Using ioctl to obtain serial number from ATA drive

driveserial.go

package main
    
import (
    "fmt"
    "os"
    "unsafe"
    "syscall"
)


const (
    HDIO_DRIVE_CMD = 0x031f // execute a special drive command 
)


const (
    WIN_IDENTIFY = 0xEC // ask drive to identify itself
)

const START_SERIAL = 10
const LENGTH_SERIAL = 10


func little_endian_to_big_endian(input []byte) []byte {
    output := make([]byte, len(input))

    for i := 0; i < len(input); i+=2 {
        output[i] = input[i + 1]
        output[i + 1] = input[i]
    }

    return output
}


func GetDiskSerial(device *os.File) string {
    buffer := make([]byte, 4 + 512) // Command definition + buffer for data
    buffer[0] = WIN_IDENTIFY
    buffer[3] = 1 // Buffer size in some internal struct sizes

    _, _, err := syscall.Syscall(syscall.SYS_IOCTL, uintptr(device.Fd()),
                              uintptr(HDIO_DRIVE_CMD), 
                              uintptr(unsafe.Pointer(&buffer[0])))

    if err != 0 {
        fmt.Println(err)
        return ""
    }

    serial := string(little_endian_to_big_endian(buffer[4 + START_SERIAL * 2: 2 + (START_SERIAL + LENGTH_SERIAL)*2])) 

    return serial
}


func main() {
    if len(os.Args) < 2 {
        fmt.Println("Usage: driveserial /path/to/disk/device")
        return
    }

    device, err := os.Open(os.Args[1])

    if err != nil {
        fmt.Println(err)
        return
    }

    fmt.Println(GetDiskSerial(device))
}