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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 | static int | |
35 | __negative_fpos_check(struct file *file, loff_t pos, size_t count) | |
36 | { | |
37 | /* | |
38 | * pos or pos+count is negative here, check overflow. | |
39 | * too big "count" will be caught in rw_verify_area(). | |
40 | */ | |
41 | if ((pos < 0) && (pos + count < pos)) | |
42 | return -EOVERFLOW; | |
43 | if (file->f_mode & FMODE_UNSIGNED_OFFSET) | |
44 | return 0; | |
45 | return -EINVAL; | |
46 | } | |
47 | ||
48 | /** | |
49 | * generic_file_llseek_unlocked - lockless generic llseek implementation | |
50 | * @file: file structure to seek on | |
51 | * @offset: file offset to seek to | |
52 | * @origin: type of seek | |
53 | * | |
54 | * Updates the file offset to the value specified by @offset and @origin. | |
55 | * Locking must be provided by the caller. | |
56 | */ | |
57 | loff_t | |
58 | generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin) | |
59 | { | |
60 | struct inode *inode = file->f_mapping->host; | |
61 | ||
62 | switch (origin) { | |
63 | case SEEK_END: | |
64 | offset += inode->i_size; | |
65 | break; | |
66 | case SEEK_CUR: | |
67 | /* | |
68 | * Here we special-case the lseek(fd, 0, SEEK_CUR) | |
69 | * position-querying operation. Avoid rewriting the "same" | |
70 | * f_pos value back to the file because a concurrent read(), | |
71 | * write() or lseek() might have altered it | |
72 | */ | |
73 | if (offset == 0) | |
74 | return file->f_pos; | |
75 | offset += file->f_pos; | |
76 | break; | |
77 | } | |
78 | ||
79 | if (offset < 0 && __negative_fpos_check(file, offset, 0)) | |
80 | return -EINVAL; | |
81 | if (offset > inode->i_sb->s_maxbytes) | |
82 | return -EINVAL; | |
83 | ||
84 | /* Special lock needed here? */ | |
85 | if (offset != file->f_pos) { | |
86 | file->f_pos = offset; | |
87 | file->f_version = 0; | |
88 | } | |
89 | ||
90 | return offset; | |
91 | } | |
92 | EXPORT_SYMBOL(generic_file_llseek_unlocked); | |
93 | ||
94 | /** | |
95 | * generic_file_llseek - generic llseek implementation for regular files | |
96 | * @file: file structure to seek on | |
97 | * @offset: file offset to seek to | |
98 | * @origin: type of seek | |
99 | * | |
100 | * This is a generic implemenation of ->llseek useable for all normal local | |
101 | * filesystems. It just updates the file offset to the value specified by | |
102 | * @offset and @origin under i_mutex. | |
103 | */ | |
104 | loff_t generic_file_llseek(struct file *file, loff_t offset, int origin) | |
105 | { | |
106 | loff_t rval; | |
107 | ||
108 | mutex_lock(&file->f_dentry->d_inode->i_mutex); | |
109 | rval = generic_file_llseek_unlocked(file, offset, origin); | |
110 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); | |
111 | ||
112 | return rval; | |
113 | } | |
114 | EXPORT_SYMBOL(generic_file_llseek); | |
115 | ||
116 | /** | |
117 | * noop_llseek - No Operation Performed llseek implementation | |
118 | * @file: file structure to seek on | |
119 | * @offset: file offset to seek to | |
120 | * @origin: type of seek | |
121 | * | |
122 | * This is an implementation of ->llseek useable for the rare special case when | |
123 | * userspace expects the seek to succeed but the (device) file is actually not | |
124 | * able to perform the seek. In this case you use noop_llseek() instead of | |
125 | * falling back to the default implementation of ->llseek. | |
126 | */ | |
127 | loff_t noop_llseek(struct file *file, loff_t offset, int origin) | |
128 | { | |
129 | return file->f_pos; | |
130 | } | |
131 | EXPORT_SYMBOL(noop_llseek); | |
132 | ||
133 | loff_t no_llseek(struct file *file, loff_t offset, int origin) | |
134 | { | |
135 | return -ESPIPE; | |
136 | } | |
137 | EXPORT_SYMBOL(no_llseek); | |
138 | ||
139 | loff_t default_llseek(struct file *file, loff_t offset, int origin) | |
140 | { | |
141 | loff_t retval; | |
142 | ||
143 | mutex_lock(&file->f_dentry->d_inode->i_mutex); | |
144 | switch (origin) { | |
145 | case SEEK_END: | |
146 | offset += i_size_read(file->f_path.dentry->d_inode); | |
147 | break; | |
148 | case SEEK_CUR: | |
149 | if (offset == 0) { | |
150 | retval = file->f_pos; | |
151 | goto out; | |
152 | } | |
153 | offset += file->f_pos; | |
154 | } | |
155 | retval = -EINVAL; | |
156 | if (offset >= 0 || !__negative_fpos_check(file, offset, 0)) { | |
157 | if (offset != file->f_pos) { | |
158 | file->f_pos = offset; | |
159 | file->f_version = 0; | |
160 | } | |
161 | retval = offset; | |
162 | } | |
163 | out: | |
164 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); | |
165 | return retval; | |
166 | } | |
167 | EXPORT_SYMBOL(default_llseek); | |
168 | ||
169 | loff_t vfs_llseek(struct file *file, loff_t offset, int origin) | |
170 | { | |
171 | loff_t (*fn)(struct file *, loff_t, int); | |
172 | ||
173 | fn = no_llseek; | |
174 | if (file->f_mode & FMODE_LSEEK) { | |
175 | if (file->f_op && file->f_op->llseek) | |
176 | fn = file->f_op->llseek; | |
177 | } | |
178 | return fn(file, offset, origin); | |
179 | } | |
180 | EXPORT_SYMBOL(vfs_llseek); | |
181 | ||
182 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, origin) | |
183 | { | |
184 | off_t retval; | |
185 | struct file * file; | |
186 | int fput_needed; | |
187 | ||
188 | retval = -EBADF; | |
189 | file = fget_light(fd, &fput_needed); | |
190 | if (!file) | |
191 | goto bad; | |
192 | ||
193 | retval = -EINVAL; | |
194 | if (origin <= SEEK_MAX) { | |
195 | loff_t res = vfs_llseek(file, offset, origin); | |
196 | retval = res; | |
197 | if (res != (loff_t)retval) | |
198 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ | |
199 | } | |
200 | fput_light(file, fput_needed); | |
201 | bad: | |
202 | return retval; | |
203 | } | |
204 | ||
205 | #ifdef __ARCH_WANT_SYS_LLSEEK | |
206 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, | |
207 | unsigned long, offset_low, loff_t __user *, result, | |
208 | unsigned int, origin) | |
209 | { | |
210 | int retval; | |
211 | struct file * file; | |
212 | loff_t offset; | |
213 | int fput_needed; | |
214 | ||
215 | retval = -EBADF; | |
216 | file = fget_light(fd, &fput_needed); | |
217 | if (!file) | |
218 | goto bad; | |
219 | ||
220 | retval = -EINVAL; | |
221 | if (origin > SEEK_MAX) | |
222 | goto out_putf; | |
223 | ||
224 | offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low, | |
225 | origin); | |
226 | ||
227 | retval = (int)offset; | |
228 | if (offset >= 0) { | |
229 | retval = -EFAULT; | |
230 | if (!copy_to_user(result, &offset, sizeof(offset))) | |
231 | retval = 0; | |
232 | } | |
233 | out_putf: | |
234 | fput_light(file, fput_needed); | |
235 | bad: | |
236 | return retval; | |
237 | } | |
238 | #endif | |
239 | ||
240 | ||
241 | /* | |
242 | * rw_verify_area doesn't like huge counts. We limit | |
243 | * them to something that fits in "int" so that others | |
244 | * won't have to do range checks all the time. | |
245 | */ | |
246 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) | |
247 | { | |
248 | struct inode *inode; | |
249 | loff_t pos; | |
250 | int retval = -EINVAL; | |
251 | ||
252 | inode = file->f_path.dentry->d_inode; | |
253 | if (unlikely((ssize_t) count < 0)) | |
254 | return retval; | |
255 | pos = *ppos; | |
256 | if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) { | |
257 | retval = __negative_fpos_check(file, pos, count); | |
258 | if (retval) | |
259 | return retval; | |
260 | } | |
261 | ||
262 | if (unlikely(inode->i_flock && mandatory_lock(inode))) { | |
263 | retval = locks_mandatory_area( | |
264 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, | |
265 | inode, file, pos, count); | |
266 | if (retval < 0) | |
267 | return retval; | |
268 | } | |
269 | retval = security_file_permission(file, | |
270 | read_write == READ ? MAY_READ : MAY_WRITE); | |
271 | if (retval) | |
272 | return retval; | |
273 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; | |
274 | } | |
275 | ||
276 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) | |
277 | { | |
278 | set_current_state(TASK_UNINTERRUPTIBLE); | |
279 | if (!kiocbIsKicked(iocb)) | |
280 | schedule(); | |
281 | else | |
282 | kiocbClearKicked(iocb); | |
283 | __set_current_state(TASK_RUNNING); | |
284 | } | |
285 | ||
286 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) | |
287 | { | |
288 | struct iovec iov = { .iov_base = buf, .iov_len = len }; | |
289 | struct kiocb kiocb; | |
290 | ssize_t ret; | |
291 | ||
292 | init_sync_kiocb(&kiocb, filp); | |
293 | kiocb.ki_pos = *ppos; | |
294 | kiocb.ki_left = len; | |
295 | kiocb.ki_nbytes = len; | |
296 | ||
297 | for (;;) { | |
298 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); | |
299 | if (ret != -EIOCBRETRY) | |
300 | break; | |
301 | wait_on_retry_sync_kiocb(&kiocb); | |
302 | } | |
303 | ||
304 | if (-EIOCBQUEUED == ret) | |
305 | ret = wait_on_sync_kiocb(&kiocb); | |
306 | *ppos = kiocb.ki_pos; | |
307 | return ret; | |
308 | } | |
309 | ||
310 | EXPORT_SYMBOL(do_sync_read); | |
311 | ||
312 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) | |
313 | { | |
314 | ssize_t ret; | |
315 | ||
316 | if (!(file->f_mode & FMODE_READ)) | |
317 | return -EBADF; | |
318 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) | |
319 | return -EINVAL; | |
320 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) | |
321 | return -EFAULT; | |
322 | ||
323 | ret = rw_verify_area(READ, file, pos, count); | |
324 | if (ret >= 0) { | |
325 | count = ret; | |
326 | if (file->f_op->read) | |
327 | ret = file->f_op->read(file, buf, count, pos); | |
328 | else | |
329 | ret = do_sync_read(file, buf, count, pos); | |
330 | if (ret > 0) { | |
331 | fsnotify_access(file); | |
332 | add_rchar(current, ret); | |
333 | } | |
334 | inc_syscr(current); | |
335 | } | |
336 | ||
337 | return ret; | |
338 | } | |
339 | ||
340 | EXPORT_SYMBOL(vfs_read); | |
341 | ||
342 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) | |
343 | { | |
344 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; | |
345 | struct kiocb kiocb; | |
346 | ssize_t ret; | |
347 | ||
348 | init_sync_kiocb(&kiocb, filp); | |
349 | kiocb.ki_pos = *ppos; | |
350 | kiocb.ki_left = len; | |
351 | kiocb.ki_nbytes = len; | |
352 | ||
353 | for (;;) { | |
354 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); | |
355 | if (ret != -EIOCBRETRY) | |
356 | break; | |
357 | wait_on_retry_sync_kiocb(&kiocb); | |
358 | } | |
359 | ||
360 | if (-EIOCBQUEUED == ret) | |
361 | ret = wait_on_sync_kiocb(&kiocb); | |
362 | *ppos = kiocb.ki_pos; | |
363 | return ret; | |
364 | } | |
365 | ||
366 | EXPORT_SYMBOL(do_sync_write); | |
367 | ||
368 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) | |
369 | { | |
370 | ssize_t ret; | |
371 | ||
372 | if (!(file->f_mode & FMODE_WRITE)) | |
373 | return -EBADF; | |
374 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) | |
375 | return -EINVAL; | |
376 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) | |
377 | return -EFAULT; | |
378 | ||
379 | ret = rw_verify_area(WRITE, file, pos, count); | |
380 | if (ret >= 0) { | |
381 | count = ret; | |
382 | if (file->f_op->write) | |
383 | ret = file->f_op->write(file, buf, count, pos); | |
384 | else | |
385 | ret = do_sync_write(file, buf, count, pos); | |
386 | if (ret > 0) { | |
387 | fsnotify_modify(file); | |
388 | add_wchar(current, ret); | |
389 | } | |
390 | inc_syscw(current); | |
391 | } | |
392 | ||
393 | return ret; | |
394 | } | |
395 | ||
396 | EXPORT_SYMBOL(vfs_write); | |
397 | ||
398 | static inline loff_t file_pos_read(struct file *file) | |
399 | { | |
400 | return file->f_pos; | |
401 | } | |
402 | ||
403 | static inline void file_pos_write(struct file *file, loff_t pos) | |
404 | { | |
405 | file->f_pos = pos; | |
406 | } | |
407 | ||
408 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) | |
409 | { | |
410 | struct file *file; | |
411 | ssize_t ret = -EBADF; | |
412 | int fput_needed; | |
413 | ||
414 | file = fget_light(fd, &fput_needed); | |
415 | if (file) { | |
416 | loff_t pos = file_pos_read(file); | |
417 | ret = vfs_read(file, buf, count, &pos); | |
418 | file_pos_write(file, pos); | |
419 | fput_light(file, fput_needed); | |
420 | } | |
421 | ||
422 | return ret; | |
423 | } | |
424 | ||
425 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, | |
426 | size_t, count) | |
427 | { | |
428 | struct file *file; | |
429 | ssize_t ret = -EBADF; | |
430 | int fput_needed; | |
431 | ||
432 | file = fget_light(fd, &fput_needed); | |
433 | if (file) { | |
434 | loff_t pos = file_pos_read(file); | |
435 | ret = vfs_write(file, buf, count, &pos); | |
436 | file_pos_write(file, pos); | |
437 | fput_light(file, fput_needed); | |
438 | } | |
439 | ||
440 | return ret; | |
441 | } | |
442 | ||
443 | SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf, | |
444 | size_t count, loff_t pos) | |
445 | { | |
446 | struct file *file; | |
447 | ssize_t ret = -EBADF; | |
448 | int fput_needed; | |
449 | ||
450 | if (pos < 0) | |
451 | return -EINVAL; | |
452 | ||
453 | file = fget_light(fd, &fput_needed); | |
454 | if (file) { | |
455 | ret = -ESPIPE; | |
456 | if (file->f_mode & FMODE_PREAD) | |
457 | ret = vfs_read(file, buf, count, &pos); | |
458 | fput_light(file, fput_needed); | |
459 | } | |
460 | ||
461 | return ret; | |
462 | } | |
463 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
464 | asmlinkage long SyS_pread64(long fd, long buf, long count, loff_t pos) | |
465 | { | |
466 | return SYSC_pread64((unsigned int) fd, (char __user *) buf, | |
467 | (size_t) count, pos); | |
468 | } | |
469 | SYSCALL_ALIAS(sys_pread64, SyS_pread64); | |
470 | #endif | |
471 | ||
472 | SYSCALL_DEFINE(pwrite64)(unsigned int fd, const char __user *buf, | |
473 | size_t count, loff_t pos) | |
474 | { | |
475 | struct file *file; | |
476 | ssize_t ret = -EBADF; | |
477 | int fput_needed; | |
478 | ||
479 | if (pos < 0) | |
480 | return -EINVAL; | |
481 | ||
482 | file = fget_light(fd, &fput_needed); | |
483 | if (file) { | |
484 | ret = -ESPIPE; | |
485 | if (file->f_mode & FMODE_PWRITE) | |
486 | ret = vfs_write(file, buf, count, &pos); | |
487 | fput_light(file, fput_needed); | |
488 | } | |
489 | ||
490 | return ret; | |
491 | } | |
492 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
493 | asmlinkage long SyS_pwrite64(long fd, long buf, long count, loff_t pos) | |
494 | { | |
495 | return SYSC_pwrite64((unsigned int) fd, (const char __user *) buf, | |
496 | (size_t) count, pos); | |
497 | } | |
498 | SYSCALL_ALIAS(sys_pwrite64, SyS_pwrite64); | |
499 | #endif | |
500 | ||
501 | /* | |
502 | * Reduce an iovec's length in-place. Return the resulting number of segments | |
503 | */ | |
504 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) | |
505 | { | |
506 | unsigned long seg = 0; | |
507 | size_t len = 0; | |
508 | ||
509 | while (seg < nr_segs) { | |
510 | seg++; | |
511 | if (len + iov->iov_len >= to) { | |
512 | iov->iov_len = to - len; | |
513 | break; | |
514 | } | |
515 | len += iov->iov_len; | |
516 | iov++; | |
517 | } | |
518 | return seg; | |
519 | } | |
520 | EXPORT_SYMBOL(iov_shorten); | |
521 | ||
522 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, | |
523 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) | |
524 | { | |
525 | struct kiocb kiocb; | |
526 | ssize_t ret; | |
527 | ||
528 | init_sync_kiocb(&kiocb, filp); | |
529 | kiocb.ki_pos = *ppos; | |
530 | kiocb.ki_left = len; | |
531 | kiocb.ki_nbytes = len; | |
532 | ||
533 | for (;;) { | |
534 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); | |
535 | if (ret != -EIOCBRETRY) | |
536 | break; | |
537 | wait_on_retry_sync_kiocb(&kiocb); | |
538 | } | |
539 | ||
540 | if (ret == -EIOCBQUEUED) | |
541 | ret = wait_on_sync_kiocb(&kiocb); | |
542 | *ppos = kiocb.ki_pos; | |
543 | return ret; | |
544 | } | |
545 | ||
546 | /* Do it by hand, with file-ops */ | |
547 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, | |
548 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) | |
549 | { | |
550 | struct iovec *vector = iov; | |
551 | ssize_t ret = 0; | |
552 | ||
553 | while (nr_segs > 0) { | |
554 | void __user *base; | |
555 | size_t len; | |
556 | ssize_t nr; | |
557 | ||
558 | base = vector->iov_base; | |
559 | len = vector->iov_len; | |
560 | vector++; | |
561 | nr_segs--; | |
562 | ||
563 | nr = fn(filp, base, len, ppos); | |
564 | ||
565 | if (nr < 0) { | |
566 | if (!ret) | |
567 | ret = nr; | |
568 | break; | |
569 | } | |
570 | ret += nr; | |
571 | if (nr != len) | |
572 | break; | |
573 | } | |
574 | ||
575 | return ret; | |
576 | } | |
577 | ||
578 | /* A write operation does a read from user space and vice versa */ | |
579 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) | |
580 | ||
581 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, | |
582 | unsigned long nr_segs, unsigned long fast_segs, | |
583 | struct iovec *fast_pointer, | |
584 | struct iovec **ret_pointer) | |
585 | { | |
586 | unsigned long seg; | |
587 | ssize_t ret; | |
588 | struct iovec *iov = fast_pointer; | |
589 | ||
590 | /* | |
591 | * SuS says "The readv() function *may* fail if the iovcnt argument | |
592 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
593 | * traditionally returned zero for zero segments, so... | |
594 | */ | |
595 | if (nr_segs == 0) { | |
596 | ret = 0; | |
597 | goto out; | |
598 | } | |
599 | ||
600 | /* | |
601 | * First get the "struct iovec" from user memory and | |
602 | * verify all the pointers | |
603 | */ | |
604 | if (nr_segs > UIO_MAXIOV) { | |
605 | ret = -EINVAL; | |
606 | goto out; | |
607 | } | |
608 | if (nr_segs > fast_segs) { | |
609 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); | |
610 | if (iov == NULL) { | |
611 | ret = -ENOMEM; | |
612 | goto out; | |
613 | } | |
614 | } | |
615 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { | |
616 | ret = -EFAULT; | |
617 | goto out; | |
618 | } | |
619 | ||
620 | /* | |
621 | * According to the Single Unix Specification we should return EINVAL | |
622 | * if an element length is < 0 when cast to ssize_t or if the | |
623 | * total length would overflow the ssize_t return value of the | |
624 | * system call. | |
625 | * | |
626 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
627 | * overflow case. | |
628 | */ | |
629 | ret = 0; | |
630 | for (seg = 0; seg < nr_segs; seg++) { | |
631 | void __user *buf = iov[seg].iov_base; | |
632 | ssize_t len = (ssize_t)iov[seg].iov_len; | |
633 | ||
634 | /* see if we we're about to use an invalid len or if | |
635 | * it's about to overflow ssize_t */ | |
636 | if (len < 0) { | |
637 | ret = -EINVAL; | |
638 | goto out; | |
639 | } | |
640 | if (unlikely(!access_ok(vrfy_dir(type), buf, len))) { | |
641 | ret = -EFAULT; | |
642 | goto out; | |
643 | } | |
644 | if (len > MAX_RW_COUNT - ret) { | |
645 | len = MAX_RW_COUNT - ret; | |
646 | iov[seg].iov_len = len; | |
647 | } | |
648 | ret += len; | |
649 | } | |
650 | out: | |
651 | *ret_pointer = iov; | |
652 | return ret; | |
653 | } | |
654 | ||
655 | static ssize_t do_readv_writev(int type, struct file *file, | |
656 | const struct iovec __user * uvector, | |
657 | unsigned long nr_segs, loff_t *pos) | |
658 | { | |
659 | size_t tot_len; | |
660 | struct iovec iovstack[UIO_FASTIOV]; | |
661 | struct iovec *iov = iovstack; | |
662 | ssize_t ret; | |
663 | io_fn_t fn; | |
664 | iov_fn_t fnv; | |
665 | ||
666 | if (!file->f_op) { | |
667 | ret = -EINVAL; | |
668 | goto out; | |
669 | } | |
670 | ||
671 | ret = rw_copy_check_uvector(type, uvector, nr_segs, | |
672 | ARRAY_SIZE(iovstack), iovstack, &iov); | |
673 | if (ret <= 0) | |
674 | goto out; | |
675 | ||
676 | tot_len = ret; | |
677 | ret = rw_verify_area(type, file, pos, tot_len); | |
678 | if (ret < 0) | |
679 | goto out; | |
680 | ||
681 | fnv = NULL; | |
682 | if (type == READ) { | |
683 | fn = file->f_op->read; | |
684 | fnv = file->f_op->aio_read; | |
685 | } else { | |
686 | fn = (io_fn_t)file->f_op->write; | |
687 | fnv = file->f_op->aio_write; | |
688 | } | |
689 | ||
690 | if (fnv) | |
691 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, | |
692 | pos, fnv); | |
693 | else | |
694 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); | |
695 | ||
696 | out: | |
697 | if (iov != iovstack) | |
698 | kfree(iov); | |
699 | if ((ret + (type == READ)) > 0) { | |
700 | if (type == READ) | |
701 | fsnotify_access(file); | |
702 | else | |
703 | fsnotify_modify(file); | |
704 | } | |
705 | return ret; | |
706 | } | |
707 | ||
708 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, | |
709 | unsigned long vlen, loff_t *pos) | |
710 | { | |
711 | if (!(file->f_mode & FMODE_READ)) | |
712 | return -EBADF; | |
713 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) | |
714 | return -EINVAL; | |
715 | ||
716 | return do_readv_writev(READ, file, vec, vlen, pos); | |
717 | } | |
718 | ||
719 | EXPORT_SYMBOL(vfs_readv); | |
720 | ||
721 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, | |
722 | unsigned long vlen, loff_t *pos) | |
723 | { | |
724 | if (!(file->f_mode & FMODE_WRITE)) | |
725 | return -EBADF; | |
726 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) | |
727 | return -EINVAL; | |
728 | ||
729 | return do_readv_writev(WRITE, file, vec, vlen, pos); | |
730 | } | |
731 | ||
732 | EXPORT_SYMBOL(vfs_writev); | |
733 | ||
734 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, | |
735 | unsigned long, vlen) | |
736 | { | |
737 | struct file *file; | |
738 | ssize_t ret = -EBADF; | |
739 | int fput_needed; | |
740 | ||
741 | file = fget_light(fd, &fput_needed); | |
742 | if (file) { | |
743 | loff_t pos = file_pos_read(file); | |
744 | ret = vfs_readv(file, vec, vlen, &pos); | |
745 | file_pos_write(file, pos); | |
746 | fput_light(file, fput_needed); | |
747 | } | |
748 | ||
749 | if (ret > 0) | |
750 | add_rchar(current, ret); | |
751 | inc_syscr(current); | |
752 | return ret; | |
753 | } | |
754 | ||
755 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, | |
756 | unsigned long, vlen) | |
757 | { | |
758 | struct file *file; | |
759 | ssize_t ret = -EBADF; | |
760 | int fput_needed; | |
761 | ||
762 | file = fget_light(fd, &fput_needed); | |
763 | if (file) { | |
764 | loff_t pos = file_pos_read(file); | |
765 | ret = vfs_writev(file, vec, vlen, &pos); | |
766 | file_pos_write(file, pos); | |
767 | fput_light(file, fput_needed); | |
768 | } | |
769 | ||
770 | if (ret > 0) | |
771 | add_wchar(current, ret); | |
772 | inc_syscw(current); | |
773 | return ret; | |
774 | } | |
775 | ||
776 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) | |
777 | { | |
778 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) | |
779 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; | |
780 | } | |
781 | ||
782 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, | |
783 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) | |
784 | { | |
785 | loff_t pos = pos_from_hilo(pos_h, pos_l); | |
786 | struct file *file; | |
787 | ssize_t ret = -EBADF; | |
788 | int fput_needed; | |
789 | ||
790 | if (pos < 0) | |
791 | return -EINVAL; | |
792 | ||
793 | file = fget_light(fd, &fput_needed); | |
794 | if (file) { | |
795 | ret = -ESPIPE; | |
796 | if (file->f_mode & FMODE_PREAD) | |
797 | ret = vfs_readv(file, vec, vlen, &pos); | |
798 | fput_light(file, fput_needed); | |
799 | } | |
800 | ||
801 | if (ret > 0) | |
802 | add_rchar(current, ret); | |
803 | inc_syscr(current); | |
804 | return ret; | |
805 | } | |
806 | ||
807 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, | |
808 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) | |
809 | { | |
810 | loff_t pos = pos_from_hilo(pos_h, pos_l); | |
811 | struct file *file; | |
812 | ssize_t ret = -EBADF; | |
813 | int fput_needed; | |
814 | ||
815 | if (pos < 0) | |
816 | return -EINVAL; | |
817 | ||
818 | file = fget_light(fd, &fput_needed); | |
819 | if (file) { | |
820 | ret = -ESPIPE; | |
821 | if (file->f_mode & FMODE_PWRITE) | |
822 | ret = vfs_writev(file, vec, vlen, &pos); | |
823 | fput_light(file, fput_needed); | |
824 | } | |
825 | ||
826 | if (ret > 0) | |
827 | add_wchar(current, ret); | |
828 | inc_syscw(current); | |
829 | return ret; | |
830 | } | |
831 | ||
832 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, | |
833 | size_t count, loff_t max) | |
834 | { | |
835 | struct file * in_file, * out_file; | |
836 | struct inode * in_inode, * out_inode; | |
837 | loff_t pos; | |
838 | ssize_t retval; | |
839 | int fput_needed_in, fput_needed_out, fl; | |
840 | ||
841 | /* | |
842 | * Get input file, and verify that it is ok.. | |
843 | */ | |
844 | retval = -EBADF; | |
845 | in_file = fget_light(in_fd, &fput_needed_in); | |
846 | if (!in_file) | |
847 | goto out; | |
848 | if (!(in_file->f_mode & FMODE_READ)) | |
849 | goto fput_in; | |
850 | retval = -ESPIPE; | |
851 | if (!ppos) | |
852 | ppos = &in_file->f_pos; | |
853 | else | |
854 | if (!(in_file->f_mode & FMODE_PREAD)) | |
855 | goto fput_in; | |
856 | retval = rw_verify_area(READ, in_file, ppos, count); | |
857 | if (retval < 0) | |
858 | goto fput_in; | |
859 | count = retval; | |
860 | ||
861 | /* | |
862 | * Get output file, and verify that it is ok.. | |
863 | */ | |
864 | retval = -EBADF; | |
865 | out_file = fget_light(out_fd, &fput_needed_out); | |
866 | if (!out_file) | |
867 | goto fput_in; | |
868 | if (!(out_file->f_mode & FMODE_WRITE)) | |
869 | goto fput_out; | |
870 | retval = -EINVAL; | |
871 | in_inode = in_file->f_path.dentry->d_inode; | |
872 | out_inode = out_file->f_path.dentry->d_inode; | |
873 | retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count); | |
874 | if (retval < 0) | |
875 | goto fput_out; | |
876 | count = retval; | |
877 | ||
878 | if (!max) | |
879 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); | |
880 | ||
881 | pos = *ppos; | |
882 | if (unlikely(pos + count > max)) { | |
883 | retval = -EOVERFLOW; | |
884 | if (pos >= max) | |
885 | goto fput_out; | |
886 | count = max - pos; | |
887 | } | |
888 | ||
889 | fl = 0; | |
890 | #if 0 | |
891 | /* | |
892 | * We need to debate whether we can enable this or not. The | |
893 | * man page documents EAGAIN return for the output at least, | |
894 | * and the application is arguably buggy if it doesn't expect | |
895 | * EAGAIN on a non-blocking file descriptor. | |
896 | */ | |
897 | if (in_file->f_flags & O_NONBLOCK) | |
898 | fl = SPLICE_F_NONBLOCK; | |
899 | #endif | |
900 | retval = do_splice_direct(in_file, ppos, out_file, count, fl); | |
901 | ||
902 | if (retval > 0) { | |
903 | add_rchar(current, retval); | |
904 | add_wchar(current, retval); | |
905 | } | |
906 | ||
907 | inc_syscr(current); | |
908 | inc_syscw(current); | |
909 | if (*ppos > max) | |
910 | retval = -EOVERFLOW; | |
911 | ||
912 | fput_out: | |
913 | fput_light(out_file, fput_needed_out); | |
914 | fput_in: | |
915 | fput_light(in_file, fput_needed_in); | |
916 | out: | |
917 | return retval; | |
918 | } | |
919 | ||
920 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) | |
921 | { | |
922 | loff_t pos; | |
923 | off_t off; | |
924 | ssize_t ret; | |
925 | ||
926 | if (offset) { | |
927 | if (unlikely(get_user(off, offset))) | |
928 | return -EFAULT; | |
929 | pos = off; | |
930 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); | |
931 | if (unlikely(put_user(pos, offset))) | |
932 | return -EFAULT; | |
933 | return ret; | |
934 | } | |
935 | ||
936 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
937 | } | |
938 | ||
939 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) | |
940 | { | |
941 | loff_t pos; | |
942 | ssize_t ret; | |
943 | ||
944 | if (offset) { | |
945 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) | |
946 | return -EFAULT; | |
947 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); | |
948 | if (unlikely(put_user(pos, offset))) | |
949 | return -EFAULT; | |
950 | return ret; | |
951 | } | |
952 | ||
953 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
954 | } |