Fix: Properly attach to running process on OSX

proc/proc.go

@@ -79,15 +79,6 @@ func (pe ProcessExitedError) Error() string {
 	return fmt.Sprintf("Process %d has exited with status %d", pe.Pid, pe.Status)
 }
 
-// Attach to an existing process with the given PID.
-func Attach(pid int) (*Process, error) {
-	dbp, err := initializeDebugProcess(New(pid), "", true)
-	if err != nil {
-		return nil, err
-	}
-	return dbp, nil
-}
-
 // Detach from the process being debugged, optionally killing it.
 func (dbp *Process) Detach(kill bool) (err error) {
 	if dbp.Running() {

proc/proc_darwin.go

@@ -82,6 +82,21 @@ func Launch(cmd []string) (*Process, error) {
 	return dbp, err
 }
 
+// Attach to an existing process with the given PID.
+func Attach(pid int) (*Process, error) {
+	dbp := New(pid)
+
+	kret := C.acquire_mach_task(C.int(pid),
+		&dbp.os.task, &dbp.os.portSet, &dbp.os.exceptionPort,
+		&dbp.os.notificationPort)
+
+	if kret != C.KERN_SUCCESS {
+		return nil, fmt.Errorf("could not attach to %d", pid)
+	}
+
+	return initializeDebugProcess(dbp, "", true)
+}
+
 func (dbp *Process) Kill() (err error) {
 	err = sys.Kill(dbp.Pid, sys.SIGKILL)
 	if err != nil {

proc/proc_linux.go

@@ -57,6 +57,11 @@ func Launch(cmd []string) (*Process, error) {
 	return initializeDebugProcess(dbp, proc.Path, false)
 }
 
+// Attach to an existing process with the given PID.
+func Attach(pid int) (*Process, error) {
+	return initializeDebugProcess(New(pid), "", true)
+}
+
 func (dbp *Process) Kill() (err error) {
 	if !stopped(dbp.Pid) {
 		return errors.New("process must be stopped in order to kill it")