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1// SPDX-License-Identifier: GPL-2.02/*3 * linux/fs/read_write.c4 *5 * Copyright (C) 1991, 1992 Linus Torvalds6 */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 28const 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 = filemap_splice_read,33};34 35EXPORT_SYMBOL(generic_ro_fops);36 37static inline bool unsigned_offsets(struct file *file)38{39 return file->f_op->fop_flags & FOP_UNSIGNED_OFFSET;40}41 42/**43 * vfs_setpos_cookie - update the file offset for lseek and reset cookie44 * @file: file structure in question45 * @offset: file offset to seek to46 * @maxsize: maximum file size47 * @cookie: cookie to reset48 *49 * Update the file offset to the value specified by @offset if the given50 * offset is valid and it is not equal to the current file offset and51 * reset the specified cookie to indicate that a seek happened.52 *53 * Return the specified offset on success and -EINVAL on invalid offset.54 */55static loff_t vfs_setpos_cookie(struct file *file, loff_t offset,56 loff_t maxsize, u64 *cookie)57{58 if (offset < 0 && !unsigned_offsets(file))59 return -EINVAL;60 if (offset > maxsize)61 return -EINVAL;62 63 if (offset != file->f_pos) {64 file->f_pos = offset;65 if (cookie)66 *cookie = 0;67 }68 return offset;69}70 71/**72 * vfs_setpos - update the file offset for lseek73 * @file: file structure in question74 * @offset: file offset to seek to75 * @maxsize: maximum file size76 *77 * This is a low-level filesystem helper for updating the file offset to78 * the value specified by @offset if the given offset is valid and it is79 * not equal to the current file offset.80 *81 * Return the specified offset on success and -EINVAL on invalid offset.82 */83loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)84{85 return vfs_setpos_cookie(file, offset, maxsize, NULL);86}87EXPORT_SYMBOL(vfs_setpos);88 89/**90 * must_set_pos - check whether f_pos has to be updated91 * @file: file to seek on92 * @offset: offset to use93 * @whence: type of seek operation94 * @eof: end of file95 *96 * Check whether f_pos needs to be updated and update @offset according97 * to @whence.98 *99 * Return: 0 if f_pos doesn't need to be updated, 1 if f_pos has to be100 * updated, and negative error code on failure.101 */102static int must_set_pos(struct file *file, loff_t *offset, int whence, loff_t eof)103{104 switch (whence) {105 case SEEK_END:106 *offset += eof;107 break;108 case SEEK_CUR:109 /*110 * Here we special-case the lseek(fd, 0, SEEK_CUR)111 * position-querying operation. Avoid rewriting the "same"112 * f_pos value back to the file because a concurrent read(),113 * write() or lseek() might have altered it114 */115 if (*offset == 0) {116 *offset = file->f_pos;117 return 0;118 }119 break;120 case SEEK_DATA:121 /*122 * In the generic case the entire file is data, so as long as123 * offset isn't at the end of the file then the offset is data.124 */125 if ((unsigned long long)*offset >= eof)126 return -ENXIO;127 break;128 case SEEK_HOLE:129 /*130 * There is a virtual hole at the end of the file, so as long as131 * offset isn't i_size or larger, return i_size.132 */133 if ((unsigned long long)*offset >= eof)134 return -ENXIO;135 *offset = eof;136 break;137 }138 139 return 1;140}141 142/**143 * generic_file_llseek_size - generic llseek implementation for regular files144 * @file: file structure to seek on145 * @offset: file offset to seek to146 * @whence: type of seek147 * @maxsize: max size of this file in file system148 * @eof: offset used for SEEK_END position149 *150 * This is a variant of generic_file_llseek that allows passing in a custom151 * maximum file size and a custom EOF position, for e.g. hashed directories152 *153 * Synchronization:154 * SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)155 * SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.156 * read/writes behave like SEEK_SET against seeks.157 */158loff_t159generic_file_llseek_size(struct file *file, loff_t offset, int whence,160 loff_t maxsize, loff_t eof)161{162 int ret;163 164 ret = must_set_pos(file, &offset, whence, eof);165 if (ret < 0)166 return ret;167 if (ret == 0)168 return offset;169 170 if (whence == SEEK_CUR) {171 /*172 * f_lock protects against read/modify/write race with173 * other SEEK_CURs. Note that parallel writes and reads174 * behave like SEEK_SET.175 */176 guard(spinlock)(&file->f_lock);177 return vfs_setpos(file, file->f_pos + offset, maxsize);178 }179 180 return vfs_setpos(file, offset, maxsize);181}182EXPORT_SYMBOL(generic_file_llseek_size);183 184/**185 * generic_llseek_cookie - versioned llseek implementation186 * @file: file structure to seek on187 * @offset: file offset to seek to188 * @whence: type of seek189 * @cookie: cookie to update190 *191 * See generic_file_llseek for a general description and locking assumptions.192 *193 * In contrast to generic_file_llseek, this function also resets a194 * specified cookie to indicate a seek took place.195 */196loff_t generic_llseek_cookie(struct file *file, loff_t offset, int whence,197 u64 *cookie)198{199 struct inode *inode = file->f_mapping->host;200 loff_t maxsize = inode->i_sb->s_maxbytes;201 loff_t eof = i_size_read(inode);202 int ret;203 204 if (WARN_ON_ONCE(!cookie))205 return -EINVAL;206 207 /*208 * Require that this is only used for directories that guarantee209 * synchronization between readdir and seek so that an update to210 * @cookie is correctly synchronized with concurrent readdir.211 */212 if (WARN_ON_ONCE(!(file->f_mode & FMODE_ATOMIC_POS)))213 return -EINVAL;214 215 ret = must_set_pos(file, &offset, whence, eof);216 if (ret < 0)217 return ret;218 if (ret == 0)219 return offset;220 221 /* No need to hold f_lock because we know that f_pos_lock is held. */222 if (whence == SEEK_CUR)223 return vfs_setpos_cookie(file, file->f_pos + offset, maxsize, cookie);224 225 return vfs_setpos_cookie(file, offset, maxsize, cookie);226}227EXPORT_SYMBOL(generic_llseek_cookie);228 229/**230 * generic_file_llseek - generic llseek implementation for regular files231 * @file: file structure to seek on232 * @offset: file offset to seek to233 * @whence: type of seek234 *235 * This is a generic implemenation of ->llseek useable for all normal local236 * filesystems. It just updates the file offset to the value specified by237 * @offset and @whence.238 */239loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)240{241 struct inode *inode = file->f_mapping->host;242 243 return generic_file_llseek_size(file, offset, whence,244 inode->i_sb->s_maxbytes,245 i_size_read(inode));246}247EXPORT_SYMBOL(generic_file_llseek);248 249/**250 * fixed_size_llseek - llseek implementation for fixed-sized devices251 * @file: file structure to seek on252 * @offset: file offset to seek to253 * @whence: type of seek254 * @size: size of the file255 *256 */257loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)258{259 switch (whence) {260 case SEEK_SET: case SEEK_CUR: case SEEK_END:261 return generic_file_llseek_size(file, offset, whence,262 size, size);263 default:264 return -EINVAL;265 }266}267EXPORT_SYMBOL(fixed_size_llseek);268 269/**270 * no_seek_end_llseek - llseek implementation for fixed-sized devices271 * @file: file structure to seek on272 * @offset: file offset to seek to273 * @whence: type of seek274 *275 */276loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)277{278 switch (whence) {279 case SEEK_SET: case SEEK_CUR:280 return generic_file_llseek_size(file, offset, whence,281 OFFSET_MAX, 0);282 default:283 return -EINVAL;284 }285}286EXPORT_SYMBOL(no_seek_end_llseek);287 288/**289 * no_seek_end_llseek_size - llseek implementation for fixed-sized devices290 * @file: file structure to seek on291 * @offset: file offset to seek to292 * @whence: type of seek293 * @size: maximal offset allowed294 *295 */296loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size)297{298 switch (whence) {299 case SEEK_SET: case SEEK_CUR:300 return generic_file_llseek_size(file, offset, whence,301 size, 0);302 default:303 return -EINVAL;304 }305}306EXPORT_SYMBOL(no_seek_end_llseek_size);307 308/**309 * noop_llseek - No Operation Performed llseek implementation310 * @file: file structure to seek on311 * @offset: file offset to seek to312 * @whence: type of seek313 *314 * This is an implementation of ->llseek useable for the rare special case when315 * userspace expects the seek to succeed but the (device) file is actually not316 * able to perform the seek. In this case you use noop_llseek() instead of317 * falling back to the default implementation of ->llseek.318 */319loff_t noop_llseek(struct file *file, loff_t offset, int whence)320{321 return file->f_pos;322}323EXPORT_SYMBOL(noop_llseek);324 325loff_t default_llseek(struct file *file, loff_t offset, int whence)326{327 struct inode *inode = file_inode(file);328 loff_t retval;329 330 inode_lock(inode);331 switch (whence) {332 case SEEK_END:333 offset += i_size_read(inode);334 break;335 case SEEK_CUR:336 if (offset == 0) {337 retval = file->f_pos;338 goto out;339 }340 offset += file->f_pos;341 break;342 case SEEK_DATA:343 /*344 * In the generic case the entire file is data, so as345 * long as offset isn't at the end of the file then the346 * offset is data.347 */348 if (offset >= inode->i_size) {349 retval = -ENXIO;350 goto out;351 }352 break;353 case SEEK_HOLE:354 /*355 * There is a virtual hole at the end of the file, so356 * as long as offset isn't i_size or larger, return357 * i_size.358 */359 if (offset >= inode->i_size) {360 retval = -ENXIO;361 goto out;362 }363 offset = inode->i_size;364 break;365 }366 retval = -EINVAL;367 if (offset >= 0 || unsigned_offsets(file)) {368 if (offset != file->f_pos)369 file->f_pos = offset;370 retval = offset;371 }372out:373 inode_unlock(inode);374 return retval;375}376EXPORT_SYMBOL(default_llseek);377 378loff_t vfs_llseek(struct file *file, loff_t offset, int whence)379{380 if (!(file->f_mode & FMODE_LSEEK))381 return -ESPIPE;382 return file->f_op->llseek(file, offset, whence);383}384EXPORT_SYMBOL(vfs_llseek);385 386static off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence)387{388 off_t retval;389 struct fd f = fdget_pos(fd);390 if (!fd_file(f))391 return -EBADF;392 393 retval = -EINVAL;394 if (whence <= SEEK_MAX) {395 loff_t res = vfs_llseek(fd_file(f), offset, whence);396 retval = res;397 if (res != (loff_t)retval)398 retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */399 }400 fdput_pos(f);401 return retval;402}403 404SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)405{406 return ksys_lseek(fd, offset, whence);407}408 409#ifdef CONFIG_COMPAT410COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)411{412 return ksys_lseek(fd, offset, whence);413}414#endif415 416#if !defined(CONFIG_64BIT) || defined(CONFIG_COMPAT) || \417 defined(__ARCH_WANT_SYS_LLSEEK)418SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,419 unsigned long, offset_low, loff_t __user *, result,420 unsigned int, whence)421{422 int retval;423 struct fd f = fdget_pos(fd);424 loff_t offset;425 426 if (!fd_file(f))427 return -EBADF;428 429 retval = -EINVAL;430 if (whence > SEEK_MAX)431 goto out_putf;432 433 offset = vfs_llseek(fd_file(f), ((loff_t) offset_high << 32) | offset_low,434 whence);435 436 retval = (int)offset;437 if (offset >= 0) {438 retval = -EFAULT;439 if (!copy_to_user(result, &offset, sizeof(offset)))440 retval = 0;441 }442out_putf:443 fdput_pos(f);444 return retval;445}446#endif447 448int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)449{450 int mask = read_write == READ ? MAY_READ : MAY_WRITE;451 int ret;452 453 if (unlikely((ssize_t) count < 0))454 return -EINVAL;455 456 if (ppos) {457 loff_t pos = *ppos;458 459 if (unlikely(pos < 0)) {460 if (!unsigned_offsets(file))461 return -EINVAL;462 if (count >= -pos) /* both values are in 0..LLONG_MAX */463 return -EOVERFLOW;464 } else if (unlikely((loff_t) (pos + count) < 0)) {465 if (!unsigned_offsets(file))466 return -EINVAL;467 }468 }469 470 ret = security_file_permission(file, mask);471 if (ret)472 return ret;473 474 return fsnotify_file_area_perm(file, mask, ppos, count);475}476EXPORT_SYMBOL(rw_verify_area);477 478static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)479{480 struct kiocb kiocb;481 struct iov_iter iter;482 ssize_t ret;483 484 init_sync_kiocb(&kiocb, filp);485 kiocb.ki_pos = (ppos ? *ppos : 0);486 iov_iter_ubuf(&iter, ITER_DEST, buf, len);487 488 ret = filp->f_op->read_iter(&kiocb, &iter);489 BUG_ON(ret == -EIOCBQUEUED);490 if (ppos)491 *ppos = kiocb.ki_pos;492 return ret;493}494 495static int warn_unsupported(struct file *file, const char *op)496{497 pr_warn_ratelimited(498 "kernel %s not supported for file %pD4 (pid: %d comm: %.20s)\n",499 op, file, current->pid, current->comm);500 return -EINVAL;501}502 503ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)504{505 struct kvec iov = {506 .iov_base = buf,507 .iov_len = min_t(size_t, count, MAX_RW_COUNT),508 };509 struct kiocb kiocb;510 struct iov_iter iter;511 ssize_t ret;512 513 if (WARN_ON_ONCE(!(file->f_mode & FMODE_READ)))514 return -EINVAL;515 if (!(file->f_mode & FMODE_CAN_READ))516 return -EINVAL;517 /*518 * Also fail if ->read_iter and ->read are both wired up as that519 * implies very convoluted semantics.520 */521 if (unlikely(!file->f_op->read_iter || file->f_op->read))522 return warn_unsupported(file, "read");523 524 init_sync_kiocb(&kiocb, file);525 kiocb.ki_pos = pos ? *pos : 0;526 iov_iter_kvec(&iter, ITER_DEST, &iov, 1, iov.iov_len);527 ret = file->f_op->read_iter(&kiocb, &iter);528 if (ret > 0) {529 if (pos)530 *pos = kiocb.ki_pos;531 fsnotify_access(file);532 add_rchar(current, ret);533 }534 inc_syscr(current);535 return ret;536}537 538ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)539{540 ssize_t ret;541 542 ret = rw_verify_area(READ, file, pos, count);543 if (ret)544 return ret;545 return __kernel_read(file, buf, count, pos);546}547EXPORT_SYMBOL(kernel_read);548 549ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)550{551 ssize_t ret;552 553 if (!(file->f_mode & FMODE_READ))554 return -EBADF;555 if (!(file->f_mode & FMODE_CAN_READ))556 return -EINVAL;557 if (unlikely(!access_ok(buf, count)))558 return -EFAULT;559 560 ret = rw_verify_area(READ, file, pos, count);561 if (ret)562 return ret;563 if (count > MAX_RW_COUNT)564 count = MAX_RW_COUNT;565 566 if (file->f_op->read)567 ret = file->f_op->read(file, buf, count, pos);568 else if (file->f_op->read_iter)569 ret = new_sync_read(file, buf, count, pos);570 else571 ret = -EINVAL;572 if (ret > 0) {573 fsnotify_access(file);574 add_rchar(current, ret);575 }576 inc_syscr(current);577 return ret;578}579 580static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)581{582 struct kiocb kiocb;583 struct iov_iter iter;584 ssize_t ret;585 586 init_sync_kiocb(&kiocb, filp);587 kiocb.ki_pos = (ppos ? *ppos : 0);588 iov_iter_ubuf(&iter, ITER_SOURCE, (void __user *)buf, len);589 590 ret = filp->f_op->write_iter(&kiocb, &iter);591 BUG_ON(ret == -EIOCBQUEUED);592 if (ret > 0 && ppos)593 *ppos = kiocb.ki_pos;594 return ret;595}596 597/* caller is responsible for file_start_write/file_end_write */598ssize_t __kernel_write_iter(struct file *file, struct iov_iter *from, loff_t *pos)599{600 struct kiocb kiocb;601 ssize_t ret;602 603 if (WARN_ON_ONCE(!(file->f_mode & FMODE_WRITE)))604 return -EBADF;605 if (!(file->f_mode & FMODE_CAN_WRITE))606 return -EINVAL;607 /*608 * Also fail if ->write_iter and ->write are both wired up as that609 * implies very convoluted semantics.610 */611 if (unlikely(!file->f_op->write_iter || file->f_op->write))612 return warn_unsupported(file, "write");613 614 init_sync_kiocb(&kiocb, file);615 kiocb.ki_pos = pos ? *pos : 0;616 ret = file->f_op->write_iter(&kiocb, from);617 if (ret > 0) {618 if (pos)619 *pos = kiocb.ki_pos;620 fsnotify_modify(file);621 add_wchar(current, ret);622 }623 inc_syscw(current);624 return ret;625}626 627/* caller is responsible for file_start_write/file_end_write */628ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)629{630 struct kvec iov = {631 .iov_base = (void *)buf,632 .iov_len = min_t(size_t, count, MAX_RW_COUNT),633 };634 struct iov_iter iter;635 iov_iter_kvec(&iter, ITER_SOURCE, &iov, 1, iov.iov_len);636 return __kernel_write_iter(file, &iter, pos);637}638/*639 * This "EXPORT_SYMBOL_GPL()" is more of a "EXPORT_SYMBOL_DONTUSE()",640 * but autofs is one of the few internal kernel users that actually641 * wants this _and_ can be built as a module. So we need to export642 * this symbol for autofs, even though it really isn't appropriate643 * for any other kernel modules.644 */645EXPORT_SYMBOL_GPL(__kernel_write);646 647ssize_t kernel_write(struct file *file, const void *buf, size_t count,648 loff_t *pos)649{650 ssize_t ret;651 652 ret = rw_verify_area(WRITE, file, pos, count);653 if (ret)654 return ret;655 656 file_start_write(file);657 ret = __kernel_write(file, buf, count, pos);658 file_end_write(file);659 return ret;660}661EXPORT_SYMBOL(kernel_write);662 663ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)664{665 ssize_t ret;666 667 if (!(file->f_mode & FMODE_WRITE))668 return -EBADF;669 if (!(file->f_mode & FMODE_CAN_WRITE))670 return -EINVAL;671 if (unlikely(!access_ok(buf, count)))672 return -EFAULT;673 674 ret = rw_verify_area(WRITE, file, pos, count);675 if (ret)676 return ret;677 if (count > MAX_RW_COUNT)678 count = MAX_RW_COUNT;679 file_start_write(file);680 if (file->f_op->write)681 ret = file->f_op->write(file, buf, count, pos);682 else if (file->f_op->write_iter)683 ret = new_sync_write(file, buf, count, pos);684 else685 ret = -EINVAL;686 if (ret > 0) {687 fsnotify_modify(file);688 add_wchar(current, ret);689 }690 inc_syscw(current);691 file_end_write(file);692 return ret;693}694 695/* file_ppos returns &file->f_pos or NULL if file is stream */696static inline loff_t *file_ppos(struct file *file)697{698 return file->f_mode & FMODE_STREAM ? NULL : &file->f_pos;699}700 701ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)702{703 struct fd f = fdget_pos(fd);704 ssize_t ret = -EBADF;705 706 if (fd_file(f)) {707 loff_t pos, *ppos = file_ppos(fd_file(f));708 if (ppos) {709 pos = *ppos;710 ppos = &pos;711 }712 ret = vfs_read(fd_file(f), buf, count, ppos);713 if (ret >= 0 && ppos)714 fd_file(f)->f_pos = pos;715 fdput_pos(f);716 }717 return ret;718}719 720SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)721{722 return ksys_read(fd, buf, count);723}724 725ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)726{727 struct fd f = fdget_pos(fd);728 ssize_t ret = -EBADF;729 730 if (fd_file(f)) {731 loff_t pos, *ppos = file_ppos(fd_file(f));732 if (ppos) {733 pos = *ppos;734 ppos = &pos;735 }736 ret = vfs_write(fd_file(f), buf, count, ppos);737 if (ret >= 0 && ppos)738 fd_file(f)->f_pos = pos;739 fdput_pos(f);740 }741 742 return ret;743}744 745SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,746 size_t, count)747{748 return ksys_write(fd, buf, count);749}750 751ssize_t ksys_pread64(unsigned int fd, char __user *buf, size_t count,752 loff_t pos)753{754 struct fd f;755 ssize_t ret = -EBADF;756 757 if (pos < 0)758 return -EINVAL;759 760 f = fdget(fd);761 if (fd_file(f)) {762 ret = -ESPIPE;763 if (fd_file(f)->f_mode & FMODE_PREAD)764 ret = vfs_read(fd_file(f), buf, count, &pos);765 fdput(f);766 }767 768 return ret;769}770 771SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,772 size_t, count, loff_t, pos)773{774 return ksys_pread64(fd, buf, count, pos);775}776 777#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PREAD64)778COMPAT_SYSCALL_DEFINE5(pread64, unsigned int, fd, char __user *, buf,779 size_t, count, compat_arg_u64_dual(pos))780{781 return ksys_pread64(fd, buf, count, compat_arg_u64_glue(pos));782}783#endif784 785ssize_t ksys_pwrite64(unsigned int fd, const char __user *buf,786 size_t count, loff_t pos)787{788 struct fd f;789 ssize_t ret = -EBADF;790 791 if (pos < 0)792 return -EINVAL;793 794 f = fdget(fd);795 if (fd_file(f)) {796 ret = -ESPIPE;797 if (fd_file(f)->f_mode & FMODE_PWRITE)798 ret = vfs_write(fd_file(f), buf, count, &pos);799 fdput(f);800 }801 802 return ret;803}804 805SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,806 size_t, count, loff_t, pos)807{808 return ksys_pwrite64(fd, buf, count, pos);809}810 811#if defined(CONFIG_COMPAT) && defined(__ARCH_WANT_COMPAT_PWRITE64)812COMPAT_SYSCALL_DEFINE5(pwrite64, unsigned int, fd, const char __user *, buf,813 size_t, count, compat_arg_u64_dual(pos))814{815 return ksys_pwrite64(fd, buf, count, compat_arg_u64_glue(pos));816}817#endif818 819static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,820 loff_t *ppos, int type, rwf_t flags)821{822 struct kiocb kiocb;823 ssize_t ret;824 825 init_sync_kiocb(&kiocb, filp);826 ret = kiocb_set_rw_flags(&kiocb, flags, type);827 if (ret)828 return ret;829 kiocb.ki_pos = (ppos ? *ppos : 0);830 831 if (type == READ)832 ret = filp->f_op->read_iter(&kiocb, iter);833 else834 ret = filp->f_op->write_iter(&kiocb, iter);835 BUG_ON(ret == -EIOCBQUEUED);836 if (ppos)837 *ppos = kiocb.ki_pos;838 return ret;839}840 841/* Do it by hand, with file-ops */842static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,843 loff_t *ppos, int type, rwf_t flags)844{845 ssize_t ret = 0;846 847 if (flags & ~RWF_HIPRI)848 return -EOPNOTSUPP;849 850 while (iov_iter_count(iter)) {851 ssize_t nr;852 853 if (type == READ) {854 nr = filp->f_op->read(filp, iter_iov_addr(iter),855 iter_iov_len(iter), ppos);856 } else {857 nr = filp->f_op->write(filp, iter_iov_addr(iter),858 iter_iov_len(iter), ppos);859 }860 861 if (nr < 0) {862 if (!ret)863 ret = nr;864 break;865 }866 ret += nr;867 if (nr != iter_iov_len(iter))868 break;869 iov_iter_advance(iter, nr);870 }871 872 return ret;873}874 875ssize_t vfs_iocb_iter_read(struct file *file, struct kiocb *iocb,876 struct iov_iter *iter)877{878 size_t tot_len;879 ssize_t ret = 0;880 881 if (!file->f_op->read_iter)882 return -EINVAL;883 if (!(file->f_mode & FMODE_READ))884 return -EBADF;885 if (!(file->f_mode & FMODE_CAN_READ))886 return -EINVAL;887 888 tot_len = iov_iter_count(iter);889 if (!tot_len)890 goto out;891 ret = rw_verify_area(READ, file, &iocb->ki_pos, tot_len);892 if (ret < 0)893 return ret;894 895 ret = file->f_op->read_iter(iocb, iter);896out:897 if (ret >= 0)898 fsnotify_access(file);899 return ret;900}901EXPORT_SYMBOL(vfs_iocb_iter_read);902 903ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,904 rwf_t flags)905{906 size_t tot_len;907 ssize_t ret = 0;908 909 if (!file->f_op->read_iter)910 return -EINVAL;911 if (!(file->f_mode & FMODE_READ))912 return -EBADF;913 if (!(file->f_mode & FMODE_CAN_READ))914 return -EINVAL;915 916 tot_len = iov_iter_count(iter);917 if (!tot_len)918 goto out;919 ret = rw_verify_area(READ, file, ppos, tot_len);920 if (ret < 0)921 return ret;922 923 ret = do_iter_readv_writev(file, iter, ppos, READ, flags);924out:925 if (ret >= 0)926 fsnotify_access(file);927 return ret;928}929EXPORT_SYMBOL(vfs_iter_read);930 931/*932 * Caller is responsible for calling kiocb_end_write() on completion933 * if async iocb was queued.934 */935ssize_t vfs_iocb_iter_write(struct file *file, struct kiocb *iocb,936 struct iov_iter *iter)937{938 size_t tot_len;939 ssize_t ret = 0;940 941 if (!file->f_op->write_iter)942 return -EINVAL;943 if (!(file->f_mode & FMODE_WRITE))944 return -EBADF;945 if (!(file->f_mode & FMODE_CAN_WRITE))946 return -EINVAL;947 948 tot_len = iov_iter_count(iter);949 if (!tot_len)950 return 0;951 ret = rw_verify_area(WRITE, file, &iocb->ki_pos, tot_len);952 if (ret < 0)953 return ret;954 955 kiocb_start_write(iocb);956 ret = file->f_op->write_iter(iocb, iter);957 if (ret != -EIOCBQUEUED)958 kiocb_end_write(iocb);959 if (ret > 0)960 fsnotify_modify(file);961 962 return ret;963}964EXPORT_SYMBOL(vfs_iocb_iter_write);965 966ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,967 rwf_t flags)968{969 size_t tot_len;970 ssize_t ret;971 972 if (!(file->f_mode & FMODE_WRITE))973 return -EBADF;974 if (!(file->f_mode & FMODE_CAN_WRITE))975 return -EINVAL;976 if (!file->f_op->write_iter)977 return -EINVAL;978 979 tot_len = iov_iter_count(iter);980 if (!tot_len)981 return 0;982 983 ret = rw_verify_area(WRITE, file, ppos, tot_len);984 if (ret < 0)985 return ret;986 987 file_start_write(file);988 ret = do_iter_readv_writev(file, iter, ppos, WRITE, flags);989 if (ret > 0)990 fsnotify_modify(file);991 file_end_write(file);992 993 return ret;994}995EXPORT_SYMBOL(vfs_iter_write);996 997static ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,998 unsigned long vlen, loff_t *pos, rwf_t flags)999{1000 struct iovec iovstack[UIO_FASTIOV];1001 struct iovec *iov = iovstack;1002 struct iov_iter iter;1003 size_t tot_len;1004 ssize_t ret = 0;1005 1006 if (!(file->f_mode & FMODE_READ))1007 return -EBADF;1008 if (!(file->f_mode & FMODE_CAN_READ))1009 return -EINVAL;1010 1011 ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov,1012 &iter);1013 if (ret < 0)1014 return ret;1015 1016 tot_len = iov_iter_count(&iter);1017 if (!tot_len)1018 goto out;1019 1020 ret = rw_verify_area(READ, file, pos, tot_len);1021 if (ret < 0)1022 goto out;1023 1024 if (file->f_op->read_iter)1025 ret = do_iter_readv_writev(file, &iter, pos, READ, flags);1026 else1027 ret = do_loop_readv_writev(file, &iter, pos, READ, flags);1028out:1029 if (ret >= 0)1030 fsnotify_access(file);1031 kfree(iov);1032 return ret;1033}1034 1035static HWJS_SUSPENDS ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,1036 unsigned long vlen, loff_t *pos, rwf_t flags)1037{1038 struct iovec iovstack[UIO_FASTIOV];1039 struct iovec *iov = iovstack;1040 struct iov_iter iter;1041 size_t tot_len;1042 ssize_t ret = 0;1043 1044 if (!(file->f_mode & FMODE_WRITE))1045 return -EBADF;1046 if (!(file->f_mode & FMODE_CAN_WRITE))1047 return -EINVAL;1048 1049 ret = import_iovec(ITER_SOURCE, vec, vlen, ARRAY_SIZE(iovstack), &iov,1050 &iter);1051 if (ret < 0)1052 return ret;1053 1054 tot_len = iov_iter_count(&iter);1055 if (!tot_len)1056 goto out;1057 1058 ret = rw_verify_area(WRITE, file, pos, tot_len);1059 if (ret < 0)1060 goto out;1061 1062 file_start_write(file);1063 if (file->f_op->write_iter)1064 ret = do_iter_readv_writev(file, &iter, pos, WRITE, flags);1065 else1066 ret = do_loop_readv_writev(file, &iter, pos, WRITE, flags);1067 if (ret > 0)1068 fsnotify_modify(file);1069 file_end_write(file);1070out:1071 kfree(iov);1072 return ret;1073}1074 1075static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,1076 unsigned long vlen, rwf_t flags)1077{1078 struct fd f = fdget_pos(fd);1079 ssize_t ret = -EBADF;1080 1081 if (fd_file(f)) {1082 loff_t pos, *ppos = file_ppos(fd_file(f));1083 if (ppos) {1084 pos = *ppos;1085 ppos = &pos;1086 }1087 ret = vfs_readv(fd_file(f), vec, vlen, ppos, flags);1088 if (ret >= 0 && ppos)1089 fd_file(f)->f_pos = pos;1090 fdput_pos(f);1091 }1092 1093 if (ret > 0)1094 add_rchar(current, ret);1095 inc_syscr(current);1096 return ret;1097}1098 1099static HWJS_SUSPENDS ssize_t do_writev(unsigned long fd, const struct iovec __user *vec,1100 unsigned long vlen, rwf_t flags)1101{1102 struct fd f = fdget_pos(fd);1103 ssize_t ret = -EBADF;1104 1105 if (fd_file(f)) {1106 loff_t pos, *ppos = file_ppos(fd_file(f));1107 if (ppos) {1108 pos = *ppos;1109 ppos = &pos;1110 }1111 ret = vfs_writev(fd_file(f), vec, vlen, ppos, flags);1112 if (ret >= 0 && ppos)1113 fd_file(f)->f_pos = pos;1114 fdput_pos(f);1115 }1116 1117 if (ret > 0)1118 add_wchar(current, ret);1119 inc_syscw(current);1120 return ret;1121}1122 1123static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)1124{1125#define HALF_LONG_BITS (BITS_PER_LONG / 2)1126 return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;1127}1128 1129static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec,1130 unsigned long vlen, loff_t pos, rwf_t flags)1131{1132 struct fd f;1133 ssize_t ret = -EBADF;1134 1135 if (pos < 0)1136 return -EINVAL;1137 1138 f = fdget(fd);1139 if (fd_file(f)) {1140 ret = -ESPIPE;1141 if (fd_file(f)->f_mode & FMODE_PREAD)1142 ret = vfs_readv(fd_file(f), vec, vlen, &pos, flags);1143 fdput(f);1144 }1145 1146 if (ret > 0)1147 add_rchar(current, ret);1148 inc_syscr(current);1149 return ret;1150}1151 1152static HWJS_SUSPENDS ssize_t do_pwritev(unsigned long fd, const struct iovec __user *vec,1153 unsigned long vlen, loff_t pos, rwf_t flags)1154{1155 struct fd f;1156 ssize_t ret = -EBADF;1157 1158 if (pos < 0)1159 return -EINVAL;1160 1161 f = fdget(fd);1162 if (fd_file(f)) {1163 ret = -ESPIPE;1164 if (fd_file(f)->f_mode & FMODE_PWRITE)1165 ret = vfs_writev(fd_file(f), vec, vlen, &pos, flags);1166 fdput(f);1167 }1168 1169 if (ret > 0)1170 add_wchar(current, ret);1171 inc_syscw(current);1172 return ret;1173}1174 1175SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,1176 unsigned long, vlen)1177{1178 return do_readv(fd, vec, vlen, 0);1179}1180 1181SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,1182 unsigned long, vlen)1183{1184 return do_writev(fd, vec, vlen, 0);1185}1186 1187SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,1188 unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)1189{1190 loff_t pos = pos_from_hilo(pos_h, pos_l);1191 1192 return do_preadv(fd, vec, vlen, pos, 0);1193}1194 1195SYSCALL_DEFINE6(preadv2, unsigned long, fd, const struct iovec __user *, vec,1196 unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,1197 rwf_t, flags)1198{1199 loff_t pos = pos_from_hilo(pos_h, pos_l);1200 1201 if (pos == -1)1202 return do_readv(fd, vec, vlen, flags);1203 1204 return do_preadv(fd, vec, vlen, pos, flags);1205}1206 1207SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,1208 unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)1209{1210 loff_t pos = pos_from_hilo(pos_h, pos_l);1211 1212 return do_pwritev(fd, vec, vlen, pos, 0);1213}1214 1215SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec,1216 unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,1217 rwf_t, flags)1218{1219 loff_t pos = pos_from_hilo(pos_h, pos_l);1220 1221 if (pos == -1)1222 return do_writev(fd, vec, vlen, flags);1223 1224 return do_pwritev(fd, vec, vlen, pos, flags);1225}1226 1227/*1228 * Various compat syscalls. Note that they all pretend to take a native1229 * iovec - import_iovec will properly treat those as compat_iovecs based on1230 * in_compat_syscall().1231 */1232#ifdef CONFIG_COMPAT1233#ifdef __ARCH_WANT_COMPAT_SYS_PREADV641234COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,1235 const struct iovec __user *, vec,1236 unsigned long, vlen, loff_t, pos)1237{1238 return do_preadv(fd, vec, vlen, pos, 0);1239}1240#endif1241 1242COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,1243 const struct iovec __user *, vec,1244 compat_ulong_t, vlen, u32, pos_low, u32, pos_high)1245{1246 loff_t pos = ((loff_t)pos_high << 32) | pos_low;1247 1248 return do_preadv(fd, vec, vlen, pos, 0);1249}1250 1251#ifdef __ARCH_WANT_COMPAT_SYS_PREADV64V21252COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,1253 const struct iovec __user *, vec,1254 unsigned long, vlen, loff_t, pos, rwf_t, flags)1255{1256 if (pos == -1)1257 return do_readv(fd, vec, vlen, flags);1258 return do_preadv(fd, vec, vlen, pos, flags);1259}1260#endif1261 1262COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd,1263 const struct iovec __user *, vec,1264 compat_ulong_t, vlen, u32, pos_low, u32, pos_high,1265 rwf_t, flags)1266{1267 loff_t pos = ((loff_t)pos_high << 32) | pos_low;1268 1269 if (pos == -1)1270 return do_readv(fd, vec, vlen, flags);1271 return do_preadv(fd, vec, vlen, pos, flags);1272}1273 1274#ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV641275COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,1276 const struct iovec __user *, vec,1277 unsigned long, vlen, loff_t, pos)1278{1279 return do_pwritev(fd, vec, vlen, pos, 0);1280}1281#endif1282 1283COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,1284 const struct iovec __user *,vec,1285 compat_ulong_t, vlen, u32, pos_low, u32, pos_high)1286{1287 loff_t pos = ((loff_t)pos_high << 32) | pos_low;1288 1289 return do_pwritev(fd, vec, vlen, pos, 0);1290}1291 1292#ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64V21293COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,1294 const struct iovec __user *, vec,1295 unsigned long, vlen, loff_t, pos, rwf_t, flags)1296{1297 if (pos == -1)1298 return do_writev(fd, vec, vlen, flags);1299 return do_pwritev(fd, vec, vlen, pos, flags);1300}1301#endif1302 1303COMPAT_SYSCALL_DEFINE6(pwritev2, compat_ulong_t, fd,1304 const struct iovec __user *,vec,1305 compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags)1306{1307 loff_t pos = ((loff_t)pos_high << 32) | pos_low;1308 1309 if (pos == -1)1310 return do_writev(fd, vec, vlen, flags);1311 return do_pwritev(fd, vec, vlen, pos, flags);1312}1313#endif /* CONFIG_COMPAT */1314 1315static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,1316 size_t count, loff_t max)1317{1318 struct fd in, out;1319 struct inode *in_inode, *out_inode;1320 struct pipe_inode_info *opipe;1321 loff_t pos;1322 loff_t out_pos;1323 ssize_t retval;1324 int fl;1325 1326 /*1327 * Get input file, and verify that it is ok..1328 */1329 retval = -EBADF;1330 in = fdget(in_fd);1331 if (!fd_file(in))1332 goto out;1333 if (!(fd_file(in)->f_mode & FMODE_READ))1334 goto fput_in;1335 retval = -ESPIPE;1336 if (!ppos) {1337 pos = fd_file(in)->f_pos;1338 } else {1339 pos = *ppos;1340 if (!(fd_file(in)->f_mode & FMODE_PREAD))1341 goto fput_in;1342 }1343 retval = rw_verify_area(READ, fd_file(in), &pos, count);1344 if (retval < 0)1345 goto fput_in;1346 if (count > MAX_RW_COUNT)1347 count = MAX_RW_COUNT;1348 1349 /*1350 * Get output file, and verify that it is ok..1351 */1352 retval = -EBADF;1353 out = fdget(out_fd);1354 if (!fd_file(out))1355 goto fput_in;1356 if (!(fd_file(out)->f_mode & FMODE_WRITE))1357 goto fput_out;1358 in_inode = file_inode(fd_file(in));1359 out_inode = file_inode(fd_file(out));1360 out_pos = fd_file(out)->f_pos;1361 1362 if (!max)1363 max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);1364 1365 if (unlikely(pos + count > max)) {1366 retval = -EOVERFLOW;1367 if (pos >= max)1368 goto fput_out;1369 count = max - pos;1370 }1371 1372 fl = 0;1373#if 01374 /*1375 * We need to debate whether we can enable this or not. The1376 * man page documents EAGAIN return for the output at least,1377 * and the application is arguably buggy if it doesn't expect1378 * EAGAIN on a non-blocking file descriptor.1379 */1380 if (fd_file(in)->f_flags & O_NONBLOCK)1381 fl = SPLICE_F_NONBLOCK;1382#endif1383 opipe = get_pipe_info(fd_file(out), true);1384 if (!opipe) {1385 retval = rw_verify_area(WRITE, fd_file(out), &out_pos, count);1386 if (retval < 0)1387 goto fput_out;1388 retval = do_splice_direct(fd_file(in), &pos, fd_file(out), &out_pos,1389 count, fl);1390 } else {1391 if (fd_file(out)->f_flags & O_NONBLOCK)1392 fl |= SPLICE_F_NONBLOCK;1393 1394 retval = splice_file_to_pipe(fd_file(in), opipe, &pos, count, fl);1395 }1396 1397 if (retval > 0) {1398 add_rchar(current, retval);1399 add_wchar(current, retval);1400 fsnotify_access(fd_file(in));1401 fsnotify_modify(fd_file(out));1402 fd_file(out)->f_pos = out_pos;1403 if (ppos)1404 *ppos = pos;1405 else1406 fd_file(in)->f_pos = pos;1407 }1408 1409 inc_syscr(current);1410 inc_syscw(current);1411 if (pos > max)1412 retval = -EOVERFLOW;1413 1414fput_out:1415 fdput(out);1416fput_in:1417 fdput(in);1418out:1419 return retval;1420}1421 1422SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)1423{1424 loff_t pos;1425 off_t off;1426 ssize_t ret;1427 1428 if (offset) {1429 if (unlikely(get_user(off, offset)))1430 return -EFAULT;1431 pos = off;1432 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);1433 if (unlikely(put_user(pos, offset)))1434 return -EFAULT;1435 return ret;1436 }1437 1438 return do_sendfile(out_fd, in_fd, NULL, count, 0);1439}1440 1441SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)1442{1443 loff_t pos;1444 ssize_t ret;1445 1446 if (offset) {1447 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))1448 return -EFAULT;1449 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);1450 if (unlikely(put_user(pos, offset)))1451 return -EFAULT;1452 return ret;1453 }1454 1455 return do_sendfile(out_fd, in_fd, NULL, count, 0);1456}1457 1458#ifdef CONFIG_COMPAT1459COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd,1460 compat_off_t __user *, offset, compat_size_t, count)1461{1462 loff_t pos;1463 off_t off;1464 ssize_t ret;1465 1466 if (offset) {1467 if (unlikely(get_user(off, offset)))1468 return -EFAULT;1469 pos = off;1470 ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);1471 if (unlikely(put_user(pos, offset)))1472 return -EFAULT;1473 return ret;1474 }1475 1476 return do_sendfile(out_fd, in_fd, NULL, count, 0);1477}1478 1479COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,1480 compat_loff_t __user *, offset, compat_size_t, count)1481{1482 loff_t pos;1483 ssize_t ret;1484 1485 if (offset) {1486 if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))1487 return -EFAULT;1488 ret = do_sendfile(out_fd, in_fd, &pos, count, 0);1489 if (unlikely(put_user(pos, offset)))1490 return -EFAULT;1491 return ret;1492 }1493 1494 return do_sendfile(out_fd, in_fd, NULL, count, 0);1495}1496#endif1497 1498/*1499 * Performs necessary checks before doing a file copy1500 *1501 * Can adjust amount of bytes to copy via @req_count argument.1502 * Returns appropriate error code that caller should return or1503 * zero in case the copy should be allowed.1504 */1505static int generic_copy_file_checks(struct file *file_in, loff_t pos_in,1506 struct file *file_out, loff_t pos_out,1507 size_t *req_count, unsigned int flags)1508{1509 struct inode *inode_in = file_inode(file_in);1510 struct inode *inode_out = file_inode(file_out);1511 uint64_t count = *req_count;1512 loff_t size_in;1513 int ret;1514 1515 ret = generic_file_rw_checks(file_in, file_out);1516 if (ret)1517 return ret;1518 1519 /*1520 * We allow some filesystems to handle cross sb copy, but passing1521 * a file of the wrong filesystem type to filesystem driver can result1522 * in an attempt to dereference the wrong type of ->private_data, so1523 * avoid doing that until we really have a good reason.1524 *1525 * nfs and cifs define several different file_system_type structures1526 * and several different sets of file_operations, but they all end up1527 * using the same ->copy_file_range() function pointer.1528 */1529 if (flags & COPY_FILE_SPLICE) {1530 /* cross sb splice is allowed */1531 } else if (file_out->f_op->copy_file_range) {1532 if (file_in->f_op->copy_file_range !=1533 file_out->f_op->copy_file_range)1534 return -EXDEV;1535 } else if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb) {1536 return -EXDEV;1537 }1538 1539 /* Don't touch certain kinds of inodes */1540 if (IS_IMMUTABLE(inode_out))1541 return -EPERM;1542 1543 if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))1544 return -ETXTBSY;1545 1546 /* Ensure offsets don't wrap. */1547 if (pos_in + count < pos_in || pos_out + count < pos_out)1548 return -EOVERFLOW;1549 1550 /* Shorten the copy to EOF */1551 size_in = i_size_read(inode_in);1552 if (pos_in >= size_in)1553 count = 0;1554 else1555 count = min(count, size_in - (uint64_t)pos_in);1556 1557 ret = generic_write_check_limits(file_out, pos_out, &count);1558 if (ret)1559 return ret;1560 1561 /* Don't allow overlapped copying within the same file. */1562 if (inode_in == inode_out &&1563 pos_out + count > pos_in &&1564 pos_out < pos_in + count)1565 return -EINVAL;1566 1567 *req_count = count;1568 return 0;1569}1570 1571/*1572 * copy_file_range() differs from regular file read and write in that it1573 * specifically allows return partial success. When it does so is up to1574 * the copy_file_range method.1575 */1576ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,1577 struct file *file_out, loff_t pos_out,1578 size_t len, unsigned int flags)1579{1580 ssize_t ret;1581 bool splice = flags & COPY_FILE_SPLICE;1582 bool samesb = file_inode(file_in)->i_sb == file_inode(file_out)->i_sb;1583 1584 if (flags & ~COPY_FILE_SPLICE)1585 return -EINVAL;1586 1587 ret = generic_copy_file_checks(file_in, pos_in, file_out, pos_out, &len,1588 flags);1589 if (unlikely(ret))1590 return ret;1591 1592 ret = rw_verify_area(READ, file_in, &pos_in, len);1593 if (unlikely(ret))1594 return ret;1595 1596 ret = rw_verify_area(WRITE, file_out, &pos_out, len);1597 if (unlikely(ret))1598 return ret;1599 1600 if (len == 0)1601 return 0;1602 1603 file_start_write(file_out);1604 1605 /*1606 * Cloning is supported by more file systems, so we implement copy on1607 * same sb using clone, but for filesystems where both clone and copy1608 * are supported (e.g. nfs,cifs), we only call the copy method.1609 */1610 if (!splice && file_out->f_op->copy_file_range) {1611 ret = file_out->f_op->copy_file_range(file_in, pos_in,1612 file_out, pos_out,1613 len, flags);1614 } else if (!splice && file_in->f_op->remap_file_range && samesb) {1615 ret = file_in->f_op->remap_file_range(file_in, pos_in,1616 file_out, pos_out,1617 min_t(loff_t, MAX_RW_COUNT, len),1618 REMAP_FILE_CAN_SHORTEN);1619 /* fallback to splice */1620 if (ret <= 0)1621 splice = true;1622 } else if (samesb) {1623 /* Fallback to splice for same sb copy for backward compat */1624 splice = true;1625 }1626 1627 file_end_write(file_out);1628 1629 if (!splice)1630 goto done;1631 1632 /*1633 * We can get here for same sb copy of filesystems that do not implement1634 * ->copy_file_range() in case filesystem does not support clone or in1635 * case filesystem supports clone but rejected the clone request (e.g.1636 * because it was not block aligned).1637 *1638 * In both cases, fall back to kernel copy so we are able to maintain a1639 * consistent story about which filesystems support copy_file_range()1640 * and which filesystems do not, that will allow userspace tools to1641 * make consistent desicions w.r.t using copy_file_range().1642 *1643 * We also get here if caller (e.g. nfsd) requested COPY_FILE_SPLICE1644 * for server-side-copy between any two sb.1645 *1646 * In any case, we call do_splice_direct() and not splice_file_range(),1647 * without file_start_write() held, to avoid possible deadlocks related1648 * to splicing from input file, while file_start_write() is held on1649 * the output file on a different sb.1650 */1651 ret = do_splice_direct(file_in, &pos_in, file_out, &pos_out,1652 min_t(size_t, len, MAX_RW_COUNT), 0);1653done:1654 if (ret > 0) {1655 fsnotify_access(file_in);1656 add_rchar(current, ret);1657 fsnotify_modify(file_out);1658 add_wchar(current, ret);1659 }1660 1661 inc_syscr(current);1662 inc_syscw(current);1663 1664 return ret;1665}1666EXPORT_SYMBOL(vfs_copy_file_range);1667 1668SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in,1669 int, fd_out, loff_t __user *, off_out,1670 size_t, len, unsigned int, flags)1671{1672 loff_t pos_in;1673 loff_t pos_out;1674 struct fd f_in;1675 struct fd f_out;1676 ssize_t ret = -EBADF;1677 1678 f_in = fdget(fd_in);1679 if (!fd_file(f_in))1680 goto out2;1681 1682 f_out = fdget(fd_out);1683 if (!fd_file(f_out))1684 goto out1;1685 1686 ret = -EFAULT;1687 if (off_in) {1688 if (copy_from_user(&pos_in, off_in, sizeof(loff_t)))1689 goto out;1690 } else {1691 pos_in = fd_file(f_in)->f_pos;1692 }1693 1694 if (off_out) {1695 if (copy_from_user(&pos_out, off_out, sizeof(loff_t)))1696 goto out;1697 } else {1698 pos_out = fd_file(f_out)->f_pos;1699 }1700 1701 ret = -EINVAL;1702 if (flags != 0)1703 goto out;1704 1705 ret = vfs_copy_file_range(fd_file(f_in), pos_in, fd_file(f_out), pos_out, len,1706 flags);1707 if (ret > 0) {1708 pos_in += ret;1709 pos_out += ret;1710 1711 if (off_in) {1712 if (copy_to_user(off_in, &pos_in, sizeof(loff_t)))1713 ret = -EFAULT;1714 } else {1715 fd_file(f_in)->f_pos = pos_in;1716 }1717 1718 if (off_out) {1719 if (copy_to_user(off_out, &pos_out, sizeof(loff_t)))1720 ret = -EFAULT;1721 } else {1722 fd_file(f_out)->f_pos = pos_out;1723 }1724 }1725 1726out:1727 fdput(f_out);1728out1:1729 fdput(f_in);1730out2:1731 return ret;1732}1733 1734/*1735 * Don't operate on ranges the page cache doesn't support, and don't exceed the1736 * LFS limits. If pos is under the limit it becomes a short access. If it1737 * exceeds the limit we return -EFBIG.1738 */1739int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)1740{1741 struct inode *inode = file->f_mapping->host;1742 loff_t max_size = inode->i_sb->s_maxbytes;1743 loff_t limit = rlimit(RLIMIT_FSIZE);1744 1745 if (limit != RLIM_INFINITY) {1746 if (pos >= limit) {1747 send_sig(SIGXFSZ, current, 0);1748 return -EFBIG;1749 }1750 *count = min(*count, limit - pos);1751 }1752 1753 if (!(file->f_flags & O_LARGEFILE))1754 max_size = MAX_NON_LFS;1755 1756 if (unlikely(pos >= max_size))1757 return -EFBIG;1758 1759 *count = min(*count, max_size - pos);1760 1761 return 0;1762}1763EXPORT_SYMBOL_GPL(generic_write_check_limits);1764 1765/* Like generic_write_checks(), but takes size of write instead of iter. */1766int generic_write_checks_count(struct kiocb *iocb, loff_t *count)1767{1768 struct file *file = iocb->ki_filp;1769 struct inode *inode = file->f_mapping->host;1770 1771 if (IS_SWAPFILE(inode))1772 return -ETXTBSY;1773 1774 if (!*count)1775 return 0;1776 1777 if (iocb->ki_flags & IOCB_APPEND)1778 iocb->ki_pos = i_size_read(inode);1779 1780 if ((iocb->ki_flags & IOCB_NOWAIT) &&1781 !((iocb->ki_flags & IOCB_DIRECT) ||1782 (file->f_op->fop_flags & FOP_BUFFER_WASYNC)))1783 return -EINVAL;1784 1785 return generic_write_check_limits(iocb->ki_filp, iocb->ki_pos, count);1786}1787EXPORT_SYMBOL(generic_write_checks_count);1788 1789/*1790 * Performs necessary checks before doing a write1791 *1792 * Can adjust writing position or amount of bytes to write.1793 * Returns appropriate error code that caller should return or1794 * zero in case that write should be allowed.1795 */1796ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)1797{1798 loff_t count = iov_iter_count(from);1799 int ret;1800 1801 ret = generic_write_checks_count(iocb, &count);1802 if (ret)1803 return ret;1804 1805 iov_iter_truncate(from, count);1806 return iov_iter_count(from);1807}1808EXPORT_SYMBOL(generic_write_checks);1809 1810/*1811 * Performs common checks before doing a file copy/clone1812 * from @file_in to @file_out.1813 */1814int generic_file_rw_checks(struct file *file_in, struct file *file_out)1815{1816 struct inode *inode_in = file_inode(file_in);1817 struct inode *inode_out = file_inode(file_out);1818 1819 /* Don't copy dirs, pipes, sockets... */1820 if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))1821 return -EISDIR;1822 if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))1823 return -EINVAL;1824 1825 if (!(file_in->f_mode & FMODE_READ) ||1826 !(file_out->f_mode & FMODE_WRITE) ||1827 (file_out->f_flags & O_APPEND))1828 return -EBADF;1829 1830 return 0;1831}1832 1833bool generic_atomic_write_valid(struct iov_iter *iter, loff_t pos)1834{1835 size_t len = iov_iter_count(iter);1836 1837 if (!iter_is_ubuf(iter))1838 return false;1839 1840 if (!is_power_of_2(len))1841 return false;1842 1843 if (!IS_ALIGNED(pos, len))1844 return false;1845 1846 return true;1847}1848