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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin dragonfly freebsd netbsd openbsd
package runtime
// Integrated network poller (kqueue-based implementation).
import "unsafe"
//extern kqueue
func kqueue() int32
//go:noescape
//extern kevent
func kevent(kq int32, ch *keventt, nch uintptr, ev *keventt, nev uintptr, ts *timespec) int32
//extern __go_fcntl_uintptr
func fcntlUintptr(fd, cmd, arg uintptr) (uintptr, uintptr)
func closeonexec(fd int32) {
fcntlUintptr(uintptr(fd), _F_SETFD, _FD_CLOEXEC)
}
var (
kq int32 = -1
)
func netpollinit() {
kq = kqueue()
if kq < 0 {
println("netpollinit: kqueue failed with", errno())
throw("netpollinit: kqueue failed")
}
closeonexec(kq)
}
func netpollopen(fd uintptr, pd *pollDesc) int32 {
// Arm both EVFILT_READ and EVFILT_WRITE in edge-triggered mode (EV_CLEAR)
// for the whole fd lifetime. The notifications are automatically unregistered
// when fd is closed.
var ev [2]keventt
*(*uintptr)(unsafe.Pointer(&ev[0].ident)) = fd
ev[0].filter = _EVFILT_READ
ev[0].flags = _EV_ADD | _EV_CLEAR
ev[0].fflags = 0
ev[0].data = 0
ev[0].udata = (*byte)(unsafe.Pointer(pd))
ev[1] = ev[0]
ev[1].filter = _EVFILT_WRITE
n := kevent(kq, &ev[0], 2, nil, 0, nil)
if n < 0 {
return int32(errno())
}
return 0
}
func netpollclose(fd uintptr) int32 {
// Don't need to unregister because calling close()
// on fd will remove any kevents that reference the descriptor.
return 0
}
func netpollarm(pd *pollDesc, mode int) {
throw("unused")
}
// Polls for ready network connections.
// Returns list of goroutines that become runnable.
func netpoll(block bool) *g {
if kq == -1 {
return nil
}
var tp *timespec
var ts timespec
if !block {
tp = &ts
}
var events [64]keventt
retry:
n := kevent(kq, nil, 0, &events[0], uintptr(len(events)), tp)
if n < 0 {
e := errno()
if e != _EINTR {
println("runtime: kevent on fd", kq, "failed with", e)
throw("kevent failed")
}
goto retry
}
var gp guintptr
for i := 0; i < int(n); i++ {
ev := &events[i]
var mode int32
if ev.filter == _EVFILT_READ {
mode += 'r'
}
if ev.filter == _EVFILT_WRITE {
mode += 'w'
}
if mode != 0 {
netpollready(&gp, (*pollDesc)(unsafe.Pointer(ev.udata)), mode)
}
}
if block && gp == 0 {
goto retry
}
return gp.ptr()
}
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