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/slab.h>
  32 #include <linux/hid.h>
  33 #include <linux/mutex.h>
  34 #include <linux/sched.h>
  35 #include <linux/smp_lock.h>
  36
  37 #include <linux/hidraw.h>
  38
  39 static int hidraw_major;
  40 static struct cdev hidraw_cdev;
  41 static struct class *hidraw_class;
  42 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
  43 static DEFINE_MUTEX(minors_lock);
  44
  45 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
  46 {
  47         struct hidraw_list *list = file->private_data;
  48         int ret = 0, len;
  49         char *report;
  50         DECLARE_WAITQUEUE(wait, current);
  51
  52         mutex_lock(&list->read_mutex);
  53
  54         while (ret == 0) {
  55                 if (list->head == list->tail) {
  56                         add_wait_queue(&list->hidraw->wait, &wait);
  57                         set_current_state(TASK_INTERRUPTIBLE);
  58
  59                         while (list->head == list->tail) {
  60                                 if (file->f_flags & O_NONBLOCK) {
  61                                         ret = -EAGAIN;
  62                                         break;
  63                                 }
  64                                 if (signal_pending(current)) {
  65                                         ret = -ERESTARTSYS;
  66                                         break;
  67                                 }
  68                                 if (!list->hidraw->exist) {
  69                                         ret = -EIO;
  70                                         break;
  71                                 }
  72
  73                                 /* allow O_NONBLOCK to work well from other threads */
  74                                 mutex_unlock(&list->read_mutex);
  75                                 schedule();
  76                                 mutex_lock(&list->read_mutex);
  77                                 set_current_state(TASK_INTERRUPTIBLE);
  78                         }
  79
  80                         set_current_state(TASK_RUNNING);
  81                         remove_wait_queue(&list->hidraw->wait, &wait);
  82                 }
  83
  84                 if (ret)
  85                         goto out;
  86
  87                 report = list->buffer[list->tail].value;
  88                 len = list->buffer[list->tail].len > count ?
  89                         count : list->buffer[list->tail].len;
  90
  91                 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
  92                         ret = -EFAULT;
  93                         goto out;
  94                 }
  95                 ret += len;
  96
  97                 kfree(list->buffer[list->tail].value);
  98                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
  99         }
 100 out:
 101         mutex_unlock(&list->read_mutex);
 102         return ret;
 103 }
 104
 105 /* the first byte is expected to be a report number */
 106 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 107 {
 108         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 109         struct hid_device *dev;
 110         __u8 *buf;
 111         int ret = 0;
 112
 113         mutex_lock(&minors_lock);
 114
 115         if (!hidraw_table[minor]) {
 116                 ret = -ENODEV;
 117                 goto out;
 118         }
 119
 120         dev = hidraw_table[minor]->hid;
 121
 122         if (!dev->hid_output_raw_report) {
 123                 ret = -ENODEV;
 124                 goto out;
 125         }
 126
 127         if (count > HID_MAX_BUFFER_SIZE) {
 128                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 129                                 task_pid_nr(current));
 130                 ret = -EINVAL;
 131                 goto out;
 132         }
 133
 134         if (count < 2) {
 135                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 136                                 task_pid_nr(current));
 137                 ret = -EINVAL;
 138                 goto out;
 139         }
 140
 141         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 142         if (!buf) {
 143                 ret = -ENOMEM;
 144                 goto out;
 145         }
 146
 147         if (copy_from_user(buf, buffer, count)) {
 148                 ret = -EFAULT;
 149                 goto out_free;
 150         }
 151
 152         ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT);
 153 out_free:
 154         kfree(buf);
 155 out:
 156         mutex_unlock(&minors_lock);
 157         return ret;
 158 }
 159
 160 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 161 {
 162         struct hidraw_list *list = file->private_data;
 163
 164         poll_wait(file, &list->hidraw->wait, wait);
 165         if (list->head != list->tail)
 166                 return POLLIN | POLLRDNORM;
 167         if (!list->hidraw->exist)
 168                 return POLLERR | POLLHUP;
 169         return 0;
 170 }
 171
 172 static int hidraw_open(struct inode *inode, struct file *file)
 173 {
 174         unsigned int minor = iminor(inode);
 175         struct hidraw *dev;
 176         struct hidraw_list *list;
 177         int err = 0;
 178
 179         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 180                 err = -ENOMEM;
 181                 goto out;
 182         }
 183
 184         mutex_lock(&minors_lock);
 185         if (!hidraw_table[minor]) {
 186                 kfree(list);
 187                 err = -ENODEV;
 188                 goto out_unlock;
 189         }
 190
 191         list->hidraw = hidraw_table[minor];
 192         mutex_init(&list->read_mutex);
 193         list_add_tail(&list->node, &hidraw_table[minor]->list);
 194         file->private_data = list;
 195
 196         dev = hidraw_table[minor];
 197         if (!dev->open++) {
 198                 if (dev->hid->ll_driver->power) {
 199                         err = dev->hid->ll_driver->power(dev->hid, PM_HINT_FULLON);
 200                         if (err < 0)
 201                                 goto out_unlock;
 202                 }
 203                 err = dev->hid->ll_driver->open(dev->hid);
 204                 if (err < 0) {
 205                         if (dev->hid->ll_driver->power)
 206                                 dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
 207                         dev->open--;
 208                 }
 209         }
 210
 211 out_unlock:
 212         mutex_unlock(&minors_lock);
 213 out:
 214         return err;
 215
 216 }
 217
 218 static int hidraw_release(struct inode * inode, struct file * file)
 219 {
 220         unsigned int minor = iminor(inode);
 221         struct hidraw *dev;
 222         struct hidraw_list *list = file->private_data;
 223
 224         if (!hidraw_table[minor])
 225                 return -ENODEV;
 226
 227         list_del(&list->node);
 228         dev = hidraw_table[minor];
 229         if (!--dev->open) {
 230                 if (list->hidraw->exist) {
 231                         if (dev->hid->ll_driver->power)
 232                                 dev->hid->ll_driver->power(dev->hid, PM_HINT_NORMAL);
 233                         dev->hid->ll_driver->close(dev->hid);
 234                 } else {
 235                         kfree(list->hidraw);
 236                 }
 237         }
 238
 239         kfree(list);
 240
 241         return 0;
 242 }
 243
 244 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 245                                                         unsigned long arg)
 246 {
 247         struct inode *inode = file->f_path.dentry->d_inode;
 248         unsigned int minor = iminor(inode);
 249         long ret = 0;
 250         struct hidraw *dev;
 251         void __user *user_arg = (void __user*) arg;
 252
 253         mutex_lock(&minors_lock);
 254         dev = hidraw_table[minor];
 255         if (!dev) {
 256                 ret = -ENODEV;
 257                 goto out;
 258         }
 259
 260         switch (cmd) {
 261                 case HIDIOCGRDESCSIZE:
 262                         if (put_user(dev->hid->rsize, (int __user *)arg))
 263                                 ret = -EFAULT;
 264                         break;
 265
 266                 case HIDIOCGRDESC:
 267                         {
 268                                 __u32 len;
 269
 270                                 if (get_user(len, (int __user *)arg))
 271                                         ret = -EFAULT;
 272                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 273                                         ret = -EINVAL;
 274                                 else if (copy_to_user(user_arg + offsetof(
 275                                         struct hidraw_report_descriptor,
 276                                         value[0]),
 277                                         dev->hid->rdesc,
 278                                         min(dev->hid->rsize, len)))
 279                                         ret = -EFAULT;
 280                                 break;
 281                         }
 282                 case HIDIOCGRAWINFO:
 283                         {
 284                                 struct hidraw_devinfo dinfo;
 285
 286                                 dinfo.bustype = dev->hid->bus;
 287                                 dinfo.vendor = dev->hid->vendor;
 288                                 dinfo.product = dev->hid->product;
 289                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 290                                         ret = -EFAULT;
 291                                 break;
 292                         }
 293                 default:
 294                         {
 295                                 struct hid_device *hid = dev->hid;
 296                                 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
 297                                         ret = -EINVAL;
 298                                         break;
 299                                 }
 300
 301                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 302                                         int len;
 303                                         if (!hid->name) {
 304                                                 ret = 0;
 305                                                 break;
 306                                         }
 307                                         len = strlen(hid->name) + 1;
 308                                         if (len > _IOC_SIZE(cmd))
 309                                                 len = _IOC_SIZE(cmd);
 310                                         ret = copy_to_user(user_arg, hid->name, len) ?
 311                                                 -EFAULT : len;
 312                                         break;
 313                                 }
 314
 315                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 316                                         int len;
 317                                         if (!hid->phys) {
 318                                                 ret = 0;
 319                                                 break;
 320                                         }
 321                                         len = strlen(hid->phys) + 1;
 322                                         if (len > _IOC_SIZE(cmd))
 323                                                 len = _IOC_SIZE(cmd);
 324                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 325                                                 -EFAULT : len;
 326                                         break;
 327                                 }
 328                 }
 329
 330                 ret = -ENOTTY;
 331         }
 332 out:
 333         mutex_unlock(&minors_lock);
 334         return ret;
 335 }
 336
 337 static const struct file_operations hidraw_ops = {
 338         .owner =        THIS_MODULE,
 339         .read =         hidraw_read,
 340         .write =        hidraw_write,
 341         .poll =         hidraw_poll,
 342         .open =         hidraw_open,
 343         .release =      hidraw_release,
 344         .unlocked_ioctl = hidraw_ioctl,
 345 };
 346
 347 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 348 {
 349         struct hidraw *dev = hid->hidraw;
 350         struct hidraw_list *list;
 351
 352         list_for_each_entry(list, &dev->list, node) {
 353                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 354                 list->buffer[list->head].len = len;
 355                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 356                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 357         }
 358
 359         wake_up_interruptible(&dev->wait);
 360 }
 361 EXPORT_SYMBOL_GPL(hidraw_report_event);
 362
 363 int hidraw_connect(struct hid_device *hid)
 364 {
 365         int minor, result;
 366         struct hidraw *dev;
 367
 368         /* we accept any HID device, no matter the applications */
 369
 370         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 371         if (!dev)
 372                 return -ENOMEM;
 373
 374         result = -EINVAL;
 375
 376         mutex_lock(&minors_lock);
 377
 378         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 379                 if (hidraw_table[minor])
 380                         continue;
 381                 hidraw_table[minor] = dev;
 382                 result = 0;
 383                 break;
 384         }
 385
 386         if (result) {
 387                 mutex_unlock(&minors_lock);
 388                 kfree(dev);
 389                 goto out;
 390         }
 391
 392         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 393                                  NULL, "%s%d", "hidraw", minor);
 394
 395         if (IS_ERR(dev->dev)) {
 396                 hidraw_table[minor] = NULL;
 397                 mutex_unlock(&minors_lock);
 398                 result = PTR_ERR(dev->dev);
 399                 kfree(dev);
 400                 goto out;
 401         }
 402
 403         mutex_unlock(&minors_lock);
 404         init_waitqueue_head(&dev->wait);
 405         INIT_LIST_HEAD(&dev->list);
 406
 407         dev->hid = hid;
 408         dev->minor = minor;
 409
 410         dev->exist = 1;
 411         hid->hidraw = dev;
 412
 413 out:
 414         return result;
 415
 416 }
 417 EXPORT_SYMBOL_GPL(hidraw_connect);
 418
 419 void hidraw_disconnect(struct hid_device *hid)
 420 {
 421         struct hidraw *hidraw = hid->hidraw;
 422
 423         hidraw->exist = 0;
 424
 425         mutex_lock(&minors_lock);
 426         hidraw_table[hidraw->minor] = NULL;
 427         mutex_unlock(&minors_lock);
 428
 429         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 430
 431         if (hidraw->open) {
 432                 hid->ll_driver->close(hid);
 433                 wake_up_interruptible(&hidraw->wait);
 434         } else {
 435                 kfree(hidraw);
 436         }
 437 }
 438 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 439
 440 int __init hidraw_init(void)
 441 {
 442         int result;
 443         dev_t dev_id;
 444
 445         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 446                         HIDRAW_MAX_DEVICES, "hidraw");
 447
 448         hidraw_major = MAJOR(dev_id);
 449
 450         if (result < 0) {
 451                 printk(KERN_WARNING "hidraw: can't get major number\n");
 452                 result = 0;
 453                 goto out;
 454         }
 455
 456         hidraw_class = class_create(THIS_MODULE, "hidraw");
 457         if (IS_ERR(hidraw_class)) {
 458                 result = PTR_ERR(hidraw_class);
 459                 unregister_chrdev(hidraw_major, "hidraw");
 460                 goto out;
 461         }
 462
 463         cdev_init(&hidraw_cdev, &hidraw_ops);
 464         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 465 out:
 466         return result;
 467 }
 468
 469 void hidraw_exit(void)
 470 {
 471         dev_t dev_id = MKDEV(hidraw_major, 0);
 472
 473         cdev_del(&hidraw_cdev);
 474         class_destroy(hidraw_class);
 475         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 476
 477 }