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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 | 13 | #include <linux/security.h> |
630d9c47 | 14 | #include <linux/export.h> |
1da177e4 | 15 | #include <linux/syscalls.h> |
e28cc715 | 16 | #include <linux/pagemap.h> |
d6b29d7c | 17 | #include <linux/splice.h> |
561c6731 | 18 | #include <linux/compat.h> |
ee0b3e67 | 19 | #include "read_write.h" |
1da177e4 LT |
20 | |
21 | #include <asm/uaccess.h> | |
22 | #include <asm/unistd.h> | |
23 | ||
4b6f5d20 | 24 | const struct file_operations generic_ro_fops = { |
1da177e4 | 25 | .llseek = generic_file_llseek, |
543ade1f BP |
26 | .read = do_sync_read, |
27 | .aio_read = generic_file_aio_read, | |
1da177e4 | 28 | .mmap = generic_file_readonly_mmap, |
534f2aaa | 29 | .splice_read = generic_file_splice_read, |
1da177e4 LT |
30 | }; |
31 | ||
32 | EXPORT_SYMBOL(generic_ro_fops); | |
33 | ||
cccb5a1e | 34 | static inline int unsigned_offsets(struct file *file) |
4a3956c7 | 35 | { |
cccb5a1e | 36 | return file->f_mode & FMODE_UNSIGNED_OFFSET; |
4a3956c7 KH |
37 | } |
38 | ||
ef3d0fd2 AK |
39 | static loff_t lseek_execute(struct file *file, struct inode *inode, |
40 | loff_t offset, loff_t maxsize) | |
41 | { | |
42 | if (offset < 0 && !unsigned_offsets(file)) | |
43 | return -EINVAL; | |
44 | if (offset > maxsize) | |
45 | return -EINVAL; | |
46 | ||
47 | if (offset != file->f_pos) { | |
48 | file->f_pos = offset; | |
49 | file->f_version = 0; | |
50 | } | |
51 | return offset; | |
52 | } | |
53 | ||
3a8cff4f | 54 | /** |
5760495a | 55 | * generic_file_llseek_size - generic llseek implementation for regular files |
3a8cff4f CH |
56 | * @file: file structure to seek on |
57 | * @offset: file offset to seek to | |
965c8e59 | 58 | * @whence: type of seek |
e8b96eb5 ES |
59 | * @size: max size of this file in file system |
60 | * @eof: offset used for SEEK_END position | |
3a8cff4f | 61 | * |
5760495a | 62 | * This is a variant of generic_file_llseek that allows passing in a custom |
e8b96eb5 | 63 | * maximum file size and a custom EOF position, for e.g. hashed directories |
ef3d0fd2 AK |
64 | * |
65 | * Synchronization: | |
5760495a | 66 | * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms) |
ef3d0fd2 AK |
67 | * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes. |
68 | * read/writes behave like SEEK_SET against seeks. | |
3a8cff4f | 69 | */ |
9465efc9 | 70 | loff_t |
965c8e59 | 71 | generic_file_llseek_size(struct file *file, loff_t offset, int whence, |
e8b96eb5 | 72 | loff_t maxsize, loff_t eof) |
1da177e4 | 73 | { |
1da177e4 LT |
74 | struct inode *inode = file->f_mapping->host; |
75 | ||
965c8e59 | 76 | switch (whence) { |
3a8cff4f | 77 | case SEEK_END: |
e8b96eb5 | 78 | offset += eof; |
3a8cff4f CH |
79 | break; |
80 | case SEEK_CUR: | |
5b6f1eb9 AK |
81 | /* |
82 | * Here we special-case the lseek(fd, 0, SEEK_CUR) | |
83 | * position-querying operation. Avoid rewriting the "same" | |
84 | * f_pos value back to the file because a concurrent read(), | |
85 | * write() or lseek() might have altered it | |
86 | */ | |
87 | if (offset == 0) | |
88 | return file->f_pos; | |
ef3d0fd2 AK |
89 | /* |
90 | * f_lock protects against read/modify/write race with other | |
91 | * SEEK_CURs. Note that parallel writes and reads behave | |
92 | * like SEEK_SET. | |
93 | */ | |
94 | spin_lock(&file->f_lock); | |
95 | offset = lseek_execute(file, inode, file->f_pos + offset, | |
5760495a | 96 | maxsize); |
ef3d0fd2 AK |
97 | spin_unlock(&file->f_lock); |
98 | return offset; | |
982d8165 JB |
99 | case SEEK_DATA: |
100 | /* | |
101 | * In the generic case the entire file is data, so as long as | |
102 | * offset isn't at the end of the file then the offset is data. | |
103 | */ | |
e8b96eb5 | 104 | if (offset >= eof) |
982d8165 JB |
105 | return -ENXIO; |
106 | break; | |
107 | case SEEK_HOLE: | |
108 | /* | |
109 | * There is a virtual hole at the end of the file, so as long as | |
110 | * offset isn't i_size or larger, return i_size. | |
111 | */ | |
e8b96eb5 | 112 | if (offset >= eof) |
982d8165 | 113 | return -ENXIO; |
e8b96eb5 | 114 | offset = eof; |
982d8165 | 115 | break; |
1da177e4 | 116 | } |
3a8cff4f | 117 | |
5760495a AK |
118 | return lseek_execute(file, inode, offset, maxsize); |
119 | } | |
120 | EXPORT_SYMBOL(generic_file_llseek_size); | |
121 | ||
122 | /** | |
123 | * generic_file_llseek - generic llseek implementation for regular files | |
124 | * @file: file structure to seek on | |
125 | * @offset: file offset to seek to | |
965c8e59 | 126 | * @whence: type of seek |
5760495a AK |
127 | * |
128 | * This is a generic implemenation of ->llseek useable for all normal local | |
129 | * filesystems. It just updates the file offset to the value specified by | |
965c8e59 | 130 | * @offset and @whence under i_mutex. |
5760495a | 131 | */ |
965c8e59 | 132 | loff_t generic_file_llseek(struct file *file, loff_t offset, int whence) |
5760495a AK |
133 | { |
134 | struct inode *inode = file->f_mapping->host; | |
135 | ||
965c8e59 | 136 | return generic_file_llseek_size(file, offset, whence, |
e8b96eb5 ES |
137 | inode->i_sb->s_maxbytes, |
138 | i_size_read(inode)); | |
1da177e4 | 139 | } |
9465efc9 | 140 | EXPORT_SYMBOL(generic_file_llseek); |
1da177e4 | 141 | |
ae6afc3f B |
142 | /** |
143 | * noop_llseek - No Operation Performed llseek implementation | |
144 | * @file: file structure to seek on | |
145 | * @offset: file offset to seek to | |
965c8e59 | 146 | * @whence: type of seek |
ae6afc3f B |
147 | * |
148 | * This is an implementation of ->llseek useable for the rare special case when | |
149 | * userspace expects the seek to succeed but the (device) file is actually not | |
150 | * able to perform the seek. In this case you use noop_llseek() instead of | |
151 | * falling back to the default implementation of ->llseek. | |
152 | */ | |
965c8e59 | 153 | loff_t noop_llseek(struct file *file, loff_t offset, int whence) |
ae6afc3f B |
154 | { |
155 | return file->f_pos; | |
156 | } | |
157 | EXPORT_SYMBOL(noop_llseek); | |
158 | ||
965c8e59 | 159 | loff_t no_llseek(struct file *file, loff_t offset, int whence) |
1da177e4 LT |
160 | { |
161 | return -ESPIPE; | |
162 | } | |
163 | EXPORT_SYMBOL(no_llseek); | |
164 | ||
965c8e59 | 165 | loff_t default_llseek(struct file *file, loff_t offset, int whence) |
1da177e4 | 166 | { |
496ad9aa | 167 | struct inode *inode = file_inode(file); |
16abef0e | 168 | loff_t retval; |
1da177e4 | 169 | |
982d8165 | 170 | mutex_lock(&inode->i_mutex); |
965c8e59 | 171 | switch (whence) { |
7b8e8924 | 172 | case SEEK_END: |
982d8165 | 173 | offset += i_size_read(inode); |
1da177e4 | 174 | break; |
7b8e8924 | 175 | case SEEK_CUR: |
5b6f1eb9 AK |
176 | if (offset == 0) { |
177 | retval = file->f_pos; | |
178 | goto out; | |
179 | } | |
1da177e4 | 180 | offset += file->f_pos; |
982d8165 JB |
181 | break; |
182 | case SEEK_DATA: | |
183 | /* | |
184 | * In the generic case the entire file is data, so as | |
185 | * long as offset isn't at the end of the file then the | |
186 | * offset is data. | |
187 | */ | |
bacb2d81 DC |
188 | if (offset >= inode->i_size) { |
189 | retval = -ENXIO; | |
190 | goto out; | |
191 | } | |
982d8165 JB |
192 | break; |
193 | case SEEK_HOLE: | |
194 | /* | |
195 | * There is a virtual hole at the end of the file, so | |
196 | * as long as offset isn't i_size or larger, return | |
197 | * i_size. | |
198 | */ | |
bacb2d81 DC |
199 | if (offset >= inode->i_size) { |
200 | retval = -ENXIO; | |
201 | goto out; | |
202 | } | |
982d8165 JB |
203 | offset = inode->i_size; |
204 | break; | |
1da177e4 LT |
205 | } |
206 | retval = -EINVAL; | |
cccb5a1e | 207 | if (offset >= 0 || unsigned_offsets(file)) { |
1da177e4 LT |
208 | if (offset != file->f_pos) { |
209 | file->f_pos = offset; | |
210 | file->f_version = 0; | |
211 | } | |
212 | retval = offset; | |
213 | } | |
5b6f1eb9 | 214 | out: |
982d8165 | 215 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
216 | return retval; |
217 | } | |
218 | EXPORT_SYMBOL(default_llseek); | |
219 | ||
965c8e59 | 220 | loff_t vfs_llseek(struct file *file, loff_t offset, int whence) |
1da177e4 LT |
221 | { |
222 | loff_t (*fn)(struct file *, loff_t, int); | |
223 | ||
224 | fn = no_llseek; | |
225 | if (file->f_mode & FMODE_LSEEK) { | |
1da177e4 LT |
226 | if (file->f_op && file->f_op->llseek) |
227 | fn = file->f_op->llseek; | |
228 | } | |
965c8e59 | 229 | return fn(file, offset, whence); |
1da177e4 LT |
230 | } |
231 | EXPORT_SYMBOL(vfs_llseek); | |
232 | ||
965c8e59 | 233 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence) |
1da177e4 LT |
234 | { |
235 | off_t retval; | |
2903ff01 AV |
236 | struct fd f = fdget(fd); |
237 | if (!f.file) | |
238 | return -EBADF; | |
1da177e4 LT |
239 | |
240 | retval = -EINVAL; | |
965c8e59 AM |
241 | if (whence <= SEEK_MAX) { |
242 | loff_t res = vfs_llseek(f.file, offset, whence); | |
1da177e4 LT |
243 | retval = res; |
244 | if (res != (loff_t)retval) | |
245 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ | |
246 | } | |
2903ff01 | 247 | fdput(f); |
1da177e4 LT |
248 | return retval; |
249 | } | |
250 | ||
561c6731 AV |
251 | #ifdef CONFIG_COMPAT |
252 | COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence) | |
253 | { | |
254 | return sys_lseek(fd, offset, whence); | |
255 | } | |
256 | #endif | |
257 | ||
1da177e4 | 258 | #ifdef __ARCH_WANT_SYS_LLSEEK |
003d7ab4 HC |
259 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, |
260 | unsigned long, offset_low, loff_t __user *, result, | |
965c8e59 | 261 | unsigned int, whence) |
1da177e4 LT |
262 | { |
263 | int retval; | |
2903ff01 | 264 | struct fd f = fdget(fd); |
1da177e4 | 265 | loff_t offset; |
1da177e4 | 266 | |
2903ff01 AV |
267 | if (!f.file) |
268 | return -EBADF; | |
1da177e4 LT |
269 | |
270 | retval = -EINVAL; | |
965c8e59 | 271 | if (whence > SEEK_MAX) |
1da177e4 LT |
272 | goto out_putf; |
273 | ||
2903ff01 | 274 | offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low, |
965c8e59 | 275 | whence); |
1da177e4 LT |
276 | |
277 | retval = (int)offset; | |
278 | if (offset >= 0) { | |
279 | retval = -EFAULT; | |
280 | if (!copy_to_user(result, &offset, sizeof(offset))) | |
281 | retval = 0; | |
282 | } | |
283 | out_putf: | |
2903ff01 | 284 | fdput(f); |
1da177e4 LT |
285 | return retval; |
286 | } | |
287 | #endif | |
288 | ||
e28cc715 LT |
289 | /* |
290 | * rw_verify_area doesn't like huge counts. We limit | |
291 | * them to something that fits in "int" so that others | |
292 | * won't have to do range checks all the time. | |
293 | */ | |
1da177e4 LT |
294 | int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count) |
295 | { | |
296 | struct inode *inode; | |
297 | loff_t pos; | |
c43e259c | 298 | int retval = -EINVAL; |
1da177e4 | 299 | |
496ad9aa | 300 | inode = file_inode(file); |
e28cc715 | 301 | if (unlikely((ssize_t) count < 0)) |
c43e259c | 302 | return retval; |
1da177e4 | 303 | pos = *ppos; |
cccb5a1e AV |
304 | if (unlikely(pos < 0)) { |
305 | if (!unsigned_offsets(file)) | |
306 | return retval; | |
307 | if (count >= -pos) /* both values are in 0..LLONG_MAX */ | |
308 | return -EOVERFLOW; | |
309 | } else if (unlikely((loff_t) (pos + count) < 0)) { | |
310 | if (!unsigned_offsets(file)) | |
4a3956c7 KH |
311 | return retval; |
312 | } | |
1da177e4 | 313 | |
a16877ca | 314 | if (unlikely(inode->i_flock && mandatory_lock(inode))) { |
c43e259c | 315 | retval = locks_mandatory_area( |
e28cc715 LT |
316 | read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, |
317 | inode, file, pos, count); | |
318 | if (retval < 0) | |
319 | return retval; | |
320 | } | |
c43e259c JM |
321 | retval = security_file_permission(file, |
322 | read_write == READ ? MAY_READ : MAY_WRITE); | |
323 | if (retval) | |
324 | return retval; | |
e28cc715 | 325 | return count > MAX_RW_COUNT ? MAX_RW_COUNT : count; |
1da177e4 LT |
326 | } |
327 | ||
63e68809 BL |
328 | static void wait_on_retry_sync_kiocb(struct kiocb *iocb) |
329 | { | |
330 | set_current_state(TASK_UNINTERRUPTIBLE); | |
331 | if (!kiocbIsKicked(iocb)) | |
332 | schedule(); | |
333 | else | |
334 | kiocbClearKicked(iocb); | |
335 | __set_current_state(TASK_RUNNING); | |
336 | } | |
337 | ||
1da177e4 LT |
338 | ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) |
339 | { | |
027445c3 | 340 | struct iovec iov = { .iov_base = buf, .iov_len = len }; |
1da177e4 LT |
341 | struct kiocb kiocb; |
342 | ssize_t ret; | |
343 | ||
344 | init_sync_kiocb(&kiocb, filp); | |
345 | kiocb.ki_pos = *ppos; | |
027445c3 | 346 | kiocb.ki_left = len; |
61964eba | 347 | kiocb.ki_nbytes = len; |
027445c3 BP |
348 | |
349 | for (;;) { | |
350 | ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos); | |
351 | if (ret != -EIOCBRETRY) | |
352 | break; | |
63e68809 | 353 | wait_on_retry_sync_kiocb(&kiocb); |
027445c3 | 354 | } |
63e68809 | 355 | |
1da177e4 LT |
356 | if (-EIOCBQUEUED == ret) |
357 | ret = wait_on_sync_kiocb(&kiocb); | |
358 | *ppos = kiocb.ki_pos; | |
359 | return ret; | |
360 | } | |
361 | ||
362 | EXPORT_SYMBOL(do_sync_read); | |
363 | ||
364 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) | |
365 | { | |
366 | ssize_t ret; | |
367 | ||
368 | if (!(file->f_mode & FMODE_READ)) | |
369 | return -EBADF; | |
370 | if (!file->f_op || (!file->f_op->read && !file->f_op->aio_read)) | |
371 | return -EINVAL; | |
372 | if (unlikely(!access_ok(VERIFY_WRITE, buf, count))) | |
373 | return -EFAULT; | |
374 | ||
375 | ret = rw_verify_area(READ, file, pos, count); | |
e28cc715 LT |
376 | if (ret >= 0) { |
377 | count = ret; | |
c43e259c JM |
378 | if (file->f_op->read) |
379 | ret = file->f_op->read(file, buf, count, pos); | |
380 | else | |
381 | ret = do_sync_read(file, buf, count, pos); | |
382 | if (ret > 0) { | |
2a12a9d7 | 383 | fsnotify_access(file); |
c43e259c | 384 | add_rchar(current, ret); |
1da177e4 | 385 | } |
c43e259c | 386 | inc_syscr(current); |
1da177e4 LT |
387 | } |
388 | ||
389 | return ret; | |
390 | } | |
391 | ||
392 | EXPORT_SYMBOL(vfs_read); | |
393 | ||
394 | ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) | |
395 | { | |
027445c3 | 396 | struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len }; |
1da177e4 LT |
397 | struct kiocb kiocb; |
398 | ssize_t ret; | |
399 | ||
400 | init_sync_kiocb(&kiocb, filp); | |
401 | kiocb.ki_pos = *ppos; | |
027445c3 | 402 | kiocb.ki_left = len; |
61964eba | 403 | kiocb.ki_nbytes = len; |
027445c3 BP |
404 | |
405 | for (;;) { | |
406 | ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos); | |
407 | if (ret != -EIOCBRETRY) | |
408 | break; | |
63e68809 | 409 | wait_on_retry_sync_kiocb(&kiocb); |
027445c3 | 410 | } |
63e68809 | 411 | |
1da177e4 LT |
412 | if (-EIOCBQUEUED == ret) |
413 | ret = wait_on_sync_kiocb(&kiocb); | |
414 | *ppos = kiocb.ki_pos; | |
415 | return ret; | |
416 | } | |
417 | ||
418 | EXPORT_SYMBOL(do_sync_write); | |
419 | ||
420 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) | |
421 | { | |
422 | ssize_t ret; | |
423 | ||
424 | if (!(file->f_mode & FMODE_WRITE)) | |
425 | return -EBADF; | |
426 | if (!file->f_op || (!file->f_op->write && !file->f_op->aio_write)) | |
427 | return -EINVAL; | |
428 | if (unlikely(!access_ok(VERIFY_READ, buf, count))) | |
429 | return -EFAULT; | |
430 | ||
431 | ret = rw_verify_area(WRITE, file, pos, count); | |
e28cc715 LT |
432 | if (ret >= 0) { |
433 | count = ret; | |
c43e259c JM |
434 | if (file->f_op->write) |
435 | ret = file->f_op->write(file, buf, count, pos); | |
436 | else | |
437 | ret = do_sync_write(file, buf, count, pos); | |
438 | if (ret > 0) { | |
2a12a9d7 | 439 | fsnotify_modify(file); |
c43e259c | 440 | add_wchar(current, ret); |
1da177e4 | 441 | } |
c43e259c | 442 | inc_syscw(current); |
1da177e4 LT |
443 | } |
444 | ||
445 | return ret; | |
446 | } | |
447 | ||
448 | EXPORT_SYMBOL(vfs_write); | |
449 | ||
450 | static inline loff_t file_pos_read(struct file *file) | |
451 | { | |
452 | return file->f_pos; | |
453 | } | |
454 | ||
455 | static inline void file_pos_write(struct file *file, loff_t pos) | |
456 | { | |
457 | file->f_pos = pos; | |
458 | } | |
459 | ||
3cdad428 | 460 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) |
1da177e4 | 461 | { |
2903ff01 | 462 | struct fd f = fdget(fd); |
1da177e4 | 463 | ssize_t ret = -EBADF; |
1da177e4 | 464 | |
2903ff01 AV |
465 | if (f.file) { |
466 | loff_t pos = file_pos_read(f.file); | |
467 | ret = vfs_read(f.file, buf, count, &pos); | |
468 | file_pos_write(f.file, pos); | |
469 | fdput(f); | |
1da177e4 | 470 | } |
1da177e4 LT |
471 | return ret; |
472 | } | |
1da177e4 | 473 | |
3cdad428 HC |
474 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, |
475 | size_t, count) | |
1da177e4 | 476 | { |
2903ff01 | 477 | struct fd f = fdget(fd); |
1da177e4 | 478 | ssize_t ret = -EBADF; |
1da177e4 | 479 | |
2903ff01 AV |
480 | if (f.file) { |
481 | loff_t pos = file_pos_read(f.file); | |
482 | ret = vfs_write(f.file, buf, count, &pos); | |
483 | file_pos_write(f.file, pos); | |
484 | fdput(f); | |
1da177e4 LT |
485 | } |
486 | ||
487 | return ret; | |
488 | } | |
489 | ||
4a0fd5bf AV |
490 | SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf, |
491 | size_t, count, loff_t, pos) | |
1da177e4 | 492 | { |
2903ff01 | 493 | struct fd f; |
1da177e4 | 494 | ssize_t ret = -EBADF; |
1da177e4 LT |
495 | |
496 | if (pos < 0) | |
497 | return -EINVAL; | |
498 | ||
2903ff01 AV |
499 | f = fdget(fd); |
500 | if (f.file) { | |
1da177e4 | 501 | ret = -ESPIPE; |
2903ff01 AV |
502 | if (f.file->f_mode & FMODE_PREAD) |
503 | ret = vfs_read(f.file, buf, count, &pos); | |
504 | fdput(f); | |
1da177e4 LT |
505 | } |
506 | ||
507 | return ret; | |
508 | } | |
509 | ||
4a0fd5bf AV |
510 | SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf, |
511 | size_t, count, loff_t, pos) | |
1da177e4 | 512 | { |
2903ff01 | 513 | struct fd f; |
1da177e4 | 514 | ssize_t ret = -EBADF; |
1da177e4 LT |
515 | |
516 | if (pos < 0) | |
517 | return -EINVAL; | |
518 | ||
2903ff01 AV |
519 | f = fdget(fd); |
520 | if (f.file) { | |
1da177e4 | 521 | ret = -ESPIPE; |
2903ff01 AV |
522 | if (f.file->f_mode & FMODE_PWRITE) |
523 | ret = vfs_write(f.file, buf, count, &pos); | |
524 | fdput(f); | |
1da177e4 LT |
525 | } |
526 | ||
527 | return ret; | |
528 | } | |
529 | ||
530 | /* | |
531 | * Reduce an iovec's length in-place. Return the resulting number of segments | |
532 | */ | |
533 | unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to) | |
534 | { | |
535 | unsigned long seg = 0; | |
536 | size_t len = 0; | |
537 | ||
538 | while (seg < nr_segs) { | |
539 | seg++; | |
540 | if (len + iov->iov_len >= to) { | |
541 | iov->iov_len = to - len; | |
542 | break; | |
543 | } | |
544 | len += iov->iov_len; | |
545 | iov++; | |
546 | } | |
547 | return seg; | |
548 | } | |
19295529 | 549 | EXPORT_SYMBOL(iov_shorten); |
1da177e4 | 550 | |
ee0b3e67 BP |
551 | ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov, |
552 | unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn) | |
553 | { | |
554 | struct kiocb kiocb; | |
555 | ssize_t ret; | |
556 | ||
557 | init_sync_kiocb(&kiocb, filp); | |
558 | kiocb.ki_pos = *ppos; | |
559 | kiocb.ki_left = len; | |
560 | kiocb.ki_nbytes = len; | |
561 | ||
562 | for (;;) { | |
563 | ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos); | |
564 | if (ret != -EIOCBRETRY) | |
565 | break; | |
566 | wait_on_retry_sync_kiocb(&kiocb); | |
567 | } | |
568 | ||
569 | if (ret == -EIOCBQUEUED) | |
570 | ret = wait_on_sync_kiocb(&kiocb); | |
571 | *ppos = kiocb.ki_pos; | |
572 | return ret; | |
573 | } | |
574 | ||
575 | /* Do it by hand, with file-ops */ | |
576 | ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov, | |
577 | unsigned long nr_segs, loff_t *ppos, io_fn_t fn) | |
578 | { | |
579 | struct iovec *vector = iov; | |
580 | ssize_t ret = 0; | |
581 | ||
582 | while (nr_segs > 0) { | |
583 | void __user *base; | |
584 | size_t len; | |
585 | ssize_t nr; | |
586 | ||
587 | base = vector->iov_base; | |
588 | len = vector->iov_len; | |
589 | vector++; | |
590 | nr_segs--; | |
591 | ||
592 | nr = fn(filp, base, len, ppos); | |
593 | ||
594 | if (nr < 0) { | |
595 | if (!ret) | |
596 | ret = nr; | |
597 | break; | |
598 | } | |
599 | ret += nr; | |
600 | if (nr != len) | |
601 | break; | |
602 | } | |
603 | ||
604 | return ret; | |
605 | } | |
606 | ||
1da177e4 LT |
607 | /* A write operation does a read from user space and vice versa */ |
608 | #define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ) | |
609 | ||
eed4e51f BP |
610 | ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector, |
611 | unsigned long nr_segs, unsigned long fast_segs, | |
612 | struct iovec *fast_pointer, | |
ac34ebb3 | 613 | struct iovec **ret_pointer) |
435f49a5 | 614 | { |
eed4e51f | 615 | unsigned long seg; |
435f49a5 | 616 | ssize_t ret; |
eed4e51f BP |
617 | struct iovec *iov = fast_pointer; |
618 | ||
435f49a5 LT |
619 | /* |
620 | * SuS says "The readv() function *may* fail if the iovcnt argument | |
621 | * was less than or equal to 0, or greater than {IOV_MAX}. Linux has | |
622 | * traditionally returned zero for zero segments, so... | |
623 | */ | |
eed4e51f BP |
624 | if (nr_segs == 0) { |
625 | ret = 0; | |
435f49a5 | 626 | goto out; |
eed4e51f BP |
627 | } |
628 | ||
435f49a5 LT |
629 | /* |
630 | * First get the "struct iovec" from user memory and | |
631 | * verify all the pointers | |
632 | */ | |
eed4e51f BP |
633 | if (nr_segs > UIO_MAXIOV) { |
634 | ret = -EINVAL; | |
435f49a5 | 635 | goto out; |
eed4e51f BP |
636 | } |
637 | if (nr_segs > fast_segs) { | |
435f49a5 | 638 | iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL); |
eed4e51f BP |
639 | if (iov == NULL) { |
640 | ret = -ENOMEM; | |
435f49a5 | 641 | goto out; |
eed4e51f | 642 | } |
435f49a5 | 643 | } |
eed4e51f BP |
644 | if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) { |
645 | ret = -EFAULT; | |
435f49a5 | 646 | goto out; |
eed4e51f BP |
647 | } |
648 | ||
435f49a5 | 649 | /* |
eed4e51f BP |
650 | * According to the Single Unix Specification we should return EINVAL |
651 | * if an element length is < 0 when cast to ssize_t or if the | |
652 | * total length would overflow the ssize_t return value of the | |
653 | * system call. | |
435f49a5 LT |
654 | * |
655 | * Linux caps all read/write calls to MAX_RW_COUNT, and avoids the | |
656 | * overflow case. | |
657 | */ | |
eed4e51f | 658 | ret = 0; |
435f49a5 LT |
659 | for (seg = 0; seg < nr_segs; seg++) { |
660 | void __user *buf = iov[seg].iov_base; | |
661 | ssize_t len = (ssize_t)iov[seg].iov_len; | |
eed4e51f BP |
662 | |
663 | /* see if we we're about to use an invalid len or if | |
664 | * it's about to overflow ssize_t */ | |
435f49a5 | 665 | if (len < 0) { |
eed4e51f | 666 | ret = -EINVAL; |
435f49a5 | 667 | goto out; |
eed4e51f | 668 | } |
ac34ebb3 | 669 | if (type >= 0 |
fcf63409 | 670 | && unlikely(!access_ok(vrfy_dir(type), buf, len))) { |
eed4e51f | 671 | ret = -EFAULT; |
435f49a5 LT |
672 | goto out; |
673 | } | |
674 | if (len > MAX_RW_COUNT - ret) { | |
675 | len = MAX_RW_COUNT - ret; | |
676 | iov[seg].iov_len = len; | |
eed4e51f | 677 | } |
eed4e51f | 678 | ret += len; |
435f49a5 | 679 | } |
eed4e51f BP |
680 | out: |
681 | *ret_pointer = iov; | |
682 | return ret; | |
683 | } | |
684 | ||
1da177e4 LT |
685 | static ssize_t do_readv_writev(int type, struct file *file, |
686 | const struct iovec __user * uvector, | |
687 | unsigned long nr_segs, loff_t *pos) | |
688 | { | |
1da177e4 LT |
689 | size_t tot_len; |
690 | struct iovec iovstack[UIO_FASTIOV]; | |
ee0b3e67 | 691 | struct iovec *iov = iovstack; |
1da177e4 | 692 | ssize_t ret; |
1da177e4 LT |
693 | io_fn_t fn; |
694 | iov_fn_t fnv; | |
695 | ||
eed4e51f BP |
696 | if (!file->f_op) { |
697 | ret = -EINVAL; | |
1da177e4 | 698 | goto out; |
1da177e4 | 699 | } |
1da177e4 | 700 | |
eed4e51f | 701 | ret = rw_copy_check_uvector(type, uvector, nr_segs, |
ac34ebb3 | 702 | ARRAY_SIZE(iovstack), iovstack, &iov); |
eed4e51f | 703 | if (ret <= 0) |
1da177e4 | 704 | goto out; |
1da177e4 | 705 | |
eed4e51f | 706 | tot_len = ret; |
1da177e4 | 707 | ret = rw_verify_area(type, file, pos, tot_len); |
e28cc715 | 708 | if (ret < 0) |
411b67b4 | 709 | goto out; |
1da177e4 LT |
710 | |
711 | fnv = NULL; | |
712 | if (type == READ) { | |
713 | fn = file->f_op->read; | |
ee0b3e67 | 714 | fnv = file->f_op->aio_read; |
1da177e4 LT |
715 | } else { |
716 | fn = (io_fn_t)file->f_op->write; | |
ee0b3e67 | 717 | fnv = file->f_op->aio_write; |
1da177e4 LT |
718 | } |
719 | ||
ee0b3e67 BP |
720 | if (fnv) |
721 | ret = do_sync_readv_writev(file, iov, nr_segs, tot_len, | |
722 | pos, fnv); | |
723 | else | |
724 | ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn); | |
1da177e4 | 725 | |
1da177e4 LT |
726 | out: |
727 | if (iov != iovstack) | |
728 | kfree(iov); | |
0eeca283 RL |
729 | if ((ret + (type == READ)) > 0) { |
730 | if (type == READ) | |
2a12a9d7 | 731 | fsnotify_access(file); |
0eeca283 | 732 | else |
2a12a9d7 | 733 | fsnotify_modify(file); |
0eeca283 | 734 | } |
1da177e4 | 735 | return ret; |
1da177e4 LT |
736 | } |
737 | ||
738 | ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, | |
739 | unsigned long vlen, loff_t *pos) | |
740 | { | |
741 | if (!(file->f_mode & FMODE_READ)) | |
742 | return -EBADF; | |
ee0b3e67 | 743 | if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read)) |
1da177e4 LT |
744 | return -EINVAL; |
745 | ||
746 | return do_readv_writev(READ, file, vec, vlen, pos); | |
747 | } | |
748 | ||
749 | EXPORT_SYMBOL(vfs_readv); | |
750 | ||
751 | ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, | |
752 | unsigned long vlen, loff_t *pos) | |
753 | { | |
754 | if (!(file->f_mode & FMODE_WRITE)) | |
755 | return -EBADF; | |
ee0b3e67 | 756 | if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write)) |
1da177e4 LT |
757 | return -EINVAL; |
758 | ||
759 | return do_readv_writev(WRITE, file, vec, vlen, pos); | |
760 | } | |
761 | ||
762 | EXPORT_SYMBOL(vfs_writev); | |
763 | ||
3cdad428 HC |
764 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, |
765 | unsigned long, vlen) | |
1da177e4 | 766 | { |
2903ff01 | 767 | struct fd f = fdget(fd); |
1da177e4 | 768 | ssize_t ret = -EBADF; |
1da177e4 | 769 | |
2903ff01 AV |
770 | if (f.file) { |
771 | loff_t pos = file_pos_read(f.file); | |
772 | ret = vfs_readv(f.file, vec, vlen, &pos); | |
773 | file_pos_write(f.file, pos); | |
774 | fdput(f); | |
1da177e4 LT |
775 | } |
776 | ||
777 | if (ret > 0) | |
4b98d11b AD |
778 | add_rchar(current, ret); |
779 | inc_syscr(current); | |
1da177e4 LT |
780 | return ret; |
781 | } | |
782 | ||
3cdad428 HC |
783 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, |
784 | unsigned long, vlen) | |
1da177e4 | 785 | { |
2903ff01 | 786 | struct fd f = fdget(fd); |
1da177e4 | 787 | ssize_t ret = -EBADF; |
1da177e4 | 788 | |
2903ff01 AV |
789 | if (f.file) { |
790 | loff_t pos = file_pos_read(f.file); | |
791 | ret = vfs_writev(f.file, vec, vlen, &pos); | |
792 | file_pos_write(f.file, pos); | |
793 | fdput(f); | |
1da177e4 LT |
794 | } |
795 | ||
796 | if (ret > 0) | |
4b98d11b AD |
797 | add_wchar(current, ret); |
798 | inc_syscw(current); | |
1da177e4 LT |
799 | return ret; |
800 | } | |
801 | ||
601cc11d LT |
802 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) |
803 | { | |
804 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) | |
805 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; | |
806 | } | |
807 | ||
f3554f4b | 808 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, |
601cc11d | 809 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
f3554f4b | 810 | { |
601cc11d | 811 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
2903ff01 | 812 | struct fd f; |
f3554f4b | 813 | ssize_t ret = -EBADF; |
f3554f4b GH |
814 | |
815 | if (pos < 0) | |
816 | return -EINVAL; | |
817 | ||
2903ff01 AV |
818 | f = fdget(fd); |
819 | if (f.file) { | |
f3554f4b | 820 | ret = -ESPIPE; |
2903ff01 AV |
821 | if (f.file->f_mode & FMODE_PREAD) |
822 | ret = vfs_readv(f.file, vec, vlen, &pos); | |
823 | fdput(f); | |
f3554f4b GH |
824 | } |
825 | ||
826 | if (ret > 0) | |
827 | add_rchar(current, ret); | |
828 | inc_syscr(current); | |
829 | return ret; | |
830 | } | |
831 | ||
832 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, | |
601cc11d | 833 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
f3554f4b | 834 | { |
601cc11d | 835 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
2903ff01 | 836 | struct fd f; |
f3554f4b | 837 | ssize_t ret = -EBADF; |
f3554f4b GH |
838 | |
839 | if (pos < 0) | |
840 | return -EINVAL; | |
841 | ||
2903ff01 AV |
842 | f = fdget(fd); |
843 | if (f.file) { | |
f3554f4b | 844 | ret = -ESPIPE; |
2903ff01 AV |
845 | if (f.file->f_mode & FMODE_PWRITE) |
846 | ret = vfs_writev(f.file, vec, vlen, &pos); | |
847 | fdput(f); | |
f3554f4b GH |
848 | } |
849 | ||
850 | if (ret > 0) | |
851 | add_wchar(current, ret); | |
852 | inc_syscw(current); | |
853 | return ret; | |
854 | } | |
855 | ||
8f9c0119 CM |
856 | ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, size_t count, |
857 | loff_t max) | |
1da177e4 | 858 | { |
2903ff01 AV |
859 | struct fd in, out; |
860 | struct inode *in_inode, *out_inode; | |
1da177e4 LT |
861 | loff_t pos; |
862 | ssize_t retval; | |
2903ff01 | 863 | int fl; |
1da177e4 LT |
864 | |
865 | /* | |
866 | * Get input file, and verify that it is ok.. | |
867 | */ | |
868 | retval = -EBADF; | |
2903ff01 AV |
869 | in = fdget(in_fd); |
870 | if (!in.file) | |
1da177e4 | 871 | goto out; |
2903ff01 | 872 | if (!(in.file->f_mode & FMODE_READ)) |
1da177e4 | 873 | goto fput_in; |
1da177e4 LT |
874 | retval = -ESPIPE; |
875 | if (!ppos) | |
2903ff01 | 876 | ppos = &in.file->f_pos; |
1da177e4 | 877 | else |
2903ff01 | 878 | if (!(in.file->f_mode & FMODE_PREAD)) |
1da177e4 | 879 | goto fput_in; |
2903ff01 | 880 | retval = rw_verify_area(READ, in.file, ppos, count); |
e28cc715 | 881 | if (retval < 0) |
1da177e4 | 882 | goto fput_in; |
e28cc715 | 883 | count = retval; |
1da177e4 | 884 | |
1da177e4 LT |
885 | /* |
886 | * Get output file, and verify that it is ok.. | |
887 | */ | |
888 | retval = -EBADF; | |
2903ff01 AV |
889 | out = fdget(out_fd); |
890 | if (!out.file) | |
1da177e4 | 891 | goto fput_in; |
2903ff01 | 892 | if (!(out.file->f_mode & FMODE_WRITE)) |
1da177e4 LT |
893 | goto fput_out; |
894 | retval = -EINVAL; | |
496ad9aa AV |
895 | in_inode = file_inode(in.file); |
896 | out_inode = file_inode(out.file); | |
2903ff01 | 897 | retval = rw_verify_area(WRITE, out.file, &out.file->f_pos, count); |
e28cc715 | 898 | if (retval < 0) |
1da177e4 | 899 | goto fput_out; |
e28cc715 | 900 | count = retval; |
1da177e4 | 901 | |
1da177e4 LT |
902 | if (!max) |
903 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); | |
904 | ||
905 | pos = *ppos; | |
1da177e4 LT |
906 | if (unlikely(pos + count > max)) { |
907 | retval = -EOVERFLOW; | |
908 | if (pos >= max) | |
909 | goto fput_out; | |
910 | count = max - pos; | |
911 | } | |
912 | ||
d96e6e71 | 913 | fl = 0; |
534f2aaa | 914 | #if 0 |
d96e6e71 JA |
915 | /* |
916 | * We need to debate whether we can enable this or not. The | |
917 | * man page documents EAGAIN return for the output at least, | |
918 | * and the application is arguably buggy if it doesn't expect | |
919 | * EAGAIN on a non-blocking file descriptor. | |
920 | */ | |
2903ff01 | 921 | if (in.file->f_flags & O_NONBLOCK) |
d96e6e71 | 922 | fl = SPLICE_F_NONBLOCK; |
534f2aaa | 923 | #endif |
2903ff01 | 924 | retval = do_splice_direct(in.file, ppos, out.file, count, fl); |
1da177e4 LT |
925 | |
926 | if (retval > 0) { | |
4b98d11b AD |
927 | add_rchar(current, retval); |
928 | add_wchar(current, retval); | |
a68c2f12 SW |
929 | fsnotify_access(in.file); |
930 | fsnotify_modify(out.file); | |
1da177e4 | 931 | } |
1da177e4 | 932 | |
4b98d11b AD |
933 | inc_syscr(current); |
934 | inc_syscw(current); | |
1da177e4 LT |
935 | if (*ppos > max) |
936 | retval = -EOVERFLOW; | |
937 | ||
938 | fput_out: | |
2903ff01 | 939 | fdput(out); |
1da177e4 | 940 | fput_in: |
2903ff01 | 941 | fdput(in); |
1da177e4 LT |
942 | out: |
943 | return retval; | |
944 | } | |
945 | ||
002c8976 | 946 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) |
1da177e4 LT |
947 | { |
948 | loff_t pos; | |
949 | off_t off; | |
950 | ssize_t ret; | |
951 | ||
952 | if (offset) { | |
953 | if (unlikely(get_user(off, offset))) | |
954 | return -EFAULT; | |
955 | pos = off; | |
956 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); | |
957 | if (unlikely(put_user(pos, offset))) | |
958 | return -EFAULT; | |
959 | return ret; | |
960 | } | |
961 | ||
962 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
963 | } | |
964 | ||
002c8976 | 965 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) |
1da177e4 LT |
966 | { |
967 | loff_t pos; | |
968 | ssize_t ret; | |
969 | ||
970 | if (offset) { | |
971 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) | |
972 | return -EFAULT; | |
973 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); | |
974 | if (unlikely(put_user(pos, offset))) | |
975 | return -EFAULT; | |
976 | return ret; | |
977 | } | |
978 | ||
979 | return do_sendfile(out_fd, in_fd, NULL, count, 0); | |
980 | } |