added mutex

src/users/add_user.cpp

@@ -61,10 +61,13 @@ void add_user(const httplib::Request& request, httplib::Response& response)
         syslog(LOG_ERR, "access reject in add user request");
         return;
     }
-
-    std::ifstream usersfile(USERS_FILE);
-    nlohmann::json all_users = nlohmann::json::parse(usersfile);
-    usersfile.close();
+    nlohmann::json all_users;
+    {
+        std::lock_guard<std::mutex> lock(usersfilemutex);
+        std::ifstream usersfile(USERS_FILE);
+        all_users = nlohmann::json::parse(usersfile);
+        usersfile.close();
+    }
 
     nlohmann::json response_user_data = nullptr;
     for (nlohmann::json& user : all_users) {
@@ -102,6 +105,7 @@ void add_user(const httplib::Request& request, httplib::Response& response)
     new_user_data += "}";
     all_users.push_back(nlohmann::json::parse(new_user_data));
 
+    std::lock_guard<std::mutex> lock(usersfilemutex);
     std::ofstream usersfilew(USERS_FILE);
     usersfilew << all_users.dump(4);
     usersfilew.close();