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/*
* Copyright (C) 2019 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.
*/
#define _GNU_SOURCE 1
#include <stdint.h>
#include <string.h>
#include <string>
#if defined(__BIONIC__)
#include <gtest/gtest.h>
#include <unwindstack/DwarfSection.h>
#include <unwindstack/Elf.h>
#include <unwindstack/ElfInterface.h>
#include <unwindstack/Regs.h>
#include <unwindstack/RegsGetLocal.h>
#include <unwindstack/Unwinder.h>
// This test is specific to bionic to verify that __libc_init is
// properly setting the return address to undefined so that the
// unwind properly terminates.
namespace unwindstack {
static std::string DumpFrames(const UnwinderFromPid& unwinder) {
// Init this way so that the first frame of the backtrace starts on a new line.
std::string unwind("\n");
for (size_t i = 0; i < unwinder.NumFrames(); i++) {
unwind += unwinder.FormatFrame(i) + '\n';
}
return unwind;
}
static DwarfLocationEnum GetReturnAddressLocation(uint64_t rel_pc, DwarfSection* section) {
if (section == nullptr) {
return DWARF_LOCATION_INVALID;
}
const DwarfFde* fde = section->GetFdeFromPc(rel_pc);
if (fde == nullptr || fde->cie == nullptr) {
return DWARF_LOCATION_INVALID;
}
DwarfLocations regs;
if (!section->GetCfaLocationInfo(rel_pc, fde, ®s, ARCH_UNKNOWN)) {
return DWARF_LOCATION_INVALID;
}
auto reg_entry = regs.find(fde->cie->return_address_register);
if (reg_entry == regs.end()) {
return DWARF_LOCATION_INVALID;
}
return reg_entry->second.type;
}
static void VerifyReturnAddress(const FrameData& frame) {
// Now go and find information about the register data and verify that the relative pc results in
// an undefined register.
auto file_memory = Memory::CreateFileMemory(frame.map_info->name(), 0);
Elf elf(file_memory);
ASSERT_TRUE(frame.map_info != nullptr);
ASSERT_TRUE(elf.Init()) << "Failed to init elf object from " << frame.map_info->name().c_str();
ASSERT_TRUE(elf.valid()) << "Elf " << frame.map_info->name().c_str() << " is not valid.";
ElfInterface* interface = elf.interface();
// Only check the eh_frame and the debug_frame since the undefined register
// is set using a cfi directive.
// Check debug_frame first, then eh_frame since debug_frame always
// contains the most specific data.
DwarfLocationEnum location = GetReturnAddressLocation(frame.rel_pc, interface->debug_frame());
if (location == DWARF_LOCATION_UNDEFINED) {
return;
}
location = GetReturnAddressLocation(frame.rel_pc, interface->eh_frame());
ASSERT_EQ(DWARF_LOCATION_UNDEFINED, location);
}
// This test assumes that it starts from the main thread, and that the
// libc.so on device will include symbols so that function names can
// be resolved.
TEST(VerifyBionicTermination, local_terminate) {
std::unique_ptr<Regs> regs(Regs::CreateFromLocal());
UnwinderFromPid unwinder(512, getpid());
unwinder.SetRegs(regs.get());
RegsGetLocal(regs.get());
unwinder.Unwind();
ASSERT_LT(0U, unwinder.NumFrames());
SCOPED_TRACE(DumpFrames(unwinder));
// Look for the frame that includes __libc_init, there should only
// be one and it should be the last.
bool found = false;
const std::vector<FrameData>& frames = unwinder.frames();
for (size_t i = 0; i < unwinder.NumFrames(); i++) {
const FrameData& frame = frames[i];
if (frame.function_name == "__libc_init" && frame.map_info != nullptr &&
!frame.map_info->name().empty() &&
std::string("libc.so") == basename(frame.map_info->name().c_str())) {
ASSERT_EQ(unwinder.NumFrames(), i + 1) << "__libc_init is not last frame.";
ASSERT_NO_FATAL_FAILURE(VerifyReturnAddress(frame));
found = true;
}
}
ASSERT_TRUE(found) << "Unable to find libc.so:__libc_init frame\n";
}
} // namespace unwindstack
#endif
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