1 files changed, 97 insertions, 0 deletions
diff --git a/src/runtime/netpoll_epoll.go b/src/runtime/netpoll_epoll.go
new file mode 100644
index 000000000..ecfc9cdde
--- /dev/null
+++ b/src/runtime/netpoll_epoll.go
@@ -0,0 +1,97 @@
+// 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
+}