1 // SPDX-License-Identifier: GPL-2.0-only
3 * HID raw devices, giving access to raw HID events.
5 * In comparison to hiddev, this device does not process the
6 * hid events at all (no parsing, no lookups). This lets applications
7 * to work on raw hid events as they want to, and avoids a need to
8 * use a transport-specific userspace libhid/libusb libraries.
10 * Copyright (c) 2007-2014 Jiri Kosina
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17 #include <linux/module.h>
18 #include <linux/errno.h>
19 #include <linux/kernel.h>
20 #include <linux/init.h>
21 #include <linux/cdev.h>
22 #include <linux/poll.h>
23 #include <linux/device.h>
24 #include <linux/major.h>
25 #include <linux/slab.h>
26 #include <linux/hid.h>
27 #include <linux/mutex.h>
28 #include <linux/sched/signal.h>
29 #include <linux/string.h>
31 #include <linux/hidraw.h>
33 static int hidraw_major;
34 static struct cdev hidraw_cdev;
35 static struct class *hidraw_class;
36 static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
37 static DEFINE_MUTEX(minors_lock);
39 static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
41 struct hidraw_list *list = file->private_data;
43 DECLARE_WAITQUEUE(wait, current);
45 mutex_lock(&list->read_mutex);
48 if (list->head == list->tail) {
49 add_wait_queue(&list->hidraw->wait, &wait);
50 set_current_state(TASK_INTERRUPTIBLE);
52 while (list->head == list->tail) {
53 if (signal_pending(current)) {
57 if (!list->hidraw->exist) {
61 if (file->f_flags & O_NONBLOCK) {
66 /* allow O_NONBLOCK to work well from other threads */
67 mutex_unlock(&list->read_mutex);
69 mutex_lock(&list->read_mutex);
70 set_current_state(TASK_INTERRUPTIBLE);
73 set_current_state(TASK_RUNNING);
74 remove_wait_queue(&list->hidraw->wait, &wait);
80 len = list->buffer[list->tail].len > count ?
81 count : list->buffer[list->tail].len;
83 if (list->buffer[list->tail].value) {
84 if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
91 kfree(list->buffer[list->tail].value);
92 list->buffer[list->tail].value = NULL;
93 list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
96 mutex_unlock(&list->read_mutex);
101 * The first byte of the report buffer is expected to be a report number.
103 static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
105 unsigned int minor = iminor(file_inode(file));
106 struct hid_device *dev;
110 lockdep_assert_held(&minors_lock);
112 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
117 dev = hidraw_table[minor]->hid;
119 if (count > HID_MAX_BUFFER_SIZE) {
120 hid_warn(dev, "pid %d passed too large report\n",
121 task_pid_nr(current));
127 hid_warn(dev, "pid %d passed too short report\n",
128 task_pid_nr(current));
133 buf = memdup_user(buffer, count);
139 if ((report_type == HID_OUTPUT_REPORT) &&
140 !(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
141 ret = hid_hw_output_report(dev, buf, count);
143 * compatibility with old implementation of USB-HID and I2C-HID:
144 * if the device does not support receiving output reports,
145 * on an interrupt endpoint, fallback to SET_REPORT HID command.
151 ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
160 static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
163 mutex_lock(&minors_lock);
164 ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
165 mutex_unlock(&minors_lock);
171 * This function performs a Get_Report transfer over the control endpoint
172 * per section 7.2.1 of the HID specification, version 1.1. The first byte
173 * of buffer is the report number to request, or 0x0 if the defice does not
174 * use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
175 * or HID_INPUT_REPORT.
177 static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
179 unsigned int minor = iminor(file_inode(file));
180 struct hid_device *dev;
183 unsigned char report_number;
185 lockdep_assert_held(&minors_lock);
187 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
192 dev = hidraw_table[minor]->hid;
194 if (!dev->ll_driver->raw_request) {
199 if (count > HID_MAX_BUFFER_SIZE) {
200 printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
201 task_pid_nr(current));
207 printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
208 task_pid_nr(current));
213 buf = kmalloc(count, GFP_KERNEL);
220 * Read the first byte from the user. This is the report number,
221 * which is passed to hid_hw_raw_request().
223 if (copy_from_user(&report_number, buffer, 1)) {
228 ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
234 len = (ret < count) ? ret : count;
236 if (copy_to_user(buffer, buf, len)) {
249 static __poll_t hidraw_poll(struct file *file, poll_table *wait)
251 struct hidraw_list *list = file->private_data;
253 poll_wait(file, &list->hidraw->wait, wait);
254 if (list->head != list->tail)
255 return EPOLLIN | EPOLLRDNORM;
256 if (!list->hidraw->exist)
257 return EPOLLERR | EPOLLHUP;
261 static int hidraw_open(struct inode *inode, struct file *file)
263 unsigned int minor = iminor(inode);
265 struct hidraw_list *list;
269 if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
274 mutex_lock(&minors_lock);
275 if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
280 dev = hidraw_table[minor];
282 err = hid_hw_power(dev->hid, PM_HINT_FULLON);
288 err = hid_hw_open(dev->hid);
290 hid_hw_power(dev->hid, PM_HINT_NORMAL);
296 list->hidraw = hidraw_table[minor];
297 mutex_init(&list->read_mutex);
298 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
299 list_add_tail(&list->node, &hidraw_table[minor]->list);
300 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
301 file->private_data = list;
303 mutex_unlock(&minors_lock);
311 static int hidraw_fasync(int fd, struct file *file, int on)
313 struct hidraw_list *list = file->private_data;
315 return fasync_helper(fd, file, on, &list->fasync);
318 static void drop_ref(struct hidraw *hidraw, int exists_bit)
323 hid_hw_close(hidraw->hid);
324 wake_up_interruptible(&hidraw->wait);
326 device_destroy(hidraw_class,
327 MKDEV(hidraw_major, hidraw->minor));
332 if (!hidraw->exist) {
333 hidraw_table[hidraw->minor] = NULL;
336 /* close device for last reader */
337 hid_hw_close(hidraw->hid);
338 hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
343 static int hidraw_release(struct inode * inode, struct file * file)
345 unsigned int minor = iminor(inode);
346 struct hidraw_list *list = file->private_data;
349 mutex_lock(&minors_lock);
351 spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
352 list_del(&list->node);
353 spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
356 drop_ref(hidraw_table[minor], 0);
358 mutex_unlock(&minors_lock);
362 static long hidraw_ioctl(struct file *file, unsigned int cmd,
365 struct inode *inode = file_inode(file);
366 unsigned int minor = iminor(inode);
369 void __user *user_arg = (void __user*) arg;
371 mutex_lock(&minors_lock);
372 dev = hidraw_table[minor];
379 case HIDIOCGRDESCSIZE:
380 if (put_user(dev->hid->rsize, (int __user *)arg))
388 if (get_user(len, (int __user *)arg))
390 else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
392 else if (copy_to_user(user_arg + offsetof(
393 struct hidraw_report_descriptor,
396 min(dev->hid->rsize, len)))
402 struct hidraw_devinfo dinfo;
404 dinfo.bustype = dev->hid->bus;
405 dinfo.vendor = dev->hid->vendor;
406 dinfo.product = dev->hid->product;
407 if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
413 struct hid_device *hid = dev->hid;
414 if (_IOC_TYPE(cmd) != 'H') {
419 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
420 int len = _IOC_SIZE(cmd);
421 ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
424 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
425 int len = _IOC_SIZE(cmd);
426 ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
430 /* Begin Read-only ioctls. */
431 if (_IOC_DIR(cmd) != _IOC_READ) {
436 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
437 int len = strlen(hid->name) + 1;
438 if (len > _IOC_SIZE(cmd))
439 len = _IOC_SIZE(cmd);
440 ret = copy_to_user(user_arg, hid->name, len) ?
445 if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
446 int len = strlen(hid->phys) + 1;
447 if (len > _IOC_SIZE(cmd))
448 len = _IOC_SIZE(cmd);
449 ret = copy_to_user(user_arg, hid->phys, len) ?
458 mutex_unlock(&minors_lock);
462 static const struct file_operations hidraw_ops = {
463 .owner = THIS_MODULE,
465 .write = hidraw_write,
468 .release = hidraw_release,
469 .unlocked_ioctl = hidraw_ioctl,
470 .fasync = hidraw_fasync,
472 .compat_ioctl = hidraw_ioctl,
474 .llseek = noop_llseek,
477 int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
479 struct hidraw *dev = hid->hidraw;
480 struct hidraw_list *list;
484 spin_lock_irqsave(&dev->list_lock, flags);
485 list_for_each_entry(list, &dev->list, node) {
486 int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
488 if (new_head == list->tail)
491 if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
495 list->buffer[list->head].len = len;
496 list->head = new_head;
497 kill_fasync(&list->fasync, SIGIO, POLL_IN);
499 spin_unlock_irqrestore(&dev->list_lock, flags);
501 wake_up_interruptible(&dev->wait);
504 EXPORT_SYMBOL_GPL(hidraw_report_event);
506 int hidraw_connect(struct hid_device *hid)
511 /* we accept any HID device, all applications */
513 dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
519 mutex_lock(&minors_lock);
521 for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
522 if (hidraw_table[minor])
524 hidraw_table[minor] = dev;
530 mutex_unlock(&minors_lock);
535 dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
536 NULL, "%s%d", "hidraw", minor);
538 if (IS_ERR(dev->dev)) {
539 hidraw_table[minor] = NULL;
540 mutex_unlock(&minors_lock);
541 result = PTR_ERR(dev->dev);
546 init_waitqueue_head(&dev->wait);
547 spin_lock_init(&dev->list_lock);
548 INIT_LIST_HEAD(&dev->list);
556 mutex_unlock(&minors_lock);
561 EXPORT_SYMBOL_GPL(hidraw_connect);
563 void hidraw_disconnect(struct hid_device *hid)
565 struct hidraw *hidraw = hid->hidraw;
567 mutex_lock(&minors_lock);
571 mutex_unlock(&minors_lock);
573 EXPORT_SYMBOL_GPL(hidraw_disconnect);
575 int __init hidraw_init(void)
580 result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
581 HIDRAW_MAX_DEVICES, "hidraw");
583 pr_warn("can't get major number\n");
587 hidraw_major = MAJOR(dev_id);
589 hidraw_class = class_create(THIS_MODULE, "hidraw");
590 if (IS_ERR(hidraw_class)) {
591 result = PTR_ERR(hidraw_class);
595 cdev_init(&hidraw_cdev, &hidraw_ops);
596 result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
600 printk(KERN_INFO "hidraw: raw HID events driver (C) Jiri Kosina\n");
605 class_destroy(hidraw_class);
607 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
611 void hidraw_exit(void)
613 dev_t dev_id = MKDEV(hidraw_major, 0);
615 cdev_del(&hidraw_cdev);
616 class_destroy(hidraw_class);
617 unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);