From 9de775d7e7f9d7aaaa690c5b028cf8e204401507 Mon Sep 17 00:00:00 2001
From: Maxime Meignan <maxime.meignan@cellebrite.com>
Date: Tue, 8 Oct 2024 17:52:26 +0200
Subject: [PATCH] Implemented the GlobalVariable type change/monitoring

---
 libbs/decompilers/ida/compat.py    | 18 +++++++++++++++++-
 libbs/decompilers/ida/hooks.py     |  7 ++++++-
 libbs/decompilers/ida/interface.py |  8 +++++---
 3 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/libbs/decompilers/ida/compat.py b/libbs/decompilers/ida/compat.py
index 2a50fe3..3f810eb 100644
--- a/libbs/decompilers/ida/compat.py
+++ b/libbs/decompilers/ida/compat.py
@@ -1261,14 +1261,30 @@ def global_var(addr):
     if not name:
         return None
 
+    type_ = idc.get_type(addr)
     size = idaapi.get_item_size(addr)
-    return GlobalVariable(addr, name, size=size, last_change=datetime.datetime.now(tz=datetime.timezone.utc))
+    return GlobalVariable(addr, name, size=size, last_change=datetime.datetime.now(tz=datetime.timezone.utc), type_=type_)
 
 
 @execute_write
 def set_global_var_name(var_addr, name):
     return idaapi.set_name(var_addr, name)
 
+@execute_write
+def set_global_var_type(var_addr, type_str):
+    """
+    To make sure the type is correctly displayed (especially for arrays of structs, or arrayy of chars, a.k.a. strings),
+    we first undefine the items where the type is going to be applied.
+    Parse the applied type string to infer its size, and thus the number of bytes to undefine.
+    """
+    tif = convert_type_str_to_ida_type(type_str)
+    if tif is None:
+        idc.del_items(var_addr, flags=idc.DELIT_SIMPLE)
+    else:
+        type_size = tif.get_size()
+        idc.del_items(var_addr, flags=idc.DELIT_SIMPLE, nbytes=type_size)
+    return idc.SetType(var_addr, type_str)
+
 
 def ida_type_from_serialized(typ: bytes, fields: bytes):
     tif = ida_typeinf.tinfo_t()
diff --git a/libbs/decompilers/ida/hooks.py b/libbs/decompilers/ida/hooks.py
index f58374a..2576986 100644
--- a/libbs/decompilers/ida/hooks.py
+++ b/libbs/decompilers/ida/hooks.py
@@ -212,6 +212,11 @@ def ti_changed(self, ea, type_, fields):
                 self.interface.function_header_changed(
                     FunctionHeader(None, ea, type_=curr_ret_type, args={})
                 )
+        elif not pfn:
+            # Must be a global variable type change
+            self.interface.global_variable_changed(
+                GlobalVariable(addr=ea, name=idaapi.get_name(ea), size=idaapi.get_item_size(ea), type_=idc.get_type(ea))
+            )
 
         return 0
 
@@ -456,7 +461,7 @@ def renamed(self, ea, new_name, local_name):
         # symbols changing without any corresponding func is assumed to be global var
         if ida_func is None:
             self.interface.global_variable_changed(
-                GlobalVariable(ea, new_name, size=idaapi.get_item_size(ea))
+                GlobalVariable(ea, new_name, size=idaapi.get_item_size(ea), type_=idc.get_type(ea))
             )
         # function name renaming
         elif ida_func.start_ea == ea:
diff --git a/libbs/decompilers/ida/interface.py b/libbs/decompilers/ida/interface.py
index 70e0ac2..1f70b3a 100755
--- a/libbs/decompilers/ida/interface.py
+++ b/libbs/decompilers/ida/interface.py
@@ -299,11 +299,13 @@ def _set_stack_variable(self, svar: StackVariable, **kwargs) -> bool:
 
     # global variables
     def _set_global_variable(self, gvar: GlobalVariable, **kwargs) -> bool:
-        # TODO: needs type setting implementation!
+        modified = False
         if gvar.name:
-            return compat.set_global_var_name(gvar.addr, gvar.name)
+            modified |= compat.set_global_var_name(gvar.addr, gvar.name)
+        if gvar.type:
+            modified |= compat.set_global_var_type(gvar.addr, gvar.type)
 
-        return False
+        return modified
 
     def _get_global_var(self, addr) -> Optional[GlobalVariable]:
         return compat.global_var(addr)