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/*
* Copyright (C) 2015 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 <inttypes.h>
#include <libunwind.h>
#include <pthread.h>
#include <stdint.h>
#include <string.h>
#include <functional>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include <android-base/file.h>
#include <android-base/stringprintf.h>
#include <android-base/strings.h>
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
#include <cutils/threads.h>
#include <gtest/gtest.h>
extern "C" {
// Prototypes for functions in the test library.
int test_level_one(int, int, int, int, void (*)(void*), void*);
int test_level_two(int, int, int, int, void (*)(void*), void*);
int test_level_three(int, int, int, int, void (*)(void*), void*);
int test_level_four(int, int, int, int, void (*)(void*), void*);
int test_recursive_call(int, void (*)(void*), void*);
void test_get_context_and_wait(unw_context_t* unw_context, volatile int* exit_flag);
}
static ucontext_t GetUContextFromUnwContext(const unw_context_t& unw_context) {
ucontext_t ucontext;
memset(&ucontext, 0, sizeof(ucontext));
#if defined(__arm__)
ucontext.uc_mcontext.arm_r0 = unw_context.regs[0];
ucontext.uc_mcontext.arm_r1 = unw_context.regs[1];
ucontext.uc_mcontext.arm_r2 = unw_context.regs[2];
ucontext.uc_mcontext.arm_r3 = unw_context.regs[3];
ucontext.uc_mcontext.arm_r4 = unw_context.regs[4];
ucontext.uc_mcontext.arm_r5 = unw_context.regs[5];
ucontext.uc_mcontext.arm_r6 = unw_context.regs[6];
ucontext.uc_mcontext.arm_r7 = unw_context.regs[7];
ucontext.uc_mcontext.arm_r8 = unw_context.regs[8];
ucontext.uc_mcontext.arm_r9 = unw_context.regs[9];
ucontext.uc_mcontext.arm_r10 = unw_context.regs[10];
ucontext.uc_mcontext.arm_fp = unw_context.regs[11];
ucontext.uc_mcontext.arm_ip = unw_context.regs[12];
ucontext.uc_mcontext.arm_sp = unw_context.regs[13];
ucontext.uc_mcontext.arm_lr = unw_context.regs[14];
ucontext.uc_mcontext.arm_pc = unw_context.regs[15];
#else
ucontext.uc_mcontext = unw_context.uc_mcontext;
#endif
return ucontext;
}
struct FunctionSymbol {
std::string name;
uintptr_t start;
uintptr_t end;
};
static std::vector<FunctionSymbol> GetFunctionSymbols() {
std::vector<FunctionSymbol> symbols = {
{"unknown_start", 0, 0},
{"test_level_one", reinterpret_cast<uintptr_t>(&test_level_one), 0},
{"test_level_two", reinterpret_cast<uintptr_t>(&test_level_two), 0},
{"test_level_three", reinterpret_cast<uintptr_t>(&test_level_three), 0},
{"test_level_four", reinterpret_cast<uintptr_t>(&test_level_four), 0},
{"test_recursive_call", reinterpret_cast<uintptr_t>(&test_recursive_call), 0},
{"test_get_context_and_wait", reinterpret_cast<uintptr_t>(&test_get_context_and_wait), 0},
{"unknown_end", static_cast<uintptr_t>(-1), static_cast<uintptr_t>(-1)},
};
std::sort(
symbols.begin(), symbols.end(),
[](const FunctionSymbol& s1, const FunctionSymbol& s2) { return s1.start < s2.start; });
for (size_t i = 0; i + 1 < symbols.size(); ++i) {
symbols[i].end = symbols[i + 1].start;
}
return symbols;
}
static std::string RawDataToHexString(const void* data, size_t size) {
const uint8_t* p = static_cast<const uint8_t*>(data);
std::string s;
for (size_t i = 0; i < size; ++i) {
s += android::base::StringPrintf("%02x", p[i]);
}
return s;
}
static void HexStringToRawData(const char* s, void* data, size_t size) {
uint8_t* p = static_cast<uint8_t*>(data);
for (size_t i = 0; i < size; ++i) {
int value;
sscanf(s, "%02x", &value);
*p++ = static_cast<uint8_t>(value);
s += 2;
}
}
struct OfflineThreadArg {
unw_context_t unw_context;
pid_t tid;
volatile int exit_flag;
};
static void* OfflineThreadFunc(void* arg) {
OfflineThreadArg* fn_arg = reinterpret_cast<OfflineThreadArg*>(arg);
fn_arg->tid = gettid();
test_get_context_and_wait(&fn_arg->unw_context, &fn_arg->exit_flag);
return nullptr;
}
// This test is disable because it is for generating test data.
TEST(libbacktrace, DISABLED_generate_offline_testdata) {
// Create a thread to generate the needed stack and registers information.
const size_t stack_size = 16 * 1024;
void* stack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
ASSERT_NE(MAP_FAILED, stack);
uintptr_t stack_addr = reinterpret_cast<uintptr_t>(stack);
pthread_attr_t attr;
ASSERT_EQ(0, pthread_attr_init(&attr));
ASSERT_EQ(0, pthread_attr_setstack(&attr, reinterpret_cast<void*>(stack), stack_size));
pthread_t thread;
OfflineThreadArg arg;
arg.exit_flag = 0;
ASSERT_EQ(0, pthread_create(&thread, &attr, OfflineThreadFunc, &arg));
// Wait for the offline thread to generate the stack and unw_context information.
sleep(1);
// Copy the stack information.
std::vector<uint8_t> stack_data(reinterpret_cast<uint8_t*>(stack),
reinterpret_cast<uint8_t*>(stack) + stack_size);
arg.exit_flag = 1;
ASSERT_EQ(0, pthread_join(thread, nullptr));
ASSERT_EQ(0, munmap(stack, stack_size));
std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(getpid()));
ASSERT_TRUE(map != nullptr);
backtrace_stackinfo_t stack_info;
stack_info.start = stack_addr;
stack_info.end = stack_addr + stack_size;
stack_info.data = stack_data.data();
// Generate offline testdata.
std::string testdata;
// 1. Dump pid, tid
testdata += android::base::StringPrintf("pid: %d tid: %d\n", getpid(), arg.tid);
// 2. Dump maps
for (auto it = map->begin(); it != map->end(); ++it) {
testdata += android::base::StringPrintf(
"map: start: %" PRIxPTR " end: %" PRIxPTR " offset: %" PRIxPTR " load_bias: %" PRIxPTR
" flags: %d name: %s\n",
it->start, it->end, it->offset, it->load_bias, it->flags, it->name.c_str());
}
// 3. Dump registers
testdata += android::base::StringPrintf("registers: %zu ", sizeof(arg.unw_context));
testdata += RawDataToHexString(&arg.unw_context, sizeof(arg.unw_context));
testdata.push_back('\n');
// 4. Dump stack
testdata += android::base::StringPrintf(
"stack: start: %" PRIx64 " end: %" PRIx64 " size: %zu ",
stack_info.start, stack_info.end, stack_data.size());
testdata += RawDataToHexString(stack_data.data(), stack_data.size());
testdata.push_back('\n');
// 5. Dump function symbols
std::vector<FunctionSymbol> function_symbols = GetFunctionSymbols();
for (const auto& symbol : function_symbols) {
testdata += android::base::StringPrintf(
"function: start: %" PRIxPTR " end: %" PRIxPTR" name: %s\n",
symbol.start, symbol.end, symbol.name.c_str());
}
ASSERT_TRUE(android::base::WriteStringToFile(testdata, "offline_testdata"));
}
// Return the name of the function which matches the address. Although we don't know the
// exact end of each function, it is accurate enough for the tests.
static std::string FunctionNameForAddress(uintptr_t addr,
const std::vector<FunctionSymbol>& symbols) {
for (auto& symbol : symbols) {
if (addr >= symbol.start && addr < symbol.end) {
return symbol.name;
}
}
return "";
}
static std::string GetArch() {
#if defined(__arm__)
return "arm";
#elif defined(__aarch64__)
return "aarch64";
#elif defined(__i386__)
return "x86";
#elif defined(__x86_64__)
return "x86_64";
#else
return "";
#endif
}
struct OfflineTestData {
int pid;
int tid;
std::vector<backtrace_map_t> maps;
unw_context_t unw_context;
backtrace_stackinfo_t stack_info;
std::vector<uint8_t> stack;
std::vector<FunctionSymbol> symbols;
};
bool ReadOfflineTestData(const std::string offline_testdata_path, OfflineTestData* testdata) {
std::string s;
if (!android::base::ReadFileToString(offline_testdata_path, &s)) {
return false;
}
// Parse offline_testdata.
std::vector<std::string> lines = android::base::Split(s, "\n");
memset(&testdata->unw_context, 0, sizeof(testdata->unw_context));
for (const auto& line : lines) {
if (android::base::StartsWith(line, "pid:")) {
sscanf(line.c_str(), "pid: %d tid: %d", &testdata->pid, &testdata->tid);
} else if (android::base::StartsWith(line, "map:")) {
testdata->maps.resize(testdata->maps.size() + 1);
backtrace_map_t& map = testdata->maps.back();
int pos;
sscanf(line.c_str(),
"map: start: %" SCNxPTR " end: %" SCNxPTR " offset: %" SCNxPTR " load_bias: %" SCNxPTR
" flags: %d name: %n",
&map.start, &map.end, &map.offset, &map.load_bias, &map.flags, &pos);
map.name = android::base::Trim(line.substr(pos));
} else if (android::base::StartsWith(line, "registers:")) {
size_t size;
int pos;
sscanf(line.c_str(), "registers: %zu %n", &size, &pos);
if (sizeof(testdata->unw_context) != size) {
return false;
}
HexStringToRawData(&line[pos], &testdata->unw_context, size);
} else if (android::base::StartsWith(line, "stack:")) {
size_t size;
int pos;
sscanf(line.c_str(),
"stack: start: %" SCNx64 " end: %" SCNx64 " size: %zu %n",
&testdata->stack_info.start, &testdata->stack_info.end, &size, &pos);
testdata->stack.resize(size);
HexStringToRawData(&line[pos], &testdata->stack[0], size);
testdata->stack_info.data = testdata->stack.data();
} else if (android::base::StartsWith(line, "function:")) {
testdata->symbols.resize(testdata->symbols.size() + 1);
FunctionSymbol& symbol = testdata->symbols.back();
int pos;
sscanf(line.c_str(),
"function: start: %" SCNxPTR " end: %" SCNxPTR " name: %n",
&symbol.start, &symbol.end, &pos);
symbol.name = line.substr(pos);
}
}
return true;
}
static void BacktraceOfflineTest(const std::string& testlib_name) {
const std::string arch = GetArch();
if (arch.empty()) {
GTEST_LOG_(INFO) << "This test does nothing on current arch.";
return;
}
const std::string testlib_path = "testdata/" + arch + "/" + testlib_name;
struct stat st;
if (stat(testlib_path.c_str(), &st) == -1) {
GTEST_LOG_(INFO) << "This test is skipped as " << testlib_path << " doesn't exist.";
return;
}
const std::string offline_testdata_path = "testdata/" + arch + "/offline_testdata";
OfflineTestData testdata;
ASSERT_TRUE(ReadOfflineTestData(offline_testdata_path, &testdata));
// Fix path of libbacktrace_testlib.so.
for (auto& map : testdata.maps) {
if (map.name.find("libbacktrace_test.so") != std::string::npos) {
map.name = testlib_path;
}
}
// Do offline backtrace.
std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(testdata.pid, testdata.maps));
ASSERT_TRUE(map != nullptr);
std::unique_ptr<Backtrace> backtrace(
Backtrace::CreateOffline(testdata.pid, testdata.tid, map.get(), testdata.stack_info));
ASSERT_TRUE(backtrace != nullptr);
ucontext_t ucontext = GetUContextFromUnwContext(testdata.unw_context);
ASSERT_TRUE(backtrace->Unwind(0, &ucontext));
// Collect pc values of the call stack frames.
std::vector<uintptr_t> pc_values;
for (size_t i = 0; i < backtrace->NumFrames(); ++i) {
pc_values.push_back(backtrace->GetFrame(i)->pc);
}
size_t test_one_index = 0;
for (size_t i = 0; i < pc_values.size(); ++i) {
if (FunctionNameForAddress(pc_values[i], testdata.symbols) == "test_level_one") {
test_one_index = i;
break;
}
}
ASSERT_GE(test_one_index, 3u);
ASSERT_EQ("test_level_one", FunctionNameForAddress(pc_values[test_one_index], testdata.symbols));
ASSERT_EQ("test_level_two", FunctionNameForAddress(pc_values[test_one_index - 1],
testdata.symbols));
ASSERT_EQ("test_level_three", FunctionNameForAddress(pc_values[test_one_index - 2],
testdata.symbols));
ASSERT_EQ("test_level_four", FunctionNameForAddress(pc_values[test_one_index - 3],
testdata.symbols));
}
TEST(libbacktrace, offline_eh_frame) {
BacktraceOfflineTest("libbacktrace_test_eh_frame.so");
}
TEST(libbacktrace, offline_debug_frame) {
BacktraceOfflineTest("libbacktrace_test_debug_frame.so");
}
TEST(libbacktrace, offline_gnu_debugdata) {
BacktraceOfflineTest("libbacktrace_test_gnu_debugdata.so");
}
TEST(libbacktrace, offline_arm_exidx) {
BacktraceOfflineTest("libbacktrace_test_arm_exidx.so");
}
// This test tests the situation that ranges of functions covered by .eh_frame and .ARM.exidx
// overlap with each other, which appears in /system/lib/libart.so.
TEST(libbacktrace, offline_unwind_mix_eh_frame_and_arm_exidx) {
const std::string arch = GetArch();
if (arch.empty() || arch != "arm") {
GTEST_LOG_(INFO) << "This test does nothing on current arch.";
return;
}
const std::string testlib_path = "testdata/" + arch + "/libart.so";
struct stat st;
ASSERT_EQ(0, stat(testlib_path.c_str(), &st)) << "can't find testlib " << testlib_path;
const std::string offline_testdata_path = "testdata/" + arch + "/offline_testdata_for_libart";
OfflineTestData testdata;
ASSERT_TRUE(ReadOfflineTestData(offline_testdata_path, &testdata));
// Fix path of /system/lib/libart.so.
for (auto& map : testdata.maps) {
if (map.name.find("libart.so") != std::string::npos) {
map.name = testlib_path;
}
}
// Do offline backtrace.
std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(testdata.pid, testdata.maps));
ASSERT_TRUE(map != nullptr);
std::unique_ptr<Backtrace> backtrace(
Backtrace::CreateOffline(testdata.pid, testdata.tid, map.get(), testdata.stack_info));
ASSERT_TRUE(backtrace != nullptr);
ucontext_t ucontext = GetUContextFromUnwContext(testdata.unw_context);
ASSERT_TRUE(backtrace->Unwind(0, &ucontext));
// The last frame is outside of libart.so
ASSERT_EQ(testdata.symbols.size() + 1, backtrace->NumFrames());
for (size_t i = 0; i + 1 < backtrace->NumFrames(); ++i) {
uintptr_t vaddr_in_file =
backtrace->GetFrame(i)->pc - testdata.maps[0].start + testdata.maps[0].load_bias;
std::string name = FunctionNameForAddress(vaddr_in_file, testdata.symbols);
ASSERT_EQ(name, testdata.symbols[i].name);
}
}