void *copyin(uintptr_t addr, size_t size)

The copyin function copies the specified size in bytes from the specified user address (addr) into a DTrace scratch buffer and returns the address of this buffer. The user address is interpreted as an address in the space of the process that is associated with the current thread. The resulting buffer pointer is guaranteed to have 8-byte alignment. The address in question must correspond to a faulted-in page in the current process. If the address does not correspond to a faulted-in page, or if insufficient scratch memory is available, NULL is returned and an error is generated.