Mprotect API for OS X Tiger

Question

I am trying to use the mprotect API on MacOSX 10.4 (tiger), I tried in every possible way, I know it always returns -1, with errno 13, which means "permission denied" while I try to add write to some executable code.

The same code definitely works on MacOS X 10.5 (leopard).

the code is pretty simple

int ret = mprotect((void*)pFunc, 4096, PROT_WRITE | PROT_EXEC);

where pFunc is the address of any function loaded into the address space of the process. I tried to remove PROT_EXEC before adding the PROT_WRITE permission, but no luck. I also tried aligning pFunc with the page size of the memory, no luck either ...

Any idea how to do this?

Answer 1

, mmap'd ? man mprotect ( Linux), -, , (PROT_WRITE) .

Answer 2

OSX. , Mach vm_protect?

Answer 3

. , ?

, , . ?

Answer 4

. EXEC WRITE. , write + exec .

, WRITE, EXEC.