Wallet Passphrase Change Function

[khangmartin]

In the Bitcoin source code from github, RPCwallet.cpp is my question is centered. The questions are as follows:

     1. Is this the only function where the wallet passphrase can be changed? Meaning, does the gui for askpassphrase point to this same location?
     2. Do anyone know the exact variable which is referenced for the oldpassphrase comparison?

I have attached the function below for reference. The reason for the question, I want to complete a stand-a-lone work around for when I forget or type my password in incorrectly for my current wallet. Thanks for all your help in advance. Please leave address for tip receipt for all answers that help me on this task.

static UniValue walletpassphrasechange(const JSONRPCRequest& request)
{
    std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();

    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }

            RPCHelpMan{"walletpassphrasechange",
                "\nChanges the wallet passphrase from 'oldpassphrase' to 'newpassphrase'.\n",
                {
                    {"oldpassphrase", RPCArg::Type::STR, RPCArg::Optional::NO, "The current passphrase"},
                    {"newpassphrase", RPCArg::Type::STR, RPCArg::Optional::NO, "The new passphrase"},
                },
                RPCResults{},
                RPCExamples{
                    HelpExampleCli("walletpassphrasechange", "\"old one\" \"new one\"")
            + HelpExampleRpc("walletpassphrasechange", "\"old one\", \"new one\"")
                },
            }.Check(request);

    auto locked_chain = pwallet->chain().lock();
    LOCK(pwallet->cs_wallet);

    if (!pwallet->IsCrypted()) {
        throw JSONRPCError(RPC_WALLET_WRONG_ENC_STATE, "Error: running with an unencrypted wallet, but walletpassphrasechange was called.");
    }

    // TODO: get rid of these .c_str() calls by implementing SecureString::operator=(std::string)
    // Alternately, find a way to make request.params[0] mlock()'d to begin with.
    SecureString strOldWalletPass;
    strOldWalletPass.reserve(100);
    strOldWalletPass = request.params[0].get_str().c_str();

    SecureString strNewWalletPass;
    strNewWalletPass.reserve(100);
    strNewWalletPass = request.params[1].get_str().c_str();

    if (strOldWalletPass.empty() || strNewWalletPass.empty()) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "passphrase can not be empty");
    }

    if (!pwallet->ChangeWalletPassphrase(strOldWalletPass, strNewWalletPass)) {
        throw JSONRPCError(RPC_WALLET_PASSPHRASE_INCORRECT, "Error: The wallet passphrase entered was incorrect.");
    }

    return NullUniValue;
}