...
Run Format

Source file src/runtime/netpoll_kqueue.go

Documentation: runtime

  // 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"
  
  func kqueue() int32
  
  //go:noescape
  func kevent(kq int32, ch *keventt, nch int32, ev *keventt, nev int32, ts *timespec) int32
  func closeonexec(fd int32)
  
  var (
  	kq int32 = -1
  )
  
  func netpollinit() {
  	kq = kqueue()
  	if kq < 0 {
  		println("runtime: kqueue failed with", -kq)
  		throw("runtime: netpollinit failed")
  	}
  	closeonexec(kq)
  }
  
  func netpolldescriptor() uintptr {
  	return uintptr(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 -n
  	}
  	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("runtime: 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], int32(len(events)), tp)
  	if n < 0 {
  		if n != -_EINTR {
  			println("runtime: kevent on fd", kq, "failed with", -n)
  			throw("runtime: netpoll 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()
  }
  

View as plain text