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Commit | Line | Data |
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1da177e4 LT |
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> | |
0eeca283 | 12 | #include <linux/fsnotify.h> |
1da177e4 LT |
13 | #include <linux/security.h> |
14 | #include <linux/module.h> | |
15 | #include <linux/syscalls.h> | |
e28cc715 | 16 | #include <linux/pagemap.h> |
d6b29d7c | 17 | #include <linux/splice.h> |
ee0b3e67 | 18 | #include "read_write.h" |
1da177e4 LT |
19 | |
20 | #include <asm/uaccess.h> | |
21 | #include <asm/unistd.h> | |
22 | ||
4b6f5d20 | 23 | const struct file_operations generic_ro_fops = { |
1da177e4 | 24 | .llseek = generic_file_llseek, |
543ade1f BP |
25 | .read = do_sync_read, |
26 | .aio_read = generic_file_aio_read, | |
1da177e4 | 27 | .mmap = generic_file_readonly_mmap, |
534f2aaa | 28 | .splice_read = generic_file_splice_read, |
1da177e4 LT |
29 | }; |
30 | ||
31 | EXPORT_SYMBOL(generic_ro_fops); | |
32 | ||
4a3956c7 KH |
33 | static int |
34 | __negative_fpos_check(struct file *file, loff_t pos, size_t count) | |
35 | { | |
36 | /* | |
37 | * pos or pos+count is negative here, check overflow. | |
38 | * too big "count" will be caught in rw_verify_area(). | |
39 | */ | |
40 | if ((pos < 0) && (pos + count < pos)) | |
41 | return -EOVERFLOW; | |
42 | if (file->f_mode & FMODE_UNSIGNED_OFFSET) | |
43 | return 0; | |
44 | return -EINVAL; | |
45 | } | |
46 | ||
3a8cff4f CH |
47 | /** |
48 | * generic_file_llseek_unlocked - lockless generic llseek implementation | |
49 | * @file: file structure to seek on | |
50 | * @offset: file offset to seek to | |
51 | * @origin: type of seek | |
52 | * | |
53 | * Updates the file offset to the value specified by @offset and @origin. | |
54 | * Locking must be provided by the caller. | |
55 | */ | |
9465efc9 AK |
56 | loff_t |
57 | generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin) | |
1da177e4 | 58 | { |
1da177e4 LT |
59 | struct inode *inode = file->f_mapping->host; |
60 | ||
1da177e4 | 61 | switch (origin) { |
3a8cff4f CH |
62 | case SEEK_END: |
63 | offset += inode->i_size; | |
64 | break; | |
65 | case SEEK_CUR: | |
5b6f1eb9 AK |
66 | /* |
67 | * Here we special-case the lseek(fd, 0, SEEK_CUR) | |
68 | * position-querying operation. Avoid rewriting the "same" | |
69 | * f_pos value back to the file because a concurrent read(), | |
70 | * write() or lseek() might have altered it | |
71 | */ | |
72 | if (offset == 0) | |
73 | return file->f_pos; | |
3a8cff4f CH |
74 | offset += file->f_pos; |
75 | break; | |
1da177e4 | 76 | } |
3a8cff4f | 77 | |
4a3956c7 KH |
78 | if (offset < 0 && __negative_fpos_check(file, offset, 0)) |
79 | return -EINVAL; | |
80 | if (offset > inode->i_sb->s_maxbytes) | |
3a8cff4f CH |
81 | return -EINVAL; |
82 | ||
83 | /* Special lock needed here? */ | |
84 | if (offset != file->f_pos) { | |
85 | file->f_pos = offset; | |
86 | file->f_version = 0; | |
1da177e4 | 87 | } |
3a8cff4f CH |
88 | |
89 | return offset; | |
1da177e4 | 90 | } |
9465efc9 | 91 | EXPORT_SYMBOL(generic_file_llseek_unlocked); |
1da177e4 | 92 | |
3a8cff4f CH |
93 | /** |
94 | * generic_file_llseek - generic llseek implementation for regular files | |
95 | * @file: file structure to seek on | |
96 | * @offset: file offset to seek to | |
97 | * @origin: type of seek | |
98 | * | |
99 | * This is a generic implemenation of ->llseek useable for all normal local | |
100 | * filesystems. It just updates the file offset to the value specified by | |
101 | * @offset and @origin under i_mutex. | |
102 | */ | |
9465efc9 | 103 | loff_t generic_file_llseek(struct file *file, loff_t offset, int origin) |
1da177e4 | 104 | { |
3a8cff4f CH |
105 | loff_t rval; |
106 | ||
9465efc9 | 107 | mutex_lock(&file->f_dentry->d_inode->i_mutex); |
3a8cff4f | 108 | rval = generic_file_llseek_unlocked(file, offset, origin); |
9465efc9 | 109 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); |
3a8cff4f CH |
110 | |
111 | return rval; | |
1da177e4 | 112 | } |
9465efc9 | 113 | EXPORT_SYMBOL(generic_file_llseek); |
1da177e4 | 114 | |
ae6afc3f B |
115 | /** |
116 | * noop_llseek - No Operation Performed llseek implementation | |
117 | * @file: file structure to seek on | |
118 | * @offset: file offset to seek to | |
119 | * @origin: type of seek | |
120 | * | |
121 | * This is an implementation of ->llseek useable for the rare special case when | |
122 | * userspace expects the seek to succeed but the (device) file is actually not | |
123 | * able to perform the seek. In this case you use noop_llseek() instead of | |
124 | * falling back to the default implementation of ->llseek. | |
125 | */ | |
126 | loff_t noop_llseek(struct file *file, loff_t offset, int origin) | |
127 | { | |
128 | return file->f_pos; | |
129 | } | |
130 | EXPORT_SYMBOL(noop_llseek); | |
131 | ||
1da177e4 LT |
132 | loff_t no_llseek(struct file *file, loff_t offset, int origin) |
133 | { | |
134 | return -ESPIPE; | |
135 | } | |
136 | EXPORT_SYMBOL(no_llseek); | |
137 | ||
138 | loff_t default_llseek(struct file *file, loff_t offset, int origin) | |
139 | { | |
16abef0e | 140 | loff_t retval; |
1da177e4 | 141 | |
ab91261f | 142 | mutex_lock(&file->f_dentry->d_inode->i_mutex); |
1da177e4 | 143 | switch (origin) { |
7b8e8924 | 144 | case SEEK_END: |
0f7fc9e4 | 145 | offset += i_size_read(file->f_path.dentry->d_inode); |
1da177e4 | 146 | break; |
7b8e8924 | 147 | case SEEK_CUR: |
5b6f1eb9 AK |
148 | if (offset == 0) { |
149 | retval = file->f_pos; | |
150 | goto out; | |
151 | } | |
1da177e4 LT |
152 | offset += file->f_pos; |
153 | } | |
154 | retval = -EINVAL; | |
4a3956c7 | 155 | if (offset >= 0 || !__negative_fpos_check(file, offset, 0)) { |
1da177e4 LT |
156 | if (offset != file->f_pos) { |
157 | file->f_pos = offset; | |
158 | file->f_version = 0; | |
159 | } | |
160 | retval = offset; | |
161 | } | |
5b6f1eb9 | 162 | out: |
ab91261f | 163 | mutex_unlock(&file->f_dentry->d_inode->i_mutex); |
1da177e4 LT |
164 | return retval; |
165 | } | |
166 | EXPORT_SYMBOL(default_llseek); | |
167 | ||
168 | loff_t vfs_llseek(struct file *file, loff_t offset, int origin) | |
169 | { | |
170 | loff_t (*fn)(struct file *, loff_t, int); | |
171 | ||
172 | fn = no_llseek; | |
173 | if (file->f_mode & FMODE_LSEEK) { | |
1da177e4 LT |
174 | if (file->f_op && file->f_op->llseek) |
175 | fn = file->f_op->llseek; | |
176 | } | |
177 | return fn(file, offset, origin); | |
178 | } | |
179 | EXPORT_SYMBOL(vfs_llseek); | |
180 | ||
003d7ab4 | 181 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, origin) |
1da177e4 LT |
182 | { |
183 | off_t retval; | |
184 | struct file * file; | |
185 | int fput_needed; | |
186 | ||
187 | retval = -EBADF; | |
188 | file = fget_light(fd, &fput_needed); | |
189 | if (!file) | |
190 | goto bad; | |
191 | ||
192 | retval = -EINVAL; | |
1ae7075b | 193 | if (origin <= SEEK_MAX) { |
1da177e4 LT |
194 | loff_t res = vfs_llseek(file, offset, origin); |
195 | retval = res; | |
196 | if (res != (loff_t)retval) | |
197 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ | |
198 | } | |
199 | fput_light(file, fput_needed); | |
200 | bad: | |
201 | return retval; | |
202 | } | |
203 | ||
204 | #ifdef __ARCH_WANT_SYS_LLSEEK | |
003d7ab4 HC |
205 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, |
206 | unsigned long, offset_low, loff_t __user *, result, | |
207 | unsigned int, origin) | |
1da177e4 LT |
208 | { |
209 | int retval; | |
210 | struct file * file; | |
211 | loff_t offset; | |
212 | int fput_needed; | |
213 | ||
214 | retval = -EBADF; | |
215 | file = fget_light(fd, &fput_needed); | |
216 | if (!file) | |
217 | goto bad; | |
218 | ||
219 | retval = -EINVAL; | |
1ae7075b | 220 | if (origin > SEEK_MAX) |
1da177e4 LT |
221 | goto out_putf; |
222 | ||
223 | offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low, | |
224 | origin); | |
225 | ||
226 | retval = (int)offset; | |
227 | if (offset >= 0) { | |
228 | retval = -EFAULT; | |
229 | if (!copy_to_user(result, &offset, sizeof(offset))) | |
230 | retval = 0; | |
231 | } | |
232 | out_putf: | |
233 | fput_light(file, fput_needed); | |
234 | bad: | |
235 | return retval; | |
236 | } | |
237 | #endif | |
238 | ||
4a3956c7 | 239 | |
e28cc715 LT |
240 | /* |
241 | * rw_verify_area doesn't like huge counts. We limit | |
242 | * them to something that fits in "int" so that others | |
243 | * won't have to do range checks all the time. | |
244 | */ | |
1da177e4 LT |
245 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) |
246 | { | |
247 | struct inode *inode; | |
248 | loff_t pos; | |
c43e259c | 249 | int retval = -EINVAL; |
1da177e4 | 250 | |
163da958 | 251 | inode = file->f_path.dentry->d_inode; |
e28cc715 | 252 | if (unlikely((ssize_t) count < 0)) |
c43e259c | 253 | return retval; |
1da177e4 | 254 | pos = *ppos; |
4a3956c7 KH |
255 | if (unlikely((pos < 0) || (loff_t) (pos + count) < 0)) { |
256 | retval = __negative_fpos_check(file, pos, count); | |
257 | if (retval) | |
258 | return retval; | |
259 | } | |
1da177e4 | 260 | |
a16877ca | 261 | if (unlikely(inode->i_flock && mandatory_lock(inode))) { |
c43e259c | 262 | retval = locks_mandatory_area( |
e28cc715 LT |
263 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, |
264 | inode, file, pos, count); | |
265 | if (retval < 0) | |
266 | return retval; | |
267 | } | |
c43e259c JM |
268 | retval = security_file_permission(file, |
269 | read_write == READ ? MAY_READ : MAY_WRITE); | |
270 | if (retval) | |
271 | return retval; | |
e28cc715 | 272 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; |
1da177e4 LT |
273 | } |
274 | ||
63e68809 BL |
275 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) |
276 | { | |
277 | set_current_state(TASK_UNINTERRUPTIBLE); | |
278 | if (!kiocbIsKicked(iocb)) | |
279 | schedule(); | |
280 | else | |
281 | kiocbClearKicked(iocb); | |
282 | __set_current_state(TASK_RUNNING); | |
283 | } | |
284 | ||
1da177e4 LT |
285 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) |
286 | { | |
027445c3 | 287 | struct iovec iov = { .iov_base = buf, .iov_len = len }; |
1da177e4 LT |
288 | struct kiocb kiocb; |
289 | ssize_t ret; | |
290 | ||
291 | init_sync_kiocb(&kiocb, filp); | |
292 | kiocb.ki_pos = *ppos; | |
027445c3 | 293 | kiocb.ki_left = len; |
61964eba | 294 | kiocb.ki_nbytes = len; |
027445c3 BP |
295 | |
296 | for (;;) { | |
297 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); | |
298 | if (ret != -EIOCBRETRY) | |
299 | break; | |
63e68809 | 300 | wait_on_retry_sync_kiocb(&kiocb); |
027445c3 | 301 | } |
63e68809 | 302 | |
1da177e4 LT |
303 | if (-EIOCBQUEUED == ret) |
304 | ret = wait_on_sync_kiocb(&kiocb); | |
305 | *ppos = kiocb.ki_pos; | |
306 | return ret; | |
307 | } | |
308 | ||
309 | EXPORT_SYMBOL(do_sync_read); | |
310 | ||
311 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) | |
312 | { | |
313 | ssize_t ret; | |
314 | ||
315 | if (!(file->f_mode & FMODE_READ)) | |
316 | return -EBADF; | |
317 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) | |
318 | return -EINVAL; | |
319 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) | |
320 | return -EFAULT; | |
321 | ||
322 | ret = rw_verify_area(READ, file, pos, count); | |
e28cc715 LT |
323 | if (ret >= 0) { |
324 | count = ret; | |
c43e259c JM |
325 | if (file->f_op->read) |
326 | ret = file->f_op->read(file, buf, count, pos); | |
327 | else | |
328 | ret = do_sync_read(file, buf, count, pos); | |
329 | if (ret > 0) { | |
2a12a9d7 | 330 | fsnotify_access(file); |
c43e259c | 331 | add_rchar(current, ret); |
1da177e4 | 332 | } |
c43e259c | 333 | inc_syscr(current); |
1da177e4 LT |
334 | } |
335 | ||
336 | return ret; | |
337 | } | |
338 | ||
339 | EXPORT_SYMBOL(vfs_read); | |
340 | ||
341 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) | |
342 | { | |
027445c3 | 343 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; |
1da177e4 LT |
344 | struct kiocb kiocb; |
345 | ssize_t ret; | |
346 | ||
347 | init_sync_kiocb(&kiocb, filp); | |
348 | kiocb.ki_pos = *ppos; | |
027445c3 | 349 | kiocb.ki_left = len; |
61964eba | 350 | kiocb.ki_nbytes = len; |
027445c3 BP |
351 | |
352 | for (;;) { | |
353 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); | |
354 | if (ret != -EIOCBRETRY) | |
355 | break; | |
63e68809 | 356 | wait_on_retry_sync_kiocb(&kiocb); |
027445c3 | 357 | } |
63e68809 | 358 | |
1da177e4 LT |
359 | if (-EIOCBQUEUED == ret) |
360 | ret = wait_on_sync_kiocb(&kiocb); | |
361 | *ppos = kiocb.ki_pos; | |
362 | return ret; | |
363 | } | |
364 | ||
365 | EXPORT_SYMBOL(do_sync_write); | |
366 | ||
367 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) | |
368 | { | |
369 | ssize_t ret; | |
370 | ||
371 | if (!(file->f_mode & FMODE_WRITE)) | |
372 | return -EBADF; | |
373 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) | |
374 | return -EINVAL; | |
375 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) | |
376 | return -EFAULT; | |
377 | ||
378 | ret = rw_verify_area(WRITE, file, pos, count); | |
e28cc715 LT |
379 | if (ret >= 0) { |
380 | count = ret; | |
c43e259c JM |
381 | if (file->f_op->write) |
382 | ret = file->f_op->write(file, buf, count, pos); | |
383 | else | |
384 | ret = do_sync_write(file, buf, count, pos); | |
385 | if (ret > 0) { | |
2a12a9d7 | 386 | fsnotify_modify(file); |
c43e259c | 387 | add_wchar(current, ret); |
1da177e4 | 388 | } |
c43e259c | 389 | inc_syscw(current); |
1da177e4 LT |
390 | } |
391 | ||
392 | return ret; | |
393 | } | |
394 | ||
395 | EXPORT_SYMBOL(vfs_write); | |
396 | ||
397 | static inline loff_t file_pos_read(struct file *file) | |
398 | { | |
399 | return file->f_pos; | |
400 | } | |
401 | ||
402 | static inline void file_pos_write(struct file *file, loff_t pos) | |
403 | { | |
404 | file->f_pos = pos; | |
405 | } | |
406 | ||
3cdad428 | 407 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) |
1da177e4 LT |
408 | { |
409 | struct file *file; | |
410 | ssize_t ret = -EBADF; | |
411 | int fput_needed; | |
412 | ||
413 | file = fget_light(fd, &fput_needed); | |
414 | if (file) { | |
415 | loff_t pos = file_pos_read(file); | |
416 | ret = vfs_read(file, buf, count, &pos); | |
417 | file_pos_write(file, pos); | |
418 | fput_light(file, fput_needed); | |
419 | } | |
420 | ||
421 | return ret; | |
422 | } | |
1da177e4 | 423 | |
3cdad428 HC |
424 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, |
425 | size_t, count) | |
1da177e4 LT |
426 | { |
427 | struct file *file; | |
428 | ssize_t ret = -EBADF; | |
429 | int fput_needed; | |
430 | ||
431 | file = fget_light(fd, &fput_needed); | |
432 | if (file) { | |
433 | loff_t pos = file_pos_read(file); | |
434 | ret = vfs_write(file, buf, count, &pos); | |
435 | file_pos_write(file, pos); | |
436 | fput_light(file, fput_needed); | |
437 | } | |
438 | ||
439 | return ret; | |
440 | } | |
441 | ||
6673e0c3 HC |
442 | SYSCALL_DEFINE(pread64)(unsigned int fd, char __user *buf, |
443 | size_t count, loff_t pos) | |
1da177e4 LT |
444 | { |
445 | struct file *file; | |
446 | ssize_t ret = -EBADF; | |
447 | int fput_needed; | |
448 | ||
449 | if (pos < 0) | |
450 | return -EINVAL; | |
451 | ||
452 | file = fget_light(fd, &fput_needed); | |
453 | if (file) { | |
454 | ret = -ESPIPE; | |
455 | if (file->f_mode & FMODE_PREAD) | |
456 | ret = vfs_read(file, buf, count, &pos); | |
457 | fput_light(file, fput_needed); | |
458 | } | |
459 | ||
460 | return ret; | |
461 | } | |
6673e0c3 HC |
462 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
463 | asmlinkage long SyS_pread64(long fd, long buf, long count, loff_t pos) | |
464 | { | |
465 | return SYSC_pread64((unsigned int) fd, (char __user *) buf, | |
466 | (size_t) count, pos); | |
467 | } | |
468 | SYSCALL_ALIAS(sys_pread64, SyS_pread64); | |
469 | #endif | |
1da177e4 | 470 | |
6673e0c3 HC |
471 | SYSCALL_DEFINE(pwrite64)(unsigned int fd, const char __user *buf, |
472 | size_t count, loff_t pos) | |
1da177e4 LT |
473 | { |
474 | struct file *file; | |
475 | ssize_t ret = -EBADF; | |
476 | int fput_needed; | |
477 | ||
478 | if (pos < 0) | |
479 | return -EINVAL; | |
480 | ||
481 | file = fget_light(fd, &fput_needed); | |
482 | if (file) { | |
483 | ret = -ESPIPE; | |
484 | if (file->f_mode & FMODE_PWRITE) | |
485 | ret = vfs_write(file, buf, count, &pos); | |
486 | fput_light(file, fput_needed); | |
487 | } | |
488 | ||
489 | return ret; | |
490 | } | |
6673e0c3 HC |
491 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
492 | asmlinkage long SyS_pwrite64(long fd, long buf, long count, loff_t pos) | |
493 | { | |
494 | return SYSC_pwrite64((unsigned int) fd, (const char __user *) buf, | |
495 | (size_t) count, pos); | |
496 | } | |
497 | SYSCALL_ALIAS(sys_pwrite64, SyS_pwrite64); | |
498 | #endif | |
1da177e4 LT |
499 | |
500 | /* | |
501 | * Reduce an iovec's length in-place. Return the resulting number of segments | |
502 | */ | |
503 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) | |
504 | { | |
505 | unsigned long seg = 0; | |
506 | size_t len = 0; | |
507 | ||
508 | while (seg < nr_segs) { | |
509 | seg++; | |
510 | if (len + iov->iov_len >= to) { | |
511 | iov->iov_len = to - len; | |
512 | break; | |
513 | } | |
514 | len += iov->iov_len; | |
515 | iov++; | |
516 | } | |
517 | return seg; | |
518 | } | |
19295529 | 519 | EXPORT_SYMBOL(iov_shorten); |
1da177e4 | 520 | |
ee0b3e67 BP |
521 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, |
522 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) | |
523 | { | |
524 | struct kiocb kiocb; | |
525 | ssize_t ret; | |
526 | ||
527 | init_sync_kiocb(&kiocb, filp); | |
528 | kiocb.ki_pos = *ppos; | |
529 | kiocb.ki_left = len; | |
530 | kiocb.ki_nbytes = len; | |
531 | ||
532 | for (;;) { | |
533 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); | |
534 | if (ret != -EIOCBRETRY) | |
535 | break; | |
536 | wait_on_retry_sync_kiocb(&kiocb); | |
537 | } | |
538 | ||
539 | if (ret == -EIOCBQUEUED) | |
540 | ret = wait_on_sync_kiocb(&kiocb); | |
541 | *ppos = kiocb.ki_pos; | |
542 | return ret; | |
543 | } | |
544 | ||
545 | /* Do it by hand, with file-ops */ | |
546 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, | |
547 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) | |
548 | { | |
549 | struct iovec *vector = iov; | |
550 | ssize_t ret = 0; | |
551 | ||
552 | while (nr_segs > 0) { | |
553 | void __user *base; | |
554 | size_t len; | |
555 | ssize_t nr; | |
556 | ||
557 | base = vector->iov_base; | |
558 | len = vector->iov_len; | |
559 | vector++; | |
560 | nr_segs--; | |
561 | ||
562 | nr = fn(filp, base, len, ppos); | |
563 | ||
564 | if (nr < 0) { | |
565 | if (!ret) | |
566 | ret = nr; | |
567 | break; | |
568 | } | |
569 | ret += nr; | |
570 | if (nr != len) | |
571 | break; | |
572 | } | |
573 | ||
574 | return ret; | |
575 | } | |
576 | ||
1da177e4 LT |
577 | /* A write operation does a read from user space and vice versa */ |
578 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) | |
579 | ||
eed4e51f BP |
580 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, |
581 | unsigned long nr_segs, unsigned long fast_segs, | |
582 | struct iovec *fast_pointer, | |
583 | struct iovec **ret_pointer) | |
435f49a5 | 584 | { |
eed4e51f | 585 | unsigned long seg; |
435f49a5 | 586 | ssize_t ret; |
eed4e51f BP |
587 | struct iovec *iov = fast_pointer; |
588 | ||
435f49a5 LT |
589 | /* |
590 | * SuS says "The readv() function *may* fail if the iovcnt argument | |
591 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
592 | * traditionally returned zero for zero segments, so... | |
593 | */ | |
eed4e51f BP |
594 | if (nr_segs == 0) { |
595 | ret = 0; | |
435f49a5 | 596 | goto out; |
eed4e51f BP |
597 | } |
598 | ||
435f49a5 LT |
599 | /* |
600 | * First get the "struct iovec" from user memory and | |
601 | * verify all the pointers | |
602 | */ | |
eed4e51f BP |
603 | if (nr_segs > UIO_MAXIOV) { |
604 | ret = -EINVAL; | |
435f49a5 | 605 | goto out; |
eed4e51f BP |
606 | } |
607 | if (nr_segs > fast_segs) { | |
435f49a5 | 608 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); |
eed4e51f BP |
609 | if (iov == NULL) { |
610 | ret = -ENOMEM; | |
435f49a5 | 611 | goto out; |
eed4e51f | 612 | } |
435f49a5 | 613 | } |
eed4e51f BP |
614 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { |
615 | ret = -EFAULT; | |
435f49a5 | 616 | goto out; |
eed4e51f BP |
617 | } |
618 | ||
435f49a5 | 619 | /* |
eed4e51f BP |
620 | * According to the Single Unix Specification we should return EINVAL |
621 | * if an element length is < 0 when cast to ssize_t or if the | |
622 | * total length would overflow the ssize_t return value of the | |
623 | * system call. | |
435f49a5 LT |
624 | * |
625 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
626 | * overflow case. | |
627 | */ | |
eed4e51f | 628 | ret = 0; |
435f49a5 LT |
629 | for (seg = 0; seg < nr_segs; seg++) { |
630 | void __user *buf = iov[seg].iov_base; | |
631 | ssize_t len = (ssize_t)iov[seg].iov_len; | |
eed4e51f BP |
632 | |
633 | /* see if we we're about to use an invalid len or if | |
634 | * it's about to overflow ssize_t */ | |
435f49a5 | 635 | if (len < 0) { |
eed4e51f | 636 | ret = -EINVAL; |
435f49a5 | 637 | goto out; |
eed4e51f BP |
638 | } |
639 | if (unlikely(!access_ok(vrfy_dir(type), buf, len))) { | |
640 | ret = -EFAULT; | |
435f49a5 LT |
641 | goto out; |
642 | } | |
643 | if (len > MAX_RW_COUNT - ret) { | |
644 | len = MAX_RW_COUNT - ret; | |
645 | iov[seg].iov_len = len; | |
eed4e51f | 646 | } |
eed4e51f | 647 | ret += len; |
435f49a5 | 648 | } |
eed4e51f BP |
649 | out: |
650 | *ret_pointer = iov; | |
651 | return ret; | |
652 | } | |
653 | ||
1da177e4 LT |
654 | static ssize_t do_readv_writev(int type, struct file *file, |
655 | const struct iovec __user * uvector, | |
656 | unsigned long nr_segs, loff_t *pos) | |
657 | { | |
1da177e4 LT |
658 | size_t tot_len; |
659 | struct iovec iovstack[UIO_FASTIOV]; | |
ee0b3e67 | 660 | struct iovec *iov = iovstack; |
1da177e4 | 661 | ssize_t ret; |
1da177e4 LT |
662 | io_fn_t fn; |
663 | iov_fn_t fnv; | |
664 | ||
eed4e51f BP |
665 | if (!file->f_op) { |
666 | ret = -EINVAL; | |
1da177e4 | 667 | goto out; |
1da177e4 | 668 | } |
1da177e4 | 669 | |
eed4e51f BP |
670 | ret = rw_copy_check_uvector(type, uvector, nr_segs, |
671 | ARRAY_SIZE(iovstack), iovstack, &iov); | |
672 | if (ret <= 0) | |
1da177e4 | 673 | goto out; |
1da177e4 | 674 | |
eed4e51f | 675 | tot_len = ret; |
1da177e4 | 676 | ret = rw_verify_area(type, file, pos, tot_len); |
e28cc715 | 677 | if (ret < 0) |
411b67b4 | 678 | goto out; |
1da177e4 LT |
679 | |
680 | fnv = NULL; | |
681 | if (type == READ) { | |
682 | fn = file->f_op->read; | |
ee0b3e67 | 683 | fnv = file->f_op->aio_read; |
1da177e4 LT |
684 | } else { |
685 | fn = (io_fn_t)file->f_op->write; | |
ee0b3e67 | 686 | fnv = file->f_op->aio_write; |
1da177e4 LT |
687 | } |
688 | ||
ee0b3e67 BP |
689 | if (fnv) |
690 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, | |
691 | pos, fnv); | |
692 | else | |
693 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); | |
1da177e4 | 694 | |
1da177e4 LT |
695 | out: |
696 | if (iov != iovstack) | |
697 | kfree(iov); | |
0eeca283 RL |
698 | if ((ret + (type == READ)) > 0) { |
699 | if (type == READ) | |
2a12a9d7 | 700 | fsnotify_access(file); |
0eeca283 | 701 | else |
2a12a9d7 | 702 | fsnotify_modify(file); |
0eeca283 | 703 | } |
1da177e4 | 704 | return ret; |
1da177e4 LT |
705 | } |
706 | ||
707 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, | |
708 | unsigned long vlen, loff_t *pos) | |
709 | { | |
710 | if (!(file->f_mode & FMODE_READ)) | |
711 | return -EBADF; | |
ee0b3e67 | 712 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) |
1da177e4 LT |
713 | return -EINVAL; |
714 | ||
715 | return do_readv_writev(READ, file, vec, vlen, pos); | |
716 | } | |
717 | ||
718 | EXPORT_SYMBOL(vfs_readv); | |
719 | ||
720 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, | |
721 | unsigned long vlen, loff_t *pos) | |
722 | { | |
723 | if (!(file->f_mode & FMODE_WRITE)) | |
724 | return -EBADF; | |
ee0b3e67 | 725 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) |
1da177e4 LT |
726 | return -EINVAL; |
727 | ||
728 | return do_readv_writev(WRITE, file, vec, vlen, pos); | |
729 | } | |
730 | ||
731 | EXPORT_SYMBOL(vfs_writev); | |
732 | ||
3cdad428 HC |
733 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, |
734 | unsigned long, vlen) | |
1da177e4 LT |
735 | { |
736 | struct file *file; | |
737 | ssize_t ret = -EBADF; | |
738 | int fput_needed; | |
739 | ||
740 | file = fget_light(fd, &fput_needed); | |
741 | if (file) { | |
742 | loff_t pos = file_pos_read(file); | |
743 | ret = vfs_readv(file, vec, vlen, &pos); | |
744 | file_pos_write(file, pos); | |
745 | fput_light(file, fput_needed); | |
746 | } | |
747 | ||
748 | if (ret > 0) | |
4b98d11b AD |
749 | add_rchar(current, ret); |
750 | inc_syscr(current); | |
1da177e4 LT |
751 | return ret; |
752 | } | |
753 | ||
3cdad428 HC |
754 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, |
755 | unsigned long, vlen) | |
1da177e4 LT |
756 | { |
757 | struct file *file; | |
758 | ssize_t ret = -EBADF; | |
759 | int fput_needed; | |
760 | ||
761 | file = fget_light(fd, &fput_needed); | |
762 | if (file) { | |
763 | loff_t pos = file_pos_read(file); | |
764 | ret = vfs_writev(file, vec, vlen, &pos); | |
765 | file_pos_write(file, pos); | |
766 | fput_light(file, fput_needed); | |
767 | } | |
768 | ||
769 | if (ret > 0) | |
4b98d11b AD |
770 | add_wchar(current, ret); |
771 | inc_syscw(current); | |
1da177e4 LT |
772 | return ret; |
773 | } | |
774 | ||
601cc11d LT |
775 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) |
776 | { | |
777 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) | |
778 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; | |
779 | } | |
780 | ||
f3554f4b | 781 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, |
601cc11d | 782 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
f3554f4b | 783 | { |
601cc11d | 784 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
f3554f4b GH |
785 | struct file *file; |
786 | ssize_t ret = -EBADF; | |
787 | int fput_needed; | |
788 | ||
789 | if (pos < 0) | |
790 | return -EINVAL; | |
791 | ||
792 | file = fget_light(fd, &fput_needed); | |
793 | if (file) { | |
794 | ret = -ESPIPE; | |
795 | if (file->f_mode & FMODE_PREAD) | |
796 | ret = vfs_readv(file, vec, vlen, &pos); | |
797 | fput_light(file, fput_needed); | |
798 | } | |
799 | ||
800 | if (ret > 0) | |
801 | add_rchar(current, ret); | |
802 | inc_syscr(current); | |
803 | return ret; | |
804 | } | |
805 | ||
806 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, | |
601cc11d | 807 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
f3554f4b | 808 | { |
601cc11d | 809 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
f3554f4b GH |
810 | struct file *file; |
811 | ssize_t ret = -EBADF; | |
812 | int fput_needed; | |
813 | ||
814 | if (pos < 0) | |
815 | return -EINVAL; | |
816 | ||
817 | file = fget_light(fd, &fput_needed); | |
818 | if (file) { | |
819 | ret = -ESPIPE; | |
820 | if (file->f_mode & FMODE_PWRITE) | |
821 | ret = vfs_writev(file, vec, vlen, &pos); | |
822 | fput_light(file, fput_needed); | |
823 | } | |
824 | ||
825 | if (ret > 0) | |
826 | add_wchar(current, ret); | |
827 | inc_syscw(current); | |
828 | return ret; | |
829 | } | |
830 | ||
1da177e4 LT |
831 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, |
832 | size_t count, loff_t max) | |
833 | { | |
834 | struct file * in_file, * out_file; | |
835 | struct inode * in_inode, * out_inode; | |
836 | loff_t pos; | |
837 | ssize_t retval; | |
534f2aaa | 838 | int fput_needed_in, fput_needed_out, fl; |
1da177e4 LT |
839 | |
840 | /* | |
841 | * Get input file, and verify that it is ok.. | |
842 | */ | |
843 | retval = -EBADF; | |
844 | in_file = fget_light(in_fd, &fput_needed_in); | |
845 | if (!in_file) | |
846 | goto out; | |
847 | if (!(in_file->f_mode & FMODE_READ)) | |
848 | goto fput_in; | |
1da177e4 LT |
849 | retval = -ESPIPE; |
850 | if (!ppos) | |
851 | ppos = &in_file->f_pos; | |
852 | else | |
853 | if (!(in_file->f_mode & FMODE_PREAD)) | |
854 | goto fput_in; | |
855 | retval = rw_verify_area(READ, in_file, ppos, count); | |
e28cc715 | 856 | if (retval < 0) |
1da177e4 | 857 | goto fput_in; |
e28cc715 | 858 | count = retval; |
1da177e4 | 859 | |
1da177e4 LT |
860 | /* |
861 | * Get output file, and verify that it is ok.. | |
862 | */ | |
863 | retval = -EBADF; | |
864 | out_file = fget_light(out_fd, &fput_needed_out); | |
865 | if (!out_file) | |
866 | goto fput_in; | |
867 | if (!(out_file->f_mode & FMODE_WRITE)) | |
868 | goto fput_out; | |
869 | retval = -EINVAL; | |
6818173b | 870 | in_inode = in_file->f_path.dentry->d_inode; |
0f7fc9e4 | 871 | out_inode = out_file->f_path.dentry->d_inode; |
1da177e4 | 872 | retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count); |
e28cc715 | 873 | if (retval < 0) |
1da177e4 | 874 | goto fput_out; |
e28cc715 | 875 | count = retval; |
1da177e4 | 876 | |
1da177e4 LT |
877 | if (!max) |
878 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); | |
879 | ||
880 | pos = *ppos; | |
1da177e4 LT |
881 | if (unlikely(pos + count > max)) { |
882 | retval = -EOVERFLOW; | |
883 | if (pos >= max) | |
884 | goto fput_out; | |
885 | count = max - pos; | |
886 | } | |
887 | ||
d96e6e71 | 888 | fl = 0; |
534f2aaa | 889 | #if 0 |
d96e6e71 JA |
890 | /* |
891 | * We need to debate whether we can enable this or not. The | |
892 | * man page documents EAGAIN return for the output at least, | |
893 | * and the application is arguably buggy if it doesn't expect | |
894 | * EAGAIN on a non-blocking file descriptor. | |
895 | */ | |
896 | if (in_file->f_flags & O_NONBLOCK) | |
897 | fl = SPLICE_F_NONBLOCK; | |
534f2aaa | 898 | #endif |
d96e6e71 | 899 | retval = do_splice_direct(in_file, ppos, out_file, count, fl); |
1da177e4 LT |
900 | |
901 | if (retval > 0) { | |
4b98d11b AD |
902 | add_rchar(current, retval); |
903 | add_wchar(current, retval); | |
1da177e4 | 904 | } |
1da177e4 | 905 | |
4b98d11b AD |
906 | inc_syscr(current); |
907 | inc_syscw(current); | |
1da177e4 LT |
908 | if (*ppos > max) |
909 | retval = -EOVERFLOW; | |
910 | ||
911 | fput_out: | |
912 | fput_light(out_file, fput_needed_out); | |
913 | fput_in: | |
914 | fput_light(in_file, fput_needed_in); | |
915 | out: | |
916 | return retval; | |
917 | } | |
918 | ||
002c8976 | 919 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) |
1da177e4 LT |
920 | { |
921 | loff_t pos; | |
922 | off_t off; | |
923 | ssize_t ret; | |
924 | ||
925 | if (offset) { | |
926 | if (unlikely(get_user(off, offset))) | |
927 | return -EFAULT; | |
928 | pos = off; | |
929 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); | |
930 | if (unlikely(put_user(pos, offset))) | |
931 | return -EFAULT; | |
932 | return ret; | |
933 | } | |
934 | ||
935 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
936 | } | |
937 | ||
002c8976 | 938 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) |
1da177e4 LT |
939 | { |
940 | loff_t pos; | |
941 | ssize_t ret; | |
942 | ||
943 | if (offset) { | |
944 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) | |
945 | return -EFAULT; | |
946 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); | |
947 | if (unlikely(put_user(pos, offset))) | |
948 | return -EFAULT; | |
949 | return ret; | |
950 | } | |
951 | ||
952 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
953 | } |