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1 | /* |
2 | * linux/fs/read_write.c |
3 | * |
4 | * Copyright (C) 1991, 1992 Linus Torvalds |
5 | */ |
6 | |
7 | #include <linux/slab.h> |
8 | #include <linux/stat.h> |
9 | #include <linux/fcntl.h> |
10 | #include <linux/file.h> |
11 | #include <linux/uio.h> |
12 | #include <linux/smp_lock.h> |
13 | #include <linux/fsnotify.h> |
14 | #include <linux/security.h> |
15 | #include <linux/module.h> |
16 | #include <linux/syscalls.h> |
17 | #include <linux/pagemap.h> |
18 | #include <linux/splice.h> |
19 | #include "read_write.h" |
20 | |
21 | #include <asm/uaccess.h> |
22 | #include <asm/unistd.h> |
23 | |
24 | const struct file_operations generic_ro_fops = { |
25 | .llseek = generic_file_llseek, |
26 | .read = do_sync_read, |
27 | .aio_read = generic_file_aio_read, |
28 | .mmap = generic_file_readonly_mmap, |
29 | .splice_read = generic_file_splice_read, |
30 | }; |
31 | |
32 | EXPORT_SYMBOL(generic_ro_fops); |
33 | |
34 | /** |
35 | * generic_file_llseek_unlocked - lockless generic llseek implementation |
36 | * @file: file structure to seek on |
37 | * @offset: file offset to seek to |
38 | * @origin: type of seek |
39 | * |
40 | * Updates the file offset to the value specified by @offset and @origin. |
41 | * Locking must be provided by the caller. |
42 | */ |
43 | loff_t |
44 | generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin) |
45 | { |
46 | struct inode *inode = file->f_mapping->host; |
47 | |
48 | switch (origin) { |
49 | case SEEK_END: |
50 | offset += inode->i_size; |
51 | break; |
52 | case SEEK_CUR: |
53 | /* |
54 | * Here we special-case the lseek(fd, 0, SEEK_CUR) |
55 | * position-querying operation. Avoid rewriting the "same" |
56 | * f_pos value back to the file because a concurrent read(), |
57 | * write() or lseek() might have altered it |
58 | */ |
59 | if (offset == 0) |
60 | return file->f_pos; |
61 | offset += file->f_pos; |
62 | break; |
63 | } |
64 | |
65 | if (offset < 0 || offset > inode->i_sb->s_maxbytes) |
66 | return -EINVAL; |
67 | |
68 | /* Special lock needed here? */ |
69 | if (offset != file->f_pos) { |
70 | file->f_pos = offset; |
71 | file->f_version = 0; |
72 | } |
73 | |
74 | return offset; |
75 | } |
76 | EXPORT_SYMBOL(generic_file_llseek_unlocked); |
77 | |
78 | /** |
79 | * generic_file_llseek - generic llseek implementation for regular files |
80 | * @file: file structure to seek on |
81 | * @offset: file offset to seek to |
82 | * @origin: type of seek |
83 | * |
84 | * This is a generic implemenation of ->llseek useable for all normal local |
85 | * filesystems. It just updates the file offset to the value specified by |
86 | * @offset and @origin under i_mutex. |
87 | */ |
88 | loff_t generic_file_llseek(struct file *file, loff_t offset, int origin) |
89 | { |
90 | loff_t rval; |
91 | |
92 | mutex_lock(&file->f_dentry->d_inode->i_mutex); |
93 | rval = generic_file_llseek_unlocked(file, offset, origin); |
94 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); |
95 | |
96 | return rval; |
97 | } |
98 | EXPORT_SYMBOL(generic_file_llseek); |
99 | |
100 | loff_t no_llseek(struct file *file, loff_t offset, int origin) |
101 | { |
102 | return -ESPIPE; |
103 | } |
104 | EXPORT_SYMBOL(no_llseek); |
105 | |
106 | loff_t default_llseek(struct file *file, loff_t offset, int origin) |
107 | { |
108 | loff_t retval; |
109 | |
110 | lock_kernel(); |
111 | switch (origin) { |
112 | case SEEK_END: |
113 | offset += i_size_read(file->f_path.dentry->d_inode); |
114 | break; |
115 | case SEEK_CUR: |
116 | if (offset == 0) { |
117 | retval = file->f_pos; |
118 | goto out; |
119 | } |
120 | offset += file->f_pos; |
121 | } |
122 | retval = -EINVAL; |
123 | if (offset >= 0) { |
124 | if (offset != file->f_pos) { |
125 | file->f_pos = offset; |
126 | file->f_version = 0; |
127 | } |
128 | retval = offset; |
129 | } |
130 | out: |
131 | unlock_kernel(); |
132 | return retval; |
133 | } |
134 | EXPORT_SYMBOL(default_llseek); |
135 | |
136 | loff_t vfs_llseek(struct file *file, loff_t offset, int origin) |
137 | { |
138 | loff_t (*fn)(struct file *, loff_t, int); |
139 | |
140 | fn = no_llseek; |
141 | if (file->f_mode & FMODE_LSEEK) { |
142 | fn = default_llseek; |
143 | if (file->f_op && file->f_op->llseek) |
144 | fn = file->f_op->llseek; |
145 | } |
146 | return fn(file, offset, origin); |
147 | } |
148 | EXPORT_SYMBOL(vfs_llseek); |
149 | |
150 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, origin) |
151 | { |
152 | off_t retval; |
153 | struct file * file; |
154 | int fput_needed; |
155 | |
156 | retval = -EBADF; |
157 | file = fget_light(fd, &fput_needed); |
158 | if (!file) |
159 | goto bad; |
160 | |
161 | retval = -EINVAL; |
162 | if (origin <= SEEK_MAX) { |
163 | loff_t res = vfs_llseek(file, offset, origin); |
164 | retval = res; |
165 | if (res != (loff_t)retval) |
166 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ |
167 | } |
168 | fput_light(file, fput_needed); |
169 | bad: |
170 | return retval; |
171 | } |
172 | |
173 | #ifdef __ARCH_WANT_SYS_LLSEEK |
174 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, |
175 | unsigned long, offset_low, loff_t __user *, result, |
176 | unsigned int, origin) |
177 | { |
178 | int retval; |
179 | struct file * file; |
180 | loff_t offset; |
181 | int fput_needed; |
182 | |
183 | retval = -EBADF; |
184 | file = fget_light(fd, &fput_needed); |
185 | if (!file) |
186 | goto bad; |
187 | |
188 | retval = -EINVAL; |
189 | if (origin > SEEK_MAX) |
190 | goto out_putf; |
191 | |
192 | offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low, |
193 | origin); |
194 | |
195 | retval = (int)offset; |
196 | if (offset >= 0) { |
197 | retval = -EFAULT; |
198 | if (!copy_to_user(result, &offset, sizeof(offset))) |
199 | retval = 0; |
200 | } |
201 | out_putf: |
202 | fput_light(file, fput_needed); |
203 | bad: |
204 | return retval; |
205 | } |
206 | #endif |
207 | |
208 | /* |
209 | * rw_verify_area doesn't like huge counts. We limit |
210 | * them to something that fits in "int" so that others |
211 | * won't have to do range checks all the time. |
212 | */ |
213 | #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK) |
214 | |
215 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) |
216 | { |
217 | struct inode *inode; |
218 | loff_t pos; |
219 | int retval = -EINVAL; |
220 | |
221 | inode = file->f_path.dentry->d_inode; |
222 | if (unlikely((ssize_t) count < 0)) |
223 | return retval; |
224 | pos = *ppos; |
225 | if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) |
226 | return retval; |
227 | |
228 | if (unlikely(inode->i_flock && mandatory_lock(inode))) { |
229 | retval = locks_mandatory_area( |
230 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, |
231 | inode, file, pos, count); |
232 | if (retval < 0) |
233 | return retval; |
234 | } |
235 | retval = security_file_permission(file, |
236 | read_write == READ ? MAY_READ : MAY_WRITE); |
237 | if (retval) |
238 | return retval; |
239 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; |
240 | } |
241 | |
242 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) |
243 | { |
244 | set_current_state(TASK_UNINTERRUPTIBLE); |
245 | if (!kiocbIsKicked(iocb)) |
246 | schedule(); |
247 | else |
248 | kiocbClearKicked(iocb); |
249 | __set_current_state(TASK_RUNNING); |
250 | } |
251 | |
252 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) |
253 | { |
254 | struct iovec iov = { .iov_base = buf, .iov_len = len }; |
255 | struct kiocb kiocb; |
256 | ssize_t ret; |
257 | |
258 | init_sync_kiocb(&kiocb, filp); |
259 | kiocb.ki_pos = *ppos; |
260 | kiocb.ki_left = len; |
261 | kiocb.ki_nbytes = len; |
262 | |
263 | for (;;) { |
264 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); |
265 | if (ret != -EIOCBRETRY) |
266 | break; |
267 | wait_on_retry_sync_kiocb(&kiocb); |
268 | } |
269 | |
270 | if (-EIOCBQUEUED == ret) |
271 | ret = wait_on_sync_kiocb(&kiocb); |
272 | *ppos = kiocb.ki_pos; |
273 | return ret; |
274 | } |
275 | |
276 | EXPORT_SYMBOL(do_sync_read); |
277 | |
278 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) |
279 | { |
280 | ssize_t ret; |
281 | |
282 | if (!(file->f_mode & FMODE_READ)) |
283 | return -EBADF; |
284 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) |
285 | return -EINVAL; |
286 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) |
287 | return -EFAULT; |
288 | |
289 | ret = rw_verify_area(READ, file, pos, count); |
290 | if (ret >= 0) { |
291 | count = ret; |
292 | if (file->f_op->read) |
293 | ret = file->f_op->read(file, buf, count, pos); |
294 | else |
295 | ret = do_sync_read(file, buf, count, pos); |
296 | if (ret > 0) { |
297 | fsnotify_access(file->f_path.dentry); |
298 | add_rchar(current, ret); |
299 | } |
300 | inc_syscr(current); |
301 | } |
302 | |
303 | return ret; |
304 | } |
305 | |
306 | EXPORT_SYMBOL(vfs_read); |
307 | |
308 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) |
309 | { |
310 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; |
311 | struct kiocb kiocb; |
312 | ssize_t ret; |
313 | |
314 | init_sync_kiocb(&kiocb, filp); |
315 | kiocb.ki_pos = *ppos; |
316 | kiocb.ki_left = len; |
317 | kiocb.ki_nbytes = len; |
318 | |
319 | for (;;) { |
320 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); |
321 | if (ret != -EIOCBRETRY) |
322 | break; |
323 | wait_on_retry_sync_kiocb(&kiocb); |
324 | } |
325 | |
326 | if (-EIOCBQUEUED == ret) |
327 | ret = wait_on_sync_kiocb(&kiocb); |
328 | *ppos = kiocb.ki_pos; |
329 | return ret; |
330 | } |
331 | |
332 | EXPORT_SYMBOL(do_sync_write); |
333 | |
334 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
335 | { |
336 | ssize_t ret; |
337 | |
338 | if (!(file->f_mode & FMODE_WRITE)) |
339 | return -EBADF; |
340 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) |
341 | return -EINVAL; |
342 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) |
343 | return -EFAULT; |
344 | |
345 | ret = rw_verify_area(WRITE, file, pos, count); |
346 | if (ret >= 0) { |
347 | count = ret; |
348 | if (file->f_op->write) |
349 | ret = file->f_op->write(file, buf, count, pos); |
350 | else |
351 | ret = do_sync_write(file, buf, count, pos); |
352 | if (ret > 0) { |
353 | fsnotify_modify(file->f_path.dentry); |
354 | add_wchar(current, ret); |
355 | } |
356 | inc_syscw(current); |
357 | } |
358 | |
359 | return ret; |
360 | } |
361 | |
362 | EXPORT_SYMBOL(vfs_write); |
363 | |
364 | static inline loff_t file_pos_read(struct file *file) |
365 | { |
366 | return file->f_pos; |
367 | } |
368 | |
369 | static inline void file_pos_write(struct file *file, loff_t pos) |
370 | { |
371 | file->f_pos = pos; |
372 | } |
373 | |
374 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) |
375 | { |
376 | struct file *file; |
377 | ssize_t ret = -EBADF; |
378 | int fput_needed; |
379 | |
380 | file = fget_light(fd, &fput_needed); |
381 | if (file) { |
382 | loff_t pos = file_pos_read(file); |
383 | ret = vfs_read(file, buf, count, &pos); |
384 | file_pos_write(file, pos); |
385 | fput_light(file, fput_needed); |
386 | } |
387 | |
388 | return ret; |
389 | } |
390 | |
391 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, |
392 | size_t, count) |
393 | { |
394 | struct file *file; |
395 | ssize_t ret = -EBADF; |
396 | int fput_needed; |
397 | |
398 | file = fget_light(fd, &fput_needed); |
399 | if (file) { |
400 | loff_t pos = file_pos_read(file); |
401 | ret = vfs_write(file, buf, count, &pos); |
402 | file_pos_write(file, pos); |
403 | fput_light(file, fput_needed); |
404 | } |
405 | |
406 | return ret; |
407 | } |
408 | |
409 | SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf, |
410 | size_t count, loff_t pos) |
411 | { |
412 | struct file *file; |
413 | ssize_t ret = -EBADF; |
414 | int fput_needed; |
415 | |
416 | if (pos < 0) |
417 | return -EINVAL; |
418 | |
419 | file = fget_light(fd, &fput_needed); |
420 | if (file) { |
421 | ret = -ESPIPE; |
422 | if (file->f_mode & FMODE_PREAD) |
423 | ret = vfs_read(file, buf, count, &pos); |
424 | fput_light(file, fput_needed); |
425 | } |
426 | |
427 | return ret; |
428 | } |
429 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
430 | asmlinkage long SyS_pread64(long fd, long buf, long count, loff_t pos) |
431 | { |
432 | return SYSC_pread64((unsigned int) fd, (char __user *) buf, |
433 | (size_t) count, pos); |
434 | } |
435 | SYSCALL_ALIAS(sys_pread64, SyS_pread64); |
436 | #endif |
437 | |
438 | SYSCALL_DEFINE(pwrite64)(unsigned int fd, const char __user *buf, |
439 | size_t count, loff_t pos) |
440 | { |
441 | struct file *file; |
442 | ssize_t ret = -EBADF; |
443 | int fput_needed; |
444 | |
445 | if (pos < 0) |
446 | return -EINVAL; |
447 | |
448 | file = fget_light(fd, &fput_needed); |
449 | if (file) { |
450 | ret = -ESPIPE; |
451 | if (file->f_mode & FMODE_PWRITE) |
452 | ret = vfs_write(file, buf, count, &pos); |
453 | fput_light(file, fput_needed); |
454 | } |
455 | |
456 | return ret; |
457 | } |
458 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
459 | asmlinkage long SyS_pwrite64(long fd, long buf, long count, loff_t pos) |
460 | { |
461 | return SYSC_pwrite64((unsigned int) fd, (const char __user *) buf, |
462 | (size_t) count, pos); |
463 | } |
464 | SYSCALL_ALIAS(sys_pwrite64, SyS_pwrite64); |
465 | #endif |
466 | |
467 | /* |
468 | * Reduce an iovec's length in-place. Return the resulting number of segments |
469 | */ |
470 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) |
471 | { |
472 | unsigned long seg = 0; |
473 | size_t len = 0; |
474 | |
475 | while (seg < nr_segs) { |
476 | seg++; |
477 | if (len + iov->iov_len >= to) { |
478 | iov->iov_len = to - len; |
479 | break; |
480 | } |
481 | len += iov->iov_len; |
482 | iov++; |
483 | } |
484 | return seg; |
485 | } |
486 | EXPORT_SYMBOL(iov_shorten); |
487 | |
488 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, |
489 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) |
490 | { |
491 | struct kiocb kiocb; |
492 | ssize_t ret; |
493 | |
494 | init_sync_kiocb(&kiocb, filp); |
495 | kiocb.ki_pos = *ppos; |
496 | kiocb.ki_left = len; |
497 | kiocb.ki_nbytes = len; |
498 | |
499 | for (;;) { |
500 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); |
501 | if (ret != -EIOCBRETRY) |
502 | break; |
503 | wait_on_retry_sync_kiocb(&kiocb); |
504 | } |
505 | |
506 | if (ret == -EIOCBQUEUED) |
507 | ret = wait_on_sync_kiocb(&kiocb); |
508 | *ppos = kiocb.ki_pos; |
509 | return ret; |
510 | } |
511 | |
512 | /* Do it by hand, with file-ops */ |
513 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, |
514 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) |
515 | { |
516 | struct iovec *vector = iov; |
517 | ssize_t ret = 0; |
518 | |
519 | while (nr_segs > 0) { |
520 | void __user *base; |
521 | size_t len; |
522 | ssize_t nr; |
523 | |
524 | base = vector->iov_base; |
525 | len = vector->iov_len; |
526 | vector++; |
527 | nr_segs--; |
528 | |
529 | nr = fn(filp, base, len, ppos); |
530 | |
531 | if (nr < 0) { |
532 | if (!ret) |
533 | ret = nr; |
534 | break; |
535 | } |
536 | ret += nr; |
537 | if (nr != len) |
538 | break; |
539 | } |
540 | |
541 | return ret; |
542 | } |
543 | |
544 | /* A write operation does a read from user space and vice versa */ |
545 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) |
546 | |
547 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, |
548 | unsigned long nr_segs, unsigned long fast_segs, |
549 | struct iovec *fast_pointer, |
550 | struct iovec **ret_pointer) |
551 | { |
552 | unsigned long seg; |
553 | ssize_t ret; |
554 | struct iovec *iov = fast_pointer; |
555 | |
556 | /* |
557 | * SuS says "The readv() function *may* fail if the iovcnt argument |
558 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has |
559 | * traditionally returned zero for zero segments, so... |
560 | */ |
561 | if (nr_segs == 0) { |
562 | ret = 0; |
563 | goto out; |
564 | } |
565 | |
566 | /* |
567 | * First get the "struct iovec" from user memory and |
568 | * verify all the pointers |
569 | */ |
570 | if (nr_segs > UIO_MAXIOV) { |
571 | ret = -EINVAL; |
572 | goto out; |
573 | } |
574 | if (nr_segs > fast_segs) { |
575 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); |
576 | if (iov == NULL) { |
577 | ret = -ENOMEM; |
578 | goto out; |
579 | } |
580 | } |
581 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { |
582 | ret = -EFAULT; |
583 | goto out; |
584 | } |
585 | |
586 | /* |
587 | * According to the Single Unix Specification we should return EINVAL |
588 | * if an element length is < 0 when cast to ssize_t or if the |
589 | * total length would overflow the ssize_t return value of the |
590 | * system call. |
591 | */ |
592 | ret = 0; |
593 | for (seg = 0; seg < nr_segs; seg++) { |
594 | void __user *buf = iov[seg].iov_base; |
595 | ssize_t len = (ssize_t)iov[seg].iov_len; |
596 | |
597 | /* see if we we're about to use an invalid len or if |
598 | * it's about to overflow ssize_t */ |
599 | if (len < 0 || (ret + len < ret)) { |
600 | ret = -EINVAL; |
601 | goto out; |
602 | } |
603 | if (unlikely(!access_ok(vrfy_dir(type), buf, len))) { |
604 | ret = -EFAULT; |
605 | goto out; |
606 | } |
607 | |
608 | ret += len; |
609 | } |
610 | out: |
611 | *ret_pointer = iov; |
612 | return ret; |
613 | } |
614 | |
615 | static ssize_t do_readv_writev(int type, struct file *file, |
616 | const struct iovec __user * uvector, |
617 | unsigned long nr_segs, loff_t *pos) |
618 | { |
619 | size_t tot_len; |
620 | struct iovec iovstack[UIO_FASTIOV]; |
621 | struct iovec *iov = iovstack; |
622 | ssize_t ret; |
623 | io_fn_t fn; |
624 | iov_fn_t fnv; |
625 | |
626 | if (!file->f_op) { |
627 | ret = -EINVAL; |
628 | goto out; |
629 | } |
630 | |
631 | ret = rw_copy_check_uvector(type, uvector, nr_segs, |
632 | ARRAY_SIZE(iovstack), iovstack, &iov); |
633 | if (ret <= 0) |
634 | goto out; |
635 | |
636 | tot_len = ret; |
637 | ret = rw_verify_area(type, file, pos, tot_len); |
638 | if (ret < 0) |
639 | goto out; |
640 | |
641 | fnv = NULL; |
642 | if (type == READ) { |
643 | fn = file->f_op->read; |
644 | fnv = file->f_op->aio_read; |
645 | } else { |
646 | fn = (io_fn_t)file->f_op->write; |
647 | fnv = file->f_op->aio_write; |
648 | } |
649 | |
650 | if (fnv) |
651 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, |
652 | pos, fnv); |
653 | else |
654 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); |
655 | |
656 | out: |
657 | if (iov != iovstack) |
658 | kfree(iov); |
659 | if ((ret + (type == READ)) > 0) { |
660 | if (type == READ) |
661 | fsnotify_access(file->f_path.dentry); |
662 | else |
663 | fsnotify_modify(file->f_path.dentry); |
664 | } |
665 | return ret; |
666 | } |
667 | |
668 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, |
669 | unsigned long vlen, loff_t *pos) |
670 | { |
671 | if (!(file->f_mode & FMODE_READ)) |
672 | return -EBADF; |
673 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) |
674 | return -EINVAL; |
675 | |
676 | return do_readv_writev(READ, file, vec, vlen, pos); |
677 | } |
678 | |
679 | EXPORT_SYMBOL(vfs_readv); |
680 | |
681 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, |
682 | unsigned long vlen, loff_t *pos) |
683 | { |
684 | if (!(file->f_mode & FMODE_WRITE)) |
685 | return -EBADF; |
686 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) |
687 | return -EINVAL; |
688 | |
689 | return do_readv_writev(WRITE, file, vec, vlen, pos); |
690 | } |
691 | |
692 | EXPORT_SYMBOL(vfs_writev); |
693 | |
694 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, |
695 | unsigned long, vlen) |
696 | { |
697 | struct file *file; |
698 | ssize_t ret = -EBADF; |
699 | int fput_needed; |
700 | |
701 | file = fget_light(fd, &fput_needed); |
702 | if (file) { |
703 | loff_t pos = file_pos_read(file); |
704 | ret = vfs_readv(file, vec, vlen, &pos); |
705 | file_pos_write(file, pos); |
706 | fput_light(file, fput_needed); |
707 | } |
708 | |
709 | if (ret > 0) |
710 | add_rchar(current, ret); |
711 | inc_syscr(current); |
712 | return ret; |
713 | } |
714 | |
715 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, |
716 | unsigned long, vlen) |
717 | { |
718 | struct file *file; |
719 | ssize_t ret = -EBADF; |
720 | int fput_needed; |
721 | |
722 | file = fget_light(fd, &fput_needed); |
723 | if (file) { |
724 | loff_t pos = file_pos_read(file); |
725 | ret = vfs_writev(file, vec, vlen, &pos); |
726 | file_pos_write(file, pos); |
727 | fput_light(file, fput_needed); |
728 | } |
729 | |
730 | if (ret > 0) |
731 | add_wchar(current, ret); |
732 | inc_syscw(current); |
733 | return ret; |
734 | } |
735 | |
736 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) |
737 | { |
738 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) |
739 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; |
740 | } |
741 | |
742 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, |
743 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
744 | { |
745 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
746 | struct file *file; |
747 | ssize_t ret = -EBADF; |
748 | int fput_needed; |
749 | |
750 | if (pos < 0) |
751 | return -EINVAL; |
752 | |
753 | file = fget_light(fd, &fput_needed); |
754 | if (file) { |
755 | ret = -ESPIPE; |
756 | if (file->f_mode & FMODE_PREAD) |
757 | ret = vfs_readv(file, vec, vlen, &pos); |
758 | fput_light(file, fput_needed); |
759 | } |
760 | |
761 | if (ret > 0) |
762 | add_rchar(current, ret); |
763 | inc_syscr(current); |
764 | return ret; |
765 | } |
766 | |
767 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, |
768 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
769 | { |
770 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
771 | struct file *file; |
772 | ssize_t ret = -EBADF; |
773 | int fput_needed; |
774 | |
775 | if (pos < 0) |
776 | return -EINVAL; |
777 | |
778 | file = fget_light(fd, &fput_needed); |
779 | if (file) { |
780 | ret = -ESPIPE; |
781 | if (file->f_mode & FMODE_PWRITE) |
782 | ret = vfs_writev(file, vec, vlen, &pos); |
783 | fput_light(file, fput_needed); |
784 | } |
785 | |
786 | if (ret > 0) |
787 | add_wchar(current, ret); |
788 | inc_syscw(current); |
789 | return ret; |
790 | } |
791 | |
792 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, |
793 | size_t count, loff_t max) |
794 | { |
795 | struct file * in_file, * out_file; |
796 | struct inode * in_inode, * out_inode; |
797 | loff_t pos; |
798 | ssize_t retval; |
799 | int fput_needed_in, fput_needed_out, fl; |
800 | |
801 | /* |
802 | * Get input file, and verify that it is ok.. |
803 | */ |
804 | retval = -EBADF; |
805 | in_file = fget_light(in_fd, &fput_needed_in); |
806 | if (!in_file) |
807 | goto out; |
808 | if (!(in_file->f_mode & FMODE_READ)) |
809 | goto fput_in; |
810 | retval = -ESPIPE; |
811 | if (!ppos) |
812 | ppos = &in_file->f_pos; |
813 | else |
814 | if (!(in_file->f_mode & FMODE_PREAD)) |
815 | goto fput_in; |
816 | retval = rw_verify_area(READ, in_file, ppos, count); |
817 | if (retval < 0) |
818 | goto fput_in; |
819 | count = retval; |
820 | |
821 | /* |
822 | * Get output file, and verify that it is ok.. |
823 | */ |
824 | retval = -EBADF; |
825 | out_file = fget_light(out_fd, &fput_needed_out); |
826 | if (!out_file) |
827 | goto fput_in; |
828 | if (!(out_file->f_mode & FMODE_WRITE)) |
829 | goto fput_out; |
830 | retval = -EINVAL; |
831 | in_inode = in_file->f_path.dentry->d_inode; |
832 | out_inode = out_file->f_path.dentry->d_inode; |
833 | retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count); |
834 | if (retval < 0) |
835 | goto fput_out; |
836 | count = retval; |
837 | |
838 | if (!max) |
839 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); |
840 | |
841 | pos = *ppos; |
842 | if (unlikely(pos + count > max)) { |
843 | retval = -EOVERFLOW; |
844 | if (pos >= max) |
845 | goto fput_out; |
846 | count = max - pos; |
847 | } |
848 | |
849 | fl = 0; |
850 | #if 0 |
851 | /* |
852 | * We need to debate whether we can enable this or not. The |
853 | * man page documents EAGAIN return for the output at least, |
854 | * and the application is arguably buggy if it doesn't expect |
855 | * EAGAIN on a non-blocking file descriptor. |
856 | */ |
857 | if (in_file->f_flags & O_NONBLOCK) |
858 | fl = SPLICE_F_NONBLOCK; |
859 | #endif |
860 | retval = do_splice_direct(in_file, ppos, out_file, count, fl); |
861 | |
862 | if (retval > 0) { |
863 | add_rchar(current, retval); |
864 | add_wchar(current, retval); |
865 | } |
866 | |
867 | inc_syscr(current); |
868 | inc_syscw(current); |
869 | if (*ppos > max) |
870 | retval = -EOVERFLOW; |
871 | |
872 | fput_out: |
873 | fput_light(out_file, fput_needed_out); |
874 | fput_in: |
875 | fput_light(in_file, fput_needed_in); |
876 | out: |
877 | return retval; |
878 | } |
879 | |
880 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) |
881 | { |
882 | loff_t pos; |
883 | off_t off; |
884 | ssize_t ret; |
885 | |
886 | if (offset) { |
887 | if (unlikely(get_user(off, offset))) |
888 | return -EFAULT; |
889 | pos = off; |
890 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); |
891 | if (unlikely(put_user(pos, offset))) |
892 | return -EFAULT; |
893 | return ret; |
894 | } |
895 | |
896 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
897 | } |
898 | |
899 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) |
900 | { |
901 | loff_t pos; |
902 | ssize_t ret; |
903 | |
904 | if (offset) { |
905 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) |
906 | return -EFAULT; |
907 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); |
908 | if (unlikely(put_user(pos, offset))) |
909 | return -EFAULT; |
910 | return ret; |
911 | } |
912 | |
913 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
914 | } |
915 |
Branches:
ben-wpan
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javiroman/ks7010
jz-2.6.34
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9