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WSL2-Linux-Kernel
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WSL2-Linux-Kernel/fs/read_write.c

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52 KiB
C
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// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/read_write.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/sched/xacct.h>
#include <linux/fcntl.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/fsnotify.h>
#include <linux/security.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include <linux/splice.h>
#include <linux/compat.h>
#include <linux/mount.h>
#include <linux/fs.h>
#include "internal.h"
#include <linux/uaccess.h>
#include <asm/unistd.h>
const struct file_operations generic_ro_fops = {
.llseek = generic_file_llseek,
.read_iter = generic_file_read_iter,
.mmap = generic_file_readonly_mmap,
.splice_read = generic_file_splice_read,
};
EXPORT_SYMBOL(generic_ro_fops);
static inline bool unsigned_offsets(struct file *file)
{
return file->f_mode & FMODE_UNSIGNED_OFFSET;
}
/**
* vfs_setpos - update the file offset for lseek
* @file: file structure in question
* @offset: file offset to seek to
* @maxsize: maximum file size
*
* This is a low-level filesystem helper for updating the file offset to
* the value specified by @offset if the given offset is valid and it is
* not equal to the current file offset.
*
* Return the specified offset on success and -EINVAL on invalid offset.
*/
loff_t vfs_setpos(struct file *file, loff_t offset, loff_t maxsize)
{
if (offset < 0 && !unsigned_offsets(file))
return -EINVAL;
if (offset > maxsize)
return -EINVAL;
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
return offset;
}
EXPORT_SYMBOL(vfs_setpos);
/**
* generic_file_llseek_size - generic llseek implementation for regular files
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
* @size: max size of this file in file system
* @eof: offset used for SEEK_END position
*
* This is a variant of generic_file_llseek that allows passing in a custom
* maximum file size and a custom EOF position, for e.g. hashed directories
*
* Synchronization:
* SEEK_SET and SEEK_END are unsynchronized (but atomic on 64bit platforms)
* SEEK_CUR is synchronized against other SEEK_CURs, but not read/writes.
* read/writes behave like SEEK_SET against seeks.
*/
loff_t
generic_file_llseek_size(struct file *file, loff_t offset, int whence,
loff_t maxsize, loff_t eof)
{
switch (whence) {
case SEEK_END:
offset += eof;
break;
case SEEK_CUR:
/*
* Here we special-case the lseek(fd, 0, SEEK_CUR)
* position-querying operation. Avoid rewriting the "same"
* f_pos value back to the file because a concurrent read(),
* write() or lseek() might have altered it
*/
if (offset == 0)
return file->f_pos;
/*
* f_lock protects against read/modify/write race with other
* SEEK_CURs. Note that parallel writes and reads behave
* like SEEK_SET.
*/
spin_lock(&file->f_lock);
offset = vfs_setpos(file, file->f_pos + offset, maxsize);
spin_unlock(&file->f_lock);
return offset;
case SEEK_DATA:
/*
* In the generic case the entire file is data, so as long as
* offset isn't at the end of the file then the offset is data.
*/
if ((unsigned long long)offset >= eof)
return -ENXIO;
break;
case SEEK_HOLE:
/*
* There is a virtual hole at the end of the file, so as long as
* offset isn't i_size or larger, return i_size.
*/
if ((unsigned long long)offset >= eof)
return -ENXIO;
offset = eof;
break;
}
return vfs_setpos(file, offset, maxsize);
}
EXPORT_SYMBOL(generic_file_llseek_size);
/**
* generic_file_llseek - generic llseek implementation for regular files
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
*
* This is a generic implemenation of ->llseek useable for all normal local
* filesystems. It just updates the file offset to the value specified by
* @offset and @whence.
*/
loff_t generic_file_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file->f_mapping->host;
return generic_file_llseek_size(file, offset, whence,
inode->i_sb->s_maxbytes,
i_size_read(inode));
}
EXPORT_SYMBOL(generic_file_llseek);
/**
* fixed_size_llseek - llseek implementation for fixed-sized devices
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
* @size: size of the file
*
*/
loff_t fixed_size_llseek(struct file *file, loff_t offset, int whence, loff_t size)
{
switch (whence) {
case SEEK_SET: case SEEK_CUR: case SEEK_END:
return generic_file_llseek_size(file, offset, whence,
size, size);
default:
return -EINVAL;
}
}
EXPORT_SYMBOL(fixed_size_llseek);
/**
* no_seek_end_llseek - llseek implementation for fixed-sized devices
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
*
*/
loff_t no_seek_end_llseek(struct file *file, loff_t offset, int whence)
{
switch (whence) {
case SEEK_SET: case SEEK_CUR:
return generic_file_llseek_size(file, offset, whence,
OFFSET_MAX, 0);
default:
return -EINVAL;
}
}
EXPORT_SYMBOL(no_seek_end_llseek);
/**
* no_seek_end_llseek_size - llseek implementation for fixed-sized devices
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
* @size: maximal offset allowed
*
*/
loff_t no_seek_end_llseek_size(struct file *file, loff_t offset, int whence, loff_t size)
{
switch (whence) {
case SEEK_SET: case SEEK_CUR:
return generic_file_llseek_size(file, offset, whence,
size, 0);
default:
return -EINVAL;
}
}
EXPORT_SYMBOL(no_seek_end_llseek_size);
/**
* noop_llseek - No Operation Performed llseek implementation
* @file: file structure to seek on
* @offset: file offset to seek to
* @whence: type of seek
*
* This is an implementation of ->llseek useable for the rare special case when
* userspace expects the seek to succeed but the (device) file is actually not
* able to perform the seek. In this case you use noop_llseek() instead of
* falling back to the default implementation of ->llseek.
*/
loff_t noop_llseek(struct file *file, loff_t offset, int whence)
{
return file->f_pos;
}
EXPORT_SYMBOL(noop_llseek);
loff_t no_llseek(struct file *file, loff_t offset, int whence)
{
return -ESPIPE;
}
EXPORT_SYMBOL(no_llseek);
loff_t default_llseek(struct file *file, loff_t offset, int whence)
{
struct inode *inode = file_inode(file);
loff_t retval;
inode_lock(inode);
switch (whence) {
case SEEK_END:
offset += i_size_read(inode);
break;
case SEEK_CUR:
if (offset == 0) {
retval = file->f_pos;
goto out;
}
offset += file->f_pos;
break;
case SEEK_DATA:
/*
* In the generic case the entire file is data, so as
* long as offset isn't at the end of the file then the
* offset is data.
*/
if (offset >= inode->i_size) {
retval = -ENXIO;
goto out;
}
break;
case SEEK_HOLE:
/*
* There is a virtual hole at the end of the file, so
* as long as offset isn't i_size or larger, return
* i_size.
*/
if (offset >= inode->i_size) {
retval = -ENXIO;
goto out;
}
offset = inode->i_size;
break;
}
retval = -EINVAL;
if (offset >= 0 || unsigned_offsets(file)) {
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
retval = offset;
}
out:
inode_unlock(inode);
return retval;
}
EXPORT_SYMBOL(default_llseek);
loff_t vfs_llseek(struct file *file, loff_t offset, int whence)
{
loff_t (*fn)(struct file *, loff_t, int);
fn = no_llseek;
if (file->f_mode & FMODE_LSEEK) {
if (file->f_op->llseek)
fn = file->f_op->llseek;
}
return fn(file, offset, whence);
}
EXPORT_SYMBOL(vfs_llseek);
off_t ksys_lseek(unsigned int fd, off_t offset, unsigned int whence)
{
off_t retval;
struct fd f = fdget_pos(fd);
if (!f.file)
return -EBADF;
retval = -EINVAL;
if (whence <= SEEK_MAX) {
loff_t res = vfs_llseek(f.file, offset, whence);
retval = res;
if (res != (loff_t)retval)
retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
}
fdput_pos(f);
return retval;
}
SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, whence)
{
return ksys_lseek(fd, offset, whence);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE3(lseek, unsigned int, fd, compat_off_t, offset, unsigned int, whence)
{
return ksys_lseek(fd, offset, whence);
}
#endif
#if !defined(CONFIG_64BIT) || defined(CONFIG_COMPAT)
SYSCALL_DEFINE5(llseek, unsigned int, fd, unsigned long, offset_high,
unsigned long, offset_low, loff_t __user *, result,
unsigned int, whence)
{
int retval;
struct fd f = fdget_pos(fd);
loff_t offset;
if (!f.file)
return -EBADF;
retval = -EINVAL;
if (whence > SEEK_MAX)
goto out_putf;
offset = vfs_llseek(f.file, ((loff_t) offset_high << 32) | offset_low,
whence);
retval = (int)offset;
if (offset >= 0) {
retval = -EFAULT;
if (!copy_to_user(result, &offset, sizeof(offset)))
retval = 0;
}
out_putf:
fdput_pos(f);
return retval;
}
#endif
int rw_verify_area(int read_write, struct file *file, const loff_t *ppos, size_t count)
{
struct inode *inode;
int retval = -EINVAL;
inode = file_inode(file);
if (unlikely((ssize_t) count < 0))
return retval;
/*
* ranged mandatory locking does not apply to streams - it makes sense
* only for files where position has a meaning.
*/
if (ppos) {
loff_t pos = *ppos;
if (unlikely(pos < 0)) {
if (!unsigned_offsets(file))
return retval;
if (count >= -pos) /* both values are in 0..LLONG_MAX */
return -EOVERFLOW;
} else if (unlikely((loff_t) (pos + count) < 0)) {
if (!unsigned_offsets(file))
return retval;
}
if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
retval = locks_mandatory_area(inode, file, pos, pos + count - 1,
read_write == READ ? F_RDLCK : F_WRLCK);
if (retval < 0)
return retval;
}
}
return security_file_permission(file,
read_write == READ ? MAY_READ : MAY_WRITE);
}
static ssize_t new_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
struct iovec iov = { .iov_base = buf, .iov_len = len };
struct kiocb kiocb;
struct iov_iter iter;
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
kiocb.ki_pos = (ppos ? *ppos : 0);
iov_iter_init(&iter, READ, &iov, 1, len);
ret = call_read_iter(filp, &kiocb, &iter);
BUG_ON(ret == -EIOCBQUEUED);
if (ppos)
*ppos = kiocb.ki_pos;
return ret;
}
ssize_t __vfs_read(struct file *file, char __user *buf, size_t count,
loff_t *pos)
{
if (file->f_op->read)
return file->f_op->read(file, buf, count, pos);
else if (file->f_op->read_iter)
return new_sync_read(file, buf, count, pos);
else
return -EINVAL;
}
ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos)
{
mm_segment_t old_fs;
ssize_t result;
old_fs = get_fs();
set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
result = vfs_read(file, (void __user *)buf, count, pos);
set_fs(old_fs);
return result;
}
EXPORT_SYMBOL(kernel_read);
ssize_t vfs_read(struct file *file, char __user *buf, size_t count, loff_t *pos)
{
ssize_t ret;
if (!(file->f_mode & FMODE_READ))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
if (unlikely(!access_ok(buf, count)))
return -EFAULT;
ret = rw_verify_area(READ, file, pos, count);
if (!ret) {
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
ret = __vfs_read(file, buf, count, pos);
if (ret > 0) {
fsnotify_access(file);
add_rchar(current, ret);
}
inc_syscr(current);
}
return ret;
}
static ssize_t new_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
{
struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
struct kiocb kiocb;
struct iov_iter iter;
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
kiocb.ki_pos = (ppos ? *ppos : 0);
iov_iter_init(&iter, WRITE, &iov, 1, len);
ret = call_write_iter(filp, &kiocb, &iter);
BUG_ON(ret == -EIOCBQUEUED);
if (ret > 0 && ppos)
*ppos = kiocb.ki_pos;
return ret;
}
static ssize_t __vfs_write(struct file *file, const char __user *p,
size_t count, loff_t *pos)
{
if (file->f_op->write)
return file->f_op->write(file, p, count, pos);
else if (file->f_op->write_iter)
return new_sync_write(file, p, count, pos);
else
return -EINVAL;
}
ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos)
{
mm_segment_t old_fs;
const char __user *p;
ssize_t ret;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;
old_fs = get_fs();
set_fs(KERNEL_DS);
p = (__force const char __user *)buf;
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
ret = __vfs_write(file, p, count, pos);
set_fs(old_fs);
if (ret > 0) {
fsnotify_modify(file);
add_wchar(current, ret);
}
inc_syscw(current);
return ret;
}
EXPORT_SYMBOL(__kernel_write);
ssize_t kernel_write(struct file *file, const void *buf, size_t count,
loff_t *pos)
{
mm_segment_t old_fs;
ssize_t res;
old_fs = get_fs();
set_fs(KERNEL_DS);
/* The cast to a user pointer is valid due to the set_fs() */
res = vfs_write(file, (__force const char __user *)buf, count, pos);
set_fs(old_fs);
return res;
}
EXPORT_SYMBOL(kernel_write);
ssize_t vfs_write(struct file *file, const char __user *buf, size_t count, loff_t *pos)
{
ssize_t ret;
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;
if (unlikely(!access_ok(buf, count)))
return -EFAULT;
ret = rw_verify_area(WRITE, file, pos, count);
if (!ret) {
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
file_start_write(file);
ret = __vfs_write(file, buf, count, pos);
if (ret > 0) {
fsnotify_modify(file);
add_wchar(current, ret);
}
inc_syscw(current);
file_end_write(file);
}
return ret;
}
/* file_ppos returns &file->f_pos or NULL if file is stream */
static inline loff_t *file_ppos(struct file *file)
{
return file->f_mode & FMODE_STREAM ? NULL : &file->f_pos;
}
ssize_t ksys_read(unsigned int fd, char __user *buf, size_t count)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
if (f.file) {
loff_t pos, *ppos = file_ppos(f.file);
if (ppos) {
pos = *ppos;
ppos = &pos;
}
ret = vfs_read(f.file, buf, count, ppos);
if (ret >= 0 && ppos)
f.file->f_pos = pos;
fdput_pos(f);
}
return ret;
}
SYSCALL_DEFINE3(read, unsigned int, fd, char __user *, buf, size_t, count)
{
return ksys_read(fd, buf, count);
}
ssize_t ksys_write(unsigned int fd, const char __user *buf, size_t count)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
if (f.file) {
loff_t pos, *ppos = file_ppos(f.file);
if (ppos) {
pos = *ppos;
ppos = &pos;
}
ret = vfs_write(f.file, buf, count, ppos);
if (ret >= 0 && ppos)
f.file->f_pos = pos;
fdput_pos(f);
}
return ret;
}
SYSCALL_DEFINE3(write, unsigned int, fd, const char __user *, buf,
size_t, count)
{
return ksys_write(fd, buf, count);
}
ssize_t ksys_pread64(unsigned int fd, char __user *buf, size_t count,
loff_t pos)
{
struct fd f;
ssize_t ret = -EBADF;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PREAD)
ret = vfs_read(f.file, buf, count, &pos);
fdput(f);
}
return ret;
}
SYSCALL_DEFINE4(pread64, unsigned int, fd, char __user *, buf,
size_t, count, loff_t, pos)
{
return ksys_pread64(fd, buf, count, pos);
}
ssize_t ksys_pwrite64(unsigned int fd, const char __user *buf,
size_t count, loff_t pos)
{
struct fd f;
ssize_t ret = -EBADF;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PWRITE)
ret = vfs_write(f.file, buf, count, &pos);
fdput(f);
}
return ret;
}
SYSCALL_DEFINE4(pwrite64, unsigned int, fd, const char __user *, buf,
size_t, count, loff_t, pos)
{
return ksys_pwrite64(fd, buf, count, pos);
}
static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
loff_t *ppos, int type, rwf_t flags)
{
struct kiocb kiocb;
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
ret = kiocb_set_rw_flags(&kiocb, flags);
if (ret)
return ret;
kiocb.ki_pos = (ppos ? *ppos : 0);
if (type == READ)
ret = call_read_iter(filp, &kiocb, iter);
else
ret = call_write_iter(filp, &kiocb, iter);
BUG_ON(ret == -EIOCBQUEUED);
if (ppos)
*ppos = kiocb.ki_pos;
return ret;
}
/* Do it by hand, with file-ops */
static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
loff_t *ppos, int type, rwf_t flags)
{
ssize_t ret = 0;
if (flags & ~RWF_HIPRI)
return -EOPNOTSUPP;
while (iov_iter_count(iter)) {
struct iovec iovec = iov_iter_iovec(iter);
ssize_t nr;
if (type == READ) {
nr = filp->f_op->read(filp, iovec.iov_base,
iovec.iov_len, ppos);
} else {
nr = filp->f_op->write(filp, iovec.iov_base,
iovec.iov_len, ppos);
}
if (nr < 0) {
if (!ret)
ret = nr;
break;
}
ret += nr;
if (nr != iovec.iov_len)
break;
iov_iter_advance(iter, nr);
}
return ret;
}
/**
* rw_copy_check_uvector() - Copy an array of &struct iovec from userspace
* into the kernel and check that it is valid.
*
* @type: One of %CHECK_IOVEC_ONLY, %READ, or %WRITE.
* @uvector: Pointer to the userspace array.
* @nr_segs: Number of elements in userspace array.
* @fast_segs: Number of elements in @fast_pointer.
* @fast_pointer: Pointer to (usually small on-stack) kernel array.
* @ret_pointer: (output parameter) Pointer to a variable that will point to
* either @fast_pointer, a newly allocated kernel array, or NULL,
* depending on which array was used.
*
* This function copies an array of &struct iovec of @nr_segs from
* userspace into the kernel and checks that each element is valid (e.g.
* it does not point to a kernel address or cause overflow by being too
* large, etc.).
*
* As an optimization, the caller may provide a pointer to a small
* on-stack array in @fast_pointer, typically %UIO_FASTIOV elements long
* (the size of this array, or 0 if unused, should be given in @fast_segs).
*
* @ret_pointer will always point to the array that was used, so the
* caller must take care not to call kfree() on it e.g. in case the
* @fast_pointer array was used and it was allocated on the stack.
*
* Return: The total number of bytes covered by the iovec array on success
* or a negative error code on error.
*/
ssize_t rw_copy_check_uvector(int type, const struct iovec __user * uvector,
unsigned long nr_segs, unsigned long fast_segs,
struct iovec *fast_pointer,
struct iovec **ret_pointer)
{
unsigned long seg;
ssize_t ret;
struct iovec *iov = fast_pointer;
/*
* SuS says "The readv() function *may* fail if the iovcnt argument
* was less than or equal to 0, or greater than {IOV_MAX}. Linux has
* traditionally returned zero for zero segments, so...
*/
if (nr_segs == 0) {
ret = 0;
goto out;
}
/*
* First get the "struct iovec" from user memory and
* verify all the pointers
*/
if (nr_segs > UIO_MAXIOV) {
ret = -EINVAL;
goto out;
}
if (nr_segs > fast_segs) {
iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL);
if (iov == NULL) {
ret = -ENOMEM;
goto out;
}
}
if (copy_from_user(iov, uvector, nr_segs*sizeof(*uvector))) {
ret = -EFAULT;
goto out;
}
/*
* According to the Single Unix Specification we should return EINVAL
* if an element length is < 0 when cast to ssize_t or if the
* total length would overflow the ssize_t return value of the
* system call.
*
* Linux caps all read/write calls to MAX_RW_COUNT, and avoids the
* overflow case.
*/
ret = 0;
for (seg = 0; seg < nr_segs; seg++) {
void __user *buf = iov[seg].iov_base;
ssize_t len = (ssize_t)iov[seg].iov_len;
/* see if we we're about to use an invalid len or if
* it's about to overflow ssize_t */
if (len < 0) {
ret = -EINVAL;
goto out;
}
if (type >= 0
&& unlikely(!access_ok(buf, len))) {
ret = -EFAULT;
goto out;
}
if (len > MAX_RW_COUNT - ret) {
len = MAX_RW_COUNT - ret;
iov[seg].iov_len = len;
}
ret += len;
}
out:
*ret_pointer = iov;
return ret;
}
#ifdef CONFIG_COMPAT
ssize_t compat_rw_copy_check_uvector(int type,
const struct compat_iovec __user *uvector, unsigned long nr_segs,
unsigned long fast_segs, struct iovec *fast_pointer,
struct iovec **ret_pointer)
{
compat_ssize_t tot_len;
struct iovec *iov = *ret_pointer = fast_pointer;
ssize_t ret = 0;
int seg;
/*
* SuS says "The readv() function *may* fail if the iovcnt argument
* was less than or equal to 0, or greater than {IOV_MAX}. Linux has
* traditionally returned zero for zero segments, so...
*/
if (nr_segs == 0)
goto out;
ret = -EINVAL;
if (nr_segs > UIO_MAXIOV)
goto out;
if (nr_segs > fast_segs) {
ret = -ENOMEM;
iov = kmalloc_array(nr_segs, sizeof(struct iovec), GFP_KERNEL);
if (iov == NULL)
goto out;
}
*ret_pointer = iov;
ret = -EFAULT;
if (!access_ok(uvector, nr_segs*sizeof(*uvector)))
goto out;
/*
* Single unix specification:
* We should -EINVAL if an element length is not >= 0 and fitting an
* ssize_t.
*
* In Linux, the total length is limited to MAX_RW_COUNT, there is
* no overflow possibility.
*/
tot_len = 0;
ret = -EINVAL;
for (seg = 0; seg < nr_segs; seg++) {
compat_uptr_t buf;
compat_ssize_t len;
if (__get_user(len, &uvector->iov_len) ||
__get_user(buf, &uvector->iov_base)) {
ret = -EFAULT;
goto out;
}
if (len < 0) /* size_t not fitting in compat_ssize_t .. */
goto out;
if (type >= 0 &&
!access_ok(compat_ptr(buf), len)) {
ret = -EFAULT;
goto out;
}
if (len > MAX_RW_COUNT - tot_len)
len = MAX_RW_COUNT - tot_len;
tot_len += len;
iov->iov_base = compat_ptr(buf);
iov->iov_len = (compat_size_t) len;
uvector++;
iov++;
}
ret = tot_len;
out:
return ret;
}
#endif
static ssize_t do_iter_read(struct file *file, struct iov_iter *iter,
loff_t *pos, rwf_t flags)
{
size_t tot_len;
ssize_t ret = 0;
if (!(file->f_mode & FMODE_READ))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_READ))
return -EINVAL;
tot_len = iov_iter_count(iter);
if (!tot_len)
goto out;
ret = rw_verify_area(READ, file, pos, tot_len);
if (ret < 0)
return ret;
if (file->f_op->read_iter)
ret = do_iter_readv_writev(file, iter, pos, READ, flags);
else
ret = do_loop_readv_writev(file, iter, pos, READ, flags);
out:
if (ret >= 0)
fsnotify_access(file);
return ret;
}
ssize_t vfs_iter_read(struct file *file, struct iov_iter *iter, loff_t *ppos,
rwf_t flags)
{
if (!file->f_op->read_iter)
return -EINVAL;
return do_iter_read(file, iter, ppos, flags);
}
EXPORT_SYMBOL(vfs_iter_read);
static ssize_t do_iter_write(struct file *file, struct iov_iter *iter,
loff_t *pos, rwf_t flags)
{
size_t tot_len;
ssize_t ret = 0;
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
if (!(file->f_mode & FMODE_CAN_WRITE))
return -EINVAL;
tot_len = iov_iter_count(iter);
if (!tot_len)
return 0;
ret = rw_verify_area(WRITE, file, pos, tot_len);
if (ret < 0)
return ret;
if (file->f_op->write_iter)
ret = do_iter_readv_writev(file, iter, pos, WRITE, flags);
else
ret = do_loop_readv_writev(file, iter, pos, WRITE, flags);
if (ret > 0)
fsnotify_modify(file);
return ret;
}
ssize_t vfs_iter_write(struct file *file, struct iov_iter *iter, loff_t *ppos,
rwf_t flags)
{
if (!file->f_op->write_iter)
return -EINVAL;
return do_iter_write(file, iter, ppos, flags);
}
EXPORT_SYMBOL(vfs_iter_write);
ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
ssize_t ret;
ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
if (ret >= 0) {
ret = do_iter_read(file, &iter, pos, flags);
kfree(iov);
}
return ret;
}
static ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
ssize_t ret;
ret = import_iovec(WRITE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
if (ret >= 0) {
file_start_write(file);
ret = do_iter_write(file, &iter, pos, flags);
file_end_write(file);
kfree(iov);
}
return ret;
}
static ssize_t do_readv(unsigned long fd, const struct iovec __user *vec,
unsigned long vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
if (f.file) {
loff_t pos, *ppos = file_ppos(f.file);
if (ppos) {
pos = *ppos;
ppos = &pos;
}
ret = vfs_readv(f.file, vec, vlen, ppos, flags);
if (ret >= 0 && ppos)
f.file->f_pos = pos;
fdput_pos(f);
}
if (ret > 0)
add_rchar(current, ret);
inc_syscr(current);
return ret;
}
static ssize_t do_writev(unsigned long fd, const struct iovec __user *vec,
unsigned long vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret = -EBADF;
if (f.file) {
loff_t pos, *ppos = file_ppos(f.file);
if (ppos) {
pos = *ppos;
ppos = &pos;
}
ret = vfs_writev(f.file, vec, vlen, ppos, flags);
if (ret >= 0 && ppos)
f.file->f_pos = pos;
fdput_pos(f);
}
if (ret > 0)
add_wchar(current, ret);
inc_syscw(current);
return ret;
}
static inline loff_t pos_from_hilo(unsigned long high, unsigned long low)
{
#define HALF_LONG_BITS (BITS_PER_LONG / 2)
return (((loff_t)high << HALF_LONG_BITS) << HALF_LONG_BITS) | low;
}
static ssize_t do_preadv(unsigned long fd, const struct iovec __user *vec,
unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret = -EBADF;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PREAD)
ret = vfs_readv(f.file, vec, vlen, &pos, flags);
fdput(f);
}
if (ret > 0)
add_rchar(current, ret);
inc_syscr(current);
return ret;
}
static ssize_t do_pwritev(unsigned long fd, const struct iovec __user *vec,
unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret = -EBADF;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (f.file) {
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PWRITE)
ret = vfs_writev(f.file, vec, vlen, &pos, flags);
fdput(f);
}
if (ret > 0)
add_wchar(current, ret);
inc_syscw(current);
return ret;
}
SYSCALL_DEFINE3(readv, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen)
{
return do_readv(fd, vec, vlen, 0);
}
SYSCALL_DEFINE3(writev, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen)
{
return do_writev(fd, vec, vlen, 0);
}
SYSCALL_DEFINE5(preadv, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);
return do_preadv(fd, vec, vlen, pos, 0);
}
SYSCALL_DEFINE6(preadv2, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
rwf_t, flags)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);
if (pos == -1)
return do_readv(fd, vec, vlen, flags);
return do_preadv(fd, vec, vlen, pos, flags);
}
SYSCALL_DEFINE5(pwritev, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);
return do_pwritev(fd, vec, vlen, pos, 0);
}
SYSCALL_DEFINE6(pwritev2, unsigned long, fd, const struct iovec __user *, vec,
unsigned long, vlen, unsigned long, pos_l, unsigned long, pos_h,
rwf_t, flags)
{
loff_t pos = pos_from_hilo(pos_h, pos_l);
if (pos == -1)
return do_writev(fd, vec, vlen, flags);
return do_pwritev(fd, vec, vlen, pos, flags);
}
#ifdef CONFIG_COMPAT
static size_t compat_readv(struct file *file,
const struct compat_iovec __user *vec,
unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
ssize_t ret;
ret = compat_import_iovec(READ, vec, vlen, UIO_FASTIOV, &iov, &iter);
if (ret >= 0) {
ret = do_iter_read(file, &iter, pos, flags);
kfree(iov);
}
if (ret > 0)
add_rchar(current, ret);
inc_syscr(current);
return ret;
}
static size_t do_compat_readv(compat_ulong_t fd,
const struct compat_iovec __user *vec,
compat_ulong_t vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret;
loff_t pos;
if (!f.file)
return -EBADF;
pos = f.file->f_pos;
ret = compat_readv(f.file, vec, vlen, &pos, flags);
if (ret >= 0)
f.file->f_pos = pos;
fdput_pos(f);
return ret;
}
COMPAT_SYSCALL_DEFINE3(readv, compat_ulong_t, fd,
const struct compat_iovec __user *,vec,
compat_ulong_t, vlen)
{
return do_compat_readv(fd, vec, vlen, 0);
}
static long do_compat_preadv64(unsigned long fd,
const struct compat_iovec __user *vec,
unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (!f.file)
return -EBADF;
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PREAD)
ret = compat_readv(f.file, vec, vlen, &pos, flags);
fdput(f);
return ret;
}
#ifdef __ARCH_WANT_COMPAT_SYS_PREADV64
COMPAT_SYSCALL_DEFINE4(preadv64, unsigned long, fd,
const struct compat_iovec __user *,vec,
unsigned long, vlen, loff_t, pos)
{
return do_compat_preadv64(fd, vec, vlen, pos, 0);
}
#endif
COMPAT_SYSCALL_DEFINE5(preadv, compat_ulong_t, fd,
const struct compat_iovec __user *,vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
return do_compat_preadv64(fd, vec, vlen, pos, 0);
}
#ifdef __ARCH_WANT_COMPAT_SYS_PREADV64V2
COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,
const struct compat_iovec __user *,vec,
unsigned long, vlen, loff_t, pos, rwf_t, flags)
{
if (pos == -1)
return do_compat_readv(fd, vec, vlen, flags);
return do_compat_preadv64(fd, vec, vlen, pos, flags);
}
#endif
COMPAT_SYSCALL_DEFINE6(preadv2, compat_ulong_t, fd,
const struct compat_iovec __user *,vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high,
rwf_t, flags)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
if (pos == -1)
return do_compat_readv(fd, vec, vlen, flags);
return do_compat_preadv64(fd, vec, vlen, pos, flags);
}
static size_t compat_writev(struct file *file,
const struct compat_iovec __user *vec,
unsigned long vlen, loff_t *pos, rwf_t flags)
{
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov = iovstack;
struct iov_iter iter;
ssize_t ret;
ret = compat_import_iovec(WRITE, vec, vlen, UIO_FASTIOV, &iov, &iter);
if (ret >= 0) {
file_start_write(file);
ret = do_iter_write(file, &iter, pos, flags);
file_end_write(file);
kfree(iov);
}
if (ret > 0)
add_wchar(current, ret);
inc_syscw(current);
return ret;
}
static size_t do_compat_writev(compat_ulong_t fd,
const struct compat_iovec __user* vec,
compat_ulong_t vlen, rwf_t flags)
{
struct fd f = fdget_pos(fd);
ssize_t ret;
loff_t pos;
if (!f.file)
return -EBADF;
pos = f.file->f_pos;
ret = compat_writev(f.file, vec, vlen, &pos, flags);
if (ret >= 0)
f.file->f_pos = pos;
fdput_pos(f);
return ret;
}
COMPAT_SYSCALL_DEFINE3(writev, compat_ulong_t, fd,
const struct compat_iovec __user *, vec,
compat_ulong_t, vlen)
{
return do_compat_writev(fd, vec, vlen, 0);
}
static long do_compat_pwritev64(unsigned long fd,
const struct compat_iovec __user *vec,
unsigned long vlen, loff_t pos, rwf_t flags)
{
struct fd f;
ssize_t ret;
if (pos < 0)
return -EINVAL;
f = fdget(fd);
if (!f.file)
return -EBADF;
ret = -ESPIPE;
if (f.file->f_mode & FMODE_PWRITE)
ret = compat_writev(f.file, vec, vlen, &pos, flags);
fdput(f);
return ret;
}
#ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64
COMPAT_SYSCALL_DEFINE4(pwritev64, unsigned long, fd,
const struct compat_iovec __user *,vec,
unsigned long, vlen, loff_t, pos)
{
return do_compat_pwritev64(fd, vec, vlen, pos, 0);
}
#endif
COMPAT_SYSCALL_DEFINE5(pwritev, compat_ulong_t, fd,
const struct compat_iovec __user *,vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
return do_compat_pwritev64(fd, vec, vlen, pos, 0);
}
#ifdef __ARCH_WANT_COMPAT_SYS_PWRITEV64V2
COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,
const struct compat_iovec __user *,vec,
unsigned long, vlen, loff_t, pos, rwf_t, flags)
{
if (pos == -1)
return do_compat_writev(fd, vec, vlen, flags);
return do_compat_pwritev64(fd, vec, vlen, pos, flags);
}
#endif
COMPAT_SYSCALL_DEFINE6(pwritev2, compat_ulong_t, fd,
const struct compat_iovec __user *,vec,
compat_ulong_t, vlen, u32, pos_low, u32, pos_high, rwf_t, flags)
{
loff_t pos = ((loff_t)pos_high << 32) | pos_low;
if (pos == -1)
return do_compat_writev(fd, vec, vlen, flags);
return do_compat_pwritev64(fd, vec, vlen, pos, flags);
}
#endif
static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
size_t count, loff_t max)
{
struct fd in, out;
struct inode *in_inode, *out_inode;
loff_t pos;
loff_t out_pos;
ssize_t retval;
int fl;
/*
* Get input file, and verify that it is ok..
*/
retval = -EBADF;
in = fdget(in_fd);
if (!in.file)
goto out;
if (!(in.file->f_mode & FMODE_READ))
goto fput_in;
retval = -ESPIPE;
if (!ppos) {
pos = in.file->f_pos;
} else {
pos = *ppos;
if (!(in.file->f_mode & FMODE_PREAD))
goto fput_in;
}
retval = rw_verify_area(READ, in.file, &pos, count);
if (retval < 0)
goto fput_in;
if (count > MAX_RW_COUNT)
count = MAX_RW_COUNT;
/*
* Get output file, and verify that it is ok..
*/
retval = -EBADF;
out = fdget(out_fd);
if (!out.file)
goto fput_in;
if (!(out.file->f_mode & FMODE_WRITE))
goto fput_out;
in_inode = file_inode(in.file);
out_inode = file_inode(out.file);
out_pos = out.file->f_pos;
retval = rw_verify_area(WRITE, out.file, &out_pos, count);
if (retval < 0)
goto fput_out;
if (!max)
max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
if (unlikely(pos + count > max)) {
retval = -EOVERFLOW;
if (pos >= max)
goto fput_out;
count = max - pos;
}
fl = 0;
#if 0
/*
* We need to debate whether we can enable this or not. The
* man page documents EAGAIN return for the output at least,
* and the application is arguably buggy if it doesn't expect
* EAGAIN on a non-blocking file descriptor.
*/
if (in.file->f_flags & O_NONBLOCK)
fl = SPLICE_F_NONBLOCK;
#endif
file_start_write(out.file);
retval = do_splice_direct(in.file, &pos, out.file, &out_pos, count, fl);
file_end_write(out.file);
if (retval > 0) {
add_rchar(current, retval);
add_wchar(current, retval);
fsnotify_access(in.file);
fsnotify_modify(out.file);
out.file->f_pos = out_pos;
if (ppos)
*ppos = pos;
else
in.file->f_pos = pos;
}
inc_syscr(current);
inc_syscw(current);
if (pos > max)
retval = -EOVERFLOW;
fput_out:
fdput(out);
fput_in:
fdput(in);
out:
return retval;
}
SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd, off_t __user *, offset, size_t, count)
{
loff_t pos;
off_t off;
ssize_t ret;
if (offset) {
if (unlikely(get_user(off, offset)))
return -EFAULT;
pos = off;
ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd, loff_t __user *, offset, size_t, count)
{
loff_t pos;
ssize_t ret;
if (offset) {
if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
return -EFAULT;
ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE4(sendfile, int, out_fd, int, in_fd,
compat_off_t __user *, offset, compat_size_t, count)
{
loff_t pos;
off_t off;
ssize_t ret;
if (offset) {
if (unlikely(get_user(off, offset)))
return -EFAULT;
pos = off;
ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
COMPAT_SYSCALL_DEFINE4(sendfile64, int, out_fd, int, in_fd,
compat_loff_t __user *, offset, compat_size_t, count)
{
loff_t pos;
ssize_t ret;
if (offset) {
if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
return -EFAULT;
ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
if (unlikely(put_user(pos, offset)))
return -EFAULT;
return ret;
}
return do_sendfile(out_fd, in_fd, NULL, count, 0);
}
#endif
/**
* generic_copy_file_range - copy data between two files
* @file_in: file structure to read from
* @pos_in: file offset to read from
* @file_out: file structure to write data to
* @pos_out: file offset to write data to
* @len: amount of data to copy
* @flags: copy flags
*
* This is a generic filesystem helper to copy data from one file to another.
* It has no constraints on the source or destination file owners - the files
* can belong to different superblocks and different filesystem types. Short
* copies are allowed.
*
* This should be called from the @file_out filesystem, as per the
* ->copy_file_range() method.
*
* Returns the number of bytes copied or a negative error indicating the
* failure.
*/
ssize_t generic_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
return do_splice_direct(file_in, &pos_in, file_out, &pos_out,
len > MAX_RW_COUNT ? MAX_RW_COUNT : len, 0);
}
EXPORT_SYMBOL(generic_copy_file_range);
static ssize_t do_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
/*
* Although we now allow filesystems to handle cross sb copy, passing
* a file of the wrong filesystem type to filesystem driver can result
* in an attempt to dereference the wrong type of ->private_data, so
* avoid doing that until we really have a good reason. NFS defines
* several different file_system_type structures, but they all end up
* using the same ->copy_file_range() function pointer.
*/
if (file_out->f_op->copy_file_range &&
file_out->f_op->copy_file_range == file_in->f_op->copy_file_range)
return file_out->f_op->copy_file_range(file_in, pos_in,
file_out, pos_out,
len, flags);
return generic_copy_file_range(file_in, pos_in, file_out, pos_out, len,
flags);
}
/*
* copy_file_range() differs from regular file read and write in that it
* specifically allows return partial success. When it does so is up to
* the copy_file_range method.
*/
ssize_t vfs_copy_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
size_t len, unsigned int flags)
{
ssize_t ret;
if (flags != 0)
return -EINVAL;
ret = generic_copy_file_checks(file_in, pos_in, file_out, pos_out, &len,
flags);
if (unlikely(ret))
return ret;
ret = rw_verify_area(READ, file_in, &pos_in, len);
if (unlikely(ret))
return ret;
ret = rw_verify_area(WRITE, file_out, &pos_out, len);
if (unlikely(ret))
return ret;
if (len == 0)
return 0;
file_start_write(file_out);
/*
* Try cloning first, this is supported by more file systems, and
* more efficient if both clone and copy are supported (e.g. NFS).
*/
if (file_in->f_op->remap_file_range &&
file_inode(file_in)->i_sb == file_inode(file_out)->i_sb) {
loff_t cloned;
cloned = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out,
min_t(loff_t, MAX_RW_COUNT, len),
REMAP_FILE_CAN_SHORTEN);
if (cloned > 0) {
ret = cloned;
goto done;
}
}
ret = do_copy_file_range(file_in, pos_in, file_out, pos_out, len,
flags);
WARN_ON_ONCE(ret == -EOPNOTSUPP);
done:
if (ret > 0) {
fsnotify_access(file_in);
add_rchar(current, ret);
fsnotify_modify(file_out);
add_wchar(current, ret);
}
inc_syscr(current);
inc_syscw(current);
file_end_write(file_out);
return ret;
}
EXPORT_SYMBOL(vfs_copy_file_range);
SYSCALL_DEFINE6(copy_file_range, int, fd_in, loff_t __user *, off_in,
int, fd_out, loff_t __user *, off_out,
size_t, len, unsigned int, flags)
{
loff_t pos_in;
loff_t pos_out;
struct fd f_in;
struct fd f_out;
ssize_t ret = -EBADF;
f_in = fdget(fd_in);
if (!f_in.file)
goto out2;
f_out = fdget(fd_out);
if (!f_out.file)
goto out1;
ret = -EFAULT;
if (off_in) {
if (copy_from_user(&pos_in, off_in, sizeof(loff_t)))
goto out;
} else {
pos_in = f_in.file->f_pos;
}
if (off_out) {
if (copy_from_user(&pos_out, off_out, sizeof(loff_t)))
goto out;
} else {
pos_out = f_out.file->f_pos;
}
ret = vfs_copy_file_range(f_in.file, pos_in, f_out.file, pos_out, len,
flags);
if (ret > 0) {
pos_in += ret;
pos_out += ret;
if (off_in) {
if (copy_to_user(off_in, &pos_in, sizeof(loff_t)))
ret = -EFAULT;
} else {
f_in.file->f_pos = pos_in;
}
if (off_out) {
if (copy_to_user(off_out, &pos_out, sizeof(loff_t)))
ret = -EFAULT;
} else {
f_out.file->f_pos = pos_out;
}
}
out:
fdput(f_out);
out1:
fdput(f_in);
out2:
return ret;
}
static int remap_verify_area(struct file *file, loff_t pos, loff_t len,
bool write)
{
struct inode *inode = file_inode(file);
if (unlikely(pos < 0 || len < 0))
return -EINVAL;
if (unlikely((loff_t) (pos + len) < 0))
return -EINVAL;
if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
loff_t end = len ? pos + len - 1 : OFFSET_MAX;
int retval;
retval = locks_mandatory_area(inode, file, pos, end,
write ? F_WRLCK : F_RDLCK);
if (retval < 0)
return retval;
}
return security_file_permission(file, write ? MAY_WRITE : MAY_READ);
}
/*
* Ensure that we don't remap a partial EOF block in the middle of something
* else. Assume that the offsets have already been checked for block
* alignment.
*
* For clone we only link a partial EOF block above or at the destination file's
* EOF. For deduplication we accept a partial EOF block only if it ends at the
* destination file's EOF (can not link it into the middle of a file).
*
* Shorten the request if possible.
*/
static int generic_remap_check_len(struct inode *inode_in,
struct inode *inode_out,
loff_t pos_out,
loff_t *len,
unsigned int remap_flags)
{
u64 blkmask = i_blocksize(inode_in) - 1;
loff_t new_len = *len;
if ((*len & blkmask) == 0)
return 0;
if (pos_out + *len < i_size_read(inode_out))
new_len &= ~blkmask;
if (new_len == *len)
return 0;
if (remap_flags & REMAP_FILE_CAN_SHORTEN) {
*len = new_len;
return 0;
}
return (remap_flags & REMAP_FILE_DEDUP) ? -EBADE : -EINVAL;
}
/* Read a page's worth of file data into the page cache. */
static struct page *vfs_dedupe_get_page(struct inode *inode, loff_t offset)
{
struct page *page;
page = read_mapping_page(inode->i_mapping, offset >> PAGE_SHIFT, NULL);
if (IS_ERR(page))
return page;
if (!PageUptodate(page)) {
put_page(page);
return ERR_PTR(-EIO);
}
return page;
}
/*
* Lock two pages, ensuring that we lock in offset order if the pages are from
* the same file.
*/
static void vfs_lock_two_pages(struct page *page1, struct page *page2)
{
/* Always lock in order of increasing index. */
if (page1->index > page2->index)
swap(page1, page2);
lock_page(page1);
if (page1 != page2)
lock_page(page2);
}
/* Unlock two pages, being careful not to unlock the same page twice. */
static void vfs_unlock_two_pages(struct page *page1, struct page *page2)
{
unlock_page(page1);
if (page1 != page2)
unlock_page(page2);
}
/*
* Compare extents of two files to see if they are the same.
* Caller must have locked both inodes to prevent write races.
*/
static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff,
struct inode *dest, loff_t destoff,
loff_t len, bool *is_same)
{
loff_t src_poff;
loff_t dest_poff;
void *src_addr;
void *dest_addr;
struct page *src_page;
struct page *dest_page;
loff_t cmp_len;
bool same;
int error;
error = -EINVAL;
same = true;
while (len) {
src_poff = srcoff & (PAGE_SIZE - 1);
dest_poff = destoff & (PAGE_SIZE - 1);
cmp_len = min(PAGE_SIZE - src_poff,
PAGE_SIZE - dest_poff);
cmp_len = min(cmp_len, len);
if (cmp_len <= 0)
goto out_error;
src_page = vfs_dedupe_get_page(src, srcoff);
if (IS_ERR(src_page)) {
error = PTR_ERR(src_page);
goto out_error;
}
dest_page = vfs_dedupe_get_page(dest, destoff);
if (IS_ERR(dest_page)) {
error = PTR_ERR(dest_page);
put_page(src_page);
goto out_error;
}
vfs_lock_two_pages(src_page, dest_page);
/*
* Now that we've locked both pages, make sure they're still
* mapped to the file data we're interested in. If not,
* someone is invalidating pages on us and we lose.
*/
if (!PageUptodate(src_page) || !PageUptodate(dest_page) ||
src_page->mapping != src->i_mapping ||
dest_page->mapping != dest->i_mapping) {
same = false;
goto unlock;
}
src_addr = kmap_atomic(src_page);
dest_addr = kmap_atomic(dest_page);
flush_dcache_page(src_page);
flush_dcache_page(dest_page);
if (memcmp(src_addr + src_poff, dest_addr + dest_poff, cmp_len))
same = false;
kunmap_atomic(dest_addr);
kunmap_atomic(src_addr);
unlock:
vfs_unlock_two_pages(src_page, dest_page);
put_page(dest_page);
put_page(src_page);
if (!same)
break;
srcoff += cmp_len;
destoff += cmp_len;
len -= cmp_len;
}
*is_same = same;
return 0;
out_error:
return error;
}
/*
* Check that the two inodes are eligible for cloning, the ranges make
* sense, and then flush all dirty data. Caller must ensure that the
* inodes have been locked against any other modifications.
*
* If there's an error, then the usual negative error code is returned.
* Otherwise returns 0 with *len set to the request length.
*/
int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t *len, unsigned int remap_flags)
{
struct inode *inode_in = file_inode(file_in);
struct inode *inode_out = file_inode(file_out);
bool same_inode = (inode_in == inode_out);
int ret;
/* Don't touch certain kinds of inodes */
if (IS_IMMUTABLE(inode_out))
return -EPERM;
if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out))
return -ETXTBSY;
/* Don't reflink dirs, pipes, sockets... */
if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode))
return -EISDIR;
if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode))
return -EINVAL;
/* Zero length dedupe exits immediately; reflink goes to EOF. */
if (*len == 0) {
loff_t isize = i_size_read(inode_in);
if ((remap_flags & REMAP_FILE_DEDUP) || pos_in == isize)
return 0;
if (pos_in > isize)
return -EINVAL;
*len = isize - pos_in;
if (*len == 0)
return 0;
}
/* Check that we don't violate system file offset limits. */
ret = generic_remap_checks(file_in, pos_in, file_out, pos_out, len,
remap_flags);
if (ret)
return ret;
/* Wait for the completion of any pending IOs on both files */
inode_dio_wait(inode_in);
if (!same_inode)
inode_dio_wait(inode_out);
ret = filemap_write_and_wait_range(inode_in->i_mapping,
pos_in, pos_in + *len - 1);
if (ret)
return ret;
ret = filemap_write_and_wait_range(inode_out->i_mapping,
pos_out, pos_out + *len - 1);
if (ret)
return ret;
/*
* Check that the extents are the same.
*/
if (remap_flags & REMAP_FILE_DEDUP) {
bool is_same = false;
ret = vfs_dedupe_file_range_compare(inode_in, pos_in,
inode_out, pos_out, *len, &is_same);
if (ret)
return ret;
if (!is_same)
return -EBADE;
}
ret = generic_remap_check_len(inode_in, inode_out, pos_out, len,
remap_flags);
if (ret)
return ret;
/* If can't alter the file contents, we're done. */
if (!(remap_flags & REMAP_FILE_DEDUP))
ret = file_modified(file_out);
return ret;
}
EXPORT_SYMBOL(generic_remap_file_range_prep);
loff_t do_clone_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t len, unsigned int remap_flags)
{
loff_t ret;
WARN_ON_ONCE(remap_flags & REMAP_FILE_DEDUP);
/*
* FICLONE/FICLONERANGE ioctls enforce that src and dest files are on
* the same mount. Practically, they only need to be on the same file
* system.
*/
if (file_inode(file_in)->i_sb != file_inode(file_out)->i_sb)
return -EXDEV;
ret = generic_file_rw_checks(file_in, file_out);
if (ret < 0)
return ret;
if (!file_in->f_op->remap_file_range)
return -EOPNOTSUPP;
ret = remap_verify_area(file_in, pos_in, len, false);
if (ret)
return ret;
ret = remap_verify_area(file_out, pos_out, len, true);
if (ret)
return ret;
ret = file_in->f_op->remap_file_range(file_in, pos_in,
file_out, pos_out, len, remap_flags);
if (ret < 0)
return ret;
fsnotify_access(file_in);
fsnotify_modify(file_out);
return ret;
}
EXPORT_SYMBOL(do_clone_file_range);
loff_t vfs_clone_file_range(struct file *file_in, loff_t pos_in,
struct file *file_out, loff_t pos_out,
loff_t len, unsigned int remap_flags)
{
loff_t ret;
file_start_write(file_out);
ret = do_clone_file_range(file_in, pos_in, file_out, pos_out, len,
remap_flags);
file_end_write(file_out);
return ret;
}
EXPORT_SYMBOL(vfs_clone_file_range);
/* Check whether we are allowed to dedupe the destination file */
static bool allow_file_dedupe(struct file *file)
{
if (capable(CAP_SYS_ADMIN))
return true;
if (file->f_mode & FMODE_WRITE)
return true;
if (uid_eq(current_fsuid(), file_inode(file)->i_uid))
return true;
if (!inode_permission(file_inode(file), MAY_WRITE))
return true;
return false;
}
loff_t vfs_dedupe_file_range_one(struct file *src_file, loff_t src_pos,
struct file *dst_file, loff_t dst_pos,
loff_t len, unsigned int remap_flags)
{
loff_t ret;
WARN_ON_ONCE(remap_flags & ~(REMAP_FILE_DEDUP |
REMAP_FILE_CAN_SHORTEN));
ret = mnt_want_write_file(dst_file);
if (ret)
return ret;
ret = remap_verify_area(dst_file, dst_pos, len, true);
if (ret < 0)
goto out_drop_write;
ret = -EPERM;
if (!allow_file_dedupe(dst_file))
goto out_drop_write;
ret = -EXDEV;
if (src_file->f_path.mnt != dst_file->f_path.mnt)
goto out_drop_write;
ret = -EISDIR;
if (S_ISDIR(file_inode(dst_file)->i_mode))
goto out_drop_write;
ret = -EINVAL;
if (!dst_file->f_op->remap_file_range)
goto out_drop_write;
if (len == 0) {
ret = 0;
goto out_drop_write;
}
ret = dst_file->f_op->remap_file_range(src_file, src_pos, dst_file,
dst_pos, len, remap_flags | REMAP_FILE_DEDUP);
out_drop_write:
mnt_drop_write_file(dst_file);
return ret;
}
EXPORT_SYMBOL(vfs_dedupe_file_range_one);
int vfs_dedupe_file_range(struct file *file, struct file_dedupe_range *same)
{
struct file_dedupe_range_info *info;
struct inode *src = file_inode(file);
u64 off;
u64 len;
int i;
int ret;
u16 count = same->dest_count;
loff_t deduped;
if (!(file->f_mode & FMODE_READ))
return -EINVAL;
if (same->reserved1 || same->reserved2)
return -EINVAL;
off = same->src_offset;
len = same->src_length;
if (S_ISDIR(src->i_mode))
return -EISDIR;
if (!S_ISREG(src->i_mode))
return -EINVAL;
if (!file->f_op->remap_file_range)
return -EOPNOTSUPP;
ret = remap_verify_area(file, off, len, false);
if (ret < 0)
return ret;
ret = 0;
if (off + len > i_size_read(src))
return -EINVAL;
/* Arbitrary 1G limit on a single dedupe request, can be raised. */
len = min_t(u64, len, 1 << 30);
/* pre-format output fields to sane values */
for (i = 0; i < count; i++) {
same->info[i].bytes_deduped = 0ULL;
same->info[i].status = FILE_DEDUPE_RANGE_SAME;
}
for (i = 0, info = same->info; i < count; i++, info++) {
struct fd dst_fd = fdget(info->dest_fd);
struct file *dst_file = dst_fd.file;
if (!dst_file) {
info->status = -EBADF;
goto next_loop;
}
if (info->reserved) {
info->status = -EINVAL;
goto next_fdput;
}
deduped = vfs_dedupe_file_range_one(file, off, dst_file,
info->dest_offset, len,
REMAP_FILE_CAN_SHORTEN);
if (deduped == -EBADE)
info->status = FILE_DEDUPE_RANGE_DIFFERS;
else if (deduped < 0)
info->status = deduped;
else
info->bytes_deduped = len;
next_fdput:
fdput(dst_fd);
next_loop:
if (fatal_signal_pending(current))
break;
}
return ret;
}
EXPORT_SYMBOL(vfs_dedupe_file_range);
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