Go: add context api (#668)

bindings/go/unicorn/context.go

@@ -0,0 +1,28 @@
+package unicorn
+
+import (
+	"runtime"
+)
+
+// #include <unicorn/unicorn.h>
+import "C"
+
+type Context **C.uc_context
+
+func (u *uc) ContextSave(reuse Context) (Context, error) {
+	ctx := reuse
+	if ctx == nil {
+		ctx = new(*C.uc_context)
+	}
+	if err := errReturn(C.uc_context_alloc(u.handle, ctx)); err != nil {
+		return nil, err
+	}
+	runtime.SetFinalizer(ctx, func(p Context) { C.uc_context_free(*p) })
+	if err := errReturn(C.uc_context_save(u.handle, *ctx)); err != nil {
+	}
+	return ctx, nil
+}
+
+func (u *uc) ContextRestore(ctx Context) error {
+	return errReturn(C.uc_context_restore(u.handle, *ctx))
+}

bindings/go/unicorn/context_test.go

@@ -0,0 +1,26 @@
+package unicorn
+
+import (
+	"testing"
+)
+
+func TestContext(t *testing.T) {
+	u, err := NewUnicorn(ARCH_X86, MODE_32)
+	if err != nil {
+		t.Fatal(err)
+	}
+	u.RegWrite(X86_REG_EBP, 100)
+	ctx, err := u.ContextSave(nil)
+	if err != nil {
+		t.Fatal(err)
+	}
+	u.RegWrite(X86_REG_EBP, 200)
+	err = u.ContextRestore(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	val, _ := u.RegRead(X86_REG_EBP)
+	if val != 100 {
+		t.Fatal("context restore failed")
+	}
+}

bindings/go/unicorn/unicorn.go

@@ -55,6 +55,9 @@ type Unicorn interface {
 	HookDel(hook Hook) error
 	Query(queryType int) (uint64, error)
 	Close() error
+
+	ContextSave(reuse Context) (Context, error)
+	ContextRestore(Context) error
 }
 
 type uc struct {