/*
|
* Copyright (C) 2017 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 <dlfcn.h>
|
#include <stdint.h>
|
#include <stdio.h>
|
#include <stdlib.h>
|
|
static uintptr_t g_flag = 0;
|
|
static void __attribute__((constructor)) init_flag() {
|
g_flag = reinterpret_cast<uintptr_t>(dlsym(RTLD_DEFAULT, "dlsym"));
|
}
|
|
static const char* is_ctor_called() __attribute__ ((ifunc("is_ctor_called_ifun")));
|
|
extern "C" const char* foo() __attribute__ ((ifunc ("foo_ifunc")));
|
|
// Static linker creates GLOBAL/IFUNC symbol and JUMP_SLOT relocation type for plt segment
|
extern "C" const char* is_ctor_called_jump_slot() __attribute__ ((ifunc("is_ctor_called_ifun")));
|
|
extern "C" const char* is_ctor_called_irelative() {
|
// Call internal ifunc-resolved function with IRELATIVE reloc
|
return is_ctor_called();
|
}
|
|
extern "C" const char* var_true = "true";
|
extern "C" const char* var_false = "false";
|
|
extern "C" const char* v1 = "unset";
|
extern "C" const char* v2 = "set";
|
|
extern "C" void* is_ctor_called_ifun() {
|
return g_flag == 0 ? &var_false : &var_true;
|
}
|
|
extern "C" void* foo_ifunc() {
|
char* choice = getenv("IFUNC_CHOICE");
|
return choice == nullptr ? &v1 : &v2;
|
}
|
