v1 of systemd service management

SS14.Watchdog/Components/ProcessManagement/IProcessManager.cs

@@ -41,12 +41,86 @@ public sealed record ProcessStartData(
 /// </summary>
 public interface IProcessHandle
 {
-    bool HasExited { get; }
-    int ExitCode { get; }
-
     void DumpProcess(string file, DumpType type);
 
     Task WaitForExitAsync(CancellationToken cancel = default);
 
-    void Kill();
+    Task Kill();
+
+    Task<ProcessExitStatus?> GetExitStatusAsync();
+}
+
+/// <summary>
+/// Status for how a process has exited.
+/// </summary>
+/// <param name="Reason">The reason why the process exited. Check the enum for possible values.</param>
+/// <param name="Status">
+/// Reason-specific value.
+/// For <see cref="ProcessExitReason.ExitCode"/> this is the exit code.
+/// For <see cref="ProcessExitReason.Signal"/> and <see cref="ProcessExitReason.CoreDumped"/> this is the signal that killed the process.
+/// </param>
+/// <seealso cref="IProcessHandle"/>
+public sealed record ProcessExitStatus(ProcessExitReason Reason, int Status)
+{
+    public ProcessExitStatus(ProcessExitReason reason) : this(reason, 0)
+    {
+    }
+
+    public bool IsClean => Reason == ProcessExitReason.ExitCode && Status == 0 || Reason == ProcessExitReason.Success;
+}
+
+/// <summary>
+/// Reason values for <see cref="ProcessExitStatus"/>.
+/// </summary>
+public enum ProcessExitReason
+{
+    // These somewhat correspond to systemd's values for "Result" on a Service, kinda.
+    // https://www.freedesktop.org/software/systemd/man/org.freedesktop.systemd1.html#Properties2
+
+    /// <summary>
+    /// Process exited "successfully" according to systemd.
+    /// </summary>
+    /// <remarks>
+    /// This probably means exit code 0, but I want to distinguish them as technically they're not equal.
+    /// </remarks>
+    Success,
+
+    /// <summary>
+    /// Process exited recorded exit code.
+    /// </summary>
+    ExitCode,
+
+    /// <summary>
+    /// Process was killed by uncaught signal.
+    /// </summary>
+    /// <remarks>
+    /// This won't apply if the process is killed with SIGTERM,
+    /// as the game handles that and manually returns exit code signum + 128.
+    /// </remarks>
+    Signal,
+
+    /// <summary>
+    /// Process crashed and dumped core.
+    /// </summary>
+    CoreDump,
+
+    /// <summary>
+    /// Systemd operation failed.
+    /// </summary>
+    SystemdFailed,
+
+    /// <summary>
+    /// Timeout executing service operation.
+    /// </summary>
+    Timeout,
+
+    /// <summary>
+    /// Process was killed by the Linux OOM killer.
+    /// </summary>
+    OomKill,
+
+    /// <summary>
+    /// Catch-all for other unhandled status codes.
+    /// </summary>
+    Other,
 }

SS14.Watchdog/Components/ProcessManagement/ProcessManagerBasic.cs

@@ -168,9 +168,6 @@ private sealed class Handle : IProcessHandle
     {
         private readonly Process _process;
 
-        public bool HasExited => _process.HasExited;
-        public int ExitCode => _process.ExitCode;
-
         public Handle(Process process)
         {
             _process = process;
@@ -187,9 +184,20 @@ public async Task WaitForExitAsync(CancellationToken cancel = default)
             await _process.WaitForExitAsync(cancel);
         }
 
-        public void Kill()
+        public Task<ProcessExitStatus?> GetExitStatusAsync()
+        {
+            if (!_process.HasExited)
+                return Task.FromResult<ProcessExitStatus?>(null);
+
+            var code = _process.ExitCode;
+            return Task.FromResult<ProcessExitStatus?>(new ProcessExitStatus(ProcessExitReason.ExitCode, code));
+        }
+
+        public Task Kill()
         {
             _process.Kill(entireProcessTree: true);
+
+            return Task.CompletedTask;
         }
     }
 }