DevCon update命令实现

int cmdUpdate(_In_ LPCTSTR BaseName, _In_opt_ LPCTSTR Machine, _In_ DWORD Flags, _In_ int argc, _In_reads_(argc) PTSTR argv[])
/*++

Routine Description:
    UPDATE
    update driver for existing device(s)

Arguments:

    BaseName  - name of executable
    Machine   - machine name, must be NULL
    argc/argv - remaining parameters

Return Value:

    EXIT_xxxx

--*/
{
    HMODULE newdevMod = NULL;
    int failcode = EXIT_FAIL;
    UpdateDriverForPlugAndPlayDevicesProto UpdateFn;
    BOOL reboot = FALSE;
    LPCTSTR hwid = NULL;
    LPCTSTR inf = NULL;
    DWORD flags = 0;
    DWORD res;
    TCHAR InfPath[MAX_PATH];

    UNREFERENCED_PARAMETER(BaseName);
    UNREFERENCED_PARAMETER(Flags);

    if(Machine) {
        //
        // must be local machine
        //
        return EXIT_USAGE;
    }
    if(argc<2) {
        //
        // at least HWID required
        //
        return EXIT_USAGE;
    }
    inf = argv[0];
    if(!inf[0]) {
        return EXIT_USAGE;
    }

    hwid = argv[1];
    if(!hwid[0]) {
        return EXIT_USAGE;
    }
    //
    // Inf must be a full pathname
    //
    res = GetFullPathName(inf,MAX_PATH,InfPath,NULL);
    if((res >= MAX_PATH) || (res == 0)) {
        //
        // inf pathname too long
        //
        return EXIT_FAIL;
    }
    if(GetFileAttributes(InfPath)==(DWORD)(-1)) {
        //
        // inf doesn't exist
        //
        return EXIT_FAIL;
    }
    inf = InfPath;
    flags |= INSTALLFLAG_FORCE;

    //
    // make use of UpdateDriverForPlugAndPlayDevices
    //
    newdevMod = LoadLibrary(TEXT("newdev.dll"));
    if(!newdevMod) {
        goto final;
    }
    UpdateFn = (UpdateDriverForPlugAndPlayDevicesProto)GetProcAddress(newdevMod,UPDATEDRIVERFORPLUGANDPLAYDEVICES);
    if(!UpdateFn)
    {
        goto final;
    }

    FormatToStream(stdout,inf ? MSG_UPDATE_INF : MSG_UPDATE,hwid,inf);

    if(!UpdateFn(NULL,hwid,inf,flags,&reboot)) {
        goto final;
    }

    FormatToStream(stdout,MSG_UPDATE_OK);

    failcode = reboot ? EXIT_REBOOT : EXIT_OK;

final:

    if(newdevMod) {
        FreeLibrary(newdevMod);
    }

    return failcode;
}