uinput.c

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/*
 *  User level driver support for input subsystem
 *
 * Heavily based on evdev.c by Vojtech Pavlik
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Author: Aristeu Sergio Rozanski Filho <[email protected]>
 *
 * Changes/Revisions:
 *  0.3 09/04/2006 (Anssi Hannula <[email protected]>)
 *      - updated ff support for the changes in kernel interface
 *      - added MODULE_VERSION
 *  0.2 16/10/2004 (Micah Dowty <[email protected]>)
 *      - added force feedback support
 *              - added UI_SET_PHYS
 *  0.1 20/06/2002
 *      - first public version
 */
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/uinput.h>
#include <linux/input/mt.h>
#include "../input-compat.h"

static int uinput_dev_event(struct input_dev *dev,
                unsigned int type, unsigned int code, int value)
{
    struct uinput_device    *udev = input_get_drvdata(dev);

    udev->buff[udev->head].type = type;
    udev->buff[udev->head].code = code;
    udev->buff[udev->head].value = value;
    do_gettimeofday(&udev->buff[udev->head].time);
    udev->head = (udev->head + 1) % UINPUT_BUFFER_SIZE;

    wake_up_interruptible(&udev->waitq);

    return 0;
}

/* Atomically allocate an ID for the given request. Returns 0 on success. */
static bool uinput_request_alloc_id(struct uinput_device *udev,
                    struct uinput_request *request)
{
    unsigned int id;
    bool reserved = false;

    spin_lock(&udev->requests_lock);

    for (id = 0; id < UINPUT_NUM_REQUESTS; id++) {
        if (!udev->requests[id]) {
            request->id = id;
            udev->requests[id] = request;
            reserved = true;
            break;
        }
    }

    spin_unlock(&udev->requests_lock);
    return reserved;
}

static struct uinput_request *uinput_request_find(struct uinput_device *udev,
                          unsigned int id)
{
    /* Find an input request, by ID. Returns NULL if the ID isn't valid. */
    if (id >= UINPUT_NUM_REQUESTS)
        return NULL;

    return udev->requests[id];
}

static int uinput_request_reserve_slot(struct uinput_device *udev,
                       struct uinput_request *request)
{
    /* Allocate slot. If none are available right away, wait. */
    return wait_event_interruptible(udev->requests_waitq,
                    uinput_request_alloc_id(udev, request));
}

static void uinput_request_done(struct uinput_device *udev,
                struct uinput_request *request)
{
    /* Mark slot as available */
    udev->requests[request->id] = NULL;
    wake_up(&udev->requests_waitq);

    complete(&request->done);
}

static int uinput_request_send(struct uinput_device *udev,
                   struct uinput_request *request)
{
    int retval;

    retval = mutex_lock_interruptible(&udev->mutex);
    if (retval)
        return retval;

    if (udev->state != UIST_CREATED) {
        retval = -ENODEV;
        goto out;
    }

    init_completion(&request->done);

    /*
     * Tell our userspace application about this new request
     * by queueing an input event.
     */
    uinput_dev_event(udev->dev, EV_UINPUT, request->code, request->id);

 out:
    mutex_unlock(&udev->mutex);
    return retval;
}

static int uinput_request_submit(struct uinput_device *udev,
                 struct uinput_request *request)
{
    int error;

    error = uinput_request_reserve_slot(udev, request);
    if (error)
        return error;

    error = uinput_request_send(udev, request);
    if (error) {
        uinput_request_done(udev, request);
        return error;
    }

    wait_for_completion(&request->done);
    return request->retval;
}

/*
 * Fail all outstanding requests so handlers don't wait for the userspace
 * to finish processing them.
 */
static void uinput_flush_requests(struct uinput_device *udev)
{
    struct uinput_request *request;
    int i;

    spin_lock(&udev->requests_lock);

    for (i = 0; i < UINPUT_NUM_REQUESTS; i++) {
        request = udev->requests[i];
        if (request) {
            request->retval = -ENODEV;
            uinput_request_done(udev, request);
        }
    }

    spin_unlock(&udev->requests_lock);
}

static void uinput_dev_set_gain(struct input_dev *dev, u16 gain)
{
    uinput_dev_event(dev, EV_FF, FF_GAIN, gain);
}

static void uinput_dev_set_autocenter(struct input_dev *dev, u16 magnitude)
{
    uinput_dev_event(dev, EV_FF, FF_AUTOCENTER, magnitude);
}

static int uinput_dev_playback(struct input_dev *dev, int effect_id, int value)
{
    return uinput_dev_event(dev, EV_FF, effect_id, value);
}

static int uinput_dev_upload_effect(struct input_dev *dev,
                    struct ff_effect *effect,
                    struct ff_effect *old)
{
    struct uinput_device *udev = input_get_drvdata(dev);
    struct uinput_request request;

    /*
     * uinput driver does not currently support periodic effects with
     * custom waveform since it does not have a way to pass buffer of
     * samples (custom_data) to userspace. If ever there is a device
     * supporting custom waveforms we would need to define an additional
     * ioctl (UI_UPLOAD_SAMPLES) but for now we just bail out.
     */
    if (effect->type == FF_PERIODIC &&
            effect->u.periodic.waveform == FF_CUSTOM)
        return -EINVAL;

    request.code = UI_FF_UPLOAD;
    request.u.upload.effect = effect;
    request.u.upload.old = old;

    return uinput_request_submit(udev, &request);
}

static int uinput_dev_erase_effect(struct input_dev *dev, int effect_id)
{
    struct uinput_device *udev = input_get_drvdata(dev);
    struct uinput_request request;

    if (!test_bit(EV_FF, dev->evbit))
        return -ENOSYS;

    request.code = UI_FF_ERASE;
    request.u.effect_id = effect_id;

    return uinput_request_submit(udev, &request);
}

static void uinput_destroy_device(struct uinput_device *udev)
{
    const char *name, *phys;
    struct input_dev *dev = udev->dev;
    enum uinput_state old_state = udev->state;

    udev->state = UIST_NEW_DEVICE;

    if (dev) {
        name = dev->name;
        phys = dev->phys;
        if (old_state == UIST_CREATED) {
            uinput_flush_requests(udev);
            input_unregister_device(dev);
        } else {
            input_free_device(dev);
        }
        kfree(name);
        kfree(phys);
        udev->dev = NULL;
    }
}

static int uinput_create_device(struct uinput_device *udev)
{
    struct input_dev *dev = udev->dev;
    int error;

    if (udev->state != UIST_SETUP_COMPLETE) {
        printk(KERN_DEBUG "%s: write device info first\n", UINPUT_NAME);
        return -EINVAL;
    }

    if (udev->ff_effects_max) {
        error = input_ff_create(dev, udev->ff_effects_max);
        if (error)
            goto fail1;

        dev->ff->upload = uinput_dev_upload_effect;
        dev->ff->erase = uinput_dev_erase_effect;
        dev->ff->playback = uinput_dev_playback;
        dev->ff->set_gain = uinput_dev_set_gain;
        dev->ff->set_autocenter = uinput_dev_set_autocenter;
    }

    error = input_register_device(udev->dev);
    if (error)
        goto fail2;

    udev->state = UIST_CREATED;

    return 0;

 fail2: input_ff_destroy(dev);
 fail1: uinput_destroy_device(udev);
    return error;
}

static int uinput_open(struct inode *inode, struct file *file)
{
    struct uinput_device *newdev;

    newdev = kzalloc(sizeof(struct uinput_device), GFP_KERNEL);
    if (!newdev)
        return -ENOMEM;

    mutex_init(&newdev->mutex);
    spin_lock_init(&newdev->requests_lock);
    init_waitqueue_head(&newdev->requests_waitq);
    init_waitqueue_head(&newdev->waitq);
    newdev->state = UIST_NEW_DEVICE;

    file->private_data = newdev;
    nonseekable_open(inode, file);

    return 0;
}

static int uinput_validate_absbits(struct input_dev *dev)
{
    unsigned int cnt;
    int retval = 0;

    for (cnt = 0; cnt < ABS_CNT; cnt++) {
        int min, max;
        if (!test_bit(cnt, dev->absbit))
            continue;

        min = input_abs_get_min(dev, cnt);
        max = input_abs_get_max(dev, cnt);

        if ((min != 0 || max != 0) && max <= min) {
            printk(KERN_DEBUG
                "%s: invalid abs[%02x] min:%d max:%d\n",
                UINPUT_NAME, cnt,
                input_abs_get_min(dev, cnt),
                input_abs_get_max(dev, cnt));
            retval = -EINVAL;
            break;
        }

        if (input_abs_get_flat(dev, cnt) >
            input_abs_get_max(dev, cnt) - input_abs_get_min(dev, cnt)) {
            printk(KERN_DEBUG
                "%s: abs_flat #%02x out of range: %d "
                "(min:%d/max:%d)\n",
                UINPUT_NAME, cnt,
                input_abs_get_flat(dev, cnt),
                input_abs_get_min(dev, cnt),
                input_abs_get_max(dev, cnt));
            retval = -EINVAL;
            break;
        }
    }
    return retval;
}

static int uinput_allocate_device(struct uinput_device *udev)
{
    udev->dev = input_allocate_device();
    if (!udev->dev)
        return -ENOMEM;

    udev->dev->event = uinput_dev_event;
    input_set_drvdata(udev->dev, udev);

    return 0;
}

static int uinput_setup_device(struct uinput_device *udev,
                   const char __user *buffer, size_t count)
{
    struct uinput_user_dev  *user_dev;
    struct input_dev    *dev;
    int         i;
    int         retval;

    if (count != sizeof(struct uinput_user_dev))
        return -EINVAL;

    if (!udev->dev) {
        retval = uinput_allocate_device(udev);
        if (retval)
            return retval;
    }

    dev = udev->dev;

    user_dev = memdup_user(buffer, sizeof(struct uinput_user_dev));
    if (IS_ERR(user_dev))
        return PTR_ERR(user_dev);

    udev->ff_effects_max = user_dev->ff_effects_max;

    /* Ensure name is filled in */
    if (!user_dev->name[0]) {
        retval = -EINVAL;
        goto exit;
    }

    kfree(dev->name);
    dev->name = kstrndup(user_dev->name, UINPUT_MAX_NAME_SIZE,
                 GFP_KERNEL);
    if (!dev->name) {
        retval = -ENOMEM;
        goto exit;
    }

    dev->id.bustype = user_dev->id.bustype;
    dev->id.vendor  = user_dev->id.vendor;
    dev->id.product = user_dev->id.product;
    dev->id.version = user_dev->id.version;

    for (i = 0; i < ABS_CNT; i++) {
        input_abs_set_max(dev, i, user_dev->absmax[i]);
        input_abs_set_min(dev, i, user_dev->absmin[i]);
        input_abs_set_fuzz(dev, i, user_dev->absfuzz[i]);
        input_abs_set_flat(dev, i, user_dev->absflat[i]);
    }

    /* check if absmin/absmax/absfuzz/absflat are filled as
     * told in Documentation/input/input-programming.txt */
    if (test_bit(EV_ABS, dev->evbit)) {
        retval = uinput_validate_absbits(dev);
        if (retval < 0)
            goto exit;
        if (test_bit(ABS_MT_SLOT, dev->absbit)) {
            int nslot = input_abs_get_max(dev, ABS_MT_SLOT) + 1;
            input_mt_init_slots(dev, nslot, 0);
        } else if (test_bit(ABS_MT_POSITION_X, dev->absbit)) {
            input_set_events_per_packet(dev, 60);
        }
    }

    udev->state = UIST_SETUP_COMPLETE;
    retval = count;

 exit:
    kfree(user_dev);
    return retval;
}

static ssize_t uinput_inject_event(struct uinput_device *udev,
                   const char __user *buffer, size_t count)
{
    struct input_event ev;

    if (count < input_event_size())
        return -EINVAL;

    if (input_event_from_user(buffer, &ev))
        return -EFAULT;

    input_event(udev->dev, ev.type, ev.code, ev.value);

    return input_event_size();
}

static ssize_t uinput_write(struct file *file, const char __user *buffer,
                size_t count, loff_t *ppos)
{
    struct uinput_device *udev = file->private_data;
    int retval;

    if (count == 0)
        return 0;

    retval = mutex_lock_interruptible(&udev->mutex);
    if (retval)
        return retval;

    retval = udev->state == UIST_CREATED ?
            uinput_inject_event(udev, buffer, count) :
            uinput_setup_device(udev, buffer, count);

    mutex_unlock(&udev->mutex);

    return retval;
}

static bool uinput_fetch_next_event(struct uinput_device *udev,
                    struct input_event *event)
{
    bool have_event;

    spin_lock_irq(&udev->dev->event_lock);

    have_event = udev->head != udev->tail;
    if (have_event) {
        *event = udev->buff[udev->tail];
        udev->tail = (udev->tail + 1) % UINPUT_BUFFER_SIZE;
    }

    spin_unlock_irq(&udev->dev->event_lock);

    return have_event;
}

static ssize_t uinput_events_to_user(struct uinput_device *udev,
                     char __user *buffer, size_t count)
{
    struct input_event event;
    size_t read = 0;

    while (read + input_event_size() <= count &&
           uinput_fetch_next_event(udev, &event)) {

        if (input_event_to_user(buffer + read, &event))
            return -EFAULT;

        read += input_event_size();
    }

    return read;
}

static ssize_t uinput_read(struct file *file, char __user *buffer,
               size_t count, loff_t *ppos)
{
    struct uinput_device *udev = file->private_data;
    ssize_t retval;

    if (count != 0 && count < input_event_size())
        return -EINVAL;

    do {
        retval = mutex_lock_interruptible(&udev->mutex);
        if (retval)
            return retval;

        if (udev->state != UIST_CREATED)
            retval = -ENODEV;
        else if (udev->head == udev->tail &&
             (file->f_flags & O_NONBLOCK))
            retval = -EAGAIN;
        else
            retval = uinput_events_to_user(udev, buffer, count);

        mutex_unlock(&udev->mutex);

        if (retval || count == 0)
            break;

        if (!(file->f_flags & O_NONBLOCK))
            retval = wait_event_interruptible(udev->waitq,
                          udev->head != udev->tail ||
                          udev->state != UIST_CREATED);
    } while (retval == 0);

    return retval;
}

static unsigned int uinput_poll(struct file *file, poll_table *wait)
{
    struct uinput_device *udev = file->private_data;

    poll_wait(file, &udev->waitq, wait);

    if (udev->head != udev->tail)
        return POLLIN | POLLRDNORM;

    return 0;
}

static int uinput_release(struct inode *inode, struct file *file)
{
    struct uinput_device *udev = file->private_data;

    uinput_destroy_device(udev);
    kfree(udev);

    return 0;
}

#ifdef CONFIG_COMPAT
struct uinput_ff_upload_compat {
    __u32           request_id;
    __s32           retval;
    struct ff_effect_compat effect;
    struct ff_effect_compat old;
};

static int uinput_ff_upload_to_user(char __user *buffer,
                    const struct uinput_ff_upload *ff_up)
{
    if (INPUT_COMPAT_TEST) {
        struct uinput_ff_upload_compat ff_up_compat;

        ff_up_compat.request_id = ff_up->request_id;
        ff_up_compat.retval = ff_up->retval;
        /*
         * It so happens that the pointer that gives us the trouble
         * is the last field in the structure. Since we don't support
         * custom waveforms in uinput anyway we can just copy the whole
         * thing (to the compat size) and ignore the pointer.
         */
        memcpy(&ff_up_compat.effect, &ff_up->effect,
            sizeof(struct ff_effect_compat));
        memcpy(&ff_up_compat.old, &ff_up->old,
            sizeof(struct ff_effect_compat));

        if (copy_to_user(buffer, &ff_up_compat,
                 sizeof(struct uinput_ff_upload_compat)))
            return -EFAULT;
    } else {
        if (copy_to_user(buffer, ff_up,
                 sizeof(struct uinput_ff_upload)))
            return -EFAULT;
    }

    return 0;
}

static int uinput_ff_upload_from_user(const char __user *buffer,
                      struct uinput_ff_upload *ff_up)
{
    if (INPUT_COMPAT_TEST) {
        struct uinput_ff_upload_compat ff_up_compat;

        if (copy_from_user(&ff_up_compat, buffer,
                   sizeof(struct uinput_ff_upload_compat)))
            return -EFAULT;

        ff_up->request_id = ff_up_compat.request_id;
        ff_up->retval = ff_up_compat.retval;
        memcpy(&ff_up->effect, &ff_up_compat.effect,
            sizeof(struct ff_effect_compat));
        memcpy(&ff_up->old, &ff_up_compat.old,
            sizeof(struct ff_effect_compat));

    } else {
        if (copy_from_user(ff_up, buffer,
                   sizeof(struct uinput_ff_upload)))
            return -EFAULT;
    }

    return 0;
}

#else

static int uinput_ff_upload_to_user(char __user *buffer,
                    const struct uinput_ff_upload *ff_up)
{
    if (copy_to_user(buffer, ff_up, sizeof(struct uinput_ff_upload)))
        return -EFAULT;

    return 0;
}

static int uinput_ff_upload_from_user(const char __user *buffer,
                      struct uinput_ff_upload *ff_up)
{
    if (copy_from_user(ff_up, buffer, sizeof(struct uinput_ff_upload)))
        return -EFAULT;

    return 0;
}

#endif

#define uinput_set_bit(_arg, _bit, _max)        \
({                          \
    int __ret = 0;                  \
    if (udev->state == UIST_CREATED)        \
        __ret =  -EINVAL;           \
    else if ((_arg) > (_max))           \
        __ret = -EINVAL;            \
    else set_bit((_arg), udev->dev->_bit);      \
    __ret;                      \
})

static long uinput_ioctl_handler(struct file *file, unsigned int cmd,
                 unsigned long arg, void __user *p)
{
    int         retval;
    struct uinput_device    *udev = file->private_data;
    struct uinput_ff_upload ff_up;
    struct uinput_ff_erase  ff_erase;
    struct uinput_request   *req;
    char            *phys;

    retval = mutex_lock_interruptible(&udev->mutex);
    if (retval)
        return retval;

    if (!udev->dev) {
        retval = uinput_allocate_device(udev);
        if (retval)
            goto out;
    }

    switch (cmd) {
        case UI_DEV_CREATE:
            retval = uinput_create_device(udev);
            break;

        case UI_DEV_DESTROY:
            uinput_destroy_device(udev);
            break;

        case UI_SET_EVBIT:
            retval = uinput_set_bit(arg, evbit, EV_MAX);
            break;

        case UI_SET_KEYBIT:
            retval = uinput_set_bit(arg, keybit, KEY_MAX);
            break;

        case UI_SET_RELBIT:
            retval = uinput_set_bit(arg, relbit, REL_MAX);
            break;

        case UI_SET_ABSBIT:
            retval = uinput_set_bit(arg, absbit, ABS_MAX);
            break;

        case UI_SET_MSCBIT:
            retval = uinput_set_bit(arg, mscbit, MSC_MAX);
            break;

        case UI_SET_LEDBIT:
            retval = uinput_set_bit(arg, ledbit, LED_MAX);
            break;

        case UI_SET_SNDBIT:
            retval = uinput_set_bit(arg, sndbit, SND_MAX);
            break;

        case UI_SET_FFBIT:
            retval = uinput_set_bit(arg, ffbit, FF_MAX);
            break;

        case UI_SET_SWBIT:
            retval = uinput_set_bit(arg, swbit, SW_MAX);
            break;

        case UI_SET_PROPBIT:
            retval = uinput_set_bit(arg, propbit, INPUT_PROP_MAX);
            break;

        case UI_SET_PHYS:
            if (udev->state == UIST_CREATED) {
                retval = -EINVAL;
                goto out;
            }

            phys = strndup_user(p, 1024);
            if (IS_ERR(phys)) {
                retval = PTR_ERR(phys);
                goto out;
            }

            kfree(udev->dev->phys);
            udev->dev->phys = phys;
            break;

        case UI_BEGIN_FF_UPLOAD:
            retval = uinput_ff_upload_from_user(p, &ff_up);
            if (retval)
                break;

            req = uinput_request_find(udev, ff_up.request_id);
            if (!req || req->code != UI_FF_UPLOAD ||
                !req->u.upload.effect) {
                retval = -EINVAL;
                break;
            }

            ff_up.retval = 0;
            ff_up.effect = *req->u.upload.effect;
            if (req->u.upload.old)
                ff_up.old = *req->u.upload.old;
            else
                memset(&ff_up.old, 0, sizeof(struct ff_effect));

            retval = uinput_ff_upload_to_user(p, &ff_up);
            break;

        case UI_BEGIN_FF_ERASE:
            if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
                retval = -EFAULT;
                break;
            }

            req = uinput_request_find(udev, ff_erase.request_id);
            if (!req || req->code != UI_FF_ERASE) {
                retval = -EINVAL;
                break;
            }

            ff_erase.retval = 0;
            ff_erase.effect_id = req->u.effect_id;
            if (copy_to_user(p, &ff_erase, sizeof(ff_erase))) {
                retval = -EFAULT;
                break;
            }

            break;

        case UI_END_FF_UPLOAD:
            retval = uinput_ff_upload_from_user(p, &ff_up);
            if (retval)
                break;

            req = uinput_request_find(udev, ff_up.request_id);
            if (!req || req->code != UI_FF_UPLOAD ||
                !req->u.upload.effect) {
                retval = -EINVAL;
                break;
            }

            req->retval = ff_up.retval;
            uinput_request_done(udev, req);
            break;

        case UI_END_FF_ERASE:
            if (copy_from_user(&ff_erase, p, sizeof(ff_erase))) {
                retval = -EFAULT;
                break;
            }

            req = uinput_request_find(udev, ff_erase.request_id);
            if (!req || req->code != UI_FF_ERASE) {
                retval = -EINVAL;
                break;
            }

            req->retval = ff_erase.retval;
            uinput_request_done(udev, req);
            break;

        default:
            retval = -EINVAL;
    }

 out:
    mutex_unlock(&udev->mutex);
    return retval;
}

static long uinput_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
    return uinput_ioctl_handler(file, cmd, arg, (void __user *)arg);
}

#ifdef CONFIG_COMPAT
static long uinput_compat_ioctl(struct file *file,
                unsigned int cmd, unsigned long arg)
{
    return uinput_ioctl_handler(file, cmd, arg, compat_ptr(arg));
}
#endif

static const struct file_operations uinput_fops = {
    .owner      = THIS_MODULE,
    .open       = uinput_open,
    .release    = uinput_release,
    .read       = uinput_read,
    .write      = uinput_write,
    .poll       = uinput_poll,
    .unlocked_ioctl = uinput_ioctl,
#ifdef CONFIG_COMPAT
    .compat_ioctl   = uinput_compat_ioctl,
#endif
    .llseek     = no_llseek,
};

static struct miscdevice uinput_misc = {
    .fops       = &uinput_fops,
    .minor      = UINPUT_MINOR,
    .name       = UINPUT_NAME,
};
MODULE_ALIAS_MISCDEV(UINPUT_MINOR);
MODULE_ALIAS("devname:" UINPUT_NAME);

static int __init uinput_init(void)
{
    return misc_register(&uinput_misc);
}

static void __exit uinput_exit(void)
{
    misc_deregister(&uinput_misc);
}

MODULE_AUTHOR("Aristeu Sergio Rozanski Filho");
MODULE_DESCRIPTION("User level driver support for input subsystem");
MODULE_LICENSE("GPL");
MODULE_VERSION("0.3");

module_init(uinput_init);
module_exit(uinput_exit);