Return as a borrowed pointer and cache the wrapper in quickjs

bindings/gumjs/gumquickprocess.c

@@ -110,6 +110,8 @@ static void gum_quick_exception_handler_free (
 static gboolean gum_quick_exception_handler_on_exception (
     GumExceptionDetails * details, GumQuickExceptionHandler * handler);
 
+static void gumjs_free_main_module (GumQuickProcess * self);
+
 static const JSCFunctionListEntry gumjs_process_entries[] =
 {
   JS_PROP_STRING_DEF ("arch", GUM_SCRIPT_ARCH, JS_PROP_C_W_E),
@@ -144,6 +146,7 @@ _gum_quick_process_init (GumQuickProcess * self,
 
   self->module = module;
   self->core = core;
+  self->main_module = JS_UNINITIALIZED;
 
   _gum_quick_core_store_module_data (core, "process", self);
 
@@ -164,17 +167,27 @@ _gum_quick_process_init (GumQuickProcess * self,
 void
 _gum_quick_process_flush (GumQuickProcess * self)
 {
-  g_clear_pointer (&self->main_module, gum_module_details_free);
+  gumjs_free_main_module (self);
   g_clear_pointer (&self->exception_handler, gum_quick_exception_handler_free);
 }
 
 void
 _gum_quick_process_dispose (GumQuickProcess * self)
 {
-  g_clear_pointer (&self->main_module, gum_module_details_free);
+  gumjs_free_main_module (self);
   g_clear_pointer (&self->exception_handler, gum_quick_exception_handler_free);
 }
 
+static void
+gumjs_free_main_module (GumQuickProcess * self)
+{
+  if (JS_IsUninitialized (self->main_module))
+    return;
+
+  JS_FreeValue (self->core->ctx, self->main_module);
+  self->main_module = JS_UNINITIALIZED;
+}
+
 void
 _gum_quick_process_finalize (GumQuickProcess * self)
 {
@@ -192,10 +205,13 @@ GUMJS_DEFINE_GETTER (gumjs_process_get_main_module)
 
   self = gumjs_get_parent_module (core);
 
-  if (self->main_module == NULL)
-    self->main_module = gum_process_get_main_module ();
+  if (JS_IsUninitialized (self->main_module))
+  {
+    const GumModuleDetails * main_details  = gum_process_get_main_module ();
+    self->main_module = _gum_quick_module_new (ctx, main_details, self->module);
+  }
 
-  return _gum_quick_module_new (ctx, self->main_module, self->module);
+  return JS_DupValue (ctx, self->main_module);
 }
 
 GUMJS_DEFINE_FUNCTION (gumjs_process_get_current_dir)

bindings/gumjs/gumquickprocess.h

@@ -23,7 +23,7 @@ struct _GumQuickProcess
   GumQuickCore * core;
 
   GumQuickExceptionHandler * exception_handler;
-  GumModuleDetails * main_module;
+  JSValue main_module;
 };
 
 G_GNUC_INTERNAL void _gum_quick_process_init (GumQuickProcess * self,

bindings/gumjs/gumv8process.cpp

@@ -160,14 +160,12 @@ _gum_v8_process_realize (GumV8Process * self)
 void
 _gum_v8_process_flush (GumV8Process * self)
 {
-  g_clear_pointer (&self->main_module, gum_module_details_free);
   g_clear_pointer (&self->exception_handler, gum_v8_exception_handler_free);
 }
 
 void
 _gum_v8_process_dispose (GumV8Process * self)
 {
-  g_clear_pointer (&self->main_module, gum_module_details_free);
   g_clear_pointer (&self->exception_handler, gum_v8_exception_handler_free);
 }
 
@@ -179,11 +177,11 @@ _gum_v8_process_finalize (GumV8Process * self)
 GUMJS_DEFINE_GETTER (gumjs_process_get_main_module)
 {
   auto self = module;
+  const GumModuleDetails * main_module;
 
-  if (self->main_module == NULL)
-    self->main_module = gum_process_get_main_module ();
+  main_module = gum_process_get_main_module ();
 
-  info.GetReturnValue ().Set (_gum_v8_module_value_new (self->main_module,
+  info.GetReturnValue ().Set (_gum_v8_module_value_new (main_module,
       self->module));
 }
 

bindings/gumjs/gumv8process.h

@@ -10,8 +10,6 @@
 #include "gumv8core.h"
 #include "gumv8module.h"
 
-#include <gum/gumprocess.h>
-
 struct GumV8ExceptionHandler;
 
 struct GumV8Process
@@ -20,7 +18,6 @@ struct GumV8Process
   GumV8Core * core;
 
   GumV8ExceptionHandler * exception_handler;
-  GumModuleDetails * main_module;
 };
 
 G_GNUC_INTERNAL void _gum_v8_process_init (GumV8Process * self,

gum/gumprocess.c

@@ -6,6 +6,7 @@
 
 #include "gumprocess-priv.h"
 
+#include "gum-init.h"
 #include "gumcloak.h"
 
 typedef struct _GumEmitThreadsContext GumEmitThreadsContext;
@@ -48,6 +49,7 @@ struct _GumResolveSymbolContext
 
 static gboolean gum_emit_thread_if_not_cloaked (
     const GumThreadDetails * details, gpointer user_data);
+static void gum_deinit_main_module (void);
 static gboolean gum_try_resolve_module_pointer_from (
     const GumModuleDetails * details, gpointer user_data);
 static gboolean gum_emit_module_if_not_cloaked (
@@ -146,6 +148,37 @@ gum_emit_thread_if_not_cloaked (const GumThreadDetails * details,
   return ctx->func (details, ctx->user_data);
 }
 
+/**
+ * gum_process_get_main_module:
+ *
+ * Returns the details of the module representing the main executable
+ * of the process.
+ */
+const GumModuleDetails *
+gum_process_get_main_module (void)
+{
+  static gsize cached_result = 0;
+
+  if (g_once_init_enter (&cached_result))
+  {
+    GumModuleDetails * result;
+
+    gum_process_enumerate_modules (_gum_process_match_main_module, &result);
+
+    _gum_register_destructor (gum_deinit_main_module);
+
+    g_once_init_leave (&cached_result, GPOINTER_TO_SIZE (result) + 1);
+  }
+
+  return GSIZE_TO_POINTER (cached_result) - 1;
+}
+
+static void
+gum_deinit_main_module (void)
+{
+  gum_module_details_free ((GumModuleDetails *) gum_process_get_main_module ());
+}
+
 /**
  * gum_process_resolve_module_pointer:
  * @ptr: memory location potentially belonging to a module
@@ -214,22 +247,6 @@ gum_process_enumerate_modules (GumFoundModuleFunc func,
   _gum_process_enumerate_modules (gum_emit_module_if_not_cloaked, &ctx);
 }
 
-/**
- * gum_process_get_main_module:
- *
- * Returns a copy of the details of the module representing the main executable
- * of the process. Result must be freed with gum_module_details_free ();
- */
-GumModuleDetails *
-gum_process_get_main_module (void)
-{
-  GumModuleDetails * result;
-
-  gum_process_enumerate_modules (_gum_process_match_main_module, &result);
-
-  return result;
-}
-
 static gboolean
 gum_emit_module_if_not_cloaked (const GumModuleDetails * details,
                                 gpointer user_data)

gum/gumprocess.h

@@ -205,11 +205,11 @@ GUM_API gboolean gum_process_modify_thread (GumThreadId thread_id,
     GumModifyThreadFunc func, gpointer user_data, GumModifyThreadFlags flags);
 GUM_API void gum_process_enumerate_threads (GumFoundThreadFunc func,
     gpointer user_data);
+GUM_API const GumModuleDetails * gum_process_get_main_module (void);
 GUM_API gboolean gum_process_resolve_module_pointer (gconstpointer ptr,
     gchar ** path, GumMemoryRange * range);
 GUM_API void gum_process_enumerate_modules (GumFoundModuleFunc func,
     gpointer user_data);
-GUM_API GumModuleDetails * gum_process_get_main_module (void);
 GUM_API void gum_process_enumerate_ranges (GumPageProtection prot,
     GumFoundRangeFunc func, gpointer user_data);
 GUM_API void gum_process_enumerate_malloc_ranges (