freebsd-skq/sys/dev/evdev/cdev.c
2016-09-12 17:29:20 +00:00

861 lines
20 KiB
C

/*-
* Copyright (c) 2014 Jakub Wojciech Klama <jceel@FreeBSD.org>
* Copyright (c) 2015-2016 Vladimir Kondratyev <wulf@cicgroup.ru>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include "opt_evdev.h"
#include <sys/types.h>
#include <sys/bitstring.h>
#include <sys/systm.h>
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/conf.h>
#include <sys/uio.h>
#include <sys/proc.h>
#include <sys/poll.h>
#include <sys/filio.h>
#include <sys/fcntl.h>
#include <sys/selinfo.h>
#include <sys/malloc.h>
#include <sys/time.h>
#include <dev/evdev/input.h>
#include <dev/evdev/evdev.h>
#include <dev/evdev/evdev_private.h>
#ifdef EVDEV_DEBUG
#define debugf(client, fmt, args...) printf("evdev cdev: "fmt"\n", ##args)
#else
#define debugf(client, fmt, args...)
#endif
#define DEF_RING_REPORTS 8
static d_open_t evdev_open;
static d_read_t evdev_read;
static d_write_t evdev_write;
static d_ioctl_t evdev_ioctl;
static d_poll_t evdev_poll;
static d_kqfilter_t evdev_kqfilter;
static int evdev_kqread(struct knote *kn, long hint);
static void evdev_kqdetach(struct knote *kn);
static void evdev_dtor(void *);
static int evdev_ioctl_eviocgbit(struct evdev_dev *, int, int, caddr_t);
static void evdev_client_filter_queue(struct evdev_client *, uint16_t);
static struct cdevsw evdev_cdevsw = {
.d_version = D_VERSION,
.d_open = evdev_open,
.d_read = evdev_read,
.d_write = evdev_write,
.d_ioctl = evdev_ioctl,
.d_poll = evdev_poll,
.d_kqfilter = evdev_kqfilter,
.d_name = "evdev",
};
static struct filterops evdev_cdev_filterops = {
.f_isfd = 1,
.f_attach = NULL,
.f_detach = evdev_kqdetach,
.f_event = evdev_kqread,
};
static int
evdev_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
struct evdev_dev *evdev = dev->si_drv1;
struct evdev_client *client;
size_t buffer_size;
int ret;
if (evdev == NULL)
return (ENODEV);
/* Initialize client structure */
buffer_size = evdev->ev_report_size * DEF_RING_REPORTS;
client = malloc(offsetof(struct evdev_client, ec_buffer) +
sizeof(struct input_event) * buffer_size,
M_EVDEV, M_WAITOK | M_ZERO);
/* Initialize ring buffer */
client->ec_buffer_size = buffer_size;
client->ec_buffer_head = 0;
client->ec_buffer_tail = 0;
client->ec_buffer_ready = 0;
client->ec_evdev = evdev;
mtx_init(&client->ec_buffer_mtx, "evclient", "evdev", MTX_DEF);
knlist_init_mtx(&client->ec_selp.si_note, &client->ec_buffer_mtx);
/* Avoid race with evdev_unregister */
EVDEV_LOCK(evdev);
if (dev->si_drv1 == NULL)
ret = ENODEV;
else
ret = evdev_register_client(evdev, client);
if (ret != 0)
evdev_revoke_client(client);
/*
* Unlock evdev here because non-sleepable lock held
* while calling devfs_set_cdevpriv upsets WITNESS
*/
EVDEV_UNLOCK(evdev);
if (!ret)
ret = devfs_set_cdevpriv(client, evdev_dtor);
if (ret != 0) {
debugf(client, "cannot register evdev client");
evdev_dtor(client);
}
return (ret);
}
static void
evdev_dtor(void *data)
{
struct evdev_client *client = (struct evdev_client *)data;
EVDEV_LOCK(client->ec_evdev);
if (!client->ec_revoked)
evdev_dispose_client(client->ec_evdev, client);
EVDEV_UNLOCK(client->ec_evdev);
knlist_clear(&client->ec_selp.si_note, 0);
seldrain(&client->ec_selp);
knlist_destroy(&client->ec_selp.si_note);
funsetown(&client->ec_sigio);
mtx_destroy(&client->ec_buffer_mtx);
free(client, M_EVDEV);
}
static int
evdev_read(struct cdev *dev, struct uio *uio, int ioflag)
{
struct evdev_client *client;
struct input_event *event;
int ret = 0;
int remaining;
ret = devfs_get_cdevpriv((void **)&client);
if (ret != 0)
return (ret);
debugf(client, "read %zd bytes by thread %d", uio->uio_resid,
uio->uio_td->td_tid);
if (client->ec_revoked)
return (ENODEV);
/* Zero-sized reads are allowed for error checking */
if (uio->uio_resid != 0 && uio->uio_resid < sizeof(struct input_event))
return (EINVAL);
remaining = uio->uio_resid / sizeof(struct input_event);
EVDEV_CLIENT_LOCKQ(client);
if (EVDEV_CLIENT_EMPTYQ(client)) {
if (ioflag & O_NONBLOCK)
ret = EWOULDBLOCK;
else {
if (remaining != 0) {
client->ec_blocked = true;
ret = mtx_sleep(client, &client->ec_buffer_mtx,
PCATCH, "evread", 0);
}
}
}
while (ret == 0 && !EVDEV_CLIENT_EMPTYQ(client) && remaining > 0) {
event = &client->ec_buffer[client->ec_buffer_head];
client->ec_buffer_head =
(client->ec_buffer_head + 1) % client->ec_buffer_size;
remaining--;
EVDEV_CLIENT_UNLOCKQ(client);
ret = uiomove(event, sizeof(struct input_event), uio);
EVDEV_CLIENT_LOCKQ(client);
}
EVDEV_CLIENT_UNLOCKQ(client);
return (ret);
}
static int
evdev_write(struct cdev *dev, struct uio *uio, int ioflag)
{
struct evdev_dev *evdev = dev->si_drv1;
struct evdev_client *client;
struct input_event event;
int ret = 0;
ret = devfs_get_cdevpriv((void **)&client);
if (ret != 0)
return (ret);
debugf(client, "write %zd bytes by thread %d", uio->uio_resid,
uio->uio_td->td_tid);
if (client->ec_revoked || evdev == NULL)
return (ENODEV);
if (uio->uio_resid % sizeof(struct input_event) != 0) {
debugf(client, "write size not multiple of input_event size");
return (EINVAL);
}
while (uio->uio_resid > 0 && ret == 0) {
ret = uiomove(&event, sizeof(struct input_event), uio);
if (ret == 0)
ret = evdev_inject_event(evdev, event.type, event.code,
event.value);
}
return (ret);
}
static int
evdev_poll(struct cdev *dev, int events, struct thread *td)
{
struct evdev_client *client;
int ret;
int revents = 0;
ret = devfs_get_cdevpriv((void **)&client);
if (ret != 0)
return (POLLNVAL);
debugf(client, "poll by thread %d", td->td_tid);
if (client->ec_revoked)
return (POLLHUP);
if (events & (POLLIN | POLLRDNORM)) {
EVDEV_CLIENT_LOCKQ(client);
if (!EVDEV_CLIENT_EMPTYQ(client))
revents = events & (POLLIN | POLLRDNORM);
else {
client->ec_selected = true;
selrecord(td, &client->ec_selp);
}
EVDEV_CLIENT_UNLOCKQ(client);
}
return (revents);
}
static int
evdev_kqfilter(struct cdev *dev, struct knote *kn)
{
struct evdev_client *client;
int ret;
ret = devfs_get_cdevpriv((void **)&client);
if (ret != 0)
return (ret);
if (client->ec_revoked)
return (ENODEV);
switch(kn->kn_filter) {
case EVFILT_READ:
kn->kn_fop = &evdev_cdev_filterops;
break;
default:
return(EINVAL);
}
kn->kn_hook = (caddr_t)client;
knlist_add(&client->ec_selp.si_note, kn, 0);
return (0);
}
static int
evdev_kqread(struct knote *kn, long hint)
{
struct evdev_client *client;
int ret;
client = (struct evdev_client *)kn->kn_hook;
EVDEV_CLIENT_LOCKQ_ASSERT(client);
if (client->ec_revoked) {
kn->kn_flags |= EV_EOF;
ret = 1;
} else {
kn->kn_data = EVDEV_CLIENT_SIZEQ(client) *
sizeof(struct input_event);
ret = !EVDEV_CLIENT_EMPTYQ(client);
}
return (ret);
}
static void
evdev_kqdetach(struct knote *kn)
{
struct evdev_client *client;
client = (struct evdev_client *)kn->kn_hook;
knlist_remove(&client->ec_selp.si_note, kn, 0);
}
static int
evdev_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag,
struct thread *td)
{
struct evdev_dev *evdev = dev->si_drv1;
struct evdev_client *client;
struct input_keymap_entry *ke;
int ret, len, limit, type_num;
uint32_t code;
size_t nvalues;
ret = devfs_get_cdevpriv((void **)&client);
if (ret != 0)
return (ret);
if (client->ec_revoked || evdev == NULL)
return (ENODEV);
/* file I/O ioctl handling */
switch (cmd) {
case FIOSETOWN:
return (fsetown(*(int *)data, &client->ec_sigio));
case FIOGETOWN:
*(int *)data = fgetown(&client->ec_sigio);
return (0);
case FIONBIO:
return (0);
case FIOASYNC:
if (*(int *)data)
client->ec_async = true;
else
client->ec_async = false;
return (0);
case FIONREAD:
EVDEV_CLIENT_LOCKQ(client);
*(int *)data =
EVDEV_CLIENT_SIZEQ(client) * sizeof(struct input_event);
EVDEV_CLIENT_UNLOCKQ(client);
return (0);
}
len = IOCPARM_LEN(cmd);
debugf(client, "ioctl called: cmd=0x%08lx, data=%p", cmd, data);
/* evdev fixed-length ioctls handling */
switch (cmd) {
case EVIOCGVERSION:
*(int *)data = EV_VERSION;
return (0);
case EVIOCGID:
debugf(client, "EVIOCGID: bus=%d vendor=0x%04x product=0x%04x",
evdev->ev_id.bustype, evdev->ev_id.vendor,
evdev->ev_id.product);
memcpy(data, &evdev->ev_id, sizeof(struct input_id));
return (0);
case EVIOCGREP:
if (!evdev_event_supported(evdev, EV_REP))
return (ENOTSUP);
memcpy(data, evdev->ev_rep, sizeof(evdev->ev_rep));
return (0);
case EVIOCSREP:
if (!evdev_event_supported(evdev, EV_REP))
return (ENOTSUP);
evdev_inject_event(evdev, EV_REP, REP_DELAY, ((int *)data)[0]);
evdev_inject_event(evdev, EV_REP, REP_PERIOD,
((int *)data)[1]);
return (0);
case EVIOCGKEYCODE:
/* Fake unsupported ioctl */
return (0);
case EVIOCGKEYCODE_V2:
if (evdev->ev_methods == NULL ||
evdev->ev_methods->ev_get_keycode == NULL)
return (ENOTSUP);
ke = (struct input_keymap_entry *)data;
evdev->ev_methods->ev_get_keycode(evdev, evdev->ev_softc, ke);
return (0);
case EVIOCSKEYCODE:
/* Fake unsupported ioctl */
return (0);
case EVIOCSKEYCODE_V2:
if (evdev->ev_methods == NULL ||
evdev->ev_methods->ev_set_keycode == NULL)
return (ENOTSUP);
ke = (struct input_keymap_entry *)data;
evdev->ev_methods->ev_set_keycode(evdev, evdev->ev_softc, ke);
return (0);
case EVIOCGABS(0) ... EVIOCGABS(ABS_MAX):
if (evdev->ev_absinfo == NULL)
return (EINVAL);
memcpy(data, &evdev->ev_absinfo[cmd - EVIOCGABS(0)],
sizeof(struct input_absinfo));
return (0);
case EVIOCSABS(0) ... EVIOCSABS(ABS_MAX):
if (evdev->ev_absinfo == NULL)
return (EINVAL);
code = cmd - EVIOCSABS(0);
/* mt-slot number can not be changed */
if (code == ABS_MT_SLOT)
return (EINVAL);
EVDEV_LOCK(evdev);
evdev_set_absinfo(evdev, code, (struct input_absinfo *)data);
EVDEV_UNLOCK(evdev);
return (0);
case EVIOCSFF:
case EVIOCRMFF:
case EVIOCGEFFECTS:
/* Fake unsupported ioctls */
return (0);
case EVIOCGRAB:
EVDEV_LOCK(evdev);
if (*(int *)data)
ret = evdev_grab_client(evdev, client);
else
ret = evdev_release_client(evdev, client);
EVDEV_UNLOCK(evdev);
return (ret);
case EVIOCREVOKE:
if (*(int *)data != 0)
return (EINVAL);
EVDEV_LOCK(evdev);
if (dev->si_drv1 != NULL && !client->ec_revoked) {
evdev_dispose_client(evdev, client);
evdev_revoke_client(client);
}
EVDEV_UNLOCK(evdev);
return (0);
case EVIOCSCLOCKID:
switch (*(int *)data) {
case CLOCK_REALTIME:
client->ec_clock_id = EV_CLOCK_REALTIME;
return (0);
case CLOCK_MONOTONIC:
client->ec_clock_id = EV_CLOCK_MONOTONIC;
return (0);
default:
return (EINVAL);
}
}
/* evdev variable-length ioctls handling */
switch (IOCBASECMD(cmd)) {
case EVIOCGNAME(0):
strlcpy(data, evdev->ev_name, len);
return (0);
case EVIOCGPHYS(0):
if (evdev->ev_shortname[0] == 0)
return (ENOENT);
strlcpy(data, evdev->ev_shortname, len);
return (0);
case EVIOCGUNIQ(0):
if (evdev->ev_serial[0] == 0)
return (ENOENT);
strlcpy(data, evdev->ev_serial, len);
return (0);
case EVIOCGPROP(0):
limit = MIN(len, bitstr_size(INPUT_PROP_CNT));
memcpy(data, evdev->ev_prop_flags, limit);
return (0);
case EVIOCGMTSLOTS(0):
if (evdev->ev_mt == NULL)
return (EINVAL);
if (len < sizeof(uint32_t))
return (EINVAL);
code = *(uint32_t *)data;
if (!ABS_IS_MT(code))
return (EINVAL);
nvalues =
MIN(len / sizeof(int32_t) - 1, MAXIMAL_MT_SLOT(evdev) + 1);
for (int i = 0; i < nvalues; i++)
((int32_t *)data)[i + 1] =
evdev_get_mt_value(evdev, i, code);
return (0);
case EVIOCGKEY(0):
limit = MIN(len, bitstr_size(KEY_CNT));
EVDEV_LOCK(evdev);
evdev_client_filter_queue(client, EV_KEY);
memcpy(data, evdev->ev_key_states, limit);
EVDEV_UNLOCK(evdev);
return (0);
case EVIOCGLED(0):
limit = MIN(len, bitstr_size(LED_CNT));
EVDEV_LOCK(evdev);
evdev_client_filter_queue(client, EV_LED);
memcpy(data, evdev->ev_led_states, limit);
EVDEV_UNLOCK(evdev);
return (0);
case EVIOCGSND(0):
limit = MIN(len, bitstr_size(SND_CNT));
EVDEV_LOCK(evdev);
evdev_client_filter_queue(client, EV_SND);
memcpy(data, evdev->ev_snd_states, limit);
EVDEV_UNLOCK(evdev);
return (0);
case EVIOCGSW(0):
limit = MIN(len, bitstr_size(SW_CNT));
EVDEV_LOCK(evdev);
evdev_client_filter_queue(client, EV_SW);
memcpy(data, evdev->ev_sw_states, limit);
EVDEV_UNLOCK(evdev);
return (0);
case EVIOCGBIT(0, 0) ... EVIOCGBIT(EV_MAX, 0):
type_num = IOCBASECMD(cmd) - EVIOCGBIT(0, 0);
debugf(client, "EVIOCGBIT(%d): data=%p, len=%d", type_num,
data, len);
return (evdev_ioctl_eviocgbit(evdev, type_num, len, data));
}
return (EINVAL);
}
static int
evdev_ioctl_eviocgbit(struct evdev_dev *evdev, int type, int len, caddr_t data)
{
unsigned long *bitmap;
int limit;
switch (type) {
case 0:
bitmap = evdev->ev_type_flags;
limit = EV_CNT;
break;
case EV_KEY:
bitmap = evdev->ev_key_flags;
limit = KEY_CNT;
break;
case EV_REL:
bitmap = evdev->ev_rel_flags;
limit = REL_CNT;
break;
case EV_ABS:
bitmap = evdev->ev_abs_flags;
limit = ABS_CNT;
break;
case EV_MSC:
bitmap = evdev->ev_msc_flags;
limit = MSC_CNT;
break;
case EV_LED:
bitmap = evdev->ev_led_flags;
limit = LED_CNT;
break;
case EV_SND:
bitmap = evdev->ev_snd_flags;
limit = SND_CNT;
break;
case EV_SW:
bitmap = evdev->ev_sw_flags;
limit = SW_CNT;
break;
case EV_FF:
/*
* We don't support EV_FF now, so let's
* just fake it returning only zeros.
*/
bzero(data, len);
return (0);
default:
return (ENOTTY);
}
/*
* Clear ioctl data buffer in case it's bigger than
* bitmap size
*/
bzero(data, len);
limit = bitstr_size(limit);
len = MIN(limit, len);
memcpy(data, bitmap, len);
return (0);
}
void
evdev_revoke_client(struct evdev_client *client)
{
EVDEV_LOCK_ASSERT(client->ec_evdev);
client->ec_revoked = true;
}
void
evdev_notify_event(struct evdev_client *client)
{
EVDEV_CLIENT_LOCKQ_ASSERT(client);
if (client->ec_blocked) {
client->ec_blocked = false;
wakeup(client);
}
if (client->ec_selected) {
client->ec_selected = false;
selwakeup(&client->ec_selp);
}
KNOTE_LOCKED(&client->ec_selp.si_note, 0);
if (client->ec_async && client->ec_sigio != NULL)
pgsigio(&client->ec_sigio, SIGIO, 0);
}
int
evdev_cdev_create(struct evdev_dev *evdev)
{
struct make_dev_args mda;
int ret, unit = 0;
make_dev_args_init(&mda);
mda.mda_flags = MAKEDEV_WAITOK | MAKEDEV_CHECKNAME;
mda.mda_devsw = &evdev_cdevsw;
mda.mda_uid = UID_ROOT;
mda.mda_gid = GID_WHEEL;
mda.mda_mode = 0600;
mda.mda_si_drv1 = evdev;
/* Try to coexist with cuse-backed input/event devices */
while ((ret = make_dev_s(&mda, &evdev->ev_cdev, "input/event%d", unit))
== EEXIST)
unit++;
if (ret == 0)
evdev->ev_unit = unit;
return (ret);
}
int
evdev_cdev_destroy(struct evdev_dev *evdev)
{
destroy_dev(evdev->ev_cdev);
return (0);
}
static void
evdev_client_gettime(struct evdev_client *client, struct timeval *tv)
{
switch (client->ec_clock_id) {
case EV_CLOCK_BOOTTIME:
/*
* XXX: FreeBSD does not support true POSIX monotonic clock.
* So aliase EV_CLOCK_BOOTTIME to EV_CLOCK_MONOTONIC.
*/
case EV_CLOCK_MONOTONIC:
microuptime(tv);
break;
case EV_CLOCK_REALTIME:
default:
microtime(tv);
break;
}
}
void
evdev_client_push(struct evdev_client *client, uint16_t type, uint16_t code,
int32_t value)
{
struct timeval time;
size_t count, head, tail, ready;
EVDEV_CLIENT_LOCKQ_ASSERT(client);
head = client->ec_buffer_head;
tail = client->ec_buffer_tail;
ready = client->ec_buffer_ready;
count = client->ec_buffer_size;
/* If queue is full drop its content and place SYN_DROPPED event */
if ((tail + 1) % count == head) {
debugf(client, "client %p: buffer overflow", client);
head = (tail + count - 1) % count;
client->ec_buffer[head] = (struct input_event) {
.type = EV_SYN,
.code = SYN_DROPPED,
.value = 0
};
/*
* XXX: Here is a small race window from now till the end of
* report. The queue is empty but client has been already
* notified of data readyness. Can be fixed in two ways:
* 1. Implement bulk insert so queue lock would not be dropped
* till the SYN_REPORT event.
* 2. Insert SYN_REPORT just now and skip remaining events
*/
client->ec_buffer_head = head;
client->ec_buffer_ready = head;
}
client->ec_buffer[tail].type = type;
client->ec_buffer[tail].code = code;
client->ec_buffer[tail].value = value;
client->ec_buffer_tail = (tail + 1) % count;
/* Allow users to read events only after report has been completed */
if (type == EV_SYN && code == SYN_REPORT) {
evdev_client_gettime(client, &time);
for (; ready != client->ec_buffer_tail;
ready = (ready + 1) % count)
client->ec_buffer[ready].time = time;
client->ec_buffer_ready = client->ec_buffer_tail;
}
}
void
evdev_client_dumpqueue(struct evdev_client *client)
{
struct input_event *event;
size_t i, head, tail, ready, size;
head = client->ec_buffer_head;
tail = client->ec_buffer_tail;
ready = client->ec_buffer_ready;
size = client->ec_buffer_size;
printf("evdev client: %p\n", client);
printf("event queue: head=%zu ready=%zu tail=%zu size=%zu\n",
head, ready, tail, size);
printf("queue contents:\n");
for (i = 0; i < size; i++) {
event = &client->ec_buffer[i];
printf("%zu: ", i);
if (i < head || i > tail)
printf("unused\n");
else
printf("type=%d code=%d value=%d ", event->type,
event->code, event->value);
if (i == head)
printf("<- head\n");
else if (i == tail)
printf("<- tail\n");
else if (i == ready)
printf("<- ready\n");
else
printf("\n");
}
}
static void
evdev_client_filter_queue(struct evdev_client *client, uint16_t type)
{
struct input_event *event;
size_t head, tail, count, i;
bool last_was_syn = false;
EVDEV_CLIENT_LOCKQ(client);
i = head = client->ec_buffer_head;
tail = client->ec_buffer_tail;
count = client->ec_buffer_size;
client->ec_buffer_ready = client->ec_buffer_tail;
while (i != client->ec_buffer_tail) {
event = &client->ec_buffer[i];
i = (i + 1) % count;
/* Skip event of given type */
if (event->type == type)
continue;
/* Remove empty SYN_REPORT events */
if (event->type == EV_SYN && event->code == SYN_REPORT) {
if (last_was_syn)
continue;
else
client->ec_buffer_ready = (tail + 1) % count;
}
/* Rewrite entry */
memcpy(&client->ec_buffer[tail], event,
sizeof(struct input_event));
last_was_syn = (event->type == EV_SYN &&
event->code == SYN_REPORT);
tail = (tail + 1) % count;
}
client->ec_buffer_head = i;
client->ec_buffer_tail = tail;
EVDEV_CLIENT_UNLOCKQ(client);
}