#include <termios.h>
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <errno.h>

int main(void) {
  struct termios ti;
  int nullfd = open("/dev/null", O_RDWR);
  int termfd = fileno(stdin); /* stdin: intended to be run in a terminal */
  int err;

  if (nullfd < 0) {
    perror("NA: null open failed");
    exit(1);
  }

  errno = 0;
  if (tcgetattr(nullfd, &ti) < 0) {
    err = errno;
    printf("OK: tcgetattr on /dev/null failed as expected\n");
    if (err != ENOTTY) {
      perror("FAIL: tcgetattr on /dev/null set errno incorrectly");
    }
  }
  else {
    printf("FAIL: tcgetattr on /dev/null succeeded\n");
  }

  errno = 0;
  if (tcgetattr(termfd, &ti) < 0) {
    perror("NA: tcgetattr failed");
    exit(1);
  }

  errno = 0;
  if (tcsetattr(nullfd, TCSADRAIN, &ti) == 0) {
    perror("FAIL: tcsetattr succeeded unexpectedly");
    exit(1);
  }
  err = errno;
  printf("OK: tcsetattr failed as expected\n");
  if (err != ENOTTY) {
    perror("FAIL: tcsetattr failure set errno incorrectly");
    exit(1);
  }

  return 0;
}