linux c 获取硬盘序列号

#include 
#include 
#include 
#include 
#include  

static int
getdiskid (char *hardc)
{
	int fd;
	struct hd_driveid hid;
	fd = open ("/dev/sda", O_RDONLY);
	if (fd < 0)
	{
		return -1;
	}
	if (ioctl (fd, HDIO_GET_IDENTITY, &hid) < 0)
	{
		return -1;
	}
	close (fd);
	sprintf(hardc,"%s", hid.serial_no);
	return 0;
}

int main(void)
{
                 char hardseri[50];
                 getdiskid(hardseri);
                 printf("%s",hardseri);
                 return 0;
}