From 56c3f844dc69fca3e8a283c48c1f37a5b2c02e40 Mon Sep 17 00:00:00 2001
From: MarcoFalke <falke.marco@gmail.com>
Date: Mon, 23 Aug 2021 12:57:58 +0200
Subject: [PATCH] Merge bitcoin/bitcoin#22622: util: Check if specified config
 file cannot be opened

127b4608e9dbb8217c74c9332e82fcec8c326fa8 test: Check if specified config file cannot be opened (nthumann)
6bb54708e6457f21596793a7149dc6dfea1dc871 util: Check if specified config file cannot be opened (nthumann)

Pull request description:

  Fixes https://github.com/bitcoin/bitcoin/issues/22612.
  When running e.g. `./src/bitcoind -datadir=/tmp/bitcoin -regtest -conf=/tmp/bitcoin/regtest/bitcoin.conf` and the specified config cannot be opened (doesn't exist, permission denied, ...), the initialization silently uses the default config.

  As voidburn already noted:
  > I can't think of a situation in which a config file is specified explicitly (in the startup options, as per service unit linked above), but inaccessible, where the fail condition should be to keep booting using defaults instead.

  With this patch applied, the initialization will fail immediately, if the specified config file cannot be opened. If no config file is explicitly specified, the behavior is unchanged. This not only affects `bitcoind`, but also `bitcoin-cli` and `bitcoin-qt`.

  In the example below the datadir is accessible, but the config file is not due to insufficient permissions:
  ```
  $ ./src/bitcoind -datadir=/tmp/bitcoin -regtest --debug=1 -conf=/tmp/bitcoin/regtest/bitcoin.conf
  Error: Error reading configuration file: specified config file "/tmp/bitcoin/regtest/bitcoin.conf" could not be opened.
  ```

ACKs for top commit:
  0xB10C:
    ACK 127b4608e9dbb8217c74c9332e82fcec8c326fa8
  Zero-1729:
    tACK 127b4608e9dbb8217c74c9332e82fcec8c326fa8
  theStack:
    Tested ACK 127b4608e9dbb8217c74c9332e82fcec8c326fa8

Tree-SHA512: 4fe487921485426f1d1da8d256c388af517b984b639d776aec7b159b3e23b669824093d3bdd31139d9415ed5f5de405b3e6a51b110c8ab471f12b9c99ac67cc1
---
 src/util/system.cpp                    | 6 ++++++
 test/functional/feature_config_args.py | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/src/util/system.cpp b/src/util/system.cpp
index fdb2124382..639a378146 100644
--- a/src/util/system.cpp
+++ b/src/util/system.cpp
@@ -960,6 +960,12 @@ bool ArgsManager::ReadConfigFiles(std::string& error, bool ignore_invalid_keys)
     const std::string confPath = GetArg("-conf", BITCOIN_CONF_FILENAME);
     fsbridge::ifstream stream(GetConfigFile(confPath));
 
+    // not ok to have a config file specified that cannot be opened
+    if (IsArgSet("-conf") && !stream.good()) {
+        error = strprintf("specified config file \"%s\" could not be opened.", confPath);
+        return false;
+    }
+    // ok to not have a config file
     if (stream.good()) {
         if (!ReadConfigStream(stream, confPath, error, ignore_invalid_keys)) {
             return false;
diff --git a/test/functional/feature_config_args.py b/test/functional/feature_config_args.py
index 8447ecb496..d176576a4a 100755
--- a/test/functional/feature_config_args.py
+++ b/test/functional/feature_config_args.py
@@ -247,6 +247,10 @@ class ConfArgsTest(BitcoinTestFramework):
 
         self.nodes[0].assert_start_raises_init_error(['-conf=' + conf_file], 'Error: Error reading configuration file: specified data directory "' + new_data_dir + '" does not exist.')
 
+        # Check that an explicitly specified config file that cannot be opened fails
+        none_existent_conf_file = os.path.join(default_data_dir, "none_existent_dash.conf")
+        self.nodes[0].assert_start_raises_init_error(['-conf=' + none_existent_conf_file], 'Error: Error reading configuration file: specified config file "' + none_existent_conf_file + '" could not be opened.')
+
         # Create the directory and ensure the config file now works
         os.mkdir(new_data_dir)
         # Temporarily disabled, because this test would access the user's home dir (~/.bitcoin)