#define _GNU_SOURCE
#include <fcntl.h>
#include <string.h>
#include <unistd.h>

int
main (void)
{
  char buf[36368];
  char abuf[sizeof buf]; memset (abuf, 'a', sizeof abuf);
  char bbuf[sizeof buf]; memset (bbuf, 'b', sizeof bbuf);
  int src = open ("src", O_WRONLY | O_CREAT | O_TRUNC, 0666);
  if (src < 0)
    return 2;
  if (write (src, abuf, sizeof buf) != sizeof buf)
    return 3;
  if (close (src) != 0)
    return 4;
  int dst = open ("dst", O_WRONLY | O_CREAT | O_TRUNC, 0666);
  if (dst < 0)
    return 5;
  if (write (dst, bbuf, sizeof buf) != sizeof buf)
    return 6;
  if (close (dst) != 0)
    return 7;
  src = open ("src", O_RDONLY);
  if (src < 0)
    return 8;
  dst = open ("dst", O_WRONLY);
  if (dst < 0)
    return 9;
  if (copy_file_range (src, 0, dst, 0, sizeof buf, 0) != sizeof buf)
    return 10;
  if (close (src) != 0)
    return 11;
  if (close (dst) != 0)
    return 12;
  dst = open ("dst", O_RDONLY);
  if (dst < 0)
    return 13;
  if (read (dst, buf, sizeof buf) != sizeof buf)
    return 14;
  if (memcmp (buf, abuf, sizeof buf) != 0)
    return 15;
  return 0;
}