private static async Task <bool> SendSignalFromCurrentProcess(int processId, NativeMethods.CtrlType signal)
{
await SignalFromCurrentProcessLock.WaitAsync().ConfigureAwait(false);
try
{
using (var waitForSignalSemaphore = new SemaphoreSlim(initialCount: 0, maxCount: 1))
{
NativeMethods.ConsoleCtrlDelegate handler = receivedSignal =>
{
if (receivedSignal == signal)
{
waitForSignalSemaphore.Release();
// if we're signaling another process on the same console, we return true
// to prevent the signal from bubbling. If we're signaling ourselves, we
// allow it to bubble since presumably that's what the caller wanted
return(processId != ProcessHelper.CurrentProcessId);
}
return(false);
};
if (!NativeMethods.SetConsoleCtrlHandler(handler, add: true))
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
try
{
if (!NativeMethods.GenerateConsoleCtrlEvent(signal, NativeMethods.AllProcessesWithCurrentConsoleGroup))
{
return(false);
}
// Wait until the signal has reached our handler and been handled to know that it is safe to
// remove the handler.
// Timeout here just to ensure we don't hang forever if something weird happens (e. g. someone
// else registers a handler concurrently with us).
return(await waitForSignalSemaphore.WaitAsync(TimeSpan.FromSeconds(30)).ConfigureAwait(false));
}
finally
{
if (!NativeMethods.SetConsoleCtrlHandler(handler, add: false))
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
}
}
}
finally
{
SignalFromCurrentProcessLock.Release();
}
}
public async Task CanSendSignalToSelf(int signal)
{
if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
{
Assert.Pass("Tests windows-specific behavior");
}
Command.TryAttachToProcess(ProcessHelper.CurrentProcessId, out var thisCommand).ShouldEqual(true);
using (var manualResetEvent = new ManualResetEventSlim(initialState: false))
{
NativeMethods.ConsoleCtrlDelegate handler = receivedSignal =>
{
if ((int)receivedSignal == signal)
{
manualResetEvent.Set();
return(true); // handled
}
return(false);
};
if (!NativeMethods.SetConsoleCtrlHandler(handler, add: true))
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
try
{
(await thisCommand.TrySignalAsync(CommandSignal.FromSystemValue(signal))).ShouldEqual(true);
manualResetEvent.Wait(TimeSpan.FromSeconds(5)).ShouldEqual(true);
}
finally
{
if (!NativeMethods.SetConsoleCtrlHandler(handler, add: false))
{
Marshal.ThrowExceptionForHR(Marshal.GetHRForLastWin32Error());
}
}
}
}