Rebrand! Rebrand!

CMakeLists.txt

@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.17.0)
 
 # Start Project
-project(trampoline)
+project(runtime)
 
 # Headers
 add_library(trampoline-headers INTERFACE)
@@ -11,23 +11,23 @@ target_include_directories(trampoline-headers INTERFACE include)
 if(NOT TRAMPOLINE_HEADERS_ONLY)
     # Check Architecture
     include(CheckSymbolExists)
-    check_symbol_exists("__aarch64__" "" USE_NATIVE_TRAMPOLINE)
+    check_symbol_exists("__aarch64__" "" USE_NATIVE_RUNTIME)
-    check_symbol_exists("__x86_64__" "" USE_QEMU_TRAMPOLINE)
+    check_symbol_exists("__x86_64__" "" USE_QEMU_RUNTIME)
 
     # Include Correct Sub-Project
-    set(TRAMPOLINE_RPATH "$ORIGIN/../lib/native")
+    set(RUNTIME_RPATH "$ORIGIN/../lib/native")
-    set(TRAMPOLINE_EXTRA_LINK_FLAG "--disable-new-dtags")
+    set(RUNTIME_EXTRA_LINK_FLAG "--disable-new-dtags")
-    if(USE_NATIVE_TRAMPOLINE)
+    target_compile_definitions(trampoline-headers INTERFACE MCPI_BUILD_RUNTIME)
+    if(USE_NATIVE_RUNTIME)
         add_subdirectory(native)
-        target_compile_definitions(trampoline-headers INTERFACE MCPI_USE_NATIVE_TRAMPOLINE)
+    elseif(USE_QEMU_RUNTIME)
-    elseif(USE_QEMU_TRAMPOLINE)
         add_subdirectory(qemu)
-        target_compile_definitions(trampoline-headers INTERFACE MCPI_USE_QEMU)
+        target_compile_definitions(trampoline-headers INTERFACE MCPI_RUNTIME_IS_QEMU)
     else()
         message(FATAL_ERROR "Unsupported Architecture")
     endif()
 else()
     # No-Op Install Function
-    function(install_trampoline)
+    function(install_runtime)
     endfunction()
 endif()

README.md

@@ -0,0 +1,19 @@
+# MCPI Runtime
+**Fact:** MCPI is a 32-bit ARM binary.
+
+**Another fact:** Most modern computers do not use 32-bit ARM and therefore cannot run MCPI natively.
+
+**Solution:** This project allows MCPI to run on modern computers.
+
+## How
+This project works differently depending on the host system's architecture.
+
+### 64-Bit x86 Host
+On this platform, a patched version of QEMU is used.
+
+QEMU emulates ARM code so MCPI can run on x86 hardware. And the patch adds a system-call which allows MCPI to run graphics code on the host. This prevents the need for emulated GPU drivers.
+
+### 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.

native/CMakeLists.txt

@@ -1,27 +1,25 @@
-project(native-trampoline)
+project(native-runtime)
 
 # Build
-add_executable(trampoline
+add_executable(runtime
     src/memory.cpp
     src/main.cpp
     src/trampoline.cpp
-    src/ptrace/loop.cpp
-    src/ptrace/init.cpp
     src/pipe.cpp
     src/signals.cpp
 )
 
 # Warnings
-target_compile_options(trampoline PRIVATE -Wall -Wextra -Werror -Wpointer-arith -Wshadow -Wnull-dereference)
+target_compile_options(runtime PRIVATE -Wall -Wextra -Werror -Wpointer-arith -Wshadow -Wnull-dereference)
 
 # Link
-target_link_libraries(trampoline dl rt trampoline-headers)
+target_link_libraries(runtime dl rt trampoline-headers)
 
 # RPath
-set_target_properties(trampoline PROPERTIES INSTALL_RPATH "${TRAMPOLINE_RPATH}")
+set_target_properties(runtime PROPERTIES INSTALL_RPATH "${RUNTIME_RPATH}")
-target_link_options(trampoline PRIVATE "LINKER:${TRAMPOLINE_EXTRA_LINK_FLAG}")
+target_link_options(runtime PRIVATE "LINKER:${RUNTIME_EXTRA_LINK_FLAG}")
 
 # Install
-function(install_trampoline bin_dir)
+function(install_runtime bin_dir)
-    install(TARGETS trampoline DESTINATION "${bin_dir}")
+    install(TARGETS runtime DESTINATION "${bin_dir}")
 endfunction()

native/src/log.h

@@ -5,6 +5,6 @@
 
 #define ERR(format, ...) \
     { \
-        fprintf(stderr, "TRAMPOLINE ERROR: " format "\n", ##__VA_ARGS__); \
+        fprintf(stderr, "RUNTIME ERROR: " format "\n", ##__VA_ARGS__); \
          exit(EXIT_FAILURE); \
     }

native/src/main.cpp

@@ -2,6 +2,7 @@
 #include <cstring>
 #include <cerrno>
 #include <sys/wait.h>
+#include <sys/prctl.h>
 
 #include "log.h"
 #include "memory.h"
@@ -25,6 +26,8 @@ int main(__attribute__((unused)) int argc, char *argv[]) {
         // Setup
         setpgid(0, 0);
         init_pipe_guest();
+        // Kill Child If Parent Exits First
+        prctl(PR_SET_PDEATHSIG, SIGKILL);
         // Execute Program
         execvp(argv[1], (char *const *) &argv[1]);
         ERR("Unable To Execute Program: %s: %s", argv[1], strerror(errno));

native/src/memory.cpp

@@ -10,21 +10,6 @@ static pid_t guest_pid;
 void init_memory(pid_t pid) {
     guest_pid = pid;
 }
-void memory_reader(uint32_t guest_addr, void *data, uint32_t size) {
-    if (size == 0) {
-        return;
-    }
-    iovec local[1];
-    local[0].iov_base = data;
-    local[0].iov_len = size;
-    iovec remote[1];
-    remote[0].iov_base = (void *) (uint64_t) guest_addr;
-    remote[0].iov_len = size;
-    const ssize_t ret = process_vm_readv(guest_pid, local, 1, remote, 1, 0);
-    if (ret != size) {
-        ERR("Unable To Read Data: %s", strerror(errno));
-    }
-}
 void memory_writer(uint32_t guest_addr, const void *data, uint32_t size) {
     iovec local[1];
     local[0].iov_base = (void *) data;

native/src/memory.h

@@ -4,6 +4,5 @@
 #include <sys/types.h>
 
 // Read External Memory
-void memory_reader(uint32_t guest_addr, void *data, uint32_t size);
 void memory_writer(uint32_t guest_addr, const void *data, uint32_t size);
 void init_memory(pid_t guest_pid);

qemu/CMakeLists.txt

@@ -6,7 +6,7 @@ if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.24.0)
 endif()
 
 # Archive
-if(NOT DEFINED TRAMPOLINE_QEMU_ARCHIVE)
+if(NOT DEFINED RUNTIME_QEMU_ARCHIVE)
     message(FATAL_ERROR "Missing QEMU Archive")
 endif()
 
@@ -24,7 +24,7 @@ if(DEFINED ENV{PKG_CONFIG_LIBDIR})
 endif()
 set(EXTRA_C_FLAGS "-s -I${CMAKE_CURRENT_SOURCE_DIR}/../include")
 ExternalProject_Add(qemu
-    URL "${TRAMPOLINE_QEMU_ARCHIVE}"
+    URL "${RUNTIME_QEMU_ARCHIVE}"
     # Configure Build
     CONFIGURE_COMMAND
         "${CMAKE_COMMAND}" "-E" "env"
@@ -36,7 +36,7 @@ ExternalProject_Add(qemu
         "--cross-prefix="
         "--cc=${CMAKE_C_COMPILER}"
         "--cxx=${CMAKE_CXX_COMPILER}"
-        "--extra-ldflags=-ldl -Wl,-rpath=${TRAMPOLINE_RPATH} -Wl,${TRAMPOLINE_EXTRA_LINK_FLAG}"
+        "--extra-ldflags=-ldl -Wl,-rpath=${RUNTIME_RPATH} -Wl,${RUNTIME_EXTRA_LINK_FLAG}"
         "--disable-debug-info"
         "--target-list=arm-linux-user"
         "--without-default-features"
@@ -54,9 +54,9 @@ ExternalProject_Add(qemu
 )
 
 # Install
-function(install_trampoline bin_dir legal_dir)
+function(install_runtime bin_dir legal_dir)
     ExternalProject_Get_property(qemu BINARY_DIR)
-    install(PROGRAMS "${BINARY_DIR}/qemu-arm" DESTINATION "${bin_dir}" RENAME "trampoline")
+    install(PROGRAMS "${BINARY_DIR}/qemu-arm" DESTINATION "${bin_dir}" RENAME "runtime")
     # License
     ExternalProject_Get_property(qemu SOURCE_DIR)
     install(FILES "${SOURCE_DIR}/COPYING" DESTINATION "${legal_dir}/qemu")