set identifying environment variable for new connections

src/cascadia/TerminalConnection/ConhostConnection.cpp

@@ -12,27 +12,32 @@
 #endif
 
 #include <conpty-universal.h>
+#include "../../types/inc/Utils.hpp"
+
+using namespace ::Microsoft::Console;
 
 namespace winrt::Microsoft::Terminal::TerminalConnection::implementation
 {
-    ConhostConnection::ConhostConnection(hstring const& commandline,
-                                         hstring const& startingDirectory,
-                                        uint32_t initialRows,
-                                        uint32_t initialCols) :
-        _connected{ false },
-        _inPipe{ INVALID_HANDLE_VALUE },
-        _outPipe{ INVALID_HANDLE_VALUE },
-        _signalPipe{ INVALID_HANDLE_VALUE },
-        _outputThreadId{ 0 },
-        _hOutputThread{ INVALID_HANDLE_VALUE },
-        _piConhost{ 0 },
-        _closing{ false }
+    ConhostConnection::ConhostConnection(const hstring& commandline,
+                                         const hstring& startingDirectory,
+                                         const uint32_t initialRows,
+                                         const uint32_t initialCols,
+                                         const guid& initialGuid) :
+        _initialRows{ initialRows },
+        _initialCols{ initialCols },
+        _commandline{ commandline },
+        _startingDirectory{ startingDirectory },
+        _guid{ initialGuid }
     {
-        _commandline = commandline;
-        _startingDirectory = startingDirectory;
-        _initialRows = initialRows;
-        _initialCols = initialCols;
+        if (_guid == guid())
+        {
+            _guid = Utils::CreateGuid();
+        }
+    }
 
+    winrt::guid ConhostConnection::Guid() const noexcept
+    {
+        return _guid;
     }
 
     winrt::event_token ConhostConnection::TerminalOutput(Microsoft::Terminal::TerminalConnection::TerminalOutputEventArgs const& handler)
@@ -57,27 +62,41 @@ namespace winrt::Microsoft::Terminal::TerminalConnection::implementation
 
     void ConhostConnection::Start()
     {
-        std::wstring cmdline = _commandline.c_str();
+        std::wstring cmdline{ _commandline.c_str() };
         std::optional<std::wstring> startingDirectory;
         if (!_startingDirectory.empty())
         {
             startingDirectory = _startingDirectory;
         }
 
-        CreateConPty(cmdline,
-                     startingDirectory,
-                     static_cast<short>(_initialCols),
-                     static_cast<short>(_initialRows),
-                     &_inPipe,
-                     &_outPipe,
-                     &_signalPipe,
-                     &_piConhost);
+        EnvironmentVariableMapW extraEnvVars;
+        {
+            // Convert connection Guid to string and ignore the enclosing '{}'.
+            std::wstring wsGuid{ Utils::GuidToString(_guid) };
+            wsGuid.pop_back();
+
+            const wchar_t* const pwszGuid{ wsGuid.data() + 1 };
+
+            // Ensure every connection has the unique identifier in the environment.
+            extraEnvVars.emplace(L"WT_SESSION", pwszGuid);
+        }
+
+        THROW_IF_FAILED(
+            CreateConPty(cmdline,
+                         startingDirectory,
+                         static_cast<short>(_initialCols),
+                         static_cast<short>(_initialRows),
+                         &_inPipe,
+                         &_outPipe,
+                         &_signalPipe,
+                         &_piConhost,
+                         extraEnvVars));
 
         _connected = true;
 
         // Create our own output handling thread
         // Each console needs to make sure to drain the output from its backing host.
-        _outputThreadId = (DWORD)-1;
+        _outputThreadId = static_cast<DWORD>(-1);
         _hOutputThread = CreateThread(nullptr,
                                       0,
                                       StaticOutputThreadProc,

src/cascadia/TerminalConnection/ConhostConnection.h

@@ -9,7 +9,7 @@ namespace winrt::Microsoft::Terminal::TerminalConnection::implementation
 {
     struct ConhostConnection : ConhostConnectionT<ConhostConnection>
     {
-        ConhostConnection(const hstring& cmdline, const hstring& startingDirectory, uint32_t rows, uint32_t cols);
+        ConhostConnection(const hstring& cmdline, const hstring& startingDirectory, const uint32_t rows, const uint32_t cols, const guid& guid);
 
         winrt::event_token TerminalOutput(TerminalConnection::TerminalOutputEventArgs const& handler);
         void TerminalOutput(winrt::event_token const& token) noexcept;
@@ -20,24 +20,26 @@ namespace winrt::Microsoft::Terminal::TerminalConnection::implementation
         void Resize(uint32_t rows, uint32_t columns);
         void Close();
 
+        winrt::guid Guid() const noexcept;
+
     private:
         winrt::event<TerminalConnection::TerminalOutputEventArgs> _outputHandlers;
         winrt::event<TerminalConnection::TerminalDisconnectedEventArgs> _disconnectHandlers;
 
-        uint32_t _initialRows;
-        uint32_t _initialCols;
-        hstring _commandline;
-        hstring _startingDirectory;
-
-        bool _connected;
-        HANDLE _inPipe;  // The pipe for writing input to
-        HANDLE _outPipe; // The pipe for reading output from
-        HANDLE _signalPipe;
-        //HPCON _hPC;
-        DWORD _outputThreadId;
-        HANDLE _hOutputThread;
-        PROCESS_INFORMATION _piConhost;
-        bool _closing;
+        uint32_t _initialRows{};
+        uint32_t _initialCols{};
+        hstring _commandline{};
+        hstring _startingDirectory{};
+
+        bool _connected{};
+        HANDLE _inPipe{ INVALID_HANDLE_VALUE };  // The pipe for writing input to
+        HANDLE _outPipe{ INVALID_HANDLE_VALUE }; // The pipe for reading output from
+        HANDLE _signalPipe{ INVALID_HANDLE_VALUE };
+        DWORD _outputThreadId{};
+        HANDLE _hOutputThread{ INVALID_HANDLE_VALUE };
+        PROCESS_INFORMATION _piConhost{};
+        guid _guid{}; // A "unique" session identifier for connected client
+        bool _closing{};
 
         static DWORD WINAPI StaticOutputThreadProc(LPVOID lpParameter);
         DWORD _OutputThread();

src/cascadia/TerminalConnection/ConhostConnection.idl

@@ -8,7 +8,9 @@ namespace Microsoft.Terminal.TerminalConnection
     [default_interface]
     runtimeclass ConhostConnection : ITerminalConnection
     {
-        ConhostConnection(String cmdline, String startingDirectory, UInt32 rows, UInt32 columns);
+        ConhostConnection(String cmdline, String startingDirectory, UInt32 rows, UInt32 columns, Guid guid);
+
+        Guid Guid { get; };
     };
 
 }

src/cascadia/TerminalConnection/TerminalConnection.vcxproj

@@ -52,6 +52,18 @@
 
   </ItemDefinitionGroup>
 
+  <!-- ========================= Project References ======================== -->
+  <ItemGroup>
+    <!--
+      the packaging project won't recurse through our dependencies, you have to
+      make sure that if you add a cppwinrt dependency to any of these projects,
+      you also update all the consumers
+    -->
+    <ProjectReference Include="$(OpenConsoleDir)src\types\lib\types.vcxproj">
+      <Project>{18D09A24-8240-42D6-8CB6-236EEE820263}</Project>
+    </ProjectReference>
+
+  </ItemGroup>
   <PropertyGroup>
     <!--
       DON'T REDIRECT OUR OUTPUT.

src/cascadia/TerminalConnection/pch.h

@@ -7,5 +7,11 @@
 
 #pragma once
 
+#include <LibraryIncludes.h>
+
+// Must be included before any WinRT headers.
+#include <unknwn.h>
+
 #include "winrt/Windows.Foundation.h"
 #include <Windows.h>
+#include <wil/result.h>

src/cascadia/TerminalControl/TermControl.cpp

@@ -26,7 +26,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
     }
 
     TermControl::TermControl(Settings::IControlSettings settings) :
-        _connection{ TerminalConnection::ConhostConnection(winrt::to_hstring("cmd.exe"), winrt::hstring(), 30, 80) },
+        _connection{ TerminalConnection::ConhostConnection(winrt::to_hstring("cmd.exe"), winrt::hstring(), 30, 80, winrt::guid()) },
         _initializedTerminal{ false },
         _root{ nullptr },
         _controlRoot{ nullptr },
@@ -221,7 +221,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
     //     directory.
     void TermControl::_ApplyConnectionSettings()
     {
-        _connection = TerminalConnection::ConhostConnection(_settings.Commandline(), _settings.StartingDirectory(), 30, 80);
+        _connection = TerminalConnection::ConhostConnection(_settings.Commandline(), _settings.StartingDirectory(), 30, 80, winrt::guid());
     }
 
     TermControl::~TermControl()