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android_system_core/libunwindstack/tests/ElfInterfaceArmTest.cpp
Christopher Ferris b9de87f7ed Add a new unwind method on error. 
If a function crashes by jumping into unexecutable code, the old method
could not unwind through that. Add a fallback method to set the pc from
the default return address location.

In addition, add a new finished check for steps. This will provide a method
to indicate that this step is the last step. This prevents cases where
the fallback method might be triggered incorrectly.

Update the libbacktrace code to unwind using the new methodology.

Update the unwind tool to use the new unwind methodology.

Add a new option to crasher that calls through a null function.

Create a new object, Unwinder, that encapsulates the a basic unwind. For now,
libbacktrace will still use the custom code.

Added new unit tests to cover the new cases. Also add a test that
crashes calling a nullptr as a function, and then has call frames in
the signal stack.

Bug: 65842173

Test: Pass all unit tests, verify crasher dumps properly.
Change-Id: Ia18430ab107e9f7bdf0e14a9b74710b1280bd7f4
2017-09-22 16:55:12 -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 <gtest/gtest.h>
#include <vector>
#include <unwindstack/Regs.h>
#include "ElfInterfaceArm.h"
#include "Machine.h"
#include "MemoryFake.h"
namespace unwindstack {
class ElfInterfaceArmTest : public ::testing::Test {
protected:
void SetUp() override {
memory_.Clear();
process_memory_.Clear();
}
MemoryFake memory_;
MemoryFake process_memory_;
};
TEST_F(ElfInterfaceArmTest, GetPrel32Addr) {
ElfInterfaceArm interface(&memory_);
memory_.SetData32(0x1000, 0x230000);
uint32_t value;
ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
ASSERT_EQ(0x231000U, value);
memory_.SetData32(0x1000, 0x80001000);
ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
ASSERT_EQ(0x2000U, value);
memory_.SetData32(0x1000, 0x70001000);
ASSERT_TRUE(interface.GetPrel31Addr(0x1000, &value));
ASSERT_EQ(0xf0002000U, value);
}
TEST_F(ElfInterfaceArmTest, FindEntry_start_zero) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0);
interface.set_total_entries(10);
uint64_t entry_offset;
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
}
TEST_F(ElfInterfaceArmTest, FindEntry_no_entries) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x100);
interface.set_total_entries(0);
uint64_t entry_offset;
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
}
TEST_F(ElfInterfaceArmTest, FindEntry_no_valid_memory) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x100);
interface.set_total_entries(2);
uint64_t entry_offset;
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
}
TEST_F(ElfInterfaceArmTest, FindEntry_ip_before_first) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(1);
memory_.SetData32(0x1000, 0x6000);
uint64_t entry_offset;
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
}
TEST_F(ElfInterfaceArmTest, FindEntry_single_entry_negative_value) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x8000);
interface.set_total_entries(1);
memory_.SetData32(0x8000, 0x7fffff00);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x7ff0, &entry_offset));
ASSERT_EQ(0x8000U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_two_entries) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x7000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x7000, &entry_offset));
ASSERT_EQ(0x1000U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_last_check_single_entry) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(1);
memory_.SetData32(0x1000, 0x6000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x7000, &entry_offset));
ASSERT_EQ(0x1000U, entry_offset);
// To guarantee that we are using the cache on the second run,
// set the memory to a different value.
memory_.SetData32(0x1000, 0x8000);
ASSERT_TRUE(interface.FindEntry(0x7004, &entry_offset));
ASSERT_EQ(0x1000U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_last_check_multiple_entries) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x8000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x9008, &entry_offset));
ASSERT_EQ(0x1008U, entry_offset);
// To guarantee that we are using the cache on the second run,
// set the memory to a different value.
memory_.SetData32(0x1000, 0x16000);
memory_.SetData32(0x1008, 0x18000);
ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
ASSERT_EQ(0x1008U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_multiple_entries_even) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(4);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x7000);
memory_.SetData32(0x1010, 0x8000);
memory_.SetData32(0x1018, 0x9000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
ASSERT_EQ(0x1010U, entry_offset);
// To guarantee that we are using the cache on the second run,
// set the memory to a different value.
memory_.SetData32(0x1000, 0x16000);
memory_.SetData32(0x1008, 0x17000);
memory_.SetData32(0x1010, 0x18000);
memory_.SetData32(0x1018, 0x19000);
ASSERT_TRUE(interface.FindEntry(0x9100, &entry_offset));
ASSERT_EQ(0x1010U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, FindEntry_multiple_entries_odd) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(5);
memory_.SetData32(0x1000, 0x5000);
memory_.SetData32(0x1008, 0x6000);
memory_.SetData32(0x1010, 0x7000);
memory_.SetData32(0x1018, 0x8000);
memory_.SetData32(0x1020, 0x9000);
uint64_t entry_offset;
ASSERT_TRUE(interface.FindEntry(0x8100, &entry_offset));
ASSERT_EQ(0x1010U, entry_offset);
// To guarantee that we are using the cache on the second run,
// set the memory to a different value.
memory_.SetData32(0x1000, 0x15000);
memory_.SetData32(0x1008, 0x16000);
memory_.SetData32(0x1010, 0x17000);
memory_.SetData32(0x1018, 0x18000);
memory_.SetData32(0x1020, 0x19000);
ASSERT_TRUE(interface.FindEntry(0x8100, &entry_offset));
ASSERT_EQ(0x1010U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, iterate) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(5);
memory_.SetData32(0x1000, 0x5000);
memory_.SetData32(0x1008, 0x6000);
memory_.SetData32(0x1010, 0x7000);
memory_.SetData32(0x1018, 0x8000);
memory_.SetData32(0x1020, 0x9000);
std::vector<uint32_t> entries;
for (auto addr : interface) {
entries.push_back(addr);
}
ASSERT_EQ(5U, entries.size());
ASSERT_EQ(0x6000U, entries[0]);
ASSERT_EQ(0x7008U, entries[1]);
ASSERT_EQ(0x8010U, entries[2]);
ASSERT_EQ(0x9018U, entries[3]);
ASSERT_EQ(0xa020U, entries[4]);
// Make sure the iterate cached the entries.
memory_.SetData32(0x1000, 0x11000);
memory_.SetData32(0x1008, 0x12000);
memory_.SetData32(0x1010, 0x13000);
memory_.SetData32(0x1018, 0x14000);
memory_.SetData32(0x1020, 0x15000);
entries.clear();
for (auto addr : interface) {
entries.push_back(addr);
}
ASSERT_EQ(5U, entries.size());
ASSERT_EQ(0x6000U, entries[0]);
ASSERT_EQ(0x7008U, entries[1]);
ASSERT_EQ(0x8010U, entries[2]);
ASSERT_EQ(0x9018U, entries[3]);
ASSERT_EQ(0xa020U, entries[4]);
}
TEST_F(ElfInterfaceArmTest, FindEntry_load_bias) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x8000);
uint64_t entry_offset;
interface.set_load_bias(0x2000);
ASSERT_FALSE(interface.FindEntry(0x1000, &entry_offset));
ASSERT_FALSE(interface.FindEntry(0x8000, &entry_offset));
ASSERT_FALSE(interface.FindEntry(0x8fff, &entry_offset));
ASSERT_TRUE(interface.FindEntry(0x9000, &entry_offset));
ASSERT_EQ(0x1000U, entry_offset);
ASSERT_TRUE(interface.FindEntry(0xb007, &entry_offset));
ASSERT_EQ(0x1000U, entry_offset);
ASSERT_TRUE(interface.FindEntry(0xb008, &entry_offset));
ASSERT_EQ(0x1008U, entry_offset);
}
TEST_F(ElfInterfaceArmTest, HandleType_not_arm_exidx) {
ElfInterfaceArm interface(&memory_);
ASSERT_FALSE(interface.HandleType(0x1000, PT_NULL));
ASSERT_FALSE(interface.HandleType(0x1000, PT_LOAD));
ASSERT_FALSE(interface.HandleType(0x1000, PT_DYNAMIC));
ASSERT_FALSE(interface.HandleType(0x1000, PT_INTERP));
ASSERT_FALSE(interface.HandleType(0x1000, PT_NOTE));
ASSERT_FALSE(interface.HandleType(0x1000, PT_SHLIB));
ASSERT_FALSE(interface.HandleType(0x1000, PT_PHDR));
ASSERT_FALSE(interface.HandleType(0x1000, PT_TLS));
ASSERT_FALSE(interface.HandleType(0x1000, PT_LOOS));
ASSERT_FALSE(interface.HandleType(0x1000, PT_HIOS));
ASSERT_FALSE(interface.HandleType(0x1000, PT_LOPROC));
ASSERT_FALSE(interface.HandleType(0x1000, PT_HIPROC));
ASSERT_FALSE(interface.HandleType(0x1000, PT_GNU_EH_FRAME));
ASSERT_FALSE(interface.HandleType(0x1000, PT_GNU_STACK));
}
TEST_F(ElfInterfaceArmTest, HandleType_arm_exidx) {
ElfInterfaceArm interface(&memory_);
Elf32_Phdr phdr;
interface.set_start_offset(0x1000);
interface.set_total_entries(100);
phdr.p_vaddr = 0x2000;
phdr.p_memsz = 0xa00;
// Verify that if reads fail, we don't set the values but still get true.
ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001));
ASSERT_EQ(0x1000U, interface.start_offset());
ASSERT_EQ(100U, interface.total_entries());
// Verify that if the second read fails, we still don't set the values.
memory_.SetData32(
0x1000 + reinterpret_cast<uint64_t>(&phdr.p_vaddr) - reinterpret_cast<uint64_t>(&phdr),
phdr.p_vaddr);
ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001));
ASSERT_EQ(0x1000U, interface.start_offset());
ASSERT_EQ(100U, interface.total_entries());
// Everything is correct and present.
memory_.SetData32(
0x1000 + reinterpret_cast<uint64_t>(&phdr.p_memsz) - reinterpret_cast<uint64_t>(&phdr),
phdr.p_memsz);
ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001));
ASSERT_EQ(0x2000U, interface.start_offset());
ASSERT_EQ(320U, interface.total_entries());
// Non-zero load bias.
interface.set_load_bias(0x1000);
ASSERT_TRUE(interface.HandleType(0x1000, 0x70000001));
ASSERT_EQ(0x1000U, interface.start_offset());
ASSERT_EQ(320U, interface.total_entries());
}
TEST_F(ElfInterfaceArmTest, StepExidx) {
ElfInterfaceArm interface(&memory_);
// FindEntry fails.
bool finished;
ASSERT_FALSE(interface.StepExidx(0x7000, nullptr, nullptr, &finished));
// ExtractEntry should fail.
interface.set_start_offset(0x1000);
interface.set_total_entries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1008, 0x8000);
RegsArm regs;
regs[ARM_REG_SP] = 0x1000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
ASSERT_FALSE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
// Eval should fail.
memory_.SetData32(0x1004, 0x81000000);
ASSERT_FALSE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
// Everything should pass.
memory_.SetData32(0x1004, 0x80b0b0b0);
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
ASSERT_FALSE(finished);
ASSERT_EQ(0x1000U, regs.sp());
ASSERT_EQ(0x1000U, regs[ARM_REG_SP]);
ASSERT_EQ(0x20000U, regs.pc());
ASSERT_EQ(0x20000U, regs[ARM_REG_PC]);
}
TEST_F(ElfInterfaceArmTest, StepExidx_pc_set) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(2);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1004, 0x808800b0);
memory_.SetData32(0x1008, 0x8000);
process_memory_.SetData32(0x10000, 0x10);
RegsArm regs;
regs[ARM_REG_SP] = 0x10000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
// Everything should pass.
bool finished;
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
ASSERT_FALSE(finished);
ASSERT_EQ(0x10004U, regs.sp());
ASSERT_EQ(0x10004U, regs[ARM_REG_SP]);
ASSERT_EQ(0x10U, regs.pc());
ASSERT_EQ(0x10U, regs[ARM_REG_PC]);
}
TEST_F(ElfInterfaceArmTest, StepExidx_cant_unwind) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(1);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1004, 1);
RegsArm regs;
regs[ARM_REG_SP] = 0x10000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
bool finished;
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
ASSERT_TRUE(finished);
ASSERT_EQ(0x10000U, regs.sp());
ASSERT_EQ(0x10000U, regs[ARM_REG_SP]);
ASSERT_EQ(0x1234U, regs.pc());
}
TEST_F(ElfInterfaceArmTest, StepExidx_refuse_unwind) {
ElfInterfaceArm interface(&memory_);
interface.set_start_offset(0x1000);
interface.set_total_entries(1);
memory_.SetData32(0x1000, 0x6000);
memory_.SetData32(0x1004, 0x808000b0);
RegsArm regs;
regs[ARM_REG_SP] = 0x10000;
regs[ARM_REG_LR] = 0x20000;
regs.set_sp(regs[ARM_REG_SP]);
regs.set_pc(0x1234);
bool finished;
ASSERT_TRUE(interface.StepExidx(0x7000, &regs, &process_memory_, &finished));
ASSERT_TRUE(finished);
ASSERT_EQ(0x10000U, regs.sp());
ASSERT_EQ(0x10000U, regs[ARM_REG_SP]);
ASSERT_EQ(0x1234U, regs.pc());
}
} // namespace unwindstack
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