Handle set_pc errors

proctl/registers_darwin_amd64.go

@@ -17,7 +17,10 @@ func (r *Regs) SP() uint64 {
 }
 
 func (r *Regs) SetPC(thread *ThreadContext, pc uint64) error {
-	C.set_pc(thread.os.thread_act, C.uint64_t(pc))
+	kret := C.set_pc(thread.os.thread_act, C.uint64_t(pc))
+	if kret != C.KERN_SUCCESS {
+		return fmt.Errorf("could not set pc")
+	}
 	return nil
 }
 

proctl/threads_darwin.c

@@ -47,19 +47,18 @@ get_registers(mach_port_name_t task, x86_thread_state64_t *state) {
 }
 
 // TODO(dp) this should return kret instead of void
-void
+kern_return_t
 set_pc(thread_act_t task, uint64_t pc) {
 	kern_return_t kret;
 	x86_thread_state64_t state;
 	mach_msg_type_number_t stateCount = x86_THREAD_STATE64_COUNT;
 
 	kret = thread_get_state(task, x86_THREAD_STATE64, (thread_state_t)&state, &stateCount);
-	if (kret != KERN_SUCCESS) puts(mach_error_string(kret));
+	if (kret != KERN_SUCCESS) return kret;
 	state.__rip = pc;
 
-	kret = thread_set_state(task, x86_THREAD_STATE64, (thread_state_t)&state, stateCount);
-	if (kret != KERN_SUCCESS) puts(mach_error_string(kret));
 	// TODO(dp) - possible memory leak - vm_deallocate state
+	return thread_set_state(task, x86_THREAD_STATE64, (thread_state_t)&state, stateCount);
 }
 
 // TODO(dp) this should return kret instead of void

proctl/threads_darwin.h

@@ -13,7 +13,7 @@ read_memory(mach_port_name_t, mach_vm_address_t, void *, mach_msg_type_number_t)
 kern_return_t
 get_registers(mach_port_name_t, x86_thread_state64_t*);
 
-void
+kern_return_t
 set_pc(thread_act_t, uint64_t);
 
 void