/* * HID raw devices, giving access to raw HID events. * * In comparison to hiddev, this device does not process the * hid events at all (no parsing, no lookups). This lets applications * to work on raw hid events as they want to, and avoids a need to * use a transport-specific userspace libhid/libusb libraries. * * Copyright (c) 2007 Jiri Kosina */ /* * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * You should have received a copy of the GNU General Public License along with * this program; if not, write to the Free Software Foundation, Inc., * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. */ #include <linux/fs.h> #include <linux/module.h> #include <linux/errno.h> #include <linux/kernel.h> #include <linux/init.h> #include <linux/cdev.h> #include <linux/poll.h> #include <linux/device.h> #include <linux/major.h> #include <linux/hid.h> #include <linux/mutex.h> #include <linux/hidraw.h> static int hidraw_major; static struct cdev hidraw_cdev; static struct class *hidraw_class; static struct hidraw *hidraw_table[HIDRAW_MAX_DEVICES]; static DEFINE_SPINLOCK(minors_lock); static ssize_t hidraw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos) { struct hidraw_list *list = file->private_data; int ret = 0, len; char *report; DECLARE_WAITQUEUE(wait, current); while (ret == 0) { mutex_lock(&list->read_mutex); if (list->head == list->tail) { add_wait_queue(&list->hidraw->wait, &wait); set_current_state(TASK_INTERRUPTIBLE); while (list->head == list->tail) { if (file->f_flags & O_NONBLOCK) { ret = -EAGAIN; break; } if (signal_pending(current)) { ret = -ERESTARTSYS; break; } if (!list->hidraw->exist) { ret = -EIO; break; } /* allow O_NONBLOCK to work well from other threads */ mutex_unlock(&list->read_mutex); schedule(); mutex_lock(&list->read_mutex); set_current_state(TASK_INTERRUPTIBLE); } set_current_state(TASK_RUNNING); remove_wait_queue(&list->hidraw->wait, &wait); } if (ret) goto out; report = list->buffer[list->tail].value; len = list->buffer[list->tail].len > count ? count : list->buffer[list->tail].len; if (copy_to_user(buffer, list->buffer[list->tail].value, len)) { ret = -EFAULT; goto out; } ret += len; kfree(list->buffer[list->tail].value); list->tail = (list->tail + 1) & (HIDRAW_BUFFER_SIZE - 1); } out: mutex_unlock(&list->read_mutex); return ret; } /* the first byte is expected to be a report number */ static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos) { unsigned int minor = iminor(file->f_path.dentry->d_inode); struct hid_device *dev = hidraw_table[minor]->hid; __u8 *buf; int ret = 0; if (!dev->hid_output_raw_report) return -ENODEV; if (count > HID_MIN_BUFFER_SIZE) { printk(KERN_WARNING "hidraw: pid %d passed too large report\n", task_pid_nr(current)); return -EINVAL; } if (count < 2) { printk(KERN_WARNING "hidraw: pid %d passed too short report\n", task_pid_nr(current)); return -EINVAL; } buf = kmalloc(count * sizeof(__u8), GFP_KERNEL); if (!buf) return -ENOMEM; if (copy_from_user(buf, buffer, count)) { ret = -EFAULT; goto out; } ret = dev->hid_output_raw_report(dev, buf, count); out: kfree(buf); return ret; } static unsigned int hidraw_poll(struct file *file, poll_table *wait) { struct hidraw_list *list = file->private_data; poll_wait(file, &list->hidraw->wait, wait); if (list->head != list->tail) return POLLIN | POLLRDNORM; if (!list->hidraw->exist) return POLLERR | POLLHUP; return 0; } static int hidraw_open(struct inode *inode, struct file *file) { unsigned int minor = iminor(inode); struct hidraw *dev; struct hidraw_list *list; int err = 0; if (!(list = kzalloc(sizeof(struct hidraw_list), GFP_KERNEL))) { err = -ENOMEM; goto out; } spin_lock(&minors_lock); if (!hidraw_table[minor]) { printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n", minor); kfree(list); err = -ENODEV; goto out_unlock; } list->hidraw = hidraw_table[minor]; mutex_init(&list->read_mutex); list_add_tail(&list->node, &hidraw_table[minor]->list); file->private_data = list; dev = hidraw_table[minor]; if (!dev->open++) dev->hid->hid_open(dev->hid); out_unlock: spin_unlock(&minors_lock); out: return err; } static int hidraw_release(struct inode * inode, struct file * file) { unsigned int minor = iminor(inode); struct hidraw *dev; struct hidraw_list *list = file->private_data; if (!hidraw_table[minor]) { printk(KERN_EMERG "hidraw device with minor %d doesn't exist\n", minor); return -ENODEV; } list_del(&list->node); dev = hidraw_table[minor]; if (!dev->open--) { if (list->hidraw->exist) dev->hid->hid_close(dev->hid); else kfree(list->hidraw); } return 0; } static int hidraw_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { unsigned int minor = iminor(inode); struct hidraw *dev = hidraw_table[minor]; void __user *user_arg = (void __user*) arg; switch (cmd) { case HIDIOCGRDESCSIZE: if (put_user(dev->hid->rsize, (int __user *)arg)) return -EFAULT; return 0; case HIDIOCGRDESC: { __u32 len; if (get_user(len, (int __user *)arg)) return -EFAULT; if (len > HID_MAX_DESCRIPTOR_SIZE - 1) return -EINVAL; if (copy_to_user(user_arg + offsetof( struct hidraw_report_descriptor, value[0]), dev->hid->rdesc, min(dev->hid->rsize, len))) return -EFAULT; return 0; } case HIDIOCGRAWINFO: { struct hidraw_devinfo dinfo; dinfo.bustype = dev->hid->bus; dinfo.vendor = dev->hid->vendor; dinfo.product = dev->hid->product; if (copy_to_user(user_arg, &dinfo, sizeof(dinfo))) return -EFAULT; return 0; } default: printk(KERN_EMERG "hidraw: unsupported ioctl() %x\n", cmd); } return -EINVAL; } static const struct file_operations hidraw_ops = { .owner = THIS_MODULE, .read = hidraw_read, .write = hidraw_write, .poll = hidraw_poll, .open = hidraw_open, .release = hidraw_release, .ioctl = hidraw_ioctl, }; void hidraw_report_event(struct hid_device *hid, u8 *data, int len) { struct hidraw *dev = hid->hidraw; struct hidraw_list *list; list_for_each_entry(list, &dev->list, node) { list->buffer[list->head].value = kmemdup(data, len, GFP_ATOMIC); list->buffer[list->head].len = len; list->head = (list->head + 1) & (HIDRAW_BUFFER_SIZE - 1); kill_fasync(&list->fasync, SIGIO, POLL_IN); } wake_up_interruptible(&dev->wait); } EXPORT_SYMBOL_GPL(hidraw_report_event); int hidraw_connect(struct hid_device *hid) { int minor, result; struct hidraw *dev; /* TODO currently we accept any HID device. This should later * probably be fixed to accept only those devices which provide * non-input applications */ dev = kzalloc(sizeof(struct hidraw), GFP_KERNEL); if (!dev) return -ENOMEM; result = -EINVAL; spin_lock(&minors_lock); for (minor = 0; minor < HIDRAW_MAX_DEVICES; minor++) { if (hidraw_table[minor]) continue; hidraw_table[minor] = dev; result = 0; break; } spin_unlock(&minors_lock); if (result) { kfree(dev); goto out; } dev->dev = device_create(hidraw_class, NULL, MKDEV(hidraw_major, minor), "%s%d", "hidraw", minor); if (IS_ERR(dev->dev)) { spin_lock(&minors_lock); hidraw_table[minor] = NULL; spin_unlock(&minors_lock); result = PTR_ERR(dev->dev); kfree(dev); goto out; } init_waitqueue_head(&dev->wait); INIT_LIST_HEAD(&dev->list); dev->hid = hid; dev->minor = minor; dev->exist = 1; hid->hidraw = dev; out: return result; } EXPORT_SYMBOL_GPL(hidraw_connect); void hidraw_disconnect(struct hid_device *hid) { struct hidraw *hidraw = hid->hidraw; hidraw->exist = 0; spin_lock(&minors_lock); hidraw_table[hidraw->minor] = NULL; spin_unlock(&minors_lock); device_destroy(hidraw_class, MKDEV(hidraw_major, hidraw->minor)); if (hidraw->open) { hid->hid_close(hid); wake_up_interruptible(&hidraw->wait); } else { kfree(hidraw); } } 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"); hidraw_major = MAJOR(dev_id); if (result < 0) { printk(KERN_WARNING "hidraw: can't get major number\n"); result = 0; goto out; } hidraw_class = class_create(THIS_MODULE, "hidraw"); if (IS_ERR(hidraw_class)) { result = PTR_ERR(hidraw_class); unregister_chrdev(hidraw_major, "hidraw"); goto out; } cdev_init(&hidraw_cdev, &hidraw_ops); cdev_add(&hidraw_cdev, dev_id, HIDRAW_MAX_DEVICES); out: return result; } void __exit 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); }