getVersion.ts

import Transport from "@ledgerhq/hw-transport";
import { FirmwareInfo } from "../types/manager";

/**
 * Retrieve targetId and firmware version from device
 */

export default async function getVersion(
  transport: Transport
): Promise<FirmwareInfo> {
  const res = await transport.send(0xe0, 0x01, 0x00, 0x00);
  const data = res.slice(0, res.length - 2);
  let i = 0;

  // parse the target id of either BL or SE
  const targetId = data.readUIntBE(0, 4);
  i += 4;

  // parse the version of either BL or SE
  const rawVersionLength = data[i++];
  let rawVersion = data.slice(i, i + rawVersionLength).toString();
  i += rawVersionLength;

  // flags. gives information about manager allowed in SE mode.
  const flagsLength = data[i++];
  let flags = data.slice(i, i + flagsLength);
  i += flagsLength;

  if (!rawVersionLength) {
    // To support old firmware like bootloader of 1.3.1
    rawVersion = "0.0.0";
    flags = Buffer.allocUnsafeSlow(0);
  }

  let mcuVersion = "";
  let mcuBlVersion: string | undefined;
  let seVersion: string | undefined;
  let mcuTargetId: number | undefined;
  let seTargetId: number | undefined;

  const isBootloader = (targetId & 0xf0000000) !== 0x30000000;

  if (isBootloader) {
    mcuBlVersion = rawVersion;
    mcuTargetId = targetId;

    if (i < data.length) {
      // se part 1
      const part1Length = data[i++];
      const part1 = data.slice(i, i + part1Length);
      i += part1Length;

      // at this time, this is how we branch old & new format
      if (part1Length >= 5) {
        seVersion = part1.toString();
        // se part 2
        const part2Length = data[i++];
        const part2 = data.slice(i, i + part2Length);
        i += flagsLength;
        seTargetId = part2.readUIntBE(0, 4);
      } else {
        seTargetId = part1.readUIntBE(0, 4);
      }
    }
  } else {
    seVersion = rawVersion;
    seTargetId = targetId;

    // if SE: mcu version
    const mcuVersionLength = data[i++];
    let mcuVersionBuf: Buffer = Buffer.from(
      data.slice(i, i + mcuVersionLength)
    );
    i += mcuVersionLength;

    if (mcuVersionBuf[mcuVersionBuf.length - 1] === 0) {
      mcuVersionBuf = mcuVersionBuf.slice(0, mcuVersionBuf.length - 1);
    }
    mcuVersion = mcuVersionBuf.toString();
  }

  return {
    isBootloader,
    rawVersion,
    targetId,
    seVersion,
    mcuVersion,
    mcuBlVersion,
    mcuTargetId,
    seTargetId,
    flags,
  };
}