Mem leak in /dev/shm

fails in 30-min with write().c

static int capture_file_write()
{
  int fd;
  int error_check;
  static int buffer_counter = 0;
  char filename[256];

  snprintf(filename, sizeof filename, "%scapture.output.%02d.dat", DATA_PATH, buffer_counter);
  buffer_counter = (buffer_counter + 1) % 14;

  unlink(filename); //just unlink the file to make sure we write a fresh new file.

  fd = open(filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
  if(-1 == fd)
  {
    perror("Opened bad file desciptor " DATA_PATH "capture.output.dat");
  }

  error_check = write(fd, capture_stream, CAPTURE_DATA_SIZE);
  if (CAPTURE_DATA_SIZE != error_check)
  {
    if (-1 == error_check)
    {
      perror("capture file write failed.");
    }
    else
    {
      fprintf(stderr, "wrote the wrong number of bytes to the capture file. Wrote %d, expected to write %d", error_check, CAPTURE_DATA_SIZE);
    }
    exit(EXIT_FAILURE);
  }

  if(0 != close(fd))
  {
    perror("Failed to close capture output file");
    exit(EXIT_FAILURE);
  }

  return 0;
}

fails in 8-hours with mmap.c

static int capture_file_write()
{
  struct stat sb;
  void* p;
  int fd;
  int status;
  static int buffer_counter = 0;
  char filename[256];

  snprintf(filename, sizeof filename, "%scapture.output.%02d.dat", DATA_PATH, buffer_counter);
  buffer_counter = (buffer_counter + 1) % 14;

  unlink(filename); //just unlink the file to make sure we write a fresh new file.

  fd = open(filename, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
  if(-1 == fd)
  {
    perror("Opened bad file desciptor " DATA_PATH "capture.output.dat");
  }

  if (0 != ftruncate(fd, CAPTURE_DATA_SIZE))
  {
    perror("Failed to truncate capture output file");
    exit(EXIT_FAILURE);
  }

  status = fstat(fd, &sb);
  if(0 != status)
  {
    perror("Failed to fstat capture output file");
    exit(EXIT_FAILURE);
  }

  p = mmap(0, sb.st_size, PROT_WRITE, MAP_SHARED, fd, 0);
  if (MAP_FAILED == p)
  {
    perror("mmap");
    exit(EXIT_FAILURE);
  }

  memcpy(p, capture_stream, CAPTURE_DATA_SIZE);

  status = munmap(p, sb.st_size);
  if(0 != status)
  {
    perror("Failed to unmap capture output file");
    exit(EXIT_FAILURE);
  }

  status = close(fd);
  if(0 != status)
  {
    perror("Failed to close capture output file");
    exit(EXIT_FAILURE);
  }

  return 0;
}