Add string as a primitve to struct defs

Author: r41k0u

examples/execve5.py

@@ -10,6 +10,7 @@
 class data_t:
     pid: c_uint64
     ts: c_uint64
+    comm: str(16)
 
 
 @bpf

pythonbpf/structs_pass.py

@@ -28,14 +28,25 @@ def process_bpf_struct(cls_node, module):
 
     for item in cls_node.body:
         if isinstance(item, ast.AnnAssign) and isinstance(item.target, ast.Name):
+            print(f"Field: {item.target.id}, Type: "
+                  f"{ast.dump(item.annotation)}")
             field_names.append(item.target.id)
-            field_types.append(ctypes_to_ir(item.annotation.id))
+            if isinstance(item.annotation, ast.Call) and isinstance(item.annotation.func, ast.Name) and item.annotation.func.id == "str":
+                # This is a char array with fixed length
+                # TODO: For now assuming str is always called with constant
+                field_types.append(ir.ArrayType(
+                    ir.IntType(8), item.annotation.args[0].value))
+            else:
+                field_types.append(ctypes_to_ir(item.annotation.id))
 
     curr_offset = 0
     for ftype in field_types:
         if isinstance(ftype, ir.IntType):
             fsize = ftype.width // 8
             alignment = fsize
+        elif isinstance(ftype, ir.ArrayType):
+            fsize = ftype.count * (ftype.element.width // 8)
+            alignment = ftype.element.width // 8
         elif isinstance(ftype, ir.PointerType):
             fsize = 8
             alignment = 8