Kernel/LibC: Write cxx abi with proper locking

libc/icxxabi.cpp

@@ -1,37 +1,41 @@
-#include <icxxabi.h>
+#include <BAN/Assert.h>
+#include <stdint.h>
+#include <stddef.h>
 
 #define ATEXIT_MAX_FUNCS 128
 
 struct atexit_func_entry_t
 {
-	void (*destructor)(void*);
-	void* data;
+	void(*func)(void*);
+	void* arg;
 	void* dso_handle;
 };
 
 static atexit_func_entry_t __atexit_funcs[ATEXIT_MAX_FUNCS];
-static int __atexit_func_count = 0;
+static size_t __atexit_func_count = 0;
 
-int __cxa_atexit(void (*func)(void*), void* data, void* dso_handle)
+extern "C" int __cxa_atexit(void(*func)(void*), void* arg, void* dso_handle)
 {
 	if (__atexit_func_count >= ATEXIT_MAX_FUNCS)
-		return -1;;
-	__atexit_funcs[__atexit_func_count].destructor = func;
-	__atexit_funcs[__atexit_func_count].data = data;
-	__atexit_funcs[__atexit_func_count].dso_handle = dso_handle;
-	__atexit_func_count++;
+		return -1;
+	auto& atexit_func = __atexit_funcs[__atexit_func_count++];
+	atexit_func.func = func;
+	atexit_func.arg = arg;
+	atexit_func.dso_handle = dso_handle;
 	return 0;
 };
 
-void __cxa_finalize(void* func)
+extern "C" void __cxa_finalize(void* f)
 {
-	for (int i = __atexit_func_count - 1; i >= 0; i--)
+	for (size_t i = __atexit_func_count; i > 0; i--)
 	{
-		if (func && func != __atexit_funcs[i].destructor)
+		auto& atexit_func = __atexit_funcs[i - 1];
+		if (atexit_func.func == nullptr)
 			continue;
-		if (__atexit_funcs[i].destructor == nullptr)
-			continue;
-		__atexit_funcs[i].destructor(__atexit_funcs[i].data);
-		__atexit_funcs[i].destructor = nullptr;
+		if (f == nullptr || f == atexit_func.func)
+		{
+			atexit_func.func(atexit_func.arg);
+			atexit_func.func = nullptr;
+		}
 	}
-}
+};