test: add functional test for XORed block/undo files (-blocksxor)

test/functional/feature_blocksxor.py

@@ -0,0 +1,65 @@
+#!/usr/bin/env python3
+# Copyright (c) 2024 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test support for XORed block data and undo files (`-blocksxor` option)."""
+import os
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.test_node import ErrorMatch
+from test_framework.util import (
+    assert_equal,
+    assert_greater_than,
+    read_xor_key,
+    util_xor,
+)
+from test_framework.wallet import MiniWallet
+
+
+class BlocksXORTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.num_nodes = 1
+        self.extra_args = [[
+            '-blocksxor=1',
+            '-fastprune=1',             # use smaller block files
+            '-datacarriersize=100000',  # needed to pad transaction with MiniWallet
+        ]]
+
+    def run_test(self):
+        self.log.info("Mine some blocks, to create multiple blk*.dat/rev*.dat files")
+        node = self.nodes[0]
+        wallet = MiniWallet(node)
+        for _ in range(5):
+            wallet.send_self_transfer(from_node=node, target_weight=80000)
+            self.generate(wallet, 1)
+
+        block_files = list(node.blocks_path.glob('blk[0-9][0-9][0-9][0-9][0-9].dat'))
+        undo_files  = list(node.blocks_path.glob('rev[0-9][0-9][0-9][0-9][0-9].dat'))
+        assert_equal(len(block_files), len(undo_files))
+        assert_greater_than(len(block_files), 1)  # we want at least one full block file
+
+        self.log.info("Shut down node and un-XOR block/undo files manually")
+        self.stop_node(0)
+        xor_key = read_xor_key(node=node)
+        for data_file in sorted(block_files + undo_files):
+            self.log.debug(f"Rewriting file {data_file}...")
+            with open(data_file, 'rb+') as f:
+                xored_data = f.read()
+                f.seek(0)
+                f.write(util_xor(xored_data, xor_key, offset=0))
+
+        self.log.info("Check that restarting with 'blocksxor=0' fails if XOR key is present")
+        node.assert_start_raises_init_error(['-blocksxor=0'],
+            'The blocksdir XOR-key can not be disabled when a random key was already stored!',
+            match=ErrorMatch.PARTIAL_REGEX)
+
+        self.log.info("Delete XOR key, restart node with '-blocksxor=0', check blk*.dat/rev*.dat file integrity")
+        os.remove(node.blocks_path / 'xor.dat')
+        self.start_node(0, extra_args=['-blocksxor=0'])
+        # checklevel=2 -> verify block validity + undo data
+        # nblocks=0    -> verify all blocks
+        node.verifychain(checklevel=2, nblocks=0)
+
+
+if __name__ == '__main__':
+    BlocksXORTest(__file__).main()

test/functional/test_runner.py

@@ -284,6 +284,7 @@
     'mempool_package_limits.py',
     'mempool_package_rbf.py',
     'feature_versionbits_warning.py',
+    'feature_blocksxor.py',
     'rpc_preciousblock.py',
     'wallet_importprunedfunds.py --legacy-wallet',
     'wallet_importprunedfunds.py --descriptors',