FEAT(client): add Source Engine plugin, retract Left 4 Dead 1 & 2 plugins

5df2bb2c0bdf91ed078e3cd3fafb04bdec5333c8 explains how we gain access to the game's interfaces.

Once we have access to the interfaces, we retrieve the address of the variables' we're interested in by reading the assembly of one or more functions accessing them.

The process for each function is documented in the code.

2 files changed, 6 insertions, 199 deletions

diff --git a/plugins/l4d/CMakeLists.txt b/plugins/l4d/CMakeLists.txt
index 7a429da99..9413ad4b5 100644
--- a/plugins/l4d/CMakeLists.txt
+++ b/plugins/l4d/CMakeLists.txt
@@ -3,4 +3,9 @@
 # that can be found in the LICENSE file at the root of the
 # Mumble source tree or at <https://www.mumble.info/LICENSE>.
 
-add_library(l4d SHARED "l4d.cpp")
+set(PLUGIN_RETRACTED ON PARENT_SCOPE)
+if(retracted-plugins)
+	add_library(l4d SHARED "../null_plugin.cpp")
+
+	target_compile_definitions(l4d PRIVATE "NULL_DESC=L\"Left 4 Dead (retracted, now using Source Engine plugin)\"")
+endif()
diff --git a/plugins/l4d/l4d.cpp b/plugins/l4d/l4d.cpp
deleted file mode 100644
index 81ec76103..000000000
--- a/plugins/l4d/l4d.cpp
+++ /dev/null
@@ -1,198 +0,0 @@
-// Copyright 2005-2020 The Mumble Developers. All rights reserved.
-// Use of this source code is governed by a BSD-style license
-// that can be found in the LICENSE file at the root of the
-// Mumble source tree or at <https://www.mumble.info/LICENSE>.
-
-#include "../mumble_plugin_main.h"  // Include standard plugin header.
-#include "../mumble_plugin_utils.h" // Include plugin header for special functions, like "escape".
-
-static procptr_t steamclient, engine; // Variables to contain modules addresses
-
-static int fetch(float *avatar_pos, float *avatar_front, float *avatar_top, float *camera_pos, float *camera_front,
-				 float *camera_top, std::string &context, std::wstring &identity) {
-	for (int i = 0; i < 3; i++) {
-		avatar_pos[i] = avatar_front[i] = avatar_top[i] = camera_pos[i] = camera_front[i] = camera_top[i] = 0.0f;
-	}
-
-	// Boolean value to check if game addresses retrieval is successful
-	bool ok;
-	// Create containers to stuff our raw data into, so we can convert it to Mumble's coordinate system
-	float avatar_pos_corrector[3], camera_pos_corrector[3], camera_front_corrector[3], camera_top_corrector[3];
-	// Char values for extra features
-	char serverid[22], host[22], map[30], playerid[22];
-	// State
-	bool state;
-
-	// State pointers
-	procptr_t state_base = peekProcPtr(pModule + 0x5A7354);
-	if (state_base == 0)
-		return false;
-	procptr_t state_offset = peekProcPtr(state_base + 0x5C);
-	if (state_offset == 0)
-		return false;
-
-	// Peekproc and assign game addresses to our containers, so we can retrieve positional data
-	ok = peekProc(state_offset + 0x8, state) && // Magical state value: 0 when not playing and 1 when in-game.
-		 peekProc(pModule + 0x512264, avatar_pos_corrector) &&   // Avatar position values (X, Z and Y).
-		 peekProc(pModule + 0x5943B0, camera_pos_corrector) &&   // Camera position values (X, Z and Y).
-		 peekProc(pModule + 0x594410, camera_front_corrector) && // Front vector values (X, Z and Y).
-		 peekProc(pModule + 0x594440, camera_top_corrector) &&   // Top vector values (X, Z and Y).
-		 peekProc(steamclient + 0x95E56D, serverid) &&           // Unique server Steam ID.
-		 peekProc(engine + 0x61F5D8, host) && // Server value: "IP:Port" (xxx.xxx.xxx.xxx:yyyyy) when in a remote server
-											  // and "loopback" when on a local server.
-		 peekProc(pModule + 0x5A7A29, map) && // Map name.
-		 peekProc(engine + 0x40CF00, playerid); // Unique player Steam ID.
-
-	// This prevents the plugin from linking to the game in case something goes wrong during values retrieval from
-	// memory addresses.
-	if (!ok)
-		return false;
-
-	// State
-	if (!state) {         // If not in-game
-		context.clear();  // Clear context
-		identity.clear(); // Clear identity
-
-		// Set vectors values to 0.
-		for (int i = 0; i < 3; i++) {
-			avatar_pos[i] = avatar_front[i] = avatar_top[i] = camera_pos[i] = camera_front[i] = camera_top[i] = 0.0f;
-		}
-
-		return true; // This tells Mumble to ignore all vectors.
-	}
-
-	// Begin context
-	escape(serverid, sizeof(serverid));
-	escape(host, sizeof(host));
-	std::ostringstream ocontext;
-	if (strcmp(serverid, "") != 0) {
-		ocontext << " {\"Server ID\": \"" << serverid << "\"}"; // Set context with server ID
-	} else {
-		ocontext << " {\"Host\": \"" << host << "\"}"; // Set context with IP address and port
-	}
-
-	context = ocontext.str();
-	// End context
-
-	// Begin identity
-	std::wostringstream oidentity;
-	oidentity << "{";
-
-	// Host
-	if (strcmp(host, "") != 0
-		&& !strstr(host, "loopback")) { // Only include host (IP:Port) if it is not empty and does not include the
-										// string "loopback" (which means it's a local server).
-		oidentity << std::endl << "\"Host\": \"" << host << "\","; // Set host address in identity.
-	} else {
-		oidentity << std::endl << "\"Host\": null,";
-	}
-
-	// Map
-	escape(map, sizeof(map));
-	if (strcmp(map, "") != 0) {
-		oidentity << std::endl << "\"Map\": \"" << map << "\","; // Set map name in identity.
-	} else {
-		oidentity << std::endl << "\"Map\": null,";
-	}
-
-	// Player ID
-	escape(playerid, sizeof(playerid));
-	if (strcmp(playerid, "") != 0) {
-		oidentity << std::endl << "\"Player ID\": \"" << playerid << "\""; // Set player ID in identity.
-	} else {
-		oidentity << std::endl << "\"Player ID\": null";
-	}
-
-	oidentity << std::endl << "}";
-	identity = oidentity.str();
-	// End identity
-
-	/*
-	Mumble | Game
-	X      | X
-	Y      | Z
-	Z      | Y
-	*/
-	avatar_pos[0] = avatar_pos_corrector[0];
-	avatar_pos[1] = avatar_pos_corrector[2];
-	avatar_pos[2] = avatar_pos_corrector[1];
-
-	camera_pos[0] = camera_pos_corrector[0];
-	camera_pos[1] = camera_pos_corrector[2];
-	camera_pos[2] = camera_pos_corrector[1];
-
-	camera_front[0] = camera_front_corrector[0];
-	camera_front[1] = camera_front_corrector[2];
-	camera_front[2] = camera_front_corrector[1];
-
-	camera_top[0] = camera_top_corrector[0];
-	camera_top[1] = camera_top_corrector[2];
-	camera_top[2] = camera_top_corrector[1];
-
-	// Convert from inches to meters and sync avatar vectors with camera ones
-	for (int i = 0; i < 3; i++) {
-		avatar_pos[i] /= 39.37f;
-		camera_pos[i] /= 39.37f;
-		avatar_front[i] = camera_front[i];
-		avatar_top[i]   = camera_top[i];
-	}
-
-	return true;
-}
-
-static int trylock(const std::multimap< std::wstring, unsigned long long int > &pids) {
-	if (!initialize(pids, L"left4dead.exe", L"client.dll")) { // Retrieve "client.dll" module's memory address
-		return false;
-	}
-
-	// Server ID
-	steamclient = getModuleAddr(L"steamclient.dll"); // Retrieve "steamclient.dll" module's memory address
-	// This prevents the plugin from linking to the game in case something goes wrong during module's memory address
-	// retrieval.
-	if (steamclient == 0)
-		return false;
-
-	// Host & Player ID
-	engine = getModuleAddr(L"engine.dll"); // Retrieve "engine.dll" module's memory address
-	// This prevents the plugin from linking to the game in case something goes wrong during module's memory address
-	// retrieval.
-	if (engine == 0)
-		return false;
-
-	// Check if we can get meaningful data from it
-	float apos[3], afront[3], atop[3], cpos[3], cfront[3], ctop[3];
-	std::wstring sidentity;
-	std::string scontext;
-
-	if (fetch(apos, afront, atop, cpos, cfront, ctop, scontext, sidentity)) {
-		return true;
-	} else {
-		generic_unlock();
-		return false;
-	}
-}
-
-static const std::wstring longdesc() {
-	return std::wstring(
-		L"Supports Left 4 Dead version 1.0.3.1 with context and identity support."); // Plugin long description
-}
-
-static std::wstring description(L"Left 4 Dead (v1.0.3.1)"); // Plugin short description
-static std::wstring shortname(L"Left 4 Dead");              // Plugin short name
-
-static int trylock1() {
-	return trylock(std::multimap< std::wstring, unsigned long long int >());
-}
-
-static MumblePlugin l4dplug = { MUMBLE_PLUGIN_MAGIC, description, shortname, nullptr, nullptr, trylock1,
-								generic_unlock,      longdesc,    fetch };
-
-static MumblePlugin2 l4dplug2 = { MUMBLE_PLUGIN_MAGIC_2, MUMBLE_PLUGIN_VERSION, trylock };
-
-extern "C" MUMBLE_PLUGIN_EXPORT MumblePlugin *getMumblePlugin() {
-	return &l4dplug;
-}
-
-extern "C" MUMBLE_PLUGIN_EXPORT MumblePlugin2 *getMumblePlugin2() {
-	return &l4dplug2;
-}