fs/compat.c

/*
 *  linux/fs/compat.c
 *
 *  Kernel compatibililty routines for e.g. 32 bit syscall support
 *  on 64 bit kernels.
 *
 *  Copyright (C) 2002 Stephen Rothwell, IBM Corporation
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License version 2 as
 *  published by the Free Software Foundation.
 */

#include <linux/linkage.h>
#include <linux/compat.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/fcntl.h>
#include <linux/namei.h>
#include <linux/file.h>
#include <linux/vfs.h>

#include <asm/uaccess.h>

/*
 * Not all architectures have sys_utime, so implement this in terms
 * of sys_utimes.
 */
asmlinkage long compat_sys_utime(char *filename, struct compat_utimbuf *t)
{
	struct timeval tv[2];

	if (t) {
		if (get_user(tv[0].tv_sec, &t->actime) ||
		    get_user(tv[1].tv_sec, &t->modtime))
			return -EFAULT;
		tv[0].tv_usec = 0;
		tv[1].tv_usec = 0;
	}
	return do_utimes(filename, t ? tv : NULL);
}


asmlinkage long compat_sys_newstat(char * filename,
		struct compat_stat *statbuf)
{
	struct kstat stat;
	int error = vfs_stat(filename, &stat);

	if (!error)
		error = cp_compat_stat(&stat, statbuf);
	return error;
}

asmlinkage long compat_sys_newlstat(char * filename,
		struct compat_stat *statbuf)
{
	struct kstat stat;
	int error = vfs_lstat(filename, &stat);

	if (!error)
		error = cp_compat_stat(&stat, statbuf);
	return error;
}

asmlinkage long compat_sys_newfstat(unsigned int fd,
		struct compat_stat * statbuf)
{
	struct kstat stat;
	int error = vfs_fstat(fd, &stat);

	if (!error)
		error = cp_compat_stat(&stat, statbuf);
	return error;
}

int get_compat_flock(struct flock *kfl, struct compat_flock *ufl)
{
	int err;

	if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)))
		return -EFAULT;

	err = __get_user(kfl->l_type, &ufl->l_type);
	err |= __get_user(kfl->l_whence, &ufl->l_whence);
	err |= __get_user(kfl->l_start, &ufl->l_start);
	err |= __get_user(kfl->l_len, &ufl->l_len);
	err |= __get_user(kfl->l_pid, &ufl->l_pid);
	return err;
}

int put_compat_flock(struct flock *kfl, struct compat_flock *ufl)
{
	int err;

	if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)))
		return -EFAULT;

	err = __put_user(kfl->l_type, &ufl->l_type);
	err |= __put_user(kfl->l_whence, &ufl->l_whence);
	err |= __put_user(kfl->l_start, &ufl->l_start);
	err |= __put_user(kfl->l_len, &ufl->l_len);
	err |= __put_user(kfl->l_pid, &ufl->l_pid);
	return err;
}

static int put_compat_statfs(struct compat_statfs *ubuf, struct statfs *kbuf)
{
	if (verify_area(VERIFY_WRITE, ubuf, sizeof(*ubuf)) ||
	    __put_user(kbuf->f_type, &ubuf->f_type) ||
	    __put_user(kbuf->f_bsize, &ubuf->f_bsize) ||
	    __put_user(kbuf->f_blocks, &ubuf->f_blocks) ||
	    __put_user(kbuf->f_bfree, &ubuf->f_bfree) ||
	    __put_user(kbuf->f_bavail, &ubuf->f_bavail) ||
	    __put_user(kbuf->f_files, &ubuf->f_files) ||
	    __put_user(kbuf->f_ffree, &ubuf->f_ffree) ||
	    __put_user(kbuf->f_namelen, &ubuf->f_namelen) ||
	    __put_user(kbuf->f_fsid.val[0], &ubuf->f_fsid.val[0]) ||
	    __put_user(kbuf->f_fsid.val[1], &ubuf->f_fsid.val[1]))
		return -EFAULT;
	return 0;
}

/*
 * The following statfs calls are copies of code from fs/open.c and
 * should be checked against those from time to time
 */
asmlinkage long compat_sys_statfs(const char *path, struct compat_statfs *buf)
{
	struct nameidata nd;
	int error;

	error = user_path_walk(path, &nd);
	if (!error) {
		struct statfs tmp;
		error = vfs_statfs(nd.dentry->d_inode->i_sb, &tmp);
		if (!error && put_compat_statfs(buf, &tmp))
			error = -EFAULT;
		path_release(&nd);
	}
	return error;
}

asmlinkage long compat_sys_fstatfs(unsigned int fd, struct compat_statfs *buf)
{
	struct file * file;
	struct statfs tmp;
	int error;

	error = -EBADF;
	file = fget(fd);
	if (!file)
		goto out;
	error = vfs_statfs(file->f_dentry->d_inode->i_sb, &tmp);
	if (!error && put_compat_statfs(buf, &tmp))
		error = -EFAULT;
	fput(file);
out:
	return error;
}