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![Dean Camera](/assets/img/avatar_default.png)
Currently the hidraw module can only read and write feature HID reports on demand, via dedicated ioctls. Input reports are read from the device through the read() interface, while output reports are written through the write interface(). This is insufficient; it is desirable in many situations to be able to read and write input and output reports through the control interface to cover additional scenarios: - Reading an input report by its report ID, to get initial state - Writing an input report, to set initial input state in the device - Reading an output report by its report ID, to obtain current state - Writing an output report by its report ID, out of band This patch adds these missing ioctl requests to read and write the remaining HID report types. Note that not all HID backends will neccesarily support this (e.g. while the USB link layer supports setting Input reports, others may not). Also included are documentation and example updates. The current hidraw documentation states that feature reports read from the device does *not* include the report ID, however this is not the case and the returned report will have its report ID prepended by conforming HID devices, as the report data sent from the device over the control endpoint must be indentical in format to those sent over the regular transport. Signed-off-by: Dean Camera <dean@fourwalledcubicle.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
649 lines
14 KiB
C
649 lines
14 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* HID raw devices, giving access to raw HID events.
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*
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* In comparison to hiddev, this device does not process the
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* hid events at all (no parsing, no lookups). This lets applications
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* to work on raw hid events as they want to, and avoids a need to
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* use a transport-specific userspace libhid/libusb libraries.
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*
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* Copyright (c) 2007-2014 Jiri Kosina
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/fs.h>
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/cdev.h>
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#include <linux/poll.h>
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#include <linux/device.h>
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#include <linux/major.h>
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#include <linux/slab.h>
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#include <linux/hid.h>
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#include <linux/mutex.h>
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#include <linux/sched/signal.h>
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#include <linux/string.h>
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#include <linux/hidraw.h>
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static int hidraw_major;
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static struct cdev hidraw_cdev;
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static struct class *hidraw_class;
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static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES];
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static DEFINE_MUTEX(minors_lock);
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static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
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{
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struct hidraw_list *list = file->private_data;
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int ret = 0, len;
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DECLARE_WAITQUEUE(wait, current);
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mutex_lock(&list->read_mutex);
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while (ret == 0) {
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if (list->head == list->tail) {
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add_wait_queue(&list->hidraw->wait, &wait);
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set_current_state(TASK_INTERRUPTIBLE);
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while (list->head == list->tail) {
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if (signal_pending(current)) {
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ret = -ERESTARTSYS;
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break;
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}
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if (!list->hidraw->exist) {
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ret = -EIO;
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break;
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}
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if (file->f_flags & O_NONBLOCK) {
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ret = -EAGAIN;
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break;
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}
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/* allow O_NONBLOCK to work well from other threads */
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mutex_unlock(&list->read_mutex);
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schedule();
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mutex_lock(&list->read_mutex);
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set_current_state(TASK_INTERRUPTIBLE);
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}
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set_current_state(TASK_RUNNING);
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remove_wait_queue(&list->hidraw->wait, &wait);
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}
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if (ret)
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goto out;
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len = list->buffer[list->tail].len > count ?
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count : list->buffer[list->tail].len;
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if (list->buffer[list->tail].value) {
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if (copy_to_user(buffer, list->buffer[list->tail].value, len)) {
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ret = -EFAULT;
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goto out;
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}
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ret = len;
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}
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kfree(list->buffer[list->tail].value);
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list->buffer[list->tail].value = NULL;
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list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1);
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}
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out:
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mutex_unlock(&list->read_mutex);
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return ret;
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}
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/*
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* The first byte of the report buffer is expected to be a report number.
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*/
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static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
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{
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unsigned int minor = iminor(file_inode(file));
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struct hid_device *dev;
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__u8 *buf;
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int ret = 0;
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lockdep_assert_held(&minors_lock);
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if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
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ret = -ENODEV;
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goto out;
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}
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dev = hidraw_table[minor]->hid;
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if (count > HID_MAX_BUFFER_SIZE) {
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hid_warn(dev, "pid %d passed too large report\n",
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task_pid_nr(current));
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ret = -EINVAL;
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goto out;
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}
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if (count < 2) {
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hid_warn(dev, "pid %d passed too short report\n",
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task_pid_nr(current));
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ret = -EINVAL;
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goto out;
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}
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buf = memdup_user(buffer, count);
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if (IS_ERR(buf)) {
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ret = PTR_ERR(buf);
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goto out;
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}
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if ((report_type == HID_OUTPUT_REPORT) &&
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!(dev->quirks & HID_QUIRK_NO_OUTPUT_REPORTS_ON_INTR_EP)) {
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ret = hid_hw_output_report(dev, buf, count);
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/*
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* compatibility with old implementation of USB-HID and I2C-HID:
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* if the device does not support receiving output reports,
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* on an interrupt endpoint, fallback to SET_REPORT HID command.
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*/
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if (ret != -ENOSYS)
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goto out_free;
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}
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ret = hid_hw_raw_request(dev, buf[0], buf, count, report_type,
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HID_REQ_SET_REPORT);
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out_free:
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kfree(buf);
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out:
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return ret;
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}
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static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
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{
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ssize_t ret;
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mutex_lock(&minors_lock);
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ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
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mutex_unlock(&minors_lock);
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return ret;
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}
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/*
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* This function performs a Get_Report transfer over the control endpoint
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* per section 7.2.1 of the HID specification, version 1.1. The first byte
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* of buffer is the report number to request, or 0x0 if the device does not
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* use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
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* or HID_INPUT_REPORT.
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*/
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static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
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{
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unsigned int minor = iminor(file_inode(file));
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struct hid_device *dev;
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__u8 *buf;
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int ret = 0, len;
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unsigned char report_number;
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lockdep_assert_held(&minors_lock);
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if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
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ret = -ENODEV;
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goto out;
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}
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dev = hidraw_table[minor]->hid;
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if (!dev->ll_driver->raw_request) {
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ret = -ENODEV;
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goto out;
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}
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if (count > HID_MAX_BUFFER_SIZE) {
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hid_warn(dev, "pid %d passed too large report\n",
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task_pid_nr(current));
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ret = -EINVAL;
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goto out;
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}
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if (count < 2) {
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hid_warn(dev, "pid %d passed too short report\n",
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task_pid_nr(current));
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ret = -EINVAL;
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goto out;
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}
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buf = kmalloc(count, GFP_KERNEL);
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if (!buf) {
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ret = -ENOMEM;
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goto out;
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}
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/*
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* Read the first byte from the user. This is the report number,
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* which is passed to hid_hw_raw_request().
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*/
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if (copy_from_user(&report_number, buffer, 1)) {
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ret = -EFAULT;
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goto out_free;
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}
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ret = hid_hw_raw_request(dev, report_number, buf, count, report_type,
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HID_REQ_GET_REPORT);
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if (ret < 0)
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goto out_free;
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len = (ret < count) ? ret : count;
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if (copy_to_user(buffer, buf, len)) {
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ret = -EFAULT;
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goto out_free;
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}
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ret = len;
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out_free:
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kfree(buf);
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out:
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return ret;
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}
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static __poll_t hidraw_poll(struct file *file, poll_table *wait)
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{
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struct hidraw_list *list = file->private_data;
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__poll_t mask = EPOLLOUT | EPOLLWRNORM; /* hidraw is always writable */
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poll_wait(file, &list->hidraw->wait, wait);
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if (list->head != list->tail)
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mask |= EPOLLIN | EPOLLRDNORM;
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if (!list->hidraw->exist)
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mask |= EPOLLERR | EPOLLHUP;
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return mask;
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}
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static int hidraw_open(struct inode *inode, struct file *file)
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{
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unsigned int minor = iminor(inode);
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struct hidraw *dev;
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struct hidraw_list *list;
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unsigned long flags;
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int err = 0;
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if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) {
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err = -ENOMEM;
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goto out;
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}
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mutex_lock(&minors_lock);
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if (!hidraw_table[minor] || !hidraw_table[minor]->exist) {
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err = -ENODEV;
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goto out_unlock;
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}
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dev = hidraw_table[minor];
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if (!dev->open++) {
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err = hid_hw_power(dev->hid, PM_HINT_FULLON);
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if (err < 0) {
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dev->open--;
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goto out_unlock;
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}
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err = hid_hw_open(dev->hid);
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if (err < 0) {
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hid_hw_power(dev->hid, PM_HINT_NORMAL);
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dev->open--;
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goto out_unlock;
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}
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}
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list->hidraw = hidraw_table[minor];
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mutex_init(&list->read_mutex);
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spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
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list_add_tail(&list->node, &hidraw_table[minor]->list);
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spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
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file->private_data = list;
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out_unlock:
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mutex_unlock(&minors_lock);
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out:
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if (err < 0)
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kfree(list);
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return err;
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}
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static int hidraw_fasync(int fd, struct file *file, int on)
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{
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struct hidraw_list *list = file->private_data;
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return fasync_helper(fd, file, on, &list->fasync);
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}
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static void drop_ref(struct hidraw *hidraw, int exists_bit)
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{
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if (exists_bit) {
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hidraw->exist = 0;
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if (hidraw->open) {
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hid_hw_close(hidraw->hid);
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wake_up_interruptible(&hidraw->wait);
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}
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device_destroy(hidraw_class,
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MKDEV(hidraw_major, hidraw->minor));
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} else {
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--hidraw->open;
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}
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if (!hidraw->open) {
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if (!hidraw->exist) {
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hidraw_table[hidraw->minor] = NULL;
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kfree(hidraw);
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} else {
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/* close device for last reader */
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hid_hw_close(hidraw->hid);
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hid_hw_power(hidraw->hid, PM_HINT_NORMAL);
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}
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}
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}
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static int hidraw_release(struct inode * inode, struct file * file)
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{
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unsigned int minor = iminor(inode);
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struct hidraw_list *list = file->private_data;
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unsigned long flags;
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mutex_lock(&minors_lock);
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spin_lock_irqsave(&hidraw_table[minor]->list_lock, flags);
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list_del(&list->node);
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spin_unlock_irqrestore(&hidraw_table[minor]->list_lock, flags);
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kfree(list);
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drop_ref(hidraw_table[minor], 0);
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mutex_unlock(&minors_lock);
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return 0;
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}
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static long hidraw_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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{
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struct inode *inode = file_inode(file);
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unsigned int minor = iminor(inode);
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long ret = 0;
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struct hidraw *dev;
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void __user *user_arg = (void __user*) arg;
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mutex_lock(&minors_lock);
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dev = hidraw_table[minor];
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if (!dev || !dev->exist) {
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ret = -ENODEV;
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goto out;
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}
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switch (cmd) {
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case HIDIOCGRDESCSIZE:
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if (put_user(dev->hid->rsize, (int __user *)arg))
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ret = -EFAULT;
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break;
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case HIDIOCGRDESC:
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{
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__u32 len;
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if (get_user(len, (int __user *)arg))
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ret = -EFAULT;
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else if (len > HID_MAX_DESCRIPTOR_SIZE - 1)
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ret = -EINVAL;
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else if (copy_to_user(user_arg + offsetof(
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struct hidraw_report_descriptor,
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value[0]),
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dev->hid->rdesc,
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min(dev->hid->rsize, len)))
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ret = -EFAULT;
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break;
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}
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case HIDIOCGRAWINFO:
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{
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struct hidraw_devinfo dinfo;
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dinfo.bustype = dev->hid->bus;
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dinfo.vendor = dev->hid->vendor;
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dinfo.product = dev->hid->product;
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if (copy_to_user(user_arg, &dinfo, sizeof(dinfo)))
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ret = -EFAULT;
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break;
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}
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default:
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{
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struct hid_device *hid = dev->hid;
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if (_IOC_TYPE(cmd) != 'H') {
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ret = -EINVAL;
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
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int len = _IOC_SIZE(cmd);
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ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
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int len = _IOC_SIZE(cmd);
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ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSINPUT(0))) {
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int len = _IOC_SIZE(cmd);
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ret = hidraw_send_report(file, user_arg, len, HID_INPUT_REPORT);
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGINPUT(0))) {
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int len = _IOC_SIZE(cmd);
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ret = hidraw_get_report(file, user_arg, len, HID_INPUT_REPORT);
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSOUTPUT(0))) {
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int len = _IOC_SIZE(cmd);
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ret = hidraw_send_report(file, user_arg, len, HID_OUTPUT_REPORT);
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGOUTPUT(0))) {
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int len = _IOC_SIZE(cmd);
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ret = hidraw_get_report(file, user_arg, len, HID_OUTPUT_REPORT);
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break;
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}
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/* Begin Read-only ioctls. */
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if (_IOC_DIR(cmd) != _IOC_READ) {
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ret = -EINVAL;
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWNAME(0))) {
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int len = strlen(hid->name) + 1;
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if (len > _IOC_SIZE(cmd))
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len = _IOC_SIZE(cmd);
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ret = copy_to_user(user_arg, hid->name, len) ?
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-EFAULT : len;
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWPHYS(0))) {
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int len = strlen(hid->phys) + 1;
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if (len > _IOC_SIZE(cmd))
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len = _IOC_SIZE(cmd);
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ret = copy_to_user(user_arg, hid->phys, len) ?
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-EFAULT : len;
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break;
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}
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if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGRAWUNIQ(0))) {
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int len = strlen(hid->uniq) + 1;
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if (len > _IOC_SIZE(cmd))
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len = _IOC_SIZE(cmd);
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ret = copy_to_user(user_arg, hid->uniq, len) ?
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-EFAULT : len;
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break;
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}
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}
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ret = -ENOTTY;
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}
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out:
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mutex_unlock(&minors_lock);
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return ret;
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}
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static const struct file_operations hidraw_ops = {
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.owner = THIS_MODULE,
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.read = hidraw_read,
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.write = hidraw_write,
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.poll = hidraw_poll,
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.open = hidraw_open,
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.release = hidraw_release,
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.unlocked_ioctl = hidraw_ioctl,
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.fasync = hidraw_fasync,
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.compat_ioctl = compat_ptr_ioctl,
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.llseek = noop_llseek,
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};
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|
int hidraw_report_event(struct hid_device *hid, u8 *data, int len)
|
|
{
|
|
struct hidraw *dev = hid->hidraw;
|
|
struct hidraw_list *list;
|
|
int ret = 0;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&dev->list_lock, flags);
|
|
list_for_each_entry(list, &dev->list, node) {
|
|
int new_head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1);
|
|
|
|
if (new_head == list->tail)
|
|
continue;
|
|
|
|
if (!(list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC))) {
|
|
ret = -ENOMEM;
|
|
break;
|
|
}
|
|
list->buffer[list->head].len = len;
|
|
list->head = new_head;
|
|
kill_fasync(&list->fasync, SIGIO, POLL_IN);
|
|
}
|
|
spin_unlock_irqrestore(&dev->list_lock, flags);
|
|
|
|
wake_up_interruptible(&dev->wait);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(hidraw_report_event);
|
|
|
|
int hidraw_connect(struct hid_device *hid)
|
|
{
|
|
int minor, result;
|
|
struct hidraw *dev;
|
|
|
|
/* we accept any HID device, all applications */
|
|
|
|
dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL);
|
|
if (!dev)
|
|
return -ENOMEM;
|
|
|
|
result = -EINVAL;
|
|
|
|
mutex_lock(&minors_lock);
|
|
|
|
for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) {
|
|
if (hidraw_table[minor])
|
|
continue;
|
|
hidraw_table[minor] = dev;
|
|
result = 0;
|
|
break;
|
|
}
|
|
|
|
if (result) {
|
|
mutex_unlock(&minors_lock);
|
|
kfree(dev);
|
|
goto out;
|
|
}
|
|
|
|
dev->dev = device_create(hidraw_class, &hid->dev, MKDEV(hidraw_major, minor),
|
|
NULL, "%s%d", "hidraw", minor);
|
|
|
|
if (IS_ERR(dev->dev)) {
|
|
hidraw_table[minor] = NULL;
|
|
mutex_unlock(&minors_lock);
|
|
result = PTR_ERR(dev->dev);
|
|
kfree(dev);
|
|
goto out;
|
|
}
|
|
|
|
init_waitqueue_head(&dev->wait);
|
|
spin_lock_init(&dev->list_lock);
|
|
INIT_LIST_HEAD(&dev->list);
|
|
|
|
dev->hid = hid;
|
|
dev->minor = minor;
|
|
|
|
dev->exist = 1;
|
|
hid->hidraw = dev;
|
|
|
|
mutex_unlock(&minors_lock);
|
|
out:
|
|
return result;
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(hidraw_connect);
|
|
|
|
void hidraw_disconnect(struct hid_device *hid)
|
|
{
|
|
struct hidraw *hidraw = hid->hidraw;
|
|
|
|
mutex_lock(&minors_lock);
|
|
|
|
drop_ref(hidraw, 1);
|
|
|
|
mutex_unlock(&minors_lock);
|
|
}
|
|
EXPORT_SYMBOL_GPL(hidraw_disconnect);
|
|
|
|
int __init hidraw_init(void)
|
|
{
|
|
int result;
|
|
dev_t dev_id;
|
|
|
|
result = alloc_chrdev_region(&dev_id, HIDRAW_FIRST_MINOR,
|
|
HIDRAW_MAX_DEVICES, "hidraw");
|
|
if (result < 0) {
|
|
pr_warn("can't get major number\n");
|
|
goto out;
|
|
}
|
|
|
|
hidraw_major = MAJOR(dev_id);
|
|
|
|
hidraw_class = class_create(THIS_MODULE, "hidraw");
|
|
if (IS_ERR(hidraw_class)) {
|
|
result = PTR_ERR(hidraw_class);
|
|
goto error_cdev;
|
|
}
|
|
|
|
cdev_init(&hidraw_cdev, &hidraw_ops);
|
|
result = cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES);
|
|
if (result < 0)
|
|
goto error_class;
|
|
|
|
pr_info("raw HID events driver (C) Jiri Kosina\n");
|
|
out:
|
|
return result;
|
|
|
|
error_class:
|
|
class_destroy(hidraw_class);
|
|
error_cdev:
|
|
unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
|
|
goto out;
|
|
}
|
|
|
|
void hidraw_exit(void)
|
|
{
|
|
dev_t dev_id = MKDEV(hidraw_major, 0);
|
|
|
|
cdev_del(&hidraw_cdev);
|
|
class_destroy(hidraw_class);
|
|
unregister_chrdev_region(dev_id, HIDRAW_MAX_DEVICES);
|
|
|
|
}
|