Steam Nano Patcher (SNP)

This was made to apply skins to Steam without installing anything else, while being small.

It can also load other binaries to extend its functionality and is compatible with Millennium skin configurations.

Installation

Steam's CEF debugger must be enabled.

You can do so by either adding a file named .cef-enable-remote-debugging inside Steam's folder or starting it with the -cef-enable-debugging argument.

After that, get a binary or compile one and choose how you want to install it.

Scripts will be updated independently of tagged releases.

Executable (exe folder)

1. Place src/js/injector/injector.js / scripts/js/injector/injector.js in steam_nano_patcher/js/injector, relative to the executable.

2. Place src/js/ThemeInjector.js / scripts/js/ThemeInjector.js in <steamfolder>/steamui/steam_nano_patcher.

3. Place src/lua, the contents of each subfolder from external/lua and external/c/civetweb/civetweb.h in steam_nano_patcher/lua, relative to the executable.

   scripts/lua can be copied directly instead of manually making the folder.

4. Run it alongside Steam.

Injector / Library (lib folder)

Steps 1, 2 and 3 are the same, but relative to Steam's folder.

Linux only: Add the following code to any of Steam's scripts (/usr/lib/steam/ or <steamfolder>/steam.sh, the former is recommended):

export SNP_LOADER_PATH="<absolute path to the loader binary>"
export SNP_CURRENT_PROC="$(basename "$0")"
export SNP_SEARCH_PROC="steam"
export LD_PRELOAD="${SNP_LOADER_PATH}${LD_PRELOAD:+:$LD_PRELOAD}"

NOTE

Steam checks the size of steam.sh and will replace the script if it's incorrect. Try removing comments from it.

Custom scripts can also be used.

See https://github.com/SteamClientHomebrew/Millennium/pull/503 and https://github.com/SteamClientHomebrew/Millennium/issues/475

1. Place the dynamic libraries inside Steam's folder.
2. Run Steam.

NOTE

You might need to restart Steam after it fully finishes loading.

The patcher will not be injected if Steam wants to update (it executes another binary before the main one) or if it has already updated (the script was reset).

Since Steam is a 32-bit application, the injected code must also be the same architecture.

This is not the case for macOS, as it's 64-bit only.

Configuration

Loader

steam_nano_patcher/settings.json

{
	"loadOtherModules": false,
	"modules": {
		"steam_nano_patcher": {
			"path": "steam_nano_patcher",
			"entryPoint": "SNPEntryPoint"
		}
	}
}

IMPORTANT THE DEFAULT ENTRY MUST BE FIRST OR OTHERS CAN BE LOADED BEFORE IT.

No hash checking is done.

On Windows and Linux the extension is appended automatically for every module.

Patcher

steam_nano_patcher/patcher_settings.json

{
	"injectorPath": "steam_nano_patcher/js/injector/injector.js",
	"luaScript": "steam_nano_patcher/lua/script.lua",
	"steamPort": 8080,
	"debug": false,
	"printRPCMessages": false,
	"autoreconnect": false,
	"exitOnLoopEnd": true,
	"connectionDelay": null
}

The debug option enables printRPCMessages and opens a console on Windows if the loader is a library.

exitOnLoopEnd is executable only.

On Linux you might need to change connectionDelay. The value is in seconds and should be 3 or more. Windows is delayed already (for some reason).

Injector configuration

Read src/js/injector/injector.js.

All assets loaded using steamloopback.host are inside <steamfolder>/steamui.

Skin configuration

Read src/js/ThemeInjector.js.

Caveats

1. It cannot load dynamic libraries that have standard entry points (Millennium included).
2. There is no GUI for configuration, only JSON and JavaScript.

Compilation

Zig is needed to compile this.

Read build.zig or type zig build --help inside the root folder to see the available options.

Credits

• Millennium
• SFP