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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 linux
package runtime
import "unsafe"
func epollcreate(size int32) int32
func epollcreate1(flags int32) int32
//go:noescape
func epollctl(epfd, op, fd int32, ev *epollevent) int32
//go:noescape
func epollwait(epfd int32, ev *epollevent, nev, timeout int32) int32
func closeonexec(fd int32)
var (
epfd int32 = -1 // epoll descriptor
netpolllasterr int32
)
func netpollinit() {
epfd = epollcreate1(_EPOLL_CLOEXEC)
if epfd >= 0 {
return
}
epfd = epollcreate(1024)
if epfd >= 0 {
closeonexec(epfd)
return
}
println("netpollinit: failed to create epoll descriptor", -epfd)
gothrow("netpollinit: failed to create descriptor")
}
func netpollopen(fd uintptr, pd *pollDesc) int32 {
var ev epollevent
ev.events = _EPOLLIN | _EPOLLOUT | _EPOLLRDHUP | _EPOLLET
*(**pollDesc)(unsafe.Pointer(&ev.data)) = pd
return -epollctl(epfd, _EPOLL_CTL_ADD, int32(fd), &ev)
}
func netpollclose(fd uintptr) int32 {
var ev epollevent
return -epollctl(epfd, _EPOLL_CTL_DEL, int32(fd), &ev)
}
func netpollarm(pd *pollDesc, mode int) {
gothrow("unused")
}
// polls for ready network connections
// returns list of goroutines that become runnable
func netpoll(block bool) (gp *g) {
if epfd == -1 {
return
}
waitms := int32(-1)
if !block {
waitms = 0
}
var events [128]epollevent
retry:
n := epollwait(epfd, &events[0], int32(len(events)), waitms)
if n < 0 {
if n != -_EINTR && n != netpolllasterr {
netpolllasterr = n
println("runtime: epollwait on fd", epfd, "failed with", -n)
}
goto retry
}
for i := int32(0); i < n; i++ {
ev := &events[i]
if ev.events == 0 {
continue
}
var mode int32
if ev.events&(_EPOLLIN|_EPOLLRDHUP|_EPOLLHUP|_EPOLLERR) != 0 {
mode += 'r'
}
if ev.events&(_EPOLLOUT|_EPOLLHUP|_EPOLLERR) != 0 {
mode += 'w'
}
if mode != 0 {
pd := *(**pollDesc)(unsafe.Pointer(&ev.data))
netpollready((**g)(noescape(unsafe.Pointer(&gp))), pd, mode)
}
}
if block && gp == nil {
goto retry
}
return gp
}
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