android_system_core/base/liblog_symbols.cpp
Jiyong Park 5280b5c03e libbase uses liblog symbols via dlsym when it is built for APEX
libbase is a popular library that is used by many APEXes either directly
or transitively. It is being used by several Mainline modules that were
launched with Q, in which case everything in the APEX - including
libbase - shouldn't use new APIs that are added post Q, i.e. R.

libbase however is using a few new R symbols from liblog, and this is
preventing those Q-launching Mainline modules that are built in R source
tree from being installed to Q devices.

Fortunately, the dependencies to the new R symbols are guarded with a
flag; when the existence of the symbols are not guaranteed, it uses
dlsym. This change fixes the aforementioned problem by turning on the
flag also when libbase is built for an APEX.

Bug: 149569129
Test: TARGET_BUILD_APPS=com.android.media
vendor/google/build/build_mainline_modules.sh
adb install --staged out/dist/mainline_modules_arm64/com.android.media.apex
adb reboot
The APEX is installed and mediaextractor process doesn't crash

Change-Id: I44b5ec028850613cb45fc3e792f43cd8e87cfd00
2020-03-10 10:08:26 +09:00

91 lines
3.1 KiB
C++

/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "liblog_symbols.h"
#if defined(__ANDROID__)
#if !defined(NO_LIBLOG_DLSYM) || defined(__ANDROID_APEX__)
#define USE_DLSYM
#endif
#endif
#ifdef USE_DLSYM
#include <dlfcn.h>
#endif
namespace android {
namespace base {
#ifdef USE_DLSYM
const std::optional<LibLogFunctions>& GetLibLogFunctions() {
static std::optional<LibLogFunctions> liblog_functions = []() -> std::optional<LibLogFunctions> {
void* liblog_handle = dlopen("liblog.so", RTLD_NOW);
if (liblog_handle == nullptr) {
return {};
}
LibLogFunctions real_liblog_functions = {};
#define DLSYM(name) \
real_liblog_functions.name = \
reinterpret_cast<decltype(LibLogFunctions::name)>(dlsym(liblog_handle, #name)); \
if (real_liblog_functions.name == nullptr) { \
return {}; \
}
DLSYM(__android_log_set_logger)
DLSYM(__android_log_write_logger_data)
DLSYM(__android_log_logd_logger)
DLSYM(__android_log_stderr_logger)
DLSYM(__android_log_set_aborter)
DLSYM(__android_log_call_aborter)
DLSYM(__android_log_default_aborter)
DLSYM(__android_log_set_minimum_priority);
DLSYM(__android_log_get_minimum_priority);
DLSYM(__android_log_set_default_tag);
#undef DLSYM
return real_liblog_functions;
}();
return liblog_functions;
}
#else
const std::optional<LibLogFunctions>& GetLibLogFunctions() {
static std::optional<LibLogFunctions> liblog_functions = []() -> std::optional<LibLogFunctions> {
return LibLogFunctions{
.__android_log_set_logger = __android_log_set_logger,
.__android_log_write_logger_data = __android_log_write_logger_data,
.__android_log_logd_logger = __android_log_logd_logger,
.__android_log_stderr_logger = __android_log_stderr_logger,
.__android_log_set_aborter = __android_log_set_aborter,
.__android_log_call_aborter = __android_log_call_aborter,
.__android_log_default_aborter = __android_log_default_aborter,
.__android_log_set_minimum_priority = __android_log_set_minimum_priority,
.__android_log_get_minimum_priority = __android_log_get_minimum_priority,
.__android_log_set_default_tag = __android_log_set_default_tag,
};
}();
return liblog_functions;
}
#endif
} // namespace base
} // namespace android