if (cap_rights_limit(dirfd, CAP_CREATE | CAP_WRITE | CAP_FTRUNCATE | CAP_SEEK | CAP_LOOKUP | CAP_FSTAT) < 0 && errno != ENOSYS) {
     syslog(LOG_WARNING, "cap_rights_limit: %m");
     exit(1);
}
if (cap_enter() < 0 && errno != ENOSYS) {
     syslog(LOG_ERR, "cap_enter: %m");
     exit(1);
}