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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 | /** | |
101 | * noop_llseek - No Operation Performed llseek implementation | |
102 | * @file: file structure to seek on | |
103 | * @offset: file offset to seek to | |
104 | * @origin: type of seek | |
105 | * | |
106 | * This is an implementation of ->llseek useable for the rare special case when | |
107 | * userspace expects the seek to succeed but the (device) file is actually not | |
108 | * able to perform the seek. In this case you use noop_llseek() instead of | |
109 | * falling back to the default implementation of ->llseek. | |
110 | */ | |
111 | loff_t noop_llseek(struct file *file, loff_t offset, int origin) | |
112 | { | |
113 | return file->f_pos; | |
114 | } | |
115 | EXPORT_SYMBOL(noop_llseek); | |
116 | ||
117 | loff_t no_llseek(struct file *file, loff_t offset, int origin) | |
118 | { | |
119 | return -ESPIPE; | |
120 | } | |
121 | EXPORT_SYMBOL(no_llseek); | |
122 | ||
123 | loff_t default_llseek(struct file *file, loff_t offset, int origin) | |
124 | { | |
125 | loff_t retval; | |
126 | ||
127 | lock_kernel(); | |
128 | switch (origin) { | |
129 | case SEEK_END: | |
130 | offset += i_size_read(file->f_path.dentry->d_inode); | |
131 | break; | |
132 | case SEEK_CUR: | |
133 | if (offset == 0) { | |
134 | retval = file->f_pos; | |
135 | goto out; | |
136 | } | |
137 | offset += file->f_pos; | |
138 | } | |
139 | retval = -EINVAL; | |
140 | if (offset >= 0) { | |
141 | if (offset != file->f_pos) { | |
142 | file->f_pos = offset; | |
143 | file->f_version = 0; | |
144 | } | |
145 | retval = offset; | |
146 | } | |
147 | out: | |
148 | unlock_kernel(); | |
149 | return retval; | |
150 | } | |
151 | EXPORT_SYMBOL(default_llseek); | |
152 | ||
153 | loff_t vfs_llseek(struct file *file, loff_t offset, int origin) | |
154 | { | |
155 | loff_t (*fn)(struct file *, loff_t, int); | |
156 | ||
157 | fn = no_llseek; | |
158 | if (file->f_mode & FMODE_LSEEK) { | |
159 | fn = default_llseek; | |
160 | if (file->f_op && file->f_op->llseek) | |
161 | fn = file->f_op->llseek; | |
162 | } | |
163 | return fn(file, offset, origin); | |
164 | } | |
165 | EXPORT_SYMBOL(vfs_llseek); | |
166 | ||
167 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, origin) | |
168 | { | |
169 | off_t retval; | |
170 | struct file * file; | |
171 | int fput_needed; | |
172 | ||
173 | retval = -EBADF; | |
174 | file = fget_light(fd, &fput_needed); | |
175 | if (!file) | |
176 | goto bad; | |
177 | ||
178 | retval = -EINVAL; | |
179 | if (origin <= SEEK_MAX) { | |
180 | loff_t res = vfs_llseek(file, offset, origin); | |
181 | retval = res; | |
182 | if (res != (loff_t)retval) | |
183 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ | |
184 | } | |
185 | fput_light(file, fput_needed); | |
186 | bad: | |
187 | return retval; | |
188 | } | |
189 | ||
190 | #ifdef __ARCH_WANT_SYS_LLSEEK | |
191 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, | |
192 | unsigned long, offset_low, loff_t __user *, result, | |
193 | unsigned int, origin) | |
194 | { | |
195 | int retval; | |
196 | struct file * file; | |
197 | loff_t offset; | |
198 | int fput_needed; | |
199 | ||
200 | retval = -EBADF; | |
201 | file = fget_light(fd, &fput_needed); | |
202 | if (!file) | |
203 | goto bad; | |
204 | ||
205 | retval = -EINVAL; | |
206 | if (origin > SEEK_MAX) | |
207 | goto out_putf; | |
208 | ||
209 | offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low, | |
210 | origin); | |
211 | ||
212 | retval = (int)offset; | |
213 | if (offset >= 0) { | |
214 | retval = -EFAULT; | |
215 | if (!copy_to_user(result, &offset, sizeof(offset))) | |
216 | retval = 0; | |
217 | } | |
218 | out_putf: | |
219 | fput_light(file, fput_needed); | |
220 | bad: | |
221 | return retval; | |
222 | } | |
223 | #endif | |
224 | ||
225 | /* | |
226 | * rw_verify_area doesn't like huge counts. We limit | |
227 | * them to something that fits in "int" so that others | |
228 | * won't have to do range checks all the time. | |
229 | */ | |
230 | #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK) | |
231 | ||
232 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) | |
233 | { | |
234 | struct inode *inode; | |
235 | loff_t pos; | |
236 | int retval = -EINVAL; | |
237 | ||
238 | inode = file->f_path.dentry->d_inode; | |
239 | if (unlikely((ssize_t) count < 0)) | |
240 | return retval; | |
241 | pos = *ppos; | |
242 | if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) | |
243 | return retval; | |
244 | ||
245 | if (unlikely(inode->i_flock && mandatory_lock(inode))) { | |
246 | retval = locks_mandatory_area( | |
247 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, | |
248 | inode, file, pos, count); | |
249 | if (retval < 0) | |
250 | return retval; | |
251 | } | |
252 | retval = security_file_permission(file, | |
253 | read_write == READ ? MAY_READ : MAY_WRITE); | |
254 | if (retval) | |
255 | return retval; | |
256 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; | |
257 | } | |
258 | ||
259 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) | |
260 | { | |
261 | set_current_state(TASK_UNINTERRUPTIBLE); | |
262 | if (!kiocbIsKicked(iocb)) | |
263 | schedule(); | |
264 | else | |
265 | kiocbClearKicked(iocb); | |
266 | __set_current_state(TASK_RUNNING); | |
267 | } | |
268 | ||
269 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) | |
270 | { | |
271 | struct iovec iov = { .iov_base = buf, .iov_len = len }; | |
272 | struct kiocb kiocb; | |
273 | ssize_t ret; | |
274 | ||
275 | init_sync_kiocb(&kiocb, filp); | |
276 | kiocb.ki_pos = *ppos; | |
277 | kiocb.ki_left = len; | |
278 | kiocb.ki_nbytes = len; | |
279 | ||
280 | for (;;) { | |
281 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); | |
282 | if (ret != -EIOCBRETRY) | |
283 | break; | |
284 | wait_on_retry_sync_kiocb(&kiocb); | |
285 | } | |
286 | ||
287 | if (-EIOCBQUEUED == ret) | |
288 | ret = wait_on_sync_kiocb(&kiocb); | |
289 | *ppos = kiocb.ki_pos; | |
290 | return ret; | |
291 | } | |
292 | ||
293 | EXPORT_SYMBOL(do_sync_read); | |
294 | ||
295 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) | |
296 | { | |
297 | ssize_t ret; | |
298 | ||
299 | if (!(file->f_mode & FMODE_READ)) | |
300 | return -EBADF; | |
301 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) | |
302 | return -EINVAL; | |
303 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) | |
304 | return -EFAULT; | |
305 | ||
306 | ret = rw_verify_area(READ, file, pos, count); | |
307 | if (ret >= 0) { | |
308 | count = ret; | |
309 | if (file->f_op->read) | |
310 | ret = file->f_op->read(file, buf, count, pos); | |
311 | else | |
312 | ret = do_sync_read(file, buf, count, pos); | |
313 | if (ret > 0) { | |
314 | fsnotify_access(file->f_path.dentry); | |
315 | add_rchar(current, ret); | |
316 | } | |
317 | inc_syscr(current); | |
318 | } | |
319 | ||
320 | return ret; | |
321 | } | |
322 | ||
323 | EXPORT_SYMBOL(vfs_read); | |
324 | ||
325 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) | |
326 | { | |
327 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; | |
328 | struct kiocb kiocb; | |
329 | ssize_t ret; | |
330 | ||
331 | init_sync_kiocb(&kiocb, filp); | |
332 | kiocb.ki_pos = *ppos; | |
333 | kiocb.ki_left = len; | |
334 | kiocb.ki_nbytes = len; | |
335 | ||
336 | for (;;) { | |
337 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); | |
338 | if (ret != -EIOCBRETRY) | |
339 | break; | |
340 | wait_on_retry_sync_kiocb(&kiocb); | |
341 | } | |
342 | ||
343 | if (-EIOCBQUEUED == ret) | |
344 | ret = wait_on_sync_kiocb(&kiocb); | |
345 | *ppos = kiocb.ki_pos; | |
346 | return ret; | |
347 | } | |
348 | ||
349 | EXPORT_SYMBOL(do_sync_write); | |
350 | ||
351 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) | |
352 | { | |
353 | ssize_t ret; | |
354 | ||
355 | if (!(file->f_mode & FMODE_WRITE)) | |
356 | return -EBADF; | |
357 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) | |
358 | return -EINVAL; | |
359 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) | |
360 | return -EFAULT; | |
361 | ||
362 | ret = rw_verify_area(WRITE, file, pos, count); | |
363 | if (ret >= 0) { | |
364 | count = ret; | |
365 | if (file->f_op->write) | |
366 | ret = file->f_op->write(file, buf, count, pos); | |
367 | else | |
368 | ret = do_sync_write(file, buf, count, pos); | |
369 | if (ret > 0) { | |
370 | fsnotify_modify(file->f_path.dentry); | |
371 | add_wchar(current, ret); | |
372 | } | |
373 | inc_syscw(current); | |
374 | } | |
375 | ||
376 | return ret; | |
377 | } | |
378 | ||
379 | EXPORT_SYMBOL(vfs_write); | |
380 | ||
381 | static inline loff_t file_pos_read(struct file *file) | |
382 | { | |
383 | return file->f_pos; | |
384 | } | |
385 | ||
386 | static inline void file_pos_write(struct file *file, loff_t pos) | |
387 | { | |
388 | file->f_pos = pos; | |
389 | } | |
390 | ||
391 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) | |
392 | { | |
393 | struct file *file; | |
394 | ssize_t ret = -EBADF; | |
395 | int fput_needed; | |
396 | ||
397 | file = fget_light(fd, &fput_needed); | |
398 | if (file) { | |
399 | loff_t pos = file_pos_read(file); | |
400 | ret = vfs_read(file, buf, count, &pos); | |
401 | file_pos_write(file, pos); | |
402 | fput_light(file, fput_needed); | |
403 | } | |
404 | ||
405 | return ret; | |
406 | } | |
407 | ||
408 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, | |
409 | size_t, count) | |
410 | { | |
411 | struct file *file; | |
412 | ssize_t ret = -EBADF; | |
413 | int fput_needed; | |
414 | ||
415 | file = fget_light(fd, &fput_needed); | |
416 | if (file) { | |
417 | loff_t pos = file_pos_read(file); | |
418 | ret = vfs_write(file, buf, count, &pos); | |
419 | file_pos_write(file, pos); | |
420 | fput_light(file, fput_needed); | |
421 | } | |
422 | ||
423 | return ret; | |
424 | } | |
425 | ||
426 | SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf, | |
427 | size_t count, loff_t pos) | |
428 | { | |
429 | struct file *file; | |
430 | ssize_t ret = -EBADF; | |
431 | int fput_needed; | |
432 | ||
433 | if (pos < 0) | |
434 | return -EINVAL; | |
435 | ||
436 | file = fget_light(fd, &fput_needed); | |
437 | if (file) { | |
438 | ret = -ESPIPE; | |
439 | if (file->f_mode & FMODE_PREAD) | |
440 | ret = vfs_read(file, buf, count, &pos); | |
441 | fput_light(file, fput_needed); | |
442 | } | |
443 | ||
444 | return ret; | |
445 | } | |
446 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
447 | asmlinkage long SyS_pread64(long fd, long buf, long count, loff_t pos) | |
448 | { | |
449 | return SYSC_pread64((unsigned int) fd, (char __user *) buf, | |
450 | (size_t) count, pos); | |
451 | } | |
452 | SYSCALL_ALIAS(sys_pread64, SyS_pread64); | |
453 | #endif | |
454 | ||
455 | SYSCALL_DEFINE(pwrite64)(unsigned int fd, const char __user *buf, | |
456 | size_t count, loff_t pos) | |
457 | { | |
458 | struct file *file; | |
459 | ssize_t ret = -EBADF; | |
460 | int fput_needed; | |
461 | ||
462 | if (pos < 0) | |
463 | return -EINVAL; | |
464 | ||
465 | file = fget_light(fd, &fput_needed); | |
466 | if (file) { | |
467 | ret = -ESPIPE; | |
468 | if (file->f_mode & FMODE_PWRITE) | |
469 | ret = vfs_write(file, buf, count, &pos); | |
470 | fput_light(file, fput_needed); | |
471 | } | |
472 | ||
473 | return ret; | |
474 | } | |
475 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
476 | asmlinkage long SyS_pwrite64(long fd, long buf, long count, loff_t pos) | |
477 | { | |
478 | return SYSC_pwrite64((unsigned int) fd, (const char __user *) buf, | |
479 | (size_t) count, pos); | |
480 | } | |
481 | SYSCALL_ALIAS(sys_pwrite64, SyS_pwrite64); | |
482 | #endif | |
483 | ||
484 | /* | |
485 | * Reduce an iovec's length in-place. Return the resulting number of segments | |
486 | */ | |
487 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) | |
488 | { | |
489 | unsigned long seg = 0; | |
490 | size_t len = 0; | |
491 | ||
492 | while (seg < nr_segs) { | |
493 | seg++; | |
494 | if (len + iov->iov_len >= to) { | |
495 | iov->iov_len = to - len; | |
496 | break; | |
497 | } | |
498 | len += iov->iov_len; | |
499 | iov++; | |
500 | } | |
501 | return seg; | |
502 | } | |
503 | EXPORT_SYMBOL(iov_shorten); | |
504 | ||
505 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, | |
506 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) | |
507 | { | |
508 | struct kiocb kiocb; | |
509 | ssize_t ret; | |
510 | ||
511 | init_sync_kiocb(&kiocb, filp); | |
512 | kiocb.ki_pos = *ppos; | |
513 | kiocb.ki_left = len; | |
514 | kiocb.ki_nbytes = len; | |
515 | ||
516 | for (;;) { | |
517 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); | |
518 | if (ret != -EIOCBRETRY) | |
519 | break; | |
520 | wait_on_retry_sync_kiocb(&kiocb); | |
521 | } | |
522 | ||
523 | if (ret == -EIOCBQUEUED) | |
524 | ret = wait_on_sync_kiocb(&kiocb); | |
525 | *ppos = kiocb.ki_pos; | |
526 | return ret; | |
527 | } | |
528 | ||
529 | /* Do it by hand, with file-ops */ | |
530 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, | |
531 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) | |
532 | { | |
533 | struct iovec *vector = iov; | |
534 | ssize_t ret = 0; | |
535 | ||
536 | while (nr_segs > 0) { | |
537 | void __user *base; | |
538 | size_t len; | |
539 | ssize_t nr; | |
540 | ||
541 | base = vector->iov_base; | |
542 | len = vector->iov_len; | |
543 | vector++; | |
544 | nr_segs--; | |
545 | ||
546 | nr = fn(filp, base, len, ppos); | |
547 | ||
548 | if (nr < 0) { | |
549 | if (!ret) | |
550 | ret = nr; | |
551 | break; | |
552 | } | |
553 | ret += nr; | |
554 | if (nr != len) | |
555 | break; | |
556 | } | |
557 | ||
558 | return ret; | |
559 | } | |
560 | ||
561 | /* A write operation does a read from user space and vice versa */ | |
562 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) | |
563 | ||
564 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, | |
565 | unsigned long nr_segs, unsigned long fast_segs, | |
566 | struct iovec *fast_pointer, | |
567 | struct iovec **ret_pointer) | |
568 | { | |
569 | unsigned long seg; | |
570 | ssize_t ret; | |
571 | struct iovec *iov = fast_pointer; | |
572 | ||
573 | /* | |
574 | * SuS says "The readv() function *may* fail if the iovcnt argument | |
575 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
576 | * traditionally returned zero for zero segments, so... | |
577 | */ | |
578 | if (nr_segs == 0) { | |
579 | ret = 0; | |
580 | goto out; | |
581 | } | |
582 | ||
583 | /* | |
584 | * First get the "struct iovec" from user memory and | |
585 | * verify all the pointers | |
586 | */ | |
587 | if (nr_segs > UIO_MAXIOV) { | |
588 | ret = -EINVAL; | |
589 | goto out; | |
590 | } | |
591 | if (nr_segs > fast_segs) { | |
592 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); | |
593 | if (iov == NULL) { | |
594 | ret = -ENOMEM; | |
595 | goto out; | |
596 | } | |
597 | } | |
598 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { | |
599 | ret = -EFAULT; | |
600 | goto out; | |
601 | } | |
602 | ||
603 | /* | |
604 | * According to the Single Unix Specification we should return EINVAL | |
605 | * if an element length is < 0 when cast to ssize_t or if the | |
606 | * total length would overflow the ssize_t return value of the | |
607 | * system call. | |
608 | */ | |
609 | ret = 0; | |
610 | for (seg = 0; seg < nr_segs; seg++) { | |
611 | void __user *buf = iov[seg].iov_base; | |
612 | ssize_t len = (ssize_t)iov[seg].iov_len; | |
613 | ||
614 | /* see if we we're about to use an invalid len or if | |
615 | * it's about to overflow ssize_t */ | |
616 | if (len < 0 || (ret + len < ret)) { | |
617 | ret = -EINVAL; | |
618 | goto out; | |
619 | } | |
620 | if (unlikely(!access_ok(vrfy_dir(type), buf, len))) { | |
621 | ret = -EFAULT; | |
622 | goto out; | |
623 | } | |
624 | ||
625 | ret += len; | |
626 | } | |
627 | out: | |
628 | *ret_pointer = iov; | |
629 | return ret; | |
630 | } | |
631 | ||
632 | static ssize_t do_readv_writev(int type, struct file *file, | |
633 | const struct iovec __user * uvector, | |
634 | unsigned long nr_segs, loff_t *pos) | |
635 | { | |
636 | size_t tot_len; | |
637 | struct iovec iovstack[UIO_FASTIOV]; | |
638 | struct iovec *iov = iovstack; | |
639 | ssize_t ret; | |
640 | io_fn_t fn; | |
641 | iov_fn_t fnv; | |
642 | ||
643 | if (!file->f_op) { | |
644 | ret = -EINVAL; | |
645 | goto out; | |
646 | } | |
647 | ||
648 | ret = rw_copy_check_uvector(type, uvector, nr_segs, | |
649 | ARRAY_SIZE(iovstack), iovstack, &iov); | |
650 | if (ret <= 0) | |
651 | goto out; | |
652 | ||
653 | tot_len = ret; | |
654 | ret = rw_verify_area(type, file, pos, tot_len); | |
655 | if (ret < 0) | |
656 | goto out; | |
657 | ||
658 | fnv = NULL; | |
659 | if (type == READ) { | |
660 | fn = file->f_op->read; | |
661 | fnv = file->f_op->aio_read; | |
662 | } else { | |
663 | fn = (io_fn_t)file->f_op->write; | |
664 | fnv = file->f_op->aio_write; | |
665 | } | |
666 | ||
667 | if (fnv) | |
668 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, | |
669 | pos, fnv); | |
670 | else | |
671 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); | |
672 | ||
673 | out: | |
674 | if (iov != iovstack) | |
675 | kfree(iov); | |
676 | if ((ret + (type == READ)) > 0) { | |
677 | if (type == READ) | |
678 | fsnotify_access(file->f_path.dentry); | |
679 | else | |
680 | fsnotify_modify(file->f_path.dentry); | |
681 | } | |
682 | return ret; | |
683 | } | |
684 | ||
685 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, | |
686 | unsigned long vlen, loff_t *pos) | |
687 | { | |
688 | if (!(file->f_mode & FMODE_READ)) | |
689 | return -EBADF; | |
690 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) | |
691 | return -EINVAL; | |
692 | ||
693 | return do_readv_writev(READ, file, vec, vlen, pos); | |
694 | } | |
695 | ||
696 | EXPORT_SYMBOL(vfs_readv); | |
697 | ||
698 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, | |
699 | unsigned long vlen, loff_t *pos) | |
700 | { | |
701 | if (!(file->f_mode & FMODE_WRITE)) | |
702 | return -EBADF; | |
703 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) | |
704 | return -EINVAL; | |
705 | ||
706 | return do_readv_writev(WRITE, file, vec, vlen, pos); | |
707 | } | |
708 | ||
709 | EXPORT_SYMBOL(vfs_writev); | |
710 | ||
711 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, | |
712 | unsigned long, vlen) | |
713 | { | |
714 | struct file *file; | |
715 | ssize_t ret = -EBADF; | |
716 | int fput_needed; | |
717 | ||
718 | file = fget_light(fd, &fput_needed); | |
719 | if (file) { | |
720 | loff_t pos = file_pos_read(file); | |
721 | ret = vfs_readv(file, vec, vlen, &pos); | |
722 | file_pos_write(file, pos); | |
723 | fput_light(file, fput_needed); | |
724 | } | |
725 | ||
726 | if (ret > 0) | |
727 | add_rchar(current, ret); | |
728 | inc_syscr(current); | |
729 | return ret; | |
730 | } | |
731 | ||
732 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, | |
733 | unsigned long, vlen) | |
734 | { | |
735 | struct file *file; | |
736 | ssize_t ret = -EBADF; | |
737 | int fput_needed; | |
738 | ||
739 | file = fget_light(fd, &fput_needed); | |
740 | if (file) { | |
741 | loff_t pos = file_pos_read(file); | |
742 | ret = vfs_writev(file, vec, vlen, &pos); | |
743 | file_pos_write(file, pos); | |
744 | fput_light(file, fput_needed); | |
745 | } | |
746 | ||
747 | if (ret > 0) | |
748 | add_wchar(current, ret); | |
749 | inc_syscw(current); | |
750 | return ret; | |
751 | } | |
752 | ||
753 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) | |
754 | { | |
755 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) | |
756 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; | |
757 | } | |
758 | ||
759 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, | |
760 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) | |
761 | { | |
762 | loff_t pos = pos_from_hilo(pos_h, pos_l); | |
763 | struct file *file; | |
764 | ssize_t ret = -EBADF; | |
765 | int fput_needed; | |
766 | ||
767 | if (pos < 0) | |
768 | return -EINVAL; | |
769 | ||
770 | file = fget_light(fd, &fput_needed); | |
771 | if (file) { | |
772 | ret = -ESPIPE; | |
773 | if (file->f_mode & FMODE_PREAD) | |
774 | ret = vfs_readv(file, vec, vlen, &pos); | |
775 | fput_light(file, fput_needed); | |
776 | } | |
777 | ||
778 | if (ret > 0) | |
779 | add_rchar(current, ret); | |
780 | inc_syscr(current); | |
781 | return ret; | |
782 | } | |
783 | ||
784 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, | |
785 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) | |
786 | { | |
787 | loff_t pos = pos_from_hilo(pos_h, pos_l); | |
788 | struct file *file; | |
789 | ssize_t ret = -EBADF; | |
790 | int fput_needed; | |
791 | ||
792 | if (pos < 0) | |
793 | return -EINVAL; | |
794 | ||
795 | file = fget_light(fd, &fput_needed); | |
796 | if (file) { | |
797 | ret = -ESPIPE; | |
798 | if (file->f_mode & FMODE_PWRITE) | |
799 | ret = vfs_writev(file, vec, vlen, &pos); | |
800 | fput_light(file, fput_needed); | |
801 | } | |
802 | ||
803 | if (ret > 0) | |
804 | add_wchar(current, ret); | |
805 | inc_syscw(current); | |
806 | return ret; | |
807 | } | |
808 | ||
809 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, | |
810 | size_t count, loff_t max) | |
811 | { | |
812 | struct file * in_file, * out_file; | |
813 | struct inode * in_inode, * out_inode; | |
814 | loff_t pos; | |
815 | ssize_t retval; | |
816 | int fput_needed_in, fput_needed_out, fl; | |
817 | ||
818 | /* | |
819 | * Get input file, and verify that it is ok.. | |
820 | */ | |
821 | retval = -EBADF; | |
822 | in_file = fget_light(in_fd, &fput_needed_in); | |
823 | if (!in_file) | |
824 | goto out; | |
825 | if (!(in_file->f_mode & FMODE_READ)) | |
826 | goto fput_in; | |
827 | retval = -ESPIPE; | |
828 | if (!ppos) | |
829 | ppos = &in_file->f_pos; | |
830 | else | |
831 | if (!(in_file->f_mode & FMODE_PREAD)) | |
832 | goto fput_in; | |
833 | retval = rw_verify_area(READ, in_file, ppos, count); | |
834 | if (retval < 0) | |
835 | goto fput_in; | |
836 | count = retval; | |
837 | ||
838 | /* | |
839 | * Get output file, and verify that it is ok.. | |
840 | */ | |
841 | retval = -EBADF; | |
842 | out_file = fget_light(out_fd, &fput_needed_out); | |
843 | if (!out_file) | |
844 | goto fput_in; | |
845 | if (!(out_file->f_mode & FMODE_WRITE)) | |
846 | goto fput_out; | |
847 | retval = -EINVAL; | |
848 | in_inode = in_file->f_path.dentry->d_inode; | |
849 | out_inode = out_file->f_path.dentry->d_inode; | |
850 | retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count); | |
851 | if (retval < 0) | |
852 | goto fput_out; | |
853 | count = retval; | |
854 | ||
855 | if (!max) | |
856 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); | |
857 | ||
858 | pos = *ppos; | |
859 | if (unlikely(pos + count > max)) { | |
860 | retval = -EOVERFLOW; | |
861 | if (pos >= max) | |
862 | goto fput_out; | |
863 | count = max - pos; | |
864 | } | |
865 | ||
866 | fl = 0; | |
867 | #if 0 | |
868 | /* | |
869 | * We need to debate whether we can enable this or not. The | |
870 | * man page documents EAGAIN return for the output at least, | |
871 | * and the application is arguably buggy if it doesn't expect | |
872 | * EAGAIN on a non-blocking file descriptor. | |
873 | */ | |
874 | if (in_file->f_flags & O_NONBLOCK) | |
875 | fl = SPLICE_F_NONBLOCK; | |
876 | #endif | |
877 | retval = do_splice_direct(in_file, ppos, out_file, count, fl); | |
878 | ||
879 | if (retval > 0) { | |
880 | add_rchar(current, retval); | |
881 | add_wchar(current, retval); | |
882 | } | |
883 | ||
884 | inc_syscr(current); | |
885 | inc_syscw(current); | |
886 | if (*ppos > max) | |
887 | retval = -EOVERFLOW; | |
888 | ||
889 | fput_out: | |
890 | fput_light(out_file, fput_needed_out); | |
891 | fput_in: | |
892 | fput_light(in_file, fput_needed_in); | |
893 | out: | |
894 | return retval; | |
895 | } | |
896 | ||
897 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) | |
898 | { | |
899 | loff_t pos; | |
900 | off_t off; | |
901 | ssize_t ret; | |
902 | ||
903 | if (offset) { | |
904 | if (unlikely(get_user(off, offset))) | |
905 | return -EFAULT; | |
906 | pos = off; | |
907 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); | |
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 | ||
916 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) | |
917 | { | |
918 | loff_t pos; | |
919 | ssize_t ret; | |
920 | ||
921 | if (offset) { | |
922 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) | |
923 | return -EFAULT; | |
924 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); | |
925 | if (unlikely(put_user(pos, offset))) | |
926 | return -EFAULT; | |
927 | return ret; | |
928 | } | |
929 | ||
930 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
931 | } |