// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// ReleaseOracle is an Ethereum contract to store the current and previous
// versions of the go-ethereum implementation. Its goal is to allow Geth to
// check for new releases automatically without the need to consult a central
// repository.
//
// The contract takes a vote based approach on both assigning authorised signers
// as well as signing off on new Geth releases.
//
// Note, when a signer is demoted, the currently pending release is auto-nuked.
// The reason is to prevent suprises where a demotion actually tilts the votes
// in favor of one voter party and pushing out a new release as a consequence of
// a simple demotion.
contract ReleaseOracle {
// Votes is an internal data structure to count votes on a specific proposal
struct Votes {
address[] pass; // List of signers voting to pass a proposal
address[] fail; // List of signers voting to fail a proposal
}
// Version is the version details of a particular Geth release
struct Version {
uint32 major; // Major version component of the release
uint32 minor; // Minor version component of the release
uint32 patch; // Patch version component of the release
bytes20 commit; // Git SHA1 commit hash of the release
uint64 time; // Timestamp of the release approval
Votes votes; // Votes that passed this release
}
// Oracle authorization details
mapping(address => bool) authorised; // Set of accounts allowed to vote on updating the contract
address[] voters; // List of addresses currently accepted as signers
// Various proposals being voted on
mapping(address => Votes) authProps; // Currently running user authorization proposals
address[] authPend; // List of addresses being voted on (map indexes)
Version verProp; // Currently proposed release being voted on
Version[] releases; // All the positively voted releases
// isSigner is a modifier to authorize contract transactions.
modifier isSigner() {
if (authorised[msg.sender]) {
_
}
}
// Constructor to assign the initial set of signers.
function ReleaseOracle(address[] signers) {
// If no signers were specified, assign the creator as the sole signer
if (signers.length == 0) {
authorised[msg.sender] = true;
voters.push(msg.sender);
return;
}
// Otherwise assign the individual signers one by one
for (uint i = 0; i < signers.length; i++) {
authorised[signers[i]] = true;
voters.push(signers[i]);
}
}
// signers is an accessor method to retrieve all te signers (public accessor
// generates an indexed one, not a retrieve-all version).
function signers() constant returns(address[]) {
return voters;
}
// authProposals retrieves the list of addresses that authorization proposals
// are currently being voted on.
function authProposals() constant returns(address[]) {
return authPend;
}
// authVotes retrieves the current authorization votes for a particular user
// to promote him into the list of signers, or demote him from there.
function authVotes(address user) constant returns(address[] promote, address[] demote) {
return (authProps[user].pass, authProps[user].fail);
}
// currentVersion retrieves the semantic version, commit hash and release time
// of the currently votec active release.
function currentVersion() constant returns (uint32 major, uint32 minor, uint32 patch, bytes20 commit, uint time) {
if (releases.length == 0) {
return (0, 0, 0, 0, 0);
}
var release = releases[releases.length - 1];
return (release.major, release.minor, release.patch, release.commit, release.time);
}
// proposedVersion retrieves the semantic version, commit hash and the current
// votes for the next proposed release.
function proposedVersion() constant returns (uint32 major, uint32 minor, uint32 patch, bytes20 commit, address[] pass, address[] fail) {
return (verProp.major, verProp.minor, verProp.patch, verProp.commit, verProp.votes.pass, verProp.votes.fail);
}
// promote pitches in on a voting campaign to promote a new user to a signer
// position.
function promote(address user) {
updateSigner(user, true);
}
// demote pitches in on a voting campaign to demote an authorised user from
// its signer position.
function demote(address user) {
updateSigner(user, false);
}
// release votes for a particular version to be included as the next release.
function release(uint32 major, uint32 minor, uint32 patch, bytes20 commit) {
updateRelease(major, minor, patch, commit, true);
}
// nuke votes for the currently proposed version to not be included as the next
// release. Nuking doesn't require a specific version number for simplicity.
function nuke() {
updateRelease(0, 0, 0, 0, false);
}
// updateSigner marks a vote for changing the status of an Ethereum user, either
// for or against the user being an authorised signer.
function updateSigner(address user, bool authorize) internal isSigner {
// Gather the current votes and ensure we don't double vote
Votes votes = authProps[user];
for (uint i = 0; i < votes.pass.length; i++) {
if (votes.pass[i] == msg.sender) {
return;
}
}
for (i = 0; i < votes.fail.length; i++) {
if (votes.fail[i] == msg.sender) {
return;
}
}
// If no authorization proposal is open, add the user to the index for later lookups
if (votes.pass.length == 0 && votes.fail.length == 0) {
authPend.push(user);
}
// Cast the vote and return if the proposal cannot be resolved yet
if (authorize) {
votes.pass.push(msg.sender);
if (votes.pass.length <= voters.length / 2) {
return;
}
} else {
votes.fail.push(msg.sender);
if (votes.fail.length <= voters.length / 2) {
return;
}
}
// Proposal resolved in our favor, execute whatever we voted on
if (authorize && !authorised[user]) {
authorised[user] = true;
voters.push(user);
} else if (!authorize && authorised[user]) {
authorised[user] = false;
for (i = 0; i < voters.length; i++) {
if (voters[i] == user) {
voters[i] = voters[voters.length - 1];
voters.length--;
delete verProp; // Nuke any version proposal (no surprise releases!)
break;
}
}
}
// Finally delete the resolved proposal, index and garbage collect
delete authProps[user];
for (i = 0; i < authPend.length; i++) {
if (authPend[i] == user) {
authPend[i] = authPend[authPend.length - 1];
authPend.length--;
break;
}
}
}
// updateRelease votes for a particular version to be included as the next release,
// or for the currently proposed release to be nuked out.
function updateRelease(uint32 major, uint32 minor, uint32 patch, bytes20 commit, bool release) internal isSigner {
// Skip nuke votes if no proposal is pending
if (!release && verProp.votes.pass.length == 0) {
return;
}
// Mark a new release if no proposal is pending
if (verProp.votes.pass.length == 0) {
verProp.major = major;
verProp.minor = minor;
verProp.patch = patch;
verProp.commit = commit;
}
// Make sure positive votes match the current proposal
if (release && (verProp.major != major || verProp.minor != minor || verProp.patch != patch || verProp.commit != commit)) {
return;
}
// Gather the current votes and ensure we don't double vote
Votes votes = verProp.votes;
for (uint i = 0; i < votes.pass.length; i++) {
if (votes.pass[i] == msg.sender) {
return;
}
}
for (i = 0; i < votes.fail.length; i++) {
if (votes.fail[i] == msg.sender) {
return;
}
}
// Cast the vote and return if the proposal cannot be resolved yet
if (release) {
votes.pass.push(msg.sender);
if (votes.pass.length <= voters.length / 2) {
return;
}
} else {
votes.fail.push(msg.sender);
if (votes.fail.length <= voters.length / 2) {
return;
}
}
// Proposal resolved in our favor, execute whatever we voted on
if (release) {
verProp.time = uint64(now);
releases.push(verProp);
delete verProp;
} else {
delete verProp;
}
}
}
