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