fixes #22 - do not echo two-factor authentication password

CMakeLists.txt

@@ -1,6 +1,6 @@
 # Project
 cmake_minimum_required(VERSION 3.1 FATAL_ERROR)
-project(nchat VERSION 0.25 LANGUAGES CXX)
+project(nchat VERSION 0.26 LANGUAGES CXX)
 set(CMAKE_CXX_STANDARD 14)
 
 # Paths

src/nchat.1

@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man 1.47.8.
-.TH NCHAT "1" "November 2019" "nchat v0.25" "User Commands"
+.TH NCHAT "1" "February 2020" "nchat v0.26" "User Commands"
 .SH NAME
 nchat \- ncurses chat
 .SH SYNOPSIS

src/telegram.cpp

@@ -569,8 +569,7 @@ void Telegram::OnAuthStateUpdate()
       if (m_IsSetup)
       {
         std::cout << "Enter authentication password: ";
-        std::string password;
-        std::getline(std::cin, password);
+        std::string password = Util::GetPass();
         SendQuery(td::td_api::make_object<td::td_api::checkAuthenticationPassword>(password),
                   CreateAuthQueryHandler());
       }

src/util.cpp

@@ -9,6 +9,7 @@
 
 #include <algorithm>
 #include <cstdlib>
+#include <cstring>
 #include <iomanip>
 #include <iostream>
 #include <map>
@@ -530,3 +531,23 @@ void Util::CleanupStdErrRedirect()
     close(m_OrgStdErr);
   }
 }
+
+std::string Util::GetPass()
+{
+  std::string pass;
+  struct termios told, tnew;
+
+  if (tcgetattr(STDIN_FILENO, &told) == 0)
+  {
+    memcpy(&tnew, &told, sizeof(struct termios));
+    tnew.c_lflag &= ~ECHO;
+    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &tnew) == 0)
+    {
+      std::getline(std::cin, pass);
+      tcsetattr(STDIN_FILENO, TCSAFLUSH, &told);
+      std::cout << std::endl;
+    }
+  }
+
+  return pass;
+}

src/util.h

@@ -34,6 +34,7 @@ class Util
   static std::string BacktraceSymbolsStr(void* p_Callstack[], int p_Size);
   static void InitStdErrRedirect(const std::string& p_Path);
   static void CleanupStdErrRedirect();
+  static std::string GetPass();
 
 private:
   static std::string m_ConfigDir;