windows-server-2003/net/config/dbgext

README file for sample WINDBG (old stlye) extension simple.dll





This extsnsion dll shows how to write a simple extension and demostrates use of APIs in wdbgexts.h





Mandatory routines which must be implemented and exported for windbg style extensions:

VOID

WinDbgExtensionDllInit(

    PWINDBG_EXTENSION_APIS lpExtensionApis,

    USHORT MajorVersion,

    USHORT MinorVersion

    )



This is called on loading extension dll. Global variables and flags for extension should be initialized in this routine. One 

of the useful things to initialize is WINDBG_WNTENSION_APIS which has some commonly used APIS for memory reads and I/O.







LPEXT_API_VERSION

ExtensionApiVersion(

    VOID

    )

This tells debugger about version of the extension dll. The values returned by this will determine how extension of this

dll will be called. A common error while writing extensions is mismatched values of version returned be this routine as 

compared to what version dll was built with.



This has ApiVersion = { (VER_PRODUCTVERSION_W >> 8), 

                   (VER_PRODUCTVERSION_W & 0xff), 

                   EXT_API_VERSION_NUMBER64, 

                    0 };





VOID

CheckVersion(

    VOID

    )

This is called after the dll is loaded by the debugger. The extension dll can verify here if it was loaded for correct target.









Extension Calls

---------------



EXT_API_VERSION_NUMBER64 is needed for making 64-bit aware extensions, all addresses for these will then be ULONG64s, for this

an extension is defined as:

CPPMOD VOID 

extension(

        HANDLE                 hCurrentProcess,

        HANDLE                 hCurrentThread,

        ULONG64                dwCurrentPc,

        ULONG                  dwProcessor,

        PCSTR                  args

     )





Extensions

----------





help



Every extension dll should have one extension called 'help' which shows descriptions for extensions that are present in the dll.