/*- * Copyright (c) 2014 Jakub Wojciech Klama * Copyright (c) 2015-2016 Vladimir Kondratyev * 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. */ #include "opt_evdev.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef COMPAT_FREEBSD32 #include #include #include struct input_event32 { struct timeval32 time; uint16_t type; uint16_t code; int32_t value; }; #endif #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, struct thread *); 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); ret = EVDEV_LIST_LOCK_SIG(evdev); if (ret != 0) goto out; /* Avoid race with evdev_unregister */ if (dev->si_drv1 == NULL) ret = ENODEV; else ret = evdev_register_client(evdev, client); EVDEV_LIST_UNLOCK(evdev); out: if (ret == 0) ret = devfs_set_cdevpriv(client, evdev_dtor); else client->ec_revoked = true; 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_LIST_LOCK(client->ec_evdev); if (!client->ec_revoked) evdev_dispose_client(client->ec_evdev, client); EVDEV_LIST_UNLOCK(client->ec_evdev); if (client->ec_evdev->ev_lock_type != EV_LOCK_MTX) epoch_wait_preempt(INPUT_EPOCH); 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; union { struct input_event t; #ifdef COMPAT_FREEBSD32 struct input_event32 t32; #endif } event; struct input_event *head; size_t evsize; 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); #ifdef COMPAT_FREEBSD32 if (SV_CURPROC_FLAG(SV_ILP32)) evsize = sizeof(struct input_event32); else #endif evsize = sizeof(struct input_event); /* Zero-sized reads are allowed for error checking */ if (uio->uio_resid != 0 && uio->uio_resid < evsize) return (EINVAL); remaining = uio->uio_resid / evsize; 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); if (ret == 0 && client->ec_revoked) ret = ENODEV; } } } while (ret == 0 && !EVDEV_CLIENT_EMPTYQ(client) && remaining > 0) { head = client->ec_buffer + client->ec_buffer_head; #ifdef COMPAT_FREEBSD32 if (SV_CURPROC_FLAG(SV_ILP32)) { bzero(&event.t32, sizeof(struct input_event32)); TV_CP(*head, event.t32, time); CP(*head, event.t32, type); CP(*head, event.t32, code); CP(*head, event.t32, value); } else #endif bcopy(head, &event.t, evsize); client->ec_buffer_head = (client->ec_buffer_head + 1) % client->ec_buffer_size; remaining--; EVDEV_CLIENT_UNLOCKQ(client); ret = uiomove(&event, evsize, 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; union { struct input_event t; #ifdef COMPAT_FREEBSD32 struct input_event32 t32; #endif } event; size_t evsize; 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); #ifdef COMPAT_FREEBSD32 if (SV_CURPROC_FLAG(SV_ILP32)) evsize = sizeof(struct input_event32); else #endif evsize = sizeof(struct input_event); if (uio->uio_resid % evsize != 0) { debugf(client, "write size not multiple of input_event size"); return (EINVAL); } while (uio->uio_resid > 0 && ret == 0) { ret = uiomove(&event, evsize, uio); if (ret == 0) { #ifdef COMPAT_FREEBSD32 if (SV_CURPROC_FLAG(SV_ILP32)) ret = evdev_inject_event(evdev, event.t32.type, event.t32.code, event.t32.value); else #endif ret = evdev_inject_event(evdev, event.t.type, event.t.code, event.t.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; struct epoch_tracker et; 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); /* * Fix evdev state corrupted with discarding of kdb events. * EVIOCGKEY and EVIOCGLED ioctls can suffer from this. */ if (evdev->ev_kdb_active) { EVDEV_LOCK(evdev); if (evdev->ev_kdb_active) { evdev->ev_kdb_active = false; if (evdev->ev_lock_type == EV_LOCK_EXT_EPOCH) epoch_enter_preempt(INPUT_EPOCH, &et); evdev_restore_after_kdb(evdev); if (evdev->ev_lock_type == EV_LOCK_EXT_EPOCH) epoch_exit_preempt(INPUT_EPOCH, &et); } EVDEV_UNLOCK(evdev); } /* 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, 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, 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_LIST_LOCK(evdev); if (dev->si_drv1 != NULL && !client->ec_revoked) { evdev_dispose_client(evdev, client); evdev_revoke_client(client); } EVDEV_LIST_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): /* Linux evdev does not terminate truncated strings with 0 */ limit = MIN(strlen(evdev->ev_name) + 1, len); memcpy(data, evdev->ev_name, limit); td->td_retval[0] = limit; return (0); case EVIOCGPHYS(0): if (evdev->ev_shortname[0] == 0) return (ENOENT); limit = MIN(strlen(evdev->ev_shortname) + 1, len); memcpy(data, evdev->ev_shortname, limit); td->td_retval[0] = limit; return (0); case EVIOCGUNIQ(0): if (evdev->ev_serial[0] == 0) return (ENOENT); limit = MIN(strlen(evdev->ev_serial) + 1, len); memcpy(data, evdev->ev_serial, limit); td->td_retval[0] = limit; return (0); case EVIOCGPROP(0): limit = MIN(len, bitstr_size(INPUT_PROP_CNT)); memcpy(data, evdev->ev_prop_flags, limit); td->td_retval[0] = limit; return (0); case EVIOCGMTSLOTS(0): /* EVIOCGMTSLOTS always returns 0 on success */ 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_mt_get_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); td->td_retval[0] = limit; 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); td->td_retval[0] = limit; 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); td->td_retval[0] = limit; 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); td->td_retval[0] = limit; 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, td)); } return (EINVAL); } static int evdev_ioctl_eviocgbit(struct evdev_dev *evdev, int type, int len, caddr_t data, struct thread *td) { 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); td->td_retval[0] = 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); td->td_retval[0] = len; return (0); } void evdev_revoke_client(struct evdev_client *client) { EVDEV_LIST_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); }