syscall - msvc-compatible inline dynamic x64 syscall invocation for windows

What?

This library provides functionality to dynamically parse and invoke x64 windows syscalls (specifically windows nt syscalls) using a simple macro.

How?

To avoid using any common windows api like GetModuleHandle or GetProcAddress the PEB_LDR_DATA in the Process Environment Block (PEB) is manually walked to get the base address of ntdll.dll to parse the exports table of ntdll.dll and parse all possible syscall indexes for Nt apis and store them in a map. Using cpp templates and macros a higher level function and macro is provided to provide a easy to use interface for invoking a specific Nt-Api/Syscall using a small asm stub.

Why?

The already existing similar project inline_syscall is great but only works on clang, so I've hacked this together by basically combining aspects of both inline_syscall and Hells Gate.

Limits

Due to way the syscall gets invoked this project does not support multithreading without the possibility of undefined behaviour.

Example

NTSTATUS status = SYSCALL(NtClose)((HANDLE)-1);