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/sched.h>
  34 #include <linux/smp_lock.h>
  35
  36 #include <linux/hidraw.h>
  37
  38 static int hidraw_major;
  39 static struct cdev hidraw_cdev;
  40 static struct class *hidraw_class;
  41 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
  42 static DEFINE_MUTEX(minors_lock);
  43
  44 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
  45 {
  46         struct hidraw_list *list = file->private_data;
  47         int ret = 0, len;
  48         char *report;
  49         DECLARE_WAITQUEUE(wait, current);
  50
  51         mutex_lock(&list->read_mutex);
  52
  53         while (ret == 0) {
  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         struct hid_device *dev;
 109         __u8 *buf;
 110         int ret = 0;
 111
 112         if (!hidraw_table[minor])
 113                 return -ENODEV;
 114
 115         dev = hidraw_table[minor]->hid;
 116
 117         if (!dev->hid_output_raw_report)
 118                 return -ENODEV;
 119
 120         if (count > HID_MAX_BUFFER_SIZE) {
 121                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 122                                 task_pid_nr(current));
 123                 return -EINVAL;
 124         }
 125
 126         if (count < 2) {
 127                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 128                                 task_pid_nr(current));
 129                 return -EINVAL;
 130         }
 131
 132         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 133         if (!buf)
 134                 return -ENOMEM;
 135
 136         if (copy_from_user(buf, buffer, count)) {
 137                 ret = -EFAULT;
 138                 goto out;
 139         }
 140
 141         ret = dev->hid_output_raw_report(dev, buf, count);
 142 out:
 143         kfree(buf);
 144         return ret;
 145 }
 146
 147 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 148 {
 149         struct hidraw_list *list = file->private_data;
 150
 151         poll_wait(file, &list->hidraw->wait, wait);
 152         if (list->head != list->tail)
 153                 return POLLIN | POLLRDNORM;
 154         if (!list->hidraw->exist)
 155                 return POLLERR | POLLHUP;
 156         return 0;
 157 }
 158
 159 static int hidraw_open(struct inode *inode, struct file *file)
 160 {
 161         unsigned int minor = iminor(inode);
 162         struct hidraw *dev;
 163         struct hidraw_list *list;
 164         int err = 0;
 165
 166         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 167                 err = -ENOMEM;
 168                 goto out;
 169         }
 170
 171         lock_kernel();
 172         mutex_lock(&minors_lock);
 173         if (!hidraw_table[minor]) {
 174                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 175                                 minor);
 176                 kfree(list);
 177                 err = -ENODEV;
 178                 goto out_unlock;
 179         }
 180
 181         list->hidraw = hidraw_table[minor];
 182         mutex_init(&list->read_mutex);
 183         list_add_tail(&list->node, &hidraw_table[minor]->list);
 184         file->private_data = list;
 185
 186         dev = hidraw_table[minor];
 187         if (!dev->open++) {
 188                 if (dev->hid->ll_driver->power) {
 189                         err = dev->hid->ll_driver->power(dev->hid, PM_HINT_FULLON);
 190                         if (err < 0)
 191                                 goto out_unlock;
 192                 }
 193                 err = dev->hid->ll_driver->open(dev->hid);
 194                 if (err < 0) {
 195                         if (dev->hid->ll_driver->power)
 196                                 dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
 197                         dev->open--;
 198                 }
 199         }
 200
 201 out_unlock:
 202         mutex_unlock(&minors_lock);
 203         unlock_kernel();
 204 out:
 205         return err;
 206
 207 }
 208
 209 static int hidraw_release(struct inode * inode, struct file * file)
 210 {
 211         unsigned int minor = iminor(inode);
 212         struct hidraw *dev;
 213         struct hidraw_list *list = file->private_data;
 214         int ret;
 215
 216         mutex_lock(&minors_lock);
 217         if (!hidraw_table[minor]) {
 218                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 219                                 minor);
 220                 ret = -ENODEV;
 221                 goto unlock;
 222         }
 223
 224         list_del(&list->node);
 225         dev = hidraw_table[minor];
 226         if (!--dev->open) {
 227                 if (list->hidraw->exist) {
 228                         if (dev->hid->ll_driver->power)
 229                                 dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
 230                         dev->hid->ll_driver->close(dev->hid);
 231                 } else {
 232                         kfree(list->hidraw);
 233                 }
 234         }
 235         kfree(list);
 236         ret = 0;
 237 unlock:
 238         mutex_unlock(&minors_lock);
 239
 240         return ret;
 241 }
 242
 243 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 244                                                         unsigned long arg)
 245 {
 246         struct inode *inode = file->f_path.dentry->d_inode;
 247         unsigned int minor = iminor(inode);
 248         long ret = 0;
 249         struct hidraw *dev;
 250         void __user *user_arg = (void __user*) arg;
 251
 252         lock_kernel();
 253         dev = hidraw_table[minor];
 254         if (!dev) {
 255                 ret = -ENODEV;
 256                 goto out;
 257         }
 258
 259         switch (cmd) {
 260                 case HIDIOCGRDESCSIZE:
 261                         if (put_user(dev->hid->rsize, (int __user *)arg))
 262                                 ret = -EFAULT;
 263                         break;
 264
 265                 case HIDIOCGRDESC:
 266                         {
 267                                 __u32 len;
 268
 269                                 if (get_user(len, (int __user *)arg))
 270                                         ret = -EFAULT;
 271                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 272                                         ret = -EINVAL;
 273                                 else if (copy_to_user(user_arg + offsetof(
 274                                         struct hidraw_report_descriptor,
 275                                         value[0]),
 276                                         dev->hid->rdesc,
 277                                         min(dev->hid->rsize, len)))
 278                                         ret = -EFAULT;
 279                                 break;
 280                         }
 281                 case HIDIOCGRAWINFO:
 282                         {
 283                                 struct hidraw_devinfo dinfo;
 284
 285                                 dinfo.bustype = dev->hid->bus;
 286                                 dinfo.vendor = dev->hid->vendor;
 287                                 dinfo.product = dev->hid->product;
 288                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 289                                         ret = -EFAULT;
 290                                 break;
 291                         }
 292                 default:
 293                         {
 294                                 struct hid_device *hid = dev->hid;
 295                                 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
 296                                         ret = -EINVAL;
 297                                         break;
 298                                 }
 299
 300                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 301                                         int len;
 302                                         if (!hid->name) {
 303                                                 ret = 0;
 304                                                 break;
 305                                         }
 306                                         len = strlen(hid->name) + 1;
 307                                         if (len > _IOC_SIZE(cmd))
 308                                                 len = _IOC_SIZE(cmd);
 309                                         ret = copy_to_user(user_arg, hid->name, len) ?
 310                                                 -EFAULT : len;
 311                                         break;
 312                                 }
 313
 314                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 315                                         int len;
 316                                         if (!hid->phys) {
 317                                                 ret = 0;
 318                                                 break;
 319                                         }
 320                                         len = strlen(hid->phys) + 1;
 321                                         if (len > _IOC_SIZE(cmd))
 322                                                 len = _IOC_SIZE(cmd);
 323                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 324                                                 -EFAULT : len;
 325                                         break;
 326                                 }
 327                 }
 328
 329                 ret = -ENOTTY;
 330         }
 331 out:
 332         unlock_kernel();
 333         return ret;
 334 }
 335
 336 static const struct file_operations hidraw_ops = {
 337         .owner =        THIS_MODULE,
 338         .read =         hidraw_read,
 339         .write =        hidraw_write,
 340         .poll =         hidraw_poll,
 341         .open =         hidraw_open,
 342         .release =      hidraw_release,
 343         .unlocked_ioctl = hidraw_ioctl,
 344 };
 345
 346 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 347 {
 348         struct hidraw *dev = hid->hidraw;
 349         struct hidraw_list *list;
 350
 351         list_for_each_entry(list, &dev->list, node) {
 352                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 353                 list->buffer[list->head].len = len;
 354                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 355                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 356         }
 357
 358         wake_up_interruptible(&dev->wait);
 359 }
 360 EXPORT_SYMBOL_GPL(hidraw_report_event);
 361
 362 int hidraw_connect(struct hid_device *hid)
 363 {
 364         int minor, result;
 365         struct hidraw *dev;
 366
 367         /* we accept any HID device, no matter the applications */
 368
 369         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 370         if (!dev)
 371                 return -ENOMEM;
 372
 373         result = -EINVAL;
 374
 375         mutex_lock(&minors_lock);
 376
 377         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 378                 if (hidraw_table[minor])
 379                         continue;
 380                 hidraw_table[minor] = dev;
 381                 result = 0;
 382                 break;
 383         }
 384
 385         if (result) {
 386                 mutex_unlock(&minors_lock);
 387                 kfree(dev);
 388                 goto out;
 389         }
 390
 391         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 392                                  NULL, "%s%d", "hidraw", minor);
 393
 394         if (IS_ERR(dev->dev)) {
 395                 hidraw_table[minor] = NULL;
 396                 mutex_unlock(&minors_lock);
 397                 result = PTR_ERR(dev->dev);
 398                 kfree(dev);
 399                 goto out;
 400         }
 401
 402         mutex_unlock(&minors_lock);
 403         init_waitqueue_head(&dev->wait);
 404         INIT_LIST_HEAD(&dev->list);
 405
 406         dev->hid = hid;
 407         dev->minor = minor;
 408
 409         dev->exist = 1;
 410         hid->hidraw = dev;
 411
 412 out:
 413         return result;
 414
 415 }
 416 EXPORT_SYMBOL_GPL(hidraw_connect);
 417
 418 void hidraw_disconnect(struct hid_device *hid)
 419 {
 420         struct hidraw *hidraw = hid->hidraw;
 421
 422         hidraw->exist = 0;
 423
 424         mutex_lock(&minors_lock);
 425         hidraw_table[hidraw->minor] = NULL;
 426         mutex_unlock(&minors_lock);
 427
 428         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 429
 430         if (hidraw->open) {
 431                 hid->ll_driver->close(hid);
 432                 wake_up_interruptible(&hidraw->wait);
 433         } else {
 434                 kfree(hidraw);
 435         }
 436 }
 437 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 438
 439 int __init hidraw_init(void)
 440 {
 441         int result;
 442         dev_t dev_id;
 443
 444         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 445                         HIDRAW_MAX_DEVICES, "hidraw");
 446
 447         hidraw_major = MAJOR(dev_id);
 448
 449         if (result < 0) {
 450                 printk(KERN_WARNING "hidraw: can't get major number\n");
 451                 result = 0;
 452                 goto out;
 453         }
 454
 455         hidraw_class = class_create(THIS_MODULE, "hidraw");
 456         if (IS_ERR(hidraw_class)) {
 457                 result = PTR_ERR(hidraw_class);
 458                 unregister_chrdev(hidraw_major, "hidraw");
 459                 goto out;
 460         }
 461
 462         cdev_init(&hidraw_cdev, &hidraw_ops);
 463         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 464 out:
 465         return result;
 466 }
 467
 468 void hidraw_exit(void)
 469 {
 470         dev_t dev_id = MKDEV(hidraw_major, 0);
 471
 472         cdev_del(&hidraw_cdev);
 473         class_destroy(hidraw_class);
 474         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 475
 476 }