1//===-- sanitizer_win_weak_interception.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 module should be included in the sanitizer when it is implemented as a
9// shared library on Windows (dll), in order to delegate the calls of weak
10// functions to the implementation in the main executable when a strong
11// definition is provided.
12//===----------------------------------------------------------------------===//
13
14#include "sanitizer_platform.h"
15#if SANITIZER_WINDOWS && SANITIZER_DYNAMIC
16#include "sanitizer_win_weak_interception.h"
17#include "sanitizer_allocator_interface.h"
18#include "sanitizer_interface_internal.h"
19#include "sanitizer_win_defs.h"
20#include "interception/interception.h"
21
22extern "C" {
23void *WINAPI GetModuleHandleA(const char *module_name);
24void abort();
25}
26
27namespace __sanitizer {
28// Try to get a pointer to real_function in the main module and override
29// dll_function with that pointer. If the function isn't found, nothing changes.
30int interceptWhenPossible(uptr dll_function, const char *real_function) {
31 uptr real = __interception::InternalGetProcAddress(
32 (void *)GetModuleHandleA(0), real_function);
33 if (real && !__interception::OverrideFunction((uptr)dll_function, real, 0))
34 abort();
35 return 0;
36}
37} // namespace __sanitizer
38
39// Declare weak hooks.
40extern "C" {
41void __sanitizer_on_print(const char *str);
42void __sanitizer_weak_hook_memcmp(uptr called_pc, const void *s1,
43 const void *s2, uptr n, int result);
44void __sanitizer_weak_hook_strcmp(uptr called_pc, const char *s1,
45 const char *s2, int result);
46void __sanitizer_weak_hook_strncmp(uptr called_pc, const char *s1,
47 const char *s2, uptr n, int result);
48void __sanitizer_weak_hook_strstr(uptr called_pc, const char *s1,
49 const char *s2, char *result);
50}
51
52// Include Sanitizer Common interface.
53#define INTERFACE_FUNCTION(Name)
54#define INTERFACE_WEAK_FUNCTION(Name) INTERCEPT_SANITIZER_WEAK_FUNCTION(Name)
55#include "sanitizer_common_interface.inc"
56
57#pragma section(".WEAK$A", read)
58#pragma section(".WEAK$Z", read)
59
60typedef void (*InterceptCB)();
61extern "C" {
62__declspec(allocate(".WEAK$A")) InterceptCB __start_weak_list;
63__declspec(allocate(".WEAK$Z")) InterceptCB __stop_weak_list;
64}
65
66static int weak_intercept_init() {
67 static bool flag = false;
68 // weak_interception_init is expected to be called by only one thread.
69 if (flag) return 0;
70 flag = true;
71
72 for (InterceptCB *it = &__start_weak_list; it < &__stop_weak_list; ++it)
73 if (*it)
74 (*it)();
75
76 // In DLLs, the callbacks are expected to return 0,
77 // otherwise CRT initialization fails.
78 return 0;
79}
80
81#pragma section(".CRT$XIB", long, read)
82__declspec(allocate(".CRT$XIB")) int (*__weak_intercept_preinit)() =
83 weak_intercept_init;
84
85static void WINAPI weak_intercept_thread_init(void *mod, unsigned long reason,
86 void *reserved) {
87 if (reason == /*DLL_PROCESS_ATTACH=*/1) weak_intercept_init();
88}
89
90#pragma section(".CRT$XLAB", long, read)
91__declspec(allocate(".CRT$XLAB")) void(WINAPI *__weak_intercept_tls_init)(
92 void *, unsigned long, void *) = weak_intercept_thread_init;
93
94#endif // SANITIZER_WINDOWS && SANITIZER_DYNAMIC
95

source code of compiler-rt/lib/sanitizer_common/sanitizer_win_weak_interception.cpp