Getting function arguments in ida

Question

I'm trying to extract the callee arguments in my intel x86 binary using IDA Pro 7.3. I tried the following line:

ida_typeinf.get_arg_addrs(call_address)  # call address points at `call some_func`

For some reason, the call always returns None. Is there any other way to do this?

Answer 1

Okay that's our sample code:

.text:0000000180002953                 lea     rcx, aSmiGetplatform ; "SMI_GetPlatformInfo"
.text:000000018000295A                 mov     r12b, 0FFh
.text:000000018000295D                 mov     ebx, 0FFFFh
.text:0000000180002962                 call    DBG_Func

Ida Python shell we enter:

Python> type ( idaapi.get_arg_addrs( 0x180002962 ) )
<class 'NoneType'>

And there it is That 'none' is the problem. Let's fix it.

Place cursor in 'DBG_Func' and press 'y' (or click Edit/Functions/Set Type) it says:

void __fastcall DBG_Func();

Isn't DBG_Func supposed to receive and argument? Well so the function type definition is wrong. Change it to

void __fastcall DBG_Func(char *FunctionNameText);

and now test it again

Python> type (idaapi.get_arg_addrs( 0x180002962 ))
<class 'list'>

or

Python> idaapi.get_arg_addrs( 0x180002962 )
[0x180002953]

Wow finally problem solved! At 0x180002953 there is the argument that is passed to the call.

Answer 2

I have found out that if in the disassembler you give the type to the function that is being called, then the ida python function will work as it should.