[dev.cc] runtime: convert netpoll_windows.c to Go

LGTM=rsc
R=rsc
CC=dvyukov, golang-codereviews
https://golang.org/cl/172530043

src/runtime/netpoll_windows.c

-// 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.
-
-#include "runtime.h"
-#include "defs_GOOS_GOARCH.h"
-#include "os_GOOS.h"
-
-#define DWORD_MAX 0xffffffff
-
-#pragma dynimport runtime·CreateIoCompletionPort CreateIoCompletionPort "kernel32.dll"
-#pragma dynimport runtime·GetQueuedCompletionStatus GetQueuedCompletionStatus "kernel32.dll"
-#pragma dynimport runtime·WSAGetOverlappedResult WSAGetOverlappedResult "ws2_32.dll"
-
-extern void *runtime·CreateIoCompletionPort;
-extern void *runtime·GetQueuedCompletionStatus;
-extern void *runtime·WSAGetOverlappedResult;
-
-#define INVALID_HANDLE_VALUE ((uintptr)-1)
-
-// net_op must be the same as beginning of net.operation. Keep these in sync.
-typedef struct net_op net_op;
-struct net_op
-{
-	// used by windows
-	Overlapped	o;
-	// used by netpoll
-	PollDesc*	pd;
-	int32	mode;
-	int32	errno;
-	uint32	qty;
-};
-
-typedef struct OverlappedEntry OverlappedEntry;
-struct OverlappedEntry
-{
-	uintptr	key;
-	net_op*	op;  // In reality it's Overlapped*, but we cast it to net_op* anyway.
-	uintptr	internal;
-	uint32	qty;
-};
-
-static void handlecompletion(G **gpp, net_op *o, int32 errno, uint32 qty);
-
-static uintptr iocphandle = INVALID_HANDLE_VALUE;  // completion port io handle
-
-void
-runtime·netpollinit(void)
-{
-	iocphandle = (uintptr)runtime·stdcall4(runtime·CreateIoCompletionPort, INVALID_HANDLE_VALUE, 0, 0, DWORD_MAX);
-	if(iocphandle == 0) {
-		runtime·printf("netpoll: failed to create iocp handle (errno=%d)\n", runtime·getlasterror());
-		runtime·throw("netpoll: failed to create iocp handle");
-	}
-	return;
-}
-
-int32
-runtime·netpollopen(uintptr fd, PollDesc *pd)
-{
-	USED(pd);
-	if(runtime·stdcall4(runtime·CreateIoCompletionPort, fd, iocphandle, 0, 0) == 0)
-		return -runtime·getlasterror();
-	return 0;
-}
-
-int32
-runtime·netpollclose(uintptr fd)
-{
-	// nothing to do
-	USED(fd);
-	return 0;
-}
-
-void
-runtime·netpollarm(PollDesc* pd, int32 mode)
-{
-	USED(pd, mode);
-	runtime·throw("unused");
-}
-
-// Polls for completed network IO.
-// Returns list of goroutines that become runnable.
-G*
-runtime·netpoll(bool block)
-{
-	OverlappedEntry entries[64];
-	uint32 wait, qty, key, flags, n, i;
-	int32 errno;
-	net_op *op;
-	G *gp;
-
-	if(iocphandle == INVALID_HANDLE_VALUE)
-		return nil;
-	gp = nil;
-	wait = 0;
-	if(block)
-		wait = INFINITE;
-retry:
-	if(runtime·GetQueuedCompletionStatusEx != nil) {
-		n = nelem(entries) / runtime·gomaxprocs;
-		if(n < 8)
-			n = 8;
-		if(block)
-			g->m->blocked = true;
-		if(runtime·stdcall6(runtime·GetQueuedCompletionStatusEx, iocphandle, (uintptr)entries, n, (uintptr)&n, wait, 0) == 0) {
-			g->m->blocked = false;
-			errno = runtime·getlasterror();
-			if(!block && errno == WAIT_TIMEOUT)
-				return nil;
-			runtime·printf("netpoll: GetQueuedCompletionStatusEx failed (errno=%d)\n", errno);
-			runtime·throw("netpoll: GetQueuedCompletionStatusEx failed");
-		}
-		g->m->blocked = false;
-		for(i = 0; i < n; i++) {
-			op = entries[i].op;
-			errno = 0;
-			qty = 0;
-			if(runtime·stdcall5(runtime·WSAGetOverlappedResult, runtime·netpollfd(op->pd), (uintptr)op, (uintptr)&qty, 0, (uintptr)&flags) == 0)
-				errno = runtime·getlasterror();
-			handlecompletion(&gp, op, errno, qty);
-		}
-	} else {
-		op = nil;
-		errno = 0;
-		qty = 0;
-		if(block)
-			g->m->blocked = true;
-		if(runtime·stdcall5(runtime·GetQueuedCompletionStatus, iocphandle, (uintptr)&qty, (uintptr)&key, (uintptr)&op, wait) == 0) {
-			g->m->blocked = false;
-			errno = runtime·getlasterror();
-			if(!block && errno == WAIT_TIMEOUT)
-				return nil;
-			if(op == nil) {
-				runtime·printf("netpoll: GetQueuedCompletionStatus failed (errno=%d)\n", errno);
-				runtime·throw("netpoll: GetQueuedCompletionStatus failed");
-			}
-			// dequeued failed IO packet, so report that
-		}
-		g->m->blocked = false;
-		handlecompletion(&gp, op, errno, qty);
-	}
-	if(block && gp == nil)
-		goto retry;
-	return gp;
-}
-
-static void
-handlecompletion(G **gpp, net_op *op, int32 errno, uint32 qty)
-{
-	int32 mode;
-
-	if(op == nil)
-		runtime·throw("netpoll: GetQueuedCompletionStatus returned op == nil");
-	mode = op->mode;
-	if(mode != 'r' && mode != 'w') {
-		runtime·printf("netpoll: GetQueuedCompletionStatus returned invalid mode=%d\n", mode);
-		runtime·throw("netpoll: GetQueuedCompletionStatus returned invalid mode");
-	}
-	op->errno = errno;
-	op->qty = qty;
-	runtime·netpollready(gpp, op->pd, mode);
-}

src/runtime/netpoll_windows.go

+// 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.
+
+package runtime
+
+import (
+	"unsafe"
+)
+
+const _DWORD_MAX = 0xffffffff
+
+//go:cgo_import_dynamic runtime._CreateIoCompletionPort CreateIoCompletionPort "kernel32.dll"
+//go:cgo_import_dynamic runtime._GetQueuedCompletionStatus GetQueuedCompletionStatus "kernel32.dll"
+//go:cgo_import_dynamic runtime._WSAGetOverlappedResult WSAGetOverlappedResult "ws2_32.dll"
+
+var (
+	_CreateIoCompletionPort,
+	_GetQueuedCompletionStatus,
+	_WSAGetOverlappedResult stdFunction
+)
+
+const _INVALID_HANDLE_VALUE = ^uintptr(0)
+
+// net_op must be the same as beginning of net.operation. Keep these in sync.
+type net_op struct {
+	// used by windows
+	o overlapped
+	// used by netpoll
+	pd    *pollDesc
+	mode  int32
+	errno int32
+	qty   uint32
+}
+
+type overlappedEntry struct {
+	key      uintptr
+	op       *net_op // In reality it's *overlapped, but we cast it to *net_op anyway.
+	internal uintptr
+	qty      uint32
+}
+
+var iocphandle uintptr = _INVALID_HANDLE_VALUE // completion port io handle
+
+func netpollinit() {
+	iocphandle = uintptr(stdcall4(_CreateIoCompletionPort, _INVALID_HANDLE_VALUE, 0, 0, _DWORD_MAX))
+	if iocphandle == 0 {
+		println("netpoll: failed to create iocp handle (errno=", getlasterror(), ")")
+		gothrow("netpoll: failed to create iocp handle")
+	}
+}
+
+func netpollopen(fd uintptr, pd *pollDesc) int32 {
+	if stdcall4(_CreateIoCompletionPort, fd, iocphandle, 0, 0) == 0 {
+		return -int32(getlasterror())
+	}
+	return 0
+}
+
+func netpollclose(fd uintptr) int32 {
+	// nothing to do
+	return 0
+}
+
+func netpollarm(pd *pollDesc, mode int) {
+	gothrow("unused")
+}
+
+// Polls for completed network IO.
+// Returns list of goroutines that become runnable.
+func netpoll(block bool) *g {
+	var entries [64]overlappedEntry
+	var wait, qty, key, flags, n, i uint32
+	var errno int32
+	var op *net_op
+	var gp *g
+
+	mp := getg().m
+
+	if iocphandle == _INVALID_HANDLE_VALUE {
+		return nil
+	}
+	gp = nil
+	wait = 0
+	if block {
+		wait = _INFINITE
+	}
+retry:
+	if _GetQueuedCompletionStatusEx != nil {
+		n = uint32(len(entries) / int(gomaxprocs))
+		if n < 8 {
+			n = 8
+		}
+		if block {
+			mp.blocked = true
+		}
+		if stdcall6(_GetQueuedCompletionStatusEx, iocphandle, uintptr(unsafe.Pointer(&entries[0])), uintptr(n), uintptr(unsafe.Pointer(&n)), uintptr(wait), 0) == 0 {
+			mp.blocked = false
+			errno = int32(getlasterror())
+			if !block && errno == _WAIT_TIMEOUT {
+				return nil
+			}
+			println("netpoll: GetQueuedCompletionStatusEx failed (errno=", errno, ")")
+			gothrow("netpoll: GetQueuedCompletionStatusEx failed")
+		}
+		mp.blocked = false
+		for i = 0; i < n; i++ {
+			op = entries[i].op
+			errno = 0
+			qty = 0
+			if stdcall5(_WSAGetOverlappedResult, netpollfd(op.pd), uintptr(unsafe.Pointer(op)), uintptr(unsafe.Pointer(&qty)), 0, uintptr(unsafe.Pointer(&flags))) == 0 {
+				errno = int32(getlasterror())
+			}
+			handlecompletion(&gp, op, errno, qty)
+		}
+	} else {
+		op = nil
+		errno = 0
+		qty = 0
+		if block {
+			mp.blocked = true
+		}
+		if stdcall5(_GetQueuedCompletionStatus, iocphandle, uintptr(unsafe.Pointer(&qty)), uintptr(unsafe.Pointer(&key)), uintptr(unsafe.Pointer(&op)), uintptr(wait)) == 0 {
+			mp.blocked = false
+			errno = int32(getlasterror())
+			if !block && errno == _WAIT_TIMEOUT {
+				return nil
+			}
+			if op == nil {
+				println("netpoll: GetQueuedCompletionStatus failed (errno=", errno, ")")
+				gothrow("netpoll: GetQueuedCompletionStatus failed")
+			}
+			// dequeued failed IO packet, so report that
+		}
+		mp.blocked = false
+		handlecompletion(&gp, op, errno, qty)
+	}
+	if block && gp == nil {
+		goto retry
+	}
+	return gp
+}
+
+func handlecompletion(gpp **g, op *net_op, errno int32, qty uint32) {
+	if op == nil {
+		gothrow("netpoll: GetQueuedCompletionStatus returned op == nil")
+	}
+	mode := op.mode
+	if mode != 'r' && mode != 'w' {
+		println("netpoll: GetQueuedCompletionStatus returned invalid mode=", mode)
+		gothrow("netpoll: GetQueuedCompletionStatus returned invalid mode")
+	}
+	op.errno = errno
+	op.qty = qty
+	netpollready(gpp, op.pd, mode)
+}

src/runtime/os_windows.go

@@ -21,10 +21,6 @@ func asmstdcall(fn unsafe.Pointer)
 func getlasterror() uint32
 func setlasterror(err uint32)
 func usleep1(usec uint32)
-func netpollinit()
-func netpollopen(fd uintptr, pd *pollDesc) int32
-func netpollclose(fd uintptr) int32
-func netpollarm(pd *pollDesc, mode int)
 
 func os_sigpipe() {
 	gothrow("too many writes on closed pipe")