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Implement handling POSIX signals (#1954)
* Implement handling POSIX signals * Improve handling of exceptions in signal handlers
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2 files changed

+132
-24
lines changed

2 files changed

+132
-24
lines changed

‎src/core/IronPython.Modules/signal.PosixSignalState.cs

+102
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,102 @@
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// Licensed to the .NET Foundation under one or more agreements.
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// The .NET Foundation licenses this file to you under the Apache 2.0 License.
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// See the LICENSE file in the project root for more information.
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#nullable enable
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#if FEATURE_PROCESS
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#if NET
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using System;
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using System.Runtime.InteropServices;
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using System.Runtime.Versioning;
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using Mono.Unix;
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using Mono.Unix.Native;
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using IronPython.Runtime;
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using IronPython.Runtime.Operations;
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using System.Threading.Tasks;
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using Microsoft.Scripting.Runtime;
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using Microsoft.Scripting.Hosting.Shell;
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namespace IronPython.Modules {
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public static partial class PythonSignal {
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[SupportedOSPlatform("linux")]
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[SupportedOSPlatform("macos")]
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private class PosixSignalState : PythonSignalState {
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private readonly PosixSignalRegistration?[] _signalRegistrations;
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private ConsoleCancelEventHandler? _consoleHandler;
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public PosixSignalState(PythonContext pc) : base(pc) {
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_signalRegistrations = new PosixSignalRegistration[NSIG];
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}
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protected override void Dispose(bool disposing) {
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if (disposing) {
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Array.ForEach(_signalRegistrations, reg => reg?.Dispose());
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Array.Clear(_signalRegistrations, 0, _signalRegistrations.Length);
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}
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base.Dispose(disposing);
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}
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public override void SetPyHandler(int signalnum, object value) {
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// normalize handler reference
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if (value is int i) {
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value = (i == SIG_IGN) ? sig_ign : sig_dfl;
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}
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if (TryGetPyHandler(signalnum, out object? existingValue) && ReferenceEquals(existingValue, value)) {
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// no change
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return;
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}
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base.SetPyHandler(signalnum, value);
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if (signalnum == SIGINT) {
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// SIGINT is special, we need to disable the handler on the console so that we can handle Ctrl+C here
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if (DefaultContext.DefaultPythonContext.Console is BasicConsole console) {
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if (!ReferenceEquals(value, default_int_handler)) {
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// save the console handler so it can be restored later if necessary
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_consoleHandler ??= console.ConsoleCancelEventHandler;
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// disable the console handler
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console.ConsoleCancelEventHandler = null;
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} else if (_consoleHandler != null) {
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// default_int_handler: restore the console handler, which is de facto default_int_handler
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console.ConsoleCancelEventHandler = _consoleHandler;
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_consoleHandler = null;
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}
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}
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}
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// remember to unregister any previous handler
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var oldReg = _signalRegistrations[signalnum];
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if (ReferenceEquals(value, sig_dfl)) {
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_signalRegistrations[signalnum] = null;
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} else if (ReferenceEquals(value, sig_ign)) {
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_signalRegistrations[signalnum] = PosixSignalRegistration.Create((PosixSignal)signalnum,
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(PosixSignalContext psc) => {
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psc.Cancel = true;
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});
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} else {
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_signalRegistrations[signalnum] = PosixSignalRegistration.Create((PosixSignal)signalnum,
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(PosixSignalContext psc) => {
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// This is called on a thread from the thread pool for most signals,
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// and on a dedicated thread ".NET Signal Handler" for SIGINT, SIGQUIT, and SIGTERM.
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CallPythonHandler(signalnum, value);
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psc.Cancel = true;
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});
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}
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oldReg?.Dispose();
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}
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}
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}
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}
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#endif // NET
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#endif // FEATURE_PROCESS

‎src/core/IronPython.Modules/signal.cs

+30-24
Original file line numberDiff line numberDiff line change
@@ -76,8 +76,12 @@ private static PythonSignalState MakeNtSignalState(PythonContext context) {
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[SupportedOSPlatform("macos")]
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[MethodImpl(MethodImplOptions.NoInlining)]
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private static PythonSignalState MakePosixSignalState(PythonContext context) {
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// Use SimpleSignalState until the real Posix one is written
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return new SimpleSignalState(context);
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#if NET
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return new PosixSignalState(context);
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#else
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// PosixSignalState depends on PosixSignalRegistration, which is not available in Mono or .NET Standard 2.0
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return new SimpleSignalState(context);
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#endif
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}
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@@ -439,12 +443,15 @@ private class PythonSignalState : IDisposable {
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/// </remarks>
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protected readonly object?[] PySignalToPyHandler;
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protected readonly object sig_dfl;
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protected readonly object sig_ign;
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public PythonSignalState(PythonContext pc) {
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SignalPythonContext = pc;
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PySignalToPyHandler = new object[NSIG];
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object sig_dfl = ScriptingRuntimeHelpers.Int32ToObject(SIG_DFL);
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object sig_ign = ScriptingRuntimeHelpers.Int32ToObject(SIG_IGN);
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sig_dfl = ScriptingRuntimeHelpers.Int32ToObject(SIG_DFL);
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sig_ign = ScriptingRuntimeHelpers.Int32ToObject(SIG_IGN);
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int[] sigs = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) ? _PySupportedSignals_Windows
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: RuntimeInformation.IsOSPlatform(OSPlatform.OSX) ? _PySupportedSignals_MacOS
@@ -488,27 +495,26 @@ public virtual void SetPyHandler(int signalnum, object value)
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protected void CallPythonHandler(int signum, object? handler) {
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if (handler is null) return;
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if (handler == default_int_handler) {
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// We're dealing with the default_int_handlerImpl which we
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// know doesn't care about the frame parameter
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default_int_handlerImpl(signum, null);
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return;
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} else {
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// We're dealing with a callable matching PySignalHandler's signature
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try {
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PySignalHandler temp = (PySignalHandler)Converter.ConvertToDelegate(handler,
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typeof(PySignalHandler));
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if (SignalPythonContext.PythonOptions.Frames) {
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temp.Invoke(signum, SysModule._getframeImpl(null,
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0,
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SignalPythonContext._mainThreadFunctionStack));
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} else {
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temp.Invoke(signum, null);
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}
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} catch (Exception ex) {
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System.Console.WriteLine(SignalPythonContext.FormatException(ex));
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try {
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if (handler == default_int_handler) {
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// We're dealing with the default_int_handlerImpl which we
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// know doesn't care about the frame parameter
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default_int_handlerImpl(signum, null);
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} else {
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// We're dealing with a callable matching PySignalHandler's signature
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PySignalHandler temp = (PySignalHandler)Converter.ConvertToDelegate(handler,
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typeof(PySignalHandler));
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if (SignalPythonContext.PythonOptions.Frames) {
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temp.Invoke(signum, SysModule._getframeImpl(null,
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0,
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SignalPythonContext._mainThreadFunctionStack));
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} else {
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temp.Invoke(signum, null);
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}
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}
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} catch (Exception ex) {
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SignalPythonContext.DomainManager.SharedIO.ErrorWriter.WriteLine(SignalPythonContext.FormatException(ex));
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}
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}
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