initial commit

README.md

@@ -1,2 +1,6 @@
 # python3-win7-shim
-Shim DLL to run unpatched Python3.8+ on Win7
+This is a shim DLL to run unpatched Python3.8+ on Windows 7. This built specifically for Python and is not a full featured, general purpose replacement for `api-ms-win-core-path-l1-1-0.dll`.
+
+It passes through these functions, and only works with `PATHCCH_NONE` flags:<br>
+`PathCchCanonicalizeEx() => PathCanonicalizeW()`<br>
+`PathCchCombineEx() => PathCombineW()`

build.bat

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+@echo off
+REM   Make sure to run rustup install stable-i686-pc-windows-msvc
+REM                    rustup install stable-x86_64-pc-windows-msvc
+
+rmdir 64bit /s /q
+rmdir 32bit /s /q
+mkdir 64bit
+mkdir 32bit
+rustup default stable-i686-pc-windows-msvc
+rustc --target i686-pc-windows-msvc -C panic=abort -C target-feature=+crt-static -o 32bit/api-ms-win-core-path-l1-1-0.dll lib.rs
+rustup default stable-x86_64-pc-windows-msvc
+rustc --target x86_64-pc-windows-msvc -C panic=abort -C target-feature=+crt-static -o 64bit/api-ms-win-core-path-l1-1-0.dll lib.rs

lib.rs

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+#![crate_type = "cdylib"]
+#![no_std]
+
+#[panic_handler]
+unsafe fn panic(_panic: &core::panic::PanicInfo) -> ! { ExitProcess(1); loop { } }
+
+#[no_mangle]
+unsafe extern "system" fn _DllMainCRTStartup(_: *const u8, _: u32, _: *const u8) -> u32 { 1 }
+
+#[link(name = "kernel32")]
+#[allow(non_snake_case)]
+extern "stdcall" {
+    fn ExitProcess(exit_code: u32) -> ();
+}
+
+#[link(name = "shlwapi")]
+#[allow(non_snake_case)]
+extern "stdcall" {
+    fn PathCanonicalizeW(path_out: *mut u8, path: *const u8) -> bool;
+    fn PathCombineW(path_out: *mut u8, dir: *const u8, file: *const u8) -> usize;
+}
+
+const MAX_PATH: usize = 256;
+const S_OK: u32 = 0;
+const E_INVALIDARG: u32 = 0x80070057;
+const PATHCCH_NONE: u32 = 0; 
+
+
+#[no_mangle]
+pub unsafe extern "stdcall" fn PathCchCanonicalizeEx(path_out_buf: *mut u8, buf_size: usize, path: *const u8, flags: u32) -> u32 {
+	if flags != PATHCCH_NONE || buf_size < MAX_PATH { return E_INVALIDARG; }
+	let success = PathCanonicalizeW(path_out_buf, path);
+	return if success { S_OK } else { E_INVALIDARG };
+}
+
+#[no_mangle]
+pub unsafe extern "stdcall" fn PathCchCombineEx(path_out_buf: *mut u8, buf_size: usize, path: *const u8, path_more: *const u8, flags: u32) -> u32 {
+	if flags != PATHCCH_NONE || buf_size < MAX_PATH { return E_INVALIDARG; }
+	let str_ptr = PathCombineW(path_out_buf, path, path_more);
+	return if str_ptr > 0 { S_OK } else { E_INVALIDARG };
+}