wip

1 files changed, 59 insertions, 17 deletions

diff --git a/net9p_defs.gen b/net9p_defs.gen
index 0e75e42..8e8fe27 100755
--- a/net9p_defs.gen
+++ b/net9p_defs.gen
@@ -240,43 +240,85 @@ def gen_c_check_net_len(msg: Message) -> str:
         ret += "\t\treturn -EINVAL;\n"
         return ret
 
-    ret += f"\tuint64_t net_offset = 0;\n"
-    static_acc = 0
-    def _gen_c_check_net_len(prefix: str, struct: Struct | Message) -> str:
+    def has_big_list(typ: Atom | Struct | List | Message) -> bool:
+        match typ:
+            case Atom.u8:
+                return False
+            case Atom.u16:
+                return False
+            case Atom.u32:
+                return False
+            case Atom.u64:
+                return False
+            case Struct() | Message():
+                return any(has_big_list(member.typ) for member in typ.members)
+            case List():
+                sz = static_net_size(typ.typ)
+                if sz is None:
+                    return False
+                return sz > 1
+            case _:
+                raise ValueError(f"not a type: {typ.__class__.__name__}")
+
+    inited: bool = False
+    static_acc: int = 0
+    static_acc_name: list[str] = []
+    def _gen_c_check_net_len(wsprefix: str, nameprefix: str, struct: Struct | Message) -> str:
+        nonlocal inited
         nonlocal static_acc
+        nonlocal static_acc_name
         ret: str = ""
-    
+
+        if has_big_list(struct):
+            ret += f"{wsprefix}uint32_t sizeof_array;\n"
         prev_size: int = 0
         for member in struct.members:
             if (sz := static_net_size(member.typ)) is not None:
+                static_acc_name += [nameprefix+member.name]
                 static_acc += sz
                 prev_size = sz
             elif isinstance(member.typ, Struct):
-                ret += _gen_c_check_net_len(prefix, member.typ)
+                ret += _gen_c_check_net_len(wsprefix, nameprefix+member.name+'.', member.typ)
             elif isinstance(member.typ, List):
-                if static_acc:
-                    ret += f"{prefix}net_offset += {static_acc};\n"
+                if not inited:
+                    ret += f"{wsprefix}uint32_t calced_net_len = {static_acc};"
+                    if static_acc:
+                        ret += f" /* {', '.join(static_acc_name)} */"
+                    ret += "\n"
+                    static_acc_name = []
+                    static_acc = 0
+                    inited = True
+                elif static_acc:
+                    ret += f"{wsprefix}if (__builtin_add_overflow(calced_net_len, {static_acc}, &calced_net_len)) return -EWRONGLEN; /* {', '.join(static_acc_name)} */\n"
+                    static_acc_name = []
                     static_acc = 0
-                ret += f"{prefix}if ((uint64_t)net_len < net_offset)\n"
-                ret += f"{prefix}\treturn -EINVAL;\n"
+                ret += f"{wsprefix}/* {nameprefix}{member.name} */\n"
+                ret += f"{wsprefix}if (net_len < calced_net_len) return -EWRONGLEN;\n"
                 if (sz := static_net_size(member.typ.typ)) is not None:
-                    ret += f"{prefix}net_offset += unmarshal_u{prev_size*8}le(&net_bytes[net_offset-{prev_size}])*{sz};\n"
+                    if sz == 1:
+                        ret += f"{wsprefix}if (__builtin_add_overflow(calced_net_len, unmarshal_u{prev_size*8}le(&net_bytes[calced_net_len-{prev_size}]), &calced_net_len))\n"
+                    else:
+                        ret += f"{wsprefix}if (__builtin_mul_overflow(unmarshal_u{prev_size*8}le(&net_bytes[calced_net_len-{prev_size}]), {sz}, &sizeof_array)\n"
+                        ret += f"{wsprefix} || __builtin_add_overflow(calced_net_len, sizeof_array, &calced_net_len)\n"
+                    ret += f"{wsprefix}\treturn -EWRONGLEN;\n"
                 else:
                     assert isinstance(member.typ.typ, Struct)
-                    ret += f"{prefix}for (uint{prev_size*8}_t i, cnt = 0, unmarshal_u{prev_size*8}le(&net_bytes[net_offset-{prev_size}]); i < cnt; i++) {{\n"
-                    ret += _gen_c_check_net_len(prefix + "\t", member.typ.typ)
+                    ret += f"{wsprefix}for (uint{prev_size*8}_t i, cnt = 0, unmarshal_u{prev_size*8}le(&net_bytes[calced_net_len-{prev_size}]); i < cnt; i++) {{\n"
+                    ret += _gen_c_check_net_len(wsprefix + "\t", nameprefix+member.name+'[i].', member.typ.typ)
                     if static_acc:
-                        ret += f"{prefix}net_offset += {static_acc};\n"
+                        ret += f"{wsprefix}\tif (__builtin_add_overflow(calced_net_len, {static_acc}, &calced_net_len)) return -EWRONGLEN; /* {', '.join(static_acc_name)} */\n"
+                        static_acc_name = []
                         static_acc = 0
-                    ret += f"{prefix}\n"
+                    ret += f"{wsprefix}\n"
             else:
                 raise ValueError(f"not a type: {member.typ.__class__.__name__}")
     
         return ret
-    ret += _gen_c_check_net_len("\t", msg)
+    ret += _gen_c_check_net_len('\t', '.', msg)
     if static_acc:
-        ret += f"\tnet_offset += {static_acc};\n"
-    ret += "\tif ((uint64_t)net_len != net_offset)\n"
+        ret += f"\tcalced_net_len += {static_acc}; /* {', '.join(static_acc_name)} */\n"
+    ret += "\t/* final check */\n"
+    ret += "\tif (net_len != calced_net_len)\n"
     ret += "\t\treturn -EINVAL;\n"
     return ret