libunwindstack/tests/UnwindTest.cpp - android_system_core - Gitiles

 /*
  * 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 <android-base/threads.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 {

 enum TestTypeEnum : uint8_t {
   TEST_TYPE_LOCAL_UNWINDER = 0,
   TEST_TYPE_LOCAL_UNWINDER_FROM_PID,
   TEST_TYPE_LOCAL_WAIT_FOR_FINISH,
   TEST_TYPE_REMOTE,
   TEST_TYPE_REMOTE_WITH_INVALID_CALL,
 };

 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;
   // Avoid any function calls because not every instruction will be
   // unwindable.
   // This method of looping is only used when testing a remote unwind.
   while (true) {
   }
 }

 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(Unwinder* unwinder, std::vector<const char*> expected_function_names) {
   unwinder->Unwind();

   for (auto& frame : unwinder->frames()) {
     if (frame.function_name == expected_function_names.back()) {
       expected_function_names.pop_back();
       if (expected_function_names.empty()) {
         break;
       }
     }
   }

   ASSERT_TRUE(expected_function_names.empty()) << ErrorMsg(expected_function_names, unwinder);
 }

 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);
   VerifyUnwind(&unwinder, expected_function_names);
 }

 // 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(TestTypeEnum test_type) {
   if (test_type == TEST_TYPE_LOCAL_WAIT_FOR_FINISH) {
     while (!g_finish.load()) {
     }
     return;
   }
   if (test_type == TEST_TYPE_REMOTE || test_type == TEST_TYPE_REMOTE_WITH_INVALID_CALL) {
     g_ready_for_remote = true;
     g_ready = true;
     if (test_type == TEST_TYPE_REMOTE_WITH_INVALID_CALL) {
       void (*crash_func)() = nullptr;
       crash_func();
     }
     // Avoid any function calls because not every instruction will be
     // unwindable.
     // This method of looping is only used when testing a remote unwind.
     while (true) {
     }
     return;
   }

   std::unique_ptr<Unwinder> unwinder;
   std::unique_ptr<Regs> regs(Regs::CreateFromLocal());
   RegsGetLocal(regs.get());
   std::unique_ptr<Maps> maps;

   if (test_type == TEST_TYPE_LOCAL_UNWINDER) {
     maps.reset(new LocalMaps());
     ASSERT_TRUE(maps->Parse());
     auto process_memory(Memory::CreateProcessMemory(getpid()));
     unwinder.reset(new Unwinder(512, maps.get(), regs.get(), process_memory));
   } else {
     UnwinderFromPid* unwinder_from_pid = new UnwinderFromPid(512, getpid());
     ASSERT_TRUE(unwinder_from_pid->Init(regs->Arch()));
     unwinder_from_pid->SetRegs(regs.get());
     unwinder.reset(unwinder_from_pid);
   }
   VerifyUnwind(unwinder.get(), kFunctionOrder);
 }

 extern "C" void MiddleFunction(TestTypeEnum test_type) {
   InnerFunction(test_type);
 }

 extern "C" void OuterFunction(TestTypeEnum test_type) {
   MiddleFunction(test_type);
 }

 class UnwindTest : public ::testing::Test {
  public:
   void SetUp() override { ResetGlobals(); }
 };

 TEST_F(UnwindTest, local) {
   OuterFunction(TEST_TYPE_LOCAL_UNWINDER);
 }

 TEST_F(UnwindTest, local_use_from_pid) {
   OuterFunction(TEST_TYPE_LOCAL_UNWINDER_FROM_PID);
 }

 static void LocalUnwind(void* data) {
   TestTypeEnum* test_type = reinterpret_cast<TestTypeEnum*>(data);
   OuterFunction(*test_type);
 }

 TEST_F(UnwindTest, local_check_for_leak) {
   TestTypeEnum test_type = TEST_TYPE_LOCAL_UNWINDER;
   TestCheckForLeaks(LocalUnwind, &test_type);
 }

 TEST_F(UnwindTest, local_use_from_pid_check_for_leak) {
   TestTypeEnum test_type = TEST_TYPE_LOCAL_UNWINDER_FROM_PID;
   TestCheckForLeaks(LocalUnwind, &test_type);
 }

 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(TEST_TYPE_REMOTE);
     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, unwind_from_pid_remote) {
   pid_t pid;
   if ((pid = fork()) == 0) {
     OuterFunction(TEST_TYPE_REMOTE);
     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.";

   std::unique_ptr<Regs> regs(Regs::RemoteGet(pid));
   ASSERT_TRUE(regs.get() != nullptr);

   UnwinderFromPid unwinder(512, pid);
   ASSERT_TRUE(unwinder.Init(regs->Arch()));
   unwinder.SetRegs(regs.get());

   VerifyUnwind(&unwinder, kFunctionOrder);

   // Verify that calling the same object works again.

   ASSERT_EQ(0, ptrace(PTRACE_DETACH, pid, 0, 0))
       << "ptrace detach failed with unexpected error: " << strerror(errno);
 }

 static void RemoteCheckForLeaks(void (*unwind_func)(void*)) {
   pid_t pid;
   if ((pid = fork()) == 0) {
     OuterFunction(TEST_TYPE_REMOTE);
     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.";

   TestCheckForLeaks(unwind_func, &pid);

   ASSERT_EQ(0, ptrace(PTRACE_DETACH, pid, 0, 0))
       << "ptrace detach failed with unexpected error: " << strerror(errno);
 }

 static void RemoteUnwind(void* data) {
   pid_t* pid = reinterpret_cast<pid_t*>(data);

   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);
 }

 TEST_F(UnwindTest, remote_check_for_leaks) {
   RemoteCheckForLeaks(RemoteUnwind);
 }

 static void RemoteUnwindFromPid(void* data) {
   pid_t* pid = reinterpret_cast<pid_t*>(data);

   std::unique_ptr<Regs> regs(Regs::RemoteGet(*pid));
   ASSERT_TRUE(regs.get() != nullptr);

   UnwinderFromPid unwinder(512, *pid);
   ASSERT_TRUE(unwinder.Init(regs->Arch()));
   unwinder.SetRegs(regs.get());

   VerifyUnwind(&unwinder, kFunctionOrder);
 }

 TEST_F(UnwindTest, remote_unwind_for_pid_check_for_leaks) {
   RemoteCheckForLeaks(RemoteUnwindFromPid);
 }

 TEST_F(UnwindTest, from_context) {
   std::atomic_int tid(0);
   std::thread thread([&]() {
     tid = syscall(__NR_gettid);
     OuterFunction(TEST_TYPE_LOCAL_WAIT_FOR_FINISH);
   });

   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());
   ASSERT_EQ(0, 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(signal != SIGSEGV ? TEST_TYPE_REMOTE : TEST_TYPE_REMOTE_WITH_INVALID_CALL);
     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
	/*
	* 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 <android-base/threads.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 {

	enum TestTypeEnum : uint8_t {
	TEST_TYPE_LOCAL_UNWINDER = 0,
	TEST_TYPE_LOCAL_UNWINDER_FROM_PID,
	TEST_TYPE_LOCAL_WAIT_FOR_FINISH,
	TEST_TYPE_REMOTE,
	TEST_TYPE_REMOTE_WITH_INVALID_CALL,
	};

	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;
	// Avoid any function calls because not every instruction will be
	// unwindable.
	// This method of looping is only used when testing a remote unwind.
	while (true) {
	}
	}

	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(Unwinder* unwinder, std::vector<const char*> expected_function_names) {
	unwinder->Unwind();

	for (auto& frame : unwinder->frames()) {
	if (frame.function_name == expected_function_names.back()) {
	expected_function_names.pop_back();
	if (expected_function_names.empty()) {
	break;
	}
	}
	}

	ASSERT_TRUE(expected_function_names.empty()) << ErrorMsg(expected_function_names, unwinder);
	}

	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);
	VerifyUnwind(&unwinder, expected_function_names);
	}

	// 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(TestTypeEnum test_type) {
	if (test_type == TEST_TYPE_LOCAL_WAIT_FOR_FINISH) {
	while (!g_finish.load()) {
	}
	return;
	}
	if (test_type == TEST_TYPE_REMOTE \|\| test_type == TEST_TYPE_REMOTE_WITH_INVALID_CALL) {
	g_ready_for_remote = true;
	g_ready = true;
	if (test_type == TEST_TYPE_REMOTE_WITH_INVALID_CALL) {
	void (*crash_func)() = nullptr;
	crash_func();
	}
	// Avoid any function calls because not every instruction will be
	// unwindable.
	// This method of looping is only used when testing a remote unwind.
	while (true) {
	}
	return;
	}

	std::unique_ptr<Unwinder> unwinder;
	std::unique_ptr<Regs> regs(Regs::CreateFromLocal());
	RegsGetLocal(regs.get());
	std::unique_ptr<Maps> maps;

	if (test_type == TEST_TYPE_LOCAL_UNWINDER) {
	maps.reset(new LocalMaps());
	ASSERT_TRUE(maps->Parse());
	auto process_memory(Memory::CreateProcessMemory(getpid()));
	unwinder.reset(new Unwinder(512, maps.get(), regs.get(), process_memory));
	} else {
	UnwinderFromPid* unwinder_from_pid = new UnwinderFromPid(512, getpid());
	ASSERT_TRUE(unwinder_from_pid->Init(regs->Arch()));
	unwinder_from_pid->SetRegs(regs.get());
	unwinder.reset(unwinder_from_pid);
	}
	VerifyUnwind(unwinder.get(), kFunctionOrder);
	}

	extern "C" void MiddleFunction(TestTypeEnum test_type) {
	InnerFunction(test_type);
	}

	extern "C" void OuterFunction(TestTypeEnum test_type) {
	MiddleFunction(test_type);
	}

	class UnwindTest : public ::testing::Test {
	public:
	void SetUp() override { ResetGlobals(); }
	};

	TEST_F(UnwindTest, local) {
	OuterFunction(TEST_TYPE_LOCAL_UNWINDER);
	}

	TEST_F(UnwindTest, local_use_from_pid) {
	OuterFunction(TEST_TYPE_LOCAL_UNWINDER_FROM_PID);
	}

	static void LocalUnwind(void* data) {
	TestTypeEnum* test_type = reinterpret_cast<TestTypeEnum*>(data);
	OuterFunction(*test_type);
	}

	TEST_F(UnwindTest, local_check_for_leak) {
	TestTypeEnum test_type = TEST_TYPE_LOCAL_UNWINDER;
	TestCheckForLeaks(LocalUnwind, &test_type);
	}

	TEST_F(UnwindTest, local_use_from_pid_check_for_leak) {
	TestTypeEnum test_type = TEST_TYPE_LOCAL_UNWINDER_FROM_PID;
	TestCheckForLeaks(LocalUnwind, &test_type);
	}

	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(TEST_TYPE_REMOTE);
	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, unwind_from_pid_remote) {
	pid_t pid;
	if ((pid = fork()) == 0) {
	OuterFunction(TEST_TYPE_REMOTE);
	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.";

	std::unique_ptr<Regs> regs(Regs::RemoteGet(pid));
	ASSERT_TRUE(regs.get() != nullptr);

	UnwinderFromPid unwinder(512, pid);
	ASSERT_TRUE(unwinder.Init(regs->Arch()));
	unwinder.SetRegs(regs.get());

	VerifyUnwind(&unwinder, kFunctionOrder);

	// Verify that calling the same object works again.

	ASSERT_EQ(0, ptrace(PTRACE_DETACH, pid, 0, 0))
	<< "ptrace detach failed with unexpected error: " << strerror(errno);
	}

	static void RemoteCheckForLeaks(void (unwind_func)(void)) {
	pid_t pid;
	if ((pid = fork()) == 0) {
	OuterFunction(TEST_TYPE_REMOTE);
	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.";

	TestCheckForLeaks(unwind_func, &pid);

	ASSERT_EQ(0, ptrace(PTRACE_DETACH, pid, 0, 0))
	<< "ptrace detach failed with unexpected error: " << strerror(errno);
	}

	static void RemoteUnwind(void* data) {
	pid_t* pid = reinterpret_cast<pid_t*>(data);

	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);
	}

	TEST_F(UnwindTest, remote_check_for_leaks) {
	RemoteCheckForLeaks(RemoteUnwind);
	}

	static void RemoteUnwindFromPid(void* data) {
	pid_t* pid = reinterpret_cast<pid_t*>(data);

	std::unique_ptr<Regs> regs(Regs::RemoteGet(*pid));
	ASSERT_TRUE(regs.get() != nullptr);

	UnwinderFromPid unwinder(512, *pid);
	ASSERT_TRUE(unwinder.Init(regs->Arch()));
	unwinder.SetRegs(regs.get());

	VerifyUnwind(&unwinder, kFunctionOrder);
	}

	TEST_F(UnwindTest, remote_unwind_for_pid_check_for_leaks) {
	RemoteCheckForLeaks(RemoteUnwindFromPid);
	}

	TEST_F(UnwindTest, from_context) {
	std::atomic_int tid(0);
	std::thread thread([&]() {
	tid = syscall(__NR_gettid);
	OuterFunction(TEST_TYPE_LOCAL_WAIT_FOR_FINISH);
	});

	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());
	ASSERT_EQ(0, 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(signal != SIGSEGV ? TEST_TYPE_REMOTE : TEST_TYPE_REMOTE_WITH_INVALID_CALL);
	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