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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 "read_write.h" | |
19 | ||
20 | #include <asm/uaccess.h> | |
21 | #include <asm/unistd.h> | |
22 | ||
23 | const struct file_operations generic_ro_fops = { | |
24 | .llseek = generic_file_llseek, | |
25 | .read = do_sync_read, | |
26 | .aio_read = generic_file_aio_read, | |
27 | .mmap = generic_file_readonly_mmap, | |
28 | .sendfile = generic_file_sendfile, | |
29 | }; | |
30 | ||
31 | EXPORT_SYMBOL(generic_ro_fops); | |
32 | ||
33 | loff_t generic_file_llseek(struct file *file, loff_t offset, int origin) | |
34 | { | |
35 | long long retval; | |
36 | struct inode *inode = file->f_mapping->host; | |
37 | ||
38 | mutex_lock(&inode->i_mutex); | |
39 | switch (origin) { | |
40 | case 2: | |
41 | offset += inode->i_size; | |
42 | break; | |
43 | case 1: | |
44 | offset += file->f_pos; | |
45 | } | |
46 | retval = -EINVAL; | |
47 | if (offset>=0 && offset<=inode->i_sb->s_maxbytes) { | |
48 | if (offset != file->f_pos) { | |
49 | file->f_pos = offset; | |
50 | file->f_version = 0; | |
51 | } | |
52 | retval = offset; | |
53 | } | |
54 | mutex_unlock(&inode->i_mutex); | |
55 | return retval; | |
56 | } | |
57 | ||
58 | EXPORT_SYMBOL(generic_file_llseek); | |
59 | ||
60 | loff_t remote_llseek(struct file *file, loff_t offset, int origin) | |
61 | { | |
62 | long long retval; | |
63 | ||
64 | lock_kernel(); | |
65 | switch (origin) { | |
66 | case 2: | |
67 | offset += i_size_read(file->f_dentry->d_inode); | |
68 | break; | |
69 | case 1: | |
70 | offset += file->f_pos; | |
71 | } | |
72 | retval = -EINVAL; | |
73 | if (offset>=0 && offset<=file->f_dentry->d_inode->i_sb->s_maxbytes) { | |
74 | if (offset != file->f_pos) { | |
75 | file->f_pos = offset; | |
76 | file->f_version = 0; | |
77 | } | |
78 | retval = offset; | |
79 | } | |
80 | unlock_kernel(); | |
81 | return retval; | |
82 | } | |
83 | EXPORT_SYMBOL(remote_llseek); | |
84 | ||
85 | loff_t no_llseek(struct file *file, loff_t offset, int origin) | |
86 | { | |
87 | return -ESPIPE; | |
88 | } | |
89 | EXPORT_SYMBOL(no_llseek); | |
90 | ||
91 | loff_t default_llseek(struct file *file, loff_t offset, int origin) | |
92 | { | |
93 | long long retval; | |
94 | ||
95 | lock_kernel(); | |
96 | switch (origin) { | |
97 | case 2: | |
98 | offset += i_size_read(file->f_dentry->d_inode); | |
99 | break; | |
100 | case 1: | |
101 | offset += file->f_pos; | |
102 | } | |
103 | retval = -EINVAL; | |
104 | if (offset >= 0) { | |
105 | if (offset != file->f_pos) { | |
106 | file->f_pos = offset; | |
107 | file->f_version = 0; | |
108 | } | |
109 | retval = offset; | |
110 | } | |
111 | unlock_kernel(); | |
112 | return retval; | |
113 | } | |
114 | EXPORT_SYMBOL(default_llseek); | |
115 | ||
116 | loff_t vfs_llseek(struct file *file, loff_t offset, int origin) | |
117 | { | |
118 | loff_t (*fn)(struct file *, loff_t, int); | |
119 | ||
120 | fn = no_llseek; | |
121 | if (file->f_mode & FMODE_LSEEK) { | |
122 | fn = default_llseek; | |
123 | if (file->f_op && file->f_op->llseek) | |
124 | fn = file->f_op->llseek; | |
125 | } | |
126 | return fn(file, offset, origin); | |
127 | } | |
128 | EXPORT_SYMBOL(vfs_llseek); | |
129 | ||
130 | asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin) | |
131 | { | |
132 | off_t retval; | |
133 | struct file * file; | |
134 | int fput_needed; | |
135 | ||
136 | retval = -EBADF; | |
137 | file = fget_light(fd, &fput_needed); | |
138 | if (!file) | |
139 | goto bad; | |
140 | ||
141 | retval = -EINVAL; | |
142 | if (origin <= 2) { | |
143 | loff_t res = vfs_llseek(file, offset, origin); | |
144 | retval = res; | |
145 | if (res != (loff_t)retval) | |
146 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ | |
147 | } | |
148 | fput_light(file, fput_needed); | |
149 | bad: | |
150 | return retval; | |
151 | } | |
152 | ||
153 | #ifdef __ARCH_WANT_SYS_LLSEEK | |
154 | asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high, | |
155 | unsigned long offset_low, loff_t __user * result, | |
156 | unsigned int origin) | |
157 | { | |
158 | int retval; | |
159 | struct file * file; | |
160 | loff_t offset; | |
161 | int fput_needed; | |
162 | ||
163 | retval = -EBADF; | |
164 | file = fget_light(fd, &fput_needed); | |
165 | if (!file) | |
166 | goto bad; | |
167 | ||
168 | retval = -EINVAL; | |
169 | if (origin > 2) | |
170 | goto out_putf; | |
171 | ||
172 | offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low, | |
173 | origin); | |
174 | ||
175 | retval = (int)offset; | |
176 | if (offset >= 0) { | |
177 | retval = -EFAULT; | |
178 | if (!copy_to_user(result, &offset, sizeof(offset))) | |
179 | retval = 0; | |
180 | } | |
181 | out_putf: | |
182 | fput_light(file, fput_needed); | |
183 | bad: | |
184 | return retval; | |
185 | } | |
186 | #endif | |
187 | ||
188 | /* | |
189 | * rw_verify_area doesn't like huge counts. We limit | |
190 | * them to something that fits in "int" so that others | |
191 | * won't have to do range checks all the time. | |
192 | */ | |
193 | #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK) | |
194 | ||
195 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) | |
196 | { | |
197 | struct inode *inode; | |
198 | loff_t pos; | |
199 | ||
200 | if (unlikely((ssize_t) count < 0)) | |
201 | goto Einval; | |
202 | pos = *ppos; | |
203 | if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) | |
204 | goto Einval; | |
205 | ||
206 | inode = file->f_dentry->d_inode; | |
207 | if (unlikely(inode->i_flock && MANDATORY_LOCK(inode))) { | |
208 | int retval = locks_mandatory_area( | |
209 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, | |
210 | inode, file, pos, count); | |
211 | if (retval < 0) | |
212 | return retval; | |
213 | } | |
214 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; | |
215 | ||
216 | Einval: | |
217 | return -EINVAL; | |
218 | } | |
219 | ||
220 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) | |
221 | { | |
222 | set_current_state(TASK_UNINTERRUPTIBLE); | |
223 | if (!kiocbIsKicked(iocb)) | |
224 | schedule(); | |
225 | else | |
226 | kiocbClearKicked(iocb); | |
227 | __set_current_state(TASK_RUNNING); | |
228 | } | |
229 | ||
230 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) | |
231 | { | |
232 | struct iovec iov = { .iov_base = buf, .iov_len = len }; | |
233 | struct kiocb kiocb; | |
234 | ssize_t ret; | |
235 | ||
236 | init_sync_kiocb(&kiocb, filp); | |
237 | kiocb.ki_pos = *ppos; | |
238 | kiocb.ki_left = len; | |
239 | ||
240 | for (;;) { | |
241 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); | |
242 | if (ret != -EIOCBRETRY) | |
243 | break; | |
244 | wait_on_retry_sync_kiocb(&kiocb); | |
245 | } | |
246 | ||
247 | if (-EIOCBQUEUED == ret) | |
248 | ret = wait_on_sync_kiocb(&kiocb); | |
249 | *ppos = kiocb.ki_pos; | |
250 | return ret; | |
251 | } | |
252 | ||
253 | EXPORT_SYMBOL(do_sync_read); | |
254 | ||
255 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) | |
256 | { | |
257 | ssize_t ret; | |
258 | ||
259 | if (!(file->f_mode & FMODE_READ)) | |
260 | return -EBADF; | |
261 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) | |
262 | return -EINVAL; | |
263 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) | |
264 | return -EFAULT; | |
265 | ||
266 | ret = rw_verify_area(READ, file, pos, count); | |
267 | if (ret >= 0) { | |
268 | count = ret; | |
269 | ret = security_file_permission (file, MAY_READ); | |
270 | if (!ret) { | |
271 | if (file->f_op->read) | |
272 | ret = file->f_op->read(file, buf, count, pos); | |
273 | else | |
274 | ret = do_sync_read(file, buf, count, pos); | |
275 | if (ret > 0) { | |
276 | fsnotify_access(file->f_dentry); | |
277 | current->rchar += ret; | |
278 | } | |
279 | current->syscr++; | |
280 | } | |
281 | } | |
282 | ||
283 | return ret; | |
284 | } | |
285 | ||
286 | EXPORT_SYMBOL(vfs_read); | |
287 | ||
288 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) | |
289 | { | |
290 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; | |
291 | struct kiocb kiocb; | |
292 | ssize_t ret; | |
293 | ||
294 | init_sync_kiocb(&kiocb, filp); | |
295 | kiocb.ki_pos = *ppos; | |
296 | kiocb.ki_left = len; | |
297 | ||
298 | for (;;) { | |
299 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); | |
300 | if (ret != -EIOCBRETRY) | |
301 | break; | |
302 | wait_on_retry_sync_kiocb(&kiocb); | |
303 | } | |
304 | ||
305 | if (-EIOCBQUEUED == ret) | |
306 | ret = wait_on_sync_kiocb(&kiocb); | |
307 | *ppos = kiocb.ki_pos; | |
308 | return ret; | |
309 | } | |
310 | ||
311 | EXPORT_SYMBOL(do_sync_write); | |
312 | ||
313 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) | |
314 | { | |
315 | ssize_t ret; | |
316 | ||
317 | if (!(file->f_mode & FMODE_WRITE)) | |
318 | return -EBADF; | |
319 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) | |
320 | return -EINVAL; | |
321 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) | |
322 | return -EFAULT; | |
323 | ||
324 | ret = rw_verify_area(WRITE, file, pos, count); | |
325 | if (ret >= 0) { | |
326 | count = ret; | |
327 | ret = security_file_permission (file, MAY_WRITE); | |
328 | if (!ret) { | |
329 | if (file->f_op->write) | |
330 | ret = file->f_op->write(file, buf, count, pos); | |
331 | else | |
332 | ret = do_sync_write(file, buf, count, pos); | |
333 | if (ret > 0) { | |
334 | fsnotify_modify(file->f_dentry); | |
335 | current->wchar += ret; | |
336 | } | |
337 | current->syscw++; | |
338 | } | |
339 | } | |
340 | ||
341 | return ret; | |
342 | } | |
343 | ||
344 | EXPORT_SYMBOL(vfs_write); | |
345 | ||
346 | static inline loff_t file_pos_read(struct file *file) | |
347 | { | |
348 | return file->f_pos; | |
349 | } | |
350 | ||
351 | static inline void file_pos_write(struct file *file, loff_t pos) | |
352 | { | |
353 | file->f_pos = pos; | |
354 | } | |
355 | ||
356 | asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count) | |
357 | { | |
358 | struct file *file; | |
359 | ssize_t ret = -EBADF; | |
360 | int fput_needed; | |
361 | ||
362 | file = fget_light(fd, &fput_needed); | |
363 | if (file) { | |
364 | loff_t pos = file_pos_read(file); | |
365 | ret = vfs_read(file, buf, count, &pos); | |
366 | file_pos_write(file, pos); | |
367 | fput_light(file, fput_needed); | |
368 | } | |
369 | ||
370 | return ret; | |
371 | } | |
372 | EXPORT_SYMBOL_GPL(sys_read); | |
373 | ||
374 | asmlinkage ssize_t sys_write(unsigned int fd, const 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_write(file, buf, count, &pos); | |
384 | file_pos_write(file, pos); | |
385 | fput_light(file, fput_needed); | |
386 | } | |
387 | ||
388 | return ret; | |
389 | } | |
390 | ||
391 | asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf, | |
392 | size_t count, loff_t pos) | |
393 | { | |
394 | struct file *file; | |
395 | ssize_t ret = -EBADF; | |
396 | int fput_needed; | |
397 | ||
398 | if (pos < 0) | |
399 | return -EINVAL; | |
400 | ||
401 | file = fget_light(fd, &fput_needed); | |
402 | if (file) { | |
403 | ret = -ESPIPE; | |
404 | if (file->f_mode & FMODE_PREAD) | |
405 | ret = vfs_read(file, buf, count, &pos); | |
406 | fput_light(file, fput_needed); | |
407 | } | |
408 | ||
409 | return ret; | |
410 | } | |
411 | ||
412 | asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf, | |
413 | size_t count, loff_t pos) | |
414 | { | |
415 | struct file *file; | |
416 | ssize_t ret = -EBADF; | |
417 | int fput_needed; | |
418 | ||
419 | if (pos < 0) | |
420 | return -EINVAL; | |
421 | ||
422 | file = fget_light(fd, &fput_needed); | |
423 | if (file) { | |
424 | ret = -ESPIPE; | |
425 | if (file->f_mode & FMODE_PWRITE) | |
426 | ret = vfs_write(file, buf, count, &pos); | |
427 | fput_light(file, fput_needed); | |
428 | } | |
429 | ||
430 | return ret; | |
431 | } | |
432 | ||
433 | /* | |
434 | * Reduce an iovec's length in-place. Return the resulting number of segments | |
435 | */ | |
436 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) | |
437 | { | |
438 | unsigned long seg = 0; | |
439 | size_t len = 0; | |
440 | ||
441 | while (seg < nr_segs) { | |
442 | seg++; | |
443 | if (len + iov->iov_len >= to) { | |
444 | iov->iov_len = to - len; | |
445 | break; | |
446 | } | |
447 | len += iov->iov_len; | |
448 | iov++; | |
449 | } | |
450 | return seg; | |
451 | } | |
452 | ||
453 | EXPORT_UNUSED_SYMBOL(iov_shorten); /* June 2006 */ | |
454 | ||
455 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, | |
456 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) | |
457 | { | |
458 | struct kiocb kiocb; | |
459 | ssize_t ret; | |
460 | ||
461 | init_sync_kiocb(&kiocb, filp); | |
462 | kiocb.ki_pos = *ppos; | |
463 | kiocb.ki_left = len; | |
464 | kiocb.ki_nbytes = len; | |
465 | ||
466 | for (;;) { | |
467 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); | |
468 | if (ret != -EIOCBRETRY) | |
469 | break; | |
470 | wait_on_retry_sync_kiocb(&kiocb); | |
471 | } | |
472 | ||
473 | if (ret == -EIOCBQUEUED) | |
474 | ret = wait_on_sync_kiocb(&kiocb); | |
475 | *ppos = kiocb.ki_pos; | |
476 | return ret; | |
477 | } | |
478 | ||
479 | /* Do it by hand, with file-ops */ | |
480 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, | |
481 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) | |
482 | { | |
483 | struct iovec *vector = iov; | |
484 | ssize_t ret = 0; | |
485 | ||
486 | while (nr_segs > 0) { | |
487 | void __user *base; | |
488 | size_t len; | |
489 | ssize_t nr; | |
490 | ||
491 | base = vector->iov_base; | |
492 | len = vector->iov_len; | |
493 | vector++; | |
494 | nr_segs--; | |
495 | ||
496 | nr = fn(filp, base, len, ppos); | |
497 | ||
498 | if (nr < 0) { | |
499 | if (!ret) | |
500 | ret = nr; | |
501 | break; | |
502 | } | |
503 | ret += nr; | |
504 | if (nr != len) | |
505 | break; | |
506 | } | |
507 | ||
508 | return ret; | |
509 | } | |
510 | ||
511 | /* A write operation does a read from user space and vice versa */ | |
512 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) | |
513 | ||
514 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, | |
515 | unsigned long nr_segs, unsigned long fast_segs, | |
516 | struct iovec *fast_pointer, | |
517 | struct iovec **ret_pointer) | |
518 | { | |
519 | unsigned long seg; | |
520 | ssize_t ret; | |
521 | struct iovec *iov = fast_pointer; | |
522 | ||
523 | /* | |
524 | * SuS says "The readv() function *may* fail if the iovcnt argument | |
525 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
526 | * traditionally returned zero for zero segments, so... | |
527 | */ | |
528 | if (nr_segs == 0) { | |
529 | ret = 0; | |
530 | goto out; | |
531 | } | |
532 | ||
533 | /* | |
534 | * First get the "struct iovec" from user memory and | |
535 | * verify all the pointers | |
536 | */ | |
537 | if (nr_segs > UIO_MAXIOV) { | |
538 | ret = -EINVAL; | |
539 | goto out; | |
540 | } | |
541 | if (nr_segs > fast_segs) { | |
542 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); | |
543 | if (iov == NULL) { | |
544 | ret = -ENOMEM; | |
545 | goto out; | |
546 | } | |
547 | } | |
548 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { | |
549 | ret = -EFAULT; | |
550 | goto out; | |
551 | } | |
552 | ||
553 | /* | |
554 | * According to the Single Unix Specification we should return EINVAL | |
555 | * if an element length is < 0 when cast to ssize_t or if the | |
556 | * total length would overflow the ssize_t return value of the | |
557 | * system call. | |
558 | */ | |
559 | ret = 0; | |
560 | for (seg = 0; seg < nr_segs; seg++) { | |
561 | void __user *buf = iov[seg].iov_base; | |
562 | ssize_t len = (ssize_t)iov[seg].iov_len; | |
563 | ||
564 | /* see if we we're about to use an invalid len or if | |
565 | * it's about to overflow ssize_t */ | |
566 | if (len < 0 || (ret + len < ret)) { | |
567 | ret = -EINVAL; | |
568 | goto out; | |
569 | } | |
570 | if (unlikely(!access_ok(vrfy_dir(type), buf, len))) { | |
571 | ret = -EFAULT; | |
572 | goto out; | |
573 | } | |
574 | ||
575 | ret += len; | |
576 | } | |
577 | out: | |
578 | *ret_pointer = iov; | |
579 | return ret; | |
580 | } | |
581 | ||
582 | static ssize_t do_readv_writev(int type, struct file *file, | |
583 | const struct iovec __user * uvector, | |
584 | unsigned long nr_segs, loff_t *pos) | |
585 | { | |
586 | size_t tot_len; | |
587 | struct iovec iovstack[UIO_FASTIOV]; | |
588 | struct iovec *iov = iovstack; | |
589 | ssize_t ret; | |
590 | io_fn_t fn; | |
591 | iov_fn_t fnv; | |
592 | ||
593 | if (!file->f_op) { | |
594 | ret = -EINVAL; | |
595 | goto out; | |
596 | } | |
597 | ||
598 | ret = rw_copy_check_uvector(type, uvector, nr_segs, | |
599 | ARRAY_SIZE(iovstack), iovstack, &iov); | |
600 | if (ret <= 0) | |
601 | goto out; | |
602 | ||
603 | tot_len = ret; | |
604 | ret = rw_verify_area(type, file, pos, tot_len); | |
605 | if (ret < 0) | |
606 | goto out; | |
607 | ret = security_file_permission(file, type == READ ? MAY_READ : MAY_WRITE); | |
608 | if (ret) | |
609 | goto out; | |
610 | ||
611 | fnv = NULL; | |
612 | if (type == READ) { | |
613 | fn = file->f_op->read; | |
614 | fnv = file->f_op->aio_read; | |
615 | } else { | |
616 | fn = (io_fn_t)file->f_op->write; | |
617 | fnv = file->f_op->aio_write; | |
618 | } | |
619 | ||
620 | if (fnv) | |
621 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, | |
622 | pos, fnv); | |
623 | else | |
624 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); | |
625 | ||
626 | out: | |
627 | if (iov != iovstack) | |
628 | kfree(iov); | |
629 | if ((ret + (type == READ)) > 0) { | |
630 | if (type == READ) | |
631 | fsnotify_access(file->f_dentry); | |
632 | else | |
633 | fsnotify_modify(file->f_dentry); | |
634 | } | |
635 | return ret; | |
636 | } | |
637 | ||
638 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, | |
639 | unsigned long vlen, loff_t *pos) | |
640 | { | |
641 | if (!(file->f_mode & FMODE_READ)) | |
642 | return -EBADF; | |
643 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) | |
644 | return -EINVAL; | |
645 | ||
646 | return do_readv_writev(READ, file, vec, vlen, pos); | |
647 | } | |
648 | ||
649 | EXPORT_SYMBOL(vfs_readv); | |
650 | ||
651 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, | |
652 | unsigned long vlen, loff_t *pos) | |
653 | { | |
654 | if (!(file->f_mode & FMODE_WRITE)) | |
655 | return -EBADF; | |
656 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) | |
657 | return -EINVAL; | |
658 | ||
659 | return do_readv_writev(WRITE, file, vec, vlen, pos); | |
660 | } | |
661 | ||
662 | EXPORT_SYMBOL(vfs_writev); | |
663 | ||
664 | asmlinkage ssize_t | |
665 | sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen) | |
666 | { | |
667 | struct file *file; | |
668 | ssize_t ret = -EBADF; | |
669 | int fput_needed; | |
670 | ||
671 | file = fget_light(fd, &fput_needed); | |
672 | if (file) { | |
673 | loff_t pos = file_pos_read(file); | |
674 | ret = vfs_readv(file, vec, vlen, &pos); | |
675 | file_pos_write(file, pos); | |
676 | fput_light(file, fput_needed); | |
677 | } | |
678 | ||
679 | if (ret > 0) | |
680 | current->rchar += ret; | |
681 | current->syscr++; | |
682 | return ret; | |
683 | } | |
684 | ||
685 | asmlinkage ssize_t | |
686 | sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen) | |
687 | { | |
688 | struct file *file; | |
689 | ssize_t ret = -EBADF; | |
690 | int fput_needed; | |
691 | ||
692 | file = fget_light(fd, &fput_needed); | |
693 | if (file) { | |
694 | loff_t pos = file_pos_read(file); | |
695 | ret = vfs_writev(file, vec, vlen, &pos); | |
696 | file_pos_write(file, pos); | |
697 | fput_light(file, fput_needed); | |
698 | } | |
699 | ||
700 | if (ret > 0) | |
701 | current->wchar += ret; | |
702 | current->syscw++; | |
703 | return ret; | |
704 | } | |
705 | ||
706 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, | |
707 | size_t count, loff_t max) | |
708 | { | |
709 | struct file * in_file, * out_file; | |
710 | struct inode * in_inode, * out_inode; | |
711 | loff_t pos; | |
712 | ssize_t retval; | |
713 | int fput_needed_in, fput_needed_out; | |
714 | ||
715 | /* | |
716 | * Get input file, and verify that it is ok.. | |
717 | */ | |
718 | retval = -EBADF; | |
719 | in_file = fget_light(in_fd, &fput_needed_in); | |
720 | if (!in_file) | |
721 | goto out; | |
722 | if (!(in_file->f_mode & FMODE_READ)) | |
723 | goto fput_in; | |
724 | retval = -EINVAL; | |
725 | in_inode = in_file->f_dentry->d_inode; | |
726 | if (!in_inode) | |
727 | goto fput_in; | |
728 | if (!in_file->f_op || !in_file->f_op->sendfile) | |
729 | goto fput_in; | |
730 | retval = -ESPIPE; | |
731 | if (!ppos) | |
732 | ppos = &in_file->f_pos; | |
733 | else | |
734 | if (!(in_file->f_mode & FMODE_PREAD)) | |
735 | goto fput_in; | |
736 | retval = rw_verify_area(READ, in_file, ppos, count); | |
737 | if (retval < 0) | |
738 | goto fput_in; | |
739 | count = retval; | |
740 | ||
741 | retval = security_file_permission (in_file, MAY_READ); | |
742 | if (retval) | |
743 | goto fput_in; | |
744 | ||
745 | /* | |
746 | * Get output file, and verify that it is ok.. | |
747 | */ | |
748 | retval = -EBADF; | |
749 | out_file = fget_light(out_fd, &fput_needed_out); | |
750 | if (!out_file) | |
751 | goto fput_in; | |
752 | if (!(out_file->f_mode & FMODE_WRITE)) | |
753 | goto fput_out; | |
754 | retval = -EINVAL; | |
755 | if (!out_file->f_op || !out_file->f_op->sendpage) | |
756 | goto fput_out; | |
757 | out_inode = out_file->f_dentry->d_inode; | |
758 | retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count); | |
759 | if (retval < 0) | |
760 | goto fput_out; | |
761 | count = retval; | |
762 | ||
763 | retval = security_file_permission (out_file, MAY_WRITE); | |
764 | if (retval) | |
765 | goto fput_out; | |
766 | ||
767 | if (!max) | |
768 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); | |
769 | ||
770 | pos = *ppos; | |
771 | retval = -EINVAL; | |
772 | if (unlikely(pos < 0)) | |
773 | goto fput_out; | |
774 | if (unlikely(pos + count > max)) { | |
775 | retval = -EOVERFLOW; | |
776 | if (pos >= max) | |
777 | goto fput_out; | |
778 | count = max - pos; | |
779 | } | |
780 | ||
781 | retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file); | |
782 | ||
783 | if (retval > 0) { | |
784 | current->rchar += retval; | |
785 | current->wchar += retval; | |
786 | } | |
787 | current->syscr++; | |
788 | current->syscw++; | |
789 | ||
790 | if (*ppos > max) | |
791 | retval = -EOVERFLOW; | |
792 | ||
793 | fput_out: | |
794 | fput_light(out_file, fput_needed_out); | |
795 | fput_in: | |
796 | fput_light(in_file, fput_needed_in); | |
797 | out: | |
798 | return retval; | |
799 | } | |
800 | ||
801 | asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count) | |
802 | { | |
803 | loff_t pos; | |
804 | off_t off; | |
805 | ssize_t ret; | |
806 | ||
807 | if (offset) { | |
808 | if (unlikely(get_user(off, offset))) | |
809 | return -EFAULT; | |
810 | pos = off; | |
811 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); | |
812 | if (unlikely(put_user(pos, offset))) | |
813 | return -EFAULT; | |
814 | return ret; | |
815 | } | |
816 | ||
817 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
818 | } | |
819 | ||
820 | asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count) | |
821 | { | |
822 | loff_t pos; | |
823 | ssize_t ret; | |
824 | ||
825 | if (offset) { | |
826 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) | |
827 | return -EFAULT; | |
828 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); | |
829 | if (unlikely(put_user(pos, offset))) | |
830 | return -EFAULT; | |
831 | return ret; | |
832 | } | |
833 | ||
834 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
835 | } |