Add OpenAt Opcode

src/schemev2.rs

@@ -129,6 +129,8 @@ pub enum Opcode {
     Getdents = 26,
     CloseMsg = 27,
     Call = 28,
+
+    OpenAt = 29,  // fd, buf_ptr, buf_len, flags
 }
 
 impl Opcode {
@@ -169,6 +171,8 @@ impl Opcode {
             27 => CloseMsg,
             28 => Call,
 
+            29 => OpenAt,
+
             _ => return None,
         })
     }