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![Jann Horn](/assets/img/avatar_default.png)
The flag uhid->running can be set to false by uhid_device_add_worker() without holding the uhid->devlock. Mark all reads/writes of the flag that might race with READ_ONCE()/WRITE_ONCE() for clarity and correctness. Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
821 lines
19 KiB
C
821 lines
19 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* User-space I/O driver support for HID subsystem
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* Copyright (c) 2012 David Herrmann
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*/
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/*
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*/
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#include <linux/atomic.h>
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#include <linux/compat.h>
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#include <linux/cred.h>
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#include <linux/device.h>
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#include <linux/fs.h>
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#include <linux/hid.h>
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#include <linux/input.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/poll.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/uhid.h>
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#include <linux/wait.h>
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#define UHID_NAME "uhid"
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#define UHID_BUFSIZE 32
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struct uhid_device {
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struct mutex devlock;
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/* This flag tracks whether the HID device is usable for commands from
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* userspace. The flag is already set before hid_add_device(), which
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* runs in workqueue context, to allow hid_add_device() to communicate
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* with userspace.
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* However, if hid_add_device() fails, the flag is cleared without
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* holding devlock.
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* We guarantee that if @running changes from true to false while you're
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* holding @devlock, it's still fine to access @hid.
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*/
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bool running;
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__u8 *rd_data;
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uint rd_size;
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/* When this is NULL, userspace may use UHID_CREATE/UHID_CREATE2. */
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struct hid_device *hid;
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struct uhid_event input_buf;
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wait_queue_head_t waitq;
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spinlock_t qlock;
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__u8 head;
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__u8 tail;
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struct uhid_event *outq[UHID_BUFSIZE];
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/* blocking GET_REPORT support; state changes protected by qlock */
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struct mutex report_lock;
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wait_queue_head_t report_wait;
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bool report_running;
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u32 report_id;
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u32 report_type;
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struct uhid_event report_buf;
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struct work_struct worker;
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};
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static struct miscdevice uhid_misc;
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static void uhid_device_add_worker(struct work_struct *work)
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{
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struct uhid_device *uhid = container_of(work, struct uhid_device, worker);
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int ret;
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ret = hid_add_device(uhid->hid);
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if (ret) {
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hid_err(uhid->hid, "Cannot register HID device: error %d\n", ret);
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/* We used to call hid_destroy_device() here, but that's really
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* messy to get right because we have to coordinate with
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* concurrent writes from userspace that might be in the middle
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* of using uhid->hid.
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* Just leave uhid->hid as-is for now, and clean it up when
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* userspace tries to close or reinitialize the uhid instance.
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*
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* However, we do have to clear the ->running flag and do a
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* wakeup to make sure userspace knows that the device is gone.
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*/
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WRITE_ONCE(uhid->running, false);
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wake_up_interruptible(&uhid->report_wait);
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}
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}
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static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
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{
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__u8 newhead;
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newhead = (uhid->head + 1) % UHID_BUFSIZE;
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if (newhead != uhid->tail) {
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uhid->outq[uhid->head] = ev;
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uhid->head = newhead;
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wake_up_interruptible(&uhid->waitq);
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} else {
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hid_warn(uhid->hid, "Output queue is full\n");
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kfree(ev);
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}
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}
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static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
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{
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unsigned long flags;
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struct uhid_event *ev;
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ev = kzalloc(sizeof(*ev), GFP_KERNEL);
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if (!ev)
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return -ENOMEM;
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ev->type = event;
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spin_lock_irqsave(&uhid->qlock, flags);
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uhid_queue(uhid, ev);
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spin_unlock_irqrestore(&uhid->qlock, flags);
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return 0;
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}
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static int uhid_hid_start(struct hid_device *hid)
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{
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struct uhid_device *uhid = hid->driver_data;
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struct uhid_event *ev;
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unsigned long flags;
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ev = kzalloc(sizeof(*ev), GFP_KERNEL);
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if (!ev)
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return -ENOMEM;
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ev->type = UHID_START;
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if (hid->report_enum[HID_FEATURE_REPORT].numbered)
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ev->u.start.dev_flags |= UHID_DEV_NUMBERED_FEATURE_REPORTS;
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if (hid->report_enum[HID_OUTPUT_REPORT].numbered)
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ev->u.start.dev_flags |= UHID_DEV_NUMBERED_OUTPUT_REPORTS;
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if (hid->report_enum[HID_INPUT_REPORT].numbered)
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ev->u.start.dev_flags |= UHID_DEV_NUMBERED_INPUT_REPORTS;
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spin_lock_irqsave(&uhid->qlock, flags);
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uhid_queue(uhid, ev);
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spin_unlock_irqrestore(&uhid->qlock, flags);
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return 0;
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}
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static void uhid_hid_stop(struct hid_device *hid)
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{
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struct uhid_device *uhid = hid->driver_data;
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hid->claimed = 0;
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uhid_queue_event(uhid, UHID_STOP);
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}
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static int uhid_hid_open(struct hid_device *hid)
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{
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struct uhid_device *uhid = hid->driver_data;
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return uhid_queue_event(uhid, UHID_OPEN);
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}
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static void uhid_hid_close(struct hid_device *hid)
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{
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struct uhid_device *uhid = hid->driver_data;
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uhid_queue_event(uhid, UHID_CLOSE);
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}
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static int uhid_hid_parse(struct hid_device *hid)
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{
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struct uhid_device *uhid = hid->driver_data;
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return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
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}
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/* must be called with report_lock held */
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static int __uhid_report_queue_and_wait(struct uhid_device *uhid,
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struct uhid_event *ev,
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__u32 *report_id)
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{
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unsigned long flags;
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int ret;
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spin_lock_irqsave(&uhid->qlock, flags);
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*report_id = ++uhid->report_id;
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uhid->report_type = ev->type + 1;
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uhid->report_running = true;
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uhid_queue(uhid, ev);
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spin_unlock_irqrestore(&uhid->qlock, flags);
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ret = wait_event_interruptible_timeout(uhid->report_wait,
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!uhid->report_running || !READ_ONCE(uhid->running),
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5 * HZ);
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if (!ret || !READ_ONCE(uhid->running) || uhid->report_running)
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ret = -EIO;
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else if (ret < 0)
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ret = -ERESTARTSYS;
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else
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ret = 0;
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uhid->report_running = false;
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return ret;
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}
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static void uhid_report_wake_up(struct uhid_device *uhid, u32 id,
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const struct uhid_event *ev)
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{
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unsigned long flags;
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spin_lock_irqsave(&uhid->qlock, flags);
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/* id for old report; drop it silently */
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if (uhid->report_type != ev->type || uhid->report_id != id)
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goto unlock;
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if (!uhid->report_running)
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goto unlock;
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memcpy(&uhid->report_buf, ev, sizeof(*ev));
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uhid->report_running = false;
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wake_up_interruptible(&uhid->report_wait);
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unlock:
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spin_unlock_irqrestore(&uhid->qlock, flags);
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}
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static int uhid_hid_get_report(struct hid_device *hid, unsigned char rnum,
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u8 *buf, size_t count, u8 rtype)
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{
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struct uhid_device *uhid = hid->driver_data;
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struct uhid_get_report_reply_req *req;
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struct uhid_event *ev;
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int ret;
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if (!READ_ONCE(uhid->running))
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return -EIO;
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ev = kzalloc(sizeof(*ev), GFP_KERNEL);
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if (!ev)
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return -ENOMEM;
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ev->type = UHID_GET_REPORT;
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ev->u.get_report.rnum = rnum;
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ev->u.get_report.rtype = rtype;
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ret = mutex_lock_interruptible(&uhid->report_lock);
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if (ret) {
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kfree(ev);
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return ret;
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}
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/* this _always_ takes ownership of @ev */
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ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.get_report.id);
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if (ret)
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goto unlock;
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req = &uhid->report_buf.u.get_report_reply;
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if (req->err) {
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ret = -EIO;
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} else {
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ret = min3(count, (size_t)req->size, (size_t)UHID_DATA_MAX);
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memcpy(buf, req->data, ret);
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}
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unlock:
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mutex_unlock(&uhid->report_lock);
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return ret;
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}
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static int uhid_hid_set_report(struct hid_device *hid, unsigned char rnum,
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const u8 *buf, size_t count, u8 rtype)
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{
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struct uhid_device *uhid = hid->driver_data;
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struct uhid_event *ev;
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int ret;
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if (!READ_ONCE(uhid->running) || count > UHID_DATA_MAX)
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return -EIO;
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ev = kzalloc(sizeof(*ev), GFP_KERNEL);
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if (!ev)
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return -ENOMEM;
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ev->type = UHID_SET_REPORT;
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ev->u.set_report.rnum = rnum;
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ev->u.set_report.rtype = rtype;
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ev->u.set_report.size = count;
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memcpy(ev->u.set_report.data, buf, count);
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ret = mutex_lock_interruptible(&uhid->report_lock);
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if (ret) {
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kfree(ev);
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return ret;
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}
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/* this _always_ takes ownership of @ev */
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ret = __uhid_report_queue_and_wait(uhid, ev, &ev->u.set_report.id);
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if (ret)
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goto unlock;
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if (uhid->report_buf.u.set_report_reply.err)
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ret = -EIO;
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else
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ret = count;
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unlock:
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mutex_unlock(&uhid->report_lock);
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return ret;
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}
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static int uhid_hid_raw_request(struct hid_device *hid, unsigned char reportnum,
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__u8 *buf, size_t len, unsigned char rtype,
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int reqtype)
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{
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u8 u_rtype;
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switch (rtype) {
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case HID_FEATURE_REPORT:
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u_rtype = UHID_FEATURE_REPORT;
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break;
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case HID_OUTPUT_REPORT:
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u_rtype = UHID_OUTPUT_REPORT;
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break;
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case HID_INPUT_REPORT:
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u_rtype = UHID_INPUT_REPORT;
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break;
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default:
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return -EINVAL;
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}
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switch (reqtype) {
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case HID_REQ_GET_REPORT:
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return uhid_hid_get_report(hid, reportnum, buf, len, u_rtype);
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case HID_REQ_SET_REPORT:
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return uhid_hid_set_report(hid, reportnum, buf, len, u_rtype);
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default:
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return -EIO;
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}
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}
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static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
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unsigned char report_type)
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{
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struct uhid_device *uhid = hid->driver_data;
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__u8 rtype;
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unsigned long flags;
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struct uhid_event *ev;
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switch (report_type) {
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case HID_FEATURE_REPORT:
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rtype = UHID_FEATURE_REPORT;
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break;
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case HID_OUTPUT_REPORT:
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rtype = UHID_OUTPUT_REPORT;
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break;
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default:
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return -EINVAL;
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}
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if (count < 1 || count > UHID_DATA_MAX)
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return -EINVAL;
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ev = kzalloc(sizeof(*ev), GFP_KERNEL);
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if (!ev)
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return -ENOMEM;
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ev->type = UHID_OUTPUT;
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ev->u.output.size = count;
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ev->u.output.rtype = rtype;
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memcpy(ev->u.output.data, buf, count);
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spin_lock_irqsave(&uhid->qlock, flags);
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uhid_queue(uhid, ev);
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spin_unlock_irqrestore(&uhid->qlock, flags);
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return count;
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}
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static int uhid_hid_output_report(struct hid_device *hid, __u8 *buf,
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size_t count)
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{
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return uhid_hid_output_raw(hid, buf, count, HID_OUTPUT_REPORT);
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}
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struct hid_ll_driver uhid_hid_driver = {
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.start = uhid_hid_start,
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.stop = uhid_hid_stop,
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.open = uhid_hid_open,
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.close = uhid_hid_close,
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.parse = uhid_hid_parse,
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.raw_request = uhid_hid_raw_request,
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.output_report = uhid_hid_output_report,
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};
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EXPORT_SYMBOL_GPL(uhid_hid_driver);
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#ifdef CONFIG_COMPAT
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/* Apparently we haven't stepped on these rakes enough times yet. */
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struct uhid_create_req_compat {
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__u8 name[128];
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__u8 phys[64];
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__u8 uniq[64];
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compat_uptr_t rd_data;
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__u16 rd_size;
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__u16 bus;
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__u32 vendor;
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__u32 product;
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__u32 version;
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__u32 country;
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} __attribute__((__packed__));
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static int uhid_event_from_user(const char __user *buffer, size_t len,
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struct uhid_event *event)
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{
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if (in_compat_syscall()) {
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u32 type;
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if (get_user(type, buffer))
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return -EFAULT;
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if (type == UHID_CREATE) {
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/*
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* This is our messed up request with compat pointer.
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* It is largish (more than 256 bytes) so we better
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* allocate it from the heap.
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*/
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struct uhid_create_req_compat *compat;
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compat = kzalloc(sizeof(*compat), GFP_KERNEL);
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if (!compat)
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return -ENOMEM;
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buffer += sizeof(type);
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len -= sizeof(type);
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if (copy_from_user(compat, buffer,
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min(len, sizeof(*compat)))) {
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kfree(compat);
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return -EFAULT;
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}
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/* Shuffle the data over to proper structure */
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event->type = type;
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memcpy(event->u.create.name, compat->name,
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sizeof(compat->name));
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memcpy(event->u.create.phys, compat->phys,
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sizeof(compat->phys));
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memcpy(event->u.create.uniq, compat->uniq,
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sizeof(compat->uniq));
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event->u.create.rd_data = compat_ptr(compat->rd_data);
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event->u.create.rd_size = compat->rd_size;
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event->u.create.bus = compat->bus;
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event->u.create.vendor = compat->vendor;
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event->u.create.product = compat->product;
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event->u.create.version = compat->version;
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event->u.create.country = compat->country;
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kfree(compat);
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return 0;
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}
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/* All others can be copied directly */
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}
|
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|
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if (copy_from_user(event, buffer, min(len, sizeof(*event))))
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return -EFAULT;
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|
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return 0;
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}
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#else
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static int uhid_event_from_user(const char __user *buffer, size_t len,
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struct uhid_event *event)
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{
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if (copy_from_user(event, buffer, min(len, sizeof(*event))))
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return -EFAULT;
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|
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return 0;
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}
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#endif
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|
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static int uhid_dev_create2(struct uhid_device *uhid,
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const struct uhid_event *ev)
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{
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struct hid_device *hid;
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size_t rd_size, len;
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void *rd_data;
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int ret;
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if (uhid->hid)
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return -EALREADY;
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rd_size = ev->u.create2.rd_size;
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if (rd_size <= 0 || rd_size > HID_MAX_DESCRIPTOR_SIZE)
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return -EINVAL;
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rd_data = kmemdup(ev->u.create2.rd_data, rd_size, GFP_KERNEL);
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if (!rd_data)
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return -ENOMEM;
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uhid->rd_size = rd_size;
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uhid->rd_data = rd_data;
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|
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hid = hid_allocate_device();
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if (IS_ERR(hid)) {
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ret = PTR_ERR(hid);
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goto err_free;
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}
|
|
|
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/* @hid is zero-initialized, strncpy() is correct, strlcpy() not */
|
|
len = min(sizeof(hid->name), sizeof(ev->u.create2.name)) - 1;
|
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strncpy(hid->name, ev->u.create2.name, len);
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len = min(sizeof(hid->phys), sizeof(ev->u.create2.phys)) - 1;
|
|
strncpy(hid->phys, ev->u.create2.phys, len);
|
|
len = min(sizeof(hid->uniq), sizeof(ev->u.create2.uniq)) - 1;
|
|
strncpy(hid->uniq, ev->u.create2.uniq, len);
|
|
|
|
hid->ll_driver = &uhid_hid_driver;
|
|
hid->bus = ev->u.create2.bus;
|
|
hid->vendor = ev->u.create2.vendor;
|
|
hid->product = ev->u.create2.product;
|
|
hid->version = ev->u.create2.version;
|
|
hid->country = ev->u.create2.country;
|
|
hid->driver_data = uhid;
|
|
hid->dev.parent = uhid_misc.this_device;
|
|
|
|
uhid->hid = hid;
|
|
uhid->running = true;
|
|
|
|
/* Adding of a HID device is done through a worker, to allow HID drivers
|
|
* which use feature requests during .probe to work, without they would
|
|
* be blocked on devlock, which is held by uhid_char_write.
|
|
*/
|
|
schedule_work(&uhid->worker);
|
|
|
|
return 0;
|
|
|
|
err_free:
|
|
kfree(uhid->rd_data);
|
|
uhid->rd_data = NULL;
|
|
uhid->rd_size = 0;
|
|
return ret;
|
|
}
|
|
|
|
static int uhid_dev_create(struct uhid_device *uhid,
|
|
struct uhid_event *ev)
|
|
{
|
|
struct uhid_create_req orig;
|
|
|
|
orig = ev->u.create;
|
|
|
|
if (orig.rd_size <= 0 || orig.rd_size > HID_MAX_DESCRIPTOR_SIZE)
|
|
return -EINVAL;
|
|
if (copy_from_user(&ev->u.create2.rd_data, orig.rd_data, orig.rd_size))
|
|
return -EFAULT;
|
|
|
|
memcpy(ev->u.create2.name, orig.name, sizeof(orig.name));
|
|
memcpy(ev->u.create2.phys, orig.phys, sizeof(orig.phys));
|
|
memcpy(ev->u.create2.uniq, orig.uniq, sizeof(orig.uniq));
|
|
ev->u.create2.rd_size = orig.rd_size;
|
|
ev->u.create2.bus = orig.bus;
|
|
ev->u.create2.vendor = orig.vendor;
|
|
ev->u.create2.product = orig.product;
|
|
ev->u.create2.version = orig.version;
|
|
ev->u.create2.country = orig.country;
|
|
|
|
return uhid_dev_create2(uhid, ev);
|
|
}
|
|
|
|
static int uhid_dev_destroy(struct uhid_device *uhid)
|
|
{
|
|
if (!uhid->hid)
|
|
return -EINVAL;
|
|
|
|
WRITE_ONCE(uhid->running, false);
|
|
wake_up_interruptible(&uhid->report_wait);
|
|
|
|
cancel_work_sync(&uhid->worker);
|
|
|
|
hid_destroy_device(uhid->hid);
|
|
uhid->hid = NULL;
|
|
kfree(uhid->rd_data);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
|
|
{
|
|
if (!READ_ONCE(uhid->running))
|
|
return -EINVAL;
|
|
|
|
hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
|
|
min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
|
|
{
|
|
if (!READ_ONCE(uhid->running))
|
|
return -EINVAL;
|
|
|
|
hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
|
|
min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int uhid_dev_get_report_reply(struct uhid_device *uhid,
|
|
struct uhid_event *ev)
|
|
{
|
|
if (!READ_ONCE(uhid->running))
|
|
return -EINVAL;
|
|
|
|
uhid_report_wake_up(uhid, ev->u.get_report_reply.id, ev);
|
|
return 0;
|
|
}
|
|
|
|
static int uhid_dev_set_report_reply(struct uhid_device *uhid,
|
|
struct uhid_event *ev)
|
|
{
|
|
if (!READ_ONCE(uhid->running))
|
|
return -EINVAL;
|
|
|
|
uhid_report_wake_up(uhid, ev->u.set_report_reply.id, ev);
|
|
return 0;
|
|
}
|
|
|
|
static int uhid_char_open(struct inode *inode, struct file *file)
|
|
{
|
|
struct uhid_device *uhid;
|
|
|
|
uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
|
|
if (!uhid)
|
|
return -ENOMEM;
|
|
|
|
mutex_init(&uhid->devlock);
|
|
mutex_init(&uhid->report_lock);
|
|
spin_lock_init(&uhid->qlock);
|
|
init_waitqueue_head(&uhid->waitq);
|
|
init_waitqueue_head(&uhid->report_wait);
|
|
uhid->running = false;
|
|
INIT_WORK(&uhid->worker, uhid_device_add_worker);
|
|
|
|
file->private_data = uhid;
|
|
stream_open(inode, file);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int uhid_char_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct uhid_device *uhid = file->private_data;
|
|
unsigned int i;
|
|
|
|
uhid_dev_destroy(uhid);
|
|
|
|
for (i = 0; i < UHID_BUFSIZE; ++i)
|
|
kfree(uhid->outq[i]);
|
|
|
|
kfree(uhid);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t uhid_char_read(struct file *file, char __user *buffer,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
struct uhid_device *uhid = file->private_data;
|
|
int ret;
|
|
unsigned long flags;
|
|
size_t len;
|
|
|
|
/* they need at least the "type" member of uhid_event */
|
|
if (count < sizeof(__u32))
|
|
return -EINVAL;
|
|
|
|
try_again:
|
|
if (file->f_flags & O_NONBLOCK) {
|
|
if (uhid->head == uhid->tail)
|
|
return -EAGAIN;
|
|
} else {
|
|
ret = wait_event_interruptible(uhid->waitq,
|
|
uhid->head != uhid->tail);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
ret = mutex_lock_interruptible(&uhid->devlock);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (uhid->head == uhid->tail) {
|
|
mutex_unlock(&uhid->devlock);
|
|
goto try_again;
|
|
} else {
|
|
len = min(count, sizeof(**uhid->outq));
|
|
if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
|
|
ret = -EFAULT;
|
|
} else {
|
|
kfree(uhid->outq[uhid->tail]);
|
|
uhid->outq[uhid->tail] = NULL;
|
|
|
|
spin_lock_irqsave(&uhid->qlock, flags);
|
|
uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
|
|
spin_unlock_irqrestore(&uhid->qlock, flags);
|
|
}
|
|
}
|
|
|
|
mutex_unlock(&uhid->devlock);
|
|
return ret ? ret : len;
|
|
}
|
|
|
|
static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
|
|
size_t count, loff_t *ppos)
|
|
{
|
|
struct uhid_device *uhid = file->private_data;
|
|
int ret;
|
|
size_t len;
|
|
|
|
/* we need at least the "type" member of uhid_event */
|
|
if (count < sizeof(__u32))
|
|
return -EINVAL;
|
|
|
|
ret = mutex_lock_interruptible(&uhid->devlock);
|
|
if (ret)
|
|
return ret;
|
|
|
|
memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
|
|
len = min(count, sizeof(uhid->input_buf));
|
|
|
|
ret = uhid_event_from_user(buffer, len, &uhid->input_buf);
|
|
if (ret)
|
|
goto unlock;
|
|
|
|
switch (uhid->input_buf.type) {
|
|
case UHID_CREATE:
|
|
/*
|
|
* 'struct uhid_create_req' contains a __user pointer which is
|
|
* copied from, so it's unsafe to allow this with elevated
|
|
* privileges (e.g. from a setuid binary) or via kernel_write().
|
|
*/
|
|
if (file->f_cred != current_cred() || uaccess_kernel()) {
|
|
pr_err_once("UHID_CREATE from different security context by process %d (%s), this is not allowed.\n",
|
|
task_tgid_vnr(current), current->comm);
|
|
ret = -EACCES;
|
|
goto unlock;
|
|
}
|
|
ret = uhid_dev_create(uhid, &uhid->input_buf);
|
|
break;
|
|
case UHID_CREATE2:
|
|
ret = uhid_dev_create2(uhid, &uhid->input_buf);
|
|
break;
|
|
case UHID_DESTROY:
|
|
ret = uhid_dev_destroy(uhid);
|
|
break;
|
|
case UHID_INPUT:
|
|
ret = uhid_dev_input(uhid, &uhid->input_buf);
|
|
break;
|
|
case UHID_INPUT2:
|
|
ret = uhid_dev_input2(uhid, &uhid->input_buf);
|
|
break;
|
|
case UHID_GET_REPORT_REPLY:
|
|
ret = uhid_dev_get_report_reply(uhid, &uhid->input_buf);
|
|
break;
|
|
case UHID_SET_REPORT_REPLY:
|
|
ret = uhid_dev_set_report_reply(uhid, &uhid->input_buf);
|
|
break;
|
|
default:
|
|
ret = -EOPNOTSUPP;
|
|
}
|
|
|
|
unlock:
|
|
mutex_unlock(&uhid->devlock);
|
|
|
|
/* return "count" not "len" to not confuse the caller */
|
|
return ret ? ret : count;
|
|
}
|
|
|
|
static __poll_t uhid_char_poll(struct file *file, poll_table *wait)
|
|
{
|
|
struct uhid_device *uhid = file->private_data;
|
|
__poll_t mask = EPOLLOUT | EPOLLWRNORM; /* uhid is always writable */
|
|
|
|
poll_wait(file, &uhid->waitq, wait);
|
|
|
|
if (uhid->head != uhid->tail)
|
|
mask |= EPOLLIN | EPOLLRDNORM;
|
|
|
|
return mask;
|
|
}
|
|
|
|
static const struct file_operations uhid_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = uhid_char_open,
|
|
.release = uhid_char_release,
|
|
.read = uhid_char_read,
|
|
.write = uhid_char_write,
|
|
.poll = uhid_char_poll,
|
|
.llseek = no_llseek,
|
|
};
|
|
|
|
static struct miscdevice uhid_misc = {
|
|
.fops = &uhid_fops,
|
|
.minor = UHID_MINOR,
|
|
.name = UHID_NAME,
|
|
};
|
|
module_misc_device(uhid_misc);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
|
|
MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");
|
|
MODULE_ALIAS_MISCDEV(UHID_MINOR);
|
|
MODULE_ALIAS("devname:" UHID_NAME);
|