ClabureDB: Classified Bug-Reports Database

  /*
   * HID raw devices, giving access to raw HID events.
   *
   * In comparison to hiddev, this device does not process the
   * hid events at all (no parsing, no lookups). This lets applications
   * to work on raw hid events as they want to, and avoids a need to
   * use a transport-specific userspace libhid/libusb libraries.
   *
   *  Copyright (c) 2007 Jiri Kosina
  */
 
 /*
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
  *
  * 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.,
  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #include <linux/fs.h>
 #include <linux/module.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/cdev.h>
 #include <linux/poll.h>
 #include <linux/device.h>
 #include <linux/major.h>
 #include <linux/hid.h>
 #include <linux/mutex.h>
 #include <linux/smp_lock.h>
 
 #include <linux/hidraw.h>
 
 static int hidraw_major;
 static struct cdev hidraw_cdev;
 static struct class *hidraw_class;
 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
 static DEFINE_MUTEX(minors_lock);
 
 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
 {
         struct hidraw_list *list = file->private_data;
         int ret = 0, len;
         char *report;
         DECLARE_WAITQUEUE(wait, current);
 
         while (ret == 0) {
 
                 mutex_lock(&list->read_mutex);
 
                 if (list->head == list->tail) {
                         add_wait_queue(&list->hidraw->wait, &wait);
                         set_current_state(TASK_INTERRUPTIBLE);
 
                         while (list->head == list->tail) {
                                 if (file->f_flags & O_NONBLOCK) {
                                         ret = -EAGAIN;
                                         break;
                                 }
                                 if (signal_pending(current)) {
                                         ret = -ERESTARTSYS;
                                         break;
                                 }
                                 if (!list->hidraw->exist) {
                                         ret = -EIO;
                                         break;
                                 }
 
                                 /* allow O_NONBLOCK to work well from other threads */
                                 mutex_unlock(&list->read_mutex);
                                 schedule();
                                 mutex_lock(&list->read_mutex);
                                 set_current_state(TASK_INTERRUPTIBLE);
                         }
 
                         set_current_state(TASK_RUNNING);
                         remove_wait_queue(&list->hidraw->wait, &wait);
                 }
 
                 if (ret)
                         goto out;
 
                 report = list->buffer[list->tail].value;
                 len = list->buffer[list->tail].len > count ?
                         count : list->buffer[list->tail].len;
 
                 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
                         ret = -EFAULT;
                         goto out;
                 }
                 ret += len;
 
                 kfree(list->buffer[list->tail].value);
                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
         }
 out:
        mutex_unlock(&list->read_mutex);
        return ret;
}

/* the first byte is expected to be a report number */
static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
        unsigned int minor = iminor(file->f_path.dentry->d_inode);
        /* FIXME: What stops hidraw_table going NULL */
        struct hid_device *dev = hidraw_table[minor]->hid;
        __u8 *buf;
        int ret = 0;

        if (!dev->hid_output_raw_report)
                return -ENODEV;

        if (count > HID_MAX_BUFFER_SIZE) {
                printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
                                task_pid_nr(current));
                return -EINVAL;
        }

        if (count < 2) {
                printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
                                task_pid_nr(current));
                return -EINVAL;
        }

        buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        if (copy_from_user(buf, buffer, count)) {
                ret = -EFAULT;
                goto out;
        }

        ret = dev->hid_output_raw_report(dev, buf, count);
out:
        kfree(buf);
        return ret;
}

static unsigned int hidraw_poll(struct file *file, poll_table *wait)
{
        struct hidraw_list *list = file->private_data;

        poll_wait(file, &list->hidraw->wait, wait);
        if (list->head != list->tail)
                return POLLIN | POLLRDNORM;
        if (!list->hidraw->exist)
                return POLLERR | POLLHUP;
        return 0;
}

static int hidraw_open(struct inode *inode, struct file *file)
{
        unsigned int minor = iminor(inode);
        struct hidraw *dev;
        struct hidraw_list *list;
        int err = 0;

        if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
                err = -ENOMEM;
                goto out;
        }

        lock_kernel();
        mutex_lock(&minors_lock);
        if (!hidraw_table[minor]) {
                printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
                                minor);
                kfree(list);
                err = -ENODEV;
                goto out_unlock;
        }

        list->hidraw = hidraw_table[minor];
        mutex_init(&list->read_mutex);
        list_add_tail(&list->node, &hidraw_table[minor]->list);
        file->private_data = list;

        dev = hidraw_table[minor];
        if (!dev->open++) {
                err = dev->hid->ll_driver->open(dev->hid);
                if (err < 0)
                        dev->open--;
        }

out_unlock:
        mutex_unlock(&minors_lock);
        unlock_kernel();
out:
        return err;

}

static int hidraw_release(struct inode * inode, struct file * file)
{
        unsigned int minor = iminor(inode);
        struct hidraw *dev;
        struct hidraw_list *list = file->private_data;

        if (!hidraw_table[minor]) {
                printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
                                minor);
                return -ENODEV;
        }

        list_del(&list->node);
        dev = hidraw_table[minor];
        if (!dev->open--) {
                if (list->hidraw->exist)
                        dev->hid->ll_driver->close(dev->hid);
                else
                        kfree(list->hidraw);
        }

        kfree(list);

        return 0;
}

static long hidraw_ioctl(struct file *file, unsigned int cmd,
                                                        unsigned long arg)
{
        struct inode *inode = file->f_path.dentry->d_inode;
        unsigned int minor = iminor(inode);
        long ret = 0;
        /* FIXME: What stops hidraw_table going NULL */
        struct hidraw *dev = hidraw_table[minor];
        void __user *user_arg = (void __user*) arg;

        lock_kernel();
        switch (cmd) {
                case HIDIOCGRDESCSIZE:
                        if (put_user(dev->hid->rsize, (int __user *)arg))
                                ret = -EFAULT;
                        break;

                case HIDIOCGRDESC:
                        {
                                __u32 len;

                                if (get_user(len, (int __user *)arg))
                                        ret = -EFAULT;
                                else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
                                        ret = -EINVAL;
                                else if (copy_to_user(user_arg + offsetof(
                                        struct hidraw_report_descriptor,
                                        value[0]),
                                        dev->hid->rdesc,
                                        min(dev->hid->rsize, len)))
                                        ret = -EFAULT;
                                break;
                        }
                case HIDIOCGRAWINFO:
                        {
                                struct hidraw_devinfo dinfo;

                                dinfo.bustype = dev->hid->bus;
                                dinfo.vendor = dev->hid->vendor;
                                dinfo.product = dev->hid->product;
                                if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
                                        ret = -EFAULT;
                                break;
                        }
                default:
                        ret = -ENOTTY;
        }
        unlock_kernel();
        return ret;
}

static const struct file_operations hidraw_ops = {
        .owner =        THIS_MODULE,
        .read =         hidraw_read,
        .write =        hidraw_write,
        .poll =         hidraw_poll,
        .open =         hidraw_open,
        .release =      hidraw_release,
        .unlocked_ioctl = hidraw_ioctl,
};

void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
{
        struct hidraw *dev = hid->hidraw;
        struct hidraw_list *list;

        list_for_each_entry(list, &dev->list, node) {
                list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
                list->buffer[list->head].len = len;
                list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
                kill_fasync(&list->fasync, SIGIO, POLL_IN);
        }

        wake_up_interruptible(&dev->wait);
}
EXPORT_SYMBOL_GPL(hidraw_report_event);

int hidraw_connect(struct hid_device *hid)
{
        int minor, result;
        struct hidraw *dev;

        /* TODO currently we accept any HID device. This should later
         * probably be fixed to accept only those devices which provide
         * non-input applications
         */

        dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
        if (!dev)
                return -ENOMEM;

        result = -EINVAL;

        mutex_lock(&minors_lock);

        for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
                if (hidraw_table[minor])
                        continue;
                hidraw_table[minor] = dev;
                result = 0;
                break;
        }

        if (result) {
                mutex_unlock(&minors_lock);
                kfree(dev);
                goto out;
        }

        dev->dev = device_create(hidraw_class, NULL, MKDEV(hidraw_major, minor),
                                 NULL, "%s%d", "hidraw", minor);

        if (IS_ERR(dev->dev)) {
                hidraw_table[minor] = NULL;
                mutex_unlock(&minors_lock);
                result = PTR_ERR(dev->dev);
                kfree(dev);
                goto out;
        }

        mutex_unlock(&minors_lock);
        init_waitqueue_head(&dev->wait);
        INIT_LIST_HEAD(&dev->list);

        dev->hid = hid;
        dev->minor = minor;

        dev->exist = 1;
        hid->hidraw = dev;

out:
        return result;

}
EXPORT_SYMBOL_GPL(hidraw_connect);

void hidraw_disconnect(struct hid_device *hid)
{
        struct hidraw *hidraw = hid->hidraw;

        hidraw->exist = 0;

        mutex_lock(&minors_lock);
        hidraw_table[hidraw->minor] = NULL;
        mutex_unlock(&minors_lock);

        device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));

        if (hidraw->open) {
                hid->ll_driver->close(hid);
                wake_up_interruptible(&hidraw->wait);
        } else {
                kfree(hidraw);
        }
}
EXPORT_SYMBOL_GPL(hidraw_disconnect);

int __init hidraw_init(void)
{
        int result;
        dev_t dev_id;

        result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
                        HIDRAW_MAX_DEVICES, "hidraw");

        hidraw_major = MAJOR(dev_id);

        if (result < 0) {
                printk(KERN_WARNING "hidraw: can't get major number\n");
                result = 0;
                goto out;
        }

        hidraw_class = class_create(THIS_MODULE, "hidraw");
        if (IS_ERR(hidraw_class)) {
                result = PTR_ERR(hidraw_class);
                unregister_chrdev(hidraw_major, "hidraw");
                goto out;
        }

        cdev_init(&hidraw_cdev, &hidraw_ops);
        cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
out:
        return result;
}

void hidraw_exit(void)
{
        dev_t dev_id = MKDEV(hidraw_major, 0);

        cdev_del(&hidraw_cdev);
        class_destroy(hidraw_class);
        unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);

}