1 files changed, 42 insertions, 0 deletions
diff --git a/libc/src/stdlib/exit_handler.cpp b/libc/src/stdlib/exit_handler.cpp
new file mode 100644
index 000000000000..ed41247e4a31
--- /dev/null
+++ b/libc/src/stdlib/exit_handler.cpp
@@ -0,0 +1,42 @@
+//===--- Implementation of exit_handler------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/stdlib/exit_handler.h"
+#include "src/__support/CPP/mutex.h" // lock_guard
+
+namespace LIBC_NAMESPACE {
+
+constinit ExitCallbackList at_quick_exit_callbacks;
+constinit ExitCallbackList atexit_callbacks;
+
+Mutex handler_list_mtx(false, false, false, false);
+
+void stdc_at_exit_func(void *payload) {
+  reinterpret_cast<StdCAtExitCallback *>(payload)();
+}
+
+void call_exit_callbacks(ExitCallbackList &callbacks) {
+  handler_list_mtx.lock();
+  while (!callbacks.empty()) {
+    AtExitUnit &unit = callbacks.back();
+    callbacks.pop_back();
+    handler_list_mtx.unlock();
+    unit.callback(unit.payload);
+    handler_list_mtx.lock();
+  }
+  ExitCallbackList::destroy(&callbacks);
+}
+
+int add_atexit_unit(ExitCallbackList &callbacks, const AtExitUnit &unit) {
+  cpp::lock_guard lock(handler_list_mtx);
+  if (callbacks.push_back(unit))
+    return 0;
+  return -1;
+}
+
+} // namespace LIBC_NAMESPACE