[kernel] Pass objects not handles to syscall impls

This commit contains a couple large, interdependent changes:

- In preparation for capability checking, the _syscall_verify_*
  functions now load most handles passed in, and verify that they exist
  and are of the correct type. Lists and out-handles are not converted
  to objects.
- Also in preparation for capability checking, the internal
  representation of handles has changed. j6_handle_t is now 32 bits, and
  a new j6_cap_t (also 32 bits) is added. Handles of a process are now a
  util::map<j6_handle_t, handle> where handle is a new struct containing
  the id, capabilities, and object pointer.
- The kernel object definition DSL gained a few changes to support auto
  generating the handle -> object conversion in the _syscall_verify_*
  functions, mostly knowing the object type, and an optional "cname"
  attribute on objects where their names differ from C++ code.
  (Specifically vma/vm_area)
- Kernel object code and other code under kernel/objects is now in a new
  obj:: namespace, because fuck you <cstdlib> for putting "system" in
  the global namespace. Why even have that header then?
- Kernel object types constructed with the construct_handle helper now
  have a creation_caps static member to declare what capabilities a
  newly created object's handle should have.

scripts/definitions/types/__init__.py

@@ -2,6 +2,7 @@ def _indent(x):
     from textwrap import indent
     return indent(str(x), '    ')
 
+class CName(str): pass
 class Description(str): pass
 class Import(str): pass
 

scripts/definitions/types/interface.py

@@ -30,7 +30,8 @@ class Interface:
         parts.extend(map(_indent, self.functions))
         return "\n".join(parts)
 
-    def __methods(self):
+    @property
+    def methods(self):
         mm = [(i, None, self.functions[i]) for i in range(len(self.functions))]
 
         base = len(mm)
@@ -39,5 +40,3 @@ class Interface:
             base += len(o.methods)
 
         return mm
-
-    methods = property(__methods)

scripts/definitions/types/object.py

@@ -2,13 +2,14 @@ from . import _indent
 from . import Options
 
 class Object:
-    def __init__(self, name, uid, typename=None, opts=Options(), desc="", children=tuple()):
+    def __init__(self, name, uid, typename=None, opts=Options(), desc="", children=tuple(), cname=None):
         self.name = name
         self.uid = uid
         self.options = opts
         self.desc = desc
         self.super = typename
         self.methods = children
+        self.cname = cname or name
 
         from . import ObjectRef
         self.__ref = ObjectRef(name)

scripts/definitions/types/objref.py

@@ -20,11 +20,10 @@ class ObjectRef(Type):
 
         if "list" in options:
             two = "size_t"
+            one = f"{one} *"
+
             if out:
-                one = f"const {one} *"
                 two += " *"
-            else:
-                one = f"{one} *"
             return ((one, ""), (two, "_count"))
 
         else:
@@ -33,7 +32,13 @@ class ObjectRef(Type):
             return ((one, ""),)
 
     def cxx_names(self, options):
-        return self.c_names(options)
+        if not self.needs_object(options):
+            return self.c_names(options)
+        return ((f"obj::{self.name} *", ""),)
+
+    def needs_object(self, options):
+        return not bool({"out", "inout", "list", "handle"}.intersection(options))
+
 
     @classmethod
     def connect(cls, objects):

scripts/definitions/types/type.py

@@ -11,3 +11,5 @@ class Type:
     def cxx_names(self, options):
         raise NotImplemented("Call to base Type.c_names")
 
+    def needs_object(self, options):
+        return False