murder-processes.cs

public async Task KillProcessNicely(uint pid, int delayInMs = 3*1000)
{
    // Ugh, this is gross - https://stackoverflow.com/questions/16653517/how-best-to-post-wm-quit-to-a-running-process
    var tids = NativeMethods.GetAllTopLevelWindowsInZOrder()
        .Select(hwnd => {
            uint wndpid = 0;
            var tid = NativeMethods.GetWindowThreadProcessId(hwnd, out wndpid);
            if (wndpid != pid) {
                return (uint)0;
            }

            return tid;
        })
        .ToArray();

    if (tids.Length == 0) {
        // NB: They somehow don't have a message queue? Straight
        // to Murdertown it is.
        try {
            var ps = Process.GetProcessById((int)pid);
            ps.Kill();
        } catch (Exception ex) {
            this.Log().Warn(ex, $"Failed to force-kill PID 0x{pid:x}");
        }
    }

    // Post WM_QUIT to any thread queue we can find
    foreach (var tid in tids) {
        if (tid < 1) continue;

        this.Log().Info($"Attempting to post WM_QUIT to PID 0x{pid:x}");
        NativeMethods.PostThreadMessage(tid, 0x12 /* WM_QUIT */, IntPtr.Zero, IntPtr.Zero);
    }

    Process proc;
    try {
        proc = Process.GetProcessById((int)pid);
    } catch (Exception ex) {
        // Process might have already bought it?
        this.Log().Warn(ex, $"Failed to OpenProcess on PID 0x{pid:x}");
        return;
    }

    try {
        var cts = new CancellationTokenSource();
        cts.CancelAfter(delayInMs);

        await NativeMethods.WaitForProcessExit(pid, cts.Token);
    } catch (OperationCanceledException) {
        proc.Kill();
    } catch (Exception ex) {
        // More race conditions
        this.Log().Warn(ex, $"Failed to force-kill PID 0x{pid:x}");
        return;
    }
}

I couldn't find the following pinvoke references. Can you reference them somewhere?

NativeMethods.GetAllTopLevelWindowsInZOrder()
NativeMethods.WaitForProcessExit(pid, cts.Token)

@anaisbetts ?

        [DllImport("user32.dll", SetLastError = true)]
        public static extern IntPtr GetTopWindow(IntPtr hwnd);

        [DllImport("user32.dll", SetLastError = true, EntryPoint = "GetWindow")]
        public static extern IntPtr GetNextWindow(IntPtr hwnd, GNWDirection wCmd);

        public static IEnumerable<IntPtr> GetAllTopLevelWindowsInZOrder()
        {
            var ret = GetTopWindow(IntPtr.Zero);
            if (ret == IntPtr.Zero) throw new Win32Exception();

            do {
                yield return ret;
                ret = GetNextWindow(ret, GNWDirection.GW_HWNDNEXT);
            } while (ret != IntPtr.Zero);
        }

        public static Task WaitForProcessExit(uint pid, CancellationToken cs)
        {
            try {
                var p = Process.GetProcessById((int)pid);

                return Task.Factory.StartNew(() => {
                    while (!p.WaitForExit(1000)) {
                        cs.ThrowIfCancellationRequested();
                    }
                }, TaskCreationOptions.LongRunning);
            } catch (Exception e) {
                return Task.FromException(e);
            }
        }