[net-next-2.6.git] / fs / read_write.c

/*
 *  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/fsnotify.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include "read_write.h"

#include <asm/uaccess.h>
#include <asm/unistd.h>

const 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;

	mutex_lock(&inode->i_mutex);
	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;
	}
	mutex_unlock(&inode->i_mutex);
	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

/*
 * rw_verify_area doesn't like huge counts. We limit
 * them to something that fits in "int" so that others
 * won't have to do range checks all the time.
 */
#define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)

int rw_verify_area(int read_write, struct file *file, loff_t *ppos, size_t count)
{
	struct inode *inode;
	loff_t pos;

	if (unlikely((ssize_t) count < 0))
		goto Einval;
	pos = *ppos;
	if (unlikely((pos < 0) || (loff_t) (pos + count) < 0))
		goto Einval;

	inode = file->f_dentry->d_inode;
	if (unlikely(inode->i_flock && MANDATORY_LOCK(inode))) {
		int retval = locks_mandatory_area(
			read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
			inode, file, pos, count);
		if (retval < 0)
			return retval;
	}
	return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;

Einval:
	return -EINVAL;
}

static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
{
	set_current_state(TASK_UNINTERRUPTIBLE);
	if (!kiocbIsKicked(iocb))
		schedule();
	else
		kiocbClearKicked(iocb);
	__set_current_state(TASK_RUNNING);
}

ssize_t do_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;
	ssize_t ret;

	init_sync_kiocb(&kiocb, filp);
	kiocb.ki_pos = *ppos;
	kiocb.ki_left = len;

	for (;;) {
		ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
		if (ret != -EIOCBRETRY)
			break;
		wait_on_retry_sync_kiocb(&kiocb);
	}

	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 >= 0) {
		count = 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) {
				fsnotify_access(file->f_dentry);
				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 iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
	struct kiocb kiocb;
	ssize_t ret;

	init_sync_kiocb(&kiocb, filp);
	kiocb.ki_pos = *ppos;
	kiocb.ki_left = len;

	for (;;) {
		ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
		if (ret != -EIOCBRETRY)
			break;
		wait_on_retry_sync_kiocb(&kiocb);
	}

	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 >= 0) {
		count = 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) {
				fsnotify_modify(file->f_dentry);
				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_UNUSED_SYMBOL(iov_shorten);  /*  June 2006  */

ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
		unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
{
	struct kiocb kiocb;
	ssize_t ret;

	init_sync_kiocb(&kiocb, filp);
	kiocb.ki_pos = *ppos;
	kiocb.ki_left = len;
	kiocb.ki_nbytes = len;

	for (;;) {
		ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
		if (ret != -EIOCBRETRY)
			break;
		wait_on_retry_sync_kiocb(&kiocb);
	}

	if (ret == -EIOCBQUEUED)
		ret = wait_on_sync_kiocb(&kiocb);
	*ppos = kiocb.ki_pos;
	return ret;
}

/* Do it by hand, with file-ops */
ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
		unsigned long nr_segs, loff_t *ppos, io_fn_t fn)
{
	struct iovec *vector = iov;
	ssize_t ret = 0;

	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(filp, base, len, ppos);

		if (nr < 0) {
			if (!ret)
				ret = nr;
			break;
		}
		ret += nr;
		if (nr != len)
			break;
	}

	return ret;
}

/* 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)
{
	size_t tot_len;
	struct iovec iovstack[UIO_FASTIOV];
	struct iovec *iov = iovstack;
	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)
		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 < 0)
		goto out;
	ret = security_file_permission(file, type == READ ? MAY_READ : MAY_WRITE);
	if (ret)
		goto out;

	fnv = NULL;
	if (type == READ) {
		fn = file->f_op->read;
		fnv = file->f_op->aio_read;
	} else {
		fn = (io_fn_t)file->f_op->write;
		fnv = file->f_op->aio_write;
	}

	if (fnv)
		ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
						pos, fnv);
	else
		ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);

out:
	if (iov != iovstack)
		kfree(iov);
	if ((ret + (type == READ)) > 0) {
		if (type == READ)
			fsnotify_access(file->f_dentry);
		else
			fsnotify_modify(file->f_dentry);
	}
	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->aio_read && !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->aio_write && !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 < 0)
		goto fput_in;
	count = retval;

	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 < 0)
		goto fput_out;
	count = retval;

	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);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/read_write.c
	3	*
	4	* Copyright (C) 1991, 1992 Linus Torvalds
	5	*/
	6
	7	#include <linux/slab.h>
	8	#include <linux/stat.h>
	9	#include <linux/fcntl.h>
	10	#include <linux/file.h>
	11	#include <linux/uio.h>
	12	#include <linux/smp_lock.h>
0eeca283	13	#include <linux/fsnotify.h>
1da177e4 LT	14	#include <linux/security.h>
	15	#include <linux/module.h>
	16	#include <linux/syscalls.h>
e28cc715	17	#include <linux/pagemap.h>
ee0b3e67	18	#include "read_write.h"
1da177e4 LT	19
	20	#include <asm/uaccess.h>
	21	#include <asm/unistd.h>
	22
4b6f5d20	23	const struct file_operations generic_ro_fops = {
1da177e4 LT	24	.llseek = generic_file_llseek,
	25	.read = generic_file_read,
	26	.mmap = generic_file_readonly_mmap,
	27	.sendfile = generic_file_sendfile,
	28	};
	29
	30	EXPORT_SYMBOL(generic_ro_fops);
	31
	32	loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
	33	{
	34	long long retval;
	35	struct inode *inode = file->f_mapping->host;
	36
1b1dcc1b	37	mutex_lock(&inode->i_mutex);
1da177e4 LT	38	switch (origin) {
	39	case 2:
	40	offset += inode->i_size;
	41	break;
	42	case 1:
	43	offset += file->f_pos;
	44	}
	45	retval = -EINVAL;
	46	if (offset>=0 && offset<=inode->i_sb->s_maxbytes) {
	47	if (offset != file->f_pos) {
	48	file->f_pos = offset;
	49	file->f_version = 0;
	50	}
	51	retval = offset;
	52	}
1b1dcc1b	53	mutex_unlock(&inode->i_mutex);
1da177e4 LT	54	return retval;
	55	}
	56
	57	EXPORT_SYMBOL(generic_file_llseek);
	58
	59	loff_t remote_llseek(struct file *file, loff_t offset, int origin)
	60	{
	61	long long retval;
	62
	63	lock_kernel();
	64	switch (origin) {
	65	case 2:
	66	offset += i_size_read(file->f_dentry->d_inode);
	67	break;
	68	case 1:
	69	offset += file->f_pos;
	70	}
	71	retval = -EINVAL;
	72	if (offset>=0 && offset<=file->f_dentry->d_inode->i_sb->s_maxbytes) {
	73	if (offset != file->f_pos) {
	74	file->f_pos = offset;
	75	file->f_version = 0;
	76	}
	77	retval = offset;
	78	}
	79	unlock_kernel();
	80	return retval;
	81	}
	82	EXPORT_SYMBOL(remote_llseek);
	83
	84	loff_t no_llseek(struct file *file, loff_t offset, int origin)
	85	{
	86	return -ESPIPE;
	87	}
	88	EXPORT_SYMBOL(no_llseek);
	89
	90	loff_t default_llseek(struct file *file, loff_t offset, int origin)
	91	{
	92	long long retval;
	93
	94	lock_kernel();
	95	switch (origin) {
	96	case 2:
	97	offset += i_size_read(file->f_dentry->d_inode);
	98	break;
	99	case 1:
	100	offset += file->f_pos;
	101	}
	102	retval = -EINVAL;
	103	if (offset >= 0) {
	104	if (offset != file->f_pos) {
	105	file->f_pos = offset;
	106	file->f_version = 0;
	107	}
	108	retval = offset;
	109	}
	110	unlock_kernel();
	111	return retval;
	112	}
	113	EXPORT_SYMBOL(default_llseek);
	114
	115	loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
	116	{
	117	loff_t (fn)(struct file , loff_t, int);
118
119	fn = no_llseek;
120	if (file->f_mode & FMODE_LSEEK) {
121	fn = default_llseek;
122	if (file->f_op && file->f_op->llseek)
123	fn = file->f_op->llseek;
124	}
125	return fn(file, offset, origin);
126	}
127	EXPORT_SYMBOL(vfs_llseek);
128
129	asmlinkage off_t sys_lseek(unsigned int fd, off_t offset, unsigned int origin)
130	{
131	off_t retval;
132	struct file * file;
133	int fput_needed;
134
135	retval = -EBADF;
136	file = fget_light(fd, &fput_needed);
137	if (!file)
138	goto bad;
139
140	retval = -EINVAL;
141	if (origin <= 2) {
142	loff_t res = vfs_llseek(file, offset, origin);
143	retval = res;
144	if (res != (loff_t)retval)
145	retval = -EOVERFLOW; /* LFS: should only happen on 32 bit platforms */
146	}
147	fput_light(file, fput_needed);
148	bad:
149	return retval;
150	}
151
152	#ifdef __ARCH_WANT_SYS_LLSEEK
153	asmlinkage long sys_llseek(unsigned int fd, unsigned long offset_high,
154	unsigned long offset_low, loff_t __user * result,
155	unsigned int origin)
156	{
157	int retval;
158	struct file * file;
159	loff_t offset;
160	int fput_needed;
161
162	retval = -EBADF;
163	file = fget_light(fd, &fput_needed);
164	if (!file)
165	goto bad;
166
167	retval = -EINVAL;
168	if (origin > 2)
169	goto out_putf;
170
171	offset = vfs_llseek(file, ((loff_t) offset_high << 32) \| offset_low,
172	origin);
173
174	retval = (int)offset;
175	if (offset >= 0) {
176	retval = -EFAULT;
177	if (!copy_to_user(result, &offset, sizeof(offset)))
178	retval = 0;
179	}
180	out_putf:
181	fput_light(file, fput_needed);
182	bad:
183	return retval;
184	}
185	#endif
186
e28cc715 LT	187	/*
	188	* rw_verify_area doesn't like huge counts. We limit
	189	* them to something that fits in "int" so that others
	190	* won't have to do range checks all the time.
	191	*/
	192	#define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
1da177e4 LT	193
	194	int rw_verify_area(int read_write, struct file file, loff_t ppos, size_t count)
	195	{
	196	struct inode *inode;
	197	loff_t pos;
	198
e28cc715	199	if (unlikely((ssize_t) count < 0))
1da177e4 LT	200	goto Einval;
	201	pos = *ppos;
	202	if (unlikely((pos < 0) \|\| (loff_t) (pos + count) < 0))
	203	goto Einval;
	204
	205	inode = file->f_dentry->d_inode;
49570e9b	206	if (unlikely(inode->i_flock && MANDATORY_LOCK(inode))) {
e28cc715 LT	207	int retval = locks_mandatory_area(
	208	read_write == READ ? FLOCK_VERIFY_READ : FLOCK_VERIFY_WRITE,
	209	inode, file, pos, count);
	210	if (retval < 0)
	211	return retval;
	212	}
	213	return count > MAX_RW_COUNT ? MAX_RW_COUNT : count;
1da177e4 LT	214
	215	Einval:
	216	return -EINVAL;
	217	}
	218
63e68809 BL	219	static void wait_on_retry_sync_kiocb(struct kiocb *iocb)
	220	{
	221	set_current_state(TASK_UNINTERRUPTIBLE);
	222	if (!kiocbIsKicked(iocb))
	223	schedule();
	224	else
	225	kiocbClearKicked(iocb);
	226	__set_current_state(TASK_RUNNING);
	227	}
	228
1da177e4 LT	229	ssize_t do_sync_read(struct file filp, char __user buf, size_t len, loff_t *ppos)
1da177e4 LT	230	{
027445c3	231	struct iovec iov = { .iov_base = buf, .iov_len = len };
1da177e4 LT	232	struct kiocb kiocb;
	233	ssize_t ret;
	234
	235	init_sync_kiocb(&kiocb, filp);
	236	kiocb.ki_pos = *ppos;
027445c3 BP	237	kiocb.ki_left = len;
	238
	239	for (;;) {
	240	ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
	241	if (ret != -EIOCBRETRY)
	242	break;
63e68809	243	wait_on_retry_sync_kiocb(&kiocb);
027445c3	244	}
63e68809	245
1da177e4 LT	246	if (-EIOCBQUEUED == ret)
	247	ret = wait_on_sync_kiocb(&kiocb);
	248	*ppos = kiocb.ki_pos;
	249	return ret;
	250	}
	251
	252	EXPORT_SYMBOL(do_sync_read);
	253
	254	ssize_t vfs_read(struct file file, char __user buf, size_t count, loff_t *pos)
	255	{
	256	ssize_t ret;
	257
	258	if (!(file->f_mode & FMODE_READ))
	259	return -EBADF;
	260	if (!file->f_op \|\| (!file->f_op->read && !file->f_op->aio_read))
	261	return -EINVAL;
	262	if (unlikely(!access_ok(VERIFY_WRITE, buf, count)))
	263	return -EFAULT;
	264
	265	ret = rw_verify_area(READ, file, pos, count);
e28cc715 LT	266	if (ret >= 0) {
e28cc715 LT	267	count = ret;
1da177e4 LT	268	ret = security_file_permission (file, MAY_READ);
	269	if (!ret) {
	270	if (file->f_op->read)
	271	ret = file->f_op->read(file, buf, count, pos);
	272	else
	273	ret = do_sync_read(file, buf, count, pos);
	274	if (ret > 0) {
0eeca283	275	fsnotify_access(file->f_dentry);
1da177e4 LT	276	current->rchar += ret;
	277	}
	278	current->syscr++;
	279	}
	280	}
	281
	282	return ret;
	283	}
	284
	285	EXPORT_SYMBOL(vfs_read);
	286
	287	ssize_t do_sync_write(struct file filp, const char __user buf, size_t len, loff_t *ppos)
	288	{
027445c3	289	struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = len };
1da177e4 LT	290	struct kiocb kiocb;
	291	ssize_t ret;
	292
	293	init_sync_kiocb(&kiocb, filp);
	294	kiocb.ki_pos = *ppos;
027445c3 BP	295	kiocb.ki_left = len;
	296
	297	for (;;) {
	298	ret = filp->f_op->aio_write(&kiocb, &iov, 1, kiocb.ki_pos);
	299	if (ret != -EIOCBRETRY)
	300	break;
63e68809	301	wait_on_retry_sync_kiocb(&kiocb);
027445c3	302	}
63e68809	303
1da177e4 LT	304	if (-EIOCBQUEUED == ret)
	305	ret = wait_on_sync_kiocb(&kiocb);
	306	*ppos = kiocb.ki_pos;
	307	return ret;
	308	}
	309
	310	EXPORT_SYMBOL(do_sync_write);
	311
	312	ssize_t vfs_write(struct file file, const char __user buf, size_t count, loff_t *pos)
	313	{
	314	ssize_t ret;
	315
	316	if (!(file->f_mode & FMODE_WRITE))
	317	return -EBADF;
	318	if (!file->f_op \|\| (!file->f_op->write && !file->f_op->aio_write))
	319	return -EINVAL;
	320	if (unlikely(!access_ok(VERIFY_READ, buf, count)))
	321	return -EFAULT;
	322
	323	ret = rw_verify_area(WRITE, file, pos, count);
e28cc715 LT	324	if (ret >= 0) {
e28cc715 LT	325	count = ret;
1da177e4 LT	326	ret = security_file_permission (file, MAY_WRITE);
	327	if (!ret) {
	328	if (file->f_op->write)
	329	ret = file->f_op->write(file, buf, count, pos);
	330	else
	331	ret = do_sync_write(file, buf, count, pos);
	332	if (ret > 0) {
0eeca283	333	fsnotify_modify(file->f_dentry);
1da177e4 LT	334	current->wchar += ret;
	335	}
	336	current->syscw++;
	337	}
	338	}
	339
	340	return ret;
	341	}
	342
	343	EXPORT_SYMBOL(vfs_write);
	344
	345	static inline loff_t file_pos_read(struct file *file)
	346	{
	347	return file->f_pos;
	348	}
	349
	350	static inline void file_pos_write(struct file *file, loff_t pos)
	351	{
	352	file->f_pos = pos;
	353	}
	354
	355	asmlinkage ssize_t sys_read(unsigned int fd, char __user * buf, size_t count)
	356	{
	357	struct file *file;
	358	ssize_t ret = -EBADF;
	359	int fput_needed;
	360
	361	file = fget_light(fd, &fput_needed);
	362	if (file) {
	363	loff_t pos = file_pos_read(file);
	364	ret = vfs_read(file, buf, count, &pos);
	365	file_pos_write(file, pos);
	366	fput_light(file, fput_needed);
	367	}
	368
	369	return ret;
	370	}
	371	EXPORT_SYMBOL_GPL(sys_read);
	372
	373	asmlinkage ssize_t sys_write(unsigned int fd, const char __user * buf, size_t count)
	374	{
	375	struct file *file;
	376	ssize_t ret = -EBADF;
	377	int fput_needed;
	378
	379	file = fget_light(fd, &fput_needed);
	380	if (file) {
	381	loff_t pos = file_pos_read(file);
	382	ret = vfs_write(file, buf, count, &pos);
	383	file_pos_write(file, pos);
	384	fput_light(file, fput_needed);
	385	}
	386
	387	return ret;
	388	}
	389
	390	asmlinkage ssize_t sys_pread64(unsigned int fd, char __user *buf,
	391	size_t count, loff_t pos)
	392	{
	393	struct file *file;
	394	ssize_t ret = -EBADF;
	395	int fput_needed;
	396
	397	if (pos < 0)
398	return -EINVAL;
399
400	file = fget_light(fd, &fput_needed);
401	if (file) {
402	ret = -ESPIPE;
403	if (file->f_mode & FMODE_PREAD)
404	ret = vfs_read(file, buf, count, &pos);
405	fput_light(file, fput_needed);
406	}
407
408	return ret;
409	}
410
411	asmlinkage ssize_t sys_pwrite64(unsigned int fd, const char __user *buf,
412	size_t count, loff_t pos)
413	{
414	struct file *file;
415	ssize_t ret = -EBADF;
416	int fput_needed;
417
418	if (pos < 0)
419	return -EINVAL;
420
421	file = fget_light(fd, &fput_needed);
422	if (file) {
423	ret = -ESPIPE;
424	if (file->f_mode & FMODE_PWRITE)
425	ret = vfs_write(file, buf, count, &pos);
426	fput_light(file, fput_needed);
427	}
428
429	return ret;
430	}
431
432	/*
433	* Reduce an iovec's length in-place. Return the resulting number of segments
434	*/
435	unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
436	{
437	unsigned long seg = 0;
438	size_t len = 0;
439
440	while (seg < nr_segs) {
441	seg++;
442	if (len + iov->iov_len >= to) {
443	iov->iov_len = to - len;
444	break;
445	}
446	len += iov->iov_len;
447	iov++;
448	}
449	return seg;
450	}
451
69c3a5b8	452	EXPORT_UNUSED_SYMBOL(iov_shorten); /* June 2006 */
1da177e4	453
ee0b3e67 BP	454	ssize_t do_sync_readv_writev(struct file filp, const struct iovec iov,
	455	unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
	456	{
	457	struct kiocb kiocb;
	458	ssize_t ret;
	459
	460	init_sync_kiocb(&kiocb, filp);
	461	kiocb.ki_pos = *ppos;
	462	kiocb.ki_left = len;
	463	kiocb.ki_nbytes = len;
	464
	465	for (;;) {
	466	ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
	467	if (ret != -EIOCBRETRY)
	468	break;
	469	wait_on_retry_sync_kiocb(&kiocb);
	470	}
	471
	472	if (ret == -EIOCBQUEUED)
	473	ret = wait_on_sync_kiocb(&kiocb);
	474	*ppos = kiocb.ki_pos;
	475	return ret;
	476	}
	477
	478	/* Do it by hand, with file-ops */
	479	ssize_t do_loop_readv_writev(struct file filp, struct iovec iov,
	480	unsigned long nr_segs, loff_t *ppos, io_fn_t fn)
	481	{
	482	struct iovec *vector = iov;
	483	ssize_t ret = 0;
	484
	485	while (nr_segs > 0) {
	486	void __user *base;
	487	size_t len;
	488	ssize_t nr;
	489
	490	base = vector->iov_base;
	491	len = vector->iov_len;
	492	vector++;
	493	nr_segs--;
	494
	495	nr = fn(filp, base, len, ppos);
	496
	497	if (nr < 0) {
	498	if (!ret)
	499	ret = nr;
	500	break;
	501	}
	502	ret += nr;
	503	if (nr != len)
	504	break;
	505	}
	506
	507	return ret;
	508	}
	509
1da177e4 LT	510	/* A write operation does a read from user space and vice versa */
	511	#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)
	512
	513	static ssize_t do_readv_writev(int type, struct file *file,
	514	const struct iovec __user * uvector,
	515	unsigned long nr_segs, loff_t *pos)
	516	{
1da177e4 LT	517	size_t tot_len;
1da177e4 LT	518	struct iovec iovstack[UIO_FASTIOV];
ee0b3e67	519	struct iovec *iov = iovstack;
1da177e4 LT	520	ssize_t ret;
	521	int seg;
	522	io_fn_t fn;
	523	iov_fn_t fnv;
	524
	525	/*
	526	* SuS says "The readv() function may fail if the iovcnt argument
	527	* was less than or equal to 0, or greater than {IOV_MAX}. Linux has
	528	* traditionally returned zero for zero segments, so...
	529	*/
	530	ret = 0;
	531	if (nr_segs == 0)
	532	goto out;
	533
	534	/*
	535	* First get the "struct iovec" from user memory and
	536	* verify all the pointers
	537	*/
	538	ret = -EINVAL;
6cc6b122	539	if (nr_segs > UIO_MAXIOV)
1da177e4 LT	540	goto out;
	541	if (!file->f_op)
	542	goto out;
	543	if (nr_segs > UIO_FASTIOV) {
	544	ret = -ENOMEM;
	545	iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
	546	if (!iov)
	547	goto out;
	548	}
	549	ret = -EFAULT;
	550	if (copy_from_user(iov, uvector, nr_segssizeof(uvector)))
	551	goto out;
	552
	553	/*
	554	* Single unix specification:
	555	* We should -EINVAL if an element length is not >= 0 and fitting an
	556	* ssize_t. The total length is fitting an ssize_t
	557	*
	558	* Be careful here because iov_len is a size_t not an ssize_t
	559	*/
	560	tot_len = 0;
	561	ret = -EINVAL;
	562	for (seg = 0; seg < nr_segs; seg++) {
	563	void __user *buf = iov[seg].iov_base;
	564	ssize_t len = (ssize_t)iov[seg].iov_len;
	565
1da177e4 LT	566	if (len < 0) /* size_t not fitting an ssize_t .. */
1da177e4 LT	567	goto out;
1f08ad02 DH	568	if (unlikely(!access_ok(vrfy_dir(type), buf, len)))
1f08ad02 DH	569	goto Efault;
1da177e4 LT	570	tot_len += len;
	571	if ((ssize_t)tot_len < 0) /* maths overflow on the ssize_t */
	572	goto out;
	573	}
	574	if (tot_len == 0) {
	575	ret = 0;
	576	goto out;
	577	}
	578
	579	ret = rw_verify_area(type, file, pos, tot_len);
e28cc715	580	if (ret < 0)
411b67b4 KB	581	goto out;
411b67b4 KB	582	ret = security_file_permission(file, type == READ ? MAY_READ : MAY_WRITE);
1da177e4 LT	583	if (ret)
	584	goto out;
	585
	586	fnv = NULL;
	587	if (type == READ) {
	588	fn = file->f_op->read;
ee0b3e67	589	fnv = file->f_op->aio_read;
1da177e4 LT	590	} else {
1da177e4 LT	591	fn = (io_fn_t)file->f_op->write;
ee0b3e67	592	fnv = file->f_op->aio_write;
1da177e4 LT	593	}
1da177e4 LT	594
ee0b3e67 BP	595	if (fnv)
	596	ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
	597	pos, fnv);
	598	else
	599	ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
1da177e4	600
1da177e4 LT	601	out:
	602	if (iov != iovstack)
	603	kfree(iov);
0eeca283 RL	604	if ((ret + (type == READ)) > 0) {
	605	if (type == READ)
	606	fsnotify_access(file->f_dentry);
	607	else
	608	fsnotify_modify(file->f_dentry);
	609	}
1da177e4 LT	610	return ret;
	611	Efault:
	612	ret = -EFAULT;
	613	goto out;
	614	}
	615
	616	ssize_t vfs_readv(struct file file, const struct iovec __user vec,
	617	unsigned long vlen, loff_t *pos)
	618	{
	619	if (!(file->f_mode & FMODE_READ))
	620	return -EBADF;
ee0b3e67	621	if (!file->f_op \|\| (!file->f_op->aio_read && !file->f_op->read))
1da177e4 LT	622	return -EINVAL;
	623
	624	return do_readv_writev(READ, file, vec, vlen, pos);
	625	}
	626
	627	EXPORT_SYMBOL(vfs_readv);
	628
	629	ssize_t vfs_writev(struct file file, const struct iovec __user vec,
	630	unsigned long vlen, loff_t *pos)
	631	{
	632	if (!(file->f_mode & FMODE_WRITE))
	633	return -EBADF;
ee0b3e67	634	if (!file->f_op \|\| (!file->f_op->aio_write && !file->f_op->write))
1da177e4 LT	635	return -EINVAL;
	636
	637	return do_readv_writev(WRITE, file, vec, vlen, pos);
	638	}
	639
	640	EXPORT_SYMBOL(vfs_writev);
	641
	642	asmlinkage ssize_t
	643	sys_readv(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
	644	{
	645	struct file *file;
	646	ssize_t ret = -EBADF;
	647	int fput_needed;
	648
	649	file = fget_light(fd, &fput_needed);
	650	if (file) {
	651	loff_t pos = file_pos_read(file);
	652	ret = vfs_readv(file, vec, vlen, &pos);
	653	file_pos_write(file, pos);
	654	fput_light(file, fput_needed);
	655	}
	656
	657	if (ret > 0)
	658	current->rchar += ret;
	659	current->syscr++;
	660	return ret;
	661	}
	662
	663	asmlinkage ssize_t
	664	sys_writev(unsigned long fd, const struct iovec __user *vec, unsigned long vlen)
	665	{
	666	struct file *file;
	667	ssize_t ret = -EBADF;
	668	int fput_needed;
	669
	670	file = fget_light(fd, &fput_needed);
	671	if (file) {
	672	loff_t pos = file_pos_read(file);
	673	ret = vfs_writev(file, vec, vlen, &pos);
	674	file_pos_write(file, pos);
	675	fput_light(file, fput_needed);
	676	}
	677
	678	if (ret > 0)
	679	current->wchar += ret;
	680	current->syscw++;
	681	return ret;
	682	}
	683
	684	static ssize_t do_sendfile(int out_fd, int in_fd, loff_t *ppos,
	685	size_t count, loff_t max)
	686	{
	687	struct file * in_file, * out_file;
	688	struct inode * in_inode, * out_inode;
	689	loff_t pos;
	690	ssize_t retval;
	691	int fput_needed_in, fput_needed_out;
	692
	693	/*
	694	* Get input file, and verify that it is ok..
	695	*/
	696	retval = -EBADF;
	697	in_file = fget_light(in_fd, &fput_needed_in);
	698	if (!in_file)
699	goto out;
700	if (!(in_file->f_mode & FMODE_READ))
701	goto fput_in;
702	retval = -EINVAL;
703	in_inode = in_file->f_dentry->d_inode;
704	if (!in_inode)
705	goto fput_in;
706	if (!in_file->f_op \|\| !in_file->f_op->sendfile)
707	goto fput_in;
708	retval = -ESPIPE;
709	if (!ppos)
710	ppos = &in_file->f_pos;
711	else
712	if (!(in_file->f_mode & FMODE_PREAD))
713	goto fput_in;
714	retval = rw_verify_area(READ, in_file, ppos, count);
e28cc715	715	if (retval < 0)
1da177e4	716	goto fput_in;
e28cc715	717	count = retval;
1da177e4 LT	718
	719	retval = security_file_permission (in_file, MAY_READ);
	720	if (retval)
	721	goto fput_in;
	722
	723	/*
	724	* Get output file, and verify that it is ok..
	725	*/
	726	retval = -EBADF;
	727	out_file = fget_light(out_fd, &fput_needed_out);
	728	if (!out_file)
	729	goto fput_in;
	730	if (!(out_file->f_mode & FMODE_WRITE))
	731	goto fput_out;
	732	retval = -EINVAL;
	733	if (!out_file->f_op \|\| !out_file->f_op->sendpage)
	734	goto fput_out;
	735	out_inode = out_file->f_dentry->d_inode;
	736	retval = rw_verify_area(WRITE, out_file, &out_file->f_pos, count);
e28cc715	737	if (retval < 0)
1da177e4	738	goto fput_out;
e28cc715	739	count = retval;
1da177e4 LT	740
	741	retval = security_file_permission (out_file, MAY_WRITE);
	742	if (retval)
	743	goto fput_out;
	744
	745	if (!max)
	746	max = min(in_inode->i_sb->s_maxbytes, out_inode->i_sb->s_maxbytes);
	747
	748	pos = *ppos;
	749	retval = -EINVAL;
	750	if (unlikely(pos < 0))
	751	goto fput_out;
	752	if (unlikely(pos + count > max)) {
	753	retval = -EOVERFLOW;
	754	if (pos >= max)
	755	goto fput_out;
	756	count = max - pos;
	757	}
	758
	759	retval = in_file->f_op->sendfile(in_file, ppos, count, file_send_actor, out_file);
	760
	761	if (retval > 0) {
	762	current->rchar += retval;
	763	current->wchar += retval;
	764	}
	765	current->syscr++;
	766	current->syscw++;
	767
	768	if (*ppos > max)
	769	retval = -EOVERFLOW;
	770
	771	fput_out:
	772	fput_light(out_file, fput_needed_out);
	773	fput_in:
	774	fput_light(in_file, fput_needed_in);
	775	out:
	776	return retval;
	777	}
	778
	779	asmlinkage ssize_t sys_sendfile(int out_fd, int in_fd, off_t __user *offset, size_t count)
	780	{
	781	loff_t pos;
	782	off_t off;
	783	ssize_t ret;
	784
	785	if (offset) {
	786	if (unlikely(get_user(off, offset)))
	787	return -EFAULT;
	788	pos = off;
	789	ret = do_sendfile(out_fd, in_fd, &pos, count, MAX_NON_LFS);
	790	if (unlikely(put_user(pos, offset)))
	791	return -EFAULT;
	792	return ret;
	793	}
	794
	795	return do_sendfile(out_fd, in_fd, NULL, count, 0);
	796	}
	797
	798	asmlinkage ssize_t sys_sendfile64(int out_fd, int in_fd, loff_t __user *offset, size_t count)
	799	{
	800	loff_t pos;
	801	ssize_t ret;
	802
	803	if (offset) {
804	if (unlikely(copy_from_user(&pos, offset, sizeof(loff_t))))
805	return -EFAULT;
806	ret = do_sendfile(out_fd, in_fd, &pos, count, 0);
807	if (unlikely(put_user(pos, offset)))
808	return -EFAULT;
809	return ret;
810	}
811
812	return do_sendfile(out_fd, in_fd, NULL, count, 0);
813	}