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