How to get eth v r s for removeLiquidityWithPermit

[vccomnet]

Hello, I'm developing an application. One of its functions is to call the removeLiquidityWithPermit interface of the decentralized exchange to remove liquidity. This interface can call the permit contract method to approve the LP, then DEX's router contract can
call transferFrom to tranfer the LPs asset。 I checked the relevant data, which is probably related to EIP712. I studied the test code of the wallet core. The code I wrote is as follows, but when calling, I returned execution reversed: UniswapV2: INVALID_ SIGNATURE error. Please help to see what the problem is? I think the parameters v, r and s are incorrect. Thank you.

char szEIP712[2048];

char* format = R"({
    "types": {
        "EIP712Domain": [
			{"name": "name", "type": "string"},
            {"name": "version", "type": "string"},
            {"name": "chainId", "type": "uint256"},
            {"name": "verifyingContract", "type": "address"}
        ],
        "Permit": [
            { "name": "owner", "type": "address" },
			{ "name": "spender", "type": "address" },
			{ "name": "value", "type": "uint256" },
			{ "name": "nonce", "type": "uint256" },
			{ "name": "deadline", "type": "uint256" }
        ]
    },
    "primaryType": "Permit",
    "domain": {
        "name": "Uniswap V2",
        "version": "1",
        "chainId": "%u",
        "verifyingContract": "%s"
    },
    "message": {
        "owner": "%s",
		"spender": "%s",
		"value": "%s",
		"nonce": "%u",
		"deadline": "%u"
    }
})";

char* verifyingContract = pTokenLP;
char* owner = pFrom;
char* spender = pToken;
char* value = Liquidity;
SP_UINT32 nonce = *pNonce;
SP_UINT32 deadline2 = ExpiresTime;

sprintf(szEIP712, format, ChainTable.udwChainID, verifyingContract, owner, spender, value, nonce, deadline2);

FILE* file = fopen("log.txt", "a");
fprintf(file, "%s\n", szEIP712);

auto hash = TW::Ethereum::ABI::ParamStruct::hashStructJson(szEIP712);

fprintf(file, "hash = %s\n", TW::hex(hash).c_str());

//if (TW::hex(hash) == "be609aee343fb3c4b28e1df9e632fca64fcfaede20f02e86244efddf30957bd2")
//{
//}

// sign the hash
TW::PrivateKey privateKeyCow = TW::PrivateKey(TW::Hash::keccak256(TW::data(pPrivKey)));
const auto rsv = TW::Ethereum::Signer::sign(privateKeyCow, hash, true, 100);

fprintf(file, "rsv.r = %s\n", TW::hex(TW::store(rsv.r)).c_str());
fprintf(file, "rsv.s = %s\n", TW::hex(TW::store(rsv.s)).c_str());
fprintf(file, "rsv.v = %s\n", TW::hex(TW::store(rsv.v)).c_str());

fclose(file);

auto& removeliquiditywithpermit = *input.mutable_transaction()->mutable_swap_removeliquiditywithpermit();
input.set_to_address(pToken);	/*router*/
removeliquiditywithpermit.set_tokena(pTokenA);
removeliquiditywithpermit.set_tokenb(pTokenB);
removeliquiditywithpermit.set_liquidity(liquidityData.data(), liquidityData.size());
removeliquiditywithpermit.set_amountamin(amountaminData.data(), amountaminData.size());
removeliquiditywithpermit.set_amountbmin(amountbminData.data(), amountbminData.size());
removeliquiditywithpermit.set_to(pTo);
removeliquiditywithpermit.set_approvemax(bApproveMax);
removeliquiditywithpermit.set_deadline(deadlineData.data(), deadlineData.size());

removeliquiditywithpermit.set_v(TW::hex(TW::store(rsv.v)).c_str());
removeliquiditywithpermit.set_r(TW::hex(TW::store(rsv.r)).c_str());
removeliquiditywithpermit.set_s(TW::hex(TW::store(rsv.s)).c_str());

auto tx = TW::Ethereum::Signer::build(input);
strcpy(pPayload, TW::hex(tx->payload).c_str());

// sign
TW::Ethereum::Proto::SigningOutput output;
ANY_SIGN(input, TWCoinTypeEthereum);
strcpy(pOut, TW::hex(output.encoded()).c_str());