Create and initialize SystemSignerRegistry keeping track of signers

Author: ranchalp

scripts/foundry/InitializeL1ScrollOwner.s.sol

@@ -21,6 +21,9 @@ import {ScrollChain} from "../../src/L1/rollup/ScrollChain.sol";
 import {ScrollOwner} from "../../src/misc/ScrollOwner.sol";
 import {Whitelist} from "../../src/L2/predeploys/Whitelist.sol";
 
+import {SystemSignerRegistry} from "../../src/L1/system-contract/SystemSignerRegistry.sol";
+
+
 // solhint-disable max-states-count
 // solhint-disable state-visibility
 // solhint-disable var-name-mixedcase
@@ -81,7 +84,8 @@ contract InitializeL1ScrollOwner is Script {
         configL1GatewayRouter();
         configL1CustomERC20Gateway();
         configL1ERC721Gateway();
-        configL1ERC1155Gateway();
+        configL1ERC1155Gateway();        
+        configSystemContract();
 
         configL1USDCGateway();
         configEnforcedTxGateway();
@@ -272,4 +276,21 @@ contract InitializeL1ScrollOwner is Script {
         owner.updateAccess(L1_ENFORCED_TX_GATEWAY_PROXY_ADDR, _selectors, SCROLL_MULTISIG_NO_DELAY_ROLE, true);
         owner.updateAccess(L1_ENFORCED_TX_GATEWAY_PROXY_ADDR, _selectors, EMERGENCY_MULTISIG_NO_DELAY_ROLE, true);
     }
+
+    function configSystemContract() internal {
+        // If we already have deployed it, just do:
+        SystemSignerRegistry sys = SystemSignerRegistry(SYSTEM_CONTRACT_ADDR);
+
+        // sys has a normal constructor that set the "owner" to `ScrollOwner`.
+        // Now we want to let the Security Council call `addSigner(...)` with no delay.
+        bytes4[] memory selectors = new bytes4[](1);
+        selectors[0] = sys.addSigner.selector;
+
+        owner.updateAccess(
+            SYSTEM_CONTRACT_ADDR,        // the system contract
+            selectors,                   // array of function selectors (onlyOwner)
+            SECURITY_COUNCIL_NO_DELAY_ROLE,
+            true
+        );
+    }
 }

src/L1/L1ScrollMessenger.sol

@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: MIT
-
 pragma solidity =0.8.24;
 
 import {IScrollChain} from "./rollup/IScrollChain.sol";
@@ -10,6 +9,7 @@ import {IScrollMessenger} from "../libraries/IScrollMessenger.sol";
 import {ScrollMessengerBase} from "../libraries/ScrollMessengerBase.sol";
 import {WithdrawTrieVerifier} from "../libraries/verifier/WithdrawTrieVerifier.sol";
 
+
 import {IMessageDropCallback} from "../libraries/callbacks/IMessageDropCallback.sol";
 
 // solhint-disable avoid-low-level-calls

src/L1/system-contract/SystemSignerRegistry.sol

@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: MIT
+pragma solidity =0.8.24;
+
+import "@openzeppelin/contracts/access/Ownable.sol";
+
+/**
+ * @dev Example "SystemSignerRegistry" storing `(startBlock, signer)` pairs.
+ *      The getSigners() function returns parallel arrays for block numbers and addresses,
+ *      
+ */
+contract SystemSignerRegistry is Ownable {
+    struct Signer {
+        uint64 startBlock;
+        address signer;
+    }
+
+    Signer[] private signers;
+
+    constructor(address _owner) {
+        _transferOwnership(_owner);
+    }
+
+    /**
+     * @dev Add a (startBlock, signer) pair. Only the owner can do this.
+     */
+    function addSigner(uint64 _startBlock, address _signer) external onlyOwner {
+        require(_signer != address(0), "Zero address not allowed");
+        signers.push(Transition({startBlock: _startBlock, signer: _signer}));
+    }
+
+    /**
+     * @dev Remove a signer by matching both startBlock & signer, or just signer (you choose).
+     *      
+     */
+    function removeSigner(uint64 _startBlock, address _signer) external onlyOwner {
+        uint256 length = signers.length;
+        for (uint256 i = 0; i < length; i++) {
+            // If you only want to match signer, ignore _startBlock
+            if (signers[i].startBlock == _startBlock && signers[i].signer == _signer) {
+                if (i < length - 1) {
+                    signers[i] = signers[length - 1];
+                }
+                signers.pop();
+                return;
+            }
+        }
+        revert("Transition not found");
+    }
+
+    /**
+     * @dev Return two parallel arrays: blockNumbers and signers.
+     *    
+     */
+    function getSigners() external view returns (uint64[] memory, address[] memory) {
+        uint256 len = transitions.length;
+        uint64[] memory blocks = new uint64[](len);
+        address[] memory addrs = new address[](len);
+
+        for (uint256 i = 0; i < len; i++) {
+            blocks[i] = signers[i].startBlock;
+            addrs[i] = signers[i].signer;
+        }
+        return (blocks, addrs);
+    }
+}