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