/*
    comedi/comedi_compat32.c
    32-bit ioctl compatibility for 64-bit comedi kernel module.

    Author: Ian Abbott, MEV Ltd. <abbotti@mev.co.uk>
    Copyright (C) 2007 MEV Ltd. <http://www.mev.co.uk/>

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 1997-2007 David A. Schleef <ds@schleef.org>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#define __NO_VERSION__
#include "comedi.h"
#include <linux/smp_lock.h>
#include <asm/uaccess.h>

#include "comedi_compat32.h"

#ifdef CONFIG_COMPAT

#ifndef HAVE_COMPAT_IOCTL
#include <linux/ioctl32.h>      /* for (un)register_ioctl32_conversion */
#endif

#define COMEDI32_CHANINFO _IOR(CIO, 3, struct comedi32_chaninfo_struct)
#define COMEDI32_RANGEINFO _IOR(CIO, 8, struct comedi32_rangeinfo_struct)
/* N.B. COMEDI32_CMD and COMEDI_CMD ought to use _IOWR, not _IOR.
 * It's too late to change it now, but it only affects the command number. */
#define COMEDI32_CMD _IOR(CIO, 9, struct comedi32_cmd_struct)
/* N.B. COMEDI32_CMDTEST and COMEDI_CMDTEST ought to use _IOWR, not _IOR.
 * It's too late to change it now, but it only affects the command number. */
#define COMEDI32_CMDTEST _IOR(CIO, 10, struct comedi32_cmd_struct)
#define COMEDI32_INSNLIST _IOR(CIO, 11, struct comedi32_insnlist_struct)
#define COMEDI32_INSN _IOR(CIO, 12, struct comedi32_insn_struct)

struct comedi32_chaninfo_struct {
        unsigned int subdev;
        compat_uptr_t maxdata_list;     /* 32-bit 'unsigned int *' */
        compat_uptr_t flaglist; /* 32-bit 'unsigned int *' */
        compat_uptr_t rangelist;        /* 32-bit 'unsigned int *' */
        unsigned int unused[4];
};

struct comedi32_rangeinfo_struct {
        unsigned int range_type;
        compat_uptr_t range_ptr;        /* 32-bit 'void *' */
};

struct comedi32_cmd_struct {
        unsigned int subdev;
        unsigned int flags;
        unsigned int start_src;
        unsigned int start_arg;
        unsigned int scan_begin_src;
        unsigned int scan_begin_arg;
        unsigned int convert_src;
        unsigned int convert_arg;
        unsigned int scan_end_src;
        unsigned int scan_end_arg;
        unsigned int stop_src;
        unsigned int stop_arg;
        compat_uptr_t chanlist; /* 32-bit 'unsigned int *' */
        unsigned int chanlist_len;
        compat_uptr_t data;     /* 32-bit 'short *' */
        unsigned int data_len;
};

struct comedi32_insn_struct {
        unsigned int insn;
        unsigned int n;
        compat_uptr_t data;     /* 32-bit 'unsigned int *' */
        unsigned int subdev;
        unsigned int chanspec;
        unsigned int unused[3];
};

struct comedi32_insnlist_struct {
        unsigned int n_insns;
        compat_uptr_t insns;    /* 32-bit 'struct comedi_insn *' */
};

/* Handle translated ioctl. */
static int translated_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
        if (!file->f_op)
                return -ENOTTY;

#ifdef HAVE_UNLOCKED_IOCTL
        if (file->f_op->unlocked_ioctl) {
                int rc = (int)(*file->f_op->unlocked_ioctl) (file, cmd, arg);
                if (rc == -ENOIOCTLCMD)
                        rc = -ENOTTY;
                return rc;
        }
#endif
        if (file->f_op->ioctl) {
                int rc;
                lock_kernel();
                rc = (*file->f_op->ioctl) (file->f_dentry->d_inode,
                                           file, cmd, arg);
                unlock_kernel();
                return rc;
        }
        return -ENOTTY;
}

/* Handle 32-bit COMEDI_CHANINFO ioctl. */
static int compat_chaninfo(struct file *file, unsigned long arg)
{
        struct comedi_chaninfo __user *chaninfo;
        struct comedi32_chaninfo_struct __user *chaninfo32;
        int err;
        union {
                unsigned int uint;
                compat_uptr_t uptr;
        } temp;

        chaninfo32 = compat_ptr(arg);
        chaninfo = compat_alloc_user_space(sizeof(*chaninfo));

        /* Copy chaninfo structure.  Ignore unused members. */
        if (!access_ok(VERIFY_READ, chaninfo32, sizeof(*chaninfo32))
            || !access_ok(VERIFY_WRITE, chaninfo, sizeof(*chaninfo))) {
                return -EFAULT;
        }
        err = 0;
        err |= __get_user(temp.uint, &chaninfo32->subdev);
        err |= __put_user(temp.uint, &chaninfo->subdev);
        err |= __get_user(temp.uptr, &chaninfo32->maxdata_list);
        err |= __put_user(compat_ptr(temp.uptr), &chaninfo->maxdata_list);
        err |= __get_user(temp.uptr, &chaninfo32->flaglist);
        err |= __put_user(compat_ptr(temp.uptr), &chaninfo->flaglist);
        err |= __get_user(temp.uptr, &chaninfo32->rangelist);
        err |= __put_user(compat_ptr(temp.uptr), &chaninfo->rangelist);
        if (err)
                return -EFAULT;

        return translated_ioctl(file, COMEDI_CHANINFO, (unsigned long)chaninfo);
}

/* Handle 32-bit COMEDI_RANGEINFO ioctl. */
static int compat_rangeinfo(struct file *file, unsigned long arg)
{
        struct comedi_rangeinfo __user *rangeinfo;
        struct comedi32_rangeinfo_struct __user *rangeinfo32;
        int err;
        union {
                unsigned int uint;
                compat_uptr_t uptr;
        } temp;

        rangeinfo32 = compat_ptr(arg);
        rangeinfo = compat_alloc_user_space(sizeof(*rangeinfo));

        /* Copy rangeinfo structure. */
        if (!access_ok(VERIFY_READ, rangeinfo32, sizeof(*rangeinfo32))
            || !access_ok(VERIFY_WRITE, rangeinfo, sizeof(*rangeinfo))) {
                return -EFAULT;
        }
        err = 0;
        err |= __get_user(temp.uint, &rangeinfo32->range_type);
        err |= __put_user(temp.uint, &rangeinfo->range_type);
        err |= __get_user(temp.uptr, &rangeinfo32->range_ptr);
        err |= __put_user(compat_ptr(temp.uptr), &rangeinfo->range_ptr);
        if (err)
                return -EFAULT;

        return translated_ioctl(file, COMEDI_RANGEINFO,
                                (unsigned long)rangeinfo);
}

/* Copy 32-bit cmd structure to native cmd structure. */
static int get_compat_cmd(struct comedi_cmd __user * cmd,
                          struct comedi32_cmd_struct __user * cmd32)
{
        int err;
        union {
                unsigned int uint;
                compat_uptr_t uptr;
        } temp;

        /* Copy cmd structure. */
        if (!access_ok(VERIFY_READ, cmd32, sizeof(*cmd32))
            || !access_ok(VERIFY_WRITE, cmd, sizeof(*cmd))) {
                return -EFAULT;
        }
        err = 0;
        err |= __get_user(temp.uint, &cmd32->subdev);
        err |= __put_user(temp.uint, &cmd->subdev);
        err |= __get_user(temp.uint, &cmd32->flags);
        err |= __put_user(temp.uint, &cmd->flags);
        err |= __get_user(temp.uint, &cmd32->start_src);
        err |= __put_user(temp.uint, &cmd->start_src);
        err |= __get_user(temp.uint, &cmd32->start_arg);
        err |= __put_user(temp.uint, &cmd->start_arg);
        err |= __get_user(temp.uint, &cmd32->scan_begin_src);
        err |= __put_user(temp.uint, &cmd->scan_begin_src);
        err |= __get_user(temp.uint, &cmd32->scan_begin_arg);
        err |= __put_user(temp.uint, &cmd->scan_begin_arg);
        err |= __get_user(temp.uint, &cmd32->convert_src);
        err |= __put_user(temp.uint, &cmd->convert_src);
        err |= __get_user(temp.uint, &cmd32->convert_arg);
        err |= __put_user(temp.uint, &cmd->convert_arg);
        err |= __get_user(temp.uint, &cmd32->scan_end_src);
        err |= __put_user(temp.uint, &cmd->scan_end_src);
        err |= __get_user(temp.uint, &cmd32->scan_end_arg);
        err |= __put_user(temp.uint, &cmd->scan_end_arg);
        err |= __get_user(temp.uint, &cmd32->stop_src);
        err |= __put_user(temp.uint, &cmd->stop_src);
        err |= __get_user(temp.uint, &cmd32->stop_arg);
        err |= __put_user(temp.uint, &cmd->stop_arg);
        err |= __get_user(temp.uptr, &cmd32->chanlist);
        err |= __put_user(compat_ptr(temp.uptr), &cmd->chanlist);
        err |= __get_user(temp.uint, &cmd32->chanlist_len);
        err |= __put_user(temp.uint, &cmd->chanlist_len);
        err |= __get_user(temp.uptr, &cmd32->data);
        err |= __put_user(compat_ptr(temp.uptr), &cmd->data);
        err |= __get_user(temp.uint, &cmd32->data_len);
        err |= __put_user(temp.uint, &cmd->data_len);
        return err ? -EFAULT : 0;
}

/* Copy native cmd structure to 32-bit cmd structure. */
static int put_compat_cmd(struct comedi32_cmd_struct __user * cmd32,
                          struct comedi_cmd __user * cmd)
{
        int err;
        unsigned int temp;

        /* Copy back most of cmd structure. */
        /* Assume the pointer values are already valid. */
        /* (Could use ptr_to_compat() to set them, but that wasn't implemented
         * until kernel version 2.6.11.) */
        if (!access_ok(VERIFY_READ, cmd, sizeof(*cmd))
            || !access_ok(VERIFY_WRITE, cmd32, sizeof(*cmd32))) {
                return -EFAULT;
        }
        err = 0;
        err |= __get_user(temp, &cmd->subdev);
        err |= __put_user(temp, &cmd32->subdev);
        err |= __get_user(temp, &cmd->flags);
        err |= __put_user(temp, &cmd32->flags);
        err |= __get_user(temp, &cmd->start_src);
        err |= __put_user(temp, &cmd32->start_src);
        err |= __get_user(temp, &cmd->start_arg);
        err |= __put_user(temp, &cmd32->start_arg);
        err |= __get_user(temp, &cmd->scan_begin_src);
        err |= __put_user(temp, &cmd32->scan_begin_src);
        err |= __get_user(temp, &cmd->scan_begin_arg);
        err |= __put_user(temp, &cmd32->scan_begin_arg);
        err |= __get_user(temp, &cmd->convert_src);
        err |= __put_user(temp, &cmd32->convert_src);
        err |= __get_user(temp, &cmd->convert_arg);
        err |= __put_user(temp, &cmd32->convert_arg);
        err |= __get_user(temp, &cmd->scan_end_src);
        err |= __put_user(temp, &cmd32->scan_end_src);
        err |= __get_user(temp, &cmd->scan_end_arg);
        err |= __put_user(temp, &cmd32->scan_end_arg);
        err |= __get_user(temp, &cmd->stop_src);
        err |= __put_user(temp, &cmd32->stop_src);
        err |= __get_user(temp, &cmd->stop_arg);
        err |= __put_user(temp, &cmd32->stop_arg);
        /* Assume chanlist pointer is unchanged. */
        err |= __get_user(temp, &cmd->chanlist_len);
        err |= __put_user(temp, &cmd32->chanlist_len);
        /* Assume data pointer is unchanged. */
        err |= __get_user(temp, &cmd->data_len);
        err |= __put_user(temp, &cmd32->data_len);
        return err ? -EFAULT : 0;
}

/* Handle 32-bit COMEDI_CMD ioctl. */
static int compat_cmd(struct file *file, unsigned long arg)
{
        struct comedi_cmd __user *cmd;
        struct comedi32_cmd_struct __user *cmd32;
        int rc;

        cmd32 = compat_ptr(arg);
        cmd = compat_alloc_user_space(sizeof(*cmd));

        rc = get_compat_cmd(cmd, cmd32);
        if (rc)
                return rc;

        return translated_ioctl(file, COMEDI_CMD, (unsigned long)cmd);
}

/* Handle 32-bit COMEDI_CMDTEST ioctl. */
static int compat_cmdtest(struct file *file, unsigned long arg)
{
        struct comedi_cmd __user *cmd;
        struct comedi32_cmd_struct __user *cmd32;
        int rc, err;

        cmd32 = compat_ptr(arg);
        cmd = compat_alloc_user_space(sizeof(*cmd));

        rc = get_compat_cmd(cmd, cmd32);
        if (rc)
                return rc;

        rc = translated_ioctl(file, COMEDI_CMDTEST, (unsigned long)cmd);
        if (rc < 0)
                return rc;

        err = put_compat_cmd(cmd32, cmd);
        if (err)
                rc = err;

        return rc;
}

/* Copy 32-bit insn structure to native insn structure. */
static int get_compat_insn(struct comedi_insn __user * insn,
                           struct comedi32_insn_struct __user * insn32)
{
        int err;
        union {
                unsigned int uint;
                compat_uptr_t uptr;
        } temp;

        /* Copy insn structure.  Ignore the unused members. */
        err = 0;
        if (!access_ok(VERIFY_READ, insn32, sizeof(*insn32))
            || !access_ok(VERIFY_WRITE, insn, sizeof(*insn)))
                return -EFAULT;

        err |= __get_user(temp.uint, &insn32->insn);
        err |= __put_user(temp.uint, &insn->insn);
        err |= __get_user(temp.uint, &insn32->n);
        err |= __put_user(temp.uint, &insn->n);
        err |= __get_user(temp.uptr, &insn32->data);
        err |= __put_user(compat_ptr(temp.uptr), &insn->data);
        err |= __get_user(temp.uint, &insn32->subdev);
        err |= __put_user(temp.uint, &insn->subdev);
        err |= __get_user(temp.uint, &insn32->chanspec);
        err |= __put_user(temp.uint, &insn->chanspec);
        return err ? -EFAULT : 0;
}

/* Handle 32-bit COMEDI_INSNLIST ioctl. */
static int compat_insnlist(struct file *file, unsigned long arg)
{
        struct combined_insnlist {
                struct comedi_insnlist insnlist;
                struct comedi_insn insn[1];
        } __user *s;
        struct comedi32_insnlist_struct __user *insnlist32;
        struct comedi32_insn_struct __user *insn32;
        compat_uptr_t uptr;
        unsigned int n_insns, n;
        int err, rc;

        insnlist32 = compat_ptr(arg);

        /* Get 32-bit insnlist structure.  */
        if (!access_ok(VERIFY_READ, insnlist32, sizeof(*insnlist32))) {
                return -EFAULT;
        }
        err = 0;
        err |= __get_user(n_insns, &insnlist32->n_insns);
        err |= __get_user(uptr, &insnlist32->insns);
        insn32 = compat_ptr(uptr);
        if (err)
                return -EFAULT;

        /* Allocate user memory to copy insnlist and insns into. */
        s = compat_alloc_user_space(offsetof(struct combined_insnlist,
                                             insn[n_insns]));

        /* Set native insnlist structure. */
        if (!access_ok(VERIFY_WRITE, &s->insnlist, sizeof(s->insnlist))) {
                return -EFAULT;
        }
        err |= __put_user(n_insns, &s->insnlist.n_insns);
        err |= __put_user(&s->insn[0], &s->insnlist.insns);
        if (err)
                return -EFAULT;

        /* Copy insn structures. */
        for (n = 0; n < n_insns; n++) {
                rc = get_compat_insn(&s->insn[n], &insn32[n]);
                if (rc)
                        return rc;
        }

        return translated_ioctl(file, COMEDI_INSNLIST,
                                (unsigned long)&s->insnlist);
}

/* Handle 32-bit COMEDI_INSN ioctl. */
static int compat_insn(struct file *file, unsigned long arg)
{
        struct comedi_insn __user *insn;
        struct comedi32_insn_struct __user *insn32;
        int rc;

        insn32 = compat_ptr(arg);
        insn = compat_alloc_user_space(sizeof(*insn));

        rc = get_compat_insn(insn, insn32);
        if (rc)
                return rc;

        return translated_ioctl(file, COMEDI_INSN, (unsigned long)insn);
}

/* Process untranslated ioctl. */
/* Returns -ENOIOCTLCMD for unrecognised ioctl codes. */
static inline int raw_ioctl(struct file *file, unsigned int cmd,
                            unsigned long arg)
{
        int rc;

        switch (cmd) {
        case COMEDI_DEVCONFIG:
        case COMEDI_DEVINFO:
        case COMEDI_SUBDINFO:
        case COMEDI_BUFCONFIG:
        case COMEDI_BUFINFO:
                /* Just need to translate the pointer argument. */
                arg = (unsigned long)compat_ptr(arg);
                rc = translated_ioctl(file, cmd, arg);
                break;
        case COMEDI_LOCK:
        case COMEDI_UNLOCK:
        case COMEDI_CANCEL:
        case COMEDI_POLL:
                /* No translation needed. */
                rc = translated_ioctl(file, cmd, arg);
                break;
        case COMEDI32_CHANINFO:
                rc = compat_chaninfo(file, arg);
                break;
        case COMEDI32_RANGEINFO:
                rc = compat_rangeinfo(file, arg);
                break;
        case COMEDI32_CMD:
                rc = compat_cmd(file, arg);
                break;
        case COMEDI32_CMDTEST:
                rc = compat_cmdtest(file, arg);
                break;
        case COMEDI32_INSNLIST:
                rc = compat_insnlist(file, arg);
                break;
        case COMEDI32_INSN:
                rc = compat_insn(file, arg);
                break;
        default:
                rc = -ENOIOCTLCMD;
                break;
        }
        return rc;
}

#ifdef HAVE_COMPAT_IOCTL        /* defined in <linux/fs.h> 2.6.11 onwards */

/* compat_ioctl file operation. */
/* Returns -ENOIOCTLCMD for unrecognised ioctl codes. */
long comedi_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
        return raw_ioctl(file, cmd, arg);
}

#else /* HAVE_COMPAT_IOCTL */

/*
 * Brain-dead ioctl compatibility for 2.6.10 and earlier.
 *
 * It's brain-dead because cmd numbers need to be unique system-wide!
 * The comedi driver could end up attempting to execute ioctls for non-Comedi
 * devices because it registered the system-wide cmd code first.  Similarly,
 * another driver could end up attempting to execute ioctls for a Comedi
 * device because it registered the cmd code first.  Chaos ensues.
 */

/* Handler for all 32-bit ioctl codes registered by this driver. */
static int mapped_ioctl(unsigned int fd, unsigned int cmd, unsigned long arg,
                        struct file *file)
{
        int rc;

        /* Make sure we are dealing with a Comedi device. */
        if (imajor(file->f_dentry->d_inode) != COMEDI_MAJOR)
                return -ENOTTY;

        rc = raw_ioctl(file, cmd, arg);
        /* Do not return -ENOIOCTLCMD. */
        if (rc == -ENOIOCTLCMD)
                rc = -ENOTTY;

        return rc;
}

struct ioctl32_map {
        unsigned int cmd;
        int (*handler) (unsigned int, unsigned int, unsigned long,
                        struct file *);
        int registered;
};

static struct ioctl32_map comedi_ioctl32_map[] = {
        {COMEDI_DEVCONFIG, mapped_ioctl, 0},
        {COMEDI_DEVINFO, mapped_ioctl, 0},
        {COMEDI_SUBDINFO, mapped_ioctl, 0},
        {COMEDI_BUFCONFIG, mapped_ioctl, 0},
        {COMEDI_BUFINFO, mapped_ioctl, 0},
        {COMEDI_LOCK, mapped_ioctl, 0},
        {COMEDI_UNLOCK, mapped_ioctl, 0},
        {COMEDI_CANCEL, mapped_ioctl, 0},
        {COMEDI_POLL, mapped_ioctl, 0},
        {COMEDI32_CHANINFO, mapped_ioctl, 0},
        {COMEDI32_RANGEINFO, mapped_ioctl, 0},
        {COMEDI32_CMD, mapped_ioctl, 0},
        {COMEDI32_CMDTEST, mapped_ioctl, 0},
        {COMEDI32_INSNLIST, mapped_ioctl, 0},
        {COMEDI32_INSN, mapped_ioctl, 0},
};

#define NUM_IOCTL32_MAPS ARRAY_SIZE(comedi_ioctl32_map)

/* Register system-wide 32-bit ioctl handlers. */
void comedi_register_ioctl32(void)
{
        int n, rc;

        for (n = 0; n < NUM_IOCTL32_MAPS; n++) {
                rc = register_ioctl32_conversion(comedi_ioctl32_map[n].cmd,
                                                 comedi_ioctl32_map[n].handler);
                if (rc) {
                        printk(KERN_WARNING
                               "comedi: failed to register 32-bit "
                               "compatible ioctl handler for 0x%X - "
                               "expect bad things to happen!\n",
                               comedi_ioctl32_map[n].cmd);
                }
                comedi_ioctl32_map[n].registered = !rc;
        }
}

/* Unregister system-wide 32-bit ioctl translations. */
void comedi_unregister_ioctl32(void)
{
        int n, rc;

        for (n = 0; n < NUM_IOCTL32_MAPS; n++) {
                if (comedi_ioctl32_map[n].registered) {
                        rc = unregister_ioctl32_conversion(comedi_ioctl32_map
                                                           [n].cmd,
                                                           comedi_ioctl32_map
                                                           [n].handler);
                        if (rc) {
                                printk(KERN_ERR
                                       "comedi: failed to unregister 32-bit "
                                       "compatible ioctl handler for 0x%X - "
                                       "expect kernel Oops!\n",
                                       comedi_ioctl32_map[n].cmd);
                        } else {
                                comedi_ioctl32_map[n].registered = 0;
                        }
                }
        }
}

#endif /* HAVE_COMPAT_IOCTL */

#endif /* CONFIG_COMPAT */