drivers/hid/hidraw.c

   1 /*
   2  * HID raw devices, giving access to raw HID events.
   3  *
   4  * In comparison to hiddev, this device does not process the
   5  * hid events at all (no parsing, no lookups). This lets applications
   6  * to work on raw hid events as they want to, and avoids a need to
   7  * use a transport-specific userspace libhid/libusb libraries.
   8  *
   9  *  Copyright (c) 2007 Jiri Kosina
  10  */
  11
  12 /*
  13  * This program is free software; you can redistribute it and/or modify it
  14  * under the terms and conditions of the GNU General Public License,
  15  * version 2, as published by the Free Software Foundation.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  20  */
  21
  22 #include <linux/fs.h>
  23 #include <linux/module.h>
  24 #include <linux/errno.h>
  25 #include <linux/kernel.h>
  26 #include <linux/init.h>
  27 #include <linux/cdev.h>
  28 #include <linux/poll.h>
  29 #include <linux/device.h>
  30 #include <linux/major.h>
  31 #include <linux/hid.h>
  32 #include <linux/mutex.h>
  33 #include <linux/smp_lock.h>
  34
  35 #include <linux/hidraw.h>
  36
  37 static int hidraw_major;
  38 static struct cdev hidraw_cdev;
  39 static struct class *hidraw_class;
  40 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
  41 static DEFINE_MUTEX(minors_lock);
  42
  43 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
  44 {
  45         struct hidraw_list *list = file->private_data;
  46         int ret = 0, len;
  47         char *report;
  48         DECLARE_WAITQUEUE(wait, current);
  49
  50         while (ret == 0) {
  51
  52                 mutex_lock(&list->read_mutex);
  53
  54                 if (list->head == list->tail) {
  55                         add_wait_queue(&list->hidraw->wait, &wait);
  56                         set_current_state(TASK_INTERRUPTIBLE);
  57
  58                         while (list->head == list->tail) {
  59                                 if (file->f_flags & O_NONBLOCK) {
  60                                         ret = -EAGAIN;
  61                                         break;
  62                                 }
  63                                 if (signal_pending(current)) {
  64                                         ret = -ERESTARTSYS;
  65                                         break;
  66                                 }
  67                                 if (!list->hidraw->exist) {
  68                                         ret = -EIO;
  69                                         break;
  70                                 }
  71
  72                                 /* allow O_NONBLOCK to work well from other threads */
  73                                 mutex_unlock(&list->read_mutex);
  74                                 schedule();
  75                                 mutex_lock(&list->read_mutex);
  76                                 set_current_state(TASK_INTERRUPTIBLE);
  77                         }
  78
  79                         set_current_state(TASK_RUNNING);
  80                         remove_wait_queue(&list->hidraw->wait, &wait);
  81                 }
  82
  83                 if (ret)
  84                         goto out;
  85
  86                 report = list->buffer[list->tail].value;
  87                 len = list->buffer[list->tail].len > count ?
  88                         count : list->buffer[list->tail].len;
  89
  90                 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
  91                         ret = -EFAULT;
  92                         goto out;
  93                 }
  94                 ret += len;
  95
  96                 kfree(list->buffer[list->tail].value);
  97                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
  98         }
  99 out:
 100         mutex_unlock(&list->read_mutex);
 101         return ret;
 102 }
 103
 104 /* the first byte is expected to be a report number */
 105 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 106 {
 107         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 108         /* FIXME: What stops hidraw_table going NULL */
 109         struct hid_device *dev = hidraw_table[minor]->hid;
 110         __u8 *buf;
 111         int ret = 0;
 112
 113         if (!dev->hid_output_raw_report)
 114                 return -ENODEV;
 115
 116         if (count > HID_MAX_BUFFER_SIZE) {
 117                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 118                                 task_pid_nr(current));
 119                 return -EINVAL;
 120         }
 121
 122         if (count < 2) {
 123                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 124                                 task_pid_nr(current));
 125                 return -EINVAL;
 126         }
 127
 128         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 129         if (!buf)
 130                 return -ENOMEM;
 131
 132         if (copy_from_user(buf, buffer, count)) {
 133                 ret = -EFAULT;
 134                 goto out;
 135         }
 136
 137         ret = dev->hid_output_raw_report(dev, buf, count);
 138 out:
 139         kfree(buf);
 140         return ret;
 141 }
 142
 143 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 144 {
 145         struct hidraw_list *list = file->private_data;
 146
 147         poll_wait(file, &list->hidraw->wait, wait);
 148         if (list->head != list->tail)
 149                 return POLLIN | POLLRDNORM;
 150         if (!list->hidraw->exist)
 151                 return POLLERR | POLLHUP;
 152         return 0;
 153 }
 154
 155 static int hidraw_open(struct inode *inode, struct file *file)
 156 {
 157         unsigned int minor = iminor(inode);
 158         struct hidraw *dev;
 159         struct hidraw_list *list;
 160         int err = 0;
 161
 162         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 163                 err = -ENOMEM;
 164                 goto out;
 165         }
 166
 167         lock_kernel();
 168         mutex_lock(&minors_lock);
 169         if (!hidraw_table[minor]) {
 170                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 171                                 minor);
 172                 kfree(list);
 173                 err = -ENODEV;
 174                 goto out_unlock;
 175         }
 176
 177         list->hidraw = hidraw_table[minor];
 178         mutex_init(&list->read_mutex);
 179         list_add_tail(&list->node, &hidraw_table[minor]->list);
 180         file->private_data = list;
 181
 182         dev = hidraw_table[minor];
 183         if (!dev->open++) {
 184                 err = dev->hid->ll_driver->open(dev->hid);
 185                 if (err < 0)
 186                         dev->open--;
 187         }
 188
 189 out_unlock:
 190         mutex_unlock(&minors_lock);
 191         unlock_kernel();
 192 out:
 193         return err;
 194
 195 }
 196
 197 static int hidraw_release(struct inode * inode, struct file * file)
 198 {
 199         unsigned int minor = iminor(inode);
 200         struct hidraw *dev;
 201         struct hidraw_list *list = file->private_data;
 202
 203         if (!hidraw_table[minor]) {
 204                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 205                                 minor);
 206                 return -ENODEV;
 207         }
 208
 209         list_del(&list->node);
 210         dev = hidraw_table[minor];
 211         if (!dev->open--) {
 212                 if (list->hidraw->exist)
 213                         dev->hid->ll_driver->close(dev->hid);
 214                 else
 215                         kfree(list->hidraw);
 216         }
 217
 218         kfree(list);
 219
 220         return 0;
 221 }
 222
 223 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 224                                                         unsigned long arg)
 225 {
 226         struct inode *inode = file->f_path.dentry->d_inode;
 227         unsigned int minor = iminor(inode);
 228         long ret = 0;
 229         /* FIXME: What stops hidraw_table going NULL */
 230         struct hidraw *dev = hidraw_table[minor];
 231         void __user *user_arg = (void __user*) arg;
 232
 233         lock_kernel();
 234         switch (cmd) {
 235                 case HIDIOCGRDESCSIZE:
 236                         if (put_user(dev->hid->rsize, (int __user *)arg))
 237                                 ret = -EFAULT;
 238                         break;
 239
 240                 case HIDIOCGRDESC:
 241                         {
 242                                 __u32 len;
 243
 244                                 if (get_user(len, (int __user *)arg))
 245                                         ret = -EFAULT;
 246                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 247                                         ret = -EINVAL;
 248                                 else if (copy_to_user(user_arg + offsetof(
 249                                         struct hidraw_report_descriptor,
 250                                         value[0]),
 251                                         dev->hid->rdesc,
 252                                         min(dev->hid->rsize, len)))
 253                                         ret = -EFAULT;
 254                                 break;
 255                         }
 256                 case HIDIOCGRAWINFO:
 257                         {
 258                                 struct hidraw_devinfo dinfo;
 259
 260                                 dinfo.bustype = dev->hid->bus;
 261                                 dinfo.vendor = dev->hid->vendor;
 262                                 dinfo.product = dev->hid->product;
 263                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 264                                         ret = -EFAULT;
 265                                 break;
 266                         }
 267                 default:
 268                         ret = -ENOTTY;
 269         }
 270         unlock_kernel();
 271         return ret;
 272 }
 273
 274 static const struct file_operations hidraw_ops = {
 275         .owner =        THIS_MODULE,
 276         .read =         hidraw_read,
 277         .write =        hidraw_write,
 278         .poll =         hidraw_poll,
 279         .open =         hidraw_open,
 280         .release =      hidraw_release,
 281         .unlocked_ioctl = hidraw_ioctl,
 282 };
 283
 284 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 285 {
 286         struct hidraw *dev = hid->hidraw;
 287         struct hidraw_list *list;
 288
 289         list_for_each_entry(list, &dev->list, node) {
 290                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 291                 list->buffer[list->head].len = len;
 292                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 293                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 294         }
 295
 296         wake_up_interruptible(&dev->wait);
 297 }
 298 EXPORT_SYMBOL_GPL(hidraw_report_event);
 299
 300 int hidraw_connect(struct hid_device *hid)
 301 {
 302         int minor, result;
 303         struct hidraw *dev;
 304
 305         /* TODO currently we accept any HID device. This should later
 306          * probably be fixed to accept only those devices which provide
 307          * non-input applications
 308          */
 309
 310         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 311         if (!dev)
 312                 return -ENOMEM;
 313
 314         result = -EINVAL;
 315
 316         mutex_lock(&minors_lock);
 317
 318         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 319                 if (hidraw_table[minor])
 320                         continue;
 321                 hidraw_table[minor] = dev;
 322                 result = 0;
 323                 break;
 324         }
 325
 326         if (result) {
 327                 mutex_unlock(&minors_lock);
 328                 kfree(dev);
 329                 goto out;
 330         }
 331
 332         dev->dev = device_create(hidraw_class, NULL, MKDEV(hidraw_major, minor),
 333                                  NULL, "%s%d", "hidraw", minor);
 334
 335         if (IS_ERR(dev->dev)) {
 336                 hidraw_table[minor] = NULL;
 337                 mutex_unlock(&minors_lock);
 338                 result = PTR_ERR(dev->dev);
 339                 kfree(dev);
 340                 goto out;
 341         }
 342
 343         mutex_unlock(&minors_lock);
 344         init_waitqueue_head(&dev->wait);
 345         INIT_LIST_HEAD(&dev->list);
 346
 347         dev->hid = hid;
 348         dev->minor = minor;
 349
 350         dev->exist = 1;
 351         hid->hidraw = dev;
 352
 353 out:
 354         return result;
 355
 356 }
 357 EXPORT_SYMBOL_GPL(hidraw_connect);
 358
 359 void hidraw_disconnect(struct hid_device *hid)
 360 {
 361         struct hidraw *hidraw = hid->hidraw;
 362
 363         hidraw->exist = 0;
 364
 365         mutex_lock(&minors_lock);
 366         hidraw_table[hidraw->minor] = NULL;
 367         mutex_unlock(&minors_lock);
 368
 369         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 370
 371         if (hidraw->open) {
 372                 hid->ll_driver->close(hid);
 373                 wake_up_interruptible(&hidraw->wait);
 374         } else {
 375                 kfree(hidraw);
 376         }
 377 }
 378 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 379
 380 int __init hidraw_init(void)
 381 {
 382         int result;
 383         dev_t dev_id;
 384
 385         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 386                         HIDRAW_MAX_DEVICES, "hidraw");
 387
 388         hidraw_major = MAJOR(dev_id);
 389
 390         if (result < 0) {
 391                 printk(KERN_WARNING "hidraw: can't get major number\n");
 392                 result = 0;
 393                 goto out;
 394         }
 395
 396         hidraw_class = class_create(THIS_MODULE, "hidraw");
 397         if (IS_ERR(hidraw_class)) {
 398                 result = PTR_ERR(hidraw_class);
 399                 unregister_chrdev(hidraw_major, "hidraw");
 400                 goto out;
 401         }
 402
 403         cdev_init(&hidraw_cdev, &hidraw_ops);
 404         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 405 out:
 406         return result;
 407 }
 408
 409 void hidraw_exit(void)
 410 {
 411         dev_t dev_id = MKDEV(hidraw_major, 0);
 412
 413         cdev_del(&hidraw_cdev);
 414         class_destroy(hidraw_class);
 415         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 416
 417 }