Here's our usage: https://github.com/FRRouting/frr/blob/master/lib/privs.h#L141-L146 https://github.com/FRRouting/frr/blob/master/lib/privs.h#L14... #define

Here's our usage: https://github.com/FRRouting/frr/blob/master/lib/privs.h#L141-L146 https://github.com/FRRouting/frr/blob/master/lib/privs.h#L14... #define frr_with_privs(privs) \ for (struct zebra_privs_t *_once = NULL, \ *_privs __attribute__( \ (unused, cleanup(_zprivs_lower))) = \ _zprivs_raise(privs, __func__); \ _once == NULL; _once = (void *)1) This gives us a block construct that guarantees elevated privileges are dropped when the block is done: frr_with_privs(privs) { ... whatever ... break; /* exit block, drop privileges */ return; /* return, drop privileges */ }