Function pipe_sddl 

pub fn pipe_sddl(sid: &str) -> String

SDDL for the daemon pipe’s DACL: protected (P, no inherited ACEs), granting GA (generic all) to SY (LocalSystem) and to the owning user’s SID — and to no one else, since a DACL denies anything it doesn’t grant. This is the named-pipe analog of the 0600 unix socket + uid peer check (#66). Remote access is separately refused via PIPE_REJECT_REMOTE_CLIENTS on the server, not the DACL.