Merge remote-tracking branch 'origin/pull/15935/head'

doc/files.md

@@ -50,14 +50,15 @@ Subdirectory       | File(s)               | Description
 `indexes/blockfilter/basic/`    | `fltrNNNNN.dat`<sup>[\[2\]](#note2)</sup> | Blockfilter index filters for the basic filtertype; *optional*, used if `-blockfilterindex=basic`
 `wallets/`         |                       | [Contains wallets](#multi-wallet-environment); can be specified by `-walletdir` option; if `wallets/` subdirectory does not exist, a wallet resides in the data directory
 `./`               | `banlist.dat`         | Stores the IPs/subnets of banned nodes
-`./`               | `bitcoin.conf`        | Contains [configuration settings](bitcoin-conf.md) for `bitcoind` or `bitcoin-qt`; can be specified by `-conf` option
+`./`               | `bitcoin.conf`        | User-defined [configuration settings](bitcoin-conf.md) for `bitcoind` or `bitcoin-qt`. File is read-only and must be created manually. Path can be specified by `-conf` option
 `./`               | `bitcoind.pid`        | Stores the process ID (PID) of `bitcoind` or `bitcoin-qt` while running; created at start and deleted on shutdown; can be specified by `-pid` option
 `./`               | `debug.log`           | Contains debug information and general logging generated by `bitcoind` or `bitcoin-qt`; can be specified by `-debuglogfile` option
 `./`               | `fee_estimates.dat`   | Stores statistics used to estimate minimum transaction fees and priorities required for confirmation
 `./`               | `guisettings.ini.bak` | Backup of former [GUI settings](#gui-settings) after `-resetguisettings` option is used
 `./`               | `mempool.dat`         | Dump of the mempool's transactions
 `./`               | `onion_private_key`   | Cached Tor hidden service private key for `-listenonion` option
 `./`               | `peers.dat`           | Peer IP address database (custom format)
+`./`               | `settings.json`        | Read-write settings set though GUI or RPC interfaces, augmenting manual settings from bitcoin.conf. File is created automatically if read-write setting storage is not disabled with `-nosettings` option. Path can be specified with `-settings` option
 `./`               | `.cookie`             | Session RPC authentication cookie; if used, created at start and deleted on shutdown; can be specified by `-rpccookiefile` option
 `./`               | `.lock`               | Data directory lock file
 

src/bitcoind.cpp

@@ -101,6 +101,11 @@ static bool AppInit(int argc, char* argv[])
             }
         }
 
+        if (!gArgs.ReadSettingsFile()) {
+            InitError(strprintf(Untranslated("Error reading settings file\n")));
+            return false;
+        }
+
         // -server defaults to true for bitcoind but not for the GUI so do this here
         gArgs.SoftSetBoolArg("-server", true);
         // Set this early so that parameter interactions go to console

src/init.cpp

@@ -395,7 +395,7 @@ void SetupServerArgs(NodeContext& node)
 #endif
     gArgs.AddArg("-blockreconstructionextratxn=<n>", strprintf("Extra transactions to keep in memory for compact block reconstructions (default: %u)", DEFAULT_BLOCK_RECONSTRUCTION_EXTRA_TXN), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-blocksonly", strprintf("Whether to reject transactions from network peers. Automatic broadcast and rebroadcast of any transactions from inbound peers is disabled, unless '-whitelistforcerelay' is '1', in which case whitelisted peers' transactions will be relayed. RPC transactions are not affected. (default: %u)", DEFAULT_BLOCKSONLY), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
-    gArgs.AddArg("-conf=<file>", strprintf("Specify configuration file. Relative paths will be prefixed by datadir location. (default: %s)", BITCOIN_CONF_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+    gArgs.AddArg("-conf=<file>", strprintf("Specify path to read-only configuration file. Relative paths will be prefixed by datadir location. (default: %s)", BITCOIN_CONF_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-datadir=<dir>", "Specify data directory", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-dbbatchsize", strprintf("Maximum database write batch size in bytes (default: %u)", nDefaultDbBatchSize), ArgsManager::ALLOW_ANY | ArgsManager::DEBUG_ONLY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-dbcache=<n>", strprintf("Maximum database cache size <n> MiB (%d to %d, default: %d). In addition, unused mempool memory is shared for this cache (see -maxmempool).", nMinDbCache, nMaxDbCache, nDefaultDbCache), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
@@ -416,6 +416,7 @@ void SetupServerArgs(NodeContext& node)
             "(default: 0 = disable pruning blocks, 1 = allow manual pruning via RPC, >=%u = automatically prune block files to stay under the specified target size in MiB)", MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-reindex", "Rebuild chain state and block index from the blk*.dat files on disk", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
     gArgs.AddArg("-reindex-chainstate", "Rebuild chain state from the currently indexed blocks. When in pruning mode or if blocks on disk might be corrupted, use full -reindex instead.", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
+    gArgs.AddArg("-settings=<file>", strprintf("Specify path to read-write settings file for storage of persistent settings. Can be disabled with -nosettings. Relative paths will be prefixed by datadir location. (default: %s)", BITCOIN_SETTINGS_FILENAME), ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #ifndef WIN32
     gArgs.AddArg("-sysperms", "Create new files with system default permissions, instead of umask 077 (only effective with disabled wallet functionality)", ArgsManager::ALLOW_ANY, OptionsCategory::OPTIONS);
 #else

src/interfaces/node.cpp

@@ -66,6 +66,7 @@ class NodeImpl : public Node
     bool softSetArg(const std::string& arg, const std::string& value) override { return gArgs.SoftSetArg(arg, value); }
     bool softSetBoolArg(const std::string& arg, bool value) override { return gArgs.SoftSetBoolArg(arg, value); }
     void selectParams(const std::string& network) override { SelectParams(network); }
+    bool readSettingsFile() override { return gArgs.ReadSettingsFile(); }
     uint64_t getAssumedBlockchainSize() override { return Params().AssumedBlockchainSize(); }
     uint64_t getAssumedChainStateSize() override { return Params().AssumedChainStateSize(); }
     std::string getNetwork() override { return Params().NetworkIDString(); }

src/interfaces/node.h

@@ -65,6 +65,11 @@ class Node
     //! Choose network parameters.
     virtual void selectParams(const std::string& network) = 0;
 
+    //! Load <datadir>/settings.json file with saved settings. This needs to be
+    //! called after selectParams() because the settings file is
+    //! network-specific.
+    virtual bool readSettingsFile() = 0;
+
     //! Get the (assumed) blockchain size.
     virtual uint64_t getAssumedBlockchainSize() = 0;
 

src/qt/bitcoin.cpp

@@ -528,6 +528,11 @@ int GuiMain(int argc, char* argv[])
     // Parse URIs on command line -- this can affect Params()
     PaymentServer::ipcParseCommandLine(*node, argc, argv);
 #endif
+    if (!node->readSettingsFile()) {
+        QMessageBox::critical(nullptr, QObject::tr(PACKAGE_NAME),
+                              QObject::tr("Error: Cannot read settings file."));
+        return EXIT_FAILURE;
+    }
 
     QScopedPointer<const NetworkStyle> networkStyle(NetworkStyle::instantiate(Params().NetworkIDString()));
     assert(!networkStyle.isNull());

src/util/settings.cpp

@@ -12,6 +12,7 @@ namespace {
 enum class Source {
    FORCED,
    COMMAND_LINE,
+   RW_SETTINGS,
    CONFIG_FILE_NETWORK_SECTION,
    CONFIG_FILE_DEFAULT_SECTION
 };
@@ -32,6 +33,10 @@ static void MergeSettings(const Settings& settings, const std::string& section,
     if (auto* values = FindKey(settings.command_line_options, name)) {
         fn(SettingsSpan(*values), Source::COMMAND_LINE);
     }
+    // Merge in the read-write settings
+    if (const SettingsValue* value = FindKey(settings.rw_settings, name)) {
+        fn(SettingsSpan(*value), Source::RW_SETTINGS);
+    }
     // Merge in the network-specific section of the config file
     if (!section.empty()) {
         if (auto* map = FindKey(settings.ro_config, section)) {

src/util/settings.h

@@ -24,19 +24,21 @@ namespace util {
 //!       https://github.com/bitcoin/bitcoin/pull/15934/files#r337691812)
 using SettingsValue = UniValue;
 
-//! Stored bitcoin settings. This struct combines settings from the command line
-//! and a read-only configuration file.
+//! Stored bitcoin settings. This struct combines settings from the command line,
+//! a read-only configuration file, and a read-write runtime settings file.
 struct Settings {
     //! Map of setting name to forced setting value.
     std::map<std::string, SettingsValue> forced_settings;
     //! Map of setting name to list of command line values.
     std::map<std::string, std::vector<SettingsValue>> command_line_options;
+    //! Map of setting name to read-write file setting value.
+    std::map<std::string, SettingsValue> rw_settings;
     //! Map of config section name and setting name to list of config file values.
     std::map<std::string, std::map<std::string, std::vector<SettingsValue>>> ro_config;
 };
 
 //! Get settings value from combined sources: forced settings, command line
-//! arguments and the read-only config file.
+//! arguments, runtime read-write settings, and the read-only config file.
 //!
 //! @param ignore_default_section_config - ignore values in the default section
 //!                                        of the config file (part before any

src/util/system.cpp

@@ -73,6 +73,7 @@
 const int64_t nStartupTime = GetTime();
 
 const char * const BITCOIN_CONF_FILENAME = "bitcoin.conf";
+const char * const BITCOIN_SETTINGS_FILENAME = "settings.json";
 
 ArgsManager gArgs;
 
@@ -372,6 +373,86 @@ bool ArgsManager::IsArgSet(const std::string& strArg) const
     return !GetSetting(strArg).isNull();
 }
 
+static bool GetSettingsPath(fs::path* filepath = nullptr, bool temp = false)
+{
+    if (gArgs.IsArgNegated("-settings")) return false;
+    if (filepath) {
+        std::string settings = gArgs.GetArg("-settings", BITCOIN_SETTINGS_FILENAME);
+        *filepath = fs::absolute(temp ? settings + ".tmp" : settings, GetDataDir(/* net_specific= */ true));
+    }
+    return true;
+}
+
+bool ArgsManager::EnableSettingsFile()
+{
+    return GetSettingsPath();
+}
+
+bool ArgsManager::ReadSettingsFile()
+{
+    fsbridge::ifstream file;
+    fs::path filepath;
+    if (!GetSettingsPath(&filepath, /* temp= */ false)) return true;
+    file.open(filepath);
+    if (!file.is_open()) return true; // Ok for file not to exist.
+
+    util::SettingsValue in;
+    if (!in.read(std::string{std::istreambuf_iterator<char>(file), std::istreambuf_iterator<char>()})) {
+        LogPrintf("Error: Unable to parse settings file %s\n", filepath.string());
+        return false;
+    }
+    if (file.fail()) {
+        LogPrintf("Error reading settings file %s\n", filepath.string());
+        return false;
+    }
+    file.close();
+
+    if (!in.isObject()) {
+        LogPrintf("Error: Settings file %s is not in expected key-value format.\n", filepath.string());
+        return false;
+    }
+
+    LOCK(cs_args);
+    m_settings.rw_settings.clear();
+    const std::vector<std::string>& keys = in.getKeys();
+    const std::vector<UniValue>& values = in.getValues();
+    for (size_t i = 0; i < keys.size(); ++i) {
+        m_settings.rw_settings.emplace(keys[i], values[i]);
+    }
+    return true;
+}
+
+bool ArgsManager::WriteSettingsFile() const
+{
+    fs::path filepath, filepath_tmp;
+    if (!GetSettingsPath(&filepath, /* temp= */ false) || !GetSettingsPath(&filepath_tmp, /* temp= */ true)) {
+        throw std::logic_error("Attempt to write settings file when dynamic settings are disabled.");
+    }
+
+    util::SettingsValue out(util::SettingsValue::VOBJ);
+    {
+        LOCK(cs_args);
+        for (const auto& value : m_settings.rw_settings) {
+            out.__pushKV(value.first, value.second);
+        }
+    }
+
+    fsbridge::ofstream file;
+    file.open(filepath_tmp);
+    if (file.fail()) {
+        LogPrintf("Error: Unable to open settings file %s for writing\n", filepath_tmp.string());
+        return false;
+    }
+    file << out.write(/* prettyIndent= */ 1, /* indentLevel= */ 4) << std::endl;
+    file.close();
+
+    if (!RenameOver(filepath_tmp, filepath)) {
+        LogPrintf("Error: Unable to rename settings file %s to %s\n", filepath_tmp.string(), filepath.string());
+        return false;
+    }
+    return true;
+}
+
 bool ArgsManager::IsArgNegated(const std::string& strArg) const
 {
     return GetSetting(strArg).isFalse();

src/util/system.h

@@ -41,6 +41,7 @@
 int64_t GetStartupTime();
 
 extern const char * const BITCOIN_CONF_FILENAME;
+extern const char * const BITCOIN_SETTINGS_FILENAME;
 
 void SetupEnvironment();
 bool SetupNetworking();
@@ -333,6 +334,34 @@ class ArgsManager
      */
     Optional<unsigned int> GetArgFlags(const std::string& name) const;
 
+    /**
+     * Return whether read-write settings are enabled. This is true unless
+     * bitcoin was configured with -nosettings to disable storing changed
+     * dynamic settings from the GUI or RPC methods.
+     */
+    bool EnableSettingsFile();
+
+    /**
+     * Load <datadir>/settings.json file with saved settings. This needs to be
+     * called after SelectParams() because the settings file is network-specific.
+     */
+    bool ReadSettingsFile();
+
+    /**
+     * Save <datadir>/settings.json file with persistent settings.
+     */
+    bool WriteSettingsFile() const;
+
+    /**
+     * Access settings with lock held.
+     */
+    template <typename Fn>
+    void LockSettings(Fn&& fn)
+    {
+        LOCK(cs_args);
+        fn(m_settings);
+    }
+
     /**
      * Log the config file options and the command line arguments,
      * useful for troubleshooting.