Interpose C function defined as function pointer inside a structure

Question

Good morning,

Is it possible, using dyld interposition feature, to interpose this kind of C function ?

typedef struct aStructure {
    IOReturn (*aCfunction)(void *self, UInt32 integer); // self is a 
                                                        // pointer to aStructure
} aStructure;

How the function is called:

aStructure **myStruct = ......;

(*myStruct)->aCfunction(myStruct, 1);

have you figured this out? i have similar question: https://stackoverflow.com/questions/53535716/interpose-c-struct-function-pointer-macos — danylokos, Nov 29 '18 at 09:30

score 0 · Accepted Answer · answered Aug 21 '12 at 09:45

0

Probably only possible if you can figure out where the actual function is, and interpose that.

There will be code to initialize the function pointer field in the structure to point at an actual function and I guess that's where you need to change things.

Also, you calling line is slighly off, it needs to be

(*myStruct)->aCfunction(*myStruct, 1);

answered Aug 21 '12 at 09:45

unwind

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after some gdb magic, it appears that these C function pointers are wrappers for C++ methods. It's going to be easier now. Nonetheless, I'm right about the function call (I follow Apple docs ) – b1onic Aug 24 '12 at 19:38

Interpose C function defined as function pointer inside a structure

1 Answers1