From c8918f0c02a800d32bee8f5f633575e7fde7a8af Mon Sep 17 00:00:00 2001
From: EmelyanenkoK <emelyanenko.kirill@gmail.com>
Date: Wed, 27 Dec 2023 15:50:09 +0300
Subject: [PATCH] Write config.json using temp file (#839)

Co-authored-by: SpyCheese <mikle98@yandex.ru>
---
 dht-server/dht-server.cpp             | 17 +++++++++++++----
 dht-server/dht-server.hpp             |  3 +++
 validator-engine/validator-engine.cpp | 17 +++++++++++++----
 validator-engine/validator-engine.hpp |  5 ++++-
 4 files changed, 33 insertions(+), 9 deletions(-)

diff --git a/dht-server/dht-server.cpp b/dht-server/dht-server.cpp
index f729105f..37a158eb 100644
--- a/dht-server/dht-server.cpp
+++ b/dht-server/dht-server.cpp
@@ -572,6 +572,12 @@ void DhtServer::load_config(td::Promise<td::Unit> promise) {
     config_file_ = db_root_ + "/config.json";
   }
   auto conf_data_R = td::read_file(config_file_);
+  if (conf_data_R.is_error()) {
+    conf_data_R = td::read_file(temp_config_file());
+    if (conf_data_R.is_ok()) {
+      td::rename(temp_config_file(), config_file_).ensure();
+    }
+  }
   if (conf_data_R.is_error()) {
     auto P = td::PromiseCreator::lambda(
         [name = local_config_, new_name = config_file_, promise = std::move(promise)](td::Result<td::Unit> R) {
@@ -620,12 +626,15 @@ void DhtServer::load_config(td::Promise<td::Unit> promise) {
 void DhtServer::write_config(td::Promise<td::Unit> promise) {
   auto s = td::json_encode<std::string>(td::ToJson(*config_.tl().get()), true);
 
-  auto S = td::write_file(config_file_, s);
-  if (S.is_ok()) {
-    promise.set_value(td::Unit());
-  } else {
+  auto S = td::write_file(temp_config_file(), s);
+  if (S.is_error()) {
+    td::unlink(temp_config_file()).ignore();
     promise.set_error(std::move(S));
+    return;
   }
+  td::unlink(config_file_).ignore();
+  TRY_STATUS_PROMISE(promise, td::rename(temp_config_file(), config_file_));
+  promise.set_value(td::Unit());
 }
 
 td::Promise<ton::PublicKey> DhtServer::get_key_promise(td::MultiPromise::InitGuard &ig) {
diff --git a/dht-server/dht-server.hpp b/dht-server/dht-server.hpp
index bf24d621..5b81875b 100644
--- a/dht-server/dht-server.hpp
+++ b/dht-server/dht-server.hpp
@@ -109,6 +109,9 @@ class DhtServer : public td::actor::Actor {
   std::string local_config_ = "";
   std::string global_config_ = "ton-global.config";
   std::string config_file_;
+  std::string temp_config_file() const {
+    return config_file_ + ".tmp";
+  }
 
   std::string db_root_ = "/var/ton-work/db/";
 
diff --git a/validator-engine/validator-engine.cpp b/validator-engine/validator-engine.cpp
index 1d9223f2..e488504f 100644
--- a/validator-engine/validator-engine.cpp
+++ b/validator-engine/validator-engine.cpp
@@ -1595,6 +1595,12 @@ void ValidatorEngine::load_config(td::Promise<td::Unit> promise) {
     config_file_ = db_root_ + "/config.json";
   }
   auto conf_data_R = td::read_file(config_file_);
+  if (conf_data_R.is_error()) {
+    conf_data_R = td::read_file(temp_config_file());
+    if (conf_data_R.is_ok()) {
+      td::rename(temp_config_file(), config_file_).ensure();
+    }
+  }
   if (conf_data_R.is_error()) {
     auto P = td::PromiseCreator::lambda(
         [name = local_config_, new_name = config_file_, promise = std::move(promise)](td::Result<td::Unit> R) {
@@ -1643,12 +1649,15 @@ void ValidatorEngine::load_config(td::Promise<td::Unit> promise) {
 void ValidatorEngine::write_config(td::Promise<td::Unit> promise) {
   auto s = td::json_encode<std::string>(td::ToJson(*config_.tl().get()), true);
 
-  auto S = td::write_file(config_file_, s);
-  if (S.is_ok()) {
-    promise.set_value(td::Unit());
-  } else {
+  auto S = td::write_file(temp_config_file(), s);
+  if (S.is_error()) {
+    td::unlink(temp_config_file()).ignore();
     promise.set_error(std::move(S));
+    return;
   }
+  td::unlink(config_file_).ignore();
+  TRY_STATUS_PROMISE(promise, td::rename(temp_config_file(), config_file_));
+  promise.set_value(td::Unit());
 }
 
 td::Promise<ton::PublicKey> ValidatorEngine::get_key_promise(td::MultiPromise::InitGuard &ig) {
diff --git a/validator-engine/validator-engine.hpp b/validator-engine/validator-engine.hpp
index ebcd60c6..e59bb418 100644
--- a/validator-engine/validator-engine.hpp
+++ b/validator-engine/validator-engine.hpp
@@ -1,4 +1,4 @@
-/* 
+/*
     This file is part of TON Blockchain source code.
 
     TON Blockchain is free software; you can redistribute it and/or
@@ -152,6 +152,9 @@ class ValidatorEngine : public td::actor::Actor {
   std::string local_config_ = "";
   std::string global_config_ = "ton-global.config";
   std::string config_file_;
+  std::string temp_config_file() const {
+    return config_file_ + ".tmp";
+  }
 
   std::string fift_dir_ = "";