linux/drivers/input/evdev.c
Kenny Levinsen 4ba8b8aec5 Input: evdev - per-client waitgroups
All evdev clients share a common waitgroup. On new input events, all
clients waiting on this waitgroup are woken up, even those filtering out
the events, possibly more than once per event. This leads to duplicated
and unwanted wakeups.

Split the shared waitgroup into per-client waitgroups for more
fine-grained wakeups.

Signed-off-by: Kenny Levinsen <kl@kl.wtf>
Link: https://lore.kernel.org/r/20200429184126.2155-1-kl@kl.wtf
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
2020-10-06 18:34:15 -07:00

1447 lines
32 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* Event char devices, giving access to raw input device events.
*
* Copyright (c) 1999-2002 Vojtech Pavlik
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#define EVDEV_MINOR_BASE 64
#define EVDEV_MINORS 32
#define EVDEV_MIN_BUFFER_SIZE 64U
#define EVDEV_BUF_PACKETS 8
#include <linux/poll.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/input/mt.h>
#include <linux/major.h>
#include <linux/device.h>
#include <linux/cdev.h>
#include "input-compat.h"
struct evdev {
int open;
struct input_handle handle;
struct evdev_client __rcu *grab;
struct list_head client_list;
spinlock_t client_lock; /* protects client_list */
struct mutex mutex;
struct device dev;
struct cdev cdev;
bool exist;
};
struct evdev_client {
unsigned int head;
unsigned int tail;
unsigned int packet_head; /* [future] position of the first element of next packet */
spinlock_t buffer_lock; /* protects access to buffer, head and tail */
wait_queue_head_t wait;
struct fasync_struct *fasync;
struct evdev *evdev;
struct list_head node;
enum input_clock_type clk_type;
bool revoked;
unsigned long *evmasks[EV_CNT];
unsigned int bufsize;
struct input_event buffer[];
};
static size_t evdev_get_mask_cnt(unsigned int type)
{
static const size_t counts[EV_CNT] = {
/* EV_SYN==0 is EV_CNT, _not_ SYN_CNT, see EVIOCGBIT */
[EV_SYN] = EV_CNT,
[EV_KEY] = KEY_CNT,
[EV_REL] = REL_CNT,
[EV_ABS] = ABS_CNT,
[EV_MSC] = MSC_CNT,
[EV_SW] = SW_CNT,
[EV_LED] = LED_CNT,
[EV_SND] = SND_CNT,
[EV_FF] = FF_CNT,
};
return (type < EV_CNT) ? counts[type] : 0;
}
/* requires the buffer lock to be held */
static bool __evdev_is_filtered(struct evdev_client *client,
unsigned int type,
unsigned int code)
{
unsigned long *mask;
size_t cnt;
/* EV_SYN and unknown codes are never filtered */
if (type == EV_SYN || type >= EV_CNT)
return false;
/* first test whether the type is filtered */
mask = client->evmasks[0];
if (mask && !test_bit(type, mask))
return true;
/* unknown values are never filtered */
cnt = evdev_get_mask_cnt(type);
if (!cnt || code >= cnt)
return false;
mask = client->evmasks[type];
return mask && !test_bit(code, mask);
}
/* flush queued events of type @type, caller must hold client->buffer_lock */
static void __evdev_flush_queue(struct evdev_client *client, unsigned int type)
{
unsigned int i, head, num;
unsigned int mask = client->bufsize - 1;
bool is_report;
struct input_event *ev;
BUG_ON(type == EV_SYN);
head = client->tail;
client->packet_head = client->tail;
/* init to 1 so a leading SYN_REPORT will not be dropped */
num = 1;
for (i = client->tail; i != client->head; i = (i + 1) & mask) {
ev = &client->buffer[i];
is_report = ev->type == EV_SYN && ev->code == SYN_REPORT;
if (ev->type == type) {
/* drop matched entry */
continue;
} else if (is_report && !num) {
/* drop empty SYN_REPORT groups */
continue;
} else if (head != i) {
/* move entry to fill the gap */
client->buffer[head] = *ev;
}
num++;
head = (head + 1) & mask;
if (is_report) {
num = 0;
client->packet_head = head;
}
}
client->head = head;
}
static void __evdev_queue_syn_dropped(struct evdev_client *client)
{
ktime_t *ev_time = input_get_timestamp(client->evdev->handle.dev);
struct timespec64 ts = ktime_to_timespec64(ev_time[client->clk_type]);
struct input_event ev;
ev.input_event_sec = ts.tv_sec;
ev.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
ev.type = EV_SYN;
ev.code = SYN_DROPPED;
ev.value = 0;
client->buffer[client->head++] = ev;
client->head &= client->bufsize - 1;
if (unlikely(client->head == client->tail)) {
/* drop queue but keep our SYN_DROPPED event */
client->tail = (client->head - 1) & (client->bufsize - 1);
client->packet_head = client->tail;
}
}
static void evdev_queue_syn_dropped(struct evdev_client *client)
{
unsigned long flags;
spin_lock_irqsave(&client->buffer_lock, flags);
__evdev_queue_syn_dropped(client);
spin_unlock_irqrestore(&client->buffer_lock, flags);
}
static int evdev_set_clk_type(struct evdev_client *client, unsigned int clkid)
{
unsigned long flags;
enum input_clock_type clk_type;
switch (clkid) {
case CLOCK_REALTIME:
clk_type = INPUT_CLK_REAL;
break;
case CLOCK_MONOTONIC:
clk_type = INPUT_CLK_MONO;
break;
case CLOCK_BOOTTIME:
clk_type = INPUT_CLK_BOOT;
break;
default:
return -EINVAL;
}
if (client->clk_type != clk_type) {
client->clk_type = clk_type;
/*
* Flush pending events and queue SYN_DROPPED event,
* but only if the queue is not empty.
*/
spin_lock_irqsave(&client->buffer_lock, flags);
if (client->head != client->tail) {
client->packet_head = client->head = client->tail;
__evdev_queue_syn_dropped(client);
}
spin_unlock_irqrestore(&client->buffer_lock, flags);
}
return 0;
}
static void __pass_event(struct evdev_client *client,
const struct input_event *event)
{
client->buffer[client->head++] = *event;
client->head &= client->bufsize - 1;
if (unlikely(client->head == client->tail)) {
/*
* This effectively "drops" all unconsumed events, leaving
* EV_SYN/SYN_DROPPED plus the newest event in the queue.
*/
client->tail = (client->head - 2) & (client->bufsize - 1);
client->buffer[client->tail] = (struct input_event) {
.input_event_sec = event->input_event_sec,
.input_event_usec = event->input_event_usec,
.type = EV_SYN,
.code = SYN_DROPPED,
.value = 0,
};
client->packet_head = client->tail;
}
if (event->type == EV_SYN && event->code == SYN_REPORT) {
client->packet_head = client->head;
kill_fasync(&client->fasync, SIGIO, POLL_IN);
}
}
static void evdev_pass_values(struct evdev_client *client,
const struct input_value *vals, unsigned int count,
ktime_t *ev_time)
{
const struct input_value *v;
struct input_event event;
struct timespec64 ts;
bool wakeup = false;
if (client->revoked)
return;
ts = ktime_to_timespec64(ev_time[client->clk_type]);
event.input_event_sec = ts.tv_sec;
event.input_event_usec = ts.tv_nsec / NSEC_PER_USEC;
/* Interrupts are disabled, just acquire the lock. */
spin_lock(&client->buffer_lock);
for (v = vals; v != vals + count; v++) {
if (__evdev_is_filtered(client, v->type, v->code))
continue;
if (v->type == EV_SYN && v->code == SYN_REPORT) {
/* drop empty SYN_REPORT */
if (client->packet_head == client->head)
continue;
wakeup = true;
}
event.type = v->type;
event.code = v->code;
event.value = v->value;
__pass_event(client, &event);
}
spin_unlock(&client->buffer_lock);
if (wakeup)
wake_up_interruptible_poll(&client->wait,
EPOLLIN | EPOLLOUT | EPOLLRDNORM | EPOLLWRNORM);
}
/*
* Pass incoming events to all connected clients.
*/
static void evdev_events(struct input_handle *handle,
const struct input_value *vals, unsigned int count)
{
struct evdev *evdev = handle->private;
struct evdev_client *client;
ktime_t *ev_time = input_get_timestamp(handle->dev);
rcu_read_lock();
client = rcu_dereference(evdev->grab);
if (client)
evdev_pass_values(client, vals, count, ev_time);
else
list_for_each_entry_rcu(client, &evdev->client_list, node)
evdev_pass_values(client, vals, count, ev_time);
rcu_read_unlock();
}
/*
* Pass incoming event to all connected clients.
*/
static void evdev_event(struct input_handle *handle,
unsigned int type, unsigned int code, int value)
{
struct input_value vals[] = { { type, code, value } };
evdev_events(handle, vals, 1);
}
static int evdev_fasync(int fd, struct file *file, int on)
{
struct evdev_client *client = file->private_data;
return fasync_helper(fd, file, on, &client->fasync);
}
static void evdev_free(struct device *dev)
{
struct evdev *evdev = container_of(dev, struct evdev, dev);
input_put_device(evdev->handle.dev);
kfree(evdev);
}
/*
* Grabs an event device (along with underlying input device).
* This function is called with evdev->mutex taken.
*/
static int evdev_grab(struct evdev *evdev, struct evdev_client *client)
{
int error;
if (evdev->grab)
return -EBUSY;
error = input_grab_device(&evdev->handle);
if (error)
return error;
rcu_assign_pointer(evdev->grab, client);
return 0;
}
static int evdev_ungrab(struct evdev *evdev, struct evdev_client *client)
{
struct evdev_client *grab = rcu_dereference_protected(evdev->grab,
lockdep_is_held(&evdev->mutex));
if (grab != client)
return -EINVAL;
rcu_assign_pointer(evdev->grab, NULL);
synchronize_rcu();
input_release_device(&evdev->handle);
return 0;
}
static void evdev_attach_client(struct evdev *evdev,
struct evdev_client *client)
{
spin_lock(&evdev->client_lock);
list_add_tail_rcu(&client->node, &evdev->client_list);
spin_unlock(&evdev->client_lock);
}
static void evdev_detach_client(struct evdev *evdev,
struct evdev_client *client)
{
spin_lock(&evdev->client_lock);
list_del_rcu(&client->node);
spin_unlock(&evdev->client_lock);
synchronize_rcu();
}
static int evdev_open_device(struct evdev *evdev)
{
int retval;
retval = mutex_lock_interruptible(&evdev->mutex);
if (retval)
return retval;
if (!evdev->exist)
retval = -ENODEV;
else if (!evdev->open++) {
retval = input_open_device(&evdev->handle);
if (retval)
evdev->open--;
}
mutex_unlock(&evdev->mutex);
return retval;
}
static void evdev_close_device(struct evdev *evdev)
{
mutex_lock(&evdev->mutex);
if (evdev->exist && !--evdev->open)
input_close_device(&evdev->handle);
mutex_unlock(&evdev->mutex);
}
/*
* Wake up users waiting for IO so they can disconnect from
* dead device.
*/
static void evdev_hangup(struct evdev *evdev)
{
struct evdev_client *client;
spin_lock(&evdev->client_lock);
list_for_each_entry(client, &evdev->client_list, node) {
kill_fasync(&client->fasync, SIGIO, POLL_HUP);
wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
}
spin_unlock(&evdev->client_lock);
}
static int evdev_release(struct inode *inode, struct file *file)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
unsigned int i;
mutex_lock(&evdev->mutex);
if (evdev->exist && !client->revoked)
input_flush_device(&evdev->handle, file);
evdev_ungrab(evdev, client);
mutex_unlock(&evdev->mutex);
evdev_detach_client(evdev, client);
for (i = 0; i < EV_CNT; ++i)
bitmap_free(client->evmasks[i]);
kvfree(client);
evdev_close_device(evdev);
return 0;
}
static unsigned int evdev_compute_buffer_size(struct input_dev *dev)
{
unsigned int n_events =
max(dev->hint_events_per_packet * EVDEV_BUF_PACKETS,
EVDEV_MIN_BUFFER_SIZE);
return roundup_pow_of_two(n_events);
}
static int evdev_open(struct inode *inode, struct file *file)
{
struct evdev *evdev = container_of(inode->i_cdev, struct evdev, cdev);
unsigned int bufsize = evdev_compute_buffer_size(evdev->handle.dev);
struct evdev_client *client;
int error;
client = kvzalloc(struct_size(client, buffer, bufsize), GFP_KERNEL);
if (!client)
return -ENOMEM;
init_waitqueue_head(&client->wait);
client->bufsize = bufsize;
spin_lock_init(&client->buffer_lock);
client->evdev = evdev;
evdev_attach_client(evdev, client);
error = evdev_open_device(evdev);
if (error)
goto err_free_client;
file->private_data = client;
stream_open(inode, file);
return 0;
err_free_client:
evdev_detach_client(evdev, client);
kvfree(client);
return error;
}
static ssize_t evdev_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
struct input_event event;
int retval = 0;
if (count != 0 && count < input_event_size())
return -EINVAL;
retval = mutex_lock_interruptible(&evdev->mutex);
if (retval)
return retval;
if (!evdev->exist || client->revoked) {
retval = -ENODEV;
goto out;
}
while (retval + input_event_size() <= count) {
if (input_event_from_user(buffer + retval, &event)) {
retval = -EFAULT;
goto out;
}
retval += input_event_size();
input_inject_event(&evdev->handle,
event.type, event.code, event.value);
cond_resched();
}
out:
mutex_unlock(&evdev->mutex);
return retval;
}
static int evdev_fetch_next_event(struct evdev_client *client,
struct input_event *event)
{
int have_event;
spin_lock_irq(&client->buffer_lock);
have_event = client->packet_head != client->tail;
if (have_event) {
*event = client->buffer[client->tail++];
client->tail &= client->bufsize - 1;
}
spin_unlock_irq(&client->buffer_lock);
return have_event;
}
static ssize_t evdev_read(struct file *file, char __user *buffer,
size_t count, loff_t *ppos)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
struct input_event event;
size_t read = 0;
int error;
if (count != 0 && count < input_event_size())
return -EINVAL;
for (;;) {
if (!evdev->exist || client->revoked)
return -ENODEV;
if (client->packet_head == client->tail &&
(file->f_flags & O_NONBLOCK))
return -EAGAIN;
/*
* count == 0 is special - no IO is done but we check
* for error conditions (see above).
*/
if (count == 0)
break;
while (read + input_event_size() <= count &&
evdev_fetch_next_event(client, &event)) {
if (input_event_to_user(buffer + read, &event))
return -EFAULT;
read += input_event_size();
}
if (read)
break;
if (!(file->f_flags & O_NONBLOCK)) {
error = wait_event_interruptible(client->wait,
client->packet_head != client->tail ||
!evdev->exist || client->revoked);
if (error)
return error;
}
}
return read;
}
/* No kernel lock - fine */
static __poll_t evdev_poll(struct file *file, poll_table *wait)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
__poll_t mask;
poll_wait(file, &client->wait, wait);
if (evdev->exist && !client->revoked)
mask = EPOLLOUT | EPOLLWRNORM;
else
mask = EPOLLHUP | EPOLLERR;
if (client->packet_head != client->tail)
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
#ifdef CONFIG_COMPAT
#define BITS_PER_LONG_COMPAT (sizeof(compat_long_t) * 8)
#define BITS_TO_LONGS_COMPAT(x) ((((x) - 1) / BITS_PER_LONG_COMPAT) + 1)
#ifdef __BIG_ENDIAN
static int bits_to_user(unsigned long *bits, unsigned int maxbit,
unsigned int maxlen, void __user *p, int compat)
{
int len, i;
if (compat) {
len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
if (len > maxlen)
len = maxlen;
for (i = 0; i < len / sizeof(compat_long_t); i++)
if (copy_to_user((compat_long_t __user *) p + i,
(compat_long_t *) bits +
i + 1 - ((i % 2) << 1),
sizeof(compat_long_t)))
return -EFAULT;
} else {
len = BITS_TO_LONGS(maxbit) * sizeof(long);
if (len > maxlen)
len = maxlen;
if (copy_to_user(p, bits, len))
return -EFAULT;
}
return len;
}
static int bits_from_user(unsigned long *bits, unsigned int maxbit,
unsigned int maxlen, const void __user *p, int compat)
{
int len, i;
if (compat) {
if (maxlen % sizeof(compat_long_t))
return -EINVAL;
len = BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t);
if (len > maxlen)
len = maxlen;
for (i = 0; i < len / sizeof(compat_long_t); i++)
if (copy_from_user((compat_long_t *) bits +
i + 1 - ((i % 2) << 1),
(compat_long_t __user *) p + i,
sizeof(compat_long_t)))
return -EFAULT;
if (i % 2)
*((compat_long_t *) bits + i - 1) = 0;
} else {
if (maxlen % sizeof(long))
return -EINVAL;
len = BITS_TO_LONGS(maxbit) * sizeof(long);
if (len > maxlen)
len = maxlen;
if (copy_from_user(bits, p, len))
return -EFAULT;
}
return len;
}
#else
static int bits_to_user(unsigned long *bits, unsigned int maxbit,
unsigned int maxlen, void __user *p, int compat)
{
int len = compat ?
BITS_TO_LONGS_COMPAT(maxbit) * sizeof(compat_long_t) :
BITS_TO_LONGS(maxbit) * sizeof(long);
if (len > maxlen)
len = maxlen;
return copy_to_user(p, bits, len) ? -EFAULT : len;
}
static int bits_from_user(unsigned long *bits, unsigned int maxbit,
unsigned int maxlen, const void __user *p, int compat)
{
size_t chunk_size = compat ? sizeof(compat_long_t) : sizeof(long);
int len;
if (maxlen % chunk_size)
return -EINVAL;
len = compat ? BITS_TO_LONGS_COMPAT(maxbit) : BITS_TO_LONGS(maxbit);
len *= chunk_size;
if (len > maxlen)
len = maxlen;
return copy_from_user(bits, p, len) ? -EFAULT : len;
}
#endif /* __BIG_ENDIAN */
#else
static int bits_to_user(unsigned long *bits, unsigned int maxbit,
unsigned int maxlen, void __user *p, int compat)
{
int len = BITS_TO_LONGS(maxbit) * sizeof(long);
if (len > maxlen)
len = maxlen;
return copy_to_user(p, bits, len) ? -EFAULT : len;
}
static int bits_from_user(unsigned long *bits, unsigned int maxbit,
unsigned int maxlen, const void __user *p, int compat)
{
int len;
if (maxlen % sizeof(long))
return -EINVAL;
len = BITS_TO_LONGS(maxbit) * sizeof(long);
if (len > maxlen)
len = maxlen;
return copy_from_user(bits, p, len) ? -EFAULT : len;
}
#endif /* CONFIG_COMPAT */
static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
{
int len;
if (!str)
return -ENOENT;
len = strlen(str) + 1;
if (len > maxlen)
len = maxlen;
return copy_to_user(p, str, len) ? -EFAULT : len;
}
static int handle_eviocgbit(struct input_dev *dev,
unsigned int type, unsigned int size,
void __user *p, int compat_mode)
{
unsigned long *bits;
int len;
switch (type) {
case 0: bits = dev->evbit; len = EV_MAX; break;
case EV_KEY: bits = dev->keybit; len = KEY_MAX; break;
case EV_REL: bits = dev->relbit; len = REL_MAX; break;
case EV_ABS: bits = dev->absbit; len = ABS_MAX; break;
case EV_MSC: bits = dev->mscbit; len = MSC_MAX; break;
case EV_LED: bits = dev->ledbit; len = LED_MAX; break;
case EV_SND: bits = dev->sndbit; len = SND_MAX; break;
case EV_FF: bits = dev->ffbit; len = FF_MAX; break;
case EV_SW: bits = dev->swbit; len = SW_MAX; break;
default: return -EINVAL;
}
return bits_to_user(bits, len, size, p, compat_mode);
}
static int evdev_handle_get_keycode(struct input_dev *dev, void __user *p)
{
struct input_keymap_entry ke = {
.len = sizeof(unsigned int),
.flags = 0,
};
int __user *ip = (int __user *)p;
int error;
/* legacy case */
if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
return -EFAULT;
error = input_get_keycode(dev, &ke);
if (error)
return error;
if (put_user(ke.keycode, ip + 1))
return -EFAULT;
return 0;
}
static int evdev_handle_get_keycode_v2(struct input_dev *dev, void __user *p)
{
struct input_keymap_entry ke;
int error;
if (copy_from_user(&ke, p, sizeof(ke)))
return -EFAULT;
error = input_get_keycode(dev, &ke);
if (error)
return error;
if (copy_to_user(p, &ke, sizeof(ke)))
return -EFAULT;
return 0;
}
static int evdev_handle_set_keycode(struct input_dev *dev, void __user *p)
{
struct input_keymap_entry ke = {
.len = sizeof(unsigned int),
.flags = 0,
};
int __user *ip = (int __user *)p;
if (copy_from_user(ke.scancode, p, sizeof(unsigned int)))
return -EFAULT;
if (get_user(ke.keycode, ip + 1))
return -EFAULT;
return input_set_keycode(dev, &ke);
}
static int evdev_handle_set_keycode_v2(struct input_dev *dev, void __user *p)
{
struct input_keymap_entry ke;
if (copy_from_user(&ke, p, sizeof(ke)))
return -EFAULT;
if (ke.len > sizeof(ke.scancode))
return -EINVAL;
return input_set_keycode(dev, &ke);
}
/*
* If we transfer state to the user, we should flush all pending events
* of the same type from the client's queue. Otherwise, they might end up
* with duplicate events, which can screw up client's state tracking.
* If bits_to_user fails after flushing the queue, we queue a SYN_DROPPED
* event so user-space will notice missing events.
*
* LOCKING:
* We need to take event_lock before buffer_lock to avoid dead-locks. But we
* need the even_lock only to guarantee consistent state. We can safely release
* it while flushing the queue. This allows input-core to handle filters while
* we flush the queue.
*/
static int evdev_handle_get_val(struct evdev_client *client,
struct input_dev *dev, unsigned int type,
unsigned long *bits, unsigned int maxbit,
unsigned int maxlen, void __user *p,
int compat)
{
int ret;
unsigned long *mem;
mem = bitmap_alloc(maxbit, GFP_KERNEL);
if (!mem)
return -ENOMEM;
spin_lock_irq(&dev->event_lock);
spin_lock(&client->buffer_lock);
bitmap_copy(mem, bits, maxbit);
spin_unlock(&dev->event_lock);
__evdev_flush_queue(client, type);
spin_unlock_irq(&client->buffer_lock);
ret = bits_to_user(mem, maxbit, maxlen, p, compat);
if (ret < 0)
evdev_queue_syn_dropped(client);
bitmap_free(mem);
return ret;
}
static int evdev_handle_mt_request(struct input_dev *dev,
unsigned int size,
int __user *ip)
{
const struct input_mt *mt = dev->mt;
unsigned int code;
int max_slots;
int i;
if (get_user(code, &ip[0]))
return -EFAULT;
if (!mt || !input_is_mt_value(code))
return -EINVAL;
max_slots = (size - sizeof(__u32)) / sizeof(__s32);
for (i = 0; i < mt->num_slots && i < max_slots; i++) {
int value = input_mt_get_value(&mt->slots[i], code);
if (put_user(value, &ip[1 + i]))
return -EFAULT;
}
return 0;
}
static int evdev_revoke(struct evdev *evdev, struct evdev_client *client,
struct file *file)
{
client->revoked = true;
evdev_ungrab(evdev, client);
input_flush_device(&evdev->handle, file);
wake_up_interruptible_poll(&client->wait, EPOLLHUP | EPOLLERR);
return 0;
}
/* must be called with evdev-mutex held */
static int evdev_set_mask(struct evdev_client *client,
unsigned int type,
const void __user *codes,
u32 codes_size,
int compat)
{
unsigned long flags, *mask, *oldmask;
size_t cnt;
int error;
/* we allow unknown types and 'codes_size > size' for forward-compat */
cnt = evdev_get_mask_cnt(type);
if (!cnt)
return 0;
mask = bitmap_zalloc(cnt, GFP_KERNEL);
if (!mask)
return -ENOMEM;
error = bits_from_user(mask, cnt - 1, codes_size, codes, compat);
if (error < 0) {
bitmap_free(mask);
return error;
}
spin_lock_irqsave(&client->buffer_lock, flags);
oldmask = client->evmasks[type];
client->evmasks[type] = mask;
spin_unlock_irqrestore(&client->buffer_lock, flags);
bitmap_free(oldmask);
return 0;
}
/* must be called with evdev-mutex held */
static int evdev_get_mask(struct evdev_client *client,
unsigned int type,
void __user *codes,
u32 codes_size,
int compat)
{
unsigned long *mask;
size_t cnt, size, xfer_size;
int i;
int error;
/* we allow unknown types and 'codes_size > size' for forward-compat */
cnt = evdev_get_mask_cnt(type);
size = sizeof(unsigned long) * BITS_TO_LONGS(cnt);
xfer_size = min_t(size_t, codes_size, size);
if (cnt > 0) {
mask = client->evmasks[type];
if (mask) {
error = bits_to_user(mask, cnt - 1,
xfer_size, codes, compat);
if (error < 0)
return error;
} else {
/* fake mask with all bits set */
for (i = 0; i < xfer_size; i++)
if (put_user(0xffU, (u8 __user *)codes + i))
return -EFAULT;
}
}
if (xfer_size < codes_size)
if (clear_user(codes + xfer_size, codes_size - xfer_size))
return -EFAULT;
return 0;
}
static long evdev_do_ioctl(struct file *file, unsigned int cmd,
void __user *p, int compat_mode)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
struct input_dev *dev = evdev->handle.dev;
struct input_absinfo abs;
struct input_mask mask;
struct ff_effect effect;
int __user *ip = (int __user *)p;
unsigned int i, t, u, v;
unsigned int size;
int error;
/* First we check for fixed-length commands */
switch (cmd) {
case EVIOCGVERSION:
return put_user(EV_VERSION, ip);
case EVIOCGID:
if (copy_to_user(p, &dev->id, sizeof(struct input_id)))
return -EFAULT;
return 0;
case EVIOCGREP:
if (!test_bit(EV_REP, dev->evbit))
return -ENOSYS;
if (put_user(dev->rep[REP_DELAY], ip))
return -EFAULT;
if (put_user(dev->rep[REP_PERIOD], ip + 1))
return -EFAULT;
return 0;
case EVIOCSREP:
if (!test_bit(EV_REP, dev->evbit))
return -ENOSYS;
if (get_user(u, ip))
return -EFAULT;
if (get_user(v, ip + 1))
return -EFAULT;
input_inject_event(&evdev->handle, EV_REP, REP_DELAY, u);
input_inject_event(&evdev->handle, EV_REP, REP_PERIOD, v);
return 0;
case EVIOCRMFF:
return input_ff_erase(dev, (int)(unsigned long) p, file);
case EVIOCGEFFECTS:
i = test_bit(EV_FF, dev->evbit) ?
dev->ff->max_effects : 0;
if (put_user(i, ip))
return -EFAULT;
return 0;
case EVIOCGRAB:
if (p)
return evdev_grab(evdev, client);
else
return evdev_ungrab(evdev, client);
case EVIOCREVOKE:
if (p)
return -EINVAL;
else
return evdev_revoke(evdev, client, file);
case EVIOCGMASK: {
void __user *codes_ptr;
if (copy_from_user(&mask, p, sizeof(mask)))
return -EFAULT;
codes_ptr = (void __user *)(unsigned long)mask.codes_ptr;
return evdev_get_mask(client,
mask.type, codes_ptr, mask.codes_size,
compat_mode);
}
case EVIOCSMASK: {
const void __user *codes_ptr;
if (copy_from_user(&mask, p, sizeof(mask)))
return -EFAULT;
codes_ptr = (const void __user *)(unsigned long)mask.codes_ptr;
return evdev_set_mask(client,
mask.type, codes_ptr, mask.codes_size,
compat_mode);
}
case EVIOCSCLOCKID:
if (copy_from_user(&i, p, sizeof(unsigned int)))
return -EFAULT;
return evdev_set_clk_type(client, i);
case EVIOCGKEYCODE:
return evdev_handle_get_keycode(dev, p);
case EVIOCSKEYCODE:
return evdev_handle_set_keycode(dev, p);
case EVIOCGKEYCODE_V2:
return evdev_handle_get_keycode_v2(dev, p);
case EVIOCSKEYCODE_V2:
return evdev_handle_set_keycode_v2(dev, p);
}
size = _IOC_SIZE(cmd);
/* Now check variable-length commands */
#define EVIOC_MASK_SIZE(nr) ((nr) & ~(_IOC_SIZEMASK << _IOC_SIZESHIFT))
switch (EVIOC_MASK_SIZE(cmd)) {
case EVIOCGPROP(0):
return bits_to_user(dev->propbit, INPUT_PROP_MAX,
size, p, compat_mode);
case EVIOCGMTSLOTS(0):
return evdev_handle_mt_request(dev, size, ip);
case EVIOCGKEY(0):
return evdev_handle_get_val(client, dev, EV_KEY, dev->key,
KEY_MAX, size, p, compat_mode);
case EVIOCGLED(0):
return evdev_handle_get_val(client, dev, EV_LED, dev->led,
LED_MAX, size, p, compat_mode);
case EVIOCGSND(0):
return evdev_handle_get_val(client, dev, EV_SND, dev->snd,
SND_MAX, size, p, compat_mode);
case EVIOCGSW(0):
return evdev_handle_get_val(client, dev, EV_SW, dev->sw,
SW_MAX, size, p, compat_mode);
case EVIOCGNAME(0):
return str_to_user(dev->name, size, p);
case EVIOCGPHYS(0):
return str_to_user(dev->phys, size, p);
case EVIOCGUNIQ(0):
return str_to_user(dev->uniq, size, p);
case EVIOC_MASK_SIZE(EVIOCSFF):
if (input_ff_effect_from_user(p, size, &effect))
return -EFAULT;
error = input_ff_upload(dev, &effect, file);
if (error)
return error;
if (put_user(effect.id, &(((struct ff_effect __user *)p)->id)))
return -EFAULT;
return 0;
}
/* Multi-number variable-length handlers */
if (_IOC_TYPE(cmd) != 'E')
return -EINVAL;
if (_IOC_DIR(cmd) == _IOC_READ) {
if ((_IOC_NR(cmd) & ~EV_MAX) == _IOC_NR(EVIOCGBIT(0, 0)))
return handle_eviocgbit(dev,
_IOC_NR(cmd) & EV_MAX, size,
p, compat_mode);
if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCGABS(0))) {
if (!dev->absinfo)
return -EINVAL;
t = _IOC_NR(cmd) & ABS_MAX;
abs = dev->absinfo[t];
if (copy_to_user(p, &abs, min_t(size_t,
size, sizeof(struct input_absinfo))))
return -EFAULT;
return 0;
}
}
if (_IOC_DIR(cmd) == _IOC_WRITE) {
if ((_IOC_NR(cmd) & ~ABS_MAX) == _IOC_NR(EVIOCSABS(0))) {
if (!dev->absinfo)
return -EINVAL;
t = _IOC_NR(cmd) & ABS_MAX;
if (copy_from_user(&abs, p, min_t(size_t,
size, sizeof(struct input_absinfo))))
return -EFAULT;
if (size < sizeof(struct input_absinfo))
abs.resolution = 0;
/* We can't change number of reserved MT slots */
if (t == ABS_MT_SLOT)
return -EINVAL;
/*
* Take event lock to ensure that we are not
* changing device parameters in the middle
* of event.
*/
spin_lock_irq(&dev->event_lock);
dev->absinfo[t] = abs;
spin_unlock_irq(&dev->event_lock);
return 0;
}
}
return -EINVAL;
}
static long evdev_ioctl_handler(struct file *file, unsigned int cmd,
void __user *p, int compat_mode)
{
struct evdev_client *client = file->private_data;
struct evdev *evdev = client->evdev;
int retval;
retval = mutex_lock_interruptible(&evdev->mutex);
if (retval)
return retval;
if (!evdev->exist || client->revoked) {
retval = -ENODEV;
goto out;
}
retval = evdev_do_ioctl(file, cmd, p, compat_mode);
out:
mutex_unlock(&evdev->mutex);
return retval;
}
static long evdev_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
return evdev_ioctl_handler(file, cmd, (void __user *)arg, 0);
}
#ifdef CONFIG_COMPAT
static long evdev_ioctl_compat(struct file *file,
unsigned int cmd, unsigned long arg)
{
return evdev_ioctl_handler(file, cmd, compat_ptr(arg), 1);
}
#endif
static const struct file_operations evdev_fops = {
.owner = THIS_MODULE,
.read = evdev_read,
.write = evdev_write,
.poll = evdev_poll,
.open = evdev_open,
.release = evdev_release,
.unlocked_ioctl = evdev_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = evdev_ioctl_compat,
#endif
.fasync = evdev_fasync,
.llseek = no_llseek,
};
/*
* Mark device non-existent. This disables writes, ioctls and
* prevents new users from opening the device. Already posted
* blocking reads will stay, however new ones will fail.
*/
static void evdev_mark_dead(struct evdev *evdev)
{
mutex_lock(&evdev->mutex);
evdev->exist = false;
mutex_unlock(&evdev->mutex);
}
static void evdev_cleanup(struct evdev *evdev)
{
struct input_handle *handle = &evdev->handle;
evdev_mark_dead(evdev);
evdev_hangup(evdev);
/* evdev is marked dead so no one else accesses evdev->open */
if (evdev->open) {
input_flush_device(handle, NULL);
input_close_device(handle);
}
}
/*
* Create new evdev device. Note that input core serializes calls
* to connect and disconnect.
*/
static int evdev_connect(struct input_handler *handler, struct input_dev *dev,
const struct input_device_id *id)
{
struct evdev *evdev;
int minor;
int dev_no;
int error;
minor = input_get_new_minor(EVDEV_MINOR_BASE, EVDEV_MINORS, true);
if (minor < 0) {
error = minor;
pr_err("failed to reserve new minor: %d\n", error);
return error;
}
evdev = kzalloc(sizeof(struct evdev), GFP_KERNEL);
if (!evdev) {
error = -ENOMEM;
goto err_free_minor;
}
INIT_LIST_HEAD(&evdev->client_list);
spin_lock_init(&evdev->client_lock);
mutex_init(&evdev->mutex);
evdev->exist = true;
dev_no = minor;
/* Normalize device number if it falls into legacy range */
if (dev_no < EVDEV_MINOR_BASE + EVDEV_MINORS)
dev_no -= EVDEV_MINOR_BASE;
dev_set_name(&evdev->dev, "event%d", dev_no);
evdev->handle.dev = input_get_device(dev);
evdev->handle.name = dev_name(&evdev->dev);
evdev->handle.handler = handler;
evdev->handle.private = evdev;
evdev->dev.devt = MKDEV(INPUT_MAJOR, minor);
evdev->dev.class = &input_class;
evdev->dev.parent = &dev->dev;
evdev->dev.release = evdev_free;
device_initialize(&evdev->dev);
error = input_register_handle(&evdev->handle);
if (error)
goto err_free_evdev;
cdev_init(&evdev->cdev, &evdev_fops);
error = cdev_device_add(&evdev->cdev, &evdev->dev);
if (error)
goto err_cleanup_evdev;
return 0;
err_cleanup_evdev:
evdev_cleanup(evdev);
input_unregister_handle(&evdev->handle);
err_free_evdev:
put_device(&evdev->dev);
err_free_minor:
input_free_minor(minor);
return error;
}
static void evdev_disconnect(struct input_handle *handle)
{
struct evdev *evdev = handle->private;
cdev_device_del(&evdev->cdev, &evdev->dev);
evdev_cleanup(evdev);
input_free_minor(MINOR(evdev->dev.devt));
input_unregister_handle(handle);
put_device(&evdev->dev);
}
static const struct input_device_id evdev_ids[] = {
{ .driver_info = 1 }, /* Matches all devices */
{ }, /* Terminating zero entry */
};
MODULE_DEVICE_TABLE(input, evdev_ids);
static struct input_handler evdev_handler = {
.event = evdev_event,
.events = evdev_events,
.connect = evdev_connect,
.disconnect = evdev_disconnect,
.legacy_minors = true,
.minor = EVDEV_MINOR_BASE,
.name = "evdev",
.id_table = evdev_ids,
};
static int __init evdev_init(void)
{
return input_register_handler(&evdev_handler);
}
static void __exit evdev_exit(void)
{
input_unregister_handler(&evdev_handler);
}
module_init(evdev_init);
module_exit(evdev_exit);
MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
MODULE_DESCRIPTION("Input driver event char devices");
MODULE_LICENSE("GPL");