A simple Golang function for getting Windows's SMBIOS UUID.

getSmbiosUuid.go

package main

import (
	"fmt"
	"syscall"
	"unsafe"
)

const (
	RSMB = 0x52534D42
)

var (
	libKernel32                = syscall.NewLazyDLL("kernel32.dll")
	procGetSystemFirmwareTable = libKernel32.NewProc("GetSystemFirmwareTable").Addr()
)

func getSmbiosUuid() (string, error) {
	bufferSize, _, err := syscall.SyscallN(procGetSystemFirmwareTable, RSMB, 0, 0, 0)
	if bufferSize == 0 {
		return "", fmt.Errorf("failed to get buffer size: %w", err)
	} else if bufferSize < 8 {
		return "", fmt.Errorf("buffer size unexpected: expected >= 8 bytes, received %d bytes", bufferSize)
	}

	buffer := make([]byte, bufferSize)
	bufferSize, _, err = syscall.SyscallN(procGetSystemFirmwareTable, RSMB, 0, uintptr(unsafe.Pointer(&buffer[0])), bufferSize)
	if bufferSize == 0 {
		return "", fmt.Errorf("failed to get buffer data: %w", err)
	} else if bufferSize != uintptr(len(buffer)) {
		return "", fmt.Errorf("buffer size mismatched: expected %d bytes, received %d bytes", uintptr(len(buffer)), bufferSize)
	}

	for offset := 8; offset < len(buffer); {
		structureType := buffer[offset]
		structureLength := int(buffer[offset+1])
		if structureType == 1 {
			if structureLength >= 24 {
				return fmt.Sprintf(
					"%02X%02X%02X%02X-%02X%02X-%02X%02X-%02X%02X-%02X%02X%02X%02X%02X%02X",
					buffer[offset+11], buffer[offset+10], buffer[offset+9], buffer[offset+8], buffer[offset+13], buffer[offset+12], buffer[offset+15], buffer[offset+14],
					buffer[offset+16], buffer[offset+17], buffer[offset+18], buffer[offset+19], buffer[offset+20], buffer[offset+21], buffer[offset+22], buffer[offset+23],
				), nil
			} else {
				return "", fmt.Errorf("failed to get BIOS UUID: UUID field not found")
			}
		} else if structureType == 127 {
			return "", fmt.Errorf("failed to get BIOS UUID: System Information structure not found")
		}
		for offset += structureLength + 2; offset < len(buffer); offset++ {
			if buffer[offset-1] == 0x00 && buffer[offset-2] == 0x00 {
				break
			}
		}
	}

	return "", fmt.Errorf("failed to get BIOS UUID: structure not found or invalid buffer")
}