libsanitizer/sanitizer_common/sanitizer_win_weak_interception.cc

   1 //===-- sanitizer_win_weak_interception.cc --------------------------------===//
   2 //
   3 // This file is distributed under the University of Illinois Open Source
   4 // License. See LICENSE.TXT for details.
   5 //
   6 //===----------------------------------------------------------------------===//
   7 // This module should be included in the sanitizer when it is implemented as a
   8 // shared library on Windows (dll), in order to delegate the calls of weak
   9 // functions to the implementation in the main executable when a strong
  10 // definition is provided.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "sanitizer_common/sanitizer_platform.h"
  14 #if SANITIZER_WINDOWS && SANITIZER_DYNAMIC
  15 #include "sanitizer_win_weak_interception.h"
  16 #include "sanitizer_allocator_interface.h"
  17 #include "sanitizer_interface_internal.h"
  18 #include "sanitizer_win_defs.h"
  19 #include "interception/interception.h"
  20
  21 extern "C" {
  22 void *WINAPI GetModuleHandleA(const char *module_name);
  23 void abort();
  24 }
  25
  26 namespace __sanitizer {
  27 // Try to get a pointer to real_function in the main module and override
  28 // dll_function with that pointer. If the function isn't found, nothing changes.
  29 int interceptWhenPossible(uptr dll_function, const char *real_function) {
  30   uptr real = __interception::InternalGetProcAddress(
  31       (void *)GetModuleHandleA(0), real_function);
  32   if (real && !__interception::OverrideFunction((uptr)dll_function, real, 0))
  33     abort();
  34   return 0;
  35 }
  36 } // namespace __sanitizer
  37
  38 // Declare weak hooks.
  39 extern "C" {
  40 void __sanitizer_weak_hook_memcmp(uptr called_pc, const void *s1,
  41                                   const void *s2, uptr n, int result);
  42 void __sanitizer_weak_hook_strcmp(uptr called_pc, const char *s1,
  43                                   const char *s2, int result);
  44 void __sanitizer_weak_hook_strncmp(uptr called_pc, const char *s1,
  45                                    const char *s2, uptr n, int result);
  46 void __sanitizer_weak_hook_strstr(uptr called_pc, const char *s1,
  47                                   const char *s2, char *result);
  48 }
  49
  50 // Include Sanitizer Common interface.
  51 #define INTERFACE_FUNCTION(Name)
  52 #define INTERFACE_WEAK_FUNCTION(Name) INTERCEPT_SANITIZER_WEAK_FUNCTION(Name)
  53 #include "sanitizer_common_interface.inc"
  54
  55 #pragma section(".WEAK$A", read)  // NOLINT
  56 #pragma section(".WEAK$Z", read)  // NOLINT
  57
  58 typedef void (*InterceptCB)();
  59 extern "C" {
  60 __declspec(allocate(".WEAK$A")) InterceptCB __start_weak_list;
  61 __declspec(allocate(".WEAK$Z")) InterceptCB __stop_weak_list;
  62 }
  63
  64 static int weak_intercept_init() {
  65   static bool flag = false;
  66   // weak_interception_init is expected to be called by only one thread.
  67   if (flag) return 0;
  68   flag = true;
  69
  70   for (InterceptCB *it = &__start_weak_list; it < &__stop_weak_list; ++it)
  71     if (*it)
  72       (*it)();
  73
  74   // In DLLs, the callbacks are expected to return 0,
  75   // otherwise CRT initialization fails.
  76   return 0;
  77 }
  78
  79 #pragma section(".CRT$XIB", long, read)  // NOLINT
  80 __declspec(allocate(".CRT$XIB")) int (*__weak_intercept_preinit)() =
  81     weak_intercept_init;
  82
  83 static void WINAPI weak_intercept_thread_init(void *mod, unsigned long reason,
  84                                               void *reserved) {
  85   if (reason == /*DLL_PROCESS_ATTACH=*/1) weak_intercept_init();
  86 }
  87
  88 #pragma section(".CRT$XLAB", long, read)  // NOLINT
  89 __declspec(allocate(".CRT$XLAB")) void(WINAPI *__weak_intercept_tls_init)(
  90     void *, unsigned long, void *) = weak_intercept_thread_init;
  91
  92 #endif // SANITIZER_WINDOWS && SANITIZER_DYNAMIC