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         /* FIXME: What stops hidraw_table going NULL */
 109         struct hid_device *dev = hidraw_table[minor]->hid;
 110         __u8 *buf;
 111         int ret = 0;
 112
 113         if (!dev->hid_output_raw_report)
 114                 return -ENODEV;
 115
 116         if (count > HID_MIN_BUFFER_SIZE) {
 117                 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
 118                                 task_pid_nr(current));
 119                 return -EINVAL;
 120         }
 121
 122         if (count < 2) {
 123                 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
 124                                 task_pid_nr(current));
 125                 return -EINVAL;
 126         }
 127
 128         buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
 129         if (!buf)
 130                 return -ENOMEM;
 131
 132         if (copy_from_user(buf, buffer, count)) {
 133                 ret = -EFAULT;
 134                 goto out;
 135         }
 136
 137         ret = dev->hid_output_raw_report(dev, buf, count);
 138 out:
 139         kfree(buf);
 140         return ret;
 141 }
 142
 143 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 144 {
 145         struct hidraw_list *list = file->private_data;
 146
 147         poll_wait(file, &list->hidraw->wait, wait);
 148         if (list->head != list->tail)
 149                 return POLLIN | POLLRDNORM;
 150         if (!list->hidraw->exist)
 151                 return POLLERR | POLLHUP;
 152         return 0;
 153 }
 154
 155 static int hidraw_open(struct inode *inode, struct file *file)
 156 {
 157         unsigned int minor = iminor(inode);
 158         struct hidraw *dev;
 159         struct hidraw_list *list;
 160         int err = 0;
 161
 162         lock_kernel();
 163         if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
 164                 err = -ENOMEM;
 165                 goto out;
 166         }
 167
 168         spin_lock(&minors_lock);
 169         if (!hidraw_table[minor]) {
 170                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 171                                 minor);
 172                 kfree(list);
 173                 err = -ENODEV;
 174                 goto out_unlock;
 175         }
 176
 177         list->hidraw = hidraw_table[minor];
 178         mutex_init(&list->read_mutex);
 179         list_add_tail(&list->node, &hidraw_table[minor]->list);
 180         file->private_data = list;
 181
 182         dev = hidraw_table[minor];
 183         if (!dev->open++)
 184                 dev->hid->hid_open(dev->hid);
 185
 186 out_unlock:
 187         spin_unlock(&minors_lock);
 188 out:
 189         unlock_kernel();
 190         return err;
 191
 192 }
 193
 194 static int hidraw_release(struct inode * inode, struct file * file)
 195 {
 196         unsigned int minor = iminor(inode);
 197         struct hidraw *dev;
 198         struct hidraw_list *list = file->private_data;
 199
 200         if (!hidraw_table[minor]) {
 201                 printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n",
 202                                 minor);
 203                 return -ENODEV;
 204         }
 205
 206         list_del(&list->node);
 207         dev = hidraw_table[minor];
 208         if (!dev->open--) {
 209                 if (list->hidraw->exist)
 210                         dev->hid->hid_close(dev->hid);
 211                 else
 212                         kfree(list->hidraw);
 213         }
 214
 215         kfree(list);
 216
 217         return 0;
 218 }
 219
 220 static long hidraw_ioctl(struct file *file, unsigned int cmd,
 221                                                         unsigned long arg)
 222 {
 223         struct inode *inode = file->f_path.dentry->d_inode;
 224         unsigned int minor = iminor(inode);
 225         long ret = 0;
 226         /* FIXME: What stops hidraw_table going NULL */
 227         struct hidraw *dev = hidraw_table[minor];
 228         void __user *user_arg = (void __user*) arg;
 229
 230         lock_kernel();
 231         switch (cmd) {
 232                 case HIDIOCGRDESCSIZE:
 233                         if (put_user(dev->hid->rsize, (int __user *)arg))
 234                                 ret = -EFAULT;
 235                         break;
 236
 237                 case HIDIOCGRDESC:
 238                         {
 239                                 __u32 len;
 240
 241                                 if (get_user(len, (int __user *)arg))
 242                                         ret = -EFAULT;
 243                                 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
 244                                         ret = -EINVAL;
 245                                 else if (copy_to_user(user_arg + offsetof(
 246                                         struct hidraw_report_descriptor,
 247                                         value[0]),
 248                                         dev->hid->rdesc,
 249                                         min(dev->hid->rsize, len)))
 250                                         ret = -EFAULT;
 251                                 break;
 252                         }
 253                 case HIDIOCGRAWINFO:
 254                         {
 255                                 struct hidraw_devinfo dinfo;
 256
 257                                 dinfo.bustype = dev->hid->bus;
 258                                 dinfo.vendor = dev->hid->vendor;
 259                                 dinfo.product = dev->hid->product;
 260                                 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
 261                                         ret = -EFAULT;
 262                                 break;
 263                         }
 264                 default:
 265                         ret = -ENOTTY;
 266         }
 267         return ret;
 268 }
 269
 270 static const struct file_operations hidraw_ops = {
 271         .owner =        THIS_MODULE,
 272         .read =         hidraw_read,
 273         .write =        hidraw_write,
 274         .poll =         hidraw_poll,
 275         .open =         hidraw_open,
 276         .release =      hidraw_release,
 277         .unlocked_ioctl = hidraw_ioctl,
 278 };
 279
 280 void hidraw_report_event(struct hid_device *hid, u8 *data, int len)
 281 {
 282         struct hidraw *dev = hid->hidraw;
 283         struct hidraw_list *list;
 284
 285         list_for_each_entry(list, &dev->list, node) {
 286                 list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC);
 287                 list->buffer[list->head].len = len;
 288                 list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
 289                 kill_fasync(&list->fasync, SIGIO, POLL_IN);
 290         }
 291
 292         wake_up_interruptible(&dev->wait);
 293 }
 294 EXPORT_SYMBOL_GPL(hidraw_report_event);
 295
 296 int hidraw_connect(struct hid_device *hid)
 297 {
 298         int minor, result;
 299         struct hidraw *dev;
 300
 301         /* TODO currently we accept any HID device. This should later
 302          * probably be fixed to accept only those devices which provide
 303          * non-input applications
 304          */
 305
 306         dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
 307         if (!dev)
 308                 return -ENOMEM;
 309
 310         result = -EINVAL;
 311
 312         spin_lock(&minors_lock);
 313
 314         for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
 315                 if (hidraw_table[minor])
 316                         continue;
 317                 hidraw_table[minor] = dev;
 318                 result = 0;
 319                 break;
 320         }
 321
 322         spin_unlock(&minors_lock);
 323
 324         if (result) {
 325                 kfree(dev);
 326                 goto out;
 327         }
 328
 329         dev->dev = device_create_drvdata(hidraw_class, NULL,
 330                                          MKDEV(hidraw_major, minor), NULL,
 331                                          "%s%d", "hidraw", minor);
 332
 333         if (IS_ERR(dev->dev)) {
 334                 spin_lock(&minors_lock);
 335                 hidraw_table[minor] = NULL;
 336                 spin_unlock(&minors_lock);
 337                 result = PTR_ERR(dev->dev);
 338                 kfree(dev);
 339                 goto out;
 340         }
 341
 342         init_waitqueue_head(&dev->wait);
 343         INIT_LIST_HEAD(&dev->list);
 344
 345         dev->hid = hid;
 346         dev->minor = minor;
 347
 348         dev->exist = 1;
 349         hid->hidraw = dev;
 350
 351 out:
 352         return result;
 353
 354 }
 355 EXPORT_SYMBOL_GPL(hidraw_connect);
 356
 357 void hidraw_disconnect(struct hid_device *hid)
 358 {
 359         struct hidraw *hidraw = hid->hidraw;
 360
 361         hidraw->exist = 0;
 362
 363         spin_lock(&minors_lock);
 364         hidraw_table[hidraw->minor] = NULL;
 365         spin_unlock(&minors_lock);
 366
 367         device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor));
 368
 369         if (hidraw->open) {
 370                 hid->hid_close(hid);
 371                 wake_up_interruptible(&hidraw->wait);
 372         } else {
 373                 kfree(hidraw);
 374         }
 375 }
 376 EXPORT_SYMBOL_GPL(hidraw_disconnect);
 377
 378 int __init hidraw_init(void)
 379 {
 380         int result;
 381         dev_t dev_id;
 382
 383         result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
 384                         HIDRAW_MAX_DEVICES, "hidraw");
 385
 386         hidraw_major = MAJOR(dev_id);
 387
 388         if (result < 0) {
 389                 printk(KERN_WARNING "hidraw: can't get major number\n");
 390                 result = 0;
 391                 goto out;
 392         }
 393
 394         hidraw_class = class_create(THIS_MODULE, "hidraw");
 395         if (IS_ERR(hidraw_class)) {
 396                 result = PTR_ERR(hidraw_class);
 397                 unregister_chrdev(hidraw_major, "hidraw");
 398                 goto out;
 399         }
 400
 401         cdev_init(&hidraw_cdev, &hidraw_ops);
 402         cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
 403 out:
 404         return result;
 405 }
 406
 407 void __exit hidraw_exit(void)
 408 {
 409         dev_t dev_id = MKDEV(hidraw_major, 0);
 410
 411         cdev_del(&hidraw_cdev);
 412         class_destroy(hidraw_class);
 413         unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
 414
 415 }