Graceful Ctrl+C handling

[thekid]

Can we make PHP handle Ctrl+C gracefully by intercepting it inside .NET? Something like installing a signal handler for SIGINT but platform independent.

See https://msdn.microsoft.com/en-us/library/system.console.cancelkeypress.aspx

[thekid]

Handling Ctrl+C inside C#:

using System;
using System.Threading;

public class CtrlC
{
    public static void Main()
    {
        Console.WriteLine("Started");
        Console.CancelKeyPress += (sender, args) => {
            Console.WriteLine("Interrupted");
            args.Cancel = true;
        };
        Thread.Sleep(5000);
        Console.WriteLine("Ended");
    }
}

Inside the handler we'd need to call into the PHP subprocess - but how?

[thekid]

Seems like Windows PHP would need to use SetConsoleCtrlHandler and not just cleanup and exit, but instead e.g. raise an exception. According to MSDN it's exeucted in a new thread - could that work or would it completely mess up PHP?

[thekid]

See https://nomadphp.com/rfcs-future-tick-talk/ - for Unix systems w/ PCNTL, this will be easy and maybe the framework can take care of it. For Windows, we need a different solution - maybe based on ticks + IPC?

[thekid]

For Cygwin, we'll need to wrap xp inside something like this:

#!/bin/sh 

_term() { 
  echo "Caught SIGINT signal!" 
  kill -TERM "$child" 2>/dev/null
}

trap _term SIGINT

/home/friebe/bin/xp "$@" &

child=$! 
wait "$child"

See https://unix.stackexchange.com/questions/146756/forward-sigterm-to-child-in-bash

[thekid]

For Cygwin, using winpty -- xp should also work.

[thekid]

For Cygwin, using winpty -- xp should also work.

The wrapper above doesn't, actually only winpty works as expected:

diff --git a/src/xp.runner/exec/ExecutionModel.cs b/src/xp.runner/exec/ExecutionModel.cs
index 6caa29a..82657d2 100755
--- a/src/xp.runner/exec/ExecutionModel.cs
+++ b/src/xp.runner/exec/ExecutionModel.cs
@@ -18,6 +18,13 @@ namespace Xp.Runners.Exec
         /// <summary>Run the process and return its exitcode</summary>
         protected int Run(Process proc, Encoding encoding, Func<int> wait = null)
         {
+            Console.CancelKeyPress += (sender, args) => {
+                args.Cancel = true;
+
+                Console.WriteLine("Killing PHP");
+                proc.Kill();
+            };
+
             using (new Output())
             {
                 proc.StartInfo.RedirectStandardOutput = false;
@@ -29,11 +36,14 @@ namespace Xp.Runners.Exec

                     if (null == wait)
                     {
+                Console.WriteLine("WaitForExit");
                         proc.WaitForExit();
+                Console.WriteLine("Waited {0}", proc.ExitCode);
                         return proc.ExitCode;
                     }
                     else
                     {
+                Console.WriteLine("wait");
                         return wait();
                     }
                 }

$ cat xp.sh
#!/bin/bash

./winpty ./xp.exe "$@"

# Without interrupting
$ sh xp.sh -e 'sleep(2)'
WaitForExit
Waited 0

# With ^C
$ sh xp.sh -e 'sleep(2)'
WaitForExit
Killing PHP
Waited -1073741510

$ echo $?
58

[thekid]

WinPTY can be obtained by downloading https://github.com/rprichard/winpty/releases

[thekid]

<?php

$ffi= FFI::cdef('
  typedef bool (close_handler)(int reason);
  bool SetConsoleCtrlHandler(close_handler handler, bool add);
', 'kernel32.dll');

$f= function($reason) {
  echo "Exiting with $reason...\n";
  return false;
};
var_dump($ffi->SetConsoleCtrlHandler($f, true));
sleep(10);

$ XP_RT=master winpty xp ffi.php
bool(true)
# Press Ctrl+C here
Exiting with 0...

[thekid]

Using Windows Terminal (Preview):