blob: b14bbf76d9a765bb88702743e7f659709d4f81a1 [file] [log] [blame]
//===-- sanitizer_win_weak_interception.cpp -------------------------------===//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
// This module should be included in the sanitizer when it is implemented as a
// shared library on Windows (dll), in order to delegate the calls of weak
// functions to the implementation in the main executable when a strong
// definition is provided.
#include "sanitizer_platform.h"
#include "sanitizer_win_weak_interception.h"
#include "sanitizer_allocator_interface.h"
#include "sanitizer_interface_internal.h"
#include "sanitizer_win_defs.h"
#include "interception/interception.h"
extern "C" {
void *WINAPI GetModuleHandleA(const char *module_name);
void abort();
namespace __sanitizer {
// Try to get a pointer to real_function in the main module and override
// dll_function with that pointer. If the function isn't found, nothing changes.
int interceptWhenPossible(uptr dll_function, const char *real_function) {
uptr real = __interception::InternalGetProcAddress(
(void *)GetModuleHandleA(0), real_function);
if (real && !__interception::OverrideFunction((uptr)dll_function, real, 0))
return 0;
} // namespace __sanitizer
// Declare weak hooks.
extern "C" {
void __sanitizer_on_print(const char *str);
void __sanitizer_weak_hook_memcmp(uptr called_pc, const void *s1,
const void *s2, uptr n, int result);
void __sanitizer_weak_hook_strcmp(uptr called_pc, const char *s1,
const char *s2, int result);
void __sanitizer_weak_hook_strncmp(uptr called_pc, const char *s1,
const char *s2, uptr n, int result);
void __sanitizer_weak_hook_strstr(uptr called_pc, const char *s1,
const char *s2, char *result);
// Include Sanitizer Common interface.
#include ""
#pragma section(".WEAK$A", read)
#pragma section(".WEAK$Z", read)
typedef void (*InterceptCB)();
extern "C" {
__declspec(allocate(".WEAK$A")) InterceptCB __start_weak_list;
__declspec(allocate(".WEAK$Z")) InterceptCB __stop_weak_list;
static int weak_intercept_init() {
static bool flag = false;
// weak_interception_init is expected to be called by only one thread.
if (flag) return 0;
flag = true;
for (InterceptCB *it = &__start_weak_list; it < &__stop_weak_list; ++it)
if (*it)
// In DLLs, the callbacks are expected to return 0,
// otherwise CRT initialization fails.
return 0;
#pragma section(".CRT$XIB", long, read)
__declspec(allocate(".CRT$XIB")) int (*__weak_intercept_preinit)() =
static void WINAPI weak_intercept_thread_init(void *mod, unsigned long reason,
void *reserved) {
if (reason == /*DLL_PROCESS_ATTACH=*/1) weak_intercept_init();
#pragma section(".CRT$XLAB", long, read)
__declspec(allocate(".CRT$XLAB")) void(WINAPI *__weak_intercept_tls_init)(
void *, unsigned long, void *) = weak_intercept_thread_init;