1//===-- sanitizer_win_dll_thunk.cpp ---------------------------------------===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8// This file defines a family of thunks that should be statically linked into 9// the DLLs that have instrumentation in order to delegate the calls to the 10// shared runtime that lives in the main binary. 11// See https://github.com/google/sanitizers/issues/209 for the details. 12//===----------------------------------------------------------------------===// 13 14#ifdef SANITIZER_DLL_THUNK 15#include "sanitizer_win_defs.h" 16#include "sanitizer_win_dll_thunk.h" 17#include "interception/interception.h" 18 19extern "C" { 20void *WINAPI GetModuleHandleA(const char *module_name); 21void abort(); 22} 23 24namespace __sanitizer { 25uptr dllThunkGetRealAddrOrDie(const char *name) { 26 uptr ret = 27 __interception::InternalGetProcAddress((void *)GetModuleHandleA(0), name); 28 if (!ret) 29 abort(); 30 return ret; 31} 32 33int dllThunkIntercept(const char* main_function, uptr dll_function) { 34 uptr wrapper = dllThunkGetRealAddrOrDie(main_function); 35 if (!__interception::OverrideFunction(dll_function, wrapper, 0)) 36 abort(); 37 return 0; 38} 39 40int dllThunkInterceptWhenPossible(const char* main_function, 41 const char* default_function, uptr dll_function) { 42 uptr wrapper = __interception::InternalGetProcAddress( 43 (void *)GetModuleHandleA(0), main_function); 44 if (!wrapper) 45 wrapper = dllThunkGetRealAddrOrDie(default_function); 46 if (!__interception::OverrideFunction(dll_function, wrapper, 0)) 47 abort(); 48 return 0; 49} 50} // namespace __sanitizer 51 52// Include Sanitizer Common interface. 53#define INTERFACE_FUNCTION(Name) INTERCEPT_SANITIZER_FUNCTION(Name) 54#define INTERFACE_WEAK_FUNCTION(Name) INTERCEPT_SANITIZER_WEAK_FUNCTION(Name) 55#include "sanitizer_common_interface.inc" 56 57#pragma section(".DLLTH$A", read) 58#pragma section(".DLLTH$Z", read) 59 60typedef void (*DllThunkCB)(); 61extern "C" { 62__declspec(allocate(".DLLTH$A")) DllThunkCB __start_dll_thunk; 63__declspec(allocate(".DLLTH$Z")) DllThunkCB __stop_dll_thunk; 64} 65 66// Disable compiler warnings that show up if we declare our own version 67// of a compiler intrinsic (e.g. strlen). 68#pragma warning(disable: 4391) 69#pragma warning(disable: 4392) 70 71extern "C" int __dll_thunk_init() { 72 static bool flag = false; 73 // __dll_thunk_init is expected to be called by only one thread. 74 if (flag) return 0; 75 flag = true; 76 77 for (DllThunkCB *it = &__start_dll_thunk; it < &__stop_dll_thunk; ++it) 78 if (*it) 79 (*it)(); 80 81 // In DLLs, the callbacks are expected to return 0, 82 // otherwise CRT initialization fails. 83 return 0; 84} 85 86// We want to call dll_thunk_init before C/C++ initializers / constructors are 87// executed, otherwise functions like memset might be invoked. 88#pragma section(".CRT$XIB", long, read) 89__declspec(allocate(".CRT$XIB")) int (*__dll_thunk_preinit)() = 90 __dll_thunk_init; 91 92static void WINAPI dll_thunk_thread_init(void *mod, unsigned long reason, 93 void *reserved) { 94 if (reason == /*DLL_PROCESS_ATTACH=*/1) __dll_thunk_init(); 95} 96 97#pragma section(".CRT$XLAB", long, read) 98__declspec(allocate(".CRT$XLAB")) void (WINAPI *__dll_thunk_tls_init)(void *, 99 unsigned long, void *) = dll_thunk_thread_init; 100 101#endif // SANITIZER_DLL_THUNK 102