Revert "os: add handling of os.Interrupt for windows"

This reverts CL 367495.

Reason for revert: broke `x/tools` tests on Windows.

Change-Id: Iab6b33259181c9520cf8db1e5b6edfeba763f974
Reviewed-on: https://go-review.googlesource.com/c/go/+/397997
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Bryan Mills <bcmills@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

4 files changed, 26 insertions, 34 deletions

diff --git a/src/os/exec/exec_windows_test.go b/src/os/exec/exec_windows_test.go
index 503867f9c8..8e31e47190 100644
--- a/src/os/exec/exec_windows_test.go
+++ b/src/os/exec/exec_windows_test.go
@@ -7,7 +7,6 @@
 package exec_test
 
 import (
-	"internal/testenv"
 	"io"
 	"os"
 	"os/exec"
@@ -55,20 +54,3 @@ func TestNoInheritHandles(t *testing.T) {
 		t.Fatalf("got exit code %d; want 88", exitError.ExitCode())
 	}
 }
-
-func TestErrProcessDone(t *testing.T) {
-	testenv.MustHaveGoBuild(t)
-	// On Windows, ProcAttr cannot be empty
-	p, err := os.StartProcess(testenv.GoToolPath(t), []string{""},
-		&os.ProcAttr{Dir: "", Env: nil, Files: []*os.File{os.Stdin, os.Stdout, os.Stderr}, Sys: nil})
-	if err != nil {
-		t.Errorf("starting test process: %v", err)
-	}
-	_, err = p.Wait()
-	if err != nil {
-		t.Errorf("Wait: %v", err)
-	}
-	if got := p.Signal(os.Kill); got != os.ErrProcessDone {
-		t.Fatalf("got %v want %v", got, os.ErrProcessDone)
-	}
-}
diff --git a/src/os/exec_posix.go b/src/os/exec_posix.go
index 3dc18a84bd..e1e7d53a27 100644
--- a/src/os/exec_posix.go
+++ b/src/os/exec_posix.go
@@ -15,7 +15,9 @@ import (
 
 // The only signal values guaranteed to be present in the os package on all
 // systems are os.Interrupt (send the process an interrupt) and os.Kill (force
-// the process to exit).
+// the process to exit). On Windows, sending os.Interrupt to a process with
+// os.Process.Signal is not implemented; it will return an error instead of
+// sending a signal.
 var (
 	Interrupt Signal = syscall.SIGINT
 	Kill      Signal = syscall.SIGKILL
diff --git a/src/os/exec_windows.go b/src/os/exec_windows.go
index bc232e0a00..239bed198f 100644
--- a/src/os/exec_windows.go
+++ b/src/os/exec_windows.go
@@ -47,14 +47,13 @@ func (p *Process) wait() (ps *ProcessState, err error) {
 
 func (p *Process) signal(sig Signal) error {
 	handle := atomic.LoadUintptr(&p.handle)
+	if handle == uintptr(syscall.InvalidHandle) {
+		return syscall.EINVAL
+	}
 	if p.done() {
 		return ErrProcessDone
 	}
-	s, ok := sig.(syscall.Signal)
-	if !ok {
-		return syscall.EWINDOWS
-	}
-	if s == syscall.SIGKILL {
+	if sig == Kill {
 		var terminationHandle syscall.Handle
 		e := syscall.DuplicateHandle(^syscall.Handle(0), syscall.Handle(handle), ^syscall.Handle(0), &terminationHandle, syscall.PROCESS_TERMINATE, false, 0)
 		if e != nil {
@@ -62,17 +61,11 @@ func (p *Process) signal(sig Signal) error {
 		}
 		runtime.KeepAlive(p)
 		defer syscall.CloseHandle(terminationHandle)
-		e = syscall.TerminateProcess(terminationHandle, 1)
+		e = syscall.TerminateProcess(syscall.Handle(terminationHandle), 1)
 		return NewSyscallError("TerminateProcess", e)
 	}
-	if s == syscall.SIGINT {
-		e := windows.GenerateConsoleCtrlEvent(syscall.CTRL_BREAK_EVENT, uint32(p.Pid))
-		if e != nil {
-			return NewSyscallError("GenerateConsoleCtrlEvent", e)
-		}
-		return nil
-	}
-	return syscall.EWINDOWS
+	// TODO(rsc): Handle Interrupt too?
+	return syscall.Errno(syscall.EWINDOWS)
 }
 
 func (p *Process) release() error {
diff --git a/src/os/signal/signal_windows_test.go b/src/os/signal/signal_windows_test.go
index 89c072ca6e..9b14551572 100644
--- a/src/os/signal/signal_windows_test.go
+++ b/src/os/signal/signal_windows_test.go
@@ -15,6 +15,21 @@ import (
 	"time"
 )
 
+func sendCtrlBreak(t *testing.T, pid int) {
+	d, e := syscall.LoadDLL("kernel32.dll")
+	if e != nil {
+		t.Fatalf("LoadDLL: %v\n", e)
+	}
+	p, e := d.FindProc("GenerateConsoleCtrlEvent")
+	if e != nil {
+		t.Fatalf("FindProc: %v\n", e)
+	}
+	r, _, e := p.Call(syscall.CTRL_BREAK_EVENT, uintptr(pid))
+	if r == 0 {
+		t.Fatalf("GenerateConsoleCtrlEvent: %v\n", e)
+	}
+}
+
 func TestCtrlBreak(t *testing.T) {
 	// create source file
 	const source = `
@@ -75,7 +90,7 @@ func main() {
 	}
 	go func() {
 		time.Sleep(1 * time.Second)
-		cmd.Process.Signal(os.Interrupt)
+		sendCtrlBreak(t, cmd.Process.Pid)
 	}()
 	err = cmd.Wait()
 	if err != nil {