/*
 *  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@ucw.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/stddef.h>
#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/ncp_mount.h>
#include <linux/nfs4_mount.h>
#include <linux/syscalls.h>
#include <linux/ctype.h>
#include <linux/dirent.h>
#include <linux/fsnotify.h>
#include <linux/highuid.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/fs_struct.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/aio.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;
}

/*
 * Not all architectures have sys_utime, so implement this in terms
 * of sys_utimes.
 */
asmlinkage long compat_sys_utime(const 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, const 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[1].tv_nsec == UTIME_OMIT)
                        return 0;
        }
        return do_utimes(dfd, filename, t ? tv : NULL, flags);
}

asmlinkage long compat_sys_futimesat(unsigned int dfd, const 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(const 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)
{
        struct compat_stat tmp;

        if (!old_valid_dev(stat->dev) || !old_valid_dev(stat->rdev))
                return -EOVERFLOW;

        memset(&tmp, 0, sizeof(tmp));
        tmp.st_dev = old_encode_dev(stat->dev);
        tmp.st_ino = stat->ino;
        if (sizeof(tmp.st_ino) < sizeof(stat->ino) && tmp.st_ino != stat->ino)
                return -EOVERFLOW;
        tmp.st_mode = stat->mode;
        tmp.st_nlink = stat->nlink;
        if (tmp.st_nlink != stat->nlink)
                return -EOVERFLOW;
        SET_UID(tmp.st_uid, from_kuid_munged(current_user_ns(), stat->uid));
        SET_GID(tmp.st_gid, from_kgid_munged(current_user_ns(), stat->gid));
        tmp.st_rdev = old_encode_dev(stat->rdev);
        if ((u64) stat->size > MAX_NON_LFS)
                return -EOVERFLOW;
        tmp.st_size = stat->size;
        tmp.st_atime = stat->atime.tv_sec;
        tmp.st_atime_nsec = stat->atime.tv_nsec;
        tmp.st_mtime = stat->mtime.tv_sec;
        tmp.st_mtime_nsec = stat->mtime.tv_nsec;
        tmp.st_ctime = stat->ctime.tv_sec;
        tmp.st_ctime_nsec = stat->ctime.tv_nsec;
        tmp.st_blocks = stat->blocks;
        tmp.st_blksize = stat->blksize;
        return copy_to_user(ubuf, &tmp, sizeof(tmp)) ? -EFAULT : 0;
}

asmlinkage long compat_sys_newstat(const char __user * filename,
                struct compat_stat __user *statbuf)
{
        struct kstat stat;
        int error;

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

asmlinkage long compat_sys_newlstat(const char __user * filename,
                struct compat_stat __user *statbuf)
{
        struct kstat stat;
        int error;

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

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

        error = vfs_fstatat(dfd, filename, &stat, flag);
        if (error)
                return error;
        return cp_compat_stat(&stat, statbuf);
}
#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(kbuf->f_flags, &ubuf->f_flags) ||
            __clear_user(ubuf->f_spare, sizeof(ubuf->f_spare)))
                return -EFAULT;
        return 0;
}

/*
 * The following statfs calls are copies of code from fs/statfs.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 kstatfs tmp;
        int error = user_statfs(pathname, &tmp);
        if (!error)
                error = put_compat_statfs(buf, &tmp);
        return error;
}

asmlinkage long compat_sys_fstatfs(unsigned int fd, struct compat_statfs __user *buf)
{
        struct kstatfs tmp;
        int error = fd_statfs(fd, &tmp);
        if (!error)
                error = put_compat_statfs(buf, &tmp);
        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) ||
            __put_user(kbuf->f_flags, &ubuf->f_flags) ||
            __clear_user(ubuf->f_spare, sizeof(ubuf->f_spare)))
                return -EFAULT;
        return 0;
}

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

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

        error = user_statfs(pathname, &tmp);
        if (!error)
                error = put_compat_statfs64(buf, &tmp);
        return error;
}

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

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

        error = fd_statfs(fd, &tmp);
        if (!error)
                error = put_compat_statfs64(buf, &tmp);
        return error;
}

/*
 * This is a copy of sys_ustat, just dealing with a structure layout.
 * Given how simple this syscall is that apporach is more maintainable
 * than the various conversion hacks.
 */
asmlinkage long compat_sys_ustat(unsigned dev, struct compat_ustat __user *u)
{
        struct compat_ustat tmp;
        struct kstatfs sbuf;
        int err = vfs_ustat(new_decode_dev(dev), &sbuf);
        if (err)
                return err;

        memset(&tmp, 0, sizeof(struct compat_ustat));
        tmp.f_tfree = sbuf.f_bfree;
        tmp.f_tinode = sbuf.f_ffree;
        if (copy_to_user(u, &tmp, sizeof(struct compat_ustat)))
                return -EFAULT;
        return 0;
}

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 successful 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;
}

/* A write operation does a read from user space and vice versa */
#define vrfy_dir(type) ((type) == READ ? VERIFY_WRITE : VERIFY_READ)

ssize_t compat_rw_copy_check_uvector(int type,
                const struct compat_iovec __user *uvector, unsigned long nr_segs,
                unsigned long fast_segs, struct iovec *fast_pointer,
                struct iovec **ret_pointer)
{
        compat_ssize_t tot_len;
        struct iovec *iov = *ret_pointer = fast_pointer;
        ssize_t ret = 0;
        int seg;

        /*
         * 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...
         */
        if (nr_segs == 0)
                goto out;

        ret = -EINVAL;
        if (nr_segs > UIO_MAXIOV || nr_segs < 0)
                goto out;
        if (nr_segs > fast_segs) {
                ret = -ENOMEM;
                iov = kmalloc(nr_segs*sizeof(struct iovec), GFP_KERNEL);
                if (iov == NULL)
                        goto out;
        }
        *ret_pointer = iov;

        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.
         *
         * In Linux, the total length is limited to MAX_RW_COUNT, there is
         * no overflow possibility.
         */
        tot_len = 0;
        ret = -EINVAL;
        for (seg = 0; seg < nr_segs; seg++) {
                compat_uptr_t buf;
                compat_ssize_t len;

                if (__get_user(len, &uvector->iov_len) ||
                   __get_user(buf, &uvector->iov_base)) {
                        ret = -EFAULT;
                        goto out;
                }
                if (len < 0)    /* size_t not fitting in compat_ssize_t .. */
                        goto out;
                if (type >= 0 &&
                    !access_ok(vrfy_dir(type), compat_ptr(buf), len)) {
                        ret = -EFAULT;
                        goto out;
                }
                if (len > MAX_RW_COUNT - tot_len)
                        len = MAX_RW_COUNT - tot_len;
                tot_len += len;
                iov->iov_base = compat_ptr(buf);
                iov->iov_len = (compat_size_t) len;
                uvector++;
                iov++;
        }
        ret = tot_len;

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 = do_io_submit(ctx_id, nr, iocb64, 1);
        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_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 NCPFS_NAME      "ncpfs"
#define NFS4_NAME       "nfs4"

asmlinkage long compat_sys_mount(const char __user * dev_name,
                                 const char __user * dir_name,
                                 const char __user * type, unsigned long flags,
                                 const void __user * data)
{
        char *kernel_type;
        unsigned long data_page;
        char *kernel_dev;
        struct filename *dir;
        int retval;

        retval = copy_mount_string(type, &kernel_type);
        if (retval < 0)
                goto out;

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

        retval = copy_mount_string(dev_name, &kernel_dev);
        if (retval < 0)
                goto out2;

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

        retval = -EINVAL;

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

        retval = do_mount(kernel_dev, dir->name, kernel_type,
                        flags, (void*)data_page);

 out4:
        free_page(data_page);
 out3:
        kfree(kernel_dev);
 out2:
        putname(dir);
 out1:
        kfree(kernel_type);
 out:
        return retval;
}

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 dir_context ctx;
        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 fd f = fdget(fd);
        struct compat_readdir_callback buf = {
                .ctx.actor = compat_fillonedir,
                .dirent = dirent
        };

        if (!f.file)
                return -EBADF;

        error = iterate_dir(f.file, &buf.ctx);
        if (buf.result)
                error = buf.result;

        fdput(f);
        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 dir_context ctx;
        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(offsetof(struct compat_linux_dirent, d_name) +
                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 fd f;
        struct compat_linux_dirent __user * lastdirent;
        struct compat_getdents_callback buf = {
                .ctx.actor = compat_filldir,
                .current_dir = dirent,
                .count = count
        };
        int error;

        if (!access_ok(VERIFY_WRITE, dirent, count))
                return -EFAULT;

        f = fdget(fd);
        if (!f.file)
                return -EBADF;

        error = iterate_dir(f.file, &buf.ctx);
        if (error >= 0)
                error = buf.error;
        lastdirent = buf.previous;
        if (lastdirent) {
                if (put_user(buf.ctx.pos, &lastdirent->d_off))
                        error = -EFAULT;
                else
                        error = count - buf.count;
        }
        fdput(f);
        return error;
}

#ifndef __ARCH_OMIT_COMPAT_SYS_GETDENTS64

struct compat_getdents_callback64 {
        struct dir_context ctx;
        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 reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + 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 fd f;
        struct linux_dirent64 __user * lastdirent;
        struct compat_getdents_callback64 buf = {
                .ctx.actor = compat_filldir64,
                .current_dir = dirent,
                .count = count
        };
        int error;

        if (!access_ok(VERIFY_WRITE, dirent, count))
                return -EFAULT;

        f = fdget(fd);
        if (!f.file)
                return -EBADF;

        error = iterate_dir(f.file, &buf.ctx);
        if (error >= 0)
                error = buf.error;
        lastdirent = buf.previous;
        if (lastdirent) {
                typeof(lastdirent->d_off) d_off = buf.ctx.pos;
                if (__put_user_unaligned(d_off, &lastdirent->d_off))
                        error = -EFAULT;
                else
                        error = count - buf.count;
        }
        fdput(f);
        return error;
}
#endif /* ! __ARCH_OMIT_COMPAT_SYS_GETDENTS64 */

/*
 * Exactly like fs/open.c:sys_open(), except that it doesn't set the
 * O_LARGEFILE flag.
 */
COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, 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.
 */
COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode)
{
        return do_sys_open(dfd, filename, flags, mode);
}

#define __COMPAT_NFDBITS       (8 * sizeof(compat_ulong_t))

static int poll_select_copy_remaining(struct timespec *end_time, void __user *p,
                                      int timeval, int ret)
{
        struct timespec ts;

        if (!p)
                return ret;

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

        /* No update for zero timeout */
        if (!end_time->tv_sec && !end_time->tv_nsec)
                return ret;

        ktime_get_ts(&ts);
        ts = timespec_sub(*end_time, ts);
        if (ts.tv_sec < 0)
                ts.tv_sec = ts.tv_nsec = 0;

        if (timeval) {
                struct compat_timeval rtv;

                rtv.tv_sec = ts.tv_sec;
                rtv.tv_usec = ts.tv_nsec / NSEC_PER_USEC;

                if (!copy_to_user(p, &rtv, sizeof(rtv)))
                        return ret;
        } else {
                struct compat_timespec rts;

                rts.tv_sec = ts.tv_sec;
                rts.tv_nsec = ts.tv_nsec;

                if (!copy_to_user(p, &rts, sizeof(rts)))
                        return ret;
        }
        /*
         * 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.
         */

sticky:
        if (ret == -ERESTARTNOHAND)
                ret = -EINTR;
        return ret;
}

/*
 * 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.
 */
int compat_core_sys_select(int n, compat_ulong_t __user *inp,
        compat_ulong_t __user *outp, compat_ulong_t __user *exp,
        struct timespec *end_time)
{
        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, end_time);

        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)
{
        struct timespec end_time, *to = NULL;
        struct compat_timeval tv;
        int ret;

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

                to = &end_time;
                if (poll_select_set_timeout(to,
                                tv.tv_sec + (tv.tv_usec / USEC_PER_SEC),
                                (tv.tv_usec % USEC_PER_SEC) * NSEC_PER_USEC))
                        return -EINVAL;
        }

        ret = compat_core_sys_select(n, inp, outp, exp, to);
        ret = poll_select_copy_remaining(&end_time, tvp, 1, ret);

        return ret;
}

struct compat_sel_arg_struct {
        compat_ulong_t n;
        compat_uptr_t inp;
        compat_uptr_t outp;
        compat_uptr_t exp;
        compat_uptr_t tvp;
};

asmlinkage long compat_sys_old_select(struct compat_sel_arg_struct __user *arg)
{
        struct compat_sel_arg_struct a;

        if (copy_from_user(&a, arg, sizeof(a)))
                return -EFAULT;
        return compat_sys_select(a.n, compat_ptr(a.inp), compat_ptr(a.outp),
                                 compat_ptr(a.exp), compat_ptr(a.tvp));
}

static long do_compat_pselect(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;
        struct compat_timespec ts;
        struct timespec end_time, *to = NULL;
        int ret;

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

                to = &end_time;
                if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
                        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);
        }

        ret = compat_core_sys_select(n, inp, outp, exp, to);
        ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);

        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 do_compat_pselect(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;
        struct timespec end_time, *to = NULL;
        int ret;

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

                to = &end_time;
                if (poll_select_set_timeout(to, ts.tv_sec, ts.tv_nsec))
                        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);
        }

        ret = do_sys_poll(ufds, nfds, to);

        /* 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);

        ret = poll_select_copy_remaining(&end_time, tsp, 0, ret);

        return ret;
}

#ifdef CONFIG_FHANDLE
/*
 * Exactly like fs/open.c:sys_open_by_handle_at(), except that it
 * doesn't set the O_LARGEFILE flag.
 */
COMPAT_SYSCALL_DEFINE3(open_by_handle_at, int, mountdirfd,
                             struct file_handle __user *, handle, int, flags)
{
        return do_handle_open(mountdirfd, handle, flags);
}
#endif