[PATCH] Linux 2.6.x VM86 interrupt emulation fixes

[linux-2.6] / 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
 *  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/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 <linux/ioctl32.h>
#include <linux/ioctl.h>
#include <linux/init.h>
#include <linux/sockios.h>      /* for SIOCDEVPRIVATE */
#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/dnotify.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 <net/sock.h>           /* siocdevprivate_ioctl */

#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/ioctls.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 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_utimes(char __user *filename, struct compat_timeval __user *t)
{
        struct timeval tv[2];

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

asmlinkage long compat_sys_newstat(char __user * filename,
                struct compat_stat __user *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 __user * filename,
                struct compat_stat __user *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 __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) &
                    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 *path, struct compat_statfs __user *buf)
{
        struct nameidata nd;
        int error;

        error = user_path_walk(path, &nd);
        if (!error) {
                struct kstatfs 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 __user *buf)
{
        struct file * file;
        struct kstatfs 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;
}

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) &
                    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 *path, compat_size_t sz, struct compat_statfs64 __user *buf)
{
        struct nameidata nd;
        int error;

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

        error = user_path_walk(path, &nd);
        if (!error) {
                struct kstatfs tmp;
                error = vfs_statfs(nd.dentry->d_inode->i_sb, &tmp);
                if (!error && put_compat_statfs64(buf, &tmp))
                        error = -EFAULT;
                path_release(&nd);
        }
        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_dentry->d_inode->i_sb, &tmp);
        if (!error && put_compat_statfs64(buf, &tmp))
                error = -EFAULT;
        fput(file);
out:
        return error;
}

/* ioctl32 stuff, used by sparc64, parisc, s390x, ppc64, x86_64, MIPS */

#define IOCTL_HASHSIZE 256
static struct ioctl_trans *ioctl32_hash_table[IOCTL_HASHSIZE];
static DECLARE_RWSEM(ioctl32_sem);

extern struct ioctl_trans ioctl_start[];
extern int ioctl_table_size;

static inline unsigned long ioctl32_hash(unsigned long cmd)
{
        return (((cmd >> 6) ^ (cmd >> 4) ^ cmd)) % IOCTL_HASHSIZE;
}

static void ioctl32_insert_translation(struct ioctl_trans *trans)
{
        unsigned long hash;
        struct ioctl_trans *t;

        hash = ioctl32_hash (trans->cmd);
        if (!ioctl32_hash_table[hash])
                ioctl32_hash_table[hash] = trans;
        else {
                t = ioctl32_hash_table[hash];
                while (t->next)
                        t = t->next;
                trans->next = NULL;
                t->next = trans;
        }
}

static int __init init_sys32_ioctl(void)
{
        int i;

        for (i = 0; i < ioctl_table_size; i++) {
                if (ioctl_start[i].next != 0) { 
                        printk("ioctl translation %d bad\n",i); 
                        return -1;
                }

                ioctl32_insert_translation(&ioctl_start[i]);
        }
        return 0;
}

__initcall(init_sys32_ioctl);

int register_ioctl32_conversion(unsigned int cmd,
                                ioctl_trans_handler_t handler)
{
        struct ioctl_trans *t;
        struct ioctl_trans *new_t;
        unsigned long hash = ioctl32_hash(cmd);

        new_t = kmalloc(sizeof(*new_t), GFP_KERNEL);
        if (!new_t)
                return -ENOMEM;

        down_write(&ioctl32_sem);
        for (t = ioctl32_hash_table[hash]; t; t = t->next) {
                if (t->cmd == cmd) {
                        printk(KERN_ERR "Trying to register duplicated ioctl32 "
                                        "handler %x\n", cmd);
                        up_write(&ioctl32_sem);
                        kfree(new_t);
                        return -EINVAL; 
                }
        }
        new_t->next = NULL;
        new_t->cmd = cmd;
        new_t->handler = handler;
        ioctl32_insert_translation(new_t);

        up_write(&ioctl32_sem);
        return 0;
}
EXPORT_SYMBOL(register_ioctl32_conversion);

static inline int builtin_ioctl(struct ioctl_trans *t)
{ 
        return t >= ioctl_start && t < (ioctl_start + ioctl_table_size);
} 

/* Problem: 
   This function cannot unregister duplicate ioctls, because they are not
   unique.
   When they happen we need to extend the prototype to pass the handler too. */

int unregister_ioctl32_conversion(unsigned int cmd)
{
        unsigned long hash = ioctl32_hash(cmd);
        struct ioctl_trans *t, *t1;

        down_write(&ioctl32_sem);

        t = ioctl32_hash_table[hash];
        if (!t) { 
                up_write(&ioctl32_sem);
                return -EINVAL;
        } 

        if (t->cmd == cmd) { 
                if (builtin_ioctl(t)) {
                        printk("%p tried to unregister builtin ioctl %x\n",
                               __builtin_return_address(0), cmd);
                } else { 
                        ioctl32_hash_table[hash] = t->next;
                        up_write(&ioctl32_sem);
                        kfree(t);
                        return 0;
                }
        } 
        while (t->next) {
                t1 = t->next;
                if (t1->cmd == cmd) { 
                        if (builtin_ioctl(t1)) {
                                printk("%p tried to unregister builtin "
                                        "ioctl %x\n",
                                        __builtin_return_address(0), cmd);
                                goto out;
                        } else { 
                                t->next = t1->next;
                                up_write(&ioctl32_sem);
                                kfree(t1);
                                return 0;
                        }
                }
                t = t1;
        }
        printk(KERN_ERR "Trying to free unknown 32bit ioctl handler %x\n",
                                cmd);
out:
        up_write(&ioctl32_sem);
        return -EINVAL;
}
EXPORT_SYMBOL(unregister_ioctl32_conversion); 

static void compat_ioctl_error(struct file *filp, unsigned int fd,
                unsigned int cmd, unsigned long arg)
{
        char buf[10];
        char *fn = "?";
        char *path;

        /* find the name of the device. */
        path = (char *)__get_free_page(GFP_KERNEL);
        if (path) {
                fn = d_path(filp->f_dentry, filp->f_vfsmnt, path, PAGE_SIZE);
                if (IS_ERR(fn))
                        fn = "?";
        }

        sprintf(buf,"'%c'", (cmd>>24) & 0x3f);
        if (!isprint(buf[1]))
                sprintf(buf, "%02x", buf[1]);
        printk("ioctl32(%s:%d): Unknown cmd fd(%d) "
                        "cmd(%08x){%s} arg(%08x) on %s\n",
                        current->comm, current->pid,
                        (int)fd, (unsigned int)cmd, buf,
                        (unsigned int)arg, fn);

        if (path)
                free_page((unsigned long)path);
}

asmlinkage long compat_sys_ioctl(unsigned int fd, unsigned int cmd,
                                unsigned long arg)
{
        struct file *filp;
        int error = -EBADF;
        struct ioctl_trans *t;
        int fput_needed;

        filp = fget_light(fd, &fput_needed);
        if (!filp)
                goto out;

        /* RED-PEN how should LSM module know it's handling 32bit? */
        error = security_file_ioctl(filp, cmd, arg);
        if (error)
                goto out_fput;

        /*
         * To allow the compat_ioctl handlers to be self contained
         * we need to check the common ioctls here first.
         * Just handle them with the standard handlers below.
         */
        switch (cmd) {
        case FIOCLEX:
        case FIONCLEX:
        case FIONBIO:
        case FIOASYNC:
        case FIOQSIZE:
                break;

        case FIBMAP:
        case FIGETBSZ:
        case FIONREAD:
                if (S_ISREG(filp->f_dentry->d_inode->i_mode))
                        break;
                /*FALL THROUGH*/

        default:
                if (filp->f_op && filp->f_op->compat_ioctl) {
                        error = filp->f_op->compat_ioctl(filp, cmd, arg);
                        if (error != -ENOIOCTLCMD)
                                goto out_fput;
                }

                if (!filp->f_op ||
                    (!filp->f_op->ioctl && !filp->f_op->unlocked_ioctl))
                        goto do_ioctl;
                break;
        }

        /* When register_ioctl32_conversion is finally gone remove
           this lock! -AK */
        down_read(&ioctl32_sem);
        for (t = ioctl32_hash_table[ioctl32_hash(cmd)]; t; t = t->next) {
                if (t->cmd == cmd)
                        goto found_handler;
        }
        up_read(&ioctl32_sem);

        if (S_ISSOCK(filp->f_dentry->d_inode->i_mode) &&
            cmd >= SIOCDEVPRIVATE && cmd <= (SIOCDEVPRIVATE + 15)) {
                error = siocdevprivate_ioctl(fd, cmd, arg);
        } else {
                static int count;

                if (++count <= 50)
                        compat_ioctl_error(filp, fd, cmd, arg);
                error = -EINVAL;
        }

        goto out_fput;

 found_handler:
        if (t->handler) {
                lock_kernel();
                error = t->handler(fd, cmd, arg, filp);
                unlock_kernel();
                up_read(&ioctl32_sem);
                goto out_fput;
        }

        up_read(&ioctl32_sem);
 do_ioctl:
        error = vfs_ioctl(filp, fd, cmd, arg);
 out_fput:
        fput_light(filp, fput_needed);
 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) {
                        if ((f.l_start >= COMPAT_OFF_T_MAX) ||
                            ((f.l_start + f.l_len) > COMPAT_OFF_T_MAX))
                                ret = -EOVERFLOW;
                        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) {
                        if ((f.l_start >= COMPAT_LOFF_T_MAX) ||
                            ((f.l_start + f.l_len) > COMPAT_LOFF_T_MAX))
                                ret = -EOVERFLOW;
                        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;
        }
        else {
                return -EINVAL;
        }

        return 0;
}

extern int copy_mount_options (const void __user *, unsigned long *);

#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) {
                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)))
#define COMPAT_ROUND_UP(x) (((x)+sizeof(compat_long_t)-1) & \
                                ~(sizeof(compat_long_t)-1))

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, ino_t ino, unsigned int d_type)
{
        struct compat_readdir_callback *buf = __buf;
        struct compat_old_linux_dirent __user *dirent;

        if (buf->result)
                return -EINVAL;
        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(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, ino_t ino, unsigned int d_type)
{
        struct compat_linux_dirent __user * dirent;
        struct compat_getdents_callback *buf = __buf;
        int reclen = COMPAT_ROUND_UP(NAME_OFFSET(dirent) + namlen + 2);

        buf->error = -EINVAL;   /* only used if we fail.. */
        if (reclen > buf->count)
                return -EINVAL;
        dirent = buf->previous;
        if (dirent) {
                if (__put_user(offset, &dirent->d_off))
                        goto efault;
        }
        dirent = buf->current_dir;
        if (__put_user(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
#define COMPAT_ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1))

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,
                     ino_t ino, unsigned int d_type)
{
        struct linux_dirent64 __user *dirent;
        struct compat_getdents_callback64 *buf = __buf;
        int jj = NAME_OFFSET(dirent);
        int reclen = COMPAT_ROUND_UP64(jj + namlen + 1);
        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;
                __put_user_unaligned(d_off, &lastdirent->d_off);
                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)
{
        typedef ssize_t (*io_fn_t)(struct file *, char __user *, size_t, loff_t *);
        typedef ssize_t (*iov_fn_t)(struct file *, const struct iovec *, unsigned long, loff_t *);

        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)
                goto out;

        fnv = NULL;
        if (type == READ) {
                fn = file->f_op->read;
                fnv = file->f_op->readv;
        } else {
                fn = (io_fn_t)file->f_op->write;
                fnv = file->f_op->writev;
        }
        if (fnv) {
                ret = fnv(file, iov, nr_segs, pos);
                goto out;
        }

        /* Do it by hand, with file-ops */
        ret = 0;
        vector = iov;
        while (nr_segs > 0) {
                void __user * base;
                size_t len;
                ssize_t nr;

                base = vector->iov_base;
                len = vector->iov_len;
                vector++;
                nr_segs--;

                nr = fn(file, base, len, pos);

                if (nr < 0) {
                        if (!ret) ret = nr;
                        break;
                }
                ret += nr;
                if (nr != len)
                        break;
        }
out:
        if (iov != iovstack)
                kfree(iov);
        if ((ret + (type == READ)) > 0)
                dnotify_parent(file->f_dentry,
                                (type == READ) ? DN_ACCESS : DN_MODIFY);
        return ret;
}

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->readv && !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->writev && !file->f_op->write))
                goto out;

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

out:
        fput(file);
        return ret;
}

/*
 * 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;
        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), bprm->p))) {
                        ret = -EFAULT;
                        goto out;
                }

                if (bprm->p < len)  {
                        ret = -E2BIG;
                        goto out;
                }

                bprm->p -= len;
                /* XXX: add architecture specific overflow check here. */
                pos = bprm->p;

                while (len > 0) {
                        int i, new, err;
                        int offset, bytes_to_copy;
                        struct page *page;

                        offset = pos % PAGE_SIZE;
                        i = pos/PAGE_SIZE;
                        page = bprm->page[i];
                        new = 0;
                        if (!page) {
                                page = alloc_page(GFP_HIGHUSER);
                                bprm->page[i] = page;
                                if (!page) {
                                        ret = -ENOMEM;
                                        goto out;
                                }
                                new = 1;
                        }

                        if (page != kmapped_page) {
                                if (kmapped_page)
                                        kunmap(kmapped_page);
                                kmapped_page = page;
                                kaddr = kmap(kmapped_page);
                        }
                        if (new && offset)
                                memset(kaddr, 0, offset);
                        bytes_to_copy = PAGE_SIZE - offset;
                        if (bytes_to_copy > len) {
                                bytes_to_copy = len;
                                if (new)
                                        memset(kaddr+offset+len, 0,
                                                PAGE_SIZE-offset-len);
                        }
                        err = copy_from_user(kaddr+offset, compat_ptr(str),
                                                bytes_to_copy);
                        if (err) {
                                ret = -EFAULT;
                                goto out;
                        }

                        pos += bytes_to_copy;
                        str += bytes_to_copy;
                        len -= bytes_to_copy;
                }
        }
        ret = 0;
out:
        if (kmapped_page)
                kunmap(kmapped_page);
        return ret;
}

#ifdef CONFIG_MMU

#define free_arg_pages(bprm) do { } while (0)

#else

static inline void free_arg_pages(struct linux_binprm *bprm)
{
        int i;

        for (i = 0; i < MAX_ARG_PAGES; i++) {
                if (bprm->page[i])
                        __free_page(bprm->page[i]);
                bprm->page[i] = NULL;
        }
}

#endif /* CONFIG_MMU */

/*
 * 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;
        int i;

        retval = -ENOMEM;
        bprm = kmalloc(sizeof(*bprm), GFP_KERNEL);
        if (!bprm)
                goto out_ret;
        memset(bprm, 0, sizeof(*bprm));

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

        sched_exec();

        bprm->p = PAGE_SIZE*MAX_ARG_PAGES-sizeof(void *);
        bprm->file = file;
        bprm->filename = filename;
        bprm->interp = filename;
        bprm->mm = mm_alloc();
        retval = -ENOMEM;
        if (!bprm->mm)
                goto out_file;

        retval = init_new_context(current, bprm->mm);
        if (retval < 0)
                goto out_mm;

        bprm->argc = compat_count(argv, bprm->p / sizeof(compat_uptr_t));
        if ((retval = bprm->argc) < 0)
                goto out_mm;

        bprm->envc = compat_count(envp, bprm->p / sizeof(compat_uptr_t));
        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) {
                free_arg_pages(bprm);

                /* execve success */
                security_bprm_free(bprm);
                kfree(bprm);
                return retval;
        }

out:
        /* Something went wrong, return the inode and free the argument pages*/
        for (i = 0 ; i < MAX_ARG_PAGES ; i++) {
                struct page * page = bprm->page[i];
                if (page)
                        __free_page(page);
        }

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

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

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

out_kfree:
        kfree(bprm);

out_ret:
        return retval;
}

#define __COMPAT_NFDBITS       (8 * sizeof(compat_ulong_t))

#define ROUND_UP(x,y) (((x)+(y)-1)/(y))

/*
 * Ooo, nasty.  We need here to frob 32-bit unsigned longs to
 * 64-bit unsigned longs.
 */
static inline
int compat_get_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
                        unsigned long *fdset)
{
        nr = 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;
                        __get_user(l, ufdset);
                        __get_user(h, ufdset+1);
                        ufdset += 2;
                        *fdset++ = h << 32 | l;
                        nr -= 2;
                }
                if (odd)
                        __get_user(*fdset, ufdset);
        } 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 inline
void compat_set_fd_set(unsigned long nr, compat_ulong_t __user *ufdset,
                        unsigned long *fdset)
{
        unsigned long odd;
        nr = ROUND_UP(nr, __COMPAT_NFDBITS);

        if (!ufdset)
                return;

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


/*
 * This is a virtual copy of sys_select from fs/select.c and probably
 * should be compared to it from time to time
 */
static void *select_bits_alloc(int size)
{
        return kmalloc(6 * size, GFP_KERNEL);
}

static void select_bits_free(void *bits, int size)
{
        kfree(bits);
}

/*
 * 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)

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)
{
        fd_set_bits fds;
        char *bits;
        long timeout;
        int size, max_fdset, ret = -EINVAL;

        timeout = MAX_SCHEDULE_TIMEOUT;
        if (tvp) {
                time_t sec, usec;

                if (!access_ok(VERIFY_READ, tvp, sizeof(*tvp))
                    || __get_user(sec, &tvp->tv_sec)
                    || __get_user(usec, &tvp->tv_usec)) {
                        ret = -EFAULT;
                        goto out_nofds;
                }

                if (sec < 0 || usec < 0)
                        goto out_nofds;

                if ((unsigned long) sec < MAX_SELECT_SECONDS) {
                        timeout = ROUND_UP(usec, 1000000/HZ);
                        timeout += sec * (unsigned long) HZ;
                }
        }

        if (n < 0)
                goto out_nofds;

        /* max_fdset can increase, so grab it once to avoid race */
        max_fdset = current->files->max_fdset;
        if (n > max_fdset)
                n = max_fdset;

        /*
         * 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.
         */
        ret = -ENOMEM;
        size = FDS_BYTES(n);
        bits = select_bits_alloc(size);
        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 (tvp && !(current->personality & STICKY_TIMEOUTS)) {
                time_t sec = 0, usec = 0;
                if (timeout) {
                        sec = timeout / HZ;
                        usec = timeout % HZ;
                        usec *= (1000000/HZ);
                }
                if (put_user(sec, &tvp->tv_sec) ||
                    put_user(usec, &tvp->tv_usec))
                        ret = -EFAULT;
        }

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

        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);

out:
        select_bits_free(bits, size);
out_nofds:
        return ret;
}

#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)
{
        int err;

        err = access_ok(VERIFY_READ, &arg->ca32_svc, sizeof(arg->ca32_svc));
        err |= get_user(karg->ca_version, &arg->ca32_version);
        err |= __get_user(karg->ca_svc.svc_port, &arg->ca32_svc.svc32_port);
        err |= __get_user(karg->ca_svc.svc_nthreads, &arg->ca32_svc.svc32_nthreads);
        return (err) ? -EFAULT : 0;
}

static int compat_nfs_clnt_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
{
        int err;

        err = access_ok(VERIFY_READ, &arg->ca32_client, sizeof(arg->ca32_client));
        err |= get_user(karg->ca_version, &arg->ca32_version);
        err |= __copy_from_user(&karg->ca_client.cl_ident[0],
                          &arg->ca32_client.cl32_ident[0],
                          NFSCLNT_IDMAX);
        err |= __get_user(karg->ca_client.cl_naddr, &arg->ca32_client.cl32_naddr);
        err |= __copy_from_user(&karg->ca_client.cl_addrlist[0],
                          &arg->ca32_client.cl32_addrlist[0],
                          (sizeof(struct in_addr) * NFSCLNT_ADDRMAX));
        err |= __get_user(karg->ca_client.cl_fhkeytype,
                      &arg->ca32_client.cl32_fhkeytype);
        err |= __get_user(karg->ca_client.cl_fhkeylen,
                      &arg->ca32_client.cl32_fhkeylen);
        err |= __copy_from_user(&karg->ca_client.cl_fhkey[0],
                          &arg->ca32_client.cl32_fhkey[0],
                          NFSCLNT_KEYMAX);

        return (err) ? -EFAULT : 0;
}

static int compat_nfs_exp_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
{
        int err;

        err = access_ok(VERIFY_READ, &arg->ca32_export, sizeof(arg->ca32_export));
        err |= get_user(karg->ca_version, &arg->ca32_version);
        err |= __copy_from_user(&karg->ca_export.ex_client[0],
                          &arg->ca32_export.ex32_client[0],
                          NFSCLNT_IDMAX);
        err |= __copy_from_user(&karg->ca_export.ex_path[0],
                          &arg->ca32_export.ex32_path[0],
                          NFS_MAXPATHLEN);
        err |= __get_user(karg->ca_export.ex_dev,
                      &arg->ca32_export.ex32_dev);
        err |= __get_user(karg->ca_export.ex_ino,
                      &arg->ca32_export.ex32_ino);
        err |= __get_user(karg->ca_export.ex_flags,
                      &arg->ca32_export.ex32_flags);
        err |= __get_user(karg->ca_export.ex_anon_uid,
                      &arg->ca32_export.ex32_anon_uid);
        err |= __get_user(karg->ca_export.ex_anon_gid,
                      &arg->ca32_export.ex32_anon_gid);
        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 (err) ? -EFAULT : 0;
}

static int compat_nfs_getfd_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
{
        int err;

        err = access_ok(VERIFY_READ, &arg->ca32_getfd, sizeof(arg->ca32_getfd));
        err |= get_user(karg->ca_version, &arg->ca32_version);
        err |= __copy_from_user(&karg->ca_getfd.gd_addr,
                          &arg->ca32_getfd.gd32_addr,
                          (sizeof(struct sockaddr)));
        err |= __copy_from_user(&karg->ca_getfd.gd_path,
                          &arg->ca32_getfd.gd32_path,
                          (NFS_MAXPATHLEN+1));
        err |= __get_user(karg->ca_getfd.gd_version,
                      &arg->ca32_getfd.gd32_version);

        return (err) ? -EFAULT : 0;
}

static int compat_nfs_getfs_trans(struct nfsctl_arg *karg, struct compat_nfsctl_arg __user *arg)
{
        int err;

        err = access_ok(VERIFY_READ, &arg->ca32_getfs, sizeof(arg->ca32_getfs));
        err |= get_user(karg->ca_version, &arg->ca32_version);
        err |= __copy_from_user(&karg->ca_getfs.gd_addr,
                          &arg->ca32_getfs.gd32_addr,
                          (sizeof(struct sockaddr)));
        err |= __copy_from_user(&karg->ca_getfs.gd_path,
                          &arg->ca32_getfs.gd32_path,
                          (NFS_MAXPATHLEN+1));
        err |= __get_user(karg->ca_getfs.gd_maxlen,
                      &arg->ca32_getfs.gd32_maxlen);

        return (err) ? -EFAULT : 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;
                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