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
 *  Copyright (C) 1997-2000  Jakub Jelinek  (jakub@redhat.com)
 *  Copyright (C) 1998       Eddie C. Dost  (ecd@skynet.be)
 *  Copyright (C) 2001,2002  Andi Kleen, SuSE Labs 
 *  Copyright (C) 2003       Pavel Machek (pavel@suse.cz)
 *
 *  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/kernel.h>
#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/fdtable.h>
#include <linux/vfs.h>
#include <linux/ioctl.h>
#include <linux/init.h>
#include <linux/smb.h>
#include <linux/smb_mount.h>
#include <linux/ncp_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/smp_lock.h>
#include <linux/syscalls.h>
#include <linux/ctype.h>
#include <linux/module.h>
#include <linux/dirent.h>
#include <linux/fsnotify.h>
#include <linux/highuid.h>
#include <linux/sunrpc/svc.h>
#include <linux/nfsd/nfsd.h>
#include <linux/nfsd/syscall.h>
#include <linux/personality.h>
#include <linux/rwsem.h>
#include <linux/tsacct_kern.h>
#include <linux/security.h>
#include <linux/highmem.h>
#include <linux/signal.h>
#include <linux/poll.h>
#include <linux/mm.h>
#include <linux/eventpoll.h>

#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/ioctls.h>
#include "internal.h"

int compat_log = 1;

int compat_printk(const char *fmt, ...)
{
	va_list ap;
	int ret;
	if (!compat_log)
		return 0;
	va_start(ap, fmt);
	ret = vprintk(fmt, ap);
	va_end(ap);
	return ret;
}

#include "read_write.h"

/*
 * Not all architectures have sys_utime, so implement this in terms
 * of sys_utimes.
 */
asmlinkage long compat_sys_utime(char __user *filename, struct compat_utimbuf __user *t)
{
	struct timespec 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_nsec = 0;
		tv[1].tv_nsec = 0;
	}
	return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
}

asmlinkage long compat_sys_utimensat(unsigned int dfd, char __user *filename, struct compat_timespec __user *t, int flags)
{
	struct timespec tv[2];

	if  (t) {
		if (get_compat_timespec(&tv[0], &t[0]) ||
		    get_compat_timespec(&tv[1], &t[1]))
			return -EFAULT;

		if ((tv[0].tv_nsec == UTIME_OMIT || tv[0].tv_nsec == UTIME_NOW)
		    && tv[0].tv_sec != 0)
			return -EINVAL;
		if ((tv[1].tv_nsec == UTIME_OMIT || tv[1].tv_nsec == UTIME_NOW)
		    && tv[1].tv_sec != 0)
			return -EINVAL;

		if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
			return 0;
	}
	return do_utimes(dfd, filename, t ? tv : NULL, flags);
}

asmlinkage long compat_sys_futimesat(unsigned int dfd, char __user *filename, struct compat_timeval __user *t)
{
	struct timespec tv[2];

	if (t) {
		if (get_user(tv[0].tv_sec, &t[0].tv_sec) ||
		    get_user(tv[0].tv_nsec, &t[0].tv_usec) ||
		    get_user(tv[1].tv_sec, &t[1].tv_sec) ||
		    get_user(tv[1].tv_nsec, &t[1].tv_usec))
			return -EFAULT;
		if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 ||
		    tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0)
			return -EINVAL;
		tv[0].tv_nsec *= 1000;
		tv[1].tv_nsec *= 1000;
	}
	return do_utimes(dfd, filename, t ? tv : NULL, 0);
}

asmlinkage long compat_sys_utimes(char __user *filename, struct compat_timeval __user *t)
{
	return compat_sys_futimesat(AT_FDCWD, filename, t);
}

static int cp_compat_stat(struct kstat *stat, struct compat_stat __user *ubuf)
{
	compat_ino_t ino = stat->ino;
	typeof(ubuf->st_uid) uid = 0;
	typeof(ubuf->st_gid) gid = 0;
	int err;

	SET_UID(uid, stat->uid);
	SET_GID(gid, stat->gid);

	if ((u64) stat->size > MAX_NON_LFS ||
	    !old_valid_dev(stat->dev) ||
	    !old_valid_dev(stat->rdev))
		return -EOVERFLOW;
	if (sizeof(ino) < sizeof(stat->ino) && ino != stat->ino)
		return -EOVERFLOW;

	if (clear_user(ubuf, sizeof(*ubuf)))
		return -EFAULT;

	err  = __put_user(old_encode_dev(stat->dev), &ubuf->st_dev);
	err |= __put_user(ino, &ubuf->st_ino);
	err |= __put_user(stat->mode, &ubuf->st_mode);
	err |= __put_user(stat->nlink, &ubuf->st_nlink);
	err |= __put_user(uid, &ubuf->st_uid);
	err |= __put_user(gid, &ubuf->st_gid);
	err |= __put_user(old_encode_dev(stat->rdev), &ubuf->st_rdev);
	err |= __put_user(stat->size, &ubuf->st_size);
	err |= __put_user(stat->atime.tv_sec, &ubuf->st_atime);
	err |= __put_user(stat->atime.tv_nsec, &ubuf->st_atime_nsec);
	err |= __put_user(stat->mtime.tv_sec, &ubuf->st_mtime);
	err |= __put_user(stat->mtime.tv_nsec, &ubuf->st_mtime_nsec);
	err |= __put_user(stat->ctime.tv_sec, &ubuf->st_ctime);
	err |= __put_user(stat->ctime.tv_nsec, &ubuf->st_ctime_nsec);
	err |= __put_user(stat->blksize, &ubuf->st_blksize);
	err |= __put_user(stat->blocks, &ubuf->st_blocks);
	return err;
}

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

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

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

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

#ifndef __ARCH_WANT_STAT64
asmlinkage long compat_sys_newfstatat(unsigned int dfd, char __user *filename,
		struct compat_stat __user *statbuf, int flag)
{
	struct kstat stat;
	int error = -EINVAL;

	if ((flag & ~AT_SYMLINK_NOFOLLOW) != 0)
		goto out;

	if (flag & AT_SYMLINK_NOFOLLOW)
		error = vfs_lstat_fd(dfd, filename, &stat);
	else
		error = vfs_stat_fd(dfd, filename, &stat);

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

out:
	return error;
}
#endif

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

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

static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *kbuf)
{
	
	if (sizeof ubuf->f_blocks == 4) {
		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
		     kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
			return -EOVERFLOW;
		/* f_files and f_ffree may be -1; it's okay
		 * to stuff that into 32 bits */
		if (kbuf->f_files != 0xffffffffffffffffULL
		 && (kbuf->f_files & 0xffffffff00000000ULL))
			return -EOVERFLOW;
		if (kbuf->f_ffree != 0xffffffffffffffffULL
		 && (kbuf->f_ffree & 0xffffffff00000000ULL))
			return -EOVERFLOW;
	}
	if (!access_ok(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]) ||
	    __put_user(kbuf->f_frsize, &ubuf->f_frsize) ||
	    __put_user(0, &ubuf->f_spare[0]) || 
	    __put_user(0, &ubuf->f_spare[1]) || 
	    __put_user(0, &ubuf->f_spare[2]) || 
	    __put_user(0, &ubuf->f_spare[3]) || 
	    __put_user(0, &ubuf->f_spare[4]))
		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 __user *pathname, struct compat_statfs __user *buf)
{
	struct path path;
	int error;

	error = user_path(pathname, &path);
	if (!error) {
		struct kstatfs tmp;
		error = vfs_statfs(path.dentry, &tmp);
		if (!error)
			error = put_compat_statfs(buf, &tmp);
		path_put(&path);
	}
	return error;
}

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

	error = -EBADF;
	file = fget(fd);
	if (!file)
		goto out;
	error = vfs_statfs(file->f_path.dentry, &tmp);
	if (!error)
		error = put_compat_statfs(buf, &tmp);
	fput(file);
out:
	return error;
}

static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf)
{
	if (sizeof ubuf->f_blocks == 4) {
		if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
		     kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
			return -EOVERFLOW;
		/* f_files and f_ffree may be -1; it's okay
		 * to stuff that into 32 bits */
		if (kbuf->f_files != 0xffffffffffffffffULL
		 && (kbuf->f_files & 0xffffffff00000000ULL))
			return -EOVERFLOW;
		if (kbuf->f_ffree != 0xffffffffffffffffULL
		 && (kbuf->f_ffree & 0xffffffff00000000ULL))
			return -EOVERFLOW;
	}
	if (!access_ok(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]) ||
	    __put_user(kbuf->f_frsize, &ubuf->f_frsize))
		return -EFAULT;
	return 0;
}

asmlinkage long compat_sys_statfs64(const char __user *pathname, compat_size_t sz, struct compat_statfs64 __user *buf)
{
	struct path path;
	int error;

	if (sz != sizeof(*buf))
		return -EINVAL;

	error = user_path(pathname, &path);
	if (!error) {
		struct kstatfs tmp;
		error = vfs_statfs(path.dentry, &tmp);
		if (!error)
			error = put_compat_statfs64(buf, &tmp);
		path_put(&path);
	}
	return error;
}

asmlinkage long compat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user *buf)
{
	struct file * file;
	struct kstatfs tmp;
	int error;

	if (sz != sizeof(*buf))
		return -EINVAL;

	error = -EBADF;
	file = fget(fd);
	if (!file)
		goto out;
	error = vfs_statfs(file->f_path.dentry, &tmp);
	if (!error)
		error = put_compat_statfs64(buf, &tmp);
	fput(file);
out:
	return error;
}

static int get_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
{
	if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) ||
	    __get_user(kfl->l_type, &ufl->l_type) ||
	    __get_user(kfl->l_whence, &ufl->l_whence) ||
	    __get_user(kfl->l_start, &ufl->l_start) ||
	    __get_user(kfl->l_len, &ufl->l_len) ||
	    __get_user(kfl->l_pid, &ufl->l_pid))
		return -EFAULT;
	return 0;
}

static int put_compat_flock(struct flock *kfl, struct compat_flock __user *ufl)
{
	if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)) ||
	    __put_user(kfl->l_type, &ufl->l_type) ||
	    __put_user(kfl->l_whence, &ufl->l_whence) ||
	    __put_user(kfl->l_start, &ufl->l_start) ||
	    __put_user(kfl->l_len, &ufl->l_len) ||
	    __put_user(kfl->l_pid, &ufl->l_pid))
		return -EFAULT;
	return 0;
}

#ifndef HAVE_ARCH_GET_COMPAT_FLOCK64
static int get_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl)
{
	if (!access_ok(VERIFY_READ, ufl, sizeof(*ufl)) ||
	    __get_user(kfl->l_type, &ufl->l_type) ||
	    __get_user(kfl->l_whence, &ufl->l_whence) ||
	    __get_user(kfl->l_start, &ufl->l_start) ||
	    __get_user(kfl->l_len, &ufl->l_len) ||
	    __get_user(kfl->l_pid, &ufl->l_pid))
		return -EFAULT;
	return 0;
}
#endif

#ifndef HAVE_ARCH_PUT_COMPAT_FLOCK64
static int put_compat_flock64(struct flock *kfl, struct compat_flock64 __user *ufl)
{
	if (!access_ok(VERIFY_WRITE, ufl, sizeof(*ufl)) ||
	    __put_user(kfl->l_type, &ufl->l_type) ||
	    __put_user(kfl->l_whence, &ufl->l_whence) ||
	    __put_user(kfl->l_start, &ufl->l_start) ||
	    __put_user(kfl->l_len, &ufl->l_len) ||
	    __put_user(kfl->l_pid, &ufl->l_pid))
		return -EFAULT;
	return 0;
}
#endif

asmlinkage long compat_sys_fcntl64(unsigned int fd, unsigned int cmd,
		unsigned long arg)
{
	mm_segment_t old_fs;
	struct flock f;
	long ret;

	switch (cmd) {
	case F_GETLK:
	case F_SETLK:
	case F_SETLKW:
		ret = get_compat_flock(&f, compat_ptr(arg));
		if (ret != 0)
			break;
		old_fs = get_fs();
		set_fs(KERNEL_DS);
		ret = sys_fcntl(fd, cmd, (unsigned long)&f);
		set_fs(old_fs);
		if (cmd == F_GETLK && ret == 0) {
			/* GETLK was successfule and we need to return the data...
			 * but it needs to fit in the compat structure.
			 * l_start shouldn't be too big, unless the original
			 * start + end is greater than COMPAT_OFF_T_MAX, in which
			 * case the app was asking for trouble, so we return
			 * -EOVERFLOW in that case.
			 * l_len could be too big, in which case we just truncate it,
			 * and only allow the app to see that part of the conflicting
			 * lock that might make sense to it anyway
			 */

			if (f.l_start > COMPAT_OFF_T_MAX)
				ret = -EOVERFLOW;
			if (f.l_len > COMPAT_OFF_T_MAX)
				f.l_len = COMPAT_OFF_T_MAX;
			if (ret == 0)
				ret = put_compat_flock(&f, compat_ptr(arg));
		}
		break;

	case F_GETLK64:
	case F_SETLK64:
	case F_SETLKW64:
		ret = get_compat_flock64(&f, compat_ptr(arg));
		if (ret != 0)
			break;
		old_fs = get_fs();
		set_fs(KERNEL_DS);
		ret = sys_fcntl(fd, (cmd == F_GETLK64) ? F_GETLK :
				((cmd == F_SETLK64) ? F_SETLK : F_SETLKW),
				(unsigned long)&f);
		set_fs(old_fs);
		if (cmd == F_GETLK64 && ret == 0) {
			/* need to return lock information - see above for commentary */
			if (f.l_start > COMPAT_LOFF_T_MAX)
				ret = -EOVERFLOW;
			if (f.l_len > COMPAT_LOFF_T_MAX)
				f.l_len = COMPAT_LOFF_T_MAX;
			if (ret == 0)
				ret = put_compat_flock64(&f, compat_ptr(arg));
		}
		break;

	default:
		ret = sys_fcntl(fd, cmd, arg);
		break;
	}
	return ret;
}

asmlinkage long compat_sys_fcntl(unsigned int fd, unsigned int cmd,
		unsigned long arg)
{
	if ((cmd == F_GETLK64) || (cmd == F_SETLK64) || (cmd == F_SETLKW64))
		return -EINVAL;
	return compat_sys_fcntl64(fd, cmd, arg);
}

asmlinkage long
compat_sys_io_setup(unsigned nr_reqs, u32 __user *ctx32p)
{
	long ret;
	aio_context_t ctx64;

	mm_segment_t oldfs = get_fs();
	if (unlikely(get_user(ctx64, ctx32p)))
		return -EFAULT;

	set_fs(KERNEL_DS);
	/* The __user pointer cast is valid because of the set_fs() */
	ret = sys_io_setup(nr_reqs, (aio_context_t __user *) &ctx64);
	set_fs(oldfs);
	/* truncating is ok because it's a user address */
	if (!ret)
		ret = put_user((u32) ctx64, ctx32p);
	return ret;
}

asmlinkage long
compat_sys_io_getevents(aio_context_t ctx_id,
				 unsigned long min_nr,
				 unsigned long nr,
				 struct io_event __user *events,
				 struct compat_timespec __user *timeout)
{
	long ret;
	struct timespec t;
	struct timespec __user *ut = NULL;

	ret = -EFAULT;
	if (unlikely(!access_ok(VERIFY_WRITE, events, 
				nr * sizeof(struct io_event))))
		goto out;
	if (timeout) {
		if (get_compat_timespec(&t, timeout))
			goto out;

		ut = compat_alloc_user_space(sizeof(*ut));
		if (copy_to_user(ut, &t, sizeof(t)) )
			goto out;
	} 
	ret = sys_io_getevents(ctx_id, min_nr, nr, events, ut);
out:
	return ret;
}

static inline long
copy_iocb(long nr, u32 __user *ptr32, struct iocb __user * __user *ptr64)
{
	compat_uptr_t uptr;
	int i;

	for (i = 0; i < nr; ++i) {
		if (get_user(uptr, ptr32 + i))
			return -EFAULT;
		if (put_user(compat_ptr(uptr), ptr64 + i))
			return -EFAULT;
	}
	return 0;
}

#define MAX_AIO_SUBMITS 	(PAGE_SIZE/sizeof(struct iocb *))

asmlinkage long
compat_sys_io_submit(aio_context_t ctx_id, int nr, u32 __user *iocb)
{
	struct iocb __user * __user *iocb64; 
	long ret;

	if (unlikely(nr < 0))
		return -EINVAL;

	if (nr > MAX_AIO_SUBMITS)
		nr = MAX_AIO_SUBMITS;
	
	iocb64 = compat_alloc_user_space(nr * sizeof(*iocb64));
	ret = copy_iocb(nr, iocb, iocb64);
	if (!ret)
		ret = sys_io_submit(ctx_id, nr, iocb64);
	return ret;
}

struct compat_ncp_mount_data {
	compat_int_t version;
	compat_uint_t ncp_fd;
	__compat_uid_t mounted_uid;
	compat_pid_t wdog_pid;
	unsigned char mounted_vol[NCP_VOLNAME_LEN + 1];
	compat_uint_t time_out;
	compat_uint_t retry_count;
	compat_uint_t flags;
	__compat_uid_t uid;
	__compat_gid_t gid;
	compat_mode_t file_mode;
	compat_mode_t dir_mode;
};

struct compat_ncp_mount_data_v4 {
	compat_int_t version;
	compat_ulong_t flags;
	compat_ulong_t mounted_uid;
	compat_long_t wdog_pid;
	compat_uint_t ncp_fd;
	compat_uint_t time_out;
	compat_uint_t retry_count;
	compat_ulong_t uid;
	compat_ulong_t gid;
	compat_ulong_t file_mode;
	compat_ulong_t dir_mode;
};

static void *do_ncp_super_data_conv(void *raw_data)
{
	int version = *(unsigned int *)raw_data;

	if (version == 3) {
		struct compat_ncp_mount_data *c_n = raw_data;
		struct ncp_mount_data *n = raw_data;

		n->dir_mode = c_n->dir_mode;
		n->file_mode = c_n->file_mode;
		n->gid = c_n->gid;
		n->uid = c_n->uid;
		memmove (n->mounted_vol, c_n->mounted_vol, (sizeof (c_n->mounted_vol) + 3 * sizeof (unsigned int)));
		n->wdog_pid = c_n->wdog_pid;
		n->mounted_uid = c_n->mounted_uid;
	} else if (version == 4) {
		struct compat_ncp_mount_data_v4 *c_n = raw_data;
		struct ncp_mount_data_v4 *n = raw_data;

		n->dir_mode = c_n->dir_mode;
		n->file_mode = c_n->file_mode;
		n->gid = c_n->gid;
		n->uid = c_n->uid;
		n->retry_count = c_n->retry_count;
		n->time_out = c_n->time_out;
		n->ncp_fd = c_n->ncp_fd;
		n->wdog_pid = c_n->wdog_pid;
		n->mounted_uid = c_n->mounted_uid;
		n->flags = c_n->flags;
	} else if (version != 5) {
		return NULL;
	}

	return raw_data;
}

struct compat_smb_mount_data {
	compat_int_t version;
	__compat_uid_t mounted_uid;
	__compat_uid_t uid;
	__compat_gid_t gid;
	compat_mode_t file_mode;
	compat_mode_t dir_mode;
};

static void *do_smb_super_data_conv(void *raw_data)
{
	struct smb_mount_data *s = raw_data;
	struct compat_smb_mount_data *c_s = raw_data;

	if (c_s->version != SMB_MOUNT_OLDVERSION)
		goto out;
	s->dir_mode = c_s->dir_mode;
	s->file_mode = c_s->file_mode;
	s->gid = c_s->gid;
	s->uid = c_s->uid;
	s->mounted_uid = c_s->mounted_uid;
 out:
	return raw_data;
}

struct compat_nfs_string {
	compat_uint_t len;
	compat_uptr_t data;
};

static inline void compat_nfs_string(struct nfs_string *dst,
				     struct compat_nfs_string *src)
{
	dst->data = compat_ptr(src->data);
	dst->len = src->len;
}

struct compat_nfs4_mount_data_v1 {
	compat_int_t version;
	compat_int_t flags;
	compat_int_t rsize;
	compat_int_t wsize;
	compat_int_t timeo;
	compat_int_t retrans;
	compat_int_t acregmin;
	compat_int_t acregmax;
	compat_int_t acdirmin;
	compat_int_t acdirmax;
	struct compat_nfs_string client_addr;
	struct compat_nfs_string mnt_path;
	struct compat_nfs_string hostname;
	compat_uint_t host_addrlen;
	compat_uptr_t host_addr;
	compat_int_t proto;
	compat_int_t auth_flavourlen;
	compat_uptr_t auth_flavours;
};

static int do_nfs4_super_data_conv(void *raw_data)
{
	int version = *(compat_uint_t *) raw_data;

	if (version == 1) {
		struct compat_nfs4_mount_data_v1 *raw = raw_data;
		struct nfs4_mount_data *real = raw_data;

		/* copy the fields backwards */
		real->auth_flavours = compat_ptr(raw->auth_flavours);
		real->auth_flavourlen = raw->auth_flavourlen;
		real->proto = raw->proto;
		real->host_addr = compat_ptr(raw->host_addr);
		real->host_addrlen = raw->host_addrlen;
		compat_nfs_string(&real->hostname, &raw->hostname);
		compat_nfs_string(&real->mnt_path, &raw->mnt_path);
		compat_nfs_string(&real->client_addr, &raw->client_addr);
		real->acdirmax = raw->acdirmax;
		real->acdirmin = raw->acdirmin;
		real->acregmax = raw->acregmax;
		real->acregmin = raw->acregmin;
		real->retrans = raw->retrans;
		real->timeo = raw->timeo;
		real->wsize = raw->wsize;
		real->rsize = raw->rsize;
		real->flags = raw->flags;
		real->version = raw->version;
	}

	return 0;
}

#define SMBFS_NAME      "smbfs"
#define NCPFS_NAME      "ncpfs"
#define NFS4_NAME	"nfs4"

asmlinkage long compat_sys_mount(char __user * dev_name, char __user * dir_name,
				 char __user * type, unsigned long flags,
				 void __user * data)
{
	unsigned long type_page;
	unsigned long data_page;
	unsigned long dev_page;
	char *dir_page;
	int retval;

	retval = copy_mount_options (type, &type_page);
	if (retval < 0)
		goto out;

	dir_page = getname(dir_name);
	retval = PTR_ERR(dir_page);
	if (IS_ERR(dir_page))
		goto out1;

	retval = copy_mount_options (dev_name, &dev_page);
	if (retval < 0)
		goto out2;

	retval = copy_mount_options (data, &data_page);
	if (retval < 0)
		goto out3;

	retval = -EINVAL;

	if (type_page && data_page) {
		if (!strcmp((char *)type_page, SMBFS_NAME)) {
			do_smb_super_data_conv((void *)data_page);
		} else if (!strcmp((char *)type_page, NCPFS_NAME)) {
			do_ncp_super_data_conv((void *)data_page);
		} else if (!strcmp((char *)type_page, NFS4_NAME)) {
			if (do_nfs4_super_data_conv((void *) data_page))
				goto out4;
		}
	}

	lock_kernel();
	retval = do_mount((char*)dev_page, dir_page, (char*)type_page,
			flags, (void*)data_page);
	unlock_kernel();

 out4:
	free_page(data_page);
 out3:
	free_page(dev_page);
 out2:
	putname(dir_page);
 out1:
	free_page(type_page);
 out:
	return retval;
}

#define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de)))

struct compat_old_linux_dirent {
	compat_ulong_t	d_ino;
	compat_ulong_t	d_offset;
	unsigned short	d_namlen;
	char		d_name[1];
};

struct compat_readdir_callback {
	struct compat_old_linux_dirent __user *dirent;
	int result;
};

static int compat_fillonedir(void *__buf, const char *name, int namlen,
			loff_t offset, u64 ino, unsigned int d_type)
{
	struct compat_readdir_callback *buf = __buf;
	struct compat_old_linux_dirent __user *dirent;
	compat_ulong_t d_ino;

	if (buf->result)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->result = -EOVERFLOW;
		return -EOVERFLOW;
	}
	buf->result++;
	dirent = buf->dirent;
	if (!access_ok(VERIFY_WRITE, dirent,
			(unsigned long)(dirent->d_name + namlen + 1) -
				(unsigned long)dirent))
		goto efault;
	if (	__put_user(d_ino, &dirent->d_ino) ||
		__put_user(offset, &dirent->d_offset) ||
		__put_user(namlen, &dirent->d_namlen) ||
		__copy_to_user(dirent->d_name, name, namlen) ||
		__put_user(0, dirent->d_name + namlen))
		goto efault;
	return 0;
efault:
	buf->result = -EFAULT;
	return -EFAULT;
}

asmlinkage long compat_sys_old_readdir(unsigned int fd,
	struct compat_old_linux_dirent __user *dirent, unsigned int count)
{
	int error;
	struct file *file;
	struct compat_readdir_callback buf;

	error = -EBADF;
	file = fget(fd);
	if (!file)
		goto out;

	buf.result = 0;
	buf.dirent = dirent;

	error = vfs_readdir(file, compat_fillonedir, &buf);
	if (error >= 0)
		error = buf.result;

	fput(file);
out:
	return error;
}

struct compat_linux_dirent {
	compat_ulong_t	d_ino;
	compat_ulong_t	d_off;
	unsigned short	d_reclen;
	char		d_name[1];
};

struct compat_getdents_callback {
	struct compat_linux_dirent __user *current_dir;
	struct compat_linux_dirent __user *previous;
	int count;
	int error;
};

static int compat_filldir(void *__buf, const char *name, int namlen,
		loff_t offset, u64 ino, unsigned int d_type)
{
	struct compat_linux_dirent __user * dirent;
	struct compat_getdents_callback *buf = __buf;
	compat_ulong_t d_ino;
	int reclen = ALIGN(NAME_OFFSET(dirent) + namlen + 2, sizeof(compat_long_t));

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->error = -EOVERFLOW;
		return -EOVERFLOW;
	}
	dirent = buf->previous;
	if (dirent) {
		if (__put_user(offset, &dirent->d_off))
			goto efault;
	}
	dirent = buf->current_dir;
	if (__put_user(d_ino, &dirent->d_ino))
		goto efault;
	if (__put_user(reclen, &dirent->d_reclen))
		goto efault;
	if (copy_to_user(dirent->d_name, name, namlen))
		goto efault;
	if (__put_user(0, dirent->d_name + namlen))
		goto efault;
	if (__put_user(d_type, (char  __user *) dirent + reclen - 1))
		goto efault;
	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

asmlinkage long compat_sys_getdents(unsigned int fd,
		struct compat_linux_dirent __user *dirent, unsigned int count)
{
	struct file * file;
	struct compat_linux_dirent __user * lastdirent;
	struct compat_getdents_callback buf;
	int error;

	error = -EFAULT;
	if (!access_ok(VERIFY_WRITE, dirent, count))
		goto out;

	error = -EBADF;
	file = fget(fd);
	if (!file)
		goto out;

	buf.current_dir = dirent;
	buf.previous = NULL;
	buf.count = count;
	buf.error = 0;

	error = vfs_readdir(file, compat_filldir, &buf);
	if (error < 0)
		goto out_putf;
	error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		if (put_user(file->f_pos, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}

out_putf:
	fput(file);
out:
	return error;
}

#ifndef __ARCH_OMIT_COMPAT_SYS_GETDENTS64

struct compat_getdents_callback64 {
	struct linux_dirent64 __user *current_dir;
	struct linux_dirent64 __user *previous;
	int count;
	int error;
};

static int compat_filldir64(void * __buf, const char * name, int namlen, loff_t offset,
		     u64 ino, unsigned int d_type)
{
	struct linux_dirent64 __user *dirent;
	struct compat_getdents_callback64 *buf = __buf;
	int jj = NAME_OFFSET(dirent);
	int reclen = ALIGN(jj + namlen + 1, sizeof(u64));
	u64 off;

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	dirent = buf->previous;

	if (dirent) {
		if (__put_user_unaligned(offset, &dirent->d_off))
			goto efault;
	}
	dirent = buf->current_dir;
	if (__put_user_unaligned(ino, &dirent->d_ino))
		goto efault;
	off = 0;
	if (__put_user_unaligned(off, &dirent->d_off))
		goto efault;
	if (__put_user(reclen, &dirent->d_reclen))
		goto efault;
	if (__put_user(d_type, &dirent->d_type))
		goto efault;
	if (copy_to_user(dirent->d_name, name, namlen))
		goto efault;
	if (__put_user(0, dirent->d_name + namlen))
		goto efault;
	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

asmlinkage long compat_sys_getdents64(unsigned int fd,
		struct linux_dirent64 __user * dirent, unsigned int count)
{
	struct file * file;
	struct linux_dirent64 __user * lastdirent;
	struct compat_getdents_callback64 buf;
	int error;

	error = -EFAULT;
	if (!access_ok(VERIFY_WRITE, dirent, count))
		goto out;

	error = -EBADF;
	file = fget(fd);
	if (!file)
		goto out;

	buf.current_dir = dirent;
	buf.previous = NULL;
	buf.count = count;
	buf.error = 0;

	error = vfs_readdir(file, compat_filldir64, &buf);
	if (error < 0)
		goto out_putf;
	error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		typeof(lastdirent->d_off) d_off = file->f_pos;
		error = -EFAULT;
		if (__put_user_unaligned(d_off, &lastdirent->d_off))
			goto out_putf;
		error = count - buf.count;
	}

out_putf:
	fput(file);
out:
	return error;
}
#endif /* ! __ARCH_OMIT_COMPAT_SYS_GETDENTS64 */

static ssize_t compat_do_readv_writev(int type, struct file *file,
			       const struct compat_iovec __user *uvector,
			       unsigned long nr_segs, loff_t *pos)
{
	compat_ssize_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 (!access_ok(VERIFY_READ, 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;
	vector = iov;
	ret = -EINVAL;
	for (seg = 0 ; seg < nr_segs; seg++) {
		compat_ssize_t tmp = tot_len;
		compat_ssize_t len;
		compat_uptr_t buf;

		if (__get_user(len, &uvector->iov_len) ||
		    __get_user(buf, &uvector->iov_base)) {
			ret = -EFAULT;
			goto out;
		}
		if (len < 0)	/* size_t not fitting an compat_ssize_t .. */
			goto out;
		tot_len += len;
		if (tot_len < tmp) /* maths overflow on the compat_ssize_t */
			goto out;
		vector->iov_base = compat_ptr(buf);
		vector->iov_len = (compat_size_t) len;
		uvector++;
		vector++;
	}
	if (tot_len == 0) {
		ret = 0;
		goto out;
	}

	ret = rw_verify_area(type, file, pos, tot_len);
	if (ret < 0)
		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) {
		struct dentry *dentry = file->f_path.dentry;
		if (type == READ)
			fsnotify_access(dentry);
		else
			fsnotify_modify(dentry);
	}
	return ret;
}

asmlinkage ssize_t
compat_sys_readv(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen)
{
	struct file *file;
	ssize_t ret = -EBADF;

	file = fget(fd);
	if (!file)
		return -EBADF;

	if (!(file->f_mode & FMODE_READ))
		goto out;

	ret = -EINVAL;
	if (!file->f_op || (!file->f_op->aio_read && !file->f_op->read))
		goto out;

	ret = compat_do_readv_writev(READ, file, vec, vlen, &file->f_pos);

out:
	fput(file);
	return ret;
}

asmlinkage ssize_t
compat_sys_writev(unsigned long fd, const struct compat_iovec __user *vec, unsigned long vlen)
{
	struct file *file;
	ssize_t ret = -EBADF;

	file = fget(fd);
	if (!file)
		return -EBADF;
	if (!(file->f_mode & FMODE_WRITE))
		goto out;

	ret = -EINVAL;
	if (!file->f_op || (!file->f_op->aio_write && !file->f_op->write))
		goto out;

	ret = compat_do_readv_writev(WRITE, file, vec, vlen, &file->f_pos);

out:
	fput(file);
	return ret;
}

asmlinkage long
compat_sys_vmsplice(int fd, const struct compat_iovec __user *iov32,
		    unsigned int nr_segs, unsigned int flags)
{
	unsigned i;
	struct iovec __user *iov;
	if (nr_segs > UIO_MAXIOV)
		return -EINVAL;
	iov = compat_alloc_user_space(nr_segs * sizeof(struct iovec));
	for (i = 0; i < nr_segs; i++) {
		struct compat_iovec v;
		if (get_user(v.iov_base, &iov32[i].iov_base) ||
		    get_user(v.iov_len, &iov32[i].iov_len) ||
		    put_user(compat_ptr(v.iov_base), &iov[i].iov_base) ||
		    put_user(v.iov_len, &iov[i].iov_len))
			return -EFAULT;
	}
	return sys_vmsplice(fd, iov, nr_segs, flags);
}

/*
 * Exactly like fs/open.c:sys_open(), except that it doesn't set the
 * O_LARGEFILE flag.
 */
asmlinkage long
compat_sys_open(const char __user *filename, int flags, int mode)
{
	return do_sys_open(AT_FDCWD, filename, flags, mode);
}

/*
 * Exactly like fs/open.c:sys_openat(), except that it doesn't set the
 * O_LARGEFILE flag.
 */
asmlinkage long
compat_sys_openat(unsigned int dfd, const char __user *filename, int flags, int mode)
{
	return do_sys_open(dfd, filename, flags, mode);
}

/*
 * compat_count() counts the number of arguments/envelopes. It is basically
 * a copy of count() from fs/exec.c, except that it works with 32 bit argv
 * and envp pointers.
 */
static int compat_count(compat_uptr_t __user *argv, int max)
{
	int i = 0;

	if (argv != NULL) {
		for (;;) {
			compat_uptr_t p;

			if (get_user(p, argv))
				return -EFAULT;
			if (!p)
				break;
			argv++;
			if (i++ >= max)
				return -E2BIG;
		}
	}
	return i;
}

/*
 * compat_copy_strings() is basically a copy of copy_strings() from fs/exec.c
 * except that it works with 32 bit argv and envp pointers.
 */
static int compat_copy_strings(int argc, compat_uptr_t __user *argv,
				struct linux_binprm *bprm)
{
	struct page *kmapped_page = NULL;
	char *kaddr = NULL;
	unsigned long kpos = 0;
	int ret;

	while (argc-- > 0) {
		compat_uptr_t str;
		int len;
		unsigned long pos;

		if (get_user(str, argv+argc) ||
		    !(len = strnlen_user(compat_ptr(str), MAX_ARG_STRLEN))) {
			ret = -EFAULT;
			goto out;
		}

		if (len > MAX_ARG_STRLEN) {
			ret = -E2BIG;
			goto out;
		}

		/* We're going to work our way backwords. */
		pos = bprm->p;
		str += len;
		bprm->p -= len;

		while (len > 0) {
			int offset, bytes_to_copy;

			offset = pos % PAGE_SIZE;
			if (offset == 0)
				offset = PAGE_SIZE;

			bytes_to_copy = offset;
			if (bytes_to_copy > len)
				bytes_to_copy = len;

			offset -= bytes_to_copy;
			pos -= bytes_to_copy;
			str -= bytes_to_copy;
			len -= bytes_to_copy;

			if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
				struct page *page;

#ifdef CONFIG_STACK_GROWSUP
				ret = expand_stack_downwards(bprm->vma, pos);
				if (ret < 0) {
					/* We've exceed the stack rlimit. */
					ret = -E2BIG;
					goto out;
				}
#endif
				ret = get_user_pages(current, bprm->mm, pos,
						     1, 1, 1, &page, NULL);
				if (ret <= 0) {
					/* We've exceed the stack rlimit. */
					ret = -E2BIG;
					goto out;
				}

				if (kmapped_page) {
					flush_kernel_dcache_page(kmapped_page);
					kunmap(kmapped_page);
					put_page(kmapped_page);
				}
				kmapped_page = page;
				kaddr = kmap(kmapped_page);
				kpos = pos & PAGE_MASK;
				flush_cache_page(bprm->vma, kpos,
						 page_to_pfn(kmapped_page));
			}
			if (copy_from_user(kaddr+offset, compat_ptr(str),
						bytes_to_copy)) {
				ret = -EFAULT;
				goto out;
			}
		}
	}
	ret = 0;
out:
	if (kmapped_page) {
		flush_kernel_dcache_page(kmapped_page);
		kunmap(kmapped_page);
		put_page(kmapped_page);
	}
	return ret;
}

/*
 * compat_do_execve() is mostly a copy of do_execve(), with the exception
 * that it processes 32 bit argv and envp pointers.
 */
int compat_do_execve(char * filename,
	compat_uptr_t __user *argv,
	compat_uptr_t __user *envp,
	struct pt_regs * regs)
{
	struct linux_binprm *bprm;
	struct file *file;
	int retval;

	retval = -ENOMEM;
	bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
	if (!bprm)
		goto out_ret;

	file = open_exec(filename);
	retval = PTR_ERR(file);
	if (IS_ERR(file))
		goto out_kfree;

	sched_exec();

	bprm->file = file;
	bprm->filename = filename;
	bprm->interp = filename;

	retval = bprm_mm_init(bprm);
	if (retval)
		goto out_file;

	bprm->argc = compat_count(argv, MAX_ARG_STRINGS);
	if ((retval = bprm->argc) < 0)
		goto out_mm;

	bprm->envc = compat_count(envp, MAX_ARG_STRINGS);
	if ((retval = bprm->envc) < 0)
		goto out_mm;

	retval = security_bprm_alloc(bprm);
	if (retval)
		goto out;

	retval = prepare_binprm(bprm);
	if (retval < 0)
		goto out;

	retval = copy_strings_kernel(1, &bprm->filename, bprm);
	if (retval < 0)
		goto out;

	bprm->exec = bprm->p;
	retval = compat_copy_strings(bprm->envc, envp, bprm);
	if (retval < 0)
		goto out;

	retval = compat_copy_strings(bprm->argc, argv, bprm);
	if (retval < 0)
		goto out;

	retval = search_binary_handler(bprm, regs);
	if (retval >= 0) {
		/* execve success */
		security_bprm_free(bprm);
		acct_update_integrals(current);
		free_bprm(bprm);
		return retval;
	}

out:
	if (bprm->security)
		security_bprm_free(bprm);

out_mm:
	if (bprm->mm)
		mmput(bprm->mm);

out_file:
	if (bprm->file) {
		allow_write_access(bprm->file);
		fput(bprm->file);
	}

out_kfree:
	free_bprm(bprm);

out_ret:
	return retval;
}

#define __COMPAT_NFDBITS       (8 * sizeof(compat_ulong_t))

/*
 * Ooo, nasty.  We need here to frob 32-bit unsigned longs to
 * 64-bit unsigned longs.
 */
static
int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
			unsigned long *fdset)
{
	nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS);
	if (ufdset) {
		unsigned long odd;

		if (!access_ok(VERIFY_WRITE, ufdset, nr*sizeof(compat_ulong_t)))
			return -EFAULT;

		odd = nr & 1UL;
		nr &= ~1UL;
		while (nr) {
			unsigned long h, l;
			if (__get_user(l, ufdset) || __get_user(h, ufdset+1))
				return -EFAULT;
			ufdset += 2;
			*fdset++ = h << 32 | l;
			nr -= 2;
		}
		if (odd && __get_user(*fdset, ufdset))
			return -EFAULT;
	} else {
		/* Tricky, must clear full unsigned long in the
		 * kernel fdset at the end, this makes sure that
		 * actually happens.
		 */
		memset(fdset, 0, ((nr + 1) & ~1)*sizeof(compat_ulong_t));
	}
	return 0;
}

static
int compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
		      unsigned long *fdset)
{
	unsigned long odd;
	nr = DIV_ROUND_UP(nr, __COMPAT_NFDBITS);

	if (!ufdset)
		return 0;

	odd = nr & 1UL;
	nr &= ~1UL;
	while (nr) {
		unsigned long h, l;
		l = *fdset++;
		h = l >> 32;
		if (__put_user(l, ufdset) || __put_user(h, ufdset+1))
			return -EFAULT;
		ufdset += 2;
		nr -= 2;
	}
	if (odd && __put_user(*fdset, ufdset))
		return -EFAULT;
	return 0;
}


/*
 * This is a virtual copy of sys_select from fs/select.c and probably
 * should be compared to it from time to time
 */

/*
 * We can actually return ERESTARTSYS instead of EINTR, but I'd
 * like to be certain this leads to no problems. So I return
 * EINTR just for safety.
 *
 * Update: ERESTARTSYS breaks at least the xview clock binary, so
 * I'm trying ERESTARTNOHAND which restart only when you want to.
 */
#define MAX_SELECT_SECONDS \
	((unsigned long) (MAX_SCHEDULE_TIMEOUT / HZ)-1)

int compat_core_sys_select(int n, compat_ulong_t __user *inp,
	compat_ulong_t __user *outp, compat_ulong_t __user *exp, s64 *timeout)
{
	fd_set_bits fds;
	void *bits;
	int size, max_fds, ret = -EINVAL;
	struct fdtable *fdt;
	long stack_fds[SELECT_STACK_ALLOC/sizeof(long)];

	if (n < 0)
		goto out_nofds;

	/* max_fds can increase, so grab it once to avoid race */
	rcu_read_lock();
	fdt = files_fdtable(current->files);
	max_fds = fdt->max_fds;
	rcu_read_unlock();
	if (n > max_fds)
		n = max_fds;

	/*
	 * We need 6 bitmaps (in/out/ex for both incoming and outgoing),
	 * since we used fdset we need to allocate memory in units of
	 * long-words.
	 */
	size = FDS_BYTES(n);
	bits = stack_fds;
	if (size > sizeof(stack_fds) / 6) {
		bits = kmalloc(6 * size, GFP_KERNEL);
		ret = -ENOMEM;
		if (!bits)
			goto out_nofds;
	}
	fds.in      = (unsigned long *)  bits;
	fds.out     = (unsigned long *) (bits +   size);
	fds.ex      = (unsigned long *) (bits + 2*size);
	fds.res_in  = (unsigned long *) (bits + 3*size);
	fds.res_out = (unsigned long *) (bits + 4*size);
	fds.res_ex  = (unsigned long *) (bits + 5*size);

	if ((ret = compat_get_fd_set(n, inp, fds.in)) ||
	    (ret = compat_get_fd_set(n, outp, fds.out)) ||
	    (ret = compat_get_fd_set(n, exp, fds.ex)))
		goto out;
	zero_fd_set(n, fds.res_in);
	zero_fd_set(n, fds.res_out);
	zero_fd_set(n, fds.res_ex);

	ret = do_select(n, &fds, timeout);

	if (ret < 0)
		goto out;
	if (!ret) {
		ret = -ERESTARTNOHAND;
		if (signal_pending(current))
			goto out;
		ret = 0;
	}

	if (compat_set_fd_set(n, inp, fds.res_in) ||
	    compat_set_fd_set(n, outp, fds.res_out) ||
	    compat_set_fd_set(n, exp, fds.res_ex))
		ret = -EFAULT;
out:
	if (bits != stack_fds)
		kfree(bits);
out_nofds:
	return ret;
}

asmlinkage long compat_sys_select(int n, compat_ulong_t __user *inp,
	compat_ulong_t __user *outp, compat_ulong_t __user *exp,
	struct compat_timeval __user *tvp)
{
	s64 timeout = -1;
	struct compat_timeval tv;
	int ret;

	if (tvp) {
		if (copy_from_user(&tv, tvp, sizeof(tv)))
			return -EFAULT;

		if (tv.tv_sec < 0 || tv.tv_usec < 0)
			return -EINVAL;

		/* Cast to u64 to make GCC stop complaining */
		if ((u64)tv.tv_sec >= (u64)MAX_INT64_SECONDS)
			timeout = -1;	/* infinite */
		else {
			timeout = DIV_ROUND_UP(tv.tv_usec, 1000000/HZ);
			timeout += tv.tv_sec * HZ;
		}
	}

	ret = compat_core_sys_select(n, inp, outp, exp, &timeout);

	if (tvp) {
		struct compat_timeval rtv;

		if (current->personality & STICKY_TIMEOUTS)
			goto sticky;
		rtv.tv_usec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ));
		rtv.tv_sec = timeout;
		if (compat_timeval_compare(&rtv, &tv) >= 0)
			rtv = tv;
		if (copy_to_user(tvp, &rtv, sizeof(rtv))) {
sticky:
			/*
			 * If an application puts its timeval in read-only
			 * memory, we don't want the Linux-specific update to
			 * the timeval to cause a fault after the select has
			 * completed successfully. However, because we're not
			 * updating the timeval, we can't restart the system
			 * call.
			 */
			if (ret == -ERESTARTNOHAND)
				ret = -EINTR;
		}
	}

	return ret;
}

#ifdef HAVE_SET_RESTORE_SIGMASK
asmlinkage long compat_sys_pselect7(int n, compat_ulong_t __user *inp,
	compat_ulong_t __user *outp, compat_ulong_t __user *exp,
	struct compat_timespec __user *tsp, compat_sigset_t __user *sigmask,
	compat_size_t sigsetsize)
{
	compat_sigset_t ss32;
	sigset_t ksigmask, sigsaved;
	s64 timeout = MAX_SCHEDULE_TIMEOUT;
	struct compat_timespec ts;
	int ret;

	if (tsp) {
		if (copy_from_user(&ts, tsp, sizeof(ts)))
			return -EFAULT;

		if (ts.tv_sec < 0 || ts.tv_nsec < 0)
			return -EINVAL;
	}

	if (sigmask) {
		if (sigsetsize != sizeof(compat_sigset_t))
			return -EINVAL;
		if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
			return -EFAULT;
		sigset_from_compat(&ksigmask, &ss32);

		sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
		sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
	}

	do {
		if (tsp) {
			if ((unsigned long)ts.tv_sec < MAX_SELECT_SECONDS) {
				timeout = DIV_ROUND_UP(ts.tv_nsec, 1000000000/HZ);
				timeout += ts.tv_sec * (unsigned long)HZ;
				ts.tv_sec = 0;
				ts.tv_nsec = 0;
			} else {
				ts.tv_sec -= MAX_SELECT_SECONDS;
				timeout = MAX_SELECT_SECONDS * HZ;
			}
		}

		ret = compat_core_sys_select(n, inp, outp, exp, &timeout);

	} while (!ret && !timeout && tsp && (ts.tv_sec || ts.tv_nsec));

	if (tsp) {
		struct compat_timespec rts;

		if (current->personality & STICKY_TIMEOUTS)
			goto sticky;

		rts.tv_sec = timeout / HZ;
		rts.tv_nsec = (timeout % HZ) * (NSEC_PER_SEC/HZ);
		if (rts.tv_nsec >= NSEC_PER_SEC) {
			rts.tv_sec++;
			rts.tv_nsec -= NSEC_PER_SEC;
		}
		if (compat_timespec_compare(&rts, &ts) >= 0)
			rts = ts;
		if (copy_to_user(tsp, &rts, sizeof(rts))) {
sticky:
			/*
			 * If an application puts its timeval in read-only
			 * memory, we don't want the Linux-specific update to
			 * the timeval to cause a fault after the select has
			 * completed successfully. However, because we're not
			 * updating the timeval, we can't restart the system
			 * call.
			 */
			if (ret == -ERESTARTNOHAND)
				ret = -EINTR;
		}
	}

	if (ret == -ERESTARTNOHAND) {
		/*
		 * Don't restore the signal mask yet. Let do_signal() deliver
		 * the signal on the way back to userspace, before the signal
		 * mask is restored.
		 */
		if (sigmask) {
			memcpy(&current->saved_sigmask, &sigsaved,
					sizeof(sigsaved));
			set_restore_sigmask();
		}
	} else if (sigmask)
		sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	return ret;
}

asmlinkage long compat_sys_pselect6(int n, compat_ulong_t __user *inp,
	compat_ulong_t __user *outp, compat_ulong_t __user *exp,
	struct compat_timespec __user *tsp, void __user *sig)
{
	compat_size_t sigsetsize = 0;
	compat_uptr_t up = 0;

	if (sig) {
		if (!access_ok(VERIFY_READ, sig,
				sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
		    	__get_user(up, (compat_uptr_t __user *)sig) ||
		    	__get_user(sigsetsize,
				(compat_size_t __user *)(sig+sizeof(up))))
			return -EFAULT;
	}
	return compat_sys_pselect7(n, inp, outp, exp, tsp, compat_ptr(up),
					sigsetsize);
}

asmlinkage long compat_sys_ppoll(struct pollfd __user *ufds,
	unsigned int nfds, struct compat_timespec __user *tsp,
	const compat_sigset_t __user *sigmask, compat_size_t sigsetsize)
{
	compat_sigset_t ss32;
	sigset_t ksigmask, sigsaved;
	struct compat_timespec ts;
	s64 timeout = -1;
	int ret;

	if (tsp) {
		if (copy_from_user(&ts, tsp, sizeof(ts)))
			return -EFAULT;

		/* We assume that ts.tv_sec is always lower than
		   the number of seconds that can be expressed in
		   an s64. Otherwise the compiler bitches at us */
		timeout = DIV_ROUND_UP(ts.tv_nsec, 1000000000/HZ);
		timeout += ts.tv_sec * HZ;
	}

	if (sigmask) {
		if (sigsetsize != sizeof(compat_sigset_t))
			return -EINVAL;
		if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
			return -EFAULT;
		sigset_from_compat(&ksigmask, &ss32);

		sigdelsetmask(&ksigmask, sigmask(SIGKILL)|sigmask(SIGSTOP));
		sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
	}

	ret = do_sys_poll(ufds, nfds, &timeout);

	/* We can restart this syscall, usually */
	if (ret == -EINTR) {
		/*
		 * Don't restore the signal mask yet. Let do_signal() deliver
		 * the signal on the way back to userspace, before the signal
		 * mask is restored.
		 */
		if (sigmask) {
			memcpy(&current->saved_sigmask, &sigsaved,
				sizeof(sigsaved));
			set_restore_sigmask();
		}
		ret = -ERESTARTNOHAND;
	} else if (sigmask)
		sigprocmask(SIG_SETMASK, &sigsaved, NULL);

	if (tsp && timeout >= 0) {
		struct compat_timespec rts;

		if (current->personality & STICKY_TIMEOUTS)
			goto sticky;
		/* Yes, we know it's actually an s64, but it's also positive. */
		rts.tv_nsec = jiffies_to_usecs(do_div((*(u64*)&timeout), HZ)) *
					1000;
		rts.tv_sec = timeout;
		if (compat_timespec_compare(&rts, &ts) >= 0)
			rts = ts;
		if (copy_to_user(tsp, &rts, sizeof(rts))) {
sticky:
			/*
			 * If an application puts its timeval in read-only
			 * memory, we don't want the Linux-specific update to
			 * the timeval to cause a fault after the select has
			 * completed successfully. However, because we're not
			 * updating the timeval, we can't restart the system
			 * call.
			 */
			if (ret == -ERESTARTNOHAND && timeout >= 0)
				ret = -EINTR;
		}
	}

	return ret;
}
#endif /* HAVE_SET_RESTORE_SIGMASK */

#if defined(CONFIG_NFSD) || defined(CONFIG_NFSD_MODULE)
/* Stuff for NFS server syscalls... */
struct compat_nfsctl_svc {
	u16			svc32_port;
	s32			svc32_nthreads;
};

struct compat_nfsctl_client {
	s8			cl32_ident[NFSCLNT_IDMAX+1];
	s32			cl32_naddr;
	struct in_addr		cl32_addrlist[NFSCLNT_ADDRMAX];
	s32			cl32_fhkeytype;
	s32			cl32_fhkeylen;
	u8			cl32_fhkey[NFSCLNT_KEYMAX];
};

struct compat_nfsctl_export {
	char		ex32_client[NFSCLNT_IDMAX+1];
	char		ex32_path[NFS_MAXPATHLEN+1];
	compat_dev_t	ex32_dev;
	compat_ino_t	ex32_ino;
	compat_int_t	ex32_flags;
	__compat_uid_t	ex32_anon_uid;
	__compat_gid_t	ex32_anon_gid;
};

struct compat_nfsctl_fdparm {
	struct sockaddr		gd32_addr;
	s8			gd32_path[NFS_MAXPATHLEN+1];
	compat_int_t		gd32_version;
};

struct compat_nfsctl_fsparm {
	struct sockaddr		gd32_addr;
	s8			gd32_path[NFS_MAXPATHLEN+1];
	compat_int_t		gd32_maxlen;
};

struct compat_nfsctl_arg {
	compat_int_t		ca32_version;	/* safeguard */
	union {
		struct compat_nfsctl_svc	u32_svc;
		struct compat_nfsctl_client	u32_client;
		struct compat_nfsctl_export	u32_export;
		struct compat_nfsctl_fdparm	u32_getfd;
		struct compat_nfsctl_fsparm	u32_getfs;
	} u;
#define ca32_svc	u.u32_svc
#define ca32_client	u.u32_client
#define ca32_export	u.u32_export
#define ca32_getfd	u.u32_getfd
#define ca32_getfs	u.u32_getfs
};

union compat_nfsctl_res {
	__u8			cr32_getfh[NFS_FHSIZE];
	struct knfsd_fh		cr32_getfs;
};

static int compat_nfs_svc_trans(struct nfsctl_arg *karg,
				struct compat_nfsctl_arg __user *arg)
{
	if (!access_ok(VERIFY_READ, &arg->ca32_svc, sizeof(arg->ca32_svc)) ||
		get_user(karg->ca_version, &arg->ca32_version) ||
		__get_user(karg->ca_svc.svc_port, &arg->ca32_svc.svc32_port) ||
		__get_user(karg->ca_svc.svc_nthreads,
				&arg->ca32_svc.svc32_nthreads))
		return -EFAULT;
	return 0;
}

static int compat_nfs_clnt_trans(struct nfsctl_arg *karg,
				struct compat_nfsctl_arg __user *arg)
{
	if (!access_ok(VERIFY_READ, &arg->ca32_client,
			sizeof(arg->ca32_client)) ||
		get_user(karg->ca_version, &arg->ca32_version) ||
		__copy_from_user(&karg->ca_client.cl_ident[0],
				&arg->ca32_client.cl32_ident[0],
				NFSCLNT_IDMAX) ||
		__get_user(karg->ca_client.cl_naddr,
				&arg->ca32_client.cl32_naddr) ||
		__copy_from_user(&karg->ca_client.cl_addrlist[0],
				&arg->ca32_client.cl32_addrlist[0],
				(sizeof(struct in_addr) * NFSCLNT_ADDRMAX)) ||
		__get_user(karg->ca_client.cl_fhkeytype,
				&arg->ca32_client.cl32_fhkeytype) ||
		__get_user(karg->ca_client.cl_fhkeylen,
				&arg->ca32_client.cl32_fhkeylen) ||
		__copy_from_user(&karg->ca_client.cl_fhkey[0],
				&arg->ca32_client.cl32_fhkey[0],
				NFSCLNT_KEYMAX))
		return -EFAULT;

	return 0;
}

static int compat_nfs_exp_trans(struct nfsctl_arg *karg,
				struct compat_nfsctl_arg __user *arg)
{
	if (!access_ok(VERIFY_READ, &arg->ca32_export,
				sizeof(arg->ca32_export)) ||
		get_user(karg->ca_version, &arg->ca32_version) ||
		__copy_from_user(&karg->ca_export.ex_client[0],
				&arg->ca32_export.ex32_client[0],
				NFSCLNT_IDMAX) ||
		__copy_from_user(&karg->ca_export.ex_path[0],
				&arg->ca32_export.ex32_path[0],
				NFS_MAXPATHLEN) ||
		__get_user(karg->ca_export.ex_dev,
				&arg->ca32_export.ex32_dev) ||
		__get_user(karg->ca_export.ex_ino,
				&arg->ca32_export.ex32_ino) ||
		__get_user(karg->ca_export.ex_flags,
				&arg->ca32_export.ex32_flags) ||
		__get_user(karg->ca_export.ex_anon_uid,
				&arg->ca32_export.ex32_anon_uid) ||
		__get_user(karg->ca_export.ex_anon_gid,
				&arg->ca32_export.ex32_anon_gid))
		return -EFAULT;
	SET_UID(karg->ca_export.ex_anon_uid, karg->ca_export.ex_anon_uid);
	SET_GID(karg->ca_export.ex_anon_gid, karg->ca_export.ex_anon_gid);

	return 0;
}

static int compat_nfs_getfd_trans(struct nfsctl_arg *karg,
				struct compat_nfsctl_arg __user *arg)
{
	if (!access_ok(VERIFY_READ, &arg->ca32_getfd,
			sizeof(arg->ca32_getfd)) ||
		get_user(karg->ca_version, &arg->ca32_version) ||
		__copy_from_user(&karg->ca_getfd.gd_addr,
				&arg->ca32_getfd.gd32_addr,
				(sizeof(struct sockaddr))) ||
		__copy_from_user(&karg->ca_getfd.gd_path,
				&arg->ca32_getfd.gd32_path,
				(NFS_MAXPATHLEN+1)) ||
		__get_user(karg->ca_getfd.gd_version,
				&arg->ca32_getfd.gd32_version))
		return -EFAULT;

	return 0;
}

static int compat_nfs_getfs_trans(struct nfsctl_arg *karg,
				struct compat_nfsctl_arg __user *arg)
{
	if (!access_ok(VERIFY_READ,&arg->ca32_getfs,sizeof(arg->ca32_getfs)) ||
		get_user(karg->ca_version, &arg->ca32_version) ||
		__copy_from_user(&karg->ca_getfs.gd_addr,
				&arg->ca32_getfs.gd32_addr,
				(sizeof(struct sockaddr))) ||
		__copy_from_user(&karg->ca_getfs.gd_path,
				&arg->ca32_getfs.gd32_path,
				(NFS_MAXPATHLEN+1)) ||
		__get_user(karg->ca_getfs.gd_maxlen,
				&arg->ca32_getfs.gd32_maxlen))
		return -EFAULT;

	return 0;
}

/* This really doesn't need translations, we are only passing
 * back a union which contains opaque nfs file handle data.
 */
static int compat_nfs_getfh_res_trans(union nfsctl_res *kres,
				union compat_nfsctl_res __user *res)
{
	int err;

	err = copy_to_user(res, kres, sizeof(*res));

	return (err) ? -EFAULT : 0;
}

asmlinkage long compat_sys_nfsservctl(int cmd,
				struct compat_nfsctl_arg __user *arg,
				union compat_nfsctl_res __user *res)
{
	struct nfsctl_arg *karg;
	union nfsctl_res *kres;
	mm_segment_t oldfs;
	int err;

	karg = kmalloc(sizeof(*karg), GFP_USER);
	kres = kmalloc(sizeof(*kres), GFP_USER);
	if(!karg || !kres) {
		err = -ENOMEM;
		goto done;
	}

	switch(cmd) {
	case NFSCTL_SVC:
		err = compat_nfs_svc_trans(karg, arg);
		break;

	case NFSCTL_ADDCLIENT:
		err = compat_nfs_clnt_trans(karg, arg);
		break;

	case NFSCTL_DELCLIENT:
		err = compat_nfs_clnt_trans(karg, arg);
		break;

	case NFSCTL_EXPORT:
	case NFSCTL_UNEXPORT:
		err = compat_nfs_exp_trans(karg, arg);
		break;

	case NFSCTL_GETFD:
		err = compat_nfs_getfd_trans(karg, arg);
		break;

	case NFSCTL_GETFS:
		err = compat_nfs_getfs_trans(karg, arg);
		break;

	default:
		err = -EINVAL;
		break;
	}

	if (err)
		goto done;

	oldfs = get_fs();
	set_fs(KERNEL_DS);
	/* The __user pointer casts are valid because of the set_fs() */
	err = sys_nfsservctl(cmd, (void __user *) karg, (void __user *) kres);
	set_fs(oldfs);

	if (err)
		goto done;

	if((cmd == NFSCTL_GETFD) ||
	   (cmd == NFSCTL_GETFS))
		err = compat_nfs_getfh_res_trans(kres, res);

done:
	kfree(karg);
	kfree(kres);
	return err;
}
#else /* !NFSD */
long asmlinkage compat_sys_nfsservctl(int cmd, void *notused, void *notused2)
{
	return sys_ni_syscall();
}
#endif

#ifdef CONFIG_EPOLL

#ifdef HAVE_SET_RESTORE_SIGMASK
asmlinkage long compat_sys_epoll_pwait(int epfd,
			struct compat_epoll_event __user *events,
			int maxevents, int timeout,
			const compat_sigset_t __user *sigmask,
			compat_size_t sigsetsize)
{
	long err;
	compat_sigset_t csigmask;
	sigset_t ksigmask, sigsaved;

	/*
	 * If the caller wants a certain signal mask to be set during the wait,
	 * we apply it here.
	 */
	if (sigmask) {
		if (sigsetsize != sizeof(compat_sigset_t))
			return -EINVAL;
		if (copy_from_user(&csigmask, sigmask, sizeof(csigmask)))
			return -EFAULT;
		sigset_from_compat(&ksigmask, &csigmask);
		sigdelsetmask(&ksigmask, sigmask(SIGKILL) | sigmask(SIGSTOP));
		sigprocmask(SIG_SETMASK, &ksigmask, &sigsaved);
	}

	err = sys_epoll_wait(epfd, events, maxevents, timeout);

	/*
	 * If we changed the signal mask, we need to restore the original one.
	 * In case we've got a signal while waiting, we do not restore the
	 * signal mask yet, and we allow do_signal() to deliver the signal on
	 * the way back to userspace, before the signal mask is restored.
	 */
	if (sigmask) {
		if (err == -EINTR) {
			memcpy(&current->saved_sigmask, &sigsaved,
			       sizeof(sigsaved));
			set_restore_sigmask();
		} else
			sigprocmask(SIG_SETMASK, &sigsaved, NULL);
	}

	return err;
}
#endif /* HAVE_SET_RESTORE_SIGMASK */

#endif /* CONFIG_EPOLL */

#ifdef CONFIG_SIGNALFD

asmlinkage long compat_sys_signalfd4(int ufd,
				     const compat_sigset_t __user *sigmask,
				     compat_size_t sigsetsize, int flags)
{
	compat_sigset_t ss32;
	sigset_t tmp;
	sigset_t __user *ksigmask;

	if (sigsetsize != sizeof(compat_sigset_t))
		return -EINVAL;
	if (copy_from_user(&ss32, sigmask, sizeof(ss32)))
		return -EFAULT;
	sigset_from_compat(&tmp, &ss32);
	ksigmask = compat_alloc_user_space(sizeof(sigset_t));
	if (copy_to_user(ksigmask, &tmp, sizeof(sigset_t)))
		return -EFAULT;

	return sys_signalfd4(ufd, ksigmask, sizeof(sigset_t), flags);
}

asmlinkage long compat_sys_signalfd(int ufd,
				    const compat_sigset_t __user *sigmask,
				    compat_size_t sigsetsize)
{
	return compat_sys_signalfd4(ufd, sigmask, sigsetsize, 0);
}
#endif /* CONFIG_SIGNALFD */

#ifdef CONFIG_TIMERFD

asmlinkage long compat_sys_timerfd_settime(int ufd, int flags,
				   const struct compat_itimerspec __user *utmr,
				   struct compat_itimerspec __user *otmr)
{
	int error;
	struct itimerspec t;
	struct itimerspec __user *ut;

	if (get_compat_itimerspec(&t, utmr))
		return -EFAULT;
	ut = compat_alloc_user_space(2 * sizeof(struct itimerspec));
	if (copy_to_user(&ut[0], &t, sizeof(t)))
		return -EFAULT;
	error = sys_timerfd_settime(ufd, flags, &ut[0], &ut[1]);
	if (!error && otmr)
		error = (copy_from_user(&t, &ut[1], sizeof(struct itimerspec)) ||
			 put_compat_itimerspec(otmr, &t)) ? -EFAULT: 0;

	return error;
}

asmlinkage long compat_sys_timerfd_gettime(int ufd,
				   struct compat_itimerspec __user *otmr)
{
	int error;
	struct itimerspec t;
	struct itimerspec __user *ut;

	ut = compat_alloc_user_space(sizeof(struct itimerspec));
	error = sys_timerfd_gettime(ufd, ut);
	if (!error)
		error = (copy_from_user(&t, ut, sizeof(struct itimerspec)) ||
			 put_compat_itimerspec(otmr, &t)) ? -EFAULT: 0;

	return error;
}

#endif /* CONFIG_TIMERFD */