Add the ability to override the Unity's boot.config file path (#59)

README.md

@@ -133,10 +133,11 @@ All Doorstop arguments start with `--doorstop-` and always contain an argument.
 * `string` = any sequence of characters and numbers. Wrap into `"`s if the string contains spaces
 
 | Argument                                          | Description                                                                                          |
-| ------------------------------------------------- | ---------------------------------------------------------------------------------------------------- |
+| ------------------------------------------------- |------------------------------------------------------------------------------------------------------|
 | `--doorstop-enabled bool`                         | Enable or disable Doorstop.                                                                          |
 | `--doorstop-redirect-output-log bool`             | *Only on Windows*: If `true` Unity's output log is redirected to `<current folder>\output_log.txt`   |
 | `--doorstop-target-assembly string`               | Path to the assembly to load and execute.                                                            |
+| `--doorstop-boot-config-override string`          | Overrides the boot.config file path.                                                                 |
 | `--doorstop-mono-dll-search-path-override string` | Overrides default Mono DLL search path                                                               |
 | `--doorstop-mono-debug-enabled bool`              | If true, Mono debugger server will be enabled                                                        |
 | `--doorstop-mono-debug-suspend bool`              | Whether to suspend the game execution until the debugger is attached.                                |

assets/nix/run.sh

@@ -25,6 +25,9 @@ enabled="1"
 # NOTE: The entrypoint must be of format `static void Doorstop.Entrypoint.Start()`
 target_assembly="Doorstop.dll"
 
+# Overrides the default boot.config file path
+boot_config_override=
+
 # If enabled, DOORSTOP_DISABLE env var value is ignored
 # USE THIS ONLY WHEN ASKED TO OR YOU KNOW WHAT THIS MEANS
 ignore_disable_switch="0"
@@ -197,6 +200,10 @@ while :; do
             target_assembly="$2"
             shift
         ;;
+        --doorstop-boot-config-override)
+            boot_config_override="$2"
+            shift
+        ;;
         --doorstop-mono-dll-search-path-override)
             dll_search_path_override="$2"
             shift
@@ -234,6 +241,7 @@ done
 # Move variables to environment
 export DOORSTOP_ENABLED="$enabled"
 export DOORSTOP_TARGET_ASSEMBLY="$target_assembly"
+export DOORSTOP_BOOT_CONFIG_OVERRIDE="$boot_config_override"
 export DOORSTOP_IGNORE_DISABLED_ENV="$ignore_disable_switch"
 export DOORSTOP_MONO_DLL_SEARCH_PATH_OVERRIDE="$dll_search_path_override"
 export DOORSTOP_MONO_DEBUG_ENABLED="$debug_enable"

assets/windows/doorstop_config.ini

@@ -11,6 +11,9 @@ target_assembly=Doorstop.dll
 # If true, Unity's output log is redirected to <current folder>\output_log.txt
 redirect_output_log=false
 
+# Overrides the default boot.config file path
+boot_config_override=
+
 # If enabled, DOORSTOP_DISABLE env var value is ignored
 # USE THIS ONLY WHEN ASKED TO OR YOU KNOW WHAT THIS MEANS
 ignore_disable_switch=false

src/bootstrap.c

@@ -267,14 +267,14 @@ void il2cpp_doorstop_bootstrap() {
     strcat(app_paths_env, config.clr_corlib_dir);
     strcat(app_paths_env, PATH_SEP);
     strcat(app_paths_env, target_dir);
-    char *app_paths_env_n = narrow(app_paths_env);
+    const char *app_paths_env_n = narrow(app_paths_env);
 
     LOG("App path: %s", app_path);
     LOG("Target dir: %s", target_dir);
     LOG("Target name: %s", target_name);
     LOG("APP_PATHS: %s", app_paths_env);
 
-    char *props = "APP_PATHS";
+    const char *props = "APP_PATHS";
 
     setenv(TEXT("DOORSTOP_INITIALIZED"), TEXT("TRUE"), TRUE);
     setenv(TEXT("DOORSTOP_INVOKE_DLL_PATH"), config.target_assembly, TRUE);
@@ -293,7 +293,8 @@ void il2cpp_doorstop_bootstrap() {
 
     void (*startup)() = NULL;
     result = coreclr.create_delegate(host, domain_id, target_name_n,
-                                     "Doorstop.Entrypoint", "Start", &startup);
+                                     "Doorstop.Entrypoint", "Start",
+                                     (void **)&startup);
     if (result != 0) {
         LOG("Failed to get entrypoint delegate: 0x%08x", result);
         return;

src/config/common.c

@@ -11,6 +11,7 @@ void cleanup_config() {
     }
 
     FREE_NON_NULL(config.target_assembly);
+    FREE_NON_NULL(config.boot_config_override);
     FREE_NON_NULL(config.mono_dll_search_path_override);
     FREE_NON_NULL(config.clr_corlib_dir);
     FREE_NON_NULL(config.clr_runtime_coreclr_path);
@@ -27,6 +28,7 @@ void init_config_defaults() {
     config.mono_debug_suspend = FALSE;
     config.mono_debug_address = NULL;
     config.target_assembly = NULL;
+    config.boot_config_override = NULL;
     config.mono_dll_search_path_override = NULL;
     config.clr_corlib_dir = NULL;
     config.clr_runtime_coreclr_path = NULL;

src/config/config.h

@@ -35,6 +35,12 @@ typedef struct {
      */
     char_t *target_assembly;
 
+    /**
+     * @brief Path to a custom boot.config file to use. If enabled, this file
+     * takes precedence over the default one in the Data folder.
+     */
+    char_t *boot_config_override;
+
     /**
      * @brief Path to use as the main DLL search path. If enabled, this folder
      * takes precedence over the default Managed folder.

src/nix/config.c

@@ -10,7 +10,7 @@ void get_env_bool(const char_t *name, bool_t *target) {
     }
 }
 
-void try_get_env(const char_t *name, const char_t *def, char_t **target) {
+void try_get_env(const char_t *name, char_t *def, char_t **target) {
     char_t *value = getenv(name);
     if (value != NULL && strlen(value) > 0) {
         *target = strdup(value);
@@ -37,6 +37,7 @@ void load_config() {
     try_get_env("DOORSTOP_MONO_DEBUG_ADDRESS", TEXT("127.0.0.1:10000"),
                 &config.mono_debug_address);
     get_env_path("DOORSTOP_TARGET_ASSEMBLY", &config.target_assembly);
+    get_env_path("DOORSTOP_BOOT_CONFIG_OVERRIDE", &config.boot_config_override);
     try_get_env("DOORSTOP_MONO_DLL_SEARCH_PATH_OVERRIDE", TEXT(""),
                 &config.mono_dll_search_path_override);
     get_env_path("DOORSTOP_CLR_RUNTIME_CORECLR_PATH",

src/nix/entrypoint.c

@@ -59,6 +59,31 @@ int fclose_hook(FILE *stream) {
     return fclose(stream);
 }
 
+char_t *default_boot_config_path = NULL;
+#if !defined(__APPLE__)
+FILE *fopen64_hook(char *filename, char *mode) {
+    char *actual_file_name = filename;
+
+    if (strcmp(filename, default_boot_config_path) == 0) {
+        actual_file_name = config.boot_config_override;
+        LOG("Overriding boot.config to %s", actual_file_name);
+    }
+
+    return fopen64(actual_file_name, mode);
+}
+#endif
+
+FILE *fopen_hook(char *filename, char *mode) {
+    char *actual_file_name = filename;
+
+    if (strcmp(filename, default_boot_config_path) == 0) {
+        actual_file_name = config.boot_config_override;
+        LOG("Overriding boot.config to %s", actual_file_name);
+    }
+
+    return fopen(actual_file_name, mode);
+}
+
 int dup2_hook(int od, int nd) {
     // Newer versions of Unity redirect stdout to player.log, we don't want
     // that
@@ -80,7 +105,8 @@ __attribute__((constructor)) void doorstop_ctor() {
 
     void *unity_player = plthook_handle_by_name("UnityPlayer");
 
-    if (unity_player && PLTHOOK_OPEN_BY_HANDLE_OR_ADDRESS(&hook, unity_player) == 0) {
+    if (unity_player &&
+        PLTHOOK_OPEN_BY_HANDLE_OR_ADDRESS(&hook, unity_player) == 0) {
         LOG("Found UnityPlayer, hooking into it instead");
     } else if (plthook_open(&hook, NULL) != 0) {
         LOG("Failed to open current process PLT! Cannot run Doorstop! "
@@ -94,6 +120,31 @@ __attribute__((constructor)) void doorstop_ctor() {
         printf("Failed to hook dlsym, ignoring it. Error: %s\n",
                plthook_error());
 
+    if (config.boot_config_override) {
+        if (file_exists(config.boot_config_override)) {
+            default_boot_config_path = calloc(MAX_PATH, sizeof(char_t));
+            memset(default_boot_config_path, 0, MAX_PATH * sizeof(char_t));
+            strcat(default_boot_config_path, get_working_dir());
+            strcat(default_boot_config_path, TEXT("/"));
+            strcat(default_boot_config_path,
+                   get_file_name(program_path(), FALSE));
+            strcat(default_boot_config_path, TEXT("_Data/boot.config"));
+
+#if !defined(__APPLE__)
+            if (plthook_replace(hook, "fopen64", &fopen64_hook, NULL) != 0)
+                printf("Failed to hook fopen64, ignoring it. Error: %s\n",
+                       plthook_error());
+#endif
+            if (plthook_replace(hook, "fopen", &fopen_hook, NULL) != 0)
+                printf("Failed to hook fopen, ignoring it. Error: %s\n",
+                       plthook_error());
+        } else {
+            LOG("The boot.config file won't be overriden because the provided "
+                "one does not exist: %s",
+                config.boot_config_override);
+        }
+    }
+
     if (plthook_replace(hook, "fclose", &fclose_hook, NULL) != 0)
         printf("Failed to hook fclose, ignoring it. Error: %s\n",
                plthook_error());

src/util/util.h

@@ -24,7 +24,9 @@ typedef int bool_t;
 
 #define TRUE 1
 #define FALSE 0
+#ifndef NULL
 #define NULL 0
+#endif
 
 #define TEXT(text) text
 

src/windows/config.c

@@ -71,6 +71,8 @@ static inline void init_config_file() {
                    TEXT("false"), &config.redirect_output_log);
     load_path_file(config_path, TEXT("General"), TEXT("target_assembly"),
                    DEFAULT_TARGET_ASSEMBLY, &config.target_assembly);
+    load_path_file(config_path, TEXT("General"), TEXT("boot_config_override"),
+                   NULL, &config.boot_config_override);
 
     load_str_file(config_path, TEXT("UnityMono"),
                   TEXT("dll_search_path_override"), TEXT(""),
@@ -144,6 +146,8 @@ static inline void init_cmd_args() {
                   config.redirect_output_log, load_bool_argv);
         PARSE_ARG(TEXT("--doorstop-target-assembly"), config.target_assembly,
                   load_path_argv);
+        PARSE_ARG(TEXT("--doorstop-boot-config-override"),
+                  config.boot_config_override, load_path_argv);
 
         PARSE_ARG(TEXT("--doorstop-mono-dll-search-path-override"),
                   config.mono_dll_search_path_override, load_path_argv);

src/windows/entrypoint.c

@@ -41,6 +41,8 @@ bool_t fix_cwd() {
 #define LOG_FILE_CMD_END L"\\output_log.txt\""
 #define LOG_FILE_CMD_END_LEN STR_LEN(LOG_FILE_CMD_END)
 
+char_t *default_boot_config_path = NULL;
+
 char_t *new_cmdline_args = NULL;
 char *new_cmdline_args_narrow = NULL;
 
@@ -63,6 +65,70 @@ bool_t WINAPI close_handle_hook(void *handle) {
     return CloseHandle(handle);
 }
 
+HANDLE WINAPI create_file_hook(LPCWSTR lpFileName, DWORD dwDesiredAccess,
+                               DWORD dwShareMode,
+                               LPSECURITY_ATTRIBUTES lpSecurityAttributes,
+                               DWORD dwCreationDisposition,
+                               DWORD dwFlagsAndAttributes,
+                               HANDLE hTemplateFile) {
+    LPCWSTR actual_file_name = lpFileName;
+
+    char_t *normalised_path = calloc(strlen(lpFileName) + 1, sizeof(char_t));
+    memset(normalised_path, 0, (strlen(lpFileName) + 1) * sizeof(char_t));
+    strcpy(normalised_path, lpFileName);
+    for (size_t i = 0; i < strlen(normalised_path); i++) {
+        if (normalised_path[i] == L'/') {
+            normalised_path[i] = L'\\';
+        }
+    }
+
+    if (strcmpi(normalised_path, default_boot_config_path) == 0) {
+        actual_file_name = config.boot_config_override;
+        LOG("Overriding boot.config to %s", actual_file_name);
+    }
+
+    free(normalised_path);
+
+    return CreateFileW(actual_file_name, dwDesiredAccess, dwShareMode,
+                       lpSecurityAttributes, dwCreationDisposition,
+                       dwFlagsAndAttributes, hTemplateFile);
+}
+
+HANDLE WINAPI create_file_hook_narrow(
+    void *lpFileName, DWORD dwDesiredAccess, DWORD dwShareMode,
+    LPSECURITY_ATTRIBUTES lpSecurityAttributes, DWORD dwCreationDisposition,
+    DWORD dwFlagsAndAttributes, HANDLE hTemplateFile) {
+    void *actual_file_name = lpFileName;
+
+    char_t *widened_filename = widen(lpFileName);
+    char_t *normalised_path =
+        calloc(strlen(widened_filename) + 1, sizeof(char_t));
+    memset(normalised_path, 0, (strlen(widened_filename) + 1) * sizeof(char_t));
+    strcpy(normalised_path, widened_filename);
+    free(widened_filename);
+
+    for (size_t i = 0; i < strlen(normalised_path); i++) {
+        if (normalised_path[i] == L'/') {
+            normalised_path[i] = L'\\';
+        }
+    }
+
+    if (strcmpi(normalised_path, default_boot_config_path) == 0) {
+        char *narrowed_boot_config_override =
+            narrow(config.boot_config_override);
+        memcpy(actual_file_name, narrowed_boot_config_override,
+               strlen(config.boot_config_override));
+        free(narrowed_boot_config_override);
+        LOG("Overriding boot.config to %s", actual_file_name);
+    }
+
+    free(normalised_path);
+
+    return CreateFileA(actual_file_name, dwDesiredAccess, dwShareMode,
+                       lpSecurityAttributes, dwCreationDisposition,
+                       dwFlagsAndAttributes, hTemplateFile);
+}
+
 void capture_mono_path(void *handle) {
     char_t *result;
     get_module_path(handle, &result, NULL, 0);
@@ -146,6 +212,25 @@ void inject(DoorstopPaths const *paths) {
 
     HOOK_SYS(target_module, GetProcAddress, get_proc_address_detour);
     HOOK_SYS(target_module, CloseHandle, close_handle_hook);
+    if (config.boot_config_override) {
+        if (file_exists(config.boot_config_override)) {
+            default_boot_config_path = calloc(MAX_PATH, sizeof(char_t));
+            memset(default_boot_config_path, 0, MAX_PATH * sizeof(char_t));
+            strcat(default_boot_config_path, get_working_dir());
+            strcat(default_boot_config_path, TEXT("\\"));
+            strcat(default_boot_config_path,
+                   get_file_name(program_path(), FALSE));
+            strcat(default_boot_config_path, TEXT("_Data\\boot.config"));
+
+            HOOK_SYS(target_module, CreateFileW, create_file_hook);
+            HOOK_SYS(target_module, CreateFileA, create_file_hook_narrow);
+        } else {
+            LOG("The boot.config file won't be overriden because the provided "
+                "one does not exist: %s",
+                config.boot_config_override);
+        }
+    }
+
     HOOK_SYS(app_module, GetCommandLineW, get_command_line_hook);
     HOOK_SYS(app_module, GetCommandLineA, get_command_line_hook_narrow);