An example program, using mprotect call to change rights on memory, writes some opcodes and launches them.

void* mapWritableMemory(int length, void** deleteptr)
Method creates about 8192 + length bytes memory, changes access rights to +rwx on length of them.
Arguments:

• length - count bytes to prepare
• deleteptr - pointer to voidptr, receives address of the whole mapped memory area (not only executable area) or NULL on error

Return value:

• address of the first of length bytes of executable memory or NULL on error

Mapped memory must be free()-d by hand, using deleteptr, not return value!

It was a very interesting theme for me, but I didn't find anything like that, so I had to do that by hands.
Daniel Rempel danil.rempel@gmail.com, 2014.