Runtime Refactor!

CMakeLists.txt

@@ -7,25 +7,51 @@ project(runtime)
 add_library(trampoline-headers INTERFACE)
 target_include_directories(trampoline-headers INTERFACE include)
 
+# Check Architecture
+include(CheckSymbolExists)
+check_symbol_exists("__arm__" "" NO_RUNTIME_NEEDED)
+if(NO_RUNTIME_NEEDED)
+    return()
+endif()
+
+# Only Headers
+option(TRAMPOLINE_HEADERS_ONLY "Skip Building Runtime" FALSE)
+if(TRAMPOLINE_HEADERS_ONLY)
+    return()
+endif()
+target_compile_definitions(trampoline-headers INTERFACE MCPI_BUILD_RUNTIME)
+
 # Build
-if(NOT TRAMPOLINE_HEADERS_ONLY)
-    # Check Architecture
-    include(CheckSymbolExists)
-    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 "$ORIGIN/../lib/native")
-        set(RUNTIME_EXTRA_LINK_FLAG "--disable-new-dtags")
-        target_compile_definitions(trampoline-headers INTERFACE MCPI_BUILD_RUNTIME)
-        if(USE_NATIVE_RUNTIME)
-            add_subdirectory(native)
-        elseif(USE_QEMU_RUNTIME)
-            add_subdirectory(qemu)
-            target_compile_definitions(trampoline-headers INTERFACE MCPI_RUNTIME_IS_QEMU)
-        else()
-            message(FATAL_ERROR "Unsupported Architecture")
-        endif()
-    endif()
+add_executable(runtime
+    src/main.cpp
+    src/trampoline.cpp
+    src/pipe/loop.cpp
+    src/pipe/main.cpp
+    src/pipe/memory.cpp
+)
+
+# QEMU
+check_symbol_exists("__x86_64__" "" USE_QEMU)
+if(USE_QEMU)
+    add_subdirectory(qemu)
+    target_sources(runtime PRIVATE
+        src/syscall/main.cpp
+        src/syscall/handler.cpp
+        src/qemu/qemu.cpp
+    )
+endif()
+
+# Warnings
+target_compile_options(runtime PRIVATE -Wall -Wextra -Werror -Wpointer-arith -Wshadow -Wnull-dereference)
+
+# Link
+target_link_libraries(runtime dl rt trampoline-headers)
+
+# RPath
+set_target_properties(runtime PROPERTIES INSTALL_RPATH "$ORIGIN/../lib/native")
+target_link_options(runtime PRIVATE "LINKER:--disable-new-dtags")
+
+# Install
+if(DEFINED MCPI_BIN_DIR)
+    install(TARGETS runtime DESTINATION "${MCPI_BIN_DIR}")
 endif()

include/trampoline/env-list.h

@@ -0,0 +1,3 @@
+ENV(MCPI_USE_PIPE_TRAMPOLINE, "Use The Pipe-Based Trampoline")
+ENV(_MCPI_TRAMPOLINE_ARGUMENTS, "")
+ENV(_MCPI_TRAMPOLINE_RETURN_VALUE, "")

include/trampoline/types.h

@@ -3,15 +3,13 @@
 #include <stdint.h>
 
 // Maximum Arguments Length
-#define MAX_TRAMPOLINE_ARGS_SIZE 2097152 // 2 MiB
+#define MAX_TRAMPOLINE_ARGS_SIZE 16777216 // 16 MiB
 
 // System Call Constants
 #define TRAMPOLINE_SYSCALL 0x1337
 #define QEMU_GUEST_BASE 0x40000 // Arbitrary Value (Aligns To 4k And 16k Page Sizes)
 
-// Pipe Constants
-#define TRAMPOLINE_ARGUMENTS_PIPE_ENV "_MCPI_TRAMPOLINE_ARGUMENTS"
-#define TRAMPOLINE_RETURN_VALUE_PIPE_ENV "_MCPI_TRAMPOLINE_RETURN_VALUE"
+// Pipe Command Structure
 struct trampoline_pipe_arguments {
     uint32_t id;
     uint32_t allow_early_return;
@@ -20,4 +18,9 @@ struct trampoline_pipe_arguments {
 
 // Function Types
 typedef void (*trampoline_writer_t)(uint32_t guest_addr, const void *data, uint32_t size);
-typedef uint32_t (*trampoline_t)(trampoline_writer_t writer, uint32_t id, const unsigned char *args);
+typedef uint32_t (*trampoline_t)(trampoline_writer_t writer, uint32_t id, const unsigned char *args);
+
+// Environmental Variables
+#define ENV(name, ...) constexpr const char *name##_ENV = #name;
+#include "env-list.h"
+#undef ENV

native/CMakeLists.txt

@@ -1,25 +0,0 @@
-project(native-runtime)
-
-# Build
-add_executable(runtime
-    src/memory.cpp
-    src/main.cpp
-    src/trampoline.cpp
-        src/loop.cpp
-    src/signals.cpp
-)
-
-# Warnings
-target_compile_options(runtime PRIVATE -Wall -Wextra -Werror -Wpointer-arith -Wshadow -Wnull-dereference)
-
-# Link
-target_link_libraries(runtime dl rt trampoline-headers)
-
-# RPath
-set_target_properties(runtime PROPERTIES INSTALL_RPATH "${RUNTIME_RPATH}")
-target_link_options(runtime PRIVATE "LINKER:${RUNTIME_EXTRA_LINK_FLAG}")
-
-# Install
-function(install_runtime bin_dir)
-    install(TARGETS runtime DESTINATION "${bin_dir}")
-endfunction()

native/src/loop.h

@@ -1,5 +0,0 @@
-#pragma once
-
-void create_pipes();
-void pipe_read_loop();
-void init_pipe_guest();

native/src/main.cpp

@@ -1,55 +0,0 @@
-#include <unistd.h>
-#include <cstring>
-#include <cerrno>
-#include <sys/wait.h>
-#include <sys/prctl.h>
-
-#include "log.h"
-#include "memory.h"
-#include "loop.h"
-#include "signals.h"
-
-// Main
-int main(__attribute__((unused)) int argc, char *argv[]) {
-    // Check Arguments
-    if (argc < 2) {
-        ERR("Invalid Arguments");
-    }
-    // Setup
-    create_pipes();
-    // Fork
-    pid_t pid = fork();
-    if (pid == -1) {
-        ERR("Unable To Fork Process: %s", strerror(errno));
-    } else if (pid == 0) {
-        // 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));
-    } else {
-        // Parent
-
-        // Setup Trampoline
-        init_signals(pid);
-        init_memory(pid);
-
-        // Read From Pipes
-        pipe_read_loop();
-
-        // Reap Child
-        int status;
-        if (waitpid(pid, &status, 0) == -1) {
-            ERR("Unable To Reap Child: %s", strerror(errno));
-        }
-        // Exit
-        if (WIFEXITED(status)) {
-            exit(WEXITSTATUS(status));
-        } else {
-            ERR("Unusual Exit");
-        }
-    }
-}

native/src/memory.cpp

@@ -1,24 +0,0 @@
-#include <sys/uio.h>
-#include <cstring>
-#include <cerrno>
-
-#include "memory.h"
-#include "log.h"
-
-// Read/Write Memory
-static pid_t guest_pid;
-void init_memory(pid_t pid) {
-    guest_pid = pid;
-}
-void memory_writer(uint32_t guest_addr, const void *data, uint32_t size) {
-    iovec local[1];
-    local[0].iov_base = (void *) 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_writev(guest_pid, local, 1, remote, 1, 0);
-    if (ret != size) {
-        ERR("Unable To Write Data: %#10x: %s", guest_addr, strerror(errno));
-    }
-}

native/src/memory.h

@@ -1,8 +0,0 @@
-#pragma once
-
-#include <cstdint>
-#include <sys/types.h>
-
-// Read External Memory
-void memory_writer(uint32_t guest_addr, const void *data, uint32_t size);
-void init_memory(pid_t guest_pid);

native/src/signals.cpp

@@ -1,24 +0,0 @@
-#include <sys/wait.h>
-
-#include "signals.h"
-
-// Signal Handlers
-static pid_t guest_pid = -1;
-static void exit_handler(__attribute__((unused)) int signal_id) {
-    // Stop Child
-    kill(guest_pid, SIGTERM);
-}
-
-// Init
-void init_signals(pid_t pid) {
-    guest_pid = pid;
-    // Install Signal Handlers
-    struct sigaction act_sigint = {};
-    act_sigint.sa_flags = SA_RESTART;
-    act_sigint.sa_handler = &exit_handler;
-    sigaction(SIGINT, &act_sigint, nullptr);
-    struct sigaction act_sigterm = {};
-    act_sigterm.sa_flags = SA_RESTART;
-    act_sigterm.sa_handler = &exit_handler;
-    sigaction(SIGTERM, &act_sigterm, nullptr);
-}

native/src/signals.h

@@ -1,5 +0,0 @@
-#pragma once
-
-#include <sys/types.h>
-
-void init_signals(pid_t guest_pid);

native/src/trampoline.h

@@ -1,6 +0,0 @@
-#pragma once
-
-#include <trampoline/types.h>
-
-uint32_t trampoline(uint32_t id, const unsigned char *args);
-void init_trampoline();

qemu/CMakeLists.txt

@@ -6,15 +6,13 @@ if(CMAKE_VERSION VERSION_GREATER_EQUAL 3.24.0)
 endif()
 
 # Archive
-if(NOT DEFINED RUNTIME_QEMU_ARCHIVE)
-    message(FATAL_ERROR "Missing QEMU Archive")
+set(RUNTIME_QEMU_ARCHIVE "" CACHE FILEPATH "QEMU Path")
+if(NOT EXISTS "${RUNTIME_QEMU_ARCHIVE}")
+    message(FATAL_ERROR "Missing QEMU Archive!")
 endif()
 
-# Flatpak Support
-set(QEMU_FLATPAK_PATCH "")
-if(MCPI_IS_FLATPAK_BUILD)
-    set(QEMU_FLATPAK_PATCH "sed" "-i" "s/libdrm/libdrm-dis/g" "<SOURCE_DIR>/meson.build")
-endif()
+# Library
+set(QEMU_LIBRARY "/lib/libqemu-arm.so")
 
 # Build
 include(ExternalProject)
@@ -22,42 +20,51 @@ set(PKGCONFIG_ENV "")
 if(DEFINED ENV{PKG_CONFIG_LIBDIR})
     set(PKGCONFIG_ENV "PKG_CONFIG_LIBDIR=$ENV{PKG_CONFIG_LIBDIR}")
 endif()
-set(EXTRA_C_FLAGS "-s -I${CMAKE_CURRENT_SOURCE_DIR}/../include")
 ExternalProject_Add(qemu
     URL "${RUNTIME_QEMU_ARCHIVE}"
     # Configure Build
     CONFIGURE_COMMAND
         "${CMAKE_COMMAND}" "-E" "env"
         ${PKGCONFIG_ENV}
-        "CFLAGS=${EXTRA_C_FLAGS}"
-        "CXXFLAGS=${EXTRA_C_FLAGS}"
         "<SOURCE_DIR>/configure"
-        "--prefix=${CMAKE_INSTALL_PREFIX}"
+        "--prefix=<INSTALL_DIR>"
         "--cross-prefix="
         "--cc=${CMAKE_C_COMPILER}"
         "--cxx=${CMAKE_CXX_COMPILER}"
-        "--extra-ldflags=-ldl -Wl,-rpath=${RUNTIME_RPATH} -Wl,${RUNTIME_EXTRA_LINK_FLAG}"
         "--disable-debug-info"
+        "--enable-strip"
+        "--enable-pie"
+        "--enable-lto"
+        "-Db_staticpic=true"
+        "-Db_lundef=false"
         "--target-list=arm-linux-user"
         "--without-default-features"
     USES_TERMINAL_CONFIGURE TRUE
     # Build Command
-    BUILD_COMMAND "ninja" "qemu-arm"
-    BUILD_BYPRODUCTS "<BINARY_DIR>/qemu-arm"
+    BUILD_COMMAND "ninja"
     USES_TERMINAL_BUILD TRUE
-    # Disable Install/Test Commands
-    INSTALL_COMMAND ""
+    # Install
+    INSTALL_DIR "${QEMU_INSTALL_DIR}"
+    INSTALL_COMMAND "ninja" "install"
+    INSTALL_BYPRODUCTS "<INSTALL_DIR>${QEMU_LIBRARY}"
+    # Disable Test Command
     TEST_COMMAND ""
     # Patch Command
-    PATCH_COMMAND "patch" "-p1" "<" "${CMAKE_CURRENT_SOURCE_DIR}/src/trampoline.patch"
-    COMMAND ${QEMU_FLATPAK_PATCH}
+    PATCH_COMMAND "patch" "-p1" "<" "${CMAKE_CURRENT_SOURCE_DIR}/runtime.patch"
 )
 
+# Get Full Library Path
+ExternalProject_Get_Property(qemu INSTALL_DIR)
+string(PREPEND QEMU_LIBRARY "${INSTALL_DIR}")
+
+# Link
+target_link_libraries(runtime "${QEMU_LIBRARY}")
+target_compile_definitions(trampoline-headers INTERFACE MCPI_HAS_QEMU)
+
 # Install
-function(install_runtime bin_dir legal_dir)
-    ExternalProject_Get_property(qemu BINARY_DIR)
-    install(PROGRAMS "${BINARY_DIR}/qemu-arm" DESTINATION "${bin_dir}" RENAME "runtime")
+if(DEFINED MCPI_LIB_DIR)
+    install(PROGRAMS "${QEMU_LIBRARY}" DESTINATION "${MCPI_LIB_DIR}")
     # License
-    ExternalProject_Get_property(qemu SOURCE_DIR)
-    install(FILES "${SOURCE_DIR}/COPYING" DESTINATION "${legal_dir}/qemu")
-endfunction()
+    ExternalProject_Get_Property(qemu SOURCE_DIR)
+    install(FILES "${SOURCE_DIR}/COPYING" DESTINATION "${MCPI_LEGAL_DIR}/qemu")
+endif()

qemu/runtime.patch

@@ -0,0 +1,71 @@
+--- a/linux-user/main.c
++++ b/linux-user/main.c
+@@ -671,7 +671,8 @@
+     return optind;
+ }
+
+-int main(int argc, char **argv, char **envp)
++#pragma GCC diagnostic ignored "-Wmissing-prototypes"
++int qemu_main(int argc, char **argv, char **envp)
+ {
+     struct target_pt_regs regs1, *regs = &regs1;
+     struct image_info info1, *info = &info1;
+--- a/linux-user/syscall.c
++++ b/linux-user/syscall.c
+@@ -9077,6 +9077,8 @@
+            int, __to_dfd, const char *, __to_pathname, unsigned int, flag)
+ #endif
+
++extern int trampoline_handle_syscall(int32_t num, uint32_t arg1, uint32_t arg2);
++
+ /* This is an internal helper for do_syscall so that it is easier
+  * to have a single return point, so that actions, such as logging
+  * of syscall results, can be performed.
+@@ -9101,6 +9103,10 @@
+ #endif
+     void *p;
+
++    if (trampoline_handle_syscall(num, arg1, arg2)) {
++        return 0;
++    }
++
+     switch(num) {
+     case TARGET_NR_exit:
+         /* In old applications this may be used to implement _exit(2).
+--- a/meson.build
++++ b/meson.build
+@@ -2470,7 +2470,6 @@
+ config_host_data.set('CONFIG_LINUX_MAGIC_H', cc.has_header('linux/magic.h'))
+ config_host_data.set('CONFIG_VALGRIND_H', cc.has_header('valgrind/valgrind.h'))
+ config_host_data.set('HAVE_BTRFS_H', cc.has_header('linux/btrfs.h'))
+-config_host_data.set('HAVE_DRM_H', cc.has_header('libdrm/drm.h'))
+ config_host_data.set('HAVE_PTY_H', cc.has_header('pty.h'))
+ config_host_data.set('HAVE_SYS_DISK_H', cc.has_header('sys/disk.h'))
+ config_host_data.set('HAVE_SYS_IOCCOM_H', cc.has_header('sys/ioccom.h'))
+@@ -4015,14 +4014,13 @@
+       exe_name += '-unsigned'
+     endif
+
+-    emulator = executable(exe_name, exe['sources'],
++    emulator = library(exe_name, exe['sources'],
+                install: true,
+                c_args: c_args,
+                dependencies: arch_deps + exe['dependencies'],
+                objects: lib.extract_all_objects(recursive: true),
+                link_depends: [block_syms, qemu_syms],
+-               link_args: link_args,
+-               win_subsystem: exe['win_subsystem'])
++               link_args: link_args)
+
+     if host_os == 'darwin'
+       icon = 'pc-bios/qemu.rsrc'
+@@ -4166,9 +4164,7 @@
+
+ subdir('scripts')
+ subdir('tools')
+-subdir('pc-bios')
+ subdir('docs')
+-subdir('tests')
+ if gtk.found()
+   subdir('po')
+ endif

qemu/src/trampoline.patch

@@ -1,57 +0,0 @@
---- a/linux-user/syscall.c
-+++ b/linux-user/syscall.c
-@@ -17,6 +17,8 @@
-  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
-  */
- #define _ATFILE_SOURCE
-+#include <dlfcn.h>
-+#include <trampoline/types.h>
- #include "qemu/osdep.h"
- #include "qemu/cutils.h"
- #include "qemu/path.h"
-@@ -9070,6 +9072,13 @@ _syscall5(int, sys_move_mount, int, __from_dfd, const char *, __from_pathname,
-            int, __to_dfd, const char *, __to_pathname, unsigned int, flag)
- #endif
- 
-+// g2h For Trampoline
-+static CPUState *_trampoline_g2h_cpu = NULL;
-+static void _trampoline_writer(uint32_t guest_addr, const void *data, uint32_t size) {
-+    void *out = g2h(_trampoline_g2h_cpu, guest_addr);
-+    memcpy(out, data, size);
-+}
-+
- /* This is an internal helper for do_syscall so that it is easier
-  * to have a single return point, so that actions, such as logging
-  * of syscall results, can be performed.
-@@ -9095,6 +9104,31 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
-     void *p;
- 
-     switch(num) {
-+    case TRAMPOLINE_SYSCALL: {
-+        // Load Trampoline
-+        static trampoline_t _trampoline = NULL;
-+        if (_trampoline == NULL) {
-+            // Open Library
-+            void *_trampoline_handle = dlopen("libmedia-layer-trampoline.so", RTLD_NOW);
-+            // Load Function
-+            if (_trampoline_handle != NULL) {
-+                _trampoline = dlsym(_trampoline_handle, "trampoline");
-+            }
-+        }
-+        if (_trampoline == NULL) {
-+            // Failed To Load
-+            qemu_log("Unable To Load Media Layer Trampoline: %s\n", dlerror());
-+            return -TARGET_ENOSYS;
-+        }
-+        // Call Trampoline
-+        _trampoline_g2h_cpu = cpu;
-+        	uint32_t _trampoline_id = arg1;
-+        	__attribute__((unused)) uint32_t _trampoline_length = arg2;
-+        	const unsigned char *_trampoline_args = g2h(cpu, arg3);
-+        uint32_t _trampoline_ret = _trampoline(_trampoline_writer, _trampoline_id, _trampoline_args);
-+        *(uint32_t *) _trampoline_args = _trampoline_ret;
-+        return 0;
-+    }
-     case TARGET_NR_exit:
-         /* In old applications this may be used to implement _exit(2).
-            However in threaded applications it is used for thread termination,

src/log.h

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

src/main.cpp

@@ -0,0 +1,25 @@
+#include "log.h"
+#include "pipe/main.h"
+#ifdef MCPI_HAS_QEMU
+#include "syscall/main.h"
+#endif
+
+// Main
+int main(int argc, char *argv[]) {
+    // Check Arguments
+    if (argc < 2) {
+        ERR("Invalid Arguments");
+    }
+    // Update Arguments
+    argc--;
+    argv++;
+    // Create Implementation
+    Implementation *impl = new PipeImplementation;
+#ifdef MCPI_HAS_QEMU
+    if (getenv(MCPI_USE_PIPE_TRAMPOLINE_ENV) == nullptr) {
+        delete impl;
+        impl = new SyscallImplementation;
+    }
+#endif
+    return impl->main(argc, argv);
+}

src/main.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include <cstdint>
+
+#include "trampoline.h"
+
+struct Implementation {
+    virtual ~Implementation() = default;
+    virtual int main(int argc, char *argv[]) = 0;
+    virtual void memory_writer(uint32_t guest_addr, const void *data, uint32_t size) const = 0;
+    Trampoline trampoline;
+};

src/pipe/loop.cpp

@@ -5,51 +5,50 @@
 
 #include <trampoline/types.h>
 
-#include "loop.h"
-
-#include "log.h"
-#include "trampoline.h"
-#include "memory.h"
+#include "../log.h"
+#include "main.h"
 
 // Setup Pipes
 #define PIPE_READ 0
 #define PIPE_WRITE 1
-static int arguments_pipe[2];
-static int return_value_pipe[2];
 static void safe_pipe(int *out) {
-    int ret = pipe(out);
+    const int ret = pipe(out);
     if (ret != 0) {
         ERR("Unable To Create Pipe: %s", strerror(errno));
     }
 }
-void create_pipes() {
+void PipeImplementation::init() {
+    setenv(MCPI_USE_PIPE_TRAMPOLINE_ENV, "", 1);
     safe_pipe(arguments_pipe);
     safe_pipe(return_value_pipe);
 }
 
-// Guest
-void init_pipe_guest() {
+// Parent
+void PipeImplementation::init_parent() const {
     // Close Unneeded Pipes
     close(arguments_pipe[PIPE_READ]);
     close(return_value_pipe[PIPE_WRITE]);
     // Setup Environment
-    setenv(TRAMPOLINE_ARGUMENTS_PIPE_ENV, std::to_string(arguments_pipe[PIPE_WRITE]).c_str(), true);
-    setenv(TRAMPOLINE_RETURN_VALUE_PIPE_ENV, std::to_string(return_value_pipe[PIPE_READ]).c_str(), true);
+    setenv(_MCPI_TRAMPOLINE_ARGUMENTS_ENV, std::to_string(arguments_pipe[PIPE_WRITE]).c_str(), true);
+    setenv(_MCPI_TRAMPOLINE_RETURN_VALUE_ENV, std::to_string(return_value_pipe[PIPE_READ]).c_str(), true);
 }
 
-// Host
-void pipe_read_loop() {
+// Child
+void PipeImplementation::init_child() {
     // Close Unneeded Pipes
     close(arguments_pipe[PIPE_WRITE]);
     close(return_value_pipe[PIPE_READ]);
+    // Init Trampoline
+    trampoline.init(this);
+}
+void PipeImplementation::loop_child() const {
     // 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) {
-            ssize_t ret = read(arguments_pipe[PIPE_READ], args + position, cmd.length - position);
+            const ssize_t ret = read(arguments_pipe[PIPE_READ], args + position, cmd.length - position);
             if (ret == -1) {
                 ERR("Unable To Read Trampoline Arguments");
             } else {
@@ -58,7 +57,7 @@ void pipe_read_loop() {
         }
         uint32_t ret = trampoline(cmd.id, args);
         if (!cmd.allow_early_return) {
-            ssize_t ret2 = write(return_value_pipe[PIPE_WRITE], &ret, sizeof(uint32_t));
+            const ssize_t ret2 = write(return_value_pipe[PIPE_WRITE], &ret, sizeof(uint32_t));
             if (ret2 == -1) {
                 ERR("Unable To Write Trampoline Return Value");
             }

src/pipe/main.cpp

@@ -0,0 +1,46 @@
+#include <unistd.h>
+#include <cstring>
+#include <cerrno>
+#include <sys/wait.h>
+#include <linux/prctl.h>
+#include <sys/prctl.h>
+
+#include "../log.h"
+#ifdef MCPI_HAS_QEMU
+#include "../qemu/qemu.h"
+#endif
+#include "main.h"
+
+// Main
+int PipeImplementation::main(const int argc, char *argv[]) {
+    // Setup
+    init();
+    // Fork
+    const pid_t pid = fork();
+    if (pid == -1) {
+        ERR("Unable To Fork Process: %s", strerror(errno));
+    } else if (pid == 0) {
+        // Child
+
+        // Setup
+        setpgid(0, 0);
+        init_child();
+        // Read From Pipes
+        loop_child();
+        // Exit
+        return 0;
+    } else {
+        // Parent/Guest
+
+        // Setup
+        init_parent();
+        prctl(PR_SET_PTRACER, pid);
+        // Execute Program
+#ifdef MCPI_HAS_QEMU
+        return QEMU::run(argc, argv);
+#else
+        execvp(argv[0], (char *const *) argv);
+        ERR("Unable To Execute Program: %s: %s", argv[0], strerror(errno));
+#endif
+    }
+}

src/pipe/main.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <unistd.h>
+
+#include "../main.h"
+
+struct PipeImplementation final : Implementation {
+    int main(int argc, char *argv[]) override;
+    void memory_writer(uint32_t guest_addr, const void *data, uint32_t size) const override;
+private:
+    void init();
+    void init_child();
+    void init_parent() const;
+    void loop_child() const;
+    // Pipes
+    int arguments_pipe[2] = {}; // Send Trampoline Commands From Parent -> Child
+    int return_value_pipe[2] = {}; // Send Return Value From Child -> Parent
+    // PID
+    const pid_t guest_pid = getpid();
+};

src/pipe/memory.cpp

@@ -0,0 +1,30 @@
+#include <sys/uio.h>
+#include <cstring>
+#include <cerrno>
+
+#include "main.h"
+#include "../log.h"
+#ifdef MCPI_HAS_QEMU
+#include "../qemu/qemu.h"
+#endif
+
+// Write Memory To Parent/Guest
+void PipeImplementation::memory_writer(const uint32_t guest_addr, const void *data, const uint32_t size) const {
+    iovec local[1];
+    local[0].iov_base = (void *) data;
+    local[0].iov_len = size;
+    iovec remote[1];
+    void *fixed_guest_addr =
+#ifdef MCPI_HAS_QEMU
+        QEMU::guest_to_host(guest_addr)
+#else
+        (void *) (uint64_t) guest_addr
+#endif
+        ;
+    remote[0].iov_base = fixed_guest_addr;
+    remote[0].iov_len = size;
+    const ssize_t ret = process_vm_writev(guest_pid, local, 1, remote, 1, 0);
+    if (ret != size) {
+        ERR("Unable To Write Data: 0x%08x: %s", guest_addr, strerror(errno));
+    }
+}

src/qemu/qemu.cpp

@@ -0,0 +1,25 @@
+#include <unistd.h>
+#include <vector>
+
+#include <trampoline/types.h>
+
+#include "qemu.h"
+
+// Access QEMU's Memory
+void *QEMU::guest_to_host(const uint32_t guest_addr) {
+    return (void *) (uintptr_t) (guest_addr + QEMU_GUEST_BASE);;
+}
+
+// Run
+#define _TO_STRING(x) #x
+#define TO_STRING(x) _TO_STRING(x)
+int QEMU::run(const int argc, char **argv) {
+    // Get Arguments
+    std::vector<const char *> new_args;
+    new_args.push_back("qemu");
+    new_args.push_back("-B");
+    new_args.push_back(TO_STRING(QEMU_GUEST_BASE));
+    new_args.insert(new_args.end(), argv, argv + argc);
+    // Run
+    return qemu_main(int(new_args.size()), (char **) new_args.data(), environ);
+}

src/qemu/qemu.h

@@ -0,0 +1,23 @@
+#pragma once
+
+#include <cstdint>
+
+#ifndef MCPI_HAS_QEMU
+#error "QEMU Is Not Present!"
+#endif
+
+// QEMU API
+extern "C" {
+    // Called By Patched QEMU
+    int trampoline_handle_syscall(int32_t num, uint32_t arg1, uint32_t arg2);
+    // Main
+    int qemu_main(int argc, char **argv, char **envp);
+}
+
+// Utility Functions
+namespace QEMU {
+    // Memory
+    void *guest_to_host(uint32_t guest_addr);
+    // Run
+    int run(int argc, char **argv);
+}

src/syscall/handler.cpp

@@ -0,0 +1,21 @@
+#include <trampoline/types.h>
+
+#include "../qemu/qemu.h"
+#include "main.h"
+
+// Handle Syscall
+int trampoline_handle_syscall(const int32_t num, const uint32_t arg1, uint32_t arg2) {
+    // Check Syscall
+    if (num != TRAMPOLINE_SYSCALL) {
+        return 0;
+    }
+    // Run
+    SyscallImplementation::instance->handle_syscall(arg1, arg2);
+    return 1;
+}
+void SyscallImplementation::handle_syscall(const uint32_t arg1, const uint32_t arg2) const {
+    const uint32_t id = arg1;
+    const unsigned char *args = (const unsigned char *) QEMU::guest_to_host(arg2);
+    const uint32_t ret = trampoline(id, args);
+    *(uint32_t *) args = ret;
+}

src/syscall/main.cpp

@@ -0,0 +1,20 @@
+#include <cstdlib>
+#include <cstring>
+
+#include "main.h"
+#include "../qemu/qemu.h"
+
+// Main
+SyscallImplementation *SyscallImplementation::instance = nullptr;
+int SyscallImplementation::main(const int argc, char *argv[]) {
+    instance = this;
+    // Setup
+    trampoline.init(this);
+    // Run
+    return QEMU::run(argc, argv);
+}
+
+// Read From QEMU's Memory
+void SyscallImplementation::memory_writer(const uint32_t guest_addr, const void *data, const uint32_t size) const {
+    memcpy(QEMU::guest_to_host(guest_addr), data, size);
+}

src/syscall/main.h

@@ -0,0 +1,10 @@
+#pragma once
+
+#include "../main.h"
+
+struct SyscallImplementation final : Implementation {
+    int main(int argc, char *argv[]) override;
+    void memory_writer(uint32_t guest_addr, const void *data, uint32_t size) const override;
+    void handle_syscall(uint32_t arg1, uint32_t arg2) const;
+    static SyscallImplementation *instance;
+};

src/trampoline.cpp

@@ -3,21 +3,22 @@
 #include "trampoline.h"
 #include "memory.h"
 #include "log.h"
+#include "main.h"
+
+// Memory Writer
+const Implementation *stored_impl = nullptr;
+static void memory_writer(const uint32_t guest_addr, const void *data, const uint32_t size) {
+    stored_impl->memory_writer(guest_addr, data, size);
+}
 
 // Run Trampoline
-typedef uint32_t (*trampoline_t)(typeof(memory_writer) *writer, uint32_t id, const unsigned char *args);
-static trampoline_t func = nullptr;
-uint32_t trampoline(uint32_t id, const unsigned char *args) {
+uint32_t Trampoline::operator()(const uint32_t id, const unsigned char *args) const {
     return func(memory_writer, id, args);
 }
 
 // Init
-void init_trampoline() {
-    static bool is_setup = false;
-    if (is_setup) {
-        return;
-    }
-    is_setup = true;
+void Trampoline::init(const Implementation *impl) {
+    stored_impl = impl;
     // Open Library
     void *handle = dlopen("libmedia-layer-trampoline.so", RTLD_NOW);
     if (handle != nullptr) {

src/trampoline.h

@@ -0,0 +1,11 @@
+#pragma once
+
+#include <trampoline/types.h>
+
+struct Implementation;
+struct Trampoline {
+    void init(const Implementation *impl);
+    uint32_t operator()(uint32_t id, const unsigned char *args) const;
+private:
+    trampoline_t func = nullptr;
+};