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platform_system_core/libbacktrace/backtrace_test.cpp
Christopher Ferris 5ea2c1f20a Test unwinding through a signal handler. 
Also make backtrace_testlib.c C++.

Bug: 34468756
Test: Ran new unit test on host x86, host x86_64, angler (32 bit, 64 bit),
Test: fugu.
Change-Id: Ia810f596c2df56cd56e8ab17e6c19be0c48d737f
2017-03-23 16:16:02 -07:00

1804 lines
56 KiB
C++
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/*
* Copyright (C) 2013 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 <dirent.h>
#include <dlfcn.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <pthread.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>
#include <algorithm>
#include <list>
#include <memory>
#include <ostream>
#include <string>
#include <vector>
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
#include <android-base/macros.h>
#include <android-base/stringprintf.h>
#include <android-base/unique_fd.h>
#include <cutils/atomic.h>
#include <cutils/threads.h>
#include <gtest/gtest.h>
// For the THREAD_SIGNAL definition.
#include "BacktraceCurrent.h"
#include "backtrace_testlib.h"
#include "thread_utils.h"
// Number of microseconds per milliseconds.
#define US_PER_MSEC 1000
// Number of nanoseconds in a second.
#define NS_PER_SEC 1000000000ULL
// Number of simultaneous dumping operations to perform.
#define NUM_THREADS 40
// Number of simultaneous threads running in our forked process.
#define NUM_PTRACE_THREADS 5
struct thread_t {
pid_t tid;
int32_t state;
pthread_t threadId;
void* data;
};
struct dump_thread_t {
thread_t thread;
Backtrace* backtrace;
int32_t* now;
int32_t done;
};
static uint64_t NanoTime() {
struct timespec t = { 0, 0 };
clock_gettime(CLOCK_MONOTONIC, &t);
return static_cast<uint64_t>(t.tv_sec * NS_PER_SEC + t.tv_nsec);
}
static std::string DumpFrames(Backtrace* backtrace) {
if (backtrace->NumFrames() == 0) {
return " No frames to dump.\n";
}
std::string frame;
for (size_t i = 0; i < backtrace->NumFrames(); i++) {
frame += " " + backtrace->FormatFrameData(i) + '\n';
}
return frame;
}
static void WaitForStop(pid_t pid) {
uint64_t start = NanoTime();
siginfo_t si;
while (ptrace(PTRACE_GETSIGINFO, pid, 0, &si) < 0 && (errno == EINTR || errno == ESRCH)) {
if ((NanoTime() - start) > NS_PER_SEC) {
printf("The process did not get to a stopping point in 1 second.\n");
break;
}
usleep(US_PER_MSEC);
}
}
static void CreateRemoteProcess(pid_t* pid) {
if ((*pid = fork()) == 0) {
while (true)
;
_exit(0);
}
ASSERT_NE(-1, *pid);
ASSERT_TRUE(ptrace(PTRACE_ATTACH, *pid, 0, 0) == 0);
// Wait for the process to get to a stopping point.
WaitForStop(*pid);
}
static void FinishRemoteProcess(pid_t pid) {
ASSERT_TRUE(ptrace(PTRACE_DETACH, pid, 0, 0) == 0);
kill(pid, SIGKILL);
ASSERT_EQ(waitpid(pid, nullptr, 0), pid);
}
static bool ReadyLevelBacktrace(Backtrace* backtrace) {
// See if test_level_four is in the backtrace.
bool found = false;
for (Backtrace::const_iterator it = backtrace->begin(); it != backtrace->end(); ++it) {
if (it->func_name == "test_level_four") {
found = true;
break;
}
}
return found;
}
static void VerifyLevelDump(Backtrace* backtrace) {
ASSERT_GT(backtrace->NumFrames(), static_cast<size_t>(0))
<< DumpFrames(backtrace);
ASSERT_LT(backtrace->NumFrames(), static_cast<size_t>(MAX_BACKTRACE_FRAMES))
<< DumpFrames(backtrace);
// Look through the frames starting at the highest to find the
// frame we want.
size_t frame_num = 0;
for (size_t i = backtrace->NumFrames()-1; i > 2; i--) {
if (backtrace->GetFrame(i)->func_name == "test_level_one") {
frame_num = i;
break;
}
}
ASSERT_LT(static_cast<size_t>(0), frame_num) << DumpFrames(backtrace);
ASSERT_LE(static_cast<size_t>(3), frame_num) << DumpFrames(backtrace);
ASSERT_EQ(backtrace->GetFrame(frame_num)->func_name, "test_level_one")
<< DumpFrames(backtrace);
ASSERT_EQ(backtrace->GetFrame(frame_num-1)->func_name, "test_level_two")
<< DumpFrames(backtrace);
ASSERT_EQ(backtrace->GetFrame(frame_num-2)->func_name, "test_level_three")
<< DumpFrames(backtrace);
ASSERT_EQ(backtrace->GetFrame(frame_num-3)->func_name, "test_level_four")
<< DumpFrames(backtrace);
}
static void VerifyLevelBacktrace(void*) {
std::unique_ptr<Backtrace> backtrace(
Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
VerifyLevelDump(backtrace.get());
}
static bool ReadyMaxBacktrace(Backtrace* backtrace) {
return (backtrace->NumFrames() == MAX_BACKTRACE_FRAMES);
}
static void VerifyMaxDump(Backtrace* backtrace) {
ASSERT_EQ(backtrace->NumFrames(), static_cast<size_t>(MAX_BACKTRACE_FRAMES))
<< DumpFrames(backtrace);
// Verify that the last frame is our recursive call.
ASSERT_EQ(backtrace->GetFrame(MAX_BACKTRACE_FRAMES-1)->func_name, "test_recursive_call")
<< DumpFrames(backtrace);
}
static void VerifyMaxBacktrace(void*) {
std::unique_ptr<Backtrace> backtrace(
Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
VerifyMaxDump(backtrace.get());
}
static void ThreadSetState(void* data) {
thread_t* thread = reinterpret_cast<thread_t*>(data);
android_atomic_acquire_store(1, &thread->state);
volatile int i = 0;
while (thread->state) {
i++;
}
}
static bool WaitForNonZero(int32_t* value, uint64_t seconds) {
uint64_t start = NanoTime();
do {
if (android_atomic_acquire_load(value)) {
return true;
}
} while ((NanoTime() - start) < seconds * NS_PER_SEC);
return false;
}
TEST(libbacktrace, local_no_unwind_frames) {
// Verify that a local unwind does not include any frames within
// libunwind or libbacktrace.
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), getpid()));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
ASSERT_TRUE(backtrace->NumFrames() != 0);
for (const auto& frame : *backtrace ) {
if (BacktraceMap::IsValid(frame.map)) {
const std::string name = basename(frame.map.name.c_str());
ASSERT_TRUE(name != "libunwind.so" && name != "libbacktrace.so")
<< DumpFrames(backtrace.get());
}
break;
}
}
TEST(libbacktrace, local_trace) {
ASSERT_NE(test_level_one(1, 2, 3, 4, VerifyLevelBacktrace, nullptr), 0);
}
static void VerifyIgnoreFrames(Backtrace* bt_all, Backtrace* bt_ign1, Backtrace* bt_ign2,
const char* cur_proc) {
EXPECT_EQ(bt_all->NumFrames(), bt_ign1->NumFrames() + 1)
<< "All backtrace:\n" << DumpFrames(bt_all) << "Ignore 1 backtrace:\n" << DumpFrames(bt_ign1);
EXPECT_EQ(bt_all->NumFrames(), bt_ign2->NumFrames() + 2)
<< "All backtrace:\n" << DumpFrames(bt_all) << "Ignore 2 backtrace:\n" << DumpFrames(bt_ign2);
// Check all of the frames are the same > the current frame.
bool check = (cur_proc == nullptr);
for (size_t i = 0; i < bt_ign2->NumFrames(); i++) {
if (check) {
EXPECT_EQ(bt_ign2->GetFrame(i)->pc, bt_ign1->GetFrame(i+1)->pc);
EXPECT_EQ(bt_ign2->GetFrame(i)->sp, bt_ign1->GetFrame(i+1)->sp);
EXPECT_EQ(bt_ign2->GetFrame(i)->stack_size, bt_ign1->GetFrame(i+1)->stack_size);
EXPECT_EQ(bt_ign2->GetFrame(i)->pc, bt_all->GetFrame(i+2)->pc);
EXPECT_EQ(bt_ign2->GetFrame(i)->sp, bt_all->GetFrame(i+2)->sp);
EXPECT_EQ(bt_ign2->GetFrame(i)->stack_size, bt_all->GetFrame(i+2)->stack_size);
}
if (!check && bt_ign2->GetFrame(i)->func_name == cur_proc) {
check = true;
}
}
}
static void VerifyLevelIgnoreFrames(void*) {
std::unique_ptr<Backtrace> all(
Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(all.get() != nullptr);
ASSERT_TRUE(all->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, all->GetError());
std::unique_ptr<Backtrace> ign1(
Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(ign1.get() != nullptr);
ASSERT_TRUE(ign1->Unwind(1));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, ign1->GetError());
std::unique_ptr<Backtrace> ign2(
Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(ign2.get() != nullptr);
ASSERT_TRUE(ign2->Unwind(2));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, ign2->GetError());
VerifyIgnoreFrames(all.get(), ign1.get(), ign2.get(), "VerifyLevelIgnoreFrames");
}
TEST(libbacktrace, local_trace_ignore_frames) {
ASSERT_NE(test_level_one(1, 2, 3, 4, VerifyLevelIgnoreFrames, nullptr), 0);
}
TEST(libbacktrace, local_max_trace) {
ASSERT_NE(test_recursive_call(MAX_BACKTRACE_FRAMES+10, VerifyMaxBacktrace, nullptr), 0);
}
static void VerifyProcTest(pid_t pid, pid_t tid, bool share_map, bool (*ReadyFunc)(Backtrace*),
void (*VerifyFunc)(Backtrace*)) {
pid_t ptrace_tid;
if (tid < 0) {
ptrace_tid = pid;
} else {
ptrace_tid = tid;
}
uint64_t start = NanoTime();
bool verified = false;
std::string last_dump;
do {
usleep(US_PER_MSEC);
if (ptrace(PTRACE_ATTACH, ptrace_tid, 0, 0) == 0) {
// Wait for the process to get to a stopping point.
WaitForStop(ptrace_tid);
std::unique_ptr<BacktraceMap> map;
if (share_map) {
map.reset(BacktraceMap::Create(pid));
}
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, tid, map.get()));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
if (ReadyFunc(backtrace.get())) {
VerifyFunc(backtrace.get());
verified = true;
} else {
last_dump = DumpFrames(backtrace.get());
}
ASSERT_TRUE(ptrace(PTRACE_DETACH, ptrace_tid, 0, 0) == 0);
}
// If 5 seconds have passed, then we are done.
} while (!verified && (NanoTime() - start) <= 5 * NS_PER_SEC);
ASSERT_TRUE(verified) << "Last backtrace:\n" << last_dump;
}
TEST(libbacktrace, ptrace_trace) {
pid_t pid;
if ((pid = fork()) == 0) {
ASSERT_NE(test_level_one(1, 2, 3, 4, nullptr, nullptr), 0);
_exit(1);
}
VerifyProcTest(pid, BACKTRACE_CURRENT_THREAD, false, ReadyLevelBacktrace, VerifyLevelDump);
kill(pid, SIGKILL);
int status;
ASSERT_EQ(waitpid(pid, &status, 0), pid);
}
TEST(libbacktrace, ptrace_trace_shared_map) {
pid_t pid;
if ((pid = fork()) == 0) {
ASSERT_NE(test_level_one(1, 2, 3, 4, nullptr, nullptr), 0);
_exit(1);
}
VerifyProcTest(pid, BACKTRACE_CURRENT_THREAD, true, ReadyLevelBacktrace, VerifyLevelDump);
kill(pid, SIGKILL);
int status;
ASSERT_EQ(waitpid(pid, &status, 0), pid);
}
TEST(libbacktrace, ptrace_max_trace) {
pid_t pid;
if ((pid = fork()) == 0) {
ASSERT_NE(test_recursive_call(MAX_BACKTRACE_FRAMES+10, nullptr, nullptr), 0);
_exit(1);
}
VerifyProcTest(pid, BACKTRACE_CURRENT_THREAD, false, ReadyMaxBacktrace, VerifyMaxDump);
kill(pid, SIGKILL);
int status;
ASSERT_EQ(waitpid(pid, &status, 0), pid);
}
static void VerifyProcessIgnoreFrames(Backtrace* bt_all) {
std::unique_ptr<Backtrace> ign1(Backtrace::Create(bt_all->Pid(), BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(ign1.get() != nullptr);
ASSERT_TRUE(ign1->Unwind(1));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, ign1->GetError());
std::unique_ptr<Backtrace> ign2(Backtrace::Create(bt_all->Pid(), BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(ign2.get() != nullptr);
ASSERT_TRUE(ign2->Unwind(2));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, ign2->GetError());
VerifyIgnoreFrames(bt_all, ign1.get(), ign2.get(), nullptr);
}
TEST(libbacktrace, ptrace_ignore_frames) {
pid_t pid;
if ((pid = fork()) == 0) {
ASSERT_NE(test_level_one(1, 2, 3, 4, nullptr, nullptr), 0);
_exit(1);
}
VerifyProcTest(pid, BACKTRACE_CURRENT_THREAD, false, ReadyLevelBacktrace, VerifyProcessIgnoreFrames);
kill(pid, SIGKILL);
int status;
ASSERT_EQ(waitpid(pid, &status, 0), pid);
}
// Create a process with multiple threads and dump all of the threads.
static void* PtraceThreadLevelRun(void*) {
EXPECT_NE(test_level_one(1, 2, 3, 4, nullptr, nullptr), 0);
return nullptr;
}
static void GetThreads(pid_t pid, std::vector<pid_t>* threads) {
// Get the list of tasks.
char task_path[128];
snprintf(task_path, sizeof(task_path), "/proc/%d/task", pid);
std::unique_ptr<DIR, decltype(&closedir)> tasks_dir(opendir(task_path), closedir);
ASSERT_TRUE(tasks_dir != nullptr);
struct dirent* entry;
while ((entry = readdir(tasks_dir.get())) != nullptr) {
char* end;
pid_t tid = strtoul(entry->d_name, &end, 10);
if (*end == '\0') {
threads->push_back(tid);
}
}
}
TEST(libbacktrace, ptrace_threads) {
pid_t pid;
if ((pid = fork()) == 0) {
for (size_t i = 0; i < NUM_PTRACE_THREADS; i++) {
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
pthread_t thread;
ASSERT_TRUE(pthread_create(&thread, &attr, PtraceThreadLevelRun, nullptr) == 0);
}
ASSERT_NE(test_level_one(1, 2, 3, 4, nullptr, nullptr), 0);
_exit(1);
}
// Check to see that all of the threads are running before unwinding.
std::vector<pid_t> threads;
uint64_t start = NanoTime();
do {
usleep(US_PER_MSEC);
threads.clear();
GetThreads(pid, &threads);
} while ((threads.size() != NUM_PTRACE_THREADS + 1) &&
((NanoTime() - start) <= 5 * NS_PER_SEC));
ASSERT_EQ(threads.size(), static_cast<size_t>(NUM_PTRACE_THREADS + 1));
ASSERT_TRUE(ptrace(PTRACE_ATTACH, pid, 0, 0) == 0);
WaitForStop(pid);
for (std::vector<int>::const_iterator it = threads.begin(); it != threads.end(); ++it) {
// Skip the current forked process, we only care about the threads.
if (pid == *it) {
continue;
}
VerifyProcTest(pid, *it, false, ReadyLevelBacktrace, VerifyLevelDump);
}
FinishRemoteProcess(pid);
}
void VerifyLevelThread(void*) {
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), gettid()));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
VerifyLevelDump(backtrace.get());
}
TEST(libbacktrace, thread_current_level) {
ASSERT_NE(test_level_one(1, 2, 3, 4, VerifyLevelThread, nullptr), 0);
}
static void VerifyMaxThread(void*) {
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), gettid()));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
VerifyMaxDump(backtrace.get());
}
TEST(libbacktrace, thread_current_max) {
ASSERT_NE(test_recursive_call(MAX_BACKTRACE_FRAMES+10, VerifyMaxThread, nullptr), 0);
}
static void* ThreadLevelRun(void* data) {
thread_t* thread = reinterpret_cast<thread_t*>(data);
thread->tid = gettid();
EXPECT_NE(test_level_one(1, 2, 3, 4, ThreadSetState, data), 0);
return nullptr;
}
TEST(libbacktrace, thread_level_trace) {
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
thread_t thread_data = { 0, 0, 0, nullptr };
pthread_t thread;
ASSERT_TRUE(pthread_create(&thread, &attr, ThreadLevelRun, &thread_data) == 0);
// Wait up to 2 seconds for the tid to be set.
ASSERT_TRUE(WaitForNonZero(&thread_data.state, 2));
// Make sure that the thread signal used is not visible when compiled for
// the target.
#if !defined(__GLIBC__)
ASSERT_LT(THREAD_SIGNAL, SIGRTMIN);
#endif
// Save the current signal action and make sure it is restored afterwards.
struct sigaction cur_action;
ASSERT_TRUE(sigaction(THREAD_SIGNAL, nullptr, &cur_action) == 0);
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), thread_data.tid));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
VerifyLevelDump(backtrace.get());
// Tell the thread to exit its infinite loop.
android_atomic_acquire_store(0, &thread_data.state);
// Verify that the old action was restored.
struct sigaction new_action;
ASSERT_TRUE(sigaction(THREAD_SIGNAL, nullptr, &new_action) == 0);
EXPECT_EQ(cur_action.sa_sigaction, new_action.sa_sigaction);
// The SA_RESTORER flag gets set behind our back, so a direct comparison
// doesn't work unless we mask the value off. Mips doesn't have this
// flag, so skip this on that platform.
#if defined(SA_RESTORER)
cur_action.sa_flags &= ~SA_RESTORER;
new_action.sa_flags &= ~SA_RESTORER;
#elif defined(__GLIBC__)
// Our host compiler doesn't appear to define this flag for some reason.
cur_action.sa_flags &= ~0x04000000;
new_action.sa_flags &= ~0x04000000;
#endif
EXPECT_EQ(cur_action.sa_flags, new_action.sa_flags);
}
TEST(libbacktrace, thread_ignore_frames) {
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
thread_t thread_data = { 0, 0, 0, nullptr };
pthread_t thread;
ASSERT_TRUE(pthread_create(&thread, &attr, ThreadLevelRun, &thread_data) == 0);
// Wait up to 2 seconds for the tid to be set.
ASSERT_TRUE(WaitForNonZero(&thread_data.state, 2));
std::unique_ptr<Backtrace> all(Backtrace::Create(getpid(), thread_data.tid));
ASSERT_TRUE(all.get() != nullptr);
ASSERT_TRUE(all->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, all->GetError());
std::unique_ptr<Backtrace> ign1(Backtrace::Create(getpid(), thread_data.tid));
ASSERT_TRUE(ign1.get() != nullptr);
ASSERT_TRUE(ign1->Unwind(1));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, ign1->GetError());
std::unique_ptr<Backtrace> ign2(Backtrace::Create(getpid(), thread_data.tid));
ASSERT_TRUE(ign2.get() != nullptr);
ASSERT_TRUE(ign2->Unwind(2));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, ign2->GetError());
VerifyIgnoreFrames(all.get(), ign1.get(), ign2.get(), nullptr);
// Tell the thread to exit its infinite loop.
android_atomic_acquire_store(0, &thread_data.state);
}
static void* ThreadMaxRun(void* data) {
thread_t* thread = reinterpret_cast<thread_t*>(data);
thread->tid = gettid();
EXPECT_NE(test_recursive_call(MAX_BACKTRACE_FRAMES+10, ThreadSetState, data), 0);
return nullptr;
}
TEST(libbacktrace, thread_max_trace) {
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
thread_t thread_data = { 0, 0, 0, nullptr };
pthread_t thread;
ASSERT_TRUE(pthread_create(&thread, &attr, ThreadMaxRun, &thread_data) == 0);
// Wait for the tid to be set.
ASSERT_TRUE(WaitForNonZero(&thread_data.state, 2));
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), thread_data.tid));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
VerifyMaxDump(backtrace.get());
// Tell the thread to exit its infinite loop.
android_atomic_acquire_store(0, &thread_data.state);
}
static void* ThreadDump(void* data) {
dump_thread_t* dump = reinterpret_cast<dump_thread_t*>(data);
while (true) {
if (android_atomic_acquire_load(dump->now)) {
break;
}
}
// The status of the actual unwind will be checked elsewhere.
dump->backtrace = Backtrace::Create(getpid(), dump->thread.tid);
dump->backtrace->Unwind(0);
android_atomic_acquire_store(1, &dump->done);
return nullptr;
}
TEST(libbacktrace, thread_multiple_dump) {
// Dump NUM_THREADS simultaneously.
std::vector<thread_t> runners(NUM_THREADS);
std::vector<dump_thread_t> dumpers(NUM_THREADS);
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
for (size_t i = 0; i < NUM_THREADS; i++) {
// Launch the runners, they will spin in hard loops doing nothing.
runners[i].tid = 0;
runners[i].state = 0;
ASSERT_TRUE(pthread_create(&runners[i].threadId, &attr, ThreadMaxRun, &runners[i]) == 0);
}
// Wait for tids to be set.
for (std::vector<thread_t>::iterator it = runners.begin(); it != runners.end(); ++it) {
ASSERT_TRUE(WaitForNonZero(&it->state, 30));
}
// Start all of the dumpers at once, they will spin until they are signalled
// to begin their dump run.
int32_t dump_now = 0;
for (size_t i = 0; i < NUM_THREADS; i++) {
dumpers[i].thread.tid = runners[i].tid;
dumpers[i].thread.state = 0;
dumpers[i].done = 0;
dumpers[i].now = &dump_now;
ASSERT_TRUE(pthread_create(&dumpers[i].thread.threadId, &attr, ThreadDump, &dumpers[i]) == 0);
}
// Start all of the dumpers going at once.
android_atomic_acquire_store(1, &dump_now);
for (size_t i = 0; i < NUM_THREADS; i++) {
ASSERT_TRUE(WaitForNonZero(&dumpers[i].done, 30));
// Tell the runner thread to exit its infinite loop.
android_atomic_acquire_store(0, &runners[i].state);
ASSERT_TRUE(dumpers[i].backtrace != nullptr);
VerifyMaxDump(dumpers[i].backtrace);
delete dumpers[i].backtrace;
dumpers[i].backtrace = nullptr;
}
}
TEST(libbacktrace, thread_multiple_dump_same_thread) {
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
thread_t runner;
runner.tid = 0;
runner.state = 0;
ASSERT_TRUE(pthread_create(&runner.threadId, &attr, ThreadMaxRun, &runner) == 0);
// Wait for tids to be set.
ASSERT_TRUE(WaitForNonZero(&runner.state, 30));
// Start all of the dumpers at once, they will spin until they are signalled
// to begin their dump run.
int32_t dump_now = 0;
// Dump the same thread NUM_THREADS simultaneously.
std::vector<dump_thread_t> dumpers(NUM_THREADS);
for (size_t i = 0; i < NUM_THREADS; i++) {
dumpers[i].thread.tid = runner.tid;
dumpers[i].thread.state = 0;
dumpers[i].done = 0;
dumpers[i].now = &dump_now;
ASSERT_TRUE(pthread_create(&dumpers[i].thread.threadId, &attr, ThreadDump, &dumpers[i]) == 0);
}
// Start all of the dumpers going at once.
android_atomic_acquire_store(1, &dump_now);
for (size_t i = 0; i < NUM_THREADS; i++) {
ASSERT_TRUE(WaitForNonZero(&dumpers[i].done, 30));
ASSERT_TRUE(dumpers[i].backtrace != nullptr);
VerifyMaxDump(dumpers[i].backtrace);
delete dumpers[i].backtrace;
dumpers[i].backtrace = nullptr;
}
// Tell the runner thread to exit its infinite loop.
android_atomic_acquire_store(0, &runner.state);
}
// This test is for UnwindMaps that should share the same map cursor when
// multiple maps are created for the current process at the same time.
TEST(libbacktrace, simultaneous_maps) {
BacktraceMap* map1 = BacktraceMap::Create(getpid());
BacktraceMap* map2 = BacktraceMap::Create(getpid());
BacktraceMap* map3 = BacktraceMap::Create(getpid());
Backtrace* back1 = Backtrace::Create(getpid(), BACKTRACE_CURRENT_THREAD, map1);
ASSERT_TRUE(back1 != nullptr);
EXPECT_TRUE(back1->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, back1->GetError());
delete back1;
delete map1;
Backtrace* back2 = Backtrace::Create(getpid(), BACKTRACE_CURRENT_THREAD, map2);
ASSERT_TRUE(back2 != nullptr);
EXPECT_TRUE(back2->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, back2->GetError());
delete back2;
delete map2;
Backtrace* back3 = Backtrace::Create(getpid(), BACKTRACE_CURRENT_THREAD, map3);
ASSERT_TRUE(back3 != nullptr);
EXPECT_TRUE(back3->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, back3->GetError());
delete back3;
delete map3;
}
TEST(libbacktrace, fillin_erases) {
BacktraceMap* back_map = BacktraceMap::Create(getpid());
backtrace_map_t map;
map.start = 1;
map.end = 3;
map.flags = 1;
map.name = "Initialized";
back_map->FillIn(0, &map);
delete back_map;
ASSERT_FALSE(BacktraceMap::IsValid(map));
ASSERT_EQ(static_cast<uintptr_t>(0), map.start);
ASSERT_EQ(static_cast<uintptr_t>(0), map.end);
ASSERT_EQ(0, map.flags);
ASSERT_EQ("", map.name);
}
TEST(libbacktrace, format_test) {
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace.get() != nullptr);
backtrace_frame_data_t frame;
frame.num = 1;
frame.pc = 2;
frame.sp = 0;
frame.stack_size = 0;
frame.func_offset = 0;
// Check no map set.
frame.num = 1;
#if defined(__LP64__)
EXPECT_EQ("#01 pc 0000000000000002 <unknown>",
#else
EXPECT_EQ("#01 pc 00000002 <unknown>",
#endif
backtrace->FormatFrameData(&frame));
// Check map name empty, but exists.
frame.pc = 0xb0020;
frame.map.start = 0xb0000;
frame.map.end = 0xbffff;
frame.map.load_base = 0;
#if defined(__LP64__)
EXPECT_EQ("#01 pc 0000000000000020 <anonymous:00000000000b0000>",
#else
EXPECT_EQ("#01 pc 00000020 <anonymous:000b0000>",
#endif
backtrace->FormatFrameData(&frame));
// Check map name begins with a [.
frame.pc = 0xc0020;
frame.map.start = 0xc0000;
frame.map.end = 0xcffff;
frame.map.load_base = 0;
frame.map.name = "[anon:thread signal stack]";
#if defined(__LP64__)
EXPECT_EQ("#01 pc 0000000000000020 [anon:thread signal stack:00000000000c0000]",
#else
EXPECT_EQ("#01 pc 00000020 [anon:thread signal stack:000c0000]",
#endif
backtrace->FormatFrameData(&frame));
// Check relative pc is set and map name is set.
frame.pc = 0x12345679;
frame.map.name = "MapFake";
frame.map.start = 1;
frame.map.end = 1;
#if defined(__LP64__)
EXPECT_EQ("#01 pc 0000000012345678 MapFake",
#else
EXPECT_EQ("#01 pc 12345678 MapFake",
#endif
backtrace->FormatFrameData(&frame));
// Check func_name is set, but no func offset.
frame.func_name = "ProcFake";
#if defined(__LP64__)
EXPECT_EQ("#01 pc 0000000012345678 MapFake (ProcFake)",
#else
EXPECT_EQ("#01 pc 12345678 MapFake (ProcFake)",
#endif
backtrace->FormatFrameData(&frame));
// Check func_name is set, and func offset is non-zero.
frame.func_offset = 645;
#if defined(__LP64__)
EXPECT_EQ("#01 pc 0000000012345678 MapFake (ProcFake+645)",
#else
EXPECT_EQ("#01 pc 12345678 MapFake (ProcFake+645)",
#endif
backtrace->FormatFrameData(&frame));
// Check func_name is set, func offset is non-zero, and load_base is non-zero.
frame.func_offset = 645;
frame.map.load_base = 100;
#if defined(__LP64__)
EXPECT_EQ("#01 pc 00000000123456dc MapFake (ProcFake+645)",
#else
EXPECT_EQ("#01 pc 123456dc MapFake (ProcFake+645)",
#endif
backtrace->FormatFrameData(&frame));
// Check a non-zero map offset.
frame.map.offset = 0x1000;
#if defined(__LP64__)
EXPECT_EQ("#01 pc 00000000123456dc MapFake (offset 0x1000) (ProcFake+645)",
#else
EXPECT_EQ("#01 pc 123456dc MapFake (offset 0x1000) (ProcFake+645)",
#endif
backtrace->FormatFrameData(&frame));
}
struct map_test_t {
uintptr_t start;
uintptr_t end;
};
static bool map_sort(map_test_t i, map_test_t j) { return i.start < j.start; }
static void VerifyMap(pid_t pid) {
char buffer[4096];
snprintf(buffer, sizeof(buffer), "/proc/%d/maps", pid);
FILE* map_file = fopen(buffer, "r");
ASSERT_TRUE(map_file != nullptr);
std::vector<map_test_t> test_maps;
while (fgets(buffer, sizeof(buffer), map_file)) {
map_test_t map;
ASSERT_EQ(2, sscanf(buffer, "%" SCNxPTR "-%" SCNxPTR " ", &map.start, &map.end));
test_maps.push_back(map);
}
fclose(map_file);
std::sort(test_maps.begin(), test_maps.end(), map_sort);
std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(pid));
// Basic test that verifies that the map is in the expected order.
ScopedBacktraceMapIteratorLock lock(map.get());
std::vector<map_test_t>::const_iterator test_it = test_maps.begin();
for (BacktraceMap::const_iterator it = map->begin(); it != map->end(); ++it) {
ASSERT_TRUE(test_it != test_maps.end());
ASSERT_EQ(test_it->start, it->start);
ASSERT_EQ(test_it->end, it->end);
++test_it;
}
ASSERT_TRUE(test_it == test_maps.end());
}
TEST(libbacktrace, verify_map_remote) {
pid_t pid;
CreateRemoteProcess(&pid);
// The maps should match exactly since the forked process has been paused.
VerifyMap(pid);
FinishRemoteProcess(pid);
}
static void InitMemory(uint8_t* memory, size_t bytes) {
for (size_t i = 0; i < bytes; i++) {
memory[i] = i;
if (memory[i] == '\0') {
// Don't use '\0' in our data so we can verify that an overread doesn't
// occur by using a '\0' as the character after the read data.
memory[i] = 23;
}
}
}
static void* ThreadReadTest(void* data) {
thread_t* thread_data = reinterpret_cast<thread_t*>(data);
thread_data->tid = gettid();
// Create two map pages.
// Mark the second page as not-readable.
size_t pagesize = static_cast<size_t>(sysconf(_SC_PAGE_SIZE));
uint8_t* memory;
if (posix_memalign(reinterpret_cast<void**>(&memory), pagesize, 2 * pagesize) != 0) {
return reinterpret_cast<void*>(-1);
}
if (mprotect(&memory[pagesize], pagesize, PROT_NONE) != 0) {
return reinterpret_cast<void*>(-1);
}
// Set up a simple pattern in memory.
InitMemory(memory, pagesize);
thread_data->data = memory;
// Tell the caller it's okay to start reading memory.
android_atomic_acquire_store(1, &thread_data->state);
// Loop waiting for the caller to finish reading the memory.
while (thread_data->state) {
}
// Re-enable read-write on the page so that we don't crash if we try
// and access data on this page when freeing the memory.
if (mprotect(&memory[pagesize], pagesize, PROT_READ | PROT_WRITE) != 0) {
return reinterpret_cast<void*>(-1);
}
free(memory);
android_atomic_acquire_store(1, &thread_data->state);
return nullptr;
}
static void RunReadTest(Backtrace* backtrace, uintptr_t read_addr) {
size_t pagesize = static_cast<size_t>(sysconf(_SC_PAGE_SIZE));
// Create a page of data to use to do quick compares.
uint8_t* expected = new uint8_t[pagesize];
InitMemory(expected, pagesize);
uint8_t* data = new uint8_t[2*pagesize];
// Verify that we can only read one page worth of data.
size_t bytes_read = backtrace->Read(read_addr, data, 2 * pagesize);
ASSERT_EQ(pagesize, bytes_read);
ASSERT_TRUE(memcmp(data, expected, pagesize) == 0);
// Verify unaligned reads.
for (size_t i = 1; i < sizeof(word_t); i++) {
bytes_read = backtrace->Read(read_addr + i, data, 2 * sizeof(word_t));
ASSERT_EQ(2 * sizeof(word_t), bytes_read);
ASSERT_TRUE(memcmp(data, &expected[i], 2 * sizeof(word_t)) == 0)
<< "Offset at " << i << " failed";
}
// Verify small unaligned reads.
for (size_t i = 1; i < sizeof(word_t); i++) {
for (size_t j = 1; j < sizeof(word_t); j++) {
// Set one byte past what we expect to read, to guarantee we don't overread.
data[j] = '\0';
bytes_read = backtrace->Read(read_addr + i, data, j);
ASSERT_EQ(j, bytes_read);
ASSERT_TRUE(memcmp(data, &expected[i], j) == 0)
<< "Offset at " << i << " length " << j << " miscompared";
ASSERT_EQ('\0', data[j])
<< "Offset at " << i << " length " << j << " wrote too much data";
}
}
delete[] data;
delete[] expected;
}
TEST(libbacktrace, thread_read) {
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
pthread_t thread;
thread_t thread_data = { 0, 0, 0, nullptr };
ASSERT_TRUE(pthread_create(&thread, &attr, ThreadReadTest, &thread_data) == 0);
ASSERT_TRUE(WaitForNonZero(&thread_data.state, 10));
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(getpid(), thread_data.tid));
ASSERT_TRUE(backtrace.get() != nullptr);
RunReadTest(backtrace.get(), reinterpret_cast<uintptr_t>(thread_data.data));
android_atomic_acquire_store(0, &thread_data.state);
ASSERT_TRUE(WaitForNonZero(&thread_data.state, 10));
}
volatile uintptr_t g_ready = 0;
volatile uintptr_t g_addr = 0;
static void ForkedReadTest() {
// Create two map pages.
size_t pagesize = static_cast<size_t>(sysconf(_SC_PAGE_SIZE));
uint8_t* memory;
if (posix_memalign(reinterpret_cast<void**>(&memory), pagesize, 2 * pagesize) != 0) {
perror("Failed to allocate memory\n");
exit(1);
}
// Mark the second page as not-readable.
if (mprotect(&memory[pagesize], pagesize, PROT_NONE) != 0) {
perror("Failed to mprotect memory\n");
exit(1);
}
// Set up a simple pattern in memory.
InitMemory(memory, pagesize);
g_addr = reinterpret_cast<uintptr_t>(memory);
g_ready = 1;
while (1) {
usleep(US_PER_MSEC);
}
}
TEST(libbacktrace, process_read) {
g_ready = 0;
pid_t pid;
if ((pid = fork()) == 0) {
ForkedReadTest();
exit(0);
}
ASSERT_NE(-1, pid);
bool test_executed = false;
uint64_t start = NanoTime();
while (1) {
if (ptrace(PTRACE_ATTACH, pid, 0, 0) == 0) {
WaitForStop(pid);
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, pid));
ASSERT_TRUE(backtrace.get() != nullptr);
uintptr_t read_addr;
size_t bytes_read = backtrace->Read(reinterpret_cast<uintptr_t>(&g_ready),
reinterpret_cast<uint8_t*>(&read_addr),
sizeof(uintptr_t));
ASSERT_EQ(sizeof(uintptr_t), bytes_read);
if (read_addr) {
// The forked process is ready to be read.
bytes_read = backtrace->Read(reinterpret_cast<uintptr_t>(&g_addr),
reinterpret_cast<uint8_t*>(&read_addr),
sizeof(uintptr_t));
ASSERT_EQ(sizeof(uintptr_t), bytes_read);
RunReadTest(backtrace.get(), read_addr);
test_executed = true;
break;
}
ASSERT_TRUE(ptrace(PTRACE_DETACH, pid, 0, 0) == 0);
}
if ((NanoTime() - start) > 5 * NS_PER_SEC) {
break;
}
usleep(US_PER_MSEC);
}
kill(pid, SIGKILL);
ASSERT_EQ(waitpid(pid, nullptr, 0), pid);
ASSERT_TRUE(test_executed);
}
static void VerifyFunctionsFound(const std::vector<std::string>& found_functions) {
// We expect to find these functions in libbacktrace_test. If we don't
// find them, that's a bug in the memory read handling code in libunwind.
std::list<std::string> expected_functions;
expected_functions.push_back("test_recursive_call");
expected_functions.push_back("test_level_one");
expected_functions.push_back("test_level_two");
expected_functions.push_back("test_level_three");
expected_functions.push_back("test_level_four");
for (const auto& found_function : found_functions) {
for (const auto& expected_function : expected_functions) {
if (found_function == expected_function) {
expected_functions.remove(found_function);
break;
}
}
}
ASSERT_TRUE(expected_functions.empty()) << "Not all functions found in shared library.";
}
static const char* CopySharedLibrary() {
#if defined(__LP64__)
const char* lib_name = "lib64";
#else
const char* lib_name = "lib";
#endif
#if defined(__BIONIC__)
const char* tmp_so_name = "/data/local/tmp/libbacktrace_test.so";
std::string cp_cmd = android::base::StringPrintf("cp /system/%s/libbacktrace_test.so %s",
lib_name, tmp_so_name);
#else
const char* tmp_so_name = "/tmp/libbacktrace_test.so";
if (getenv("ANDROID_HOST_OUT") == NULL) {
fprintf(stderr, "ANDROID_HOST_OUT not set, make sure you run lunch.");
return nullptr;
}
std::string cp_cmd = android::base::StringPrintf("cp %s/%s/libbacktrace_test.so %s",
getenv("ANDROID_HOST_OUT"), lib_name,
tmp_so_name);
#endif
// Copy the shared so to a tempory directory.
system(cp_cmd.c_str());
return tmp_so_name;
}
TEST(libbacktrace, check_unreadable_elf_local) {
const char* tmp_so_name = CopySharedLibrary();
ASSERT_TRUE(tmp_so_name != nullptr);
struct stat buf;
ASSERT_TRUE(stat(tmp_so_name, &buf) != -1);
uintptr_t map_size = buf.st_size;
int fd = open(tmp_so_name, O_RDONLY);
ASSERT_TRUE(fd != -1);
void* map = mmap(NULL, map_size, PROT_READ | PROT_EXEC, MAP_PRIVATE, fd, 0);
ASSERT_TRUE(map != MAP_FAILED);
close(fd);
ASSERT_TRUE(unlink(tmp_so_name) != -1);
std::vector<std::string> found_functions;
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(BACKTRACE_CURRENT_PROCESS,
BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace.get() != nullptr);
// Needed before GetFunctionName will work.
backtrace->Unwind(0);
// Loop through the entire map, and get every function we can find.
map_size += reinterpret_cast<uintptr_t>(map);
std::string last_func;
for (uintptr_t read_addr = reinterpret_cast<uintptr_t>(map);
read_addr < map_size; read_addr += 4) {
uintptr_t offset;
std::string func_name = backtrace->GetFunctionName(read_addr, &offset);
if (!func_name.empty() && last_func != func_name) {
found_functions.push_back(func_name);
}
last_func = func_name;
}
ASSERT_TRUE(munmap(map, map_size - reinterpret_cast<uintptr_t>(map)) == 0);
VerifyFunctionsFound(found_functions);
}
TEST(libbacktrace, check_unreadable_elf_remote) {
const char* tmp_so_name = CopySharedLibrary();
ASSERT_TRUE(tmp_so_name != nullptr);
g_ready = 0;
struct stat buf;
ASSERT_TRUE(stat(tmp_so_name, &buf) != -1);
uintptr_t map_size = buf.st_size;
pid_t pid;
if ((pid = fork()) == 0) {
int fd = open(tmp_so_name, O_RDONLY);
if (fd == -1) {
fprintf(stderr, "Failed to open file %s: %s\n", tmp_so_name, strerror(errno));
unlink(tmp_so_name);
exit(0);
}
void* map = mmap(NULL, map_size, PROT_READ | PROT_EXEC, MAP_PRIVATE, fd, 0);
if (map == MAP_FAILED) {
fprintf(stderr, "Failed to map in memory: %s\n", strerror(errno));
unlink(tmp_so_name);
exit(0);
}
close(fd);
if (unlink(tmp_so_name) == -1) {
fprintf(stderr, "Failed to unlink: %s\n", strerror(errno));
exit(0);
}
g_addr = reinterpret_cast<uintptr_t>(map);
g_ready = 1;
while (true) {
usleep(US_PER_MSEC);
}
exit(0);
}
ASSERT_TRUE(pid > 0);
std::vector<std::string> found_functions;
uint64_t start = NanoTime();
while (true) {
ASSERT_TRUE(ptrace(PTRACE_ATTACH, pid, 0, 0) == 0);
// Wait for the process to get to a stopping point.
WaitForStop(pid);
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace.get() != nullptr);
uintptr_t read_addr;
ASSERT_EQ(sizeof(uintptr_t), backtrace->Read(reinterpret_cast<uintptr_t>(&g_ready), reinterpret_cast<uint8_t*>(&read_addr), sizeof(uintptr_t)));
if (read_addr) {
ASSERT_EQ(sizeof(uintptr_t), backtrace->Read(reinterpret_cast<uintptr_t>(&g_addr), reinterpret_cast<uint8_t*>(&read_addr), sizeof(uintptr_t)));
// Needed before GetFunctionName will work.
backtrace->Unwind(0);
// Loop through the entire map, and get every function we can find.
map_size += read_addr;
std::string last_func;
for (; read_addr < map_size; read_addr += 4) {
uintptr_t offset;
std::string func_name = backtrace->GetFunctionName(read_addr, &offset);
if (!func_name.empty() && last_func != func_name) {
found_functions.push_back(func_name);
}
last_func = func_name;
}
break;
}
ASSERT_TRUE(ptrace(PTRACE_DETACH, pid, 0, 0) == 0);
if ((NanoTime() - start) > 5 * NS_PER_SEC) {
break;
}
usleep(US_PER_MSEC);
}
kill(pid, SIGKILL);
ASSERT_EQ(waitpid(pid, nullptr, 0), pid);
VerifyFunctionsFound(found_functions);
}
static bool FindFuncFrameInBacktrace(Backtrace* backtrace, uintptr_t test_func, size_t* frame_num) {
backtrace_map_t map;
backtrace->FillInMap(test_func, &map);
if (!BacktraceMap::IsValid(map)) {
return false;
}
// Loop through the frames, and find the one that is in the map.
*frame_num = 0;
for (Backtrace::const_iterator it = backtrace->begin(); it != backtrace->end(); ++it) {
if (BacktraceMap::IsValid(it->map) && map.start == it->map.start &&
it->pc >= test_func) {
*frame_num = it->num;
return true;
}
}
return false;
}
static void VerifyUnreadableElfFrame(Backtrace* backtrace, uintptr_t test_func, size_t frame_num) {
ASSERT_LT(backtrace->NumFrames(), static_cast<size_t>(MAX_BACKTRACE_FRAMES))
<< DumpFrames(backtrace);
ASSERT_TRUE(frame_num != 0) << DumpFrames(backtrace);
// Make sure that there is at least one more frame above the test func call.
ASSERT_LT(frame_num, backtrace->NumFrames()) << DumpFrames(backtrace);
uintptr_t diff = backtrace->GetFrame(frame_num)->pc - test_func;
ASSERT_LT(diff, 200U) << DumpFrames(backtrace);
}
static void VerifyUnreadableElfBacktrace(uintptr_t test_func) {
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(BACKTRACE_CURRENT_PROCESS,
BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
size_t frame_num;
ASSERT_TRUE(FindFuncFrameInBacktrace(backtrace.get(), test_func, &frame_num));
VerifyUnreadableElfFrame(backtrace.get(), test_func, frame_num);
}
typedef int (*test_func_t)(int, int, int, int, void (*)(uintptr_t), uintptr_t);
TEST(libbacktrace, unwind_through_unreadable_elf_local) {
const char* tmp_so_name = CopySharedLibrary();
ASSERT_TRUE(tmp_so_name != nullptr);
void* lib_handle = dlopen(tmp_so_name, RTLD_NOW);
ASSERT_TRUE(lib_handle != nullptr);
ASSERT_TRUE(unlink(tmp_so_name) != -1);
test_func_t test_func;
test_func = reinterpret_cast<test_func_t>(dlsym(lib_handle, "test_level_one"));
ASSERT_TRUE(test_func != nullptr);
ASSERT_NE(test_func(1, 2, 3, 4, VerifyUnreadableElfBacktrace,
reinterpret_cast<uintptr_t>(test_func)), 0);
ASSERT_TRUE(dlclose(lib_handle) == 0);
}
TEST(libbacktrace, unwind_through_unreadable_elf_remote) {
const char* tmp_so_name = CopySharedLibrary();
ASSERT_TRUE(tmp_so_name != nullptr);
void* lib_handle = dlopen(tmp_so_name, RTLD_NOW);
ASSERT_TRUE(lib_handle != nullptr);
ASSERT_TRUE(unlink(tmp_so_name) != -1);
test_func_t test_func;
test_func = reinterpret_cast<test_func_t>(dlsym(lib_handle, "test_level_one"));
ASSERT_TRUE(test_func != nullptr);
pid_t pid;
if ((pid = fork()) == 0) {
test_func(1, 2, 3, 4, 0, 0);
exit(0);
}
ASSERT_TRUE(pid > 0);
ASSERT_TRUE(dlclose(lib_handle) == 0);
uint64_t start = NanoTime();
bool done = false;
while (!done) {
ASSERT_TRUE(ptrace(PTRACE_ATTACH, pid, 0, 0) == 0);
// Wait for the process to get to a stopping point.
WaitForStop(pid);
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
size_t frame_num;
if (FindFuncFrameInBacktrace(backtrace.get(),
reinterpret_cast<uintptr_t>(test_func), &frame_num)) {
VerifyUnreadableElfFrame(backtrace.get(), reinterpret_cast<uintptr_t>(test_func), frame_num);
done = true;
}
ASSERT_TRUE(ptrace(PTRACE_DETACH, pid, 0, 0) == 0);
if ((NanoTime() - start) > 5 * NS_PER_SEC) {
break;
}
usleep(US_PER_MSEC);
}
kill(pid, SIGKILL);
ASSERT_EQ(waitpid(pid, nullptr, 0), pid);
ASSERT_TRUE(done) << "Test function never found in unwind.";
}
TEST(libbacktrace, unwind_thread_doesnt_exist) {
std::unique_ptr<Backtrace> backtrace(
Backtrace::Create(BACKTRACE_CURRENT_PROCESS, 99999999));
ASSERT_TRUE(backtrace.get() != nullptr);
ASSERT_FALSE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_ERROR_THREAD_DOESNT_EXIST, backtrace->GetError());
}
TEST(libbacktrace, local_get_function_name_before_unwind) {
std::unique_ptr<Backtrace> backtrace(
Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace.get() != nullptr);
// Verify that trying to get a function name before doing an unwind works.
uintptr_t cur_func_offset = reinterpret_cast<uintptr_t>(&test_level_one) + 1;
size_t offset;
ASSERT_NE(std::string(""), backtrace->GetFunctionName(cur_func_offset, &offset));
}
TEST(libbacktrace, remote_get_function_name_before_unwind) {
pid_t pid;
CreateRemoteProcess(&pid);
// Now create an unwind object.
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, pid));
// Verify that trying to get a function name before doing an unwind works.
uintptr_t cur_func_offset = reinterpret_cast<uintptr_t>(&test_level_one) + 1;
size_t offset;
ASSERT_NE(std::string(""), backtrace->GetFunctionName(cur_func_offset, &offset));
FinishRemoteProcess(pid);
}
static void SetUcontextSp(uintptr_t sp, ucontext_t* ucontext) {
#if defined(__arm__)
ucontext->uc_mcontext.arm_sp = sp;
#elif defined(__aarch64__)
ucontext->uc_mcontext.sp = sp;
#elif defined(__i386__)
ucontext->uc_mcontext.gregs[REG_ESP] = sp;
#elif defined(__x86_64__)
ucontext->uc_mcontext.gregs[REG_RSP] = sp;
#else
UNUSED(sp);
UNUSED(ucontext);
ASSERT_TRUE(false) << "Unsupported architecture";
#endif
}
static void SetUcontextPc(uintptr_t pc, ucontext_t* ucontext) {
#if defined(__arm__)
ucontext->uc_mcontext.arm_pc = pc;
#elif defined(__aarch64__)
ucontext->uc_mcontext.pc = pc;
#elif defined(__i386__)
ucontext->uc_mcontext.gregs[REG_EIP] = pc;
#elif defined(__x86_64__)
ucontext->uc_mcontext.gregs[REG_RIP] = pc;
#else
UNUSED(pc);
UNUSED(ucontext);
ASSERT_TRUE(false) << "Unsupported architecture";
#endif
}
static void SetUcontextLr(uintptr_t lr, ucontext_t* ucontext) {
#if defined(__arm__)
ucontext->uc_mcontext.arm_lr = lr;
#elif defined(__aarch64__)
ucontext->uc_mcontext.regs[30] = lr;
#elif defined(__i386__)
// The lr is on the stack.
ASSERT_TRUE(lr != 0);
ASSERT_TRUE(ucontext != nullptr);
#elif defined(__x86_64__)
// The lr is on the stack.
ASSERT_TRUE(lr != 0);
ASSERT_TRUE(ucontext != nullptr);
#else
UNUSED(lr);
UNUSED(ucontext);
ASSERT_TRUE(false) << "Unsupported architecture";
#endif
}
static constexpr size_t DEVICE_MAP_SIZE = 1024;
static void SetupDeviceMap(void** device_map) {
// Make sure that anything in a device map will result in fails
// to read.
android::base::unique_fd device_fd(open("/dev/zero", O_RDONLY | O_CLOEXEC));
*device_map = mmap(nullptr, 1024, PROT_READ, MAP_PRIVATE, device_fd, 0);
ASSERT_TRUE(*device_map != MAP_FAILED);
// Make sure the map is readable.
ASSERT_EQ(0, reinterpret_cast<int*>(*device_map)[0]);
}
static void UnwindFromDevice(Backtrace* backtrace, void* device_map) {
uintptr_t device_map_uint = reinterpret_cast<uintptr_t>(device_map);
backtrace_map_t map;
backtrace->FillInMap(device_map_uint, &map);
// Verify the flag is set.
ASSERT_EQ(PROT_DEVICE_MAP, map.flags & PROT_DEVICE_MAP);
// Quick sanity checks.
size_t offset;
ASSERT_EQ(std::string(""), backtrace->GetFunctionName(device_map_uint, &offset));
ASSERT_EQ(std::string(""), backtrace->GetFunctionName(device_map_uint, &offset, &map));
ASSERT_EQ(std::string(""), backtrace->GetFunctionName(0, &offset));
uintptr_t cur_func_offset = reinterpret_cast<uintptr_t>(&test_level_one) + 1;
// Now verify the device map flag actually causes the function name to be empty.
backtrace->FillInMap(cur_func_offset, &map);
ASSERT_TRUE((map.flags & PROT_DEVICE_MAP) == 0);
ASSERT_NE(std::string(""), backtrace->GetFunctionName(cur_func_offset, &offset, &map));
map.flags |= PROT_DEVICE_MAP;
ASSERT_EQ(std::string(""), backtrace->GetFunctionName(cur_func_offset, &offset, &map));
ucontext_t ucontext;
// Create a context that has the pc in the device map, but the sp
// in a non-device map.
memset(&ucontext, 0, sizeof(ucontext));
SetUcontextSp(reinterpret_cast<uintptr_t>(&ucontext), &ucontext);
SetUcontextPc(device_map_uint, &ucontext);
SetUcontextLr(cur_func_offset, &ucontext);
ASSERT_TRUE(backtrace->Unwind(0, &ucontext));
// The buffer should only be a single element.
ASSERT_EQ(1U, backtrace->NumFrames());
const backtrace_frame_data_t* frame = backtrace->GetFrame(0);
ASSERT_EQ(device_map_uint, frame->pc);
ASSERT_EQ(reinterpret_cast<uintptr_t>(&ucontext), frame->sp);
// Check what happens when skipping the first frame.
ASSERT_TRUE(backtrace->Unwind(1, &ucontext));
ASSERT_EQ(0U, backtrace->NumFrames());
// Create a context that has the sp in the device map, but the pc
// in a non-device map.
memset(&ucontext, 0, sizeof(ucontext));
SetUcontextSp(device_map_uint, &ucontext);
SetUcontextPc(cur_func_offset, &ucontext);
SetUcontextLr(cur_func_offset, &ucontext);
ASSERT_TRUE(backtrace->Unwind(0, &ucontext));
// The buffer should only be a single element.
ASSERT_EQ(1U, backtrace->NumFrames());
frame = backtrace->GetFrame(0);
ASSERT_EQ(cur_func_offset, frame->pc);
ASSERT_EQ(device_map_uint, frame->sp);
// Check what happens when skipping the first frame.
ASSERT_TRUE(backtrace->Unwind(1, &ucontext));
ASSERT_EQ(0U, backtrace->NumFrames());
}
TEST(libbacktrace, unwind_disallow_device_map_local) {
void* device_map;
SetupDeviceMap(&device_map);
// Now create an unwind object.
std::unique_ptr<Backtrace> backtrace(
Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
ASSERT_TRUE(backtrace);
UnwindFromDevice(backtrace.get(), device_map);
munmap(device_map, DEVICE_MAP_SIZE);
}
TEST(libbacktrace, unwind_disallow_device_map_remote) {
void* device_map;
SetupDeviceMap(&device_map);
// Fork a process to do a remote backtrace.
pid_t pid;
CreateRemoteProcess(&pid);
// Now create an unwind object.
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, pid));
// TODO: Currently unwind from context doesn't work on remote
// unwind. Keep this test because the new unwinder should support
// this eventually, or we can delete this test.
// properly with unwind from context.
// UnwindFromDevice(backtrace.get(), device_map);
FinishRemoteProcess(pid);
munmap(device_map, DEVICE_MAP_SIZE);
}
class ScopedSignalHandler {
public:
ScopedSignalHandler(int signal_number, void (*handler)(int)) : signal_number_(signal_number) {
memset(&action_, 0, sizeof(action_));
action_.sa_handler = handler;
sigaction(signal_number_, &action_, &old_action_);
}
ScopedSignalHandler(int signal_number, void (*action)(int, siginfo_t*, void*))
: signal_number_(signal_number) {
memset(&action_, 0, sizeof(action_));
action_.sa_flags = SA_SIGINFO;
action_.sa_sigaction = action;
sigaction(signal_number_, &action_, &old_action_);
}
~ScopedSignalHandler() { sigaction(signal_number_, &old_action_, nullptr); }
private:
struct sigaction action_;
struct sigaction old_action_;
const int signal_number_;
};
static void SetValueAndLoop(void* data) {
volatile int* value = reinterpret_cast<volatile int*>(data);
*value = 1;
for (volatile int i = 0;; i++)
;
}
static void UnwindThroughSignal(bool use_action) {
volatile int value = 0;
pid_t pid;
if ((pid = fork()) == 0) {
if (use_action) {
ScopedSignalHandler ssh(SIGUSR1, test_signal_action);
test_level_one(1, 2, 3, 4, SetValueAndLoop, const_cast<int*>(&value));
} else {
ScopedSignalHandler ssh(SIGUSR1, test_signal_handler);
test_level_one(1, 2, 3, 4, SetValueAndLoop, const_cast<int*>(&value));
}
}
ASSERT_NE(-1, pid);
int read_value = 0;
uint64_t start = NanoTime();
while (read_value == 0) {
usleep(1000);
// Loop until the remote function gets into the final function.
ASSERT_TRUE(ptrace(PTRACE_ATTACH, pid, 0, 0) == 0);
WaitForStop(pid);
std::unique_ptr<Backtrace> backtrace(Backtrace::Create(pid, pid));
size_t bytes_read = backtrace->Read(reinterpret_cast<uintptr_t>(const_cast<int*>(&value)),
reinterpret_cast<uint8_t*>(&read_value), sizeof(read_value));
ASSERT_EQ(sizeof(read_value), bytes_read);
ASSERT_TRUE(ptrace(PTRACE_DETACH, pid, 0, 0) == 0);
ASSERT_TRUE(NanoTime() - start < 5 * NS_PER_SEC)
<< "Remote process did not execute far enough in 5 seconds.";
}
// Now need to send a signal to the remote process.
kill(pid, SIGUSR1);
// Wait for the process to get to the signal handler loop.
Backtrace::const_iterator frame_iter;
start = NanoTime();
std::unique_ptr<Backtrace> backtrace;
while (true) {
usleep(1000);
ASSERT_TRUE(ptrace(PTRACE_ATTACH, pid, 0, 0) == 0);
WaitForStop(pid);
backtrace.reset(Backtrace::Create(pid, pid));
ASSERT_TRUE(backtrace->Unwind(0));
bool found = false;
for (frame_iter = backtrace->begin(); frame_iter != backtrace->end(); ++frame_iter) {
if (frame_iter->func_name == "test_loop_forever") {
++frame_iter;
found = true;
break;
}
}
if (found) {
break;
}
ASSERT_TRUE(ptrace(PTRACE_DETACH, pid, 0, 0) == 0);
ASSERT_TRUE(NanoTime() - start < 5 * NS_PER_SEC)
<< "Remote process did not get in signal handler in 5 seconds." << std::endl
<< DumpFrames(backtrace.get());
}
std::vector<std::string> names;
// Loop through the frames, and save the function names.
size_t frame = 0;
for (; frame_iter != backtrace->end(); ++frame_iter) {
if (frame_iter->func_name == "test_level_four") {
frame = names.size() + 1;
}
names.push_back(frame_iter->func_name);
}
ASSERT_NE(0U, frame) << "Unable to find test_level_four in backtrace" << std::endl
<< DumpFrames(backtrace.get());
// The expected order of the frames:
// test_loop_forever
// test_signal_handler|test_signal_action
// <OPTIONAL_FRAME> May or may not exist.
// SetValueAndLoop (but the function name might be empty)
// test_level_four
// test_level_three
// test_level_two
// test_level_one
ASSERT_LE(frame + 2, names.size()) << DumpFrames(backtrace.get());
ASSERT_LE(2U, frame) << DumpFrames(backtrace.get());
if (use_action) {
ASSERT_EQ("test_signal_action", names[0]) << DumpFrames(backtrace.get());
} else {
ASSERT_EQ("test_signal_handler", names[0]) << DumpFrames(backtrace.get());
}
ASSERT_EQ("test_level_three", names[frame]) << DumpFrames(backtrace.get());
ASSERT_EQ("test_level_two", names[frame + 1]) << DumpFrames(backtrace.get());
ASSERT_EQ("test_level_one", names[frame + 2]) << DumpFrames(backtrace.get());
FinishRemoteProcess(pid);
}
TEST(libbacktrace, unwind_remote_through_signal_using_handler) { UnwindThroughSignal(false); }
TEST(libbacktrace, unwind_remote_through_signal_using_action) { UnwindThroughSignal(true); }
#if defined(ENABLE_PSS_TESTS)
#include "GetPss.h"
#define MAX_LEAK_BYTES (32*1024UL)
static void CheckForLeak(pid_t pid, pid_t tid) {
// Do a few runs to get the PSS stable.
for (size_t i = 0; i < 100; i++) {
Backtrace* backtrace = Backtrace::Create(pid, tid);
ASSERT_TRUE(backtrace != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
delete backtrace;
}
size_t stable_pss = GetPssBytes();
ASSERT_TRUE(stable_pss != 0);
// Loop enough that even a small leak should be detectable.
for (size_t i = 0; i < 4096; i++) {
Backtrace* backtrace = Backtrace::Create(pid, tid);
ASSERT_TRUE(backtrace != nullptr);
ASSERT_TRUE(backtrace->Unwind(0));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, backtrace->GetError());
delete backtrace;
}
size_t new_pss = GetPssBytes();
ASSERT_TRUE(new_pss != 0);
if (new_pss > stable_pss) {
ASSERT_LE(new_pss - stable_pss, MAX_LEAK_BYTES);
}
}
TEST(libbacktrace, check_for_leak_local) {
CheckForLeak(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD);
}
TEST(libbacktrace, check_for_leak_local_thread) {
thread_t thread_data = { 0, 0, 0, nullptr };
pthread_t thread;
ASSERT_TRUE(pthread_create(&thread, nullptr, ThreadLevelRun, &thread_data) == 0);
// Wait up to 2 seconds for the tid to be set.
ASSERT_TRUE(WaitForNonZero(&thread_data.state, 2));
CheckForLeak(BACKTRACE_CURRENT_PROCESS, thread_data.tid);
// Tell the thread to exit its infinite loop.
android_atomic_acquire_store(0, &thread_data.state);
ASSERT_TRUE(pthread_join(thread, nullptr) == 0);
}
TEST(libbacktrace, check_for_leak_remote) {
pid_t pid;
CreateRemoteProcess(&pid);
CheckForLeak(pid, BACKTRACE_CURRENT_THREAD);
FinishRemoteProcess(pid);
}
#endif
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