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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/fsnotify.h> | |
13 | #include <linux/security.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/syscalls.h> | |
16 | #include <linux/pagemap.h> | |
17 | #include <linux/splice.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 | .splice_read = generic_file_splice_read, | |
29 | }; | |
30 | ||
31 | EXPORT_SYMBOL(generic_ro_fops); | |
32 | ||
33 | static inline int unsigned_offsets(struct file *file) | |
34 | { | |
35 | return file->f_mode & FMODE_UNSIGNED_OFFSET; | |
36 | } | |
37 | ||
38 | /** | |
39 | * generic_file_llseek_unlocked - lockless generic llseek implementation | |
40 | * @file: file structure to seek on | |
41 | * @offset: file offset to seek to | |
42 | * @origin: type of seek | |
43 | * | |
44 | * Updates the file offset to the value specified by @offset and @origin. | |
45 | * Locking must be provided by the caller. | |
46 | */ | |
47 | loff_t | |
48 | generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin) | |
49 | { | |
50 | struct inode *inode = file->f_mapping->host; | |
51 | ||
52 | switch (origin) { | |
53 | case SEEK_END: | |
54 | offset += inode->i_size; | |
55 | break; | |
56 | case SEEK_CUR: | |
57 | /* | |
58 | * Here we special-case the lseek(fd, 0, SEEK_CUR) | |
59 | * position-querying operation. Avoid rewriting the "same" | |
60 | * f_pos value back to the file because a concurrent read(), | |
61 | * write() or lseek() might have altered it | |
62 | */ | |
63 | if (offset == 0) | |
64 | return file->f_pos; | |
65 | offset += file->f_pos; | |
66 | break; | |
67 | case SEEK_DATA: | |
68 | /* | |
69 | * In the generic case the entire file is data, so as long as | |
70 | * offset isn't at the end of the file then the offset is data. | |
71 | */ | |
72 | if (offset >= inode->i_size) | |
73 | return -ENXIO; | |
74 | break; | |
75 | case SEEK_HOLE: | |
76 | /* | |
77 | * There is a virtual hole at the end of the file, so as long as | |
78 | * offset isn't i_size or larger, return i_size. | |
79 | */ | |
80 | if (offset >= inode->i_size) | |
81 | return -ENXIO; | |
82 | offset = inode->i_size; | |
83 | break; | |
84 | } | |
85 | ||
86 | if (offset < 0 && !unsigned_offsets(file)) | |
87 | return -EINVAL; | |
88 | if (offset > inode->i_sb->s_maxbytes) | |
89 | return -EINVAL; | |
90 | ||
91 | /* Special lock needed here? */ | |
92 | if (offset != file->f_pos) { | |
93 | file->f_pos = offset; | |
94 | file->f_version = 0; | |
95 | } | |
96 | ||
97 | return offset; | |
98 | } | |
99 | EXPORT_SYMBOL(generic_file_llseek_unlocked); | |
100 | ||
101 | /** | |
102 | * generic_file_llseek - generic llseek implementation for regular files | |
103 | * @file: file structure to seek on | |
104 | * @offset: file offset to seek to | |
105 | * @origin: type of seek | |
106 | * | |
107 | * This is a generic implemenation of ->llseek useable for all normal local | |
108 | * filesystems. It just updates the file offset to the value specified by | |
109 | * @offset and @origin under i_mutex. | |
110 | */ | |
111 | loff_t generic_file_llseek(struct file *file, loff_t offset, int origin) | |
112 | { | |
113 | loff_t rval; | |
114 | ||
115 | mutex_lock(&file->f_dentry->d_inode->i_mutex); | |
116 | rval = generic_file_llseek_unlocked(file, offset, origin); | |
117 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); | |
118 | ||
119 | return rval; | |
120 | } | |
121 | EXPORT_SYMBOL(generic_file_llseek); | |
122 | ||
123 | /** | |
124 | * noop_llseek - No Operation Performed llseek implementation | |
125 | * @file: file structure to seek on | |
126 | * @offset: file offset to seek to | |
127 | * @origin: type of seek | |
128 | * | |
129 | * This is an implementation of ->llseek useable for the rare special case when | |
130 | * userspace expects the seek to succeed but the (device) file is actually not | |
131 | * able to perform the seek. In this case you use noop_llseek() instead of | |
132 | * falling back to the default implementation of ->llseek. | |
133 | */ | |
134 | loff_t noop_llseek(struct file *file, loff_t offset, int origin) | |
135 | { | |
136 | return file->f_pos; | |
137 | } | |
138 | EXPORT_SYMBOL(noop_llseek); | |
139 | ||
140 | loff_t no_llseek(struct file *file, loff_t offset, int origin) | |
141 | { | |
142 | return -ESPIPE; | |
143 | } | |
144 | EXPORT_SYMBOL(no_llseek); | |
145 | ||
146 | loff_t default_llseek(struct file *file, loff_t offset, int origin) | |
147 | { | |
148 | struct inode *inode = file->f_path.dentry->d_inode; | |
149 | loff_t retval; | |
150 | ||
151 | mutex_lock(&inode->i_mutex); | |
152 | switch (origin) { | |
153 | case SEEK_END: | |
154 | offset += i_size_read(inode); | |
155 | break; | |
156 | case SEEK_CUR: | |
157 | if (offset == 0) { | |
158 | retval = file->f_pos; | |
159 | goto out; | |
160 | } | |
161 | offset += file->f_pos; | |
162 | break; | |
163 | case SEEK_DATA: | |
164 | /* | |
165 | * In the generic case the entire file is data, so as | |
166 | * long as offset isn't at the end of the file then the | |
167 | * offset is data. | |
168 | */ | |
169 | if (offset >= inode->i_size) | |
170 | return -ENXIO; | |
171 | break; | |
172 | case SEEK_HOLE: | |
173 | /* | |
174 | * There is a virtual hole at the end of the file, so | |
175 | * as long as offset isn't i_size or larger, return | |
176 | * i_size. | |
177 | */ | |
178 | if (offset >= inode->i_size) | |
179 | return -ENXIO; | |
180 | offset = inode->i_size; | |
181 | break; | |
182 | } | |
183 | retval = -EINVAL; | |
184 | if (offset >= 0 || unsigned_offsets(file)) { | |
185 | if (offset != file->f_pos) { | |
186 | file->f_pos = offset; | |
187 | file->f_version = 0; | |
188 | } | |
189 | retval = offset; | |
190 | } | |
191 | out: | |
192 | mutex_unlock(&inode->i_mutex); | |
193 | return retval; | |
194 | } | |
195 | EXPORT_SYMBOL(default_llseek); | |
196 | ||
197 | loff_t vfs_llseek(struct file *file, loff_t offset, int origin) | |
198 | { | |
199 | loff_t (*fn)(struct file *, loff_t, int); | |
200 | ||
201 | fn = no_llseek; | |
202 | if (file->f_mode & FMODE_LSEEK) { | |
203 | if (file->f_op && file->f_op->llseek) | |
204 | fn = file->f_op->llseek; | |
205 | } | |
206 | return fn(file, offset, origin); | |
207 | } | |
208 | EXPORT_SYMBOL(vfs_llseek); | |
209 | ||
210 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, origin) | |
211 | { | |
212 | off_t retval; | |
213 | struct file * file; | |
214 | int fput_needed; | |
215 | ||
216 | retval = -EBADF; | |
217 | file = fget_light(fd, &fput_needed); | |
218 | if (!file) | |
219 | goto bad; | |
220 | ||
221 | retval = -EINVAL; | |
222 | if (origin <= SEEK_MAX) { | |
223 | loff_t res = vfs_llseek(file, offset, origin); | |
224 | retval = res; | |
225 | if (res != (loff_t)retval) | |
226 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ | |
227 | } | |
228 | fput_light(file, fput_needed); | |
229 | bad: | |
230 | return retval; | |
231 | } | |
232 | ||
233 | #ifdef __ARCH_WANT_SYS_LLSEEK | |
234 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, | |
235 | unsigned long, offset_low, loff_t __user *, result, | |
236 | unsigned int, origin) | |
237 | { | |
238 | int retval; | |
239 | struct file * file; | |
240 | loff_t offset; | |
241 | int fput_needed; | |
242 | ||
243 | retval = -EBADF; | |
244 | file = fget_light(fd, &fput_needed); | |
245 | if (!file) | |
246 | goto bad; | |
247 | ||
248 | retval = -EINVAL; | |
249 | if (origin > SEEK_MAX) | |
250 | goto out_putf; | |
251 | ||
252 | offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low, | |
253 | origin); | |
254 | ||
255 | retval = (int)offset; | |
256 | if (offset >= 0) { | |
257 | retval = -EFAULT; | |
258 | if (!copy_to_user(result, &offset, sizeof(offset))) | |
259 | retval = 0; | |
260 | } | |
261 | out_putf: | |
262 | fput_light(file, fput_needed); | |
263 | bad: | |
264 | return retval; | |
265 | } | |
266 | #endif | |
267 | ||
268 | ||
269 | /* | |
270 | * rw_verify_area doesn't like huge counts. We limit | |
271 | * them to something that fits in "int" so that others | |
272 | * won't have to do range checks all the time. | |
273 | */ | |
274 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) | |
275 | { | |
276 | struct inode *inode; | |
277 | loff_t pos; | |
278 | int retval = -EINVAL; | |
279 | ||
280 | inode = file->f_path.dentry->d_inode; | |
281 | if (unlikely((ssize_t) count < 0)) | |
282 | return retval; | |
283 | pos = *ppos; | |
284 | if (unlikely(pos < 0)) { | |
285 | if (!unsigned_offsets(file)) | |
286 | return retval; | |
287 | if (count >= -pos) /* both values are in 0..LLONG_MAX */ | |
288 | return -EOVERFLOW; | |
289 | } else if (unlikely((loff_t) (pos + count) < 0)) { | |
290 | if (!unsigned_offsets(file)) | |
291 | return retval; | |
292 | } | |
293 | ||
294 | if (unlikely(inode->i_flock && mandatory_lock(inode))) { | |
295 | retval = locks_mandatory_area( | |
296 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, | |
297 | inode, file, pos, count); | |
298 | if (retval < 0) | |
299 | return retval; | |
300 | } | |
301 | retval = security_file_permission(file, | |
302 | read_write == READ ? MAY_READ : MAY_WRITE); | |
303 | if (retval) | |
304 | return retval; | |
305 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; | |
306 | } | |
307 | ||
308 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) | |
309 | { | |
310 | set_current_state(TASK_UNINTERRUPTIBLE); | |
311 | if (!kiocbIsKicked(iocb)) | |
312 | schedule(); | |
313 | else | |
314 | kiocbClearKicked(iocb); | |
315 | __set_current_state(TASK_RUNNING); | |
316 | } | |
317 | ||
318 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) | |
319 | { | |
320 | struct iovec iov = { .iov_base = buf, .iov_len = len }; | |
321 | struct kiocb kiocb; | |
322 | ssize_t ret; | |
323 | ||
324 | init_sync_kiocb(&kiocb, filp); | |
325 | kiocb.ki_pos = *ppos; | |
326 | kiocb.ki_left = len; | |
327 | kiocb.ki_nbytes = len; | |
328 | ||
329 | for (;;) { | |
330 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); | |
331 | if (ret != -EIOCBRETRY) | |
332 | break; | |
333 | wait_on_retry_sync_kiocb(&kiocb); | |
334 | } | |
335 | ||
336 | if (-EIOCBQUEUED == ret) | |
337 | ret = wait_on_sync_kiocb(&kiocb); | |
338 | *ppos = kiocb.ki_pos; | |
339 | return ret; | |
340 | } | |
341 | ||
342 | EXPORT_SYMBOL(do_sync_read); | |
343 | ||
344 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) | |
345 | { | |
346 | ssize_t ret; | |
347 | ||
348 | if (!(file->f_mode & FMODE_READ)) | |
349 | return -EBADF; | |
350 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) | |
351 | return -EINVAL; | |
352 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) | |
353 | return -EFAULT; | |
354 | ||
355 | ret = rw_verify_area(READ, file, pos, count); | |
356 | if (ret >= 0) { | |
357 | count = ret; | |
358 | if (file->f_op->read) | |
359 | ret = file->f_op->read(file, buf, count, pos); | |
360 | else | |
361 | ret = do_sync_read(file, buf, count, pos); | |
362 | if (ret > 0) { | |
363 | fsnotify_access(file); | |
364 | add_rchar(current, ret); | |
365 | } | |
366 | inc_syscr(current); | |
367 | } | |
368 | ||
369 | return ret; | |
370 | } | |
371 | ||
372 | EXPORT_SYMBOL(vfs_read); | |
373 | ||
374 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) | |
375 | { | |
376 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; | |
377 | struct kiocb kiocb; | |
378 | ssize_t ret; | |
379 | ||
380 | init_sync_kiocb(&kiocb, filp); | |
381 | kiocb.ki_pos = *ppos; | |
382 | kiocb.ki_left = len; | |
383 | kiocb.ki_nbytes = len; | |
384 | ||
385 | for (;;) { | |
386 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); | |
387 | if (ret != -EIOCBRETRY) | |
388 | break; | |
389 | wait_on_retry_sync_kiocb(&kiocb); | |
390 | } | |
391 | ||
392 | if (-EIOCBQUEUED == ret) | |
393 | ret = wait_on_sync_kiocb(&kiocb); | |
394 | *ppos = kiocb.ki_pos; | |
395 | return ret; | |
396 | } | |
397 | ||
398 | EXPORT_SYMBOL(do_sync_write); | |
399 | ||
400 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) | |
401 | { | |
402 | ssize_t ret; | |
403 | ||
404 | if (!(file->f_mode & FMODE_WRITE)) | |
405 | return -EBADF; | |
406 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) | |
407 | return -EINVAL; | |
408 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) | |
409 | return -EFAULT; | |
410 | ||
411 | ret = rw_verify_area(WRITE, file, pos, count); | |
412 | if (ret >= 0) { | |
413 | count = ret; | |
414 | if (file->f_op->write) | |
415 | ret = file->f_op->write(file, buf, count, pos); | |
416 | else | |
417 | ret = do_sync_write(file, buf, count, pos); | |
418 | if (ret > 0) { | |
419 | fsnotify_modify(file); | |
420 | add_wchar(current, ret); | |
421 | } | |
422 | inc_syscw(current); | |
423 | } | |
424 | ||
425 | return ret; | |
426 | } | |
427 | ||
428 | EXPORT_SYMBOL(vfs_write); | |
429 | ||
430 | static inline loff_t file_pos_read(struct file *file) | |
431 | { | |
432 | return file->f_pos; | |
433 | } | |
434 | ||
435 | static inline void file_pos_write(struct file *file, loff_t pos) | |
436 | { | |
437 | file->f_pos = pos; | |
438 | } | |
439 | ||
440 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) | |
441 | { | |
442 | struct file *file; | |
443 | ssize_t ret = -EBADF; | |
444 | int fput_needed; | |
445 | ||
446 | file = fget_light(fd, &fput_needed); | |
447 | if (file) { | |
448 | loff_t pos = file_pos_read(file); | |
449 | ret = vfs_read(file, buf, count, &pos); | |
450 | file_pos_write(file, pos); | |
451 | fput_light(file, fput_needed); | |
452 | } | |
453 | ||
454 | return ret; | |
455 | } | |
456 | ||
457 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, | |
458 | size_t, count) | |
459 | { | |
460 | struct file *file; | |
461 | ssize_t ret = -EBADF; | |
462 | int fput_needed; | |
463 | ||
464 | file = fget_light(fd, &fput_needed); | |
465 | if (file) { | |
466 | loff_t pos = file_pos_read(file); | |
467 | ret = vfs_write(file, buf, count, &pos); | |
468 | file_pos_write(file, pos); | |
469 | fput_light(file, fput_needed); | |
470 | } | |
471 | ||
472 | return ret; | |
473 | } | |
474 | ||
475 | SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf, | |
476 | size_t count, loff_t pos) | |
477 | { | |
478 | struct file *file; | |
479 | ssize_t ret = -EBADF; | |
480 | int fput_needed; | |
481 | ||
482 | if (pos < 0) | |
483 | return -EINVAL; | |
484 | ||
485 | file = fget_light(fd, &fput_needed); | |
486 | if (file) { | |
487 | ret = -ESPIPE; | |
488 | if (file->f_mode & FMODE_PREAD) | |
489 | ret = vfs_read(file, buf, count, &pos); | |
490 | fput_light(file, fput_needed); | |
491 | } | |
492 | ||
493 | return ret; | |
494 | } | |
495 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
496 | asmlinkage long SyS_pread64(long fd, long buf, long count, loff_t pos) | |
497 | { | |
498 | return SYSC_pread64((unsigned int) fd, (char __user *) buf, | |
499 | (size_t) count, pos); | |
500 | } | |
501 | SYSCALL_ALIAS(sys_pread64, SyS_pread64); | |
502 | #endif | |
503 | ||
504 | SYSCALL_DEFINE(pwrite64)(unsigned int fd, const char __user *buf, | |
505 | size_t count, loff_t pos) | |
506 | { | |
507 | struct file *file; | |
508 | ssize_t ret = -EBADF; | |
509 | int fput_needed; | |
510 | ||
511 | if (pos < 0) | |
512 | return -EINVAL; | |
513 | ||
514 | file = fget_light(fd, &fput_needed); | |
515 | if (file) { | |
516 | ret = -ESPIPE; | |
517 | if (file->f_mode & FMODE_PWRITE) | |
518 | ret = vfs_write(file, buf, count, &pos); | |
519 | fput_light(file, fput_needed); | |
520 | } | |
521 | ||
522 | return ret; | |
523 | } | |
524 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS | |
525 | asmlinkage long SyS_pwrite64(long fd, long buf, long count, loff_t pos) | |
526 | { | |
527 | return SYSC_pwrite64((unsigned int) fd, (const char __user *) buf, | |
528 | (size_t) count, pos); | |
529 | } | |
530 | SYSCALL_ALIAS(sys_pwrite64, SyS_pwrite64); | |
531 | #endif | |
532 | ||
533 | /* | |
534 | * Reduce an iovec's length in-place. Return the resulting number of segments | |
535 | */ | |
536 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) | |
537 | { | |
538 | unsigned long seg = 0; | |
539 | size_t len = 0; | |
540 | ||
541 | while (seg < nr_segs) { | |
542 | seg++; | |
543 | if (len + iov->iov_len >= to) { | |
544 | iov->iov_len = to - len; | |
545 | break; | |
546 | } | |
547 | len += iov->iov_len; | |
548 | iov++; | |
549 | } | |
550 | return seg; | |
551 | } | |
552 | EXPORT_SYMBOL(iov_shorten); | |
553 | ||
554 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, | |
555 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) | |
556 | { | |
557 | struct kiocb kiocb; | |
558 | ssize_t ret; | |
559 | ||
560 | init_sync_kiocb(&kiocb, filp); | |
561 | kiocb.ki_pos = *ppos; | |
562 | kiocb.ki_left = len; | |
563 | kiocb.ki_nbytes = len; | |
564 | ||
565 | for (;;) { | |
566 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); | |
567 | if (ret != -EIOCBRETRY) | |
568 | break; | |
569 | wait_on_retry_sync_kiocb(&kiocb); | |
570 | } | |
571 | ||
572 | if (ret == -EIOCBQUEUED) | |
573 | ret = wait_on_sync_kiocb(&kiocb); | |
574 | *ppos = kiocb.ki_pos; | |
575 | return ret; | |
576 | } | |
577 | ||
578 | /* Do it by hand, with file-ops */ | |
579 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, | |
580 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) | |
581 | { | |
582 | struct iovec *vector = iov; | |
583 | ssize_t ret = 0; | |
584 | ||
585 | while (nr_segs > 0) { | |
586 | void __user *base; | |
587 | size_t len; | |
588 | ssize_t nr; | |
589 | ||
590 | base = vector->iov_base; | |
591 | len = vector->iov_len; | |
592 | vector++; | |
593 | nr_segs--; | |
594 | ||
595 | nr = fn(filp, base, len, ppos); | |
596 | ||
597 | if (nr < 0) { | |
598 | if (!ret) | |
599 | ret = nr; | |
600 | break; | |
601 | } | |
602 | ret += nr; | |
603 | if (nr != len) | |
604 | break; | |
605 | } | |
606 | ||
607 | return ret; | |
608 | } | |
609 | ||
610 | /* A write operation does a read from user space and vice versa */ | |
611 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) | |
612 | ||
613 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, | |
614 | unsigned long nr_segs, unsigned long fast_segs, | |
615 | struct iovec *fast_pointer, | |
616 | struct iovec **ret_pointer) | |
617 | { | |
618 | unsigned long seg; | |
619 | ssize_t ret; | |
620 | struct iovec *iov = fast_pointer; | |
621 | ||
622 | /* | |
623 | * SuS says "The readv() function *may* fail if the iovcnt argument | |
624 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
625 | * traditionally returned zero for zero segments, so... | |
626 | */ | |
627 | if (nr_segs == 0) { | |
628 | ret = 0; | |
629 | goto out; | |
630 | } | |
631 | ||
632 | /* | |
633 | * First get the "struct iovec" from user memory and | |
634 | * verify all the pointers | |
635 | */ | |
636 | if (nr_segs > UIO_MAXIOV) { | |
637 | ret = -EINVAL; | |
638 | goto out; | |
639 | } | |
640 | if (nr_segs > fast_segs) { | |
641 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); | |
642 | if (iov == NULL) { | |
643 | ret = -ENOMEM; | |
644 | goto out; | |
645 | } | |
646 | } | |
647 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { | |
648 | ret = -EFAULT; | |
649 | goto out; | |
650 | } | |
651 | ||
652 | /* | |
653 | * According to the Single Unix Specification we should return EINVAL | |
654 | * if an element length is < 0 when cast to ssize_t or if the | |
655 | * total length would overflow the ssize_t return value of the | |
656 | * system call. | |
657 | * | |
658 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
659 | * overflow case. | |
660 | */ | |
661 | ret = 0; | |
662 | for (seg = 0; seg < nr_segs; seg++) { | |
663 | void __user *buf = iov[seg].iov_base; | |
664 | ssize_t len = (ssize_t)iov[seg].iov_len; | |
665 | ||
666 | /* see if we we're about to use an invalid len or if | |
667 | * it's about to overflow ssize_t */ | |
668 | if (len < 0) { | |
669 | ret = -EINVAL; | |
670 | goto out; | |
671 | } | |
672 | if (unlikely(!access_ok(vrfy_dir(type), buf, len))) { | |
673 | ret = -EFAULT; | |
674 | goto out; | |
675 | } | |
676 | if (len > MAX_RW_COUNT - ret) { | |
677 | len = MAX_RW_COUNT - ret; | |
678 | iov[seg].iov_len = len; | |
679 | } | |
680 | ret += len; | |
681 | } | |
682 | out: | |
683 | *ret_pointer = iov; | |
684 | return ret; | |
685 | } | |
686 | ||
687 | static ssize_t do_readv_writev(int type, struct file *file, | |
688 | const struct iovec __user * uvector, | |
689 | unsigned long nr_segs, loff_t *pos) | |
690 | { | |
691 | size_t tot_len; | |
692 | struct iovec iovstack[UIO_FASTIOV]; | |
693 | struct iovec *iov = iovstack; | |
694 | ssize_t ret; | |
695 | io_fn_t fn; | |
696 | iov_fn_t fnv; | |
697 | ||
698 | if (!file->f_op) { | |
699 | ret = -EINVAL; | |
700 | goto out; | |
701 | } | |
702 | ||
703 | ret = rw_copy_check_uvector(type, uvector, nr_segs, | |
704 | ARRAY_SIZE(iovstack), iovstack, &iov); | |
705 | if (ret <= 0) | |
706 | goto out; | |
707 | ||
708 | tot_len = ret; | |
709 | ret = rw_verify_area(type, file, pos, tot_len); | |
710 | if (ret < 0) | |
711 | goto out; | |
712 | ||
713 | fnv = NULL; | |
714 | if (type == READ) { | |
715 | fn = file->f_op->read; | |
716 | fnv = file->f_op->aio_read; | |
717 | } else { | |
718 | fn = (io_fn_t)file->f_op->write; | |
719 | fnv = file->f_op->aio_write; | |
720 | } | |
721 | ||
722 | if (fnv) | |
723 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, | |
724 | pos, fnv); | |
725 | else | |
726 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); | |
727 | ||
728 | out: | |
729 | if (iov != iovstack) | |
730 | kfree(iov); | |
731 | if ((ret + (type == READ)) > 0) { | |
732 | if (type == READ) | |
733 | fsnotify_access(file); | |
734 | else | |
735 | fsnotify_modify(file); | |
736 | } | |
737 | return ret; | |
738 | } | |
739 | ||
740 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, | |
741 | unsigned long vlen, loff_t *pos) | |
742 | { | |
743 | if (!(file->f_mode & FMODE_READ)) | |
744 | return -EBADF; | |
745 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) | |
746 | return -EINVAL; | |
747 | ||
748 | return do_readv_writev(READ, file, vec, vlen, pos); | |
749 | } | |
750 | ||
751 | EXPORT_SYMBOL(vfs_readv); | |
752 | ||
753 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, | |
754 | unsigned long vlen, loff_t *pos) | |
755 | { | |
756 | if (!(file->f_mode & FMODE_WRITE)) | |
757 | return -EBADF; | |
758 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) | |
759 | return -EINVAL; | |
760 | ||
761 | return do_readv_writev(WRITE, file, vec, vlen, pos); | |
762 | } | |
763 | ||
764 | EXPORT_SYMBOL(vfs_writev); | |
765 | ||
766 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, | |
767 | unsigned long, vlen) | |
768 | { | |
769 | struct file *file; | |
770 | ssize_t ret = -EBADF; | |
771 | int fput_needed; | |
772 | ||
773 | file = fget_light(fd, &fput_needed); | |
774 | if (file) { | |
775 | loff_t pos = file_pos_read(file); | |
776 | ret = vfs_readv(file, vec, vlen, &pos); | |
777 | file_pos_write(file, pos); | |
778 | fput_light(file, fput_needed); | |
779 | } | |
780 | ||
781 | if (ret > 0) | |
782 | add_rchar(current, ret); | |
783 | inc_syscr(current); | |
784 | return ret; | |
785 | } | |
786 | ||
787 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, | |
788 | unsigned long, vlen) | |
789 | { | |
790 | struct file *file; | |
791 | ssize_t ret = -EBADF; | |
792 | int fput_needed; | |
793 | ||
794 | file = fget_light(fd, &fput_needed); | |
795 | if (file) { | |
796 | loff_t pos = file_pos_read(file); | |
797 | ret = vfs_writev(file, vec, vlen, &pos); | |
798 | file_pos_write(file, pos); | |
799 | fput_light(file, fput_needed); | |
800 | } | |
801 | ||
802 | if (ret > 0) | |
803 | add_wchar(current, ret); | |
804 | inc_syscw(current); | |
805 | return ret; | |
806 | } | |
807 | ||
808 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) | |
809 | { | |
810 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) | |
811 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; | |
812 | } | |
813 | ||
814 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, | |
815 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) | |
816 | { | |
817 | loff_t pos = pos_from_hilo(pos_h, pos_l); | |
818 | struct file *file; | |
819 | ssize_t ret = -EBADF; | |
820 | int fput_needed; | |
821 | ||
822 | if (pos < 0) | |
823 | return -EINVAL; | |
824 | ||
825 | file = fget_light(fd, &fput_needed); | |
826 | if (file) { | |
827 | ret = -ESPIPE; | |
828 | if (file->f_mode & FMODE_PREAD) | |
829 | ret = vfs_readv(file, vec, vlen, &pos); | |
830 | fput_light(file, fput_needed); | |
831 | } | |
832 | ||
833 | if (ret > 0) | |
834 | add_rchar(current, ret); | |
835 | inc_syscr(current); | |
836 | return ret; | |
837 | } | |
838 | ||
839 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, | |
840 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) | |
841 | { | |
842 | loff_t pos = pos_from_hilo(pos_h, pos_l); | |
843 | struct file *file; | |
844 | ssize_t ret = -EBADF; | |
845 | int fput_needed; | |
846 | ||
847 | if (pos < 0) | |
848 | return -EINVAL; | |
849 | ||
850 | file = fget_light(fd, &fput_needed); | |
851 | if (file) { | |
852 | ret = -ESPIPE; | |
853 | if (file->f_mode & FMODE_PWRITE) | |
854 | ret = vfs_writev(file, vec, vlen, &pos); | |
855 | fput_light(file, fput_needed); | |
856 | } | |
857 | ||
858 | if (ret > 0) | |
859 | add_wchar(current, ret); | |
860 | inc_syscw(current); | |
861 | return ret; | |
862 | } | |
863 | ||
864 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, | |
865 | size_t count, loff_t max) | |
866 | { | |
867 | struct file * in_file, * out_file; | |
868 | struct inode * in_inode, * out_inode; | |
869 | loff_t pos; | |
870 | ssize_t retval; | |
871 | int fput_needed_in, fput_needed_out, fl; | |
872 | ||
873 | /* | |
874 | * Get input file, and verify that it is ok.. | |
875 | */ | |
876 | retval = -EBADF; | |
877 | in_file = fget_light(in_fd, &fput_needed_in); | |
878 | if (!in_file) | |
879 | goto out; | |
880 | if (!(in_file->f_mode & FMODE_READ)) | |
881 | goto fput_in; | |
882 | retval = -ESPIPE; | |
883 | if (!ppos) | |
884 | ppos = &in_file->f_pos; | |
885 | else | |
886 | if (!(in_file->f_mode & FMODE_PREAD)) | |
887 | goto fput_in; | |
888 | retval = rw_verify_area(READ, in_file, ppos, count); | |
889 | if (retval < 0) | |
890 | goto fput_in; | |
891 | count = retval; | |
892 | ||
893 | /* | |
894 | * Get output file, and verify that it is ok.. | |
895 | */ | |
896 | retval = -EBADF; | |
897 | out_file = fget_light(out_fd, &fput_needed_out); | |
898 | if (!out_file) | |
899 | goto fput_in; | |
900 | if (!(out_file->f_mode & FMODE_WRITE)) | |
901 | goto fput_out; | |
902 | retval = -EINVAL; | |
903 | in_inode = in_file->f_path.dentry->d_inode; | |
904 | out_inode = out_file->f_path.dentry->d_inode; | |
905 | retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count); | |
906 | if (retval < 0) | |
907 | goto fput_out; | |
908 | count = retval; | |
909 | ||
910 | if (!max) | |
911 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); | |
912 | ||
913 | pos = *ppos; | |
914 | if (unlikely(pos + count > max)) { | |
915 | retval = -EOVERFLOW; | |
916 | if (pos >= max) | |
917 | goto fput_out; | |
918 | count = max - pos; | |
919 | } | |
920 | ||
921 | fl = 0; | |
922 | #if 0 | |
923 | /* | |
924 | * We need to debate whether we can enable this or not. The | |
925 | * man page documents EAGAIN return for the output at least, | |
926 | * and the application is arguably buggy if it doesn't expect | |
927 | * EAGAIN on a non-blocking file descriptor. | |
928 | */ | |
929 | if (in_file->f_flags & O_NONBLOCK) | |
930 | fl = SPLICE_F_NONBLOCK; | |
931 | #endif | |
932 | retval = do_splice_direct(in_file, ppos, out_file, count, fl); | |
933 | ||
934 | if (retval > 0) { | |
935 | add_rchar(current, retval); | |
936 | add_wchar(current, retval); | |
937 | } | |
938 | ||
939 | inc_syscr(current); | |
940 | inc_syscw(current); | |
941 | if (*ppos > max) | |
942 | retval = -EOVERFLOW; | |
943 | ||
944 | fput_out: | |
945 | fput_light(out_file, fput_needed_out); | |
946 | fput_in: | |
947 | fput_light(in_file, fput_needed_in); | |
948 | out: | |
949 | return retval; | |
950 | } | |
951 | ||
952 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) | |
953 | { | |
954 | loff_t pos; | |
955 | off_t off; | |
956 | ssize_t ret; | |
957 | ||
958 | if (offset) { | |
959 | if (unlikely(get_user(off, offset))) | |
960 | return -EFAULT; | |
961 | pos = off; | |
962 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); | |
963 | if (unlikely(put_user(pos, offset))) | |
964 | return -EFAULT; | |
965 | return ret; | |
966 | } | |
967 | ||
968 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
969 | } | |
970 | ||
971 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) | |
972 | { | |
973 | loff_t pos; | |
974 | ssize_t ret; | |
975 | ||
976 | if (offset) { | |
977 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) | |
978 | return -EFAULT; | |
979 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); | |
980 | if (unlikely(put_user(pos, offset))) | |
981 | return -EFAULT; | |
982 | return ret; | |
983 | } | |
984 | ||
985 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
986 | } |