windows: add support for CommTimeouts

CommTimeouts allows the user to set the timeout on Comm devices:

docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-setcommtimeouts
docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-getcommtimeouts

Change-Id: I756dc93b1b01412a496c6eccab22c9ff7e5f4b83
Reviewed-on: https://go-review.googlesource.com/c/sys/+/290209
Reviewed-by: Jason A. Donenfeld <Jason@zx2c4.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Trust: Jason A. Donenfeld <Jason@zx2c4.com>
Trust: Alex Brainman <alex.brainman@gmail.com>
Run-TryBot: Jason A. Donenfeld <Jason@zx2c4.com>
TryBot-Result: Go Bot <gobot@golang.org>

windows/syscall_windows.go

@@ -344,6 +344,8 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	SetProcessPriorityBoost(process Handle, disable bool) (err error) = kernel32.SetProcessPriorityBoost
 //sys	GetProcessWorkingSetSizeEx(hProcess Handle, lpMinimumWorkingSetSize *uintptr, lpMaximumWorkingSetSize *uintptr, flags *uint32)
 //sys	SetProcessWorkingSetSizeEx(hProcess Handle, dwMinimumWorkingSetSize uintptr, dwMaximumWorkingSetSize uintptr, flags uint32) (err error)
+//sys	GetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error)
+//sys	SetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error)
 
 // Volume Management Functions
 //sys	DefineDosDevice(flags uint32, deviceName *uint16, targetPath *uint16) (err error) = DefineDosDeviceW

windows/types_windows.go

@@ -2260,3 +2260,11 @@ const (
 	// REG_NOTIFY_THREAD_AGNOSTIC indicates that the lifetime of the registration must not be tied to the lifetime of the thread issuing the RegNotifyChangeKeyValue call. Note: This flag value is only supported in Windows 8 and later.
 	REG_NOTIFY_THREAD_AGNOSTIC = 0x10000000
 )
+
+type CommTimeouts struct {
+	ReadIntervalTimeout         uint32
+	ReadTotalTimeoutMultiplier  uint32
+	ReadTotalTimeoutConstant    uint32
+	WriteTotalTimeoutMultiplier uint32
+	WriteTotalTimeoutConstant   uint32
+}

windows/zsyscall_windows.go

@@ -212,6 +212,7 @@ var (
 	procFreeLibrary                                          = modkernel32.NewProc("FreeLibrary")
 	procGenerateConsoleCtrlEvent                             = modkernel32.NewProc("GenerateConsoleCtrlEvent")
 	procGetACP                                               = modkernel32.NewProc("GetACP")
+	procGetCommTimeouts                                      = modkernel32.NewProc("GetCommTimeouts")
 	procGetCommandLineW                                      = modkernel32.NewProc("GetCommandLineW")
 	procGetComputerNameExW                                   = modkernel32.NewProc("GetComputerNameExW")
 	procGetComputerNameW                                     = modkernel32.NewProc("GetComputerNameW")
@@ -296,6 +297,7 @@ var (
 	procRemoveDirectoryW                                     = modkernel32.NewProc("RemoveDirectoryW")
 	procResetEvent                                           = modkernel32.NewProc("ResetEvent")
 	procResumeThread                                         = modkernel32.NewProc("ResumeThread")
+	procSetCommTimeouts                                      = modkernel32.NewProc("SetCommTimeouts")
 	procSetConsoleCursorPosition                             = modkernel32.NewProc("SetConsoleCursorPosition")
 	procSetConsoleMode                                       = modkernel32.NewProc("SetConsoleMode")
 	procSetCurrentDirectoryW                                 = modkernel32.NewProc("SetCurrentDirectoryW")
@@ -1787,6 +1789,14 @@ func GetACP() (acp uint32) {
 	return
 }
 
+func GetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error) {
+	r1, _, e1 := syscall.Syscall(procGetCommTimeouts.Addr(), 2, uintptr(handle), uintptr(unsafe.Pointer(timeouts)), 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func GetCommandLine() (cmd *uint16) {
 	r0, _, _ := syscall.Syscall(procGetCommandLineW.Addr(), 0, 0, 0, 0)
 	cmd = (*uint16)(unsafe.Pointer(r0))
@@ -2537,6 +2547,14 @@ func ResumeThread(thread Handle) (ret uint32, err error) {
 	return
 }
 
+func SetCommTimeouts(handle Handle, timeouts *CommTimeouts) (err error) {
+	r1, _, e1 := syscall.Syscall(procSetCommTimeouts.Addr(), 2, uintptr(handle), uintptr(unsafe.Pointer(timeouts)), 0)
+	if r1 == 0 {
+		err = errnoErr(e1)
+	}
+	return
+}
+
 func setConsoleCursorPosition(console Handle, position uint32) (err error) {
 	r1, _, e1 := syscall.Syscall(procSetConsoleCursorPosition.Addr(), 2, uintptr(console), uintptr(position), 0)
 	if r1 == 0 {