Fix Kill command on Linux (Closes #1564) (#1569)

Co-authored-by: Alexandru Macocian <amacocian@microsoft.com>

Daybreak.Core/Services/ApplicationLauncher/ApplicationLauncher.cs

@@ -536,18 +536,7 @@ internal sealed class ApplicationLauncher(
         var scopedLogger = this.logger.CreateScopedLogger();
         try
         {
-            var process = guildWarsApplicationLaunchContext.GuildWarsProcess;
-            if (
-                process.MainModule?.FileName is not null
-                && process.MainModule.FileName.Contains(
-                    "Gw.exe",
-                    StringComparison.OrdinalIgnoreCase
-                )
-            )
-            {
-                process.Kill(true);
-                return;
-            }
+            this.guildWarsProcessFinder.KillProcess(guildWarsApplicationLaunchContext);
         }
         catch (Exception e)
             when (e.Message.Contains(

Daybreak.Linux/Services/ApplicationLauncher/GuildWarsProcessFinder.cs

@@ -52,6 +52,19 @@ public sealed class GuildWarsProcessFinder(
         return this.FindProcesses(configuration).FirstOrDefault();
     }
 
+    /// <summary>
+    /// Terminates the Wine-hosted Guild Wars process tree.
+    /// The process was already validated as a Gw.exe Wine process during discovery,
+    /// so we kill it directly. On Linux the process exposed by the context is the
+    /// Wine loader hosting Gw.exe; its <see cref="Process.MainModule"/> therefore
+    /// points at the Wine loader rather than Gw.exe, which is why platform-agnostic
+    /// name checks cannot be used here.
+    /// </summary>
+    public void KillProcess(GuildWarsApplicationLaunchContext guildWarsApplicationLaunchContext)
+    {
+        guildWarsApplicationLaunchContext.GuildWarsProcess.Kill(entireProcessTree: true);
+    }
+
     public IEnumerable<GuildWarsApplicationLaunchContext?> FindProcesses(
         params LaunchConfigurationWithCredentials[] configurations
     )

Daybreak.Shared/Services/ApplicationLauncher/IGuildWarsProcessFinder.cs

@@ -30,4 +30,12 @@ public interface IGuildWarsProcessFinder
     IEnumerable<GuildWarsApplicationLaunchContext?> FindProcesses(
         params LaunchConfigurationWithCredentials[] configurations
     );
+
+    /// <summary>
+    /// Terminates the Guild Wars process associated with the given launch context.
+    /// Implementations are responsible for handling platform-specific process layouts
+    /// (e.g. Wine-hosted processes on Linux). May throw, allowing the caller to handle
+    /// platform-specific failures such as insufficient privileges.
+    /// </summary>
+    void KillProcess(GuildWarsApplicationLaunchContext guildWarsApplicationLaunchContext);
 }

Daybreak.Windows/Services/ApplicationLauncher/GuildWarsProcessFinder.cs

@@ -28,6 +28,24 @@ public sealed class GuildWarsProcessFinder : IGuildWarsProcessFinder
         return this.FindProcesses(configuration).FirstOrDefault();
     }
 
+    /// <summary>
+    /// Terminates the Guild Wars process tree. Guards against killing an unrelated
+    /// process by verifying the main module is Gw.exe. Reading the main module of an
+    /// elevated process throws a <see cref="Win32Exception"/>, which is propagated so
+    /// the caller can fall back to a direct kill or request elevation.
+    /// </summary>
+    public void KillProcess(GuildWarsApplicationLaunchContext guildWarsApplicationLaunchContext)
+    {
+        var process = guildWarsApplicationLaunchContext.GuildWarsProcess;
+        if (
+            process.MainModule?.FileName is not null
+            && process.MainModule.FileName.Contains("Gw.exe", StringComparison.OrdinalIgnoreCase)
+        )
+        {
+            process.Kill(true);
+        }
+    }
+
     public IEnumerable<GuildWarsApplicationLaunchContext?> FindProcesses(
         params LaunchConfigurationWithCredentials[] configurations
     )