1 files changed, 254 insertions, 0 deletions
diff --git a/third_party/rlbox/include/rlbox_noop_sandbox.hpp b/third_party/rlbox/include/rlbox_noop_sandbox.hpp
new file mode 100644
index 0000000000..d1e48edb4f
--- /dev/null
+++ b/third_party/rlbox/include/rlbox_noop_sandbox.hpp
@@ -0,0 +1,254 @@
+#pragma once
+
+#include <cstdint>
+#include <cstdlib>
+#include <mutex>
+#ifndef RLBOX_USE_CUSTOM_SHARED_LOCK
+#  include <shared_mutex>
+#endif
+#include <utility>
+
+#include "rlbox_helpers.hpp"
+
+namespace rlbox {
+
+class rlbox_noop_sandbox;
+
+struct rlbox_noop_sandbox_thread_data
+{
+  rlbox_noop_sandbox* sandbox;
+  uint32_t last_callback_invoked;
+};
+
+#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
+
+rlbox_noop_sandbox_thread_data* get_rlbox_noop_sandbox_thread_data();
+#  define RLBOX_NOOP_SANDBOX_STATIC_VARIABLES()                                \
+    thread_local rlbox::rlbox_noop_sandbox_thread_data                         \
+      rlbox_noop_sandbox_thread_info{ 0, 0 };                                  \
+    namespace rlbox {                                                          \
+      rlbox_noop_sandbox_thread_data* get_rlbox_noop_sandbox_thread_data()     \
+      {                                                                        \
+        return &rlbox_noop_sandbox_thread_info;                                \
+      }                                                                        \
+    }                                                                          \
+    static_assert(true, "Enforce semi-colon")
+
+#endif
+
+/**
+ * @brief Class that implements the null sandbox. This sandbox doesn't actually
+ * provide any isolation and only serves as a stepping stone towards migrating
+ * an application to use the RLBox API.
+ */
+class rlbox_noop_sandbox
+{
+public:
+  // Stick with the system defaults
+  using T_LongLongType = long long;
+  using T_LongType = long;
+  using T_IntType = int;
+  using T_PointerType = void*;
+  using T_ShortType = short;
+  // no-op sandbox can transfer buffers as there is no sandboxings
+  // Thus transfer is a noop
+  using can_grant_deny_access = void;
+
+private:
+  RLBOX_SHARED_LOCK(callback_mutex);
+  static inline const uint32_t MAX_CALLBACKS = 64;
+  void* callback_unique_keys[MAX_CALLBACKS]{ 0 };
+  void* callbacks[MAX_CALLBACKS]{ 0 };
+
+#ifndef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
+  thread_local static inline rlbox_noop_sandbox_thread_data thread_data{ 0, 0 };
+#endif
+
+  template<uint32_t N, typename T_Ret, typename... T_Args>
+  static T_Ret callback_trampoline(T_Args... params)
+  {
+#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
+    auto& thread_data = *get_rlbox_noop_sandbox_thread_data();
+#endif
+    thread_data.last_callback_invoked = N;
+    using T_Func = T_Ret (*)(T_Args...);
+    T_Func func;
+    {
+#ifndef RLBOX_SINGLE_THREADED_INVOCATIONS
+      RLBOX_ACQUIRE_SHARED_GUARD(lock, thread_data.sandbox->callback_mutex);
+#endif
+      func = reinterpret_cast<T_Func>(thread_data.sandbox->callbacks[N]);
+    }
+    // Callbacks are invoked through function pointers, cannot use std::forward
+    // as we don't have caller context for T_Args, which means they are all
+    // effectively passed by value
+    return func(params...);
+  }
+
+protected:
+  inline void impl_create_sandbox() {}
+
+  inline void impl_destroy_sandbox() {}
+
+  template<typename T>
+  inline void* impl_get_unsandboxed_pointer(T_PointerType p) const
+  {
+    return p;
+  }
+
+  template<typename T>
+  inline T_PointerType impl_get_sandboxed_pointer(const void* p) const
+  {
+    return const_cast<T_PointerType>(p);
+  }
+
+  template<typename T>
+  static inline void* impl_get_unsandboxed_pointer_no_ctx(
+    T_PointerType p,
+    const void* /* example_unsandboxed_ptr */,
+    rlbox_noop_sandbox* (* // Func ptr
+                         /* param: expensive_sandbox_finder */)(
+      const void* example_unsandboxed_ptr))
+  {
+    return p;
+  }
+
+  template<typename T>
+  static inline T_PointerType impl_get_sandboxed_pointer_no_ctx(
+    const void* p,
+    const void* /* example_unsandboxed_ptr */,
+    rlbox_noop_sandbox* (* // Func ptr
+                         /* param: expensive_sandbox_finder */)(
+      const void* example_unsandboxed_ptr))
+  {
+    return const_cast<T_PointerType>(p);
+  }
+
+  inline T_PointerType impl_malloc_in_sandbox(size_t size)
+  {
+    void* p = malloc(size);
+    return p;
+  }
+
+  inline void impl_free_in_sandbox(T_PointerType p) { free(p); }
+
+  static inline bool impl_is_in_same_sandbox(const void*, const void*)
+  {
+    return true;
+  }
+
+  inline bool impl_is_pointer_in_sandbox_memory(const void*) { return true; }
+  inline bool impl_is_pointer_in_app_memory(const void*) { return true; }
+
+  inline size_t impl_get_total_memory()
+  {
+    return std::numeric_limits<size_t>::max();
+  }
+
+  inline void* impl_get_memory_location()
+  {
+    // There isn't any sandbox memory for the noop_sandbox as we just redirect
+    // to the app. Also, this is mostly used for pointer swizzling or sandbox
+    // bounds checks which is also not present/not required. So we can just
+    // return null
+    return nullptr;
+  }
+
+  // adding a template so that we can use static_assert to fire only if this
+  // function is invoked
+  template<typename T = void>
+  void* impl_lookup_symbol(const char* /* func_name */)
+  {
+    // Will fire if this impl_lookup_symbol is ever called for the static
+    // sandbox
+    constexpr bool fail = std::is_same_v<T, void>;
+    rlbox_detail_static_fail_because(
+      fail,
+      "The no_op_sandbox uses static calls and thus developers should add\n\n"
+      "#define RLBOX_USE_STATIC_CALLS() rlbox_noop_sandbox_lookup_symbol\n\n"
+      "to their code, to ensure that static calls are handled correctly.");
+
+    return nullptr;
+  }
+
+#define rlbox_noop_sandbox_lookup_symbol(func_name)                            \
+  reinterpret_cast<void*>(&func_name) /* NOLINT */
+
+  template<typename T, typename T_Converted, typename... T_Args>
+  auto impl_invoke_with_func_ptr(T_Converted* func_ptr, T_Args&&... params)
+  {
+#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
+    auto& thread_data = *get_rlbox_noop_sandbox_thread_data();
+#endif
+    auto old_sandbox = thread_data.sandbox;
+    thread_data.sandbox = this;
+    auto on_exit = detail::make_scope_exit([&] {
+      thread_data.sandbox = old_sandbox;
+    });
+    return (*func_ptr)(params...);
+  }
+
+  template<typename T_Ret, typename... T_Args>
+  inline T_PointerType impl_register_callback(void* key, void* callback)
+  {
+    RLBOX_ACQUIRE_UNIQUE_GUARD(lock, callback_mutex);
+
+    void* chosen_trampoline = nullptr;
+
+    // need a compile time for loop as we we need I to be a compile time value
+    // this is because we are returning the I'th callback trampoline
+    detail::compile_time_for<MAX_CALLBACKS>([&](auto I) {
+      if (!chosen_trampoline && callback_unique_keys[I.value] == nullptr) {
+        callback_unique_keys[I.value] = key;
+        callbacks[I.value] = callback;
+        chosen_trampoline = reinterpret_cast<void*>(
+          callback_trampoline<I.value, T_Ret, T_Args...>);
+      }
+    });
+
+    return reinterpret_cast<T_PointerType>(chosen_trampoline);
+  }
+
+  static inline std::pair<rlbox_noop_sandbox*, void*>
+  impl_get_executed_callback_sandbox_and_key()
+  {
+#ifdef RLBOX_EMBEDDER_PROVIDES_TLS_STATIC_VARIABLES
+    auto& thread_data = *get_rlbox_noop_sandbox_thread_data();
+#endif
+    auto sandbox = thread_data.sandbox;
+    auto callback_num = thread_data.last_callback_invoked;
+    void* key = sandbox->callback_unique_keys[callback_num];
+    return std::make_pair(sandbox, key);
+  }
+
+  template<typename T_Ret, typename... T_Args>
+  inline void impl_unregister_callback(void* key)
+  {
+    RLBOX_ACQUIRE_UNIQUE_GUARD(lock, callback_mutex);
+    for (uint32_t i = 0; i < MAX_CALLBACKS; i++) {
+      if (callback_unique_keys[i] == key) {
+        callback_unique_keys[i] = nullptr;
+        callbacks[i] = nullptr;
+        break;
+      }
+    }
+  }
+
+  template<typename T>
+  inline T* impl_grant_access(T* src, size_t num, bool& success)
+  {
+    RLBOX_UNUSED(num);
+    success = true;
+    return src;
+  }
+
+  template<typename T>
+  inline T* impl_deny_access(T* src, size_t num, bool& success)
+  {
+    RLBOX_UNUSED(num);
+    success = true;
+    return src;
+  }
+};
+
+}