runtime: do not exit(2) if a Go built DLL receives a signal

Fixes #35965

Change-Id: I172501fc0b29595e59b058f6e30f31efe5f6d1f9
Reviewed-on: https://go-review.googlesource.com/c/go/+/211139
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

1 files changed, 87 insertions, 0 deletions

diff --git a/src/runtime/signal_windows_test.go b/src/runtime/signal_windows_test.go
index 9748403412..423516df65 100644
--- a/src/runtime/signal_windows_test.go
+++ b/src/runtime/signal_windows_test.go
@@ -3,6 +3,8 @@
 package runtime_test
 
 import (
+	"bufio"
+	"bytes"
 	"internal/testenv"
 	"io/ioutil"
 	"os"
@@ -10,6 +12,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"strings"
+	"syscall"
 	"testing"
 )
 
@@ -59,3 +62,87 @@ func TestVectoredHandlerDontCrashOnLibrary(t *testing.T) {
 		t.Errorf("expected output %q, got %q", expectedOutput, cleanedOut)
 	}
 }
+
+func sendCtrlBreak(t *testing.T, pid int) {
+	kernel32, err := syscall.LoadDLL("kernel32.dll")
+	if err != nil {
+		t.Fatalf("LoadDLL: %v\n", err)
+	}
+	generateEvent, err := kernel32.FindProc("GenerateConsoleCtrlEvent")
+	if err != nil {
+		t.Fatalf("FindProc: %v\n", err)
+	}
+	result, _, err := generateEvent.Call(syscall.CTRL_BREAK_EVENT, uintptr(pid))
+	if result == 0 {
+		t.Fatalf("GenerateConsoleCtrlEvent: %v\n", err)
+	}
+}
+
+// TestLibraryCtrlHandler tests that Go DLL allows calling program to handle console control events.
+// See https://golang.org/issues/35965.
+func TestLibraryCtrlHandler(t *testing.T) {
+	if *flagQuick {
+		t.Skip("-quick")
+	}
+	if runtime.GOARCH != "amd64" {
+		t.Skip("this test can only run on windows/amd64")
+	}
+	testenv.MustHaveGoBuild(t)
+	testenv.MustHaveExecPath(t, "gcc")
+	testprog.Lock()
+	defer testprog.Unlock()
+	dir, err := ioutil.TempDir("", "go-build")
+	if err != nil {
+		t.Fatalf("failed to create temp directory: %v", err)
+	}
+	defer os.RemoveAll(dir)
+
+	// build go dll
+	dll := filepath.Join(dir, "dummy.dll")
+	cmd := exec.Command(testenv.GoToolPath(t), "build", "-o", dll, "--buildmode", "c-shared", "testdata/testwinlibsignal/dummy.go")
+	out, err := testenv.CleanCmdEnv(cmd).CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to build go library: %s\n%s", err, out)
+	}
+
+	// build c program
+	exe := filepath.Join(dir, "test.exe")
+	cmd = exec.Command("gcc", "-o", exe, "testdata/testwinlibsignal/main.c")
+	out, err = testenv.CleanCmdEnv(cmd).CombinedOutput()
+	if err != nil {
+		t.Fatalf("failed to build c exe: %s\n%s", err, out)
+	}
+
+	// run test program
+	cmd = exec.Command(exe)
+	var stderr bytes.Buffer
+	cmd.Stderr = &stderr
+	outPipe, err := cmd.StdoutPipe()
+	if err != nil {
+		t.Fatalf("Failed to create stdout pipe: %v", err)
+	}
+	outReader := bufio.NewReader(outPipe)
+
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		CreationFlags: syscall.CREATE_NEW_PROCESS_GROUP,
+	}
+	if err := cmd.Start(); err != nil {
+		t.Fatalf("Start failed: %v", err)
+	}
+
+	sentCtrl := make(chan bool)
+	go func() {
+		defer close(sentCtrl)
+		if line, err := outReader.ReadString('\n'); err != nil {
+			t.Fatalf("Could not read stdout: %v", err)
+		} else if strings.TrimSpace(line) != "ready" {
+			t.Fatalf("Unexpected message: %v", line)
+		}
+		sendCtrlBreak(t, cmd.Process.Pid)
+	}()
+
+	<-sentCtrl
+	if err := cmd.Wait(); err != nil {
+		t.Fatalf("Program exited with error: %v\n%s", err, &stderr)
+	}
+}