1 files changed, 136 insertions, 0 deletions
diff --git a/misc/cgo/test/callback.go b/misc/cgo/test/callback.go
new file mode 100644
index 000000000..450a7cbf2
--- /dev/null
+++ b/misc/cgo/test/callback.go
@@ -0,0 +1,136 @@
+package cgotest
+
+/*
+void callback(void *f);
+void callGoFoo(void) {
+	extern void goFoo(void);
+	goFoo();
+}
+*/
+import "C"
+
+import (
+	"runtime"
+	"testing"
+	"unsafe"
+)
+
+// nestedCall calls into C, back into Go, and finally to f.
+func nestedCall(f func()) {
+	// NOTE: Depends on representation of f.
+	// callback(x) calls goCallback(x)
+	C.callback(*(*unsafe.Pointer)(unsafe.Pointer(&f)))
+}
+
+//export goCallback
+func goCallback(p unsafe.Pointer) {
+	(*(*func())(unsafe.Pointer(&p)))()
+}
+
+func TestCallback(t *testing.T) {
+	var x = false
+	nestedCall(func() { x = true })
+	if !x {
+		t.Fatal("nestedCall did not call func")
+	}
+}
+
+func TestCallbackGC(t *testing.T) {
+	nestedCall(runtime.GC)
+}
+
+func lockedOSThread() bool // in runtime.c
+
+func TestCallbackPanic(t *testing.T) {
+	// Make sure panic during callback unwinds properly.
+	if lockedOSThread() {
+		t.Fatal("locked OS thread on entry to TestCallbackPanic")
+	}
+	defer func() {
+		s := recover()
+		if s == nil {
+			t.Fatal("did not panic")
+		}
+		if s.(string) != "callback panic" {
+			t.Fatal("wrong panic:", s)
+		}
+		if lockedOSThread() {
+			t.Fatal("locked OS thread on exit from TestCallbackPanic")
+		}
+	}()
+	nestedCall(func() { panic("callback panic") })
+	panic("nestedCall returned")
+}
+
+func TestCallbackPanicLoop(t *testing.T) {
+	// Make sure we don't blow out m->g0 stack.
+	for i := 0; i < 100000; i++ {
+		TestCallbackPanic(t)
+	}
+}
+
+func TestCallbackPanicLocked(t *testing.T) {
+	runtime.LockOSThread()
+	defer runtime.UnlockOSThread()
+
+	if !lockedOSThread() {
+		t.Fatal("runtime.LockOSThread didn't")
+	}
+	defer func() {
+		s := recover()
+		if s == nil {
+			t.Fatal("did not panic")
+		}
+		if s.(string) != "callback panic" {
+			t.Fatal("wrong panic:", s)
+		}
+		if !lockedOSThread() {
+			t.Fatal("lost lock on OS thread after panic")
+		}
+	}()
+	nestedCall(func() { panic("callback panic") })
+	panic("nestedCall returned")
+}
+
+// Callback with zero arguments used to make the stack misaligned,
+// which broke the garbage collector and other things.
+func TestZeroArgCallback(t *testing.T) {
+	defer func() {
+		s := recover()
+		if s != nil {
+			t.Fatal("panic during callback:", s)
+		}
+	}()
+	C.callGoFoo()
+}
+
+//export goFoo
+func goFoo() {
+	x := 1
+	for i := 0; i < 10000; i++ {
+		// variadic call mallocs + writes to 
+		variadic(x, x, x)
+		if x != 1 {
+			panic("bad x")
+		}
+	}
+}
+
+func variadic(x ...interface{}) {}
+
+func TestBlocking(t *testing.T) {
+	c := make(chan int)
+	go func() {
+		for i := 0; i < 10; i++ {
+			c <- <-c
+		}
+	}()
+	nestedCall(func() {
+		for i := 0; i < 10; i++ {
+			c <- i
+			if j := <-c; j != i {
+				t.Errorf("out of sync %d != %d", j, i)
+			}
+		}
+	})
+}