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.
