Programming

fd = open("/dev/sda", O_WRONLY);

write(fd,buff,512);

int writesector(const uint64_t offset, const int fd, const uint8_t *mybuff, const uint16_t len)
{
 if(!fd)
  {
    return 4;
  }
  errno = 0;
  if(lseek64(fd, offset, SEEK_SET) != -1)
  {
    if (errno!=0)
    {
      return 1;
    }
    
    errno = 0;
    
    if( (write(fd, mybuff, len)) != len)
    {
      return 1;
    }
    
    if (errno!=0)
    {
      return 1;
    }
  }
  else
  {
    return 2;
  }
  return 0;
}

int writesector(const uint64_t offset, const int fd, const uint8_t *mybuff, const uint16_t len)
{
	if(!fd)
  {
    return 4;
  }
  errno = 0;
  if(lseek64(fd, offset, SEEK_SET) != -1)
  {
    if (errno!=0)
    {
      return 1;
    }
    
    errno = 0;
    
    if( (write(fd, mybuff, len)) != len)
    {
      return 1;
    }
    
    if (errno!=0)
    {
      return 1;
    }
    
    if(fsync(fd)!=0)
    {
      return 1;
    }
    //sync();
  }
  else
  {
    return 2;
  }

  return 0;
}

      diskdata = memalign(512,PATTERN_LEN);

    	if(diskdata == NULL)
    	{
    		printf("FATAL ERROR: Unable to allocate memory for write buffer!\n");
    		exit (0);
    	}

      memset(diskdata,0,PATTERN_LEN);

handle = open64(devicename, O_WRONLY | O_DIRECT | O_SYNC);

#define _LARGEFILE64_SOURCE
#define _GNU_SOURCE