IDA SDK - Rename Variable permanently

Question

I'm using ida 6.8 SDK and i have an problem with saving changed variables names,

I used many functions like set_reg_name(C++), setMemberName(in python), they change the name but not permanently, after pressing refresh , or reopening ida, the variables have old names.

What function is used when u press "N" Rename Iyvar, and were to get info on correct way of saving changed variable names ?

Answer 1

Solution is very simple:

1. get pointer to pseudoview

   vdui_t * vuu= open_pseudocode(func->startEA, 0);

2. Get Pointer to variables

   lvars_t& lvars = *pFunction->get_lvars();

3. Simply rename variable

   vuu->rename_lvar(&lvars.at(i), "permanamed", true);

last bool flag in rename_lvar func, operate if renaming is permanent or not .

p.s. Its kind'a bad solution as it require opening pseudo view, but i didn't find any other way to do it permanently , or similiar, working function that set's flag like in rename_lvar func .

Answer 2

Excellent work @LighFusion and @bravosierra99. Since I ended up here after looking for the Python solution, I'll paste it for anybody else.

widget = ida_kernwin.find_widget('Pseudocode-Y') 
vu = ida_hexrays.get_widget_vdui(widget) 
vu.rename_lvar(vu.cfunc.lvars[2], "pModelInfo", 1)

@Igor Skochinsky -- I just think it would just be common decency to make source or documentation available regarding how the existing basic [context] menu functionality works, so people have something to build on. I can't count the number of times I've been unable to fully replicate some basic inbuilt menu option, watching scripts constantly fail when I can manually perform the operation and it works perfectly.

Here's a more complete example:

def rename_lvar(src, dst, ea):
    #  if you want to use an existing view:
    #      widget = ida_kernwin.find_widget('Pseudocode-Y')
    #      vu = ida_hexrays.get_widget_vdui(widget)
    func = idaapi.get_func(ea)
    if func:
        ea = func.start_ea
        vu = idaapi.open_pseudocode(ea, 0)
        lvars = [n for n in vu.cfunc.lvars if n.name == src]
        if len(lvars) == 1:
            print("renaming {} to {}".format(lvars[0].name, dst))
            vu.rename_lvar(lvars[0], dst, 1)
            # how to close the view without a widget object?
            #     idautils.close_pseudocode (nope)
            #     ida_kerwin.close_widget   (nope)
        else:
            print("couldn't find var {}".format(src))

Answer 3

It's better to do this directly, without using the user-interface class vdui_t. Here's a small function you can call to set the name of a local variable, assuming you already have the lvar_t object you want to rename:

def SetLvarName(func_ea,lvar,name):
    lsi = ida_hexrays.lvar_saved_info_t()
    lsi.ll = lvar
    lsi.name = name
    ida_hexrays.modify_user_lvar_info(func_ea, ida_hexrays.MLI_NAME, lsi)

Here's a little harness I wrote to ensure it works. It decompiles some function in my database, finds the lvar_t named "v35", and renames it to "vNewName".

def GetCfunc(ea):
    f = idaapi.get_func(ea)
    if f is None:
        return None

    # Decompile the function.
    cfunc = None
    try:
        cfunc = idaapi.decompile(f)
    finally:
        return cfunc

cfunc = GetCfunc(0x61FE5DDE)
if cfunc:
    mba = cfunc.mba
    for idx in xrange(mba.vars.size()):
        var = mba.vars[idx]
        if var.name == "v35":
            SetLvarName(cfunc.entry_ea,var,"vNewName")
            break