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// mach_override.h semver:1.2.0
// Copyright (c) 2003-2012 Jonathan 'Wolf' Rentzsch: http://rentzsch.com
// Some rights reserved: http://opensource.org/licenses/mit
// https://github.com/rentzsch/mach_override
#ifndef _mach_override_
#define _mach_override_
#include <sys/types.h>
#include <mach/error.h>
#define err_cannot_override (err_local|1)
__BEGIN_DECLS
/****************************************************************************************
Dynamically overrides the function implementation referenced by
originalFunctionAddress with the implentation pointed to by overrideFunctionAddress.
Optionally returns a pointer to a "reentry island" which, if jumped to, will resume
the original implementation.
@param originalFunctionAddress -> Required address of the function to
override (with overrideFunctionAddress).
@param overrideFunctionAddress -> Required address to the overriding
function.
@param originalFunctionReentryIsland <- Optional pointer to pointer to the
reentry island. Can be NULL.
@result <- err_cannot_override if the original
function's implementation begins with
the 'mfctr' instruction.
************************************************************************************/
mach_error_t
mach_override_ptr(
void *originalFunctionAddress,
const void *overrideFunctionAddress,
void **originalFunctionReentryIsland );
__END_DECLS
/****************************************************************************************
If you're using C++ this macro will ease the tedium of typedef'ing, naming, keeping
track of reentry islands and defining your override code. See test_mach_override.cp
for example usage.
************************************************************************************/
#ifdef __cplusplus
#define MACH_OVERRIDE( ORIGINAL_FUNCTION_RETURN_TYPE, ORIGINAL_FUNCTION_NAME, ORIGINAL_FUNCTION_ARGS, ERR ) \
{ \
static ORIGINAL_FUNCTION_RETURN_TYPE (*ORIGINAL_FUNCTION_NAME##_reenter)ORIGINAL_FUNCTION_ARGS; \
static bool ORIGINAL_FUNCTION_NAME##_overriden = false; \
class mach_override_class__##ORIGINAL_FUNCTION_NAME { \
public: \
static kern_return_t override(void *originalFunctionPtr) { \
kern_return_t result = err_none; \
if (!ORIGINAL_FUNCTION_NAME##_overriden) { \
ORIGINAL_FUNCTION_NAME##_overriden = true; \
result = mach_override_ptr( (void*)originalFunctionPtr, \
(void*)mach_override_class__##ORIGINAL_FUNCTION_NAME::replacement, \
(void**)&ORIGINAL_FUNCTION_NAME##_reenter ); \
} \
return result; \
} \
static ORIGINAL_FUNCTION_RETURN_TYPE replacement ORIGINAL_FUNCTION_ARGS {
#define END_MACH_OVERRIDE( ORIGINAL_FUNCTION_NAME ) \
} \
}; \
\
err = mach_override_class__##ORIGINAL_FUNCTION_NAME::override((void*)ORIGINAL_FUNCTION_NAME); \
}
#endif
#endif // _mach_override_
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