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         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                 len = list->buffer[list->tail].len > count ?
  87                         count : list->buffer[list->tail].len;
  88
  89                 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
  90                         ret = -EFAULT;
  91                         goto out;
  92                 }
  93                 ret += len;
  94
  95                 kfree(list->buffer[list->tail].value);
  96                 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
  97         }
  98 out:
  99         mutex_unlock(&list->read_mutex);
 100         return ret;
 101 }
 102
 103 /* the first byte is expected to be a report number */
 104 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
 105 {
 106         unsigned int minor = iminor(file->f_path.dentry->d_inode);
 107         struct hid_device *dev;
 108         __u8 *buf;
 109         int ret = 0;
 110
 111         mutex_lock(&minors_lock);
 112
 113         if (!hidraw_table[minor]) {
 114                 ret = -ENODEV;
 115                 goto out;
 116         }
 117
 118         dev = hidraw_table[minor]->hid;
 119
 120         if (!dev->hid_output_raw_report) {
 121                 ret = -ENODEV;
 122                 goto out;
 123         }
 124
 125         if (count > HID_MAX_BUFFER_SIZE) {
 126                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 127                                 task_pid_nr(current));
 128                 ret = -EINVAL;
 129                 goto out;
 130         }
 131
 132         if (count < 2) {
 133                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 134                                 task_pid_nr(current));
 135                 ret = -EINVAL;
 136                 goto out;
 137         }
 138
 139         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 140         if (!buf) {
 141                 ret = -ENOMEM;
 142                 goto out;
 143         }
 144
 145         if (copy_from_user(buf, buffer, count)) {
 146                 ret = -EFAULT;
 147                 goto out_free;
 148         }
 149
 150         ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT);
 151 out_free:
 152         kfree(buf);
 153 out:
 154         mutex_unlock(&minors_lock);
 155         return ret;
 156 }
 157
 158 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 159 {
 160         struct hidraw_list *list = file->private_data;
 161
 162         poll_wait(file, &list->hidraw->wait, wait);
 163         if (list->head != list->tail)
 164                 return POLLIN | POLLRDNORM;
 165         if (!list->hidraw->exist)
 166                 return POLLERR | POLLHUP;
 167         return 0;
 168 }
 169
 170 static int hidraw_open(struct inode *inode, struct file *file)
 171 {
 172         unsigned int minor = iminor(inode);
 173         struct hidraw *dev;
 174         struct hidraw_list *list;
 175         int err = 0;
 176
 177         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 178                 err = -ENOMEM;
 179                 goto out;
 180         }
 181
 182         mutex_lock(&minors_lock);
 183         if (!hidraw_table[minor]) {
 184                 kfree(list);
 185                 err = -ENODEV;
 186                 goto out_unlock;
 187         }
 188
 189         list->hidraw = hidraw_table[minor];
 190         mutex_init(&list->read_mutex);
 191         list_add_tail(&list->node, &hidraw_table[minor]->list);
 192         file->private_data = list;
 193
 194         dev = hidraw_table[minor];
 195         if (!dev->open++) {
 196                 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
 197                 if (err < 0)
 198                         goto out_unlock;
 199
 200                 err = hid_hw_open(dev->hid);
 201                 if (err < 0) {
 202                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 203                         dev->open--;
 204                 }
 205         }
 206
 207 out_unlock:
 208         mutex_unlock(&minors_lock);
 209 out:
 210         return err;
 211
 212 }
 213
 214 static int hidraw_release(struct inode * inode, struct file * file)
 215 {
 216         unsigned int minor = iminor(inode);
 217         struct hidraw *dev;
 218         struct hidraw_list *list = file->private_data;
 219         int ret;
 220
 221         mutex_lock(&minors_lock);
 222         if (!hidraw_table[minor]) {
 223                 ret = -ENODEV;
 224                 goto unlock;
 225         }
 226
 227         list_del(&list->node);
 228         dev = hidraw_table[minor];
 229         if (!--dev->open) {
 230                 if (list->hidraw->exist) {
 231                         hid_hw_power(dev->hid, PM_HINT_NORMAL);
 232                         hid_hw_close(dev->hid);
 233                 } else {
 234                         kfree(list->hidraw);
 235                 }
 236         }
 237         kfree(list);
 238         ret = 0;
 239 unlock:
 240         mutex_unlock(&minors_lock);
 241
 242         return ret;
 243 }
 244
 245 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 246                                                         unsigned long arg)
 247 {
 248         struct inode *inode = file->f_path.dentry->d_inode;
 249         unsigned int minor = iminor(inode);
 250         long ret = 0;
 251         struct hidraw *dev;
 252         void __user *user_arg = (void __user*) arg;
 253
 254         mutex_lock(&minors_lock);
 255         dev = hidraw_table[minor];
 256         if (!dev) {
 257                 ret = -ENODEV;
 258                 goto out;
 259         }
 260
 261         switch (cmd) {
 262                 case HIDIOCGRDESCSIZE:
 263                         if (put_user(dev->hid->rsize, (int __user *)arg))
 264                                 ret = -EFAULT;
 265                         break;
 266
 267                 case HIDIOCGRDESC:
 268                         {
 269                                 __u32 len;
 270
 271                                 if (get_user(len, (int __user *)arg))
 272                                         ret = -EFAULT;
 273                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 274                                         ret = -EINVAL;
 275                                 else if (copy_to_user(user_arg + offsetof(
 276                                         struct hidraw_report_descriptor,
 277                                         value[0]),
 278                                         dev->hid->rdesc,
 279                                         min(dev->hid->rsize, len)))
 280                                         ret = -EFAULT;
 281                                 break;
 282                         }
 283                 case HIDIOCGRAWINFO:
 284                         {
 285                                 struct hidraw_devinfo dinfo;
 286
 287                                 dinfo.bustype = dev->hid->bus;
 288                                 dinfo.vendor = dev->hid->vendor;
 289                                 dinfo.product = dev->hid->product;
 290                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 291                                         ret = -EFAULT;
 292                                 break;
 293                         }
 294                 default:
 295                         {
 296                                 struct hid_device *hid = dev->hid;
 297                                 if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
 298                                         ret = -EINVAL;
 299                                         break;
 300                                 }
 301
 302                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
 303                                         int len;
 304                                         if (!hid->name) {
 305                                                 ret = 0;
 306                                                 break;
 307                                         }
 308                                         len = strlen(hid->name) + 1;
 309                                         if (len > _IOC_SIZE(cmd))
 310                                                 len = _IOC_SIZE(cmd);
 311                                         ret = copy_to_user(user_arg, hid->name, len) ?
 312                                                 -EFAULT : len;
 313                                         break;
 314                                 }
 315
 316                                 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
 317                                         int len;
 318                                         if (!hid->phys) {
 319                                                 ret = 0;
 320                                                 break;
 321                                         }
 322                                         len = strlen(hid->phys) + 1;
 323                                         if (len > _IOC_SIZE(cmd))
 324                                                 len = _IOC_SIZE(cmd);
 325                                         ret = copy_to_user(user_arg, hid->phys, len) ?
 326                                                 -EFAULT : len;
 327                                         break;
 328                                 }
 329                 }
 330
 331                 ret = -ENOTTY;
 332         }
 333 out:
 334         mutex_unlock(&minors_lock);
 335         return ret;
 336 }
 337
 338 static const struct file_operations hidraw_ops = {
 339         .owner =        THIS_MODULE,
 340         .read =         hidraw_read,
 341         .write =        hidraw_write,
 342         .poll =         hidraw_poll,
 343         .open =         hidraw_open,
 344         .release =      hidraw_release,
 345         .unlocked_ioctl = hidraw_ioctl,
 346         .llseek =       noop_llseek,
 347 };
 348
 349 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 350 {
 351         struct hidraw *dev = hid->hidraw;
 352         struct hidraw_list *list;
 353
 354         list_for_each_entry(list, &dev->list, node) {
 355                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 356                 list->buffer[list->head].len = len;
 357                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 358                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 359         }
 360
 361         wake_up_interruptible(&dev->wait);
 362 }
 363 EXPORT_SYMBOL_GPL(hidraw_report_event);
 364
 365 int hidraw_connect(struct hid_device *hid)
 366 {
 367         int minor, result;
 368         struct hidraw *dev;
 369
 370         /* we accept any HID device, no matter the applications */
 371
 372         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 373         if (!dev)
 374                 return -ENOMEM;
 375
 376         result = -EINVAL;
 377
 378         mutex_lock(&minors_lock);
 379
 380         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 381                 if (hidraw_table[minor])
 382                         continue;
 383                 hidraw_table[minor] = dev;
 384                 result = 0;
 385                 break;
 386         }
 387
 388         if (result) {
 389                 mutex_unlock(&minors_lock);
 390                 kfree(dev);
 391                 goto out;
 392         }
 393
 394         dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
 395                                  NULL, "%s%d", "hidraw", minor);
 396
 397         if (IS_ERR(dev->dev)) {
 398                 hidraw_table[minor] = NULL;
 399                 mutex_unlock(&minors_lock);
 400                 result = PTR_ERR(dev->dev);
 401                 kfree(dev);
 402                 goto out;
 403         }
 404
 405         mutex_unlock(&minors_lock);
 406         init_waitqueue_head(&dev->wait);
 407         INIT_LIST_HEAD(&dev->list);
 408
 409         dev->hid = hid;
 410         dev->minor = minor;
 411
 412         dev->exist = 1;
 413         hid->hidraw = dev;
 414
 415 out:
 416         return result;
 417
 418 }
 419 EXPORT_SYMBOL_GPL(hidraw_connect);
 420
 421 void hidraw_disconnect(struct hid_device *hid)
 422 {
 423         struct hidraw *hidraw = hid->hidraw;
 424
 425         hidraw->exist = 0;
 426
 427         mutex_lock(&minors_lock);
 428         hidraw_table[hidraw->minor] = NULL;
 429         mutex_unlock(&minors_lock);
 430
 431         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 432
 433         if (hidraw->open) {
 434                 hid_hw_close(hid);
 435                 wake_up_interruptible(&hidraw->wait);
 436         } else {
 437                 kfree(hidraw);
 438         }
 439 }
 440 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 441
 442 int __init hidraw_init(void)
 443 {
 444         int result;
 445         dev_t dev_id;
 446
 447         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 448                         HIDRAW_MAX_DEVICES, "hidraw");
 449
 450         hidraw_major = MAJOR(dev_id);
 451
 452         if (result < 0) {
 453                 printk(KERN_WARNING "hidraw: can't get major number\n");
 454                 result = 0;
 455                 goto out;
 456         }
 457
 458         hidraw_class = class_create(THIS_MODULE, "hidraw");
 459         if (IS_ERR(hidraw_class)) {
 460                 result = PTR_ERR(hidraw_class);
 461                 unregister_chrdev(hidraw_major, "hidraw");
 462                 goto out;
 463         }
 464
 465         cdev_init(&hidraw_cdev, &hidraw_ops);
 466         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 467 out:
 468         return result;
 469 }
 470
 471 void hidraw_exit(void)
 472 {
 473         dev_t dev_id = MKDEV(hidraw_major, 0);
 474
 475         cdev_del(&hidraw_cdev);
 476         class_destroy(hidraw_class);
 477         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 478
 479 }