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_SPINLOCK(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         while (ret == 0) {
  51
  52                 mutex_lock(&list->read_mutex);
  53
  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 = 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_MIN_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         lock_kernel();
 162         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 163                 err = -ENOMEM;
 164                 goto out;
 165         }
 166
 167         spin_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                 dev->hid->hid_open(dev->hid);
 184
 185 out_unlock:
 186         spin_unlock(&minors_lock);
 187 out:
 188         unlock_kernel();
 189         return err;
 190
 191 }
 192
 193 static int hidraw_release(struct inode * inode, struct file * file)
 194 {
 195         unsigned int minor = iminor(inode);
 196         struct hidraw *dev;
 197         struct hidraw_list *list = file->private_data;
 198
 199         if (!hidraw_table[minor]) {
 200                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 201                                 minor);
 202                 return -ENODEV;
 203         }
 204
 205         list_del(&list->node);
 206         dev = hidraw_table[minor];
 207         if (!dev->open--) {
 208                 if (list->hidraw->exist)
 209                         dev->hid->hid_close(dev->hid);
 210                 else
 211                         kfree(list->hidraw);
 212         }
 213
 214         return 0;
 215 }
 216
 217 static int hidraw_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 218 {
 219         unsigned int minor = iminor(inode);
 220         struct hidraw *dev = hidraw_table[minor];
 221         void __user *user_arg = (void __user*) arg;
 222
 223         switch (cmd) {
 224                 case HIDIOCGRDESCSIZE:
 225                         if (put_user(dev->hid->rsize, (int __user *)arg))
 226                                 return -EFAULT;
 227                         return 0;
 228
 229                 case HIDIOCGRDESC:
 230                         {
 231                                 __u32 len;
 232
 233                                 if (get_user(len, (int __user *)arg))
 234                                         return -EFAULT;
 235
 236                                 if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 237                                         return -EINVAL;
 238
 239                                 if (copy_to_user(user_arg + offsetof(
 240                                                                 struct hidraw_report_descriptor,
 241                                                                 value[0]),
 242                                                         dev->hid->rdesc,
 243                                                         min(dev->hid->rsize, len)))
 244                                                 return -EFAULT;
 245                                 return 0;
 246                         }
 247                 case HIDIOCGRAWINFO:
 248                         {
 249                                 struct hidraw_devinfo dinfo;
 250
 251                                 dinfo.bustype = dev->hid->bus;
 252                                 dinfo.vendor = dev->hid->vendor;
 253                                 dinfo.product = dev->hid->product;
 254                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 255                                         return -EFAULT;
 256
 257                                 return 0;
 258                         }
 259                 default:
 260                         printk(KERN_EMERG "hidraw: unsupported ioctl() %x\n",
 261                                         cmd);
 262         }
 263         return -EINVAL;
 264 }
 265
 266 static const struct file_operations hidraw_ops = {
 267         .owner =        THIS_MODULE,
 268         .read =         hidraw_read,
 269         .write =        hidraw_write,
 270         .poll =         hidraw_poll,
 271         .open =         hidraw_open,
 272         .release =      hidraw_release,
 273         .ioctl =        hidraw_ioctl,
 274 };
 275
 276 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 277 {
 278         struct hidraw *dev = hid->hidraw;
 279         struct hidraw_list *list;
 280
 281         list_for_each_entry(list, &dev->list, node) {
 282                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 283                 list->buffer[list->head].len = len;
 284                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 285                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 286         }
 287
 288         wake_up_interruptible(&dev->wait);
 289 }
 290 EXPORT_SYMBOL_GPL(hidraw_report_event);
 291
 292 int hidraw_connect(struct hid_device *hid)
 293 {
 294         int minor, result;
 295         struct hidraw *dev;
 296
 297         /* TODO currently we accept any HID device. This should later
 298          * probably be fixed to accept only those devices which provide
 299          * non-input applications
 300          */
 301
 302         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 303         if (!dev)
 304                 return -ENOMEM;
 305
 306         result = -EINVAL;
 307
 308         spin_lock(&minors_lock);
 309
 310         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 311                 if (hidraw_table[minor])
 312                         continue;
 313                 hidraw_table[minor] = dev;
 314                 result = 0;
 315                 break;
 316         }
 317
 318         spin_unlock(&minors_lock);
 319
 320         if (result) {
 321                 kfree(dev);
 322                 goto out;
 323         }
 324
 325         dev->dev = device_create(hidraw_class, NULL, MKDEV(hidraw_major, minor),
 326                                 "%s%d", "hidraw", minor);
 327
 328         if (IS_ERR(dev->dev)) {
 329                 spin_lock(&minors_lock);
 330                 hidraw_table[minor] = NULL;
 331                 spin_unlock(&minors_lock);
 332                 result = PTR_ERR(dev->dev);
 333                 kfree(dev);
 334                 goto out;
 335         }
 336
 337         init_waitqueue_head(&dev->wait);
 338         INIT_LIST_HEAD(&dev->list);
 339
 340         dev->hid = hid;
 341         dev->minor = minor;
 342
 343         dev->exist = 1;
 344         hid->hidraw = dev;
 345
 346 out:
 347         return result;
 348
 349 }
 350 EXPORT_SYMBOL_GPL(hidraw_connect);
 351
 352 void hidraw_disconnect(struct hid_device *hid)
 353 {
 354         struct hidraw *hidraw = hid->hidraw;
 355
 356         hidraw->exist = 0;
 357
 358         spin_lock(&minors_lock);
 359         hidraw_table[hidraw->minor] = NULL;
 360         spin_unlock(&minors_lock);
 361
 362         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 363
 364         if (hidraw->open) {
 365                 hid->hid_close(hid);
 366                 wake_up_interruptible(&hidraw->wait);
 367         } else {
 368                 kfree(hidraw);
 369         }
 370 }
 371 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 372
 373 int __init hidraw_init(void)
 374 {
 375         int result;
 376         dev_t dev_id;
 377
 378         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 379                         HIDRAW_MAX_DEVICES, "hidraw");
 380
 381         hidraw_major = MAJOR(dev_id);
 382
 383         if (result < 0) {
 384                 printk(KERN_WARNING "hidraw: can't get major number\n");
 385                 result = 0;
 386                 goto out;
 387         }
 388
 389         hidraw_class = class_create(THIS_MODULE, "hidraw");
 390         if (IS_ERR(hidraw_class)) {
 391                 result = PTR_ERR(hidraw_class);
 392                 unregister_chrdev(hidraw_major, "hidraw");
 393                 goto out;
 394         }
 395
 396         cdev_init(&hidraw_cdev, &hidraw_ops);
 397         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 398 out:
 399         return result;
 400 }
 401
 402 void __exit hidraw_exit(void)
 403 {
 404         dev_t dev_id = MKDEV(hidraw_major, 0);
 405
 406         cdev_del(&hidraw_cdev);
 407         class_destroy(hidraw_class);
 408         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 409
 410 }