1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * linux/fs/read_write.c |
4 | * |
5 | * Copyright (C) 1991, 1992 Linus Torvalds |
6 | */ |
7 | |
8 | #include <linux/slab.h> |
9 | #include <linux/stat.h> |
10 | #include <linux/sched/xacct.h> |
11 | #include <linux/fcntl.h> |
12 | #include <linux/file.h> |
13 | #include <linux/uio.h> |
14 | #include <linux/fsnotify.h> |
15 | #include <linux/security.h> |
16 | #include <linux/export.h> |
17 | #include <linux/syscalls.h> |
18 | #include <linux/pagemap.h> |
19 | #include <linux/splice.h> |
20 | #include <linux/compat.h> |
21 | #include <linux/mount.h> |
22 | #include <linux/fs.h> |
23 | #include "internal.h" |
24 | |
25 | #include <linux/uaccess.h> |
26 | #include <asm/unistd.h> |
27 | |
28 | const struct file_operations generic_ro_fops = { |
29 | .llseek = generic_file_llseek, |
30 | .read_iter = generic_file_read_iter, |
31 | .mmap = generic_file_readonly_mmap, |
32 | .splice_read = generic_file_splice_read, |
33 | }; |
34 | |
35 | EXPORT_SYMBOL(generic_ro_fops); |
36 | |
37 | static inline bool unsigned_offsets(struct file *file) |
38 | { |
39 | return file->f_mode & FMODE_UNSIGNED_OFFSET; |
40 | } |
41 | |
42 | /** |
43 | * vfs_setpos - update the file offset for lseek |
44 | * @file: file structure in question |
45 | * @offset: file offset to seek to |
46 | * @maxsize: maximum file size |
47 | * |
48 | * This is a low-level filesystem helper for updating the file offset to |
49 | * the value specified by @offset if the given offset is valid and it is |
50 | * not equal to the current file offset. |
51 | * |
52 | * Return the specified offset on success and -EINVAL on invalid offset. |
53 | */ |
54 | loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize) |
55 | { |
56 | if (offset < 0 && !unsigned_offsets(file)) |
57 | return -EINVAL; |
58 | if (offset > maxsize) |
59 | return -EINVAL; |
60 | |
61 | if (offset != file->f_pos) { |
62 | file->f_pos = offset; |
63 | file->f_version = 0; |
64 | } |
65 | return offset; |
66 | } |
67 | EXPORT_SYMBOL(vfs_setpos); |
68 | |
69 | /** |
70 | * generic_file_llseek_size - generic llseek implementation for regular files |
71 | * @file: file structure to seek on |
72 | * @offset: file offset to seek to |
73 | * @whence: type of seek |
74 | * @size: max size of this file in file system |
75 | * @eof: offset used for SEEK_END position |
76 | * |
77 | * This is a variant of generic_file_llseek that allows passing in a custom |
78 | * maximum file size and a custom EOF position, for e.g. hashed directories |
79 | * |
80 | * Synchronization: |
81 | * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms) |
82 | * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes. |
83 | * read/writes behave like SEEK_SET against seeks. |
84 | */ |
85 | loff_t |
86 | generic_file_llseek_size(struct file *file, loff_t offset, int whence, |
87 | loff_t maxsize, loff_t eof) |
88 | { |
89 | switch (whence) { |
90 | case SEEK_END: |
91 | offset += eof; |
92 | break; |
93 | case SEEK_CUR: |
94 | /* |
95 | * Here we special-case the lseek(fd, 0, SEEK_CUR) |
96 | * position-querying operation. Avoid rewriting the "same" |
97 | * f_pos value back to the file because a concurrent read(), |
98 | * write() or lseek() might have altered it |
99 | */ |
100 | if (offset == 0) |
101 | return file->f_pos; |
102 | /* |
103 | * f_lock protects against read/modify/write race with other |
104 | * SEEK_CURs. Note that parallel writes and reads behave |
105 | * like SEEK_SET. |
106 | */ |
107 | spin_lock(&file->f_lock); |
108 | offset = vfs_setpos(file, file->f_pos + offset, maxsize); |
109 | spin_unlock(&file->f_lock); |
110 | return offset; |
111 | case SEEK_DATA: |
112 | /* |
113 | * In the generic case the entire file is data, so as long as |
114 | * offset isn't at the end of the file then the offset is data. |
115 | */ |
116 | if ((unsigned long long)offset >= eof) |
117 | return -ENXIO; |
118 | break; |
119 | case SEEK_HOLE: |
120 | /* |
121 | * There is a virtual hole at the end of the file, so as long as |
122 | * offset isn't i_size or larger, return i_size. |
123 | */ |
124 | if ((unsigned long long)offset >= eof) |
125 | return -ENXIO; |
126 | offset = eof; |
127 | break; |
128 | } |
129 | |
130 | return vfs_setpos(file, offset, maxsize); |
131 | } |
132 | EXPORT_SYMBOL(generic_file_llseek_size); |
133 | |
134 | /** |
135 | * generic_file_llseek - generic llseek implementation for regular files |
136 | * @file: file structure to seek on |
137 | * @offset: file offset to seek to |
138 | * @whence: type of seek |
139 | * |
140 | * This is a generic implemenation of ->llseek useable for all normal local |
141 | * filesystems. It just updates the file offset to the value specified by |
142 | * @offset and @whence. |
143 | */ |
144 | loff_t generic_file_llseek(struct file *file, loff_t offset, int whence) |
145 | { |
146 | struct inode *inode = file->f_mapping->host; |
147 | |
148 | return generic_file_llseek_size(file, offset, whence, |
149 | inode->i_sb->s_maxbytes, |
150 | i_size_read(inode)); |
151 | } |
152 | EXPORT_SYMBOL(generic_file_llseek); |
153 | |
154 | /** |
155 | * fixed_size_llseek - llseek implementation for fixed-sized devices |
156 | * @file: file structure to seek on |
157 | * @offset: file offset to seek to |
158 | * @whence: type of seek |
159 | * @size: size of the file |
160 | * |
161 | */ |
162 | loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size) |
163 | { |
164 | switch (whence) { |
165 | case SEEK_SET: case SEEK_CUR: case SEEK_END: |
166 | return generic_file_llseek_size(file, offset, whence, |
167 | size, size); |
168 | default: |
169 | return -EINVAL; |
170 | } |
171 | } |
172 | EXPORT_SYMBOL(fixed_size_llseek); |
173 | |
174 | /** |
175 | * no_seek_end_llseek - llseek implementation for fixed-sized devices |
176 | * @file: file structure to seek on |
177 | * @offset: file offset to seek to |
178 | * @whence: type of seek |
179 | * |
180 | */ |
181 | loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence) |
182 | { |
183 | switch (whence) { |
184 | case SEEK_SET: case SEEK_CUR: |
185 | return generic_file_llseek_size(file, offset, whence, |
186 | OFFSET_MAX, 0); |
187 | default: |
188 | return -EINVAL; |
189 | } |
190 | } |
191 | EXPORT_SYMBOL(no_seek_end_llseek); |
192 | |
193 | /** |
194 | * no_seek_end_llseek_size - llseek implementation for fixed-sized devices |
195 | * @file: file structure to seek on |
196 | * @offset: file offset to seek to |
197 | * @whence: type of seek |
198 | * @size: maximal offset allowed |
199 | * |
200 | */ |
201 | loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size) |
202 | { |
203 | switch (whence) { |
204 | case SEEK_SET: case SEEK_CUR: |
205 | return generic_file_llseek_size(file, offset, whence, |
206 | size, 0); |
207 | default: |
208 | return -EINVAL; |
209 | } |
210 | } |
211 | EXPORT_SYMBOL(no_seek_end_llseek_size); |
212 | |
213 | /** |
214 | * noop_llseek - No Operation Performed llseek implementation |
215 | * @file: file structure to seek on |
216 | * @offset: file offset to seek to |
217 | * @whence: type of seek |
218 | * |
219 | * This is an implementation of ->llseek useable for the rare special case when |
220 | * userspace expects the seek to succeed but the (device) file is actually not |
221 | * able to perform the seek. In this case you use noop_llseek() instead of |
222 | * falling back to the default implementation of ->llseek. |
223 | */ |
224 | loff_t noop_llseek(struct file *file, loff_t offset, int whence) |
225 | { |
226 | return file->f_pos; |
227 | } |
228 | EXPORT_SYMBOL(noop_llseek); |
229 | |
230 | loff_t default_llseek(struct file *file, loff_t offset, int whence) |
231 | { |
232 | struct inode *inode = file_inode(file); |
233 | loff_t retval; |
234 | |
235 | inode_lock(inode); |
236 | switch (whence) { |
237 | case SEEK_END: |
238 | offset += i_size_read(inode); |
239 | break; |
240 | case SEEK_CUR: |
241 | if (offset == 0) { |
242 | retval = file->f_pos; |
243 | goto out; |
244 | } |
245 | offset += file->f_pos; |
246 | break; |
247 | case SEEK_DATA: |
248 | /* |
249 | * In the generic case the entire file is data, so as |
250 | * long as offset isn't at the end of the file then the |
251 | * offset is data. |
252 | */ |
253 | if (offset >= inode->i_size) { |
254 | retval = -ENXIO; |
255 | goto out; |
256 | } |
257 | break; |
258 | case SEEK_HOLE: |
259 | /* |
260 | * There is a virtual hole at the end of the file, so |
261 | * as long as offset isn't i_size or larger, return |
262 | * i_size. |
263 | */ |
264 | if (offset >= inode->i_size) { |
265 | retval = -ENXIO; |
266 | goto out; |
267 | } |
268 | offset = inode->i_size; |
269 | break; |
270 | } |
271 | retval = -EINVAL; |
272 | if (offset >= 0 || unsigned_offsets(file)) { |
273 | if (offset != file->f_pos) { |
274 | file->f_pos = offset; |
275 | file->f_version = 0; |
276 | } |
277 | retval = offset; |
278 | } |
279 | out: |
280 | inode_unlock(inode); |
281 | return retval; |
282 | } |
283 | EXPORT_SYMBOL(default_llseek); |
284 | |
285 | loff_t vfs_llseek(struct file *file, loff_t offset, int whence) |
286 | { |
287 | if (!(file->f_mode & FMODE_LSEEK)) |
288 | return -ESPIPE; |
289 | return file->f_op->llseek(file, offset, whence); |
290 | } |
291 | EXPORT_SYMBOL(vfs_llseek); |
292 | |
293 | static off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence) |
294 | { |
295 | off_t retval; |
296 | struct fd f = fdget_pos(fd); |
297 | if (!f.file) |
298 | return -EBADF; |
299 | |
300 | retval = -EINVAL; |
301 | if (whence <= SEEK_MAX) { |
302 | loff_t res = vfs_llseek(f.file, offset, whence); |
303 | retval = res; |
304 | if (res != (loff_t)retval) |
305 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ |
306 | } |
307 | fdput_pos(f); |
308 | return retval; |
309 | } |
310 | |
311 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence) |
312 | { |
313 | return ksys_lseek(fd, offset, whence); |
314 | } |
315 | |
316 | #ifdef CONFIG_COMPAT |
317 | COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence) |
318 | { |
319 | return ksys_lseek(fd, offset, whence); |
320 | } |
321 | #endif |
322 | |
323 | #if !defined(CONFIG_64BIT) || defined(CONFIG_COMPAT) || \ |
324 | defined(__ARCH_WANT_SYS_LLSEEK) |
325 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, |
326 | unsigned long, offset_low, loff_t __user *, result, |
327 | unsigned int, whence) |
328 | { |
329 | int retval; |
330 | struct fd f = fdget_pos(fd); |
331 | loff_t offset; |
332 | |
333 | if (!f.file) |
334 | return -EBADF; |
335 | |
336 | retval = -EINVAL; |
337 | if (whence > SEEK_MAX) |
338 | goto out_putf; |
339 | |
340 | offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low, |
341 | whence); |
342 | |
343 | retval = (int)offset; |
344 | if (offset >= 0) { |
345 | retval = -EFAULT; |
346 | if (!copy_to_user(result, &offset, sizeof(offset))) |
347 | retval = 0; |
348 | } |
349 | out_putf: |
350 | fdput_pos(f); |
351 | return retval; |
352 | } |
353 | #endif |
354 | |
355 | int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count) |
356 | { |
357 | if (unlikely((ssize_t) count < 0)) |
358 | return -EINVAL; |
359 | |
360 | if (ppos) { |
361 | loff_t pos = *ppos; |
362 | |
363 | if (unlikely(pos < 0)) { |
364 | if (!unsigned_offsets(file)) |
365 | return -EINVAL; |
366 | if (count >= -pos) /* both values are in 0..LLONG_MAX */ |
367 | return -EOVERFLOW; |
368 | } else if (unlikely((loff_t) (pos + count) < 0)) { |
369 | if (!unsigned_offsets(file)) |
370 | return -EINVAL; |
371 | } |
372 | } |
373 | |
374 | return security_file_permission(file, |
375 | read_write == READ ? MAY_READ : MAY_WRITE); |
376 | } |
377 | EXPORT_SYMBOL(rw_verify_area); |
378 | |
379 | static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) |
380 | { |
381 | struct kiocb kiocb; |
382 | struct iov_iter iter; |
383 | ssize_t ret; |
384 | |
385 | init_sync_kiocb(&kiocb, filp); |
386 | kiocb.ki_pos = (ppos ? *ppos : 0); |
387 | iov_iter_ubuf(&iter, READ, buf, len); |
388 | |
389 | ret = call_read_iter(filp, &kiocb, &iter); |
390 | BUG_ON(ret == -EIOCBQUEUED); |
391 | if (ppos) |
392 | *ppos = kiocb.ki_pos; |
393 | return ret; |
394 | } |
395 | |
396 | static int warn_unsupported(struct file *file, const char *op) |
397 | { |
398 | pr_warn_ratelimited( |
399 | "kernel %s not supported for file %pD4 (pid: %d comm: %.20s)\n" , |
400 | op, file, current->pid, current->comm); |
401 | return -EINVAL; |
402 | } |
403 | |
404 | ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) |
405 | { |
406 | struct kvec iov = { |
407 | .iov_base = buf, |
408 | .iov_len = min_t(size_t, count, MAX_RW_COUNT), |
409 | }; |
410 | struct kiocb kiocb; |
411 | struct iov_iter iter; |
412 | ssize_t ret; |
413 | |
414 | if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ))) |
415 | return -EINVAL; |
416 | if (!(file->f_mode & FMODE_CAN_READ)) |
417 | return -EINVAL; |
418 | /* |
419 | * Also fail if ->read_iter and ->read are both wired up as that |
420 | * implies very convoluted semantics. |
421 | */ |
422 | if (unlikely(!file->f_op->read_iter || file->f_op->read)) |
423 | return warn_unsupported(file, "read" ); |
424 | |
425 | init_sync_kiocb(&kiocb, file); |
426 | kiocb.ki_pos = pos ? *pos : 0; |
427 | iov_iter_kvec(&iter, READ, &iov, 1, iov.iov_len); |
428 | ret = file->f_op->read_iter(&kiocb, &iter); |
429 | if (ret > 0) { |
430 | if (pos) |
431 | *pos = kiocb.ki_pos; |
432 | fsnotify_access(file); |
433 | add_rchar(current, ret); |
434 | } |
435 | inc_syscr(current); |
436 | return ret; |
437 | } |
438 | |
439 | ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) |
440 | { |
441 | ssize_t ret; |
442 | |
443 | ret = rw_verify_area(READ, file, pos, count); |
444 | if (ret) |
445 | return ret; |
446 | return __kernel_read(file, buf, count, pos); |
447 | } |
448 | EXPORT_SYMBOL(kernel_read); |
449 | |
450 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) |
451 | { |
452 | ssize_t ret; |
453 | |
454 | if (!(file->f_mode & FMODE_READ)) |
455 | return -EBADF; |
456 | if (!(file->f_mode & FMODE_CAN_READ)) |
457 | return -EINVAL; |
458 | if (unlikely(!access_ok(buf, count))) |
459 | return -EFAULT; |
460 | |
461 | ret = rw_verify_area(READ, file, pos, count); |
462 | if (ret) |
463 | return ret; |
464 | if (count > MAX_RW_COUNT) |
465 | count = MAX_RW_COUNT; |
466 | |
467 | if (file->f_op->read) |
468 | ret = file->f_op->read(file, buf, count, pos); |
469 | else if (file->f_op->read_iter) |
470 | ret = new_sync_read(file, buf, count, pos); |
471 | else |
472 | ret = -EINVAL; |
473 | if (ret > 0) { |
474 | fsnotify_access(file); |
475 | add_rchar(current, ret); |
476 | } |
477 | inc_syscr(current); |
478 | return ret; |
479 | } |
480 | |
481 | static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) |
482 | { |
483 | struct kiocb kiocb; |
484 | struct iov_iter iter; |
485 | ssize_t ret; |
486 | |
487 | init_sync_kiocb(&kiocb, filp); |
488 | kiocb.ki_pos = (ppos ? *ppos : 0); |
489 | iov_iter_ubuf(&iter, WRITE, (void __user *)buf, len); |
490 | |
491 | ret = call_write_iter(filp, &kiocb, &iter); |
492 | BUG_ON(ret == -EIOCBQUEUED); |
493 | if (ret > 0 && ppos) |
494 | *ppos = kiocb.ki_pos; |
495 | return ret; |
496 | } |
497 | |
498 | /* caller is responsible for file_start_write/file_end_write */ |
499 | ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos) |
500 | { |
501 | struct kvec iov = { |
502 | .iov_base = (void *)buf, |
503 | .iov_len = min_t(size_t, count, MAX_RW_COUNT), |
504 | }; |
505 | struct kiocb kiocb; |
506 | struct iov_iter iter; |
507 | ssize_t ret; |
508 | |
509 | if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE))) |
510 | return -EBADF; |
511 | if (!(file->f_mode & FMODE_CAN_WRITE)) |
512 | return -EINVAL; |
513 | /* |
514 | * Also fail if ->write_iter and ->write are both wired up as that |
515 | * implies very convoluted semantics. |
516 | */ |
517 | if (unlikely(!file->f_op->write_iter || file->f_op->write)) |
518 | return warn_unsupported(file, "write" ); |
519 | |
520 | init_sync_kiocb(&kiocb, file); |
521 | kiocb.ki_pos = pos ? *pos : 0; |
522 | iov_iter_kvec(&iter, WRITE, &iov, 1, iov.iov_len); |
523 | ret = file->f_op->write_iter(&kiocb, &iter); |
524 | if (ret > 0) { |
525 | if (pos) |
526 | *pos = kiocb.ki_pos; |
527 | fsnotify_modify(file); |
528 | add_wchar(current, ret); |
529 | } |
530 | inc_syscw(current); |
531 | return ret; |
532 | } |
533 | /* |
534 | * This "EXPORT_SYMBOL_GPL()" is more of a "EXPORT_SYMBOL_DONTUSE()", |
535 | * but autofs is one of the few internal kernel users that actually |
536 | * wants this _and_ can be built as a module. So we need to export |
537 | * this symbol for autofs, even though it really isn't appropriate |
538 | * for any other kernel modules. |
539 | */ |
540 | EXPORT_SYMBOL_GPL(__kernel_write); |
541 | |
542 | ssize_t kernel_write(struct file *file, const void *buf, size_t count, |
543 | loff_t *pos) |
544 | { |
545 | ssize_t ret; |
546 | |
547 | ret = rw_verify_area(WRITE, file, pos, count); |
548 | if (ret) |
549 | return ret; |
550 | |
551 | file_start_write(file); |
552 | ret = __kernel_write(file, buf, count, pos); |
553 | file_end_write(file); |
554 | return ret; |
555 | } |
556 | EXPORT_SYMBOL(kernel_write); |
557 | |
558 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
559 | { |
560 | ssize_t ret; |
561 | |
562 | if (!(file->f_mode & FMODE_WRITE)) |
563 | return -EBADF; |
564 | if (!(file->f_mode & FMODE_CAN_WRITE)) |
565 | return -EINVAL; |
566 | if (unlikely(!access_ok(buf, count))) |
567 | return -EFAULT; |
568 | |
569 | ret = rw_verify_area(WRITE, file, pos, count); |
570 | if (ret) |
571 | return ret; |
572 | if (count > MAX_RW_COUNT) |
573 | count = MAX_RW_COUNT; |
574 | file_start_write(file); |
575 | if (file->f_op->write) |
576 | ret = file->f_op->write(file, buf, count, pos); |
577 | else if (file->f_op->write_iter) |
578 | ret = new_sync_write(file, buf, count, pos); |
579 | else |
580 | ret = -EINVAL; |
581 | if (ret > 0) { |
582 | fsnotify_modify(file); |
583 | add_wchar(current, ret); |
584 | } |
585 | inc_syscw(current); |
586 | file_end_write(file); |
587 | return ret; |
588 | } |
589 | |
590 | /* file_ppos returns &file->f_pos or NULL if file is stream */ |
591 | static inline loff_t *file_ppos(struct file *file) |
592 | { |
593 | return file->f_mode & FMODE_STREAM ? NULL : &file->f_pos; |
594 | } |
595 | |
596 | ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count) |
597 | { |
598 | struct fd f = fdget_pos(fd); |
599 | ssize_t ret = -EBADF; |
600 | |
601 | if (f.file) { |
602 | loff_t pos, *ppos = file_ppos(f.file); |
603 | if (ppos) { |
604 | pos = *ppos; |
605 | ppos = &pos; |
606 | } |
607 | ret = vfs_read(f.file, buf, count, ppos); |
608 | if (ret >= 0 && ppos) |
609 | f.file->f_pos = pos; |
610 | fdput_pos(f); |
611 | } |
612 | return ret; |
613 | } |
614 | |
615 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) |
616 | { |
617 | return ksys_read(fd, buf, count); |
618 | } |
619 | |
620 | ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count) |
621 | { |
622 | struct fd f = fdget_pos(fd); |
623 | ssize_t ret = -EBADF; |
624 | |
625 | if (f.file) { |
626 | loff_t pos, *ppos = file_ppos(f.file); |
627 | if (ppos) { |
628 | pos = *ppos; |
629 | ppos = &pos; |
630 | } |
631 | ret = vfs_write(f.file, buf, count, ppos); |
632 | if (ret >= 0 && ppos) |
633 | f.file->f_pos = pos; |
634 | fdput_pos(f); |
635 | } |
636 | |
637 | return ret; |
638 | } |
639 | |
640 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, |
641 | size_t, count) |
642 | { |
643 | return ksys_write(fd, buf, count); |
644 | } |
645 | |
646 | ssize_t ksys_pread64(unsigned int fd, char __user *buf, size_t count, |
647 | loff_t pos) |
648 | { |
649 | struct fd f; |
650 | ssize_t ret = -EBADF; |
651 | |
652 | if (pos < 0) |
653 | return -EINVAL; |
654 | |
655 | f = fdget(fd); |
656 | if (f.file) { |
657 | ret = -ESPIPE; |
658 | if (f.file->f_mode & FMODE_PREAD) |
659 | ret = vfs_read(f.file, buf, count, &pos); |
660 | fdput(f); |
661 | } |
662 | |
663 | return ret; |
664 | } |
665 | |
666 | SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf, |
667 | size_t, count, loff_t, pos) |
668 | { |
669 | return ksys_pread64(fd, buf, count, pos); |
670 | } |
671 | |
672 | #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PREAD64) |
673 | COMPAT_SYSCALL_DEFINE5(pread64, unsigned int, fd, char __user *, buf, |
674 | size_t, count, compat_arg_u64_dual(pos)) |
675 | { |
676 | return ksys_pread64(fd, buf, count, compat_arg_u64_glue(pos)); |
677 | } |
678 | #endif |
679 | |
680 | ssize_t ksys_pwrite64(unsigned int fd, const char __user *buf, |
681 | size_t count, loff_t pos) |
682 | { |
683 | struct fd f; |
684 | ssize_t ret = -EBADF; |
685 | |
686 | if (pos < 0) |
687 | return -EINVAL; |
688 | |
689 | f = fdget(fd); |
690 | if (f.file) { |
691 | ret = -ESPIPE; |
692 | if (f.file->f_mode & FMODE_PWRITE) |
693 | ret = vfs_write(f.file, buf, count, &pos); |
694 | fdput(f); |
695 | } |
696 | |
697 | return ret; |
698 | } |
699 | |
700 | SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf, |
701 | size_t, count, loff_t, pos) |
702 | { |
703 | return ksys_pwrite64(fd, buf, count, pos); |
704 | } |
705 | |
706 | #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PWRITE64) |
707 | COMPAT_SYSCALL_DEFINE5(pwrite64, unsigned int, fd, const char __user *, buf, |
708 | size_t, count, compat_arg_u64_dual(pos)) |
709 | { |
710 | return ksys_pwrite64(fd, buf, count, compat_arg_u64_glue(pos)); |
711 | } |
712 | #endif |
713 | |
714 | static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter, |
715 | loff_t *ppos, int type, rwf_t flags) |
716 | { |
717 | struct kiocb kiocb; |
718 | ssize_t ret; |
719 | |
720 | init_sync_kiocb(&kiocb, filp); |
721 | ret = kiocb_set_rw_flags(&kiocb, flags); |
722 | if (ret) |
723 | return ret; |
724 | kiocb.ki_pos = (ppos ? *ppos : 0); |
725 | |
726 | if (type == READ) |
727 | ret = call_read_iter(filp, &kiocb, iter); |
728 | else |
729 | ret = call_write_iter(filp, &kiocb, iter); |
730 | BUG_ON(ret == -EIOCBQUEUED); |
731 | if (ppos) |
732 | *ppos = kiocb.ki_pos; |
733 | return ret; |
734 | } |
735 | |
736 | /* Do it by hand, with file-ops */ |
737 | static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter, |
738 | loff_t *ppos, int type, rwf_t flags) |
739 | { |
740 | ssize_t ret = 0; |
741 | |
742 | if (flags & ~RWF_HIPRI) |
743 | return -EOPNOTSUPP; |
744 | |
745 | while (iov_iter_count(iter)) { |
746 | struct iovec iovec = iov_iter_iovec(iter); |
747 | ssize_t nr; |
748 | |
749 | if (type == READ) { |
750 | nr = filp->f_op->read(filp, iovec.iov_base, |
751 | iovec.iov_len, ppos); |
752 | } else { |
753 | nr = filp->f_op->write(filp, iovec.iov_base, |
754 | iovec.iov_len, ppos); |
755 | } |
756 | |
757 | if (nr < 0) { |
758 | if (!ret) |
759 | ret = nr; |
760 | break; |
761 | } |
762 | ret += nr; |
763 | if (nr != iovec.iov_len) |
764 | break; |
765 | iov_iter_advance(iter, nr); |
766 | } |
767 | |
768 | return ret; |
769 | } |
770 | |
771 | static ssize_t do_iter_read(struct file *file, struct iov_iter *iter, |
772 | loff_t *pos, rwf_t flags) |
773 | { |
774 | size_t tot_len; |
775 | ssize_t ret = 0; |
776 | |
777 | if (!(file->f_mode & FMODE_READ)) |
778 | return -EBADF; |
779 | if (!(file->f_mode & FMODE_CAN_READ)) |
780 | return -EINVAL; |
781 | |
782 | tot_len = iov_iter_count(iter); |
783 | if (!tot_len) |
784 | goto out; |
785 | ret = rw_verify_area(READ, file, pos, tot_len); |
786 | if (ret < 0) |
787 | return ret; |
788 | |
789 | if (file->f_op->read_iter) |
790 | ret = do_iter_readv_writev(file, iter, pos, READ, flags); |
791 | else |
792 | ret = do_loop_readv_writev(file, iter, pos, READ, flags); |
793 | out: |
794 | if (ret >= 0) |
795 | fsnotify_access(file); |
796 | return ret; |
797 | } |
798 | |
799 | ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb, |
800 | struct iov_iter *iter) |
801 | { |
802 | size_t tot_len; |
803 | ssize_t ret = 0; |
804 | |
805 | if (!file->f_op->read_iter) |
806 | return -EINVAL; |
807 | if (!(file->f_mode & FMODE_READ)) |
808 | return -EBADF; |
809 | if (!(file->f_mode & FMODE_CAN_READ)) |
810 | return -EINVAL; |
811 | |
812 | tot_len = iov_iter_count(iter); |
813 | if (!tot_len) |
814 | goto out; |
815 | ret = rw_verify_area(READ, file, &iocb->ki_pos, tot_len); |
816 | if (ret < 0) |
817 | return ret; |
818 | |
819 | ret = call_read_iter(file, iocb, iter); |
820 | out: |
821 | if (ret >= 0) |
822 | fsnotify_access(file); |
823 | return ret; |
824 | } |
825 | EXPORT_SYMBOL(vfs_iocb_iter_read); |
826 | |
827 | ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos, |
828 | rwf_t flags) |
829 | { |
830 | if (!file->f_op->read_iter) |
831 | return -EINVAL; |
832 | return do_iter_read(file, iter, ppos, flags); |
833 | } |
834 | EXPORT_SYMBOL(vfs_iter_read); |
835 | |
836 | static ssize_t do_iter_write(struct file *file, struct iov_iter *iter, |
837 | loff_t *pos, rwf_t flags) |
838 | { |
839 | size_t tot_len; |
840 | ssize_t ret = 0; |
841 | |
842 | if (!(file->f_mode & FMODE_WRITE)) |
843 | return -EBADF; |
844 | if (!(file->f_mode & FMODE_CAN_WRITE)) |
845 | return -EINVAL; |
846 | |
847 | tot_len = iov_iter_count(iter); |
848 | if (!tot_len) |
849 | return 0; |
850 | ret = rw_verify_area(WRITE, file, pos, tot_len); |
851 | if (ret < 0) |
852 | return ret; |
853 | |
854 | if (file->f_op->write_iter) |
855 | ret = do_iter_readv_writev(file, iter, pos, WRITE, flags); |
856 | else |
857 | ret = do_loop_readv_writev(file, iter, pos, WRITE, flags); |
858 | if (ret > 0) |
859 | fsnotify_modify(file); |
860 | return ret; |
861 | } |
862 | |
863 | ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb, |
864 | struct iov_iter *iter) |
865 | { |
866 | size_t tot_len; |
867 | ssize_t ret = 0; |
868 | |
869 | if (!file->f_op->write_iter) |
870 | return -EINVAL; |
871 | if (!(file->f_mode & FMODE_WRITE)) |
872 | return -EBADF; |
873 | if (!(file->f_mode & FMODE_CAN_WRITE)) |
874 | return -EINVAL; |
875 | |
876 | tot_len = iov_iter_count(iter); |
877 | if (!tot_len) |
878 | return 0; |
879 | ret = rw_verify_area(WRITE, file, &iocb->ki_pos, tot_len); |
880 | if (ret < 0) |
881 | return ret; |
882 | |
883 | ret = call_write_iter(file, iocb, iter); |
884 | if (ret > 0) |
885 | fsnotify_modify(file); |
886 | |
887 | return ret; |
888 | } |
889 | EXPORT_SYMBOL(vfs_iocb_iter_write); |
890 | |
891 | ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos, |
892 | rwf_t flags) |
893 | { |
894 | if (!file->f_op->write_iter) |
895 | return -EINVAL; |
896 | return do_iter_write(file, iter, ppos, flags); |
897 | } |
898 | EXPORT_SYMBOL(vfs_iter_write); |
899 | |
900 | static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, |
901 | unsigned long vlen, loff_t *pos, rwf_t flags) |
902 | { |
903 | struct iovec iovstack[UIO_FASTIOV]; |
904 | struct iovec *iov = iovstack; |
905 | struct iov_iter iter; |
906 | ssize_t ret; |
907 | |
908 | ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); |
909 | if (ret >= 0) { |
910 | ret = do_iter_read(file, &iter, pos, flags); |
911 | kfree(iov); |
912 | } |
913 | |
914 | return ret; |
915 | } |
916 | |
917 | static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, |
918 | unsigned long vlen, loff_t *pos, rwf_t flags) |
919 | { |
920 | struct iovec iovstack[UIO_FASTIOV]; |
921 | struct iovec *iov = iovstack; |
922 | struct iov_iter iter; |
923 | ssize_t ret; |
924 | |
925 | ret = import_iovec(WRITE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); |
926 | if (ret >= 0) { |
927 | file_start_write(file); |
928 | ret = do_iter_write(file, &iter, pos, flags); |
929 | file_end_write(file); |
930 | kfree(iov); |
931 | } |
932 | return ret; |
933 | } |
934 | |
935 | static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec, |
936 | unsigned long vlen, rwf_t flags) |
937 | { |
938 | struct fd f = fdget_pos(fd); |
939 | ssize_t ret = -EBADF; |
940 | |
941 | if (f.file) { |
942 | loff_t pos, *ppos = file_ppos(f.file); |
943 | if (ppos) { |
944 | pos = *ppos; |
945 | ppos = &pos; |
946 | } |
947 | ret = vfs_readv(f.file, vec, vlen, ppos, flags); |
948 | if (ret >= 0 && ppos) |
949 | f.file->f_pos = pos; |
950 | fdput_pos(f); |
951 | } |
952 | |
953 | if (ret > 0) |
954 | add_rchar(current, ret); |
955 | inc_syscr(current); |
956 | return ret; |
957 | } |
958 | |
959 | static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec, |
960 | unsigned long vlen, rwf_t flags) |
961 | { |
962 | struct fd f = fdget_pos(fd); |
963 | ssize_t ret = -EBADF; |
964 | |
965 | if (f.file) { |
966 | loff_t pos, *ppos = file_ppos(f.file); |
967 | if (ppos) { |
968 | pos = *ppos; |
969 | ppos = &pos; |
970 | } |
971 | ret = vfs_writev(f.file, vec, vlen, ppos, flags); |
972 | if (ret >= 0 && ppos) |
973 | f.file->f_pos = pos; |
974 | fdput_pos(f); |
975 | } |
976 | |
977 | if (ret > 0) |
978 | add_wchar(current, ret); |
979 | inc_syscw(current); |
980 | return ret; |
981 | } |
982 | |
983 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) |
984 | { |
985 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) |
986 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; |
987 | } |
988 | |
989 | static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec, |
990 | unsigned long vlen, loff_t pos, rwf_t flags) |
991 | { |
992 | struct fd f; |
993 | ssize_t ret = -EBADF; |
994 | |
995 | if (pos < 0) |
996 | return -EINVAL; |
997 | |
998 | f = fdget(fd); |
999 | if (f.file) { |
1000 | ret = -ESPIPE; |
1001 | if (f.file->f_mode & FMODE_PREAD) |
1002 | ret = vfs_readv(f.file, vec, vlen, &pos, flags); |
1003 | fdput(f); |
1004 | } |
1005 | |
1006 | if (ret > 0) |
1007 | add_rchar(current, ret); |
1008 | inc_syscr(current); |
1009 | return ret; |
1010 | } |
1011 | |
1012 | static ssize_t do_pwritev(unsigned long fd, const struct iovec __user *vec, |
1013 | unsigned long vlen, loff_t pos, rwf_t flags) |
1014 | { |
1015 | struct fd f; |
1016 | ssize_t ret = -EBADF; |
1017 | |
1018 | if (pos < 0) |
1019 | return -EINVAL; |
1020 | |
1021 | f = fdget(fd); |
1022 | if (f.file) { |
1023 | ret = -ESPIPE; |
1024 | if (f.file->f_mode & FMODE_PWRITE) |
1025 | ret = vfs_writev(f.file, vec, vlen, &pos, flags); |
1026 | fdput(f); |
1027 | } |
1028 | |
1029 | if (ret > 0) |
1030 | add_wchar(current, ret); |
1031 | inc_syscw(current); |
1032 | return ret; |
1033 | } |
1034 | |
1035 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, |
1036 | unsigned long, vlen) |
1037 | { |
1038 | return do_readv(fd, vec, vlen, 0); |
1039 | } |
1040 | |
1041 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, |
1042 | unsigned long, vlen) |
1043 | { |
1044 | return do_writev(fd, vec, vlen, 0); |
1045 | } |
1046 | |
1047 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, |
1048 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
1049 | { |
1050 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
1051 | |
1052 | return do_preadv(fd, vec, vlen, pos, 0); |
1053 | } |
1054 | |
1055 | SYSCALL_DEFINE6(preadv2, unsigned long, fd, const struct iovec __user *, vec, |
1056 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h, |
1057 | rwf_t, flags) |
1058 | { |
1059 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
1060 | |
1061 | if (pos == -1) |
1062 | return do_readv(fd, vec, vlen, flags); |
1063 | |
1064 | return do_preadv(fd, vec, vlen, pos, flags); |
1065 | } |
1066 | |
1067 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, |
1068 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
1069 | { |
1070 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
1071 | |
1072 | return do_pwritev(fd, vec, vlen, pos, 0); |
1073 | } |
1074 | |
1075 | SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec, |
1076 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h, |
1077 | rwf_t, flags) |
1078 | { |
1079 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
1080 | |
1081 | if (pos == -1) |
1082 | return do_writev(fd, vec, vlen, flags); |
1083 | |
1084 | return do_pwritev(fd, vec, vlen, pos, flags); |
1085 | } |
1086 | |
1087 | /* |
1088 | * Various compat syscalls. Note that they all pretend to take a native |
1089 | * iovec - import_iovec will properly treat those as compat_iovecs based on |
1090 | * in_compat_syscall(). |
1091 | */ |
1092 | #ifdef CONFIG_COMPAT |
1093 | #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64 |
1094 | COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd, |
1095 | const struct iovec __user *, vec, |
1096 | unsigned long, vlen, loff_t, pos) |
1097 | { |
1098 | return do_preadv(fd, vec, vlen, pos, 0); |
1099 | } |
1100 | #endif |
1101 | |
1102 | COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd, |
1103 | const struct iovec __user *, vec, |
1104 | compat_ulong_t, vlen, u32, pos_low, u32, pos_high) |
1105 | { |
1106 | loff_t pos = ((loff_t)pos_high << 32) | pos_low; |
1107 | |
1108 | return do_preadv(fd, vec, vlen, pos, 0); |
1109 | } |
1110 | |
1111 | #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64V2 |
1112 | COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd, |
1113 | const struct iovec __user *, vec, |
1114 | unsigned long, vlen, loff_t, pos, rwf_t, flags) |
1115 | { |
1116 | if (pos == -1) |
1117 | return do_readv(fd, vec, vlen, flags); |
1118 | return do_preadv(fd, vec, vlen, pos, flags); |
1119 | } |
1120 | #endif |
1121 | |
1122 | COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd, |
1123 | const struct iovec __user *, vec, |
1124 | compat_ulong_t, vlen, u32, pos_low, u32, pos_high, |
1125 | rwf_t, flags) |
1126 | { |
1127 | loff_t pos = ((loff_t)pos_high << 32) | pos_low; |
1128 | |
1129 | if (pos == -1) |
1130 | return do_readv(fd, vec, vlen, flags); |
1131 | return do_preadv(fd, vec, vlen, pos, flags); |
1132 | } |
1133 | |
1134 | #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64 |
1135 | COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd, |
1136 | const struct iovec __user *, vec, |
1137 | unsigned long, vlen, loff_t, pos) |
1138 | { |
1139 | return do_pwritev(fd, vec, vlen, pos, 0); |
1140 | } |
1141 | #endif |
1142 | |
1143 | COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd, |
1144 | const struct iovec __user *,vec, |
1145 | compat_ulong_t, vlen, u32, pos_low, u32, pos_high) |
1146 | { |
1147 | loff_t pos = ((loff_t)pos_high << 32) | pos_low; |
1148 | |
1149 | return do_pwritev(fd, vec, vlen, pos, 0); |
1150 | } |
1151 | |
1152 | #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64V2 |
1153 | COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd, |
1154 | const struct iovec __user *, vec, |
1155 | unsigned long, vlen, loff_t, pos, rwf_t, flags) |
1156 | { |
1157 | if (pos == -1) |
1158 | return do_writev(fd, vec, vlen, flags); |
1159 | return do_pwritev(fd, vec, vlen, pos, flags); |
1160 | } |
1161 | #endif |
1162 | |
1163 | COMPAT_SYSCALL_DEFINE6(pwritev2, compat_ulong_t, fd, |
1164 | const struct iovec __user *,vec, |
1165 | compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags) |
1166 | { |
1167 | loff_t pos = ((loff_t)pos_high << 32) | pos_low; |
1168 | |
1169 | if (pos == -1) |
1170 | return do_writev(fd, vec, vlen, flags); |
1171 | return do_pwritev(fd, vec, vlen, pos, flags); |
1172 | } |
1173 | #endif /* CONFIG_COMPAT */ |
1174 | |
1175 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, |
1176 | size_t count, loff_t max) |
1177 | { |
1178 | struct fd in, out; |
1179 | struct inode *in_inode, *out_inode; |
1180 | struct pipe_inode_info *opipe; |
1181 | loff_t pos; |
1182 | loff_t out_pos; |
1183 | ssize_t retval; |
1184 | int fl; |
1185 | |
1186 | /* |
1187 | * Get input file, and verify that it is ok.. |
1188 | */ |
1189 | retval = -EBADF; |
1190 | in = fdget(in_fd); |
1191 | if (!in.file) |
1192 | goto out; |
1193 | if (!(in.file->f_mode & FMODE_READ)) |
1194 | goto fput_in; |
1195 | retval = -ESPIPE; |
1196 | if (!ppos) { |
1197 | pos = in.file->f_pos; |
1198 | } else { |
1199 | pos = *ppos; |
1200 | if (!(in.file->f_mode & FMODE_PREAD)) |
1201 | goto fput_in; |
1202 | } |
1203 | retval = rw_verify_area(READ, in.file, &pos, count); |
1204 | if (retval < 0) |
1205 | goto fput_in; |
1206 | if (count > MAX_RW_COUNT) |
1207 | count = MAX_RW_COUNT; |
1208 | |
1209 | /* |
1210 | * Get output file, and verify that it is ok.. |
1211 | */ |
1212 | retval = -EBADF; |
1213 | out = fdget(out_fd); |
1214 | if (!out.file) |
1215 | goto fput_in; |
1216 | if (!(out.file->f_mode & FMODE_WRITE)) |
1217 | goto fput_out; |
1218 | in_inode = file_inode(in.file); |
1219 | out_inode = file_inode(out.file); |
1220 | out_pos = out.file->f_pos; |
1221 | |
1222 | if (!max) |
1223 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); |
1224 | |
1225 | if (unlikely(pos + count > max)) { |
1226 | retval = -EOVERFLOW; |
1227 | if (pos >= max) |
1228 | goto fput_out; |
1229 | count = max - pos; |
1230 | } |
1231 | |
1232 | fl = 0; |
1233 | #if 0 |
1234 | /* |
1235 | * We need to debate whether we can enable this or not. The |
1236 | * man page documents EAGAIN return for the output at least, |
1237 | * and the application is arguably buggy if it doesn't expect |
1238 | * EAGAIN on a non-blocking file descriptor. |
1239 | */ |
1240 | if (in.file->f_flags & O_NONBLOCK) |
1241 | fl = SPLICE_F_NONBLOCK; |
1242 | #endif |
1243 | opipe = get_pipe_info(out.file, true); |
1244 | if (!opipe) { |
1245 | retval = rw_verify_area(WRITE, out.file, &out_pos, count); |
1246 | if (retval < 0) |
1247 | goto fput_out; |
1248 | file_start_write(out.file); |
1249 | retval = do_splice_direct(in.file, &pos, out.file, &out_pos, |
1250 | count, fl); |
1251 | file_end_write(out.file); |
1252 | } else { |
1253 | if (out.file->f_flags & O_NONBLOCK) |
1254 | fl |= SPLICE_F_NONBLOCK; |
1255 | |
1256 | retval = splice_file_to_pipe(in.file, opipe, &pos, count, fl); |
1257 | } |
1258 | |
1259 | if (retval > 0) { |
1260 | add_rchar(current, retval); |
1261 | add_wchar(current, retval); |
1262 | fsnotify_access(in.file); |
1263 | fsnotify_modify(out.file); |
1264 | out.file->f_pos = out_pos; |
1265 | if (ppos) |
1266 | *ppos = pos; |
1267 | else |
1268 | in.file->f_pos = pos; |
1269 | } |
1270 | |
1271 | inc_syscr(current); |
1272 | inc_syscw(current); |
1273 | if (pos > max) |
1274 | retval = -EOVERFLOW; |
1275 | |
1276 | fput_out: |
1277 | fdput(out); |
1278 | fput_in: |
1279 | fdput(in); |
1280 | out: |
1281 | return retval; |
1282 | } |
1283 | |
1284 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) |
1285 | { |
1286 | loff_t pos; |
1287 | off_t off; |
1288 | ssize_t ret; |
1289 | |
1290 | if (offset) { |
1291 | if (unlikely(get_user(off, offset))) |
1292 | return -EFAULT; |
1293 | pos = off; |
1294 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); |
1295 | if (unlikely(put_user(pos, offset))) |
1296 | return -EFAULT; |
1297 | return ret; |
1298 | } |
1299 | |
1300 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
1301 | } |
1302 | |
1303 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) |
1304 | { |
1305 | loff_t pos; |
1306 | ssize_t ret; |
1307 | |
1308 | if (offset) { |
1309 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) |
1310 | return -EFAULT; |
1311 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); |
1312 | if (unlikely(put_user(pos, offset))) |
1313 | return -EFAULT; |
1314 | return ret; |
1315 | } |
1316 | |
1317 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
1318 | } |
1319 | |
1320 | #ifdef CONFIG_COMPAT |
1321 | COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, |
1322 | compat_off_t __user *, offset, compat_size_t, count) |
1323 | { |
1324 | loff_t pos; |
1325 | off_t off; |
1326 | ssize_t ret; |
1327 | |
1328 | if (offset) { |
1329 | if (unlikely(get_user(off, offset))) |
1330 | return -EFAULT; |
1331 | pos = off; |
1332 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); |
1333 | if (unlikely(put_user(pos, offset))) |
1334 | return -EFAULT; |
1335 | return ret; |
1336 | } |
1337 | |
1338 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
1339 | } |
1340 | |
1341 | COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, |
1342 | compat_loff_t __user *, offset, compat_size_t, count) |
1343 | { |
1344 | loff_t pos; |
1345 | ssize_t ret; |
1346 | |
1347 | if (offset) { |
1348 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) |
1349 | return -EFAULT; |
1350 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); |
1351 | if (unlikely(put_user(pos, offset))) |
1352 | return -EFAULT; |
1353 | return ret; |
1354 | } |
1355 | |
1356 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
1357 | } |
1358 | #endif |
1359 | |
1360 | /** |
1361 | * generic_copy_file_range - copy data between two files |
1362 | * @file_in: file structure to read from |
1363 | * @pos_in: file offset to read from |
1364 | * @file_out: file structure to write data to |
1365 | * @pos_out: file offset to write data to |
1366 | * @len: amount of data to copy |
1367 | * @flags: copy flags |
1368 | * |
1369 | * This is a generic filesystem helper to copy data from one file to another. |
1370 | * It has no constraints on the source or destination file owners - the files |
1371 | * can belong to different superblocks and different filesystem types. Short |
1372 | * copies are allowed. |
1373 | * |
1374 | * This should be called from the @file_out filesystem, as per the |
1375 | * ->copy_file_range() method. |
1376 | * |
1377 | * Returns the number of bytes copied or a negative error indicating the |
1378 | * failure. |
1379 | */ |
1380 | |
1381 | ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, |
1382 | struct file *file_out, loff_t pos_out, |
1383 | size_t len, unsigned int flags) |
1384 | { |
1385 | return do_splice_direct(file_in, &pos_in, file_out, &pos_out, |
1386 | len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0); |
1387 | } |
1388 | EXPORT_SYMBOL(generic_copy_file_range); |
1389 | |
1390 | /* |
1391 | * Performs necessary checks before doing a file copy |
1392 | * |
1393 | * Can adjust amount of bytes to copy via @req_count argument. |
1394 | * Returns appropriate error code that caller should return or |
1395 | * zero in case the copy should be allowed. |
1396 | */ |
1397 | static int generic_copy_file_checks(struct file *file_in, loff_t pos_in, |
1398 | struct file *file_out, loff_t pos_out, |
1399 | size_t *req_count, unsigned int flags) |
1400 | { |
1401 | struct inode *inode_in = file_inode(file_in); |
1402 | struct inode *inode_out = file_inode(file_out); |
1403 | uint64_t count = *req_count; |
1404 | loff_t size_in; |
1405 | int ret; |
1406 | |
1407 | ret = generic_file_rw_checks(file_in, file_out); |
1408 | if (ret) |
1409 | return ret; |
1410 | |
1411 | /* |
1412 | * We allow some filesystems to handle cross sb copy, but passing |
1413 | * a file of the wrong filesystem type to filesystem driver can result |
1414 | * in an attempt to dereference the wrong type of ->private_data, so |
1415 | * avoid doing that until we really have a good reason. |
1416 | * |
1417 | * nfs and cifs define several different file_system_type structures |
1418 | * and several different sets of file_operations, but they all end up |
1419 | * using the same ->copy_file_range() function pointer. |
1420 | */ |
1421 | if (file_out->f_op->copy_file_range) { |
1422 | if (file_in->f_op->copy_file_range != |
1423 | file_out->f_op->copy_file_range) |
1424 | return -EXDEV; |
1425 | } else if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) { |
1426 | return -EXDEV; |
1427 | } |
1428 | |
1429 | /* Don't touch certain kinds of inodes */ |
1430 | if (IS_IMMUTABLE(inode_out)) |
1431 | return -EPERM; |
1432 | |
1433 | if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out)) |
1434 | return -ETXTBSY; |
1435 | |
1436 | /* Ensure offsets don't wrap. */ |
1437 | if (pos_in + count < pos_in || pos_out + count < pos_out) |
1438 | return -EOVERFLOW; |
1439 | |
1440 | /* Shorten the copy to EOF */ |
1441 | size_in = i_size_read(inode_in); |
1442 | if (pos_in >= size_in) |
1443 | count = 0; |
1444 | else |
1445 | count = min(count, size_in - (uint64_t)pos_in); |
1446 | |
1447 | ret = generic_write_check_limits(file_out, pos_out, &count); |
1448 | if (ret) |
1449 | return ret; |
1450 | |
1451 | /* Don't allow overlapped copying within the same file. */ |
1452 | if (inode_in == inode_out && |
1453 | pos_out + count > pos_in && |
1454 | pos_out < pos_in + count) |
1455 | return -EINVAL; |
1456 | |
1457 | *req_count = count; |
1458 | return 0; |
1459 | } |
1460 | |
1461 | /* |
1462 | * copy_file_range() differs from regular file read and write in that it |
1463 | * specifically allows return partial success. When it does so is up to |
1464 | * the copy_file_range method. |
1465 | */ |
1466 | ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, |
1467 | struct file *file_out, loff_t pos_out, |
1468 | size_t len, unsigned int flags) |
1469 | { |
1470 | ssize_t ret; |
1471 | |
1472 | if (flags != 0) |
1473 | return -EINVAL; |
1474 | |
1475 | ret = generic_copy_file_checks(file_in, pos_in, file_out, pos_out, &len, |
1476 | flags); |
1477 | if (unlikely(ret)) |
1478 | return ret; |
1479 | |
1480 | ret = rw_verify_area(READ, file_in, &pos_in, len); |
1481 | if (unlikely(ret)) |
1482 | return ret; |
1483 | |
1484 | ret = rw_verify_area(WRITE, file_out, &pos_out, len); |
1485 | if (unlikely(ret)) |
1486 | return ret; |
1487 | |
1488 | if (len == 0) |
1489 | return 0; |
1490 | |
1491 | file_start_write(file_out); |
1492 | |
1493 | /* |
1494 | * Cloning is supported by more file systems, so we implement copy on |
1495 | * same sb using clone, but for filesystems where both clone and copy |
1496 | * are supported (e.g. nfs,cifs), we only call the copy method. |
1497 | */ |
1498 | if (file_out->f_op->copy_file_range) { |
1499 | ret = file_out->f_op->copy_file_range(file_in, pos_in, |
1500 | file_out, pos_out, |
1501 | len, flags); |
1502 | goto done; |
1503 | } |
1504 | |
1505 | if (file_in->f_op->remap_file_range && |
1506 | file_inode(file_in)->i_sb == file_inode(file_out)->i_sb) { |
1507 | ret = file_in->f_op->remap_file_range(file_in, pos_in, |
1508 | file_out, pos_out, |
1509 | min_t(loff_t, MAX_RW_COUNT, len), |
1510 | REMAP_FILE_CAN_SHORTEN); |
1511 | if (ret > 0) |
1512 | goto done; |
1513 | } |
1514 | |
1515 | /* |
1516 | * We can get here for same sb copy of filesystems that do not implement |
1517 | * ->copy_file_range() in case filesystem does not support clone or in |
1518 | * case filesystem supports clone but rejected the clone request (e.g. |
1519 | * because it was not block aligned). |
1520 | * |
1521 | * In both cases, fall back to kernel copy so we are able to maintain a |
1522 | * consistent story about which filesystems support copy_file_range() |
1523 | * and which filesystems do not, that will allow userspace tools to |
1524 | * make consistent desicions w.r.t using copy_file_range(). |
1525 | */ |
1526 | ret = generic_copy_file_range(file_in, pos_in, file_out, pos_out, len, |
1527 | flags); |
1528 | |
1529 | done: |
1530 | if (ret > 0) { |
1531 | fsnotify_access(file_in); |
1532 | add_rchar(current, ret); |
1533 | fsnotify_modify(file_out); |
1534 | add_wchar(current, ret); |
1535 | } |
1536 | |
1537 | inc_syscr(current); |
1538 | inc_syscw(current); |
1539 | |
1540 | file_end_write(file_out); |
1541 | |
1542 | return ret; |
1543 | } |
1544 | EXPORT_SYMBOL(vfs_copy_file_range); |
1545 | |
1546 | SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in, |
1547 | int, fd_out, loff_t __user *, off_out, |
1548 | size_t, len, unsigned int, flags) |
1549 | { |
1550 | loff_t pos_in; |
1551 | loff_t pos_out; |
1552 | struct fd f_in; |
1553 | struct fd f_out; |
1554 | ssize_t ret = -EBADF; |
1555 | |
1556 | f_in = fdget(fd_in); |
1557 | if (!f_in.file) |
1558 | goto out2; |
1559 | |
1560 | f_out = fdget(fd_out); |
1561 | if (!f_out.file) |
1562 | goto out1; |
1563 | |
1564 | ret = -EFAULT; |
1565 | if (off_in) { |
1566 | if (copy_from_user(&pos_in, off_in, sizeof(loff_t))) |
1567 | goto out; |
1568 | } else { |
1569 | pos_in = f_in.file->f_pos; |
1570 | } |
1571 | |
1572 | if (off_out) { |
1573 | if (copy_from_user(&pos_out, off_out, sizeof(loff_t))) |
1574 | goto out; |
1575 | } else { |
1576 | pos_out = f_out.file->f_pos; |
1577 | } |
1578 | |
1579 | ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len, |
1580 | flags); |
1581 | if (ret > 0) { |
1582 | pos_in += ret; |
1583 | pos_out += ret; |
1584 | |
1585 | if (off_in) { |
1586 | if (copy_to_user(off_in, &pos_in, sizeof(loff_t))) |
1587 | ret = -EFAULT; |
1588 | } else { |
1589 | f_in.file->f_pos = pos_in; |
1590 | } |
1591 | |
1592 | if (off_out) { |
1593 | if (copy_to_user(off_out, &pos_out, sizeof(loff_t))) |
1594 | ret = -EFAULT; |
1595 | } else { |
1596 | f_out.file->f_pos = pos_out; |
1597 | } |
1598 | } |
1599 | |
1600 | out: |
1601 | fdput(f_out); |
1602 | out1: |
1603 | fdput(f_in); |
1604 | out2: |
1605 | return ret; |
1606 | } |
1607 | |
1608 | /* |
1609 | * Don't operate on ranges the page cache doesn't support, and don't exceed the |
1610 | * LFS limits. If pos is under the limit it becomes a short access. If it |
1611 | * exceeds the limit we return -EFBIG. |
1612 | */ |
1613 | int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count) |
1614 | { |
1615 | struct inode *inode = file->f_mapping->host; |
1616 | loff_t max_size = inode->i_sb->s_maxbytes; |
1617 | loff_t limit = rlimit(RLIMIT_FSIZE); |
1618 | |
1619 | if (limit != RLIM_INFINITY) { |
1620 | if (pos >= limit) { |
1621 | send_sig(SIGXFSZ, current, 0); |
1622 | return -EFBIG; |
1623 | } |
1624 | *count = min(*count, limit - pos); |
1625 | } |
1626 | |
1627 | if (!(file->f_flags & O_LARGEFILE)) |
1628 | max_size = MAX_NON_LFS; |
1629 | |
1630 | if (unlikely(pos >= max_size)) |
1631 | return -EFBIG; |
1632 | |
1633 | *count = min(*count, max_size - pos); |
1634 | |
1635 | return 0; |
1636 | } |
1637 | |
1638 | /* Like generic_write_checks(), but takes size of write instead of iter. */ |
1639 | int generic_write_checks_count(struct kiocb *iocb, loff_t *count) |
1640 | { |
1641 | struct file *file = iocb->ki_filp; |
1642 | struct inode *inode = file->f_mapping->host; |
1643 | |
1644 | if (IS_SWAPFILE(inode)) |
1645 | return -ETXTBSY; |
1646 | |
1647 | if (!*count) |
1648 | return 0; |
1649 | |
1650 | if (iocb->ki_flags & IOCB_APPEND) |
1651 | iocb->ki_pos = i_size_read(inode); |
1652 | |
1653 | if ((iocb->ki_flags & IOCB_NOWAIT) && |
1654 | !((iocb->ki_flags & IOCB_DIRECT) || |
1655 | (file->f_mode & FMODE_BUF_WASYNC))) |
1656 | return -EINVAL; |
1657 | |
1658 | return generic_write_check_limits(iocb->ki_filp, iocb->ki_pos, count); |
1659 | } |
1660 | EXPORT_SYMBOL(generic_write_checks_count); |
1661 | |
1662 | /* |
1663 | * Performs necessary checks before doing a write |
1664 | * |
1665 | * Can adjust writing position or amount of bytes to write. |
1666 | * Returns appropriate error code that caller should return or |
1667 | * zero in case that write should be allowed. |
1668 | */ |
1669 | ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) |
1670 | { |
1671 | loff_t count = iov_iter_count(from); |
1672 | int ret; |
1673 | |
1674 | ret = generic_write_checks_count(iocb, &count); |
1675 | if (ret) |
1676 | return ret; |
1677 | |
1678 | iov_iter_truncate(from, count); |
1679 | return iov_iter_count(from); |
1680 | } |
1681 | EXPORT_SYMBOL(generic_write_checks); |
1682 | |
1683 | /* |
1684 | * Performs common checks before doing a file copy/clone |
1685 | * from @file_in to @file_out. |
1686 | */ |
1687 | int generic_file_rw_checks(struct file *file_in, struct file *file_out) |
1688 | { |
1689 | struct inode *inode_in = file_inode(file_in); |
1690 | struct inode *inode_out = file_inode(file_out); |
1691 | |
1692 | /* Don't copy dirs, pipes, sockets... */ |
1693 | if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode)) |
1694 | return -EISDIR; |
1695 | if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) |
1696 | return -EINVAL; |
1697 | |
1698 | if (!(file_in->f_mode & FMODE_READ) || |
1699 | !(file_out->f_mode & FMODE_WRITE) || |
1700 | (file_out->f_flags & O_APPEND)) |
1701 | return -EBADF; |
1702 | |
1703 | return 0; |
1704 | } |
1705 | |