Running Powershell script causes 'Memory corruption' or 'Cannot Read or Write'

Question

Im making a program that makes a Wi-Fi hotspot for you and enables Internet Connection Sharing automaticly using a powershell script.

The script works and runs perfectly, but i have to wait for it to be finished so i can notify the user its done. Im using below code which works but...

but it crashes and causes an error on my home computer which is allot faster. I get a Cannot read or write or memory is corrupt error which i can't really explain.

public static void ToggleIcs(string connectionInterface, bool state)
    {
        string toggle;
        string par1;
        string par2;
        if (state){
            toggle = "EnableSharing";
            par1 = "0";
            par2 = "1";
        }else{
            toggle = "DisableSharing";
            par1 = "";
            par2 = "";
        }
        using (PowerShell powerShellInstance = PowerShell.Create())
        {
            // this script enables or disables internet sharing with the connectionInterface given.
            powerShellInstance.AddScript("" +
                "regsvr32 hnetcfg.dll /s;" +
                "$m = New-Object -ComObject HNetCfg.HNetShare;" +
                "$m.EnumEveryConnection |% { $m.NetConnectionProps.Invoke($_) };" +
                "$c = $m.EnumEveryConnection |? { $m.NetConnectionProps.Invoke($_).Name -eq '" + connectionInterface + "' };" +
                "$config = $m.INetSharingConfigurationForINetConnection.Invoke($c);" +
                "Write-Output $config.SharingEnabled;" +
                "Write-Output $config.SharingConnectionType;" +
                "$config." + toggle + "(" + par1 + ");" +

                "$m2 = New-Object -ComObject HNetCfg.HNetShare;" +
                "$m2.EnumEveryConnection |% { $m2.NetConnectionProps.Invoke($_) };" +
                "$c2 = $m2.EnumEveryConnection |? { $m2.NetConnectionProps.Invoke($_).DeviceName -Match 'Microsoft Hosted Network Virtual Adapter' };" +
                "$config2 = $m2.INetSharingConfigurationForINetConnection.Invoke($c2);" +
                "Write-Output $config2.SharingEnabled;" +
                "Write-Output $config2.SharingConnectionType;" +
                "$config." + toggle + "(" + par2 + ");");


            PSDataCollection<PSObject> outputCollection = new PSDataCollection<PSObject>();
            IAsyncResult result = powerShellInstance.BeginInvoke<PSObject, PSObject>(null, outputCollection);
            Console.WriteLine(DateTime.Now + ">> Started Powershell script");

            int i = 0;
            while (!result.IsCompleted)
            {
                if (i < 60)
                {
                    Console.WriteLine(DateTime.Now + ">> Running script");
                }
                else
                {
                    ScriptFailed();
                    powerShellInstance.Stop();
                    break;
                }
                i++;
                Thread.Sleep(1000);
            }
            Console.WriteLine(DateTime.Now + ">> Executed Internet Sharing script");
        }
    }

This is the error im getting:

Attempted to read or write protected memory. This is often an indication that other memory is corrupt.

I don't get a line that says where it crashes but it crashes after Thread.Sleep(1000);. Which i found out using breakpoints

As I said, the script runs fine on my laptop, and it does work on my faster computer, but it crashes as soon as it hits Thread.Sleep(1000). After it crashed, I checked if ICS was enabled in the network and sharing center, and and it did so correctly.

I tried removing the Thread.Sleep(1000); but then it crashes anyway a line before.

What can I try or do differently?

Edit

i dont have the stack trace yet, as i am not on my faster PC where it crashes. but I will post it as soon as possible.

Edit

As mentioned by TheLethalCoder, it could be that i try to acces IsCompleted While it is being updated. If that is why it happens, How would I check if it is being altered or wait for it to be done.
Edit

As i dont really know what the call stack is for, or what a stack trace is, and how i can use it ill provide an image of what i saw one moment before the crash.

Edit I did some snooping around and found a few things i tried.

first, in the application properties -> build, i ticked "Prefer 32bit" off Because some people fixed their problems with this. And i did not get a crash but the script also failed to run and caused my internet connection to drop.
so i turned it back on. I also tried the netsh winsock reset command and restarting my pc but it still crashed.

Im all out of clues now, but i posted these two things for people who come by looking for an answer and maybe this will work.

I can't get that yet because Im working right now and it works fine on this machine, but i will post it as soon as possible — Jeremy V.
– Jeremy V., Commented Jan 19, 2017 at 10:54
Seeing as that error indicates something happened inside unsafe code and you are not using unsafe code I believe it is more to do with the script than the C# code. — TheLethalCoder
– TheLethalCoder, Commented Jan 19, 2017 at 10:54
@TheLethalCoder I ran the script on my faster machine line for line in Powershell without an error and it worked fine. Is there a difference in running it with C#? — Jeremy V.
– Jeremy V., Commented Jan 19, 2017 at 10:57
Whenever I get an error like that it is because I am using pointers in C# in an unsafe context to access Bitmaps faster. You're C# code, as far as I can tell, isn't doing anything with pointers or in an unsafe context. That was all I was pointing out. But I don't know what the underlying classes you are using are doing so they could use some unsafe methods... — TheLethalCoder
– TheLethalCoder, Commented Jan 19, 2017 at 10:59

TheLethalCoder · Accepted Answer · 2017-01-19 11:33:29Z

1

The MSDN article: Polling for the Status of an Asynchronous Operation states that the way you are polling the result is correct. However their example doesn't include a Thread.Sleep:

while (result.IsCompleted != true)
{
    UpdateUserInterface();
}

So to eliminate this I would use the following snippet that keeps track of the variables without sleeping, note that printing to the Console on every loop is going to quickly pollute the window though:

Stopwatch sw = new Stopwatch();
sw.Start();
while (!result.IsCompleted)
{
    if (sw.EllapsedMilliseconds >= 60000) //60 seconds
    {
        break;
    }

    Console.WriteLine(DateTime.Now + ">> Running script");
}

if (!result.IsCompleted)
{
    ScriptFailed();
    powerShellInstance.Stop();
}

_{This is more of a comment than an answer but it was getting too long to be used as a comment.}

answered Jan 19, 2017 at 11:33

TheLethalCoder

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2 Comments

Jeremy V. Over a year ago

It actually makes more sense to wait for it like this, because it runs better than Thread.Sleep(1000); because that blocks the thread. So thanks for this improvement, but I do know it didn't matter if I used Thread.Sleep() or not because it crashed even without it. Still very useful.

TheLethalCoder Over a year ago

@Jeremy Like I said it's more of a comment than an answer but with all the markdown and it's length I couldn't really do that

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