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