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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/export.h> |
15 | #include <linux/syscalls.h> |
16 | #include <linux/pagemap.h> |
17 | #include <linux/splice.h> |
18 | #include <linux/compat.h> |
19 | #include "read_write.h" |
20 | #include "internal.h" |
21 | |
22 | #include <asm/uaccess.h> |
23 | #include <asm/unistd.h> |
24 | |
25 | const struct file_operations generic_ro_fops = { |
26 | .llseek = generic_file_llseek, |
27 | .read = do_sync_read, |
28 | .aio_read = generic_file_aio_read, |
29 | .mmap = generic_file_readonly_mmap, |
30 | .splice_read = generic_file_splice_read, |
31 | }; |
32 | |
33 | EXPORT_SYMBOL(generic_ro_fops); |
34 | |
35 | static inline int unsigned_offsets(struct file *file) |
36 | { |
37 | return file->f_mode & FMODE_UNSIGNED_OFFSET; |
38 | } |
39 | |
40 | static loff_t lseek_execute(struct file *file, struct inode *inode, |
41 | loff_t offset, loff_t maxsize) |
42 | { |
43 | if (offset < 0 && !unsigned_offsets(file)) |
44 | return -EINVAL; |
45 | if (offset > maxsize) |
46 | return -EINVAL; |
47 | |
48 | if (offset != file->f_pos) { |
49 | file->f_pos = offset; |
50 | file->f_version = 0; |
51 | } |
52 | return offset; |
53 | } |
54 | |
55 | /** |
56 | * generic_file_llseek_size - generic llseek implementation for regular files |
57 | * @file: file structure to seek on |
58 | * @offset: file offset to seek to |
59 | * @whence: type of seek |
60 | * @size: max size of this file in file system |
61 | * @eof: offset used for SEEK_END position |
62 | * |
63 | * This is a variant of generic_file_llseek that allows passing in a custom |
64 | * maximum file size and a custom EOF position, for e.g. hashed directories |
65 | * |
66 | * Synchronization: |
67 | * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms) |
68 | * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes. |
69 | * read/writes behave like SEEK_SET against seeks. |
70 | */ |
71 | loff_t |
72 | generic_file_llseek_size(struct file *file, loff_t offset, int whence, |
73 | loff_t maxsize, loff_t eof) |
74 | { |
75 | struct inode *inode = file->f_mapping->host; |
76 | |
77 | switch (whence) { |
78 | case SEEK_END: |
79 | offset += eof; |
80 | break; |
81 | case SEEK_CUR: |
82 | /* |
83 | * Here we special-case the lseek(fd, 0, SEEK_CUR) |
84 | * position-querying operation. Avoid rewriting the "same" |
85 | * f_pos value back to the file because a concurrent read(), |
86 | * write() or lseek() might have altered it |
87 | */ |
88 | if (offset == 0) |
89 | return file->f_pos; |
90 | /* |
91 | * f_lock protects against read/modify/write race with other |
92 | * SEEK_CURs. Note that parallel writes and reads behave |
93 | * like SEEK_SET. |
94 | */ |
95 | spin_lock(&file->f_lock); |
96 | offset = lseek_execute(file, inode, file->f_pos + offset, |
97 | maxsize); |
98 | spin_unlock(&file->f_lock); |
99 | return offset; |
100 | case SEEK_DATA: |
101 | /* |
102 | * In the generic case the entire file is data, so as long as |
103 | * offset isn't at the end of the file then the offset is data. |
104 | */ |
105 | if (offset >= eof) |
106 | return -ENXIO; |
107 | break; |
108 | case SEEK_HOLE: |
109 | /* |
110 | * There is a virtual hole at the end of the file, so as long as |
111 | * offset isn't i_size or larger, return i_size. |
112 | */ |
113 | if (offset >= eof) |
114 | return -ENXIO; |
115 | offset = eof; |
116 | break; |
117 | } |
118 | |
119 | return lseek_execute(file, inode, offset, maxsize); |
120 | } |
121 | EXPORT_SYMBOL(generic_file_llseek_size); |
122 | |
123 | /** |
124 | * generic_file_llseek - generic llseek implementation for regular files |
125 | * @file: file structure to seek on |
126 | * @offset: file offset to seek to |
127 | * @whence: type of seek |
128 | * |
129 | * This is a generic implemenation of ->llseek useable for all normal local |
130 | * filesystems. It just updates the file offset to the value specified by |
131 | * @offset and @whence under i_mutex. |
132 | */ |
133 | loff_t generic_file_llseek(struct file *file, loff_t offset, int whence) |
134 | { |
135 | struct inode *inode = file->f_mapping->host; |
136 | |
137 | return generic_file_llseek_size(file, offset, whence, |
138 | inode->i_sb->s_maxbytes, |
139 | i_size_read(inode)); |
140 | } |
141 | EXPORT_SYMBOL(generic_file_llseek); |
142 | |
143 | /** |
144 | * noop_llseek - No Operation Performed llseek implementation |
145 | * @file: file structure to seek on |
146 | * @offset: file offset to seek to |
147 | * @whence: type of seek |
148 | * |
149 | * This is an implementation of ->llseek useable for the rare special case when |
150 | * userspace expects the seek to succeed but the (device) file is actually not |
151 | * able to perform the seek. In this case you use noop_llseek() instead of |
152 | * falling back to the default implementation of ->llseek. |
153 | */ |
154 | loff_t noop_llseek(struct file *file, loff_t offset, int whence) |
155 | { |
156 | return file->f_pos; |
157 | } |
158 | EXPORT_SYMBOL(noop_llseek); |
159 | |
160 | loff_t no_llseek(struct file *file, loff_t offset, int whence) |
161 | { |
162 | return -ESPIPE; |
163 | } |
164 | EXPORT_SYMBOL(no_llseek); |
165 | |
166 | loff_t default_llseek(struct file *file, loff_t offset, int whence) |
167 | { |
168 | struct inode *inode = file_inode(file); |
169 | loff_t retval; |
170 | |
171 | mutex_lock(&inode->i_mutex); |
172 | switch (whence) { |
173 | case SEEK_END: |
174 | offset += i_size_read(inode); |
175 | break; |
176 | case SEEK_CUR: |
177 | if (offset == 0) { |
178 | retval = file->f_pos; |
179 | goto out; |
180 | } |
181 | offset += file->f_pos; |
182 | break; |
183 | case SEEK_DATA: |
184 | /* |
185 | * In the generic case the entire file is data, so as |
186 | * long as offset isn't at the end of the file then the |
187 | * offset is data. |
188 | */ |
189 | if (offset >= inode->i_size) { |
190 | retval = -ENXIO; |
191 | goto out; |
192 | } |
193 | break; |
194 | case SEEK_HOLE: |
195 | /* |
196 | * There is a virtual hole at the end of the file, so |
197 | * as long as offset isn't i_size or larger, return |
198 | * i_size. |
199 | */ |
200 | if (offset >= inode->i_size) { |
201 | retval = -ENXIO; |
202 | goto out; |
203 | } |
204 | offset = inode->i_size; |
205 | break; |
206 | } |
207 | retval = -EINVAL; |
208 | if (offset >= 0 || unsigned_offsets(file)) { |
209 | if (offset != file->f_pos) { |
210 | file->f_pos = offset; |
211 | file->f_version = 0; |
212 | } |
213 | retval = offset; |
214 | } |
215 | out: |
216 | mutex_unlock(&inode->i_mutex); |
217 | return retval; |
218 | } |
219 | EXPORT_SYMBOL(default_llseek); |
220 | |
221 | loff_t vfs_llseek(struct file *file, loff_t offset, int whence) |
222 | { |
223 | loff_t (*fn)(struct file *, loff_t, int); |
224 | |
225 | fn = no_llseek; |
226 | if (file->f_mode & FMODE_LSEEK) { |
227 | if (file->f_op && file->f_op->llseek) |
228 | fn = file->f_op->llseek; |
229 | } |
230 | return fn(file, offset, whence); |
231 | } |
232 | EXPORT_SYMBOL(vfs_llseek); |
233 | |
234 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence) |
235 | { |
236 | off_t retval; |
237 | struct fd f = fdget(fd); |
238 | if (!f.file) |
239 | return -EBADF; |
240 | |
241 | retval = -EINVAL; |
242 | if (whence <= SEEK_MAX) { |
243 | loff_t res = vfs_llseek(f.file, offset, whence); |
244 | retval = res; |
245 | if (res != (loff_t)retval) |
246 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ |
247 | } |
248 | fdput(f); |
249 | return retval; |
250 | } |
251 | |
252 | #ifdef CONFIG_COMPAT |
253 | COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence) |
254 | { |
255 | return sys_lseek(fd, offset, whence); |
256 | } |
257 | #endif |
258 | |
259 | #ifdef __ARCH_WANT_SYS_LLSEEK |
260 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, |
261 | unsigned long, offset_low, loff_t __user *, result, |
262 | unsigned int, whence) |
263 | { |
264 | int retval; |
265 | struct fd f = fdget(fd); |
266 | loff_t offset; |
267 | |
268 | if (!f.file) |
269 | return -EBADF; |
270 | |
271 | retval = -EINVAL; |
272 | if (whence > SEEK_MAX) |
273 | goto out_putf; |
274 | |
275 | offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low, |
276 | whence); |
277 | |
278 | retval = (int)offset; |
279 | if (offset >= 0) { |
280 | retval = -EFAULT; |
281 | if (!copy_to_user(result, &offset, sizeof(offset))) |
282 | retval = 0; |
283 | } |
284 | out_putf: |
285 | fdput(f); |
286 | return retval; |
287 | } |
288 | #endif |
289 | |
290 | /* |
291 | * rw_verify_area doesn't like huge counts. We limit |
292 | * them to something that fits in "int" so that others |
293 | * won't have to do range checks all the time. |
294 | */ |
295 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) |
296 | { |
297 | struct inode *inode; |
298 | loff_t pos; |
299 | int retval = -EINVAL; |
300 | |
301 | inode = file_inode(file); |
302 | if (unlikely((ssize_t) count < 0)) |
303 | return retval; |
304 | pos = *ppos; |
305 | if (unlikely(pos < 0)) { |
306 | if (!unsigned_offsets(file)) |
307 | return retval; |
308 | if (count >= -pos) /* both values are in 0..LLONG_MAX */ |
309 | return -EOVERFLOW; |
310 | } else if (unlikely((loff_t) (pos + count) < 0)) { |
311 | if (!unsigned_offsets(file)) |
312 | return retval; |
313 | } |
314 | |
315 | if (unlikely(inode->i_flock && mandatory_lock(inode))) { |
316 | retval = locks_mandatory_area( |
317 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, |
318 | inode, file, pos, count); |
319 | if (retval < 0) |
320 | return retval; |
321 | } |
322 | retval = security_file_permission(file, |
323 | read_write == READ ? MAY_READ : MAY_WRITE); |
324 | if (retval) |
325 | return retval; |
326 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; |
327 | } |
328 | |
329 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) |
330 | { |
331 | set_current_state(TASK_UNINTERRUPTIBLE); |
332 | if (!kiocbIsKicked(iocb)) |
333 | schedule(); |
334 | else |
335 | kiocbClearKicked(iocb); |
336 | __set_current_state(TASK_RUNNING); |
337 | } |
338 | |
339 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) |
340 | { |
341 | struct iovec iov = { .iov_base = buf, .iov_len = len }; |
342 | struct kiocb kiocb; |
343 | ssize_t ret; |
344 | |
345 | init_sync_kiocb(&kiocb, filp); |
346 | kiocb.ki_pos = *ppos; |
347 | kiocb.ki_left = len; |
348 | kiocb.ki_nbytes = len; |
349 | |
350 | for (;;) { |
351 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); |
352 | if (ret != -EIOCBRETRY) |
353 | break; |
354 | wait_on_retry_sync_kiocb(&kiocb); |
355 | } |
356 | |
357 | if (-EIOCBQUEUED == ret) |
358 | ret = wait_on_sync_kiocb(&kiocb); |
359 | *ppos = kiocb.ki_pos; |
360 | return ret; |
361 | } |
362 | |
363 | EXPORT_SYMBOL(do_sync_read); |
364 | |
365 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) |
366 | { |
367 | ssize_t ret; |
368 | |
369 | if (!(file->f_mode & FMODE_READ)) |
370 | return -EBADF; |
371 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) |
372 | return -EINVAL; |
373 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) |
374 | return -EFAULT; |
375 | |
376 | ret = rw_verify_area(READ, file, pos, count); |
377 | if (ret >= 0) { |
378 | count = ret; |
379 | if (file->f_op->read) |
380 | ret = file->f_op->read(file, buf, count, pos); |
381 | else |
382 | ret = do_sync_read(file, buf, count, pos); |
383 | if (ret > 0) { |
384 | fsnotify_access(file); |
385 | add_rchar(current, ret); |
386 | } |
387 | inc_syscr(current); |
388 | } |
389 | |
390 | return ret; |
391 | } |
392 | |
393 | EXPORT_SYMBOL(vfs_read); |
394 | |
395 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) |
396 | { |
397 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; |
398 | struct kiocb kiocb; |
399 | ssize_t ret; |
400 | |
401 | init_sync_kiocb(&kiocb, filp); |
402 | kiocb.ki_pos = *ppos; |
403 | kiocb.ki_left = len; |
404 | kiocb.ki_nbytes = len; |
405 | |
406 | for (;;) { |
407 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); |
408 | if (ret != -EIOCBRETRY) |
409 | break; |
410 | wait_on_retry_sync_kiocb(&kiocb); |
411 | } |
412 | |
413 | if (-EIOCBQUEUED == ret) |
414 | ret = wait_on_sync_kiocb(&kiocb); |
415 | *ppos = kiocb.ki_pos; |
416 | return ret; |
417 | } |
418 | |
419 | EXPORT_SYMBOL(do_sync_write); |
420 | |
421 | ssize_t __kernel_write(struct file *file, const char *buf, size_t count, loff_t *pos) |
422 | { |
423 | mm_segment_t old_fs; |
424 | const char __user *p; |
425 | ssize_t ret; |
426 | |
427 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) |
428 | return -EINVAL; |
429 | |
430 | old_fs = get_fs(); |
431 | set_fs(get_ds()); |
432 | p = (__force const char __user *)buf; |
433 | if (count > MAX_RW_COUNT) |
434 | count = MAX_RW_COUNT; |
435 | if (file->f_op->write) |
436 | ret = file->f_op->write(file, p, count, pos); |
437 | else |
438 | ret = do_sync_write(file, p, count, pos); |
439 | set_fs(old_fs); |
440 | if (ret > 0) { |
441 | fsnotify_modify(file); |
442 | add_wchar(current, ret); |
443 | } |
444 | inc_syscw(current); |
445 | return ret; |
446 | } |
447 | |
448 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
449 | { |
450 | ssize_t ret; |
451 | |
452 | if (!(file->f_mode & FMODE_WRITE)) |
453 | return -EBADF; |
454 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) |
455 | return -EINVAL; |
456 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) |
457 | return -EFAULT; |
458 | |
459 | ret = rw_verify_area(WRITE, file, pos, count); |
460 | if (ret >= 0) { |
461 | count = ret; |
462 | if (file->f_op->write) |
463 | ret = file->f_op->write(file, buf, count, pos); |
464 | else |
465 | ret = do_sync_write(file, buf, count, pos); |
466 | if (ret > 0) { |
467 | fsnotify_modify(file); |
468 | add_wchar(current, ret); |
469 | } |
470 | inc_syscw(current); |
471 | } |
472 | |
473 | return ret; |
474 | } |
475 | |
476 | EXPORT_SYMBOL(vfs_write); |
477 | |
478 | static inline loff_t file_pos_read(struct file *file) |
479 | { |
480 | return file->f_pos; |
481 | } |
482 | |
483 | static inline void file_pos_write(struct file *file, loff_t pos) |
484 | { |
485 | file->f_pos = pos; |
486 | } |
487 | |
488 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) |
489 | { |
490 | struct fd f = fdget(fd); |
491 | ssize_t ret = -EBADF; |
492 | |
493 | if (f.file) { |
494 | loff_t pos = file_pos_read(f.file); |
495 | ret = vfs_read(f.file, buf, count, &pos); |
496 | file_pos_write(f.file, pos); |
497 | fdput(f); |
498 | } |
499 | return ret; |
500 | } |
501 | |
502 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, |
503 | size_t, count) |
504 | { |
505 | struct fd f = fdget(fd); |
506 | ssize_t ret = -EBADF; |
507 | |
508 | if (f.file) { |
509 | loff_t pos = file_pos_read(f.file); |
510 | ret = vfs_write(f.file, buf, count, &pos); |
511 | file_pos_write(f.file, pos); |
512 | fdput(f); |
513 | } |
514 | |
515 | return ret; |
516 | } |
517 | |
518 | SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf, |
519 | size_t count, loff_t pos) |
520 | { |
521 | struct fd f; |
522 | ssize_t ret = -EBADF; |
523 | |
524 | if (pos < 0) |
525 | return -EINVAL; |
526 | |
527 | f = fdget(fd); |
528 | if (f.file) { |
529 | ret = -ESPIPE; |
530 | if (f.file->f_mode & FMODE_PREAD) |
531 | ret = vfs_read(f.file, buf, count, &pos); |
532 | fdput(f); |
533 | } |
534 | |
535 | return ret; |
536 | } |
537 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
538 | asmlinkage long SyS_pread64(long fd, long buf, long count, loff_t pos) |
539 | { |
540 | return SYSC_pread64((unsigned int) fd, (char __user *) buf, |
541 | (size_t) count, pos); |
542 | } |
543 | SYSCALL_ALIAS(sys_pread64, SyS_pread64); |
544 | #endif |
545 | |
546 | SYSCALL_DEFINE(pwrite64)(unsigned int fd, const char __user *buf, |
547 | size_t count, loff_t pos) |
548 | { |
549 | struct fd f; |
550 | ssize_t ret = -EBADF; |
551 | |
552 | if (pos < 0) |
553 | return -EINVAL; |
554 | |
555 | f = fdget(fd); |
556 | if (f.file) { |
557 | ret = -ESPIPE; |
558 | if (f.file->f_mode & FMODE_PWRITE) |
559 | ret = vfs_write(f.file, buf, count, &pos); |
560 | fdput(f); |
561 | } |
562 | |
563 | return ret; |
564 | } |
565 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
566 | asmlinkage long SyS_pwrite64(long fd, long buf, long count, loff_t pos) |
567 | { |
568 | return SYSC_pwrite64((unsigned int) fd, (const char __user *) buf, |
569 | (size_t) count, pos); |
570 | } |
571 | SYSCALL_ALIAS(sys_pwrite64, SyS_pwrite64); |
572 | #endif |
573 | |
574 | /* |
575 | * Reduce an iovec's length in-place. Return the resulting number of segments |
576 | */ |
577 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) |
578 | { |
579 | unsigned long seg = 0; |
580 | size_t len = 0; |
581 | |
582 | while (seg < nr_segs) { |
583 | seg++; |
584 | if (len + iov->iov_len >= to) { |
585 | iov->iov_len = to - len; |
586 | break; |
587 | } |
588 | len += iov->iov_len; |
589 | iov++; |
590 | } |
591 | return seg; |
592 | } |
593 | EXPORT_SYMBOL(iov_shorten); |
594 | |
595 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, |
596 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) |
597 | { |
598 | struct kiocb kiocb; |
599 | ssize_t ret; |
600 | |
601 | init_sync_kiocb(&kiocb, filp); |
602 | kiocb.ki_pos = *ppos; |
603 | kiocb.ki_left = len; |
604 | kiocb.ki_nbytes = len; |
605 | |
606 | for (;;) { |
607 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); |
608 | if (ret != -EIOCBRETRY) |
609 | break; |
610 | wait_on_retry_sync_kiocb(&kiocb); |
611 | } |
612 | |
613 | if (ret == -EIOCBQUEUED) |
614 | ret = wait_on_sync_kiocb(&kiocb); |
615 | *ppos = kiocb.ki_pos; |
616 | return ret; |
617 | } |
618 | |
619 | /* Do it by hand, with file-ops */ |
620 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, |
621 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) |
622 | { |
623 | struct iovec *vector = iov; |
624 | ssize_t ret = 0; |
625 | |
626 | while (nr_segs > 0) { |
627 | void __user *base; |
628 | size_t len; |
629 | ssize_t nr; |
630 | |
631 | base = vector->iov_base; |
632 | len = vector->iov_len; |
633 | vector++; |
634 | nr_segs--; |
635 | |
636 | nr = fn(filp, base, len, ppos); |
637 | |
638 | if (nr < 0) { |
639 | if (!ret) |
640 | ret = nr; |
641 | break; |
642 | } |
643 | ret += nr; |
644 | if (nr != len) |
645 | break; |
646 | } |
647 | |
648 | return ret; |
649 | } |
650 | |
651 | /* A write operation does a read from user space and vice versa */ |
652 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) |
653 | |
654 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, |
655 | unsigned long nr_segs, unsigned long fast_segs, |
656 | struct iovec *fast_pointer, |
657 | struct iovec **ret_pointer) |
658 | { |
659 | unsigned long seg; |
660 | ssize_t ret; |
661 | struct iovec *iov = fast_pointer; |
662 | |
663 | /* |
664 | * SuS says "The readv() function *may* fail if the iovcnt argument |
665 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has |
666 | * traditionally returned zero for zero segments, so... |
667 | */ |
668 | if (nr_segs == 0) { |
669 | ret = 0; |
670 | goto out; |
671 | } |
672 | |
673 | /* |
674 | * First get the "struct iovec" from user memory and |
675 | * verify all the pointers |
676 | */ |
677 | if (nr_segs > UIO_MAXIOV) { |
678 | ret = -EINVAL; |
679 | goto out; |
680 | } |
681 | if (nr_segs > fast_segs) { |
682 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); |
683 | if (iov == NULL) { |
684 | ret = -ENOMEM; |
685 | goto out; |
686 | } |
687 | } |
688 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { |
689 | ret = -EFAULT; |
690 | goto out; |
691 | } |
692 | |
693 | /* |
694 | * According to the Single Unix Specification we should return EINVAL |
695 | * if an element length is < 0 when cast to ssize_t or if the |
696 | * total length would overflow the ssize_t return value of the |
697 | * system call. |
698 | * |
699 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the |
700 | * overflow case. |
701 | */ |
702 | ret = 0; |
703 | for (seg = 0; seg < nr_segs; seg++) { |
704 | void __user *buf = iov[seg].iov_base; |
705 | ssize_t len = (ssize_t)iov[seg].iov_len; |
706 | |
707 | /* see if we we're about to use an invalid len or if |
708 | * it's about to overflow ssize_t */ |
709 | if (len < 0) { |
710 | ret = -EINVAL; |
711 | goto out; |
712 | } |
713 | if (type >= 0 |
714 | && unlikely(!access_ok(vrfy_dir(type), buf, len))) { |
715 | ret = -EFAULT; |
716 | goto out; |
717 | } |
718 | if (len > MAX_RW_COUNT - ret) { |
719 | len = MAX_RW_COUNT - ret; |
720 | iov[seg].iov_len = len; |
721 | } |
722 | ret += len; |
723 | } |
724 | out: |
725 | *ret_pointer = iov; |
726 | return ret; |
727 | } |
728 | |
729 | static ssize_t do_readv_writev(int type, struct file *file, |
730 | const struct iovec __user * uvector, |
731 | unsigned long nr_segs, loff_t *pos) |
732 | { |
733 | size_t tot_len; |
734 | struct iovec iovstack[UIO_FASTIOV]; |
735 | struct iovec *iov = iovstack; |
736 | ssize_t ret; |
737 | io_fn_t fn; |
738 | iov_fn_t fnv; |
739 | |
740 | if (!file->f_op) { |
741 | ret = -EINVAL; |
742 | goto out; |
743 | } |
744 | |
745 | ret = rw_copy_check_uvector(type, uvector, nr_segs, |
746 | ARRAY_SIZE(iovstack), iovstack, &iov); |
747 | if (ret <= 0) |
748 | goto out; |
749 | |
750 | tot_len = ret; |
751 | ret = rw_verify_area(type, file, pos, tot_len); |
752 | if (ret < 0) |
753 | goto out; |
754 | |
755 | fnv = NULL; |
756 | if (type == READ) { |
757 | fn = file->f_op->read; |
758 | fnv = file->f_op->aio_read; |
759 | } else { |
760 | fn = (io_fn_t)file->f_op->write; |
761 | fnv = file->f_op->aio_write; |
762 | } |
763 | |
764 | if (fnv) |
765 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, |
766 | pos, fnv); |
767 | else |
768 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); |
769 | |
770 | out: |
771 | if (iov != iovstack) |
772 | kfree(iov); |
773 | if ((ret + (type == READ)) > 0) { |
774 | if (type == READ) |
775 | fsnotify_access(file); |
776 | else |
777 | fsnotify_modify(file); |
778 | } |
779 | return ret; |
780 | } |
781 | |
782 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, |
783 | unsigned long vlen, loff_t *pos) |
784 | { |
785 | if (!(file->f_mode & FMODE_READ)) |
786 | return -EBADF; |
787 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) |
788 | return -EINVAL; |
789 | |
790 | return do_readv_writev(READ, file, vec, vlen, pos); |
791 | } |
792 | |
793 | EXPORT_SYMBOL(vfs_readv); |
794 | |
795 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, |
796 | unsigned long vlen, loff_t *pos) |
797 | { |
798 | if (!(file->f_mode & FMODE_WRITE)) |
799 | return -EBADF; |
800 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) |
801 | return -EINVAL; |
802 | |
803 | return do_readv_writev(WRITE, file, vec, vlen, pos); |
804 | } |
805 | |
806 | EXPORT_SYMBOL(vfs_writev); |
807 | |
808 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, |
809 | unsigned long, vlen) |
810 | { |
811 | struct fd f = fdget(fd); |
812 | ssize_t ret = -EBADF; |
813 | |
814 | if (f.file) { |
815 | loff_t pos = file_pos_read(f.file); |
816 | ret = vfs_readv(f.file, vec, vlen, &pos); |
817 | file_pos_write(f.file, pos); |
818 | fdput(f); |
819 | } |
820 | |
821 | if (ret > 0) |
822 | add_rchar(current, ret); |
823 | inc_syscr(current); |
824 | return ret; |
825 | } |
826 | |
827 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, |
828 | unsigned long, vlen) |
829 | { |
830 | struct fd f = fdget(fd); |
831 | ssize_t ret = -EBADF; |
832 | |
833 | if (f.file) { |
834 | loff_t pos = file_pos_read(f.file); |
835 | ret = vfs_writev(f.file, vec, vlen, &pos); |
836 | file_pos_write(f.file, pos); |
837 | fdput(f); |
838 | } |
839 | |
840 | if (ret > 0) |
841 | add_wchar(current, ret); |
842 | inc_syscw(current); |
843 | return ret; |
844 | } |
845 | |
846 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) |
847 | { |
848 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) |
849 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; |
850 | } |
851 | |
852 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, |
853 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
854 | { |
855 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
856 | struct fd f; |
857 | ssize_t ret = -EBADF; |
858 | |
859 | if (pos < 0) |
860 | return -EINVAL; |
861 | |
862 | f = fdget(fd); |
863 | if (f.file) { |
864 | ret = -ESPIPE; |
865 | if (f.file->f_mode & FMODE_PREAD) |
866 | ret = vfs_readv(f.file, vec, vlen, &pos); |
867 | fdput(f); |
868 | } |
869 | |
870 | if (ret > 0) |
871 | add_rchar(current, ret); |
872 | inc_syscr(current); |
873 | return ret; |
874 | } |
875 | |
876 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, |
877 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
878 | { |
879 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
880 | struct fd f; |
881 | ssize_t ret = -EBADF; |
882 | |
883 | if (pos < 0) |
884 | return -EINVAL; |
885 | |
886 | f = fdget(fd); |
887 | if (f.file) { |
888 | ret = -ESPIPE; |
889 | if (f.file->f_mode & FMODE_PWRITE) |
890 | ret = vfs_writev(f.file, vec, vlen, &pos); |
891 | fdput(f); |
892 | } |
893 | |
894 | if (ret > 0) |
895 | add_wchar(current, ret); |
896 | inc_syscw(current); |
897 | return ret; |
898 | } |
899 | |
900 | ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, size_t count, |
901 | loff_t max) |
902 | { |
903 | struct fd in, out; |
904 | struct inode *in_inode, *out_inode; |
905 | loff_t pos; |
906 | ssize_t retval; |
907 | int fl; |
908 | |
909 | /* |
910 | * Get input file, and verify that it is ok.. |
911 | */ |
912 | retval = -EBADF; |
913 | in = fdget(in_fd); |
914 | if (!in.file) |
915 | goto out; |
916 | if (!(in.file->f_mode & FMODE_READ)) |
917 | goto fput_in; |
918 | retval = -ESPIPE; |
919 | if (!ppos) |
920 | ppos = &in.file->f_pos; |
921 | else |
922 | if (!(in.file->f_mode & FMODE_PREAD)) |
923 | goto fput_in; |
924 | retval = rw_verify_area(READ, in.file, ppos, count); |
925 | if (retval < 0) |
926 | goto fput_in; |
927 | count = retval; |
928 | |
929 | /* |
930 | * Get output file, and verify that it is ok.. |
931 | */ |
932 | retval = -EBADF; |
933 | out = fdget(out_fd); |
934 | if (!out.file) |
935 | goto fput_in; |
936 | if (!(out.file->f_mode & FMODE_WRITE)) |
937 | goto fput_out; |
938 | retval = -EINVAL; |
939 | in_inode = file_inode(in.file); |
940 | out_inode = file_inode(out.file); |
941 | retval = rw_verify_area(WRITE, out.file, &out.file->f_pos, count); |
942 | if (retval < 0) |
943 | goto fput_out; |
944 | count = retval; |
945 | |
946 | if (!max) |
947 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); |
948 | |
949 | pos = *ppos; |
950 | if (unlikely(pos + count > max)) { |
951 | retval = -EOVERFLOW; |
952 | if (pos >= max) |
953 | goto fput_out; |
954 | count = max - pos; |
955 | } |
956 | |
957 | fl = 0; |
958 | #if 0 |
959 | /* |
960 | * We need to debate whether we can enable this or not. The |
961 | * man page documents EAGAIN return for the output at least, |
962 | * and the application is arguably buggy if it doesn't expect |
963 | * EAGAIN on a non-blocking file descriptor. |
964 | */ |
965 | if (in.file->f_flags & O_NONBLOCK) |
966 | fl = SPLICE_F_NONBLOCK; |
967 | #endif |
968 | retval = do_splice_direct(in.file, ppos, out.file, count, fl); |
969 | |
970 | if (retval > 0) { |
971 | add_rchar(current, retval); |
972 | add_wchar(current, retval); |
973 | fsnotify_access(in.file); |
974 | fsnotify_modify(out.file); |
975 | } |
976 | |
977 | inc_syscr(current); |
978 | inc_syscw(current); |
979 | if (*ppos > max) |
980 | retval = -EOVERFLOW; |
981 | |
982 | fput_out: |
983 | fdput(out); |
984 | fput_in: |
985 | fdput(in); |
986 | out: |
987 | return retval; |
988 | } |
989 | |
990 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) |
991 | { |
992 | loff_t pos; |
993 | off_t off; |
994 | ssize_t ret; |
995 | |
996 | if (offset) { |
997 | if (unlikely(get_user(off, offset))) |
998 | return -EFAULT; |
999 | pos = off; |
1000 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); |
1001 | if (unlikely(put_user(pos, offset))) |
1002 | return -EFAULT; |
1003 | return ret; |
1004 | } |
1005 | |
1006 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
1007 | } |
1008 | |
1009 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) |
1010 | { |
1011 | loff_t pos; |
1012 | ssize_t ret; |
1013 | |
1014 | if (offset) { |
1015 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) |
1016 | return -EFAULT; |
1017 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); |
1018 | if (unlikely(put_user(pos, offset))) |
1019 | return -EFAULT; |
1020 | return ret; |
1021 | } |
1022 | |
1023 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
1024 | } |
1025 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
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v3.9