Generate / create mdump files for in my app

Question

Im looking for a way to generate minidump files in my applications simular to what ProcDump does but prefarably with code and not having to extract a 3dparty tool to do it.

The main reasons for not wanting to use ProcDump is:
1) Size of the binary would increase greatly ( This is a problem because my apps are freeware, and bandwith is not free).
2) Feels dirty.
3) No way i can port that app to run inn windows mobile.

My requirements are:
1) Ability to generate mdump files in a fatale crash.
2) Abilityt to do "pause" the app do a dump, and contiune would be a bonus
.
If this is not realy a option, is there a way to get the values of local varibales in the current context dynamicly?

Side note: I did find this article, but its very old so i so im hesitant to base my work of it.
There seems to either be a issue with IE 9 or with the site, so i had problems with tags.

Answer 1

You can call MiniDumpWriteDump from AppDomain.UnhandledException or Application.ThreadException event handler to create the minidump. This article explains the function in great details: Effective minidumps

You can also use this library which has other functionality too: Catch All Bugs with BugTrap!

Edit

Looks like getting a useful minidump is not that easy. First of all sos.dll complains when the dump is not full (full dumps are about 100-150MB). Secondly, writing dump in catch block is not recommended: Getting good dumps when an exception is thrown.

If you have a winforms application this question has some usefull info: How does SetUnhandledExceptionFilter work in .NET WinForms applications?

Answer 2

So there is one solution that comes to mind and meets the following goals:

• Size of the binary would increase by around 300k
• Ability to generate mdump files in a fatale crash.
• Ability to do "pause" the app do a dump, and contiune would be a bonus

I'll give this requirement a complete unknown:

• No way i can port that app to run inn windows mobile.

So what's the solution?

Integrate the required parts you need from the Microsoft Sample for MDbg.exe to provide you with a 'just-in-time' debugger that attaches, dumps, and detaches from the crashing process.

Step 1 - Start by downloading the source code to the mdbg from here: http://www.microsoft.com/downloads/en/details.aspx?FamilyID=38449a42-6b7a-4e28-80ce-c55645ab1310&DisplayLang=en

Step 2 - Create a 'crash' handler that spawns a debugger process and waits for completion. I used the following few lines of code to re-launch the same exe with a few extra arguments to invoke the debugger and output an xml file to std::out.

string tempFile = Path.GetTempFileName();
Mutex handle = new Mutex(true, typeof(Program).Namespace + "-self-debugging");
try
{
    Process pDebug = Process.Start(typeof(Program).Assembly.Location,
        "debug-dump " + Process.GetCurrentProcess().Id + " " + tempFile);
    if (pDebug != null)
        pDebug.WaitForExit();
}
catch { }
finally
{
    handle.ReleaseMutex();
}

Console.WriteLine(File.ReadAllText(tempFile));

Step 3 - Write the debug dump routine, this can be in the same exe or in a different exe. You will need to reference (or include the source from) the 'raw', 'corapi', and 'mdbgeng' modules from the sample. Then add a few lines to your Main():

public static void Main(string[] args)
{
    if (args.Length > 0 && args[0] == "debug-dump")
    {   //debug-dump process by id = args[1], output = args[2]
        using (XmlTextWriter wtr = new XmlTextWriter(args[2], Encoding.ASCII))
        {
            wtr.Formatting = Formatting.Indented;
            PerformDebugDump(Int32.Parse(args[1]), wtr);
        }
        return;
    }
    //... continue normal program execution
}

static void PerformDebugDump(int process, XmlWriter x)
{
    x.WriteStartElement("process");
    x.WriteAttributeString("id", process.ToString());
    x.WriteAttributeString("time", XmlConvert.ToString(DateTime.Now, XmlDateTimeSerializationMode.RoundtripKind));

    MDbgEngine e = new MDbgEngine();
    MDbgProcess me = e.Attach(process);
    me.Go().WaitOne();

    try
    {
        x.WriteStartElement("modules");
        foreach (MDbgModule mod in me.Modules)
            x.WriteElementString("module", mod.CorModule.Name);
        x.WriteEndElement();

        foreach (MDbgThread thread in me.Threads)
        {
            x.WriteStartElement("thread");
            x.WriteAttributeString("id", thread.Id.ToString());
            x.WriteAttributeString("number", thread.Number.ToString());
            int ixstack = -1;

            foreach (MDbgFrame frame in thread.Frames)
            {
                x.WriteStartElement("frame");
                x.WriteAttributeString("ix", (++ixstack).ToString());
                x.WriteAttributeString("loc", frame.ToString(String.Empty));
                string valueText = null;

                x.WriteStartElement("args");
                try
                {
                    foreach (MDbgValue value in frame.Function.GetArguments(frame))
                    {
                        x.WriteStartElement(value.Name);
                        x.WriteAttributeString("type", value.TypeName);
                        try { x.WriteAttributeString("value", value.GetStringValue(1, false)); }
                        finally { x.WriteEndElement(); }
                    }
                }
                catch { }
                x.WriteEndElement();

                x.WriteStartElement("locals");
                try
                {
                    foreach (MDbgValue value in frame.Function.GetActiveLocalVars(frame))
                    {
                        x.WriteStartElement(value.Name);
                        x.WriteAttributeString("type", value.TypeName);
                        try { x.WriteAttributeString("value", value.GetStringValue(1, false)); }
                        finally { x.WriteEndElement(); }
                    }
                }
                catch { }
                x.WriteEndElement();
                x.WriteEndElement();
            }
            x.WriteEndElement();
        }
    }
    finally
    {
        me.Detach().WaitOne();
    }

    x.WriteEndElement();
}

Example Output

<process id="8276" time="2010-10-18T16:03:59.3781465-05:00">
<modules>
<module>C:\Windows\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089\mscorlib.dll</module>
...etc
</modules>
<thread id="17208" number="0">
<frame ix="0" loc="System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop (source line information unavailable)">
    <args>
        <this type="System.Windows.Forms.Application.ComponentManager" value="System.Windows.Forms.Application.ComponentManager&#xA;    oleComponents=System.Collections.Hashtable&#xA; cookieCounter=1&#xA;    activeComponent=System.Windows.Forms.Application.ThreadContext&#xA; trackingComponent=&lt;null&gt;&#xA; currentState=0" />
        <dwComponentID type="N/A" value="&lt;N/A&gt;" />
        <reason type="System.Int32" value="-1" />
        <pvLoopData type="System.Int32" value="0" />
    </args>
    <locals>
        <local_0 type="System.Int32" value="0" />
        <local_1 type="System.Boolean" value="True" />
        <local_2 type="System.Windows.Forms.UnsafeNativeMethods.IMsoComponent" value="&lt;null&gt;" />
        <local_3 type="N/A" value="&lt;N/A&gt;" />
        <local_4 type="N/A" value="&lt;N/A&gt;" />
        <local_5 type="N/A" value="&lt;N/A&gt;" />
        <local_6 type="System.Windows.Forms.Application.ThreadContext" value="System.Windows.Forms.Application.ThreadContext&#xA;   contextHash=System.Collections.Hashtable&#xA;   tcInternalSyncObject=System.Object&#xA; totalMessageLoopCount=1&#xA;    baseLoopReason=-1&#xA;  currentThreadContext=System.Windows.Forms.Application.ThreadContext&#xA;    threadExceptionHandler=System.Threading.ThreadExceptionEventHandler&#xA;    idleHandler=&lt;null&gt;&#xA;   enterModalHandler=&lt;null&gt;&#xA; leaveModalHandler=&lt;null&gt;&#xA; applicationContext=System.Windows.Forms.ApplicationContext&#xA; parkingWindow=&lt;null&gt;&#xA; marshalingControl=System.Windows.Forms.Application.MarshalingControl&#xA;   culture=&lt;null&gt;&#xA;   messageFilters=&lt;null&gt;&#xA;    messageFilterSnapshot=&lt;null&gt;&#xA; handle=912&#xA; id=17208&#xA;   messageLoopCount=1&#xA; threadState=1&#xA;  modalCount=0&#xA;   activatingControlRef=&lt;null&gt;&#xA;  componentManager=System.Windows.Forms.Application.ComponentManager&#xA; externalComponentManager=False&#xA; fetchingComponentManager=False&#xA; componentID=1&#xA;  currentForm=Program.MainForm&#xA;   threadWindows=&lt;null&gt;&#xA; tempMsg=System.Windows.Forms.NativeMethods.MSG&#xA; disposeCount=0&#xA; ourModalLoop=False&#xA; messageLoopCallback=&lt;null&gt;&#xA;   __identity=&lt;null&gt;" />
        <local_7 type="N/A" value="&lt;N/A&gt;" />
        <local_8 type="N/A" value="&lt;N/A&gt;" />
        <local_9 type="N/A" value="&lt;N/A&gt;" />
        <local_10 type="N/A" value="&lt;N/A&gt;" />
        <local_11 type="N/A" value="&lt;N/A&gt;" />
        <local_12 type="N/A" value="&lt;N/A&gt;" />
        <local_13 type="System.Boolean" value="False" />
        <local_14 type="System.Windows.Forms.NativeMethods.MSG[]" value="array [1]&#xA; [0] = System.Windows.Forms.NativeMethods.MSG" />
    </locals>
</frame>
<frame ix="1" loc="System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner (source line information unavailable)">
    <args>
        <this type="System.Windows.Forms.Application.ThreadContext" value="System.Windows.Forms.Application.ThreadContext&#xA;  contextHash=System.Collections.Hashtable&#xA;   tcInternalSyncObject=System.Object&#xA; totalMessageLoopCount=1&#xA;    baseLoopReason=-1&#xA;  currentThreadContext=System.Windows.Forms.Application.ThreadContext&#xA;    threadExceptionHandler=System.Threading.ThreadExceptionEventHandler&#xA;    idleHandler=&lt;null&gt;&#xA;   enterModalHandler=&lt;null&gt;&#xA; leaveModalHandler=&lt;null&gt;&#xA; applicationContext=System.Windows.Forms.ApplicationContext&#xA; parkingWindow=&lt;null&gt;&#xA; marshalingControl=System.Windows.Forms.Application.MarshalingControl&#xA;   culture=&lt;null&gt;&#xA;   messageFilters=&lt;null&gt;&#xA;    messageFilterSnapshot=&lt;null&gt;&#xA; handle=912&#xA; id=17208&#xA;   messageLoopCount=1&#xA; threadState=1&#xA;  modalCount=0&#xA;   activatingControlRef=&lt;null&gt;&#xA;  componentManager=System.Windows.Forms.Application.ComponentManager&#xA; externalComponentManager=False&#xA; fetchingComponentManager=False&#xA; componentID=1&#xA;  currentForm=Program.MainForm&#xA;   threadWindows=&lt;null&gt;&#xA; tempMsg=System.Windows.Forms.NativeMethods.MSG&#xA; disposeCount=0&#xA; ourModalLoop=False&#xA; messageLoopCallback=&lt;null&gt;&#xA;   __identity=&lt;null&gt;" />
        <reason type="System.Int32" value="-1" />
        <context type="System.Windows.Forms.ApplicationContext" value="System.Windows.Forms.ApplicationContext&#xA; mainForm=Program.MainForm&#xA;  userData=&lt;null&gt;&#xA;  ThreadExit=System.EventHandler" />
    </args>
    <locals>
        <local_0 type="System.Windows.Forms.Form" value="&lt;null&gt;" />
        <local_1 type="System.Boolean" value="False" />
        <local_2 type="N/A" value="&lt;N/A&gt;" />
        <local_3 type="N/A" value="&lt;N/A&gt;" />
        <local_4 type="N/A" value="&lt;N/A&gt;" />
    </locals>
</frame>
... etc
</thread>
</process>

Since you have the full power of a debugger there is nothing stopping you from writing as much or as little as you like, but the above example should get you started.

UPDATE

This works with the .Net 2.0 and/or 3.5 runtime without any further dependencies.

This can debug .Net 2.0/3.5 code running in a .Net 4.0 process; however, it does not work with 4.0 (yet).

For 4.0 CLR see this post: http://blogs.msdn.com/b/rmbyers/archive/2008/10/27/icordebug-re-architecture-in-clr-4-0.aspx