Method ModeSelect

cpp/devices/scsi_command_util.cpp:19–83

using namespace scsi_defs;

string scsi_command_util::ModeSelect(scsi_command cmd, cdb_t cdb, span<const uint8_t> buf, int length, int sector_size)
{
	assert(cmd == scsi_command::eCmdModeSelect6 || cmd == scsi_command::eCmdModeSelect10);
	assert(length >= 0);

	string result;

	// PF
	if (!(cdb[1] & 0x10)) {
		// Vendor-specific parameters (SCSI-1) are not supported.
		// Do not report an error in order to support Apple's HD SC Setup.
		return result;
	}

	// Skip block descriptors
	int offset;
	if (cmd == scsi_command::eCmdModeSelect10) {
		offset = 8 + GetInt16(buf, 6);
	}
	else {
		offset = 4 + buf[3];
	}
	length -= offset;

	bool has_valid_page_code = false;

	// Parse the pages
	while (length > 0) {
		// Format device page
		if (const int page = buf[offset]; page == 0x03) {
			if (length < 14) {
				throw scsi_exception(sense_key::illegal_request, asc::invalid_field_in_parameter_list);
			}

			// With this page the sector size for a subsequent FORMAT can be selected, but only very few
			// drives support this, e.g FUJITSU M2624S
			// We are fine as long as the current sector size remains unchanged
			if (GetInt16(buf, offset + 12) != sector_size) {
				// With piscsi it is not possible to permanently (by formatting) change the sector size,
				// because the size is an externally configurable setting only
				spdlog::warn("In order to change the sector size use the -b option when launching piscsi");
				throw scsi_exception(sense_key::illegal_request, asc::invalid_field_in_parameter_list);
			}

			has_valid_page_code = true;
		}
		else {
			stringstream s;
			s << "Unknown MODE SELECT page code: $" << setfill('0') << setw(2) << hex << page;
			result = s.str();
		}

		// Advance to the next page
		const int size = buf[offset + 1] + 2;

		length -= size;
		offset += size;
	}