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OpenCloudOS-Kernel
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OpenCloudOS-Kernel/fs/read_write.c

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/*
* linux/fs/read_write.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*/
#include <linux/slab.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/smp_lock.h>
#include <linux/dnotify.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/syscalls.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
struct file_operations generic_ro_fops = {
.llseek = generic_file_llseek,
.read = generic_file_read,
.mmap = generic_file_readonly_mmap,
.sendfile = generic_file_sendfile,
};
EXPORT_SYMBOL(generic_ro_fops);
loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
{
long long retval;
struct inode *inode = file->f_mapping->host;
down(&inode->i_sem);
switch (origin) {
case 2:
offset += inode->i_size;
break;
case 1:
offset += file->f_pos;
}
retval = -EINVAL;
if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
retval = offset;
}
up(&inode->i_sem);
return retval;
}
EXPORT_SYMBOL(generic_file_llseek);
loff_t remote_llseek(struct file *file, loff_t offset, int origin)
{
long long retval;
lock_kernel();
switch (origin) {
case 2:
offset += i_size_read(file->f_dentry->d_inode);
break;
case 1:
offset += file->f_pos;
}
retval = -EINVAL;
if (offset>=0 && offset<=file->f_dentry->d_inode->i_sb->s_maxbytes) {
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
retval = offset;
}
unlock_kernel();
return retval;
}
EXPORT_SYMBOL(remote_llseek);
loff_t no_llseek(struct file *file, loff_t offset, int origin)
{
return -ESPIPE;
}
EXPORT_SYMBOL(no_llseek);
loff_t default_llseek(struct file *file, loff_t offset, int origin)
{
long long retval;
lock_kernel();
switch (origin) {
case 2:
offset += i_size_read(file->f_dentry->d_inode);
break;
case 1:
offset += file->f_pos;
}
retval = -EINVAL;
if (offset >= 0) {
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
}
retval = offset;
}
unlock_kernel();
return retval;
}
EXPORT_SYMBOL(default_llseek);
loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
{
loff_t (*fn)(struct file *, loff_t, int);
fn = no_llseek;
if (file->f_mode & FMODE_LSEEK) {
fn = default_llseek;
if (file->f_op && file->f_op->llseek)
fn = file->f_op->llseek;
}
return fn(file, offset, origin);
}
EXPORT_SYMBOL(vfs_llseek);
asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
{
off_t retval;
struct file * file;
int fput_needed;
retval = -EBADF;
file = fget_light(fd, &fput_needed);
if (!file)
goto bad;
retval = -EINVAL;
if (origin <= 2) {
loff_t res = vfs_llseek(file, offset, origin);
retval = res;
if (res != (loff_t)retval)
retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
}
fput_light(file, fput_needed);
bad:
return retval;
}
#ifdef __ARCH_WANT_SYS_LLSEEK
asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
unsigned long offset_low, loff_t __user * result,
unsigned int origin)
{
int retval;
struct file * file;
loff_t offset;
int fput_needed;
retval = -EBADF;
file = fget_light(fd, &fput_needed);
if (!file)
goto bad;
retval = -EINVAL;
if (origin > 2)
goto out_putf;
offset = vfs_llseek(file, ((loff_t) offset_high << 32) | offset_low,
origin);
retval = (int)offset;
if (offset >= 0) {
retval = -EFAULT;
if (!copy_to_user(result, &offset, sizeof(offset)))
retval = 0;
}
out_putf:
fput_light(file, fput_needed);
bad:
return retval;
}
#endif
int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
{
struct inode *inode;
loff_t pos;
if (unlikely(count > file->f_maxcount))
goto Einval;
pos = *ppos;
if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
goto Einval;
inode = file->f_dentry->d_inode;
if (inode->i_flock && MANDATORY_LOCK(inode))
return locks_mandatory_area(read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE, inode, file, pos, count);
return 0;
Einval:
return -EINVAL;
}
ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
struct kiocb kiocb;
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
kiocb.ki_pos = *ppos;
ret = filp->f_op->aio_read(&kiocb, buf, len, kiocb.ki_pos);
if (-EIOCBQUEUED == ret)
ret = wait_on_sync_kiocb(&kiocb);
*ppos = kiocb.ki_pos;
return ret;
}
EXPORT_SYMBOL(do_sync_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_op || (!file->f_op->read && !file->f_op->aio_read))
return -EINVAL;
if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
return -EFAULT;
ret = rw_verify_area(READ, file, pos, count);
if (!ret) {
ret = security_file_permission (file, MAY_READ);
if (!ret) {
if (file->f_op->read)
ret = file->f_op->read(file, buf, count, pos);
else
ret = do_sync_read(file, buf, count, pos);
if (ret > 0) {
dnotify_parent(file->f_dentry, DN_ACCESS);
current->rchar += ret;
}
current->syscr++;
}
}
return ret;
}
EXPORT_SYMBOL(vfs_read);
ssize_t do_sync_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
{
struct kiocb kiocb;
ssize_t ret;
init_sync_kiocb(&kiocb, filp);
kiocb.ki_pos = *ppos;
ret = filp->f_op->aio_write(&kiocb, buf, len, kiocb.ki_pos);
if (-EIOCBQUEUED == ret)
ret = wait_on_sync_kiocb(&kiocb);
*ppos = kiocb.ki_pos;
return ret;
}
EXPORT_SYMBOL(do_sync_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_op || (!file->f_op->write && !file->f_op->aio_write))
return -EINVAL;
if (unlikely(!access_ok(VERIFY_READ, buf, count)))
return -EFAULT;
ret = rw_verify_area(WRITE, file, pos, count);
if (!ret) {
ret = security_file_permission (file, MAY_WRITE);
if (!ret) {
if (file->f_op->write)
ret = file->f_op->write(file, buf, count, pos);
else
ret = do_sync_write(file, buf, count, pos);
if (ret > 0) {
dnotify_parent(file->f_dentry, DN_MODIFY);
current->wchar += ret;
}
current->syscw++;
}
}
return ret;
}
EXPORT_SYMBOL(vfs_write);
static inline loff_t file_pos_read(struct file *file)
{
return file->f_pos;
}
static inline void file_pos_write(struct file *file, loff_t pos)
{
file->f_pos = pos;
}
asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
{
struct file *file;
ssize_t ret = -EBADF;
int fput_needed;
file = fget_light(fd, &fput_needed);
if (file) {
loff_t pos = file_pos_read(file);
ret = vfs_read(file, buf, count, &pos);
file_pos_write(file, pos);
fput_light(file, fput_needed);
}
return ret;
}
EXPORT_SYMBOL_GPL(sys_read);
asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
{
struct file *file;
ssize_t ret = -EBADF;
int fput_needed;
file = fget_light(fd, &fput_needed);
if (file) {
loff_t pos = file_pos_read(file);
ret = vfs_write(file, buf, count, &pos);
file_pos_write(file, pos);
fput_light(file, fput_needed);
}
return ret;
}
asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
size_t count, loff_t pos)
{
struct file *file;
ssize_t ret = -EBADF;
int fput_needed;
if (pos < 0)
return -EINVAL;
file = fget_light(fd, &fput_needed);
if (file) {
ret = -ESPIPE;
if (file->f_mode & FMODE_PREAD)
ret = vfs_read(file, buf, count, &pos);
fput_light(file, fput_needed);
}
return ret;
}
asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
size_t count, loff_t pos)
{
struct file *file;
ssize_t ret = -EBADF;
int fput_needed;
if (pos < 0)
return -EINVAL;
file = fget_light(fd, &fput_needed);
if (file) {
ret = -ESPIPE;
if (file->f_mode & FMODE_PWRITE)
ret = vfs_write(file, buf, count, &pos);
fput_light(file, fput_needed);
}
return ret;
}
/*
* Reduce an iovec's length in-place. Return the resulting number of segments
*/
unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
{
unsigned long seg = 0;
size_t len = 0;
while (seg < nr_segs) {
seg++;
if (len + iov->iov_len >= to) {
iov->iov_len = to - len;
break;
}
len += iov->iov_len;
iov++;
}
return seg;
}
EXPORT_SYMBOL(iov_shorten);
/* A write operation does a read from user space and vice versa */
#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
static ssize_t do_readv_writev(int type, struct file *file,
const struct iovec __user * uvector,
unsigned long nr_segs, loff_t *pos)
{
typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
typedef ssize_t (*iov_fn_t)(struct file *, const struct iovec *, unsigned long, loff_t *);
size_t tot_len;
struct iovec iovstack[UIO_FASTIOV];
struct iovec *iov=iovstack, *vector;
ssize_t ret;
int seg;
io_fn_t fn;
iov_fn_t fnv;
/*
* 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...
*/
ret = 0;
if (nr_segs == 0)
goto out;
/*
* First get the "struct iovec" from user memory and
* verify all the pointers
*/
ret = -EINVAL;
if ((nr_segs > UIO_MAXIOV) || (nr_segs <= 0))
goto out;
if (!file->f_op)
goto out;
if (nr_segs > UIO_FASTIOV) {
ret = -ENOMEM;
iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
if (!iov)
goto out;
}
ret = -EFAULT;
if (copy_from_user(iov, 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. The total length is fitting an ssize_t
*
* Be careful here because iov_len is a size_t not an ssize_t
*/
tot_len = 0;
ret = -EINVAL;
for (seg = 0; seg < nr_segs; seg++) {
void __user *buf = iov[seg].iov_base;
ssize_t len = (ssize_t)iov[seg].iov_len;
if (len < 0) /* size_t not fitting an ssize_t .. */
goto out;
if (unlikely(!access_ok(vrfy_dir(type), buf, len)))
goto Efault;
tot_len += len;
if ((ssize_t)tot_len < 0) /* maths overflow on the ssize_t */
goto out;
}
if (tot_len == 0) {
ret = 0;
goto out;
}
ret = rw_verify_area(type, file, pos, tot_len);
if (ret)
goto out;
fnv = NULL;
if (type == READ) {
fn = file->f_op->read;
fnv = file->f_op->readv;
} else {
fn = (io_fn_t)file->f_op->write;
fnv = file->f_op->writev;
}
if (fnv) {
ret = fnv(file, iov, nr_segs, pos);
goto out;
}
/* Do it by hand, with file-ops */
ret = 0;
vector = iov;
while (nr_segs > 0) {
void __user * base;
size_t len;
ssize_t nr;
base = vector->iov_base;
len = vector->iov_len;
vector++;
nr_segs--;
nr = fn(file, base, len, pos);
if (nr < 0) {
if (!ret) ret = nr;
break;
}
ret += nr;
if (nr != len)
break;
}
out:
if (iov != iovstack)
kfree(iov);
if ((ret + (type == READ)) > 0)
dnotify_parent(file->f_dentry,
(type == READ) ? DN_ACCESS : DN_MODIFY);
return ret;
Efault:
ret = -EFAULT;
goto out;
}
ssize_t vfs_readv(struct file *file, const struct iovec __user *vec,
unsigned long vlen, loff_t *pos)
{
if (!(file->f_mode & FMODE_READ))
return -EBADF;
if (!file->f_op || (!file->f_op->readv && !file->f_op->read))
return -EINVAL;
return do_readv_writev(READ, file, vec, vlen, pos);
}
EXPORT_SYMBOL(vfs_readv);
ssize_t vfs_writev(struct file *file, const struct iovec __user *vec,
unsigned long vlen, loff_t *pos)
{
if (!(file->f_mode & FMODE_WRITE))
return -EBADF;
if (!file->f_op || (!file->f_op->writev && !file->f_op->write))
return -EINVAL;
return do_readv_writev(WRITE, file, vec, vlen, pos);
}
EXPORT_SYMBOL(vfs_writev);
asmlinkage ssize_t
sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
{
struct file *file;
ssize_t ret = -EBADF;
int fput_needed;
file = fget_light(fd, &fput_needed);
if (file) {
loff_t pos = file_pos_read(file);
ret = vfs_readv(file, vec, vlen, &pos);
file_pos_write(file, pos);
fput_light(file, fput_needed);
}
if (ret > 0)
current->rchar += ret;
current->syscr++;
return ret;
}
asmlinkage ssize_t
sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
{
struct file *file;
ssize_t ret = -EBADF;
int fput_needed;
file = fget_light(fd, &fput_needed);
if (file) {
loff_t pos = file_pos_read(file);
ret = vfs_writev(file, vec, vlen, &pos);
file_pos_write(file, pos);
fput_light(file, fput_needed);
}
if (ret > 0)
current->wchar += ret;
current->syscw++;
return ret;
}
static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
size_t count, loff_t max)
{
struct file * in_file, * out_file;
struct inode * in_inode, * out_inode;
loff_t pos;
ssize_t retval;
int fput_needed_in, fput_needed_out;
/*
* Get input file, and verify that it is ok..
*/
retval = -EBADF;
in_file = fget_light(in_fd, &fput_needed_in);
if (!in_file)
goto out;
if (!(in_file->f_mode & FMODE_READ))
goto fput_in;
retval = -EINVAL;
in_inode = in_file->f_dentry->d_inode;
if (!in_inode)
goto fput_in;
if (!in_file->f_op || !in_file->f_op->sendfile)
goto fput_in;
retval = -ESPIPE;
if (!ppos)
ppos = &in_file->f_pos;
else
if (!(in_file->f_mode & FMODE_PREAD))
goto fput_in;
retval = rw_verify_area(READ, in_file, ppos, count);
if (retval)
goto fput_in;
retval = security_file_permission (in_file, MAY_READ);
if (retval)
goto fput_in;
/*
* Get output file, and verify that it is ok..
*/
retval = -EBADF;
out_file = fget_light(out_fd, &fput_needed_out);
if (!out_file)
goto fput_in;
if (!(out_file->f_mode & FMODE_WRITE))
goto fput_out;
retval = -EINVAL;
if (!out_file->f_op || !out_file->f_op->sendpage)
goto fput_out;
out_inode = out_file->f_dentry->d_inode;
retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
if (retval)
goto fput_out;
retval = security_file_permission (out_file, MAY_WRITE);
if (retval)
goto fput_out;
if (!max)
max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
pos = *ppos;
retval = -EINVAL;
if (unlikely(pos < 0))
goto fput_out;
if (unlikely(pos + count > max)) {
retval = -EOVERFLOW;
if (pos >= max)
goto fput_out;
count = max - pos;
}
retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
if (retval > 0) {
current->rchar += retval;
current->wchar += retval;
}
current->syscr++;
current->syscw++;
if (*ppos > max)
retval = -EOVERFLOW;
fput_out:
fput_light(out_file, fput_needed_out);
fput_in:
fput_light(in_file, fput_needed_in);
out:
return retval;
}
asmlinkage ssize_t sys_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);
}
asmlinkage ssize_t sys_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);
}
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