lib: Add mlibc

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 42 insertions, 0 deletions

diff --git a/lib/mlibc/options/lsb/generic/dso_exit.cpp b/lib/mlibc/options/lsb/generic/dso_exit.cpp
new file mode 100644
index 0000000..b8b239d
--- /dev/null
+++ b/lib/mlibc/options/lsb/generic/dso_exit.cpp
@@ -0,0 +1,42 @@
+
+// for memcpy()
+#include <string.h>
+
+#include <bits/ensure.h>
+#include <mlibc/allocator.hpp>
+
+#include <frg/eternal.hpp>
+#include <frg/vector.hpp>
+
+struct ExitHandler {
+	void (*function)(void *);
+	void *argument;
+	void *dsoHandle;
+};
+
+using ExitQueue = frg::vector<ExitHandler, MemoryAllocator>;
+
+ExitQueue &getExitQueue() {
+	// use frg::eternal to prevent the compiler from scheduling the destructor
+	// by generating a call to __cxa_atexit().
+	static frg::eternal<ExitQueue> singleton(getAllocator());
+	return singleton.get();
+}
+
+extern "C" int __cxa_atexit(void (*function)(void *), void *argument, void *handle) {
+	ExitHandler handler;
+	handler.function = function;
+	handler.argument = argument;
+	handler.dsoHandle = handle;
+	getExitQueue().push(handler);
+	return 0;
+}
+
+void __mlibc_do_finalize() {
+	ExitQueue &eq = getExitQueue();
+	for(size_t i = eq.size(); i > 0; i--) {
+		auto handler = &eq[i - 1];
+		handler->function(handler->argument);
+	}
+}
+