net: use WSASocket instead of socket call

WSASocket (unlike socket call) allows to create sockets that
will not be inherited by child process. So call WSASocket to
save on using syscall.ForkLock and calling syscall.CloseOnExec.

Some very old versions of Windows do not have that functionality.
Call socket, if WSASocket failed, to support these.

Change-Id: I2dab9fa00d1a8609dd6feae1c9cc31d4e55b8cb5
Reviewed-on: https://go-review.googlesource.com/72590
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/go/build/deps_test.go

@@ -266,7 +266,7 @@ var pkgDeps = map[string][]string{
 	"math/big":                 {"L4"},
 	"mime":                     {"L4", "OS", "syscall", "internal/syscall/windows/registry"},
 	"mime/quotedprintable":     {"L4"},
-	"net/internal/socktest":    {"L4", "OS", "syscall"},
+	"net/internal/socktest":    {"L4", "OS", "syscall", "internal/syscall/windows"},
 	"net/url":                  {"L4"},
 	"plugin":                   {"L0", "OS", "CGO"},
 	"runtime/pprof/internal/profile": {"L4", "OS", "compress/gzip", "regexp"},

src/internal/syscall/windows/syscall_windows.go

@@ -112,6 +112,13 @@ const (
 //sys	MoveFileEx(from *uint16, to *uint16, flags uint32) (err error) = MoveFileExW
 //sys	GetModuleFileName(module syscall.Handle, fn *uint16, len uint32) (n uint32, err error) = kernel32.GetModuleFileNameW
 
+const (
+	WSA_FLAG_OVERLAPPED        = 0x01
+	WSA_FLAG_NO_HANDLE_INHERIT = 0x80
+)
+
+//sys	WSASocket(af int32, typ int32, protocol int32, protinfo *syscall.WSAProtocolInfo, group uint32, flags uint32) (handle syscall.Handle, err error) [failretval==syscall.InvalidHandle] = ws2_32.WSASocketW
+
 const (
 	ComputerNameNetBIOS                   = 0
 	ComputerNameDnsHostname               = 1

src/internal/syscall/windows/zsyscall_windows.go

@@ -38,6 +38,7 @@ func errnoErr(e syscall.Errno) error {
 var (
 	modiphlpapi = syscall.NewLazyDLL(sysdll.Add("iphlpapi.dll"))
 	modkernel32 = syscall.NewLazyDLL(sysdll.Add("kernel32.dll"))
+	modws2_32   = syscall.NewLazyDLL(sysdll.Add("ws2_32.dll"))
 	modnetapi32 = syscall.NewLazyDLL(sysdll.Add("netapi32.dll"))
 	modadvapi32 = syscall.NewLazyDLL(sysdll.Add("advapi32.dll"))
 	modpsapi    = syscall.NewLazyDLL(sysdll.Add("psapi.dll"))
@@ -46,6 +47,7 @@ var (
 	procGetComputerNameExW        = modkernel32.NewProc("GetComputerNameExW")
 	procMoveFileExW               = modkernel32.NewProc("MoveFileExW")
 	procGetModuleFileNameW        = modkernel32.NewProc("GetModuleFileNameW")
+	procWSASocketW                = modws2_32.NewProc("WSASocketW")
 	procGetACP                    = modkernel32.NewProc("GetACP")
 	procGetConsoleCP              = modkernel32.NewProc("GetConsoleCP")
 	procMultiByteToWideChar       = modkernel32.NewProc("MultiByteToWideChar")
@@ -108,6 +110,19 @@ func GetModuleFileName(module syscall.Handle, fn *uint16, len uint32) (n uint32,
 	return
 }
 
+func WSASocket(af int32, typ int32, protocol int32, protinfo *syscall.WSAProtocolInfo, group uint32, flags uint32) (handle syscall.Handle, err error) {
+	r0, _, e1 := syscall.Syscall6(procWSASocketW.Addr(), 6, uintptr(af), uintptr(typ), uintptr(protocol), uintptr(unsafe.Pointer(protinfo)), uintptr(group), uintptr(flags))
+	handle = syscall.Handle(r0)
+	if handle == syscall.InvalidHandle {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
 func GetACP() (acp uint32) {
 	r0, _, _ := syscall.Syscall(procGetACP.Addr(), 0, 0, 0, 0)
 	acp = uint32(r0)

src/net/hook_windows.go

@@ -5,6 +5,7 @@
 package net
 
 import (
+	"internal/syscall/windows"
 	"syscall"
 	"time"
 )
@@ -13,7 +14,8 @@ var (
 	testHookDialChannel = func() { time.Sleep(time.Millisecond) } // see golang.org/issue/5349
 
 	// Placeholders for socket system calls.
-	socketFunc  func(int, int, int) (syscall.Handle, error)  = syscall.Socket
-	connectFunc func(syscall.Handle, syscall.Sockaddr) error = syscall.Connect
-	listenFunc  func(syscall.Handle, int) error              = syscall.Listen
+	socketFunc    func(int, int, int) (syscall.Handle, error)                                                 = syscall.Socket
+	wsaSocketFunc func(int32, int32, int32, *syscall.WSAProtocolInfo, uint32, uint32) (syscall.Handle, error) = windows.WSASocket
+	connectFunc   func(syscall.Handle, syscall.Sockaddr) error                                                = syscall.Connect
+	listenFunc    func(syscall.Handle, int) error                                                             = syscall.Listen
 )

src/net/internal/socktest/sys_windows.go

@@ -4,7 +4,10 @@
 
 package socktest
 
-import "syscall"
+import (
+	"internal/syscall/windows"
+	"syscall"
+)
 
 // Socket wraps syscall.Socket.
 func (sw *Switch) Socket(family, sotype, proto int) (s syscall.Handle, err error) {
@@ -38,6 +41,38 @@ func (sw *Switch) Socket(family, sotype, proto int) (s syscall.Handle, err error
 	return s, nil
 }
 
+// WSASocket wraps syscall.WSASocket.
+func (sw *Switch) WSASocket(family, sotype, proto int32, protinfo *syscall.WSAProtocolInfo, group uint32, flags uint32) (s syscall.Handle, err error) {
+	sw.once.Do(sw.init)
+
+	so := &Status{Cookie: cookie(int(family), int(sotype), int(proto))}
+	sw.fmu.RLock()
+	f, _ := sw.fltab[FilterSocket]
+	sw.fmu.RUnlock()
+
+	af, err := f.apply(so)
+	if err != nil {
+		return syscall.InvalidHandle, err
+	}
+	s, so.Err = windows.WSASocket(family, sotype, proto, protinfo, group, flags)
+	if err = af.apply(so); err != nil {
+		if so.Err == nil {
+			syscall.Closesocket(s)
+		}
+		return syscall.InvalidHandle, err
+	}
+
+	sw.smu.Lock()
+	defer sw.smu.Unlock()
+	if so.Err != nil {
+		sw.stats.getLocked(so.Cookie).OpenFailed++
+		return syscall.InvalidHandle, so.Err
+	}
+	nso := sw.addLocked(s, int(family), int(sotype), int(proto))
+	sw.stats.getLocked(nso.Cookie).Opened++
+	return s, nil
+}
+
 // Closesocket wraps syscall.Closesocket.
 func (sw *Switch) Closesocket(s syscall.Handle) (err error) {
 	so := sw.sockso(s)

src/net/main_windows_test.go

@@ -9,6 +9,7 @@ import "internal/poll"
 var (
 	// Placeholders for saving original socket system calls.
 	origSocket      = socketFunc
+	origWSASocket   = wsaSocketFunc
 	origClosesocket = poll.CloseFunc
 	origConnect     = connectFunc
 	origConnectEx   = poll.ConnectExFunc
@@ -18,6 +19,7 @@ var (
 
 func installTestHooks() {
 	socketFunc = sw.Socket
+	wsaSocketFunc = sw.WSASocket
 	poll.CloseFunc = sw.Closesocket
 	connectFunc = sw.Connect
 	poll.ConnectExFunc = sw.ConnectEx
@@ -27,6 +29,7 @@ func installTestHooks() {
 
 func uninstallTestHooks() {
 	socketFunc = origSocket
+	wsaSocketFunc = origWSASocket
 	poll.CloseFunc = origClosesocket
 	connectFunc = origConnect
 	poll.ConnectExFunc = origConnectEx

src/net/sock_windows.go

@@ -5,6 +5,7 @@
 package net
 
 import (
+	"internal/syscall/windows"
 	"os"
 	"syscall"
 )
@@ -16,9 +17,19 @@ func maxListenerBacklog() int {
 }
 
 func sysSocket(family, sotype, proto int) (syscall.Handle, error) {
+	s, err := wsaSocketFunc(int32(family), int32(sotype), int32(proto),
+		nil, 0, windows.WSA_FLAG_OVERLAPPED|windows.WSA_FLAG_NO_HANDLE_INHERIT)
+	if err == nil {
+		return s, nil
+	}
+	// WSA_FLAG_NO_HANDLE_INHERIT flag is not supported on some
+	// old versions of Windows, see
+	// https://msdn.microsoft.com/en-us/library/windows/desktop/ms742212(v=vs.85).aspx
+	// for details. Just use syscall.Socket, if windows.WSASocket failed.
+
 	// See ../syscall/exec_unix.go for description of ForkLock.
 	syscall.ForkLock.RLock()
-	s, err := socketFunc(family, sotype, proto)
+	s, err = socketFunc(family, sotype, proto)
 	if err == nil {
 		syscall.CloseOnExec(s)
 	}