Tweak Loading

launcher/src/bootstrap.cpp

@@ -103,28 +103,20 @@ void bootstrap() {
 
     // Fix MCPI Dependencies
     char new_mcpi_exe_path[] = MCPI_PATCHED_DIR "/XXXXXX";
+    std::string linker;
     {
         // Log
         DEBUG("Patching ELF Dependencies...");
 
         // Find Linker
-        char *linker = nullptr;
-        // Select Linker
+        linker = "/lib/ld-linux-armhf.so.3";
 #ifdef MCPI_USE_PREBUILT_ARMHF_TOOLCHAIN
         // Use ARM Sysroot Linker
-        safe_asprintf(&linker, "%s/sysroot/lib/ld-linux-armhf.so.3", binary_directory.c_str());
-#else
-        // Use Current Linker
-        linker = patch_get_interpreter();
+        linker = binary_directory + "/sysroot" + linker;
 #endif
 
         // Patch
-        patch_mcpi_elf_dependencies(resolved_path, new_mcpi_exe_path, linker);
-
-        // Free Linker Path
-        if (linker != nullptr) {
-            free(linker);
-        }
+        patch_mcpi_elf_dependencies(resolved_path, new_mcpi_exe_path);
 
         // Verify
         if (!starts_with(new_mcpi_exe_path, MCPI_PATCHED_DIR)) {
@@ -146,13 +138,11 @@ void bootstrap() {
     free(resolved_path);
 
     // Configure Library Search Path
+    std::string mcpi_ld_path = "";
     {
         // Log
         DEBUG("Setting Linker Search Paths...");
 
-        // Prepare
-        std::string mcpi_ld_path = "";
-
         // Library Search Path For ARM Components
         {
             // Add ARM Library Directory
@@ -173,19 +163,17 @@ void bootstrap() {
                     mcpi_ld_path += value;
                 }
             }
-
-            // Set
-            set_and_print_env(MCPI_LD_VARIABLE_PREFIX "LD_LIBRARY_PATH", mcpi_ld_path.c_str());
         }
     }
 
     // Configure Preloaded Objects
+    std::string mcpi_ld_preload;
     {
         // Log
         DEBUG("Locating Mods...");
 
         // ARM Components
-        bootstrap_mods(binary_directory);
+        mcpi_ld_preload = bootstrap_mods(binary_directory);
     }
 
     // Start Game
@@ -195,23 +183,18 @@ void bootstrap() {
     std::vector<std::string> args;
     // Non-ARM Systems Need QEMU
 #ifdef MCPI_USE_QEMU
-    args.insert(args.begin(), QEMU_BINARY);
+    args.push_back(QEMU_BINARY);
+    // Fix Bug
+    args.push_back("-B");
+    args.push_back("0x40000"); // Arbitary Value That Works On My System
 #endif
 
-    // Preserve Existing LD_* Variables
-#define preserve_variable(name) set_and_print_env(MCPI_ORIGINAL_LD_VARIABLE_PREFIX name, getenv(name))
-    for_each_special_environmental_variable(preserve_variable);
-    set_and_print_env(MCPI_ORIGINAL_LD_VARIABLES_PRESERVED_ENV, "1");
-    // Setup Environment
-    setup_exec_environment(1);
-
-    // Pass LD_* Variables Through QEMU
-#ifdef MCPI_USE_QEMU
-#define pass_variable_through_qemu(name) args.push_back("-E"); args.push_back(std::string(name) + "=" + getenv(name))
-    for_each_special_environmental_variable(pass_variable_through_qemu);
-    // Treat QEMU Itself As A Native Component
-    setup_exec_environment(0);
-#endif
+    // Setup Linker
+    args.push_back(linker);
+    args.push_back("--library-path");
+    args.push_back(mcpi_ld_path);
+    args.push_back("--preload");
+    args.push_back(mcpi_ld_preload);
 
     // Specify MCPI Binary
     args.push_back(new_mcpi_exe_path);

launcher/src/bootstrap.h

@@ -4,4 +4,4 @@
 
 void bootstrap();
 void copy_sdk(const std::string &binary_directory, bool log_with_debug);
-void bootstrap_mods(const std::string &binary_directory);
+std::string bootstrap_mods(const std::string &binary_directory);

launcher/src/mods.cpp

@@ -53,7 +53,7 @@ static void load(std::string &ld_preload, const std::string &folder) {
 
 // Bootstrap Mods
 #define SUBDIRECTORY_FOR_MODS "/mods/"
-void bootstrap_mods(const std::string &binary_directory) {
+std::string bootstrap_mods(const std::string &binary_directory) {
     // Prepare
     std::string preload = "";
 
@@ -81,6 +81,6 @@ void bootstrap_mods(const std::string &binary_directory) {
         }
     }
 
-    // Set
-    set_and_print_env(MCPI_LD_VARIABLE_PREFIX "LD_PRELOAD", preload.c_str());
+    // Return
+    return preload;
 }

launcher/src/patchelf.cpp

@@ -15,7 +15,7 @@ static void duplicate_mcpi_executable(char *new_path) {
     // Ensure Temporary Directory
     {
         // Check If It Exists
-        struct stat tmp_stat;
+        struct stat tmp_stat = {};
         int exists = stat(MCPI_PATCHED_DIR, &tmp_stat) != 0 ? 0 : S_ISDIR(tmp_stat.st_mode);
         if (!exists) {
             // Doesn't Exist
@@ -44,16 +44,13 @@ static const char *libraries_to_remove[] = {
 static const char *libraries_to_add[] = {
     "libmedia-layer-core.so"
 };
-void patch_mcpi_elf_dependencies(const char *original_path, char *new_path, const char *linker) {
+void patch_mcpi_elf_dependencies(const char *original_path, char *new_path) {
     // Duplicate MCPI executable into /tmp so it can be modified.
     duplicate_mcpi_executable(new_path);
 
     // Patch File
     {
         std::unique_ptr<LIEF::ELF::Binary> binary = LIEF::ELF::Parser::parse(original_path);
-        if (linker != NULL) {
-            binary->interpreter(linker);
-        }
         for (size_t i = 0; i < (sizeof (libraries_to_remove) / sizeof (const char *)); i++) {
             binary->remove_library(libraries_to_remove[i]);
         }
@@ -70,25 +67,3 @@ void patch_mcpi_elf_dependencies(const char *original_path, char *new_path, cons
         ERR("Unable To Set File Permissions: %s: %s", new_path, strerror(errno));
     }
 }
-
-// Get Interpreter
-static int dl_iterate_callback(struct dl_phdr_info *info, __attribute__((unused)) size_t size, void *data) {
-    // Only Search Current Program
-    if (strcmp(info->dlpi_name, "") == 0) {
-        for (int i = 0; i < info->dlpi_phnum; i++) {
-            if (info->dlpi_phdr[i].p_type == PT_INTERP) {
-                // Callback
-                *(char **) data = (char *) (info->dlpi_addr + info->dlpi_phdr[i].p_vaddr);
-            }
-        }
-    }
-    return 0;
-}
-char *patch_get_interpreter() {
-    char *interpreter = NULL;
-    dl_iterate_phdr(dl_iterate_callback, &interpreter);
-    if (interpreter != NULL) {
-        interpreter = strdup(interpreter);
-    }
-    return interpreter;
-}

launcher/src/patchelf.h

@@ -6,8 +6,7 @@ extern "C" {
 
 #define MCPI_PATCHED_DIR "/tmp/.minecraft-pi-patched"
 
-void patch_mcpi_elf_dependencies(const char *original_path, char *new_path, const char *linker);
-char *patch_get_interpreter();
+void patch_mcpi_elf_dependencies(const char *original_path, char *new_path);
 
 #ifdef __cplusplus
 }

libreborn/include/libreborn/exec.h

@@ -20,13 +20,6 @@ extern "C" {
 void set_and_print_env(const char *name, const char *value);
 
 // Safe execvpe()
-#define MCPI_LD_VARIABLE_PREFIX "_MCPI_"
-#define MCPI_ORIGINAL_LD_VARIABLE_PREFIX MCPI_LD_VARIABLE_PREFIX "ORIGINAL_"
-#define MCPI_ORIGINAL_LD_VARIABLES_PRESERVED_ENV MCPI_ORIGINAL_LD_VARIABLE_PREFIX "PRESERVED"
-#define for_each_special_environmental_variable(handle) \
-    handle("LD_LIBRARY_PATH"); \
-    handle("LD_PRELOAD")
-void setup_exec_environment(int is_arm_component);
 __attribute__((noreturn)) void safe_execvpe(const char *const argv[], const char *const envp[]);
 
 // Debug Tag

libreborn/src/util/exec.c

@@ -19,17 +19,6 @@ void set_and_print_env(const char *name, const char *value) {
 }
 
 // Safe execvpe()
-#define handle_environmental_variable(var) \
-    { \
-        const char *full_var = is_arm_component ? MCPI_LD_VARIABLE_PREFIX var : MCPI_ORIGINAL_LD_VARIABLE_PREFIX var; \
-        const char *var_value = getenv(full_var); \
-        set_and_print_env(var, var_value); \
-    }
-void setup_exec_environment(int is_arm_component) {
-    if (is_arm_component || getenv(MCPI_ORIGINAL_LD_VARIABLES_PRESERVED_ENV) != NULL) {
-        for_each_special_environmental_variable(handle_environmental_variable);
-    }
-}
 __attribute__((noreturn)) void safe_execvpe(const char *const argv[], const char *const envp[]) {
     // Log
     DEBUG("Running Command:");
@@ -69,9 +58,6 @@ char *run_command(const char *const command[], int *exit_status, size_t *output_
         reborn_lock_debug(); // Lock Released On Process Exit
         dup2(reborn_get_debug_fd(), STDERR_FILENO);
 
-        // Setup Environment
-        setup_exec_environment(0);
-
         // Run
         safe_execvpe(command, (const char *const *) environ);
     } else {