281
282
283
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287
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291
292
293
294
295 ssize_t generic_file_splice_read(struct file *in, loff_t *ppos,
296 struct pipe_inode_info *pipe, size_t len,
297 unsigned int flags)
298 {
299 struct iov_iter to;
300 struct kiocb kiocb;
301 int idx, ret;
302
303 iov_iter_pipe(&to, READ, pipe, len);
304 idx = to.idx;
305 init_sync_kiocb(&kiocb, in);
306 kiocb.ki_pos = *ppos;
307 ret = call_read_iter(in, &kiocb, &to);
308 if (ret > 0) {
309 *ppos = kiocb.ki_pos;
310 file_accessed(in);
311 } else if (ret < 0) {
312 to.idx = idx;
313 to.iov_offset = 0;
314 iov_iter_advance(&to, 0);
315
316
317
318
319 if (ret == -EFAULT)
320 ret = -EAGAIN;
321 }
322
323 return ret;
324 }
325 EXPORT_SYMBOL(generic_file_splice_read);
326
327 const struct pipe_buf_operations default_pipe_buf_ops = {
328 .confirm = generic_pipe_buf_confirm,
329 .release = generic_pipe_buf_release,
330 .steal = generic_pipe_buf_steal,
331 .get = generic_pipe_buf_get,
332 };
333
334 int generic_pipe_buf_nosteal(struct pipe_inode_info *pipe,
335 struct pipe_buffer *buf)
336 {
337 return 1;
338 }
339
340
341 const struct pipe_buf_operations nosteal_pipe_buf_ops = {
342 .confirm = generic_pipe_buf_confirm,
343 .release = generic_pipe_buf_release,
344 .steal = generic_pipe_buf_nosteal,
345 .get = generic_pipe_buf_get,
346 };
347 EXPORT_SYMBOL(nosteal_pipe_buf_ops);
348
349 static ssize_t kernel_readv(struct file *file, const struct kvec *vec,
350 unsigned long vlen, loff_t offset)
351 {
352 mm_segment_t old_fs;
353 loff_t pos = offset;
354 ssize_t res;
355
356 old_fs = get_fs();
357 set_fs(KERNEL_DS);
358
359 res = vfs_readv(file, (const struct iovec __user *)vec, vlen, &pos, 0);
360 set_fs(old_fs);
361
362 return res;
363 }
364
365 static ssize_t default_file_splice_read(struct file *in, loff_t *ppos,
366 struct pipe_inode_info *pipe, size_t len,
367 unsigned int flags)
368 {
369 struct kvec *vec, __vec[PIPE_DEF_BUFFERS];
370 struct iov_iter to;
371 struct page **pages;
372 unsigned int nr_pages;
373 size_t offset, base, copied = 0;
374 ssize_t res;
375 int i;
376
377 if (pipe->nrbufs == pipe->buffers)
378 return -EAGAIN;
379
380
381
382
383
384 offset = *ppos & ~PAGE_MASK;
385
386 iov_iter_pipe(&to, READ, pipe, len + offset);
387
388 res = iov_iter_get_pages_alloc(&to, &pages, len + offset, &base);
389 if (res <= 0)
390 return -ENOMEM;
391
392 nr_pages = DIV_ROUND_UP(res + base, PAGE_SIZE);
393
394 vec = __vec;
395 if (nr_pages > PIPE_DEF_BUFFERS) {
396 vec = kmalloc_array(nr_pages, sizeof(struct kvec), GFP_KERNEL);
397 if (unlikely(!vec)) {
398 res = -ENOMEM;
399 goto out;
400 }
401 }
402
403 pipe->bufs[to.idx].offset = offset;
404 pipe->bufs[to.idx].len -= offset;
405
406 for (i = 0; i < nr_pages; i++) {
407 size_t this_len = min_t(size_t, len, PAGE_SIZE - offset);
408 vec[i].iov_base = page_address(pages[i]) + offset;
409 vec[i].iov_len = this_len;
410 len -= this_len;
411 offset = 0;
412 }
413
414 res = kernel_readv(in, vec, nr_pages, *ppos);
415 if (res > 0) {
416 copied = res;
417 *ppos += res;
418 }
419
420 if (vec != __vec)
421 kfree(vec);
422 out:
423 for (i = 0; i < nr_pages; i++)
424 put_page(pages[i]);
425 kvfree(pages);
426 iov_iter_advance(&to, copied);
427 return res;
428 }
429
430
431
432
433
434 static int pipe_to_sendpage(struct pipe_inode_info *pipe,
435 struct pipe_buffer *buf, struct splice_desc *sd)
436 {
437 struct file *file = sd->u.file;
438 loff_t pos = sd->pos;
439 int more;
440
441 if (!likely(file->f_op->sendpage))
442 return -EINVAL;
443
444 more = (sd->flags & SPLICE_F_MORE) ? MSG_MORE : 0;
445
446 if (sd->len < sd->total_len && pipe->nrbufs > 1)
447 more |= MSG_SENDPAGE_NOTLAST;
448
449 return file->f_op->sendpage(file, buf->page, buf->offset,
450 sd->len, &pos, more);
451 }
452
453 static void wakeup_pipe_writers(struct pipe_inode_info *pipe)
454 {
455 smp_mb();
456 if (waitqueue_active(&pipe->wait))
457 wake_up_interruptible(&pipe->wait);
458 kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT);
459 }
460
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475
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477
478
479
480
481 static int splice_from_pipe_feed(struct pipe_inode_info *pipe, struct splice_desc *sd,
482 splice_actor *actor)
483 {
484 int ret;
485
486 while (pipe->nrbufs) {
487 struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
488
489 sd->len = buf->len;
490 if (sd->len > sd->total_len)
491 sd->len = sd->total_len;
492
493 ret = pipe_buf_confirm(pipe, buf);
494 if (unlikely(ret)) {
495 if (ret == -ENODATA)
496 ret = 0;
497 return ret;
498 }
499
500 ret = actor(pipe, buf, sd);
501 if (ret <= 0)
502 return ret;
503
504 buf->offset += ret;
505 buf->len -= ret;
506
507 sd->num_spliced += ret;
508 sd->len -= ret;
509 sd->pos += ret;
510 sd->total_len -= ret;
511
512 if (!buf->len) {
513 pipe_buf_release(pipe, buf);
514 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
515 pipe->nrbufs--;
516 if (pipe->files)
517 sd->need_wakeup = true;
518 }
519
520 if (!sd->total_len)
521 return 0;
522 }
523
524 return 1;
525 }
526
527
528
529
530
531
532
533
534
535
536
537 static int splice_from_pipe_next(struct pipe_inode_info *pipe, struct splice_desc *sd)
538 {
539
540
541
542
543 if (signal_pending(current))
544 return -ERESTARTSYS;
545
546 while (!pipe->nrbufs) {
547 if (!pipe->writers)
548 return 0;
549
550 if (!pipe->waiting_writers && sd->num_spliced)
551 return 0;
552
553 if (sd->flags & SPLICE_F_NONBLOCK)
554 return -EAGAIN;
555
556 if (signal_pending(current))
557 return -ERESTARTSYS;
558
559 if (sd->need_wakeup) {
560 wakeup_pipe_writers(pipe);
561 sd->need_wakeup = false;
562 }
563
564 pipe_wait(pipe);
565 }
566
567 return 1;
568 }
569
570
571
572
573
574
575
576
577
578
579 static void splice_from_pipe_begin(struct splice_desc *sd)
580 {
581 sd->num_spliced = 0;
582 sd->need_wakeup = false;
583 }
584
585
586
587
588
589
590
591
592
593
594
595 static void splice_from_pipe_end(struct pipe_inode_info *pipe, struct splice_desc *sd)
596 {
597 if (sd->need_wakeup)
598 wakeup_pipe_writers(pipe);
599 }
600
601
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608
609
610
611
612
613
614 ssize_t __splice_from_pipe(struct pipe_inode_info *pipe, struct splice_desc *sd,
615 splice_actor *actor)
616 {
617 int ret;
618
619 splice_from_pipe_begin(sd);
620 do {
621 cond_resched();
622 ret = splice_from_pipe_next(pipe, sd);
623 if (ret > 0)
624 ret = splice_from_pipe_feed(pipe, sd, actor);
625 } while (ret > 0);
626 splice_from_pipe_end(pipe, sd);
627
628 return sd->num_spliced ? sd->num_spliced : ret;
629 }
630 EXPORT_SYMBOL(__splice_from_pipe);
631
632
633
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640
641
642
643
644
645
646 ssize_t splice_from_pipe(struct pipe_inode_info *pipe, struct file *out,
647 loff_t *ppos, size_t len, unsigned int flags,
648 splice_actor *actor)
649 {
650 ssize_t ret;
651 struct splice_desc sd = {
652 .total_len = len,
653 .flags = flags,
654 .pos = *ppos,
655 .u.file = out,
656 };
657
658 pipe_lock(pipe);
659 ret = __splice_from_pipe(pipe, &sd, actor);
660 pipe_unlock(pipe);
661
662 return ret;
663 }
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679 ssize_t
680 iter_file_splice_write(struct pipe_inode_info *pipe, struct file *out,
681 loff_t *ppos, size_t len, unsigned int flags)
682 {
683 struct splice_desc sd = {
684 .total_len = len,
685 .flags = flags,
686 .pos = *ppos,
687 .u.file = out,
688 };
689 int nbufs = pipe->buffers;
690 struct bio_vec *array = kcalloc(nbufs, sizeof(struct bio_vec),
691 GFP_KERNEL);
692 ssize_t ret;
693
694 if (unlikely(!array))
695 return -ENOMEM;
696
697 pipe_lock(pipe);
698
699 splice_from_pipe_begin(&sd);
700 while (sd.total_len) {
701 struct iov_iter from;
702 size_t left;
703 int n, idx;
704
705 ret = splice_from_pipe_next(pipe, &sd);
706 if (ret <= 0)
707 break;
708
709 if (unlikely(nbufs < pipe->buffers)) {
710 kfree(array);
711 nbufs = pipe->buffers;
712 array = kcalloc(nbufs, sizeof(struct bio_vec),
713 GFP_KERNEL);
714 if (!array) {
715 ret = -ENOMEM;
716 break;
717 }
718 }
719
720
721 left = sd.total_len;
722 for (n = 0, idx = pipe->curbuf; left && n < pipe->nrbufs; n++, idx++) {
723 struct pipe_buffer *buf = pipe->bufs + idx;
724 size_t this_len = buf->len;
725
726 if (this_len > left)
727 this_len = left;
728
729 if (idx == pipe->buffers - 1)
730 idx = -1;
731
732 ret = pipe_buf_confirm(pipe, buf);
733 if (unlikely(ret)) {
734 if (ret == -ENODATA)
735 ret = 0;
736 goto done;
737 }
738
739 array[n].bv_page = buf->page;
740 array[n].bv_len = this_len;
741 array[n].bv_offset = buf->offset;
742 left -= this_len;
743 }
744
745 iov_iter_bvec(&from, WRITE, array, n, sd.total_len - left);
746 ret = vfs_iter_write(out, &from, &sd.pos, 0);
747 if (ret <= 0)
748 break;
749
750 sd.num_spliced += ret;
751 sd.total_len -= ret;
752 *ppos = sd.pos;
753
754
755 while (ret) {
756 struct pipe_buffer *buf = pipe->bufs + pipe->curbuf;
757 if (ret >= buf->len) {
758 ret -= buf->len;
759 buf->len = 0;
760 pipe_buf_release(pipe, buf);
761 pipe->curbuf = (pipe->curbuf + 1) & (pipe->buffers - 1);
762 pipe->nrbufs--;
763 if (pipe->files)
764 sd.need_wakeup = true;
765 } else {
766 buf->offset += ret;
767 buf->len -= ret;
768 ret = 0;
769 }
770 }
771 }
772 done:
773 kfree(array);
774 splice_from_pipe_end(pipe, &sd);
775
776 pipe_unlock(pipe);
777
778 if (sd.num_spliced)
779 ret = sd.num_spliced;
780
781 return ret;
782 }
783
784 EXPORT_SYMBOL(iter_file_splice_write);
785
786 static int write_pipe_buf(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
787 struct splice_desc *sd)
788 {
789 int ret;
790 void *data;
791 loff_t tmp = sd->pos;
792
793 data = kmap(buf->page);
794 ret = __kernel_write(sd->u.file, data + buf->offset, sd->len, &tmp);
795 kunmap(buf->page);
796
797 return ret;
798 }
799
800 static ssize_t default_file_splice_write(struct pipe_inode_info *pipe,
801 struct file *out, loff_t *ppos,
802 size_t len, unsigned int flags)
803 {
804 ssize_t ret;
805
806 ret = splice_from_pipe(pipe, out, ppos, len, flags, write_pipe_buf);
807 if (ret > 0)
808 *ppos += ret;
809
810 return ret;
811 }
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826 ssize_t generic_splice_sendpage(struct pipe_inode_info *pipe, struct file *out,
827 loff_t *ppos, size_t len, unsigned int flags)
828 {
829 return splice_from_pipe(pipe, out, ppos, len, flags, pipe_to_sendpage);
830 }
831
832 EXPORT_SYMBOL(generic_splice_sendpage);
833
834
835
836
837 static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
838 loff_t *ppos, size_t len, unsigned int flags)
839 {
840 ssize_t (*splice_write)(struct pipe_inode_info *, struct file *,
841 loff_t *, size_t, unsigned int);
842
843 if (out->f_op->splice_write)
844 splice_write = out->f_op->splice_write;
845 else
846 splice_write = default_file_splice_write;
847
848 return splice_write(pipe, out, ppos, len, flags);
849 }
850
851
852
853
854 static long do_splice_to(struct file *in, loff_t *ppos,
855 struct pipe_inode_info *pipe, size_t len,
856 unsigned int flags)
857 {
858 ssize_t (*splice_read)(struct file *, loff_t *,
859 struct pipe_inode_info *, size_t, unsigned int);
860 int ret;
861
862 if (unlikely(!(in->f_mode & FMODE_READ)))
863 return -EBADF;
864
865 ret = rw_verify_area(READ, in, ppos, len);
866 if (unlikely(ret < 0))
867 return ret;
868
869 if (unlikely(len > MAX_RW_COUNT))
870 len = MAX_RW_COUNT;
871
872 if (in->f_op->splice_read)
873 splice_read = in->f_op->splice_read;
874 else
875 splice_read = default_file_splice_read;
876
877 return splice_read(in, ppos, pipe, len, flags);
878 }
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893 ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
894 splice_direct_actor *actor)
895 {
896 struct pipe_inode_info *pipe;
897 long ret, bytes;
898 umode_t i_mode;
899 size_t len;
900 int i, flags, more;
901
902
903
904
905
906
907 i_mode = file_inode(in)->i_mode;
908 if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode)))
909 return -EINVAL;
910
911
912
913
914
915 pipe = current->splice_pipe;
916 if (unlikely(!pipe)) {
917 pipe = alloc_pipe_info();
918 if (!pipe)
919 return -ENOMEM;
920
921
922
923
924
925
926 pipe->readers = 1;
927
928 current->splice_pipe = pipe;
929 }
930
931
932
933
934 ret = 0;
935 bytes = 0;
936 len = sd->total_len;
937 flags = sd->flags;
938
939
940
941
942 sd->flags &= ~SPLICE_F_NONBLOCK;
943 more = sd->flags & SPLICE_F_MORE;
944
945 WARN_ON_ONCE(pipe->nrbufs != 0);
946
947 while (len) {
948 unsigned int pipe_pages;
949 size_t read_len;
950 loff_t pos = sd->pos, prev_pos = pos;
951
952
953 pipe_pages = pipe->buffers - pipe->nrbufs;
954 read_len = min(len, (size_t)pipe_pages << PAGE_SHIFT);
955 ret = do_splice_to(in, &pos, pipe, read_len, flags);
956 if (unlikely(ret <= 0))
957 goto out_release;
958
959 read_len = ret;
960 sd->total_len = read_len;
961
962
963
964
965
966
967 if (read_len < len)
968 sd->flags |= SPLICE_F_MORE;
969 else if (!more)
970 sd->flags &= ~SPLICE_F_MORE;
971
972
973
974
975
976 ret = actor(pipe, sd);
977 if (unlikely(ret <= 0)) {
978 sd->pos = prev_pos;
979 goto out_release;
980 }
981
982 bytes += ret;
983 len -= ret;
984 sd->pos = pos;
985
986 if (ret < read_len) {
987 sd->pos = prev_pos + ret;
988 goto out_release;
989 }
990 }
991
992 done:
993 pipe->nrbufs = pipe->curbuf = 0;
994 file_accessed(in);
995 return bytes;
996
997 out_release:
998
999
1000
1001
1002 for (i = 0; i < pipe->buffers; i++) {
1003 struct pipe_buffer *buf = pipe->bufs + i;
1004
1005 if (buf->ops)
1006 pipe_buf_release(pipe, buf);
1007 }
1008
1009 if (!bytes)
1010 bytes = ret;
1011
1012 goto done;
1013 }
1014 EXPORT_SYMBOL(splice_direct_to_actor);
1015
1016 static int direct_splice_actor(struct pipe_inode_info *pipe,
1017 struct splice_desc *sd)
1018 {
1019 struct file *file = sd->u.file;
1020
1021 return do_splice_from(pipe, file, sd->opos, sd->total_len,
1022 sd->flags);
1023 }
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041 long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
1042 loff_t *opos, size_t len, unsigned int flags)
1043 {
1044 struct splice_desc sd = {
1045 .len = len,
1046 .total_len = len,
1047 .flags = flags,
1048 .pos = *ppos,
1049 .u.file = out,
1050 .opos = opos,
1051 };
1052 long ret;
1053
1054 if (unlikely(!(out->f_mode & FMODE_WRITE)))
1055 return -EBADF;
1056
1057 if (unlikely(out->f_flags & O_APPEND))
1058 return -EINVAL;
1059
1060 ret = rw_verify_area(WRITE, out, opos, len);
1061 if (unlikely(ret < 0))
1062 return ret;
1063
1064 ret = splice_direct_to_actor(in, &sd, direct_splice_actor);
1065 if (ret > 0)
1066 *ppos = sd.pos;
1067
1068 return ret;
1069 }
1070 EXPORT_SYMBOL(do_splice_direct);
1071
1072 static int wait_for_space(struct pipe_inode_info *pipe, unsigned flags)
1073 {
1074 for (;;) {
1075 if (unlikely(!pipe->readers)) {
1076 send_sig(SIGPIPE, current, 0);
1077 return -EPIPE;
1078 }
1079 if (pipe->nrbufs != pipe->buffers)
1080 return 0;
1081 if (flags & SPLICE_F_NONBLOCK)
1082 return -EAGAIN;
1083 if (signal_pending(current))
1084 return -ERESTARTSYS;
1085 pipe->waiting_writers++;
1086 pipe_wait(pipe);
1087 pipe->waiting_writers--;
1088 }
1089 }
1090
1091 static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
1092 struct pipe_inode_info *opipe,
1093 size_t len, unsigned int flags);
1094
1095
1096
1097
1098 static long do_splice(struct file *in, loff_t __user *off_in,
1099 struct file *out, loff_t __user *off_out,
1100 size_t len, unsigned int flags)
1101 {
1102 struct pipe_inode_info *ipipe;
1103 struct pipe_inode_info *opipe;
1104 loff_t offset;
1105 long ret;
1106
1107 ipipe = get_pipe_info(in);
1108 opipe = get_pipe_info(out);
1109
1110 if (ipipe && opipe) {
1111 if (off_in || off_out)
1112 return -ESPIPE;
1113
1114 if (!(in->f_mode & FMODE_READ))
1115 return -EBADF;
1116
1117 if (!(out->f_mode & FMODE_WRITE))
1118 return -EBADF;
1119
1120
1121 if (ipipe == opipe)
1122 return -EINVAL;
1123
1124 if ((in->f_flags | out->f_flags) & O_NONBLOCK)
1125 flags |= SPLICE_F_NONBLOCK;
1126
1127 return splice_pipe_to_pipe(ipipe, opipe, len, flags);
1128 }
1129
1130 if (ipipe) {
1131 if (off_in)
1132 return -ESPIPE;
1133 if (off_out) {
1134 if (!(out->f_mode & FMODE_PWRITE))
1135 return -EINVAL;
1136 if (copy_from_user(&offset, off_out, sizeof(loff_t)))
1137 return -EFAULT;
1138 } else {
1139 offset = out->f_pos;
1140 }
1141
1142 if (unlikely(!(out->f_mode & FMODE_WRITE)))
1143 return -EBADF;
1144
1145 if (unlikely(out->f_flags & O_APPEND))
1146 return -EINVAL;
1147
1148 ret = rw_verify_area(WRITE, out, &offset, len);
1149 if (unlikely(ret < 0))
1150 return ret;
1151
1152 if (in->f_flags & O_NONBLOCK)
1153 flags |= SPLICE_F_NONBLOCK;
1154
1155 file_start_write(out);
1156 ret = do_splice_from(ipipe, out, &offset, len, flags);
1157 file_end_write(out);
1158
1159 if (!off_out)
1160 out->f_pos = offset;
1161 else if (copy_to_user(off_out, &offset, sizeof(loff_t)))
1162 ret = -EFAULT;
1163
1164 return ret;
1165 }
1166
1167 if (opipe) {
1168 if (off_out)
1169 return -ESPIPE;
1170 if (off_in) {
1171 if (!(in->f_mode & FMODE_PREAD))
1172 return -EINVAL;
1173 if (copy_from_user(&offset, off_in, sizeof(loff_t)))
1174 return -EFAULT;
1175 } else {
1176 offset = in->f_pos;
1177 }
1178
1179 if (out->f_flags & O_NONBLOCK)
1180 flags |= SPLICE_F_NONBLOCK;
1181
1182 pipe_lock(opipe);
1183 ret = wait_for_space(opipe, flags);
1184 if (!ret) {
1185 unsigned int pipe_pages;
1186
1187
1188 pipe_pages = opipe->buffers - opipe->nrbufs;
1189 len = min(len, (size_t)pipe_pages << PAGE_SHIFT);
1190
1191 ret = do_splice_to(in, &offset, opipe, len, flags);
1192 }
1193 pipe_unlock(opipe);
1194 if (ret > 0)
1195 wakeup_pipe_readers(opipe);
1196 if (!off_in)
1197 in->f_pos = offset;
1198 else if (copy_to_user(off_in, &offset, sizeof(loff_t)))
1199 ret = -EFAULT;
1200
1201 return ret;
1202 }
1203
1204 return -EINVAL;
1205 }
1206
1207 static int iter_to_pipe(struct iov_iter *from,
1208 struct pipe_inode_info *pipe,
1209 unsigned flags)
1210 {
1211 struct pipe_buffer buf = {
1212 .ops = &user_page_pipe_buf_ops,
1213 .flags = flags
1214 };
1215 size_t total = 0;
1216 int ret = 0;
1217 bool failed = false;
1218
1219 while (iov_iter_count(from) && !failed) {
1220 struct page *pages[16];
1221 ssize_t copied;
1222 size_t start;
1223 int n;
1224
1225 copied = iov_iter_get_pages(from, pages, ~0UL, 16, &start);
1226 if (copied <= 0) {
1227 ret = copied;
1228 break;
1229 }
1230
1231 for (n = 0; copied; n++, start = 0) {
1232 int size = min_t(int, copied, PAGE_SIZE - start);
1233 if (!failed) {
1234 buf.page = pages[n];
1235 buf.offset = start;
1236 buf.len = size;
1237 ret = add_to_pipe(pipe, &buf);
1238 if (unlikely(ret < 0)) {
1239 failed = true;
1240 } else {
1241 iov_iter_advance(from, ret);
1242 total += ret;
1243 }
1244 } else {
1245 put_page(pages[n]);
1246 }
1247 copied -= size;
1248 }
1249 }
1250 return total ? total : ret;
1251 }
1252
1253 static int pipe_to_user(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
1254 struct splice_desc *sd)
1255 {
1256 int n = copy_page_to_iter(buf->page, buf->offset, sd->len, sd->u.data);
1257 return n == sd->len ? n : -EFAULT;
1258 }
1259
1260
1261
1262
1263
1264 static long vmsplice_to_user(struct file *file, struct iov_iter *iter,
1265 unsigned int flags)
1266 {
1267 struct pipe_inode_info *pipe = get_pipe_info(file);
1268 struct splice_desc sd = {
1269 .total_len = iov_iter_count(iter),
1270 .flags = flags,
1271 .u.data = iter
1272 };
1273 long ret = 0;
1274
1275 if (!pipe)
1276 return -EBADF;
1277
1278 if (sd.total_len) {
1279 pipe_lock(pipe);
1280 ret = __splice_from_pipe(pipe, &sd, pipe_to_user);
1281 pipe_unlock(pipe);
1282 }
1283
1284 return ret;
1285 }
1286
1287
1288
1289
1290
1291
1292 static long vmsplice_to_pipe(struct file *file, struct iov_iter *iter,
1293 unsigned int flags)
1294 {
1295 struct pipe_inode_info *pipe;
1296 long ret = 0;
1297 unsigned buf_flag = 0;
1298
1299 if (flags & SPLICE_F_GIFT)
1300 buf_flag = PIPE_BUF_FLAG_GIFT;
1301
1302 pipe = get_pipe_info(file);
1303 if (!pipe)
1304 return -EBADF;
1305
1306 pipe_lock(pipe);
1307 ret = wait_for_space(pipe, flags);
1308 if (!ret)
1309 ret = iter_to_pipe(iter, pipe, buf_flag);
1310 pipe_unlock(pipe);
1311 if (ret > 0)
1312 wakeup_pipe_readers(pipe);
1313 return ret;
1314 }
1315
1316 static int vmsplice_type(struct fd f, int *type)
1317 {
1318 if (!f.file)
1319 return -EBADF;
1320 if (f.file->f_mode & FMODE_WRITE) {
1321 *type = WRITE;
1322 } else if (f.file->f_mode & FMODE_READ) {
1323 *type = READ;
1324 } else {
1325 fdput(f);
1326 return -EBADF;
1327 }
1328 return 0;
1329 }
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347 static long do_vmsplice(struct file *f, struct iov_iter *iter, unsigned int flags)
1348 {
1349 if (unlikely(flags & ~SPLICE_F_ALL))
1350 return -EINVAL;
1351
1352 if (!iov_iter_count(iter))
1353 return 0;
1354
1355 if (iov_iter_rw(iter) == WRITE)
1356 return vmsplice_to_pipe(f, iter, flags);
1357 else
1358 return vmsplice_to_user(f, iter, flags);
1359 }
1360
1361 SYSCALL_DEFINE4(vmsplice, int, fd, const struct iovec __user *, uiov,
1362 unsigned long, nr_segs, unsigned int, flags)
1363 {
1364 struct iovec iovstack[UIO_FASTIOV];
1365 struct iovec *iov = iovstack;
1366 struct iov_iter iter;
1367 ssize_t error;
1368 struct fd f;
1369 int type;
1370
1371 f = fdget(fd);
1372 error = vmsplice_type(f, &type);
1373 if (error)
1374 return error;
1375
1376 error = import_iovec(type, uiov, nr_segs,
1377 ARRAY_SIZE(iovstack), &iov, &iter);
1378 if (error >= 0) {
1379 error = do_vmsplice(f.file, &iter, flags);
1380 kfree(iov);
1381 }
1382 fdput(f);
1383 return error;
1384 }
1385
1386 #ifdef CONFIG_COMPAT
1387 COMPAT_SYSCALL_DEFINE4(vmsplice, int, fd, const struct compat_iovec __user *, iov32,
1388 unsigned int, nr_segs, unsigned int, flags)
1389 {
1390 struct iovec iovstack[UIO_FASTIOV];
1391 struct iovec *iov = iovstack;
1392 struct iov_iter iter;
1393 ssize_t error;
1394 struct fd f;
1395 int type;
1396
1397 f = fdget(fd);
1398 error = vmsplice_type(f, &type);
1399 if (error)
1400 return error;
1401
1402 error = compat_import_iovec(type, iov32, nr_segs,
1403 ARRAY_SIZE(iovstack), &iov, &iter);
1404 if (error >= 0) {
1405 error = do_vmsplice(f.file, &iter, flags);
1406 kfree(iov);
1407 }
1408 fdput(f);
1409 return error;
1410 }
1411 #endif
1412
1413 SYSCALL_DEFINE6(splice, int, fd_in, loff_t __user *, off_in,
1414 int, fd_out, loff_t __user *, off_out,
1415 size_t, len, unsigned int, flags)
1416 {
1417 struct fd in, out;
1418 long error;
1419
1420 if (unlikely(!len))
1421 return 0;
1422
1423 if (unlikely(flags & ~SPLICE_F_ALL))
1424 return -EINVAL;
1425
1426 error = -EBADF;
1427 in = fdget(fd_in);
1428 if (in.file) {
1429 if (in.file->f_mode & FMODE_READ) {
1430 out = fdget(fd_out);
1431 if (out.file) {
1432 if (out.file->f_mode & FMODE_WRITE)
1433 error = do_splice(in.file, off_in,
1434 out.file, off_out,
1435 len, flags);
1436 fdput(out);
1437 }
1438 }
1439 fdput(in);
1440 }
1441 return error;
1442 }
1443
1444
1445
1446
1447
1448 static int ipipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
1449 {
1450 int ret;
1451
1452
1453
1454
1455
1456 if (pipe->nrbufs)
1457 return 0;
1458
1459 ret = 0;
1460 pipe_lock(pipe);
1461
1462 while (!pipe->nrbufs) {
1463 if (signal_pending(current)) {
1464 ret = -ERESTARTSYS;
1465 break;
1466 }
1467 if (!pipe->writers)
1468 break;
1469 if (!pipe->waiting_writers) {
1470 if (flags & SPLICE_F_NONBLOCK) {
1471 ret = -EAGAIN;
1472 break;
1473 }
1474 }
1475 pipe_wait(pipe);
1476 }
1477
1478 pipe_unlock(pipe);
1479 return ret;
1480 }
1481
1482
1483
1484
1485
1486 static int opipe_prep(struct pipe_inode_info *pipe, unsigned int flags)
1487 {
1488 int ret;
1489
1490
1491
1492
1493
1494 if (pipe->nrbufs < pipe->buffers)
1495 return 0;
1496
1497 ret = 0;
1498 pipe_lock(pipe);
1499
1500 while (pipe->nrbufs >= pipe->buffers) {
1501 if (!pipe->readers) {
1502 send_sig(SIGPIPE, current, 0);
1503 ret = -EPIPE;
1504 break;
1505 }
1506 if (flags & SPLICE_F_NONBLOCK) {
1507 ret = -EAGAIN;
1508 break;
1509 }
1510 if (signal_pending(current)) {
1511 ret = -ERESTARTSYS;
1512 break;
1513 }
1514 pipe->waiting_writers++;
1515 pipe_wait(pipe);
1516 pipe->waiting_writers--;
1517 }
1518
1519 pipe_unlock(pipe);
1520 return ret;
1521 }
1522
1523
1524
1525
1526 static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
1527 struct pipe_inode_info *opipe,
1528 size_t len, unsigned int flags)
1529 {
1530 struct pipe_buffer *ibuf, *obuf;
1531 int ret = 0, nbuf;
1532 bool input_wakeup = false;
1533
1534
1535 retry:
1536 ret = ipipe_prep(ipipe, flags);
1537 if (ret)
1538 return ret;
1539
1540 ret = opipe_prep(opipe, flags);
1541 if (ret)
1542 return ret;
1543
1544
1545
1546
1547
1548
1549 pipe_double_lock(ipipe, opipe);
1550
1551 do {
1552 if (!opipe->readers) {
1553 send_sig(SIGPIPE, current, 0);
1554 if (!ret)
1555 ret = -EPIPE;
1556 break;
1557 }
1558
1559 if (!ipipe->nrbufs && !ipipe->writers)
1560 break;
1561
1562
1563
1564
1565
1566 if (!ipipe->nrbufs || opipe->nrbufs >= opipe->buffers) {
1567
1568 if (ret)
1569 break;
1570
1571 if (flags & SPLICE_F_NONBLOCK) {
1572 ret = -EAGAIN;
1573 break;
1574 }
1575
1576
1577
1578
1579
1580
1581 pipe_unlock(ipipe);
1582 pipe_unlock(opipe);
1583 goto retry;
1584 }
1585
1586 ibuf = ipipe->bufs + ipipe->curbuf;
1587 nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1);
1588 obuf = opipe->bufs + nbuf;
1589
1590 if (len >= ibuf->len) {
1591
1592
1593
1594 *obuf = *ibuf;
1595 ibuf->ops = NULL;
1596 opipe->nrbufs++;
1597 ipipe->curbuf = (ipipe->curbuf + 1) & (ipipe->buffers - 1);
1598 ipipe->nrbufs--;
1599 input_wakeup = true;
1600 } else {
1601
1602
1603
1604
1605 if (!pipe_buf_get(ipipe, ibuf)) {
1606 if (ret == 0)
1607 ret = -EFAULT;
1608 break;
1609 }
1610 *obuf = *ibuf;
1611
1612
1613
1614
1615
1616 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1617
1618 pipe_buf_mark_unmergeable(obuf);
1619
1620 obuf->len = len;
1621 opipe->nrbufs++;
1622 ibuf->offset += obuf->len;
1623 ibuf->len -= obuf->len;
1624 }
1625 ret += obuf->len;
1626 len -= obuf->len;
1627 } while (len);
1628
1629 pipe_unlock(ipipe);
1630 pipe_unlock(opipe);
1631
1632
1633
1634
1635 if (ret > 0)
1636 wakeup_pipe_readers(opipe);
1637
1638 if (input_wakeup)
1639 wakeup_pipe_writers(ipipe);
1640
1641 return ret;
1642 }
1643
1644
1645
1646
1647 static int link_pipe(struct pipe_inode_info *ipipe,
1648 struct pipe_inode_info *opipe,
1649 size_t len, unsigned int flags)
1650 {
1651 struct pipe_buffer *ibuf, *obuf;
1652 int ret = 0, i = 0, nbuf;
1653
1654
1655
1656
1657
1658
1659 pipe_double_lock(ipipe, opipe);
1660
1661 do {
1662 if (!opipe->readers) {
1663 send_sig(SIGPIPE, current, 0);
1664 if (!ret)
1665 ret = -EPIPE;
1666 break;
1667 }
1668
1669
1670
1671
1672
1673 if (i >= ipipe->nrbufs || opipe->nrbufs >= opipe->buffers)
1674 break;
1675
1676 ibuf = ipipe->bufs + ((ipipe->curbuf + i) & (ipipe->buffers-1));
1677 nbuf = (opipe->curbuf + opipe->nrbufs) & (opipe->buffers - 1);
1678
1679
1680
1681
1682
1683 if (!pipe_buf_get(ipipe, ibuf)) {
1684 if (ret == 0)
1685 ret = -EFAULT;
1686 break;
1687 }
1688
1689 obuf = opipe->bufs + nbuf;
1690 *obuf = *ibuf;
1691
1692
1693
1694
1695
1696 obuf->flags &= ~PIPE_BUF_FLAG_GIFT;
1697
1698 pipe_buf_mark_unmergeable(obuf);
1699
1700 if (obuf->len > len)
1701 obuf->len = len;
1702
1703 opipe->nrbufs++;
1704 ret += obuf->len;
1705 len -= obuf->len;
1706 i++;
1707 } while (len);
1708
1709
1710
1711
1712
1713 if (!ret && ipipe->waiting_writers && (flags & SPLICE_F_NONBLOCK))
1714 ret = -EAGAIN;
1715
1716 pipe_unlock(ipipe);
1717 pipe_unlock(opipe);
1718
1719
1720
1721
1722 if (ret > 0)
1723 wakeup_pipe_readers(opipe);
1724
1725 return ret;
1726 }
1727
1728
1729
1730
1731
1732
1733
1734 static long do_tee(struct file *in, struct file *out, size_t len,
1735 unsigned int flags)
1736 {
1737 struct pipe_inode_info *ipipe = get_pipe_info(in);
1738 struct pipe_inode_info *opipe = get_pipe_info(out);
1739 int ret = -EINVAL;
1740
1741
1742
1743
1744
1745 if (ipipe && opipe && ipipe != opipe) {
1746 if ((in->f_flags | out->f_flags) & O_NONBLOCK)
1747 flags |= SPLICE_F_NONBLOCK;
1748
1749
1750
1751
1752
1753 ret = ipipe_prep(ipipe, flags);
1754 if (!ret) {
1755 ret = opipe_prep(opipe, flags);
1756 if (!ret)
1757 ret = link_pipe(ipipe, opipe, len, flags);
1758 }
1759 }
1760
1761 return ret;
1762 }
1763
1764 SYSCALL_DEFINE4(tee, int, fdin, int, fdout, size_t, len, unsigned int, flags)
1765 {
1766 struct fd in;
1767 int error;
1768
1769 if (unlikely(flags & ~SPLICE_F_ALL))
1770 return -EINVAL;
1771
1772 if (unlikely(!len))
1773 return 0;
1774
1775 error = -EBADF;
1776 in = fdget(fdin);
1777 if (in.file) {
1778 if (in.file->f_mode & FMODE_READ) {
1779 struct fd out = fdget(fdout);
1780 if (out.file) {
1781 if (out.file->f_mode & FMODE_WRITE)
1782 error = do_tee(in.file, out.file,
1783 len, flags);
1784 fdput(out);
1785 }
1786 }
1787 fdput(in);
1788 }
1789
1790 return error;
1791 }