+ union {
+ struct cmsghdr cmsghdr;
+ uint8_t buf[CMSG_SPACE(sizeof(struct ucred))];
+ } control;
+ struct ucred *ucred;
+
+ zero(control);
+ control.cmsghdr.cmsg_level = SOL_SOCKET;
+ control.cmsghdr.cmsg_type = SCM_CREDENTIALS;
+ control.cmsghdr.cmsg_len = CMSG_LEN(sizeof(struct ucred));
+
+ ucred = (struct ucred*) CMSG_DATA(&control.cmsghdr);
+ ucred->pid = s->pid;
+ ucred->uid = s->uid;
+ ucred->gid = s->gid;