Breno Leitao wrote: > Add support for getsockopt command (SOCKET_URING_OP_GETSOCKOPT), where > level is SOL_SOCKET. This is leveraging the sockptr_t infrastructure, > where a sockptr_t is either userspace or kernel space, and handled as > such. > > Function io_uring_cmd_getsockopt() is inspired by __sys_getsockopt(). > > Differently from the getsockopt(2), the optlen field is not a userspace > pointers. In getsockopt(2), userspace provides optlen pointer, which is > overwritten by the kernel. In this implementation, userspace passes a > u32, and the new value is returned in cqe->res. I.e., optlen is not a > pointer. > > Important to say that userspace needs to keep the pointer alive until > the CQE is completed. What bad things can happen otherwise? The kernel is not depending on a well behaved process for its correctness here, is it? Any user pages have to be pinned while kernel might refer to them, for instance. > Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>
