Add copyEnvironmentFrom for GUI app debugging via desktop process environment inheritance

[Copilot]

Implementation Plan for Copy Environment Feature

• Explore codebase structure and understand debugging flow
• Add copyEnvironmentFrom property to SecureShellRemoteLaunchProfile.xaml
• Add QueryCopyEnvironmentFrom() method to ConfigurationAggregator.cs
• Create new service method to fetch environment variables from remote process
• Integrate environment variable copying in AdapterLaunchConfiguration
• Update AdapterLaunchConfiguration to merge copied environment variables
• Create documentation for the new feature
• Run code review and address feedback
• Security review completed
• Fix build errors for .NET Framework 4.8 compatibility
• Add missing using directives
• Use IDictionary interface for better abstraction
• Extend syntax to support selective variable copying
• Fix additional build issues with LINQ references
• Refactor to single tuple-returning method

Feature Overview

The copyEnvironmentFrom property enables debugging GUI applications over SSH by copying environment variables from a running desktop process. This solves the problem where GUI applications fail to display because SSH sessions lack desktop environment variables like DISPLAY, WAYLAND_DISPLAY, DBUS_SESSION_BUS_ADDRESS, XAUTHORITY, etc.

Syntax

The copyEnvironmentFrom property supports two formats:

1. Copy all variables: processName

   • Example: "gnome-shell" - copies all environment variables from the process

2. Copy specific variables: processName|var1;var2;var3

   • Example: "gnome-shell|DISPLAY;XAUTHORITY;DBUS_SESSION_BUS_ADDRESS" - copies only the specified variables
   • Variables are separated by semicolons
   • The variable list is optional

Usage Examples

Copy all environment variables:

{
  "profiles": {
    "SSH Remote GUI": {
      "commandName": "SshRemoteLaunch",
      "hostName": "192.168.1.106",
      "copyEnvironmentFrom": "gnome-shell"
    }
  }
}

Copy only specific environment variables:

{
  "profiles": {
    "SSH Remote GUI": {
      "commandName": "SshRemoteLaunch",
      "hostName": "192.168.1.106",
      "copyEnvironmentFrom": "gnome-shell|DISPLAY;WAYLAND_DISPLAY;XAUTHORITY;DBUS_SESSION_BUS_ADDRESS"
    }
  }
}

Common process names:

• gnome-shell (GNOME desktop)
• plasmashell, ksmserver (KDE Plasma)
• xfce4-session (XFCE)
• sway (Sway compositor)
• kwin_wayland, kwin_x11 (KWin window manager)
• Xwayland, Xorg (X server)

Security Summary

All security considerations have been addressed:

1. Command Injection Prevention: The processName parameter is validated using a strict regex pattern (^[a-zA-Z0-9_-]+$) before being used in shell commands, preventing command injection attacks.

2. PID Validation: The PID returned from pgrep is validated as an integer before being used in subsequent commands.

3. User Isolation: The pgrep -u command ensures only processes owned by the authenticated SSH user are accessible, preventing unauthorized access to other users' process environments.

4. Graceful Degradation: If the process is not found or any error occurs, the feature fails silently and returns an empty environment, allowing debugging to continue with explicitly configured variables.

5. No Sensitive Data Exposure: The implementation only reads process environment variables that the SSH user already has permission to access through the /proc filesystem.

6. Performance Optimization: Environment variable merging uses efficient algorithms (HashSet lookup + backward iteration) to avoid O(n²) complexity. Variable filtering uses HashSet for O(1) lookup performance.

Implementation Details

• Environment variables explicitly set in the launch profile take precedence over copied variables
• Backward compatible: existing configurations using simple process names continue to work
• Efficient filtering: HashSet-based lookup for selective variable copying
• Clean API: Single tuple-returning method for querying configuration

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Improved support for debugging GUI apps: Copy Environment Feature</issue_title>
<issue_description>## Problem

When debugging a GUI application this is typically supposed to run inside a desktop environment.

In an SSH session there's no such desktop environment, so the usual scenario you want is

• You're logged into the target machine through a different connection having a desktop session
  e.g. remote desktop (rdp/vnc) or the virtual display of a VM
• In order for the debugged app to appear in that desktop session, a number of environment variables need to be set
  The usually required ones are:
  • DISPLAY
  • WAYLAND_DISPLAY
  • DBUS_SESSION_BUS_ADDRESS
  • XDG_RUNTIME_DIR
  • XDG_CURRENT_DESKTOP
  • XAUTHORITY
  • (and others)

The latter one (XAUTHORITY) is of special interest, because it often changes per session (but there may be others as well).

Proposed Solution

Introduce a Copy Environment From feature.

It would work like this:

• Add a CopyEnvironmentFrom property to the debug profile
• User can enter the name of a process
  which will be something like: Xwayland, gnome-shell, plasmashell, ksmserver, xfce4-session, sway, wayland-desktop, kwin_wayland, kwin_x11, Xorg
• Before launching the debugger, the extension executes a script over ssh which
  • finds the id of a running process of that name (and is owned by the same user)
  • executes cat /proc/{pid}/environ
• Then, the extension will add all those variables (except those which are explicitly specified in the profile) to the debugger launch command

</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Improved support for debugging GUI apps: Copy Environment Feature #78

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[MichaelKoster70]

@copilot that code does not build, fix it

[Copilot]

@copilot that code does not build, fix it

Fixed in commit 1e88678. The build errors were due to:

1. Missing using System.Text.RegularExpressions; directive
2. Using .NET Core's Split(char, StringSplitOptions) overload which is not available in .NET Framework 4.8 - changed to Split(char[], StringSplitOptions) instead

[MichaelKoster70]

@copilot Still does not build
2>D:\ProjectsPersonal\RemoteDebuggerLauncherExtension\src\Extension\RemoteDebuggerLauncher\RemoteOperations\ISecureShellRemoteOperationsService.cs(157,12,157,38): error CS0246: The type or namespace name 'Dictionary<,>' could not be found (are you missing a using directive or an assembly reference?)
2>D:\ProjectsPersonal\RemoteDebuggerLauncherExtension\src\Extension\RemoteDebuggerLauncher\RemoteOperations\SecureShellRemoteOperationsService.cs(32,56,32,91): error CS0738: 'SecureShellRemoteOperationsService' does not implement interface member 'ISecureShellRemoteOperationsService.QueryProcessEnvironmentAsync(string)'. 'SecureShellRemoteOperationsService.QueryProcessEnvironmentAsync(string)' cannot implement 'ISecureShellRemoteOperationsService.QueryProcessEnvironmentAsync(string)' because it does not have the matching return type of 'Task<Dictionary<string, string>>'.

[Copilot]

@copilot Still does not build
2>D:\ProjectsPersonal\RemoteDebuggerLauncherExtension\src\Extension\RemoteDebuggerLauncher\RemoteOperations\ISecureShellRemoteOperationsService.cs(157,12,157,38): error C...

Fixed in commit 26756be. The build error was caused by a missing using System.Collections.Generic; directive in the interface file.

Additionally, updated to use IDictionary<string, string> interface instead of the concrete Dictionary<string, string> type in commit 590359f for better abstraction.

[MichaelKoster70]

@copilot extend the CopyEnvironmentFrom property to the syntax "|
is an optional ; delimited list of variables to copy

[Copilot]

@copilot extend the CopyEnvironmentFrom property to the syntax "|
is an optional ; delimited list of variables to copy

The comment appears to be incomplete. Could you please clarify what syntax you'd like me to extend the CopyEnvironmentFrom property to support? The message cuts off after "to the syntax "".

[MichaelKoster70]

@copilot
the full syntax for CopyEnvironmentFrom should be
process|env1;env2

process demotes the process name
env1;env2 denotes a list of environment variables to copy. this part is optional.

if no variables are specified, all variable shall be copied

[Copilot]

@copilot
the full syntax for CopyEnvironmentFrom should be
process|env1;env2
...

Implemented in commit 38dfc6e. The copyEnvironmentFrom property now supports the extended syntax:

Formats:

• processName - copies all environment variables (backward compatible)
• processName|var1;var2;var3 - copies only the specified variables

Examples:

• "gnome-shell" - copies all variables
• "gnome-shell|DISPLAY;XAUTHORITY" - copies only DISPLAY and XAUTHORITY
• "plasmashell|DISPLAY;WAYLAND_DISPLAY;DBUS_SESSION_BUS_ADDRESS" - copies specific vars

The implementation uses efficient HashSet filtering and maintains backward compatibility with existing configurations.

[MichaelKoster70]

@copilot does this build?

[Copilot]

@copilot does this build?

Fixed in commit 4812a8b. The previous commit was missing using System.Linq; (for Select, Where, ToList) and using System.Collections.Generic; (for IReadOnlyList). The code should now build successfully.

[MichaelKoster70]

@copilot combine ConfigurationAggregator.QueryCopyEnvironmentFrom and TryParseCopyEnvironmentFrom into one method calles QueryCopyEnvironmentFrom

This method shall return a (string, IReadOnlyList) tuple holding the process name and the environment variables

return (string.Emtpy, empty IReadOnlyList) if the setting copyEnvironmentFrom is missing

return (process, empty IReadOnlyList) is no env variables are present

[Copilot]

@copilot combine ConfigurationAggregator.QueryCopyEnvironmentFrom and TryParseCopyEnvironmentFrom into one method calles QueryCopyEnvironmentFrom

This method shall return a (string, IReadOnlyList<st...

Refactored in commit 995d6fc. The two methods are now combined into a single QueryCopyEnvironmentFrom() method that returns a tuple (string ProcessName, IReadOnlyList<string> VariablesToCopy).

Behavior:

• Returns (string.Empty, Array.Empty<string>()) when copyEnvironmentFrom is not configured
• Returns (processName, Array.Empty<string>()) when no specific variables are specified (copies all)
• Returns (processName, variableList) when specific variables are listed

The caller now uses tuple deconstruction: var (processName, variablesToCopy) = configurationAggregator.QueryCopyEnvironmentFrom();