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platform_system_core/libbacktrace/backtrace_test.cpp
Christopher Ferris b7de5f5429 Demand read load bias for a map. 
Add a static GetLoadBias method to the Elf object that only reads just
enough to get the load bias.

Add a method to MapInfo that gets the load bias. First attempt to get
it if the elf object already exists. If no elf object was created, use
the new static method to get the load bias.

In BacktraceMap, add a custom iterator so that when code dereferences
a map element, that's when the load bias will be retrieved if it hasn't
already been set.

Bug: 69871050

Test: New unit tests, verify tombstones have non-zero load bias values for
Test: libraries with a non-zero load bias.
Change-Id: I125f4abc827589957fce2f0df24b0f25d037d732
2017-12-05 13:12:47 -08:00

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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;
BacktraceMap* map;
Backtrace* backtrace;
int32_t* now;
int32_t done;
};
typedef Backtrace* (*create_func_t)(pid_t, pid_t, BacktraceMap*);
typedef BacktraceMap* (*map_create_func_t)(pid_t, bool);
static void VerifyLevelDump(Backtrace* backtrace, create_func_t create_func = nullptr,
map_create_func_t map_func = nullptr);
static void VerifyMaxDump(Backtrace* backtrace, create_func_t create_func = nullptr,
map_create_func_t map_func = nullptr);
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, create_func_t, map_create_func_t) {
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, create_func_t, map_create_func_t) {
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) {
ASSERT_EQ(bt_all->NumFrames(), bt_ign1->NumFrames() + 1) << "All backtrace:\n"
<< DumpFrames(bt_all)
<< "Ignore 1 backtrace:\n"
<< DumpFrames(bt_ign1);
ASSERT_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 (*ReadyFunc)(Backtrace*),
void (*VerifyFunc)(Backtrace*, create_func_t, map_create_func_t),
create_func_t create_func, map_create_func_t map_create_func) {
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;
map.reset(map_create_func(pid, false));
std::unique_ptr<Backtrace> backtrace(create_func(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(), create_func, map_create_func);
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, ReadyLevelBacktrace, VerifyLevelDump,
Backtrace::Create, BacktraceMap::Create);
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, ReadyMaxBacktrace, VerifyMaxDump, Backtrace::Create,
BacktraceMap::Create);
kill(pid, SIGKILL);
int status;
ASSERT_EQ(waitpid(pid, &status, 0), pid);
}
static void VerifyProcessIgnoreFrames(Backtrace* bt_all, create_func_t create_func,
map_create_func_t map_create_func) {
std::unique_ptr<BacktraceMap> map(map_create_func(bt_all->Pid(), false));
std::unique_ptr<Backtrace> ign1(create_func(bt_all->Pid(), BACKTRACE_CURRENT_THREAD, map.get()));
ASSERT_TRUE(ign1.get() != nullptr);
ASSERT_TRUE(ign1->Unwind(1));
ASSERT_EQ(BACKTRACE_UNWIND_NO_ERROR, ign1->GetError());
std::unique_ptr<Backtrace> ign2(create_func(bt_all->Pid(), BACKTRACE_CURRENT_THREAD, map.get()));
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, ReadyLevelBacktrace, VerifyProcessIgnoreFrames,
Backtrace::Create, BacktraceMap::Create);
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, ReadyLevelBacktrace, VerifyLevelDump, Backtrace::Create,
BacktraceMap::Create);
}
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->map);
dump->backtrace->Unwind(0);
android_atomic_acquire_store(1, &dump->done);
return nullptr;
}
static void MultipleThreadDumpTest(bool share_map) {
// Dump NUM_THREADS simultaneously using the same map.
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.
std::unique_ptr<BacktraceMap> map;
if (share_map) {
map.reset(BacktraceMap::Create(getpid()));
}
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;
dumpers[i].map = map.get();
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) {
MultipleThreadDumpTest(false);
}
TEST(libbacktrace, thread_multiple_dump_same_map) {
MultipleThreadDumpTest(true);
}
// 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.rel_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.rel_pc = 0x20;
frame.map.start = 0xb0000;
frame.map.end = 0xbffff;
frame.map.load_bias = 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_bias = 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.rel_pc = 0x12345678;
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_bias is non-zero.
frame.rel_pc = 0x123456dc;
frame.func_offset = 645;
frame.map.load_bias = 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 std::string GetTestMapsAsString(const std::vector<map_test_t>& maps) {
if (maps.size() == 0) {
return "No test map entries\n";
}
std::string map_txt;
for (auto map : maps) {
map_txt += android::base::StringPrintf("%" PRIxPTR "-%" PRIxPTR "\n", map.start, map.end);
}
return map_txt;
}
static std::string GetMapsAsString(BacktraceMap* maps) {
if (maps->size() == 0) {
return "No map entries\n";
}
std::string map_txt;
for (const backtrace_map_t* map : *maps) {
map_txt += android::base::StringPrintf(
"%" PRIxPTR "-%" PRIxPTR " flags: 0x%x offset: 0x%" PRIxPTR " load_bias: 0x%" PRIxPTR,
map->start, map->end, map->flags, map->offset, map->load_bias);
if (!map->name.empty()) {
map_txt += ' ' + map->name;
}
map_txt += '\n';
}
return map_txt;
}
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.
auto test_it = test_maps.begin();
for (auto it = map->begin(); it != map->end(); ++it) {
ASSERT_TRUE(test_it != test_maps.end()) << "Mismatch in number of maps, expected test maps:\n"
<< GetTestMapsAsString(test_maps) << "Actual maps:\n"
<< GetMapsAsString(map.get());
ASSERT_EQ(test_it->start, (*it)->start) << "Mismatch in map data, expected test maps:\n"
<< GetTestMapsAsString(test_maps) << "Actual maps:\n"
<< GetMapsAsString(map.get());
ASSERT_EQ(test_it->end, (*it)->end) << "Mismatch maps in map data, expected test maps:\n"
<< GetTestMapsAsString(test_maps) << "Actual maps:\n"
<< GetMapsAsString(map.get());
// Make sure the load bias get set to a value.
ASSERT_NE(static_cast<uint64_t>(-1), (*it)->load_bias) << "Found uninitialized load_bias\n"
<< GetMapsAsString(map.get());
++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));
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, create_func_t create_func,
map_create_func_t map_create_func) {
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<BacktraceMap> map(map_create_func(pid, false));
std::unique_ptr<Backtrace> backtrace(create_func(pid, pid, map.get()));
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<BacktraceMap> map;
std::unique_ptr<Backtrace> backtrace;
while (true) {
usleep(1000);
ASSERT_TRUE(ptrace(PTRACE_ATTACH, pid, 0, 0) == 0);
WaitForStop(pid);
map.reset(map_create_func(pid, false));
ASSERT_TRUE(map.get() != nullptr);
backtrace.reset(create_func(pid, pid, map.get()));
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, Backtrace::Create, BacktraceMap::Create);
}
TEST(libbacktrace, unwind_remote_through_signal_using_action) {
UnwindThroughSignal(true, Backtrace::Create, BacktraceMap::Create);
}
static void TestFrameSkipNumbering(create_func_t create_func, map_create_func_t map_create_func) {
std::unique_ptr<BacktraceMap> map(map_create_func(getpid(), false));
std::unique_ptr<Backtrace> backtrace(create_func(getpid(), gettid(), map.get()));
backtrace->Unwind(1);
ASSERT_NE(0U, backtrace->NumFrames());
ASSERT_EQ(0U, backtrace->GetFrame(0)->num);
}
TEST(libbacktrace, unwind_frame_skip_numbering) {
TestFrameSkipNumbering(Backtrace::Create, BacktraceMap::Create);
}
#if defined(ENABLE_PSS_TESTS)
#include "GetPss.h"
#define MAX_LEAK_BYTES (32*1024UL)
static void CheckForLeak(pid_t pid, pid_t tid) {
std::unique_ptr<BacktraceMap> map(BacktraceMap::Create(pid));
// Do a few runs to get the PSS stable.
for (size_t i = 0; i < 100; i++) {
Backtrace* backtrace = Backtrace::Create(pid, tid, map.get());
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, map.get());
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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