Pong, half of a cross-contract return value test
Context
Frontier and Homestead era deployment.
Key Facts
Description
The other half of a two contract experiment in reading non constant return values across a contract call. Pong holds a small signed value given to it at deployment, returns it transactionally, and records that a transactional retrieval was attempted. This deployment declares that flag before the creator address rather than after it, which packs the three variables into the storage slot in a different order and is the whole of the difference from the published source.
Source Verified
Heuristic Analysis
The following characteristics were detected through bytecode analysis and may not be accurate.
Frontier Era
The initial release of Ethereum. A bare-bones implementation for technical users.
Bytecode Overview
Verified Source Available
Source verified through compiler archaeology and exact bytecode matching.
View Verification ProofShow source code (Solidity)
// Submitted by EthereumHistory (ethereumhistory.com)
// Supposedly, contracts can get non-constant return values from other contracts. (Whereas you can't from web3/geth.)
// These two contracts are meant to test this. Like so:
// 1. Deploy Pong with a pongval.
// 2. Deploy Ping, giving it the address of Pong.
// 3. Call Ping.getPongvalRemote() using a sendTransaction...
// 4. ... which retreives the value of pongval from Pong.
// 5. If successful Ping.getPongval() should return the value from step 1.
// UPDATE: Pong doesn't need a copy of PongvalRetriever.
//contract PongvalRetriever {
// int8 pongval_tx_retrieval_attempted = 0;
// function getPongvalTransactional() public returns (int8){ // tells Ping how to interact with Pong.
// pongval_tx_retrieval_attempted = -1;
// return pongval_tx_retrieval_attempted;
// }
//}
contract Pong {
int8 pongval_tx_retrieval_attempted = 0;
address creator;
int8 pongval;
/*********
Step 1: Deploy Pong
*********/
function Pong(int8 _pongval)
{
creator = msg.sender;
pongval = _pongval;
}
/*********
Step 4. Transactionally return pongval, overriding PongvalRetriever
*********/
function getPongvalTransactional() public returns (int8)
{
pongval_tx_retrieval_attempted = 1;
return pongval;
}
// ----------------------------------------------------------------------------------------------------------------------------------------
/*********
pongval getter/setter, just in case.
*********/
function getPongvalConstant() public constant returns (int8)
{
return pongval;
}
function setPongval(int8 _pongval)
{
pongval = _pongval;
}
function getPongvalTxRetrievalAttempted() constant returns (int8)
{
return pongval_tx_retrieval_attempted;
}
/****
For double-checking this contract's address
****/
function getAddress() constant returns (address)
{
return this;
}
/**********
Standard kill() function to recover funds
**********/
function kill()
{
if (msg.sender == creator)
suicide(creator); // kills this contract and sends remaining funds back to creator
}
}
/*
var _pongval = -22;
var pongContract = web3.eth.contract([{
"constant": false,
"inputs": [{
"name": "_pongval",
"type": "int8"
}],
"name": "setPongval",
"outputs": [],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getAddress",
"outputs": [{
"name": "",
"type": "address"
}],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getPongvalConstant",
"outputs": [{
"name": "",
"type": "int8"
}],
"type": "function"
}, {
"constant": false,
"inputs": [],
"name": "kill",
"outputs": [],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getPongvalTxRetrievalAttempted",
"outputs": [{
"name": "",
"type": "int8"
}],
"type": "function"
}, {
"constant": false,
"inputs": [],
"name": "getPongvalTransactional",
"outputs": [{
"name": "",
"type": "int8"
}],
"type": "function"
}, {
"inputs": [{
"name": "_pongval",
"type": "int8"
}],
"type": "constructor"
}]);
var pong = pongContract.new(
_pongval, {
from: web3.eth.accounts[0],
data: '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',
gas: 1000000
},
function(e, contract) {
if (typeof contract.address != 'undefined') {
console.log(e, contract);
console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
}
});
// ****************************************************************** IMPORTANT!!!!!
var _pongAddress = web3.toBigNumber('0xbfb1316ab1b8e9a2a39c1c96ad325ea80c9e041f'); // ****************************************************************** IMPORTANT!!!!!
// ****************************************************************** IMPORTANT!!!!!
var pingContract = web3.eth.contract([{
"constant": false,
"inputs": [],
"name": "getAddress",
"outputs": [{
"name": "",
"type": "address"
}],
"type": "function"
}, {
"constant": false,
"inputs": [{
"name": "_pongAddress",
"type": "address"
}],
"name": "setPongAddress",
"outputs": [],
"type": "function"
}, {
"constant": false,
"inputs": [],
"name": "getPongvalRemote",
"outputs": [],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getPongvalConstant",
"outputs": [{
"name": "",
"type": "int8"
}],
"type": "function"
}, {
"constant": false,
"inputs": [],
"name": "kill",
"outputs": [],
"type": "function"
}, {
"constant": true,
"inputs": [],
"name": "getPongAddress",
"outputs": [{
"name": "",
"type": "address"
}],
"type": "function"
}, {
"constant": false,
"inputs": [],
"name": "getPongvalTransactional",
"outputs": [{
"name": "",
"type": "int8"
}],
"type": "function"
}, {
"inputs": [{
"name": "_pongAddress",
"type": "address"
}],
"type": "constructor"
}]);
var ping = pingContract.new(
_pongAddress, {
from: web3.eth.accounts[0],
data: '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',
gas: 1000000
},
function(e, contract) {
if (typeof contract.address != 'undefined') {
console.log(e, contract);
console.log('Contract mined! address: ' + contract.address + ' transactionHash: ' + contract.transactionHash);
}
});
> pong.getPongvalConstant(); // Was Pong.pongval initialized correctly?
- 22 // yes
> ping.getPongvalConstant(); // Does Ping know what pongval is yet?
- 1 // Nope. (This is correct at this point.)
> ping.getPongvalRemote.sendTransaction({
from: eth.coinbase,
gas: 1000000
}); // Tell Ping to get the pongval from Pong.
"0xc0ec18186cfccecc231af16c3caff6ee217c05833834dfaebe6ca119b51ca3a7" > ping.getPongvalConstant(); // Does Ping know what pongval is yet?
- 1 // Nope. Tx hasn't been mined yet.
> ping.getPongvalConstant(); // How about now?
- 22 // yep! Success!
*/External Links
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