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#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;
}
};
}