Changes

CMakeLists.txt

@@ -11,20 +11,22 @@ target_include_directories(trampoline-headers INTERFACE include)
 if(NOT TRAMPOLINE_HEADERS_ONLY)
     # Check Architecture
     include(CheckSymbolExists)
-    check_symbol_exists("__aarch64__" "" USE_NATIVE_RUNTIME)
-    check_symbol_exists("__x86_64__" "" USE_QEMU_RUNTIME)
-
-    # Include Correct Sub-Project
-    set(RUNTIME_RPATH "$ORIGIN/../lib/native")
-    set(RUNTIME_EXTRA_LINK_FLAG "--disable-new-dtags")
-    target_compile_definitions(trampoline-headers INTERFACE MCPI_BUILD_RUNTIME)
-    if(USE_NATIVE_RUNTIME)
-        add_subdirectory(native)
-    elseif(USE_QEMU_RUNTIME)
-        add_subdirectory(qemu)
-        target_compile_definitions(trampoline-headers INTERFACE MCPI_RUNTIME_IS_QEMU)
-    else()
-        message(FATAL_ERROR "Unsupported Architecture")
+    check_symbol_exists("__arm__" "" NO_RUNTIME_NEEDED)
+    if(NOT NO_RUNTIME_NEEDED)
+        check_symbol_exists("__aarch64__" "" USE_NATIVE_RUNTIME)
+        check_symbol_exists("__x86_64__" "" USE_QEMU_RUNTIME)
+        # Include Correct Sub-Project
+        set(RUNTIME_RPATH "$ORIGIN/../lib/native")
+        set(RUNTIME_EXTRA_LINK_FLAG "--disable-new-dtags")
+        target_compile_definitions(trampoline-headers INTERFACE MCPI_BUILD_RUNTIME)
+        if(USE_NATIVE_RUNTIME)
+            add_subdirectory(native)
+        elseif(USE_QEMU_RUNTIME)
+            add_subdirectory(qemu)
+            target_compile_definitions(trampoline-headers INTERFACE MCPI_RUNTIME_IS_QEMU)
+        else()
+            message(FATAL_ERROR "Unsupported Architecture")
+        endif()
     endif()
 else()
     # No-Op Install Function

README.md

@@ -1,5 +1,5 @@
-# MCPI Runtime
-**Fact:** MCPI is a 32-bit ARM binary.
+# MCPI-Reborn Runtime
+**Fact:** Minecraft: Pi Edition is a 32-bit ARM program.
 
 **Another fact:** Most modern computers do not use 32-bit ARM and therefore cannot run MCPI natively.
 
@@ -16,4 +16,10 @@ QEMU emulates ARM code so MCPI can run on x86 hardware. And the patch adds a sys
 ### 64-Bit ARM Host
 QEMU is not necessary on this platform because it can already run 32-bit ARM code natively.
 
-Instead, the runtime is implemented as two processes: a parent and a child. The child becomes MCPI and can send graphics commands to the parent. And because the parent is 64-bit, 32-bit drivers are not needed.
+Instead, the runtime is implemented as two processes: a parent and a child. The child becomes MCPI and can send graphics commands to the parent. And because the parent is 64-bit, 32-bit drivers are not needed.
+
+### 32-Bit ARM Host
+This project is unnecessary on this platform.
+
+### Other Architectures
+Any unlisted platforms are unsupported.

native/src/main.cpp

@@ -6,7 +6,6 @@
 
 #include "log.h"
 #include "memory.h"
-#include "trampoline.h"
 #include "pipe.h"
 #include "signals.h"
 
@@ -37,7 +36,6 @@ int main(__attribute__((unused)) int argc, char *argv[]) {
         // Setup Trampoline
         init_signals(pid);
         init_memory(pid);
-        init_trampoline();
 
         // Start Pipes
         init_pipe_host(pid);

native/src/pipe.cpp

@@ -46,6 +46,7 @@ void init_pipe_host(pid_t guest_pid) {
     // Wait For Commands
     trampoline_pipe_arguments cmd = {};
     while (read(arguments_pipe[PIPE_READ], &cmd, sizeof(trampoline_pipe_arguments)) > 0) {
+        init_trampoline(); // Only Init If Needed
         static unsigned char args[MAX_TRAMPOLINE_ARGS_SIZE];
         size_t position = 0;
         while (position < cmd.length) {

native/src/trampoline.cpp

@@ -13,6 +13,11 @@ uint32_t trampoline(uint32_t id, const unsigned char *args) {
 
 // Init
 void init_trampoline() {
+    static bool is_setup = false;
+    if (is_setup) {
+        return;
+    }
+    is_setup = true;
     // Open Library
     void *handle = dlopen("libmedia-layer-trampoline.so", RTLD_NOW);
     if (handle != nullptr) {