diff options
Diffstat (limited to 'base')
-rw-r--r-- | base/base.gyp | 1 | ||||
-rw-r--r-- | base/win/dllmain.cc | 125 |
2 files changed, 0 insertions, 126 deletions
diff --git a/base/base.gyp b/base/base.gyp index b37ddb0..efc0333 100644 --- a/base/base.gyp +++ b/base/base.gyp @@ -121,7 +121,6 @@ 'at_exit_unittest.cc', 'atomicops_unittest.cc', 'base64_unittest.cc', - 'win/dllmain.cc', 'bind_unittest.cc', 'bind_unittest.nc', 'bits_unittest.cc', diff --git a/base/win/dllmain.cc b/base/win/dllmain.cc deleted file mode 100644 index 8e0ce4b..0000000 --- a/base/win/dllmain.cc +++ /dev/null @@ -1,125 +0,0 @@ -// Copyright (c) 2011 The Chromium Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. - -// Windows doesn't support pthread_key_create's destr_function, and in fact -// it's a bit tricky to get code to run when a thread exits. This is -// cargo-cult magic from http://www.codeproject.com/threads/tls.asp. -// We are trying to be compatible with both a LoadLibrary style invocation, as -// well as static linking. This code only needs to be included if we use -// LoadLibrary, but it hooks into the "standard" set of TLS callbacks that are -// provided for static linking. - -// This code is deliberately written to match the style of calls seen in -// base/threading/thread_local_storage_win.cc. Please keep the two in sync if -// coding conventions are changed. - -// WARNING: Do *NOT* try to include this in the construction of the base -// library, even though it potentially drives code in -// base/threading/thread_local_storage_win.cc. If you do, some users will end -// up getting duplicate definition of DllMain() in some of their later links. - -// Force a reference to _tls_used to make the linker create the TLS directory -// if it's not already there (that is, even if __declspec(thread) is not used). -// To make sure we really traverse the whole list, we put down two elements, and -// then check that we called both functions when we scanned the list. -// Force a reference to p_thread_callback_dllmain_first_entry and -// p_thread_callback_dllmain_first_entry to prevent whole program optimization -// from discarding the variables. - -#include <windows.h> - -#include "base/logging.h" - -// Indicate if another service is scanning the callbacks. When this becomes -// set to true, then DllMain() will stop supporting the callback service. This -// value is set to true the first time any of our callbacks are called, as that -// shows that some other service is handling callbacks. -static bool linker_notifications_are_active = false; - -// This will be our mostly no-op callback that we'll list (twice). We won't -// deliberately call it, and if it is called, that means we don't need to do any -// of the callbacks anymore. We expect such a call to arrive via a -// THREAD_ATTACH message, long before we'd have to perform our THREAD_DETACH -// callbacks. -static void NTAPI on_callback(PVOID h, DWORD reason, PVOID reserved); - -#ifdef _WIN64 - -#pragma comment(linker, "/INCLUDE:_tls_used") -#pragma comment(linker, "/INCLUDE:p_thread_callback_dllmain_first_entry") -#pragma comment(linker, "/INCLUDE:p_thread_callback_dllmain_later_entry") - -#else // _WIN64 - -#pragma comment(linker, "/INCLUDE:__tls_used") -#pragma comment(linker, "/INCLUDE:_p_thread_callback_dllmain_first_entry") -#pragma comment(linker, "/INCLUDE:_p_thread_callback_dllmain_later_entry") - -#endif // _WIN64 - -// extern "C" suppresses C++ name mangling so we know the symbol names for the -// linker /INCLUDE:symbol pragmas above. -extern "C" { -#ifdef _WIN64 - -// .CRT section is merged with .rdata on x64 so it must be constant data. -#pragma data_seg(push, old_seg) -// Use earliest possible name in the .CRT$XL? list of segments. -#pragma const_seg(".CRT$XLA") -// When defining a const variable, it must have external linkage to be sure the -// linker doesn't discard it. -extern const PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_first_entry; -const PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_first_entry = on_callback; -// The latest possible name in the .CRT$XL? (other than *Z, which has a NULL). -#pragma const_seg(".CRT$XLY") -extern const PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_later_entry; -const PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_later_entry = on_callback; -#pragma data_seg(pop, old_seg) - -#else // _WIN64 - -#pragma data_seg(push, old_seg) -// Use earliest possible name in the .CRT$XL? list of segments. -#pragma data_seg(".CRT$XLA") -PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_first_entry = on_callback; -// The latest possible name in the .CRT$XL? (other than *Z, which has a NULL). -#pragma data_seg(".CRT$XLY") -PIMAGE_TLS_CALLBACK p_thread_callback_dllmain_later_entry = on_callback; -#pragma data_seg(pop, old_seg) - -#endif // _WIN64 -} // extern "C" - - -// Make DllMain call the listed callbacks. This way any third parties that are -// linked in will also be called. -BOOL WINAPI DllMain(PVOID h, DWORD reason, PVOID reserved) { - if (DLL_THREAD_DETACH != reason && DLL_PROCESS_DETACH != reason) - return true; // We won't service THREAD_ATTACH calls. - - if (linker_notifications_are_active) - return true; // Some other service is doing this work. - - // Use our first entry as a starting point, but don't call it. - PIMAGE_TLS_CALLBACK* it = &p_thread_callback_dllmain_first_entry; - while (*++it != NULL || it < &p_thread_callback_dllmain_later_entry) { - if (*it == NULL || *it == on_callback) - continue; // Don't bother to call our own callback. - (*it)(h, reason, reserved); - } - return true; -} - -static void NTAPI on_callback(PVOID h, DWORD reason, PVOID reserved) { - // Do nothing. We were just a place holder in the list used to test that we - // call all items. - // If we are called, it means that some other system is scanning the callbacks - // and we don't need to do so in DllMain(). - linker_notifications_are_active = true; - // Note: If some other routine some how plays this same game... we could both - // decide not to do the scanning <sigh>, but this trick should suppress - // duplicate calls on Vista, where the runtime takes care of the callbacks, - // and allow us to do the callbacks on XP, where we are currently devoid of - // callbacks (due to an explicit LoadLibrary call). -} |