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/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <errno.h>
#include <signal.h>
#include <stdint.h>
#include <string.h>
#include <sys/ptrace.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <gtest/gtest.h>
#include <atomic>
#include <memory>
#include <sstream>
#include <string>
#include <thread>
#include <vector>
#include <android-base/stringprintf.h>
#include <unwindstack/Maps.h>
#include <unwindstack/Memory.h>
#include <unwindstack/Regs.h>
#include <unwindstack/RegsGetLocal.h>
#include <unwindstack/Unwinder.h>
#include "TestUtils.h"
namespace unwindstack {
static std::atomic_bool g_ready;
static volatile bool g_ready_for_remote;
static volatile bool g_signal_ready_for_remote;
static std::atomic_bool g_finish;
static std::atomic_uintptr_t g_ucontext;
static void ResetGlobals() {
g_ready = false;
g_ready_for_remote = false;
g_signal_ready_for_remote = false;
g_finish = false;
g_ucontext = 0;
}
static std::vector<const char*> kFunctionOrder{"OuterFunction", "MiddleFunction", "InnerFunction"};
static std::vector<const char*> kFunctionSignalOrder{"OuterFunction", "MiddleFunction",
"InnerFunction", "SignalOuterFunction",
"SignalMiddleFunction", "SignalInnerFunction"};
static void SignalHandler(int, siginfo_t*, void* sigcontext) {
g_ucontext = reinterpret_cast<uintptr_t>(sigcontext);
while (!g_finish.load()) {
}
}
extern "C" void SignalInnerFunction() {
g_signal_ready_for_remote = true;
while (!g_finish.load()) {
}
}
extern "C" void SignalMiddleFunction() {
SignalInnerFunction();
}
extern "C" void SignalOuterFunction() {
SignalMiddleFunction();
}
static void SignalCallerHandler(int, siginfo_t*, void*) {
SignalOuterFunction();
}
static std::string ErrorMsg(const std::vector<const char*>& function_names, Unwinder& unwinder) {
std::string unwind;
for (size_t i = 0; i < unwinder.NumFrames(); i++) {
unwind += unwinder.FormatFrame(i) + '\n';
}
return std::string(
"Unwind completed without finding all frames\n"
" Looking for function: ") +
function_names.front() + "\n" + "Unwind data:\n" + unwind;
}
static void VerifyUnwind(pid_t pid, Maps* maps, Regs* regs,
std::vector<const char*> expected_function_names) {
auto process_memory(Memory::CreateProcessMemory(pid));
Unwinder unwinder(512, maps, regs, process_memory);
unwinder.Unwind();
std::string expected_function = expected_function_names.back();
expected_function_names.pop_back();
for (auto& frame : unwinder.frames()) {
if (frame.function_name == expected_function) {
if (expected_function_names.empty()) {
break;
}
expected_function = expected_function_names.back();
expected_function_names.pop_back();
}
}
ASSERT_TRUE(expected_function_names.empty()) << ErrorMsg(expected_function_names, unwinder);
}
// This test assumes that this code is compiled with optimizations turned
// off. If this doesn't happen, then all of the calls will be optimized
// away.
extern "C" void InnerFunction(bool local, bool trigger_invalid_call) {
if (local) {
LocalMaps maps;
ASSERT_TRUE(maps.Parse());
std::unique_ptr<Regs> regs(Regs::CreateFromLocal());
RegsGetLocal(regs.get());
VerifyUnwind(getpid(), &maps, regs.get(), kFunctionOrder);
} else {
g_ready_for_remote = true;
g_ready = true;
if (trigger_invalid_call) {
void (*crash_func)() = nullptr;
crash_func();
}
while (!g_finish.load()) {
}
}
}
extern "C" void MiddleFunction(bool local, bool trigger_invalid_call) {
InnerFunction(local, trigger_invalid_call);
}
extern "C" void OuterFunction(bool local, bool trigger_invalid_call) {
MiddleFunction(local, trigger_invalid_call);
}
class UnwindTest : public ::testing::Test {
public:
void SetUp() override { ResetGlobals(); }
};
TEST_F(UnwindTest, local) {
OuterFunction(true, false);
}
void WaitForRemote(pid_t pid, uint64_t addr, bool leave_attached, bool* completed) {
*completed = false;
// Need to sleep before attempting first ptrace. Without this, on the
// host it becomes impossible to attach and ptrace sets errno to EPERM.
usleep(1000);
for (size_t i = 0; i < 1000; i++) {
if (ptrace(PTRACE_ATTACH, pid, 0, 0) == 0) {
ASSERT_TRUE(TestQuiescePid(pid))
<< "Waiting for process to quiesce failed: " << strerror(errno);
MemoryRemote memory(pid);
// Read the remote value to see if we are ready.
bool value;
if (memory.ReadFully(addr, &value, sizeof(value)) && value) {
*completed = true;
}
if (!*completed || !leave_attached) {
ASSERT_EQ(0, ptrace(PTRACE_DETACH, pid, 0, 0));
}
if (*completed) {
break;
}
} else {
ASSERT_EQ(ESRCH, errno) << "ptrace attach failed with unexpected error: " << strerror(errno);
}
usleep(5000);
}
}
TEST_F(UnwindTest, remote) {
pid_t pid;
if ((pid = fork()) == 0) {
OuterFunction(false, false);
exit(0);
}
ASSERT_NE(-1, pid);
TestScopedPidReaper reap(pid);
bool completed;
WaitForRemote(pid, reinterpret_cast<uint64_t>(&g_ready_for_remote), true, &completed);
ASSERT_TRUE(completed) << "Timed out waiting for remote process to be ready.";
RemoteMaps maps(pid);
ASSERT_TRUE(maps.Parse());
std::unique_ptr<Regs> regs(Regs::RemoteGet(pid));
ASSERT_TRUE(regs.get() != nullptr);
VerifyUnwind(pid, &maps, regs.get(), kFunctionOrder);
ASSERT_EQ(0, ptrace(PTRACE_DETACH, pid, 0, 0))
<< "ptrace detach failed with unexpected error: " << strerror(errno);
}
TEST_F(UnwindTest, from_context) {
std::atomic_int tid(0);
std::thread thread([&]() {
tid = syscall(__NR_gettid);
OuterFunction(false, false);
});
struct sigaction act, oldact;
memset(&act, 0, sizeof(act));
act.sa_sigaction = SignalHandler;
act.sa_flags = SA_RESTART | SA_SIGINFO | SA_ONSTACK;
ASSERT_EQ(0, sigaction(SIGUSR1, &act, &oldact));
// Wait for the tid to get set.
for (size_t i = 0; i < 100; i++) {
if (tid.load() != 0) {
break;
}
usleep(1000);
}
ASSERT_NE(0, tid.load());
// Portable tgkill method.
ASSERT_EQ(0, syscall(__NR_tgkill, getpid(), tid.load(), SIGUSR1)) << "Error: " << strerror(errno);
// Wait for context data.
void* ucontext;
for (size_t i = 0; i < 2000; i++) {
ucontext = reinterpret_cast<void*>(g_ucontext.load());
if (ucontext != nullptr) {
break;
}
usleep(1000);
}
ASSERT_TRUE(ucontext != nullptr) << "Timed out waiting for thread to respond to signal.";
LocalMaps maps;
ASSERT_TRUE(maps.Parse());
std::unique_ptr<Regs> regs(Regs::CreateFromUcontext(Regs::CurrentArch(), ucontext));
VerifyUnwind(getpid(), &maps, regs.get(), kFunctionOrder);
ASSERT_EQ(0, sigaction(SIGUSR1, &oldact, nullptr));
g_finish = true;
thread.join();
}
static void RemoteThroughSignal(int signal, unsigned int sa_flags) {
pid_t pid;
if ((pid = fork()) == 0) {
struct sigaction act, oldact;
memset(&act, 0, sizeof(act));
act.sa_sigaction = SignalCallerHandler;
act.sa_flags = SA_RESTART | SA_ONSTACK | sa_flags;
ASSERT_EQ(0, sigaction(signal, &act, &oldact));
OuterFunction(false, signal == SIGSEGV);
exit(0);
}
ASSERT_NE(-1, pid);
TestScopedPidReaper reap(pid);
bool completed;
if (signal != SIGSEGV) {
WaitForRemote(pid, reinterpret_cast<uint64_t>(&g_ready_for_remote), false, &completed);
ASSERT_TRUE(completed) << "Timed out waiting for remote process to be ready.";
ASSERT_EQ(0, kill(pid, SIGUSR1));
}
WaitForRemote(pid, reinterpret_cast<uint64_t>(&g_signal_ready_for_remote), true, &completed);
ASSERT_TRUE(completed) << "Timed out waiting for remote process to be in signal handler.";
RemoteMaps maps(pid);
ASSERT_TRUE(maps.Parse());
std::unique_ptr<Regs> regs(Regs::RemoteGet(pid));
ASSERT_TRUE(regs.get() != nullptr);
VerifyUnwind(pid, &maps, regs.get(), kFunctionSignalOrder);
ASSERT_EQ(0, ptrace(PTRACE_DETACH, pid, 0, 0))
<< "ptrace detach failed with unexpected error: " << strerror(errno);
}
TEST_F(UnwindTest, remote_through_signal) {
RemoteThroughSignal(SIGUSR1, 0);
}
TEST_F(UnwindTest, remote_through_signal_sa_siginfo) {
RemoteThroughSignal(SIGUSR1, SA_SIGINFO);
}
TEST_F(UnwindTest, remote_through_signal_with_invalid_func) {
RemoteThroughSignal(SIGSEGV, 0);
}
TEST_F(UnwindTest, remote_through_signal_sa_siginfo_with_invalid_func) {
RemoteThroughSignal(SIGSEGV, SA_SIGINFO);
}
// Verify that using the same map while unwinding multiple threads at the
// same time doesn't cause problems.
TEST_F(UnwindTest, multiple_threads_unwind_same_map) {
static constexpr size_t kNumConcurrentThreads = 100;
LocalMaps maps;
ASSERT_TRUE(maps.Parse());
auto process_memory(Memory::CreateProcessMemory(getpid()));
std::vector<std::thread*> threads;
std::atomic_bool wait;
wait = true;
size_t frames[kNumConcurrentThreads];
for (size_t i = 0; i < kNumConcurrentThreads; i++) {
std::thread* thread = new std::thread([i, &frames, &maps, &process_memory, &wait]() {
while (wait)
;
std::unique_ptr<Regs> regs(Regs::CreateFromLocal());
RegsGetLocal(regs.get());
Unwinder unwinder(512, &maps, regs.get(), process_memory);
unwinder.Unwind();
frames[i] = unwinder.NumFrames();
ASSERT_LE(3U, frames[i]) << "Failed for thread " << i;
});
threads.push_back(thread);
}
wait = false;
for (auto thread : threads) {
thread->join();
delete thread;
}
}
} // namespace unwindstack