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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 | loff_t generic_file_llseek(struct file *file, loff_t offset, int origin) | |
35 | { | |
36 | long long retval; | |
37 | struct inode *inode = file->f_mapping->host; | |
38 | ||
39 | mutex_lock(&inode->i_mutex); | |
40 | switch (origin) { | |
41 | case SEEK_END: | |
42 | offset += inode->i_size; | |
43 | break; | |
44 | case SEEK_CUR: | |
45 | offset += file->f_pos; | |
46 | } | |
47 | retval = -EINVAL; | |
48 | if (offset>=0 && offset<=inode->i_sb->s_maxbytes) { | |
49 | if (offset != file->f_pos) { | |
50 | file->f_pos = offset; | |
51 | file->f_version = 0; | |
52 | } | |
53 | retval = offset; | |
54 | } | |
55 | mutex_unlock(&inode->i_mutex); | |
56 | return retval; | |
57 | } | |
58 | ||
59 | EXPORT_SYMBOL(generic_file_llseek); | |
60 | ||
61 | loff_t remote_llseek(struct file *file, loff_t offset, int origin) | |
62 | { | |
63 | long long retval; | |
64 | ||
65 | lock_kernel(); | |
66 | switch (origin) { | |
67 | case SEEK_END: | |
68 | offset += i_size_read(file->f_path.dentry->d_inode); | |
69 | break; | |
70 | case SEEK_CUR: | |
71 | offset += file->f_pos; | |
72 | } | |
73 | retval = -EINVAL; | |
74 | if (offset>=0 && offset<=file->f_path.dentry->d_inode->i_sb->s_maxbytes) { | |
75 | if (offset != file->f_pos) { | |
76 | file->f_pos = offset; | |
77 | file->f_version = 0; | |
78 | } | |
79 | retval = offset; | |
80 | } | |
81 | unlock_kernel(); | |
82 | return retval; | |
83 | } | |
84 | EXPORT_SYMBOL(remote_llseek); | |
85 | ||
86 | loff_t no_llseek(struct file *file, loff_t offset, int origin) | |
87 | { | |
88 | return -ESPIPE; | |
89 | } | |
90 | EXPORT_SYMBOL(no_llseek); | |
91 | ||
92 | loff_t default_llseek(struct file *file, loff_t offset, int origin) | |
93 | { | |
94 | long long retval; | |
95 | ||
96 | lock_kernel(); | |
97 | switch (origin) { | |
98 | case SEEK_END: | |
99 | offset += i_size_read(file->f_path.dentry->d_inode); | |
100 | break; | |
101 | case SEEK_CUR: | |
102 | offset += file->f_pos; | |
103 | } | |
104 | retval = -EINVAL; | |
105 | if (offset >= 0) { | |
106 | if (offset != file->f_pos) { | |
107 | file->f_pos = offset; | |
108 | file->f_version = 0; | |
109 | } | |
110 | retval = offset; | |
111 | } | |
112 | unlock_kernel(); | |
113 | return retval; | |
114 | } | |
115 | EXPORT_SYMBOL(default_llseek); | |
116 | ||
117 | loff_t vfs_llseek(struct file *file, loff_t offset, int origin) | |
118 | { | |
119 | loff_t (*fn)(struct file *, loff_t, int); | |
120 | ||
121 | fn = no_llseek; | |
122 | if (file->f_mode & FMODE_LSEEK) { | |
123 | fn = default_llseek; | |
124 | if (file->f_op && file->f_op->llseek) | |
125 | fn = file->f_op->llseek; | |
126 | } | |
127 | return fn(file, offset, origin); | |
128 | } | |
129 | EXPORT_SYMBOL(vfs_llseek); | |
130 | ||
131 | asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin) | |
132 | { | |
133 | off_t retval; | |
134 | struct file * file; | |
135 | int fput_needed; | |
136 | ||
137 | retval = -EBADF; | |
138 | file = fget_light(fd, &fput_needed); | |
139 | if (!file) | |
140 | goto bad; | |
141 | ||
142 | retval = -EINVAL; | |
143 | if (origin <= SEEK_MAX) { | |
144 | loff_t res = vfs_llseek(file, offset, origin); | |
145 | retval = res; | |
146 | if (res != (loff_t)retval) | |
147 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ | |
148 | } | |
149 | fput_light(file, fput_needed); | |
150 | bad: | |
151 | return retval; | |
152 | } | |
153 | ||
154 | #ifdef __ARCH_WANT_SYS_LLSEEK | |
155 | asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high, | |
156 | unsigned long offset_low, loff_t __user * result, | |
157 | unsigned int origin) | |
158 | { | |
159 | int retval; | |
160 | struct file * file; | |
161 | loff_t offset; | |
162 | int fput_needed; | |
163 | ||
164 | retval = -EBADF; | |
165 | file = fget_light(fd, &fput_needed); | |
166 | if (!file) | |
167 | goto bad; | |
168 | ||
169 | retval = -EINVAL; | |
170 | if (origin > SEEK_MAX) | |
171 | goto out_putf; | |
172 | ||
173 | offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low, | |
174 | origin); | |
175 | ||
176 | retval = (int)offset; | |
177 | if (offset >= 0) { | |
178 | retval = -EFAULT; | |
179 | if (!copy_to_user(result, &offset, sizeof(offset))) | |
180 | retval = 0; | |
181 | } | |
182 | out_putf: | |
183 | fput_light(file, fput_needed); | |
184 | bad: | |
185 | return retval; | |
186 | } | |
187 | #endif | |
188 | ||
189 | /* | |
190 | * rw_verify_area doesn't like huge counts. We limit | |
191 | * them to something that fits in "int" so that others | |
192 | * won't have to do range checks all the time. | |
193 | */ | |
194 | #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK) | |
195 | ||
196 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) | |
197 | { | |
198 | struct inode *inode; | |
199 | loff_t pos; | |
200 | ||
201 | inode = file->f_path.dentry->d_inode; | |
202 | if (unlikely((ssize_t) count < 0)) | |
203 | goto Einval; | |
204 | pos = *ppos; | |
205 | if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) | |
206 | goto Einval; | |
207 | ||
208 | if (unlikely(inode->i_flock && MANDATORY_LOCK(inode))) { | |
209 | int retval = locks_mandatory_area( | |
210 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, | |
211 | inode, file, pos, count); | |
212 | if (retval < 0) | |
213 | return retval; | |
214 | } | |
215 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; | |
216 | ||
217 | Einval: | |
218 | return -EINVAL; | |
219 | } | |
220 | ||
221 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) | |
222 | { | |
223 | set_current_state(TASK_UNINTERRUPTIBLE); | |
224 | if (!kiocbIsKicked(iocb)) | |
225 | schedule(); | |
226 | else | |
227 | kiocbClearKicked(iocb); | |
228 | __set_current_state(TASK_RUNNING); | |
229 | } | |
230 | ||
231 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) | |
232 | { | |
233 | struct iovec iov = { .iov_base = buf, .iov_len = len }; | |
234 | struct kiocb kiocb; | |
235 | ssize_t ret; | |
236 | ||
237 | init_sync_kiocb(&kiocb, filp); | |
238 | kiocb.ki_pos = *ppos; | |
239 | kiocb.ki_left = len; | |
240 | ||
241 | for (;;) { | |
242 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); | |
243 | if (ret != -EIOCBRETRY) | |
244 | break; | |
245 | wait_on_retry_sync_kiocb(&kiocb); | |
246 | } | |
247 | ||
248 | if (-EIOCBQUEUED == ret) | |
249 | ret = wait_on_sync_kiocb(&kiocb); | |
250 | *ppos = kiocb.ki_pos; | |
251 | return ret; | |
252 | } | |
253 | ||
254 | EXPORT_SYMBOL(do_sync_read); | |
255 | ||
256 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) | |
257 | { | |
258 | ssize_t ret; | |
259 | ||
260 | if (!(file->f_mode & FMODE_READ)) | |
261 | return -EBADF; | |
262 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) | |
263 | return -EINVAL; | |
264 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) | |
265 | return -EFAULT; | |
266 | ||
267 | ret = rw_verify_area(READ, file, pos, count); | |
268 | if (ret >= 0) { | |
269 | count = ret; | |
270 | ret = security_file_permission (file, MAY_READ); | |
271 | if (!ret) { | |
272 | if (file->f_op->read) | |
273 | ret = file->f_op->read(file, buf, count, pos); | |
274 | else | |
275 | ret = do_sync_read(file, buf, count, pos); | |
276 | if (ret > 0) { | |
277 | fsnotify_access(file->f_path.dentry); | |
278 | add_rchar(current, ret); | |
279 | } | |
280 | inc_syscr(current); | |
281 | } | |
282 | } | |
283 | ||
284 | return ret; | |
285 | } | |
286 | ||
287 | EXPORT_SYMBOL(vfs_read); | |
288 | ||
289 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) | |
290 | { | |
291 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; | |
292 | struct kiocb kiocb; | |
293 | ssize_t ret; | |
294 | ||
295 | init_sync_kiocb(&kiocb, filp); | |
296 | kiocb.ki_pos = *ppos; | |
297 | kiocb.ki_left = len; | |
298 | ||
299 | for (;;) { | |
300 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); | |
301 | if (ret != -EIOCBRETRY) | |
302 | break; | |
303 | wait_on_retry_sync_kiocb(&kiocb); | |
304 | } | |
305 | ||
306 | if (-EIOCBQUEUED == ret) | |
307 | ret = wait_on_sync_kiocb(&kiocb); | |
308 | *ppos = kiocb.ki_pos; | |
309 | return ret; | |
310 | } | |
311 | ||
312 | EXPORT_SYMBOL(do_sync_write); | |
313 | ||
314 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) | |
315 | { | |
316 | ssize_t ret; | |
317 | ||
318 | if (!(file->f_mode & FMODE_WRITE)) | |
319 | return -EBADF; | |
320 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) | |
321 | return -EINVAL; | |
322 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) | |
323 | return -EFAULT; | |
324 | ||
325 | ret = rw_verify_area(WRITE, file, pos, count); | |
326 | if (ret >= 0) { | |
327 | count = ret; | |
328 | ret = security_file_permission (file, MAY_WRITE); | |
329 | if (!ret) { | |
330 | if (file->f_op->write) | |
331 | ret = file->f_op->write(file, buf, count, pos); | |
332 | else | |
333 | ret = do_sync_write(file, buf, count, pos); | |
334 | if (ret > 0) { | |
335 | fsnotify_modify(file->f_path.dentry); | |
336 | add_wchar(current, ret); | |
337 | } | |
338 | inc_syscw(current); | |
339 | } | |
340 | } | |
341 | ||
342 | return ret; | |
343 | } | |
344 | ||
345 | EXPORT_SYMBOL(vfs_write); | |
346 | ||
347 | static inline loff_t file_pos_read(struct file *file) | |
348 | { | |
349 | return file->f_pos; | |
350 | } | |
351 | ||
352 | static inline void file_pos_write(struct file *file, loff_t pos) | |
353 | { | |
354 | file->f_pos = pos; | |
355 | } | |
356 | ||
357 | asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count) | |
358 | { | |
359 | struct file *file; | |
360 | ssize_t ret = -EBADF; | |
361 | int fput_needed; | |
362 | ||
363 | file = fget_light(fd, &fput_needed); | |
364 | if (file) { | |
365 | loff_t pos = file_pos_read(file); | |
366 | ret = vfs_read(file, buf, count, &pos); | |
367 | file_pos_write(file, pos); | |
368 | fput_light(file, fput_needed); | |
369 | } | |
370 | ||
371 | return ret; | |
372 | } | |
373 | EXPORT_SYMBOL_GPL(sys_read); | |
374 | ||
375 | asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count) | |
376 | { | |
377 | struct file *file; | |
378 | ssize_t ret = -EBADF; | |
379 | int fput_needed; | |
380 | ||
381 | file = fget_light(fd, &fput_needed); | |
382 | if (file) { | |
383 | loff_t pos = file_pos_read(file); | |
384 | ret = vfs_write(file, buf, count, &pos); | |
385 | file_pos_write(file, pos); | |
386 | fput_light(file, fput_needed); | |
387 | } | |
388 | ||
389 | return ret; | |
390 | } | |
391 | ||
392 | asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf, | |
393 | size_t count, loff_t pos) | |
394 | { | |
395 | struct file *file; | |
396 | ssize_t ret = -EBADF; | |
397 | int fput_needed; | |
398 | ||
399 | if (pos < 0) | |
400 | return -EINVAL; | |
401 | ||
402 | file = fget_light(fd, &fput_needed); | |
403 | if (file) { | |
404 | ret = -ESPIPE; | |
405 | if (file->f_mode & FMODE_PREAD) | |
406 | ret = vfs_read(file, buf, count, &pos); | |
407 | fput_light(file, fput_needed); | |
408 | } | |
409 | ||
410 | return ret; | |
411 | } | |
412 | ||
413 | asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf, | |
414 | size_t count, loff_t pos) | |
415 | { | |
416 | struct file *file; | |
417 | ssize_t ret = -EBADF; | |
418 | int fput_needed; | |
419 | ||
420 | if (pos < 0) | |
421 | return -EINVAL; | |
422 | ||
423 | file = fget_light(fd, &fput_needed); | |
424 | if (file) { | |
425 | ret = -ESPIPE; | |
426 | if (file->f_mode & FMODE_PWRITE) | |
427 | ret = vfs_write(file, buf, count, &pos); | |
428 | fput_light(file, fput_needed); | |
429 | } | |
430 | ||
431 | return ret; | |
432 | } | |
433 | ||
434 | /* | |
435 | * Reduce an iovec's length in-place. Return the resulting number of segments | |
436 | */ | |
437 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) | |
438 | { | |
439 | unsigned long seg = 0; | |
440 | size_t len = 0; | |
441 | ||
442 | while (seg < nr_segs) { | |
443 | seg++; | |
444 | if (len + iov->iov_len >= to) { | |
445 | iov->iov_len = to - len; | |
446 | break; | |
447 | } | |
448 | len += iov->iov_len; | |
449 | iov++; | |
450 | } | |
451 | return seg; | |
452 | } | |
453 | ||
454 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, | |
455 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) | |
456 | { | |
457 | struct kiocb kiocb; | |
458 | ssize_t ret; | |
459 | ||
460 | init_sync_kiocb(&kiocb, filp); | |
461 | kiocb.ki_pos = *ppos; | |
462 | kiocb.ki_left = len; | |
463 | kiocb.ki_nbytes = len; | |
464 | ||
465 | for (;;) { | |
466 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); | |
467 | if (ret != -EIOCBRETRY) | |
468 | break; | |
469 | wait_on_retry_sync_kiocb(&kiocb); | |
470 | } | |
471 | ||
472 | if (ret == -EIOCBQUEUED) | |
473 | ret = wait_on_sync_kiocb(&kiocb); | |
474 | *ppos = kiocb.ki_pos; | |
475 | return ret; | |
476 | } | |
477 | ||
478 | /* Do it by hand, with file-ops */ | |
479 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, | |
480 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) | |
481 | { | |
482 | struct iovec *vector = iov; | |
483 | ssize_t ret = 0; | |
484 | ||
485 | while (nr_segs > 0) { | |
486 | void __user *base; | |
487 | size_t len; | |
488 | ssize_t nr; | |
489 | ||
490 | base = vector->iov_base; | |
491 | len = vector->iov_len; | |
492 | vector++; | |
493 | nr_segs--; | |
494 | ||
495 | nr = fn(filp, base, len, ppos); | |
496 | ||
497 | if (nr < 0) { | |
498 | if (!ret) | |
499 | ret = nr; | |
500 | break; | |
501 | } | |
502 | ret += nr; | |
503 | if (nr != len) | |
504 | break; | |
505 | } | |
506 | ||
507 | return ret; | |
508 | } | |
509 | ||
510 | /* A write operation does a read from user space and vice versa */ | |
511 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) | |
512 | ||
513 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, | |
514 | unsigned long nr_segs, unsigned long fast_segs, | |
515 | struct iovec *fast_pointer, | |
516 | struct iovec **ret_pointer) | |
517 | { | |
518 | unsigned long seg; | |
519 | ssize_t ret; | |
520 | struct iovec *iov = fast_pointer; | |
521 | ||
522 | /* | |
523 | * SuS says "The readv() function *may* fail if the iovcnt argument | |
524 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
525 | * traditionally returned zero for zero segments, so... | |
526 | */ | |
527 | if (nr_segs == 0) { | |
528 | ret = 0; | |
529 | goto out; | |
530 | } | |
531 | ||
532 | /* | |
533 | * First get the "struct iovec" from user memory and | |
534 | * verify all the pointers | |
535 | */ | |
536 | if (nr_segs > UIO_MAXIOV) { | |
537 | ret = -EINVAL; | |
538 | goto out; | |
539 | } | |
540 | if (nr_segs > fast_segs) { | |
541 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); | |
542 | if (iov == NULL) { | |
543 | ret = -ENOMEM; | |
544 | goto out; | |
545 | } | |
546 | } | |
547 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { | |
548 | ret = -EFAULT; | |
549 | goto out; | |
550 | } | |
551 | ||
552 | /* | |
553 | * According to the Single Unix Specification we should return EINVAL | |
554 | * if an element length is < 0 when cast to ssize_t or if the | |
555 | * total length would overflow the ssize_t return value of the | |
556 | * system call. | |
557 | */ | |
558 | ret = 0; | |
559 | for (seg = 0; seg < nr_segs; seg++) { | |
560 | void __user *buf = iov[seg].iov_base; | |
561 | ssize_t len = (ssize_t)iov[seg].iov_len; | |
562 | ||
563 | /* see if we we're about to use an invalid len or if | |
564 | * it's about to overflow ssize_t */ | |
565 | if (len < 0 || (ret + len < ret)) { | |
566 | ret = -EINVAL; | |
567 | goto out; | |
568 | } | |
569 | if (unlikely(!access_ok(vrfy_dir(type), buf, len))) { | |
570 | ret = -EFAULT; | |
571 | goto out; | |
572 | } | |
573 | ||
574 | ret += len; | |
575 | } | |
576 | out: | |
577 | *ret_pointer = iov; | |
578 | return ret; | |
579 | } | |
580 | ||
581 | static ssize_t do_readv_writev(int type, struct file *file, | |
582 | const struct iovec __user * uvector, | |
583 | unsigned long nr_segs, loff_t *pos) | |
584 | { | |
585 | size_t tot_len; | |
586 | struct iovec iovstack[UIO_FASTIOV]; | |
587 | struct iovec *iov = iovstack; | |
588 | ssize_t ret; | |
589 | io_fn_t fn; | |
590 | iov_fn_t fnv; | |
591 | ||
592 | if (!file->f_op) { | |
593 | ret = -EINVAL; | |
594 | goto out; | |
595 | } | |
596 | ||
597 | ret = rw_copy_check_uvector(type, uvector, nr_segs, | |
598 | ARRAY_SIZE(iovstack), iovstack, &iov); | |
599 | if (ret <= 0) | |
600 | goto out; | |
601 | ||
602 | tot_len = ret; | |
603 | ret = rw_verify_area(type, file, pos, tot_len); | |
604 | if (ret < 0) | |
605 | goto out; | |
606 | ret = security_file_permission(file, type == READ ? MAY_READ : MAY_WRITE); | |
607 | if (ret) | |
608 | goto out; | |
609 | ||
610 | fnv = NULL; | |
611 | if (type == READ) { | |
612 | fn = file->f_op->read; | |
613 | fnv = file->f_op->aio_read; | |
614 | } else { | |
615 | fn = (io_fn_t)file->f_op->write; | |
616 | fnv = file->f_op->aio_write; | |
617 | } | |
618 | ||
619 | if (fnv) | |
620 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, | |
621 | pos, fnv); | |
622 | else | |
623 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); | |
624 | ||
625 | out: | |
626 | if (iov != iovstack) | |
627 | kfree(iov); | |
628 | if ((ret + (type == READ)) > 0) { | |
629 | if (type == READ) | |
630 | fsnotify_access(file->f_path.dentry); | |
631 | else | |
632 | fsnotify_modify(file->f_path.dentry); | |
633 | } | |
634 | return ret; | |
635 | } | |
636 | ||
637 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, | |
638 | unsigned long vlen, loff_t *pos) | |
639 | { | |
640 | if (!(file->f_mode & FMODE_READ)) | |
641 | return -EBADF; | |
642 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) | |
643 | return -EINVAL; | |
644 | ||
645 | return do_readv_writev(READ, file, vec, vlen, pos); | |
646 | } | |
647 | ||
648 | EXPORT_SYMBOL(vfs_readv); | |
649 | ||
650 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, | |
651 | unsigned long vlen, loff_t *pos) | |
652 | { | |
653 | if (!(file->f_mode & FMODE_WRITE)) | |
654 | return -EBADF; | |
655 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) | |
656 | return -EINVAL; | |
657 | ||
658 | return do_readv_writev(WRITE, file, vec, vlen, pos); | |
659 | } | |
660 | ||
661 | EXPORT_SYMBOL(vfs_writev); | |
662 | ||
663 | asmlinkage ssize_t | |
664 | sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen) | |
665 | { | |
666 | struct file *file; | |
667 | ssize_t ret = -EBADF; | |
668 | int fput_needed; | |
669 | ||
670 | file = fget_light(fd, &fput_needed); | |
671 | if (file) { | |
672 | loff_t pos = file_pos_read(file); | |
673 | ret = vfs_readv(file, vec, vlen, &pos); | |
674 | file_pos_write(file, pos); | |
675 | fput_light(file, fput_needed); | |
676 | } | |
677 | ||
678 | if (ret > 0) | |
679 | add_rchar(current, ret); | |
680 | inc_syscr(current); | |
681 | return ret; | |
682 | } | |
683 | ||
684 | asmlinkage ssize_t | |
685 | sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen) | |
686 | { | |
687 | struct file *file; | |
688 | ssize_t ret = -EBADF; | |
689 | int fput_needed; | |
690 | ||
691 | file = fget_light(fd, &fput_needed); | |
692 | if (file) { | |
693 | loff_t pos = file_pos_read(file); | |
694 | ret = vfs_writev(file, vec, vlen, &pos); | |
695 | file_pos_write(file, pos); | |
696 | fput_light(file, fput_needed); | |
697 | } | |
698 | ||
699 | if (ret > 0) | |
700 | add_wchar(current, ret); | |
701 | inc_syscw(current); | |
702 | return ret; | |
703 | } | |
704 | ||
705 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, | |
706 | size_t count, loff_t max) | |
707 | { | |
708 | struct file * in_file, * out_file; | |
709 | struct inode * in_inode, * out_inode; | |
710 | loff_t pos; | |
711 | ssize_t retval; | |
712 | int fput_needed_in, fput_needed_out, fl; | |
713 | ||
714 | /* | |
715 | * Get input file, and verify that it is ok.. | |
716 | */ | |
717 | retval = -EBADF; | |
718 | in_file = fget_light(in_fd, &fput_needed_in); | |
719 | if (!in_file) | |
720 | goto out; | |
721 | if (!(in_file->f_mode & FMODE_READ)) | |
722 | goto fput_in; | |
723 | retval = -EINVAL; | |
724 | in_inode = in_file->f_path.dentry->d_inode; | |
725 | if (!in_inode) | |
726 | goto fput_in; | |
727 | if (!in_file->f_op || !in_file->f_op->splice_read) | |
728 | goto fput_in; | |
729 | retval = -ESPIPE; | |
730 | if (!ppos) | |
731 | ppos = &in_file->f_pos; | |
732 | else | |
733 | if (!(in_file->f_mode & FMODE_PREAD)) | |
734 | goto fput_in; | |
735 | retval = rw_verify_area(READ, in_file, ppos, count); | |
736 | if (retval < 0) | |
737 | goto fput_in; | |
738 | count = retval; | |
739 | ||
740 | retval = security_file_permission (in_file, MAY_READ); | |
741 | if (retval) | |
742 | goto fput_in; | |
743 | ||
744 | /* | |
745 | * Get output file, and verify that it is ok.. | |
746 | */ | |
747 | retval = -EBADF; | |
748 | out_file = fget_light(out_fd, &fput_needed_out); | |
749 | if (!out_file) | |
750 | goto fput_in; | |
751 | if (!(out_file->f_mode & FMODE_WRITE)) | |
752 | goto fput_out; | |
753 | retval = -EINVAL; | |
754 | if (!out_file->f_op || !out_file->f_op->sendpage) | |
755 | goto fput_out; | |
756 | out_inode = out_file->f_path.dentry->d_inode; | |
757 | retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count); | |
758 | if (retval < 0) | |
759 | goto fput_out; | |
760 | count = retval; | |
761 | ||
762 | retval = security_file_permission (out_file, MAY_WRITE); | |
763 | if (retval) | |
764 | goto fput_out; | |
765 | ||
766 | if (!max) | |
767 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); | |
768 | ||
769 | pos = *ppos; | |
770 | retval = -EINVAL; | |
771 | if (unlikely(pos < 0)) | |
772 | goto fput_out; | |
773 | if (unlikely(pos + count > max)) { | |
774 | retval = -EOVERFLOW; | |
775 | if (pos >= max) | |
776 | goto fput_out; | |
777 | count = max - pos; | |
778 | } | |
779 | ||
780 | fl = 0; | |
781 | #if 0 | |
782 | /* | |
783 | * We need to debate whether we can enable this or not. The | |
784 | * man page documents EAGAIN return for the output at least, | |
785 | * and the application is arguably buggy if it doesn't expect | |
786 | * EAGAIN on a non-blocking file descriptor. | |
787 | */ | |
788 | if (in_file->f_flags & O_NONBLOCK) | |
789 | fl = SPLICE_F_NONBLOCK; | |
790 | #endif | |
791 | retval = do_splice_direct(in_file, ppos, out_file, count, fl); | |
792 | ||
793 | if (retval > 0) { | |
794 | add_rchar(current, retval); | |
795 | add_wchar(current, retval); | |
796 | } | |
797 | ||
798 | inc_syscr(current); | |
799 | inc_syscw(current); | |
800 | if (*ppos > max) | |
801 | retval = -EOVERFLOW; | |
802 | ||
803 | fput_out: | |
804 | fput_light(out_file, fput_needed_out); | |
805 | fput_in: | |
806 | fput_light(in_file, fput_needed_in); | |
807 | out: | |
808 | return retval; | |
809 | } | |
810 | ||
811 | asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count) | |
812 | { | |
813 | loff_t pos; | |
814 | off_t off; | |
815 | ssize_t ret; | |
816 | ||
817 | if (offset) { | |
818 | if (unlikely(get_user(off, offset))) | |
819 | return -EFAULT; | |
820 | pos = off; | |
821 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); | |
822 | if (unlikely(put_user(pos, offset))) | |
823 | return -EFAULT; | |
824 | return ret; | |
825 | } | |
826 | ||
827 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
828 | } | |
829 | ||
830 | asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count) | |
831 | { | |
832 | loff_t pos; | |
833 | ssize_t ret; | |
834 | ||
835 | if (offset) { | |
836 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) | |
837 | return -EFAULT; | |
838 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); | |
839 | if (unlikely(put_user(pos, offset))) | |
840 | return -EFAULT; | |
841 | return ret; | |
842 | } | |
843 | ||
844 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
845 | } |