text: // Copyright (c) 2009-2010 Satoshi Nakamoto
  // Copyright (c) 2009-2019 The Bitcoin Core developers
  // Distributed under the MIT software license, see the accompanying
  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
  
  #include <util/system.h>
  
  #include <chainparamsbase.h>
  #include <sync.h>
  #include <util/strencodings.h>
  #include <util/string.h>
  #include <util/translation.h>
  
  #include <univalue.h>
  
  #include <boost/thread.hpp>
  
  #include <memory>
  #include <thread>
  #include <typeinfo>
  
  #if (defined(__FreeBSD__) || defined(__OpenBSD__) || defined(__DragonFly__))
  #include <pthread.h>
  #include <pthread_np.h>
  #endif
  
  #ifndef WIN32
  // for posix_fallocate, in config/CMakeLists.txt we check if it is present after
  // this
  #ifdef __linux__
  
  #ifdef _POSIX_C_SOURCE
  #undef _POSIX_C_SOURCE
  #endif
  
  #define _POSIX_C_SOURCE 200112L
  
  #endif // __linux__
  
  #include <algorithm>
  #include <fcntl.h>
  #include <sched.h>
  #include <sys/resource.h>
  #include <sys/stat.h>
  
  #else
  
  #ifdef _MSC_VER
  #pragma warning(disable : 4786)
  #pragma warning(disable : 4804)
  #pragma warning(disable : 4805)
  #pragma warning(disable : 4717)
  #endif
  
  #ifndef NOMINMAX
  #define NOMINMAX
  #endif
  #include <codecvt>
  
  #include <io.h> /* for _commit */
  #include <shellapi.h>
  #include <shlobj.h>
  #endif
  
  #ifdef HAVE_MALLOPT_ARENA_MAX
  #include <malloc.h>
  #endif
  
  #include <boost/algorithm/string/replace.hpp>
  
  // Application startup time (used for uptime calculation)
  const int64_t nStartupTime = GetTime();
  
  const char *const BITCOIN_CONF_FILENAME = "bitcoin.conf";
  const char *const BITCOIN_SETTINGS_FILENAME = "settings.json";
  
  ArgsManager gArgs;
  
  /** Mutex to protect dir_locks. */
  static Mutex cs_dir_locks;
  /**
   * A map that contains all the currently held directory locks. After successful
   * locking, these will be held here until the global destructor cleans them up
   * and thus automatically unlocks them, or ReleaseDirectoryLocks is called.
   */
  static std::map<std::string, std::unique_ptr<fsbridge::FileLock>>
      dir_locks GUARDED_BY(cs_dir_locks);
  
  bool LockDirectory(const fs::path &directory, const std::string lockfile_name,
                     bool probe_only) {
      LOCK(cs_dir_locks);
      fs::path pathLockFile = directory / lockfile_name;
  
      // If a lock for this directory already exists in the map, don't try to
      // re-lock it
      if (dir_locks.count(pathLockFile.string())) {
          return true;
      }
  
      // Create empty lock file if it doesn't exist.
      FILE *file = fsbridge::fopen(pathLockFile, "a");
      if (file) {
          fclose(file);
      }
      auto lock = std::make_unique<fsbridge::FileLock>(pathLockFile);
      if (!lock->TryLock()) {
          return error("Error while attempting to lock directory %s: %s",
                       directory.string(), lock->GetReason());
      }
      if (!probe_only) {
          // Lock successful and we're not just probing, put it into the map
          dir_locks.emplace(pathLockFile.string(), std::move(lock));
      }
      return true;
  }
  
  void UnlockDirectory(const fs::path &directory,
                       const std::string &lockfile_name) {
      LOCK(cs_dir_locks);
      dir_locks.erase((directory / lockfile_name).string());
  }
  
  void ReleaseDirectoryLocks() {
      LOCK(cs_dir_locks);
      dir_locks.clear();
  }
  
  bool DirIsWritable(const fs::path &directory) {
      fs::path tmpFile = directory / fs::unique_path();
  
      FILE *file = fsbridge::fopen(tmpFile, "a");
      if (!file) {
          return false;
      }
  
      fclose(file);
      remove(tmpFile);
  
      return true;
  }
  
  bool CheckDiskSpace(const fs::path &dir, uint64_t additional_bytes) {
      // 50 MiB
      constexpr uint64_t min_disk_space = 52428800;
  
      uint64_t free_bytes_available = fs::space(dir).available;
      return free_bytes_available >= min_disk_space + additional_bytes;
  }
  
  std::streampos GetFileSize(const char *path, std::streamsize max) {
      std::ifstream file(path, std::ios::binary);
      file.ignore(max);
      return file.gcount();
  }
  
  /**
   * Interpret a string argument as a boolean.
   *
   * The definition of atoi() requires that non-numeric string values like "foo",
   * return 0. This means that if a user unintentionally supplies a non-integer
   * argument here, the return value is always false. This means that -foo=false
   * does what the user probably expects, but -foo=true is well defined but does
   * not do what they probably expected.
   *
   * The return value of atoi() is undefined when given input not representable as
   * an int. On most systems this means string value between "-2147483648" and
   * "2147483647" are well defined (this method will return true). Setting
   * -txindex=2147483648 on most systems, however, is probably undefined.
   *
   * For a more extensive discussion of this topic (and a wide range of opinions
   * on the Right Way to change this code), see PR12713.
   */
  static bool InterpretBool(const std::string &strValue) {
      if (strValue.empty()) {
          return true;
      }
      return (atoi(strValue) != 0);
  }
  
  static std::string SettingName(const std::string &arg) {
      return arg.size() > 0 && arg[0] == '-' ? arg.substr(1) : arg;
  }
  
  /**
   * Interpret -nofoo as if the user supplied -foo=0.
   *
   * This method also tracks when the -no form was supplied, and if so, checks
   * whether there was a double-negative (-nofoo=0 -> -foo=1).
   *
   * If there was not a double negative, it removes the "no" from the key
   * and returns false.
   *
   * If there was a double negative, it removes "no" from the key, and
   * returns true.
   *
   * If there was no "no", it returns the string value untouched.
   *
   * Where an option was negated can be later checked using the IsArgNegated()
   * method. One use case for this is to have a way to disable options that are
   * not normally boolean (e.g. using -nodebuglogfile to request that debug log
   * output is not sent to any file at all).
   */
  
  static util::SettingsValue InterpretOption(std::string &section,
                                             std::string &key,
                                             const std::string &value) {
      // Split section name from key name for keys like "testnet.foo" or
      // "regtest.bar"
      size_t option_index = key.find('.');
      if (option_index != std::string::npos) {
          section = key.substr(0, option_index);
          key.erase(0, option_index + 1);
      }
      if (key.substr(0, 2) == "no") {
          key.erase(0, 2);
          // Double negatives like -nofoo=0 are supported (but discouraged)
          if (!InterpretBool(value)) {
              LogPrintf("Warning: parsed potentially confusing double-negative "
                        "-%s=%s\n",
                        key, value);
              return true;
          }
          return false;
      }
      return value;
  }
  
  /**
   * Check settings value validity according to flags.
   *
   * TODO: Add more meaningful error checks here in the future
   * See "here's how the flags are meant to behave" in
   * https://github.com/bitcoin/bitcoin/pull/16097#issuecomment-514627823
   */
  static bool CheckValid(const std::string &key, const util::SettingsValue &val,
                         unsigned int flags, std::string &error) {
      if (val.isBool() && !(flags & ArgsManager::ALLOW_BOOL)) {
          error = strprintf(
              "Negating of -%s is meaningless and therefore forbidden", key);
          return false;
      }
      return true;
  }
  
  // Define default constructor and destructor that are not inline, so code
  // instantiating this class doesn't need to #include class definitions for all
  // members. For example, m_settings has an internal dependency on univalue.
  ArgsManager::ArgsManager() {}
  ArgsManager::~ArgsManager() {}
  
  const std::set<std::string> ArgsManager::GetUnsuitableSectionOnlyArgs() const {
      std::set<std::string> unsuitables;
  
      LOCK(cs_args);
  
      // if there's no section selected, don't worry
      if (m_network.empty()) {
          return std::set<std::string>{};
      }
  
      // if it's okay to use the default section for this network, don't worry
      if (m_network == CBaseChainParams::MAIN) {
          return std::set<std::string>{};
      }
  
      for (const auto &arg : m_network_only_args) {
          if (OnlyHasDefaultSectionSetting(m_settings, m_network,
                                           SettingName(arg))) {
              unsuitables.insert(arg);
          }
      }
      return unsuitables;
  }
  
  const std::list<SectionInfo> ArgsManager::GetUnrecognizedSections() const {
      // Section names to be recognized in the config file.
      static const std::set<std::string> available_sections{
          CBaseChainParams::REGTEST, CBaseChainParams::TESTNET,
          CBaseChainParams::MAIN};
  
      LOCK(cs_args);
      std::list<SectionInfo> unrecognized = m_config_sections;
      unrecognized.remove_if([](const SectionInfo &appeared) {
          return available_sections.find(appeared.m_name) !=
                 available_sections.end();
      });
      return unrecognized;
  }
  
  void ArgsManager::SelectConfigNetwork(const std::string &network) {
      LOCK(cs_args);
      m_network = network;
  }
  
  bool ParseKeyValue(std::string &key, std::string &val) {
      size_t is_index = key.find('=');
      if (is_index != std::string::npos) {
          val = key.substr(is_index + 1);
          key.erase(is_index);
      }
  #ifdef WIN32
      key = ToLower(key);
      if (key[0] == '/') {
          key[0] = '-';
      }
  #endif
  
      if (key[0] != '-') {
          return false;
      }
  
      // Transform --foo to -foo
      if (key.length() > 1 && key[1] == '-') {
          key.erase(0, 1);
      }
      return true;
  }
  
  bool ArgsManager::ParseParameters(int argc, const char *const argv[],
                                    std::string &error) {
      LOCK(cs_args);
      m_settings.command_line_options.clear();
  
      for (int i = 1; i < argc; i++) {
          std::string key(argv[i]);
          if (key == "-") {
              // bitcoin-tx using stdin
              break;
          }
          std::string val;
          if (!ParseKeyValue(key, val)) {
              break;
          }
  
          // Transform -foo to foo
          key.erase(0, 1);
          std::string section;
          util::SettingsValue value = InterpretOption(section, key, val);
          std::optional<unsigned int> flags = GetArgFlags('-' + key);
  
          // Unknown command line options and command line options with dot
          // characters (which are returned from InterpretOption with nonempty
          // section strings) are not valid.
          if (!flags || !section.empty()) {
              error = strprintf("Invalid parameter %s", argv[i]);
              return false;
          }
  
          if (!CheckValid(key, value, *flags, error)) {
              return false;
          }
  
          m_settings.command_line_options[key].push_back(value);
      }
  
      // we do not allow -includeconf from command line
      bool success = true;
      if (auto *includes =
              util::FindKey(m_settings.command_line_options, "includeconf")) {
          for (const auto &include : util::SettingsSpan(*includes)) {
              error +=
                  "-includeconf cannot be used from commandline; -includeconf=" +
                  include.get_str() + "\n";
              success = false;
          }
      }
      return success;
  }
  
  std::optional<unsigned int>
  ArgsManager::GetArgFlags(const std::string &name) const {
      LOCK(cs_args);
      for (const auto &arg_map : m_available_args) {
          const auto search = arg_map.second.find(name);
          if (search != arg_map.second.end()) {
              return search->second.m_flags;
          }
      }
      return std::nullopt;
  }
  
  std::vector<std::string> ArgsManager::GetArgs(const std::string &strArg) const {
      std::vector<std::string> result;
      for (const util::SettingsValue &value : GetSettingsList(strArg)) {
          result.push_back(
              value.isFalse() ? "0" : value.isTrue() ? "1" : value.get_str());
      }
      return result;
  }
  
  bool ArgsManager::IsArgSet(const std::string &strArg) const {
      return !GetSetting(strArg).isNull();
  }
  
  bool ArgsManager::InitSettings(std::string &error) {
      if (!GetSettingsPath()) {
          return true; // Do nothing if settings file disabled.
      }
  
      std::vector<std::string> errors;
      if (!ReadSettingsFile(&errors)) {
          error = strprintf("Failed loading settings file:\n- %s\n",
                            Join(errors, "\n- "));
          return false;
      }
      if (!WriteSettingsFile(&errors)) {
          error = strprintf("Failed saving settings file:\n- %s\n",
                            Join(errors, "\n- "));
          return false;
      }
      return true;
  }
  
  bool ArgsManager::GetSettingsPath(fs::path *filepath, bool temp) const {
      if (IsArgNegated("-settings")) {
          return false;
      }
      if (filepath) {
          std::string settings = GetArg("-settings", BITCOIN_SETTINGS_FILENAME);
          *filepath = fs::absolute(temp ? settings + ".tmp" : settings,
                                   GetDataDir(/* net_specific= */ true));
      }
      return true;
  }
  
  static void SaveErrors(const std::vector<std::string> errors,
                         std::vector<std::string> *error_out) {
      for (const auto &error : errors) {
          if (error_out) {
              error_out->emplace_back(error);
          } else {
              LogPrintf("%s\n", error);
          }
      }
  }
  
  bool ArgsManager::ReadSettingsFile(std::vector<std::string> *errors) {
      fs::path path;
      if (!GetSettingsPath(&path, /* temp= */ false)) {
          return true; // Do nothing if settings file disabled.
      }
  
      LOCK(cs_args);
      m_settings.rw_settings.clear();
      std::vector<std::string> read_errors;
      if (!util::ReadSettings(path, m_settings.rw_settings, read_errors)) {
          SaveErrors(read_errors, errors);
          return false;
      }
      return true;
  }
  
  bool ArgsManager::WriteSettingsFile(std::vector<std::string> *errors) const {
      fs::path path, path_tmp;
      if (!GetSettingsPath(&path, /* temp= */ false) ||
          !GetSettingsPath(&path_tmp, /* temp= */ true)) {
          throw std::logic_error("Attempt to write settings file when dynamic "
                                 "settings are disabled.");
      }
  
      LOCK(cs_args);
      std::vector<std::string> write_errors;
      if (!util::WriteSettings(path_tmp, m_settings.rw_settings, write_errors)) {
          SaveErrors(write_errors, errors);
          return false;
      }
      if (!RenameOver(path_tmp, path)) {
          SaveErrors({strprintf("Failed renaming settings file %s to %s\n",
                                path_tmp.string(), path.string())},
                     errors);
          return false;
      }
      return true;
  }
  
  bool ArgsManager::IsArgNegated(const std::string &strArg) const {
      return GetSetting(strArg).isFalse();
  }
  
  std::string ArgsManager::GetArg(const std::string &strArg,
                                  const std::string &strDefault) const {
      const util::SettingsValue value = GetSetting(strArg);
      return value.isNull()
                 ? strDefault
                 : value.isFalse() ? "0" : value.isTrue() ? "1" : value.get_str();
  }
  
  int64_t ArgsManager::GetArg(const std::string &strArg, int64_t nDefault) const {
      const util::SettingsValue value = GetSetting(strArg);
      return value.isNull()
                 ? nDefault
                 : value.isFalse()
                       ? 0
                       : value.isTrue() ? 1
                                        : value.isNum() ? value.get_int64()
                                                        : atoi64(value.get_str());
  }
  
  bool ArgsManager::GetBoolArg(const std::string &strArg, bool fDefault) const {
      const util::SettingsValue value = GetSetting(strArg);
      return value.isNull() ? fDefault
                            : value.isBool() ? value.get_bool()
                                             : InterpretBool(value.get_str());
  }
  
  bool ArgsManager::SoftSetArg(const std::string &strArg,
                               const std::string &strValue) {
      LOCK(cs_args);
      if (IsArgSet(strArg)) {
          return false;
      }
      ForceSetArg(strArg, strValue);
      return true;
  }
  
  bool ArgsManager::SoftSetBoolArg(const std::string &strArg, bool fValue) {
      if (fValue) {
          return SoftSetArg(strArg, std::string("1"));
      } else {
          return SoftSetArg(strArg, std::string("0"));
      }
  }
  
  void ArgsManager::ForceSetArg(const std::string &strArg,
                                const std::string &strValue) {
      LOCK(cs_args);
      m_settings.forced_settings[SettingName(strArg)] = strValue;
  }
  
  /**
   * This function is only used for testing purpose so
   * so we should not worry about element uniqueness and
   * integrity of mapMultiArgs data structure
   */
  void ArgsManager::ForceSetMultiArg(const std::string &strArg,
                                     const std::vector<std::string> &values) {
      LOCK(cs_args);
      util::SettingsValue value;
      value.setArray();
      for (const std::string &s : values) {
          value.push_back(s);
      }
  
      m_settings.forced_settings[SettingName(strArg)] = value;
  }
  
  void ArgsManager::AddArg(const std::string &name, const std::string &help,
                           unsigned int flags, const OptionsCategory &cat) {
      // Split arg name from its help param
      size_t eq_index = name.find('=');
      if (eq_index == std::string::npos) {
          eq_index = name.size();
      }
      std::string arg_name = name.substr(0, eq_index);
  
      LOCK(cs_args);
      std::map<std::string, Arg> &arg_map = m_available_args[cat];
      auto ret = arg_map.emplace(
          arg_name,
          Arg{name.substr(eq_index, name.size() - eq_index), help, flags});
      // Make sure an insertion actually happened.
      assert(ret.second);
  
      if (flags & ArgsManager::NETWORK_ONLY) {
          m_network_only_args.emplace(arg_name);
      }
  }
  
  void ArgsManager::AddHiddenArgs(const std::vector<std::string> &names) {
      for (const std::string &name : names) {
          AddArg(name, "", ArgsManager::ALLOW_ANY, OptionsCategory::HIDDEN);
      }
  }
  
  void ArgsManager::ClearForcedArg(const std::string &strArg) {
      LOCK(cs_args);
      m_settings.forced_settings.erase(SettingName(strArg));
  }
  
  std::string ArgsManager::GetHelpMessage() const {
      const bool show_debug = gArgs.GetBoolArg("-help-debug", false);
  
      std::string usage = "";
      LOCK(cs_args);
      for (const auto &arg_map : m_available_args) {
          switch (arg_map.first) {
              case OptionsCategory::OPTIONS:
                  usage += HelpMessageGroup("Options:");
                  break;
              case OptionsCategory::CONNECTION:
                  usage += HelpMessageGroup("Connection options:");
                  break;
              case OptionsCategory::ZMQ:
                  usage += HelpMessageGroup("ZeroMQ notification options:");
                  break;
              case OptionsCategory::DEBUG_TEST:
                  usage += HelpMessageGroup("Debugging/Testing options:");
                  break;
              case OptionsCategory::NODE_RELAY:
                  usage += HelpMessageGroup("Node relay options:");
                  break;
              case OptionsCategory::BLOCK_CREATION:
                  usage += HelpMessageGroup("Block creation options:");
                  break;
              case OptionsCategory::RPC:
                  usage += HelpMessageGroup("RPC server options:");
                  break;
              case OptionsCategory::WALLET:
                  usage += HelpMessageGroup("Wallet options:");
                  break;
              case OptionsCategory::WALLET_DEBUG_TEST:
                  if (show_debug) {
                      usage +=
                          HelpMessageGroup("Wallet debugging/testing options:");
                  }
                  break;
              case OptionsCategory::CHAINPARAMS:
                  usage += HelpMessageGroup("Chain selection options:");
                  break;
              case OptionsCategory::GUI:
                  usage += HelpMessageGroup("UI Options:");
                  break;
              case OptionsCategory::COMMANDS:
                  usage += HelpMessageGroup("Commands:");
                  break;
              case OptionsCategory::REGISTER_COMMANDS:
                  usage += HelpMessageGroup("Register Commands:");
                  break;
              default:
                  break;
          }
  
          // When we get to the hidden options, stop
          if (arg_map.first == OptionsCategory::HIDDEN) {
              break;
          }
  
          for (const auto &arg : arg_map.second) {
              if (show_debug || !(arg.second.m_flags & ArgsManager::DEBUG_ONLY)) {
                  std::string name;
                  if (arg.second.m_help_param.empty()) {
                      name = arg.first;
                  } else {
                      name = arg.first + arg.second.m_help_param;
                  }
                  usage += HelpMessageOpt(name, arg.second.m_help_text);
              }
          }
      }
      return usage;
  }
  
  bool HelpRequested(const ArgsManager &args) {
      return args.IsArgSet("-?") || args.IsArgSet("-h") ||
             args.IsArgSet("-help") || args.IsArgSet("-help-debug");
  }
  
  void SetupHelpOptions(ArgsManager &args) {
      args.AddArg("-?", "Print this help message and exit", false,
                  OptionsCategory::OPTIONS);
      args.AddHiddenArgs({"-h", "-help"});
  }
  
  static const int screenWidth = 79;
  static const int optIndent = 2;
  static const int msgIndent = 7;
  
  std::string HelpMessageGroup(const std::string &message) {
      return std::string(message) + std::string("\n\n");
  }
  
  std::string HelpMessageOpt(const std::string &option,
                             const std::string &message) {
      return std::string(optIndent, ' ') + std::string(option) +
             std::string("\n") + std::string(msgIndent, ' ') +
             FormatParagraph(message, screenWidth - msgIndent, msgIndent) +
             std::string("\n\n");
  }
  
  static std::string FormatException(const std::exception *pex,
                                     const char *pszThread) {
  #ifdef WIN32
      char pszModule[MAX_PATH] = "";
      GetModuleFileNameA(nullptr, pszModule, sizeof(pszModule));
  #else
      const char *pszModule = "bitcoin";
  #endif
      if (pex) {
          return strprintf("EXCEPTION: %s       \n%s       \n%s in %s       \n",
                           typeid(*pex).name(), pex->what(), pszModule,
                           pszThread);
      } else {
          return strprintf("UNKNOWN EXCEPTION       \n%s in %s       \n",
                           pszModule, pszThread);
      }
  }
  
  void PrintExceptionContinue(const std::exception *pex, const char *pszThread) {
      std::string message = FormatException(pex, pszThread);
      LogPrintf("\n\n************************\n%s\n", message);
      tfm::format(std::cerr, "\n\n************************\n%s\n", message);
  }
  
  fs::path GetDefaultDataDir() {
  // Windows < Vista: C:\Documents and Settings\Username\Application Data\Bitcoin
  // Windows >= Vista: C:\Users\Username\AppData\Roaming\Bitcoin
  // Mac: ~/Library/Application Support/Bitcoin
  // Unix: ~/.bitcoin
  #ifdef WIN32
      // Windows
      return GetSpecialFolderPath(CSIDL_APPDATA) / "Bitcoin";
  #else
      fs::path pathRet;
      char *pszHome = getenv("HOME");
      if (pszHome == nullptr || strlen(pszHome) == 0) {
          pathRet = fs::path("/");
      } else {
          pathRet = fs::path(pszHome);
      }
  #ifdef MAC_OSX
      // Mac
      return pathRet / "Library/Application Support/Bitcoin";
  #else
      // Unix
      return pathRet / ".bitcoin";
  #endif
  #endif
  }
  
  static fs::path g_blocks_path_cache_net_specific;
  static fs::path pathCached;
  static fs::path pathCachedNetSpecific;
  static RecursiveMutex csPathCached;
  
  const fs::path &GetBlocksDir() {
      LOCK(csPathCached);
      fs::path &path = g_blocks_path_cache_net_specific;
  
      // Cache the path to avoid calling fs::create_directories on every call of
      // this function
      if (!path.empty()) {
          return path;
      }
  
      if (gArgs.IsArgSet("-blocksdir")) {
          path = fs::system_complete(gArgs.GetArg("-blocksdir", ""));
          if (!fs::is_directory(path)) {
              path = "";
              return path;
          }
      } else {
          path = GetDataDir(false);
      }
  
      path /= BaseParams().DataDir();
      path /= "blocks";
      fs::create_directories(path);
      return path;
  }
  
  const fs::path &GetDataDir(bool fNetSpecific) {
      LOCK(csPathCached);
      fs::path &path = fNetSpecific ? pathCachedNetSpecific : pathCached;
  
      // Cache the path to avoid calling fs::create_directories on every call of
      // this function
      if (!path.empty()) {
          return path;
      }
  
      std::string datadir = gArgs.GetArg("-datadir", "");
      if (!datadir.empty()) {
          path = fs::system_complete(datadir);
          if (!fs::is_directory(path)) {
              path = "";
              return path;
          }
      } else {
          path = GetDefaultDataDir();
      }
  
      if (fNetSpecific) {
          path /= BaseParams().DataDir();
      }
  
      if (fs::create_directories(path)) {
          // This is the first run, create wallets subdirectory too
          //
          // TODO: this is an ugly way to create the wallets/ directory and
          // really shouldn't be done here. Once this is fixed, please
          // also remove the corresponding line in bitcoind.cpp AppInit.
          // See more info at:
          // https://reviews.bitcoinabc.org/D3312
          fs::create_directories(path / "wallets");
      }
  
      return path;
  }
  
  bool CheckDataDirOption() {
      std::string datadir = gArgs.GetArg("-datadir", "");
      return datadir.empty() || fs::is_directory(fs::system_complete(datadir));
  }
  
  void ClearDatadirCache() {
      LOCK(csPathCached);
  
      pathCached = fs::path();
      pathCachedNetSpecific = fs::path();
      g_blocks_path_cache_net_specific = fs::path();
  }
  
  fs::path GetConfigFile(const std::string &confPath) {
      return AbsPathForConfigVal(fs::path(confPath), false);
  }
  
  static bool
  GetConfigOptions(std::istream &stream, const std::string &filepath,
                   std::string &error,
                   std::vector<std::pair<std::string, std::string>> &options,
                   std::list<SectionInfo> &sections) {
      std::string str, prefix;
      std::string::size_type pos;
      int linenr = 1;
      while (std::getline(stream, str)) {
          bool used_hash = false;
          if ((pos = str.find('#')) != std::string::npos) {
              str = str.substr(0, pos);
              used_hash = true;
          }
          const static std::string pattern = " \t\r\n";
          str = TrimString(str, pattern);
          if (!str.empty()) {
              if (*str.begin() == '[' && *str.rbegin() == ']') {
                  const std::string section = str.substr(1, str.size() - 2);
                  sections.emplace_back(SectionInfo{section, filepath, linenr});
                  prefix = section + '.';
              } else if (*str.begin() == '-') {
                  error = strprintf(
                      "parse error on line %i: %s, options in configuration file "
                      "must be specified without leading -",
                      linenr, str);
                  return false;
              } else if ((pos = str.find('=')) != std::string::npos) {
                  std::string name =
                      prefix + TrimString(str.substr(0, pos), pattern);
                  std::string value = TrimString(str.substr(pos + 1), pattern);
                  if (used_hash &&
                      name.find("rpcpassword") != std::string::npos) {
                      error = strprintf(
                          "parse error on line %i, using # in rpcpassword can be "
                          "ambiguous and should be avoided",
                          linenr);
                      return false;
                  }
                  options.emplace_back(name, value);
                  if ((pos = name.rfind('.')) != std::string::npos &&
                      prefix.length() <= pos) {
                      sections.emplace_back(
                          SectionInfo{name.substr(0, pos), filepath, linenr});
                  }
              } else {
                  error = strprintf("parse error on line %i: %s", linenr, str);
                  if (str.size() >= 2 && str.substr(0, 2) == "no") {
                      error += strprintf(", if you intended to specify a negated "
                                         "option, use %s=1 instead",
                                         str);
                  }
                  return false;
              }
          }
          ++linenr;
      }
      return true;
  }
  
  bool ArgsManager::ReadConfigStream(std::istream &stream,
                                     const std::string &filepath,
                                     std::string &error,
                                     bool ignore_invalid_keys) {
      LOCK(cs_args);
      std::vector<std::pair<std::string, std::string>> options;
      if (!GetConfigOptions(stream, filepath, error, options,
                            m_config_sections)) {
          return false;
      }
      for (const std::pair<std::string, std::string> &option : options) {
          std::string section;
          std::string key = option.first;
          util::SettingsValue value =
              InterpretOption(section, key, option.second);
          std::optional<unsigned int> flags = GetArgFlags('-' + key);
          if (flags) {
              if (!CheckValid(key, value, *flags, error)) {
                  return false;
              }
              m_settings.ro_config[section][key].push_back(value);
          } else {
              if (ignore_invalid_keys) {
                  LogPrintf("Ignoring unknown configuration value %s\n",
                            option.first);
              } else {
                  error = strprintf("Invalid configuration value %s",
                                    option.first.c_str());
                  return false;
              }
          }
      }
      return true;
  }
  
  bool ArgsManager::ReadConfigFiles(std::string &error,
                                    bool ignore_invalid_keys) {
      {
          LOCK(cs_args);
          m_settings.ro_config.clear();
          m_config_sections.clear();
      }
  
      const std::string confPath = GetArg("-conf", BITCOIN_CONF_FILENAME);
      fsbridge::ifstream stream(GetConfigFile(confPath));
  
      // ok to not have a config file
      if (stream.good()) {
          if (!ReadConfigStream(stream, confPath, error, ignore_invalid_keys)) {
              return false;
          }
          // `-includeconf` cannot be included in the command line arguments
          // except as `-noincludeconf` (which indicates that no included conf
          // file should be used).
          bool use_conf_file{true};
          {
              LOCK(cs_args);
              if (auto *includes = util::FindKey(m_settings.command_line_options,
                                                 "includeconf")) {
                  // ParseParameters() fails if a non-negated -includeconf is
                  // passed on the command-line
                  assert(util::SettingsSpan(*includes).last_negated());
                  use_conf_file = false;
              }
          }
          if (use_conf_file) {
              std::string chain_id = GetChainName();
              std::vector<std::string> conf_file_names;
  
              auto add_includes = [&](const std::string &network,
                                      size_t skip = 0) {
                  size_t num_values = 0;
                  LOCK(cs_args);
                  if (auto *section =
                          util::FindKey(m_settings.ro_config, network)) {
                      if (auto *values = util::FindKey(*section, "includeconf")) {
                          for (size_t i = std::max(
                                   skip, util::SettingsSpan(*values).negated());
                               i < values->size(); ++i) {
                              conf_file_names.push_back((*values)[i].get_str());
                          }
                          num_values = values->size();
                      }
                  }
                  return num_values;
              };
  
              // We haven't set m_network yet (that happens in SelectParams()), so
              // manually check for network.includeconf args.
              const size_t chain_includes = add_includes(chain_id);
              const size_t default_includes = add_includes({});
  
              for (const std::string &conf_file_name : conf_file_names) {
                  fsbridge::ifstream conf_file_stream(
                      GetConfigFile(conf_file_name));
                  if (conf_file_stream.good()) {
                      if (!ReadConfigStream(conf_file_stream, conf_file_name,
                                            error, ignore_invalid_keys)) {
                          return false;
                      }
                      LogPrintf("Included configuration file %s\n",
                                conf_file_name);
                  } else {
                      error = "Failed to include configuration file " +
                              conf_file_name;
                      return false;
                  }
              }
  
              // Warn about recursive -includeconf
              conf_file_names.clear();
              add_includes(chain_id, /* skip= */ chain_includes);
              add_includes({}, /* skip= */ default_includes);
              std::string chain_id_final = GetChainName();
              if (chain_id_final != chain_id) {
                  // Also warn about recursive includeconf for the chain that was
                  // specified in one of the includeconfs
                  add_includes(chain_id_final);
              }
              for (const std::string &conf_file_name : conf_file_names) {
                  tfm::format(std::cerr,
                              "warning: -includeconf cannot be used from "
                              "included files; ignoring -includeconf=%s\n",
                              conf_file_name);
              }
          }
      }
  
      // If datadir is changed in .conf file:
      ClearDatadirCache();
      if (!CheckDataDirOption()) {
          error = strprintf("specified data directory \"%s\" does not exist.",
                            gArgs.GetArg("-datadir", "").c_str());
          return false;
      }
      return true;
  }
  
  std::string ArgsManager::GetChainName() const {
      auto get_net = [&](const std::string &arg) {
          LOCK(cs_args);
          util::SettingsValue value =
              util::GetSetting(m_settings, /* section= */ "", SettingName(arg),
                               /* ignore_default_section_config= */ false,
                               /* get_chain_name= */ true);
          return value.isNull() ? false
                                : value.isBool() ? value.get_bool()
                                                 : InterpretBool(value.get_str());
      };
  
      const bool fRegTest = get_net("-regtest");
      const bool fTestNet = get_net("-testnet");
      const bool is_chain_arg_set = IsArgSet("-chain");
  
      if (int(is_chain_arg_set) + int(fRegTest) + int(fTestNet) > 1) {
          throw std::runtime_error("Invalid combination of -regtest, -testnet "
                                   "and -chain. Can use at most one.");
      }
      if (fRegTest) {
          return CBaseChainParams::REGTEST;
      }
      if (fTestNet) {
          return CBaseChainParams::TESTNET;
      }
      return GetArg("-chain", CBaseChainParams::MAIN);
  }
  
  bool ArgsManager::UseDefaultSection(const std::string &arg) const {
      return m_network == CBaseChainParams::MAIN ||
             m_network_only_args.count(arg) == 0;
  }
  
  util::SettingsValue ArgsManager::GetSetting(const std::string &arg) const {
      LOCK(cs_args);
      return util::GetSetting(m_settings, m_network, SettingName(arg),
                              !UseDefaultSection(arg),
                              /* get_chain_name= */ false);
  }
  
  std::vector<util::SettingsValue>
  ArgsManager::GetSettingsList(const std::string &arg) const {
      LOCK(cs_args);
      return util::GetSettingsList(m_settings, m_network, SettingName(arg),
                                   !UseDefaultSection(arg));
  }
  
  void ArgsManager::logArgsPrefix(
      const std::string &prefix, const std::string &section,
      const std::map<std::string, std::vector<util::SettingsValue>> &args) const {
      std::string section_str = section.empty() ? "" : "[" + section + "] ";
      for (const auto &arg : args) {
          for (const auto &value : arg.second) {
              std::optional<unsigned int> flags = GetArgFlags('-' + arg.first);
              if (flags) {
                  std::string value_str =
                      (*flags & SENSITIVE) ? "****" : value.write();
                  LogPrintf("%s %s%s=%s\n", prefix, section_str, arg.first,
                            value_str);
              }
          }
      }
  }
  
  void ArgsManager::LogArgs() const {
      LOCK(cs_args);
      for (const auto &section : m_settings.ro_config) {
          logArgsPrefix("Config file arg:", section.first, section.second);
      }
      for (const auto &setting : m_settings.rw_settings) {
          LogPrintf("Setting file arg: %s = %s\n", setting.first,
                    setting.second.write());
      }
      logArgsPrefix("Command-line arg:", "", m_settings.command_line_options);
  }
  
  bool RenameOver(fs::path src, fs::path dest) {
  #ifdef WIN32
      return MoveFileExA(src.string().c_str(), dest.string().c_str(),
                         MOVEFILE_REPLACE_EXISTING) != 0;
  #else
      int rc = std::rename(src.string().c_str(), dest.string().c_str());
      return (rc == 0);
  #endif /* WIN32 */
  }
  
  /**
   * Ignores exceptions thrown by Boost's create_directories if the requested
   * directory exists. Specifically handles case where path p exists, but it
   * wasn't possible for the user to write to the parent directory.
   */
  bool TryCreateDirectories(const fs::path &p) {
      try {
          return fs::create_directories(p);
      } catch (const fs::filesystem_error &) {
          if (!fs::exists(p) || !fs::is_directory(p)) {
              throw;
          }
      }
  
      // create_directory didn't create the directory, it had to have existed
      // already.
      return false;
  }
  
  bool FileCommit(FILE *file) {
      // harmless if redundantly called
      if (fflush(file) != 0) {
          LogPrintf("%s: fflush failed: %d\n", __func__, errno);
          return false;
      }
  #ifdef WIN32
      HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
      if (FlushFileBuffers(hFile) == 0) {
          LogPrintf("%s: FlushFileBuffers failed: %d\n", __func__,
                    GetLastError());
          return false;
      }
  #else
  #if defined(__linux__) || defined(__NetBSD__)
      // Ignore EINVAL for filesystems that don't support sync
      if (fdatasync(fileno(file)) != 0 && errno != EINVAL) {
          LogPrintf("%s: fdatasync failed: %d\n", __func__, errno);
          return false;
      }
  #elif defined(MAC_OSX) && defined(F_FULLFSYNC)
      // Manpage says "value other than -1" is returned on success
      if (fcntl(fileno(file), F_FULLFSYNC, 0) == -1) {
          LogPrintf("%s: fcntl F_FULLFSYNC failed: %d\n", __func__, errno);
          return false;
      }
  #else
      if (fsync(fileno(file)) != 0 && errno != EINVAL) {
          LogPrintf("%s: fsync failed: %d\n", __func__, errno);
          return false;
      }
  #endif
  #endif
      return true;
  }
  
  bool TruncateFile(FILE *file, unsigned int length) {
  #if defined(WIN32)
      return _chsize(_fileno(file), length) == 0;
  #else
      return ftruncate(fileno(file), length) == 0;
  #endif
  }
  
  /**
   * This function tries to raise the file descriptor limit to the requested
   * number. It returns the actual file descriptor limit (which may be more or
   * less than nMinFD)
   */
  int RaiseFileDescriptorLimit(int nMinFD) {
  #if defined(WIN32)
      return 8192;
  #else
      struct rlimit limitFD;
      if (getrlimit(RLIMIT_NOFILE, &limitFD) != -1) {
          if (limitFD.rlim_cur < (rlim_t)nMinFD) {
              limitFD.rlim_cur = nMinFD;
              if (limitFD.rlim_cur > limitFD.rlim_max) {
                  limitFD.rlim_cur = limitFD.rlim_max;
              }
              setrlimit(RLIMIT_NOFILE, &limitFD);
              getrlimit(RLIMIT_NOFILE, &limitFD);
          }
          return limitFD.rlim_cur;
      }
      // getrlimit failed, assume it's fine.
      return nMinFD;
  #endif
  }
  
  /**
   * This function tries to make a particular range of a file allocated
   * (corresponding to disk space) it is advisory, and the range specified in the
   * arguments will never contain live data.
   */
  void AllocateFileRange(FILE *file, unsigned int offset, unsigned int length) {
  #if defined(WIN32)
      // Windows-specific version.
      HANDLE hFile = (HANDLE)_get_osfhandle(_fileno(file));
      LARGE_INTEGER nFileSize;
      int64_t nEndPos = (int64_t)offset + length;
      nFileSize.u.LowPart = nEndPos & 0xFFFFFFFF;
      nFileSize.u.HighPart = nEndPos >> 32;
      SetFilePointerEx(hFile, nFileSize, 0, FILE_BEGIN);
      SetEndOfFile(hFile);
  #elif defined(MAC_OSX)
      // OSX specific version
      // NOTE: Contrary to other OS versions, the OSX version assumes that
      // NOTE: offset is the size of the file.
      fstore_t fst;
      fst.fst_flags = F_ALLOCATECONTIG;
      fst.fst_posmode = F_PEOFPOSMODE;
      fst.fst_offset = 0;
      // mac os fst_length takes the number of free bytes to allocate,
      // not the desired file size
      fst.fst_length = length;
      fst.fst_bytesalloc = 0;
      if (fcntl(fileno(file), F_PREALLOCATE, &fst) == -1) {
          fst.fst_flags = F_ALLOCATEALL;
          fcntl(fileno(file), F_PREALLOCATE, &fst);
      }
      ftruncate(fileno(file), static_cast<off_t>(offset) + length);
  #elif defined(HAVE_POSIX_FALLOCATE)
      // Version using posix_fallocate
      off_t nEndPos = (off_t)offset + length;
      posix_fallocate(fileno(file), 0, nEndPos);
  #else
      // Fallback version
      // TODO: just write one byte per block
      static const char buf[65536] = {};
      if (fseek(file, offset, SEEK_SET)) {
          return;
      }
      while (length > 0) {
          unsigned int now = 65536;
          if (length < now) {
              now = length;
          }
          // Allowed to fail; this function is advisory anyway.
          fwrite(buf, 1, now, file);
          length -= now;
      }
  #endif
  }
  
  #ifdef WIN32
  fs::path GetSpecialFolderPath(int nFolder, bool fCreate) {
      WCHAR pszPath[MAX_PATH] = L"";
  
      if (SHGetSpecialFolderPathW(nullptr, pszPath, nFolder, fCreate)) {
          return fs::path(pszPath);
      }
  
      LogPrintf(
          "SHGetSpecialFolderPathW() failed, could not obtain requested path.\n");
      return fs::path("");
  }
  #endif
  
  #ifndef WIN32
  std::string ShellEscape(const std::string &arg) {
      std::string escaped = arg;
      boost::replace_all(escaped, "'", "'\"'\"'");
      return "'" + escaped + "'";
  }
  #endif
  
  #if defined(HAVE_SYSTEM)
  void runCommand(const std::string &strCommand) {
      if (strCommand.empty()) {
          return;
      }
  #ifndef WIN32
      int nErr = ::system(strCommand.c_str());
  #else
      int nErr = ::_wsystem(
          std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>, wchar_t>()
              .from_bytes(strCommand)
              .c_str());
  #endif
      if (nErr) {
          LogPrintf("runCommand error: system(%s) returned %d\n", strCommand,
                    nErr);
      }
  }
  #endif
  
  void SetupEnvironment() {
  #ifdef HAVE_MALLOPT_ARENA_MAX
      // glibc-specific: On 32-bit systems set the number of arenas to 1. By
      // default, since glibc 2.10, the C library will create up to two heap
      // arenas per core. This is known to cause excessive virtual address space
      // usage in our usage. Work around it by setting the maximum number of
      // arenas to 1.
      if (sizeof(void *) == 4) {
          mallopt(M_ARENA_MAX, 1);
      }
  #endif
  // On most POSIX systems (e.g. Linux, but not BSD) the environment's locale may
  // be invalid, in which case the "C.UTF-8" locale is used as fallback.
  #if !defined(WIN32) && !defined(MAC_OSX) && !defined(__FreeBSD__) &&           \
      !defined(__OpenBSD__)
      try {
          // Raises a runtime error if current locale is invalid.
          std::locale("");
      } catch (const std::runtime_error &) {
          setenv("LC_ALL", "C.UTF-8", 1);
      }
  #elif defined(WIN32)
      // Set the default input/output charset is utf-8
      SetConsoleCP(CP_UTF8);
      SetConsoleOutputCP(CP_UTF8);
  #endif
      // The path locale is lazy initialized and to avoid deinitialization errors
      // in multithreading environments, it is set explicitly by the main thread.
      // A dummy locale is used to extract the internal default locale, used by
      // fs::path, which is then used to explicitly imbue the path.
      std::locale loc = fs::path::imbue(std::locale::classic());
  #ifndef WIN32
      fs::path::imbue(loc);
  #else
      fs::path::imbue(std::locale(loc, new std::codecvt_utf8_utf16<wchar_t>()));
  #endif
  }
  
  bool SetupNetworking() {
  #ifdef WIN32
      // Initialize Windows Sockets.
      WSADATA wsadata;
      int ret = WSAStartup(MAKEWORD(2, 2), &wsadata);
      if (ret != NO_ERROR || LOBYTE(wsadata.wVersion) != 2 ||
          HIBYTE(wsadata.wVersion) != 2) {
          return false;
      }
  #endif
      return true;
  }
  
  int GetNumCores() {
      return std::thread::hardware_concurrency();
  }
  
  std::string CopyrightHolders(const std::string &strPrefix) {
      return strPrefix + strprintf(_(COPYRIGHT_HOLDERS).translated,
                                   COPYRIGHT_HOLDERS_SUBSTITUTION);
  }
  
  // Obtain the application startup time (used for uptime calculation)
  int64_t GetStartupTime() {
      return nStartupTime;
  }
  
  fs::path AbsPathForConfigVal(const fs::path &path, bool net_specific) {
      if (path.is_absolute()) {
          return path;
      }
      return fs::absolute(path, GetDataDir(net_specific));
  }
  
  void ScheduleBatchPriority() {
  #ifdef SCHED_BATCH
      const static sched_param param{};
      if (pthread_setschedparam(pthread_self(), SCHED_BATCH, &param) != 0) {
          LogPrintf("Failed to pthread_setschedparam: %s\n", strerror(errno));
      }
  #endif
  }
  
  namespace util {
  #ifdef WIN32
  WinCmdLineArgs::WinCmdLineArgs() {
      wchar_t **wargv = CommandLineToArgvW(GetCommandLineW(), &argc);
      std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>, wchar_t> utf8_cvt;
      argv = new char *[argc];
      args.resize(argc);
      for (int i = 0; i < argc; i++) {
          args[i] = utf8_cvt.to_bytes(wargv[i]);
          argv[i] = &*args[i].begin();
      }
      LocalFree(wargv);
  }
  
  WinCmdLineArgs::~WinCmdLineArgs() {
      delete[] argv;
  }
  
  std::pair<int, char **> WinCmdLineArgs::get() {
      return std::make_pair(argc, argv);
  }
  #endif
  } // namespace util
  