Merge #15687: test: tool wallet test coverage for unexpected writes to wallet

7195fa792fcc19e9c064c4e38814c3b46a210b34 test: Tool wallet test coverage for unexpected writes to wallet (Jon Atack)
3bf2b3a37bbd550491d124b77fd7c1b2a7969f66 test: Split tool_wallet.py test into subtests (Jon Atack)
1eb13f09a9d8c2c7dc69f4cdf1b1ccf632543aa0 test: Add log messages to test/functional/tool_wallet.py (Jon Atack)

Pull request description:

  This pull request adds test coverage in `test/functional/tool_wallet.py` to reproduce unexpected writes to the wallet as described in https://github.com/bitcoin/bitcoin/issues/15608 and serve as a benchmark for fixing the issue:

  - Wallet tool `info` unexpectedly writes to the wallet file if the wallet file permissions are read/write.

  - Wallet tool `info` raises with "Error loading . Is wallet being used by another process?" if the wallet file permissions are read-only.

  Goals:

  1. Reproduce the reported issue, define the current unexpected behavior, and add test coverage to guide a future fix. Add debug-level logging for sanity checking and commented-out assertions to be uncommented when fixing the issue. Add the same coverage to the wallet tool create test and the getwalletinfo test as regression tests while fixing the issue.

  2. Add info log messages as there are currently none in the test file.

  3. Split the tests out to separate functions as per review feedback.

  Thanks to Marco Falke for pointing me in the right direction.

ACKs for top commit:
  laanwj:
    code review ACK 7195fa792fcc19e9c064c4e38814c3b46a210b34

Tree-SHA512: 16a41cce989c8f819cf5b02c6cf8ea84653ede2738fb402f6c36cf4dc075b424dff3e2c73a1cfa1ec9c75f614675baecc71e588845a2596db06ba0957db2df7b

test/functional/tool_wallet.py

@@ -1,14 +1,20 @@
 #!/usr/bin/env python3
-# Copyright (c) 2018 The Bitcoin Core developers
+# Copyright (c) 2018-2019 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 dash-wallet."""
+
+import hashlib
+import os
+import stat
 import subprocess
 import textwrap
 
 from test_framework.test_framework import BitcoinTestFramework
 from test_framework.util import assert_equal
 
+BUFFER_SIZE = 16 * 1024
+
 class ToolWalletTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
@@ -32,23 +38,54 @@ class ToolWalletTest(BitcoinTestFramework):
     def assert_tool_output(self, output, *args):
         p = self.dash_wallet_process(*args)
         stdout, stderr = p.communicate()
-        assert_equal(p.poll(), 0)
         assert_equal(stderr, '')
         assert_equal(stdout, output)
+        assert_equal(p.poll(), 0)
 
-    def run_test(self):
+    def wallet_shasum(self):
+        h = hashlib.sha1()
+        mv = memoryview(bytearray(BUFFER_SIZE))
+        with open(self.wallet_path, 'rb', buffering=0) as f:
+            for n in iter(lambda : f.readinto(mv), 0):
+                h.update(mv[:n])
+        return h.hexdigest()
 
+    def wallet_timestamp(self):
+        return os.path.getmtime(self.wallet_path)
+
+    def wallet_permissions(self):
+        return oct(os.lstat(self.wallet_path).st_mode)[-3:]
+
+    def log_wallet_timestamp_comparison(self, old, new):
+        result = 'unchanged' if new == old else 'increased!'
+        self.log.debug('Wallet file timestamp {}'.format(result))
+
+    def test_invalid_tool_commands_and_args(self):
+        self.log.info('Testing that various invalid commands raise with specific error messages')
         self.assert_raises_tool_error('Invalid command: foo', 'foo')
-        # `dash-wallet help` is an error. Use `dash-wallet -help`
+        # `dash-wallet help` raises an error. Use `dash-wallet -help`.
         self.assert_raises_tool_error('Invalid command: help', 'help')
         self.assert_raises_tool_error('Error: two methods provided (info and create). Only one method should be provided.', 'info', 'create')
         self.assert_raises_tool_error('Error parsing command line arguments: Invalid parameter -foo', '-foo')
         self.assert_raises_tool_error('Error loading wallet.dat. Is wallet being used by other process?', '-wallet=wallet.dat', 'info')
         self.assert_raises_tool_error('Error: no wallet file at nonexistent.dat', '-wallet=nonexistent.dat', 'info')
 
-        # stop the node to close the wallet to call info command
+    def test_tool_wallet_info(self):
+        # Stop the node to close the wallet to call the info command.
         self.stop_node(0)
-
+        self.log.info('Calling wallet tool info, testing output')
+        #
+        # TODO: Wallet tool info should work with wallet file permissions set to
+        # read-only without raising:
+        # "Error loading wallet.dat. Is wallet being used by another process?"
+        # The following lines should be uncommented and the tests still succeed:
+        #
+        # self.log.debug('Setting wallet file permissions to 400 (read-only)')
+        # os.chmod(self.wallet_path, stat.S_IRUSR)
+        # assert(self.wallet_permissions() in ['400', '666']) # Sanity check. 666 because Appveyor.
+        # shasum_before = self.wallet_shasum()
+        timestamp_before = self.wallet_timestamp()
+        self.log.debug('Wallet file timestamp before calling info: {}'.format(timestamp_before))
         out = textwrap.dedent('''\
             Wallet info
             ===========
@@ -74,12 +111,35 @@ class ToolWalletTest(BitcoinTestFramework):
             Address Book: 0
         ''')
         self.assert_tool_output(out, '-wallet=wallet.dat', 'info')
+        timestamp_after = self.wallet_timestamp()
+        self.log.debug('Wallet file timestamp after calling info: {}'.format(timestamp_after))
+        self.log_wallet_timestamp_comparison(timestamp_before, timestamp_after)
+        self.log.debug('Setting wallet file permissions back to 600 (read/write)')
+        os.chmod(self.wallet_path, stat.S_IRUSR | stat.S_IWUSR)
+        assert(self.wallet_permissions() in ['600', '666']) # Sanity check. 666 because Appveyor.
+        #
+        # TODO: Wallet tool info should not write to the wallet file.
+        # The following lines should be uncommented and the tests still succeed:
+        #
+        # assert_equal(timestamp_before, timestamp_after)
+        # shasum_after = self.wallet_shasum()
+        # assert_equal(shasum_before, shasum_after)
+        # self.log.debug('Wallet file shasum unchanged\n')
 
-        # mutate the wallet to check the info command output changes accordingly
+    def test_tool_wallet_info_after_transaction(self):
+        """
+        Mutate the wallet with a transaction to verify that the info command
+        output changes accordingly.
+        """
         self.start_node(0)
+        self.log.info('Generating transaction to mutate wallet')
         self.nodes[0].generate(1)
         self.stop_node(0)
 
+        self.log.info('Calling wallet tool info after generating a transaction, testing output')
+        shasum_before = self.wallet_shasum()
+        timestamp_before = self.wallet_timestamp()
+        self.log.debug('Wallet file timestamp before calling info: {}'.format(timestamp_before))
         out = textwrap.dedent('''\
             Wallet info
             ===========
@@ -90,7 +150,22 @@ class ToolWalletTest(BitcoinTestFramework):
             Address Book: 0
         ''')
         self.assert_tool_output(out, '-wallet=wallet.dat', 'info')
+        shasum_after = self.wallet_shasum()
+        timestamp_after = self.wallet_timestamp()
+        self.log.debug('Wallet file timestamp after calling info: {}'.format(timestamp_after))
+        self.log_wallet_timestamp_comparison(timestamp_before, timestamp_after)
+        #
+        # TODO: Wallet tool info should not write to the wallet file.
+        # This assertion should be uncommented and succeed:
+        # assert_equal(timestamp_before, timestamp_after)
+        assert_equal(shasum_before, shasum_after)
+        self.log.debug('Wallet file shasum unchanged\n')
 
+    def test_tool_wallet_create_on_existing_wallet(self):
+        self.log.info('Calling wallet tool create on an existing wallet, testing output')
+        shasum_before = self.wallet_shasum()
+        timestamp_before = self.wallet_timestamp()
+        self.log.debug('Wallet file timestamp before calling create: {}'.format(timestamp_before))
         out = textwrap.dedent('''\
             Topping up keypool...
             Wallet info
@@ -102,13 +177,46 @@ class ToolWalletTest(BitcoinTestFramework):
             Address Book: 0
         ''')
         self.assert_tool_output(out, '-wallet=foo', 'create')
+        shasum_after = self.wallet_shasum()
+        timestamp_after = self.wallet_timestamp()
+        self.log.debug('Wallet file timestamp after calling create: {}'.format(timestamp_after))
+        self.log_wallet_timestamp_comparison(timestamp_before, timestamp_after)
+        assert_equal(timestamp_before, timestamp_after)
+        assert_equal(shasum_before, shasum_after)
+        self.log.debug('Wallet file shasum unchanged\n')
 
+    def test_getwalletinfo_on_different_wallet(self):
+        self.log.info('Starting node with arg -wallet=foo')
         self.start_node(0, ['-wallet=foo'])
+
+        self.log.info('Calling getwalletinfo on a different wallet ("foo"), testing output')
+        shasum_before = self.wallet_shasum()
+        timestamp_before = self.wallet_timestamp()
+        self.log.debug('Wallet file timestamp before calling getwalletinfo: {}'.format(timestamp_before))
         out = self.nodes[0].getwalletinfo()
         self.stop_node(0)
 
+        shasum_after = self.wallet_shasum()
+        timestamp_after = self.wallet_timestamp()
+        self.log.debug('Wallet file timestamp after calling getwalletinfo: {}'.format(timestamp_after))
+
         assert_equal(0, out['txcount'])
         assert_equal(1000, out['keypoolsize'])
 
+        self.log_wallet_timestamp_comparison(timestamp_before, timestamp_after)
+        assert_equal(timestamp_before, timestamp_after)
+        assert_equal(shasum_after, shasum_before)
+        self.log.debug('Wallet file shasum unchanged\n')
+
+    def run_test(self):
+        self.wallet_path = os.path.join(self.nodes[0].datadir, 'regtest', 'wallets', 'wallet.dat')
+        self.test_invalid_tool_commands_and_args()
+        # Warning: The following tests are order-dependent.
+        self.test_tool_wallet_info()
+        self.test_tool_wallet_info_after_transaction()
+        self.test_tool_wallet_create_on_existing_wallet()
+        self.test_getwalletinfo_on_different_wallet()
+
+
 if __name__ == '__main__':
     ToolWalletTest().main()