| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * linux/fs/read_write.c |
| 4 | * |
| 5 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 6 | */ |
| 7 | |
| 8 | #include <linux/slab.h> |
| 9 | #include <linux/stat.h> |
| 10 | #include <linux/sched/xacct.h> |
| 11 | #include <linux/fcntl.h> |
| 12 | #include <linux/file.h> |
| 13 | #include <linux/uio.h> |
| 14 | #include <linux/fsnotify.h> |
| 15 | #include <linux/security.h> |
| 16 | #include <linux/export.h> |
| 17 | #include <linux/syscalls.h> |
| 18 | #include <linux/pagemap.h> |
| 19 | #include <linux/splice.h> |
| 20 | #include <linux/compat.h> |
| 21 | #include <linux/mount.h> |
| 22 | #include <linux/fs.h> |
| 23 | #include "internal.h" |
| 24 | |
| 25 | #include <linux/uaccess.h> |
| 26 | #include <asm/unistd.h> |
| 27 | |
| 28 | const struct file_operations generic_ro_fops = { |
| 29 | .llseek = generic_file_llseek, |
| 30 | .read_iter = generic_file_read_iter, |
| 31 | .mmap = generic_file_readonly_mmap, |
| 32 | .splice_read = generic_file_splice_read, |
| 33 | }; |
| 34 | |
| 35 | EXPORT_SYMBOL(generic_ro_fops); |
| 36 | |
| 37 | static inline bool unsigned_offsets(struct file *file) |
| 38 | { |
| 39 | return file->f_mode & FMODE_UNSIGNED_OFFSET; |
| 40 | } |
| 41 | |
| 42 | /** |
| 43 | * vfs_setpos - update the file offset for lseek |
| 44 | * @file: file structure in question |
| 45 | * @offset: file offset to seek to |
| 46 | * @maxsize: maximum file size |
| 47 | * |
| 48 | * This is a low-level filesystem helper for updating the file offset to |
| 49 | * the value specified by @offset if the given offset is valid and it is |
| 50 | * not equal to the current file offset. |
| 51 | * |
| 52 | * Return the specified offset on success and -EINVAL on invalid offset. |
| 53 | */ |
| 54 | loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize) |
| 55 | { |
| 56 | if (offset < 0 && !unsigned_offsets(file)) |
| 57 | return -EINVAL; |
| 58 | if (offset > maxsize) |
| 59 | return -EINVAL; |
| 60 | |
| 61 | if (offset != file->f_pos) { |
| 62 | file->f_pos = offset; |
| 63 | file->f_version = 0; |
| 64 | } |
| 65 | return offset; |
| 66 | } |
| 67 | EXPORT_SYMBOL(vfs_setpos); |
| 68 | |
| 69 | /** |
| 70 | * generic_file_llseek_size - generic llseek implementation for regular files |
| 71 | * @file: file structure to seek on |
| 72 | * @offset: file offset to seek to |
| 73 | * @whence: type of seek |
| 74 | * @size: max size of this file in file system |
| 75 | * @eof: offset used for SEEK_END position |
| 76 | * |
| 77 | * This is a variant of generic_file_llseek that allows passing in a custom |
| 78 | * maximum file size and a custom EOF position, for e.g. hashed directories |
| 79 | * |
| 80 | * Synchronization: |
| 81 | * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms) |
| 82 | * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes. |
| 83 | * read/writes behave like SEEK_SET against seeks. |
| 84 | */ |
| 85 | loff_t |
| 86 | generic_file_llseek_size(struct file *file, loff_t offset, int whence, |
| 87 | loff_t maxsize, loff_t eof) |
| 88 | { |
| 89 | switch (whence) { |
| 90 | case SEEK_END: |
| 91 | offset += eof; |
| 92 | break; |
| 93 | case SEEK_CUR: |
| 94 | /* |
| 95 | * Here we special-case the lseek(fd, 0, SEEK_CUR) |
| 96 | * position-querying operation. Avoid rewriting the "same" |
| 97 | * f_pos value back to the file because a concurrent read(), |
| 98 | * write() or lseek() might have altered it |
| 99 | */ |
| 100 | if (offset == 0) |
| 101 | return file->f_pos; |
| 102 | /* |
| 103 | * f_lock protects against read/modify/write race with other |
| 104 | * SEEK_CURs. Note that parallel writes and reads behave |
| 105 | * like SEEK_SET. |
| 106 | */ |
| 107 | spin_lock(&file->f_lock); |
| 108 | offset = vfs_setpos(file, file->f_pos + offset, maxsize); |
| 109 | spin_unlock(&file->f_lock); |
| 110 | return offset; |
| 111 | case SEEK_DATA: |
| 112 | /* |
| 113 | * In the generic case the entire file is data, so as long as |
| 114 | * offset isn't at the end of the file then the offset is data. |
| 115 | */ |
| 116 | if ((unsigned long long)offset >= eof) |
| 117 | return -ENXIO; |
| 118 | break; |
| 119 | case SEEK_HOLE: |
| 120 | /* |
| 121 | * There is a virtual hole at the end of the file, so as long as |
| 122 | * offset isn't i_size or larger, return i_size. |
| 123 | */ |
| 124 | if ((unsigned long long)offset >= eof) |
| 125 | return -ENXIO; |
| 126 | offset = eof; |
| 127 | break; |
| 128 | } |
| 129 | |
| 130 | return vfs_setpos(file, offset, maxsize); |
| 131 | } |
| 132 | EXPORT_SYMBOL(generic_file_llseek_size); |
| 133 | |
| 134 | /** |
| 135 | * generic_file_llseek - generic llseek implementation for regular files |
| 136 | * @file: file structure to seek on |
| 137 | * @offset: file offset to seek to |
| 138 | * @whence: type of seek |
| 139 | * |
| 140 | * This is a generic implemenation of ->llseek useable for all normal local |
| 141 | * filesystems. It just updates the file offset to the value specified by |
| 142 | * @offset and @whence. |
| 143 | */ |
| 144 | loff_t generic_file_llseek(struct file *file, loff_t offset, int whence) |
| 145 | { |
| 146 | struct inode *inode = file->f_mapping->host; |
| 147 | |
| 148 | return generic_file_llseek_size(file, offset, whence, |
| 149 | inode->i_sb->s_maxbytes, |
| 150 | i_size_read(inode)); |
| 151 | } |
| 152 | EXPORT_SYMBOL(generic_file_llseek); |
| 153 | |
| 154 | /** |
| 155 | * fixed_size_llseek - llseek implementation for fixed-sized devices |
| 156 | * @file: file structure to seek on |
| 157 | * @offset: file offset to seek to |
| 158 | * @whence: type of seek |
| 159 | * @size: size of the file |
| 160 | * |
| 161 | */ |
| 162 | loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size) |
| 163 | { |
| 164 | switch (whence) { |
| 165 | case SEEK_SET: case SEEK_CUR: case SEEK_END: |
| 166 | return generic_file_llseek_size(file, offset, whence, |
| 167 | size, size); |
| 168 | default: |
| 169 | return -EINVAL; |
| 170 | } |
| 171 | } |
| 172 | EXPORT_SYMBOL(fixed_size_llseek); |
| 173 | |
| 174 | /** |
| 175 | * no_seek_end_llseek - llseek implementation for fixed-sized devices |
| 176 | * @file: file structure to seek on |
| 177 | * @offset: file offset to seek to |
| 178 | * @whence: type of seek |
| 179 | * |
| 180 | */ |
| 181 | loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence) |
| 182 | { |
| 183 | switch (whence) { |
| 184 | case SEEK_SET: case SEEK_CUR: |
| 185 | return generic_file_llseek_size(file, offset, whence, |
| 186 | OFFSET_MAX, 0); |
| 187 | default: |
| 188 | return -EINVAL; |
| 189 | } |
| 190 | } |
| 191 | EXPORT_SYMBOL(no_seek_end_llseek); |
| 192 | |
| 193 | /** |
| 194 | * no_seek_end_llseek_size - llseek implementation for fixed-sized devices |
| 195 | * @file: file structure to seek on |
| 196 | * @offset: file offset to seek to |
| 197 | * @whence: type of seek |
| 198 | * @size: maximal offset allowed |
| 199 | * |
| 200 | */ |
| 201 | loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size) |
| 202 | { |
| 203 | switch (whence) { |
| 204 | case SEEK_SET: case SEEK_CUR: |
| 205 | return generic_file_llseek_size(file, offset, whence, |
| 206 | size, 0); |
| 207 | default: |
| 208 | return -EINVAL; |
| 209 | } |
| 210 | } |
| 211 | EXPORT_SYMBOL(no_seek_end_llseek_size); |
| 212 | |
| 213 | /** |
| 214 | * noop_llseek - No Operation Performed llseek implementation |
| 215 | * @file: file structure to seek on |
| 216 | * @offset: file offset to seek to |
| 217 | * @whence: type of seek |
| 218 | * |
| 219 | * This is an implementation of ->llseek useable for the rare special case when |
| 220 | * userspace expects the seek to succeed but the (device) file is actually not |
| 221 | * able to perform the seek. In this case you use noop_llseek() instead of |
| 222 | * falling back to the default implementation of ->llseek. |
| 223 | */ |
| 224 | loff_t noop_llseek(struct file *file, loff_t offset, int whence) |
| 225 | { |
| 226 | return file->f_pos; |
| 227 | } |
| 228 | EXPORT_SYMBOL(noop_llseek); |
| 229 | |
| 230 | loff_t default_llseek(struct file *file, loff_t offset, int whence) |
| 231 | { |
| 232 | struct inode *inode = file_inode(file); |
| 233 | loff_t retval; |
| 234 | |
| 235 | inode_lock(inode); |
| 236 | switch (whence) { |
| 237 | case SEEK_END: |
| 238 | offset += i_size_read(inode); |
| 239 | break; |
| 240 | case SEEK_CUR: |
| 241 | if (offset == 0) { |
| 242 | retval = file->f_pos; |
| 243 | goto out; |
| 244 | } |
| 245 | offset += file->f_pos; |
| 246 | break; |
| 247 | case SEEK_DATA: |
| 248 | /* |
| 249 | * In the generic case the entire file is data, so as |
| 250 | * long as offset isn't at the end of the file then the |
| 251 | * offset is data. |
| 252 | */ |
| 253 | if (offset >= inode->i_size) { |
| 254 | retval = -ENXIO; |
| 255 | goto out; |
| 256 | } |
| 257 | break; |
| 258 | case SEEK_HOLE: |
| 259 | /* |
| 260 | * There is a virtual hole at the end of the file, so |
| 261 | * as long as offset isn't i_size or larger, return |
| 262 | * i_size. |
| 263 | */ |
| 264 | if (offset >= inode->i_size) { |
| 265 | retval = -ENXIO; |
| 266 | goto out; |
| 267 | } |
| 268 | offset = inode->i_size; |
| 269 | break; |
| 270 | } |
| 271 | retval = -EINVAL; |
| 272 | if (offset >= 0 || unsigned_offsets(file)) { |
| 273 | if (offset != file->f_pos) { |
| 274 | file->f_pos = offset; |
| 275 | file->f_version = 0; |
| 276 | } |
| 277 | retval = offset; |
| 278 | } |
| 279 | out: |
| 280 | inode_unlock(inode); |
| 281 | return retval; |
| 282 | } |
| 283 | EXPORT_SYMBOL(default_llseek); |
| 284 | |
| 285 | loff_t vfs_llseek(struct file *file, loff_t offset, int whence) |
| 286 | { |
| 287 | if (!(file->f_mode & FMODE_LSEEK)) |
| 288 | return -ESPIPE; |
| 289 | return file->f_op->llseek(file, offset, whence); |
| 290 | } |
| 291 | EXPORT_SYMBOL(vfs_llseek); |
| 292 | |
| 293 | static off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence) |
| 294 | { |
| 295 | off_t retval; |
| 296 | struct fd f = fdget_pos(fd); |
| 297 | if (!f.file) |
| 298 | return -EBADF; |
| 299 | |
| 300 | retval = -EINVAL; |
| 301 | if (whence <= SEEK_MAX) { |
| 302 | loff_t res = vfs_llseek(f.file, offset, whence); |
| 303 | retval = res; |
| 304 | if (res != (loff_t)retval) |
| 305 | retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */ |
| 306 | } |
| 307 | fdput_pos(f); |
| 308 | return retval; |
| 309 | } |
| 310 | |
| 311 | SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence) |
| 312 | { |
| 313 | return ksys_lseek(fd, offset, whence); |
| 314 | } |
| 315 | |
| 316 | #ifdef CONFIG_COMPAT |
| 317 | COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence) |
| 318 | { |
| 319 | return ksys_lseek(fd, offset, whence); |
| 320 | } |
| 321 | #endif |
| 322 | |
| 323 | #if !defined(CONFIG_64BIT) || defined(CONFIG_COMPAT) || \ |
| 324 | defined(__ARCH_WANT_SYS_LLSEEK) |
| 325 | SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high, |
| 326 | unsigned long, offset_low, loff_t __user *, result, |
| 327 | unsigned int, whence) |
| 328 | { |
| 329 | int retval; |
| 330 | struct fd f = fdget_pos(fd); |
| 331 | loff_t offset; |
| 332 | |
| 333 | if (!f.file) |
| 334 | return -EBADF; |
| 335 | |
| 336 | retval = -EINVAL; |
| 337 | if (whence > SEEK_MAX) |
| 338 | goto out_putf; |
| 339 | |
| 340 | offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low, |
| 341 | whence); |
| 342 | |
| 343 | retval = (int)offset; |
| 344 | if (offset >= 0) { |
| 345 | retval = -EFAULT; |
| 346 | if (!copy_to_user(result, &offset, sizeof(offset))) |
| 347 | retval = 0; |
| 348 | } |
| 349 | out_putf: |
| 350 | fdput_pos(f); |
| 351 | return retval; |
| 352 | } |
| 353 | #endif |
| 354 | |
| 355 | int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count) |
| 356 | { |
| 357 | if (unlikely((ssize_t) count < 0)) |
| 358 | return -EINVAL; |
| 359 | |
| 360 | if (ppos) { |
| 361 | loff_t pos = *ppos; |
| 362 | |
| 363 | if (unlikely(pos < 0)) { |
| 364 | if (!unsigned_offsets(file)) |
| 365 | return -EINVAL; |
| 366 | if (count >= -pos) /* both values are in 0..LLONG_MAX */ |
| 367 | return -EOVERFLOW; |
| 368 | } else if (unlikely((loff_t) (pos + count) < 0)) { |
| 369 | if (!unsigned_offsets(file)) |
| 370 | return -EINVAL; |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | return security_file_permission(file, |
| 375 | read_write == READ ? MAY_READ : MAY_WRITE); |
| 376 | } |
| 377 | EXPORT_SYMBOL(rw_verify_area); |
| 378 | |
| 379 | static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos) |
| 380 | { |
| 381 | struct kiocb kiocb; |
| 382 | struct iov_iter iter; |
| 383 | ssize_t ret; |
| 384 | |
| 385 | init_sync_kiocb(&kiocb, filp); |
| 386 | kiocb.ki_pos = (ppos ? *ppos : 0); |
| 387 | iov_iter_ubuf(&iter, ITER_DEST, buf, len); |
| 388 | |
| 389 | ret = call_read_iter(filp, &kiocb, &iter); |
| 390 | BUG_ON(ret == -EIOCBQUEUED); |
| 391 | if (ppos) |
| 392 | *ppos = kiocb.ki_pos; |
| 393 | return ret; |
| 394 | } |
| 395 | |
| 396 | static int warn_unsupported(struct file *file, const char *op) |
| 397 | { |
| 398 | pr_warn_ratelimited( |
| 399 | "kernel %s not supported for file %pD4 (pid: %d comm: %.20s)\n", |
| 400 | op, file, current->pid, current->comm); |
| 401 | return -EINVAL; |
| 402 | } |
| 403 | |
| 404 | ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) |
| 405 | { |
| 406 | struct kvec iov = { |
| 407 | .iov_base = buf, |
| 408 | .iov_len = min_t(size_t, count, MAX_RW_COUNT), |
| 409 | }; |
| 410 | struct kiocb kiocb; |
| 411 | struct iov_iter iter; |
| 412 | ssize_t ret; |
| 413 | |
| 414 | if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ))) |
| 415 | return -EINVAL; |
| 416 | if (!(file->f_mode & FMODE_CAN_READ)) |
| 417 | return -EINVAL; |
| 418 | /* |
| 419 | * Also fail if ->read_iter and ->read are both wired up as that |
| 420 | * implies very convoluted semantics. |
| 421 | */ |
| 422 | if (unlikely(!file->f_op->read_iter || file->f_op->read)) |
| 423 | return warn_unsupported(file, "read"); |
| 424 | |
| 425 | init_sync_kiocb(&kiocb, file); |
| 426 | kiocb.ki_pos = pos ? *pos : 0; |
| 427 | iov_iter_kvec(&iter, ITER_DEST, &iov, 1, iov.iov_len); |
| 428 | ret = file->f_op->read_iter(&kiocb, &iter); |
| 429 | if (ret > 0) { |
| 430 | if (pos) |
| 431 | *pos = kiocb.ki_pos; |
| 432 | fsnotify_access(file); |
| 433 | add_rchar(current, ret); |
| 434 | } |
| 435 | inc_syscr(current); |
| 436 | return ret; |
| 437 | } |
| 438 | |
| 439 | ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) |
| 440 | { |
| 441 | ssize_t ret; |
| 442 | |
| 443 | ret = rw_verify_area(READ, file, pos, count); |
| 444 | if (ret) |
| 445 | return ret; |
| 446 | return __kernel_read(file, buf, count, pos); |
| 447 | } |
| 448 | EXPORT_SYMBOL(kernel_read); |
| 449 | |
| 450 | ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos) |
| 451 | { |
| 452 | ssize_t ret; |
| 453 | |
| 454 | if (!(file->f_mode & FMODE_READ)) |
| 455 | return -EBADF; |
| 456 | if (!(file->f_mode & FMODE_CAN_READ)) |
| 457 | return -EINVAL; |
| 458 | if (unlikely(!access_ok(buf, count))) |
| 459 | return -EFAULT; |
| 460 | |
| 461 | ret = rw_verify_area(READ, file, pos, count); |
| 462 | if (ret) |
| 463 | return ret; |
| 464 | if (count > MAX_RW_COUNT) |
| 465 | count = MAX_RW_COUNT; |
| 466 | |
| 467 | if (file->f_op->read) |
| 468 | ret = file->f_op->read(file, buf, count, pos); |
| 469 | else if (file->f_op->read_iter) |
| 470 | ret = new_sync_read(file, buf, count, pos); |
| 471 | else |
| 472 | ret = -EINVAL; |
| 473 | if (ret > 0) { |
| 474 | fsnotify_access(file); |
| 475 | add_rchar(current, ret); |
| 476 | } |
| 477 | inc_syscr(current); |
| 478 | return ret; |
| 479 | } |
| 480 | |
| 481 | static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos) |
| 482 | { |
| 483 | struct kiocb kiocb; |
| 484 | struct iov_iter iter; |
| 485 | ssize_t ret; |
| 486 | |
| 487 | init_sync_kiocb(&kiocb, filp); |
| 488 | kiocb.ki_pos = (ppos ? *ppos : 0); |
| 489 | iov_iter_ubuf(&iter, ITER_SOURCE, (void __user *)buf, len); |
| 490 | |
| 491 | ret = call_write_iter(filp, &kiocb, &iter); |
| 492 | BUG_ON(ret == -EIOCBQUEUED); |
| 493 | if (ret > 0 && ppos) |
| 494 | *ppos = kiocb.ki_pos; |
| 495 | return ret; |
| 496 | } |
| 497 | |
| 498 | /* caller is responsible for file_start_write/file_end_write */ |
| 499 | ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos) |
| 500 | { |
| 501 | struct kiocb kiocb; |
| 502 | ssize_t ret; |
| 503 | |
| 504 | if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE))) |
| 505 | return -EBADF; |
| 506 | if (!(file->f_mode & FMODE_CAN_WRITE)) |
| 507 | return -EINVAL; |
| 508 | /* |
| 509 | * Also fail if ->write_iter and ->write are both wired up as that |
| 510 | * implies very convoluted semantics. |
| 511 | */ |
| 512 | if (unlikely(!file->f_op->write_iter || file->f_op->write)) |
| 513 | return warn_unsupported(file, "write"); |
| 514 | |
| 515 | init_sync_kiocb(&kiocb, file); |
| 516 | kiocb.ki_pos = pos ? *pos : 0; |
| 517 | ret = file->f_op->write_iter(&kiocb, from); |
| 518 | if (ret > 0) { |
| 519 | if (pos) |
| 520 | *pos = kiocb.ki_pos; |
| 521 | fsnotify_modify(file); |
| 522 | add_wchar(current, ret); |
| 523 | } |
| 524 | inc_syscw(current); |
| 525 | return ret; |
| 526 | } |
| 527 | |
| 528 | /* caller is responsible for file_start_write/file_end_write */ |
| 529 | ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos) |
| 530 | { |
| 531 | struct kvec iov = { |
| 532 | .iov_base = (void *)buf, |
| 533 | .iov_len = min_t(size_t, count, MAX_RW_COUNT), |
| 534 | }; |
| 535 | struct iov_iter iter; |
| 536 | iov_iter_kvec(&iter, ITER_SOURCE, &iov, 1, iov.iov_len); |
| 537 | return __kernel_write_iter(file, &iter, pos); |
| 538 | } |
| 539 | /* |
| 540 | * This "EXPORT_SYMBOL_GPL()" is more of a "EXPORT_SYMBOL_DONTUSE()", |
| 541 | * but autofs is one of the few internal kernel users that actually |
| 542 | * wants this _and_ can be built as a module. So we need to export |
| 543 | * this symbol for autofs, even though it really isn't appropriate |
| 544 | * for any other kernel modules. |
| 545 | */ |
| 546 | EXPORT_SYMBOL_GPL(__kernel_write); |
| 547 | |
| 548 | ssize_t kernel_write(struct file *file, const void *buf, size_t count, |
| 549 | loff_t *pos) |
| 550 | { |
| 551 | ssize_t ret; |
| 552 | |
| 553 | ret = rw_verify_area(WRITE, file, pos, count); |
| 554 | if (ret) |
| 555 | return ret; |
| 556 | |
| 557 | file_start_write(file); |
| 558 | ret = __kernel_write(file, buf, count, pos); |
| 559 | file_end_write(file); |
| 560 | return ret; |
| 561 | } |
| 562 | EXPORT_SYMBOL(kernel_write); |
| 563 | |
| 564 | ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos) |
| 565 | { |
| 566 | ssize_t ret; |
| 567 | |
| 568 | if (!(file->f_mode & FMODE_WRITE)) |
| 569 | return -EBADF; |
| 570 | if (!(file->f_mode & FMODE_CAN_WRITE)) |
| 571 | return -EINVAL; |
| 572 | if (unlikely(!access_ok(buf, count))) |
| 573 | return -EFAULT; |
| 574 | |
| 575 | ret = rw_verify_area(WRITE, file, pos, count); |
| 576 | if (ret) |
| 577 | return ret; |
| 578 | if (count > MAX_RW_COUNT) |
| 579 | count = MAX_RW_COUNT; |
| 580 | file_start_write(file); |
| 581 | if (file->f_op->write) |
| 582 | ret = file->f_op->write(file, buf, count, pos); |
| 583 | else if (file->f_op->write_iter) |
| 584 | ret = new_sync_write(file, buf, count, pos); |
| 585 | else |
| 586 | ret = -EINVAL; |
| 587 | if (ret > 0) { |
| 588 | fsnotify_modify(file); |
| 589 | add_wchar(current, ret); |
| 590 | } |
| 591 | inc_syscw(current); |
| 592 | file_end_write(file); |
| 593 | return ret; |
| 594 | } |
| 595 | |
| 596 | /* file_ppos returns &file->f_pos or NULL if file is stream */ |
| 597 | static inline loff_t *file_ppos(struct file *file) |
| 598 | { |
| 599 | return file->f_mode & FMODE_STREAM ? NULL : &file->f_pos; |
| 600 | } |
| 601 | |
| 602 | ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count) |
| 603 | { |
| 604 | struct fd f = fdget_pos(fd); |
| 605 | ssize_t ret = -EBADF; |
| 606 | |
| 607 | if (f.file) { |
| 608 | loff_t pos, *ppos = file_ppos(f.file); |
| 609 | if (ppos) { |
| 610 | pos = *ppos; |
| 611 | ppos = &pos; |
| 612 | } |
| 613 | ret = vfs_read(f.file, buf, count, ppos); |
| 614 | if (ret >= 0 && ppos) |
| 615 | f.file->f_pos = pos; |
| 616 | fdput_pos(f); |
| 617 | } |
| 618 | return ret; |
| 619 | } |
| 620 | |
| 621 | SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count) |
| 622 | { |
| 623 | return ksys_read(fd, buf, count); |
| 624 | } |
| 625 | |
| 626 | ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count) |
| 627 | { |
| 628 | struct fd f = fdget_pos(fd); |
| 629 | ssize_t ret = -EBADF; |
| 630 | |
| 631 | if (f.file) { |
| 632 | loff_t pos, *ppos = file_ppos(f.file); |
| 633 | if (ppos) { |
| 634 | pos = *ppos; |
| 635 | ppos = &pos; |
| 636 | } |
| 637 | ret = vfs_write(f.file, buf, count, ppos); |
| 638 | if (ret >= 0 && ppos) |
| 639 | f.file->f_pos = pos; |
| 640 | fdput_pos(f); |
| 641 | } |
| 642 | |
| 643 | return ret; |
| 644 | } |
| 645 | |
| 646 | SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf, |
| 647 | size_t, count) |
| 648 | { |
| 649 | return ksys_write(fd, buf, count); |
| 650 | } |
| 651 | |
| 652 | ssize_t ksys_pread64(unsigned int fd, char __user *buf, size_t count, |
| 653 | loff_t pos) |
| 654 | { |
| 655 | struct fd f; |
| 656 | ssize_t ret = -EBADF; |
| 657 | |
| 658 | if (pos < 0) |
| 659 | return -EINVAL; |
| 660 | |
| 661 | f = fdget(fd); |
| 662 | if (f.file) { |
| 663 | ret = -ESPIPE; |
| 664 | if (f.file->f_mode & FMODE_PREAD) |
| 665 | ret = vfs_read(f.file, buf, count, &pos); |
| 666 | fdput(f); |
| 667 | } |
| 668 | |
| 669 | return ret; |
| 670 | } |
| 671 | |
| 672 | SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf, |
| 673 | size_t, count, loff_t, pos) |
| 674 | { |
| 675 | return ksys_pread64(fd, buf, count, pos); |
| 676 | } |
| 677 | |
| 678 | #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PREAD64) |
| 679 | COMPAT_SYSCALL_DEFINE5(pread64, unsigned int, fd, char __user *, buf, |
| 680 | size_t, count, compat_arg_u64_dual(pos)) |
| 681 | { |
| 682 | return ksys_pread64(fd, buf, count, compat_arg_u64_glue(pos)); |
| 683 | } |
| 684 | #endif |
| 685 | |
| 686 | ssize_t ksys_pwrite64(unsigned int fd, const char __user *buf, |
| 687 | size_t count, loff_t pos) |
| 688 | { |
| 689 | struct fd f; |
| 690 | ssize_t ret = -EBADF; |
| 691 | |
| 692 | if (pos < 0) |
| 693 | return -EINVAL; |
| 694 | |
| 695 | f = fdget(fd); |
| 696 | if (f.file) { |
| 697 | ret = -ESPIPE; |
| 698 | if (f.file->f_mode & FMODE_PWRITE) |
| 699 | ret = vfs_write(f.file, buf, count, &pos); |
| 700 | fdput(f); |
| 701 | } |
| 702 | |
| 703 | return ret; |
| 704 | } |
| 705 | |
| 706 | SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf, |
| 707 | size_t, count, loff_t, pos) |
| 708 | { |
| 709 | return ksys_pwrite64(fd, buf, count, pos); |
| 710 | } |
| 711 | |
| 712 | #if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PWRITE64) |
| 713 | COMPAT_SYSCALL_DEFINE5(pwrite64, unsigned int, fd, const char __user *, buf, |
| 714 | size_t, count, compat_arg_u64_dual(pos)) |
| 715 | { |
| 716 | return ksys_pwrite64(fd, buf, count, compat_arg_u64_glue(pos)); |
| 717 | } |
| 718 | #endif |
| 719 | |
| 720 | static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter, |
| 721 | loff_t *ppos, int type, rwf_t flags) |
| 722 | { |
| 723 | struct kiocb kiocb; |
| 724 | ssize_t ret; |
| 725 | |
| 726 | init_sync_kiocb(&kiocb, filp); |
| 727 | ret = kiocb_set_rw_flags(&kiocb, flags); |
| 728 | if (ret) |
| 729 | return ret; |
| 730 | kiocb.ki_pos = (ppos ? *ppos : 0); |
| 731 | |
| 732 | if (type == READ) |
| 733 | ret = call_read_iter(filp, &kiocb, iter); |
| 734 | else |
| 735 | ret = call_write_iter(filp, &kiocb, iter); |
| 736 | BUG_ON(ret == -EIOCBQUEUED); |
| 737 | if (ppos) |
| 738 | *ppos = kiocb.ki_pos; |
| 739 | return ret; |
| 740 | } |
| 741 | |
| 742 | /* Do it by hand, with file-ops */ |
| 743 | static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter, |
| 744 | loff_t *ppos, int type, rwf_t flags) |
| 745 | { |
| 746 | ssize_t ret = 0; |
| 747 | |
| 748 | if (flags & ~RWF_HIPRI) |
| 749 | return -EOPNOTSUPP; |
| 750 | |
| 751 | while (iov_iter_count(iter)) { |
| 752 | ssize_t nr; |
| 753 | |
| 754 | if (type == READ) { |
| 755 | nr = filp->f_op->read(filp, iter_iov_addr(iter), |
| 756 | iter_iov_len(iter), ppos); |
| 757 | } else { |
| 758 | nr = filp->f_op->write(filp, iter_iov_addr(iter), |
| 759 | iter_iov_len(iter), ppos); |
| 760 | } |
| 761 | |
| 762 | if (nr < 0) { |
| 763 | if (!ret) |
| 764 | ret = nr; |
| 765 | break; |
| 766 | } |
| 767 | ret += nr; |
| 768 | if (nr != iter_iov_len(iter)) |
| 769 | break; |
| 770 | iov_iter_advance(iter, nr); |
| 771 | } |
| 772 | |
| 773 | return ret; |
| 774 | } |
| 775 | |
| 776 | static ssize_t do_iter_read(struct file *file, struct iov_iter *iter, |
| 777 | loff_t *pos, rwf_t flags) |
| 778 | { |
| 779 | size_t tot_len; |
| 780 | ssize_t ret = 0; |
| 781 | |
| 782 | if (!(file->f_mode & FMODE_READ)) |
| 783 | return -EBADF; |
| 784 | if (!(file->f_mode & FMODE_CAN_READ)) |
| 785 | return -EINVAL; |
| 786 | |
| 787 | tot_len = iov_iter_count(iter); |
| 788 | if (!tot_len) |
| 789 | goto out; |
| 790 | ret = rw_verify_area(READ, file, pos, tot_len); |
| 791 | if (ret < 0) |
| 792 | return ret; |
| 793 | |
| 794 | if (file->f_op->read_iter) |
| 795 | ret = do_iter_readv_writev(file, iter, pos, READ, flags); |
| 796 | else |
| 797 | ret = do_loop_readv_writev(file, iter, pos, READ, flags); |
| 798 | out: |
| 799 | if (ret >= 0) |
| 800 | fsnotify_access(file); |
| 801 | return ret; |
| 802 | } |
| 803 | |
| 804 | ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb, |
| 805 | struct iov_iter *iter) |
| 806 | { |
| 807 | size_t tot_len; |
| 808 | ssize_t ret = 0; |
| 809 | |
| 810 | if (!file->f_op->read_iter) |
| 811 | return -EINVAL; |
| 812 | if (!(file->f_mode & FMODE_READ)) |
| 813 | return -EBADF; |
| 814 | if (!(file->f_mode & FMODE_CAN_READ)) |
| 815 | return -EINVAL; |
| 816 | |
| 817 | tot_len = iov_iter_count(iter); |
| 818 | if (!tot_len) |
| 819 | goto out; |
| 820 | ret = rw_verify_area(READ, file, &iocb->ki_pos, tot_len); |
| 821 | if (ret < 0) |
| 822 | return ret; |
| 823 | |
| 824 | ret = call_read_iter(file, iocb, iter); |
| 825 | out: |
| 826 | if (ret >= 0) |
| 827 | fsnotify_access(file); |
| 828 | return ret; |
| 829 | } |
| 830 | EXPORT_SYMBOL(vfs_iocb_iter_read); |
| 831 | |
| 832 | ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos, |
| 833 | rwf_t flags) |
| 834 | { |
| 835 | if (!file->f_op->read_iter) |
| 836 | return -EINVAL; |
| 837 | return do_iter_read(file, iter, ppos, flags); |
| 838 | } |
| 839 | EXPORT_SYMBOL(vfs_iter_read); |
| 840 | |
| 841 | static ssize_t do_iter_write(struct file *file, struct iov_iter *iter, |
| 842 | loff_t *pos, rwf_t flags) |
| 843 | { |
| 844 | size_t tot_len; |
| 845 | ssize_t ret = 0; |
| 846 | |
| 847 | if (!(file->f_mode & FMODE_WRITE)) |
| 848 | return -EBADF; |
| 849 | if (!(file->f_mode & FMODE_CAN_WRITE)) |
| 850 | return -EINVAL; |
| 851 | |
| 852 | tot_len = iov_iter_count(iter); |
| 853 | if (!tot_len) |
| 854 | return 0; |
| 855 | ret = rw_verify_area(WRITE, file, pos, tot_len); |
| 856 | if (ret < 0) |
| 857 | return ret; |
| 858 | |
| 859 | if (file->f_op->write_iter) |
| 860 | ret = do_iter_readv_writev(file, iter, pos, WRITE, flags); |
| 861 | else |
| 862 | ret = do_loop_readv_writev(file, iter, pos, WRITE, flags); |
| 863 | if (ret > 0) |
| 864 | fsnotify_modify(file); |
| 865 | return ret; |
| 866 | } |
| 867 | |
| 868 | ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb, |
| 869 | struct iov_iter *iter) |
| 870 | { |
| 871 | size_t tot_len; |
| 872 | ssize_t ret = 0; |
| 873 | |
| 874 | if (!file->f_op->write_iter) |
| 875 | return -EINVAL; |
| 876 | if (!(file->f_mode & FMODE_WRITE)) |
| 877 | return -EBADF; |
| 878 | if (!(file->f_mode & FMODE_CAN_WRITE)) |
| 879 | return -EINVAL; |
| 880 | |
| 881 | tot_len = iov_iter_count(iter); |
| 882 | if (!tot_len) |
| 883 | return 0; |
| 884 | ret = rw_verify_area(WRITE, file, &iocb->ki_pos, tot_len); |
| 885 | if (ret < 0) |
| 886 | return ret; |
| 887 | |
| 888 | ret = call_write_iter(file, iocb, iter); |
| 889 | if (ret > 0) |
| 890 | fsnotify_modify(file); |
| 891 | |
| 892 | return ret; |
| 893 | } |
| 894 | EXPORT_SYMBOL(vfs_iocb_iter_write); |
| 895 | |
| 896 | ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos, |
| 897 | rwf_t flags) |
| 898 | { |
| 899 | if (!file->f_op->write_iter) |
| 900 | return -EINVAL; |
| 901 | return do_iter_write(file, iter, ppos, flags); |
| 902 | } |
| 903 | EXPORT_SYMBOL(vfs_iter_write); |
| 904 | |
| 905 | static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec, |
| 906 | unsigned long vlen, loff_t *pos, rwf_t flags) |
| 907 | { |
| 908 | struct iovec iovstack[UIO_FASTIOV]; |
| 909 | struct iovec *iov = iovstack; |
| 910 | struct iov_iter iter; |
| 911 | ssize_t ret; |
| 912 | |
| 913 | ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); |
| 914 | if (ret >= 0) { |
| 915 | ret = do_iter_read(file, &iter, pos, flags); |
| 916 | kfree(iov); |
| 917 | } |
| 918 | |
| 919 | return ret; |
| 920 | } |
| 921 | |
| 922 | static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec, |
| 923 | unsigned long vlen, loff_t *pos, rwf_t flags) |
| 924 | { |
| 925 | struct iovec iovstack[UIO_FASTIOV]; |
| 926 | struct iovec *iov = iovstack; |
| 927 | struct iov_iter iter; |
| 928 | ssize_t ret; |
| 929 | |
| 930 | ret = import_iovec(ITER_SOURCE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter); |
| 931 | if (ret >= 0) { |
| 932 | file_start_write(file); |
| 933 | ret = do_iter_write(file, &iter, pos, flags); |
| 934 | file_end_write(file); |
| 935 | kfree(iov); |
| 936 | } |
| 937 | return ret; |
| 938 | } |
| 939 | |
| 940 | static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec, |
| 941 | unsigned long vlen, rwf_t flags) |
| 942 | { |
| 943 | struct fd f = fdget_pos(fd); |
| 944 | ssize_t ret = -EBADF; |
| 945 | |
| 946 | if (f.file) { |
| 947 | loff_t pos, *ppos = file_ppos(f.file); |
| 948 | if (ppos) { |
| 949 | pos = *ppos; |
| 950 | ppos = &pos; |
| 951 | } |
| 952 | ret = vfs_readv(f.file, vec, vlen, ppos, flags); |
| 953 | if (ret >= 0 && ppos) |
| 954 | f.file->f_pos = pos; |
| 955 | fdput_pos(f); |
| 956 | } |
| 957 | |
| 958 | if (ret > 0) |
| 959 | add_rchar(current, ret); |
| 960 | inc_syscr(current); |
| 961 | return ret; |
| 962 | } |
| 963 | |
| 964 | static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec, |
| 965 | unsigned long vlen, rwf_t flags) |
| 966 | { |
| 967 | struct fd f = fdget_pos(fd); |
| 968 | ssize_t ret = -EBADF; |
| 969 | |
| 970 | if (f.file) { |
| 971 | loff_t pos, *ppos = file_ppos(f.file); |
| 972 | if (ppos) { |
| 973 | pos = *ppos; |
| 974 | ppos = &pos; |
| 975 | } |
| 976 | ret = vfs_writev(f.file, vec, vlen, ppos, flags); |
| 977 | if (ret >= 0 && ppos) |
| 978 | f.file->f_pos = pos; |
| 979 | fdput_pos(f); |
| 980 | } |
| 981 | |
| 982 | if (ret > 0) |
| 983 | add_wchar(current, ret); |
| 984 | inc_syscw(current); |
| 985 | return ret; |
| 986 | } |
| 987 | |
| 988 | static inline loff_t pos_from_hilo(unsigned long high, unsigned long low) |
| 989 | { |
| 990 | #define HALF_LONG_BITS (BITS_PER_LONG / 2) |
| 991 | return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low; |
| 992 | } |
| 993 | |
| 994 | static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec, |
| 995 | unsigned long vlen, loff_t pos, rwf_t flags) |
| 996 | { |
| 997 | struct fd f; |
| 998 | ssize_t ret = -EBADF; |
| 999 | |
| 1000 | if (pos < 0) |
| 1001 | return -EINVAL; |
| 1002 | |
| 1003 | f = fdget(fd); |
| 1004 | if (f.file) { |
| 1005 | ret = -ESPIPE; |
| 1006 | if (f.file->f_mode & FMODE_PREAD) |
| 1007 | ret = vfs_readv(f.file, vec, vlen, &pos, flags); |
| 1008 | fdput(f); |
| 1009 | } |
| 1010 | |
| 1011 | if (ret > 0) |
| 1012 | add_rchar(current, ret); |
| 1013 | inc_syscr(current); |
| 1014 | return ret; |
| 1015 | } |
| 1016 | |
| 1017 | static ssize_t do_pwritev(unsigned long fd, const struct iovec __user *vec, |
| 1018 | unsigned long vlen, loff_t pos, rwf_t flags) |
| 1019 | { |
| 1020 | struct fd f; |
| 1021 | ssize_t ret = -EBADF; |
| 1022 | |
| 1023 | if (pos < 0) |
| 1024 | return -EINVAL; |
| 1025 | |
| 1026 | f = fdget(fd); |
| 1027 | if (f.file) { |
| 1028 | ret = -ESPIPE; |
| 1029 | if (f.file->f_mode & FMODE_PWRITE) |
| 1030 | ret = vfs_writev(f.file, vec, vlen, &pos, flags); |
| 1031 | fdput(f); |
| 1032 | } |
| 1033 | |
| 1034 | if (ret > 0) |
| 1035 | add_wchar(current, ret); |
| 1036 | inc_syscw(current); |
| 1037 | return ret; |
| 1038 | } |
| 1039 | |
| 1040 | SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec, |
| 1041 | unsigned long, vlen) |
| 1042 | { |
| 1043 | return do_readv(fd, vec, vlen, 0); |
| 1044 | } |
| 1045 | |
| 1046 | SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec, |
| 1047 | unsigned long, vlen) |
| 1048 | { |
| 1049 | return do_writev(fd, vec, vlen, 0); |
| 1050 | } |
| 1051 | |
| 1052 | SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec, |
| 1053 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
| 1054 | { |
| 1055 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
| 1056 | |
| 1057 | return do_preadv(fd, vec, vlen, pos, 0); |
| 1058 | } |
| 1059 | |
| 1060 | SYSCALL_DEFINE6(preadv2, unsigned long, fd, const struct iovec __user *, vec, |
| 1061 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h, |
| 1062 | rwf_t, flags) |
| 1063 | { |
| 1064 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
| 1065 | |
| 1066 | if (pos == -1) |
| 1067 | return do_readv(fd, vec, vlen, flags); |
| 1068 | |
| 1069 | return do_preadv(fd, vec, vlen, pos, flags); |
| 1070 | } |
| 1071 | |
| 1072 | SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec, |
| 1073 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h) |
| 1074 | { |
| 1075 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
| 1076 | |
| 1077 | return do_pwritev(fd, vec, vlen, pos, 0); |
| 1078 | } |
| 1079 | |
| 1080 | SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec, |
| 1081 | unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h, |
| 1082 | rwf_t, flags) |
| 1083 | { |
| 1084 | loff_t pos = pos_from_hilo(pos_h, pos_l); |
| 1085 | |
| 1086 | if (pos == -1) |
| 1087 | return do_writev(fd, vec, vlen, flags); |
| 1088 | |
| 1089 | return do_pwritev(fd, vec, vlen, pos, flags); |
| 1090 | } |
| 1091 | |
| 1092 | /* |
| 1093 | * Various compat syscalls. Note that they all pretend to take a native |
| 1094 | * iovec - import_iovec will properly treat those as compat_iovecs based on |
| 1095 | * in_compat_syscall(). |
| 1096 | */ |
| 1097 | #ifdef CONFIG_COMPAT |
| 1098 | #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64 |
| 1099 | COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd, |
| 1100 | const struct iovec __user *, vec, |
| 1101 | unsigned long, vlen, loff_t, pos) |
| 1102 | { |
| 1103 | return do_preadv(fd, vec, vlen, pos, 0); |
| 1104 | } |
| 1105 | #endif |
| 1106 | |
| 1107 | COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd, |
| 1108 | const struct iovec __user *, vec, |
| 1109 | compat_ulong_t, vlen, u32, pos_low, u32, pos_high) |
| 1110 | { |
| 1111 | loff_t pos = ((loff_t)pos_high << 32) | pos_low; |
| 1112 | |
| 1113 | return do_preadv(fd, vec, vlen, pos, 0); |
| 1114 | } |
| 1115 | |
| 1116 | #ifdef __ARCH_WANT_COMPAT_SYS_PREADV64V2 |
| 1117 | COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd, |
| 1118 | const struct iovec __user *, vec, |
| 1119 | unsigned long, vlen, loff_t, pos, rwf_t, flags) |
| 1120 | { |
| 1121 | if (pos == -1) |
| 1122 | return do_readv(fd, vec, vlen, flags); |
| 1123 | return do_preadv(fd, vec, vlen, pos, flags); |
| 1124 | } |
| 1125 | #endif |
| 1126 | |
| 1127 | COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd, |
| 1128 | const struct iovec __user *, vec, |
| 1129 | compat_ulong_t, vlen, u32, pos_low, u32, pos_high, |
| 1130 | rwf_t, flags) |
| 1131 | { |
| 1132 | loff_t pos = ((loff_t)pos_high << 32) | pos_low; |
| 1133 | |
| 1134 | if (pos == -1) |
| 1135 | return do_readv(fd, vec, vlen, flags); |
| 1136 | return do_preadv(fd, vec, vlen, pos, flags); |
| 1137 | } |
| 1138 | |
| 1139 | #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64 |
| 1140 | COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd, |
| 1141 | const struct iovec __user *, vec, |
| 1142 | unsigned long, vlen, loff_t, pos) |
| 1143 | { |
| 1144 | return do_pwritev(fd, vec, vlen, pos, 0); |
| 1145 | } |
| 1146 | #endif |
| 1147 | |
| 1148 | COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd, |
| 1149 | const struct iovec __user *,vec, |
| 1150 | compat_ulong_t, vlen, u32, pos_low, u32, pos_high) |
| 1151 | { |
| 1152 | loff_t pos = ((loff_t)pos_high << 32) | pos_low; |
| 1153 | |
| 1154 | return do_pwritev(fd, vec, vlen, pos, 0); |
| 1155 | } |
| 1156 | |
| 1157 | #ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64V2 |
| 1158 | COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd, |
| 1159 | const struct iovec __user *, vec, |
| 1160 | unsigned long, vlen, loff_t, pos, rwf_t, flags) |
| 1161 | { |
| 1162 | if (pos == -1) |
| 1163 | return do_writev(fd, vec, vlen, flags); |
| 1164 | return do_pwritev(fd, vec, vlen, pos, flags); |
| 1165 | } |
| 1166 | #endif |
| 1167 | |
| 1168 | COMPAT_SYSCALL_DEFINE6(pwritev2, compat_ulong_t, fd, |
| 1169 | const struct iovec __user *,vec, |
| 1170 | compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags) |
| 1171 | { |
| 1172 | loff_t pos = ((loff_t)pos_high << 32) | pos_low; |
| 1173 | |
| 1174 | if (pos == -1) |
| 1175 | return do_writev(fd, vec, vlen, flags); |
| 1176 | return do_pwritev(fd, vec, vlen, pos, flags); |
| 1177 | } |
| 1178 | #endif /* CONFIG_COMPAT */ |
| 1179 | |
| 1180 | static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos, |
| 1181 | size_t count, loff_t max) |
| 1182 | { |
| 1183 | struct fd in, out; |
| 1184 | struct inode *in_inode, *out_inode; |
| 1185 | struct pipe_inode_info *opipe; |
| 1186 | loff_t pos; |
| 1187 | loff_t out_pos; |
| 1188 | ssize_t retval; |
| 1189 | int fl; |
| 1190 | |
| 1191 | /* |
| 1192 | * Get input file, and verify that it is ok.. |
| 1193 | */ |
| 1194 | retval = -EBADF; |
| 1195 | in = fdget(in_fd); |
| 1196 | if (!in.file) |
| 1197 | goto out; |
| 1198 | if (!(in.file->f_mode & FMODE_READ)) |
| 1199 | goto fput_in; |
| 1200 | retval = -ESPIPE; |
| 1201 | if (!ppos) { |
| 1202 | pos = in.file->f_pos; |
| 1203 | } else { |
| 1204 | pos = *ppos; |
| 1205 | if (!(in.file->f_mode & FMODE_PREAD)) |
| 1206 | goto fput_in; |
| 1207 | } |
| 1208 | retval = rw_verify_area(READ, in.file, &pos, count); |
| 1209 | if (retval < 0) |
| 1210 | goto fput_in; |
| 1211 | if (count > MAX_RW_COUNT) |
| 1212 | count = MAX_RW_COUNT; |
| 1213 | |
| 1214 | /* |
| 1215 | * Get output file, and verify that it is ok.. |
| 1216 | */ |
| 1217 | retval = -EBADF; |
| 1218 | out = fdget(out_fd); |
| 1219 | if (!out.file) |
| 1220 | goto fput_in; |
| 1221 | if (!(out.file->f_mode & FMODE_WRITE)) |
| 1222 | goto fput_out; |
| 1223 | in_inode = file_inode(in.file); |
| 1224 | out_inode = file_inode(out.file); |
| 1225 | out_pos = out.file->f_pos; |
| 1226 | |
| 1227 | if (!max) |
| 1228 | max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes); |
| 1229 | |
| 1230 | if (unlikely(pos + count > max)) { |
| 1231 | retval = -EOVERFLOW; |
| 1232 | if (pos >= max) |
| 1233 | goto fput_out; |
| 1234 | count = max - pos; |
| 1235 | } |
| 1236 | |
| 1237 | fl = 0; |
| 1238 | #if 0 |
| 1239 | /* |
| 1240 | * We need to debate whether we can enable this or not. The |
| 1241 | * man page documents EAGAIN return for the output at least, |
| 1242 | * and the application is arguably buggy if it doesn't expect |
| 1243 | * EAGAIN on a non-blocking file descriptor. |
| 1244 | */ |
| 1245 | if (in.file->f_flags & O_NONBLOCK) |
| 1246 | fl = SPLICE_F_NONBLOCK; |
| 1247 | #endif |
| 1248 | opipe = get_pipe_info(out.file, true); |
| 1249 | if (!opipe) { |
| 1250 | retval = rw_verify_area(WRITE, out.file, &out_pos, count); |
| 1251 | if (retval < 0) |
| 1252 | goto fput_out; |
| 1253 | file_start_write(out.file); |
| 1254 | retval = do_splice_direct(in.file, &pos, out.file, &out_pos, |
| 1255 | count, fl); |
| 1256 | file_end_write(out.file); |
| 1257 | } else { |
| 1258 | if (out.file->f_flags & O_NONBLOCK) |
| 1259 | fl |= SPLICE_F_NONBLOCK; |
| 1260 | |
| 1261 | retval = splice_file_to_pipe(in.file, opipe, &pos, count, fl); |
| 1262 | } |
| 1263 | |
| 1264 | if (retval > 0) { |
| 1265 | add_rchar(current, retval); |
| 1266 | add_wchar(current, retval); |
| 1267 | fsnotify_access(in.file); |
| 1268 | fsnotify_modify(out.file); |
| 1269 | out.file->f_pos = out_pos; |
| 1270 | if (ppos) |
| 1271 | *ppos = pos; |
| 1272 | else |
| 1273 | in.file->f_pos = pos; |
| 1274 | } |
| 1275 | |
| 1276 | inc_syscr(current); |
| 1277 | inc_syscw(current); |
| 1278 | if (pos > max) |
| 1279 | retval = -EOVERFLOW; |
| 1280 | |
| 1281 | fput_out: |
| 1282 | fdput(out); |
| 1283 | fput_in: |
| 1284 | fdput(in); |
| 1285 | out: |
| 1286 | return retval; |
| 1287 | } |
| 1288 | |
| 1289 | SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count) |
| 1290 | { |
| 1291 | loff_t pos; |
| 1292 | off_t off; |
| 1293 | ssize_t ret; |
| 1294 | |
| 1295 | if (offset) { |
| 1296 | if (unlikely(get_user(off, offset))) |
| 1297 | return -EFAULT; |
| 1298 | pos = off; |
| 1299 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); |
| 1300 | if (unlikely(put_user(pos, offset))) |
| 1301 | return -EFAULT; |
| 1302 | return ret; |
| 1303 | } |
| 1304 | |
| 1305 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
| 1306 | } |
| 1307 | |
| 1308 | SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count) |
| 1309 | { |
| 1310 | loff_t pos; |
| 1311 | ssize_t ret; |
| 1312 | |
| 1313 | if (offset) { |
| 1314 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) |
| 1315 | return -EFAULT; |
| 1316 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); |
| 1317 | if (unlikely(put_user(pos, offset))) |
| 1318 | return -EFAULT; |
| 1319 | return ret; |
| 1320 | } |
| 1321 | |
| 1322 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
| 1323 | } |
| 1324 | |
| 1325 | #ifdef CONFIG_COMPAT |
| 1326 | COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, |
| 1327 | compat_off_t __user *, offset, compat_size_t, count) |
| 1328 | { |
| 1329 | loff_t pos; |
| 1330 | off_t off; |
| 1331 | ssize_t ret; |
| 1332 | |
| 1333 | if (offset) { |
| 1334 | if (unlikely(get_user(off, offset))) |
| 1335 | return -EFAULT; |
| 1336 | pos = off; |
| 1337 | ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS); |
| 1338 | if (unlikely(put_user(pos, offset))) |
| 1339 | return -EFAULT; |
| 1340 | return ret; |
| 1341 | } |
| 1342 | |
| 1343 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
| 1344 | } |
| 1345 | |
| 1346 | COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, |
| 1347 | compat_loff_t __user *, offset, compat_size_t, count) |
| 1348 | { |
| 1349 | loff_t pos; |
| 1350 | ssize_t ret; |
| 1351 | |
| 1352 | if (offset) { |
| 1353 | if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t)))) |
| 1354 | return -EFAULT; |
| 1355 | ret = do_sendfile(out_fd, in_fd, &pos, count, 0); |
| 1356 | if (unlikely(put_user(pos, offset))) |
| 1357 | return -EFAULT; |
| 1358 | return ret; |
| 1359 | } |
| 1360 | |
| 1361 | return do_sendfile(out_fd, in_fd, NULL, count, 0); |
| 1362 | } |
| 1363 | #endif |
| 1364 | |
| 1365 | /** |
| 1366 | * generic_copy_file_range - copy data between two files |
| 1367 | * @file_in: file structure to read from |
| 1368 | * @pos_in: file offset to read from |
| 1369 | * @file_out: file structure to write data to |
| 1370 | * @pos_out: file offset to write data to |
| 1371 | * @len: amount of data to copy |
| 1372 | * @flags: copy flags |
| 1373 | * |
| 1374 | * This is a generic filesystem helper to copy data from one file to another. |
| 1375 | * It has no constraints on the source or destination file owners - the files |
| 1376 | * can belong to different superblocks and different filesystem types. Short |
| 1377 | * copies are allowed. |
| 1378 | * |
| 1379 | * This should be called from the @file_out filesystem, as per the |
| 1380 | * ->copy_file_range() method. |
| 1381 | * |
| 1382 | * Returns the number of bytes copied or a negative error indicating the |
| 1383 | * failure. |
| 1384 | */ |
| 1385 | |
| 1386 | ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in, |
| 1387 | struct file *file_out, loff_t pos_out, |
| 1388 | size_t len, unsigned int flags) |
| 1389 | { |
| 1390 | lockdep_assert(sb_write_started(file_inode(file_out)->i_sb)); |
| 1391 | |
| 1392 | return do_splice_direct(file_in, &pos_in, file_out, &pos_out, |
| 1393 | len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0); |
| 1394 | } |
| 1395 | EXPORT_SYMBOL(generic_copy_file_range); |
| 1396 | |
| 1397 | /* |
| 1398 | * Performs necessary checks before doing a file copy |
| 1399 | * |
| 1400 | * Can adjust amount of bytes to copy via @req_count argument. |
| 1401 | * Returns appropriate error code that caller should return or |
| 1402 | * zero in case the copy should be allowed. |
| 1403 | */ |
| 1404 | static int generic_copy_file_checks(struct file *file_in, loff_t pos_in, |
| 1405 | struct file *file_out, loff_t pos_out, |
| 1406 | size_t *req_count, unsigned int flags) |
| 1407 | { |
| 1408 | struct inode *inode_in = file_inode(file_in); |
| 1409 | struct inode *inode_out = file_inode(file_out); |
| 1410 | uint64_t count = *req_count; |
| 1411 | loff_t size_in; |
| 1412 | int ret; |
| 1413 | |
| 1414 | ret = generic_file_rw_checks(file_in, file_out); |
| 1415 | if (ret) |
| 1416 | return ret; |
| 1417 | |
| 1418 | /* |
| 1419 | * We allow some filesystems to handle cross sb copy, but passing |
| 1420 | * a file of the wrong filesystem type to filesystem driver can result |
| 1421 | * in an attempt to dereference the wrong type of ->private_data, so |
| 1422 | * avoid doing that until we really have a good reason. |
| 1423 | * |
| 1424 | * nfs and cifs define several different file_system_type structures |
| 1425 | * and several different sets of file_operations, but they all end up |
| 1426 | * using the same ->copy_file_range() function pointer. |
| 1427 | */ |
| 1428 | if (flags & COPY_FILE_SPLICE) { |
| 1429 | /* cross sb splice is allowed */ |
| 1430 | } else if (file_out->f_op->copy_file_range) { |
| 1431 | if (file_in->f_op->copy_file_range != |
| 1432 | file_out->f_op->copy_file_range) |
| 1433 | return -EXDEV; |
| 1434 | } else if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) { |
| 1435 | return -EXDEV; |
| 1436 | } |
| 1437 | |
| 1438 | /* Don't touch certain kinds of inodes */ |
| 1439 | if (IS_IMMUTABLE(inode_out)) |
| 1440 | return -EPERM; |
| 1441 | |
| 1442 | if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out)) |
| 1443 | return -ETXTBSY; |
| 1444 | |
| 1445 | /* Ensure offsets don't wrap. */ |
| 1446 | if (pos_in + count < pos_in || pos_out + count < pos_out) |
| 1447 | return -EOVERFLOW; |
| 1448 | |
| 1449 | /* Shorten the copy to EOF */ |
| 1450 | size_in = i_size_read(inode_in); |
| 1451 | if (pos_in >= size_in) |
| 1452 | count = 0; |
| 1453 | else |
| 1454 | count = min(count, size_in - (uint64_t)pos_in); |
| 1455 | |
| 1456 | ret = generic_write_check_limits(file_out, pos_out, &count); |
| 1457 | if (ret) |
| 1458 | return ret; |
| 1459 | |
| 1460 | /* Don't allow overlapped copying within the same file. */ |
| 1461 | if (inode_in == inode_out && |
| 1462 | pos_out + count > pos_in && |
| 1463 | pos_out < pos_in + count) |
| 1464 | return -EINVAL; |
| 1465 | |
| 1466 | *req_count = count; |
| 1467 | return 0; |
| 1468 | } |
| 1469 | |
| 1470 | /* |
| 1471 | * copy_file_range() differs from regular file read and write in that it |
| 1472 | * specifically allows return partial success. When it does so is up to |
| 1473 | * the copy_file_range method. |
| 1474 | */ |
| 1475 | ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in, |
| 1476 | struct file *file_out, loff_t pos_out, |
| 1477 | size_t len, unsigned int flags) |
| 1478 | { |
| 1479 | ssize_t ret; |
| 1480 | bool splice = flags & COPY_FILE_SPLICE; |
| 1481 | |
| 1482 | if (flags & ~COPY_FILE_SPLICE) |
| 1483 | return -EINVAL; |
| 1484 | |
| 1485 | ret = generic_copy_file_checks(file_in, pos_in, file_out, pos_out, &len, |
| 1486 | flags); |
| 1487 | if (unlikely(ret)) |
| 1488 | return ret; |
| 1489 | |
| 1490 | ret = rw_verify_area(READ, file_in, &pos_in, len); |
| 1491 | if (unlikely(ret)) |
| 1492 | return ret; |
| 1493 | |
| 1494 | ret = rw_verify_area(WRITE, file_out, &pos_out, len); |
| 1495 | if (unlikely(ret)) |
| 1496 | return ret; |
| 1497 | |
| 1498 | if (len == 0) |
| 1499 | return 0; |
| 1500 | |
| 1501 | file_start_write(file_out); |
| 1502 | |
| 1503 | /* |
| 1504 | * Cloning is supported by more file systems, so we implement copy on |
| 1505 | * same sb using clone, but for filesystems where both clone and copy |
| 1506 | * are supported (e.g. nfs,cifs), we only call the copy method. |
| 1507 | */ |
| 1508 | if (!splice && file_out->f_op->copy_file_range) { |
| 1509 | ret = file_out->f_op->copy_file_range(file_in, pos_in, |
| 1510 | file_out, pos_out, |
| 1511 | len, flags); |
| 1512 | goto done; |
| 1513 | } |
| 1514 | |
| 1515 | if (!splice && file_in->f_op->remap_file_range && |
| 1516 | file_inode(file_in)->i_sb == file_inode(file_out)->i_sb) { |
| 1517 | ret = file_in->f_op->remap_file_range(file_in, pos_in, |
| 1518 | file_out, pos_out, |
| 1519 | min_t(loff_t, MAX_RW_COUNT, len), |
| 1520 | REMAP_FILE_CAN_SHORTEN); |
| 1521 | if (ret > 0) |
| 1522 | goto done; |
| 1523 | } |
| 1524 | |
| 1525 | /* |
| 1526 | * We can get here for same sb copy of filesystems that do not implement |
| 1527 | * ->copy_file_range() in case filesystem does not support clone or in |
| 1528 | * case filesystem supports clone but rejected the clone request (e.g. |
| 1529 | * because it was not block aligned). |
| 1530 | * |
| 1531 | * In both cases, fall back to kernel copy so we are able to maintain a |
| 1532 | * consistent story about which filesystems support copy_file_range() |
| 1533 | * and which filesystems do not, that will allow userspace tools to |
| 1534 | * make consistent desicions w.r.t using copy_file_range(). |
| 1535 | * |
| 1536 | * We also get here if caller (e.g. nfsd) requested COPY_FILE_SPLICE. |
| 1537 | */ |
| 1538 | ret = generic_copy_file_range(file_in, pos_in, file_out, pos_out, len, |
| 1539 | flags); |
| 1540 | |
| 1541 | done: |
| 1542 | if (ret > 0) { |
| 1543 | fsnotify_access(file_in); |
| 1544 | add_rchar(current, ret); |
| 1545 | fsnotify_modify(file_out); |
| 1546 | add_wchar(current, ret); |
| 1547 | } |
| 1548 | |
| 1549 | inc_syscr(current); |
| 1550 | inc_syscw(current); |
| 1551 | |
| 1552 | file_end_write(file_out); |
| 1553 | |
| 1554 | return ret; |
| 1555 | } |
| 1556 | EXPORT_SYMBOL(vfs_copy_file_range); |
| 1557 | |
| 1558 | SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in, |
| 1559 | int, fd_out, loff_t __user *, off_out, |
| 1560 | size_t, len, unsigned int, flags) |
| 1561 | { |
| 1562 | loff_t pos_in; |
| 1563 | loff_t pos_out; |
| 1564 | struct fd f_in; |
| 1565 | struct fd f_out; |
| 1566 | ssize_t ret = -EBADF; |
| 1567 | |
| 1568 | f_in = fdget(fd_in); |
| 1569 | if (!f_in.file) |
| 1570 | goto out2; |
| 1571 | |
| 1572 | f_out = fdget(fd_out); |
| 1573 | if (!f_out.file) |
| 1574 | goto out1; |
| 1575 | |
| 1576 | ret = -EFAULT; |
| 1577 | if (off_in) { |
| 1578 | if (copy_from_user(&pos_in, off_in, sizeof(loff_t))) |
| 1579 | goto out; |
| 1580 | } else { |
| 1581 | pos_in = f_in.file->f_pos; |
| 1582 | } |
| 1583 | |
| 1584 | if (off_out) { |
| 1585 | if (copy_from_user(&pos_out, off_out, sizeof(loff_t))) |
| 1586 | goto out; |
| 1587 | } else { |
| 1588 | pos_out = f_out.file->f_pos; |
| 1589 | } |
| 1590 | |
| 1591 | ret = -EINVAL; |
| 1592 | if (flags != 0) |
| 1593 | goto out; |
| 1594 | |
| 1595 | ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len, |
| 1596 | flags); |
| 1597 | if (ret > 0) { |
| 1598 | pos_in += ret; |
| 1599 | pos_out += ret; |
| 1600 | |
| 1601 | if (off_in) { |
| 1602 | if (copy_to_user(off_in, &pos_in, sizeof(loff_t))) |
| 1603 | ret = -EFAULT; |
| 1604 | } else { |
| 1605 | f_in.file->f_pos = pos_in; |
| 1606 | } |
| 1607 | |
| 1608 | if (off_out) { |
| 1609 | if (copy_to_user(off_out, &pos_out, sizeof(loff_t))) |
| 1610 | ret = -EFAULT; |
| 1611 | } else { |
| 1612 | f_out.file->f_pos = pos_out; |
| 1613 | } |
| 1614 | } |
| 1615 | |
| 1616 | out: |
| 1617 | fdput(f_out); |
| 1618 | out1: |
| 1619 | fdput(f_in); |
| 1620 | out2: |
| 1621 | return ret; |
| 1622 | } |
| 1623 | |
| 1624 | /* |
| 1625 | * Don't operate on ranges the page cache doesn't support, and don't exceed the |
| 1626 | * LFS limits. If pos is under the limit it becomes a short access. If it |
| 1627 | * exceeds the limit we return -EFBIG. |
| 1628 | */ |
| 1629 | int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count) |
| 1630 | { |
| 1631 | struct inode *inode = file->f_mapping->host; |
| 1632 | loff_t max_size = inode->i_sb->s_maxbytes; |
| 1633 | loff_t limit = rlimit(RLIMIT_FSIZE); |
| 1634 | |
| 1635 | if (limit != RLIM_INFINITY) { |
| 1636 | if (pos >= limit) { |
| 1637 | send_sig(SIGXFSZ, current, 0); |
| 1638 | return -EFBIG; |
| 1639 | } |
| 1640 | *count = min(*count, limit - pos); |
| 1641 | } |
| 1642 | |
| 1643 | if (!(file->f_flags & O_LARGEFILE)) |
| 1644 | max_size = MAX_NON_LFS; |
| 1645 | |
| 1646 | if (unlikely(pos >= max_size)) |
| 1647 | return -EFBIG; |
| 1648 | |
| 1649 | *count = min(*count, max_size - pos); |
| 1650 | |
| 1651 | return 0; |
| 1652 | } |
| 1653 | |
| 1654 | /* Like generic_write_checks(), but takes size of write instead of iter. */ |
| 1655 | int generic_write_checks_count(struct kiocb *iocb, loff_t *count) |
| 1656 | { |
| 1657 | struct file *file = iocb->ki_filp; |
| 1658 | struct inode *inode = file->f_mapping->host; |
| 1659 | |
| 1660 | if (IS_SWAPFILE(inode)) |
| 1661 | return -ETXTBSY; |
| 1662 | |
| 1663 | if (!*count) |
| 1664 | return 0; |
| 1665 | |
| 1666 | if (iocb->ki_flags & IOCB_APPEND) |
| 1667 | iocb->ki_pos = i_size_read(inode); |
| 1668 | |
| 1669 | if ((iocb->ki_flags & IOCB_NOWAIT) && |
| 1670 | !((iocb->ki_flags & IOCB_DIRECT) || |
| 1671 | (file->f_mode & FMODE_BUF_WASYNC))) |
| 1672 | return -EINVAL; |
| 1673 | |
| 1674 | return generic_write_check_limits(iocb->ki_filp, iocb->ki_pos, count); |
| 1675 | } |
| 1676 | EXPORT_SYMBOL(generic_write_checks_count); |
| 1677 | |
| 1678 | /* |
| 1679 | * Performs necessary checks before doing a write |
| 1680 | * |
| 1681 | * Can adjust writing position or amount of bytes to write. |
| 1682 | * Returns appropriate error code that caller should return or |
| 1683 | * zero in case that write should be allowed. |
| 1684 | */ |
| 1685 | ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from) |
| 1686 | { |
| 1687 | loff_t count = iov_iter_count(from); |
| 1688 | int ret; |
| 1689 | |
| 1690 | ret = generic_write_checks_count(iocb, &count); |
| 1691 | if (ret) |
| 1692 | return ret; |
| 1693 | |
| 1694 | iov_iter_truncate(from, count); |
| 1695 | return iov_iter_count(from); |
| 1696 | } |
| 1697 | EXPORT_SYMBOL(generic_write_checks); |
| 1698 | |
| 1699 | /* |
| 1700 | * Performs common checks before doing a file copy/clone |
| 1701 | * from @file_in to @file_out. |
| 1702 | */ |
| 1703 | int generic_file_rw_checks(struct file *file_in, struct file *file_out) |
| 1704 | { |
| 1705 | struct inode *inode_in = file_inode(file_in); |
| 1706 | struct inode *inode_out = file_inode(file_out); |
| 1707 | |
| 1708 | /* Don't copy dirs, pipes, sockets... */ |
| 1709 | if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode)) |
| 1710 | return -EISDIR; |
| 1711 | if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) |
| 1712 | return -EINVAL; |
| 1713 | |
| 1714 | if (!(file_in->f_mode & FMODE_READ) || |
| 1715 | !(file_out->f_mode & FMODE_WRITE) || |
| 1716 | (file_out->f_flags & O_APPEND)) |
| 1717 | return -EBADF; |
| 1718 | |
| 1719 | return 0; |
| 1720 | } |