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nxt_epoll_engine.c
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/*
* Copyright (C) Igor Sysoev
* Copyright (C) NGINX, Inc.
*/
#include <nxt_main.h>
/*
* The first epoll version has been introduced in Linux 2.5.44. The
* interface was changed several times since then and the final version
* of epoll_create(), epoll_ctl(), epoll_wait(), and EPOLLET mode has
* been introduced in Linux 2.6.0 and is supported since glibc 2.3.2.
*
* EPOLLET mode did not work reliable in early implementaions and in
* Linux 2.4 backport.
*
* EPOLLONESHOT Linux 2.6.2, glibc 2.3.
* EPOLLRDHUP Linux 2.6.17, glibc 2.8.
* epoll_pwait() Linux 2.6.19, glibc 2.6.
* signalfd() Linux 2.6.22, glibc 2.7.
* eventfd() Linux 2.6.22, glibc 2.7.
* timerfd_create() Linux 2.6.25, glibc 2.8.
* epoll_create1() Linux 2.6.27, glibc 2.9.
* signalfd4() Linux 2.6.27, glibc 2.9.
* eventfd2() Linux 2.6.27, glibc 2.9.
* accept4() Linux 2.6.28, glibc 2.10.
* eventfd2(EFD_SEMAPHORE) Linux 2.6.30, glibc 2.10.
* EPOLLEXCLUSIVE Linux 4.5, glibc 2.24.
*/
#if (NXT_HAVE_EPOLL_EDGE)
static nxt_int_t nxt_epoll_edge_create(nxt_event_engine_t *engine,
nxt_uint_t mchanges, nxt_uint_t mevents);
#endif
static nxt_int_t nxt_epoll_level_create(nxt_event_engine_t *engine,
nxt_uint_t mchanges, nxt_uint_t mevents);
static nxt_int_t nxt_epoll_create(nxt_event_engine_t *engine,
nxt_uint_t mchanges, nxt_uint_t mevents, nxt_conn_io_t *io, uint32_t mode);
static void nxt_epoll_test_accept4(nxt_event_engine_t *engine,
nxt_conn_io_t *io);
static void nxt_epoll_free(nxt_event_engine_t *engine);
static void nxt_epoll_enable(nxt_event_engine_t *engine, nxt_fd_event_t *ev);
static void nxt_epoll_disable(nxt_event_engine_t *engine, nxt_fd_event_t *ev);
static void nxt_epoll_delete(nxt_event_engine_t *engine, nxt_fd_event_t *ev);
static nxt_bool_t nxt_epoll_close(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_enable_read(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_enable_write(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_disable_read(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_disable_write(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_block_read(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_block_write(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_oneshot_read(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_oneshot_write(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_enable_accept(nxt_event_engine_t *engine,
nxt_fd_event_t *ev);
static void nxt_epoll_change(nxt_event_engine_t *engine, nxt_fd_event_t *ev,
int op, uint32_t events);
static void nxt_epoll_commit_changes(nxt_event_engine_t *engine);
static void nxt_epoll_error_handler(nxt_task_t *task, void *obj, void *data);
#if (NXT_HAVE_SIGNALFD)
static nxt_int_t nxt_epoll_add_signal(nxt_event_engine_t *engine);
static void nxt_epoll_signalfd_handler(nxt_task_t *task, void *obj, void *data);
#endif
#if (NXT_HAVE_EVENTFD)
static nxt_int_t nxt_epoll_enable_post(nxt_event_engine_t *engine,
nxt_work_handler_t handler);
static void nxt_epoll_eventfd_handler(nxt_task_t *task, void *obj, void *data);
static void nxt_epoll_signal(nxt_event_engine_t *engine, nxt_uint_t signo);
#endif
static void nxt_epoll_poll(nxt_event_engine_t *engine, nxt_msec_t timeout);
#if (NXT_HAVE_ACCEPT4)
static void nxt_epoll_conn_io_accept4(nxt_task_t *task, void *obj,
void *data);
#endif
#if (NXT_HAVE_EPOLL_EDGE)
static void nxt_epoll_edge_conn_io_connect(nxt_task_t *task, void *obj,
void *data);
static void nxt_epoll_edge_conn_connected(nxt_task_t *task, void *obj,
void *data);
static ssize_t nxt_epoll_edge_conn_io_recvbuf(nxt_conn_t *c, nxt_buf_t *b);
static nxt_conn_io_t nxt_epoll_edge_conn_io = {
.connect = nxt_epoll_edge_conn_io_connect,
.accept = nxt_conn_io_accept,
.read = nxt_conn_io_read,
.recvbuf = nxt_epoll_edge_conn_io_recvbuf,
.recv = nxt_conn_io_recv,
.write = nxt_conn_io_write,
.sendbuf = nxt_conn_io_sendbuf,
#if (NXT_HAVE_LINUX_SENDFILE)
.old_sendbuf = nxt_linux_event_conn_io_sendfile,
#else
.old_sendbuf = nxt_event_conn_io_sendbuf,
#endif
.writev = nxt_event_conn_io_writev,
.send = nxt_event_conn_io_send,
};
const nxt_event_interface_t nxt_epoll_edge_engine = {
"epoll_edge",
nxt_epoll_edge_create,
nxt_epoll_free,
nxt_epoll_enable,
nxt_epoll_disable,
nxt_epoll_delete,
nxt_epoll_close,
nxt_epoll_enable_read,
nxt_epoll_enable_write,
nxt_epoll_disable_read,
nxt_epoll_disable_write,
nxt_epoll_block_read,
nxt_epoll_block_write,
nxt_epoll_oneshot_read,
nxt_epoll_oneshot_write,
nxt_epoll_enable_accept,
NULL,
NULL,
#if (NXT_HAVE_EVENTFD)
nxt_epoll_enable_post,
nxt_epoll_signal,
#else
NULL,
NULL,
#endif
nxt_epoll_poll,
&nxt_epoll_edge_conn_io,
#if (NXT_HAVE_INOTIFY)
NXT_FILE_EVENTS,
#else
NXT_NO_FILE_EVENTS,
#endif
#if (NXT_HAVE_SIGNALFD)
NXT_SIGNAL_EVENTS,
#else
NXT_NO_SIGNAL_EVENTS,
#endif
};
#endif
const nxt_event_interface_t nxt_epoll_level_engine = {
"epoll_level",
nxt_epoll_level_create,
nxt_epoll_free,
nxt_epoll_enable,
nxt_epoll_disable,
nxt_epoll_delete,
nxt_epoll_close,
nxt_epoll_enable_read,
nxt_epoll_enable_write,
nxt_epoll_disable_read,
nxt_epoll_disable_write,
nxt_epoll_block_read,
nxt_epoll_block_write,
nxt_epoll_oneshot_read,
nxt_epoll_oneshot_write,
nxt_epoll_enable_accept,
NULL,
NULL,
#if (NXT_HAVE_EVENTFD)
nxt_epoll_enable_post,
nxt_epoll_signal,
#else
NULL,
NULL,
#endif
nxt_epoll_poll,
&nxt_unix_conn_io,
#if (NXT_HAVE_INOTIFY)
NXT_FILE_EVENTS,
#else
NXT_NO_FILE_EVENTS,
#endif
#if (NXT_HAVE_SIGNALFD)
NXT_SIGNAL_EVENTS,
#else
NXT_NO_SIGNAL_EVENTS,
#endif
};
#if (NXT_HAVE_EPOLL_EDGE)
static nxt_int_t
nxt_epoll_edge_create(nxt_event_engine_t *engine, nxt_uint_t mchanges,
nxt_uint_t mevents)
{
return nxt_epoll_create(engine, mchanges, mevents, &nxt_epoll_edge_conn_io,
EPOLLET | EPOLLRDHUP);
}
#endif
static nxt_int_t
nxt_epoll_level_create(nxt_event_engine_t *engine, nxt_uint_t mchanges,
nxt_uint_t mevents)
{
return nxt_epoll_create(engine, mchanges, mevents,
&nxt_unix_conn_io, 0);
}
static nxt_int_t
nxt_epoll_create(nxt_event_engine_t *engine, nxt_uint_t mchanges,
nxt_uint_t mevents, nxt_conn_io_t *io, uint32_t mode)
{
engine->u.epoll.fd = -1;
engine->u.epoll.mode = mode;
engine->u.epoll.mchanges = mchanges;
engine->u.epoll.mevents = mevents;
#if (NXT_HAVE_SIGNALFD)
engine->u.epoll.signalfd.fd = -1;
#endif
engine->u.epoll.changes = nxt_malloc(sizeof(nxt_epoll_change_t) * mchanges);
if (engine->u.epoll.changes == NULL) {
goto fail;
}
engine->u.epoll.events = nxt_malloc(sizeof(struct epoll_event) * mevents);
if (engine->u.epoll.events == NULL) {
goto fail;
}
engine->u.epoll.fd = epoll_create(1);
if (engine->u.epoll.fd == -1) {
nxt_alert(&engine->task, "epoll_create() failed %E", nxt_errno);
goto fail;
}
nxt_debug(&engine->task, "epoll_create(): %d", engine->u.epoll.fd);
if (engine->signals != NULL) {
#if (NXT_HAVE_SIGNALFD)
if (nxt_epoll_add_signal(engine) != NXT_OK) {
goto fail;
}
#endif
nxt_epoll_test_accept4(engine, io);
}
return NXT_OK;
fail:
nxt_epoll_free(engine);
return NXT_ERROR;
}
static void
nxt_epoll_test_accept4(nxt_event_engine_t *engine, nxt_conn_io_t *io)
{
static nxt_work_handler_t handler;
if (handler == NULL) {
handler = io->accept;
#if (NXT_HAVE_ACCEPT4)
(void) accept4(-1, NULL, NULL, SOCK_NONBLOCK);
if (nxt_errno != NXT_ENOSYS) {
handler = nxt_epoll_conn_io_accept4;
} else {
nxt_log(&engine->task, NXT_LOG_INFO, "accept4() failed %E",
NXT_ENOSYS);
}
#endif
}
io->accept = handler;
}
static void
nxt_epoll_free(nxt_event_engine_t *engine)
{
int fd;
nxt_debug(&engine->task, "epoll %d free", engine->u.epoll.fd);
#if (NXT_HAVE_SIGNALFD)
fd = engine->u.epoll.signalfd.fd;
if (fd != -1 && close(fd) != 0) {
nxt_alert(&engine->task, "signalfd close(%d) failed %E", fd, nxt_errno);
}
#endif
#if (NXT_HAVE_EVENTFD)
fd = engine->u.epoll.eventfd.fd;
if (fd != -1 && close(fd) != 0) {
nxt_alert(&engine->task, "eventfd close(%d) failed %E", fd, nxt_errno);
}
#endif
fd = engine->u.epoll.fd;
if (fd != -1 && close(fd) != 0) {
nxt_alert(&engine->task, "epoll close(%d) failed %E", fd, nxt_errno);
}
nxt_free(engine->u.epoll.events);
nxt_free(engine->u.epoll.changes);
nxt_memzero(&engine->u.epoll, sizeof(nxt_epoll_engine_t));
}
static void
nxt_epoll_enable(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
ev->read = NXT_EVENT_ACTIVE;
ev->write = NXT_EVENT_ACTIVE;
nxt_epoll_change(engine, ev, EPOLL_CTL_ADD,
EPOLLIN | EPOLLOUT | engine->u.epoll.mode);
}
static void
nxt_epoll_disable(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
if (ev->read > NXT_EVENT_DISABLED || ev->write > NXT_EVENT_DISABLED) {
ev->read = NXT_EVENT_INACTIVE;
ev->write = NXT_EVENT_INACTIVE;
nxt_epoll_change(engine, ev, EPOLL_CTL_DEL, 0);
}
}
static void
nxt_epoll_delete(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
if (ev->read != NXT_EVENT_INACTIVE || ev->write != NXT_EVENT_INACTIVE) {
ev->read = NXT_EVENT_INACTIVE;
ev->write = NXT_EVENT_INACTIVE;
nxt_epoll_change(engine, ev, EPOLL_CTL_DEL, 0);
}
}
/*
* Although calling close() on a file descriptor will remove any epoll
* events that reference the descriptor, in this case the close() acquires
* the kernel global "epmutex" while epoll_ctl(EPOLL_CTL_DEL) does not
* acquire the "epmutex" since Linux 3.13 if the file descriptor presents
* only in one epoll set. Thus removing events explicitly before closing
* eliminates possible lock contention.
*/
static nxt_bool_t
nxt_epoll_close(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
nxt_epoll_delete(engine, ev);
return ev->changing;
}
static void
nxt_epoll_enable_read(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
int op;
uint32_t events;
if (ev->read != NXT_EVENT_BLOCKED) {
op = EPOLL_CTL_MOD;
events = EPOLLIN | engine->u.epoll.mode;
if (ev->read == NXT_EVENT_INACTIVE && ev->write == NXT_EVENT_INACTIVE) {
op = EPOLL_CTL_ADD;
} else if (ev->write >= NXT_EVENT_BLOCKED) {
events |= EPOLLOUT;
}
nxt_epoll_change(engine, ev, op, events);
}
ev->read = NXT_EVENT_ACTIVE;
}
static void
nxt_epoll_enable_write(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
int op;
uint32_t events;
if (ev->write != NXT_EVENT_BLOCKED) {
op = EPOLL_CTL_MOD;
events = EPOLLOUT | engine->u.epoll.mode;
if (ev->read == NXT_EVENT_INACTIVE && ev->write == NXT_EVENT_INACTIVE) {
op = EPOLL_CTL_ADD;
} else if (ev->read >= NXT_EVENT_BLOCKED) {
events |= EPOLLIN;
}
nxt_epoll_change(engine, ev, op, events);
}
ev->write = NXT_EVENT_ACTIVE;
}
static void
nxt_epoll_disable_read(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
int op;
uint32_t events;
ev->read = NXT_EVENT_INACTIVE;
if (ev->write <= NXT_EVENT_DISABLED) {
ev->write = NXT_EVENT_INACTIVE;
op = EPOLL_CTL_DEL;
events = 0;
} else {
op = EPOLL_CTL_MOD;
events = EPOLLOUT | engine->u.epoll.mode;
}
nxt_epoll_change(engine, ev, op, events);
}
static void
nxt_epoll_disable_write(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
int op;
uint32_t events;
ev->write = NXT_EVENT_INACTIVE;
if (ev->read <= NXT_EVENT_DISABLED) {
ev->read = NXT_EVENT_INACTIVE;
op = EPOLL_CTL_DEL;
events = 0;
} else {
op = EPOLL_CTL_MOD;
events = EPOLLIN | engine->u.epoll.mode;
}
nxt_epoll_change(engine, ev, op, events);
}
static void
nxt_epoll_block_read(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
if (ev->read != NXT_EVENT_INACTIVE) {
ev->read = NXT_EVENT_BLOCKED;
}
}
static void
nxt_epoll_block_write(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
if (ev->write != NXT_EVENT_INACTIVE) {
ev->write = NXT_EVENT_BLOCKED;
}
}
/*
* NXT_EVENT_DISABLED state is used to track whether EPOLLONESHOT
* event should be added or modified, epoll_ctl(2):
*
* EPOLLONESHOT (since Linux 2.6.2)
* Sets the one-shot behavior for the associated file descriptor.
* This means that after an event is pulled out with epoll_wait(2)
* the associated file descriptor is internally disabled and no
* other events will be reported by the epoll interface. The user
* must call epoll_ctl() with EPOLL_CTL_MOD to rearm the file
* descriptor with a new event mask.
*/
static void
nxt_epoll_oneshot_read(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
int op;
op = (ev->read == NXT_EVENT_INACTIVE && ev->write == NXT_EVENT_INACTIVE) ?
EPOLL_CTL_ADD : EPOLL_CTL_MOD;
ev->read = NXT_EVENT_ONESHOT;
ev->write = NXT_EVENT_INACTIVE;
nxt_epoll_change(engine, ev, op, EPOLLIN | EPOLLONESHOT);
}
static void
nxt_epoll_oneshot_write(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
int op;
op = (ev->read == NXT_EVENT_INACTIVE && ev->write == NXT_EVENT_INACTIVE) ?
EPOLL_CTL_ADD : EPOLL_CTL_MOD;
ev->read = NXT_EVENT_INACTIVE;
ev->write = NXT_EVENT_ONESHOT;
nxt_epoll_change(engine, ev, op, EPOLLOUT | EPOLLONESHOT);
}
static void
nxt_epoll_enable_accept(nxt_event_engine_t *engine, nxt_fd_event_t *ev)
{
uint32_t events;
ev->read = NXT_EVENT_ACTIVE;
events = EPOLLIN;
#ifdef EPOLLEXCLUSIVE
events |= EPOLLEXCLUSIVE;
#endif
nxt_epoll_change(engine, ev, EPOLL_CTL_ADD, events);
}
/*
* epoll changes are batched to improve instruction and data cache
* locality of several epoll_ctl() calls followed by epoll_wait() call.
*/
static void
nxt_epoll_change(nxt_event_engine_t *engine, nxt_fd_event_t *ev, int op,
uint32_t events)
{
nxt_epoll_change_t *change;
nxt_debug(ev->task, "epoll %d set event: fd:%d op:%d ev:%XD",
engine->u.epoll.fd, ev->fd, op, events);
if (engine->u.epoll.nchanges >= engine->u.epoll.mchanges) {
nxt_epoll_commit_changes(engine);
}
ev->changing = 1;
change = &engine->u.epoll.changes[engine->u.epoll.nchanges++];
change->op = op;
change->event.events = events;
change->event.data.ptr = ev;
}
static void
nxt_epoll_commit_changes(nxt_event_engine_t *engine)
{
int ret;
nxt_fd_event_t *ev;
nxt_epoll_change_t *change, *end;
nxt_debug(&engine->task, "epoll %d changes:%ui",
engine->u.epoll.fd, engine->u.epoll.nchanges);
change = engine->u.epoll.changes;
end = change + engine->u.epoll.nchanges;
do {
ev = change->event.data.ptr;
ev->changing = 0;
nxt_debug(ev->task, "epoll_ctl(%d): fd:%d op:%d ev:%XD",
engine->u.epoll.fd, ev->fd, change->op,
change->event.events);
ret = epoll_ctl(engine->u.epoll.fd, change->op, ev->fd, &change->event);
if (nxt_slow_path(ret != 0)) {
nxt_alert(ev->task, "epoll_ctl(%d, %d, %d) failed %E",
engine->u.epoll.fd, change->op, ev->fd, nxt_errno);
nxt_work_queue_add(&engine->fast_work_queue,
nxt_epoll_error_handler, ev->task, ev, ev->data);
engine->u.epoll.error = 1;
}
change++;
} while (change < end);
engine->u.epoll.nchanges = 0;
}
static void
nxt_epoll_error_handler(nxt_task_t *task, void *obj, void *data)
{
nxt_fd_event_t *ev;
ev = obj;
ev->read = NXT_EVENT_INACTIVE;
ev->write = NXT_EVENT_INACTIVE;
ev->error_handler(ev->task, ev, data);
}
#if (NXT_HAVE_SIGNALFD)
static nxt_int_t
nxt_epoll_add_signal(nxt_event_engine_t *engine)
{
int fd;
struct epoll_event ee;
if (sigprocmask(SIG_BLOCK, &engine->signals->sigmask, NULL) != 0) {
nxt_alert(&engine->task, "sigprocmask(SIG_BLOCK) failed %E", nxt_errno);
return NXT_ERROR;
}
/*
* Glibc signalfd() wrapper always has the flags argument. Glibc 2.7
* and 2.8 signalfd() wrappers call the original signalfd() syscall
* without the flags argument. Glibc 2.9+ signalfd() wrapper at first
* tries to call signalfd4() syscall and if it fails then calls the
* original signalfd() syscall. For this reason the non-blocking mode
* is set separately.
*/
fd = signalfd(-1, &engine->signals->sigmask, 0);
if (fd == -1) {
nxt_alert(&engine->task, "signalfd(%d) failed %E",
engine->u.epoll.signalfd.fd, nxt_errno);
return NXT_ERROR;
}
engine->u.epoll.signalfd.fd = fd;
if (nxt_fd_nonblocking(&engine->task, fd) != NXT_OK) {
return NXT_ERROR;
}
nxt_debug(&engine->task, "signalfd(): %d", fd);
engine->u.epoll.signalfd.data = engine->signals->handler;
engine->u.epoll.signalfd.read_work_queue = &engine->fast_work_queue;
engine->u.epoll.signalfd.read_handler = nxt_epoll_signalfd_handler;
engine->u.epoll.signalfd.log = engine->task.log;
engine->u.epoll.signalfd.task = &engine->task;
ee.events = EPOLLIN;
ee.data.ptr = &engine->u.epoll.signalfd;
if (epoll_ctl(engine->u.epoll.fd, EPOLL_CTL_ADD, fd, &ee) != 0) {
nxt_alert(&engine->task, "epoll_ctl(%d, %d, %d) failed %E",
engine->u.epoll.fd, EPOLL_CTL_ADD, fd, nxt_errno);
return NXT_ERROR;
}
return NXT_OK;
}
static void
nxt_epoll_signalfd_handler(nxt_task_t *task, void *obj, void *data)
{
int n;
nxt_fd_event_t *ev;
nxt_work_handler_t handler;
struct signalfd_siginfo sfd;
ev = obj;
handler = data;
nxt_debug(task, "signalfd handler");
n = read(ev->fd, &sfd, sizeof(struct signalfd_siginfo));
nxt_debug(task, "read signalfd(%d): %d", ev->fd, n);
if (n != sizeof(struct signalfd_siginfo)) {
nxt_alert(task, "read signalfd(%d) failed %E", ev->fd, nxt_errno);
return;
}
nxt_debug(task, "signalfd(%d) signo:%d", ev->fd, sfd.ssi_signo);
handler(task, (void *) (uintptr_t) sfd.ssi_signo, NULL);
}
#endif
#if (NXT_HAVE_EVENTFD)
static nxt_int_t
nxt_epoll_enable_post(nxt_event_engine_t *engine, nxt_work_handler_t handler)
{
int ret;
struct epoll_event ee;
engine->u.epoll.post_handler = handler;
/*
* Glibc eventfd() wrapper always has the flags argument. Glibc 2.7
* and 2.8 eventfd() wrappers call the original eventfd() syscall
* without the flags argument. Glibc 2.9+ eventfd() wrapper at first
* tries to call eventfd2() syscall and if it fails then calls the
* original eventfd() syscall. For this reason the non-blocking mode
* is set separately.
*/
engine->u.epoll.eventfd.fd = eventfd(0, 0);
if (engine->u.epoll.eventfd.fd == -1) {
nxt_alert(&engine->task, "eventfd() failed %E", nxt_errno);
return NXT_ERROR;
}
ret = nxt_fd_nonblocking(&engine->task, engine->u.epoll.eventfd.fd);
if (nxt_slow_path(ret != NXT_OK)) {
return NXT_ERROR;
}
nxt_debug(&engine->task, "eventfd(): %d", engine->u.epoll.eventfd.fd);
engine->u.epoll.eventfd.read_work_queue = &engine->fast_work_queue;
engine->u.epoll.eventfd.read_handler = nxt_epoll_eventfd_handler;
engine->u.epoll.eventfd.data = engine;
engine->u.epoll.eventfd.log = engine->task.log;
engine->u.epoll.eventfd.task = &engine->task;
ee.events = EPOLLIN | EPOLLET;
ee.data.ptr = &engine->u.epoll.eventfd;
ret = epoll_ctl(engine->u.epoll.fd, EPOLL_CTL_ADD,
engine->u.epoll.eventfd.fd, &ee);
if (nxt_fast_path(ret == 0)) {
return NXT_OK;
}
nxt_alert(&engine->task, "epoll_ctl(%d, %d, %d) failed %E",
engine->u.epoll.fd, EPOLL_CTL_ADD, engine->u.epoll.eventfd.fd,
nxt_errno);
return NXT_ERROR;
}
static void
nxt_epoll_eventfd_handler(nxt_task_t *task, void *obj, void *data)
{
int n;
uint64_t events;
nxt_event_engine_t *engine;
engine = data;
nxt_debug(task, "eventfd handler, times:%ui", engine->u.epoll.neventfd);
/*
* The maximum value after write() to a eventfd() descriptor will
* block or return EAGAIN is 0xFFFFFFFFFFFFFFFE, so the descriptor
* can be read once per many notifications, for example, once per
* 2^32-2 noticifcations. Since the eventfd() file descriptor is
* always registered in EPOLLET mode, epoll returns event about
* only the latest write() to the descriptor.
*/
if (engine->u.epoll.neventfd++ >= 0xFFFFFFFE) {
engine->u.epoll.neventfd = 0;
n = read(engine->u.epoll.eventfd.fd, &events, sizeof(uint64_t));
nxt_debug(task, "read(%d): %d events:%uL",
engine->u.epoll.eventfd.fd, n, events);
if (n != sizeof(uint64_t)) {
nxt_alert(task, "read eventfd(%d) failed %E",
engine->u.epoll.eventfd.fd, nxt_errno);
}
}
engine->u.epoll.post_handler(task, NULL, NULL);
}
static void
nxt_epoll_signal(nxt_event_engine_t *engine, nxt_uint_t signo)
{
size_t ret;
uint64_t event;
/*
* eventfd() presents along with signalfd(), so the function
* is used only to post events and the signo argument is ignored.
*/
event = 1;
ret = write(engine->u.epoll.eventfd.fd, &event, sizeof(uint64_t));
if (nxt_slow_path(ret != sizeof(uint64_t))) {
nxt_alert(&engine->task, "write(%d) to eventfd failed %E",
engine->u.epoll.eventfd.fd, nxt_errno);
}
}
#endif
static void
nxt_epoll_poll(nxt_event_engine_t *engine, nxt_msec_t timeout)
{
int nevents;
uint32_t events;
nxt_int_t i;
nxt_err_t err;
nxt_bool_t error;
nxt_uint_t level;
nxt_fd_event_t *ev;
struct epoll_event *event;
if (engine->u.epoll.nchanges != 0) {
nxt_epoll_commit_changes(engine);
}
if (engine->u.epoll.error) {
engine->u.epoll.error = 0;
/* Error handlers have been enqueued on failure. */
timeout = 0;
}
nxt_debug(&engine->task, "epoll_wait(%d) timeout:%M",
engine->u.epoll.fd, timeout);
nevents = epoll_wait(engine->u.epoll.fd, engine->u.epoll.events,
engine->u.epoll.mevents, timeout);
err = (nevents == -1) ? nxt_errno : 0;
nxt_thread_time_update(engine->task.thread);
nxt_debug(&engine->task, "epoll_wait(%d): %d", engine->u.epoll.fd, nevents);
if (nevents == -1) {
level = (err == NXT_EINTR) ? NXT_LOG_INFO : NXT_LOG_ALERT;
nxt_log(&engine->task, level, "epoll_wait(%d) failed %E",
engine->u.epoll.fd, err);
return;
}
for (i = 0; i < nevents; i++) {
event = &engine->u.epoll.events[i];
events = event->events;
ev = event->data.ptr;
nxt_debug(ev->task, "epoll: fd:%d ev:%04XD d:%p rd:%d wr:%d",
ev->fd, events, ev, ev->read, ev->write);
/*
* On error epoll may set EPOLLERR and EPOLLHUP only without EPOLLIN
* or EPOLLOUT, so the "error" variable enqueues only error handler.
*/
error = ((events & (EPOLLERR | EPOLLHUP)) != 0);
ev->epoll_error = error;
if (error
&& ev->read <= NXT_EVENT_BLOCKED
&& ev->write <= NXT_EVENT_BLOCKED)
{
error = 0;
}
#if (NXT_HAVE_EPOLL_EDGE)
ev->epoll_eof = ((events & EPOLLRDHUP) != 0);
#endif
if ((events & EPOLLIN) != 0) {
ev->read_ready = 1;
if (ev->read != NXT_EVENT_BLOCKED) {
if (ev->read == NXT_EVENT_ONESHOT) {
ev->read = NXT_EVENT_DISABLED;
}
nxt_work_queue_add(ev->read_work_queue, ev->read_handler,
ev->task, ev, ev->data);
error = 0;
} else if (engine->u.epoll.mode == 0) {
/* Level-triggered mode. */
nxt_epoll_disable_read(engine, ev);
}
}
if ((events & EPOLLOUT) != 0) {
ev->write_ready = 1;
if (ev->write != NXT_EVENT_BLOCKED) {
if (ev->write == NXT_EVENT_ONESHOT) {
ev->write = NXT_EVENT_DISABLED;
}
nxt_work_queue_add(ev->write_work_queue, ev->write_handler,
ev->task, ev, ev->data);
error = 0;
} else if (engine->u.epoll.mode == 0) {
/* Level-triggered mode. */
nxt_epoll_disable_write(engine, ev);
}
}
if (!error) {
continue;
}
ev->read_ready = 1;
ev->write_ready = 1;
if (ev->read == NXT_EVENT_BLOCKED && ev->write == NXT_EVENT_BLOCKED) {
if (engine->u.epoll.mode == 0) {
/* Level-triggered mode. */
nxt_epoll_disable(engine, ev);
}
continue;
}
nxt_work_queue_add(&engine->fast_work_queue, nxt_epoll_error_handler,
ev->task, ev, ev->data);