Implement minidumps on Windows

src/Tgstation.Server.Api/Models/DreamDaemon.cs

@@ -48,5 +48,10 @@ namespace Tgstation.Server.Api.Models
 		/// If the server is undergoing a soft shutdown
 		/// </summary>
 		public bool? SoftShutdown { get; set; }
+
+		/// <summary>
+		/// If a dump of the active DreamDaemon executable should be created.
+		/// </summary>
+		public bool? CreateDump { get; set; }
 	}
 }

src/Tgstation.Server.Api/Rights/DreamDaemonRights.cs

@@ -77,5 +77,10 @@ namespace Tgstation.Server.Api.Rights
 		/// User can change <see cref="Models.Internal.DreamDaemonLaunchParameters.HeartbeatSeconds"/>
 		/// </summary>
 		SetHeartbeatInterval = 4096,
+
+		/// <summary>
+		/// User can create DreamDaemon process dumps.
+		/// </summary>
+		CreateDump = 8192,
 	}
 }

src/Tgstation.Server.Api/Routes.cs

@@ -43,6 +43,11 @@ namespace Tgstation.Server.Api
 		/// </summary>
 		public const string DreamDaemon = Root + nameof(Models.DreamDaemon);
 
+		/// <summary>
+		/// For accessing DD diagnostics
+		/// </summary>
+		public const string Diagnostics = DreamDaemon + "/Diagnostics";
+
 		/// <summary>
 		/// The <see cref="Models.ConfigurationFile"/> controller
 		/// </summary>

src/Tgstation.Server.Host/Components/Session/DeadSessionController.cs

@@ -123,5 +123,8 @@ namespace Tgstation.Server.Host.Components.Session
 
 		/// <inheritdoc />
 		public Task InstanceRenamed(string newInstanceName, CancellationToken cancellationToken) => Task.CompletedTask;
+
+		/// <inheritdoc />
+		public Task CreateDump(string outputFile, CancellationToken cancellationToken) => throw new NotSupportedException();
 	}
 }

src/Tgstation.Server.Host/Components/Session/SessionController.cs

@@ -696,5 +696,8 @@ namespace Tgstation.Server.Host.Components.Session
 				new TopicParameters(
 					new ChatUpdate(newChannels)),
 				cancellationToken);
+
+		/// <inheritdoc />
+		public Task CreateDump(string outputFile, CancellationToken cancellationToken) => process.CreateDump(outputFile, cancellationToken);
 	}
 }

src/Tgstation.Server.Host/Components/Watchdog/IWatchdog.cs

@@ -80,5 +80,12 @@ namespace Tgstation.Server.Host.Components.Watchdog
 		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation</param>
 		/// <returns>A <see cref="Task"/> representing the running operation</returns>
 		Task ResetRebootState(CancellationToken cancellationToken);
+
+		/// <summary>
+		/// Attempt to create a process dump for DreamDaemon.
+		/// </summary>
+		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
+		/// <returns>A <see cref="Task"/> representing the running operation.</returns>
+		Task CreateDump(CancellationToken cancellationToken);
 	}
 }

src/Tgstation.Server.Host/Components/Watchdog/WatchdogBase.cs

@@ -18,6 +18,7 @@ using Tgstation.Server.Host.Components.Session;
 using Tgstation.Server.Host.Core;
 using Tgstation.Server.Host.Database;
 using Tgstation.Server.Host.Extensions;
+using Tgstation.Server.Host.IO;
 using Tgstation.Server.Host.Jobs;
 
 namespace Tgstation.Server.Host.Components.Watchdog
@@ -114,6 +115,11 @@ namespace Tgstation.Server.Host.Components.Watchdog
 		/// </summary>
 		readonly IRestartRegistration restartRegistration;
 
+		/// <summary>
+		/// The <see cref="IIOManager"/> pointing to the Diagnostics directory.
+		/// </summary>
+		readonly IIOManager diagnosticsIOManager;
+
 		/// <summary>
 		/// <see langword="lock"/> <see cref="object"/> used for <see cref="DisposeAndNullControllers"/>.
 		/// </summary>
@@ -919,5 +925,22 @@ namespace Tgstation.Server.Host.Components.Watchdog
 
 		/// <inheritdoc />
 		public abstract Task InstanceRenamed(string newInstanceName, CancellationToken cancellationToken);
+
+		/// <inheritdoc />
+		public async Task CreateDump(CancellationToken cancellationToken)
+		{
+			var session = GetActiveController();
+
+			const string DumpDirectory = "ProcessDumps";
+			await diagnosticsIOManager.CreateDirectory(DumpDirectory, cancellationToken).ConfigureAwait(false);
+
+			var dumpFileName = diagnosticsIOManager.ResolvePath(
+				diagnosticsIOManager.ConcatPath(
+					DumpDirectory,
+					$"DreamDaemon-{DateTimeOffset.Now.ToFileStamp()}.dmp"));
+
+			Logger.LogInformation("Dumping session to {0}...", dumpFileName);
+			await session.CreateDump(dumpFileName, cancellationToken).ConfigureAwait(false);
+		}
 	}
 }

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

@@ -290,5 +290,37 @@ namespace Tgstation.Server.Host.Controllers
 			await jobManager.RegisterOperation(job, (paramJob, databaseContextFactory, progressReporter, ct) => watchdog.Restart(false, ct), cancellationToken).ConfigureAwait(false);
 			return Accepted(job.ToApi());
 		}
+
+		/// <summary>
+		/// Creates a <see cref="Api.Models.Job"/> to generate a DreamDaemon process dump.
+		/// </summary>
+		/// <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 request</returns>
+		/// <response code="202">Dump <see cref="Api.Models.Job"/> started successfully.</response>
+		[HttpPost(Routes.Diagnostics)]
+		[TgsAuthorize(DreamDaemonRights.CreateDump)]
+		[ProducesResponseType(typeof(Api.Models.Job), 202)]
+		public async Task<IActionResult> CreateDump(CancellationToken cancellationToken)
+		{
+			var job = new Models.Job
+			{
+				Instance = Instance,
+				CancelRightsType = RightsType.DreamDaemon,
+				CancelRight = (ulong)DreamDaemonRights.CreateDump,
+				StartedBy = AuthenticationContext.User,
+				Description = "Create DreamDaemon Process Dump"
+			};
+
+			var watchdog = instanceManager.GetInstance(Instance).Watchdog;
+
+			if (!watchdog.Running)
+				return Conflict(new ErrorMessage(ErrorCode.WatchdogNotRunning));
+
+			await jobManager.RegisterOperation(
+				job,
+				(paramJob, databaseContextFactory, progressReporter, ct) => watchdog.CreateDump(ct), cancellationToken)
+				.ConfigureAwait(false);
+			return Accepted(job.ToApi());
+		}
 	}
 }

src/Tgstation.Server.Host/Extensions/DateTimeOffsetExtensions.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Globalization;
+
+namespace Tgstation.Server.Host.Extensions
+{
+	/// <summary>
+	/// Extension methods for the <see cref="DateTimeOffset"/> <see langword="class"/>.
+	/// </summary>
+	static class DateTimeOffsetExtensions
+	{
+		/// <summary>
+		/// Convert a given <paramref name="dateTimeOffset"/> into a <see cref="string"/> that can be used to stamp file creation times.
+		/// </summary>
+		/// <param name="dateTimeOffset">The <see cref="DateTimeOffset"/> to convert.</param>
+		/// <returns><paramref name="dateTimeOffset"/> as a file stamp <see cref="string"/>.</returns>
+		public static string ToFileStamp(this DateTimeOffset dateTimeOffset)
+			=> dateTimeOffset.ToString("yyyyMMddhhmmss", CultureInfo.InvariantCulture);
+	}
+}

src/Tgstation.Server.Host/NativeMethods.cs

@@ -5,7 +5,7 @@ using System.Text;
 namespace Tgstation.Server.Host
 {
 	/// <summary>
-	/// Native Windows methods used by the code
+	/// Native Windows methods used by the code.
 	/// </summary>
 	#pragma warning disable SA1600
 	#pragma warning disable SA1602
@@ -32,6 +32,15 @@ namespace Tgstation.Server.Host
 			SuspendResume = 0x0002,
 		}
 
+		/// <summary>
+		/// See https://docs.microsoft.com/en-us/windows/win32/api/minidumpapiset/ne-minidumpapiset-minidump_type
+		/// </summary>
+		[Flags]
+		public enum MiniDumpType : uint
+		{
+			Normal = 0x00000000
+		}
+
 		/// <summary>
 		/// See https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-getwindowthreadprocessid
 		/// </summary>
@@ -102,5 +111,18 @@ namespace Tgstation.Server.Host
 		/// </summary>
 		[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
 		public static extern uint ResumeThread(IntPtr hThread);
+
+		/// <summary>
+		/// See https://docs.microsoft.com/en-us/windows/win32/api/minidumpapiset/nf-minidumpapiset-minidumpwritedump
+		/// </summary>
+		[DllImport("dbghelp.dll", SetLastError = true, CharSet = CharSet.Unicode)]
+		public static extern bool MiniDumpWriteDump(
+			IntPtr hProcess,
+			uint processId,
+			SafeHandle hFile,
+			MiniDumpType dumpType,
+			IntPtr expParam,
+			IntPtr userStreamParam,
+			IntPtr callbackParam);
 	}
 }

src/Tgstation.Server.Host/System/IProcessBase.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace Tgstation.Server.Host.System
@@ -27,5 +28,13 @@ namespace Tgstation.Server.Host.System
 		/// Resumes the process.
 		/// </summary>
 		void Resume();
+
+		/// <summary>
+		/// Create a dump file of the process.
+		/// </summary>
+		/// <param name="outputFile">The full path to the output file.</param>
+		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
+		/// <returns>A <see cref="Task"/> representing the running operation.</returns>
+		Task CreateDump(string outputFile, CancellationToken cancellationToken);
 	}
 }

src/Tgstation.Server.Host/System/IProcessFeatures.cs

@@ -17,7 +17,7 @@ namespace Tgstation.Server.Host.System
 		Task<string> GetExecutingUsername(global::System.Diagnostics.Process process, CancellationToken cancellationToken);
 
 		/// <summary>
-		/// Suspend a given <see cref="Process"/>.
+		/// Suspend a given <paramref name="process"/>.
 		/// </summary>
 		/// <param name="process">The <see cref="Process"/> to suspend.</param>
 		void SuspendProcess(global::System.Diagnostics.Process process);
@@ -27,5 +27,14 @@ namespace Tgstation.Server.Host.System
 		/// </summary>
 		/// <param name="process">The <see cref="Process"/> to susperesumend.</param>
 		void ResumeProcess(global::System.Diagnostics.Process process);
+
+		/// <summary>
+		/// Create a dump file for a given <paramref name="process"/>.
+		/// </summary>
+		/// <param name="process">The <see cref="Process"/> to dump.</param>
+		/// <param name="outputFile">The full path to the output file.</param>
+		/// <param name="cancellationToken">The <see cref="CancellationToken"/> for the operation.</param>
+		/// <returns>A <see cref="Task"/> representing the running operation.</returns>
+		Task CreateDump(global::System.Diagnostics.Process process, string outputFile, CancellationToken cancellationToken);
 	}
 }

src/Tgstation.Server.Host/System/PosixProcessFeatures.cs

@@ -93,5 +93,11 @@ namespace Tgstation.Server.Host.System
 				.FirstOrDefault(x => !String.IsNullOrWhiteSpace(x))
 				?? "UNPARSABLE";
 		}
+
+		/// <inheritdoc />
+		public Task CreateDump(global::System.Diagnostics.Process process, string outputFile, CancellationToken cancellationToken)
+		{
+			throw new NotImplementedException();
+		}
 	}
 }

src/Tgstation.Server.Host/System/Process.cs

@@ -165,5 +165,15 @@ namespace Tgstation.Server.Host.System
 			logger.LogTrace("PID {0} Username: {1}", Id, result);
 			return result;
 		}
+
+		/// <inheritdoc />
+		public Task CreateDump(string outputFile, CancellationToken cancellationToken)
+		{
+			if (outputFile == null)
+				throw new ArgumentNullException(nameof(outputFile));
+
+			logger.LogTrace("Dumping PID {0} to {1}...", Id, outputFile);
+			return processFeatures.CreateDump(handle, outputFile, cancellationToken);
+		}
 	}
 }

src/Tgstation.Server.Host/System/WindowsProcessFeatures.cs

@@ -2,6 +2,7 @@
 using Microsoft.Extensions.Logging;
 using System;
 using System.Diagnostics;
+using System.IO;
 using System.Linq;
 using System.Management;
 using System.Threading;
@@ -110,5 +111,28 @@ namespace Tgstation.Server.Host.System
 
 			return Task.FromResult("NO OWNER");
 		}
+
+		/// <inheritdoc />
+		public async Task CreateDump(global::System.Diagnostics.Process process, string outputFile, CancellationToken cancellationToken)
+		{
+			await Task.Factory.StartNew(
+				() =>
+				{
+					using var fileStream = new FileStream(outputFile, FileMode.CreateNew);
+					if (!NativeMethods.MiniDumpWriteDump(
+						process.Handle,
+						(uint)process.Id,
+						fileStream.SafeFileHandle,
+						NativeMethods.MiniDumpType.Normal,
+						IntPtr.Zero,
+						IntPtr.Zero,
+						IntPtr.Zero))
+						throw new Win32Exception();
+				},
+				cancellationToken,
+				TaskCreationOptions.LongRunning,
+				TaskScheduler.Current)
+				.ConfigureAwait(false);
+		}
 	}
 }