Page History

/*  Code intended to run with elevated privileges   */

/* Temporarily drop privileges */
if (seteuid(getuid()) != 0) {
  /* Handle error */
}

/*  Code intended to run with lower privileges  */

if (need_more_privileges) {
  /* Restore privileges */
  if (seteuid(0) != 0) {
    /* Handle Error */
  }

  /*  Code intended to run with elevated privileges   */
}

/* ... */

/* Permanently drop privileges */
if (setuid(getuid()) != 0) {
  /* Handle Error */
}

/*  
 * Code intended to run with lower privileges,
   * but if privilege relinquishment failed,
   * attacker couldcan regain elevated privileges! 
 */