RE: [DotGNU]How mscoree.dll works

[Jeroen Frijters]

To get started:
Set HKLM\Software\Microsoft\.NETFramework\InstallRoot (registry) to another
directory that contains a subdirectory v1.0.3705 that contains an
mscorwks.dll.

mscorwks.dll should contain:

extern "C" void __stdcall CorExeMain(DWORD flags, HMODULE hModule)
{
        HMODULE hMain = GetModuleHandle(0);
}

CorExeMain should be exported as _CorExeMain (without @0 that __stdcall
normally adds). hMain is a pointer the in memory copy of the managed EXE
file that triggered the load. I'm just guessing at the parameters, but I'm
pretty sure that hModule is the module handle of mscorwks.dll. No idea about
the flags.

Regards,
Jeroen

> -----Original Message-----
> From: Rhys Weatherley [mailto:address@hidden 
> Sent: Thursday, December 19, 2002 12:55
> To: address@hidden
> Subject: [DotGNU]How mscoree.dll works
> 
> 
> I've performed some investigations into how Microsoft's 
> "mscoree.dll" works to 
> auto-launch the CLR when an IL program is executed directly by name.
> 
> The version of the DLL that is installed in C:\WINNT\System32 
> (on my w2k box 
> with the latest .NET Framework SDK installed) seems to 
> contain a bunch of 
> stubs.  Each entry point loads another DLL and then passes 
> control to that 
> instead.  e.g.  this is what "_CorExeMain" looks like, more 
> or less (ignoring 
> error handling):
> 
>     int _CorExeMain()
>     {
>         HINSTANCE hInst = GetRealEngine();
>         LPVOID addr = GetProcAddress(hInst, "_CorExeMain");
>         return (*addr)();
>     }
> 
> i.e. it finds the "real" engine DLL, and passes control to it.  The 
> "GetRealEngine" function (a name that I made up - it probably 
> isn't actually 
> called that) appears to look in the registry for the actual 
> runtime engine.  
> But that's basically where I got stumped.  I wasn't able to 
> figure out which 
> registry settings were being used.
> 
> So, it does look relatively promising - if we can figure out 
> which registry 
> settings are being read, we could theoretically provide a 
> "pnet/MS/Mono/Rotor" switching program to allow the user to 
> switch between 
> engines easily, with each engine providing its own "real 
> engine" DLL.  
> Alternatively, we can replace "mscoree.dll" with our own 
> version that handles 
> switching.
> 
> Since I'm not really a Windows internals person, I'm 
> basically stumped at this 
> point.  I'd appreciate any assistance from the community in 
> tracking this 
> down further.
> 
> Cheers,
> 
> Rhys.
> 
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