libsanitizer/sanitizer_common/sanitizer_win_weak_interception.cpp

   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
  22 extern "C" {
  23 void *WINAPI GetModuleHandleA(const char *module_name);
  24 void abort();
  25 }
  26
  27 namespace __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.
  30 int 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.
  40 extern "C" {
  41 void __sanitizer_on_print(const char *str);
  42 void __sanitizer_weak_hook_memcmp(uptr called_pc, const void *s1,
  43                                   const void *s2, uptr n, int result);
  44 void __sanitizer_weak_hook_strcmp(uptr called_pc, const char *s1,
  45                                   const char *s2, int result);
  46 void __sanitizer_weak_hook_strncmp(uptr called_pc, const char *s1,
  47                                    const char *s2, uptr n, int result);
  48 void __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
  60 typedef void (*InterceptCB)();
  61 extern "C" {
  62 __declspec(allocate(".WEAK$A")) InterceptCB __start_weak_list;
  63 __declspec(allocate(".WEAK$Z")) InterceptCB __stop_weak_list;
  64 }
  65
  66 static 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
  85 static 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