How can I acquire a disk's identifier on Windows?

Question

How can I retrieve a disk's identifier on Windows? This is not to be confused with the volume identifier; they're two different things. The disk identifier is the 4-byte identifier that resides in the MBR (or 16-byte identifier if it uses GPT). If you run diskpart and query the details of a disk, it's the value labeled 'Disk ID'.

I've run through all of the MSDN documents that looked relevant, but I haven't managed to find anything capable of doing this; evidently it is possible, though, seeing as diskpart is able to get this value from somewhere.

I could always invoke diskpart as a last resort and parse it's output, but I'd really prefer to avoid doing that. Does anyone know how I can get this number programatically?

Answer 1

You can use the Win32_DiskDrive WMi class and the Signature property.

Check this sample App

#include "stdafx.h"
#define _WIN32_DCOM
#include <iostream>
using namespace std;
#include <comdef.h>
#include <Wbemidl.h>
# pragma comment(lib, "wbemuuid.lib")


#pragma argsused
int main(int argc, char* argv[])
{
    BSTR strNetworkResource;
    //To use a WMI remote connection set localconn to false and configure the values of the pszName, pszPwd and the name of the remote machine in strNetworkResource
    strNetworkResource = L"\\\\.\\root\\CIMV2";

    COAUTHIDENTITY *userAcct =  NULL ;
    COAUTHIDENTITY authIdent;

    // Initialize COM. ------------------------------------------

    HRESULT hres;
    hres =  CoInitializeEx(0, COINIT_MULTITHREADED);
    if (FAILED(hres))
    {
        cout << "Failed to initialize COM library. Error code = 0x" << hex << hres << endl;
        cout << _com_error(hres).ErrorMessage() << endl;
        cout << "press enter to exit" << endl;
        cin.get();      
        return 1;                  // Program has failed.
    }

    // Set general COM security levels --------------------------


        hres =  CoInitializeSecurity(
            NULL,
            -1,                          // COM authentication
            NULL,                        // Authentication services
            NULL,                        // Reserved
            RPC_C_AUTHN_LEVEL_DEFAULT,   // Default authentication
            RPC_C_IMP_LEVEL_IMPERSONATE, // Default Impersonation
            NULL,                        // Authentication info
            EOAC_NONE,                   // Additional capabilities
            NULL                         // Reserved
            );

    if (FAILED(hres))
    {
        cout << "Failed to initialize security. Error code = 0x" << hex << hres << endl;
        cout << _com_error(hres).ErrorMessage() << endl;
        CoUninitialize();
        cout << "press enter to exit" << endl;
        cin.get();      
        return 1;                    // Program has failed.
    }

    // Obtain the initial locator to WMI -------------------------

    IWbemLocator *pLoc = NULL;
    hres = CoCreateInstance(CLSID_WbemLocator, 0, CLSCTX_INPROC_SERVER, IID_IWbemLocator, (LPVOID *) &pLoc);

    if (FAILED(hres))
    {
        cout << "Failed to create IWbemLocator object." << " Err code = 0x" << hex << hres << endl;
        cout << _com_error(hres).ErrorMessage() << endl;
        CoUninitialize();       
        cout << "press enter to exit" << endl;
        cin.get();      
        return 1;                 // Program has failed.
    }

    // Connect to WMI through the IWbemLocator::ConnectServer method

    IWbemServices *pSvc = NULL;

        hres = pLoc->ConnectServer(
             _bstr_t(strNetworkResource),      // Object path of WMI namespace
             NULL,                    // User name. NULL = current user
             NULL,                    // User password. NULL = current
             0,                       // Locale. NULL indicates current
             NULL,                    // Security flags.
             0,                       // Authority (e.g. Kerberos)
             0,                       // Context object
             &pSvc                    // pointer to IWbemServices proxy
             );

    if (FAILED(hres))
    {
        cout << "Could not connect. Error code = 0x" << hex << hres << endl;    
        cout << _com_error(hres).ErrorMessage() << endl;
        pLoc->Release();
        CoUninitialize();
        cout << "press enter to exit" << endl;
        cin.get();          
        return 1;                // Program has failed.
    }

    cout << "Connected to root\\CIMV2 WMI namespace" << endl;

    // Set security levels on the proxy -------------------------
        hres = CoSetProxyBlanket(
           pSvc,                        // Indicates the proxy to set
           RPC_C_AUTHN_WINNT,           // RPC_C_AUTHN_xxx
           RPC_C_AUTHZ_NONE,            // RPC_C_AUTHZ_xxx
           NULL,                        // Server principal name
           RPC_C_AUTHN_LEVEL_CALL,      // RPC_C_AUTHN_LEVEL_xxx
           RPC_C_IMP_LEVEL_IMPERSONATE, // RPC_C_IMP_LEVEL_xxx
           NULL,                        // client identity
           EOAC_NONE                    // proxy capabilities
        );


    if (FAILED(hres))
    {
        cout << "Could not set proxy blanket. Error code = 0x" << hex << hres << endl;
        cout << _com_error(hres).ErrorMessage() << endl;
        pSvc->Release();
        pLoc->Release();
        CoUninitialize();
        cout << "press enter to exit" << endl;
        cin.get();      
        return 1;               // Program has failed.
    }

    // Use the IWbemServices pointer to make requests of WMI ----

    IEnumWbemClassObject* pEnumerator = NULL;
    hres = pSvc->ExecQuery( L"WQL", L"SELECT * FROM Win32_DiskDrive",
    WBEM_FLAG_FORWARD_ONLY | WBEM_FLAG_RETURN_IMMEDIATELY, NULL, &pEnumerator);

    if (FAILED(hres))
    {
        cout << "ExecQuery failed" << " Error code = 0x"    << hex << hres << endl;
        cout << _com_error(hres).ErrorMessage() << endl;
        pSvc->Release();
        pLoc->Release();
        CoUninitialize();
        cout << "press enter to exit" << endl;
        cin.get();      
        return 1;               // Program has failed.
    }

    // Secure the enumerator proxy


        hres = CoSetProxyBlanket(
            pEnumerator,                    // Indicates the proxy to set
            RPC_C_AUTHN_DEFAULT,            // RPC_C_AUTHN_xxx
            RPC_C_AUTHZ_DEFAULT,            // RPC_C_AUTHZ_xxx
            COLE_DEFAULT_PRINCIPAL,         // Server principal name
            RPC_C_AUTHN_LEVEL_PKT_PRIVACY,  // RPC_C_AUTHN_LEVEL_xxx
            RPC_C_IMP_LEVEL_IMPERSONATE,    // RPC_C_IMP_LEVEL_xxx
            userAcct,                       // client identity
            EOAC_NONE                       // proxy capabilities
            );



    // Get the data from the WQL sentence
    IWbemClassObject *pclsObj = NULL;
    ULONG uReturn = 0;

    while (pEnumerator)
    {
        HRESULT hr = pEnumerator->Next(WBEM_INFINITE, 1, &pclsObj, &uReturn);

        if(0 == uReturn || FAILED(hr))
          break;

        VARIANT vtProp;

                hr = pclsObj->Get(L"Name", 0, &vtProp, 0, 0);// String
                if (!FAILED(hr))
                {
                  if ((vtProp.vt==VT_NULL) || (vtProp.vt==VT_EMPTY))
                    wcout << "Name : " << ((vtProp.vt==VT_NULL) ? "NULL" : "EMPTY") << endl;
                  else
                  if ((vtProp.vt & VT_ARRAY))
                    wcout << "Name : " << "Array types not supported (yet)" << endl;
                  else
                    wcout << "Name : " << vtProp.bstrVal << endl;
                }
                VariantClear(&vtProp);

                hr = pclsObj->Get(L"Signature", 0, &vtProp, 0, 0);// Uint32
                if (!FAILED(hr))
                {
                  if ((vtProp.vt==VT_NULL) || (vtProp.vt==VT_EMPTY))
                    wcout << "Signature : " << ((vtProp.vt==VT_NULL) ? "NULL" : "EMPTY") << endl;                   
                  else
                  if ((vtProp.vt & VT_ARRAY))
                    wcout << "Signature : " << "Array types not supported (yet)" << endl;
                  else
                    wcout << "Signature : " << hex << vtProp.uintVal << endl;
                }
                VariantClear(&vtProp);


        pclsObj->Release();
        pclsObj=NULL;
    }

    // Cleanup

    pSvc->Release();
    pLoc->Release();
    pEnumerator->Release();
    if (pclsObj!=NULL)
     pclsObj->Release();

    CoUninitialize();
    cout << "press enter to exit" << endl;
    cin.get();
    return 0;   // Program successfully completed.
}

This code returns

And DiskPart