static int get_blocksize(BlockDriverState *bdrv) { uint8_t cmd[10]; uint8_t buf[8]; uint8_t sensebuf[8]; sg_io_hdr_t io_header; int ret; memset(cmd, 0, sizeof(cmd)); memset(buf, 0, sizeof(buf)); cmd[0] = READ_CAPACITY_10; memset(&io_header, 0, sizeof(io_header)); io_header.interface_id = 'S'; io_header.dxfer_direction = SG_DXFER_FROM_DEV; io_header.dxfer_len = sizeof(buf); io_header.dxferp = buf; io_header.cmdp = cmd; io_header.cmd_len = sizeof(cmd); io_header.mx_sb_len = sizeof(sensebuf); io_header.sbp = sensebuf; io_header.timeout = 6000; /* XXX */ ret = bdrv_ioctl(bdrv, SG_IO, &io_header); if (ret < 0) return -1; return (buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7]; }