Ensure child processes are cleanup up

src/WinSW.Core/Util/ProcessExtensions.cs

@@ -0,0 +1,111 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Diagnostics;
+using log4net;
+using static WinSW.Native.ProcessApis;
+
+namespace WinSW.Util
+{
+    public static class ProcessExtensions
+    {
+        private static readonly ILog Logger = LogManager.GetLogger(typeof(ProcessExtensions));
+
+        public static void StopTree(this Process process, TimeSpan stopTimeout)
+        {
+            Stop(process, stopTimeout);
+
+            foreach (Process child in GetDescendants(process))
+            {
+                StopTree(child, stopTimeout);
+            }
+        }
+
+        internal static void StopDescendants(this Process process, TimeSpan stopTimeout)
+        {
+            foreach (Process child in GetDescendants(process))
+            {
+                StopTree(child, stopTimeout);
+            }
+        }
+
+        private static void Stop(Process process, TimeSpan stopTimeout)
+        {
+            Logger.Info("Stopping process " + process.Id);
+
+            if (process.HasExited)
+            {
+                Logger.Info("Process " + process.Id + " is already stopped");
+                return;
+            }
+
+            // (bool sent, bool exited)
+            KeyValuePair<bool, bool> result = SignalHelper.SendCtrlCToProcess(process, stopTimeout);
+            bool exited = result.Value;
+            if (!exited)
+            {
+                bool sent = result.Key;
+                if (sent)
+                {
+                    Logger.Info("Process " + process.Id + " did not respond to Ctrl+C signal - Killing as fallback");
+                }
+
+                try
+                {
+                    process.Kill();
+                }
+                catch when (process.HasExited)
+                {
+                }
+            }
+
+            // TODO: Propagate error if process kill fails? Currently we use the legacy behavior
+        }
+
+        private static unsafe List<Process> GetDescendants(Process root)
+        {
+            DateTime startTime = root.StartTime;
+            int processId = root.Id;
+
+            var children = new List<Process>();
+
+            foreach (Process process in Process.GetProcesses())
+            {
+                try
+                {
+                    if (process.StartTime <= startTime)
+                    {
+                        goto Next;
+                    }
+
+                    IntPtr handle = process.Handle;
+
+                    if (NtQueryInformationProcess(
+                        handle,
+                        PROCESSINFOCLASS.ProcessBasicInformation,
+                        out PROCESS_BASIC_INFORMATION information,
+                        sizeof(PROCESS_BASIC_INFORMATION)) != 0)
+                    {
+                        goto Next;
+                    }
+
+                    if ((int)information.InheritedFromUniqueProcessId == processId)
+                    {
+                        Logger.Info($"Found child process '{process.Format()}'.");
+                        children.Add(process);
+                        continue;
+                    }
+
+                Next:
+                    process.Dispose();
+                }
+                catch (Exception e) when (e is InvalidOperationException || e is Win32Exception)
+                {
+                    process.Dispose();
+                }
+            }
+
+            return children;
+        }
+    }
+}