Let's rebuild from the ground up.

Overhauls DreamDaemonExecutor and adds DreamDaemonSession

src/Tgstation.Server.Host.Service/Program.cs

@@ -60,7 +60,7 @@ namespace Tgstation.Server.Host.Service
 					UseShellExecute = true,
 					Verb = "runas",
 					Arguments = String.Join(" ", argList),
-					FileName = Assembly.GetExecutingAssembly().Location,
+					FileName = exe,
 					WorkingDirectory = Environment.CurrentDirectory,
 				};
 				using (Process.Start(startInfo))

src/Tgstation.Server.Host/Components/DreamDaemonExecutor.cs

@@ -1,14 +1,8 @@
-using Newtonsoft.Json;
-using System;
+using System;
 using System.Diagnostics;
 using System.Globalization;
-using System.Text;
-using System.Threading;
-using System.Threading.Tasks;
 using Tgstation.Server.Api.Models;
 using Tgstation.Server.Api.Models.Internal;
-using Tgstation.Server.Host.Components.Models;
-using Tgstation.Server.Host.Core;
 
 namespace Tgstation.Server.Host.Components
 {
@@ -35,34 +29,11 @@ namespace Tgstation.Server.Host.Components
 			}
 		}
 
-		/// <summary>
-		/// The <see cref="IInstanceShutdownHandler"/> for the <see cref="DreamDaemonExecutor"/>
-		/// </summary>
-		readonly IInstanceShutdownHandler instanceShutdownMethod;
-		/// <summary>
-		/// The <see cref="IIOManager"/> for the <see cref="DreamDaemonExecutor"/>
-		/// </summary>
-		readonly IIOManager ioManager;
-		/// <summary>
-		/// The <see cref="IApplication"/> for the <see cref="DreamDaemonExecutor"/>
-		/// </summary>
-		readonly IApplication application;
-
-		/// <summary>
-		/// Construct a <see cref="DreamDaemonExecutor"/>
-		/// </summary>
-		/// <param name="instanceShutdownMethod">The value of <see cref="instanceShutdownMethod"/></param>
-		/// <param name="ioManager">The value of <see cref="ioManager"/></param>
-		/// <param name="application">The value of <see cref="application"/></param>
-		public DreamDaemonExecutor(IInstanceShutdownHandler instanceShutdownMethod, IIOManager ioManager, IApplication application)
-		{
-			this.instanceShutdownMethod = instanceShutdownMethod ?? throw new ArgumentNullException(nameof(instanceShutdownMethod));
-			this.ioManager = ioManager ?? throw new ArgumentNullException(nameof(ioManager));
-			this.application = application ?? throw new ArgumentNullException(nameof(application));
-		}
+		/// <inheritdoc />
+		public IDreamDaemonSession AttachToDreamDaemon(int processId) => new DreamDaemonSession(Process.GetProcessById(processId));
 
 		/// <inheritdoc />
-		public async Task<int> RunDreamDaemon(DreamDaemonLaunchParameters launchParameters, TaskCompletionSource<object> onSuccessfulStartup, string dreamDaemonPath, IDmbProvider dmbProvider, InteropInfo interopInfo, bool alwaysKill, bool asDefaultOtherServer, CancellationToken cancellationToken)
+		public IDreamDaemonSession RunDreamDaemon(DreamDaemonLaunchParameters launchParameters, string dreamDaemonPath, IDmbProvider dmbProvider, string parameters, bool useSecondaryPort, bool useSecondaryDirectory)
 		{
 			if (launchParameters == null)
 				throw new ArgumentNullException(nameof(launchParameters));
@@ -70,69 +41,32 @@ namespace Tgstation.Server.Host.Components
 				throw new ArgumentNullException(nameof(dreamDaemonPath));
 			if (dmbProvider == null)
 				throw new ArgumentNullException(nameof(dmbProvider));
-			if (interopInfo == null)
-				throw new ArgumentNullException(nameof(interopInfo));
+			if (parameters == null)
+				throw new ArgumentNullException(nameof(parameters));
 
-			if (interopInfo.NextPort != launchParameters.PrimaryPort && interopInfo.NextPort != launchParameters.SecondaryPort)
-				throw new ArgumentOutOfRangeException(nameof(interopInfo), interopInfo, "interopInfo.NextPort must match primary or secondary ports!");
+			var proc = new Process();
 
-			var isPrimary = interopInfo.NextPort == launchParameters.SecondaryPort;
-
-			//serialize the interop info to the json
-			var jsonPath = String.Concat(Guid.NewGuid(), ".tgs.json");
-
-			var json = JsonConvert.SerializeObject(interopInfo);
-
-
-			using (var proc = new Process())
+			try
 			{
 				proc.StartInfo.FileName = dreamDaemonPath;
-				proc.StartInfo.WorkingDirectory = isPrimary ? dmbProvider.PrimaryDirectory : dmbProvider.SecondaryDirectory;
-				await ioManager.WriteAllBytes(ioManager.ConcatPath(proc.StartInfo.WorkingDirectory, jsonPath), Encoding.UTF8.GetBytes(json), cancellationToken).ConfigureAwait(false);
+				proc.StartInfo.WorkingDirectory = useSecondaryDirectory ? dmbProvider.SecondaryDirectory : dmbProvider.PrimaryDirectory;
 
-				proc.StartInfo.Arguments = String.Format(CultureInfo.InvariantCulture, "{0} -port {1} {2}-close -{3} -verbose -public -params \"{4}={5}&{6}={7}\"", 
+				proc.StartInfo.Arguments = String.Format(CultureInfo.InvariantCulture, "{0} -port {1} {2}-close -{3} -verbose -public -params \"{4}\"",
 					dmbProvider.DmbName,
-					isPrimary && !asDefaultOtherServer ? launchParameters.PrimaryPort : launchParameters.SecondaryPort,
+					useSecondaryPort ? launchParameters.SecondaryPort : launchParameters.PrimaryPort,
 					launchParameters.AllowWebClient.Value ? "-webclient " : String.Empty,
 					SecurityWord(launchParameters.SecurityLevel.Value),
-					DreamDaemonParameters.HostVersion, Application.Version,
-					DreamDaemonParameters.InfoJsonPath, jsonPath);
+					parameters);
 
-				proc.EnableRaisingEvents = true;
-				var tcs = new TaskCompletionSource<object>();
-				proc.Exited += (a, b) => tcs.SetResult(null);
+				proc.Start();
 
-				try
-				{
-					proc.Start();
-
-					await Task.Factory.StartNew(() => proc.WaitForInputIdle(), cancellationToken, TaskCreationOptions.LongRunning, TaskScheduler.Current).ConfigureAwait(false);
-
-					onSuccessfulStartup?.SetResult(null);
-
-					try
-					{
-						using (cancellationToken.Register(() => tcs.SetCanceled()))
-							await tcs.Task.ConfigureAwait(false);
-					}
-					finally
-					{
-						if (!alwaysKill && !await instanceShutdownMethod.PreserveActiveExecutablesIfNecessary(launchParameters, interopInfo.AccessToken, proc.Id, isPrimary).ConfigureAwait(false))
-						{
-							proc.Kill();
-							proc.WaitForExit();
-						}
-					}
-
-					return proc.ExitCode;
-				}
-				catch (Exception e)
-				{
-					onSuccessfulStartup?.SetException(e);
-					throw;
-				}
+				return new DreamDaemonSession(proc);
+			}
+			catch
+			{
+				proc.Dispose();
+				throw;
 			}
 		}
-
 	}
 }

src/Tgstation.Server.Host/Components/DreamDaemonSession.cs

@@ -0,0 +1,56 @@
+using System;
+using System.Diagnostics;
+using System.Threading.Tasks;
+
+namespace Tgstation.Server.Host.Components
+{
+	/// <inheritdoc />
+	sealed class DreamDaemonSession : IDreamDaemonSession
+	{
+		/// <inheritdoc />
+		public int ProcessId => process.Id;
+
+		/// <inheritdoc />
+		public Task SuccessfulStartup { get; }
+
+		/// <inheritdoc />
+		public Task<int> Lifetime => lifetimeTask.Task;
+
+		/// <summary>
+		/// The actual <see cref="Process"/>
+		/// </summary>
+		readonly Process process;
+		/// <summary>
+		/// The backing <see cref="TaskCompletionSource{TResult}"/> for <see cref="Lifetime"/>
+		/// </summary>
+		readonly TaskCompletionSource<int> lifetimeTask;
+
+		/// <summary>
+		/// Construct a <see cref="DreamDaemonSession"/>
+		/// </summary>
+		/// <param name="process">The value of <see cref="process"/></param>
+		public DreamDaemonSession(Process process)
+		{
+			this.process = process ?? throw new ArgumentNullException(nameof(process));
+
+			SuccessfulStartup = Task.Factory.StartNew(() => process.WaitForInputIdle(), default, TaskCreationOptions.LongRunning, TaskScheduler.Current);
+			lifetimeTask = new TaskCompletionSource<int>();
+			process.EnableRaisingEvents = true;
+			process.Exited += (a, b) => lifetimeTask.SetResult(process.ExitCode);
+		}
+
+		/// <inheritdoc />
+		public void Dispose() => process.Dispose();
+
+		/// <inheritdoc />
+		public void Terminate()
+		{
+			try
+			{
+				process.Kill();
+				process.WaitForExit();
+			}
+			catch (InvalidOperationException) { }
+		}
+	}
+}

src/Tgstation.Server.Host/Components/IDreamDaemonExecutor.cs

@@ -1,12 +1,9 @@
-using System.Threading;
-using System.Threading.Tasks;
-using Tgstation.Server.Api.Models.Internal;
-using Tgstation.Server.Host.Components.Models;
+using Tgstation.Server.Api.Models.Internal;
 
 namespace Tgstation.Server.Host.Components
 {
 	/// <summary>
-	/// For running a DreamDaemon instance
+	/// For creating <see cref="IDreamDaemonSession"/>s
 	/// </summary>
     interface IDreamDaemonExecutor
     {
@@ -17,11 +14,17 @@ namespace Tgstation.Server.Host.Components
 		/// <param name="onSuccessfulStartup">The <see cref="TaskCompletionSource{TResult}"/> that is completed when dream daemon starts without crashing</param>
 		/// <param name="dreamDaemonPath">The path to the dreamdaemon executable</param>
 		/// <param name="dmbProvider">The <see cref="IDmbProvider"/> for the .dmb to run</param>
-		/// <param name="interopInfo">The <see cref="InteropInfo"/> for the run</param>
-		/// <param name="alwaysKill">If the resulting process should never be left alive</param>
-		/// <param name="asDefaultOtherServer">If <see langword="true"/> the ports will be swapped for the launch</param>
-		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation</param>
-		/// <returns>A <see cref="Task{TResult}"/> representing the lifetime of the process and resulting in the exit code</returns>
-		Task<int> RunDreamDaemon(DreamDaemonLaunchParameters launchParameters, TaskCompletionSource<object> onSuccessfulStartup, string dreamDaemonPath, IDmbProvider dmbProvider, InteropInfo interopInfo, bool alwaysKill, bool asDefaultOtherServer, CancellationToken cancellationToken);
+		/// <param name="parameters">The value of the -params command line option</param>
+		/// <param name="useSecondaryPort">If the <see cref="DreamDaemonLaunchParameters.SecondaryPort"/> field of <paramref name="launchParameters"/> should be used</param>
+		/// <param name="useSecondaryDirectory">If the <see cref="IDmbProvider.SecondaryDirectory"/> field of <paramref name="dmbProvider"/> should be used</param>
+		/// <returns>A new <see cref="IDreamDaemonSession"/></returns>
+		IDreamDaemonSession RunDreamDaemon(DreamDaemonLaunchParameters launchParameters, string dreamDaemonPath, IDmbProvider dmbProvider, string parameters, bool useSecondaryPort, bool useSecondaryDirectory);
+
+		/// <summary>
+		/// Attach to a running instance of DreamDaemon
+		/// </summary>
+		/// <param name="processId">The <see cref="IDreamDaemonSession.ProcessId"/></param>
+		/// <returns>A new <see cref="IDreamDaemonSession"/></returns>
+		IDreamDaemonSession AttachToDreamDaemon(int processId);
 	}
 }

src/Tgstation.Server.Host/Components/IDreamDaemonSession.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Threading.Tasks;
+
+namespace Tgstation.Server.Host.Components
+{
+	/// <summary>
+	/// Represents a dream daemon process
+	/// </summary>
+	interface IDreamDaemonSession : IDisposable
+	{
+		/// <summary>
+		/// The <see cref="System.Diagnostics.Process.Id"/>
+		/// </summary>
+		int ProcessId { get; }
+
+		/// <summary>
+		/// A <see cref="Task"/> that completes when DreamDaemon starts pumping the windows message queue after loading a .dmb
+		/// </summary>
+		Task SuccessfulStartup { get; }
+
+		/// <summary>
+		/// A <see cref="Task"/> representing the lifetime of the <see cref="System.Diagnostics.Process"/> and resulting in the <see cref="System.Diagnostics.Process.ExitCode"/>
+		/// </summary>
+		Task<int> Lifetime { get; }
+
+		/// <summary>
+		/// Terminates the running process
+		/// </summary>
+		void Terminate();
+	}
+}

src/Tgstation.Server.Host/Controllers/ModelController.cs

@@ -59,7 +59,7 @@ namespace Tgstation.Server.Host.Controllers
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation</param>
 		/// <returns>A <see cref="Task{TResult}"/> resulting in the <see cref="IActionResult"/> of the operation</returns>
 		[HttpPost]
-		public virtual Task<IActionResult> UpdateAsync([FromBody]TModel model, CancellationToken cancellationToken) => Task.FromResult((IActionResult)NotFound());
+		public virtual Task<IActionResult> Update([FromBody]TModel model, CancellationToken cancellationToken) => Task.FromResult((IActionResult)NotFound());
 
 		/// <summary>
 		/// Attempt to delete a <paramref name="model"/>