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android_system_core/libunwindstack/tests/ElfTest.cpp
Christopher Ferris 4cc36d2b43 Fix handling of load bias values. 
It turns out that for the dwarf information, if a FDE indicates it's pc
relative, then pc has to be incremented by the load bias. If not, then
it should not be incremented.

Previously, the code always subtracted load bias values from pcs, and assumed
that all fdes were incremented by load bias values. The new code actually
reads the fdes and adjusted the pcs in the fde and in the eh frame hdr so
that load bias values are already handled properly.

In addition, add dumping of arm exidx values in unwind_reg_info. This allowed
verifying that the debug frame in those elf files was being handled properly.

Added a new unit test that only has a debug frame that has a non-zero load
bias and has fde entries that do not have pc relative encoding.

Fix a couple of other small bugs.

Bug: 109824792

Test: All libbacktrace/libunwindstack unit tests pass.
Test: Ran ART 137-cfi test and 004-ThreadStress.
Test: Verify that displaying the fde start and end pc actually match the
Test: real data for fde that have pc relative set, and that don't.
Test: Verified that the unwind information for arm exidx matches the
Test: debug frame data.

Change-Id: I707555286b5cb05df9f25489e8c5ede753cfe0fb
2018-06-11 18:53:55 -07:00

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/*
* Copyright (C) 2016 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 <elf.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <gmock/gmock.h>
#include <gtest/gtest.h>
#include <unwindstack/Elf.h>
#include <unwindstack/MapInfo.h>
#include <unwindstack/RegsArm.h>
#include "ElfFake.h"
#include "ElfTestUtils.h"
#include "LogFake.h"
#include "MemoryFake.h"
#if !defined(PT_ARM_EXIDX)
#define PT_ARM_EXIDX 0x70000001
#endif
namespace unwindstack {
class ElfTest : public ::testing::Test {
protected:
void SetUp() override {
memory_ = new MemoryFake;
}
void InitElf32(uint32_t machine_type) {
Elf32_Ehdr ehdr;
TestInitEhdr<Elf32_Ehdr>(&ehdr, ELFCLASS32, machine_type);
ehdr.e_phoff = 0x100;
ehdr.e_ehsize = sizeof(ehdr);
ehdr.e_phentsize = sizeof(Elf32_Phdr);
ehdr.e_phnum = 1;
ehdr.e_shentsize = sizeof(Elf32_Shdr);
if (machine_type == EM_ARM) {
ehdr.e_flags = 0x5000200;
ehdr.e_phnum = 2;
}
memory_->SetMemory(0, &ehdr, sizeof(ehdr));
Elf32_Phdr phdr;
memset(&phdr, 0, sizeof(phdr));
phdr.p_type = PT_LOAD;
phdr.p_filesz = 0x10000;
phdr.p_memsz = 0x10000;
phdr.p_flags = PF_R | PF_X;
phdr.p_align = 0x1000;
memory_->SetMemory(0x100, &phdr, sizeof(phdr));
if (machine_type == EM_ARM) {
memset(&phdr, 0, sizeof(phdr));
phdr.p_type = PT_ARM_EXIDX;
phdr.p_offset = 0x30000;
phdr.p_vaddr = 0x30000;
phdr.p_paddr = 0x30000;
phdr.p_filesz = 16;
phdr.p_memsz = 16;
phdr.p_flags = PF_R;
phdr.p_align = 0x4;
memory_->SetMemory(0x100 + sizeof(phdr), &phdr, sizeof(phdr));
}
}
void InitElf64(uint32_t machine_type) {
Elf64_Ehdr ehdr;
TestInitEhdr<Elf64_Ehdr>(&ehdr, ELFCLASS64, machine_type);
ehdr.e_phoff = 0x100;
ehdr.e_flags = 0x5000200;
ehdr.e_ehsize = sizeof(ehdr);
ehdr.e_phentsize = sizeof(Elf64_Phdr);
ehdr.e_phnum = 1;
ehdr.e_shentsize = sizeof(Elf64_Shdr);
memory_->SetMemory(0, &ehdr, sizeof(ehdr));
Elf64_Phdr phdr;
memset(&phdr, 0, sizeof(phdr));
phdr.p_type = PT_LOAD;
phdr.p_filesz = 0x10000;
phdr.p_memsz = 0x10000;
phdr.p_flags = PF_R | PF_X;
phdr.p_align = 0x1000;
memory_->SetMemory(0x100, &phdr, sizeof(phdr));
}
MemoryFake* memory_;
};
TEST_F(ElfTest, invalid_memory) {
Elf elf(memory_);
ASSERT_FALSE(elf.Init(false));
ASSERT_FALSE(elf.valid());
}
TEST_F(ElfTest, elf_invalid) {
Elf elf(memory_);
InitElf32(EM_386);
// Corrupt the ELF signature.
memory_->SetData32(0, 0x7f000000);
ASSERT_FALSE(elf.Init(false));
ASSERT_FALSE(elf.valid());
ASSERT_TRUE(elf.interface() == nullptr);
std::string name;
ASSERT_FALSE(elf.GetSoname(&name));
uint64_t func_offset;
ASSERT_FALSE(elf.GetFunctionName(0, &name, &func_offset));
bool finished;
ASSERT_FALSE(elf.Step(0, 0, nullptr, nullptr, &finished));
}
TEST_F(ElfTest, elf32_invalid_machine) {
Elf elf(memory_);
InitElf32(EM_PPC);
ResetLogs();
ASSERT_FALSE(elf.Init(false));
ASSERT_EQ("", GetFakeLogBuf());
ASSERT_EQ("4 unwind 32 bit elf that is neither arm nor x86 nor mips: e_machine = 20\n\n",
GetFakeLogPrint());
}
TEST_F(ElfTest, elf64_invalid_machine) {
Elf elf(memory_);
InitElf64(EM_PPC64);
ResetLogs();
ASSERT_FALSE(elf.Init(false));
ASSERT_EQ("", GetFakeLogBuf());
ASSERT_EQ("4 unwind 64 bit elf that is neither aarch64 nor x86_64 nor mips64: e_machine = 21\n\n",
GetFakeLogPrint());
}
TEST_F(ElfTest, elf_arm) {
Elf elf(memory_);
InitElf32(EM_ARM);
ASSERT_TRUE(elf.Init(false));
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_ARM), elf.machine_type());
ASSERT_EQ(ELFCLASS32, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_mips) {
Elf elf(memory_);
InitElf32(EM_MIPS);
ASSERT_TRUE(elf.Init(false));
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_MIPS), elf.machine_type());
ASSERT_EQ(ELFCLASS32, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_x86) {
Elf elf(memory_);
InitElf32(EM_386);
ASSERT_TRUE(elf.Init(false));
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_386), elf.machine_type());
ASSERT_EQ(ELFCLASS32, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_arm64) {
Elf elf(memory_);
InitElf64(EM_AARCH64);
ASSERT_TRUE(elf.Init(false));
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_AARCH64), elf.machine_type());
ASSERT_EQ(ELFCLASS64, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_x86_64) {
Elf elf(memory_);
InitElf64(EM_X86_64);
ASSERT_TRUE(elf.Init(false));
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_X86_64), elf.machine_type());
ASSERT_EQ(ELFCLASS64, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, elf_mips64) {
Elf elf(memory_);
InitElf64(EM_MIPS);
ASSERT_TRUE(elf.Init(false));
ASSERT_TRUE(elf.valid());
ASSERT_EQ(static_cast<uint32_t>(EM_MIPS), elf.machine_type());
ASSERT_EQ(ELFCLASS64, elf.class_type());
ASSERT_TRUE(elf.interface() != nullptr);
}
TEST_F(ElfTest, gnu_debugdata_init_fail32) {
TestInitGnuDebugdata<Elf32_Ehdr, Elf32_Shdr>(ELFCLASS32, EM_ARM, false,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(offset, ptr, size);
});
Elf elf(memory_);
ASSERT_TRUE(elf.Init(false));
ASSERT_TRUE(elf.interface() != nullptr);
ASSERT_TRUE(elf.gnu_debugdata_interface() == nullptr);
EXPECT_EQ(0x1acU, elf.interface()->gnu_debugdata_offset());
EXPECT_EQ(0x100U, elf.interface()->gnu_debugdata_size());
}
TEST_F(ElfTest, gnu_debugdata_init_fail64) {
TestInitGnuDebugdata<Elf64_Ehdr, Elf64_Shdr>(ELFCLASS64, EM_AARCH64, false,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(offset, ptr, size);
});
Elf elf(memory_);
ASSERT_TRUE(elf.Init(false));
ASSERT_TRUE(elf.interface() != nullptr);
ASSERT_TRUE(elf.gnu_debugdata_interface() == nullptr);
EXPECT_EQ(0x200U, elf.interface()->gnu_debugdata_offset());
EXPECT_EQ(0x100U, elf.interface()->gnu_debugdata_size());
}
TEST_F(ElfTest, gnu_debugdata_init32) {
TestInitGnuDebugdata<Elf32_Ehdr, Elf32_Shdr>(ELFCLASS32, EM_ARM, true,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(offset, ptr, size);
});
Elf elf(memory_);
ASSERT_TRUE(elf.Init(true));
ASSERT_TRUE(elf.interface() != nullptr);
ASSERT_TRUE(elf.gnu_debugdata_interface() != nullptr);
EXPECT_EQ(0x1acU, elf.interface()->gnu_debugdata_offset());
EXPECT_EQ(0x8cU, elf.interface()->gnu_debugdata_size());
}
TEST_F(ElfTest, gnu_debugdata_init64) {
TestInitGnuDebugdata<Elf64_Ehdr, Elf64_Shdr>(ELFCLASS64, EM_AARCH64, true,
[&](uint64_t offset, const void* ptr, size_t size) {
memory_->SetMemory(offset, ptr, size);
});
Elf elf(memory_);
ASSERT_TRUE(elf.Init(true));
ASSERT_TRUE(elf.interface() != nullptr);
ASSERT_TRUE(elf.gnu_debugdata_interface() != nullptr);
EXPECT_EQ(0x200U, elf.interface()->gnu_debugdata_offset());
EXPECT_EQ(0x90U, elf.interface()->gnu_debugdata_size());
}
TEST_F(ElfTest, rel_pc) {
ElfFake elf(memory_);
ElfInterfaceFake* interface = new ElfInterfaceFake(memory_);
elf.FakeSetInterface(interface);
elf.FakeSetValid(true);
MapInfo map_info(0x1000, 0x2000);
ASSERT_EQ(0x101U, elf.GetRelPc(0x1101, &map_info));
elf.FakeSetValid(false);
ASSERT_EQ(0x101U, elf.GetRelPc(0x1101, &map_info));
}
TEST_F(ElfTest, step_in_signal_map) {
ElfFake elf(memory_);
RegsArm regs;
regs[13] = 0x50000;
regs[15] = 0x8000;
ElfInterfaceFake* interface = new ElfInterfaceFake(memory_);
elf.FakeSetInterface(interface);
memory_->SetData32(0x3000, 0xdf0027ad);
MemoryFake process_memory;
process_memory.SetData32(0x50000, 0);
for (size_t i = 0; i < 16; i++) {
process_memory.SetData32(0x500a0 + i * sizeof(uint32_t), i);
}
elf.FakeSetValid(true);
bool finished;
ASSERT_TRUE(elf.Step(0x3000, 0x1000, &regs, &process_memory, &finished));
EXPECT_FALSE(finished);
EXPECT_EQ(15U, regs.pc());
EXPECT_EQ(13U, regs.sp());
}
class ElfInterfaceMock : public ElfInterface {
public:
ElfInterfaceMock(Memory* memory) : ElfInterface(memory) {}
virtual ~ElfInterfaceMock() = default;
bool Init(uint64_t*) override { return false; }
void InitHeaders(uint64_t) override {}
bool GetSoname(std::string*) override { return false; }
bool GetFunctionName(uint64_t, std::string*, uint64_t*) override { return false; }
MOCK_METHOD4(Step, bool(uint64_t, Regs*, Memory*, bool*));
MOCK_METHOD2(GetGlobalVariable, bool(const std::string&, uint64_t*));
MOCK_METHOD1(IsValidPc, bool(uint64_t));
void MockSetDynamicOffset(uint64_t offset) { dynamic_offset_ = offset; }
void MockSetDynamicVaddr(uint64_t vaddr) { dynamic_vaddr_ = vaddr; }
void MockSetDynamicSize(uint64_t size) { dynamic_size_ = size; }
};
TEST_F(ElfTest, step_in_interface) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
RegsArm regs;
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
MemoryFake process_memory;
bool finished;
EXPECT_CALL(*interface, Step(0x1000, &regs, &process_memory, &finished))
.WillOnce(::testing::Return(true));
ASSERT_TRUE(elf.Step(0x1004, 0x1000, &regs, &process_memory, &finished));
}
TEST_F(ElfTest, get_global_invalid_elf) {
ElfFake elf(memory_);
elf.FakeSetValid(false);
std::string global("something");
uint64_t offset;
ASSERT_FALSE(elf.GetGlobalVariable(global, &offset));
}
TEST_F(ElfTest, get_global_valid_not_in_interface) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
uint64_t offset;
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, &offset)).WillOnce(::testing::Return(false));
ASSERT_FALSE(elf.GetGlobalVariable(global, &offset));
}
TEST_F(ElfTest, get_global_valid_below_load_bias) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
elf.FakeSetLoadBias(0x1000);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
uint64_t offset;
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, &offset))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x300), ::testing::Return(true)));
ASSERT_FALSE(elf.GetGlobalVariable(global, &offset));
}
TEST_F(ElfTest, get_global_valid_dynamic_zero_non_zero_load_bias) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
elf.FakeSetLoadBias(0x100);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
uint64_t offset;
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, &offset))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x300), ::testing::Return(true)));
ASSERT_TRUE(elf.GetGlobalVariable(global, &offset));
EXPECT_EQ(0x200U, offset);
}
TEST_F(ElfTest, get_global_valid_dynamic_zero) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
ElfInterfaceMock* gnu_interface = new ElfInterfaceMock(memory_);
elf.FakeSetGnuDebugdataInterface(gnu_interface);
uint64_t offset;
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, &offset)).WillOnce(::testing::Return(false));
EXPECT_CALL(*gnu_interface, GetGlobalVariable(global, &offset))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x500), ::testing::Return(true)));
ASSERT_TRUE(elf.GetGlobalVariable(global, &offset));
EXPECT_EQ(0x500U, offset);
}
TEST_F(ElfTest, get_global_valid_in_gnu_debugdata_dynamic_zero) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
uint64_t offset;
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, &offset))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x300), ::testing::Return(true)));
ASSERT_TRUE(elf.GetGlobalVariable(global, &offset));
EXPECT_EQ(0x300U, offset);
}
TEST_F(ElfTest, get_global_valid_dynamic_adjust_negative) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
interface->MockSetDynamicOffset(0x400);
interface->MockSetDynamicVaddr(0x800);
interface->MockSetDynamicSize(0x100);
elf.FakeSetInterface(interface);
uint64_t offset;
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, &offset))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x850), ::testing::Return(true)));
ASSERT_TRUE(elf.GetGlobalVariable(global, &offset));
EXPECT_EQ(0x450U, offset);
}
TEST_F(ElfTest, get_global_valid_dynamic_adjust_positive) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
interface->MockSetDynamicOffset(0x1000);
interface->MockSetDynamicVaddr(0x800);
interface->MockSetDynamicSize(0x100);
elf.FakeSetInterface(interface);
uint64_t offset;
std::string global("something");
EXPECT_CALL(*interface, GetGlobalVariable(global, &offset))
.WillOnce(::testing::DoAll(::testing::SetArgPointee<1>(0x850), ::testing::Return(true)));
ASSERT_TRUE(elf.GetGlobalVariable(global, &offset));
EXPECT_EQ(0x1050U, offset);
}
TEST_F(ElfTest, is_valid_pc_elf_invalid) {
ElfFake elf(memory_);
elf.FakeSetValid(false);
EXPECT_FALSE(elf.IsValidPc(0x100));
EXPECT_FALSE(elf.IsValidPc(0x200));
}
TEST_F(ElfTest, is_valid_pc_interface) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
EXPECT_CALL(*interface, IsValidPc(0x1500)).WillOnce(::testing::Return(true));
EXPECT_TRUE(elf.IsValidPc(0x1500));
}
TEST_F(ElfTest, is_valid_pc_from_gnu_debugdata) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceMock* interface = new ElfInterfaceMock(memory_);
elf.FakeSetInterface(interface);
ElfInterfaceMock* gnu_interface = new ElfInterfaceMock(memory_);
elf.FakeSetGnuDebugdataInterface(gnu_interface);
EXPECT_CALL(*interface, IsValidPc(0x1500)).WillOnce(::testing::Return(false));
EXPECT_CALL(*gnu_interface, IsValidPc(0x1500)).WillOnce(::testing::Return(true));
EXPECT_TRUE(elf.IsValidPc(0x1500));
}
TEST_F(ElfTest, error_code_not_valid) {
ElfFake elf(memory_);
elf.FakeSetValid(false);
ErrorData error{ERROR_MEMORY_INVALID, 0x100};
elf.GetLastError(&error);
EXPECT_EQ(ERROR_MEMORY_INVALID, error.code);
EXPECT_EQ(0x100U, error.address);
}
TEST_F(ElfTest, error_code_valid) {
ElfFake elf(memory_);
elf.FakeSetValid(true);
ElfInterfaceFake* interface = new ElfInterfaceFake(memory_);
elf.FakeSetInterface(interface);
interface->FakeSetErrorCode(ERROR_MEMORY_INVALID);
interface->FakeSetErrorAddress(0x1000);
ErrorData error{ERROR_NONE, 0};
elf.GetLastError(&error);
EXPECT_EQ(ERROR_MEMORY_INVALID, error.code);
EXPECT_EQ(0x1000U, error.address);
EXPECT_EQ(ERROR_MEMORY_INVALID, elf.GetLastErrorCode());
EXPECT_EQ(0x1000U, elf.GetLastErrorAddress());
}
} // namespace unwindstack
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