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// Copyright (C) 2019 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 <jni.h>
#include <jvmti.h>
#include <string>
namespace listextensions {
namespace {
// Special art ti-version number. We will use this as a fallback if we cannot get a regular JVMTI
// env.
constexpr jint kArtTiVersion = JVMTI_VERSION_1_2 | 0x40000000;
template <typename T> void Dealloc(jvmtiEnv* env, T* t) {
env->Deallocate(reinterpret_cast<unsigned char*>(t));
}
template <typename T, typename... Rest> void Dealloc(jvmtiEnv* env, T* t, Rest... rs) {
Dealloc(env, t);
Dealloc(env, rs...);
}
void DeallocParams(jvmtiEnv* env, jvmtiParamInfo* params, jint n_params) {
for (jint i = 0; i < n_params; i++) {
Dealloc(env, params[i].name);
}
}
std::ostream& operator<<(std::ostream& os, const jvmtiParamInfo& param) {
os << param.name << " (";
#define CASE(type, name) \
case JVMTI_##type##_##name: \
os << #name; \
break
switch (param.kind) {
CASE(KIND, IN);
CASE(KIND, IN_PTR);
CASE(KIND, IN_BUF);
CASE(KIND, ALLOC_BUF);
CASE(KIND, ALLOC_ALLOC_BUF);
CASE(KIND, OUT);
CASE(KIND, OUT_BUF);
}
os << ", ";
switch (param.base_type) {
CASE(TYPE, JBYTE);
CASE(TYPE, JCHAR);
CASE(TYPE, JSHORT);
CASE(TYPE, JINT);
CASE(TYPE, JLONG);
CASE(TYPE, JFLOAT);
CASE(TYPE, JDOUBLE);
CASE(TYPE, JBOOLEAN);
CASE(TYPE, JOBJECT);
CASE(TYPE, JTHREAD);
CASE(TYPE, JCLASS);
CASE(TYPE, JVALUE);
CASE(TYPE, JFIELDID);
CASE(TYPE, JMETHODID);
CASE(TYPE, CCHAR);
CASE(TYPE, CVOID);
CASE(TYPE, JNIENV);
}
#undef CASE
os << ")";
return os;
}
jint SetupJvmtiEnv(JavaVM* vm) {
jint res = 0;
jvmtiEnv* env = nullptr;
res = vm->GetEnv(reinterpret_cast<void**>(&env), JVMTI_VERSION_1_1);
if (res != JNI_OK || env == nullptr) {
LOG(ERROR) << "Unable to access JVMTI, error code " << res;
res = vm->GetEnv(reinterpret_cast<void**>(&env), kArtTiVersion);
if (res != JNI_OK) {
return res;
}
}
// Get the extensions.
jint n_ext = 0;
jvmtiExtensionFunctionInfo* infos = nullptr;
if (env->GetExtensionFunctions(&n_ext, &infos) != JVMTI_ERROR_NONE) {
return JNI_ERR;
}
LOG(INFO) << "Found " << n_ext << " extension functions";
for (jint i = 0; i < n_ext; i++) {
const jvmtiExtensionFunctionInfo& info = infos[i];
LOG(INFO) << info.id;
LOG(INFO) << "\tdesc: " << info.short_description;
LOG(INFO) << "\targuments: (count: " << info.param_count << ")";
for (jint j = 0; j < info.param_count; j++) {
const jvmtiParamInfo& param = info.params[j];
LOG(INFO) << "\t\t" << param;
}
LOG(INFO) << "\tErrors: (count: " << info.error_count << ")";
for (jint j = 0; j < info.error_count; j++) {
char* name;
CHECK_EQ(JVMTI_ERROR_NONE, env->GetErrorName(info.errors[j], &name));
LOG(INFO) << "\t\t" << name;
Dealloc(env, name);
}
DeallocParams(env, info.params, info.param_count);
Dealloc(env, info.short_description, info.id, info.errors, info.params);
}
// Cleanup the array.
Dealloc(env, infos);
jvmtiExtensionEventInfo* events = nullptr;
if (env->GetExtensionEvents(&n_ext, &events) != JVMTI_ERROR_NONE) {
return JNI_ERR;
}
LOG(INFO) << "Found " << n_ext << " extension events";
for (jint i = 0; i < n_ext; i++) {
const jvmtiExtensionEventInfo& info = events[i];
LOG(INFO) << info.id;
LOG(INFO) << "\tindex: " << info.extension_event_index;
LOG(INFO) << "\tdesc: " << info.short_description;
LOG(INFO) << "\tevent arguments: (count: " << info.param_count << ")";
for (jint j = 0; j < info.param_count; j++) {
const jvmtiParamInfo& param = info.params[j];
LOG(INFO) << "\t\t" << param;
}
DeallocParams(env, info.params, info.param_count);
Dealloc(env, info.short_description, info.id, info.params);
}
// Cleanup the array.
Dealloc(env, events);
env->DisposeEnvironment();
return JNI_OK;
}
jint AgentStart(JavaVM* vm, char* options ATTRIBUTE_UNUSED, void* reserved ATTRIBUTE_UNUSED) {
if (SetupJvmtiEnv(vm) != JNI_OK) {
LOG(ERROR) << "Could not get JVMTI env or ArtTiEnv!";
return JNI_ERR;
}
return JNI_OK;
}
} // namespace
// Late attachment (e.g. 'am attach-agent').
extern "C" JNIEXPORT jint JNICALL Agent_OnAttach(JavaVM* vm, char* options, void* reserved) {
return AgentStart(vm, options, reserved);
}
// Early attachment
extern "C" JNIEXPORT jint JNICALL Agent_OnLoad(JavaVM* jvm, char* options, void* reserved) {
return AgentStart(jvm, options, reserved);
}
} // namespace listextensions
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