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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 <android-base/logging.h>
#include <atomic>
#include <iostream>
#include <iomanip>
#include <jni.h>
#include <jvmti.h>
#include <memory>
#include <string>
#include <vector>
namespace breakpoint_logger {
struct SingleBreakpointTarget {
std::string class_name;
std::string method_name;
std::string method_sig;
jlocation location;
};
struct BreakpointTargets {
std::vector<SingleBreakpointTarget> bps;
};
static void VMInitCB(jvmtiEnv* jvmti, JNIEnv* env, jthread thr ATTRIBUTE_UNUSED) {
BreakpointTargets* all_targets = nullptr;
jvmtiError err = jvmti->GetEnvironmentLocalStorage(reinterpret_cast<void**>(&all_targets));
if (err != JVMTI_ERROR_NONE || all_targets == nullptr) {
env->FatalError("unable to get breakpoint targets");
}
for (const SingleBreakpointTarget& target : all_targets->bps) {
jclass k = env->FindClass(target.class_name.c_str());
if (env->ExceptionCheck()) {
env->ExceptionDescribe();
env->FatalError("Could not find class!");
return;
}
jmethodID m = env->GetMethodID(k, target.method_name.c_str(), target.method_sig.c_str());
if (env->ExceptionCheck()) {
env->ExceptionClear();
m = env->GetStaticMethodID(k, target.method_name.c_str(), target.method_sig.c_str());
if (env->ExceptionCheck()) {
env->ExceptionDescribe();
env->FatalError("Could not find method!");
return;
}
}
err = jvmti->SetBreakpoint(m, target.location);
if (err != JVMTI_ERROR_NONE) {
env->FatalError("unable to set breakpoint");
return;
}
env->DeleteLocalRef(k);
}
}
class ScopedThreadInfo {
public:
ScopedThreadInfo(jvmtiEnv* jvmti_env, JNIEnv* env, jthread thread)
: jvmti_env_(jvmti_env), env_(env), free_name_(false) {
memset(&info_, 0, sizeof(info_));
if (thread == nullptr) {
info_.name = const_cast<char*>("<NULLPTR>");
} else if (jvmti_env->GetThreadInfo(thread, &info_) != JVMTI_ERROR_NONE) {
info_.name = const_cast<char*>("<UNKNOWN THREAD>");
} else {
free_name_ = true;
}
}
~ScopedThreadInfo() {
if (free_name_) {
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(info_.name));
}
env_->DeleteLocalRef(info_.thread_group);
env_->DeleteLocalRef(info_.context_class_loader);
}
const char* GetName() const {
return info_.name;
}
private:
jvmtiEnv* jvmti_env_;
JNIEnv* env_;
bool free_name_;
jvmtiThreadInfo info_;
};
class ScopedClassInfo {
public:
ScopedClassInfo(jvmtiEnv* jvmti_env, jclass c)
: jvmti_env_(jvmti_env),
class_(c),
name_(nullptr),
generic_(nullptr),
file_(nullptr),
debug_ext_(nullptr) {}
~ScopedClassInfo() {
if (class_ != nullptr) {
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(name_));
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(generic_));
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(file_));
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(debug_ext_));
}
}
bool Init() {
if (class_ == nullptr) {
name_ = const_cast<char*>("<NONE>");
generic_ = const_cast<char*>("<NONE>");
return true;
} else {
jvmtiError ret1 = jvmti_env_->GetSourceFileName(class_, &file_);
jvmtiError ret2 = jvmti_env_->GetSourceDebugExtension(class_, &debug_ext_);
return jvmti_env_->GetClassSignature(class_, &name_, &generic_) == JVMTI_ERROR_NONE &&
ret1 != JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
ret1 != JVMTI_ERROR_INVALID_CLASS &&
ret2 != JVMTI_ERROR_MUST_POSSESS_CAPABILITY &&
ret2 != JVMTI_ERROR_INVALID_CLASS;
}
}
jclass GetClass() const {
return class_;
}
const char* GetName() const {
return name_;
}
// Generic type parameters, whatever is in the <> for a class
const char* GetGeneric() const {
return generic_;
}
const char* GetSourceDebugExtension() const {
if (debug_ext_ == nullptr) {
return "<UNKNOWN_SOURCE_DEBUG_EXTENSION>";
} else {
return debug_ext_;
}
}
const char* GetSourceFileName() const {
if (file_ == nullptr) {
return "<UNKNOWN_FILE>";
} else {
return file_;
}
}
private:
jvmtiEnv* jvmti_env_;
jclass class_;
char* name_;
char* generic_;
char* file_;
char* debug_ext_;
};
class ScopedMethodInfo {
public:
ScopedMethodInfo(jvmtiEnv* jvmti_env, JNIEnv* env, jmethodID method)
: jvmti_env_(jvmti_env),
env_(env),
method_(method),
declaring_class_(nullptr),
class_info_(nullptr),
name_(nullptr),
signature_(nullptr),
generic_(nullptr),
first_line_(-1) {}
~ScopedMethodInfo() {
env_->DeleteLocalRef(declaring_class_);
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(name_));
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(signature_));
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(generic_));
}
bool Init() {
if (jvmti_env_->GetMethodDeclaringClass(method_, &declaring_class_) != JVMTI_ERROR_NONE) {
return false;
}
class_info_.reset(new ScopedClassInfo(jvmti_env_, declaring_class_));
jint nlines;
jvmtiLineNumberEntry* lines;
jvmtiError err = jvmti_env_->GetLineNumberTable(method_, &nlines, &lines);
if (err == JVMTI_ERROR_NONE) {
if (nlines > 0) {
first_line_ = lines[0].line_number;
}
jvmti_env_->Deallocate(reinterpret_cast<unsigned char*>(lines));
} else if (err != JVMTI_ERROR_ABSENT_INFORMATION &&
err != JVMTI_ERROR_NATIVE_METHOD) {
return false;
}
return class_info_->Init() &&
(jvmti_env_->GetMethodName(method_, &name_, &signature_, &generic_) == JVMTI_ERROR_NONE);
}
const ScopedClassInfo& GetDeclaringClassInfo() const {
return *class_info_;
}
jclass GetDeclaringClass() const {
return declaring_class_;
}
const char* GetName() const {
return name_;
}
const char* GetSignature() const {
return signature_;
}
const char* GetGeneric() const {
return generic_;
}
jint GetFirstLine() const {
return first_line_;
}
private:
jvmtiEnv* jvmti_env_;
JNIEnv* env_;
jmethodID method_;
jclass declaring_class_;
std::unique_ptr<ScopedClassInfo> class_info_;
char* name_;
char* signature_;
char* generic_;
jint first_line_;
friend std::ostream& operator<<(std::ostream& os, ScopedMethodInfo const& method);
};
std::ostream& operator<<(std::ostream& os, const ScopedMethodInfo* method) {
return os << *method;
}
std::ostream& operator<<(std::ostream& os, ScopedMethodInfo const& method) {
return os << method.GetDeclaringClassInfo().GetName() << "->" << method.GetName()
<< method.GetSignature() << " (source: "
<< method.GetDeclaringClassInfo().GetSourceFileName() << ":" << method.GetFirstLine()
<< ")";
}
static void BreakpointCB(jvmtiEnv* jvmti_env,
JNIEnv* env,
jthread thread,
jmethodID method,
jlocation location) {
ScopedThreadInfo info(jvmti_env, env, thread);
ScopedMethodInfo method_info(jvmti_env, env, method);
if (!method_info.Init()) {
LOG(ERROR) << "Unable to get method info!";
return;
}
LOG(WARNING) << "Breakpoint at location: 0x" << std::setw(8) << std::setfill('0') << std::hex
<< location << " in method " << method_info << " thread: " << info.GetName();
}
static std::string SubstrOf(const std::string& s, size_t start, size_t end) {
if (end == std::string::npos) {
end = s.size();
}
if (end == start) {
return "";
}
CHECK_GT(end, start) << "cannot get substr of " << s;
return s.substr(start, end - start);
}
static bool ParseSingleBreakpoint(const std::string& bp, /*out*/SingleBreakpointTarget* target) {
std::string option = bp;
if (option.empty() || option[0] != 'L' || option.find(';') == std::string::npos) {
LOG(ERROR) << option << " doesn't look like it has a class name";
return false;
}
target->class_name = SubstrOf(option, 1, option.find(';'));
option = SubstrOf(option, option.find(';') + 1, std::string::npos);
if (option.size() < 2 || option[0] != '-' || option[1] != '>') {
LOG(ERROR) << bp << " doesn't seem to indicate a method, expected ->";
return false;
}
option = SubstrOf(option, 2, std::string::npos);
size_t sig_start = option.find('(');
size_t loc_start = option.find('@');
if (option.empty() || sig_start == std::string::npos) {
LOG(ERROR) << bp << " doesn't seem to have a method sig!";
return false;
} else if (loc_start == std::string::npos ||
loc_start < sig_start ||
loc_start + 1 >= option.size()) {
LOG(ERROR) << bp << " doesn't seem to have a valid location!";
return false;
}
target->method_name = SubstrOf(option, 0, sig_start);
target->method_sig = SubstrOf(option, sig_start, loc_start);
target->location = std::stol(SubstrOf(option, loc_start + 1, std::string::npos));
return true;
}
static std::string RemoveLastOption(const std::string& op) {
if (op.find(',') == std::string::npos) {
return "";
} else {
return SubstrOf(op, op.find(',') + 1, std::string::npos);
}
}
// Fills targets with the breakpoints to add.
// Lname/of/Klass;->methodName(Lsig/of/Method)Lreturn/Type;@location,<...>
static bool ParseArgs(const std::string& start_options,
/*out*/BreakpointTargets* targets) {
for (std::string options = start_options;
!options.empty();
options = RemoveLastOption(options)) {
SingleBreakpointTarget target;
std::string next = SubstrOf(options, 0, options.find(','));
if (!ParseSingleBreakpoint(next, /*out*/ &target)) {
LOG(ERROR) << "Unable to parse breakpoint from " << next;
return false;
}
targets->bps.push_back(target);
}
return true;
}
enum class StartType {
OnAttach, OnLoad,
};
static jint AgentStart(StartType start,
JavaVM* vm,
char* options,
void* reserved ATTRIBUTE_UNUSED) {
jvmtiEnv* jvmti = nullptr;
jvmtiError error = JVMTI_ERROR_NONE;
{
jint res = 0;
res = vm->GetEnv(reinterpret_cast<void**>(&jvmti), JVMTI_VERSION_1_1);
if (res != JNI_OK || jvmti == nullptr) {
LOG(ERROR) << "Unable to access JVMTI, error code " << res;
return JNI_ERR;
}
}
void* bp_target_mem = nullptr;
error = jvmti->Allocate(sizeof(BreakpointTargets),
reinterpret_cast<unsigned char**>(&bp_target_mem));
if (error != JVMTI_ERROR_NONE) {
LOG(ERROR) << "Unable to alloc memory for breakpoint target data";
return JNI_ERR;
}
BreakpointTargets* data = new(bp_target_mem) BreakpointTargets;
error = jvmti->SetEnvironmentLocalStorage(data);
if (error != JVMTI_ERROR_NONE) {
LOG(ERROR) << "Unable to set local storage";
return JNI_ERR;
}
if (!ParseArgs(options, /*out*/data)) {
LOG(ERROR) << "failed to parse breakpoint list!";
return JNI_ERR;
}
jvmtiCapabilities caps{};
caps.can_generate_breakpoint_events = JNI_TRUE;
caps.can_get_line_numbers = JNI_TRUE;
caps.can_get_source_file_name = JNI_TRUE;
caps.can_get_source_debug_extension = JNI_TRUE;
error = jvmti->AddCapabilities(&caps);
if (error != JVMTI_ERROR_NONE) {
LOG(ERROR) << "Unable to set caps";
return JNI_ERR;
}
jvmtiEventCallbacks callbacks{};
callbacks.Breakpoint = &BreakpointCB;
callbacks.VMInit = &VMInitCB;
error = jvmti->SetEventCallbacks(&callbacks, static_cast<jint>(sizeof(callbacks)));
if (error != JVMTI_ERROR_NONE) {
LOG(ERROR) << "Unable to set event callbacks.";
return JNI_ERR;
}
error = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
JVMTI_EVENT_BREAKPOINT,
nullptr /* all threads */);
if (error != JVMTI_ERROR_NONE) {
LOG(ERROR) << "Unable to enable breakpoint event";
return JNI_ERR;
}
if (start == StartType::OnAttach) {
JNIEnv* env = nullptr;
jint res = 0;
res = vm->GetEnv(reinterpret_cast<void**>(&env), JNI_VERSION_1_2);
if (res != JNI_OK || env == nullptr) {
LOG(ERROR) << "Unable to get jnienv";
return JNI_ERR;
}
VMInitCB(jvmti, env, nullptr);
} else {
error = jvmti->SetEventNotificationMode(JVMTI_ENABLE,
JVMTI_EVENT_VM_INIT,
nullptr /* all threads */);
if (error != JVMTI_ERROR_NONE) {
LOG(ERROR) << "Unable to set event vminit";
return JNI_ERR;
}
}
return JNI_OK;
}
// Late attachment (e.g. 'am attach-agent').
extern "C" JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM *vm, char* options, void* reserved) {
return AgentStart(StartType::OnAttach, vm, options, reserved);
}
// Early attachment
extern "C" JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM* jvm, char* options, void* reserved) {
return AgentStart(StartType::OnLoad, jvm, options, reserved);
}
} // namespace breakpoint_logger