princ_to_value
ret = princ_to_value(state->s4u2self_user, obj, AU_REQ_S4U2S_USER);
ret = princ_to_value(req->second_ticket[0]->enc_part2->client,
ret = princ_to_value(req->second_ticket[0]->enc_part2->client,
princ_to_value(krb5_principal princ, k5_json_object obj, const char *key);
ret = princ_to_value(req->client, obj, AU_REQ_CLIENT);
ret = princ_to_value(req->server, obj, AU_REQ_SERVER);
ret = princ_to_value(tkt->server, tmp, AU_CNAME);
ret = princ_to_value(tkt->server, tmp, AU_SNAME);
ret = princ_to_value(part2->client, tmp, AU_CNAME);