#include <sys/types.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>

int main(int argc, char**argv)
{
  unsigned char buffer[512];
  int fildes;
  /* Use a bigger value if your HD is bigger than 1 TB */
  off_t too_far=(off_t)1024*1024*1024*1024;
  if(argc==1)
  {
    printf("%s device_to_read\n", argv[1]);
    printf("ie: %s /dev/sda\n", argv[1]);
    return 1;
  }
  fildes=open(argv[1], O_RDONLY|O_BINARY);
  if(fildes==-1)
  {
    printf("Can't read %s\n", argv[1]);
  }
  {
    /* Test 1*/
    printf("lseek 0 (should be OK): ");
    if(lseek(fildes, 0, SEEK_SET)==(off_t)(-1))
    {
      printf("Failed\n");
      return 1;
    }
    else
      printf("OK\n");
    /* Test 2*/
    printf("pread 0 (should be OK): ");
    if(pread(fildes, buffer, 512, 0)==(-1))
    {
      printf("Failed\n");
      return 1;
    }
    else
      printf("OK\n");
    /* Test 3: Go at the end of the disk */
    printf("lseek after the end of the disk (should be Failed): ");
    if(lseek(fildes, too_far, SEEK_SET)==(off_t)(-1))
      printf("Failed\n");
    else
    {
      printf("OK\n");
      printf("You must use a device, not a file\n");
      return 1;
    }
    /* Test 4*/
    printf("pread 0 (should be OK): ");
    if(pread(fildes, buffer, 512, 0)==(-1))
      printf("Failed <= BUG\n");
    else
      printf("OK\n");
    close(fildes);
  }
  return 0;
}